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21.
Gail Kratzberg 《Journal of Aquatic Ecosystem Stress and Recovery (Formerly Journal of Aquatic Ecosystem Health)》1992,1(4):319-328
The current recognition that chemical measurements are uncertain indicators of biological consequences of pollution has shifted the emphasis away from assessing environmental chemistry alone toward the inclusion of measurements of the health of organisms. Effects of pollutants begin with the individual, have subsequent repercussions on population level processes, and ramifications for community structure and functions. Pollutants act at a molecular level and the biochemical lesions is the first step in the manifestation of effects. Technologies that operate at the cellular level assist in elucidating toxicity. Higher levels of integration include an organism's capacity for growth. Laboratory bioassays andin situ research can monitor physiological incapacities and assist in predicting population level effects. A yet higher level of organization is that of the ecological community. 相似文献
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Thomas P. Zimmerman Claus J. Schmitges Gerald Wolberg Robert D. Deeprose Gail S. Duncan 《Life sciences》1981,28(6):647-652
5'-Deoxy-5'-S-isobutylthioadenosine (SIBA), a synthetic analogue of S-adenosylhomocysteine, has been reported by others to inhibit a number of biological processes and these effects of SIBA have been attributed generally to inhibition of methyltransferases. However, the present studies with mouse lymphocytes show that SIBA also acts as a competitive inhibitor (Ki = 130 μM) of the high-affinity cyclic AMP phosphodiesterase and potentiates the cyclic AMP response of intact cells to several activators of adenylate cyclase. Moreover, SIBA has been found to inhibit lymphocyte-mediated cytolysis, a cellular function known to be sensitive to elevated lymphocyte levels of cyclic AMP, at concentrations (IC50 = 250 μM) similar to those which inhibit cyclic AMP phosphodiesterase. These results indicate the need for caution in attributing biological effects of SIBA singularly to inhibition of methyltransferases and suggest the possible agency of cyclic AMP in the mechanism of SIBA action. 相似文献
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Gail E. Farlow 《International journal for parasitology》1976,6(6):513-516
Babesia rodhaini was less infective to mice after incubation in rat serum than in rat plasma. This was explained by lower levels of glucose in serum than in plasma. Both serum and plasma were found to become metabolically depleted of glucose following prolonged contact with clotted and unclotted blood cells, respectively. When glucose concentrations in depleted samples were restored to those in freshly separated samples, infectivities of parasites were similar. This was shown for both B. rodhaini and B. argentina. Products of blood cell metabolism, produced when separation of plasma or serum was delayed for 24 h, were not shown to have any detrimental effects on the parasites. Average glucose values for plasma from rats and cattle were 153 mg/100 ml and 63 mg/100 ml, respectively, whereas serum and plasma remaining in contact with blood cells contained as little as 2 mg glucose/100 ml. Lactate values were correspondingly low in plasma and high in serum. Fibrinogen and platelets, factors involved in clotting, did not affect infectivity of B. rodhaini or B. argentina. The relevance of these findings to living babesial vaccines in which plasma- and serum-based diluents may be used is discussed. 相似文献
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Andrea M. Price Vera Pospelova Michael R. S. Coffin James S. Latimer Gail L. Chmura 《Ecology and evolution》2016,6(16):5648-5662
Few biogeographic studies of dinoflagellate cysts include the near‐shore estuarine environment. We determine the effect of estuary type, biogeography, and water quality on the spatial distribution of organic‐walled dinoflagellate cysts from the Northeast USA (Maine to Delaware) and Canada (Prince Edward Island). A total of 69 surface sediment samples were collected from 27 estuaries, from sites with surface salinities >20. Dinoflagellate cysts were examined microscopically and compared to environmental parameters using multivariate ordination techniques. The spatial distribution of cyst taxa reflects biogeographic provinces established by other marine organisms, with Cape Cod separating the northern Acadian Province from the southern Virginian Province. Species such as Lingulodinium machaerophorum and Polysphaeridinium zoharyi were found almost