Expression of the Lantibiotic Mersacidin in Bacillus amyloliquefaciens FZB42

Lantibiotics are small peptide antibiotics that contain the characteristic thioether amino acids lanthionine and methyllanthionine. As ribosomally synthesized peptides, lantibiotics possess biosynthetic gene clusters which contain the structural gene (lanA) as well as the other genes which are involved in lantibiotic modification (lanM, lanB, lanC, lanP), regulation (lanR, lanK), export (lanT(P)) and immunity (lanEFG). The lantibiotic mersacidin is produced by Bacillus sp. HIL Y-85,54728, which is not naturally competent

Biophysical investigation into the antibacterial action of modelin-5-NH2

Modelin-5-CONH2 (M5-NH2) is a synthetic antimicrobial peptide, which was found to show potent activity against Bacillus subtilis (Minimum lethal concentration = 8.47 µM) and to bind strongly to membranes of the organism (Kd = 10.44 µM). The peptide adopted high levels of amphiphilic α-helical structure in the presence of these membranes (> 50 %), which led to high levels of insertion (Δπ ≥ 8.0 mN m-1). M5-NH2 showed high affinity for anionic lipid (Kd = 7.46 µM) and zwitterionic lipid (Kd = 14.7 µM), which drove insertion into membranes formed from these lipids (Δπ = 11.5 and 3.5 mN m-1, respectively). Neutron diffraction studies showed that M5-NH2 inserted into B. subtilis membranes with its N-terminal residue, L16, located 5.5 Å from the membrane centre, in the acyl chain region of these membranes, and promoted a reduction in membrane thickness of circa 1.8 Å or 5 % of membrane width. Insertion into B. subtilis membranes by the peptide also promoted other effects associated with membrane thinning, including increases in membrane surface area (Cs-1 decreases) and fluidity (ΔGmix > 0 to ΔGmix 55%), and it is speculated that the antibacterial action of the peptide may involve the toroidal pore, carpet or tilted-type mechanism of membrane permeabilization

Viruses in extreme environments

The original publication is available at www.springerlink.comInternational audienceThe tolerance limits of extremophiles in term of temperature, pH, salinity, desiccation, hydrostatic pressure, radiation, anaerobiosis far exceed what can support non-extremophilic organisms. Like all other organisms, extremophiles serve as hosts for viral replication. Many lines of evidence suggest that viruses could no more be regarded as simple infectious ‘‘fragments of life'' but on the contrary as one of the major components of the biosphere. The exploration of niches with seemingly harsh life conditions as hypersaline and soda lakes, Sahara desert, polar environments or hot acid springs and deep sea hydrothermal vents, permitted to track successfully the presence of viruses. Substantial populations of double-stranded DNA virus that can reach 109 particles per milliliter were recorded. All these viral communities, with genome size ranging from 14 kb to 80 kb, seem to be genetically distinct, suggesting specific niche adaptation. Nevertheless, at this stage of the knowledge, very little is known of their origin, activity, or importance to the in situ microbial dynamics. The continuous attempts to isolate and to study viruses that thrive in extreme environments will be needed to address such questions. However, this topic appears to open a new window on an unexplored part of the viral world

Prospect and potential of Burkholderia sp. against Phytophthora capsici Leonian: a causative agent for foot rot disease of black pepper

Foot rot disease is a very destructive disease in black pepper in Malaysia. It is caused by Phytophthora capsici Leonian, which is a soilborne pathogenic protist (phylum, Oomycota) that infects aerial and subterranean structures of many host plants. This pathogen is a polycyclic, such that multiple cycles of infection and inoculum production occur in a single growing season. It is more prevalent in the tropics because of the favourable environmental conditions. The utilization of plant growth-promoting rhizobacteria (PGPR) as a biological control agent has been successfully implemented in controlling many plant pathogens. Many studies on the exploration of beneficial organisms have been carried out such as Pseudomonas fluorescens, which is one of the best examples used for the control of Fusarium wilt in tomato. Similarly, P. fluorescens is found to be an effective biocontrol agent against the foot rot disease in black pepper. Nowadays there is tremendous novel increase in the species of Burkholderia with either mutualistic or antagonistic interactions in the environment. Burkholderia sp. is an indigenous PGPR capable of producing a large number of commercially important hydrolytic enzymes and bioactive substances that promote plant growth and health; are eco-friendly, biodegradable and specific in their actions; and have a broad spectrum of antimicrobial activity in keeping down the population of phytopathogens, thus playing a great role in promoting sustainable agriculture today. Hence, in this book chapter, the potential applications of Burkholderia sp. to control foot rot disease of black pepper in Malaysia, their control mechanisms, plant growth promotion, commercial potentials and the future prospects as indigenous PGPR were discussed in relation to sustainable agriculture

Minimum Information about a Biosynthetic Gene cluster

A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit. To facilitate consistent and systematic deposition and retrieval of data on biosynthetic gene clusters, we propose the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard.Chemistry and Chemical Biolog

The Complete Genome of Bacillus amyloliquefaciens subsp. plantarum CAU B946 Contains a Gene Cluster for Nonribosomal Synthesis of Iturin A

Blom J, Rückert C, Niu B, Wang Q, Borriss R. The Complete Genome of Bacillus amyloliquefaciens subsp. plantarum CAU B946 Contains a Gene Cluster for Nonribosomal Synthesis of Iturin A. Journal of bacteriology. 2012;194(7):1845-1846.The genome of the rhizobacterium Bacillus amyloliquefaciens subsp. plantarum CAU B946 was 4.02 Mb in size and harbored 3,823 genes (coding sequences [CDS]). Nine giant gene clusters were dedicated to nonribosomal synthesis of antimicrobial compounds. Remarkably, strain CAU B946 possessed a gene cluster involved in synthesis of iturin A