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41.
Anamika Sharma Ramandeep K. Sandhi Shabeg S. Briar John H. Miller Gadi V. P. Reddy 《Journal of Applied Entomology》2019,143(4):460-469
Wireworms, the larvae of click beetles (Elateridae), are difficult to manage due to their habitats and behaviour. Wireworms pose a major threat to the wheat crop in the north‐western USA. Seed treatment with neonicotinoids, biological control management and some cultural controls are recommended to manage these pests. Trap cropping is an emerging way to manage wireworms. In strawberry and potato crops, trap cropping has been found effective at attracting wireworms away from the principal crop. An earlier study in the Golden Triangle area of Montana found that pea and lentil could be effective trap crops for managing wireworms in spring wheat. In the present study, experiments were conducted at two locations. The effectiveness of peas and lentils as trap crops with wheat at different seeding densities was assessed [pea at 0, 4, 8, 16 seeds/sq.ft. or 0, 43, 86, 172 seeds/sq.m.; lentil at 0, 6, 12, 18 OR 0, 65, 130, 194 seeds/sq.m.; both with wheat at 0, 11, 22, or 28 seeds/sq.ft. or 0, 120, 230, 300 seeds/sq.m.] in a randomized design where all three crops were intercropped. Both trap crops were found to be effective in protecting wheat at standard seeding rates of 8 seeds/sq.ft. for pea and 12 seeds/sq.ft. for lentils. At these seeding rates, higher numbers of wireworms were found to be attracted to the trap crop, resulting in higher yield (7%–10%) of the associated spring wheat plant stands at 22 seeds/sq.ft. To develop an effective trap crop strategy, the pea–wheat and lentil–wheat spatial patterns that are possible need to be assessed in further field trials. Proper design and evaluation of the cost–benefit ratio of pea and lentil as trap crops are likely to produce good results for wheat crops in Montana. 相似文献
42.
Yixing Wang Ajay K. Jha Rujin Chen John H. Doonan Ming Yang 《Genesis (New York, N.Y. : 2000)》2010,48(4):254-263
Formation of polyploid organisms by fertilization of unreduced gametes in meiotic mutants is believed to be a common phenomenon in species evolution. However, not well understood is how species in nature generally exist as haploid and diploid organisms in a long evolutionary time while polyploidization must have repeatedly occurred via meiotic mutations. Here, we show that the ploidy increased for two consecutive generations due to unreduced but viable gametes in the Arabidopsis cyclin a1;2‐2 (also named tardy asynchronous meiosis‐2) mutant, but the resultant octaploid plants produced progeny of either the same or reduced ploidy via genomic reductions during meiosis and pollen mitosis. Ploidy reductions through sexual reproduction were also observed in independently generated artificial octaploid and hexaploid Arabidopsis plants. These results demonstrate that octaploid is likely the maximal ploidy produced through sexual reproduction in Arabidopsis. The polyploidy‐associated genomic instability may be a general phenomenon that constrains ploidy levels in species evolution. genesis 48:254–263, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
43.
Gold containing Ayurvedic preparation, Swarna Vasant Malti, was given to 20 male persons in a dose of 100 mg twice a day for 40 days under supervision of Ayurvedic physicians. The total cumulative intake of 160 mg of gold at the rate of 4 mg per day in this form did not have any toxic effect on human body as evidenced by clinical examination, unaltered body weight, absence of urinary pathology and by 30 sensitive biochemical and enzymatic tests. The gold from this Ayurvedic preparation was found in plasma and erythrocytes, excreted partly in urine and was present in semen. Gold binding to albumin and hemoglobin slightly increased their electrophoretic mobility towards anode. This gold preparation seemed to increase sperm motility and prostatic activity. 相似文献
44.
The root: a potential new source of competent cells for high-frequency regeneration in Tylophora indica 总被引:3,自引:0,他引:3
The purpose of this study was to develop a new micropropagation system for Tylophora indica, an important medicinal plant in India, using root explants as starting material. Root explants cultured on MS medium supplemented with 6-benzyladenine (BA) or 2-isopentyladenine (2iP) produced organogenic nodular meristemoids (NMs) within 4 weeks. NMs induced from the cut ends of root segments showed two types of organogenic response—direct shoot bud formation and somatic embryogenesis—when maintained on induction medium. In 42% of the explants, NMs developed shoot buds directly in the presence of 10.72–26.80 M BA. On average, 18.5±0.7 shoots per gram of NM tissue were obtained after each 4-week subculture. Elongation of microshoots and root initiation were correlated with the auxin used, with the optimal response occurring in the presence of 28.54 M indole-3-acetic acid. In 39% of the explants, NMs dedifferentiated into friable embryogenic callus (FEC) in the presence of BA or 2iP after 12 weeks of culture. Of the different treatments, MS medium supplemented with 10.72 M BA was the most effective in inducing FEC and somatic embryogenesis: at this concentration 64% of the cultured NMs developed FEC and, on the same medium, 89% of the FEC produced globular somatic embryos (SEs). FEC biomass increased nearly five-fold with every 4-week subculture, and about 30 SEs were recovered per gram of FEC during this period. The best conversion of mature SEs to complete plantlets was obtained on basal MS medium–42%. Plantlets derived via somatic embryogenesis and shoot organogenesis were successfully hardened (88–96%) and transferred to the field.Abbreviations BA: 6-Benzyladenine - 2,4-D: 2,4-Dichlorophenoxyacetic acid - FEC: Friable embryogenic callus - GRS: Green root segment - IAA: Indole-3-acetic acid - IBA: Indole-3-butyric acid - 2ip: 2-Isopentyladenine - Kin: Kinetin - NAA: -Naphthaleneacetic acid - NM: Nodular meristemoid - SE: Somatic embryo - WRS: White root segmentCommunicated by P. Lakshmanan 相似文献
45.
Inactivation of Cyanobacterial Nitrogenase After Exposure to Ultraviolet-B Radiation 总被引:2,自引:0,他引:2
Exposure of the N2-fixing cyanobacterium Anabaena BT2 to ultraviolet-B radiation (2.5 W m−2) for 30 min resulted in complete loss of nitrogenase activity but 100% cell killing occurred only after a 90-min exposure.
Inactivation of nitrogenase activity was not specific to Anabaena BT2; other species also showed a similar effect. The time required for 100% killing and inactivation of nitrogenase activity
differed in various species, and this difference may be ascribed to the presence of different levels of UV-B protection mechanisms
in individual species. Inhibition of nitrogenase activity was immediate, since exposure of cultures to UV-B for as little
as 5 min elicited some inhibition of activity. The activity of UV-B-inhibited nitrogenase did not recover upon transfer of
exposed cells to fluorescent light, suggesting that the inhibition may be due to specific inactivation of the enzyme. By employment
of inhibitors of protein synthesis and PS-II activity, it was demonstrated that restoration of nitrogenase activity in a UV-B-treated
culture occurred by fresh synthesis of nitrogenase polypeptide. Our findings suggest that estimation of nitrogenase activity
in diazotrophic species may be used as a marker enzyme for assessing the impact of UV-B radiation.
Received: 13 June 2002 / Accepted: 22 July 2002 相似文献
46.
Debnath B Gayen S Bhattacharya S Samanta S Jha T 《Bioorganic & medicinal chemistry》2003,11(24):5493-5499
Pyridoacridine ascididemin analogues have been reported as anticancer agents for their interesting antitumor activity against human cancer cells. A quantitative structure–activity relationship (QSAR) analysis of ascididemin analogues was attempted using the physicochemical parameters and the electrotopological state atom (ETSA) indices. This study indicates that the electron withdrawing substituents with higher MR (molar refractivity) value at R1 position favor the anti-tumor activity and the presence of NHR (R is hydrogen or alkyl group) at the R3 position has contribution to the anti-tumor activity. ETSA indices have been incorporated as independent variable in the QSAR model with physicochemical parameters. It clearly suggests the importance of atoms 2, 3, 4, 5, 6 and 7 to the anti-tumor activity. 相似文献
47.
Covalent modification of cysteine 193 impairs ATPase function of nucleotide-binding domain of a Candida drug efflux pump 总被引:3,自引:0,他引:3
Jha S Karnani N Lynn AM Prasad R 《Biochemical and biophysical research communications》2003,310(3):869-875
N-ethylmaleimide (NEM) impairs the ATPase function of N-terminal NBD of Candida drug resistance gene product Cdr1p. To identify the reactive cysteine(s) for such a contribution, we adopted a three-arm approach that included covalent modification, cysteine mutagenesis, and structure homology modeling. The covalent modification results clearly indicate the ability of NEM and iodoacetic acid (IAA) to potently inhibit the ATPase activity of N-terminal NBD. Since this domain contains five cysteine residues in its sequence, we mutated each and found four of these (C325A, C363A, C402A, and C462A) to stay sensitive to NEM/IAA modification and influence ATPase activity, while C193A mutation completely abrogated the catalytic function. The structural homology modeling data further validate these biochemical findings by ruling out any plausible interactions within the cysteine residues, and deriving the importance of Cys-193 in lying at a bond length clearly feasible to interact with ATP and divalent cation to critically influence ATP hydrolysis. 相似文献
48.
Two plant alkaloids isolated from<Emphasis Type="Italic">Corydalis longipes</Emphasis> as potential antifungal agents 总被引:1,自引:0,他引:1
The alkaloids N-methylhydrasteine hydroxylactam and 1-methoxyberberine chloride were isolated from Corydalis longipes. Both alkaloids showed high efficacy individually (in concentration of 50-150 ppm) and also in a 1:1 mixture against spore germination of some fungi, viz. Alternaria alternata, A. brassicae, Curvularia maculans, Curvularia sp., Colletotrichum gloeosporioides, Colletotrichum sp., Helminthosporium speciferum, H. pennisetti, Helminthosporium sp., and Ustilago cynodontis. The antifungal effect of single compounds was dose-dependent. If the mutual ratio of the two components in the mixture was changed from 1:1 to a major content of any of the two compounds, the inhibitory effect on spore germination decreased. 相似文献
49.
Formoguanamine (2,4-diamino-s-triazine) was known to be an effective chemical agent in inducing blindness in poultry chicks,
but not in adult birds. The present study was undertaken to demonstrate the influences, if any, of this chemical on the visual
performance and retinal histology in an adult sub-tropical wild bird, the roseringed parakeet (Psittacula krameri). Formoguanamine (FG) hydrochloride was subcutaneously injected into adult parakeets at a dosage of 25 mg (dissolved in 0.75
ml physiological saline)/100 g body weight/day, for two consecutive days while the control birds were injected only with a
placebo. The effects were studied after 10, 20 and 30 days of the last treatment of FG. Within 24 h of the treatment of FG,
about 90% of the total birds exhibited lack of visual responses to any light stimulus and even absence of pupillary light
reactions. The remaining birds became totally blind on the day following the last injection of FG and remained so till the
end of investigation. At the microscopic level, conspicuous degenerative changes were noted in the outer pigmented epithelium
and the photoreceptive layer of rods and cones in the retinas of FG treated birds. A significant reduction in the thickness
of the outer nuclear layer was also found in the retinas of FG treated parakeets, compared to that in the control birds. However,
the inner cell layers of the retina in the control and FG administered parakeets were almost identical. It deserves special
mention that the effects of FG, noted after 30 days of last treatment, were not very different from those noted just after
10 days of treatment. Collectively, the results of the present investigation demonstrate that FG can be used as a potent pharmacological
agent for inducing irreversible blindness through selective damage in retinal tissue even in the adult wild bird, thereby
making FG treatment an alternative euthanasic device to a cumbersome, stressful, surgical method of enucleation of the ocular
system for laboratory studies. 相似文献
50.
Endostatin is a potential inhibitor of Wnt signaling 总被引:33,自引:0,他引:33
Hanai J Gloy J Karumanchi SA Kale S Tang J Hu G Chan B Ramchandran R Jha V Sukhatme VP Sokol S 《The Journal of cell biology》2002,158(3):529-539