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81.
Siwi P. M. Wijayanti Sunaryo Sunaryo Suprihatin Suprihatin Melanie McFarlane Stephanie M. Rainey Isabelle Dietrich Esther Schnettler Roman Biek Alain Kohl 《PLoS neglected tropical diseases》2016,10(3)
BackgroundNo vaccine is currently available for dengue virus (DENV), therefore control programmes usually focus on managing mosquito vector populations. Entomological surveys provide the most common means of characterising vector populations and predicting the risk of local dengue virus transmission. Despite Indonesia being a country strongly affected by DENV, only limited information is available on the local factors affecting DENV transmission and the suitability of available survey methods for assessing risk.Conclusions/significanceOur data suggested that the utility of traditional larvae indices, which continue to be used in many dengue endemic countries, should be re-evaluated locally. The results highlight the need for validation of risk indicators and control strategies across DENV affected areas here and perhaps elsewhere in SE Asia. 相似文献
82.
Pre-zygotic isolation is often maintained by species-specific signals and preferences. However, in species where signals are learnt, as in songbirds, learning errors can lead to costly hybridization. Song discrimination expressed during early developmental stages may ensure selective learning later in life but can be difficult to demonstrate before behavioural responses are obvious. Here, we use a novel method, measuring changes in metabolic rate, to detect song perception and discrimination in collared flycatcher embryos and nestlings. We found that nestlings as early as 7 days old respond to song with increased metabolic rate, and, by 9 days old, have increased metabolic rate when listening to conspecific when compared with heterospecific song. This early discrimination between songs probably leads to fewer heterospecific matings, and thus higher fitness of collared flycatchers living in sympatry with closely related species. 相似文献
83.
I.D. McFarlane G.A.B. Shelton 《Journal of experimental marine biology and ecology》1975,19(2):177-186
Phase contrast microscopy and scanning electron microscopy show that during the response of the symbiotic sea anemone Calliactis parasitica (Couch) to shells of Buccinum undatum (L.) three times as many spirocysts as nematocysts are discharged. Observations indicate that spirocysts are responsible for the adhesion of tentacles to shells.Discharge levels are not significantly influenced by the nature of the substratum to which the anemones are attached. The reported observation that fewer tentacles adhere to shells when anemones are settled on shells than when they are fixed on a different substratum is re-interpreted in terms of a new model for the control of spirocyst discharge. 相似文献
84.
Properties of the transfer ribonucleic acid methylase activity in vitro of hamster tumours induced by adenovirus-12. Base analysis 总被引:1,自引:1,他引:0
1. The ratio [ATP]/[ADP][P(i)], as measured by direct determination of the three components in rat liver, was found in various nutritional states to have approximately the same value as the ratio [ATP]/[ADP][P(i)] calculated from the concentrations of lactate, pyruvate, glyceraldehyde phosphate and 3-phosphoglycerate on the assumption that lactate dehydrogenase, glyceraldehyde phosphate dehydrogenase and 3-phosphoglycerate kinase are at near-equilibrium in the liver. This implies that the redox state of the NAD couple in the cytoplasm is linked to, and partially controlled by, the phosphorylation state of the adenine nucleotides. 2. The combined equilibrium constant of the glyceraldehyde 3-phosphate dehydrogenase and 3-phosphoglycerate kinase reactions at 38 degrees C and I0.25, was found to be 5.9x10(-6). 3. The fall of the [NAD(+)]/[NADH] ratio in starvation and other situations is taken to be the consequence of a primary fall of the [ATP]/[ADP][HPO(4) (2-)] ratio. 相似文献
85.
Spleen cells from DBA/2 mice bearing the DBA/2 P815X mastocytoma for approximately 2 weeks can be stimulated in vitro by mastocytoma cells to generate cytotoxicity measured as 51Cr release from mastocytoma cells in a 4-hr assay. These cytotoxic cells will not kill allogeneic cell lines but will kill a series of first transplant generation syngeneic tumors. T cells are involved in that treatment of the responding or the cytotoxic cell populations with either anti-T or anti-theta antibody + complement will abrogate all cytotoxicity. Anti-Ly 2.1 antibody + complement treatment of either responder cells (prior to the in vitro culture with irradiated tumor cells) or effector cells after culture markedly decreases cytotoxicity whereas treatment with anti-Ly 1.1 was more effective prior to culture compared to its effect on cytotoxic cells per se. These T cells are in the small lymphocyte class and occur either singly or in aggregates. Suppression of antisyngeneic tumor cytotoxicity by antibody inhibits preferentially the expression of cytotoxicity in the aggregate fractions. 相似文献
86.
1. The half-life of [15N]urea was found to be significantly longer than that of [14C]urea injected at the same time, the differences being due to endogenous catabolism of urea, which is accompanied by little or no reutilization of 14C but is approx. 20% for 15N. [15N]Urea therefore appears to be valueless as an indicator of nitrogen metabolism unless the extents of endogenous catabolism of urea and of fractional reutilization of 15N can be separately estimated. 2. Though measurements of the radioactivity of expired 14CO2 confirmed the existence of considerable urea catabolism these could not be used for quantitative assessments. 3. Alternative graphical methods based on [14C]urea specific activities in plasma and urine samples were used to calculate the fraction of urea production that is excreted. Values by the two methods were in good agreement and showed that some animals excrete less than half the urea that they produce. 4. Specific activity differences between simultaneous samples of urinary and plasma urea reflect the presence of a pool of urea in the kidney that is not in equilibrium with the body urea pool. Calculations indicate the presence of urea in the kidney that in some cases may represent as much as 15% of the body pool, and in two animals in which post-mortem renal analyses were performed the masses of urea found agreed closely with the calculated values. 5. A model for urea metabolism is proposed that includes this pool in the excretory pathway. The related theory is shown to be adequate to explain the shape of the specific activity curves of urinary urea from the time of injection and the constant delay of the specific activity of urinary urea, relative to that of plasma urea, that is observed after a short preliminary equilibration period. 6. The body urea pool was calculated from the activity retained at 1·5hr. by excluding renal activity and the corrected specific activity of plasma urea at the same time. The urea pool was calculated to be distributed at the plasma concentration in a substantially smaller water volume than that found by injecting tritiated water in five animals. Reasons for this are discussed. 7. Urea synthesis rates calculated from the pool values are in close agreement with rates calculated from the mass of urea recovered in the urine and the fraction of newly synthesized urea that is excreted. 相似文献
87.
A species-non-specific liver plasma-membrane antigen and its involvement in chronic active hepatitis. 总被引:1,自引:0,他引:1 下载免费PDF全文
Rabbit liver plasma membranes were isolated and purified by using an aqueous two-phase polymer system. Examination of these preparations with respect to electron-microscopical appearance, distribution of marker enzymes and gross biochemical composition revealed them to be free from contamination by intracellular components. Sera from ten patients with chronic active hepatitis, four with and six without hepatitis B viral markers (HBsAg) in their sera, produced a single precipitin line on immunodiffusion against a detergent extract of the isolated plasma membranes. Sera from HBsAg-positive and HBsAg-negative patients reacted against the same antigen. This antigen was enriched in the plasma membrane preparations compared with whole-liver homogenates and was identical with a species-non-specific antigen in a macromolecular fraction of normal human liver, which has been previously described as liver-specific lipoprotein. 相似文献
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