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1.
According to data of observations in 2002–2004, differences in the pattern of diurnal fluctuations in the total content and fractional composition of lipids in muscles of mature specimens of kilka Clupeonella cultriventris from the Rybinsk Reservoir in the feeding and spawning periods were revealed. It was established that the feeding intensity in kilka considerably changes throughout 24 h in both periods of the annual cycle, while diurnal fluctuations in the fatness of muscles are distinctly manifested only in the reproductive period and have a dissimilar pattern in specimens of different sexes. In females and males, they are determined mainly by the change in the content of the fraction of reserve lipids-triacylglycerols, as a rule, by its increase in the light hours of the day, several hours after an increase in the feeding activity of fish. The pattern of diurnal fluctuations of the level of lipid fractions (phospholipids, triacylglycerols, cholesterol, and its ethers) in kilka’s muscles differs from that in the feeding period. Possible causes of the change of diurnal variations of the considered indices of lipid metabolism in kilka at an increase in the endocrine activity of its body in the reproductive period is discussed.  相似文献   

2.
在三月红荔枝(Litchi chinensis cv.Sanyuehong)果实膨大期对树冠喷施0.2%磷酸二氢钾(KP)水溶液,以探讨磷酸二氢钾对荔枝果实贮藏性的影响。结果表明:(1) KP处理的果实在贮藏期前17d,失重率及果肉可溶性固形物、酸、VitC、花色素苷等指标的变化趋势与对照基本相似;(2) KP处理的果肉可溶性蛋白质含量变化与对照有明显差异,而果皮的可溶性蛋白质含量在贮藏期前10d变化动态与对照一致,此后呈相反的变化趋势;(3)果皮POD活性显著高于果肉,KP处理和对照的果肉POD活性在贮藏第3d后、果皮POD活性在第17d前分别具有相似变化趋势;(4)果肉中CAT活性在贮藏第3~17d期间都显著或极显著高于果皮,KP处理和对照果肉、果皮CAT活性动态变化均为单峰曲线。  相似文献   

3.
The titre of apple chlorotic leaf spot virus (ACLSV) was higher in microplants of Malus domestica cv. Jonagold than in 2-year-old grafted scions. Cytokinin concentration in the medium increased the titre of prunus necrotic ringspot virus (PNRSV) in the apex of microplants of Prunus insititia cv. Kozlienka but did not affect the titre of ACLSV in M .domestica.Virus titre of ACLSVwas higher in the haulms of autotrophically-grown compared with heterotrophically-grown microplants whereas as for PNRSV the results were the reverse. For both viruses, however, titre of the virus in the roots of autotrophically-grown plants was significantly higher than in haulm tissue from heterotrophic cultures. Ribavirin incorporation resulted in elimination of both viruses. Negative ELISA results were confirmed independently by PCR. The efficacy of Ribavirin in elimination of ACLSV was increased by increasing the concentration of cytokinin in the medium in parallel with decreasing the concentration of Ribavirin. These results are discussed in the context of the reliability of in vitro virus testing.  相似文献   

4.
Thioltransferase (TTase) is a member of the family of thiol-disulfide oxidoreductases that are involved in the maintenance of sulfhydryl homeostasis in cells by catalyzing thiol-disulfide interchange reactions. One of the major consequences of oxidative stress in brain is the formation of protein-glutathione mixed disulfides (through oxidation of protein thiols), which can be reversed by TTase during the recovery of brain from oxidative stress. We therefore examined the presence of TTase in brain regions from rat. In the rat, TTase activity in the whole brain was comparable with the corresponding activity in liver, but significantly higher in hippocampus. The enzyme activity was significantly lower in striatum and cerebellum compared with activity in whole brain. Rat brain TTase shared immunological similarity with the human red blood cell enzyme, but not with the pig liver enzyme. The constitutive expression of the mRNA to TTase was demonstrable by northern blotting. Localization of the TTase mRNA in rat brain by fluorescent in situ hybridization showed the presence of high amounts of mRNA in the olfactory bulb, cortex, and hippocampus and its predominant localization in the neurons. TTase mRNA was also present in Purkinje cells in the cerebellum, in giant reticular neurons in the midbrain, and in the striatal and thalamic neurons. This study demonstrates the constitutive presence of a functional TTase system in brain and delineates the regional and cellular localization of the enzyme in rat brain.  相似文献   

