Improvement in Production and Quality of Gellan Gum by Sphingomonas paucimobilis Under High Dissolved Oxygen Tension Levels

The effect of agitation rate and dissolved oxygen tension (DOT) on growth and gellan production by Sphingomonas paucimobilis was studied. Higher cell growth of 5.4 g l⁻¹ was␣obtained at 700 rpm but maximum gellan (15 g l⁻¹) was produced at 500 rpm. DOT levels above 20% had no effect on cell growth but gellan yield was increased to 23 g l⁻¹ with increase in DOT level to 100%. Higher DOT levels improved the viscosity and molecular weight of the polymer with change in acetate and glycerate content of the polymer.     

Technological aspects of extractive fermentation using aqueous two-phase systems

World Journal of Microbiology and Biotechnology -     

The identity of a myelin-like fraction isolated from developing brain

1. A myelin-like membrane fraction was isolated from developing rat brain by a new method. 2. The chemical composition and morphology of the fraction are described. 3. The myelin-like fraction is similar to myelin in characteristic enzyme activity but differs in the absence of basic protein and cerebrosides. No similarity to other subcellular fractions was observed. 4. It is suggested that the myelin-like fraction is a stage in the formation of compact myelin from glial plasma membrane. 5. ;Early' myelin consists of the myelin-like and compact myelin fractions from developing brain.     

Endoplasmic reticulum stress,autophagic and apoptotic cell death,and immune activation by a natural triterpenoid in human prostate cancer cells

Though the current therapies are effective at clearing an early stage prostate cancer, they often fail to treat late-stage metastatic disease. We aimed to investigate the molecular mechanisms underlying the anticancer effects of a natural triterpenoid, ganoderic acid DM (GA-DM), on two human prostate cancer cell lines: the androgen-independent prostate carcinoma (PC-3), and androgen-sensitive prostate adenocarcinoma (LNCaP). Cell viability assay showed that GA-DM was relatively more toxic to LNCaP cells than to PC-3 cells (IC₅₀s ranged 45-55 µM for PC-3, and 20-25 µM for LNCaP), which may have occurred due to differential expression of p53. Hoechst DNA staining confirmed detectable nuclear fragmentation in both cell lines irrespective of the p53 status. GA-DM treatment decreased Bcl-2 proteins while it upregulated apoptotic Bax and autophagic Beclin-1, Atg5, and LC-3 molecules, and caused an induction of both early and late events of apoptotic cell death. Biochemical analyses of GA-DM-treated prostate cancer cells demonstrated that caspase-3 cleavage was notable in GA-DM-treated PC-3 cells. Interestingly, GA-DM treatment altered cell cycle progression in the S phase with a significant growth arrest in the G2 checkpoint and enhanced CD4 ⁺ T cell recognition of prostate tumor cells. Mechanistic study of GA-DM-treated prostate cancer cells further demonstrated that calpain activation and endoplasmic reticulum stress contributed to cell death. These findings suggest that GA-DM is a candidate for future drug design for prostate cancer as it activates multiple pathways of cell death and immune recognition.     

Molecular evolution of mammalian lactate dehydrogenase-A genes and pseudogenes: association of a mouse processed pseudogene with a B1 repetitive sequence

A mouse genomic clone containing a lactate dehydrogenase-A (LDH-A) processed pseudogene and a B1 repetitive element was isolated, and a nucleotide sequence of approximately 3 kb was determined. The pseudogene and B1 element are flanked by perfect 13-bp repeats, and the B1 sequence starts at 14 nucleotides 3' to the presumptive polyadenylation signal of the pseudogene. The nucleotide sequences of the LDH-A genes and processed pseudogenes from mouse, rat, and human were compared, and a phylogenetic tree was constructed. The rate and pattern of nucleotide substitutions in the LDH-A pseudogenes are similar to previously reported results (Li et al. 1984). The average rate of nucleotide substitutions in the LDH-A pseudogenes is 4.3 X 10(- 9)/site/year. The substitutions of C----T and G----A are most frequent, and A----G substitutions are relatively high. The rate of synonymous substitutions in the LDH-A genes is 5.3 X 10(-9), which is not significantly higher than the average rate of 4.7 X 10(-9) for 35 mammalian genes. The rate of nonsynonymous substitutions in the LDH-A genes is 0.20 X 10(-9), which is considerably lower than the average rate of 0.88 X 10(-9) for 35 mammalian genes. Thus, the mammalian LDH-A gene appears to be highly conserved in evolution.      

Studies on the efficacy of a phytohormone producing phosphate solubilizingBacillus firmus in augmenting paddy yield in acid soils of Nagaland

Summary A super strain ofBacillus firmus (NCIM-2636) producing a phytohormone, indole-3-acetic acid, in addition to its high ability to solubilize insoluble inorganic phosphates were applied in acid soils of Nagaland, India. Rice (Oryza sativa L.) variety Jaya and IR-8 were grown in kharif season in two successive years 1980 and 1981. After proper manuring the soils received single super phosphate (S.S.P.) and Mussoorie Rock phosphate (R.P.) separately at different doses. Yield of crop in both the years increased significantly due to bacterial inoculation. Maximum grain yield was recorded in Jaya variety under S.S.P. and R.P. when treatments were at the dose of 43.75 and 17.5 kg P ha⁻¹ respectively while the same in IR-8 variety under S.S.P. and R.P. treatments were at the dose of 35 and 17.5 kg P ha⁻¹ respectively. Maximum straw yield was produced by Jaya variety when 35 and 43.75 kg P ha⁻¹ in the form of S.S.P. and R.P. respectively were applied. Highest straw yield of IR-8 variety was obtained after the application of 17.5 kg P ha⁻¹ (S.S.P. and R.P.) in combination with phosphate solubilizing bacteria. Bacterial inoculation decreased the phosphorus availability in 1 st year but increased the same in 2nd year. Phosphorus content in grains was significantly enhanced in both the trials. Maximum uptake of phosphorus by grains was noted in Jaya variety at the dose of 47.5 kg P ha⁻¹ and in IR-8 variety at the dose of 52.5 kg P ha⁻¹ under S.S.P. treatment, while 8.75 and 35 kg P ha⁻¹ in the form of R.P. yielded similar results in Jaya and IR-8 varieties respectively. Phosphorus at the dose of 35 kg ha⁻¹ was found to cause more P-uptake by straw in both S.S.P. and R.P. treatments. The various data from the experiment conclusively proved that the bacterium in combination with R.P. produced the desired effect more prominently than when bacterium applied in combination with S.S.P.