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1.
高慰曾 《昆虫学报》1965,(6):603-609
本文对东亚飞蝗两型的卵、蝻及成虫的形态以及成虫的生殖、消化两系统各器官的长度进行了比较,试图明确两型在形态与解剖方面的差异。 研究方法 所用材料,除室内试验用卵系来自山东德州内涝蝗区(后经在北京室内饲养至第三代)外,其他省采自河南浚县蝗区。群居型蝻及成虫均系自野外采得一、二龄蝻,置于田间铁纱笼内(笼容积为33×33×33立方公分)饲养获得。每笼放幼蝻300头。散居型蝻  相似文献   
2.
Congenital stationary night blindness (CSNB) is an inherited and non‐progressive retinal dysfunction. Here, we present the crystal structure of CSNB‐causing T94I2.61 rhodopsin in the active conformation at 2.3 Å resolution. The introduced hydrophobic side chain prolongs the lifetime of the G protein activating metarhodopsin‐II state by establishing a direct van der Waals contact with K2967.43, the site of retinal attachment. This is in stark contrast to the light‐activated state of the CSNB‐causing G90D2.57 mutation, where the charged mutation forms a salt bridge with K2967.43. To find the common denominator between these two functional modifications, we combined our structural data with a kinetic biochemical analysis and molecular dynamics simulations. Our results indicate that both the charged G90D2.57 and the hydrophobic T94I2.61 mutation alter the dark state by weakening the interaction between the Schiff base (SB) and its counterion E1133.28. We propose that this interference with the tight regulation of the dim light photoreceptor rhodopsin increases background noise in the visual system and causes the loss of night vision characteristic for CSNB patients.  相似文献   
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SYNOPSIS. The life histories of many vertebrates include complex,postembryonic developmental pathways that involve morphologicaland physiological changes that adapt juveniles to a new habitat.A survey of such developmental pathways, including lamprey metamorphosis,salmonid smoltification, and anuran metamorphosis, reveals acommon strategy of lipid metabolism consisting of two distinctphases. The first phase is characterized by lipid accumulationin storage sites and resultsfrom lipogenesis prevailing overlipolysis. The second phase is characterized by lipid depletionfrom storage sites and results from lipolysis prevailing overlipogenesis. Regulation of lipid deposition and lipid mobilizationis essential for ensuring availability of lipid during timesof need. Lipogenesis is promoted by insulin and, in lampreyand anurans, also by thyroid hormones. Lipolysis is promotedby a number of hormones, including prolactin, growth hormone,adrenocorticotropic hormone, corticosteroids, somatostatins,and thyroid hormones. The coordinate regulation of development-associatedchanges in lipid metabolism results from interactions amonghormones and other internal and environmental cues.  相似文献   
4.
Upon activation, an internal hydrostatic pressure develops within the Fundulus egg, and compresses the egg proper to a reduced volume. When the perivitelline pressure is abolished by a highly hypertonic sucrose solution, the egg volume increases. As sucrose penetrates the chorion, the volume again decreases. The relation between P and V in these conditions is inverse, and approximates a rectangular hyperbola. The limiting factor causing most of the deviation is shown to be the incompressible fraction. It is concluded that the volume of the egg proper is controlled by the perivitelline pressure, and that the effect of hypertonic sucrose solution is exerted by lowering the pressure and thereby increasing membrane permeability non-specifically. It is also shown that some permanent alterations occur within the plasma membrane during activation that reduce the permeance, and thereby, increase the incompressible fraction.  相似文献   
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Stratification at 0 °C accelerates subsequent germinationof seed of Pinus radiata D. Don when transferred to 25 °C;the effect of low temperature is on the megagametophyte, notthe embryo. Organic acids, sucrose, and organic phosphates accumulatein the seed during stratification but lipase and invertase havelow activities which do not increase during treatment at 0 °C.We conclude that this accumulation of metabolites underliesthe increase in rate of germination of stratified seed. Treatingseeds at 0 °C rather than 5 °C separates effects dueto stratification and growth.  相似文献   
8.
蝇类在世界各地的分布极为广泛,种类繁多,每年出现季节较长,与人群接触极为频繁,因而常为传染各病的媒介,在我国已往对蝇类的分布及其与传染病的关系,所作的调查研究并不太多。姚、袁等氏(1929)在北京调查结果,发现在多数蝇类的体内含有大肠杆菌,且自肠内分离出痢疾杆菌,以及结肠内阿米巴、赤痢内阿米巴包囊,及鞭毛虫,纤  相似文献   
9.
前 言 为了预防疟疾,流行性乙型脑炎及其他蚊类传染的疾病,作好“除四害”的工作,必须首先了解当地蚊种、滋生地点及越冬情况等生态学的问题,才能制定出切实可行,经济有效的灭蚊计划。过去我国文献关于保定蚊类情况,尚少报导,所以我们在1954—1955年作了一些调查工作,可以作为今后进一步研究的基础。  相似文献   
10.
1961年8月,在北京郊区农药厂附近采集了一些家蝇,经过室内培养后,发现有7个白眼家蝇,随即进行分离培养,成为白眼变种品系。 白眼家蝇变种在国内还是第一次发现,国外亦只是近二三年来才有报道(Sullivan及Hiroyoshi,1960;Tsukamoto,1961),他们发现的变种可能属于 Musca domestica domes-tica L.而我们发现的是属于 Musca domestica vicina M.。  相似文献   
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