摘要:

Manuscripts should be drafted as concisely as possible. The Editors always reserve the right to require authors to reduce the length of their manuscripts if they exceed the length stated below.

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00823.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Sucrose, a non‐pectic carbon source, with yeast extract (YE) added was able to support the production of pectin lyase (PL) byPenicillium griseoroseumDierckx. However, in the absence of YE, the fungus did not produce PL but grew and caused a marked reduction in culture medium pH. Furthermore, in the absence of YE, only a culture medium with a high buffering capacity permitted the production of PL in the presence of pectin. On the other hand, in the presence of 0.06% YE and of 0.1% pectin, the fungus produced maximum growth and specific PL activity during a 48‐h period of culture, with a small variation in medium pH. In the absence of sucrose, YE concentrations from 0 to 0.6% did not support enzyme production, indicating synergism between sucrose and YE for production of the enz

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00824.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Isolates ofEmericella nidulans(7 isolates),Aspergillus egyptiacus(7) andA. versicolor(5) were tested for their ability to transform progesterone. Consistent results were obtained between isolates of the same species. WhilstA. egyptiacusandE. nidulanspossessed the enzyme system catalysing the transformation of progesterone into 11‐α‐hydroxyprogesterone,A. versicolordid not. Thus, progesterone transformation could be considered as further diagnostic evidence thatA. egyptiacusis related to theEmericellag

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00825.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Production and degradation of diacetyl by a commercialSaccharomyces cerevisiaestrain was studied. This yeast did not produce diacetyl but could consume it. Diacetyl degradation activity was biological and was present even when the yeast was grown in the absence of diacetyl. Maximum specific activity was obtained when the yeast was grown in 280 μmol of diacetyl, 1 vvm of aeration and 37°

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00826.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The intracellular pH value ofSaccharomyces cerevisiaeNCYC 1681 was measured using radiolabelled [14C]‐propionic acid. Errors, due to the binding of radioactive material to trub, were eliminated using silicone oil centrifugation. Replication of analyses reduced the variations associated with low cell counts during fermentation. Whilst fermenting brewer's wort, yeast intracellular pH values were maintained within a narrow range (5.9–6.4). Cellular ATP concentrations were highly conserved in spite of the fact that the cells were exposed to an increasing concentration of ethanol as the fermentation progres

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00827.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

In pediocin AcH producingPediococcus acidilacticistrains the genes for both the production of pediocin and immunity against it are encoded in an 8.9 kb plasmid pSMB74. Following loss of this plasmid, the variants lost the ability to produce pediocin AcH, but some retained the resistance against it. This resistance was a transient trait, acquired while nonproducing cells grew in the presence of pediocin AcH but lost when the cells were grown in the absence of it.

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00828.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Actinomycetes were isolated from 10 soil samples, three representing sediments or shoreline of a pulp mill effluent polluted marsh pond and the rest topsoil from Finnish coniferous woodland. After a preliminary screen, 32 isolates exhibiting antifungal, antibacterial or genotoxic activities were obtained. The high incidence of strains with genotoxic properties (12 in this screen) was an unexpected finding. The majority (14) of the 19 antifungal isolates produced antibiotics of polyene type.

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00829.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The effect of the carbohydrate growth substrate on polysaccharide‐degrading enzyme formation by anaerobic fungi was examined using four strains ofPiromycesisolated from hindgut fermenters, threePiromycesisolates from the pre‐peptic forestomach of macropodid marsupials, and two ruminal isolates ofNeocallimastixspp. The range of enzymes formed by the nine isolates was similar although, under the growth conditions examined, one hindgut isolate did not form amylolytic enzymes. The cellulolytic and xylanolytic enzyme profiles were the same: inter‐strain differences in the levels of enzymic activity were apparent, but they were not related to either the genus or intestinal origin of the isolates. Pectin degrading enzymes were not detected in any of the isolates. The cellulolytic and xylanolytic enzymes were formed constitutively during growth on mono‐, di‐ and polysaccharidic carbohydrates but the specific activities were both strain‐and substrate‐dependent. The activities were considerably lower in glucose‐grown preparations of three of the fungi (one each from the hindgut, foregut and rumen) indicating that enzyme synthesis was repressed by glucose; enzyme formation by the other isolates studied was not controlled by catabolite regula

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00830.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The lysis of cell wall, cell wall fractions (F1S—alkali and water soluble, F1I—alkali soluble and water insoluble, and F4—β‐chitin‐glucan) and chlamydospores ofFusarium oxysporumf.sp.lycopersicirace 2(Fol 2)with crude enzyme preparations from Mucorales(Absidia californica, Mortierella vinacea, Mucor hiemalis, Phycomyces blakesleeanus, Rhizopus stoloniferandSyncephalastrum racemosum) has been studied during an incubation period of 72 h. The lysis of the F1S fraction and chlamydospores was followed by the release of reducing substances. The lysis of the other fractions and cell walls was followed by percentage of decrease in optical density (lysis degree) and release of reducing substances. A correlation between the degradation of cell walls and cell wall fractions was observed. The soluble fraction was the most resistant to lysis by these enzymes, with the highest release of reducing substances at 4% of the material as glucose equivalent using the crude enzyme preparation fromMucor hiemalis.Crude enzyme preparations fromRhizopus stoloniferproduced the highest lysis (33.4%) and release of reducing substances (22.1%) from theFol2 cell wall. The enzymes fromM. hiemalisproduced the highest degradation of chlamydospores. A possible biological control ofFol 2with lytic enzymes fromR. stoloniferorM. hiemalisis indicated.We wish to thank Dr J. Tello for theFol 2strain, Dr P. Melgarejo for her valuable discussion and Mrs Carmelina Rodríguez for her technical assistance. This work was supported by the Spanish programmes ‘Plan Nacional de Investigación Científica y Desarrollo Tecnológico’ (AGR91‐0014‐C02‐02) and ‘Plan Nacional de Investigación de la Comunidad de Madrid’ (C052/91) and DGICYT PB92–0001. We also wish to thank Norel S.A. for their con

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00831.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Fifty‐two different varieties of sausage, salami and pâté were examined using Oxford (Oxoid) and PALCAM (Merck) listeria‐selective agars. Seven (13%) samples were positive forListeria monocytogenesand 14 (27%) samples were positive for otherListeriaspecies, while 31 (59%) samples were negative forListeriaspecies. The effectiveness of PALCAM and Oxford medium for the isolation ofL. monocytogenesfrom the meat samples was compared. PALCAM medium was consistently more effective in suppressing other micro‐organisms thus enhancing the possibility of detectingListeriaspecies present in low numbers. The isolation ofListeriaspecies for identification was also easier using PALCAM

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00832.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY