Effects of lead and cadmium on chemical composition and total water content of the pupal parasitoid, Pimpla turionellae

The parasitoid Pimpla turionellae L. (Hymenoptera, Ichneumonidae) was fed on Cd, Pb and Cd+Pb-contaminated food (33g Cd, 82g Pb and 33g Cd+82g Pb per gram food fresh weight, respectively). Significant decrease in the total lipid and protein content was found along with an increase in the water content particularly in Cd-contaminated parasitoids.     

Expression and characterization of recombinant human factor V and a mutant lacking a major portion of the connecting region

Human coagulation factor V is a protein cofactor that is an essential component of the prothrombinase complex. A full-length factor V cDNA has been subcloned into the mammalian expression vector pDX and used to transfect COS cells. Approximately 95 +/- 4% of the recombinant human factor V (rHFV) synthesized in COS cells is secreted into the culture medium. Forty-eight hours after transfection rHFV antigen levels in the conditioned medium were 70 +/- 15 ng/mL. Factor V activity determined by fibrometer assay increased approximately 5-fold from 0.027 +/- 0.012 to 0.124 +/- 0.044 unit/mL following activation by the factor V activating enzyme from Russell's viper venom (RVV-V). A chromogenic assay specific for factor Va indicated that recombinant factor V had 3.8 +/- 1.3% of the activity of the activated protein. The estimated specific activity of the recombinant factor Va was approximately 1800 +/- 500 units/mg, which is similar to the specific activity of purified plasma factor Va of 1700-2000 units/mg. Immunoprecipitation of [35S]methionine-labeled rHFV revealed a single high molecular mass component (approximately 330 kDa). Treatment of rHFV with thrombin or RVV-V resulted in the formation of proteolytic products that were similar to those seen with plasma factor V. We have also expressed a mutant, rHFV-des-B811-1441, that lacks a large portion of the highly glycosylated connecting region that is present in factor V. Immunoprecipitation of [35S]methionine-labeled rHFV-des-B811-1441 revealed a single-chain polypeptide with Mr approximately 230 kDa. This mutant constitutively expressed 38 +/- 7% of the activity of the RVV-V-activated protein.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of oxytetracycline and erythromycin on Syrian hamsters after intratracheal infection with Mycoplasma pneumoniae

Male Syrian hamsters were infected intratracheally with Mycoplasma pneumoniae and treated here after for ten days with either OTC or erythromycin. The purpose of this study was to investigate whether there exists a relation between the persistence of M. pneumoniae in the lungs and the infection dose respectively the days passed after infection before starting treatment with antibiotics. The influence of antibiotic therapy on the immune response of the hamsters was also investigated.     

Identification of MarvelD3 as a tight junction-associated transmembrane protein of the occludin family

Background

Protein translocation across the membrane of the Endoplasmic Reticulum (ER) is the first step in the biogenesis of secretory and membrane proteins. Proteins enter the ER by the Sec61 translocon, a proteinaceous channel composed of three subunits, α, β and γ. While it is known that Sec61α forms the actual channel, the function of the other two subunits remains to be characterized.

Results

In the present study we have investigated the function of Sec61β in Drosophila melanogaster. We describe its role in the plasma membrane traffic of Gurken, the ligand for the Epidermal Growth Factor (EGF) receptor in the oocyte. Germline clones of the mutant allele of Sec61β show normal translocation of Gurken into the ER and transport to the Golgi complex, but further traffic to the plasma membrane is impeded. The defect in plasma membrane traffic due to absence of Sec61β is specific for Gurken and is not due to a general trafficking defect.

Conclusion

Based on our study we conclude that Sec61β, which is part of the ER protein translocation channel affects a post-ER step during Gurken trafficking to the plasma membrane. We propose an additional role of Sec61β beyond protein translocation into the ER.     

Sequence of a cDNA for mouse thymidylate synthase reveals striking similarity with the prokaryotic enzyme

We report the nucleotide sequence of a cloned cDNA, pMTS-3, that contains a 1-kb insert corresponding to mouse thymidylate synthase (E.C. 2.1.1.45). The open reading frame of 921 nucleotides from the first AUG to the termination codon specifies a protein with a molecular mass of 34,962 daltons. The predicted amino acid sequence is 90% identical with that of the human enzyme. The mouse sequence also has an extremely high degree of similarity (as much as 55% identity) with prokaryotic thymidylate synthase sequences, indicating that thymidylate synthase is among the most highly conserved proteins studied to date. The similarity is especially pronounced (as much as 80% identity) in the 44-amino-acid region encompassing the binding site for deoxyuridylic acid. The cDNA sequence also suggests that mouse thymidylate synthase mRNA lacks a 3' untranslated region, since the termination codon, UAA, is followed immediately by a poly(A) segment.      

Blockade of tissue factor-factor X binding attenuates sepsis-induced respiratory and renal failure

Tissue factor expression in sepsis activates coagulation in the lung, which potentiates inflammation and leads to fibrin deposition. We hypothesized that blockade of factor X binding to the tissue factor-factor VIIa complex would prevent sepsis-induced damage to the lungs and other organs. Acute lung injury was produced in 15 adult baboons primed with killed Escherichia coli [1 x 10(9) colony-forming units (CFU)/kg], and then 12 h later, they were given 1 x 10(10) CFU/kg live E. coli by infusion. Two hours after live E. coli, animals received antibiotics with or without monoclonal antibody to tissue factor intravenously to block tissue factor-factor X binding. The animals were monitored physiologically for 34 h before being killed and their tissue harvested. The antibody treatment attenuated abnormalities in gas exchange and lung compliance, preserved renal function, and prevented tissue neutrophil influx and bowel edema relative to antibiotics alone (all P < 0.05). It also attenuated fibrinogen depletion (P < 0.01) and decreased proinflammatory cytokines, e.g., IL-6 and -8 (P < 0.01), in systemic and alveolar compartments. Similar protective effects of the antibody on IL-6 and -8 expression and permeability were found in lipopolysaccharide-stimulated endothelial cells. Blockade of factor X binding to the tissue factor-factor VIIa complex attenuates lung and organ injuries in established E. coli sepsis by attenuating the neutrophilic response and inflammatory pathways.