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61.
Social insects live in colonies consisting of many workers, where worker interactions play an important role in regulating colony activities. Workers interact within the social space of the nest; therefore, constraints on nest space may alter worker behaviour and affect colony activities and energetics. Here we show in the ant Temnothorax rugatulus that changes in nest space have a significant effect on colony energetics. Colonies with restricted nest space showed a 14.2 per cent increase in metabolic rate when compared with the same colonies in large uncrowded nests. Our study highlights the importance of social space and shows that constraints on social space can significantly affect colony behaviour and energy use in ants. We discuss the implications of our findings regarding social insects in general. 相似文献
62.
We present here microwave-based modifications of standard protein assays that dramatically reduce the time required to determine
protein concentrations. Typical protein determinations involve incubation times ranging from 15–60 min. Microwave irradiation
of specimens reduces this time requirement to 10–20 s without compromising accuracy or reliability. The remarkable speed with
which protein determinations may be carried out using microwave enhancement greatly simplifies general laboratory procedures
that depend on the estimation of protein concentrations.
An erratum to this article is available at . 相似文献
63.
Bui Hai Ninh Duong Thi Dung Bui Huu Tai Pham Hai Yen Nguyen Xuan Nhiem Truong Thi Thu Hien Do Thi Trang Nguyen Van Tuyen Le Tuan Anh Nguyen Thi Hoai Phan Van Kiem 《化学与生物多样性》2023,20(3):e202201048
A new isopropyl chromone ( 1 ) and a new flavanone glucoside ( 2 ) together with eleven known compounds ( 3–13 ) were isolated from the leaves of Syzygium cerasiforme (Blume) Merr. & L.M.Perry. Their structures were elucidated as 5,7-dihydroxy-2-isopropyl-6,8-dimethyl-4H-chromen-4-one ( 1 ), 5,7-dihydroxyflavanone 7-O-β-D-(6′′-O-galloylglucopyranoside) ( 2 ), strobopinin ( 3 ), demethoxymatteucinol ( 4 ), pinocembrin-7-O-β-D-glucopyranoside ( 5 ), (2S)-hydroxynaringenin-7-O-β-D-glucopyranoside ( 6 ), afzelin ( 7 ), quercetin ( 8 ), kaplanin ( 9 ), endoperoxide G3 ( 10 ), grasshopper ( 11 ), vomifoliol ( 12 ), litseagermacrane ( 13 ) by the analysis of HR-ESI-MS, NMR, and CD spectral data. Compounds 1 , 2 , 5 , 6 and 10 inhibited NO production on LPS-activated RAW264.7 cells with IC50 values of 12.28±1.15, 8.52±1.62, 7.68±0.87, 9.67±0.57, and 6.69±0.34 μM, respectively, while the IC50 values of the other compounds ranging from 33.38±0.78 to 86.51±2.98 μM, compared to that of the positive control, NG-monomethyl-L-arginine acetate (L-NMMA) with an IC50 value of 32.50±1.00 μM. 相似文献
64.
65.
Rocky S. Tuan 《Developmental biology》1980,74(1):196-204
In order to investigate the influence of the egg shell on the process of shell calcium mobilization by the chorioallantoic membrane (CAM), chick embryos were maintained in long-term cultures in vitro without the shells. The shell-less embryos were severely calcium deficient and showed signs of retarded development and anomalous skeletal calcification. Throughout development, calcium transport and calcium-binding protein (CaBP) activities were diminished in the CAM of shell-less embryos as compared to those of control embryos which developed in ovo. The levels of developmentally expressed carbonic anhydrase activity remained, however, similar. By means of a single radial immunodiffusion assay of CaBP using a specific anti-CaBP antiserum, the level of immunoreactive CaBP was found to be significantly increased in the CAM of the shell-less embryos. These studies indicate that the CAM of chick embryos cultured under shell-less conditions is defective in calcium transport, probably as a result of the expression of an inactive form of the CaBP. 相似文献
66.
