Sulfo-N-succinimidyl esters of long chain fatty acids specifically inhibit fatty acid translocase (FAT/CD36)-mediated cellular fatty acid uptake

Sulfo-N-succinimidyl esters of LCFAs are a powerful tool to investigate the functional significance of plasmalemmal proteins in the LCFA uptake process. This notion is based on the following observations. First, sulfo-N-succinimidyl oleate (SSO) was found to inhibit the bulk of LCFA uptake into various cell types, i.e. rat adipocytes, type II pneumocytes and cardiac myocytes. Second, using cardiac giant membrane vesicles, in which LCFA uptake can be investigated in the absence of mitochondrial -oxidation, SSO retained the ability to largely inhibit LCFA uptake, indicating that inhibition of LCFA transsarcolemmal transport is its primary action. Third, SSO has no inhibitory effect on glucose and octanoate uptake into giant membrane vesicles derived from heart and skeletal muscle, indicating that its action is specific for LCFA uptake. Finally, SSO specifically binds to the 88 kDa plasmalemmal fatty acid transporter FAT, a rat homologue of human CD36, resulting in an arrest of the transport function of this protein.In addition to its inhibitory action at the plasma membrane level, evidence is presented for the lack of a direct inhibitory effect on subsequent LCFA metabolism. First, the relative contribution of oxidation and esterification to LCFA uptake is not altered in the presence of SSO. Second, isoproterenol-mediated channeling of LCFAs into oxidative pathways is not affected by sulfo-N-succinimidyl palmitate (SSP). As an example of its application we used SSP to study the role of FAT/CD36 in contraction- and insulin-stimulated LCFA uptake by cardiac myocytes , showing that this transporter is a primary site of regulation of cellular LCFA utilization.     

Field-based evaluation of biopesticide impacts on native biodiversity: malagasy coleoptera and anti-locust entomopathogenic fungi

A community of 225 species of Coleoptera was used as a surrogate to evaluate nontarget effects of entomopathogenic fungi under development as biopesticides for use against the Malagasy migratory locust Locusta migratoria capito Saussure (Orthoptera: Acrididae). Evaluation of a standard chemical treatment of fenitrothion + esfenvalerate, two indigenous isolates of Metarhiziumflavoviride Gams & Roszsypol (SP3 and SP9), and an indigenous isolate of Beauveria bassiana (Balsamo) Vuillemin (SP16) against an untreated control in a replicated field trial in southern Madagascar showed that one of the isolates of M. flavoviride (SP3) and fenitrothion + esfenvalerate had distinct effects on nontarget beetle communities that were similar to each other. The other two isolates had no detectable effects compared with the untreated control. Based on an evaluation of the species affected, the similar effects of SP3 and the chemical pesticide are hypothesized to be the result of a perturbation of predator-prey relationships, with a distinct tendency to be manifested via predators. The data indicate that use of SP9 and SP16 would have minimal detrimental effects on the biodiversity of nontarget beetles, but that SP3 needs further testing.     

Which genetic loci have greater population assignment power?

SUMMARY: WHICHLOCI is a program that determines the relative discriminatory power of alternate genetic loci and loci combinations for population assignment of individuals. AVAILABILITY: http://www.oregonstate.edu/dept/comes/genetics/software.htm     

Soil-borne <Emphasis Type="Italic">Penicillium</Emphasis> spp. and other microfungi as efficient degraders of the explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine)

Soil microfungi belonging to the genera Aspergillus, Coniothyrium, Paecilomyces, Penicillium and Trichoderma, as well as wood-and litter-decomposing basidiomycetes, were able to degrade the explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) co-metabolically, but were unable to utilize it as a sole carbon or nitrogen source. The most efficient RDX-degrading microfungi were characterized morphologically and by analysis of the ITS region of the ribosomal RNA gene cluster as Penicillium janczewskii and an unidentifiable Penicillium sp. with uniseriate phialides. Both species catalysed 80–100 % disappearance of RDX in a liquid defined medium. RDX degradation was inhibited by the presence of 30 mM NH₄ ⁺ but not by 40 mM NO₃ ⁻. In basidiomycetes but not Penicillium spp., RDX degradation was greatly reduced when biomass pregrown at 23 °C was incubated with RDX at 15 °C. Because of their production of copious conidial inoculum, simple growth requirements and ability to degrade RDX at reduced temperature, Penicillium spp. show promise for the bioremediation of RDX-contaminated groundwater.     

