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81.
Indrikis Krams Dina Cirule Valerija Suraka Tatjana Krama Markus J. Rantala Gary Ramey 《Functional ecology》2010,24(1):172-177
1. In a seasonal environment, subcutaneous energy reserves of resident animals often increase in winter and decline again in summer reflecting gradual seasonal changes in their fattening strategies. We studied changes in body reserves of wintering great tits in relation to their dominance status under two contrasting temperature regimes to see whether individuals are capable of optimizing their body mass even under extreme environmental conditions.
2. We predicted that dominant individuals will carry a lesser amount of body reserves than subordinate great tits under mild conditions and that the body reserves of the same dominant individuals will increase and exceed the amount of reserves of subordinates under conditions of extremely low ambient temperatures, when ambient temperature dropped down to −37 °C.
3. The results confirmed the predictions showing that dominant great tits responded to the rising risk of starvation under low temperatures by increasing their body reserves and this was done at the expense of their safety.
4. Removal experiments revealed that lower body reserves of subordinate flock members are due to the increased intraspecific competition for food under low ambient temperatures.
5. Our results also showed that fattening strategies of great tits may change much quicker than previously considered, reflecting an adaptive role of winter fattening which is sensitive to changes in ambient temperatures. 相似文献
2. We predicted that dominant individuals will carry a lesser amount of body reserves than subordinate great tits under mild conditions and that the body reserves of the same dominant individuals will increase and exceed the amount of reserves of subordinates under conditions of extremely low ambient temperatures, when ambient temperature dropped down to −37 °C.
3. The results confirmed the predictions showing that dominant great tits responded to the rising risk of starvation under low temperatures by increasing their body reserves and this was done at the expense of their safety.
4. Removal experiments revealed that lower body reserves of subordinate flock members are due to the increased intraspecific competition for food under low ambient temperatures.
5. Our results also showed that fattening strategies of great tits may change much quicker than previously considered, reflecting an adaptive role of winter fattening which is sensitive to changes in ambient temperatures. 相似文献
82.
Ilan Hammel Tanya Shoichetman Dina Amihai Stephen J. Galli Ehud Skutelsky 《Cell and tissue research》2010,339(3):561-570
We used the egg avidin gold complex as a polycationic probe for the localization of negatively charged sites in the secretory
granules of mouse mast cells. We compared the binding of this reagent to mast cell granules in wild-type mice and in congenic
brachymorphic mice in which mast cell secretory granules contained undersulfated proteoglycans. We localized anionic sites
by post-embedding labeling of thin sections of mouse skin and tongue tissues fixed in Karnovsky’s fixative and OsO4 and embedded in Araldite. Transmission electron microscopy revealed that the mast cell granules of bm/bm mice had a lower optical density than those of wild-type mice (P<0.001) and a lower avidin gold binding density (by approximately 50%, P<0.001). The latter result provided additional evidence that the contents of mast cell granules in bm/bm mice were less highly sulfated than in those of wild-type mice. In both wild-type and bm/bm mast cells, the distribution of granule equivalent volumes was multimodal, but the unit granule volume was approximately
19% lower in bm/bm cells than in wild-type cells (P<0.05). Thus, bm/bm mast cells develop secretory granules that differ from those of wild-type mice in exhibiting a lower optical density and
slightly smaller unit granules, however the processes that contribute to granule maturation and granule-granule fusion in
mast cells are operative in bm/bm cells. 相似文献
83.
84.
Maria E. Silva Serra Dina Murtinho Albertino Goth António M. D'A. Rocha Gonsalves Paulo E. Abreu Alberto A. C. C. Pais 《Chirality》2010,22(4):425-431
New chiral salen ligands were prepared by the ultrasound‐irradiated condensation of optically active (1R, 3S)‐1,2,2‐trimethyl‐1,3‐diaminocyclopentane with aromatic 1‐hydroxyaldehydes. The ultrasound‐mediated process is more convenient due to shorter reaction times, energy economy, and easier isolation of the products. The in situ formed Ti(IV)(salen) complexes, evaluated as catalysts in the enantioselective trimethylsilylcyanation of benzaldehyde, were found to be efficient for this process, originating the corresponding product in high yields (72–99%) and selectivities of up to 79%. The lowest energy transition states were determined by computational studies. These results were in qualitative agreement with the experimentally observed ones. Chirality, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
85.