exclusively in the Virginian Province, while others such as Dubridinium spp. and Islandinium? cezare were more abundant in the Acadian Province. Tidal range, sea surface temperature (SST), and sea surface salinity (SSS) are statistically significant parameters influencing cyst assemblages. Samples from the same type of estuary cluster together in canonical correspondence analysis when the estuaries are within the same biogeographic province. The large geographic extent of this study, encompassing four main estuary types (riverine, lagoon, coastal embayment, and fjord), allowed us to determine that the type of estuary has an important influence on cyst assemblages. Due to greater seasonal variations in SSTs and SSSs in estuaries compared to the open ocean, cyst assemblages show distinct latitudinal trends. The estuarine context is important for understanding present‐day species distribution, the factors controlling them, and to better predict how they may change in the future. 相似文献
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Han S Guthridge JM Harley IT Sestak AL Kim-Howard X Kaufman KM Namjou B Deshmukh H Bruner G Espinoza LR Gilkeson GS Harley JB James JA Nath SK 《PloS one》2008,3(3):e0001757
Osteopontin (SPP1) is an important bone matrix mediator found to have key roles in inflammation and immunity. SPP1 genetic polymorphisms and increased osteopontin protein levels have been reported to be associated with SLE in small patient collections. The present study evaluates association between SPP1 polymorphisms and SLE in a large cohort of 1141 unrelated SLE patients [707 European-American (EA) and 434 African-American (AA)], and 2009 unrelated controls (1309 EA and 700 AA). Population-based case-control association analyses were performed. To control for potential population stratification, admixture adjusted logistic regression, genomic control (GC), structured association (STRAT), and principal components analysis (PCA) were applied. Combined analysis of 2 ethnic groups, showed the minor allele of 2 SNPs (rs1126616T and rs9138C) significantly associated with higher risk of SLE in males (P = 0.0005, OR = 1.73, 95% CI = 1.28-2.33), but not in females. Indeed, significant gene-gender interactions in the 2 SNPs, rs1126772 and rs9138, were detected (P = 0.001 and P = 0.0006, respectively). Further, haplotype analysis identified rs1126616T-rs1126772A-rs9138C which demonstrated significant association with SLE in general (P = 0.02, OR = 1.30, 95%CI 1.08-1.57), especially in males (P = 0.0003, OR = 2.42, 95%CI 1.51-3.89). Subgroup analysis with single SNPs and haplotypes also identified a similar pattern of gender-specific association in AA and EA. GC, STRAT, and PCA results within each group showed consistent associations. Our data suggest SPP1 is associated with SLE, and this association is especially stronger in males. To our knowledge, this report serves as the first association of a specific autosomal gene with human male lupus. 相似文献
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Rabbit kidney function was assessed in vitro after cryoprotection with either 3 or 4 M dimethyl sulfoxide. The introduction and removal of the cryoprotectant was carried out in a stepwise progressive manner and the removal in a stepwise progressive manner with hypertonic mannitol solutions. This in vitro model can be shown to respond to various ischemic-like states resulting in poor or absent function. Active tubular transport can be demonstrated. It has been used by many authors as an intermediate step prior to the ultimate test of reimplant and contralateral nephrectomy. Variations in the rate of cooling at cryoprotection levels of 3 and 4 M dimethyl sulfoxide concentration (Me2SO) were carried out. In general, at 3 M concentration of Me2SO, creatinine clearance, sodium and glucose reabsorption are preserved with a fair degree of success after cooling to -10, -15, and -20 degrees C in our model, when the rate of cooling to these levels is 1.0 degree C/min. When a cooling rate of 0.5 degree C/min is used, renal function is significantly reduced whether the final temperature is -10, -15, or -20 degrees C. Control rabbit kidneys will tolerate 4 M concentration of Me2SO and give fairly good function. When cooled to -15 or -20 degrees C, there is poor function at 0.1 and 0.5 degrees C/min. Fair function is obtained at the rate of 1 degree C/min to -10 degrees C. Therefore, at cryoprotectant levels of 3 and 4 M Me2SO, kidney function as assayed by in vitro perfusion, is better when the cooling rate is 1.0 degree C/min. 相似文献
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