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31.
对氧碱漂白过程中木质素氧化进行定量分析,分析方法是基于氧化前后高锰酸钾消耗量的变化。该方法对溶出残余木质素的氧化结果分析发现其呈明显3个阶段：第一段木质素氧化的当量电荷数约4～5／木质素单元;木质素总氧化电荷数大约为9／木质素单元。这些数据以及甲氧基的脱除（75％）均表明：木质素的氧化不仅发生在酚型木质素单元,同时也发生在非酚型结构单元上。只有第一阶段氧化反应是木质素与氧气直接反应,而在第二、三阶段主要是协同氧化作用,氧化反应过程中产生的活性氧基团扮演了一定角色。通过对低浓度针叶材硫酸盐浆的氧漂研究发现：当卡伯值下降一半（25．4至13．4）时平均每个木质素单元氧化3当量电子,氧漂后的纸浆中仍然有大量未被氧化的残余木质素。定量地证明了在氧漂过程中木质素氧化是脱木质素反应的实质。  相似文献   
32.
Neonicotinoid pesticides (NNs) cause behavioral abnormalities in mammals, raising concerns about their effects on neural circuit activity. We herein examined the neurological effects of the NN clothianidin (CLO) by in vivo Ca2+ imaging using two-photon microscopy. Mice were fed the no-observed-adverse-effect-level (NOAEL) dose of CLO for 2 weeks and their neuronal activity in the primary somatosensory cortex (S1) was observed weekly for 2 weeks. CLO exposure caused a sustained influx of Ca2+ in neurons in the S1 2/3 layers, indicating hyperactivation of neurons. In addition, microarray gene expression analysis suggested the induction of neuroinflammation and changes in synaptic activity. These results demonstrate that exposure to the NOAEL dose of CLO can overactivate neurons and disrupt neuronal homeostasis.  相似文献   
33.
The objectives of this study were to assess and compare the environmental impacts of two types of dairy farming systems, one of which makes use of whole‐crop rice silage and the other of which is conventional, using life cycle assessment (LCA). The functional unit was defined as 1 kg of 4% fat‐corrected milk (FCM). The processes associated with the dairy farming life cycle, such as feed production, feed transport, animal management including biological activity of the animal, and waste treatment were included within the system's boundaries. Environmental impacts of the rice silage‐using and conventional dairy farming systems were 987 and 972 g CO2 equivalents for global warming, 6.87 and 7.13 g SO2 equivalents for acidification, 1.19 and 1.23 g PO4 equivalents for eutrophication, and 5.53 and 5.81 MJ for energy consumption, respectively. Our results suggest that the dairy farming system using rice silage in Japan has smaller environmental impacts for acidification, eutrophication, and energy consumption, and a larger impact for global warming compared with conventional farming. Further interpretation integrating these impact categories suggested 1.1% lower environmental impact of the rice silage‐using dairy farming system as a whole.  相似文献   
34.
A portion of the minute chylomicrons less than 75 nm in diameter are transcytosed from the extravascular tissue into the subepithelial blood capillaries (sBC) in the villous apices of the rat jejunum. However, the details of the transportation mechanism have not been clarified. In this study, the endothelial receptor involved in the transportation of minute chylomicrons into the sBC’s lumina was immunohistochemically and histoplanimetrically examined in intestinal villi of the rat jejunum. Immunopositivity for very low density lipoprotein (VLDL) receptor was detected on the luminal and basal surfaces of the endothelial cells of sBC in approximately 68% of those apices of jejunal villi that possessed numerous chylomicrons in the lamina propria, while VLDL receptor was detected on the endothelial cells of sBC in only approximately 8% of intestinal villi that possessed few or no chylomicrons in the lamina propria. No immunopositivity for LDL receptor was detected in the sBC of all intestinal villi. These findings suggest that VLDL receptor is expressed by the endothelial cells of the sBC in conjunction with the filling of the lamina propria of jejunal villi with many chylomicrons produced by the villous columnar epithelial cells and that the VLDL receptor mediates the transportation of minute chylomicrons, maybe VLDL, into the subepithelial portal blood from the extravascular tissue of the rat jejunal villi.  相似文献   
35.
Neonicotinoids, some of the most widely used pesticides in the world, act as agonists to the nicotinic acetylcholine receptors (nAChRs) of insects, resulting in death from abnormal excitability. Neonicotinoids unexpectedly became a major topic as a compelling cause of honeybee colony collapse disorder, which is damaging crop production that requires pollination worldwide. Mammal nAChRs appear to have a certain affinity for neonicotinoids with lower levels than those of insects; there is thus rising concern about unpredictable adverse effects of neonicotinoids on vertebrates. We hypothesized that the effects of neonicotinoids would be enhanced under a chronic stressed condition, which is known to alter the expression of targets of neonicotinoids, i.e., neuronal nAChRs. We performed immunohistochemical and behavioral analyses in male mice actively administered a neonicotinoid, clothianidin (CTD; 0, 10, 50 and 250 mg/kg/day), for 4 weeks under an unpredictable chronic stress procedure. Vacuolated seminiferous epithelia and a decrease in the immunoreactivity of the antioxidant enzyme glutathione peroxidase 4 were observed in the testes of the CTD+stress mice. In an open field test, although the locomotor activities were not affected, the anxiety-like behaviors of the mice were elevated by both CTD and stress. The present study demonstrates that the behavioral and reproductive effects of CTD become more serious in combination with environmental stress, which may reflect our actual situation of multiple exposure.  相似文献   
36.