5.
Using the technique of immunohistochemistry in combination with cytophotometry, we have studied the effect of periovulatory hyper- and hypoprolactinemia on the expression of prolactin receptors in various cell types of rat ovaries during early estrus. It has been shown that intense specific staining of oocytes is positively controlled by prolactin. The maximal intensity of specific staining was found in cells of the cumulus and the inner layer of granulosa cells in mature follicles; staining intensity gradually diminished towards the outer boundary cell layer. Postovulatory follicles are distinct from those mature follicles in which there was no ovulation in their more intense manifestation of prolactin receptors in cells of the inner layer and cumulus, as well as in increased positive staining (after prolactin administration) only in the granulosa layer cells closest to theca. In follicles which did not ovulate by the time of the early estrus, prolactin administration leads to a proportional growth of specific immunoreactivity in all cell layers of the granulosa. The administration of bromocryptin, an inhibitor of prolactin secretion, leading to a 10-fold decrease in the prolactin level in the blood, results in a twofold decrease in the intensity of specific staining of all cell layers of the granulosa in either type of follicle. Corpora lutea of the previous cycle have irregularly positioned luteocytes with weak and strong specific staining, the intensity of which is not changed in response to prolactin and diminishes slightly after the administration of bromocryptin. We conclude that the most intense changes in the content of prolactin receptors under the conditions of imbalance of this hormone during the periovulatory period are observed in those follicles where the oocyte did not ovulate by the time of early estrus.  相似文献   

6.
The population dynamics of Moniliformis moniliformis was studied in ‘free-ranging’ laboratory rats, Rattus norvegicus, presented with different relative density levels of M. moniliformis in cockroaches, Periplaneta americana. Changes in selected population parameters of the negative binomial distribution were evaluated as indicators of changes in aggregation. A significant increase in the degree of aggregation of parasites occurred as a result of the increase in relative density of infective stages available to the rats. This increase in aggregation was due to the increase in over-dispersion that occurred in female rats only. The degree of aggregation in females was found to be significantly higher than that in males at both treatment levels. The best indicators of the degree of aggregation were found to be the ratio of the variance to the relative density and the ratio of the log-variance to log-relative density. Changes in k were not correlated with changes in over-dispersion or the relative density.  相似文献   

7.
The effect of alteration of lysine: arginine ratio of the protein on the aortic glycosaminoglycans and glycoproteins was studied in rats fed cholesterol free and atherogenic diet. The concentration of total glycosaminoglycans and of individual fractions was significantly lower in the aorta in the case of diet with lysine: arginine ratio of 1.0, than the diet with a ratio of 2.0. Rats fed globulin fraction isolated from sesame seeds, which has a lysine: arginine ratio of 0.67 also showed significantly lower concentration of total and individual glycosaminoglycan fractions in the aorta than those fed casein (lysine:arginine ratio 2.0). Concentration of total hexose and fucose in the glycoproteins was also lower in the aorta in the case of lysine: arginine ratio 1.0. These results in the light of previous reports of increase in the aortic glycosaminoglycans in the early stages of atherosclerosis and increase in the total hexose and fucose in the glycoproteins in the atherosclerotic aorta indicate that the antiatherogenic effect of a low lysine: arginine ratio in the protein involves alteration in the aortic glycosaminoglycans and glycoproteins.  相似文献   

8.
When white light irradiation inhibits shoot growth in derooted pea ( Pisum sativum L. cv. Alaska) cuttings, it decreases tissue tension, a driving force for shoot growth, by making the cell wall of the inner tissues mechanically rigid. To elucidate the mechanism by which light affects the mechanical properties of the cell wall in the inner tissues, its effect on the chemical properties of the cell walls was studied by analyzing qualitatively and quantitatively cell wall polysaccharides in the epdidermis and inner tissue of pea epicotyls grown in both dark and light. The amount of polysaccharides per subhook in the cell walls of both tissues increased during a 4-h dark incubation. Light suppressed the increase in hemicellulosic (HC)-II and cellulosic polysaccharides in the inner tissues, while it did not affect the increase in other wall fractions in either the epidermal or subepidermal tissues. No light effect was observed on the neutral sugar compositions of pectin, HC-I or HC-II fractions in either of the tissues. Light increased the mass-average molecular mass of xyloglucan and rhamnoarabinogalactan in HC-II fractions in the inner tissues, while such an effect was not observed in the epidermis. These facts suggest that the light-induced decrease in the tissue tension in pea epicotyls is caused by an increase in the molecular size of xyloglucan, rhamnoarabinogalactan in the HC-II fraction and/or the suppression of the synthesis of HC-II and cellulosic polysaccharides in the inner tissues.  相似文献   

