Transformations of Pesticides in the Atmosphere: A State of the Art

The current knowledge about transformation rates and products of pesticides in the atmosphere is reviewed. Reactive species and their concentrations in the atmosphere are presented. Reactions of pesticides with these species (including photolysis) in the gas and the particulate phase are evaluated from available experimental data. The potential of estimation methods is discussed. Experimental techniques for laboratory and outdoor measurements are reviewed. Finally, an estimation is made of uncertainties in atmospheric lifetimes due to chemical or physical reactions. It is concluded that the most important transformation of pesticides in the atmosphere is due to reaction with OH radicals. Very few experimental data for pesticides are available though. The levels of uncertainty in OH radical concentrations are acceptable, however, for a proper estimation of atmospheric removal rates due to reactions with OH radicals of those pesticides for which experimental transformation rates (of homologues) are available.     

Partial stem and leaf resistance against the fungal pathogen <Emphasis Type="Italic">Botrytis cinerea</Emphasis> in wild relatives of tomato

Tomato (Solanum lycopersicum) is one of many greenhouse crops that can be infected by the necrotrophic ascomycete Botrytis cinerea. Commercial cultivation of tomato is hampered by the lack of resistance. Quantitative resistance has been reported in wild tomato relatives, mostly based on leaf assays. We aimed to identify wild tomato relatives with resistance to B. cinerea based on quantitative assays both on leaves and stem segments, monitoring infection frequency and disease expansion rate as parameters. A quantitative tomato stem segment assay was developed. This stem assay and a previously described leaf assay were used to screen a collection of 22 Solanum accessions. Significant differences in disease parameters were observed among accessions. Resistance to B. cinerea was observed in a number of wild Solanum species, including accessions of S. chilense, S. habrochaites and S. neorickii, both in the leaf assay and the stem segment assay. A number of resistant and susceptible accessions were evaluated as adult plants under greenhouse conditions. The data obtained in greenhouse assays confirmed the leaf and stem disease data. The expression of several defence-related genes was studied in a subset of accessions. There was no apparent correlation between the expression levels of the genes tested and the quantitative resistance level to B. cinerea. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Effect of omega-3 fatty acids on canine atopic dermatitis

Twenty-nine dogs were included in a double-blinded, placebo-controlled, randomised trial and were orally supplemented for 10 weeks with either flax oil (200 mg/kg/day), eicosapentaenoic acid (50 mg/kg/day) and docosahexaenoic acid (35 mg/kg/day) in a commercial preparation, or mineral oil as a placebo. For each dog, clinical scores were determined based on a scoring system developed prior to the trial. Total omega-6 and omega-3 intake and the ratio of omega-6:omega-3 (omega-6:3) were calculated before and after the trial. The dogs' clinical scores improved in those supplemented with flax oil and the commercial preparation, but not in the placebo group. No correlation was identified between total fatty acid intake or omega-6:3 ratio and clinical scores. Based on the results of this study, the total intake of fatty acids or the omega-6:3 ratio do not seem to be the main factors in determining the clinical response.     

Newly developed primers for the detection of Mycobacterium avium subspecies paratuberculosis

Recent publications reported the existence of IS900 like sequences in mycobacteria different from Mycobacterium avium subspecies paratuberculosis (Map). The primers used for IS900 detection of Map have amplified these sequences causing false positive results. In this study, we have developed two new PCR assays for the detection of Map. The first assay is based on the IS900 sequence using primers different from the ones previously reported, the second assay on the f57 sequence. The specificity of the tests was checked by analysis of 190 mycobacterial isolates (74 Map and 116 non-Map isolates). All Map strains were positive and all non-Map strains were negative. Serial dilutions of Map bacteria were used to assess the sensitivity of the assays. We achieved a sensitivity of 1 CFU per PCR for both assays. In addition, a PCR-simulating computer programme was used to evaluate the specificity of the new IS900 primers.

The combination of the two PCR assays has proven to be useful for the identification of Map but validation on a large range of clinical samples still needs to be done.     

Tomato: a crop species amenable to improvement by cellular and molecular methods

Summary Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures.In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.     

