Bactericidal but not nonbactericidal C5b-9 is associated with distinctive outer membrane proteins in Neisseria gonorrhoeae

In this study, we examined the bacterial constituents associated with the complement C5b-9 complex in detergent extracts from serum-treated Neisseria gonorrhoeae (GC). 125I surface-labeled GC were incubated in 10% serum, were washed, and were solubilized in the zwitterionic sulfobetaine detergent SB12. Immunoprecipitation of 125I-GC from the extract with anti-C5 Sepharose was followed by 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis autoradiography of immunoprecipitated material. Polyacrylamide gel analysis of surface-labeled 125I-GC showed prominent bands for proteins I and III for both serum-resistant GC strain 6305 and serum-sensitive GC strain 7189. These same bands were visible with similar intensity in the SB12 extracts from presensitized and non-presensitized 6305 and 7189 after serum incubation. For those organisms bearing bactericidal C5b-9 (6305 + IgG and 7189 +/- IgG), additional distinctive bands immunoprecipitated with antibody to C5 Sepharose. These components were of 93,000, 44,000 40,000, and 15,000 daltons for 6305 + IgG, and were of 90,000, 50,000, 44,000, and 19,000 daltons for 7189 +/- IgG. Nonbactericidal C5b-9 extracted from the surface of 6305 incubated in serum, but not sensitized with antibody, was not associated with these distinctive proteins. However, this nonbactericidal C5b-9 did have a different pattern of associated bacterial surface constituents from that observed in control samples incubated with antibody to human serum albumin, which were similar to those with nonserum-incubated organisms. These studies support our earlier experiments which demonstrated that C5b-9 is in a different molecular configuration on the surface of serum-resistant GC from that on the surface of serum-sensitive GC or resistant GC rendered sensitive with bactericidal antibody.     

Serotonin-induced disruption of implantation in the rat: II. Suppression of decidualization

Subcutaneous injection of serotonin (20 mg/kg) on Day 5 of pregnancy disrupts implantation in the rat as indicated by the reduction in number of live fetuses/cornu present on Day 19 (0.9 vs. 6.1, treated vs. control). Such disruption of implantation possibly results from impaired decidualization. To test for suppression of decidualization, serotonin was administered to pseudopregnant rats on the day before, on (Day 4) or after artificial induction of the decidual cell reaction. Relative to saline-treated controls (C), serotonin (S) reduced decidualization when injected either before [C: 1987 +/- 130 vs. S: 1085 +/- 155 mg (Day 3); P less than 0.005] or after [C: 1987 +/- 130 vs. S: 173 +/- 8 mg (Day 5); P less than 0.001] administration of the deciduogenic stimulus. In addition, serotonin markedly decreased uterine blood flow (C: 0.47 +/- 0.05 vs. S: 0.25 +/- 0.06 ml/min per g; P less than 0.01) during pseudopregnancy. However, serotonin altered neither the duration of luteal function in pseudopregnant rats (C: 15.3 vs. S: 14.3 days) nor serum progesterone levels (C: 74-91 vs. S: 53-82 ng/ml) in pregnant animals. It is concluded that serotonin may disrupt implantation, in part, by suppression of decidualization. The loss of endometrial competence to undergo decidualization appears to be a consequence of serotonin-induced uterine ischemia rather than impaired corpus luteum activity.     

Sulphamerazine toxicity in cut-throat trout broodfish Salmo clarki (Richardson)

Treatment of cut-throat trout broodfish Salmo clarki (Richardson) with Sulphamerazine at 220 mg/kg (10 g/100 1b) of fish/day for 14 days resulted in severe kidney histopathology and increased mortality among males. Experimental data presented showed that cut-throat trout broodfish were extremely sensitive to Sulphamerazine toxicity. Hydropic degeneration of renal tubule epithelium and haemorrhage into tubule lumens were observed in kidneys of both male and female trout, but was more severe in the former. Death, which occurred only in males, was correlated with spawning stress and impaired renal function.     

