Seasonal cambial activity of five tropical tree species in central Thailand

The seasonal cambial activity of five tropical tree species was investigated at Khao Yai National Park. The species studied were Tetrameles nudiflora, Magnolia baillonii, Canarium euphyllum Kur, Toona ciliata, and Spondias axillaris. Cambial activity was quantified by counting layers of undifferentiated cells in the cambium zone from wood anatomical micro sections prepared from wood samples collected in monthly intervals from July 2010 to June 2011. The relationship between cambial activity and climatic factors was investigated by using Pearson’s correlation. The growth dynamics of five studied species differed considerably. The cambium of Tetrameles nudiflora and Magnolia baillonii was most active when rainfall reached its maximum amount in June (mid rainy season), whereas the cambium of Canarium euphyllum, Toona ciliata, and Spondias axillaris was most active in March during the transition from the dry to the wet season.     

Loop residues of the receptor binding domain of Bacillus thuringiensis Cry11Ba toxin are important for mosquitocidal activity

Using a Cry11Ba toxin model, predicted loops in domain II were analyzed for their role in receptor binding and toxicity. Peptides corresponding to loops α8, 1 and 3, but not loop 2, competed with toxin binding to Aedes midgut membranes. Mutagenesis data reveal loops α8, 1 and 3 are involved in toxicity. Loops 1 and 3 are of greater significance in toxicity to Aedes and Culex larvae than to Anopheles. Cry11Ba binds the apical membrane of larval caecae and posterior midgut, and binding can be competed by loop 1 but not by loop 2 peptides. Cry11Ba binds the same regions to which anti-cadherin antibody binds, and this antibody competes with Cry11Ba binding suggesting a possible role of cadherin in toxication.     

Optimization of a two-step biodiesel production process comprised of lipid extraction from blended sewage sludge and subsequent lipid transesterification

As a preliminary research for the development of feasible and economical biodiesel production using blended sewage sludge (BSS), a sustainable and non-edible feedstock, the two-step process comprised of lipid extraction (first step) and subsequent transesterification of the lipid with methanol (second step) was optimized. The total lipid content of the free fatty acid (FFA) containing BSS was determined to be 14.5% using the Blight and Dyer method with ultrasonication pretreatment, where 40.8% of the total lipid content was FFAs. The highest lipid yield of 13.5% (g-lipid/g-dry sludge), corresponding to 92.9% extraction efficiency, was obtained using 20 mL-solvent/g-dry sludge of the total solvent mixture with a 2/1 (v/v) ratio of chloroform and methanol. In the transesterification step, an acidic catalyst (H₂SO₄) exhibited significantly higher performance than an alkaline catalyst (NaOH). Thus, the optimal reaction conditions were 0.2% (g/g-lipid) H₂SO₄, 20 mL-methanol/g-lipid, 70°C and 8 h, respectively. Although the reaction temperature was increased from 50 to 70°C, we could save H₂SO₄, methanol, and a reaction time by 75, 50 and 66.7%, respectively compared with previous optimal conditions suggest by others’ research. Under our optimal conditions, a biodiesel yield of 39.0% (g-biodiesel/g-lipid) and an overall yield (i.e., extraction and transesterification) of 5.3% (g-biodiesel/g-BSS) were achieved, which are substantially higher than those from others’ research.     

Control of ion transport in mouse proximal and distal colon by prolactin.

The lactogenic hormone prolactin (PRL) has been known to affect Ca(2+) and electrolyte transport in the intestinal epithelium. In the present study we analyzed ion transport in mouse proximal and distal colon, and acute changes induced by PRL. In the proximal colon, carbachol activated a Ca(2+) dependent Cl(-) secretion that was sensitive to DIDS and NFA. In the distal colon, both ATP and carbachol activated K(+) secretion. Ca(2+) -activated KCl transport in proximal and distal colon was inhibited by PRL (200 ng/ml), while amiloride sensitive Na(+) absorption and cAMP induced Cl(-) secretion remained unaffected. Luminal large conductance Ca(2+) -activated K(+) (BK) channels were largely responsible for Ca(2+) -activated K(+) secretion in the distal colon, and basolateral BK channels supported Ca(2+) -activated Cl(-) secretion in the proximal colon. Ca(2+) chelating by BAPTA-AM attenuated effects of carbachol and abolished effects of PRL. Both inhibition of PI3 kinase with wortmannin and blockage of MAP kinases with SB 203580 or U 0126, interfered with the acute inhibitory effect of PRL on ion transport, while blocking of Jak/Stat kinases with AG 490 was without effects. PRL attenuated the increase in intracellular Ca(2+) that was caused by stimulation of isolated colonic crypts with carbachol. Thus PRL inhibits Ca(2+) dependent Cl(-) and K(+) secretion by interfering with intracellular Ca(2+) signaling and probably by activating PI3 kinase and MAP kinase pathways.     

