Due to the diffusion of severe pathogens, everyday life is exposed to the risks of contracting severe diseases. For this reason, efficient antimicrobial surfaces are of paramount importance. In this work we present the first evidences of a new technique to obtain an antibacterial ultra high molecular weight polyethylene based on a non- stoichiometric, visible light responsive, titanium oxide coating. The coating was obtained through a process in which titanium ions, resulting from laser ablation of a corresponding target, were accelerated and implanted on the samples. The samples were tested against a Staphylo- coccus aureus strain, in order to assay their antimicrobial efficacy. Results show that this treatment strongly dis- courages bacterial colonization of the treated surfaces.

Several hydroid species live associated with many organisms, including bacteria. Hydroid-bacteria associations were searched for in twenty Hydrozoa species that were collected in the northern Ionian Sea and observed under blue light excitation. Of these, six showed high fluorescence on the outer perisarc, five appeared medium fluorescent, four were slightly fluorescent, and five did not show any fluorescence. Luminous bacteria were isolated and counted from the surface of the fluorescent hydroids. Their association with hydrozoan species could be explained by their feeding activity on the chitinous structures of the perisarc, as previous research on the hydroid Aglaophenia octodonta showed. Moreover, microalgae were always recovered together with luminous bacteria in the strongly, medium and slightly fluorescent hydroids. Further studies will be undertaken to characterize the luminous bacteria isolated from the surface of the examined hydrozoans as well as to better understand whether their interaction with hydroids is only related to chitin utilization or if their coexistence with microalgae in hydrozoans has an ecological meaning.

A previously unknown association between a luminous Vibrio sp., taxonomically related to the species Vibrio harveyi and a common member of the shallow/mid water communities of the Mediterranean Sea, the hydrozoan Clytia linearis is described. All the specimens of C. linearis observed under blue light excitation showed both a natural luminescence appearing as a series of fine dots due to clytin, and a clear fluorescence on the external side of the perisarc around the colonies due to the presence of luminous bacteria. Luminous bacteria were isolated from the surface of C. linearis, their phenotypic characterization as isolates was performed by several morphological, biochemical, and cultural tests, completed with 16S rDNA sequence analysis. All the isolates were referred to a Vibrio sp. taxonomically related to V. harveyi. The association of the V. harveyi-related species with C. linearis, as already suggested for another hydroid, Aglaophenia octodonta, could be explained with the activity of these bacteria of feeding on the chitinous structures present in these hydroids. Moreover, the adhesion of the luminous bacterium (here referred to as Vibrio sp. CL1) on C. linearis may contribute to the survival of this Vibrio species in the marine environment providing a suitable growth habitat.

In aquatic environments, vibrios are among the most abundant culturable microbes found either as free-living or associated with several marine organisms. The diseases due to some pathogenic vibrios are increasing worldwide thus the understanding of the mechanisms related to their spread is critically needed. In the present study, the abundance as well as the diversity of culturable vibrios associated to the surfaces of the green alga Caulerpa cylindracea (Sonder) were analyzed during different stages of algal development. The Vibrio densities ranged from 1.9 x 10(3) CFU to 2.2 x 10(4) CFU mL(-1). The Vibrio strains isolated from C. cylindracea surfaces were assigned to: Vibrio tubiashii, Vibrio neptunius, Vibrio rotiferianus, Vibrio communis, Vibrio owensii, Vibrio jasicida, Vibrio harveyi, Vibrio maritimus, Vibrio diabolicus, Vibrio campbellii, Vibrio pomeroyi, Vibrio crassostreae, and Vibrio aestivus. Although some of the species recovered can be pathogenic to benthic marine organisms, none is considered human pathogens. Only few of the isolated vibrios (V. campbellii, V. aestivus, V. pomeroyi and V. crassostreae) have a sporadic presence on the algal surfaces (i.e. they were found only during one sampling event) while most of the isolates were found in all the four sampling times. The association of these last Vibrio species and the surfaces of C cylindracea needs to be elucidated in order also to ascertain whether vibrios might contribute to the successful spreading of the algal species.

We show that, in particular experimental conditions, the time course of the radiant fluxes, measured from a bioluminescent emission of a Vibrio harveyi related strain, collapse after suitable rescaling onto the Gumbel distribution of extreme value theory. We argue that the activation times of the strain luminous emission follow the universal behavior described by this statistical law, in spite of the fact that no extremal process is known to occur.

We present an effective dynamical model for the onset of bacterial bioluminescence, one of the most studied quorum sensing-mediated traits. Our model is built upon simple equations that describe the growth of the bacterial colony, the production and accumulation of autoinducer signal molecules, their sensing within bacterial cells, and the ensuing quorum activation mechanism that triggers bioluminescent emission. The model is directly tested to quantitatively reproduce the experimental distributions of photon emission times, previously measured for bacterial colonies of Vibrio jasicida, a luminescent bacterium belonging to the Harveyi clade, growing in a highly drying environment. A distinctive and novel feature of the proposed model is bioluminescence 'quenching' after a given time elapsed from activation. Using an advanced fitting procedure based on the simulated annealing algorithm, we are able to infer from the experimental observations the biochemical parameters used in the model. Such parameters are in good agreement with the literature data. As a further result, we find that, at least in our experimental conditions, light emission in bioluminescent bacteria appears to originate from a subtle balance between colony growth and quorum activation due to autoinducers diffusion, with the two phenomena occurring on the same time scale. This finding is consistent with a negative feedback mechanism previously reported for Vibrio harveyi.

The possibility of producing biogas and methane from two phases olive pomace was considered using anaerobic digestion and the microbial characteristic of digestate for the agrarian use was analyzed. In the work, the main aim was to obtain biogas, made from at least 50% methane, and a digestate that can be used in the field of agronomy, from the anaerobic digestion of the substrates. The tests were carried out by digesting different mixtures of the two-phase pomace, mulberry leaves and mud civil wastewater (pre-digested) in a batch system and in anaerobic mesophilic conditions (35 °C). The substrates were properly homogenized in order to obtain mixtures of known and uniform composition. The initial and final STi (Total Solids) and initial SVi (Volatile Solids), the concentration of chemical oxygen demand and total phenols were measured and the process yield (m3/t SV) was quantified with standard procedure. The objectives of the study were the analysis of microbial biodiversity developed during fermentation of mixtures based products and the microbial communities corresponding to Eubacteria, Archaea and Fungiwas analyzed. The suitability of the digestate for agronomical use was evaluated by estimating pathogens bacteria that may be present and by index of inhibition of plant organisms model.

