Pathogens and their products affecting weedy plants

There are many natural enemies of weedy plants; among them are plant pathogens. Plant pathogens are capable of affecting plants, in part because of the phytotoxins they produce. Phytoloxins of weedy pathogens are produced in culture media by most of the phytopathogenic fungi of weeds that we have studied. In most cases the phytotoxin(s) usually belongs to a family of related compounds produced by the pathogen. Phytotoxin production in the medium can be optimized by placement of the host extract into the medium. Lethal activity is usually observed in the concentration range of 10^-3-10^-6M. The concept of using these molecules, or derivatives thereof, or related compounds as herbicides, should be explored.     

Environmental degradation of the insect growth regulator methoprene: V. Metabolism by houseflies and mosquitoes

The metabolism of methoprene (I, isopropyl (2E,4E)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate, trademark Altosid) was investigated in larval mosquitoes and houseflies. The most abundant primary metabolite in third- and fourth-instar Aedes and fourth-instar Culex larvae was the hydroxy ester while the hydroxy acid predominated in third-instar Musca larvae. Biological isomerization of the double bond at C-2 in I (i.e., conversion of (E) to (Z)) was an effective mode of insect detoxication, but these dipterans apparently cannot isomerize the (2Z) isomer of I to methoprene. In general, piperonyl butoxide and triorthocresyl phosphate slightly increased the morphogenetic activity of I in these insects.     

Pathological findings in dogs naturally infected with Angiostrongylus vasorum in Newfoundland and Labrador, Canada.

Fifty-six dogs from St. John's, Newfoundland, Canada, were evaluated for Angiostrongylus vasorum infection. Small numbers of nematodes were found within pulmonary arteries of 6 dogs. Larvae were identified in fecal samples in 2 of 6 dogs. All 6 dogs had multifocal granulomatous pneumonia and sometimes foci of chronic thrombosis, which varied from very mild to severe. One dog had extensive pulmonary lesions resulting in cor pulmonale. Right heart failure was characterized by right ventricular hypertrophy, hepatic congestion, ascites, and hydrothorax. Microscopically, in most cases, eggs, larvae, and sometimes intravascular adults, were present within lung tissue sections. Small foci of granulomatous inflammation with and without larvae were present in kidney and brain in 4 dogs. An additional dog, diagnosed antemortem with angiostrongylosis via fecal examination, was also examined. Pathological findings consisted of severe pyogranulomatous interstitial pneumonia with myriad eggs, larvae, and numerous intravascular pulmonary adult nematodes with extensive arterial thrombosis. Five hundred and seventy-two adult worms were removed from pulmonary arteries. Foci of granulomatous inflammation, often associated with larvae and/or eggs, were present in tracheobronchial lymph nodes, adrenal gland, brain, and kidneys. Severe seizuring noted antemortem was attributed to several large, discrete areas of acute hemorrhagic infarction within the cerebrum and cerebellum. Natural A. vasorum infection in domestic dogs in eastern Newfoundland causes lung pathology of variable severity, which in some cases, may progress to cor pulmonale and which may be associated with extrapulmonary lesions and clinical signs.     

Determinants of the degradation of soil structure in vineyards with a view to conversion to organic farming

In perennial crops such as grapevine, there is a considerable risk of soil degradation caused by mechanization. Organic farming may increase traffic and result in more intensive soil structure degradation, especially on wet soil. Soil structure was observed in 69 soil profiles from 12 vineyards (Languedoc‐Roussillon, Bordeaux, Provence, Burgundy, Rhône Valley) to study the relationships between permanent soil characteristics (texture, stoniness, waterlogging), cultivation practices (technical operations, traffic, farm equipment) and soil structure. Compaction zones were identified in soil profiles viewed perpendicularly to the grapevine rows. The percentage of compacted area and a score for compaction intensity were assessed in the top 0.5 m of the soil profile in three soil compartments defined by the distance from the grapevine row: (1) 0 to 0.2 m (2) 0.2 m to 0.5 m and (3) 0.5 m to the middle of the inter‐row. Most soil profiles exhibited considerable compaction: 75% of the soil profiles were compacted in compartments 2 or 3. Intensity correlated with depth of compaction in compartment 2 – the deeper the compaction, the greater the compaction intensity. Four types of soil profiles could be identified, depending on the location of compacted zones and of their intensity of compaction. The factors that determined the types of soil profiles were as follows: soil vulnerability to compaction, use of moderating practices (practices that limit the risk of compaction) and traffic geometry. A statistical analysis resulted in a decision tree that provides a useful basis to choose cultivation practices that limit damage to or improve soil structure.     

当今全球食品新产品开发趋势

虽然全球经济形势依然严峻,但食品新产品开发却保持强劲势头。据总部在荷兰的全球消费者调研机构Innova Market Insights公司的市场调查,2009年新产品上市量比2008年至少增长15%。展望未来,一些新产品的主要发展趋势和方向变得逐渐明朗,它们很可能对未来全球食品产业市场产生深远影响。根据对市场的分析,Innova Market Insights公司提出了当今全球食品十大新产品发展趋势。     

人类在禽病流行中所扮演的角色

彻底阐明疾病从人向家禽传播的途径并不是一件困难的事,但要防止家禽疾病暴发还需要走很长的路。