Distinct roles for renal particulate and soluble guanylyl cyclases in preserving renal function in experimental acute heart failure

Worsening renal function in the setting of human acute heart failure (AHF) predicts poor outcomes, such as rehospitalization and increased mortality. Understanding potential renoprotective mechanisms is warranted. The guanylate cyclase (GC) enzymes and their second messenger cGMP are the target of two important circulating neurohumoral systems with renoprotective properties. Specifically, natriuretic peptides (NP) released from the heart with AHF target particulate GC in the kidney, while the nitric oxide (NO) system is an activator of renal soluble GC. We hypothesized that both systems are essential to preserve renal excretory and hemodynamic function in AHF but with distinct roles. We investigated these roles in three groups of anesthetized dogs (6 each) with AHF induced by rapid ventricular pacing. After a baseline AHF clearance, each group received intrarenal vehicle (control), N(G)-monomethyl-l-arginine (l-NMMA), a competitive NO inhibitor (50 microg.kg(-1).min(-1)) or a specific NP receptor antagonist, HS-142-1 (0.5 mg/kg). We observed that intrarenal l-NMMA decreased renal blood flow (RBF) without significant decreases in glomerular filtration rate (GFR), urinary sodium excretion (UNaV), or urinary cGMP. In contrast, HS-142-1 resulted in a decrease in UNaV and cGMP excretion together with a reduction in GFR and an increase in distal fractional tubular sodium reabsorption. We conclude that in AHF, the NP system plays a role in maintaining sodium excretion and GFR, while the function of NO is in the maintenance of RBF. These studies have both physiological and therapeutic implications warranting further research into cardiorenal interactions in this syndrome of AHF.     

Targeted functional investigations guided by integrative proteome network analysis revealed significant perturbations of renal tubular cell functions induced by high glucose

Recently, several studies employed various proteomic approaches to define diabetes‐induced changes in renal proteins. However, functional significance of those datasets in diabetic nephropathy remained unclear. We thus performed integrative proteome network analysis of such datasets followed by various targeted functional studies in distal renal tubular cells treated with high glucose (HG) (25 mM) compared to normal glucose (NG) (5.5 mM) and NG + mannitol (M) (5.5 + 19.5 mM). The data showed that at 96 h when cell proliferation/death, tight junction protein and β‐/F‐actin expression and organization, and transepithelial resistance remained unchanged, only HG caused increased levels of HSP90, HSP70, and HSP60, and increased accumulation of intracellular protein aggregates. In addition, HG also induced overproduction of intracellular ROS, decreased catalase level, increased level of oxidatively modified proteins, increased intracellular ATP level, and defective transepithelial Ca²⁺ transport. However, both HG and M increased the levels of ubiquitinated proteins. Taken together, this study demonstrated significant perturbations of distal renal tubular cells induced by HG based on targeted functional studies guided by integrative proteome network analysis. These data may, at least in part, lead to better understanding of the pathogenic mechanisms of diabetic nephropathy.     

Genetic Diversity of the Giant Tiger Shrimp (Penaeus monodon) in Thailand Revealed by PCR-SSCP of Polymorphic EST-Derived Markers

A total of 90 ESTs from normal and 157 from subtractive ovarian cDNA libraries of the giant tiger shrimp (Penaeus monodon) were sequenced. SSCP analysis of disulfide isomerase (DSl), zinc finger protein (ZFP), PMO920, and PMT1700 was carried out for population genetic studies of P. monodon in Thai waters. The number of codominant alleles per locus for overall samples was 6 for PMO920, 5 for PMT1700, and 12 for ZFP, and there were 19 dominant alleles for DSI. The observed heterozygosity of each geographic sample was 0.3043–0.5128 for PMO920, 0.3462–0.4643 for PMT1700, and 0.5000–0.8108 for ZFP. Linkage disequilibrium analysis indicated that genotypes of these loci segregate randomly (P > 0.05). Low genetic distance was found between pairs of geographic samples (0.0077–0.0178). The neighbor-joining tree constructed from the average genetic distance of overall loci allocated the Andaman samples (Satun, Trang, and Phangnga) into one cluster, and Chumphon and Trat into other clusters. Geographic differentiation between Satun-Trat and Satun-Phangnga was found only at the ZFP locus (P < 0.05), suggesting low degrees of genetic subdivision of Thai P. monodon.