Genetic conversion of a fungal plant pathogen to a nonpathogenic, endophytic mutualist

The filamentous fungal ascomycete Colletotrichum magna causes anthracnose in cucurbit plants. Isolation of a nonpathogenic mutant of this species (path-1) resulted in maintained wild-type levels of in vitro sporulation, spore adhesion, appressorial formation, and infection. Path-1 grew throughout host tissues as an endophyte and retained the wild-type host range, which indicates that the genetics involved in pathogenicity and host specificity are distinct. Prior infection with path-1 protected plants from disease caused by Colletotrichum and Fusarium.Genetic analysis of a cross between path-1 and wild-type strains indicated mutation of a single locus.     

The genealogy of British poultry science

The first issue of British Poultry Science was published in April 1960. In this paper the origin and development of the Journal and the organisations with which it has been associated are traced.     

Assessment of Iowa farmers' perceptions about auger safety

A survey of Iowa farmers was conducted to assess the farmers' perceptions and beliefs regarding auger safety and how these perceptions are put into practice. A questionnaire was designed to obtain information on the following auger-related topics: recognition of safe practices and appropriate shielding, personal practices and behaviors, risk perception, and personal beliefs. A random sample of 400 Iowa farmers (arrayed by county) was selected to be representative of Iowa farms. The response to the mailed survey was 23%. Some returned surveys were eliminated because the respondent was retired or did not own/operate augers, resulting in 57 usable questionnaires. Survey responses indicate that the majority of Iowa farmers who participated in this study can correctly identify appropriate shielding for auger intake that meet or exceed ASAE standards. Survey responses suggest that it is common practice in Iowa for youth (age 13 to 19) to operate augers. Iowa farmers in this study perceive the most important contributing factors to auger-related injuries to be operating an auger without shielding, failure to pay attention on the job, moving augers in a raised position, and using hand or feet to redirect the flow of grain. Survey results also indicate that carelessness is perceived to be the leading cause of auger-related injuries, and that auger related injuries can be avoided by having respect for the equipment, being careful, and using common sense. The results also show that the Iowa farmers who participated in this study commonly perform auger-related practices (e.g., moving an auger in a raised position) that they identify as being unsafe.     

Molecular weight spectra of dissolved organic carbon in a rewetted Welsh peatland and possible implications for water quality

Abstract. Demand for water from catchments dominated by upland peat as a source of drinking water supplies in the UK is likely to increase in the future as demand per capita continues to rise (Thomsen 1990) and/or summer droughts increase in frequency (Arnell 1992). Concern has been expressed in recent years over rising colour levels (related to dissolved organic carbon (DOC) and iron (Fe)) from such catchments (e.g. Kay et al. 1989) causing reduced drinking water quality. One of the major causes of increased DOC concentrations is rewetting following periods of relative drought (Mitchell & McDonald 1992). Experimental rewetting of a naturally drained wetland in Mid‐Wales over four years was found to substantially increase the concentrations of DOC, and Fe in the pore‐water, with peak values of >60 mg dm^–3 (Fe) and >300 mg dm^–3 (DOC) after rewetting, compared with typical values of <1 mgdm^–3 (Fe) and <15 mg dm^–3 (DOC) under the drained conditions. Seasonal peak concentrations of Fe and DOC have since remained at these higher levels. Rewetting produced a selective enrichment of the >5000 to <90 000 apparent molecular weight (AMW) material and this fraction was found to yield peak Fe concentrations. Two additional peaks of DOC were also found in the experimental wetland (not present in the control wetland), of >90 000 to <200 000 AMW and >200 000 AMW material. The AMW spectrum of DOC in the experimental wetland changed with season, and the >90 000 to <200 000 AMW fraction could only be seen in spring, representing a transient pool of carbon that is rapidly transformed in or transported from the wetland. These findings suggest that rewetting of peatland following drought (e.g. due to climate change) has the potential to reduce water quality. Moreover, recent interest in restoration (rewetting) of drained peatlands (Wheeler & Shaw 1995) could create an additional source of DOC rich water.     

A Case of Bovine Linear Keratosis

Résumé— Cet article décrit un cas de nevus épidermique linéaire unilatéral chez un veau de six mois. Histologiquement, les lésions consistaient en une alternance de zones d'hiper et de parakératose avec une inflammation dermique distincte. Le diagnostic de nevus linéaire inflammatoire a été posé sur la base des lésions macro et microscopiques. [Deprez, P., De Coole, H., Sustronk, B., Muille, E., Ducatelle, R. A case of bovine linear keratosis (A propos d'un cas de kératose linéaire chez un bovin).
Resumen— En este artículo se describe un caso de nevos epidérmicos lineares unilaterales en un bo vino de seis meses de edad. Las lesiones histológicas consistian zonas donde se alternaba hiper i paraqueratosis, mientras que la dermis presentaba una marcada inflamación. Se diagnosticó un nevo epidérmico verrucoso linear e inflamatorio a partir de las lesiones clinicas e histopatológicas [A case of bovine linear keratosis (Un caso de queratosis linear bovina).
Abstract— This report describes a case of unilateral linear epidermal nevi in a 6-month-old bovine. Histologicalli, the lesions consisted of alternating areas of hiper- and parakeratosis with a distinct dermal inflammation. A diagnosis of inflammatori linear verrucous epidermal nevus was made based on the clinical and histopathological lesions.     

A genetic description of two selected strains of rabbits

Two strains of rabbits (strains 1077 and 2066) have been selected since 1974 for increased litter size. Each strain is split into a fixed number of reproduction groups. The mating scheme is similar to random non-sib herd mating. The number of animals per generation is higher in strain 1077 (28 mated bucks and 104 mated does) than in strain 2066 (17 and 59, respectively). The increase of the inbreeding coefficient is higher in strain 2066 than in strain 1077 (27 and 21%, respectively, at generation 20). The mean standard deviation of the individual inbreeding coefficients per generation is low (less than 4%) in both strains. Short-term inbreeding is stable over generations. The observed inbreeding effective size Ne _f and the observed familial structure effective size Ne _h converge to the same value. The number of founder genomes still present in the genetic pool of the generation decreases regularly: from 5.6 to 2.4 between G6 and G20 for strain 1077. It is a bit lower over time for strain 2066 (from 5.7 to 1.9 between G6 and G20). The effective number of founders is nearly twice as small as the total number: 30 for strain 1077 and 15 for strain 2066. The effective number of major ancestors decreases slightly in strain 1077 (13.6 in G6 and 12.9 in G20) and regularly in strain 2066 (13.8 in G6 and 9.4 in G20).