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31.
The state of the art for thermophilic UASB reactors is discussed focusing on the start-up of UASB reactors, the influence of the waste water composition and temperature on the development and maintenance of thermophilic granules, and the microbial composition and structure of thermophilic granules.  相似文献   
32.
Neurofilament (NF) proteins are distributed in a diminishing proximodistal gradient along rat sciatic nerve when compared with total noncollagen or other proteins in nerve. About a twofold decline of NF proteins can be detected by quantitating nerve proteins that have been separated by gel electrophoresis. A similar decrease of immunoreactivity to each NF subunit is seen in distal nerve segments when noncollagen nerve proteins are immunoblotted. Parallel decreases occur in all three NF proteins, thereby maintaining neurofilament subunit stoichiometry along the neuraxis. The same NF gradient can be detected when the NF contents in nerve branches to the gluteus and gastrocnemius muscles are compared with each other and with those in nerve segments taken from the same proximodistal levels of the parent sciatic nerve. The gradient of NF proteins increases during postnatal development and is readily detected by postnatal day 16. During the same period of development, the heavy NF subunit appears for the first time and is rapidly incorporated throughout the sciatic nerve. Hence, the NF gradient becomes manifest during the development and maturation of the adult form of the axonal cytoskeleton. The basis for the proximodistal gradient of NF proteins in peripheral nerve is presently unknown. The extent of the gradient cannot be accounted for on the basis of diminishing numbers of nerve fibers or increasing amounts of other nerve proteins, e.g., collagen, in distal nerve. An alternative interpretation is that the gradient reflects a low level of NF protein turnover during axonal transport.  相似文献   
33.
Abstract. Most colonies (thirty-five out of thirty-seven) of the ant Gnamptogenys menadensis (Mayr) (Hymenoptera: Formicidae: Ponerinae) lack queens. Mated workers produce reproductive eggs, whereas virgin workers can lay only smaller trophic eggs (350 ovipositions observed). These two egg types are morphologically distinct (e.g. in the pattern of oogenesis and ultrastructure of membranes and micropyle) and relate to different ovarian characteristics (ovariole length, number of yolky oocytes and yellow bodies). When reproductives are removed, a small number of virgin workers switch to producing reproductive eggs, although only 3% of these develop into larvae. Once workers are mated, up to 50% of their eggs develop further. Trophic eggs are generally absent in social insects lacking physical castes, and we review adaptive explanations of its occurrence in G. menadensis .  相似文献   
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The distribution of cytosolic activity of nicotinamide:S-adenosylmethionine methyltransferase (nicotinamide methylase, EC 2.1.1.1) in normal tissues from adult rat and mouse and in tumors and the change in the enzyme activity during the the development of rat tissues were studied. (1) Rat liver exhibited the highest nicotinamide methylase activity among all adult tissues tested; other rat tissues, like adrenal, pancreas, kidney, brain and mouse tissues, had only less than 15% of the adult rat liver activity. (2) 3 days before birth, fetal liver showed a very low nicotinamide methylase activity (2% of adult rat liver), which, however, increased already 1 day before birth and reached the adult level on the day 28 after birth. (3) In a variety of hepatomas and ascites tumors, an inverse correlation, with some exceptions, between tumor growth rate and nicotinamide methylase activity could be seen. In all hepatomas, with the exception of Morris hepatoma 5123tc, nicotinamide methylase activity was significantly decreased in comparison to normal adult rat liver. The highly malignant Zajdela hepatoma, Yoshida sarcoma, sarcoma 180 and Ehrlich ascites tumor methylated nicotinamide only at a negligibly low rate. (4) Cultured RLC cells (an established rat liver cell line) from the stationary growth phase or G1-arrested RLC cells had about half of the adult rat liver activity, yet the activity was 70% higher than that of the logarithmically growing RLC cells.  相似文献   
36.
The thyroid is a bilobated endocrine gland localized at the base of the neck, producing the thyroid hormones T3, T4, and calcitonin. T3 and T4 are produced by differentiated thyrocytes, organized in closed spheres called follicles, while calcitonin is synthesized by C-cells, interspersed in between the follicles and a dense network of blood capillaries. Although adult thyroid architecture and functions have been extensively described and studied, the formation of the “angio-follicular” units, the distribution of C-cells in the parenchyma and the paracrine communications between epithelial and endothelial cells is far from being understood.This method describes the sequential steps of mouse embryonic thyroid anlagen dissection and its culture on semiporous filters or on microscopy plastic slides. Within a period of four days, this culture system faithfully recapitulates in vivo thyroid development. Indeed, (i) bilobation of the organ occurs (for e12.5 explants), (ii) thyrocytes precursors organize into follicles and polarize, (iii) thyrocytes and C-cells differentiate, and (iv) endothelial cells present in the microdissected tissue proliferate, migrate into the thyroid lobes, and closely associate with the epithelial cells, as they do in vivo.Thyroid tissues can be obtained from wild type, knockout or fluorescent transgenic embryos. Moreover, explants culture can be manipulated by addition of inhibitors, blocking antibodies, growth factors, or even cells or conditioned medium. Ex vivo development can be analyzed in real-time, or at any time of the culture by immunostaining and RT-qPCR.In conclusion, thyroid explant culture combined with downstream whole-mount or on sections imaging and gene expression profiling provides a powerful system for manipulating and studying morphogenetic and differentiation events of thyroid organogenesis.  相似文献   
37.