Genetic differences in growth within and between Lycopersicon species

Summary Growth analyses were carried out on 88 accessions of five Lycopersicon species. Experiments were conducted in a climate room at 19/14° C day/night temperature which was irradiated at 20 W/m² for eight hours per day. Large differences in plant weights between wild species and the cultivated tomato were observed from 44 to 84 days after sowing. The increase in plant dry weight could be described by a second order polynomial function. When compared at a standardized plant weight of one gram, the relative growth rates (RGR) of the wild and cultivated accessions ranged from 5.3 to 11.8% and 8.5 to 12.2% per day respectively, limiting the use of wild species as sources for strong growth. When expressed at plant weights of one and three g large differences in decrease of the RGR were observed within L. esculentum. The modern hybrid tomato cultivars were among the fastest growing genotypes, with a relatively slow decrease in RGR.     

肉仔鸡的新型饲料添加剂

随着肉鸡生长速度及饲料转化率的不断提高 ,肉鸡的健康状况 ,特别是其消化功能的问题也日益增多。肉仔鸡的消化功能与肠道内生态系统的状况密切相关。为了防止消化功能紊乱 ,肉鸡饲料中常添加促生长的抗生素。抗生素可提高肉仔鸡的生产性能并提高能量的利用率。但畜禽日粮中使用抗生素 ,造成对人类有致病性的细菌产生抗药性。因此 ,饲料中添加抗生素所引发的争论日渐增多。为了寻找抗生素的替代品 ,首先要了解抗生素的作用机理。1　对微生物的影响抗生素的主要作用是抑制革兰氏阳性菌的生长。然而 ,少有资料表明饲喂添加抗生素的日粮 ,动物…     

RADIOGRAPHIC FINDINGS IN TEN DOGS WITH THORACIC ACTINOMYCOSIS

The radiographic findings in ten dogs with thoracic actinomycosis are presented. Radiographic findins varied, but pleural effusion, pulmonary infiltrates and mediastinal masses were most commonly found. Rib involvement, commonly accompanying actinomycosis in man, was present in only one dog. The differential diagnosis of actinomycosis includes many disease entities, but based on the radiographic signs it may be possible to narrow down the number of possiblities considerably. A combination of mediastinal or pulmonary masses, pleural effusion and encapsulated fluid is strongly indicative for actinomycosis. For confirmation a bacteriological examination is indicated.     

Review of 15 cases of pemphigus foliaceus in horses and a survey of the literature

The records of 15 horses with pemphigus foliaceus diagnosed on the basis of their history, clinical signs, histopathology and the exclusion of differential diagnoses were evaluated with respect to the age of onset, the clinical signs and the diagnostic tests used. There was no apparent breed predisposition. The horses' mean age was nine years, with a range from three months to 25.5 years, three were foals up to six months old and eight were nine years old or older. The most frequent lesions were scaling in 11, crusting in 10 and alopecia in 10, and they appeared most commonly on the face, neck and trunk, in 10 horses for each of these sites. The extremities were involved in nine of the horses, pruritus occurred in seven, and four of the horses had pustules. The clinical signs mostly corresponded with those described in previous reports, but signs of pain were not a prominent feature. Acantholytic cells were identified cytologically in four of six of the horses.     

Histological Studies of Growing and Mature Antlers of Red Deer Stags (Cervus elaphus)

This study aims at presenting histology of growing and mature antlers in red deer stag ( Cervus elaphus ). Growing antlers constitute a model organ for examining regeneration processes of tissues because they are the only mammalian appendages capable of regeneration. Histological study revealed that the tip of a growing antler consists of hairy skin, perichondrium, mesenchyme and chondroprogenitors area. By performing immunochistochemistry, we found that cell expressing Ki-67 and PCNA antigens were localized in basal layer of epidermis, skin glands and beneath their secretory sections, mesenchyme as well as within and in the vicinity of central blood vessels. Ultrastructurally, cells from chondroprogenitors zone have chondroblast-like morphology and take part in producing of collagen fibres followed by the process of cartilage mineralization. However, mature antlers also consist of lamellar osseous tissue.