9.
We have recently shown that sustained neonatal hyperthyroidism in the rat activates apoptosis of oligodendroglial cells (OLGc) and that inhibition of the proteasome-ubiquitin (Ub) pathway by lactacystin produces increased apoptosis in cerebellar granule cells (CGC). In the present study we have analyzed the relationship between the activation of the Ub-dependent pathway, the expression of the Ub genes and programmed cell death in neurons of the rat cerebellum and cerebral cortex and in OLGc. This study was carried out in normal animals, in rats submitted to sustained neonatal hyperthyroidism and in cell cultures treated with an excess of thyroid hormones. In neurons of the cerebral cortex, thyroid hormone produces an increase of Ub-protein conjugates, an enhancement in the expression of the Ub genes and an increase in apoptosis, while the opposite results are obtained in CGC. These results indicate that in neurons, the changes in the cell death program produced by thyroid hormone run in parallel with those occurring in the Ub-dependent pathway. In OLGc, thyroid hormone increases apoptosis but does not produce changes in the Ub pathway. Preliminary studies indicate that in coincidence with what occurs in optic nerves, the sciatic nerves both in controls and in hyperthyroid animals are unable to form Ub-protein conjugates. These results indicate that in cells of the CNS such as neurons, in which the Ub-dependent pathway is actively expressed, it appears to be closely correlated with apoptosis.  相似文献   

10.
A series of significant changes of the ultrastructure and lipase activity of cotyledon cell were found in peanut (Arachis hypogaea) during pod development. In he initial stage of cotyledon development there were many plastids which kept producing starch grain and there were low lipase activity and very few lipid and protein bodies in the cell. In the middle stage of cotyledon development, a great number of larger lipid bodies were seen in the cell and a lot of protein bodies formed in the vacuoles and continued to increase in size. Lipase activity increased in the cytoplasm, endoplasmic reticulum, protein bodies, plasmalemma and intercellular space. In the later stage of cotyledon development, the lipid bodies did not increase in number but became slightly larger. The protein bodies continued to increase both in number and in size. Lipase acttvity was even hegher in the cytoplasm. In the final stage the protein bodies became irregular in shape and some of them tended to disintegrate with their content entered into the space around the lipid bodies. The lipase activity in the cell declined. The results indicated that the lipid body originated in the cytoplasm and the protein body originated in the vacuole; that the accumulation of oil and protein in peanut cotyledon resulted from the formation and development of lipid and protein bodies in the cell, and that the changes of plasmid and lipase activity in the cell played a role in the development of lipid body during the development of cotyledon.  相似文献   

