A screening test for Mycosphaerella brassicicola on Brassica oleracea

A greenhouse screening method for resistance to ringspot (Mycosphaerella brassicicola) inBrassica oleracea is described. High infection levels were achieved by spraying young plants by mycelial inoculum enriched with 3% sucrose. The screening method was tested on three Brussels sprouts, three cabbage and three cauliflower cultivars, with known reactions to ringspot in the field. Resistance was expressed both in cotyledons and true leaves by a lower number of lesions than the susceptible control and/or by hypersensitive reactions. Results of the seedling tests reflected differences in resistance in the field. Under controlled conditions the new test can be applied year-round to young plants, thus accelerating selection procedures.     

Inheritance of fenvalerate and carbofuran resistance in colorado beetles—Leptinotarsa decemlineata (Say)—from North Carolina

Progeny from reciprocal F1 crosses and F1 backcrosses between fenvalerate-resistant and fenvalerate-susceptible Colorado beetles, Leptinotarsa decemlineata (Say), and between carbofuran-resistant and carbofuran-susceptible Colorado beetles were bioassayed to investigate the mode of inheritance of resistance to these chemicals. Bioassays of progeny from these crosses indicate that resistance to fenvalerate is inherited in a semi-recessive, sex-linked manner and carbofuran resistance is inherited in a partially dominant autosomal fashion. Log concentration/probit mortality lines and chi-square tests, however, indicate that multiple genes may be involved in resistance to both insecticides.     

Metabolism of [ring-2,6-14]parathion in plant cell suspension cultures of carrot (Daucus carota), purple foxglove (Digitalis purpurea), soybean,thorn apple (Datura stramonium) and wheat (Triticum aestivum)

By means of standardized procedures, the metabolism of [ring-2,6-¹⁴C]-parathion was investigated in carrot (Daucus carota L.), purple foxglove (Digitalis purpurea L.), soybean (Glycine max Merrill cv. ?Mandarin’?, and Glycine max Merrill cv. ?Harosoy 63’? cultivated on B5 and Miller media, respectively), thorn apple (Datura stramonium L.), and wheat (Triticum aestivum L.) cell suspension cultures. In the wheat and soybean (Mandarin) cells only 2.9 and 8.9%, respectively, of the applied parthion remained unmetabolized after 48 h of incubation, while 51.2, 57.9, 60.3, and 62.4% of the unchanged parent were detected in the D. purpurea, D. Stramonium, carrot and soybean (Harosoy) cultures, respectively. In all suspensions, paraoxon and 4-nitrophenol were found as phase I metabolites, thus demonstrating that plant tissues can catalyse oxidative desulfuration and dearylation of parathion. 4-Nitrophenol was also glycosylated with glucose and possibly galactose. Further, as yet unidentified, metabolites indicated that bio-transformations had also occurred at the aromatic moiety. Large amounts of non-extractable residues were detected in the wheat suspension (38.3%), while the other cultures showed a lower incorporation of ¹⁴C into insoluble cell material (0.9-9.4%). For a prospective ecotoxicological evaluation of the metabolic fate of pesticides and xenobiotics in plants in general, the differential metabolic capacity of plant cell cultures and plants should be taken into account.     

Evaluation of peritoneal fluid pH, glucose concentration, and lactate dehydrogenase activity for detection of septic peritonitis in horses

OBJECTIVE: To determine whether peritoneal fluid pH, glucose concentration, and lactate dehydrogenase activity can be used to differentiate horses with septic peritonitis from those with nonseptic peritonitis. DESIGN: Prospective study. ANIMALS: 46 horses, including 10 healthy horses, 15 horses with septic peritonitis, and 21 horses with nonseptic peritonitis. PROCEDURE: Peritoneal fluid and blood samples were analyzed for pH, glucose concentration, and lactate dehydrogenase activity. Complete blood cell counts were performed, and peritoneal fluid samples were submitted for bacterial culture. RESULTS: Horses with septic peritonitis had significantly lower peritoneal fluid pH and glucose concentrations than horses with nonseptic peritonitis and healthy horses. Compared with other tests, serum-to-peritoneal fluid glucose concentration differences > 50 mg/dl had the highest diagnostic use for detection of septic peritonitis. Peritoneal fluid pH < 7.3, glucose concentration < 30 mg/dl, and fibrinogen concentration > 200 mg/dl were also highly indicative of septic peritonitis. CLINICAL IMPLICATIONS: Peritoneal fluid pH and glucose concentration can be used to assist in the identification of horses with septic peritonitis. These measurements can provide an early indication of sepsis, especially if cytologic evaluation of peritoneal fluid is unavailable or results are equivocal and peritoneal fluid bacterial culture results are pending.     

