Fermentation of enzymatically saccharified sunflower stalks for ethanol production and its scale up

Pretreated sunflower stalks saccharified with a Trichoderma reesei Rut-C 30 cellulase showed 57.8% saccharification. Enzyme hydrolysate concentrated to 40 g/l reducing sugars was fermented under optimum conditions of fermentation time (24 h), pH (5.0), temperature (30 degrees C) and inoculum size (3% v/v) and, showed a maximum ethanol yield of 0.444 g/g ethanol. Ethanol production scaled up in a 1 l and a 15 l fermenter under optimum conditions revealed maximum ethanol yields of 0.439 and 0.437 g/g respectively.     

Central LIF gene therapy suppresses food intake,body weight,serum leptin and insulin for extended periods

Leukemia inhibitory factor (LIF) overexpression, induced by the intracerebroventricular (i.c.v.) injection of an recombinant adeno-associated viral vector encoding LIF (rAAV-LIF), resulted in a dose-dependent reduction in body weight (BW) gain, food intake (FI) and adiposity, evidenced by suppression of serum leptin and free fatty acids for an extended period in outbred adult female rats. A dose-dependent reduction in serum insulin levels and unchanged serum glucose, energy expenditure through thermogenesis as indicated by uncoupling protein-1 (UCP-1) mRNA expression in brown adipose tissue (BAT), and metabolism as indicated by serum T3 and T4, accompanied the blockade of weight gain. Thus, central rAAV-LIF therapy is a viable strategy to voluntarily reduce appetite and circumvent leptin resistance, a primary factor underlying age-dependent weight gain and obesity in rodents and humans.     

A selective sweep driven by pyrimethamine treatment in southeast asian malaria parasites

Malaria parasites (Plasmodium falciparum) provide an excellent system in which to study the genomic effects of strong selection in a recombining eukaryote because the rapid spread of resistance to multiple drugs during the last the past 50 years has been well documented, the full genome sequence and a microsatellite map are now available, and haplotype data can be easily generated. We examined microsatellite variation around the dihydrofolate reductase (dhfr) gene on chromosome 4 of P. falciparum. Point mutations in dhfr are known to be responsible for resistance to the antimalarial drug pyrimethamine, and resistance to this drug has spread rapidly in Southeast (SE) Asia after its introduction in 1970s. We genotyped 33 microsatellite markers distributed across chromosome 4 in 61 parasites from a location on the Thailand/Myanmar border. We observed minimal microsatellite length variation in a 12-kb (0.7-cM) region flanking the dhfr gene and diminished variation for approximately 100 kb (6 cM), indicative of a single origin of resistant alleles. Furthermore, we found the same or similar microsatellite haplotypes flanked resistant dhfr alleles sampled from 11 parasite populations in five SE Asian countries indicating recent invasion of a single lineage of resistant dhfr alleles in locations 2000 km apart. Three features of these data are of especially interest. (1). Pyrimethamine resistance is generally assumed to have evolved multiple times because the genetic basis is simple and resistance can be selected easily in the laboratory. Yet our data clearly indicate a single origin of resistant dhfr alleles sampled over a large region of SE Asia. (2). The wide valley ( approximately 6 cM) of reduced variation around dhfr provides "proof-of-principle" that genome-wide association may be an effective way to locate genes under strong recent selection. (3). The width of the selective valley is consistent with predictions based on independent measures of recombination, mutation, and selection intensity, suggesting that we have reasonable estimates of these parameters. We conclude that scanning the malaria parasite genome for evidence of recent selection may prove an extremely effective way to locate genes underlying recently evolved traits such as drug resistance, as well as providing an opportunity to study the dynamics of selective events that have occurred recently or are currently in progress.     

Inhibition of caspase-9 through phosphorylation at Thr 125 by ERK MAPK

Many pro-apoptotic signals activate caspase-9, an initiator protease that activates caspase-3 and downstream caspases to initiate cellular destruction. However, survival signals can impinge on this pathway and suppress apoptosis. Activation of the Ras-Raf-MEK-ERK mitogen-activated protein kinase (MAPK) pathway is associated with protection of cells from apoptosis and inhibition of caspase-3 activation, although the targets are unknown. Here, we show that the ERK MAPK pathway inhibits caspase-9 activity by direct phosphorylation. In mammalian cell extracts, cytochrome c-induced activation of caspases-9 and -3 requires okadaic-acid-sensitive protein phosphatase activity. The opposing protein kinase activity is overcome by treatment with the broad-specificity kinase inhibitor staurosporine or with inhibitors of MEK1/2. Caspase-9 is phosphorylated at Thr 125, a conserved MAPK consensus site targeted by ERK2 in vitro, in a MEK-dependent manner in cells stimulated with epidermal growth factor (EGF) or 12-O-tetradecanoylphorbol-13-acetate (TPA). Phosphorylation at Thr 125 is sufficient to block caspase-9 processing and subsequent caspase-3 activation. We suggest that phosphorylation and inhibition of caspase-9 by ERK promotes cell survival during development and tissue homeostasis. This mechanism may also contribute to tumorigenesis when the ERK MAPK pathway is constitutively activated.     

Polyester and polycarbonate synthesis by in vitro enzyme catalysis

Enzyme technology has significantly expanded in scope and impact over the past 10 years to include organic transformations in non-traditional environments. This is in part due to an increased understanding and capability of using enzyme catalysis in a wide variety of organic solvents, at interfaces, and at high temperatures and pressures. This review focuses on a relatively new but rapidly expanding research activity where in vitro enzyme catalysis is used for the synthesis of non-natural polyesters and polycarbonates. The inclination to use of enzymes for polymer synthesis has been fueled by a desire to carry out these reactions in the absence of heavy metals, at lower temperatures, and with increased selectivity. Aspects of this work that include enzyme-catalyzed step-growth condensation reactions, chain-growth ring-opening polymerizations, and corresponding transesterification of macromolecular substrates are discussed.     