11.
廖翔华 《动物学报》2007,53(3):470-480
研究了寄生于鲤鱼及草(鲩)鱼的鱊头槽绦虫(Bothriocephalus acheiloghathi)的多样性.作者在1986-2000年收集材料,遍及中国19个省及自治区.在江苏等5省只收集到其它寄生虫的材料,故结果未列入附录1和2.研究结果表明,鲤鱼及草鱼的寄生鱊头槽绦虫的地理分布截然不同.寄生于鲤鱼的鱊头槽绦虫分布于黄河水系的西北地区及黑龙江水系的东北各省及长江上游的四川、云南和贵州,南方各省的鲤鱼不感染这种绦虫.寄生于草鱼的鱊头槽绦虫分布于沿珠江水系的广东、广西及闽江水系的福建,感染池塘的幼龄草鱼,天然水体中未发现感染阳性的草鱼.交义感染试验表明,寄生在这两种鲤科鱼类的头槽绦虫有极强的宿主特异性,草鱼感染的头槽绦虫一年内大部分时间排出发育完全的胚胎卵,而鲤鱼感染的头槽绦虫排出的虫卵多为早期分裂卵,甚至在盛夏,水温在28℃-30℃的情况下也无例外.虫卵发育程度不同,卵的孵化期也有差异.在同等温度28℃-29℃时,草鱼头槽绦虫虫卵的孵化期为1.69±0.17 d;鲤鱼的头槽绦虫虫卵的孵化期为3.98±0.3 d.此外,种群结构也有明显区别,草鱼的头槽绦虫在繁殖季节,体长<1 cm的幼虫占种群的主体,年终时绦虫全部从宿主体内消失,生活周期从初染至消敛约1年;鲤鱼的头槽绦虫主体全年皆为孕节成虫,在Ⅱ龄商品鱼中继续繁殖.本研究表明,鲤鱼及草鱼的寄生鱊头槽绦虫显示的多样性是因长期适应不同生活环境从而演化为两个不同的亚种[动物学报 53(3):470-480,2007].  相似文献   

12.
Carbon Quality and Stocks in Organic Horizons in Boreal Forest Soils   总被引:1,自引:0,他引:1  
We investigated the mechanisms that determine the quality and quantity of organic carbon (C) stocks in boreal forest soils by analyzing both qualitative and quantitative changes in the organic fractions in the soil organic matter (OM) in a vertical gradient in the decomposition continuum of the organic horizon [litter layer (L), fermentation layer (F), and humus layer (H)] in forest soils using a sequential fractionation method at two forest types along a climatic gradient in Finland. We predicted that the concentrations of water-soluble (WSE) and non-polar (NPE) extractives should decrease and those of the acid-soluble (AS) fraction and acid-insoluble residue (AIR) should increase from the L to the F, and from the F to the H layers, but the C/N ratio of soil OM should stay constant after reaching the critical quotient. We also predicted that the AIR concentrations should be higher in the south than north boreal, and in sub-xeric than mesic forests. Consistent with our hypothesis, the concentrations of WSE and NPE fractions decreased and concentrations of AIR increased in the vertical soil gradient. The highest concentrations of the AS fraction were found in the F layer. The C/N ratio was lowest in the F layer, and the highest in the H layer, indicating that soil OM is depleted in N in relation to C along the vertical soil gradient. Concentrations of WSE and NPE were lower, and concentrations of AIR were higher in the south than in north boreal forests, which is in agreement with our hypothesis that higher soil temperatures may enhance accumulation of slowly decomposable OM in the soil. The concentrations of AIR were higher in the sub-xeric than mesic forests. Contrary to our expectations, however, the differences in the chemical quality in soil OM between the site types were amplified from the L to the H layer. The size of the C storage was significantly larger in south than north boreal sites, and larger in the mesic than in the sub-xeric sites.  相似文献   

13.
Ghrelin was originally purified and characterized in rats and humans as the first identified endogenous ligand of the growth hormone secretagogue receptor. In mammals, ghrelin is mainly produced in the stomach, with minor levels of ghrelin present in the brain and various other tissues. Ghrelin is involved in the regulation of many physiological functions including the regulation of growth hormone secretion and food intake in mammals. The gene and peptide structures of ghrelin have been recently identified in several fish species. As in mammals, ghrelin mRNA is mainly expressed in the gut of fish. Ghrelin is involved in the regulation of a number of physiological functions, including the regulation of pituitary hormone release and the stimulation of food intake in fish. In this review, we wish to provide an up-to-date discussion on the structure, distribution and functions of ghrelin in fish, in comparison to ghrelin in other vertebrates.  相似文献   

