Improved chemical control of Conyza bonariensis in wheat limits problems in the following fallow     

Steven Walker  Michael Widderick  Andrew McLean  Tony Cook  Bill Davidson 《Weed Biology and Management》2013,13(4):144-150

Conyza bonariensis is a major weed infesting zero‐tilled cropping systems in subtropical Australia, particularly in wheat and winter fallows. Uncontrolled C. bonariensis survives to become a problem weed in the following crops or fallows. As no herbicide has been registered for C. bonariensis in wheat, the effectiveness of 11 herbicides, currently registered for other broad‐leaved weeds in wheat, was evaluated in two pot and two field experiments. As previous research showed that the age of C. bonariensis, and to a lesser extent, the soil moisture at spraying affected herbicide efficacy, these factors also were investigated. The efficacy of the majority of herbicide treatments was reduced when large rosettes (5–15 cm diameter) were treated, compared with small rosettes (<5 cm diameter). However, for the majority of herbicide treatments, the soil moisture did not affect the herbicide efficacy in the pot experiments. In the field, a delay in herbicide treatment of 2 weeks reduced the herbicide efficacy consistently across herbicide treatments, which was related to weed age but not to soil moisture differences. Across all the experiments, four herbicides controlled C. bonariensis in wheat consistently (83–100%): 2,4‐D; aminopyralid + fluroxypyr; picloram + MCPA + metsulfuron; and picloram + high rates of 2,4‐D. Thus, this problem weed can be effectively and consistently controlled in wheat, particularly when small rosettes are treated, and therefore C. bonariensis will have a less adverse impact on the following fallow or crop.  相似文献   

Insulin Resistance in Standard Donkeys (Equus asinus) of Three Body Conditions-Thin,Moderate, and Obese     

A.K. McLean  B.D. Nielsen  M. Yokoyama  C.I. O′Connor-Robison  S. Hengemuehle  W. Wang  R. Geor  P.A. Harris 《Journal of Equine Veterinary Science》2009

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Seasonal differences in the incidence of infection with Fasciola gigantica in cambodian cattle     

Suon S  Hol D  Siek S  McLean M  Copeman B 《Tropical animal health and production》2006,38(1):23-28

Farmer's cattle were treated with triclabendazole and used as tracer animals to detect new infections with Fasciola gigantica in three villages located on the bank of the Bassac River (a major tributary of the Mekong River) and in a fourth village located on farmland away from the river, from April 1999 until January 2001. The month of infection was estimated by subtracting 4 months from the date when eggs of F. gigantica were detected in faeces. Farmers were interviewed each month to record the nature of the agricultural and animal husbandry activities that occurred during the previous month, especially events that might have exposed cattle to infection with F. gigantica. Results support the conclusions that infection of cattle in riverbank villages acquired from about August or September until November originated from herbage and water in irrigation canals and dams on the riverbank, and that the progressively increasing monthly incidence from December until April (up to 87% per month in April 2000) was derived from herbage and water in recently harvested rice fields and lakes adjacent to the riverbank. The abrupt cessation of new infection in riverbank villages in May coincided with flooding of low-lying land, the movement of cattle to land above flood height on the riverbank, and a change of diet to dry-land crop residues, stored dry rice stalks, and herbage and water that were unlikely to contain metacercariae. It was concluded that snails in dams and canals on the riverbank became infected with F. gigantica after cattle were moved to the riverbank in May, and cercariae shed from these snails provided the new infections that occurred in cattle in August and September. In the village located away from the river, infection of cattle between September and March coincided with the rice harvest, supporting the conclusion that feeding of fresh rice stalks and stubble after the rice was harvested was the main source of infection. The low monthly incidence observed (up to 6.4% per month) was consistent with the hypothesis that snails did not survive in the dry rice fields between crops and that few snails would have been available from the small number of aquatic refuges that persisted through the dry season to recolonize rice fields during the wet season. Between April and August there was no opportunity for new infection because cattle were fed forage from around houses and headlands, and on dry-land crop residues and stored dry rice stalks. Control of fasciolosis was proposed using a single treatment of cattle with triclabendazole in riverbank villages in May when cattle were moved to the riverbank, and after harvest of the last rice field in villages located away from the river.  相似文献   

Basis for antagonism by sodium bentazon of tritosulfuron toxicity to white bean (Phaseolus vulgaris L.)     

