Bacteriocins are ribosomally synthesized antibacterial peptides produced by bacteria that inhibit the growth of similar or closely related bacterial strains. A number of bacteriocins from a wide variety of bacteria have been discovered, and their diverse structures have been reported. Growing evidence suggests that bacteriocins have diverse structures, modes of action, mechanisms of biosynthesis and self-immunity, and gene regulation. Bacteriocins are considered as an attractive compound in food and pharmaceutical industries to prevent food spoilage and pathogenic bacterial growth. Furthermore, elucidation of their biosynthesis has led to the use of bacteriocin-controlled gene-expression systems and the biosynthetic enzymes of lantibiotics, a class of bacteriocins, as tools to design novel peptides. In this review, we summarize and discuss currently known information on bacteriocins produced by Gram-positive bacteria and their applications.

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  The anti-influenza virus activity of fossilized marine coral powder (sango mineral powder, SMP) was studied. SMP is composed in terms of mass of around 25 % of calcium and 10 % of magnesium, respectively, principally as dolomite (CaMg(CO₃)₂) but not as calcium oxide (CaO) or magnesium oxide (MgO). By mixing the influenza virus with SMP, the infectivity of the virus substantially decreased and there was more than a 10⁴ reduction on the 3rd d of infection. The antiviral effect was observed against all the type A and B strains of the influenza virus examined including the H1N1 2009 pandemic and H5N1 avian viruses. The surface structure of SMP was highly porous and the anti-influenza activity was explained by the adsorption of the viral particles onto its surface. The binding of viruses to SMP was strong and stable in the physiological condition, and the attached viruses detached only in the presence of a high concentration of phosphate. This was similar to the binding of protein to hydroxyapatite, suggesting an ionic interaction between SMP and the viral proteins. SMP maintained its activity to capture influenza viruses even after being immobilized on a non-woven textile. SMP would be useful as a practical anti-influenza tool especially in preparation for the next pandemic virus.

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  The antimicrobial activity, toxicity and antimicrobial mechanism of a new type of tris(4-alkylphenyl)sulfonium which has sterically bulky alkyl substituents (bTAPS), were estimated and compared with those of other sulfoniums which we reported previously. Concerning tris {4-(iso-propyl)phenyl}sulfonium (bTAPS-iso3) and tris{4-(tert-butyl)phenyl}sulfonium (bTAPS-tert4), the antimicrobial activity of these compounds tended to be lower than both tri(n-alkyl)sulfoniums (TASs) and tris{4-(n-alkylphenyl)}sulfoniums (TAPSs) at similar ClogP values. However, the activities of tris{4-(cyclohexyl)phenyl}sulfonium (bTAPS-cyclo6) were clearly higher than those of TAS and were almost similar to those of TAPS at similar ClogP values. The mutagenicities of tested bTAPSs were judged to be all negative. Both the acute oral toxicity strength and the acute skin irritation/corrosion toxicity strength tended to follow the order of TAPSs > bTAPSs > TASs. However, only the acute skin irritation/corrosion toxicity strength of bTAPS-cyclo6 was almost as low as that of TAS which has a similar ClogP value to bTAPS-cyclo6. Because bTAPS-cyclo6 has both high antimicrobial activity and low toxicity, this compound might become to be an alternative antimicrobial compound to relatively hazardous antimicrobials which have been widely used in many fields.

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  We found that an additive for a resin, which was comprised of collagen and aluminum (Al), showed a strong and stable antibacterial effect against various bacterium under certain conditions. We tried to clarify its mechanism of action, and investigated optimum conditions for its effects. This additive (Al cross-linked collagen powder: Al-COL) absorbed phosphorus in LB medium, gradually released aluminum in the phosphorus-reduced LB medium, and exhibited a bactericidal effect. Allophane was very suitable as the control subject, because it did not release Al in the medium, decreased phosphorus levels in the medium, and the phosphorus decrease led to a reduction in bacterial growth, though not to a bactericidal effect. On the other hand, the addition of Al to the phosphorus-reduced solution led to a bactericidal effect. These results suggested that Al can exert a strong antibacterial effect in the absence of phosphorus. This phenomenon was confirmed using film-shaped test items mixed with Al-COL powder. Furthermore, the reduction of phosphorus also synergistically led to the enhancement of the antibacterial effect of silver (Ag). The phosphorous absorption promoted the antibacterial action of Al and Ag, and Al, which has seldom been used as an antimicrobial agent, is available as an antibacterial agent in the absence of phosphorus.

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  We investigated the virucidal activity of commercially available alcohol-based hand rub products against coxsackievirus A7, B5, feline calicivirus F9, and human adenovirus type 3, type 7, type 8 using susceptible cell lines, Vero cells, CRFK cells, and A549 cells. Fifteen tested hand rub products were ethanol (EtOH) for disinfection (Japanese Pharmacopoeia Grade), two EtOH-based products, one povidone iode-containing product, one alkyldiaminoethylglycine hydrochloride-containing product, six benzalkonium chloride (BAK)-containing products, and four chlorohexidine gluconate (CHG)-containing products. Some active ingredients (BAK, benzetonium chloride, and CHG) were diluted with EtOH to make 0.5% and 0.2% solutions. Virus inactivation rates were calculated after contact with each hand rub product for 10 or 60 seconds. Of the hand rub products tested, only the povidone iode-based product showed antiviral activity superior to that of EtOH against all the strains. EtOH solutions of active ingredients (0.2% and 0.5%) also showed decreased antiviral activity. In conclusion, antiviral activity of all the commercially available alcohol-based hand rub products except that containing povidone idode was dependent on their active ingredients. The povidone idode-containing hand rub product kept its effectiveness even after the dilution with EtOH. Although alcohol-based hand rub products are convenient and suitable for the control of some microbes, they are not generally recommended for the control of viral infections.

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  The bacterial communities associated with rotifers (Brachionus plicatilis sp. complex) and their culture water were determined using culture-dependent and -independent methods (16S rRNA gene clone library). The bacterial communities determined by the culture-independent method were more diverse than those determined by the culture-dependent method. Although the culture-dependent method indicated the bacterial community of rotifers was relatively similar to that of the culture water, 16S rRNA gene clone library analyses revealed a great difference between the two microbiotas. Our results suggest that most bacteria associated with rotifers are not easily cultured using conventional methods, and that the microbiota of rotifers do not correspond with that of the culture water completely.

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