Vibrios are among the most abundant culturable microbes in aquatic environments. They can be either free-living in the water column or associated with several marine organisms as mutualists, saprophytes, or parasites. In the present study we analysed vibrios abundance and diversity in the mucus of the polychaete Myxicola infundibulum, complementing culture-based with molecular methods. Vibrios reached 4.6 × 103 CFU mL-1 thus representing a conspicuous component of the heterotrophic culturable bacteria. In addition, luminous vibrios accounted for about 60 % of the total culturable vibrios in the mucus. The isolates were assigned to: Vibrio gigantis, Vibrio fischeri, Vibrio jasicida, Vibrio crassostreae, Vibrio kanaloae, and Vibrio xuii. Two Vibrio isolates (MI-13 and MI-15) may belong to a new species. We also tested the ability of the Vibrio isolates to grow on M. infundibulum mucus as the sole carbon source. All strains showed appreciable growth in the presence of mucus, leading us to conclude that this matrix, which is abundant and covers the animal entirely, may represent a microcosm and a food source for some bacteria, playing a crucial role in the structuring of a mucus-associated beneficial microbial community. Moreover, the trophic relationship between vibrios and M. infundibulum mucus could be enhanced by the protection that mucus offers to vibrios. The results of this study represent a contribution to the growing evidence for complex and dynamic invertebrate-microbe associations present in nature and highlight the importance of exploring relationships that Vibrio species establish with marine invertebrates

The chemical composition and fatty acid content of both white sorghum hybrids and pure lines where grown in various areas of the world were studied. Various attributes were investigated including moisture, protein, carbohy- drate, dietary fiber, fat contents, and fatty acid composition. Slight variations in both protein and in fiber contents were observed among cultivars. Linoleic, oleic and palmitic were the most abundant fatty acids in all samples with little difference in their percentage content among the cultivars. Enzyme-linked immunosorbent assays (ELISA) demonstrated, for all sorghum flours analyzed, the absence of toxic protein sequences for celiac patients. The present results demonstrate that food-grade sorghum varieties are potentially able to be grown in Mediterranean countries in addition to regions where sorghum has been traditionally produced, i.e. either in arid tropical and sub- tropical regions of Africa and Asia or in dry regions of America.

The molecular mechanisms altered by the traditional mutation and screening approach during the improvement of antibiotic-producing microorganisms are still poorly understood although this information is essential to design rational strategies for industrial strain improvement. In this study, we applied comparative genomics to identify all genetic changes occurring during the development of an erythromycin overproducer obtained using the traditional mutate-and- screen method.Compared with the parental Saccharopolyspora erythraea NRRL 2338, the genome of the overproducing strain presents 117 deletion, 78 insertion and 12 transposition sites, with 71 insertion/deletion sites mapping within coding sequences (CDSs) and generating frame-shift mutations. Single nucleotide variations are present in 144 CDSs. Overall, the genomic variations affect 227 proteins of the overproducing strain and a considerable number of mutations alter genes of key enzymes in the central carbon and nitrogen metabolism and in the biosynthesis of secondary metabolites, resulting in the redirection of common precursors toward erythromycin biosynthesis. Interestingly, several mutations inactivate genes coding for proteins that play fundamental roles in basic transcription and translation machineries including the transcription anti-termination factor NusB and the transcription elongation factor Efp. These mutations, along with those affecting genes coding for pleiotropic or pathway-specific regulators, affect global expression profile as demonstrated by a comparative analysis of the parental and overproducer expression profiles. Genomic data, finally, suggest that the mutate-and-screen process might have been accelerated by mutations in DNA repair genes.This study helps to clarify the mechanisms underlying antibiotic overproduction providing valuable information about new possible molecular targets for rationale strain improvement.

Rifamycins are mainstay agents in treatment of many widespread diseases, but how an improved rifamycin producer can be created is still incompletely understood. Here, we describe a comparative genomic approach to investigate the mutational patterns introduced by the classical mutate-and-screen method in the genome of an improved rifamycin producer. Comparing the genome of the rifamycin B overproducer Amycolatopsis mediterranei HP-130 with those of the reference strains A. mediterranei S699 and U32, we identified 250 variations, affecting 227 coding sequences (CDS), 109 of which were HP-130-specific since they were absent in both S699 and U32. Mutational and transcriptional patterns indicated a series of genomic manipulations that not only proved the causative effect of mutB2 (coding for methylmalonyl-CoA mutase large subunit) and argS2 (coding for arginyl tRNA synthetase) mutations on the overproduction of rifamycin, but also constituted a rational strategy to genetically engineer a reference strain into an overproducer.

Background: A chemical cross-talk between plants and insects is required in order to achieve a successful co-adaptation. In response to herbivory, plants produce specific compounds, and feeding insects respond adequately7 to molecules produced by plants. Here we show the role of the gut microbial community of the mint beetle Chrysolina herbacea in the chemical cross-talk with Mentha aquatica (or watermint). Results: By using two-dimensional gas chromatography-mass spectrometry we first evaluated the chemical patterns of both M. aquatica leaf and frass volatiles extracted by C. herbacea males and females feeding on plants, and observed marked differences between males and females volatiles. The sex-specific chemical pattern of the frass paralleled with sex-specific distribution of cultivable gut bacteria. Indeed, all isolated gut bacteria from females belonged to either α- or γ-Proteobacteria, whilst those from males were γ-Proteobacteria or Firmicutes. We then demonstrated that five Serratia marcescens strains from females possessed antibacterial activity against bacteria from males belonging to Firmicutes suggesting competition by production of antimicrobial compounds. By in vitro experiments, we lastly showed that the microbial communities from the two sexes were associated to specific metabolic patterns with respect to their ability to biotransform M. aquatica terpenoids, and metabolize them into an array of compounds with possible pheromone activity. Conclusions: Our data suggest that cultivable gut bacteria of Chrysolina herbacea males and females influence the volatile blend of herbivory induced Mentha aquatica volatiles in a sex-specific way.