Prospects of yeast systems biology for human health: integrating lipid, protein and energy metabolism 总被引:2,自引:0,他引:2
The yeast Saccharomyces cerevisiae is a widely used model organism for studying cell biology, metabolism, cell cycle and signal transduction. Many regulatory pathways are conserved between this yeast and humans, and it is therefore possible to study pathways that are involved in disease development in a model organism that is easy to manipulate and that allows for detailed molecular studies. Here, we briefly review pathways involved in lipid metabolism and its regulation, the regulatory network of general metabolic regulator Snf1 (and its human homologue AMPK) and the proteostasis network with its link to stress and cell death. All the mentioned pathways can be used as model systems for the study of homologous pathways in human cells and a failure in these pathways is directly linked to several human diseases such as the metabolic syndrome and neurodegeneration. We demonstrate how different yeast pathways are conserved in humans, and we discuss the possibilities of using the systems biology approach to study and compare the pathways of relevance with the objective to generate hypotheses and gain new insights. 相似文献
86.
The purpose of this study was to prepare sublingual tablets, containing the antiasthmatic drug ketotifen fumarate which suffers an extensive first-pass effect, using the fast-melt granulation technique. The powder mixtures containing the drug were agglomerated using a blend of polyethylene glycol 400 and 6000 as meltable hydrophilic binders. Granular mannitol or granular mannitol/sucrose mixture were used as fillers. A mechanical mixer was used to prepare the granules at 40°C. The method involved no water or organic solvents, which are used in conventional granulation, and hence no drying step was included, which saved time. Twelve formulations were prepared and characterized using official and non official tests. Three formulations showed the best results and were subjected to an ex vivo permeation study using excised chicken cheek pouches. The formulation F4I possessed the highest permeation coefficient due to the presence of the permeation enhancer (polyethylene glycol) in an amount which allowed maximum drug permeation, and was subjected to a pharmacokinetic study using rabbits as an animal model. The bioavailability of F4I was significantly higher than that of a commercially available dosage form (Zaditen® solution-Novartis Pharma-Egypt) (p > 0.05). Thus, fast-melt granulation allowed for rapid tablet disintegration and an enhanced permeation of the drug through the sublingual mucosa, resulting in increased bioavailabililty.Key words: chicken pouches, fast-melt granulation, ketotifen fumarate, permeation, sublingual tablet, Zaditen® 相似文献
87.
Haider Karar Muhammad Amjad Bashir Abdul Basit Sagheer Atta Ahmad Ali Anjum Ali Bakhsh Arif Hussain Abid Hameed Yong Wang Reem Atalla Alajmi Dina M. Metwally Muhammad Imran 《Saudi Journal of Biological Sciences》2021,28(4):2366-2373
A study was performed to assess the preference of fourteen mango cultivars for fruit flies and their management by bagging. So the choice of Tephritid flies to mango cultivars during fruiting phase is crucial. Fourteen different cultivars of mango viz., ‘Dusehri’, ‘Malda’, ‘Langra’ early cultivars, ‘Chaunsa’, ‘Fajri Klan’, ‘Sensation’ medium whereas ‘Sanglakhi’, ‘Retaul-12’, ‘Mehmood Khan’, ‘Tukhmi’, ‘Kala Chaunsa’, ‘Chitta Chaunsa’, ‘Dai Wala’ and ‘Sobey De Ting’ late cultivars were assessed for their suitability for fruit flies. The results indicate that the population density of fruit flies was higher on late cultivars like ‘Sanglakhi’ (20.61 percent), ‘Mehmood Khan’ (20.22 percent) and ‘Reutal-12’ (19.92 percent) were proved to be highly susceptible to fruit flies. Among these the cultivar ‘Reutal-12’ was selected being commercial and future cultivar for the management of fruit flies through bagging. The results reported that the attack of tephritid fruit flies and other insect pests were zero in bagged fruits as compared with control. It was further recorded that the bagged fruits has maximum average fruit weight i.e. 203.50 and 197.83 g per fruit was noted in those treatments where butter paper bag and brown paper bag was wrapped with better coloration as compared with un-bagged fruit with 159.5 g per fruit. Similarly, on an average fruit length were more i.e. 90.17, 91.33 mm in bagged fruit and 85.33 in un-bagged fruits. Furthermore, bagged fruits have zero incidence of disease with reduced fruit crack, fruit sunburn, mechanical damage, bird damage, fruit blemished and agrochemical residues on the fruit. So, it is concluded that the special attention should be given on ‘Reutal-12’ for the management of fruit flies when devising an IPM program for the control of fruit flies. Further, bagging has proved to be the good agricultural practices for the production of quality mango. 相似文献
88.