Neurotoxicity in calves induced by the plant, Nierembergia hippomanica Miers var. violacea Millán in South Africa

The plant Nierembergia hippomanica var. violacea has been incriminated in field outbreaks of neurotoxicity in calves in the Free State Province. Hepatotoxicity and electrocardiogram (ECG) deviations were induced in a sheep dosed with 5 g/kg dried plant material on four consecutive days. A calf dosed with 2.5 g/kg dried plant material, on two consecutive days, did not show overt clinical changes. Voluntary ingestion of approximately 30 g/kg fresh flowering plants by a second calf resulted in nervous signs characterized by chewing motions, protrusion of the tongue, dysphagia, hypermetria, ataxia, paresis and lateral recumbency. Salivation, dehydration and cardiac irregularities completed the clinical picture. Clinical chemistry changes revealed muscle damage and increased serum urea and creatinine concentrations indicative of kidney involvement. This is the first confirmed outbreak of Nierembergia hippomanica var. violacea intoxication of stock in South Africa.     

Litter Size and Vagina–cervix Catheter Penetration Length in Gilts

As in other species, the reproductive tract in pigs increases in size with age and body weight, and the development of the reproductive tract depends on a balance between development of the pituitary–ovarian axis and the influence of metabolic hormones. Two experiments were conducted in prepubertal Duroc gilts, 150–180 days of age, to determine whether litter size is related to vaginal–cervix catheter penetration length during insemination. In experiment 1, oestrus was induced in 452 gilts with a combined dose of 400 IU Pregnant Mare Serum Gonadotrophine (PMSG) + 200 IU human chorionic gonadotropin (hCG). The gilts were classified into three catheter penetration length groups: Ih, ≤ 21 cm; IIh, > 21 and < 28 cm; IIIh, > 28 cm. The litter size was lowest in group Ih (7.35 ± 0.15) compared with groups IIh (7.81 ± 0.12; p < 0.05) and IIIh (10.0 ± 0.36; p < 0.001). In experiment 2, first oestrus was induced in 162 gilts by boar exposure. The gilts were classified into three catheter penetration length groups at insemination during their second oestrus: In, ≤ 24 cm; IIn, > 24 and < 26 cm; IIIn, > 26 cm. As in experiment 1, the litter size was lowest in the group with the shortest catheter penetration length (8.32 ± 0.19). The litter size was not different among gilts of groups IIn and IIIn (8.84 ± 0.35 and 9.56 ± 0.46, respectively), but litter size was lower (p < 0.05) in group In than in group IIn. Based on the combined data from both experiments, the correlation between the catheter penetration length and total number of piglets born was expressed as: y=5.346 ± 0.104x; r=0.361 (p < 0.05). Fertility rate was not different among the groups of gilts induced into oestrus by hormone treatment or inseminated in the second oestrus; however, the total fertility rate of boar‐exposed gilts was higher (p < 0.0001) than PMSG/hCG treated animals. Thus, it is possible to conclude that litter size at first farrowing is associated with vaginal–cervix catheter penetration length during insemination of the gilt.     

In utero transmission of bovine leukemia virus

In an initial study, 18 calves born to cows persistently infected with bovine leukemia virus (BLV) were tested for infective virus and antibodies at birth, and no infected or seropositive animals were found. Four of these calves were maintained in quarters where infected animals were housed, and 3 of the 4 subsequently became infected. These were probably contact infections acquired during, or at some time after, birth. The remaining 14 calves were kept in isolation pens in a building housing no infected cattle. None of this group was found to be BLV infected during 1 year of observation. In further studies, 15 pregnant cows inoculated with BLV became infected. One abortion, considered to be unrelated to the BLV inoculation, occurred 38 days later. The remaining 14 cows gave birth to 1 dead and 14 live calves. The dead calf and its live twin were seropositive for BLV at birth, indicating that they had been infected in utero. The remaining 13 calves were negative for BLV antibodies at birth and remained so during 1 year of observation.