ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04446.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04447.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A.O. EJIOFOR AND N. OKAFOR. 1991.Bacillus thuringiensisserotype H‐14 spores and crystals, produced in 5 1 fermenters, were centrifuged and resuspended in emulsified palm olein to give 3.2 × 1011colony forming units (cfu)/ml. The suspension was mixed with a cassava—molasses—palm olein—charcoal (CMPC‐2) mixture which served as the carrier, adhesive, dispersant and protectant. The final concentration of the formulation was 3.2 × 109cfu/ml. The lethal concentrations capable of killing 50% of the test population (LC50) of CMPC‐2 during 0, 1 and 2 years of storage at 32 ± 4.C were 0.056, 0.058 and 0.058 mg/ml respectively as against 0.054, 0.051 and 0.054 mg/ml for the Institut Pasteur Standard—1978 (IPS‐78) during the corresponding period. The2tests showed that the results were homogeneous atP= 0.05. The relative potencies of the preparation were 964.3, 879.3 and 931 International toxic units (ITU)Aedes aegyptias compared with the 1000 ITU assigned to IPS‐78. At 95% confidence limits there was no significant difference between the potencies of CMPC‐2 and IPS‐78. Field tests showed that CMPC‐2 provided between 87.5 and 100% control of natural populations ofAedesspp. andCutexspp. Sedimentation tests showed that CMPC‐2 settled markedly during storage. This, therefore, required that the product be

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04448.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

D.V. SINGH. A.K. TRIPATHI AND H.D. KUMAR. 1991. Sodium chloride, up to 20 mmol/l concentration, had a positive effect on acetylene reducing activity and photosynthetic oxygen evolution of a paddy field cyanobacterium,Anabaena doliolum.Beyond 20 mmol/l level of salinity adverse effects appeared. A mutant resistant to 200 mmol/l NaCl was isolated by nitrosoguanidine mutagenesis. The mutant, NaCl‐R200, showed about 20–25% more nitrogenase activity and photosynthetic oxygen evolution than the parent. Better capacity of nitrogen fixation and photosynthesis possibly could help the mutant in synthesis of osmotic stabilizer to resist the salinity str

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04449.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

B. VAN RENTERGHEM, F. HUYSMAN, R. RYGOLE AND W. VERSTRAETE. 1991. The sensitivity of four different enrichment procedures to detectListeria monocytogenesin the presence of high levels ofStreptococcus faecaliswas investigated. Defined mixed cultures ofStrep. faecalisandL. monocytogenesgave better results with one‐stage enrichment techniques. For manure samples, however, two‐stage enrichment techniques gave the best performance. The so‐called cold enrichment techniques were found to be unsatisfactory for samples from natural environments. The following materials were examined for the presence ofL. monocytogenes:fresh pig faeces (16% positive), fresh cattle faeces (20% positive), stored liquid manure (0% positive), manured soil samples (0% positive) and ground water samples (5% positive). After 3 weeks of storageL. monocytogenescould be detected in only one of the initially nine positive fresh facces samples. Two months after inoculation of stored liquid pig manure, stored liquid cattle manure and soil withL. monocytogenes, this bacterium could not be traced in any of these materials. Radishes (Raphanus sativus) and carrots (Daucus carota), sown in soil inoculated withL. monocytogenes, were gathered after 3 months and examined for the presence ofL. monocytogenes.Three of six radish samples were found to be positive. Remarkably, however, all carrot samples (six) were free ofL. monocyto

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04450.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

