Vaccination with purified capsular polysaccharide Vi Ag from Salmonella typhi can protect against typhoid fever, although the mechanism for its efficacy is not clearly established. In this study, we have characterized the B cell response to this vaccine in wild-type and T cell-deficient mice. We show that immunization with typhoid Vi polysaccharide vaccine rapidly induces proliferation in B1b p...

Pathogenesis of infectious disease is not only determined by the virulence of the microbe but also by the immune status of the host. Vaccination is the most effective means to control infectious diseases. A hallmark of the adaptive immune system is the generation of B cell memory, which provides a long-lasting protective antibody response that is central to the concept of vaccination. Recent st...

4''-Oxo-avermectin is a key intermediate in the manufacture of the insecticide emamectin benzoate from the natural product avermectin. Seventeen Streptomyces strains with the ability to oxidize avermectin to 4''-oxo-avermectin in a regioselective manner have been discovered, and the enzymes responsible for this reaction were found to be CYPs (cytochrome P450 mono-oxygenases). The genes for thes...

Avermectins are useful anthelmintic antibiotics produced by Streptomyces avermitilis. We demonstrated that a novel AraC-family transcriptional regulator in this species, SAV742, is a global regulator that negatively controls avermectin biosynthesis and cell growth, but positively controls morphological differentiation. Deletion of its gene, sav_742, increased avermectin production and dry cell ...

The 2015 Nobel Prize in Physiology or Medicine has been awarded to avermectins and artemisinin, respectively. Avermectins produced by Streptomyces avermitilis are excellent anthelmintic and potential antibiotic agents. Because wild-type strains only produce low levels of avermectins, much research effort has focused on improvements in avermectin production to meet the ever increasing demand for...

Avermectins, a group of anthelmintic and insecticidal agents produced from Streptomyces avermitilis, are widely used in agricultural, veterinary, and medical fields. This study presents the first report on the potential of using nanosecond pulsed electric fields (nsPEFs) to improve avermectin production in S. avermitilis. The results of colony forming units showed that 20 pulses of nsPEFs at 10...

The model organism Streptomyces coelicolor A3(2) harbors a 356-kb linear plasmid, SCP1. We report here development of a recombinational cloning method for deleting large segment from one telomere of SCP1 followed by replacing with the telomere of pSLA2 and sequentially inserting with the overlapping cosmids in vivo. The procedure depends on homologous recombination coupled with cleavage at telo...

Avermectins are a group of macrocyclic lactones that commonly used as pesticides to treat pests and parasitic worms. Some members the avermectin family, such ivermectin, have been found exhibit anti-proliferative activity toward cancer cells. This study aimed investigate potential anti-cancer activities B1a using HCT-116 colon cell line. The MTT assay was calculate IC50 by incubating cells with...

To understand the efficacy of emamectin benzoate, avermectin, milbemectin, and thiacloprid on the reproduction and development of Bursaphelenchus xylophilus, seven parameters, namely population growth, fecundity, egg hatchability, larval lethality, percent larval development, body size, and sexual ratio, were investigated using sublethal (LC20) doses of these compounds in the laboratory. Emamec...