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911.
Tahereh Karami Jamour 《Biocontrol Science and Technology》2012,22(1):101-110
The functional response of adult females of the coccinellid beetle Stethorus gilvifrons Mulsant to juveniles of strawberry spider mite, Tetranychus turkestani Ugarov & Nikolski was determined on cowpea, castor bean and cucumber leaves in the laboratory at 25°C and a 14 h L: 10 h D photoperiod. Beetles were isolated singly for 24 h in 9-cm Petri dishes with either 2, 4, 8, 16, 32, 64, or 128 nymphal stages of T. turkestani. Results showed a typical type II response on all plants tested, with up to 110.7, 100.8, and 53.0 prey attacked when 128 nymphal stages were provided on cowpea, castor bean, and cucumber leaves, respectively. Based on the Rogers random attack equation, the highest estimated attack rate and the lowest handling time were obtained on cowpea. It was therefore concluded that the host plant species can affect the predation rate and functional response components of S. gilvifrons, a specific and effective predator of spider mites. 相似文献
912.
P34, a storage protein and major soybean allergen, has undergone a functional transition from a cysteine peptidase to a syringolide receptor. An exploration of the evolutionary mechanism of this functional transition is made. To identify homologous genes of P34, syntenic network was constructed using syntenic relationships from the Plant Genome Duplication Database. The collected homologous genes, along with SPE31, a highly homologous protein to P34 from the seeds of Pachyrhizus erosus, were used to construct a phylogenetic tree. The results show that multiple gene duplications, exon shuffling and following granulin domain loss and some critical point mutations are associated with the functional transition. Although some tests suggested the existence of positive selection, the possibility that random fixation under relaxation of purifying selection results in the functional transition is also supported. In addition, the genes Glyma08g12340 and Medtr8g086470 may belong to a new group within the papain family. 相似文献
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Catherine J Hutchings Gabriella Cseke Greg Osborne Jeanette Woolard Andrei Zhukov Markus Koglin Ali Jazayeri Jahnavi Pandya-Pathak Christopher J Langmead Stephen J Hill Malcolm Weir Fiona H. Marshall 《MABS-AUSTIN》2014,6(1):246-261
Thermostabilized G protein-coupled receptors used as antigens for in vivo immunization have resulted in the generation of functional agonistic anti-β1-adrenergic (β1AR) receptor monoclonal antibodies (mAbs). The focus of this study was to examine the pharmacology of these antibodies to evaluate their mechanistic activity at β1AR. Immunization with the β1AR stabilized receptor yielded five stable hybridoma clones, four of which expressed functional IgG, as determined in cell-based assays used to evaluate cAMP stimulation. The antibodies bind diverse epitopes associated with low nanomolar agonist activity at β1AR, and they appeared to show some degree of biased signaling as they were inactive in an assay measuring signaling through β-arrestin. In vitro characterization also verified different antibody-receptor interactions reflecting the different epitopes on the extracellular surface of β1AR to which the mAbs bind. The anti-β1AR mAbs only demonstrated agonist activity when in dimeric antibody format, but not as the monomeric Fab format, suggesting that agonist activation may be mediated through promoting receptor dimerization. Finally, we have also shown that at least one of these antibodies exhibits in vivo functional activity at a therapeutically-relevant dose producing an increase in heart rate consistent with β1AR agonism. 相似文献
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In the Okavango Delta 98–99% of the water from inflow and rainfall is lost to the atmosphere through evapotranspiration. As
a consequence 94% of inflowing solutes are retained within the Delta landscape. This process might be expected to result in
an entirely saline environment, but that is not the case: the surface waters have very low salinity, supporting a typical
freshwater biota. It has been deduced that the numerous islands in the Delta (about 150,000 within an area of 13,500 km2) have been formed through evapotransporative concentration in the groundwater, of infiltrating solutes, followed by precipitation
and volume increase. Evidence of this is the large amount of calcrete in island soils. These islands of 3–10 m thickness with
clayey soils are underlain by fine Kalahari sand to a depth of 200–300 m, which also indicates that they are formed through
surface processes. The infiltration rate of surface water from floodplains and streams into islands is very high, and is predominantly
a lateral process that is unidirectional. Evapotranspiration in the riparian woodland zone cause the ground-waters in the
central area of islands—with halophyte grasslands—to have very high salinities. By use of chloride as a conservative element
the concentration factor between central island groundwater and surface water is calculated to be 500–1,000. This groundwater
is depleted of calcium and magnesium supporting the early deductions that these elements have precipitated as calcrete. There
is also a large depletion of silicate and potassium that probably have precipitated as well forming the clayey soils typical
of the islands. The central island groundwater is dominated by sodium, bicarbonate and dissolved organic matter. The gradual
increase of salinity here causes a periodic let off of this water through a density-driven process to deeper layers. This
process together with island growth through precipitation of solutes are the two major sink processes of inflowing solutes
and explains why the Okavango Delta is at present a freshwater system. The whole island complex is calculated to be 100,000–400,000 years
old while some intensely studied islands may be younger: 80,000–240,000 years. The discrepancy is explained by a biassed selection
of islands currently in flooded areas with better growth conditions. The uniqueness of the Okavango Delta and ideas for future
research are discussed. 相似文献
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