Weinberg T  Stephenson GR  McLean MD  Satchivi NM  Hall JC 《Journal of agricultural and food chemistry》2007,55(6):2268-2275

White bean (Phaseolus vulgaris L.) was used to study the antagonism caused by Na-bentazon on the phytotoxic action of the sulfonylurea (SU) herbicide tritosulfuron. After 168 h, uptake and translocation of [14C]tritosulfuron were reduced by 60 and 89%, respectively, when Na-bentazon was added to the mixture. Addition of (NH4)2SO4 or replacement of Na-bentazon with NH4-bentazon completely eliminated the negative effects on [14C]tritosulfuron uptake but not on its translocation. Scanning electron microscopy revealed that a mixture of Na-bentazon plus tritosulfuron plus DASH HC (0.156%) formed a rough layer of grain-like crystals on the leaf surface, whereas the addition of (NH4)2SO4 or replacement of Na-bentazon with NH4-bentazon resulted in amorphous deposits that may be more easily absorbed. The antagonism of tritosulfuron's phytotoxicity by Na-bentazon involves two separate processes, chemical (uptake effect) and biochemical (translocation effect).  相似文献   

Punishment in horse-training and the concept of ethical equitation     

Paul D. McGreevy  Andrew N. McLean 《Journal of Veterinary Behavior: Clinical Applications and Research》2009,4(5):193-197

By definition, punishment makes a response less likely in the future. Because horses are largely trained by negative reinforcement, they are susceptible to inadvertent punishment. Delays in the release of pressure can make desirable responses less likely and thus punish them. This study examines the correct use of negative reinforcement and identifies a continuum between poorly timed negative reinforcement and punishment. It explores some of the problems of non-contingent punishment and the prospect of learned helplessness and experimental neurosis. It concludes by introducing the concept of ethical equitation.  相似文献   

FEEDING PLANTS MANGANESE THROUGH THE STOMATA     

McLean FT 《Science (New York, N.Y.)》1927,66(1716):487-489

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Screening method for vitamins A and D in fortified skim milk, chocolate milk, and vitamin D liquid concentrates     

S K Henderson  L A McLean 《Journal of the Association of Official Analytical Chemists》1979,62(6):1358-1360

Vitamin A was determined in fortified chocolate milk and skim milk; vitamin D was determined in fortified chocolate milk, skim milk, and vitamin D concentrates, using reverse phase high pressure liquid chromatography (HPLC). The sample is saponified, extracted with hexane, and chromatographed in an HPLC system on a 10 micron Vydac TP reverse phase C18 column, using acetonitrile-methanol (9+1) as the mobile phase. For 6 replicates, the recoveries of vitamins A and D, using this procedure, were 99 and 98%, respectively.  相似文献   

Relatedness does not affect the mating effort of Eisenia fetida Sav. (Oligochaeta) despite evidence for outbreeding depression     

Shinichi Nakagawa  Terry D. Bannister  Fiona R. Jensen  Donald A. McLean  Joseph R. Waas 《Biology and Fertility of Soils》2002,35(5):390-392

