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121.
Successful behavioral-based control methods rely on the accurate knowledge of the mating dynamics of the target insect. Age at first mating affects reproductive potential and the chance of multiple mating. The cabbage moth, Copitarsia decolora (Guenée) is an important pest of a number of commodities. We investigated combinations of age, body size and mating history to determine how these variables affect insect reproductive capacity. Fecundity and fertility decreased as the age of mating pairs increased, heavy and average sized females laid more eggs than light females. Female multiple mating did not enhance fecundity nor fertility potential. Furthermore, spermatophore size did not determine female re-mating behavior. However, female fecundity and fertility was related to the male mating history. Our results show that SIT is a valuable tool for controlling this pest.  相似文献   
122.
The interaction at neutral pH between wild-type and a variant form (R3A) of the amyloid fibril-forming protein β2-microglobulin (β2m) and the molecular chaperone αB-crystallin was investigated by thioflavin T fluorescence, NMR spectroscopy, and mass spectrometry. Fibril formation of R3Aβ2m was potently prevented by αB-crystallin. αB-crystallin also prevented the unfolding and nonfibrillar aggregation of R3Aβ2m. From analysis of the NMR spectra collected at various R3Aβ2m to αB-crystallin molar subunit ratios, it is concluded that the structured β-sheet core and the apical loops of R3Aβ2m interact in a nonspecific manner with the αB-crystallin. Complementary information was derived from NMR diffusion coefficient measurements of wild-type β2m at a 100-fold concentration excess with respect to αB-crystallin. Mass spectrometry acquired in the native state showed that the onset of wild-type β2m oligomerization was effectively reduced by αB-crystallin. Furthermore, and most importantly, αB-crystallin reversibly dissociated β2m oligomers formed spontaneously in aged samples. These results, coupled with our previous studies, highlight the potent effectiveness of αB-crystallin in preventing β2m aggregation at the various stages of its aggregation pathway. Our findings are highly relevant to the emerging view that molecular chaperone action is intimately involved in the prevention of in vivo amyloid fibril formation.  相似文献   
123.
Propofol (2,6-diisopropylphenol), some substituted phenols (2,6-dimethylphenol and 2,6-ditertbutylphenol) and their 4-nitrosoderivatives have been compared for their scavenging ability towards 1,1-diphenyl-2-picrylhydrazyl and for their inhibitory action on lipid peroxidation. These products were also compared to the classical antioxidants butylated hydroxytoluene and butylated hydroxyanisole. When measuring the reactivity of the various phenolic derivatives with 1,1-diphenyl-2-picrylhydrazyl the following order of effectiveness was observed: butylated hydroxyanisole>propofol>2,6-dimethylphenol>2,6-di-tertbutylphenol?>?butylated hydroxytoluene. In cumene hydroperoxide-dependent microsomal lipid peroxidation, propofol acts as the most effective antioxidant, while butylated hydroxyanisole, 2,6-di-tertbutylphenol and butylated hydroxytoluene exhibit a rather similar effect, although lower than propofol. In the iron/ascorbate-dependent lipid peroxidation propofol, at concentrations higher than 10?μM, exhibits antioxidant properties comparable to those of butylated hydroxytoluene and butylated hydroxyanisole. 2,6-Dimethylphenol is scarcely effective in both lipoperoxidative systems. The antioxidant properties of the various molecules depend on their hydrophobic characteristics and on the steric and electronic effects of their substituents. However, the introduction of the nitroso group in the 4-position almost completely removes the antioxidant properties of the examined compounds. The nitrosation of the aromatic ring of antioxidant molecules and the consequent loss of antioxidant capacity can be considered a condition potentially occurring in vivo since nitric oxide and its derivatives are continuously formed in biological systems.  相似文献   
124.
R. Federico  R. Angelini 《Planta》1988,173(3):317-321
Diamine-oxidase (DAO; EC 1.4.3.6) activity and di-and polyamine levels were estimated along the epicotyl and root of light-grown and etiolated lentil (Lens culinaris Medicus) and pea (Pisum sativum L.) seedlings. The activity of DAO was higher in etiolated epicotyls than in lightgrown ones. In both species there was a positive correlation between DAO activity and the diamine (putrescine and cadaverine) levels along the whole epicotyl and root. Polyamine (spermine and spermidine) distribution seemed to be associated with the meristematic and elongating zone of the epicotyl and root. The physiological function of DAO is discussed in relation to its possible role in providing hydrogen peroxide to peroxidase-dependent reactions occurring in the cell wall.Abbreviations CAD cadaverine - DA diamine - DAO diamine oxidase - PA polyamine - PUT putrescine - SPD spermidine - SPM spermine  相似文献   
125.