Phan Tu Quy Nguyen Khoa Hien Nguyen Chi Bao Doan Thanh Nhan Dang Van Khanh Nguyen Thi Ai Nhung Truong Quy Tung Nguyen Dinh Luyen Duong Tuan Quang 《Luminescence》2015,30(3):325-329
A new rhodamine–ethylenediamine–nitrothiourea conjugate (RT) was synthesized and its sensing property as a fluorescent chemodosimeter toward metal ions was explored in water media. Analytical results from absorption and fluorescence spectra revealed that the addition of Hg2+ ions to the aqueous solution of the chemodosimeter RT caused a distinct fluorescence OFF–ON response with a remarkable visual color change from colorless to pink; however, no clear spectral and color changes were observed from other metal ions including: Zn2+, Cu2+, Cd2+, Pb2+, Ag+, Fe2+, Cr3+, Co3+, Ni2+, Ca2+, Mg2+, K+ and Na+. The sensing results and the molecular structure suggested that a Hg2+‐induced a desulfurization reaction and cyclic guanylation of the thiourea moiety followed by ring‐opening of the rhodamine spirolactam in RT are responsible for a distinct fluorescence turn‐on signal, indicating that RT is a remarkably sensitive and selective chemodosimeter for Hg2+ ions in aqueous solution. Hg2+ within a concentration range from 0.1 to 25 μM can be determined using RT as a chemodosimeter and a detection limit of 0.04 μM is achieved. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
67.
Efficient chondrogenic differentiation of mesenchymal cells in micromass culture by retroviral gene transfer of BMP-2 总被引:11,自引:0,他引:11
A.L. Carlberg · B. Pucci · R. Rallapalli · R.S. Tuan · D.J. Hall 《Differentiation; research in biological diversity》2001,67(4-5):128-138
The multipotential murine embryonic C3H10T1/2 mesenchymal cell line is able to undergo chondrogenesis in vitro, in a high density micromass environment, following treatment with soluble human bone morphogenetic protein-2 (BMP-2). To enhance this process, the human BMP-2 cDNA was cloned into a retroviral expression vector and a high titer, infectious retrovirus (replication defective) was generated. Infection of C3HIOT1/2 cells with this retroviral construct resulted in an infection efficiency of 90-95% and was highly effective in converting cells in micromass culture to a chondrocyte phenotype, as assessed by positive Alcian blue staining for extracellular matrix proteoglycans, increased sulfate incorporation, increased expression of the cartilage marker genes collagen type II and aggrecan, and decreased expression of collagen type I. Interestingly, BMP-2 expression in the micromass cultures also induced the expression of the cell cycle inhibitory protein/differentiation factor p21/WAF1, suggesting its functional involvement in chondrogenesis. The chondrogenic effect of retrovirally expressed BMP-2 in these high-density cultures was limited to the infected cells, since uninfected cells did not chondrify when co-cultured as a nonoverlapping micromass adjacent to BMP-2 expressing cells. These data indicate that retrovirally expressed BMP-2 is highly effective at inducing a chondrocyte phenotype in a multipotential mesenchymal cell line in vitro, and its action is restricted to the infected cell population. These findings should provide a framework for the optimization of chondrogenesis in culture using mesenchymal stem cells and retroviral gene transfer. 相似文献
68.
Analysis of Vibrio seventh pandemic island II and novel genomic islands in relation to attachment sequences among a wide variety of Vibrio cholerae strains 下载免费PDF全文
Tuan Hai Nguyen Tho Duc Pham Naomi Higa Hanako Iwashita Taichiro Takemura Makoto Ohnishi Kouichi Morita Tetsu Yamashiro 《Microbiology and immunology》2018,62(3):150-157
69.