Thrombocyte substitution in acute leukemia. Effect of histocompatibility on the clinical efficacy

Thrombocyte substitution is an essential prerequisite for intensive cytoreductive therapy in acute leukemia. Evaluating 228 thrombocyte transfusions in 17 patients shows that the clinical effectiveness of thrombocyte concentrates can be increased by making the coordination of HLA antigens of donor and receiver as good as possible. When measured in the corrected increment (CI) 24 hours after transfusion, the effectiveness of A3/B1 match preparations (CI = 7.0 +/- 1.6) is significantly higher than that of random preparations (CI = 3.0 +/- 0.5). With the presence of HLA antibodies an effective substitution (CI24 greater than or equal to 4.5) can only be achieved by A3/B1 match thrombocytes. This can only be realized by applying the fourfold thrombapheresis of single donors.     

LDL receptor-related protein internalizes and degrades uPA-PAI-1 complexes and is essential for embryo implantation.

The low density lipoprotein receptor-related protein (LRP) is a large multifunctional clearance receptor that has been implicated in the hepatic uptake of chylomicron remnants and in the removal of protease-inhibitor complexes from the circulation and from the extracellular space. Disruption of the LRP gene in mice blocks development of LRP-/- embryos around the implantation stage. The expression pattern of LRP in the postimplantation stage embryo is identical to that of urokinase, a plasminogen activator that confers invasive properties to migrating cells. We demonstrate that LRP mediates uptake and degradation of urokinase-type plasminogen activator-plasminogen activator inhibitor 1 complexes and propose that the inability of the giant cells to remove the inactive protease complexes from their surfaces interferes with implantation of the embryo.     

The Chlorite Dismutase (HemQ) from Staphylococcus aureus Has a Redox-sensitive Heme and Is Associated with the Small Colony Variant Phenotype

The chlorite dismutases (C-family proteins) are a widespread family of heme-binding proteins for which chemical and biological roles remain unclear. An association of the gene with heme biosynthesis in Gram-positive bacteria was previously demonstrated by experiments involving introduction of genes from two Gram-positive species into heme biosynthesis mutant strains of Escherichia coli, leading to the gene being renamed hemQ. To assess the gene product''s biological role more directly, a Staphylococcus aureus strain with an inactivated hemQ gene was generated and shown to be a slow growing small colony variant under aerobic but not anaerobic conditions. The small colony variant phenotype is rescued by the addition of exogenous heme despite an otherwise wild type heme biosynthetic pathway. The ΔhemQ mutant accumulates coproporphyrin specifically under aerobic conditions. Although its sequence is highly similar to functional chlorite dismutases, the HemQ protein has no steady state reactivity with chlorite, very modest reactivity with H₂O₂ or peracetic acid, and no observable transient intermediates. HemQ''s equilibrium affinity for heme is in the low micromolar range. Holo-HemQ reconstituted with heme exhibits heme lysis after <50 turnovers with peroxide and <10 turnovers with chlorite. The heme-free apoprotein aggregates or unfolds over time. IsdG-like proteins and antibiotic biosynthesis monooxygenases are close sequence and structural relatives of HemQ that use heme or porphyrin-like organic molecules as substrates. The genetic and biochemical data suggest a similar substrate role for heme or porphyrin, with possible sensor-regulator functions for the protein. HemQ heme could serve as the means by which S. aureus reversibly adopts an SCV phenotype in response to redox stress.     

Aspects of floral structure and phenology in the genusConophytum (Mesembryanthemaceae)

The complex floral structure in the southern African genusConophytum (Mesembryanthemaceae; 77 spp.) is described in detail and assigned to three basic floral types, two of which can be divided into two subtypes. Correlations between structural features and phenological patterns are demonstrated and discussed in the family context as well as in relation to the systematic subdivision of the genus.