Saswati Nayak Radha Prasanna Boddupalli M. Prasanna Dina B. Sahoo 《World journal of microbiology & biotechnology》2007,23(11):1575-1584
A set of 24 strains belonging to the genus Anabaena (Phylum Cyanobacteria), isolated from diverse geographic locations in India, were evaluated along with three International
type strains of Anabaena (ATCC 29414, ATCC 29208 and ATCC 27899) for their morphological, physiological and biochemical diversity. The morphological
dataset, consisting of 58 variants for 15 characters, and SDS-PAGE protein profiles comprising 17 polymorphic bands were utilized
to differentiate the selected Anabaena strains and explore the patterns of diversity through cluster analysis. Physiological and biochemical characterization with
respect to nitrogen fixation and accumulation of chlorophyll and phycobiliproteins led to the identification of some highly
promising Anabaena strains for use as biofertilizers and source of pigments. The study highlighted the tremendous inter and intraspecific diversity
within the Anabaena isolates and indicated the potential as well as constraints of the morphological and protein profiling datasets for unambiguous
differentiation and analyses of diversity among the Anabaena strains. 相似文献
89.
Wei Zou Monica Croke Tomohiro Fukunaga Thomas J. Broekelmann Robert P. Mecham Steven L. Teitelbaum 《Journal of cellular biochemistry》2013,114(8):1871-1878
The αvβ3 integrin stimulates the resorptive capacity of the differentiated osteoclast (OC) by organizing its cytoskeleton via the tyrosine kinase, Syk. Thus, Syk‐deficient OCs fails to spread or form actin rings, in vitro and in vivo. The Syk family of tyrosine kinases consists of Syk itself and Zap70 which are expressed by different cell types. Because of their structural similarity, and its compensatory properties in other cells, we asked if Zap70 can substitute for absence of Syk in OCs. While expression of Syk, as expected, normalizes the cytoskeletal abnormalities of Syk?/? OCs, Zap70 fails do so. In keeping with this observation, Syk, but not Zap70, rescues αvβ3 integrin‐induced SLP76 phosphorylation in Syk?/? OCs. Furthermore the kinase sequence of Syk partially rescues the Syk?/? phenotype but full normalization also requires its SH2 domains. Surprisingly, expression of Zap70 inhibits WT OC spreading, actin ring formation and bone resorptive activity, but not differentiation. In keeping with arrested cytoskeletal organization, Zap70 blocks integrin‐activated endogenous Syk and Vav3, SLP76 phosphorylation. Such inhibition requires Zap70 kinase activity, as it is abolished by mutation of the Zap70 kinase domain. Thus, while the kinase domain of Syk is uniquely required for OC function that of Zap70 inhibits it. J. Cell. Biochem. 114: 1871–1878, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
90.
Shawn Thatcher April Leonard Marianna Lauer Gayathri Panangipalli Bret Norman Zhenglin Hou Victor Llaca Wang-Nan Hu Xiuli Qi Jennifer Jaqueth Dina Severns David Whitaker Bill Wilson Girma Tabor Bailin Li 《Molecular Plant Pathology》2023,24(7):758-767
Northern corn leaf blight, caused by the fungal pathogen Exserohilum turcicum, is a major disease of maize. The first major locus conferring resistance to E. turcicum race 0, Ht1, was identified over 50 years ago, but the underlying gene has remained unknown. We employed a map-based cloning strategy to identify the Ht1 causal gene, which was found to be a coiled-coil nucleotide-binding, leucine-rich repeat (NLR) gene, which we named PH4GP-Ht1. Transgenic testing confirmed that introducing the native PH4GP-Ht1 sequence to a susceptible maize variety resulted in resistance to E. turcicum race 0. A survey of the maize nested association mapping genomes revealed that susceptible Ht1 alleles had very low to no expression of the gene. Overexpression of the susceptible B73 allele, however, did not result in resistant plants, indicating that sequence variations may underlie the difference between resistant and susceptible phenotypes. Modelling of the PH4GP-Ht1 protein indicated that it has structural homology to the Arabidopsis NLR resistance gene ZAR1, and probably forms a similar homopentamer structure following activation. RNA sequencing data from an infection time course revealed that 1 week after inoculation there was a threefold reduction in fungal biomass in the PH4GP-Ht1 transgenic plants compared to wild-type plants. Furthermore, PH4GP-Ht1 transgenics had significantly more inoculation-responsive differentially expressed genes than wild-type plants, with enrichment seen in genes associated with both defence and photosynthesis. These results demonstrate that the NLR PH4GP-Ht1 is the causal gene underlying Ht1, which represents a different mode of action compared to the previously reported wall-associated kinase northern corn leaf blight resistance gene Htn1/Ht2/Ht3. 相似文献