Stimulation of the efflux of L-glutamate from renal brush-border membrane vesicles by extravesicular potassium

The rate of efflux of L-glutamate from renal brush-border membrane vesicles was enhanced by Na+ and by extravesicular L-glutamate, but not by D-glutamate nor analogs of L-glutamate that do not share the Na+-L-glutamate co-transport system. These results suggest that efflux was mediated by the Na+-L-glutamate carrier. The efflux of L-glutamate was increased by extravesicular K+ or Rb+ but not by Li+, choline+, or Tris+. These findings, together with previous results showing that intravesicular K+ or Rb+ increased L-glutamate uptake and that a K+ gradient energized the concentrative uptake of the acidic amino acid in the absence of other gradients, provide evidence consistent with the hypothesis that the co-transport of Na+-L-glutamate is coupled to the transmembrane flux of K+.     

IL-28 Supplants Requirement for Treg Cells in Protein σ1-Mediated Protection against Murine Experimental Autoimmune Encephalomyelitis (EAE)

Conventional methods to induce tolerance in humans have met with limited success. Hence, efforts to redirect tolerogen uptake using reovirus adhesin, protein sigma 1 (pσ1), may circumvent these shortcomings based upon the recent finding that when reovirus pσ1 is engineered to deliver chicken ovalbumin (OVA) mucosally, tolerance is obtained, even with a single dose. To test whether single-dose tolerance can be induced to treat EAE, proteolipid protein (PLP_130–151) was genetically fused to OVA to pσ1 (PLP:OVA-pσ1) and shown to significantly ameliorate EAE, suppressing proinflammatory cytokines by IL-10⁺ forkhead box P3 (FoxP3)⁺ CD25⁺CD4⁺ T_reg and IL-4⁺CD25⁻CD4⁺ Th2 cells. IL-10R or IL-4 neutralization reversed protection to EAE conferred by PLP:OVA-pσ1, and adoptive transfer of Ag-specific T_reg or Th2 cells restored protection against EAE in recipients. Upon assessment of each relative participant, functional inactivation of CD25 impaired PLP:OVA-pσ1''s protective capacity, triggering TGF-β-mediated inflammation; however, concomitant inactivation of TGF-β and CD25 reestablished PLP:OVA-pσ1-mediated protection by IL-28-producing FoxP3⁺CD25⁻CD4⁺ T cells. Thus, pσ1-based therapy can resolve EAE independently of or dependently upon CD25 and assigns IL-28 as an alternative therapy for autoimmunity.     

Positive health: connecting well-being with biology

Two key types of well-being, eudaimonic and hedonic, are reviewed. The first addresses ideas of self-development, personal growth and purposeful engagement, while the second is concerned with positive feelings such as happiness and contentment. How well-being varies by age and socio-economic standing is briefly summarized, followed by examination of its biological correlates (neuroendocrine, immune, cardiovascular, rapid eye movement (REM) sleep). Preliminary findings on a sample of ageing women showed that those with higher levels of eudaimonic well-being had lower levels of daily salivary cortisol, pro-inflammatory cytokines, cardiovascular risk, and longer duration REM sleep compared with those showing lower levels of eudaimonic well-being. Hedonic well-being, however, showed minimal linkage to biomarker assessments. Future research directions building on these initial findings are discussed.     

Synthesis and biological activity of selective pipecolic acid-based TNF-alpha converting enzyme (TACE) inhibitors

A series of novel, selective TNF-alpha converting enzyme inhibitors based on 4-hydroxy and 5-hydroxy pipecolate hydroxamic acid scaffolds is described. The potency and selectivity of TACE inhibition is dramatically influenced by the nature of the sulfonamide group which interacts with the S1' site of the enzyme. Substituted 4-benzyloxybenzenesulfonamides exhibit excellent TACE potency with >100x selectivity over inhibition of matrix metalloprotease-1 (MMP-1). Alkyl substituents on the ortho position of the benzyl ether moiety give the most potent inhibition of TNF-alpha release in LPS-treated human whole blood.     

Seroprevalence of Trypanosoma cruzi in raccoons from South Carolina and Georgia

Trypanosoma cruzi, the causative agent of American trypanosomiasis or Chagas' disease, is of both medical and veterinary importance as is evidenced by chronic phase myocarditis in humans and dogs. Further, T. cruzi has been reported from over 20 species of wildlife reservoir hosts in the USA, with raccoons (Procyon lotor) and opossums (Didelphis virginiana) being the most common. Whereas previous studies on T. cruzi in raccoons have included only culture and direct examination of blood, the indirect immunofluorescent antibody test (IFAT) was used in the current study to detect anti-T. cruzi antibodies in the serum of raccoons. Of 221 raccoons trapped at 13 sites representing the five physiographic regions of South Carolina plus five sites in the Piedmont region of Georgia (from April 1997 to February 2000), 104 (47%) were seropositive. A higher seroprevalence in raccoons was observed in the coastal regions, with seroprevalence in the Lower Coastal Plain South (61%) being significantly higher than that in the Foothills (37%), Piedmont (42%), and Upper Coastal Plain (40%) regions. However, at a seroprevalence of 52%, the Lower Coastal Plain North was not significantly different from any other region. Although more female raccoons were infected than males, no statistical difference in prevalence was observed between sexes. The high seroprevalence of T. cruzi in raccoons, together with a few reports of wildlife isolates being infective for other wildlife species and domestic/laboratory animals, suggests that risk of T. cruzi infection may be higher than previously suspected.     