The growing resistance of many strains of bacteria to antibiotics and antiseptics is becoming a serious problem in medicine. Nano-silver is one of the most prominent products in medicine because it exhibits unusual physicochemical properties and a strong biological activity. In this work an innovative silver deposition technology was applied to temporary polyurethane catheters for haemodialysis. The working conditions of catheters were reproduced through laboratory equipment that ensured the flow of deionized water and simulated body fluid inside the lumina at corporeal temperature. The growth and the adhesion of Staphylococcus aureus on the surface of the device were studied through fluorescence microscopy. ICP-AES was adopted to calculate the amount of silver released from the substrate. The stability of the coating during the whole working life of the device was demonstrated through thermo-gravimetric analysis.

Abstract: In recent years, several episodes of mass mortality of sessile epibenthic invertebrates, including sponges, have been recorded worldwide. In the present study, we report a disease event on Ircinia variabilis recorded in September 2009 along the southern Adriatic and Ionian seas (Apulian coast), with the aim to quantify the mortality incidence on the sponge population, to investigate the effect of the disease on the sponge tissues and to assess whether the disease is associated with vibrios proliferation. The injured sponges showed wide necrotic areas on the surface or disruption of the body in several portions. Necrotic areas were whitish and often were covered with a thin mucous coat formed by bacteria. In the most affected specimens, sponge organisation resulted partial or complete loss, with the final exposure of the dense skeletal network of spongine fibres to the environment. The results of microbiological cultural analysis using in parallel Marine Agar 2216 and thiosulphate/citrate/bile salts/sucrose agar demonstrated that, in affected specimens, vibrios represented 15.8 % of the total I. variabilis surface culturable bacteria. Moreover, all the isolated vibrios, grown from the wide whitish areas that characterize the surface of the diseased sponges, were identified, and their assignment to the Vibrio rotiferianus was consistent with phylogenetic analysis and data of morphological, cultural and biochemical tests. Studies on V. rotiferianus have shown that its pathogenicity, with respect to various aquatic organisms, is higher than that of Vibrio harveyi. The factors triggering the disease outbreak in Ircinia variabilis populations remain unclear. At present, we can hypothesize the involvement in the disease of a synergetic mechanism that, under stressful physiological conditions (high temperature, elevated nutrients and reduced water flow), induces sponge pathogens, in our case V. rotiferanius, to become virulent, making sponges unable to control their proliferation. Additional studies are needed to understand the etiological processes as well as the factors involved in sponges recovering from this epidemic event allowing them to face mass mortality. A drastic reduction of sponge-specific representatives could have marked a negative impact on the environmental health on account of their role in the sea remediation processes as filter-feeding organisms.

In this study, the evidence of electron-dense magnetic inclusions with polyhedral shape in the cytoplasm of Harveyi clade Vibrio strain PS1, a bioluminescent bacterium living in symbiosis with marine organisms, led us to investigate the behavior of this bacterium under exposure to static magnetic fields ranging between 20 and 2000 Gauss. When compared to sham-exposed, the light emission of magnetic field-exposed bacteria growing on solid medium at 18°C ±0.1°C was increased up to two-fold as a function of dose and growth phase. Stimulation of bioluminescence by magnetic field was more pronounced during the post-exponential growth and stationary phase, and was lost when bacteria were grown in the presence of the iron chelator deferoxamine, which caused disassembly of the magnetic inclusions suggesting their involvement in magnetic response. As in luminescent Vibrio spp. bioluminescence is regulated by quorum sensing, possible effects of magnetic field exposure on quorum sensing were investigated. Measurement of mRNA levels by reverse transcriptase real time-PCR demonstrated that luxR regulatory gene and luxCDABE operon coding for luciferase and fatty acid reductase complex were significantly up-regulated in magnetic field-exposed bacteria. In contrast, genes coding for a type III secretion system, whose expression was negatively affected by LuxR, were down-regulated. Up-regulation of luxR paralleled with down-regulation of small RNAs that mediate destabilization of luxR mRNA in quorum sensing signaling pathways. The results of experiments with the well-studied Vibrio campbellii strain BB120 (originally classified as Vibrio harveyi) and derivative mutants unable to synthesize autoinducers suggest that the effects of magnetic fields on quorum sensing may be mediated by AI-2, the interspecies quorum sensing signal molecule.

Rifampin chemoprophylaxis against Neisseria meningitidis infections led to the onset of rifampin resistance in clinical isolates harboring point mutations in the rpoB gene, coding for the RNA polymerase β chain. These resistant strains are rare in medical practice, suggesting their decreased fitness in the human host. In this study, we isolated rifampin-resistant rpoB mutants from hypervirulent serogroup C strain 93/4286 and analyzed their different properties, including the ability to grow/survive in different culture media and in differentiated THP-1 human monocytes and to compete with the wild-type strain in vitro. Our results demonstrate that different rpoB mutations (H553Y, H553R, and S549F) may have different effects, ranging from low- to high-cost effects, on bacterial fitness in vitro. Moreover, we found that the S549F mutation confers temperature sensitivity, possibly explaining why it is observed very rarely in clinical isolates. Comparative high-throughput RNA sequencing analysis of bacteria grown in chemically defined medium demonstrated that the low-cost H553Y substitution resulted in global transcriptional changes that functionally mimic the stringent response. Interestingly, many virulence-associated genes, including those coding for meningococcal type IV pili, porin A, adhesins/invasins, IgA protease, two-partner secretion system HrpA/HrpB, enzymes involved in resistance to oxidative injury, lipooligosaccharide sialylation, and capsular polysaccharide biosynthesis, were downregulated in the H553Y mutant compared to their level of expression in the wild-type strain. These data might account for the reduced capacity of this mutant to grow/survive in differentiated THP-1 cells and explain the rarity of H553Y mutants among clinical isolates.