Heart failure with preserved ejection fraction (HFpEF) is the most common type of HF in older adults. Although no pharmacological therapy has yet improved survival in HFpEF, exercise training (ExT) has emerged as the most effective intervention to improving functional outcomes in this age‐related disease. The molecular mechanisms by which ExT induces its beneficial effects in HFpEF, however, remain largely unknown. Given the strong association between aging and HFpEF, we hypothesized that ExT might reverse cardiac aging phenotypes that contribute to HFpEF pathophysiology and additionally provide a platform for novel mechanistic and therapeutic discovery. Here, we show that aged (24–30 months) C57BL/6 male mice recapitulate many of the hallmark features of HFpEF, including preserved left ventricular ejection fraction, subclinical systolic dysfunction, diastolic dysfunction, impaired cardiac reserves, exercise intolerance, and pathologic cardiac hypertrophy. Similar to older humans, ExT in old mice improved exercise capacity, diastolic function, and contractile reserves, while reducing pulmonary congestion. Interestingly, RNAseq of explanted hearts showed that ExT did not significantly modulate biological pathways targeted by conventional HF medications. However, it reversed multiple age‐related pathways, including the global downregulation of cell cycle pathways seen in aged hearts, which was associated with increased capillary density, but no effects on cardiac mass or fibrosis. Taken together, these data demonstrate that the aged C57BL/6 male mouse is a valuable model for studying the role of aging biology in HFpEF pathophysiology, and provide a molecular framework for how ExT potentially reverses cardiac aging phenotypes in HFpEF.  相似文献   
126.
127.
Litterfall dynamics (production, seasonality and nutrient composition) are key factors influencing nutrient cycling. Leaf litter characteristics are modified by species composition, site conditions and water availability. However, significant evidence on how large‐scale, global circulation patterns affect ecophysiological processes at tree and ecosystem level remains scarce due to the difficulty in separating the combined influence of different factors on local climate and tree phenology. To fill this gap, we studied links between leaf litter dynamics with climate and other forest processes, such as tree‐ring width (TRW) and intrinsic water‐use efficiency (iWUE) in two mixtures of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) in the south‐western Pyrenees. Temporal series (18 years) of litterfall production and elemental chemical composition were decomposed following the ensemble empirical mode decomposition method and relationships with local climate, large‐scale climatic indices, TRW and Scots pine's iWUE were assessed. Temporal trends in N:P ratios indicated increasing P limitation of soil microbes, thus affecting nutrient availability, as the ecological succession from a pine‐dominated to a beech‐dominated forest took place. A significant influence of large‐scale patterns on tree‐level ecophysiology was explained through the impact of the North Atlantic Oscillation (NAO) and El Niño–Southern Oscillation (ENSO) on water availability. Positive NAO and negative ENSO were related to dry conditions and, consequently, to early needle shedding and increased N:P ratio of both species. Autumn storm activity appears to be related to premature leaf abscission of European beech. Significant cascading effects from large‐scale patterns on local weather influenced pine TRW and iWUE. These variables also responded to leaf stoichiometry fallen 3 years prior to tree‐ring formation. Our results provide evidence of the cascading effect that variability in global climate circulation patterns can have on ecophysiological processes and stand dynamics in mixed forests.  相似文献   
128.
The reintroduction of dengue virus type 3 (DENV-3) in Brazil in 2000 and its subsequent spread throughout the country was associated with genotype III viruses, the only DENV-3 genotype isolated in Brazil prior to 2002. We report here the co-circulation of two different DENV-3 genotypes in patients living in the Northern region of Brazil during the 2002-2004 epidemics. Complete genomic sequences of viral RNA were determined from these epidemics, and viruses belonging to genotypes V (Southeast Asia/South Pacific) and III were identified. This recent co-circulation of different DENV-3 genotypes in South America may have implications for pathological and epidemiological dynamics.  相似文献   
129.
Animal experiments and observations in human brains have convincingly shown that sexual differentiation not only concerns the genitalia but also the brain. This has been investigated also in the light of a possible explanation of a presumed biological aetiology of transsexuality. The volume of the central subdivision of the bed nucleus of the stria terminalis, a brain area that is essential for sexual behaviour, has been reported to be larger in men than in women. Additionally, the number of somatostatin expressing neurons in this region was shown to be higher in men than in women. As neuronal production of somatostatin is involved the idea is striking whether somatostatin-receptor density in the cortex of cerebral hemispheres might be related to gender identity. We investigated in vivo the density of somatostatin-receptors in selected regions of the human brain in both sexes by means of receptor scintigraphy. Basal ganglia tracer uptake of 111-In-Pentreotide was equally low in both genders at 0,80% +/ 0,26 (related to tracer uptake of the whole brain layer). Temporal cortex accumulated at 2,9% +/ 1,1 in men and at 2,3% +/ 0,76 in women. Frontal brain region had an uptake of 3,0% +/ 1,4 in male and of 2,5% +/ 1,3 in female. This shows a tendency in males for relatively augmented uptake indicating higher somatostatin receptor density in temporal and frontal cerebral cortex.  相似文献   
130.
In the plasma membrane of the green alga Monoraphidium braunii there are at least two monovalent anion transport systems. One of them is specific for bicarbonate. This transport system is activated by blue light and its induction is triggered by a decrease in the external CO2 concentration. The second transport system is responsible for nitrate uptake at least. This transport system is also activated by blue light and its induction occurs when there is no ammonium in the external medium. Both transport systems are synthesized independently. Hence, when M. braunii cells grow with nitrate as the only nitrogen source under high CO2, they have a nitrate transport system but lack a bicarbonate transporter. Conversely, cells grown with ammonium under low CO2, have a bicarbonate transport system but lack a nitrate transporter. Both transport systems are induced in cells irradiated with white light in the absence of a carbon source, suggesting that there may be precursors in the plasma membrane that only need the synthesis and assembly of some component(s) to become fully active. The induction of nitrate and nitrite reductases, however, only takes place when a carbon source is supplied to the cells.  相似文献   
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