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91.
JAMES F. HARWOOD KEHUI CHEN HANS‐GEORG MÜLLER JANE‐LING WANG ROGER I. VARGAS JAMES R. CAREY 《Physiological Entomology》2013,38(1):81-88
The reproductive ability of female tephritids can be limited and prevented by denying access to host plants and restricting the dietary precursors of vitellogenesis. The mechanisms underlying the delayed egg production in each case are initiated by different physiological processes that are anticipated to have dissimilar effects on lifespan and reproductive ability later in life. The egg‐laying abilities of laboratory‐reared females of the Mediterranean fruit fly (Ceratitis capitata Wiedmann) and melon fly (Bactrocera cucurbitae Coquillett) from Hawaii are delayed or suppressed by limiting access to host fruits and dietary protein. In each case, this is expected to prevent the loss of lifespan associated with reproduction until protein or hosts are introduced. Two trends are observed in each species: first, access to protein at eclosion leads to a greater probability of survival and a higher reproductive ability than if it is delayed and, second, delayed host access reduces lifetime reproductive ability without improving life expectancy. When host access and protein availability are delayed, the rate of reproductive senescence is reduced in the medfly, whereas the rate of reproductive senescence is generally increased in the melon fly. Overall, delaying reproduction lowers the fitness of females by constraining their fecundity for the remainder of the lifespan without extending the lifespan. © 2013 The Royal Entomological Society 相似文献
92.
Kinji Endo Yōko Umeyama Junko Nakajima Hiroyasu Kawai 《Bioscience, biotechnology, and biochemistry》2013,77(7):1545-1551
Three kinds of nuclease preparations, each of which having both endonuclease activity that formed 5′-mononucleotides and 3′-nucleotidase activity, were separated and partially purified from Shii-take, Lentinus edodes. Both enzyme activities of each preparation showed a similar thermostability and electrophoretic mobility on Polyacrylamide gel, and a competitive relationship was observed between RNA and 3′-AMP in their enzyme reactions. From these results, it is concluded that both enzyme activities of these three preparations reside in a single protein, respectively. They resemble one another in substrate specificity, cleavage pattern of RNA and thermostability, but are distinguishable from one another by molecular weight, electrophoretic mobility and optimum pH for degradation of RNA. 相似文献
93.
《Nucleosides, nucleotides & nucleic acids》2013,32(6-7):873-877
The procedure based on binding of nucleic acids with glass surface in presence of chaotropic salts was adapted for efficient isolation of 100–10000 b.p. DNA fragments and 50–10,000 b. RNA fragments. The method provide 90% and 85% efficacy of isolation of 100 b.p. DNA and 100 b. RNA fragments respectively. High molecular weight nucleic acids are isolated with 98% efficacy. Isolated nucleic acids are free from contaminations, influencing nucleic acids modifying enzymes and fluorochromes. The method is rapid, simple and cost‐effective. 相似文献
94.
Data are presented suggesting that birds have evolved eggs with shells containing different structures (numbers of mammillae per unit of inner eggshell surface area, i.e., mammillary densities) to cope up with different calcium requirements imposed by different growth rates and modes of development. Precocial bird species grow slowly, but have high mammillary density, while altricial bird species grow rapidly, but have low mammillary density. These results suggest an adaptation associated with growth rate and mode of development and show, moreover, that the mammillary layer is indicative of the breeding biology of the bird. J. Morphol. 2012. © 2011 Wiley Periodicals, Inc. 相似文献
95.
96.
In conventional gene flow theory the rate of genetic gain is calculated as the summed products of genetic selection differential and asymptotic proportion of genes deriving from sex-age groups. Recent studies have shown that asymptotic proportions of genes predicted from conventional gene flow theory may deviate considerably from true proportions. However, the rate of genetic gain predicted from conventional gene flow theory was accurate. The current note shows that the connection between asymptotic proportions of genes and rate of genetic gain that is embodied in conventional gene flow theory is invalid, even though genetic gain may be predicted correctly from it. 相似文献
97.
98.
Chondrogenic differentiation of mesenchymal cells is generally thought to be initiated by the inductive action of specific
growth factors and depends on intimate cell-cell interactions. The aim of our investigation was to characterize the influences
of basic fibroblast growth factor (bFGF) and ferroussulfate (FeSO4) on proliferation and differentiation of human articular chondrocytes (HAC). This is the first report of the effects of FeSO4 on chondrogenesis of HAC. Multiplied chondrocytes of hip and shoulder joints were cultured in chondrocyte growth medium supplemented
with bFGF, FeSO4, or both bFGF + FeSO4 for4weeks. A 20 μl aliquot of a cell suspension containing2 × 107 cells ml−1 was delivered onto each well of 24-well tissue culture plates. Cells cultured with the growth medium only was used as a control.
Alamar blue and alcian blue staining were done to determine the chondrocyte proliferation and differentiation, respectively,
after 4 weeks. The samples exposed to bFGF, FeSO4, and combination of both indicated sufficient cell proliferation similar to the control level. Differentiations of the HAC
exposed to bFGF, FeSO4,and bFGF + FeSO4 were 1.2-, 2.0-, and 2.2-fold of the control, respectively. Therefore, chondrocyte differentiation was significantly enhanced
by the addition of FeSO4 andbFGF + FeSO4. The combined effects of bFGF and FeSO4 were additive, rather than synergistic. These results suggest that treatment with ferrous sulfate alone or in combination
with basic fibroblast growth factor etc, is a powerful tool to promote the differentiation of HAC for the clinical application.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
99.
Josep C. Jiménez-Chillarón Rubén Díaz Débora Martínez Thais Pentinat Marta Ramón-Krauel Sílvia Ribó Torsten Plösch 《Biochimie》2012
Nutrition plays a key role in many aspects of health and dietary imbalances are major determinants of chronic diseases including cardiovascular disease, obesity, diabetes and cancer. Adequate nutrition is particularly essential during critical periods in early life (both pre- and postnatal). In this regard, there is extensive epidemiologic and experimental data showing that early sub-optimal nutrition can have health consequences several decades later. 相似文献
100.
Jaap J. Beintema 《Journal of the history of biology》2008,41(1):159-165
Albert (von) Szent-Györgyi started his studies on biological oxidation processes – which also resulted in the discovery of vitamin C, for which he received the Nobel Price in 1937 – in the Laboratory of Physiology of the University in Groningen in 1922–1926. These studies were later continued in Cambridge (UK) and Szeged (Hungary). When he had already received the invitation as well as the financial means to come and work in Cambridge, he still did experiments in Groningen to find out whether the adrenal extract, isolated by him and later found to be a major source of vitamin C, contained the hormone essential for the survival of cats whose adrenals were removed. He was rather upset by the negative results of this experiment, judging by the recollections of a former student of his. This history constitutes an interesting example of the difference between serendipitous discovery and planned invention. 相似文献