Herbicidal activity of phosphonic and phosphinic acid analogues of glutamic and aspartic acids     

Dorota Miliszkiewicz  Piotr Wieczorek  Barbara Lejczak  Ewa Kowalik  Pawel Kafarski 《Pest management science》1992,34(4):349-354

Phosphonic and phosphinic acid analogues of glutamic and aspartic acids were synthesized and screened for herbicidal activity on Lepidium sativum L. Depending on the chemical structure, they exhibited significant or moderate herbicidal activity against L. sativum roots (with some representatives being equipotent with phosphinothricin), while their influence on shoot growth was negligible. Cucumis sativus L. appeared to be more tolerant to these analogues. The origin of this selectivity remains to be determined.  相似文献   

Co² laser oophorectomy of a sertoli cell tumor and dissection of a hydatid cyst of morgagni of the infundibulum of a uterine tube in a mare: A case report     

Tom C. Montgomery  Barbara Weakley-Jones 《Journal of Equine Veterinary Science》1984,4(5):200-201

  相似文献   

Archaeology. Roiled by smuggling charge,Egypt dig to continue     

Casassus B 《Science (New York, N.Y.)》2003,301(5635):902

  相似文献   

The basic biology of malignant melanoma: molecular mechanisms of disease progression and comparative aspects   总被引：2，自引：0，他引：2  

Sulaimon SS  Kitchell BE 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(6):760-772

Malignant melanoma (MM) is a life-threatening disease characterized by a highly aggressive biologic behavior in both humans and dogs. Despite improvements in diagnosis and patient care, most deaths from MM are due to metastases that are resistant to conventional treatment modalities. To ultimately reduce the mortality associated with metastatic disease, it is necessary to better define the fundamental molecular mechanisms of malignant tumor progression. The progression of disease is a consequence of the complex interactions between malignantly transformed cells and host factors. Characterization of the stages of tumor progression and the changes occurring in highly malignant cells is important for the development of effective treatment regimens. The dys-regulated molecular mechanisms of transformed melanocytes are presently being characterized. In this review, we summarize the current understanding of the molecular phases in the progression of MM, which include genetic instability, dysregulated proliferation of melanocytes, increased invasion and metastasis, and angiogenesis.  相似文献   

Clostridium sordelli infection as a suspected cause of transient hyperammonemia in an adult horse     

Desrochers AM  Dallap BL  Wilkins PA 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(2):238-241

  相似文献   

Efficacy of extended pirlimycin therapy for treatment of experimentally induced Streptococcus uberis intramammary infections in lactating dairy cattle   总被引：1，自引：0，他引：1  

Oliver SP  Almeida RA  Gillespie BE  Ivey SJ  Moorehead H  Lunn P  Dowlen HH  Johnson DL  Lamar KC 《Veterinary therapeutics : research in applied veterinary medicine》2003,4(3):299-308

Streptococcus uberis is an important cause of mastitis in dairy cows throughout the world, particularly during the dry period, around the time of calving, and during early lactation. Strategies for controlling S. uberis mastitis have not received adequate research attention and are therefore poorly defined and inadequate. Objectives of the present study were to evaluate the efficacy of extended therapy regimens with pirlimycin for treatment of experimentally induced S. uberis intramammary infections in lactating dairy cows during early lactation and to evaluate the usefulness of the S. uberis experimental infection model for evaluating antimicrobial efficacy in dairy cows. The efficacy of extended pirlimycin intramammary therapy regimens was investigated in 103 mammary glands of 68 dairy cows that became infected following experimental challenge with S. uberis during early lactation. Cows infected with S. uberis in one or both experimentally challenged mammary glands were randomly allocated to three groups, representing three different treatment regimens with pirlimycin, including 2-day (n = 21 cows, 31 mammary quarters), 5-day (n = 21 cows, 32 quarters), and 8-day (n = 26 cows, 40 quarters). For all groups, pirlimycin was administered at a rate of 50 mg of pirlimycin hydrochloride via intramammary infusion. A cure was defined as an experimentally infected mammary gland that was treated with pirlimycin and was bacteriologically negative for the presence of S. uberis at 7, 14, 21, and 28 days after treatment. Experimental S. uberis intramammary infections were eliminated in 58.1% of the infected quarters treated with the pirlimycin 2-day regimen, 68.8% for the 5-day regimen, and 80.0% for the 8-day regimen. Significant differences (P <.05) in efficacy were observed between the 2-day and 8-day treatment regimens. The number of somatic cells in milk decreased significantly following therapy in quarters for which treatment was successful in eliminating S. uberis. However, there was no evidence to suggest that extended therapy with pirlimycin resulted in a greater reduction in somatic cell counts in milk than the 2-day treatment. The S. uberis experimental infection model was a rapid and effective means of evaluating antimicrobial efficacy during early lactation at a time when mammary glands are highly susceptible to S. uberis intramammary infection.  相似文献   

Activity levels and predator detection by amphipods infected with an acanthocephalan parasite, Pomphorhynchus laevis     

Dezfuli BS  Maynard BJ  Wellnitz TA 《Folia parasitologica》2003,50(2):129-134

The acanthocephalan parasite Pomphorhynchus laevis (Müller, 1776) uses freshwater amphipods as its intermediate host. In order to complete the life cycle, the infected amphipod must be consumed by a fish, where the acanthocephalan will mature and reproduce. Parasite transmission, and therefore fitness, could be enhanced if infected amphipods fail to detect or avoid predatory fish. We compared the activity levels of infected and non-infected amphipods, Echinogammarus stammeri (Karaman, 1931), in both the presence and absence of odours from its natural, definitive host, the fish Leuciscus cephalus (L.). Throughout the experiment, infected amphipods were more active than were non-infected individuals. The non-infected amphipods reduced their activity after the addition of fish odours, but the infected amphipods failed to show a significant decrease. The failure of infected amphipods to reduce activity levels in the presence of fish odour may reflect a parasite strategy to increase its chances of transmission by making its amphipod host more vulnerable to predation by fish.  相似文献   