Animals that can distinguish kin from non-kin may enhance their breeding success through "optimal outbreeding". Although relatedness can influence the breeding success of earthworms, no studies of kin discrimination have been conducted in any Oligochaeta species. We determined whether Eisenia fetida Sav. would discriminate kin and change breeding effort with them. The number of cocoons produced (fecundity), viable cocoons, and hatchlings produced by full sibling (inbreeding) and non-sibling (outbreeding) pairs, from different populations, were compared; in this species, fecundity is a reliable indicator of the occurrence and frequency of mating. There were no significant differences in fecundity between inbreeding and outbreeding pairs, so we obtained no evidence for differential investment based on kinship. However, sibling pairs hatched a significantly greater proportion of their cocoons than non-sibling pairs, suggesting that outbreeding depression may reduce reproductive success. We also provide the first evidence for the possibility of parthenogenesis in this species.  相似文献   

Increasing expression of an anti-picloram single-chain variable fragment (ScFv) antibody and resistance to picloram in transgenic tobacco (Nicotiana tabacum)     

Olea-Popelka F  McLean MD  Horsman J  Almquist K  Brandle JE  Hall JC 《Journal of agricultural and food chemistry》2005,53(17):6683-6690

Systematic research involving four chimeric gene constructions designed to express the same anti-picloram single-chain variable fragment (scFv) antibody is described. Agrobacterium-mediated transformation produced at least 25 transgenic tobacco plants with each of these, and the number of T-DNA loci in each plant was determined using kanamycin-resistance segregation assays. The relative amounts of active and total scFv in each plant were evaluated using quantitative enzyme-linked immunosorbent assay and immunoblot technologies, respectively. No significant differences in scFv activity were found among the four groups of single-locus plants, although the 35S/M construct was found to produce significantly more total anti-picloram scFv than the other three constructs. A dose-response bioassay involving T(1) seedlings from several of the highest expressers of active scFv demonstrated resistance to a constant exposure of picloram at 5 x 10(-)(8) M. Other approaches for increasing antibody-based herbicide resistance are discussed, as further improvements are needed before practical application of this technology.  相似文献   

The effects of protein level on cytokines and chemokines in the uterine environment of beef heifers during development     

Taylor B Ault-Seay  Taylor D Harrison  Kiernan J Brandt  Rebecca R Payton  Liesel G Schneider  Phillip R Myer  Justin D Rhinehart  Louisa A Rispoli  Kyle J McLean 《Journal of animal science》2021,99(6)

The development of replacement heifers is crucial for breeding success and herd efficiency. Nutritional management can affect not only reproductive development but also the inflammatory status of the uterine environment, which may impact reproductive functions such as pregnancy establishment and development. The study herein evaluated the concentration of cytokines and chemokines in the uterus of heifers supplemented with different levels of protein. Angus heifers (n = 60) were blocked by body weight (BW) and randomly assigned to 1 of 3 treatments based on protein supplementation level: control of 10% crude protein (CON), 20% crude protein (P20), or 40% crude protein (P40). BW, body condition score, and blood samples were taken every 2 wk for 140 d to monitor development. Uterine flushes were performed monthly and concentrations of cytokines (IL-1α, IL-1β, TNF-α, IFN-γ, IL-10, VEGF-α, IL-17A, and IL-36RA) and chemokines (IL-8, MCP-1, MIP-1α, and MIP-1β) were quantified via ELISA multiplex. To test if there were mean differences in cytokines between the treatment groups or over time, PROC GLIMMIX (SAS v 9.4) was utilized. Concentrations of all cytokines and chemokines, except IL-1α, changed throughout heifer development (P < 0.05). Heifers in the P40 treatment group displayed reduced concentrations of MCP-1 (P = 0.007) and tended to have decreased concentrations of IFN-γ (P = 0.06). Cytokine IL-36RA tended (P = 0.06) to be affected by protein level, with the lowest concentrations observed in CON heifers. Most cytokines and chemokines increased following the initial month of supplementation (P < 0.05). The increase in concentrations after 1 mo may indicate an adaptive response in the uterus to diet change. Cytokines and chemokines fluctuated due to physiological changes occurring during development. Further research is needed to determine the influence of nutrition on uterine inflammation and long-term impacts on reproductive function.  相似文献