Fatty acid efficiency profile in uncoupling of <Emphasis Type="Italic">Acanthamoeba castellanii</Emphasis> mitochondria

A profile of free fatty acid (FFA) specificity in Acanthamoeba castellanii mitochondrial uncoupling is described. The FFA uncoupling specificity was observed as different abilities to stimulate resting respiration, to decrease resting membrane potential, and to decrease oxidative phosphorylation efficiency. Tested unsaturated FFA (C18–20) were more effective as uncouplers and protonophores when compared to tested saturated FFA (C8–18), with palmitic acid (C16:0) as the most active. As FFA efficiency in mitochondrial uncoupling is related to physiological changes of fatty acid composition (and thereby FFA availability) during growth of amoeba cells, it could be a way to regulate the activity of an uncoupling protein and thereby the efficiency of oxidative phosphorylation during a cell life of this unicellular organism. Aleksandra Swida and Małgorzata Czarna contributed equally to this work.     

Downregulation of both gene expression and activity of Hsp27 improved maturation of mouse oocyte in vitro

Background  

Heat shock protein 27 (Hsp27), a member of the small heat shock protein family, is an apoptosis regulator. Our previous proteomic study showed that Hsp27 mainly expressed in human oocyte, and that Hsp27 expression was downregulated in the ovaries derived from women with the polycystic ovary syndrome (PCOS), a well known endocrinal disorder with abnormal apoptotic activity and folliculogenesis. However, the exact effects of Hsp27 downregulation on oocyte development have not yet been clarified.     

Preparation and gas storage of high surface area microporous carbon derived from biomass source cornstalks

Microporous carbon (MC) with a high surface area has been prepared from cornstalks through carbonization and KOH activation. The surface area of the obtained product varies to some extent but the pore size of the material remains within the micropore region as the concentration of KOH activating agent is increased. The MC we prepared exhibits H2 adsorption capacities up to 4.4 wt% at 77K and this material is also able to adsorb considerable amounts of CH4 and CO2. The high adsorption capacities for gases are attributed to the relatively narrow pore size and the high surface area of the porous carbon material.     

Fifteen weeks of dietary n-3 polyunsaturated fatty acid deprivation increase turnover of n-6 docosapentaenoic acid in rat-brain phospholipids

Docosapentaenoic acid (DPAn-6, 22:5n-6) is an n-6 polyunsaturated fatty acid (PUFA) whose brain concentration can be increased in rodents by dietary n-3 PUFA deficiency, which may contribute to their behavioral dysfunction. We used our in vivo intravenous infusion method to see if brain DPAn-6 turnover and metabolism also were altered with deprivation. We studied male rats that had been fed for 15weeks post-weaning an n-3 PUFA adequate diet containing 4.6% alpha-linolenic acid (α-LNA, 18:3n-3) or a deficient diet (0.2% α-LNA), each lacking docosahexaenoic acid (22:6n-3) and arachidonic acid (AA, 20:4n-6). [1-(14)C]DPAn-6 was infused intravenously for 5min in unanesthetized rats, after which the brain underwent high-energy microwaving, and then was analyzed. The n-3 PUFA deficient compared with adequate diet increased DPAn-6 and decreased DHA concentrations in plasma and brain, while minimally changing brain AA concentration. Incorporation rates of unesterified DPAn-6 from plasma into individual brain phospholipids were increased 5.2-7.7 fold, while turnover rates were increased 2.1-4.7 fold. The observations suggest that increased metabolism and brain concentrations of DPAn-6 and its metabolites, together with a reduced brain DHA concentration, contribute to behavioral and functional abnormalities reported with dietary n-3 PUFA deprivation in rodents. (196 words).     

Genome-Wide Transcriptional Response of Silkworm (Bombyx mori) to Infection by the Microsporidian Nosema bombycis

