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101.
Oxygen consumption and ammonia excretion rates were assessed for Terebratulina retusa (L.) held under 3 different regimes of temperature and food availability. These were: 5.6?C, no food (cold, starved); 5.8?C, food present (cold, fed) and 10.7?C food present (warm, fed), which simulated winter conditions, summer conditions and an intermediate treatment. Regressions of oxygen consumption on ash‐free dry weight (AFDW) had slopes which were not significantly different from each other and ranged from 0.953 to 0.999. A common slope of 0.976 was calculated and intercepts based on the common slope used to compare oxygen consumption in each treatment. The rise from cold, starved conditions to warm, fed was 24.5 per cent and this was significant (P < 0.05). Other differences were not significant (P > 0.05) but the cold, fed result was 12.6 per cent higher than cold, starved. Therefore feeding and temperature probably account for equivalent proportions of the rise in metabolism from winter to summer. Ammonia production data were much more variable. Excretion rates of a 50 mg AFDW individual (in ng‐at NH3‐N.h‐1) were as follows: cold, starved: 30.2 cold, fed: 7.1; and warm, fed: 22.9. Oxygen to nitrogen (O:N) ratios reflected these results. Mean O:N ratios were: cold, starved: 8.0; cold, fed: 42.4; warm, fed: 16.3. This shows that the simulated winter group relied heavily on protein to fuel their metabolism, the simulated summer group were less dependent on protein and the intermediate group probably used lipids and carbohydrates to fuel metabolic demands. This possibly reflected a trade off between food supply and increased metabolism from treatment to treatment, demonstrating a flexibility which could have been a contributing factor in the ecological tolerance and geological longevity of some brachiopods.  相似文献   
102.
Flooding impacts ground nesting ant colonies by destroying the infrastructure housing and organizing societal function. Here, we report the convergent evolution in distantly related ant species of a behavioral trait that minimizes costs of flooding: the construction of earthen levees around nest entrances. In a South American floodplain ecosystem, we observed five ant species constructing prominent earthen berms encircling nest entrances shortly after large rainfall events. In four of these species, experimental flooding of nests demonstrated that earthen berms sufficed to prevent floodwaters from entering the below ground portions of the nest. Additional manipulations revealed that levee breaching caused, pronounced, and extended reductions in food collection for two distantly related species. Foraging was preempted by the allocation of workers to repair the internal structure of the nest. These findings represent convergent evolution of a functionally important nest construction behavior in response to comparable selective forces.  相似文献   
103.
Discovery of a new class of DFG-out p38α kinase inhibitors with no hinge interaction is described. A computationally assisted, virtual fragment-based drug design (vFBDD) platform was utilized to identify novel non-aromatic fragments which make productive hydrogen bond interactions with Arg 70 on the αC-helix. Molecules incorporating these fragments were found to be potent inhibitors of p38 kinase. X-ray co-crystal structures confirmed the predicted binding modes. A lead compound was identified as a potent (p38α IC(50)=22 nM) and highly selective (≥ 150-fold against 150 kinase panel) DFG-out p38 kinase inhibitor.  相似文献   
104.
Choi BK  Kim YH  Choi JH  Kim CH  Kim KS  Sung YC  Lee YM  Moffett JR  Kwon BS 《Cytokine》2011,55(3):420-428
4-1BB (CD137) is a powerful T-cell costimulatory molecule in the treatment of virus infections and tumors, but recent studies have also uncovered regulatory functions of 4-1BB signaling. Since 4-1BB triggering suppresses autoimmunity by accumulating indoleamine 2,3-dioxygenase (IDO) in dendritic cells (DCs) in an interferon (IFN)-γ-dependent manner, we asked whether similar molecular and cellular changes were induced by 4-1BB triggering in virus-infected mice. 4-1BB triggering increased IFN-γ and IDO, and suppressed CD4(+) T cells, in C57BL/6 mice infected with the type 1 KOS strain of Herpes simplex virus (HSV-1), as it does in an autoimmune disease model. Detailed analysis of the CD4(+) T suppression showed that freshly activated CD62L(high) T cells underwent apoptosis in the early phase of suppression, and CD62L(low) effector/memory T cells in the later phase. Although 4-1BB triggering resulted in similar cellular changes - increased CD8(+) T and decreased CD4(+) T cells, it had different effects on mortality in mice infected with HSV-1 RE, influenza, and Japanese encephalitis virus (JEV); it increased mortality in influenza-infected mice but decreased it in JEV-infected mice. Since the dominant type of immune cell generated to protect the host was different for each virus - CD4(+) T cells and neutrophils in HSV-1 RE infection, both CD4(+) T and CD8(+) T cells in influenza infection, and a crucial role for B cells in JEV infection, 4-1BB triggering resulted in different therapeutic outcomes. We conclude that the therapeutic outcome of 4-1BB triggering is determined by whether the protective immunity generated against the virus was beneficially altered by the 4-1BB triggering.  相似文献   
105.
