Factors affecting lipase production in Syncephalastrum racemosum

Syncephalastrum racemosum grown as a static culture showed maximum lipase production at 30°C in 2d at pH 8.0. When the medium was supplemented with fructose, maximum production of lipase per unit of growth was achieved, followed by raffinose, sucrose, ribose, galactose, maltose, lactose, mannitol and glucose. Amongst the nitrogen sources tested, corn steep liquor at 8% (v/v) produced maximum enzyme; there was evidence of catabolite repression by glucose when groundnut protein, soybean meal, milk casein or wheat bran were the sources of nitrogen. Calcium, potassium and sodium citrates, each at 0.1% (w/v), increased the yield of lipase.     

Deep vein thrombosis: Current status and nanotechnology advances

Deep vein thrombosis (DVT) affects up to 2 million people in the United States, and worldwide incidence is 70 to 113 cases per 100,000 per year. Mortality from DVT is often due to subsequent pulmonary embolism (PE). Precise diagnosis and treatment is thereby essential for the management of DVT. DVT is diagnosed by a thorough history and physical examination followed by laboratory and diagnostic tests. The choice of laboratory and diagnostic test is dependent on clinical pretest probability. Available laboratory and diagnostic techniques mainly involve D-dimer test, ultrasound, venography, and magnetic resonance imaging. The latter two diagnostic tools require high doses of contrast agents including either radioactive or toxic materials. The available treatment options include lifestyle modifications, mechanical compression, anticoagulant therapy, inferior vena cava filter, and thrombolysis/thrombolectomy. All of these medical and surgical treatments have serious side effects including improper clot clearance and increased risk of hemorrhage occurrence. Therefore, research in this field has recently focused on the development of non-invasive and accurate diagnostics, such as ultrasound enhanced techniques and molecular imaging methods, to assess thrombus location and its treatment course. The frontier of nanomedicine also shows high prospects in tackling DVT with efficient targeted drug delivery. This review describes the pathology of DVT along with successive medical problems such as PE and features a detailed listing of various diagnostic and therapeutic modalities that have been in use and are under development.     

The light of the firefly under the influence of ethyl acetate

When a firefly is made to inhale ethyl acetate vapour, a constant glow appears after a few minutes from its abdominal lantern. This control experiment has been performed by a few workers to record the emission spectrum of the firefly. However, a time-resolved experiment performed by us on this continuous light emitted by the species Luciola praeusta Kiesenwetter 1874 (Coleoptera: Lampyridae: Luciolinae) reveals that it is composed of a continuous train of tiny pulses! The nature of the pulses suggests that an oscillatory chemical reaction continues in the microsecond time scale in the lantern of the anaesthetized firefly.     

Comparison of the rates of enzymatic hydrolysis of pretreated rice straw and bagasse with celluloses

The rates of enzymatic hydrolysis of pretreated rice straw and bagasse have been studied and compared with the hydrolysis rates of microcrystalline cellulose powder (MCCP) and Solka Floc. The effects of particle size reduction and enzyme loading on the rates of hydrolysis of rice straw and bagasse were also studied. It was found that the rates of hydrolysis of pretreated rice straw and bagasse are much higher than that of MCCP and Solka Floc. For both rice straw and bagasse, particle size reduction had very little effect in enhancing the rate of hydrolysis. Lignin present at <10% did not seem to hinder the accessibility of the enzyme to the cellulose surface. An enzyme loading > 40 Ug^?1 had no effect on the hydrolysis rate of rice straw or bagasse.     

Bridging the membrane lipid divide: bacteria of the FCB group superphylum have the potential to synthesize archaeal ether lipids

Archaea synthesize membranes of isoprenoid lipids that are ether-linked to glycerol-1-phosphate (G1P), while Bacteria/Eukarya produce membranes consisting of fatty acids ester-bound to glycerol-3-phosphate (G3P). This dichotomy in membrane lipid composition (i.e., the ‘lipid divide’) is believed to have arisen after the Last Universal Common Ancestor (LUCA). A leading hypothesis is that LUCA possessed a heterochiral ‘mixed archaeal/bacterial membrane’. However, no natural microbial representatives supporting this scenario have been shown to exist today. Here, we demonstrate that bacteria of the Fibrobacteres–Chlorobi–Bacteroidetes (FCB) group superphylum encode a putative archaeal pathway for ether-bound isoprenoid membrane lipids in addition to the bacterial fatty acid membrane pathway. Key genes were expressed in the environment and their recombinant expression in Escherichia coli resulted in the formation of a ‘mixed archaeal/bacterial membrane’. Genomic evidence and biochemical assays suggest that the archaeal-like lipids of members of the FCB group could possess either a G1P or G3P stereochemistry. Our results support the existence of ‘mixed membranes’ in natural environments and their stability over a long period in evolutionary history, thereby bridging a once-thought fundamental divide in biology.Subject terms: Water microbiology, Cellular microbiology, Molecular evolution, Metagenomics     