Microsporidia have attracted much attention because they infect a variety of species ranging from protists to mammals, including immunocompromised patients with AIDS or cancer. Aside from the study on Nosema ceranae, few works have focused on elucidating the mechanism in host response to microsporidia infection. Nosema bombycis is a pathogen of silkworm pébrine that causes great economic losses to the silkworm industry. Detailed understanding of the host (Bombyx mori) response to infection by N. bombycis is helpful for prevention of this disease. A genome-wide survey of the gene expression profile at 2, 4, 6 and 8 days post-infection by N. bombycis was performed and results showed that 64, 244, 1,328, 1,887 genes were induced, respectively. Up to 124 genes, which are involved in basal metabolism pathways, were modulated. Notably, B. mori genes that play a role in juvenile hormone synthesis and metabolism pathways were induced, suggesting that the host may accumulate JH as a response to infection. Interestingly, N. bombycis can inhibit the silkworm serine protease cascade melanization pathway in hemolymph, which may be due to the secretion of serpins in the microsporidia. N. bombycis also induced up-regulation of several cellular immune factors, in which CTL11 has been suggested to be involved in both spore recognition and immune signal transduction. Microarray and real-time PCR analysis indicated the activation of silkworm Toll and JAK/STAT pathways. The notable up-regulation of antimicrobial peptides, including gloverins, lebocins and moricins, strongly indicated that antimicrobial peptide defense mechanisms were triggered to resist the invasive microsporidia. An analysis of N. bombycis-specific response factors suggested their important roles in anti-microsporidia defense. Overall, this study primarily provides insight into the potential molecular mechanisms for the host-parasite interaction between B. mori and N. bombycis and may provide a foundation for further work on host-parasite interaction between insects and microsporidia.     

Interactions of some modified mono- and bis-beta-cyclodextrins with bovine serum albumin

Two mono-substituted beta-cyclodextrins and two bridged bis-beta-cyclodextrins, that is, mono(6-(2-aminoethylamino)-6-deoxy)-beta-cyclodextrin (1), mono(6-(2-(2-aminoethylamino)ethylamino)-6-deoxy)-beta-cyclodextrin (2), ethylene-1,2-diamino bis-6-(6-deoxy-beta-cyclodextrin) (3), and iminodiethylene-2,2'-diamino bis-6-(6-deoxy-beta-cyclodextrin) (4), were prepared from beta-cyclodextrin. Their binding ability with bovine serum albumin as a model protein was investigated through proton magnetic resonance (1H NMR), ultraviolet visible spectroscopy (UV-vis), circular dichroism (CD), and fluorescence spectroscopy. In the 1H NMR spectra of the modified cyclodextrins, the resolution of proton signals decreases after the addition of BSA. From the UV and CD spectra, it is found that both the UV absorption and the alpha-helix content of BSA increase with the concentration of the modified cyclodextrins. The protein-ligand interactions cause a fluorescence quenching. The quenching constants are determined using the Stern-Volmer equation to provide an observation of the binding affinity between modified cyclodextrins and BSA. All these results indicate that the modified cyclodextrins can interact with BSA and the bridged bis(beta-cyclodextrin)s (3 and 4) have much stronger interactions than the mono-substituted beta-cyclodextrins (1 and 2). The strong binding stability of bis-cyclodextrins should be attributed to the cooperative effect of two adjacent cyclodextrin moieties. Job's plot shows that the complex stoichiometries of BSA to the modified cyclodextrins were 1:4 for 1 and 2, as well as 1:3 for 3 and 4, respectively.     

Positive identification of the puberty-accelerating pheromone of the house mouse: the volatile ligands associating with the major urinary protein

Five structurally diverse small ligands, all binding to the major urinary protein (MUP) of the male house mouse, show individually puberty-accelerating pheromonal activity in the recipient females. A recombinant MUP (identical structurally to the natural protein) has shown no biological activity. While four of these ligands were previously implicated in oestrus synchronization (Whitten effect), the same chemosignals now appear responsible for both sexual maturation and cycling in adult females.     

A Novel Cationic Ribonuclease with Antimicrobial Activity from Rana dybowskii

A novel ribonuclease (RNase) A superfamily gene (Rdronc) has been cloned from the frog Rana dybowskii. The deduced amino acid sequence shows that it belongs to the ribonuclease A superfamily, with the highest identity, 73%, to Rana pipiens onconase. Adaptive evolution analysis based on maximum likelihood models of codon substitution has been conducted on 10 members of the Rana RNases of subcluster B. Rapid adaptive evolution and multiple positive selection sites have been detected, which indicates that these genes may be evolving under positive selection pressure. Functional assay demonstrates that the recombinant Rdronc protein possesses antimicrobial activity against Gram-negative Escherichia coli and Pseudomonas aeruginosa and weaker antimicrobial activity against Gram-positive Staphylococcus aureus and yeast Candida albicans. Our findings support the hypothesis that ribonuclease A superfamily members may function in host defense of early-diversified vertebrates.