Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Circulating phagocytic cells (hemocytes) of the snail Biomphalaria glabrata, intermediate host of the human blood fluke Schistosoma mansoni, were treated with the tetrapeptide, arg-gly-asp-ser (RGDS), an integrin-specific adhesion inhibitor, and assessed for their ability to adhere and spread on uncoated and snail plasma protein-coated glass slides. Although cells were capable of adherence, RGDS significantly inhibited the spreading ability of hemocytes in both a time and RGDS concentration-dependent fashion regardless of plasma protein coating. The inhibition of hemocyte spreading by RGDS was a specific response, since treatment of cells with a glutamic acid-substituted control peptide (RGES) did not exert the same inhibitory effect. A comparison of RGDS-responses between hemocytes of two strains of B. glabrata, one resistant (R; 13-16-R1 strain) and the other susceptible (S; NMRI strain) to infection by S. mansoni, revealed several snail strain-specific differences. At concentrations of 0.5 mM RGDS, R snail hemocyte spreading was unaffected, whereas a significant depression of spreading was seen in cells of the S snail. Moreover, we observed that R strain hemocytes spread more rapidly on homologous plasma-coated surfaces than the S snail strain following peptide pretreatment and removal. These data suggest that hemocytes from S and R snails may differ either in the number of RGDS-binding receptors or in their affinity for the RGDS peptide. In order to identify the type(s) of integrin-like RGD-binding receptors that may be present on the surface of snail immunocytes, washed hemocytes were placed on various mammalian extracellular matrix proteins and evaluated for their spreading function in the presence of specific or non-specific peptides. Hemocyte aggregation or clumping was observed on all test protein substrates, and this aggregation behavior was specifically inhibited by RGDS. Thus, RGD-binding receptors appear to play a critical role in cellular motility on matrix-coated surfaces and/or cell-cell binding. Our data provide functional evidence for an integrin-like receptor on circulating phagocytes of snails, and for an RGD-binding mechanism involved in cell-substrate interactions.
 ...
PMID:Integrin-like RGD-dependent binding mechanism involved in the spreading response of circulating molluscan phagocytes. 961 82

The mode of reproduction (sexual and/or asexual) and the mating system determine the patterns of gene transmission and genotype formation across generations. Schistosoma mansoni is a dioecious trematode that necessarily alternates sexual and asexual reproduction during its life cycle. In a previous study of the distribution of S. mansoni genetic variability within and between definitive host individuals, we noticed that deleting multilocus genotypes from each infrapopulation so as to keep only one copy of each multilocus genotype, seemed to have a substantial effect on FIS values. More precisely, female FIS increased when repeated genotypes were removed whereas no effect was observed on male FIS. This suggested that multilocus genotypes at high frequency tended to be more heterozygous. The aim of the present study is specifically to test and analyse this phenomenon. We demonstrate that the number of repetitions per clone correlates with individual heterozygosity. This effect is however, sex-specific: only female clone size correlates with heterozygosity. We discuss this phenomenon in relation to the heterozygosity-fitness relationship and the sex-specific response to inbreeding depression.
 ...
PMID:Sex-specific correlation between heterozygosity and clone size in the trematode Schistosoma mansoni. 1531 96

In this study, we investigated the expression and activity of liver cytochrome P450s (CYPs) and praziquantel (PZQ) kinetics in mice infected with Schistosoma mansoni. Swiss Webster (SW) mice of both genders were infected (100 cercariae) on postnatal day 10 and killed on post-infection days (PIDs) 30 or 55. Non-infected mice of the same age and sex served as controls. Regardless of mouse sex, infection depressed the activities of CYP1A [ethoxy/methoxy-resorufin-O-dealkylases (EROD/MROD)], 2B9/10 [pentoxy/benzyloxy-resorufin-O-dealkylases (PROD, BROD)], 2E1 [p-nitrophenol-hydroxylase (PNPH)] and 3A11 [erythromycin N-demethylase (END)] on PID 55 but not on PID 30. On PID 55, infection decreased liver CYP mRNA levels (real-time reverse transcription-polymerase chain reaction). On PID 30, whereas mRNA levels remained unaltered in males, they were depressed in females. Plasma PZQ (200 and 400 mg/kg body weight intraperitoneally) levels were measured (high-performance liquid chromatography) at different post-treatment intervals. In males and females, infection delayed the PZQ clearance on PID 55, but not on PID 30. Therefore, it can be concluded that schistosomiasis down-modulated CYP expression and activity and delayed PZQ clearance on PID 55, when a great number of parasite eggs were lodged in the liver. On PID 30, when egg-laying was initiated by the worms, no change of CYP expression and activity was found, except for a depression of CYP1A2 and 3A11 mRNAs in female mice.
 ...
PMID:Modulation of expression and activity of cytochrome P450s and alteration of praziquantel kinetics during murine schistosomiasis. 2153 83


<< Previous 1 2