The role of nitrate reductase in the degradation of the explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) by <Emphasis Type="Italic">Penicillium</Emphasis> sp. AK96151

In liquid culture on a defined growth medium, Penicillium sp. AK96151 efficiently degraded the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, hexogen), causing > 80 % disappearance after 10 d. RDX degradation was reduced to a basal level (< 15 % degraded after 10 d) by the presence of > 150 μM ammonium ions or when the molybdenum component of the medium was replaced by sodium tungstate. An equivalent effect of ammonium, molybdenum and tungsten was observed in protoplasts of this fungus assayed for nitrate reductase activity. This enzyme was not inhibited by RDX itself. The involvement of a nitrate reductase in RDX degradation by Penicillium has practical implications for bioremediation strategies which are discussed.     

Purified U7 snRNPs lack the Sm proteins D1 and D2 but contain Lsm10, a new 14 kDa Sm D1-like protein

U7 snRNPs were isolated from HeLa cells by biochemical fractionation, followed by affinity purification with a biotinylated oligonucleotide complementary to U7 snRNA. Purified U7 snRNPs lack the Sm proteins D1 and D2, but contain additional polypeptides of 14, 50 and 70 kDa. Microsequencing identified the 14 kDa polypeptide as a new Sm-like protein related to Sm D1 and D3. Like U7 snRNA, this protein, named Lsm10, is enriched in Cajal bodies of the cell nucleus. Its incorporation into U7 snRNPs is largely dictated by the special Sm binding site of U7 snRNA. This novel type of Sm complex, composed of both conventional Sm proteins and the Sm-like Lsm10, is most likely to be important for U7 snRNP function and subcellular localization.     

Effect of different daytime and night-time temperature regimes on the foliar respiration of Pinus taeda: predicting the effect of variable temperature on acclimation

The objectives of this study were to determine the acclimation of loblolly pine (Pinus taeda L.) foliar respiration to different night-time low temperatures, daytime high temperatures, and daily mean temperatures, and then to use the responses of temperature acclimation to various temperature regimes to predict acclimation under fluctuating temperatures. Experiments were conducted on two-year-old seedlings in growth chambers using different combinations of day and night-time temperatures. The first experiment exposed trees to 22/22, 29/22, 22/15, and 29/15 degrees C day/night (d/n). When measured at a common temperature (15, 22 or 29 degrees C), respiration rates were lower for trees exposed to higher treatment temperatures and acclimation was influenced by both day and night-time temperature. However, the extent of acclimation did not relate to mean temperature, i.e. respiration rates measured at a common temperature ranked as follows for seedlings exposed to different temperature regimes, 22/15>22/22>29/15 congruent with29/22 degrees C d/n. Rather, acclimation of foliar respiration was linearly related to mean daily respiration rate, where mean daily respiration rate is the average of the respiration rates measured at the day and night-time treatment temperatures. The discrepancy between mean daily respiration rate and mean daily temperature occurred because respiration increased exponentially with increasing temperature. In a second experiment, the same seedlings were exposed to 22/22, 15/15, 25.5/18.5, and 25.5/15 degrees C d/n to test the relationship between mean daily respiration rate and acclimation. As in the first experiment, acclimation was linearly related to mean daily respiration rate. The concept of effective acclimation temperature, which is the temperature at which the mean daily respiration rate occurs, was derived from these results as a means to predict the extent that foliar respiration acclimates to treatment temperature.     

Detection of mitogen induced stimulation of leukocytes from the rainbow trout (Oncorhynchus mykiss) by flow cytometric analysis of intracellular calcium

Flow cytometric analysis of the forward/side light scatter (FSC/SSC) of density gradient-separated head kidney cells of the rainbow trout revealed three distinctly separated populations, which we defined as population 1, 2 and 3. In spleen cells, populations 1 and 2 were also found, whereas population 3 was not detected. Further characterization regarding the surface Ig (sIg) revealed that population 2 of the head kidney and spleen contained 37.4 and 34.4% sIg⁺-cells, respectively. Incubation of the head kidney and spleen cells with different concentrations of concanavalin A (ConA), phytohemagglutinin (PHA) and [PWM] induced a pronounced intracellular calcium increase only in cells of population 2. This reaction was concentration dependent and caused by a release of intracellular Ca²⁺-stores. FMLP, a chemotactic peptide, had no effect on intracellular calcium response in all three populations. Similarly, the stimulation with PMA had no effect. This indicates that population 2 of the head kidney as well as the spleen is characterized by a high forward and low side light scatter and contains both subpopulation of lymphocytes, B- and T-cells. We demonstrated that the analysis of intracellular calcium increase due to mitogens is a suitable approach to identify lymphocytes in fish and enables further functional studies in these cells.