Polymorphonuclear neutrophil leucocytes (PMNs) are a critical part of innate immune defence against bac- terial pathogens, and only a limited subset of microbes can escape killing by these phagocytic cells. Here we show that Neisseria meningitidis, a leading cause of septicaemia and meningitis, can avoid killing by PMNs and this is dependent on the ability of the bacterium to acquire L-glutamate through its GltT uptake system. We demonstrate that the uptake of available L- glutamate promotes N. meningitidis evasion of PMN reactive oxygen species produced by the oxidative burst. In the meningococcus, L-glutamate is converted to glutathione, a key molecule for maintaining intrac- ellular redox potential, which protects the bacterium from reactive oxygen species such as hydrogen per- oxide. We show that this mechanism contributes to the ability of N. meningitidis to cause bacteraemia, a criti- cal step in the disease process during infections caused by this important human pathogen.

With the beginning of the idiophase the highly phosphorylated guanylic nucleotides guanosine 5'-diphosphate 3'-diphosphate (ppGpp) and guanosine 5'-triphosphate 3'-diphosphate (pppGpp), collectively referred to as (p)ppGpp, activate stress survival adaptation programmes and trigger secondary metabolism in actinomycetes. The major target of (p)ppGpp is the RNA polymerase, where it binds altering the enzyme activity. In this study analysis of the polynucleotide phosphorylase (PNPase)-encoding gene pnp mRNA, in Nonomuraea sp. ATCC 39727 wild-type, constitutively stringent and relaxed strains, led us to hypothesize that in actinomycetes (p)ppGpp may modulate gene expression at the level of RNA decay also. This hypothesis was supported by: (i) in vitro evidence that ppGpp, at physiological levels, inhibited both polynucleotide polymerase and phosphorolytic activities of PNPase in Nonomuraea sp., but not in Escherichia coli, (ii) in vivo data showing that the pnp mRNA and the A40926 antibiotic cluster-specific dpgA mRNA were stabilized during the idiophase in the wild-type strain but not in a relaxed mutant and (iii) measurement of chemical decay of pulse-labelled bulk mRNA. The results of biochemical tests suggest competitive inhibition of ppGpp with respect to nucleoside diphosphates in polynucleotide polymerase assays and mixed inhibition with respect to inorganic phosphate when the RNA phosphorolytic activity was determined.

The spreading of pathogens represents a serious threat for human beings. Consequently, efficient antimicrobial surfaces are needed in order to reduce risks of contracting severe diseases. In this work we present the first evidences of a new technique to obtain a highly antibacterial Ultra High Molecular Weight Polyethylene (UHMWPE) based on a non-stoichiometric titanium oxide coating, visible-light responsive, obtained through ion implantation.

Both academic and industrial laboratories currently use constraint - based reconstruction methods to predict optimal genetic modifications aiming at improving the yield of chemical production. Streptomyces ambofaciens, a prolific producer of bioactive compounds has been studied with different modeling tools . The interest is linked to its ability to produce a wide range of secondary metabolites such as spiramycin, kinamycin, antimycin and stambomycins, and novel polyketides with antibacterial and antiproliferative activities. In this study, the metabolic pattern of Streptomyces ambofaciens has been globally explored: a set of candidate overexpression gene targets supposed to lead to spiramycin overproduction have been evidenced through metabolic modeling. Model predictions were experimentally validated by genetic manipulation of the ethylmalonyl-CoA metabolic node, providing evidence that spiramycin productivity may be increased by enhancing the carbon flow through this pathway. The goal was achieved by over - expressing the ccr paralog srm4 in an ad hoc engineered plasmid. The first metabolic reconstruction of S. ambofaciens and the successful experimental validation of model predictions have been described and the validity and the importance of in silico modeling tools for the overproduction of molecules with a biotechnological interest demonstrated. As a result, the proposed metabolic reconstruction represents a solid platform for the future exploitation of S. ambofaciens biotechnological potential.

Lindane is an organochlorine pesticide belonging to persistent organic pollutants (POPs) that has been widely used to treat agricultural pests. It is of particular concern because of its toxicity, persistence and tendency to bioaccumulate in terrestrial and aquatic ecosystems. In this context, we assessed the role of bacteria associated with the sponge Hymeniacidon perlevis in lindane degradation. Seven bacteria isolates were characterized and identified. These isolates showed a remarkable capacity to utilize lindane as a sole carbon source leading to a percentage of residual lindane ranging from 3% to 13% after 12 days of incubation with the pesticide. The lindane metabolite, 1,3-6-pentachloro-cyclohexene, was identified as result of lindane degradation and determined by gas chromatography-mass spectrometry (GC-MS). The bacteria capable of lindane degradation were identified on the basis of the phenotypic characterization by morphological, biochemical and cultural tests, completed with 16S rDNA sequence analysis, and assigned to Mameliella phaeodactyli, Pseudovibrioascidiaceicola, Oceanicaulis stylophorae, Ruegeria atlantica and to three new uncharacterized species. The results obtained are a prelude to the development of future strategies for the in situ bioremediation of lindane.

Bacteria synthesise an extremely rich repertoire of odorous compounds. Unfortunately this feature is not much known and bacteria are more often associated with the bad smell of rotting material. The focus of this review is on the capability of bacteria to synthesize odorous volatiles, either when they are free-living in soil and aquatic environments or when they establish symbiotic association with plants and animals, with specific reference to humans. In particular, the biological and ecological significance of bacterial volatiles and their biotechnological perspectives are covered in this present work.

Mineral nutrients play a fundamental role in the biochemical and physiological functions of biological systems. Cereals may especially be an important source of essential minerals in view of their large daily intake both for human health and nutrition. Sorghum, among the cereals, is a major crop being used for food, feed and industrial purposes worldwide. The objective of this study was to determine the mineral contents in grains of seven white food-grade sorghum hybrids, bred and adapted for growth in the central USA and grown in a Mediterranean area of Southern Italy. The seven hybrids were analyzed for grain ash and for minerals contents. Nutritionally, essential macro-, micro- and trace elements content were investigated. The analysis of essential elements was performed by mass spectrometry using a mix solution of internal isotopes standard. The results demonstrated that food-grade sorghum was characterized by high Mg, Fe and Zn content, high K:Na ratio and low Ca:P ratio, compared to other crops, due to the fact that the grain mineral contents of crop species are influenced by the effects of genotypes and environments. Significant variations in the essential elements content were found among the hybrids which allowed us to divide them into three distinct groups on the basis of their mineral profile by cluster analysis. These results are discussed with reference to the importance of minerals in human nutrition and suggest that, like wheat, it is possible to plan research programs for the improvement and selection of sorghum hybrids with high micronutrients content.