Isolates of Verticillium dahliae Pathogenic to Crucifers Are of at Least Three Distinct Molecular Types     

Collins A  Okoli CA  Morton A  Parry D  Edwards SG  Barbara DJ 《Phytopathology》2003,93(3):364-376

ABSTRACT Diverse isolates of the soilborne wilt fungi Verticillium dahliae and V. albo-atrum were studied to understand the nature and origins of those infecting cruciferous hosts. All isolates from cruciferous crops produced microsclerotia, and the majority produced long conidia with a high nuclear DNA content; these isolates were divided into two groups by amplified fragment length polymorphism (AFLP) analysis. One group could be subdivided by other criteria such as rRNA sequences and mitochondrial DNA restriction fragment length polymorphism (RFLP) analysis. Two crucifer isolates were short spored and had a low nuclear DNA content. The results are consistent with the crucifer isolates being interspecific hybrids. The long-spored isolates are best regarded as amphihaploids (or allodiploids) with the AFLP groups probably each representing separate interspecific hybridization events. The short-spored crucifer isolates appear to be derived from interspecific hybrids and are here called 'secondary haploids'. Molecular evidence suggests that one parent in the crosses was similar to V. dahliae. The other parent of the amphihaploids seems to have been more similar to V. albo-atrum than to V. dahliae, but was distinct from all isolates of either species so far studied. The implications for the taxonomy of crucifer isolates are discussed and the use of the name V. longisporum, proposed elsewhere for just some of these isolates, is discouraged.  相似文献   

Genetic diversity and pathogenic variability among isolates of colletotrichum species from strawberry     

Denoyes-Rothan B  Guérin G  Délye C  Smith B  Minz D  Maymon M  Freeman S 《Phytopathology》2003,93(2):219-228

ABSTRACT Ninety-five isolates of Colletotrichum including 81 isolates of C. acutatum (62 from strawberry) and 14 isolates of C. gloeosporioides (13 from strawberry) were characterized by various molecular methods and pathogenicity tests. Results based on random amplified polymorphic DNA (RAPD) polymorphism and internal transcribed spacer (ITS) 2 sequence data provided clear genetic evidence of two subgroups in C. acutatum. The first subgroup, characterized as CA-clonal, included only isolates from strawberry and exhibited identical RAPD patterns and nearly identical ITS2 sequence analysis. A larger genetic group, CA-variable, included isolates from various hosts and exhibited variable RAPD patterns and divergent ITS2 sequence analysis. Within the C. acutatum population isolated from strawberry, the CA-clonal group is prevalent in Europe (54 isolates of 62). A subset of European C. acutatum isolates isolated from strawberry and representing the CA-clonal and CA-variable groups was assigned to two pathogenicity groups. No correlation could be drawn between genetic and pathogenicity groups. On the basis of molecular data, it is proposed that the CA-clonal subgroup contains closely related, highly virulent C. acutatum isolates that may have developed host specialization to strawberry. C. gloeosporioides isolates from Europe, which were rarely observed were either slightly or nonpathogenic on strawberry. The absence of correlation between genetic polymorphism and geographical origin in Colletotrichum spp. suggests a worldwide dissemination of isolates, probably through international plant exchanges.  相似文献   

Growing vegetables in developing countries for local urban populations and export markets: problems confronting small-scale producers     

Dinham B 《Pest management science》2003,59(5):575-582

Vegetables attract high applications of pesticides, and farmers in developing countries use many acutely toxic insecticides to control pests on these crops. With the liberalisation of agricultural markets in developing countries, the number of small-scale farmers growing vegetables for both domestic and export markets is increasing. Demand for supplies of year-round and exotic fruit and vegetables has grown in industrialised countries, but with rising quality standards and traceability requirements it is difficult for small-scale farmers to benefit from this lucrative non-traditional agricultural export trade. The demand is high for vegetables in the expanding cities in developing countries, and farmers in peri-urban areas, or rural areas with good access to the cities, are in a position to find a growing market for their produce. Poor storage facilities will often mean that farmers are forced to sell at peak times when prices are low. Farmers rarely have access to training in pesticide use, and have only limited or no access to advice on the complicated management of pesticides. The Food and Agriculture Organisation of the UN is concerned about high levels of poor quality and adulterated pesticides on sale in developing countries. Surveys repeatedly show that without training, farmers are unable to make good crop decisions: recognition of pests and their predators is generally low, leading to decisions to spray to kill any insect; knowledge of product selection, application rates and timing is poor; different products are often combined in the belief that the effect will be greater; re-entry periods after spraying and essential harvest intervals are not known; and without knowledge of alternatives, farmers will often assume that the only solution to pest problems is to spray more frequently. From a consumer's point of view, few developing countries are able to monitor pesticide residues, particularly for produce grown for home consumption: most countries do not have laboratories for even simple residue testing. Changes in European Maximum Residue Limits means that export crops will be rejected if they contain residues at the Limit of Detection of pesticides not registered in Europe. Season-long field level training in Integrated Pest Management can help farmers to become better decision-makers, and to greatly reduce pesticide use while reducing risks to their own health and environment, producing safer products for consumers, maintaining yields, and increasing incomes.  相似文献