14.
Vigna radiata (L.) seedlings (5-d-old) were exposed to different concentrations of NaCl in light and in dark. The content of proline in the shoots increased with an increase in NaCl concentration, in light as well as in dark. But, irrespective of the concentration of NaCl, proline accumulation in the shoots was higher in light than in dark. Pretreatment of seedlings with dichlorophenyl dimethyl urea (DCMU) did not make any significant difference in light promoted stress induced proline accumulation. As DCMU is a potent inhibitor of photosynthetic electron transport, the light reaction of photosynthesis was not responsible for the observed light promotion of stress induced proline accumulation. In another set of experiments, 5-d-old green as well as etiolated seedlings were exposed to NaCl stress in the presence of different concentrations of sucrose. Irrespective of the concentration of sucrose used, proline content in shoots of stressed seedlings was higher in light than in dark. Although, sucrose enhanced NaCl stress induced increase in proline content in dark by about 32 %, this enhancement was not comparable to the 286 % increase in proline content brought about by light. These results showed that certain factors other than photosynthesis play a role in light promotion of stress induced proline accumulation.  相似文献   

15.
It is noteworthy that exposure to opiates during fetal development results in permanent changes in adults related to morphological, behavioral and biochemical measures; however little is known concerning the effects of such drugs in early postnatal life. We investigated in newborn rats the effects of prenatal morphine-exposure on both—the hypothalamic metabolism of norepinephrine (NE), serotonin (5 HT) and neuropeptide Y (NPY)—the activity of the hypothalamo-pituitary gonadal and adrenal axes. In a previous study performed in newborns of untreated mothers, we reported some sex-dependent changes in the metabolism of NE, 5 HT and NPY in the hypothalamus and an early activation of the gonadostimulating function and of the corticostimulating one. In control newborns from saline-treated mothers, a slight increase in the hypothalamic metabolism of NE (males) and 5 HT (males and females) was observed and it was comparable in both sexes. On the other hand, the hypothalamic content of NPY was unaffected in early postnatal period in newborn males as well as in females. These changes observed on hypothalamic metabolisms are temporally correlated with the early postnatal activation of the corticostimulating function in neonates of both sexes and that of the gonadostimulating one, mainly in males. Prenatal morphine exposure altered the hypothalamic metabolism of 5 HT which was increased mainly in newborn females but did not affect either the metabolism of NE or the NPY content of the hypothalamus. The more drastic effect of the prenatal morphine treatment is the atrophy and hypoactivity of the adrenals in newborns of both sexes at birth time and during the early postnatal period. In contrast morphine did not impair postnatal surge of the plasma testosterone level in male pups as well as late and slight increase of plasma estradiol in female ones.  相似文献   

16.
The anatomical distribution and seasonal variations in aromatase activity and in the number of aromatase-immunoreactive cells were studied in the brain of free-living male pied flycatchers (Ficedula hypoleuca). A high aromatase activity was detected in the telencephalon and diencephalon but low to negligible levels were present in the optic lobes, cerebellum, and brain stem. In the diencephalon, most aromatase-immunoreactive cells were confined to three nuclei implicated in the control of reproductive behaviors: the medial preoptic nucleus, the nucleus of the stria terminalis, and the ventromedial nucleus of the hypothalamus. In the telencephalon, the immunopositive cells were clustered in the medial part of the neostriatum and in the hippocampus as previously described in another songbird species, the zebra finch. No immunoreactive cells could be observed in the song control nuclei. A marked drop in aromatase activity was detected in the anterior and posterior diencephalon in the early summer when the behavior of the birds had switched from defending a territory to helping the female in feeding the nestlings. This enzymatic change is presumably controlled by the drop in plasma testosterone levels observed at that stage of the reproductive cycle. No change in enzyme activity, however, was seen at that time in other brain areas. The number of aromatase-immunoreactive cells also decreased at that time in the caudal part of the medial preoptic nucleus but not in the ventromedial nucleus of the hypothalamus (an increase was even observed), suggesting that differential mechanisms control the enzyme concentration and enzyme activity in the hypothalamus. Taken together, these data suggest that changes in diencephalic aromatase activity contribute to the control of seasonal variations in reproductive behavior of male pied flycatchers but the role of the telencephalic aromatase in the control of behavior remains unclear at present.  相似文献   