The nutrient composition, fatty acid content and mineral content of six white food-grade sorghum hybrids selected in either Argentina or Bolivia, and grown in a Mediterranean area of Southern Italy were studied. The six hybrids were analyzed for various attributes including moisture, protein, carbohydrate, dietary fiber, fat contents, fatty acid composition, and mineral content. Slight variations in both protein and in fiber contents were observed among hybrids. Linoleic, oleic and palmitic were the most abundant fatty acids in all samples with noticeable difference in their percentage content between both hybrids from Argentina and Bolivia. Slight variations in the content of the elements were found among the six white sorghum hybrids examined, and K, Fe, and Sb were, respectively, the most abundant macro-element, micro-element and trace element in all analyzed hybrids. These results are discussed in the context of the importance of the white food-grade sorghum in human nutrition, and of the opportunity to select the best varieties from the point of view of nutritional content.

Caulerpa cylindracea (Sonder), among the most successful marine bio-invaders on a global scale, poses severe threats to biodiversity. However, the effects of this seaweed on the quantity and the biochemical composition of sedimentary organic matter are still poorly known. Since the whole set of sedimentary features affects the availability of substrates for benthic microbial communities, we: i) investigated the biochemical composition of sediments colonized and not-colonized by C. cylindracea, and ii) compared the metabolic patterns of the microbial communities associated with C. cylindracea and in the sediments colonized and not-colonized by the seaweed. Our results show that C. cylindracea can influence the quantity and biochemical composition of sedimentary organic matter (OM), and that microbial populations associated with colonized sediments do have specific metabolic patterns and degradation capacities. Caulerpa cylindracea can also influence the metabolic patterns of the microbial community specifically adapted to degrade compounds released by the seaweed itself, with possible consequences on C cycling

We discuss the mechanisms of bacterial Quorum Sensing, the biophysical phenomenon point- ing out a social behavior in bacteria, highlighting thus the very complex structure of these sys- tems. Actually, bacterial bioluminescence is an example of a quorum sensing mediated prop- erty. We show that the distribution of the activation times of the bioluminescent emission follows the universal behavior described by the Gumbel distribution of extreme value statis- tics. We provide further evidence on the system size scaling of bioluminescence, showing that the relation between cell density and total number of photons radiated by bacteria is highly non-linear.

We present the study and the analyses of a transmission line for radiofrequency (RF) irradiation of bacteria belonging to Vibrio harveyi-related strain PS1, a bioluminescent bacterium living in symbiosis with many marine organisms. The bioluminescence represents a new biologic indicator which is useful for studying the behaviour of living samples in the presence of RF waves due to the modern communication systems. A suitable transmission line, used as an irradiating cell and tested up to the maximum frequency used by the global system for mobile communications and universal mobile telecommunications system transmissions, was characterized. In this experiment, the RF voltage applied to the transmission line was 1V. Due to short dimensions of the line and the applied high frequencies, standing waves were produced in addition to progressing waves and the electric field strength varies particularly along the longitudinal direction. The magnetic field map was not strongly linked to the electric one due to the presence of standing waves and of the outgoing irradiation. RF fields were measured by two homemade suitable probes able to diagnostic fields of high frequency. The field measurements were performed without any specimens inside the line. Being our sample made of living matter, the real field was modified and its value was estimated by a simulation code. The bioluminescence experiments were performed only at 900MHz for two different measured electric fields, 53 and 140V/m. The light emission was measured right from the beginning and after 7 and 25 h. Under RF irradiation, we found that the bioluminescence activity decreased. Compared with the control sample, the diminution was 6.8% and 44% after 7 and 25 h of irradiation, respectively, both with the low or high field. No changes of the survival factor for all the samples were observed. Besides, to understand the emission processes, we operated the deconvolution of the spectra by two Gaussian curves. The Gaussian peaks were approximately centered at 460 nm and 490 nm. The 490 nm peak was higher than the control one. Under RF, the 490 nm peak decreased compared to the 460 nm one. The decreasing was stronger for the sample in the higher field. The ratio of the emission area of the 490 nm to 460 nm was 5 for the control sample. It decreased up to 1.6 for the samples under RF. The bioluminescence improves the DNA repair by photoreactivation, and there is evidence that photolyase is preferentially activated by blue/violet light. Our finding suggests that RF exposure may stimulate DNA repair by shifting the emission spectra from blue/green (490 nm) to blue/violet (460 nm). VC 2012 American Institute of Physics.

Following its introduction in 1967, rifampicin has become a mainstay of therapy in the treatment of tuberculosis, leprosy and many other widespread diseases. Its potent antibacterial activity is due to specific inhibition of bacterial RNA polymerase. However, resistance to rifampicin was reported shortly after its introduction in the medical practice. Studies in the model organism Escherichia coli helped to define the molecular mechanism of rifampicin-resistance demonstrating that resistance is mostly due to chromosomal mutations in rpoB gene encoding the RNA polymerase β chain. These studies also revealed the amazing potential of the molecular genetics to elucidate the structure-function relationships in bacterial RNA polymerase. The scope of this paper is to illustrate how rifampicin-resistance has been recently exploited to better understand the regulatory mechanisms that control bacterial cell physiology and virulence, and how this information has been used to maneuver, on a global scale, gene expression in bacteria of industrial interest. In particular, we reviewed recent literature regarding: (i) the effects of rpoB mutations conferring rifampicin-resistance on transcription dynamics, bacterial fitness, physiology, metabolism and virulence; (ii) the occurrence in nature of "mutant-type" or duplicated rifampicin-resistant RNA polymerases; and (iii) the RNA polymerase genetic engineering method for strain improvement and drug discovery.

