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161.
Xi-Shu Gu Wen-Jun Bu Wei-Hong Xu Yi-Chuan Bai Bai-Ming Liu Tong-Xian Liu 《Insect Science》2008,15(3):263-270
We conducted three experiments for management of Bemisia tabaci (Gennadius) biotype ‘B’ on tomatoes under greenhouse conditions: (i) vertically placing yellow sticky cards either parallel or perpendicular to tomato rows at a rate of 1 per 3‐m row; (ii) releasing Eretmocerus sp. nr. rajasthanicus once at 30 adults/m2 in the high whitefly density greenhouses (> 10 adults/plant), or twice at 15 adults/m2 at a 5‐day interval in the low whitefly density greenhouses (< 10 adults/plant); and (iii) using combinations of yellow sticky cards that were placed vertically parallel to tomato rows and parasitoids released once at 30/m2 in high whitefly density greenhouses or twice at 15/m2 at a 5‐day interval in low whitefly density greenhouses. Our data show that yellow sticky cards trapped B. tabaci adults and significantly reduced whitefly populations on tomato. The yellow sticky cards that were placed parallel to tomato rows caught significantly more whitefly adults than those placed perpendicular to tomato rows on every sampling date. In the treatment where parasitoids were released once at 30/m2 in high whitefly density greenhouses, the number of live whitefly nymphs were reduced from 4.6/leaf to 2.9/leaf in 40 days as compared with those on untreated plants on which live whitefly nymphs increased from 4.4/leaf to 8.9/leaf. In the treatment where parasitoids were released twice at 15/m2 in low whitefly density greenhouses, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 2.1/leaf to 1.7/leaf in 20 days as compared with those on untreated plants on which numbers of live nymphs of B. tabaci increased from 2.2/leaf to 4.5/leaf. In the treatment of yellow sticky cards and parasitoid release once at 30/m2 in high whitefly density greenhouses, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 7.2/leaf to 1.9/leaf, and in the treatment of yellow sticky cards and parasitoid release twice at 15/m2 at a 5‐day interval at low whitefly density, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 2.5/leaf to 0.8/leaf; whereas the numbers of live nymphs of B. tabaci on untreated plants increased from 4.4/leaf to 8.9/leaf. An integrated program for management of B. tabaci on greenhouse vegetables by using yellow sticky cards, parasitoids and biorational insecticides is discussed. 相似文献
162.
Haiyan Bu Qingji Ren Xiuli Xu Kun Liu Peng Jia Shujun Wen Dashuai Sun Guozhen Du 《Frontiers of Biology in China》2008,3(2):187-193
The germination experiment was started on March 3, 2004, and seeds were collected from July to October in 2003. We analyzed
the percentage of germination, days to first germination, germination period and days to 50% germination. Among the 54 examined
species, 26 species exceeded 80% germination, 11 species exceeded 60%–80% germination, 8 exceeded 40%–0%, 5 exceeded 20%–40%,
and 4 showed less than 20%. A principal-component analysis revealed that the species were distributed along two statistically
independent axes, the first primarily represented the germination rate and the second represented the time of germination
process. Based on scores of germination characteristics, cluster analysis of the 54 gramineous species could be divided into
4 distinct groups: rapid, slow, intermediate germinating (germination percentage > 50%), and low germinating (germination
percentage < 50%). The meaning of different groups to the vegetation regeneration was discussed.
__________
Translated from Journal of Plant Ecology, 2006, 30(4): 624–632 [译自: 植物生态学报] 相似文献
163.
Shen WH Chen Z Shi S Chen H Zhu W Penner A Bu G Li W Boyle DW Rubart M Field LJ Abraham R Liechty EA Shou W 《The Journal of biological chemistry》2008,283(20):13842-13849
Mammalian target of rapamycin (mTOR) is a key regulator for cell growth through modulating components of the translation machinery. Previously, numerous pharmacological studies using rapamycin suggested that mTOR has an important role in regulating cardiac hypertrophic growth. To further investigate this assumption, we have generated two lines of cardiac specific mTOR transgenic mice, kinase-dead (kd) mTOR and constitutively active (ca) mTOR, using alpha-myosin heavy chain promoter. alpha-Myosin heavy chain (alphaMHC)-mTORkd mice had a near complete inhibition of p70 S6k and 4E-BP1 phosphorylation, whereas alphaMHC-mTORca had a significant increase in p70 S6k and 4E-BP1 phosphorylation. Although the cardiac function of alphaMHC-mTORkd mice was significantly altered, the cardiac morphology of these transgenic mice was normal. The cardiac hypertrophic growth in response to physiological and pathological stimuli was not different in alphaMHC-mTORkd and alphaMHC-mTORca transgenic mice when compared with that of nontransgenic littermates. These findings suggest that the mTOR-mediated signaling pathway is not essential to cardiac hypertrophic growth but is involved in regulating cardiac function. Additional analysis of cardiac responses to fasting-refeeding or acute insulin administration indicated that alphaMHC-mTORkd mice had a largely impaired physiological response to nutrient energy supply and insulin stimulation. 相似文献
164.
