摘要:

AbstractThe effect of continuous‐wave ultrasound on the viability ofEscherichia coliHB101 was assessed using a 20 kHz ultrasonic processor. A standardised cell suspension of fixed concentration was used to investigate the influence of different physical and environmental conditions on ultrasound susceptibility. Cell viability decreased exponentially with time at different intensities of ultrasound. Increasing intensity caused a decrease in decimal reduction times. Loss of cell viability occurred primarily from the mechanical effects of ultrasound rather than free radical damage.E. colisusceptibility was also shown to vary with growth conditions, whereby cells cultivated either on agar or harvested from the stationary phase of liquid culture were significantly more susceptible to ultrasound than an equivalent population obtained from the exponential phase of liquid growth. The implication of these results is discussed in relation to the use of ultrasound as a novel means of bacterial transformatio

ISSN:0233-111X    

DOI:10.1002/jobm.3620360102

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620360103

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

摘要:

AbstractThe ability of a range of actinomycetes to decolorise the polymeric dye Poly R was investigated. Three well characterised lignocellulose‐degrading actinomycetes,Streptomyces viridosporus, Streptomyces badiusandThermomonospora mesophilawere found to be the most efficient at decolorising Poly R, with a maximum decolorisation rate of 0.10 unit per day. Extracellular fractions taken fromS. viridosporusgrown on a variety lignocellulose‐related substrates were also capable of decolorising Poly R, indicating that dye decolorisation was not merely due to biomass uptake. The activity of extracellular fractions from straw‐grown cultures ofS. viridosporuswas three to six times greater than those from other substrates examined. Purification of this dye‐decolorising activity fromS. viridosporususing anion exchange chromatography revealed the presence of a single active fraction. This was confirmed using gel permeation chromatography which estimated the molecular mass of the decolorising protein to be approximately 3

ISSN:0233-111X    

DOI:10.1002/jobm.3620360104

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

摘要:

AbstractDioxolides, a novel class of secondary metabolites were detected by a HPLC‐diode array screening technique in the culture filtrate ofStreptomyces tendaeTü 4042. The compounds show no biological activity against Gram‐positive and Gram‐negative bacteria, yeasts and fungi. Besides dioxolides, which consist of an unusual substituted dioxolane ring, anhydroshikimate andpara‐hydrobenzamide were detected by this technique. Both compounds were not yet described as natural

ISSN:0233-111X    

DOI:10.1002/jobm.3620360105

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620360106

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

摘要:

AbstractFactors affecting the β‐galactosidase production byPenicillium notatum1 were studied using fermentation media of different chemical composition. The medium containing lactose, salts, peptone and yeast extract with intitial pH 2.5 was selected as the best for enzyme production. Monobasic ammonium phosphate (0.9%) was found to be the best inorganic nitrogen source for lactase production. Various extraction media and metabolic inhibitors were examined for effective releasing of β‐galactosidase from the fungal cells. Using a simple method of mycelium extraction with 0.1 Triton X‐100, it was possible to obtain about 4‐fold higher amounts of enzyme in the cell free extracts, than those excreted into the post‐cul

ISSN:0233-111X    

DOI:10.1002/jobm.3620360107

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

摘要:

AbstractNonsuppurative encephalitis in calves aged 4–12 months, cow abortion and fetal deformities were endemic in dairy farms in Taiwan in recent years. A virological investigation emphasizing on Arthpodborn virus (Arbovirus) was conducted. Total of 11 strains of Akabane virus were isolated from endemic districts between June and July of 1992. Among them, seven viruses were isolated from blood samples of 15 calves showing nervous signs. Another 4 Akabane viruses were isolated from clinically healthy calves from three of six dairy farms investigated. All the six investigated farms had a recent history of abortion and fetal deformities. The isolates caused prominent cytopathic effects in HmLu‐1 cells and could reach a high virus titers (5 × 106TCID50/ml). As demonstrated by a cross neutralization test, the isolates had identical antigenicity to Iriki strain of Akabane virus, but were antigenically more distant to JaGar‐39 and OBE‐1 strain of Akabane virus. This is the first report on the isolation of Akabene virus in Taiwan, and also the second report on the isolation of Iriki virus in t

ISSN:0233-111X    

DOI:10.1002/jobm.3620360108

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620360109

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

摘要:

AbstractThe microbiological status of chicken carcases sampled at three different processing points in a South African Grade B poultry abattoir slaughtering ca. 750 birds per hour, was determined. Six skin samples and two meat samples were aseptically collected from different sites on each carcase. Total bacterial counts were performed at 25 °C, 37 °C and 43 °C and all colonies from plates showing between 30 and 300 cfu were characterised. Bacterial counts of the skin samples at 37 °C were consistently the highest, followed by those at 25 °C and then 43°, but for the two meat samples the highest bacterial counts were found at 37 °C and the lowest at 25 °C. Neck skin counts were marginally higher than bacterial counts of the other skin samples. The Gram negative generaEscherichiaandAcinetobacterwere isolated most frequently at all three incubation temperatures and from all sampling sites, while the dominant Gram positive genera wereStaphylococcusandEnterococcus. Escherichiaisolates predominated on the skin sampling site cranio‐dorsal to the pygostyle, whilstStaphylococcusisolates predominated on the skin sampling site caudal to the breastbone. Microbiological contamination is a major problem in the abattoir studied and further studies should therefore aim to determine points of maximum contamination in the proces

ISSN:0233-111X    

DOI:10.1002/jobm.3620360110

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY

摘要:

AbstractThe mycobiota of the sandy soil of Ipanema Beach, Rio de Janeiro, Brazil, was investigated in 144 sand samples collected at four different sites along the sea coast, divided into three subsites. for a period of one year. A total of 4285 yeast colonies and of 6956 of colonies filamentous fungi were isolated using conventional media and techniques. Representatives of the filamentous fungi corresponding to a total of 1334 colonies were identified and assigned to 34 genera and 170 species. The genera of highest incidence and their respective numbers of species were as follows:Aspergillus, 30.4%, 32 spp.;Penicillium, 16.2%, 35 spp.;Fusarium, 12,6%, 33 spp.:Trichoderma, 6.4%, 7 spp.;Paecilomyces, 3.7%, 10 spp.:Cladosporium, 3.1 %, 8 spp. andAcremonium, 1.0%, 8 spp. Several other genera and species were detected at quite low occurrences. Non‐sporulating fungi (18.3%) and Coelomycetes (Sphaeropsidales) (1.9%) were also detected. Most of the genera detected belonged to theDeuteroycotina, with fewer proportions belonging to theAscomycotinaandZygomycotina.Moniliaceaewas represented by the largest number of species andDematiaceaewas represented by the largest number of genera. In terms of seasonal distribution, the largest number of filamentous fungi was isolated during the winter and the smallest number the Summe

ISSN:0233-111X    

DOI:10.1002/jobm.3620360111

出版商:Wiley‐VCH    

年代:1996

数据来源: WILEY