Streptomycetes are exploited for the production of a wide range of secondary metabolites, including antibiotics. Therefore, both academic and industrial research efforts are focused on enhancing production of these precious metabolites. So far, this has been mostly achieved by classical or recombinant genetic techniques, in association with process optimization for either submerged or solid state fermentation. New cultivation approaches addressing the natural mycelial growth and life cycle would allow the biosynthetic potential of filamentous strains to be much better exploited. We developed a cultivation system for antibiotic-producing microorganisms which involves electrospun organic nanofibers deposited onto agar plates or immersed in liquid media. Dense filamentous networks of branched hyphae formed by bacterial colonies were found to wrapped around the fibers. We analyzed the effects of fibers on growth and antibiotic production in Streptomyces lividans, and found that the actinorhodin, undecylprodigiosin and calcium dependent antibiotic productions were positively modulated, with a two-to sixfold enhancement compared to standard culture conditions. Highlighting the secondary metabolism-promoting role of nanofibers in bacterial cultures, these results open a route to the design of improved culture systems for microorganisms based on organic nanostructures.

We have previously shown that during the late stages of the infectious process serogroup B meningococci (MenB) are able to escape the phagosome of in vitro-infected human epithelial cells. Then, they multiply in the cytosolic environment and spread intracellularly and to surrounding cells by exploiting the microtubule cytoskeleton as suggested by results of infections in the presence of microtubule inhibitors and the evidence of "nanotubes" connecting neighboring cells. In this study, by using microtubule binding assays with purified microtubule "asters" and "bundles" and microtubule "bundles" synthesized in vitro we demonstrate that the MenB capsule directly mediates the interaction between bacteria and microtubules. The direct interaction between the microtubules and the MenB capsular polysaccharide was confirmed by co-immunoprecipitation experiments. Unexpectedly, serogroup C meningococci (MenC), which have a capsular polysaccharide that differs from that of MenB only by its anomeric linkage, α(2→9) instead of α(2→8), were not able to interact with the microtubules, and the lack of interaction was not due to capsular polysaccharide O-acetylation that takes place in most of MenC strains but not in MenB. Moreover, we demonstrate that the MenB capsular polysaccharide inhibits tubulin polymerization in vitro. Thus, at variance with MenC, MenB may interfere with microtubule dynamics during cell infection.

Wheat (Triticum spp. L.), rye (Secale cereal L.), and barley (Hordeum vulgare L.) seeds contain peptides toxic to celiac patients. Maize (Zea mays L.) and rice (Oryza sativa L.) are distant relatives of wheat as well as sorghum (Sorghum bicolor (L.) Moench) and are known to be safe for celiacs. Both immunochemical studies and in vitro and in vivo challenge of wheat-free sorghum food products support this conclusion, although molecular evidence is missing. The goal of the present study was to provide biochemical and genetic evidence that sorghum is safe for celiac patients. In silico analysis of the recently published sorghum genome predicts that sorghum does not contain peptides that are toxic for celiac patients. Aqueous/alcohol-soluble prolamins (kafirins) from different sorghum varieties, including pure lines and hybrids, were evaluated by SDS-PAGE and HPLC analyses as well as an established enzyme-linked immunosorbent assay (ELISA) based on the R5 antibody. These analyses provide molecular evidence for the absence of toxic gliadin-like peptides in sorghum, confirming that sorghum can be definitively considered safe for consumption by people with celiac disease.

Understanding the mechanisms underlying the complex seaweed-bacteria associations in nature may provide information on the fitness of an invasive host. This may require the use of different approaches. In this study, we employed, for the first time, the Biolog system-Ecoplates™ to analyze the functional diversity of the culturable fraction of the bacterial assemblages associated with the surface of Caulerpa cylindracea, the invasive seaweed of the Mediterranean Sea. Seaweed samples were collected at five sites across the basin. A high similarity in the bacterial activity, expressed as Average Well Color Development (AWCD), among the study sites was observed. Culturable heterotrophic bacteria at 22 °C showed mean values ranging from 1.4 × 10(5) CFU g(-1) at Porto Cesareo (Ionian Sea, Italy) to 5.8 × 10(6) CFU g(-1) at Othonoi, Diapontine Island (Ionian Sea, Greece). The analysis of the DNA sequences on isolated bacteria demonstrated that the genera Shewanella, Marinobacter, Vibrio, Granulosicoccus and the family Rhodobacteraceae are consistently present on C. cylindracea, irrespective of its geographical origin. The present study provided new insights into the complex association between bacteria and this algal species, suggesting a specific composition and function of the associated culturable bacteria across the basin.

Abstract: Strain SPC-1T was isolated from the phyllosphere of Cynara cardunculus L. var. sylvestris (Lamk) Fiori (wild cardoon), a Mediterranean native plant considered the wild ancestor of the globe artichoke and cultivated cardoon. This Gram-negative, catalase-positive, oxidase-negative, non-spore-forming, rod-shaped and non-motile strain secreted copious amounts of an exopolysaccharide and formed slimy, viscous, orange-pigmented colonies and grew optimally at around pH 6.0-6.5 and 26-30°C in the presence of 0-0.5% NaCl. Phylogenetic analysis based on comparisons of 16S rRNA gene sequences demonstrated that SPC-1T clustered together with species of the genus Sphingomonas sensu strictu. The G+C content of the DNA (66.1 mol%), the presence of Q-10 as the predominant ubiquinone, sym-homospermidine as the predominant polyamine, and 2-hydroxymiristic acid (C14:0 2-OH) as the major hydroxylated fatty acid, the absence of 3-hydroxy fatty acids and the presence of sphingoglycolipid supported this taxonomical position. 16S rRNA gene sequence analysis showed that SPC-1 was most closely related to Sphingomonas hankookensis ODN7T, Sphingomonas insulae DS-28T and Sphingomonas panni C52T (98.19%, 97.91% and 97.11% similarity, respectively). However, DNA-DNA hybridization analysis did not reveal any relatedness at the species level. Further differences were apparent in biochemical traits, and fatty acid, quinone and polyamine profiles leading us to conclude that strain SPC-1T (JCM 17498; ITEM 13494) represents a new species of Sphingomonas, for which the name Sphingomonas cynarae sp. nov. is proposed. A component analysis of the exopolysaccharide (named SPC-1T EPS) suggested that it represents a novel type of sphingan containing glucose, rhamnose, mannose and galactose, while glucuronic acid, which is commonly found in sphingans, was not detected.

