A total of 94 actinomycete strains were isolated from the marine sediments of a shrimp farm, 87.2% belonged to the genus Streptomyces, others were Micromonospora spp. Fifty-one percent of the actinomycete strains showed activity against the pathogenic Vibrio spp. strains. Thirty-eight percent of marine Streptomyces strains produced siderophores on chrome azurol S (CAS) agar plates. Seven strains of Streptomyces were found to produce siderophores and to inhibit the growth of Vibrio spp. in vitro. Two of them belonged to the Cinerogriseus group, the most frequently isolated group of Streptomyces. The results showed that streptomycetes could be a promising source for biocontrol agents in aquaculture.
Lactoferrin is a multifunctional, iron-binding glycoprotein found in physiological fluids of mammals. Many functions of lactoferrin are thought to be involved in the N-lobe. In the present study, a gene encoding the N-lobe of porcine lactoferrin was cloned and expressed in Pichia methanolica. The gene contains 1038 bp, an "AGG" codon between 1039-1041bp in the PLF gene was replaced with a "TAA" stop codon through primer design and PCR. The sequencing results were aligned with the sequence (Genbank, L77887), indicating that the homology between these two sequences was 99%. The porcine lactoferrin N-lobe (PLfN) was expressed successfully in Pichia methanolica, and was secreted into the culture medium. The protein translated from the new ORF contained 346 amino acid residues, including a 17-amino acid signal peptide, its MW was approximately 42 kD, and it possessed antibacterial activity toward Escherichia coli ATCC25922. The method established in our study will pave the way for efficient industrial production of recombinant PLfN on a large scale for future utilization of this protein as a feed additive.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.