The midgut of larval mosquitoes (Aedes aegypti) mediates a cycle of alkali secretion in the anterior segment (AMG) followed by partial reacidification in the posterior segment (PMG); both processes are serotonin-dependent. Here we report that intracellular Ca(2+)(Ca(i)(2+)) as indicated by Fura-2 fluorescence, is elevated in both tissues in response to serotonin, but the time courses differ characteristically in the two gut segments, and Ca(2+)-free solution abolishes the serotonin response in AMG, but not in PMG, whereas Thapsigargin, an inhibitor of endoplasmic Ca(2+) transport, abolished responsiveness to 5-HT in PMG. These results suggest the origins for the Ca(2+) signal differ between the two tissues. Quantitative real-time RT-PCR revealed expression of 5 putative 5-HT receptor types in AMG, including 5-HT(2)-like receptors which would be expected to initiate a Ca(2+) signal. None of these receptors were highly expressed in PMG. Cyclic AMP (cAMP) is a secretagogue for both tissues, but H89, an inhibitor of Protein Kinase A (PKA), is also a secretagogue, suggesting that the stimulatory effect of cAMP involves a non-PKA pathway. Cytochalasins B and D block the effect of 5-HT in AMG, suggesting a vesicle-fusion mechanism of activation of the basal V-ATPase in this tissue. Finally, in PMG, elevation of luminal pH increases (Ca(i)(2+)) and decreases intracellular pH as measured by BCECF fluorescence. These responses suggest that the rate of acid secretion by PMG might be responsive to local demand for luminal reacidification as well as to serosal serotonin.  相似文献   
106.
In Colombia, like most Neotropical countries, faunistic studies on flower flies have been occasional and most of them have been primarily focused on taxonomy. Colombia is the second-most species-rich country in flower fly diversity in the Neotropics after Brazil, and has one of the highest numbers of species per unit area (2.49 per 10,000?km2), based on a review of literature and national collections. Including new data presented here, a total of 47 genera and 300 species are recorded in Colombia. The genera Scaeva Fabricius and Lycastrirhyncha Bigot, as well as 101 species are recorded here for the first time. The altitudinal range and the distribution of the flower fly genera in Colombia are presented. A preliminary comparison of the fauna of Colombia with that of other Neotropical countries is given. A historical perspective is also provided in order to illustrate how Colombian Syrphidae knowledge has progressed over the last 168?years. Information presented here will be useful for ongoing and future biodiversity research as well as conservation projects on Syrphidae in the Neotropical region.  相似文献   
107.
ABSTRACT: BACKGROUND: Metabotropic glutamate receptors (mGluRs) have been identified as significant analgesic targets. Systemic treatments with inhibitors of the enzymes that inactivate the peptide transmitter N-acetylaspartylglutamate (NAAG), an mGluR3 agonist, have an analgesia-like effect in rat models of inflammatory and neuropathic pain. The goal of this study was to begin defining locations within the central pain pathway at which NAAG activation of its receptor mediates this effect. RESULTS: NAAG immunoreactivity was found in neurons in two brain regions that mediate nociceptive processing, the periaqueductal gray (PAG) and the rostral ventromedial medulla (RVM). Microinjection of the NAAG peptidase inhibitor ZJ43 into the PAG contralateral, but not ipsilateral, to the formalin injected footpad reduced the rapid and slow phases of the nociceptive response in a dose-dependent manner. ZJ43 injected into the RVM also reduced the rapid and slow phase of the response. The group II mGluR antagonist LY341495 blocked these effects of ZJ43 on the PAG and RVM. NAAG peptidase inhibition in the PAG and RVM did not affect the thermal withdrawal response in the hot plate test. Footpad inflammation also induced a significant increase in glutamate release in the PAG. Systemic injection of ZJ43 increased NAAG levels in the PAG and RVM and blocked the inflammation-induced increase in glutamate release in the PAG. CONCLUSION: These data demonstrate a behavioral and neurochemical role for NAAG in the PAG and RVM in regulating the spinal motor response to inflammation and that NAAG peptidase inhibition has potential as an approach to treating inflammatory pain via either the ascending (PAG) and/or the descending pain pathways (PAG and RVM) that warrants further study.  相似文献   
108.
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110.
Temporal genetic variation in River Bush Atlantic salmon was low and much less than among geographically discrete samples reported from elsewhere.  相似文献   
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