Spiramycin is a macrolide antibiotic and antiparasitic that is used to treat toxoplasmosis and various other infections of soft tissues. In the current study, we evaluated the effects of α-cyclodextrin, β-cyclodextrin, or methyl-β-cyclodextrin supplementation to a synthetic culture medium on biomass and spiramycin production by Streptomyces ambofaciens ATCC 23877. We found a high stimulatory effect on spiramycin production when the culture medium was supplemented with 0.5% (w/v) methyl-βcyclodextrin, whereas α-cyclodextrin or β-cyclodextrin weakly enhanced antibiotic yields. As the stimulation of antibiotic production could be because of spiramycin complexation with cyclodextrins with effects on antibiotic stability and/or efflux, we analyzed the possible formation of complexes by physical−chemical methods. The results of Job plot experiment highlighted the formation of a nonhost@guest complex methyl-β-cyclodextrin@ spiramycin I in the stoichiometric ratio of 3:1 while they excluded the formation of complex between spiramycin I and α- orβ-cyclodextrin. Fourier-transform infrared spectroscopy measurements were then carried out to characterize the methyl-β-cyclodextrin@spiramycin I complex and individuate the chemical groups involved in the binding mechanism. These findings may help to improve the spiramycin fermentation process, providing at the same time a new device for better delivery of the antibiotic at the site of infection by methyl-β-cyclodextrin complexation, as it has been well-documented for other bioactive molecules.

Vibrio harveyi is the major causal organism of vibriosis, causing potential devastation to diverse ranges of marine invertebrates over a wide geographical area. These microorganisms, however, are phenotypically diverse, and many of the isolates are also resistant to multiple antibiotics. In a previous study, we described a previously unknown association between Vibrio sp. AO1, a luminous bacterium related to the species V. harveyi, and the benthic hydrozoan Aglaophenia octodonta. In this study, we analyzed the susceptibility to antibiotics (ampicillin, streptomycin, tetracycline, or co-trimoxazole = mix of sulfamethoxazole and trimetoprim) of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host by using microcosm experiments. The results of minimum inhibitory concentration (MIC) experiments demonstrated that Vibrio sp. AO1 was highly resistant to ampicillin and streptomycin in pure culture. Nevertheless, these antibiotics, when used at sub-MIC values, significantly reduced the hydroid fluorescence. Co-trimoxazole showed the highest inhibitory effect on fluorescence of A. octodonta. However, in all treatments, the fluorescence was reduced after 48 h, but never disappeared completely around the folds along the hydrocaulus and at the base of the hydrothecae of A. octodonta when the antibiotic was used at concentration completely inhibiting growth in vitro. The apparent discrepancy between the MIC data and the fluorescence patterns may be due to either heterogeneity of the bacterial population in terms of antibiotic susceptibility or specific chemical-physical conditions of the hydroid microenvironment that may decrease the antibiotic susceptibility of the whole population. The latter hypothesis is supported by scanning electron microscope evidence for development of bacterial biofilm on the hydroid surface. On the basis of the results obtained, we infer that A. octodonta might behave as a reservoir of antibiotic multiresistant bacteria, increasing the risk of their transfer into aquaculture farms.

Mitochondria are eukaryotic organelles which contain the own genetic material and evolved from free-living Eubacteria, namely hydrogen-producing Alphaproteobacteria. Since 1965, biologists provided, by research at molecular level, evidence for the prokaryotic origins of mitochondria. However, determining the precise origins of mitochondria is challenging due to inherent difficulties in phylogenetically reconstructing ancient evolutionary events. The use of new tools to evidence the prokaryotic origin of mitochondria could be useful to gain an insight into the bacterial endosymbiotic event that resulted in the permanent acquisition of bacteria, from the ancestral cell, that through time were transformed into mitochondria. Electron microscopy has shown that both proteobacterial and yeast cells during their growth in the presence of increasing amount of tellurite resulted in dose-dependent blackening of the culture due to elemental tellurium (Te(0)) that formed large deposits either along the proteobacterial membrane or along the yeast cell wall and mitochondria. Since the mitochondrial inner membrane composition is similar to that of proteobacterial membrane, in the present work we evidenced the black tellurium deposits on both, cell wall and mitochondria of ρ(+) and respiratory deficient ρ(-) mutants of yeast. A possible role of tellurite in studying the evolutionary origins of mitochondria will be discussed.

Although several studies have investigated bacterial-algal interactions, the bacterial component has often not been identified, and the ecological role of bacterial-algal associations is still unclear. In the present study two different approaches (molecular and culture) have been used to characterize the bacterial community associated with the invasive alga Caulerpa cylindracea (Sonder) over time, in a coastal area of the Mediterranean basin. C. cylindracea is an invasive macroalga in the Mediterranean Sea, able to colonize several types of substrates. Traditional culture-based and PCR-SSCP methods have been used to analyze the bacterial community. Molecular traces of Gammaproteobacteria belonging to the genera Shewanella and Vibrio have been found by both approaches on the surface of C. cylindracea consistently in time, along with those of an unknown species belonging to the Rhodobacteraceae family. Other taxa belonging to Bacillus, Pseudoalteromonas, Tropicibacter, Photobacterium, Exiguobacterium, Kocuria, Ruegeria, and Marinobacter genera have been discovered by culture-based approach. PCR-SSCP method has shown traces of an unknown species of the Bacteroidetes phylum and the Granulosicoccus genus. Our results suggest that C. cylindracea hosts a bacterial assemblage scarcely variable with time. Further studies are needed to clarify the nature of this alga-bacteria association and the potential role in the spreading of this alga using a holistic view considering the seaweed with associated bacteria as an essentially unique meta-organism.

In contrast to the widely accepted consensus of the existence of a single RNA polymerase in bacteria, several actinomycetes have been recently shown to possess two forms of RNA polymerases due the to co-existence of two rpoB paralogs in their genome. However, the biological significance of the rpoB duplication is obscure. In this study we have determined the genome sequence of the lipoglycopeptide antibiotic A40926 producer Nonomuraea gerenzanensis ATCC 39727, an actinomycete with a large genome and two rpoB genes, i.e. rpoB(S) (the wild-type gene) and rpoB(R) (the mutant-type gene). We next analyzed the transcriptional and metabolite profiles in the wild-type gene and in two derivative strains over-expressing either rpoB(R) or a mutated form of this gene to explore the physiological role and biotechnological potential of the "mutant-type" RNA polymerase. We show that rpoB(R) controls antibiotic production and a wide range of metabolic adaptive behaviors in response to environmental pH. This may give interesting perspectives also with regard to biotechnological applications.