Leu BM Zhang Y Bu L Straub JE Zhao J Sturhahn W Alp EE Sage JT 《Biophysical journal》2008,95(12):5874-5889
Conformational flexibility is essential to the functional behavior of proteins. We use an effective force constant introduced by Zaccai, the resilience, to quantify this flexibility. Site-selective experimental and computational methods allow us to determine the resilience of heme protein active sites. The vibrational density of states of the heme Fe determined using nuclear resonance vibrational spectroscopy provides a direct experimental measure of the resilience of the Fe environment, which we compare quantitatively with values derived from the temperature dependence of atomic mean-squared displacements in molecular dynamics simulations. Vibrational normal modes in the THz frequency range dominate the resilience. Both experimental and computational methods find a higher resilience for cytochrome c than for myoglobin, which we attribute to the increased number of covalent links to the peptide in the former protein. For myoglobin, the resilience of the iron environment is larger than the average resilience previously determined for hydrogen sites using neutron scattering. Experimental results suggest a slightly reduced resilience for cytochrome c upon oxidation, although the change is smaller than reported in previous Mössbauer investigations on a bacterial cytochrome c, and is not reproduced by the simulations. Oxidation state also has no significant influence on the compressibility calculated for cyt c, although a slightly larger compressibility is predicted for myoglobin. 相似文献
165.
We described a novel approach to directly amplify genomic DNA from whole blood and dried blood spotted on filter paper without any DNA isolation by using the PCR buffer with a higher pH, which was optimized as pH 9.1-9.6. Direct PCR on blood treated with various anticoagulants showed that the buffer worked well with the blood treated by citrate, EDTA, or heparinate. DNA fragments with different lengths could be efficiently amplified directly from various forms of blood samples. By coupling the buffer with tetra-PCR, a "true" single-tube genotyping was realized by using whole blood or paper-dried blood as starting material. 相似文献
166.
167.
168.
Boon-Seng Wong David R. Brown † Tao Pan Matthew Whiteman ‡ Tong Liu Xiaodong Bu § Ruliang Li Pierluigi Gambetti John Olesik § Richard Rubenstein¶ Man-Sun Sy 《Journal of neurochemistry》2001,79(3):689-698
Prion diseases are characterized by the conversion of the normal cellular prion protein (PrP(C)) into a pathogenic isoform (PrP(Sc)). PrP(C) binds copper, has superoxide dismutase (SOD)-like activity in vitro, and its expression aids in the cellular response to oxidative stress. However, the interplay between PrPs (PrP(C), PrP(Sc) and possibly other abnormal species), copper, anti-oxidation activity and pathogenesis of prion diseases remain unclear. In this study, we reported dramatic depression of SOD-like activity by the affinity-purified PrPs from scrapie-infected brains, and together with significant reduction of Cu/Zn-SOD activity, correlates with significant perturbations in the divalent metals contents. We also detected elevated levels of nitric oxide and superoxide in the infected brains, which could be escalating the oxidative modification of cellular proteins, reducing gluathione peroxidase activity and increasing the levels of lipid peroxidation markers. Taken together, our results suggest that brain metal imbalances, especially copper, in scrapie infection is likely to affect the anti-oxidation functions of PrP and SODs, which, together with other cellular dysfunctions, predispose the brains to oxidative impairment and eventual degeneration. To our knowledge, this is the first study documenting a physiological connection between brain metals imbalances, the anti-oxidation function of PrP, and aberrations in the cellular responses to oxidative stress, in scrapie infection. 相似文献
169.
The regenerated shoot segments of Alhagi pseudalhagi were sliced and infected with Agrobacterium rhizogenes strain A4. The hairy roots and transformed calli were obtained through selection on hormone free MS medium. The transformants were cultured on MS medium with 2 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5-1 mg/L 6-benzylaminopurine (6-BA) to induce calli. 3 mg/L 6-BA and 0.5 mg/L naphthalene acetic acid (NAA) were applied for shoot differentiation. Shoots were planted on MS medium with 2 mg/L indole-3-butyric acid (IBA) and produced roots. Opine analysis proved the integration and expression of T-DNA in over 95% hairy roots, 75% transformed calli and transformed plantlets respectively. The 81% hairy root cells had normal chromosome numbers (2n = 18). The alterations of chromosome number were observed. After one year of subculturing, the regeneration ability of transformants was maintained. 相似文献
170.
Akiko Nishiyama Masahiko Watanabe Zhongshu Yang Jie Bu 《Brain Cell Biology》2002,31(6-7):437 ppl=-455
Cells that express the NG2 proteoglycan (NG2+ cells) comprise a unique population of glial cells in the central nervous system. While there is no question that some NG2+ cells differentiate into oligodendrocytes during development, the persistence of numerous NG2+ cells in the mature CNS has raised questions about their identity, relation to other CNS cell types, and functions besides their progenitor role. NG2+ cells also express the alpha receptor for platelet-derived growth factor (PDGF αR), a receptor that mediates oligodendrocyte progenitor proliferation during development. Antigenically, NG2+ cells are distinct from fibrous and protoplasmic astrocytes, resting microglia, and mature oligodendrocytes. Therefore, we propose the term polydendrocytesto refer to all NG2-expressing glial cells in the CNS parenchyma. This distinguishes them from the classical glial cell types and identifies them as the fourth major glial population in the CNS. Recent observations suggest that polydendrocytes are complex cells that physically and functionally interact with other cell types in the CNS. Committed oligodendrocyte progenitor cells arise from restricted foci in the ventral ventricular zone in both spinal cord and brain. It remains to be clarified whether there are multiple sources of oligodendrocytes, and if so whether polydendrocytes (NG2+ cells) represent progenitor cells of all oligodendrocyte lineages. Proliferation of NG2+ cells during early development appears to be dependent on PDGF, but the regulatory mechanisms that govern NG2+ cell proliferation in the mature CNS remain unknown. Pulse-chase labeling with bromodeoxyuridine indicates that polydendrocytes that proliferate in the postnatal spinal cord differentiate into oligodendrocytes. Novel experimental approaches are being developed to further elucidate the functional properties and differentiation potential of polydendrocytes. 相似文献