Genetic diversity and population structure in Malus sieversii, a wild progenitor species of domesticated apple

Malus sieversii (Lebed.) M. Roem. is a wild progenitor species of the domesticated apple. It is found across a mountainous region of central Asia and has been the focus of several collection expeditions by the USDA-ARS-National Plant Germplasm System. This study used microsatellite variation at seven loci to estimate diversity and differentiation within M. sieversii using several complimentary approaches. Multilocus genotypes were amplified from 949 individuals representing seedling trees from 88 half-sib families from eight M. sieversii populations collected in Kazakhstan. Apportioning of genetic variation was estimated at both the family and site level. Analyses using a hierarchical model to estimate F _st showed that differentiation among individual families is more than three times greater than differentiation among sites. In addition, average gene diversity and allelic richness varied significantly among sites. A rendering of a genetic network among all sites showed that differentiation is largely congruent with geographical location. In addition, nonhierarchical Bayesian assignment methods were used to infer genetic clusters across the collection area. We detected four genetic clusters in the data set. The quality of these assignments was evaluated over multiple Markov Chain Monte Carlo runs using both posterior likelihood and stability of the assignments. The spatial pattern of genetic assignments among the eight collection sites shows two broadly distributed and two narrowly distributed clusters. These data indicate that the southwestern collection sites are more admixed and more diverse than the northern sites.     

Bead rings at the endoplasmic reticulum-golgi complex boundary: morphological changes accompanying inihibition of intracellular transport of secretory proteins in arthropod fat body tissue

Golgi complex beads are 10-nm particles arranged in rings on the smooth surface of rough endoplasmic reticulum (ER) makind the forming face of the Golgi complex (GC). In arthropod cells they stain specifically with bismuth. Their morphology has been studied after treatment with reagents known to interfere with GC function. Inhibitors of oxidative phosphorylation (antimycin A, cyanide, and anoxia), but not an inhibitor of glycolysis (iodoacetate), both cause the bead rings to collapse and the GC saccules to round up, and inhibit transition vesicle (TV) formation. Cycloheximide blocks protein synthesis on ribosomes but does not stop TV formation or disrupt bead rings, even after prolonged treatment (6 h) to allow emptying of the rough ER cisternae. Thus the collapse of bead rings is not attributable to inhibition of protein synthesis, and the ring structure of beads does not require continued protein synthesis and secretion for its maintenance. Valinomycin has effects on the GC similar to those of antimycin A, but {"type":"entrez-nucleotide","attrs":{"text":"A23187","term_id":"833253","term_text":"A23187"}}A23187, monensin, and lasalocid do not affect bead ring structure or TV formation. These results are consistent with valinomycin’s secondarily uncoupling mitochondria, which collapses bead rings and prevents TV formation. Thus inhibitors of oxidative phosphorylation do not influence the beads through cation movement. Because mononsin and lasalocid block secretion at the level of the condensing vacuoles, bead rings are not influenced by blocks in secretion distal to them or by the backup of secretory material. These experiments are consistent with inhibitors of oxidative phosphorylation collapsing bead rings by decreasing intracellular ATP. The concomitant block to TV formation and the collapse of bead rings suggests that integrity of the bead rings is essential for the transport of secretory material from the rough ER to the GC.     

Identification of stable fly attractant compounds in vinasse,a byproduct of sugarcane–ethanol distillation

The stable fly, Stomoxys calcitrans (Diptera: Muscidae), is a worldwide pest of livestock. Recent outbreaks of stable flies in sugarcane fields in Brazil have become a serious problem for livestock producers. Larvae and pupae found inside sugarcane stems after harvesting may indicate that stable flies use these stems as potential oviposition or larval development sites. Field observations suggest that outbreaks of stable flies are associated with the vinasse and filter cake derived from biomass distillation in sugarcane ethanol production that are used as fertilizers in sugarcane fields. Adult stable flies are attracted to vinasse, which appears to present an ideal larval development site. The primary goal of the present study is to demonstrate the role of vinasse in influencing the sensory physiological and behavioural responses of stable flies, and to identify its associated volatile attractant compounds. Both laboratory and field studies showed that vinasse is extremely attractive to adult stable flies. Chemical analyses of volatiles collected revealed a wide range of carboxylic acids, alcohols, phenols and aldehydes as potential attractant compounds. These newly identified attractants could be used to develop a tool for the attractant‐baited mass trapping of stable flies in order to reduce infestations.     

基于钙黄绿素- 铜(Ⅱ)荧光体系测定乙酰半胱氨酸

目的:基于钙黄绿素-铜(Ⅱ)荧光体系测定乙酰半胱氨酸。方法:在pH=8.0的Na2HPO.412H2O-KH2PO4缓冲液中,以492 nm为激发波长,520 nm为发射波长测定乙酰半胱氨酸溶液的荧光强度。结果:在pH=8.0的Na2HPO.412H2O-KH2PO4缓冲液中,二价铜离子与钙黄绿素配位引起荧光猝灭。由于乙酰半胱氨酸中巯基上的硫离子与Cu2+的亲和力很强,可从钙黄绿素-铜(Ⅱ)的络合物中夺取铜离子而使钙黄绿素游离出来,从而使体系的荧光得以恢复,并且荧光恢复的程度与加入乙酰半胱氨酸的量在一定范围内成线性。结论:建立了一种测定乙酰半胱氨酸的荧光分析新方法,该方法的线性范围为6.0 10-6～1.4 10-5 mol/L,检出限为4.010-6 mol/L。