Many effective anti-infective drugs have been developed from the compounds based on direct anti-infective screening programs. However, the development of anti-infective drugs has been historically restricted to a limited set of validated targets. Such a strategy caused insufficient chemical variability, which resulted in clinical resistance and the appearance of novel pathogens, promoted further by excess medication with particular drugs. Therefore, discovery of novel drugs that have new modes of action has been highly anticipated. The whole genome sequence has recently become available for many organisms. This provides an opportunity to expand the range of potential drug targets, and to change the strategy from a direct antiinfective screening program to rational target-based drug design. The application of genomebased technologies would lead to further change in the drug discovery process. In this review, their application to the drug discovery process is reviewed.
Even if a sporeformer is subjected to heat processing, in some cases it can survive in food. We focused on Bacillus, a sporeformer. We gathered 22 kinds of marketed soybeans, mixed them in equal amounts, heated them at 90°C for 5 min and made soybean milk for experiments in our laboratory. We isolated Bacillus cereus and Bacillus licheniformis from the milk and tried to identify the source of contamination. These bacteria were also isolated from 22 kinds of soybeans. Total DNA were extracted from the isolates and compared by RAPD analysis (Random Amplified Polymorphic DNA) and Southern blotting with 23S rRNA-targeted oligonucleotide probes, and RiboPrinter (R) (Qualicon). It was supposed that the B.licheniformis isolated from the product was identical to the B.licheniformisfrom one of the raw materials. Moreover, as the B.cereus of the product differed from the B.cereus present in the original soybeans at the genomic level, it appeared that the contaminants were derived from our laboratory environment. For B.licheniformis and B.cereus, we constructed a primer that was effective in RAPD analysis. The Ribotyping reported in this paper might be effective for the polymorphic analysis of B.cereus.
Ozone gas sterilization was confirmed using commercially available as well as homemade biological indicators (Bls) utilizing Geobacillus stearothermophilus (formerly it was classified as Bacillus stearothermophilus) ATCC 12980 or ATCC 7953. The relationship between the ozone gas concentration, relative humidity or temperature and decimal reduction value (D) of Bl was studied. We also investigated how the ozone gas sterilization performance was affected by the difference in the characteristics of the carrier materials of Bls. The carrier materials used were synthesized polymers with different characteristics and stainless steels (SUSs) with different levels of surface roughness and cleanness. Effect of the difference in the ATCC number of the BI on the D values was also studied. There existed a satisfactory relationship between temperature, humidity and ozone gas concentration and D value (r>0.9). Results indicated that D values from Bls with carrier materials of more hydrophilic materials were greater. In addition, the D value of the Bl with a carrier material made of SUSs was greater than that made of polymers. The difference in the roughness of the surface of the SUS material did not cause any significant difference in D values. On the contrary, the difference in the cleanness caused a difference in D values. The difference in the SUS components, i.e. Fe, Ni, may cause some differences in D values. Resistance of G. stearothermophilus ATCC 12980 was around two times greater than that of ATCC 7953 when expressed as CT (concentration X time).
The present study was performed to evaluate the efficiency of a method combining immunomagnetic separation (IMS) followed by CIN agar plating and polymerase chain reaction (PCR) for the rapid, specific and sensitive detection of pathogenic Yersinia enterocolitica. The immunomagnetic beads for Y. enterocolitica 03 or 08, prepared in this study, could sensitively and specifically capture serovar 03 or 08. Furthermore, all of pathogenic Y.enterocolitica strains could be detected by PCR with a chromosomal gene (ail) as the target. The proposed method of combining IMS-plating and PCR with ail-primer set was shown to be capable of specifically and sensitively isolating and identifying as little as 10cfu/g of pathogenic Y.enterocolitica in food and human materials within 1-2 days. In addition, the proposed method has the advantage that the bacterial colonies as living cells in the samples are available for investigating the foodborne infections.
The efficacies of gaseous ozone and sodium hypochlorite as an oxidizing agent for cleaning were compared in a laboratory model system using stainless steel particles fouled with proteins. Exposure of the protein-fouled stainless steel particles to 0.5% (v/v) gaseous ozone for 30 min enhanced the removal of the various proteins during subsequent alkali cleaning with NaOH solution to the same degree as the NaOH solution containing sodium hypochlorite at 0.2 to 0.4 g/l. The effect of ozone pretreatment on the removal of the proteins depended on the concentration of gaseous ozone. Pretreatment with a highly concentrated gaseous ozone of 20% for 30 min resulted in the almost complete removal of the proteins from stainless steel particles.
Suppressive effects of antinematodal Streptomyces spp. strain NA-369 on Meloidogyne incognita infested soil were evaluated. The NA-369 amendment, prepared by fixing the cultured NA-369 strain in paper-pulp compost, was mixed with M. incognita-infested soil before eggplant cultivation. Decreases in the gall index of eggplants and M. incognita population density in soil and increases in the fresh shoot weight and total fresh fruit weight of eggplants and the free-living nematode population density in soil were observed in the NA-369 amendment treated zone compared with the untreated control zone. As comparative controls, wettable powder including endospores of Pasteuria penetrans (Pp-powder) had no suppressive effect on M. incognita. There was no interaction or synergism between the NA-369 amendment and Pp-powder in this experiment.
Effects of high pressure gaseous carbon dioxide treatment (35°C, 6.5 MPa) (HGCT) and supercritical carbon dioxide treatment (35°C, 30 MPa) (HSCT), followed by heat treatment at 70°C (criterion for germination), on Bacillus coagulans and B. licheniformis spores were investigated. In both strains, HSCT was more effective in inactivating the bacterial spores than HGCT. Approximately 10% of the spores of B. coagulans were inactivated, and 40% of the B. coagulans spores germinated with HGCT for 120 min. Approximately 90% of the spores of B. coagulans were inactivated and germinated with HSCT for 120 min. Approximately 20% of the spores of B. licheniformis were inactivated, and 70% of the B. licheniformis spores germinated with HGCT for 120 min. Approximately 80% of the spores of B. licheniformis were inactivated, and 90% of the B. licheniformis spores germinated with HSCT at 120 min. These results suggest that the spores germinate more effectively with HSCT than HGCT, and germinated spores are more sensitive to HSCT than HGCT.