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排序方式: 共有366条查询结果,搜索用时 93 毫秒
1.
Eliot C. Bush Anne E. Clark Chris M. DeBoever Lillian E. Haynes Sidra Hussain Singer Ma Matthew M. McDermott Adam M. Novak John S. Wentworth 《PloS one》2012,7(11)
A significant proportion of enzymes display cooperativity in binding ligand molecules, and such effects have an important impact on metabolic regulation. This is easiest to understand in the case of positive cooperativity. Sharp responses to changes in metabolite concentrations can allow organisms to better respond to environmental changes and maintain metabolic homeostasis. However, despite the fact that negative cooperativity is almost as common as positive, it has been harder to imagine what advantages it provides. Here we use computational models to explore the utility of negative cooperativity in one particular context: that of an inhibitor binding to an enzyme. We identify several factors which may contribute, and show that acting together they can make negative cooperativity advantageous. 相似文献
2.
Waqar Ahmad Bushra Ijaz Khadija Shabbiri Fayyaz Ahmed Sidra Rehman 《Journal of biomedical science》2017,24(1):76
Reactive oxidative species (ROS) toxicity remains an undisputed cause and link between Alzheimer’s disease (AD) and Type-2 Diabetes Mellitus (T2DM). Patients with both AD and T2DM have damaged, oxidized DNA, RNA, protein and lipid products that can be used as possible disease progression markers. Although the oxidative stress has been anticipated as a main cause in promoting both AD and T2DM, multiple pathways could be involved in ROS production. The focus of this review is to summarize the mechanisms involved in ROS production and their possible association with AD and T2DM pathogenesis and progression. We have also highlighted the role of current treatments that can be linked with reduced oxidative stress and damage in AD and T2DM. 相似文献
3.
4.
Salt tolerance ofEchinochloa crusgalli was studied using gravel culture with root medium electrical conductivity between 3 to 25 dS m-1. Salinity depressed germination and shoot yield. A 50 % reduction in shoot yield occurred at 15.9 dS m-1. The plant was able to maintain its tissue water content and K concentration in the tissue water while Na, Ca and Cl increased
and Mg decreased with increasing root zone salinity. 相似文献
5.
Infection by Macrophonina phaseolina was substantially reduced following treatment of sunflower and mungbean seeds with Trichoderma harzianum, Gliocladium virens, Paecilomyces lilacinus or Streptomyces sp. which gave promising control of charcoal rot disease. Treatment of mungbean seeds with Rhizobium meliloti also gave good disease control. 相似文献
6.
This study reports the effect of salinity and inoculation on growth, ion uptake and nitrogen fixation byVigna radiata. A soil ECe level of 7.5 dS m−1 was quite detrimental causing about 60% decline in dry matter and grain yield of mungbean plants whereas a soil ECe level of 10.0 dS m−1 was almost toxic. In contrast most of the studied strains of Rhizobium were salt tolerant. Nevertheless, nodulation, nitrogen
fixation and total nitrogen concentration in the plant was drastically affected at high salt concentration. A noticeable decline
in acetylene reduction activity occurred when salinity level increased to 7.5 dS m−1. 相似文献
7.
The effect of NH
4
+
on the regulation of NO
3
–
and NO
2
–
transport systems in roots of intact barley (Hordeum vulgareL.) seedlings grown in NO
3
–
or NO
2
–
was studied. Ammonium partially inhibited induction of both transport systems. The inhibition was less severe in NO
2
–
-fed than in NO
3
–
-fed seedlings, presumably due to lower uptake of NH
4
+
in the presence of NO
2
–
. In seedlings pretreated with NH
4
+
subsequent induction was inhibited only when NH
4
+
was also present during induction, even though pretreated roots accumulated high levels of NH
4
+
. This indicates that inhibition may be regulated by NH
4
+
concentration in the cytoplasm rather than its total accumulation in roots. L-Methionine sulfoximine did not relieve the inhibition by NH
4
+
, suggesting that inhibition is caused by NH
4
+
itself rather than by its assimilation product(s). Ammonium inhibited subsequent expression of NO
3
–
transport activity similarly in roots grown in 0.1, 1.0, or 10 mM NO
3
–
for 24 h (steady-state phase) or 4 d (decline phase), indicating that it has a direct, rather than general feedback effect. Induction of the NO
3
–
transport system was about twice as sensitive to NH
4
+
as compared to the NO
2
–
transport system. This may relate to higher turnover rates of membraneassociated NO
3
–
-transport proteins.Abbreviations Mes
2(N-morpholino)ethanesulfonic acid
- MSO
L-methionine sulfoximine 相似文献
8.
Synthesis of lactoferrin and casein by the bovine mammary gland was determined in an experimental model where lactation was maintained in one mammary half, while involution was induced in the contralateral half. Culture of explants with prolactin had no consistent effect on synthesis of casein or lactoferrin in tissue from either mammary half. Endotoxin and tumor necrosis factor-α generally decreased synthesis of casein and lactoferrin, suggesting that these inflammatory mediators are not directly responsible for increasing lactoferrin synthesis during mammary inflammation or involution. Synthesis of lactoferrin was increased and casein decreased in the involuting mammary half vs. the lactating half. These results suggest that local factors in the mammary gland play a role in the regulation of lactoferrin synthesis during involution. 相似文献
9.
The endoplasmic reticulum (ER) membrane protein complex (EMC) is essential for the insertion of a wide variety of transmembrane proteins into the plasma membrane across cell types. Each EMC is composed of Emc1-7, Emc10, and either Emc8 or Emc9. Recent human genetics studies have implicated variants in EMC genes as the basis for a group of human congenital diseases. The patient phenotypes are varied but appear to affect a subset of tissues more prominently than others. Namely, craniofacial development seems to be commonly affected. We previously developed an array of assays in Xenopus tropicalis to assess the effects of emc1 depletion on the neural crest, craniofacial cartilage, and neuromuscular function. We sought to extend this approach to additional EMC components identified in patients with congenital malformations. Through this approach, we determine that EMC9 and EMC10 are important for neural crest development and the development of craniofacial structures. The phenotypes observed in patients and our Xenopus model phenotypes similar to EMC1 loss of function likely due to a similar mechanism of dysfunction in transmembrane protein topogenesis. 相似文献
10.
Munir Ozturk Mert Metin Volkan Altay Tomonori Kawano Alvina Gul Bengu Turkyilmaz Unal Dilek Unal Rouf Ahmad Bhat Moonisa Aslam Dervash Kristina Toderich Esra Koc Pedro Garcia Caparros leeb Shahzadi 《Phyton》2023,92(1):165-192
Aluminum is an abundant metal in the earth’s crust that turns out to be toxic in acidic environments. Many plants are affected by the presence of aluminum at the whole plant level, at the organ level, and at the cellular level. Tobacco as a cash crop (Nicotiana tabacum L.) is a widely cultivated plant worldwide and is also a good model organism for research. Although there are many articles on Al-phytotoxicity in the literature, reviews on a single species that are economically and scientifically important are limited. In this article, we not only provide the biology associated with tobacco Al-toxicity, but also some essential information regarding the effects of this metal on other plant species (even animals). This review provides information on aluminum localization and uptake process by different staining techniques, as well as the effects of its toxicity at different compartment levels and the physiological consequences derived from them. In addition, molecular studies in recent years have reported specific responses to Al toxicity, such as overexpression of various protective proteins. Besides, this review discusses data on various organelle-based responses, cell death, and other mechanisms, data on tobacco plants and other kingdoms relevant to these studies. 相似文献