Mammalian sexual fate is determined by the presence or absence of sex determining region of the Y chromosome (Sry) in the “bipotential” gonads. Recent studies have demonstrated that both male and female sexual development are induced by distinct and active genetic pathways. Breeding the Y chromosome from Mus m. domesticus poschiavinus (POS) strains into C57BL/6J (B6J) mice (B6J-XYPOS) has been shown to induce sex reversal (75%: bilateral ovary, 25%: true hermaphrodites). However, our B6N-XYPOS mice, which were generated by backcrossing of B6J-XYPOS on an inbred B6N-XX, develop as males (36%: bilateral testis with fertility as well as bilateral ovary (34%), and the remainder develop as true hermaphrodites. Here, we investigated in detail the expressions of essential sex-related genes and histological features in B6N-XYPOS mice from the fetal period to adulthood. The onsets of both Sry and SRY-box 9 (Sox9) expressions as determined spatiotemporally by whole-mount immunohistochemistry in the B6N-XYPOS gonads occurred 2–3 tail somites later than those in B6N-XYB6 gonads, but earlier than those in B6J-XYPOS, respectively. It is possible that such a small difference in timing of the Sry expression underlies testicular development in our B6N-XYPOS. Our study is the first to histologically show the expression and ectopic localization of a female-related gene in the XYPOS testes and a male-related gene in the XYPOS ovaries. The results from these and previous experiments indicate that the interplay between genome variants, epigenetics and developmental gene regulation is crucial for testis development.  相似文献   
37.
The objective of the present study was to investigate the effect of dietary phospholipid (PL) level on growth and feed intake of juvenile amberjack ( Seriola dumerili ) fed non-fishmeal (non-FM) diet containing alternative protein sources; soybean protein isolate, tuna muscle by-product powder and krill meal. Three non-FM diets were prepared to contain three levels (14, 37 and 54 g kg−1 dry diet) of PL (soybean lecithin acetone insoluble, 886 g kg−1) and growth performance was monitored in a 30-day growth trial by using 2.6 g of fish. The results indicated that final body weight, weight gain and feed intake significantly increased with increasing dietary PL level. At the highest dietary PL level (54 g kg−1 dry diet), the fish consumed 14.8% and 10.2% as much feed as those fish fed diets containing 14 g kg−1 dry diet and 37 g kg−1 dry diet PL, respectively. An increasing tendency with increasing dietary PL level on feed efficiency was observed. In conclusion, the present study demonstrated that dietary PL supplementation could increase feed intake, and improve the growth of juvenile S. dumerili fed non-FM diets. Therefore, purified PL might be a good candidate to stimulate the growth of fish through enhancing the feed intake when they are fed diets containing alternative protein sources.  相似文献   
38.
This study was conducted to examine the effects of dietary ascorbic acid (AsA) and phospholipid (PL) and their interaction on growth, survival, and stress resistance in red sea bream larvae. Twenty‐six days old red sea bream were fed nine micro‐bound diets supplemented three levels of AsA (0, 800 and 1600 mg kg?1 diet) and PL (0, 20 and 40 g kg?1 diet) for 15 days. Dietary AsA and PL were both significant factors on survival rates. There was also an interaction between dietary AsA and PL on survival rate (P < 0.05). The larvae fed 800 or 1600 mg kg?1 AsA with 40 g kg?1 PL diets showed the highest survival rate, with values similar to those of the live‐food supplemented group. Stress resistance against low salinity exposure significantly increased with increased dietary level of AsA and PL. However, significant interaction of AsA and PL was not detected. The larvae fed 1600 mg kg?1 AsA with 40 g kg?1 PL diet showed the highest stress resistance among all diets, but it was not significantly different than that of larvae fed 800 mg kg?1 AsA with 40 g kg?1 PL diet. This study clearly demonstrated that combined use of AsA and PL can improve survival of 26–40 days posthatching red sea bream larvae. Moreover, the present study suggested that 800 mg kg?1 AsA with 40 g kg?1 PL in diet was needed for producing high quality seedling under the stressful conditions.  相似文献   
39.
Hyperplastic goblet cells and abundant mucus are significant characteristics of inflammatory colorectal polyps (ICRPs) in miniature dachshunds. In this study, selected mucin gene expressions and goblet cell proportions were evaluated in miniature dachshunds with ICRPs and in healthy dogs. Mucin 2 (MUC2) gene expression was not significantly different among the groups, whereas mucin 5AC (MUC5AC) gene expression was significantly higher in the polypoid lesions than in healthy colonic mucosa. Although the percentage of goblet cells in the upper crypt regions did not significantly differ between the groups, that in the lower crypt regions was significantly decreased in polypoid lesions. In conclusion, increased MUC5AC gene expression and goblet cell proportion changes may be associated with the pathogenesis of ICRPs.  相似文献   
40.
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