β‐Lactam and aminoglycoside production from streptomycetes

Streptomycin resistant streptomycetes were isolated from four diverse sites. Two sites in Germany were sampled and included an agricultural experimental plot of apple trees which had a history of streptomycin application (AR) and a control site without antibiotic application (CR). Two sites in the UK were sampled; a pastureland site which had sewage injection (DW) and an agricultural site (CW). The actinomycete counts indicated a high proportion of streptomycin resistant isolates in the CW soil. Streptomycetes were identified by partial sequencing of the 16S rDNA. PCR product of the hypervariable gamma region of 16S rDNA allowed analysis by denaturing gradient gel electrophoresis to assess the diversity within the isolates. The streptomycin and sewage sludge treated sites showed decreased diversity within streptomycete populations. Isolates were screened for the streptomycin resistance gene, strA, and flanking biosynthesis gene, strB1. Distribution of these genes indicated the prevalence of str genes in the streptomycin treated soil. Evidence of horizontal gene transfer was recorded in isolates identified as Streptomyces platensis recovered from CR and AR sites which had acquired a streptomycin resistance gene homologous to that found in Streptomyces griseus. Members of the latter species were the most abundant streptomycin resistant streptomycetes isolated from all soils.

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“…Streptomycetes isolated from soil were streaked on streptomycin production agar medium [23]. Plates were incubated for 5 days at 30 ‡C.…”

Section: Streptomycin Production Bioassaymentioning

confidence: 99%

Distribution of streptomycin resistance and biosynthesis genes in streptomycetes recovered from different soil sites

Tolba

Egan

Kallifidas

et al. 2002

FEMS Microbiology Ecology

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“…In particular, amino acid and lipid supplementation has been recognized as an important contributor of required metabolic precursors. For example, addition of 1% L-cysteine and 1% L-valine improved beta-lactam activity 20-fold (Berwick, 1988). Supplementation with C 10 to C 18 lipids doubled the specific productivity of a thiopeptide antibiotic without the inhibitory effects of glucose .…”

Section: Introductionmentioning

confidence: 99%

Secondary metabolite scale‐up to minimize homolog impurity levels

Junker¹,

Reddy²,

Olewinski³

et al. 1998

Biotechnol. Bioeng.

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A mutant strain of Streptomyces hygroscopicus was found to produce up to 9.0 units/L of an immunoregulant precursor, immunomycin, with up to 3.5% of a lower homolog impurity under either dual fed-batch or batch conditions. Glycerol and valine were key nutrients influencing productivity and impurity levels. Soybean oil was successfully substituted for glycerol as a carbon source to minimize shot additions to batch culture. The remainder of the production medium was composed largely of defined components with the exception of yeast extract.Valine limitation increased lower homolog formation while decreasing higher homolog formation; excess valine decreased lower homolog formation below 2-3% while increasing higher homolog formation. Higher homolog formation in the presence of valine seemed to be slower than lower homolog formation in the absence of valine. Valine was believed to be the major butyrate precursor; consequently its availability influenced the impurity profile. A preliminary cost analysis suggests that elimination of added valine from the cultivation and replacement of glycerol with soybean oil can result in a 6.6-fold reduction in media costs relative to the original fed-batch process.

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“…For antibiotic production these actinomycetes were cultivated in fluid APM-medium (Berwick 1988) under aerobic conditions for 7 days at 30°C. Biochemical characterization of these strains was conducted according to the methods of Pridham & Gottlieb (1948), Perlman & O´Brien (1956), Berd (1973), Pridham & Tresner (1974), Gordon (1974) and Land (1992).…”

Section: Bacterial Strains and Culture Conditionsmentioning

confidence: 99%

Adherence and experimental infection of bacteria associated with periodontal infections of young cattle in Brazil ("Cara inchada")

Grassmann

Döbereiner²,

Dutra

et al. 1997

Pesq. Vet. Bras.

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Pesq. Vet. Bras. 17(3/4):123-125, jul./dez. 1997 123 SINOPSE.-[Aderência e infecção experimental de bactérias associadas com infecções peridentárias de bovinos jovens no Brasil ("cara inchada").] Foram realizados ensaios in vitro e in vivo para estudar o possível envolvimento de actinomicetos do solo como produtores de estreptomicina e actinomicina na pathogênese da periodontite da cara inchada dos bovinos (CI). A aderência de Bacteroides spp. às células epitheliais da gengiva marginal de bezerros, dos quais se sabe estarem associados às lesões progressivas da CI, aumentou significantivamente através a adição de estreptomicina, actinomicina ou de antibióticos produzidos pelo cultivo de actinomicetos do solo. Aplicações de Bacteroides spp. e Actinomyces pyogenes, junto com os antibióticos, na gengiva dos dentes premolares maxilares de bezerros da raça holandês preto-branco, de cerca de 1 mês de idade, não provocaram lesões progressivas da CI. Somente um bezerro mostrou leve diarréia e retração temporária da gengiva no local da aplicação.

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β‐Lactam and aminoglycoside production from streptomycetes

Cited by 9 publications

References 15 publications

Distribution of streptomycin resistance and biosynthesis genes in streptomycetes recovered from different soil sites

Distribution of streptomycin resistance and biosynthesis genes in streptomycetes recovered from different soil sites

Secondary metabolite scale‐up to minimize homolog impurity levels

Adherence and experimental infection of bacteria associated with periodontal infections of young cattle in Brazil ("Cara inchada")

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