REVIEW | doi:10.20944/preprints202004.0498.v1
Subject: Life Sciences, Biotechnology Keywords: single cell protein; probiotic; actinomycetes; fermentation optimization
Online: 28 April 2020 (10:49:09 CEST)
Single cell proteins are the dead dried cells of microorganisms or purified protein isolated from microorganism’s cell culture, used as a food supplement to humans’ food and animals feed. World suffer from malnutrition particularly developing countries, due to rapid increase in population, increased the demand for protein and nutrients requirement. Bacteria is potential microorganism for SCP production due to high protein content, fast generation time, bio-active secondary metabolites production and can grow on various substrates. Actinobacteria species and strain have capability to produce biological active compounds, produced about two-thirds of antibiotics available in the market, actively used as antibiotics, antiprotozoal, antifungal, antiviral, anticancer, anticholesterol, antihelminth and immunosuppressant. Actinomycetes can be used as probiotic as well as single cell protein that will deal with antibiotic as well as protein source.
ARTICLE | doi:10.20944/preprints202208.0132.v1
Subject: Life Sciences, Microbiology Keywords: civil science; antibiotic producers screening; actinomycetes; reporter systems; chartreusin; pikromycin
Online: 8 August 2022 (05:27:03 CEST)
Since streptomycin discovery, actinomycetes were the main source for new antibiotics, but after the Golden age (1950-1960th) the discovery rate significantly decreased. The high probability to rediscover well-known antibiotics led to a reduction in interest in soil bacteria as a source for new antibiotics. At the same time, actinomycetes remain a very promising reservoir for searching for new active molecules. In this work, we present several reporters containing eye-visible fluorescent protein genes, which can be used to increase the efficiency of determining the mechanism of antibiotics at the very initial stage of screening. Presented reporters and the following pipeline were optimized given the involvement of citizen scientists without specialized skills and equipment in order to utilize the reservoir of soil bacteria in the search for new antibiotic producers. The combination of mechanism-based approaches and civil science has proved its effectiveness in practice revealing a significant increase in the screening rate. Two new strains Streptomyces sp. KB-1 and BV113 were found to produce antibiotics pikromycin and chartreusin, respectively, demonstrating the efficiency of the pipeline.
ARTICLE | doi:10.20944/preprints202207.0085.v1
Subject: Biology, Other Keywords: Crown of thorns starfish (CoTS); actinomycetes; venom extract; anti-enzymatic; antibacterial activity
Online: 6 July 2022 (04:03:02 CEST)
Crown of thorns starfish (Acanthaster planci) are coral predators with advantages of having toxicity in their venom and tissue regeneration capabilities. With all these characteristics, only a handful of studies have highlighted the association of microorganisms with this organism. Crown of thorns starfish are common in Fiji and their analyses of microbial diversity for secondary metabolites could be of great interest to the scientific community. This study is an attempt to investigate Fijian-based A. planci for their venom and associated actinomycetes antibacterial activity and further identify the type of enzymes present in the crude venom extract. The CoTS venom extract (0.192 g) harbor enzymes such as gelatinase, caesinase, and amylase. An abundant and potent actinomycete strain, represented as FJA1 showed antibacterial activity against Enterococcus faecium with an inhibition zone of 10 mm. Moreover, all pathogenic test microorganisms were resistant against concentrations of 500 µg and 1 mg of A. planci venom extract.
CASE REPORT | doi:10.20944/preprints201911.0379.v2
Subject: Biology, Animal Sciences & Zoology Keywords: animal nocardiosis; Nocardia; veterinary mycology; actinomycetes; Russian Federation; pet; dermatitis; Nocardia asteroides
Online: 3 December 2019 (12:15:22 CET)
Two cases of cutaneous nocardiosis in a cat and in a dog have been described. Diagnosis was made on basis of direct microscopy and cultural mycological analysis. Phenotypic characteristics of two indigenous Nocardia strains are presented. The strain isolated from cat was presumably identified as N. asteroids. There have been no reports of suchlike cases in pets in Russia so far.