Starter culture, temperature, and antibiotic residue in fermentation of mastitic milk to feed dairy calves.
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Spiramycin fermentation residues (SFR) are hazardous wastes enriched with residual antibiotics, yet they can serve as potential feedstocks for resource recovery after appropriate treatment. In this study, SFR-derived biochar (SFR-BC) was produced by pyrolysis and applied to agricultural soil to evaluate its effects on soil properties, microbial communities, potential pathogenic bacteria, antibiotic resistance genes (ARGs), and mobile genetic elements (MGEs). A 60-day soil incubation experiment was conducted with one control and three SFR-BC application rates of 0.5%, 1.0%, and 2.0%. SFR-BC improved soil physicochemical properties, nutrient status, enzyme activities, and microbial alpha diversity. Metagenomic analysis showed that SFR-BC altered the abundance of functional genes associated with carbon and nitrogen cycling, indicating shifts in microbial functional potential. SFR-BC also changed bacterial co-occurrence patterns, with the high-dose treatment showing a more complex and highly connected network structure during incubation. In addition, high-dose SFR-BC reduced several potential pathogenic bacteria, including major plant pathogenic taxa. SFR-BC decreased soil ARG abundance by 9.38%-33.67% and MGE abundance by 6.49%-27.89% relative to the control, showing a dose-dependent reduction in antibiotic resistance-related genetic elements. Network and PLS-PM analyses further indicated that ARG variation was statistically associated with soil physicochemical properties, microbial diversity, potential bacterial hosts, and MGEs. Overall, these results suggest that SFR-BC can improve short-term soil nutrient status and reduce ARGs, MGEs, and several potential pathogenic taxa under controlled incubation conditions, providing useful evidence for the potential valorization of antibiotic fermentation residues through pyrolysis.
Pholipomycin is a new member of the phosphoglycolipid family of antibiotics. Taxonomic studies of the producing organism revealed that it has morphologically characteristic aerial mycelia in which two to three spores are borne usually on short and clavate side branches. The species name, Streptomyces lividoclavatus, has been proposed. Pholipomycin is produced mainly in the solid residue of the fermentation culture broth and is isolated by methanol extraction of the mycelial cake followed by purification on ion-exchange resin and silica gel chromatography.
Streptomyces griseolus produces a complex of antifungal nucleoside antibiotics that contain an ornithine residue linked to the ribose moiety of adenosine. 14C-Labeled compounds were added to cultures of S. griseolus (approximately 0.5 muCi/ml culture broth) and the amount of label incorporated into the two major antifungal components (sinefungin and factor C) was measured. Substantial incorporation (16 approximately 52%) was obtained with adenosine [8-14C], ATP [14C(u)], adenine [8-14C], L-ornithine [14C(u)], and DL-citrulline [5-14C]. Glycine glucose L-arginine, and acetate were incorporated to the extent of 1.7 approximately 4.7%. Studies were conducted on the fermentation time course and on the time dependence of label incorporation in order to optimize the incorporation of labeled adenine into sinefungin. Adenine [8-14C] incorporation and sinefungin specific activity were highest 48 hours after label addition and both declined during subsequent incubation. As much as 43% of the labeled adenine was incorporated into the antibiotic and sinefungin was produced with a specific activity of 24.8 muCi/mg. The labeling experiments suggest that a performed adenine derivative (e.g., an adenine nucleotide) and ornithine (or a closely related metabolite) are direct biosynthetic precursors of sinefungin.
Nosiheptic is determined in fermentation broths of Streptomyces actuosus either by a microbiological method using Staphylococcus aureus or, more easily, by an automated colorimetric method. The results obtained with both methods correspond well for concentrations greater than 100 microgram/mL with a standard deviation of 1-3%. For determination of nosiheptide as a feed additive, the microbiological assay is made more specific by pretreatment with petroleum ether and 1N HCl. Standard deviation is less than 4%, and the assay is sensitive to 1 ppm. Nosiheptide is identified in feed containing other frequently used antibiotics by thin layer chromatography with bioautography; sensitivity is 1 ppm. The absence of traces of nosiheptide in tissues of treated swine and broiler is confirmed by microbiological diffusion, sensitive to 0.025 ppm.
A new antitumor and antiviral substance, KS-2, was prepared by ethanol precipitation of the hot water extract of culture mycelia of Lentinus edodes KSLE 007. It was further purified by ECTEOLA-cellulose and Sephadex G-100 column chromatography based on the interferon-inducing activity. Its homogeneity was revealed by CsCl density gradient centrifugation, electrophoresis on cellulose acetate and Sephadex G-100 and ECTEOLA-cellulose column chromatography. KS-2 is mainly composed of alpha-linked mannose and contains a small amount of peptide which consists of serine, threonine and alanine with residual amounts of the other amino acids. The estimated molecular weight of KS-2 is between 6.0 X 10(4) and 9.5 X 10(4). KS-2 suppressed the growth of EHRLICH as well as Sarcoma-180 tumors in mice when given either orally or intraperitoneally. It is also capable of inducing an interferon in mice when dosed orally or intraperitoneally. The acute LD50 of KS-2 was found to be extremely low, more than 12,500 mg/kg when administered orally to mice.
Beagle dogs were fed a diet containing 0, 2, or 10 mug of dihydrostreptomycin (DSM) per g of feed. The 2-mug/g level was selected to represent a residue level of the antibiotic. In both treatment groups, medicated feed resulted in a shift from a predominantly streptomycin (SM)-susceptible coliform fecal population to an SM-resistant population. The proportion of resistant organisms was significant (P < 0.01) for both treatment groups. A definitive response did not occur with animals maintained on DSM-free diets. An increase in the prevalence of DSM-resistant organisms was observed after 15 days of DSM-supplemented feeding and persisted during the posttreatment phase of the study. The predominant pattern of resistance was SM-sulfamethoxypyridazine. Fifty-nine percent of SM-resistant strains transferred resistant determinants by conjugation to Escherichia coli K-12 recipients.