Structural studies on a 2,3-diphosphoglycerate independent phosphoglycerate mutase from Bacillus stearothermophilus.

Phosphoglycerate mutase (PGM), an important enzyme in the glycolytic pathway, catalyzes the transfer of a phosphate group between the 2 and the 3 positions of glyceric acid. The gene coding for the 2, 3-diphosphoglycerate independent monomeric PGM from Bacillus stearothermophilus (57 kDa), whose activity is extremely pH sensitive and has an absolute and specific requirement for Mn2+, has been cloned and the enzyme overexpressed and purified to homogeneity. Circular dichroism studies showed at most only small secondary structure changes in the enzyme upon binding to Mn2+ or its 3-phosphoglycerate substrate, but thermal unfolding analyses revealed that Mn2+ but not 3-phosphoglycerate caused a large increase in the enzyme's stability. Diffraction-quality crystals of the enzyme were obtained at neutral pH in the presence of 3-phosphoglyceric acid with ammonium sulfate as the precipitating agent; these crystals diffract X rays to beyond 2.5-A resolution and belong to the orthorhombic space group C2221 with unit cell dimensions, a = 58.42, b = 206.08, c = 124.87 A, and alpha = beta = gamma = 90.0 degrees. The selenomethionyl version of the B. stearothermophilus protein has also been overexpressed, purified, and crystallized. Employing these crystals, the determination of the three-dimensional structure of this PGM by the multiwavelength anomalous dispersion method is in progress.     

Choline-phosphate cytidyltransferase activity and phosphatidylcholine synthesis in rat granular pneumocytes are increased with exogenous fatty acids

We investigated the effect of exogenous fatty acids on phosphatidylcholine (PC) and disaturated phosphatidylcholine (DSPC) synthesis by rat granular pneumocytes in primary culture. Synthesis of PC and DSPC from [3H-methyl]choline, as evaluated by increasing specific activity (pmol choline incorporated/microgram phosphorus), was linear for 3 h. Exogenous palmitic, oleic, linoleic, or linolenic acid (100 microM each) increased the synthesis of PC by approx. 50% during incubation for 3 h. In contrast, synthesis of DSPC was increased only by palmitic acid. The increase in DSPC synthesis was approx. 150% after 3 h. Conversion of choline phosphate to PC was increased in the presence of palmitic or oleic acid as indicated by pulse-chase studies with [3H-methyl]choline in the intact cells. Cells incubated for 3 h with either oleic or palmitic acid showed increased choline-phosphate cytidyltransferase activity in the cells and the microsomal fraction. In addition, oleic acid increased the activity of this enzyme in the cytosolic fraction. The distribution of this enzyme in cytosolic and microsomal fraction was 24 and 76% in the cells incubated with palmitic acid and 32 and 68% in control cells. These results suggest that exogenous fatty acids stimulate the de novo pathway of PC synthesis in granular pneumocytes by increasing the microsomal choline-phosphate cytidyltransferase activity.     

Dietary restriction and aging, 2009

Dietary restriction (DR) is a robust nongenetic, nonpharmacological intervention that is known to increase active and healthy lifespan in a variety of species. Despite a variety of differences in the protocols and the way DR is carried out in different species, conserved relationships are emerging among multiple species. 2009 saw the field of DR mature with important mechanistic insights from multiple species. A report of lifespan extension in rapamycin‐treated mice suggested that the TOR pathway, a conserved mediator of DR in invertebrates, may also be critical to DR effects in mammals. 2009 also saw exciting discoveries related to DR in various organisms including yeast, worms, flies, mice, monkeys and humans. These studies complement each other and together aim to deliver the promise of postponing aging and age‐related diseases by revealing the underlying mechanisms of the protective effects of DR. Here, we summarize a few of the reports published in 2009 that we believe provide novel directions and an improved understanding of dietary restriction.