A GABA-neuropeptide Y (NPY) interplay in LH release

Neuropeptide Y (NPY) stimulates and gamma-amino butyric acid (GABA) inhibits LH release in the rat. Since a sub-population of NPY-producing neurons in the arcuate nucleus (ARC) of the hypothalamus co-express GABA, the possibility of an interplay between NPY and GABA in the release of LH was investigated in two ways. First by employing light and electron microscopic double staining for NPY and GABA, using pre and post-immunolabeling on rat brain sections, we detected GABA in NPY immunoreactive axon terminals in the MPOA, one of the primary sites of action of these neurotransmitters/neuromodulators in the regulation of LH release. These morphological findings raised the possibility that inhibitory GABA co-released with NPY may act to restrain the excitatory effects of NPY on LH release. Muscimol (MUS, 0.44 or 1.76 nmol/rat), a GABA(A) receptor agonist, administered intracerebroventricularly (icv), alone failed to affect LH release, but NPY (0.47 nmol/rat icv) alone stimulated LH release in ovarian steroid-primed ovariectomized rats. On the other hand, administration of MUS blocked the NPY-induced stimulation of LH release in a dose-dependent manner. Similarly, administration of MUS abolished the excitatory effects on LH release of 1229U91, a selective NPY Y4 receptor agonist. These results support the possibility that in the event of co-release of these neurotransmitters/neuromodulators, GABA may act to restrain stimulation of LH release by NPY during the basal episodic and cyclic release of LH in vivo.     

beta-amyloid-induced migration of monocytes across human brain endothelial cells involves RAGE and PECAM-1

In patients withamyloid -related cerebrovascular disorders, e.g., Alzheimer'sdisease, one finds increased deposition of amyloid peptide (A) andincreased presence of monocyte/microglia cells in the brain. However,relatively little is known of the role of A in the trafficking ofmonocytes across the blood-brain barrier (BBB). Our studies show thatinteraction of A_1-40 with monolayer of human brainendothelial cells results in augmented adhesion and transendothelialmigration of monocytic cells (THP-1 and HL-60) and peripheral bloodmonocytes. The A-mediated migration of monocytes was inhibited byantibody to A receptor (RAGE) and platelet endothelial cell adhesionmolecule (PECAM-1). Additionally, A-induced transendothelialmigration of monocytes were inhibited by protein kinase C inhibitor andaugmented by phosphatase inhibitor. We conclude that interaction ofA with RAGE expressed on brain endothelial cells initiates cellularsignaling leading to the transendothelial migration of monocytes. Wesuggest that increased diapedesis of monocytes across the BBB inresponse to A present either in the peripheral circulation or in thebrain parenchyma may play a role in the pathophysiology of A-relatedvascular disorder.

     

Auxin — Calcium Interaction in Adventitious Root Formation in the Hypocotyl Explants of Sunflower (Helianthus annuus L.)

Auxin-calcium interaction has been studied to understand their involvement in adventitious root initiation from the hypocotyl explants of sunflower (Helianthus annuus L.). When hypocotyl explants were cultured on MS medium (containing calcium), 1 mg l^-1 IAA was found to be optimal for root induction. However, the hypocotyl explants washed in EGTA (10_-5M) solution for the removal of extracellular calcium, when cultured on medium containing IAA and calcium, exhibited enhanced rooting response. When EGTA-washed explants were cultured on the medium supplemented with lanthanum chloride (10^-6 and 10^-5M), it resulted in the inhibition of the rooting response and this inhibitory effect could be alleviated by the simultaneous addition of IAA. Similar observations have been made by using calcium channel blockers, verapamil and TMB-8, and also a calmodulin inhibitor, trifluoperazine. A net influx of extracellular calcium in the differentiating cells is thus presumed to accompany the auxin-induced response. These results have been discussed in light of initial lack of polarity in the decapitated hypocotyl segments subjected to auxin treatment.     

Validation of computational fluid dynamics methodology used for human upper airway flow simulations

An anatomically accurate human upper airway model was constructed from multiple magnetic resonance imaging axial scans. This model was used to conduct detailed Computational Fluid Dynamics (CFD) simulations during expiration, to investigate the fluid flow in the airway regions where obstruction could occur. An identical physical model of the same airway was built using stereo lithography. Pressure and velocity measurements were conducted in the physical model. Both simulations and experiments were performed at a peak expiratory flow rate of 200 L/min. Several different numerical approaches within the FLUENT commercial software framework were used in the simulations; unsteady Large Eddy Simulation (LES), steady Reynolds-Averaged Navier-Stokes (RANS) with two-equation turbulence models (i.e. k?ε, standard k?ω, and k?ω Shear Stress Transport (SST)) and with one-equation Spalart–Allmaras model. The CFD predictions of the average wall static pressures at different locations along the airway wall were favorably compared with the experimental data. Among all the approaches, standard k?ω turbulence model resulted in the best agreement with the static pressure measurements, with an average error of ～20% over all ports. The highest positive pressures were observed in the retroglossal regions below the epiglottis, while the lowest negative pressures were recorded in the retropalatal region. The latter is a result of the airflow acceleration in the narrow retropalatal region. The largest pressure drop was observed at the tip of the soft palate. This location has the smallest cross section of the airway. The good agreement between the computations and the experimental results suggest that CFD simulations can be used to accurately compute aerodynamic flow characteristics of the upper airway.