6 research outputs found
Vittatispora, a New Melanosporaceous Genus From Indian Soil
Vittatispora coorgii gen. sp. nov., isolated from soil in India, is described and illustrated. The fungus has morphological characteristics of the genera Melanospora, Sphaerodes and Syspastospora. The most striking feature is the presence of a thick hyaline ridge along the vertical axis of the lemonshaped ascospores wall. Perithecia also have a long neck composed of adhering hyphae, similar to that of Syspatospora. Phylogenetic studies on the 28S rDNA indicate it is closely related to Melanospora and Sphaerodes and belongs in the Ceratostomataceae. The new genus is based on the distinctive morphology and phylogenetic analyses. The fungus grew in culture only conjointly with a sterile fungus which a BLAST analysis suggested was close to Tetracladium marchalianum
Enhancement in production of recombinant two-chain Insulin Glargine by over-expression of Kex2 protease in Pichia pastoris
Glargine is an analog of Insulin currently being
produced by recombinant DNA technology using two
different hosts namely Escherichia coli and Pichia
pastoris. Production from E. coli involves the steps of
extraction of inclusion bodies by cell lysis, refolding,
proteolytic cleavage and purification. In P. pastoris, a
single-chain precursor with appropriate disulfide bonding
is secreted to the medium. Downstream processing currently
involves use of trypsin which converts the precursor
into two-chain final product. The use of trypsin in the
process generates additional impurities due to presence of
Lys and Arg residues in the Glargine molecule. In this
study, we describe an alternate approach involving overexpression
of endogenous Kex2 proprotein convertase,
taking advantage of dibasic amino acid sequence (ArgArg)
at the end of B-chain of Glargine. KEX2 gene overexpression
in Pichia was accomplished by using promoters
of varying strengths to ensure production of greater
levels of fully functional two-chain Glargine product,
confirmed by HPLC and mass analysis. In conclusion,
this new production process involving Kex2 protease
over-expression improves the downstream process efficiency,
reduces the levels of impurities generated and
decreases the use of raw material
Mannose-binding Lectin-deficient Mice Are Susceptible to Infection with Staphylococcus aureus
Gram-positive organisms like Staphylococcus aureus are a major cause of morbidity and mortality worldwide. Humoral response molecules together with phagocytes play a role in host responses to S. aureus. The mannose-binding lectin (MBL, also known as mannose-binding protein) is an oligomeric serum molecule that recognizes carbohydrates decorating a broad range of infectious agents including S. aureus. Circumstantial evidence in vitro and in vivo suggests that MBL plays a key role in first line host defense. We tested this contention directly in vivo by generating mice that were devoid of all MBL activity. We found that 100% of MBL-null mice died 48 h after exposure to an intravenous inoculation of S. aureus compared with 45% mortality in wild-type mice. Furthermore, we demonstrated that neutrophils and MBL are required to limit intraperitoneal infection with S. aureus. Our study provides direct evidence that MBL plays a key role in restricting the complications associated with S. aureus infection in mice and raises the idea that the MBL gene may act as a disease susceptibility gene against staphylococci infections in humans