Hiroaki Harayama Masafumi Koide Koji Obata Akio Iio Masato Iida Nahomi Matsuda Robert E. Akins Mitsuhiro Yokota Rocky S. Tuan Hidehiko Saito 《Journal of cellular physiology》1998,177(2):289-298
An accelerated weight gain is noted in the heart of Ca-deficient, hypertensive chick embryos maintained in a shell-less culture in vitro. We previously observed that the Ca handling property of cardiomyocytes isolated from the shell-less embryo is altered, i.e., faster Ca uptake, suggesting a requirement for adequate Ca supply and/or proper Ca handling in embryonic cardiac development. In this study, we have examined the function of Ca on cardiomyocytes by analyzing the effects of (1) various Ca concentration in the culture medium (NCa, 1.8 mmol/L; HCa, 2.8 mmol/L; LCa, 0.9 mmol/L), and (2) various modulators of Ca handling on cell proliferation and phenotype regulation in chick embryonic cardiomyocytes. The analytical parameters included cell number, DNA content, expression of cell cycle–specific and cardiomyocyte-specific proteins, and creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) enzyme activities. Cell number and total DNA were significantly larger (P < 0.01) in LCa cultures compared with those in NCa. The level of LDH was elevated (P < 0.01), but that of CPK was lowered in LCa. Expression of the G1-S–specific protein PCNA was raised, but that of the contractile proteins myosin and tropomyosin was substantially suppressed in LCa; in HCa, the cells did not proliferate as well, whereas the level of contractile proteins was higher. Thapsigargin, a sarcoplasmic reticulum (SR)-specific, Ca-ATPase inhibitor, simulated the effects of LCa by enhancing cell proliferation and lowering the expression of tropomyosin. These results suggest that culturing in low Ca concentration and inhibition of SR Ca pumping enhance myocardial cell proliferation and suppress sarcomeric protein expression, perhaps by inducing cellular de-differentiation. The in vitro effects of medium Ca concentration and Ca handling modulators on cardiomyocytes also suggest that the in vivo cardiomegaly of the SL embryos is a direct result of Ca-deficiency, and that Ca is important in the phenotype regulation of cardiomyocytes. J. Cell. Physiol. 177:289–298, 1998. © 1998 Wiley-Liss, Inc. 相似文献
70.
Host plants mixture and fitness of Kolla paulula: with an evaluation of the application of Weibull function 下载免费PDF全文
S.‐J. Tuan P.‐W. Chang P. Saska R. Atlihan H. Chi 《Journal of Applied Entomology》2017,141(5):329-338
The xylem‐feeding leafhopper Kolla paulula (Walker), a vector of Pierce's disease, occurs primarily on weeds in and around fruit and ornamental crop orchards in Taiwan. Because our preliminary studies showed that K. paulula performed poorly when reared on pilose beggarticks (Bidens pilosa L. var. radiata) (PB) or trilobate wedelia (Wedelia triloba (L.)) (TW) alone, we collected the life table data of K. paulula reared on a mixture of both host plants to determine the effect at the population level. During their lifespan, 95.6% of feeding time was spent on the major host plant (PB) and only 4.4% on the minor host plant (TW). The intrinsic rate of increase (r), finite rate of increase (λ), net reproduction rate (R0) and mean generation time (T) of K. paulula were 0.0487, 1.0500 day?1, 35.86 offspring and 73.4 days, respectively. Because more than 95% of the insects have been observed feeding on both plants, this would indicate that the minor host plant may play an important role in the fitness of K. paulula regardless of the short feeding time. We calculated the percentage contribution to the population parameters made by females that had fed on both PB and TW and compared these with the values obtained for offspring of females that had fed solely on PB. We also evaluated the usefulness of applying the Weibull distribution in demographic studies. We demonstrated that when there is a higher mortality in specific life stages, the fitted Weibull distribution would be inaccurate in describing the survival curve and that application of the fitted curve to the calculation of life expectancy or other statistics would result in significant discrepancy to the actual curve. 相似文献