17.
We investigated the effects of chronic stress combined with high sucrose intake on the morphology of the adrenal glands in young rats. Male Wistar rats were fed a standard chow diet and allocated into control (C; tap water), chronic restraint stress (St), 30% sucrose diet (S30) and 30% sucrose diet + chronic restraint stress (S30 + St) groups. St consisted of 1 h daily sessions, 5 days/week for 4 weeks. Chronic stress reduced the thickness of the zona glomerulosa (ZG) and zona fasciculata (ZF) in both right and left glands; the thickness of the zona reticularis (ZR) was increased in the right gland. Cell density was greater in the ZF and medulla of both right and left glands, whereas cell density increased in the ZR of only the left gland. The percentage of small cells was lower in the ZG, whereas more large cells were found in the left gland. A similar result was obtained for the ZF, ZR and medulla in both right and left glands. Chronic stress increased the area covered by blood vessels in the ZR of the right gland, but decreased the area in the ZR of the left gland. The area covered by blood vessels was reduced in the medulla of both right and left glands in rats subjected to chronic stress. Infiltration of immune cells was increased by chronic stress in all layers of the cortex of the left gland, but was reduced in the medulla of the right gland. A high sucrose diet reduced the thickness of the medulla in the left gland. Cell proliferation increased in the ZG of the right gland and the weight of the right adrenal gland increased. Reduced cell proliferation in the ZG of the left gland was associated with a reduction in the area covered by blood vessels. In addition, the area covered by blood vessels decreased in the medulla of both glands. Our findings demonstrate that exposure to chronic stress during early life causes morphometric changes in adrenal glands.  相似文献   

18.
Summary An analysis of the allometric relations of the total volumes occupied by prolactin (PRL) and corticotropic (ACTH) cells (PRL volume and ACTH volume, respectively) to body length and a study of the immunocytochemical staining intensity of PRL and ACTH cells were used to determine the differences in activity of PRL and ACTH cells in freshwater-reared and in saltwater-reared Cynolebias whitei during the entire lifespan of this annual cyprinodont fish. An inflection in the allometric relation of PRL volume to body length was observed in fish of one-week old. The relatively large PRL volume in younger fish may be related to PRL cell activity before hatching. No inflections were observed in the allometric relations of PRL volume and ACTH volume to body length at the onset of maturation and the onset of ageing, indicating that the increased pituitary growth in maturing and ageing C. whitei is not the result of changes in PRL or ACTH cells. The slope of the allometric relation of PRL volume to body length in freshwater-reared fish was significantly steeper than the slope in saltwater-reared fish. The PRL volume in adult freshwater-reared fish was eight times larger than that in saltwater-reared fish of the same length. The intensity of immunocytochemical staining of saltwater PRL cells was significantly reduced. These volumetric and staining differences correspond to the low functional demand put upon PRL cells in saltwater-adapted fish. In contrast, the slope of the allometric relation of ACTH volume to body length and the intensity of immunocytochemical staining of ACTH cells were similar in freshwater-reared and in saltwater-reared fish. It is concluded that the functional demand put upon ACTH cells is similar in freshwater-reared and saltwater-reared C. whitei; the involvement of ACTH cells in the osmoregulation of the fish in both environments is similar.  相似文献   

19.
20.
Time-course of ABA, cytokinins, monosaccharides (MS), and water-soluble polysaccharides (WSP) contents were followed during cold dormancy period in the bulbs of tulip (Tulipa bifloriformis Vved.) that stayed over winter in the open ground or were cold-forced into bloom in a greenhouse. In both cases, the level of monosaccharides and water-soluble polysaccharides in the storage scale tissues increased, whereas the MS/WSP ratio in the bulbs planted in the open remained essentially the same and in case of forcing treatment decreased almost fivefold. In the apical bud tissues, the level of monosaccharides also rose in both cases, but the MS/WSP ratio in the open was greater throughout the whole experiment. The level of cytokinins in the apical bud tissues in the open was higher than in the forcing case, although the changes in their total content were identical following both treatments. Following the forcing treatment, the contents of free and bound ABA in the apical bud tissues increased reaching their peaks by the end of cold period. In the open, there were two peaks of free ABA: in October (when early frosts occurred) and in March (at the end of the wintering period). The winter forcing treatment resulted in rapid depletion of energy and plastic resources in T. bifloriformis and the death of 20% of embryonic flower buds (in the open, all flower buds survived). Nevertheless, plant adaptation potential ensured the development of generative shoots with 4–5 normal flowers, which makes it possible to use this species of multiflorous tulip for winter forcing in a greenhouse.  相似文献   

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