D.S. JONES, S.P. GORMAN, D.F. MCCAFFERTY AND A.D. WOOLFSON. 1991. The effects of three non‐antibiotic, antimicrobial agents (taurolidine, chlorhexidine acetate and providone‐iodine) on the surface hydrophobicity of the clinical strainsEscherichia coli, Staphylococcus saprophyticus, Staphylococcus epidermidisandCandida albicanswere examined. Three recognized techniques for hydrophobicity measurements, Bacterial Adherence to Hydrocarbons (BATH), the Salt Aggregation Test (SAT) and Hydrophobic Interaction Chromatography (HIC) were compared. At concentrations reported to interfere with microbial‐epithelial cell adherence, all three agents altered the cell surface hydrophobicity. However, these effects failed to exhibit a uniform relationship. Generally, taurolidine and povidone‐iodine treatments decreased the hydrophobicity of the strains examined whereas chlorhexidine acetate effects depended upon the micro‐organism treated. Subsequently, the exact contribution of altered cell surface hydrophobicity to the reported microbial anti‐adherence effects is unclear. Comparison of the three techniques revealed a better correlation between the results obtained with the BATH test and HIC than the results obtained with the BATH and SAT or SAT and HIC. However, these differences may be due to the inaccuracy associated with the visual assessment of results employed

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04451.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

M.L. LEMOS. C.P. DOPAZO, ALICIA E. TORANZO AND J. L. BARJA. 1991. Competitive relationships between antibiotic‐producing marine bacteria and other non‐producers were studied in seawater mixed cultures. Producer strains showed a competitive advantage against non‐producers as the latter were inhibited after a short time. Inhibition was also noted in mixed cultures of two producer strains. The inhibitory effect was not observed in a mixed culture with two non‐producers, which indicates that an amensalist interaction occurred between populations of antibiotic‐producing and non‐producing marine bacteria. The results suggest that antibiotics could play an important role in the competitive relationships between marine bacterial

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04452.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

M. RACINE, J. DUMONT, C.P. CHAMPAGNE AND A. MORIN. 1991. The effects of lactose, ammonium and phosphate on the production of extracellular polysaccharide fromPropionibacterium acidi‐propioniciVM‐25 were studied in whey‐based media. The polysaccharide was composed of a water‐soluble fraction (15% w/w), a water‐insoluble fraction (27% w/w) andca65% (w/w) of ash. Up to 15 g/l of polysaccharide was produced during growth on partially deproteinated whey, supplemented with lactose, NH4Cl and KH2PO4, after incubation at pH 7.0 and 25.C for 90 h. The final viscosity of the medium remained under 20 centipoises at the end of the fermentation (100–140 h). The fermentation of whey enabled a reduction of the lactose content up to 50%. The polysaccharide‐containing fractions were composed of glucose, galactose, mannose, rhamnose and fucose and had M,<5800. The polysaccharide may have applications as a low viscosity stab

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04453.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

S.B. AL‐MASAUDI, M.J. DAY AND A.D. RUSSELL. 1991. The effects of some antibiotics and biocides on the conjugative transfer of theStaphylococcus aureusgentamicin resistance plasmid pWG613 were investigated. Gentamicin and vancomycin were found to stimulate plasmid transfer frequency by 10‐ to 20‐fold whereas methicillin and three inhibitors of protein synthesis each reduced it by various degrees. Most significantly, mupirocin inhibited plasmid transfer frequency by more than 1000‐fold. All the biocides tested (cationic agents, sodium dodecyl sulphate and an organomercurial) reduced plasmid t

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04454.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

N.D. BENBOUZID‐ROLLET, M. CONTE, J. GUEZENNEC AND D. PRIEUR. 1991. In an aerobic bulk environment sulphate‐reducing bacteria (SRB) can find suitable growth conditions on surfaces where other micro‐organisms have developed an extensive biofilm. On metal surfaces they may induce or enhance corrosion. A laboratory tubular flow system was designed to study this phenomenon by creating a biofilm on stainless steel under dynamic conditions withVibrio natriegensandDesulfovibrio vulgaris.The sulphate reducer colonized the surface, constituting approximately 5% of the total population. Itsin situgrowth rate, calculated by a simplified mathematical model, showed that the attached SRB multiplied at their settling locations. No significant difference with respect to corrosion enhancement was found in the electrochemical reactions of the metal betwen the control and the reactor, whereD. vulgariswas present in the bi

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1991.tb04455.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY