摘要:

AbstractEighty six species belonging to thirty one genera were collected from the qat phyllosphere (30 genera and 78 species) and phylloplane (20 genera and 64 species) of 24 varieties tested. In the phyllosphere the most frequent genera wereCladosporium, AspergillusandAlternariafollowed byPenicillium, Drechslera, Fusarium, Curvularia, PhomaandChaetomium.From the preceding genera the most prevalent species wereC. herbarum, C. macrocarpum, A. niger, A. flavus, A. alternata, A. phragmospora, P. citrinum, P. notatum, D. spicifera, D. halodes, D. hawaiiensis, F. oxysporum, F. moniliforme, C. lunata, P. humicola, P. herbarumandC. globosum.In the phylloplane the order of genera frequency was more or less the same, while the most common species wereC. herbarum, C. sphaerospermum, A. niger, A. flavus, A. alternataandA. tenuissima.

ISSN:0233-111X    

DOI:10.1002/jobm.3620310202

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620310203

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe incidence and severity of the Rice Yellow Mottle Virus (RYMV) was monitored in various rice environments in West Africa. Its presence or absence being determinded through symptomatology and serological tests. RYMV was found in all the rice growing environments at different levels of incidence and severity which appear to be dependent on the type of variety planted, the rice environment and the climatic factors under which the rice is cropped. RYMV has been shown to cause losses ranging from 19.5% to 95.5%. Graminaceous weeds including some wild rices have been confirmed as alternate hosts for RYMV. Twenty five rice cultivars consisting of local and locally developed cultivars showed tolerant reactions to RYMV. Most of these varieties showed stable resistance to rice blast in an earlier study. The manifestation of RYMV symptoms on the uninoculated test rice varieties indicated the possibility of the virus being transmitted either through the virus vector or might be seedborne.

ISSN:0233-111X    

DOI:10.1002/jobm.3620310204

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620310205

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe recently isolated phages ØST3 and ØST1 were compared as to their lysis behaviour in about 100 differentP. aeruginosastrains. The growth of ØST3 varies greatly in different host strains. We demonstrated one case of “non‐classical”, host‐dependent modification and restriction. Here the capability to adsorb, and consequently to reproduce in a given host strain differs, depending on which modification the phage aquired in its former host. — The DNA‐containing phage ØST1 displays stable lysis properties in the majority of the host strains. This makes ØST1 a candidate for therapeutic phage preparations. One of the reasons for stable lysis properties is the apparent selection against recognition sites of restriction enzym

ISSN:0233-111X    

DOI:10.1002/jobm.3620310206

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractFor 7 cultures of basidiomycetous wood‐decay fungi the decline of the following vitality marks were recorded over a 6‐year period: (i) Consumption of sterilized beech wood substrate within a time unit as an indicator of the overall vigorousness of the fungus, (ii) decline of the competitive saprophytic ability (kratovirulence), which enables the fungus to colonize natural nonsterile substrates, (iii) capacity for sexual reproduction, (iv) several morphological features of the fungal colony. The reference strains kept growing at + 1 … 2°C on fertilized wood dust substrate retained in 5 of 7 cases all of their juvenility marks, although the wood‐decay capacity gradually dropped back to 65 to 34% that of the initial value. The substrains maintained on liquid still cultures at 23°C lost their vitality marks after a period of continuous decline rather abruptly. With the loss of kratovirulence and fruiting capacity the strains were no longer viable under field conditions, and with the drop of the sterile wood‐decay capacity to less than 3% by dry weight the formation of aerial mycelium and melanin pigments virtually ceased. In several fungal species the colonies segregated into coexisting sectors of extreme senescence and comparative juvenility, and a spread of senescence to the juvenile sectors did not occur. It is concluded that stock cultures of wood‐decay fungi are subject to progressive senescence even under optimum conditions of strain preservation. Their current vitality should be examined in a sterile wood decay test before they are used in biotechnolog

ISSN:0233-111X    

DOI:10.1002/jobm.3620310207

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe initially juvenile stock cultures of basidiomycetous wood‐decay fungi lose most of their physiological performances during long‐term storage in axenic culture. In order to link the rapidity of this debilitation or senescence process with the properties of the fungal genome, both a juvenile strain ofBjerkandera adusta(Bjerad 2S3) and a pre‐aged strain ofHypholoma sublateritium(Ns 1) were transferred to 7 identical round flasks with a liquid still culture medium and maintained at 23°C. In a 6‐month rhythm the disappearance of several juvenility marks among the 7 isogenic subcultures was recorded and compared with the vitality status of the 2°C maintained reference strains. Within 26 to 30 months of observation, the 7 isogenic subcultures of Bjerad 2S3 as well as Ns 1 aged at a strikingly different speed. Both mycelial thalli segregated into coexisting sectors of progressive senescence and relative juvenility. The isogenic subcultures dominated by juvenile sectors displayed dramatically longer life spans than did the subcultures dominated by the senescent mycelial sectors. This means that initially isogenic parts of a mycelial thallus have a strikingly different life expectancy. In the slow‐ageing subcultures of Ns 1, neither the senescent nor the juvenile sector were able to overgrow and infect the colony of their coexisting conterpart. The preconditions are discussed that could possibly prevent the spread of the carriers of senescence into the juvenile myc

ISSN:0233-111X    

DOI:10.1002/jobm.3620310208

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractUsing the chiral methyl group methodology, the methylation step in the biosynthesis of ergot alkaloids catalyzed by the enzyme AdoMet:dimethylallyltryptophan N‐methyltransferase was found to proceed with net inversion of methyl group configuration. The enzyme thus conforms to the majority of methyltransferases studied which mediate a direct SN2 transfer of the methyl group from AdoMet2) to the acceptor nucleophile in a ternary enzyme substrate comple

ISSN:0233-111X    

DOI:10.1002/jobm.3620310209

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620310210

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractBy UV and NTG mutagenesis numerous auxotrophic, antibiotic‐resistant and melanin‐negative mutants were isolated fromStreptomyces michiganensisDSM 40 015 which proved to possess a efficient photoreactivation system. Using amel−test strain with three auxotrophic markers and a antibiotic resistance for crosses with numerous prototrophicmel−strains three classes of mutants (melA,melBandmelC) could be found. This classification was further supported by a series of crosses. ThemelClocus seemed to correspond to themelClocus ofS. glaucescenswhich contains the tyrosinase structur

ISSN:0233-111X    

DOI:10.1002/jobm.3620310211

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY