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51.
Field studies were conducted during 1999-2001 in two climatic/edaphic areas of Georgia (Southern Piedmont and East Gulf Coastal Plain) to test the hypothesis that precision placement of aldicarb with cotton seed in hill planting at spatially specific intervals could decrease insecticide use for management of tobacco thrips, Frankliniella fusca (Hinds). Precision-placed aldicarb controlled thrips during cotton seedling stages using per ha amounts of one-half or less than standard in-furrow application rates with no significant differences in yield. Residual analysis of cotton plants showed that plants in precision placement plots had as much or more aldicarb and aldicarb metabolites present as compared with cotton treated with conventional in-furrow treatments. Higher rates of precision-placed aldicarb did cause phytotoxic burning early in the growing season, but no significant impact on yield was observed. 相似文献
52.
Combining cry1Ac with QTL alleles from PI 229358 to improve soybean resistance to lepidopteran pests
Walker David Roger Boerma H. All John Parrott Wayne 《Molecular breeding : new strategies in plant improvement》2002,9(1):43-51
A QTL conditioning corn earworm resistance in soybean PI 229358 and asynthetic Bacillus thuringiensis cry1Ac transgene from therecurrent parent Jack-Bt were pyramided intoBC2F3 plants by marker-assisted selection. Segregatingindividuals were genotyped at SSR markers linked to an anitbiosis/antixenosisQTL on linkage group M, and were tested for the presence ofcry1Ac. Marker-assisted selection was used during andafter the two backcrosses to develop a series of BC2F3plants with or without the crylAc transgene and the QTLconditioning for resistance BC2F3 plants that werehomozygous for parental alleles at markers on LG M, and whicheither had or lacked cry1Ac, were assigned to one of fourpossible genotype classes. These plants were used in no-choice, detached leaffeeding bioassays with corn earworm and soybean looper larvae (Lepidoptera:Noctuidae) to evaluate the relative antibiosis in the different genotypeclasses. Resistance was measured as larval weight gain and degree of foliageconsumption. Few larvae of either species survived on leaves expressing theCry1Ac protein. Though not as great as the effect of Cry1Ac, the PI229358-derived LG M QTL also had a detrimental effect on larval weights of bothpest species, and on defoliation by corn earworm, but did not reduce defoliation bysoybean looper. Weights of soybean looper larvae fed foliage from transgenicplants with the PI-derived QTL were lower than those of larvae fed transgenictissue with the corresponding Jack chromosomal segment. This work demonstratesthe usefulness of SSRs for marker-assisted selection in soybean, and shows thatcombining transgene-and QTL-mediated resistance to lepidopteran pests may be aviable strategy for insect control. 相似文献
53.
AIM: To investigate the factors governing the adhesion and activity of the 2,4,6-tribromophenol (TBP) degrading bacterium Achromobacter piechaudii TBPZ-N61 on chalk from a contaminated aquifer. METHODS AND RESULTS: Adhesion kinetics of TBPZ-N61 to grey and white chalk from a polluted fractured chalk aquifer was tested in a batch system. Both grey and white chalk contain ca 80% CaCO3, while grey chalk contains more organic matter (2.4%) than the white chalk (0.3%) and also contains Dolmite and Clinoptilolite. Adhesion of the bacterial cells to the chalk particles (<0.2 mm) occurred rapidly (96% of the cells within 15 min). Langmuir-fitted adhesion isotherms suggest that cells in the stationary phase, which are more hydrophobic, adhere to both grey and white chalk more efficiently than cells in the logarithmic growth phase. Increasing the pH (from 6.7 to 8.1) caused a significant reduction in cell adhesion to the chalk. Activity of attached cells was evaluated in both batch and column experiments. Logarithmic cells adhering to white and grey chalk were more active in TBP degradation than cells in suspension. In column experiments, significant TBP degradation was retained up to 30 days after a single injection of TBPZ cells. Thereafter, activity was fully recovered by amendment of yeast extract. Chalk surfaces that were incubated in situ in contaminated groundwater for 20 days still allowed the adhesion and activity of TBPZ cells. CONCLUSIONS: Taken together, our results show that bacteria adhere efficiently to specific sites on the chalk surfaces, and that sustained bacterial activity of the attached cells can be achieved by adding a carbon source such as yeast extract which also overcome toxic constituents that may occur in some chalk types. SIGNIFICANCE AND IMPACT OF THE STUDY: Bioremediation of TBP-contaminated chalk aquifers is made possible by the injection of bacterial cultures. 相似文献
54.
Walker DR All JN McPherson RM Boerma HR Parrott WA 《Journal of economic entomology》2000,93(3):613-622
A transgenic line of the soybean 'Jack', Glycine max (L.) Merrill, expressing a synthetic cry1Ac gene from Bacillus thuringiensis variety kurstaki (Jack-Bt), was evaluated for resistance to four lepidopteran pests in the field. Jack-Bt and genotypes serving as susceptible and resistant controls were planted in field cages and artificially infested with larvae of corn earworm, Helicoverpa zea (Boddie), and velvetbean caterpillar, Anticarsia gemmatalis (Hübner), in 1996, 1997, and 1998, and also with soybean looper, Pseudoplusia includens (Walker), in 1996. Susceptible controls included Jack (1996-1998), 'Cobb' (1996), and Jack-HPH (1996). GatIR 81-296 was used as the resistant control in all 3 yr. Compared with untransformed Jack, Jack-Bt showed three to five times less defoliation from corn earworm and eight to nine times less damage from velvetbean caterpillar. Defoliation of GatIR 81-296 was intermediate between that of Jack and Jack-Bt for corn earworm, and similar to that of Jack for velveltbean caterpillar. Jack-Bt exhibited significant, but lower resistance to soybean looper. Jack-Bt also showed four times greater resistance than Jack to natural infestations of lesser cornstalk borer, Elasmopalpus lignosellus (Zeller), in conventional field plots at two locations in 1998. Data from these experiments suggest that expression of this cry1Ac construct in soybean should provide adequate levels of resistance to several lepidopteran pests under field conditions. 相似文献
55.
Howayda Abd El All 《Diagnostic pathology》2007,2(1):1-8
Background
Fulminant hepatic failure (FHF) is rapidly fatal and liver transplant is the treatment of choice. The condition is known for its heterogeneity of defining criteria, clinical presentation, histologic spectrum and etiologic factors. The etiology of FHF varies widely, some of which includes viral hepatitis, drug overdose and idiosyncratic drug reactions. The identification of the etiology of FHF is critically important, because it influences the management. A histopathological classification of FHF has not been reported earlier in the literature.Methods
The current study was conducted retrospectively on 224 autopsies at a tertiary care hospital in India. In all of these cases the liver was examined grossly and microscopically. Clinical findings, serological data and immunohistochemical findings were correlated with the morphological subtypes and a consensus morphological classification was formulated.Results
Young females, especially those in the reproductive age group were most susceptible to the disease. Hepatotropic viruses and drugs were the likely causes in most of the patients. Clinical presentation is important, as delayed onset of encephalopathy or the subacute FHFs lead to maximum mortality. After careful gross and microscopic examination the morphological findings of FHF were divided into four distinct categories. Histologic typing can sometimes be misleading if solely made on H & E slides without application of special stains.Conclusion
Fulminant hepatic failure is a medical emergency, proper histological categorization can help in deciding the treatment modalities. 相似文献56.
Allègre M Daire X Héloir MC Trouvelot S Mercier L Adrian M Pugin A 《The New phytologist》2007,173(4):832-840
In grapevine, the penetration and sporulation of Plasmopara viticola occur via stomata, suggesting functional relationships between guard cells and the pathogen. This assumption was supported by our first observation that grapevine (Vitis vinifera cv. Marselan) cuttings infected by P. viticola wilted more rapidly than healthy ones when submitted to water starvation. Here, complementary approaches measuring stomatal conductance and infrared thermographic and microscopic observations were used to investigate stomatal opening/closure in response to infection. In infected leaves, stomata remained open in darkness and during water stress, leading to increased transpiration. This deregulation was restricted to the colonized area, was not systemic and occurred before the appearance of symptoms. Cytological observations indicated that stomatal lock-open was not related to mechanical forces resulting from the presence of the pathogen in the substomatal cavity. In contrast to healthy leaves, stomatal closure in excised infected leaves could not be induced by a water deficit or abscisic acid (ABA) treatment. However, ABA induced stomatal closure in epidermal peels from infected leaves, indicating that guard cells remained functional. These data indicate that the oomycete deregulates guard cell functioning, causing significant water losses. This effect could be attributed to a nonsystemic compound, produced by the oomycete or by the infected plant, which inhibits stomatal closure or induces stomatal opening; or a reduction of the back-pressure exerted by surrounding epidermal cells. Both hypotheses are under investigation. 相似文献
57.
Angelo H. All Payam Gharibani Siddharth Gupta Faith A. Bazley Nikta Pashai Bin-Kuan Chou Sandeep Shah Linda M. Resar Linzhao Cheng John D. Gearhart Candace L. Kerr 《PloS one》2015,10(1)
Induced pluripotent stem (iPS) cells are at the forefront of research in regenerative medicine and are envisaged as a source for personalized tissue repair and cell replacement therapy. Here, we demonstrate for the first time that oligodendrocyte progenitors (OPs) can be derived from iPS cells generated using either an episomal, non-integrating plasmid approach or standard integrating retroviruses that survive and differentiate into mature oligodendrocytes after early transplantation into the injured spinal cord. The efficiency of OP differentiation in all 3 lines tested ranged from 40% to 60% of total cells, comparable to those derived from human embryonic stem cells. iPS cell lines derived using episomal vectors or retroviruses generated a similar number of early neural progenitors and glial progenitors while the episomal plasmid-derived iPS line generated more OPs expressing late markers O1 and RIP. Moreover, we discovered that iPS-derived OPs (iPS-OPs) engrafted 24 hours following a moderate contusive spinal cord injury (SCI) in rats survived for approximately two months and that more than 70% of the transplanted cells differentiated into mature oligodendrocytes that expressed myelin associated proteins. Transplanted OPs resulted in a significant increase in the number of myelinated axons in animals that received a transplantation 24 h after injury. In addition, nearly a 5-fold reduction in cavity size and reduced glial scarring was seen in iPS-treated groups compared to the control group, which was injected with heat-killed iPS-OPs. Although further investigation is needed to understand the mechanisms involved, these results provide evidence that patient-specific, iPS-derived OPs can survive for three months and improve behavioral assessment (BBB) after acute transplantation into SCI. This is significant as determining the time in which stem cells are injected after SCI may influence their survival and differentiation capacity. 相似文献
58.
Maryam Diarra Moussa Fall Renaud Lancelot Aliou Diop Assane G. Fall Ahmadou Dicko Momar Talla Seck Claire Garros Xavier Allène Ignace Rakotoarivony Mame Thierno Bakhoum Jérémy Bouyer Hélène Guis 《PloS one》2015,10(6)
In Senegal, considerable mortality in the equine population and hence major economic losses were caused by the African horse sickness (AHS) epizootic in 2007. Culicoides oxystoma and Culicoides imicola, known or suspected of being vectors of bluetongue and AHS viruses are two predominant species in the vicinity of horses and are present all year-round in Niayes area, Senegal. The aim of this study was to better understand the environmental and climatic drivers of the dynamics of these two species. Culicoides collections were obtained using OVI (Onderstepoort Veterinary Institute) light traps at each of the 5 sites for three nights of consecutive collection per month over one year. Cross Correlation Map analysis was performed to determine the time-lags for which environmental variables and abundance data were the most correlated. C. oxystoma and C. imicola count data were highly variable and overdispersed. Despite modelling large Culicoides counts (over 220,000 Culicoides captured in 354 night-traps), using on-site climate measures, overdispersion persisted in Poisson, negative binomial, Poisson regression mixed-effect with random effect at the site of capture models. The only model able to take into account overdispersion was the Poisson regression mixed-effect model with nested random effects at the site and date of capture levels. According to this model, meteorological variables that contribute to explaining the dynamics of C. oxystoma and C. imicola abundances were: mean temperature and relative humidity of the capture day, mean humidity between 21 and 19 days prior a capture event, density of ruminants, percentage cover of water bodies within a 2 km radius and interaction between temperature and humidity for C. oxystoma; mean rainfall and NDVI of the capture day and percentage cover of water bodies for C. imicola. Other variables such as soil moisture, wind speed, degree days, land cover or landscape metrics could be tested to improve the models. Further work should also assess whether other trapping methods such as host-baited traps help reduce overdispersion. 相似文献
59.
All��via Rouse Ferreira dos Santos Ana M. Ramos-Cabrer M Belen D��az-Hern��ndez Santiago Pereira-Lorenzo 《Tree Genetics & Genomes》2011,7(5):1041-1056
This is the first known large-scale molecular study of simple sequence repeats loci based on pear cultivars from the northwestern
Iberian Peninsula. Most of the Spanish pear crop (one of the largest in Europe) is based on the Spanish cultivar Blanquilla
and various other foreign cultivars. However, local cultivars can still be found in old orchards in northwestern Spain. Between
1978 and 1981, the Centro de Investigaciones Agrarias de Mabegondo (Xunta de Galicia) established a Germplasm Bank of local
pear cultivars containing 221 accessions. In the current study, these were analysed and compared with 20 commercial cultivars
of Pyrus spp. using 19 microsatellites. We identified 127 genotypes out of 221 accessions with an average of 43% clonality in this
collection. Genotypes were analysed using a model-based Bayesian procedure (Structure), factorial correspondence analysis
and molecular variance analysis, and Jaccard coefficients were estimated. Four reconstructed populations were identified by
Structure, one related to Asian cultivars, two to French and English cultivars and one to Galician cultivars. The four identified
groups of pears had evolved independently. This study explains the diversification process in pear cultivars from northwestern
cultivars based on hybridization (16%), selection of triploids (38%) and the introgression of commercial cultivars in the
collection (4%). 相似文献
60.
P. K. Roy K. All Anju Gupta G. K. Barat S. L. Mehta 《Journal of plant biochemistry and biotechnology.》1993,2(1):9-13
Protocols have been developed for in vitro regeneration from internode explants from Lathyrus sativus. Callus raised on B5 medium supplemented with 10.7 μM NAA + 2.2 μM BA permitted shoot regeneration upon transfer to modified MS medium containing 10.7 μM NAA + 2.2 μM BA. Rooting was obtained only on 1/2 MS media containing 0.5 μM IBA. The in vitro regenerated plants, after primary and secondary hardening, were taken to the field. Analysis of ODAP in leaves and seeds was carried out. The low toxin containing progeny of the somaclones were further grown in the field. The toxin contents varied from 0.015% to 0.460% in leaf and 0.030% to 0.539% in seed in R, generation, as compared to 0.258% in leaf and 0.406% in seed for the parent P-24. Statistical analysis showed a positive significant correlation between leaf and seed ODAP contents. Mean seed toxin in R1 generation of some of the somaclones varied from 0.039–0.057% and single plant seed yield varied from 25.8 to 45.0 g. Some plants showed seed toxin content of less than 0.01% from 1–22 progeny. Thus, following in vitro culture of internode explant, toxin content in seeds in R2 generation has been found to be substantially reduced with single plant seed yield either equal to or higher than that of parent cv. P 24. 相似文献