Thoracic aortic dissection (TAD) is an aortic disease associated with dysregulated extracellular matrix composition and de-differentiation of vascular smooth muscle cells (SMCs). Growth Differentiation Factor 11 (GDF11) is a member of transforming growth factor β (TGF-β) superfamily associated with cardiovascular diseases. The present study attempted to investigate the expression of GDF11 in TAD and its effects on aortic SMC phenotype transition. GDF11 level was found lower in the ascending thoracic aortas of TAD patients than healthy aortas. The mouse model of TAD was established by β-aminopropionitrile monofumarate (BAPN) combined with angiotensin II (Ang II). The expression of GDF11 was also decreased in thoracic aortic tissues accompanied with increased inflammation, arteriectasis and elastin degradation in TAD mice. Administration of GDF11 mitigated these aortic lesions and improved the survival rate of mice. Exogenous GDF11 and adeno-associated virus type 2 (AAV-2)-mediated GDF11 overexpression increased the expression of contractile proteins including ACTA2, SM22α and myosin heavy chain 11 (MYH11) and decreased synthetic markers including osteopontin and fibronectin 1 (FN1), indicating that GDF11 might inhibit SMC phenotype transition and maintain its contractile state. Moreover, GDF11 inhibited the production of matrix metalloproteinase (MMP)-2, 3, 9 in aortic SMCs. The canonical TGF-β (Smad2/3) signalling was enhanced by GDF11, while its inhibition suppressed the inhibitory effects of GDF11 on SMC de-differentiation and MMP production in vitro. Therefore, we demonstrate that GDF11 may contribute to TAD alleviation via inhibiting inflammation and MMP activity, and promoting the transition of aortic SMCs towards a contractile phenotype, which provides a therapeutic target for TAD.  相似文献   
38.
Chemokine C-C motif ligand 7 (CCL7), a member of CC chemokine subfamily, plays pivotal roles in numerous inflammatory diseases. Hyper-activation of inflammation is an important characteristic of abdominal aortic aneurysm (AAA). Therefore, in the present study, we aimed to determine the effect of CCL7 on AAA formation. CCL7 abundance in aortic tissue and macrophage infiltration were both increased in angiotensin II (Ang II)-induced AAA mice. Ex vivo, CCL7 promoted macrophage polarization towards M1 phenotype. This effect was reversed by the blockage of CCR1, a receptor of CCL7. CCL7 up-regulated JAK2/STAT1 protein level in macrophage, and CCL7-induced M1 activation was suppressed by JAK2/STAT1 pathway inhibition. To verify the effect of CCL7 on AAA in vivo, either CCL7-neutralizing antibody (CCL7-nAb) or vehicles were intraperitoneally injected 24 hours prior to Ang II infusion and subsequently every three days for 4 weeks. CCL7-nAb administration significantly attenuated Ang II-induced luminal and external dilation as well as pathological remodelling. Immunostaining showed that CCL7-nAb administration significantly decreased aneurysmal macrophage infiltration. In conclusion, CCL7 contributed to Ang II-induced AAA by promoting M1 phenotype of macrophage through CCR1/JAK2/STAT1 signalling pathway.  相似文献   
39.
冯思远  赵文武  华廷  王涵 《生态学报》2021,41(20):7955-7964
“SDGs加速行动”是国际组织、政府部门、私营机构和其他利益攸关方为加快落实2030年可持续发展议程采取的全球行动。2019年联合国可持续发展目标峰会后,政府、国际组织、私营部门等提出了214项SDGs加速行动。2019年爆发的新型冠状病毒肺炎(Corona Virus Disease 2019,COVID-19)对实现可持续发展目标带来了系列影响,后疫情时代如何推动全球SDGs加速行动的实施成为重要的问题。对可持续发展评估报告(2019)和可持续发展目标加速行动等政策文件进行信息提取,建立加速行动匹配性指数模型和各国应对新冠疫情的恢复力指数模型,根据匹配性-恢复力分类体系将各国按照17项可持续发展目标分为9类,为推动后疫情时代全球可持续发展目标加速行动提供支撑。研究发现:(1)现有可持续发展目标加速行动的实施与区域需求不匹配,且这种不匹配的情况在COVID-19爆发前已经出现;(2)加速行动的实施受限于现有可持续发展水平和国家经济基础,区域关注的可持续发展目标与其自然地理位置和社会发展水平有着密切的关系,多边组织机构和其他利益攸关方需要在发展中国家大力推动可持续发展加速行动;(3)下一步实施加速行动需要加强国际间的合作,根据分类框架和可持续发展目标的关联关系,分重点推进加速行动的实施,完善可持续发展指标监测体系,分类设立后疫情时代不同时期的阶段目标,分阶段循序渐进,定期反馈追踪,以在2030年促进17项可持续目标的实现。  相似文献   
40.
A micromethod for the quantitative analysis of caffeine present in small quantities (100 μl) of whole blood is described. It is based on the gas chromatographic—mass spectrometric analysis of chloroform extracts of biological samples. The method is relatively simple, rapid, specific and sensitive, as little as 20 ng of caffeine can be measured.  相似文献   
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