A comparative analysis of terminal respiratory enzymes has been performed on four strains of Bacillus clausii used for preparation of a European probiotic. These four strains originated most probably from a common ancestor through early selection of stable clones for industrial propagation. They exhibit a low level of intra-specific diversity and a high degree of genomic conservation, making them an attractive model to study the different bioenergetics behaviors of alkaliphilic bacilli. The analysis of the different bioenergetics responses has been carried out revealing striking differences among the strains. Two out of the four strains have shown a functional redundancy of the terminal part of the respiratory chain. The biochemical data correlate with the expression level of the mRNA of cytochrome c oxidase and quinol oxidase genes (heme-copper type). The consequences of these different bioenergetics behaviors are also discussed.

Neurotrophins are a family of proteins that are important for neuronal development, neuronal survival and neuronal functions. Neurotrophins exert their role by binding to their receptors, the Trk family of receptor tyrosine kinases (TrkA, TrkB, and TrkC) and p75NTR, a member of the tumor necrosis factor (TNF) receptor superfamily. Binding of neurotrophins to receptors triggers a complex series of signal transduction events, which are able to induce neuronal differentiation but are also responsible for neuronal maintenance and neuronal functions. Rab proteins are small GTPases localized to the cytosolic surface of specific intracellular compartments and are involved in controlling vesicular transport. Rab proteins, acting as master regulators of the membrane trafficking network, play a central role in both trafficking and signaling pathways of neurotrophin receptors. Axonal transport represents the Achilles' heel of neurons, due to the long-range distance that molecules, organelles and, in particular, neurotrophin-receptor complexes have to cover. Indeed, alterations of axonal transport and, specifically, of axonal trafficking of neurotrophin receptors are responsible for several human neurodegenerative diseases, such as Huntington's disease, Alzheimer's disease, amyotrophic lateral sclerosis and some forms of Charcot-Marie-Tooth disease. In this review, we will discuss the link between Rab proteins and neurotrophin receptor trafficking and their influence on downstream signaling pathways.

Bacteria undergoing environmental effects is extremely interesting for structural, mechanistic, and evolutionary implications. Luminescent bacteria that have evolved in a specific ambient have developed particular responses and their behavior can give us new suggestions on the task and production of luciferina proteins. To analyze the UV interaction under controlled laboratory conditions, we used photoluminescent bacterial strains belonging to a new species evolutionarily close to Vibrio harveyi sampled from a coastal cave with a high radon content that generates ionizing radiation. The survival of the bacterial strains was analyzed, in the light and in the dark, following a variety of genotoxic treatments including UV radiation exposure. The strains were irradiated by a germicide lamp. The results demonstrated that most of the strains exhibited a low rate of survival after the UV exposure. After irradiation by visible light following the UV exposure, all strains showed a high capability of photoreactivation when grown. This capability was quite unexpected because these bacteria were sampled from a dark ambient without UV radiation. This leads us to hypothesize that the photoreactivation in these bacteria might have been evolved to repair DNA lesions also induced by different radiation sources other than UV (e.g., x-ray) and that the luminescent bacteria might use their own light emission to carry out the photoreactivation. The high capability of photoreactivation of these bacteria was also justified by the results of deconvolution. The deconvolution was applied to the emission spectra and it was able to show evidence of different light peaks. The presence of the visible peak could control the photolysis enzyme.

Grain sorghum [Sorghum bicolor (L.) Moench] is a gluten-free grain that is gaining attention as a food crop that can be used in the management of celiac disease. At present, sorghum is widely grown in many semiarid regions of the world. New food-grade sorghum cultivars are of particular interest in Mediterranean countries due to improved quality characteristics and gluten-free status of the grains. Until now very few studies have examined the grain yield (GYLD) and agronomic performance characteristics of food-grade sorghum hybrids in Italy. A 2 year study was conducted to evaluate the agronomic performance of eight food-grade sorghum hybrids representing different maturity classes in trials conducted in Southern Italy. The results showed wide variation in adaptation of these hybrids as measured by differences in GYLD (2.35-8.50 t ha(-1)) and other phenomorphological characteristics. Of particular interest was the fact that many of the early-flowering hybrids (e. g. SP-X303) performed better than the later-flowering hybrids (e. g. ArchX-02). These results demonstrated that flowering time of hybrid and crop cycle length are important factors to consider in selecting cultivars for production in the Mediterranean region.

Sorghum has been grown as a food crop for many centuries in Africa and Asia and it is a cereal option for celiac patients. Due to its properties as a wheat-free food, interest is increasing in cultivating sorghum in Mediterranean countries. To evaluate the agronomic characteristics of growth in the Mediterranean area, six hybrids of sorghum (Sorghum bicolor L. Moench), representing different maturity classes, were selected and tested in experimental trials for 2 years in San Bartolomeo in Galdo (BN) hill, South Italy. The results showed moderate variation in adaptation of these hybrids as measured by differences in grain yields (4.60 to 7.30 t ha-1) and other pheno-morphological traits. In particular, the hybrid SW6129W from Bolivia and the hybrid SASG05W from Argentina had grain yields higher than others tested in these trials. Our results demonstrated that selected food-grade hybrids from South America, have agronomic characteristics well-suited for cultivation in Mediterranean countries.

L’invenzione offre il vantaggio di mettere a disposizione un procedimento che consenta di incrementare la produttività di antibiotici e di altri metaboliti secondari da microorganismi. Inoltre, l’ invenzione è quello di mettere a disposizione un procedimento che consenta di incrementare la produttività di antibiotici e di altri metaboliti secondari da microrganismi in modo rapido, semplice ed economico. Sempre scopo dell’invenzione è quello di mettere a disposizione un procedimento che consenta l’impiego di adatte matrici strutturali in grado di arricchire i sistemi di coltivazione tradizionali 10 per microrganismi produttori di antibiotici. Ancora scopo dell’invenzione è quello di mettere a disposizione un procedimento per la crescita e per l’incremento di produttività di selezionati microrganismi che sia caratterizzato da elevate rese finali.