Chemical composition and biological activity of Salvia officinalis L. essential oil against Aphis fabae Scopoli (Hemiptera: Aphididae)

Journal of Plant Diseases and Protection - This study investigated chemical composition, repellent and biocidal activities of Salvia officinalis essential oil against Aphis fabae. In total, 19...     

Owner survey of schitosomiasis mortality in sudanese cattle

The estimated mortality in six- to 30-month-old cattle due to presumptive schistosomiasis was 7.1% for 155 interviews conducted in the White Nile Province in 1981. This mortality was higher for those herds under sedentary management than for migratory herds (9.4% vs 3.6%). The interviews were done through an informal visit technique by a veterinarian living in the area. The approximate number (19,000) of cattle over six months old estimated to be owned by those interviewed represents about 1% of the population in that province. The mortality from all causes in the six- to 30-month age group was 9.2%; in the over 30-month age group it was 1.8%. The authors judge the schistosomiasis mortality to be somewhat upwardly biased but the mortality due to all causes (9.2%) is consistent with the few reports available.     

Antigenic relatedness of pigeon herpes encephalomyelitis virus to other avian herpesviruses

Pigeon herpes encephalomyelitis virus (PHEV) was compared with seven avian herpesviruses for antigenic relatedness using monospecific antisera and the indirect fluorescent-antibody (IFA), agar-gel-immunodiffusion, and serum-neutralization tests. No antigenic relationship was detected between PHEV and Marek's disease virus, turkey herpesvirus, infectious laryngotracheitis virus, and duck enteritis virus. A common precipitating antigen was detected between the PHEV and pigeon herpesvirus (PHV), owl herpesvirus (OHV), and falcon herpesvirus (FHV). These four viruses also cross-reacted in the IFA test. Weak neutralizing activity was detected only between PHV antiserum and PHEV. These results suggest that the PHEV should be classified as a herpesvirus related to, but distinct from, the PHV-OHV-FHV group of viruses with which it shares common antigens.     

Antibioisis and antixenosis resistance to Dactylopius opuntiae (Hemiptera: Dactylopiidae) in Moroccan cactus germplasm

Phytoparasitica - The wild cochineal, Dactylopius opuntiae (Cockerell), has become the main pest of the prickly pear [(Opuntia ficus-indica (L.) Miller] cactus crop in most of the Mediterranean...     

Economic evaluation of the production impact of bovine schistosomiasis and vaccination in the Sudan

This study was done to evaluate the estimated economic consequences of the recent discovery that an irradiated Schistosoma bovis vaccine was effective in reducing mortality and intensity of infection in cattle after field exposure to S. bovis in the White Nile province. The benefits and costs were hypothesized to occur over a 5-year period starting after the vaccine had been further developed to optimal commercial usefulness.

The potential benefits of vaccination are from the avoidance of mortality and growth delay losses caused by S. bovis infection and were based on an owner survey conducted in 1981. These benefits were discounted from the time of their potential marketing opportunity to the first year of a vaccination program at 15% per annum and were valued on a basis of 1982 prices for live cattle exported to Egypt and Saudi Arabia. Variations in benefits stem from degree of infection probability, mortality and morbidity estimates and percent of animals vaccinated. Since clinical schistosomiasis (“gorag” — sunken-eyed appearance) and associated production losses occur almost exclusively in 6- to 30-month-old cattle, and there is evidence for long-term immunity, vaccinations would be given to cattle in this age-specific group or younger once in their lifetime. The principal variation in vaccination program costs, also valued at 1982 prices, is from vaccine production costs; $0.50 or $4.00 per dose. A vaccine efficacy of 70%, observed in a previously reported field trial, was used in these calculations.

Present value benefit—cost (b–c) ratios were estimated for the central, western and southern areas for high- and low-level effects of S. bovis impact on production and the vaccination program, cost and effectiveness. In an area (central provinces) of high infection probability (90%), high percentage of animals vaccinated (90%), high mortality (7.1%), and low vaccine production costs, the b–c ratio was 12.7. In contrast, a b–c ratio of 0.7 was estimated for an area (southern provinces) assuming low infection probability (50%), low percent of animals vaccinated (50%), lower mortality (3.55%) and high vaccine production costs. Potential returns from increased future milk and calf production and from faster herd build-up with younger females were not included in these benefit calculations. These results indicate that under most conditions further development of the vaccine and cost-effective vaccine production techniques would yield very favorable returns from improved livestock production efficiency in the Sudan. Export prices were assumed to not vary significantly with increased supply of export-quality cattle resulting from the estimated production losses avoided by vaccination against schistosomiasis.     

Evaluation of Pasteurella multocida isolated from rabbits by capsular typing, somatic serotyping, and restriction endonuclease analysis.

The goal of this study was to characterize Pasteurella multocida isolated from rabbits. Five hundred and fifty-three apparently healthy rabbits were sampled for this study. Nasal swabs were collected from each rabbit for P. multocida isolation and identification. Isolates were further characterized by capsular and somatic antigens and genomic DNA fingerprinting. Thirty-nine P. multocida isolates were recovered from 553 rabbits (7%). Capsular typing was done by depolymerization of P. multocida capsule by Staphylococcus aureus hyaluronidase and by disc diffusion with mucopolysaccharidase enzymes (heparinase III, chondroitinase AC, and hyaluronidase). Thirty-one (79%) of the isolates were capsular type A, and 8 isolates (21%) had untypable (UT) capsules. The gel-diffusion precipitin test was used to determine the somatic type of P. multocida isolates. Nineteen isolates were somatic serotype 3 (49%), 12 were serotype 1 (31%), 1 was serotype 2, 2 were serotype 5, 2 were serotype 12 with a weak reaction to antiserum raised against serotype 7 (5%), and 1 was serotype 4. Two of the isolates (5%) were UT. Restriction endonuclease analysis of the DNA of the isolates revealed 7 distinct profiles by digestion with HindIII, and 12 profiles were obtained with HpaII, whereas digestion with EcoRI did not differentiate between any of the P. multocida DNA isolates studied. The DNA restriction endonuclease enzyme HpaII was found more useful for differentiating between DNA fingerprints of P. multocida rabbit isolates. However, no correlation between capsular type, somatic serotypes, and DNA fingerprints was seen in this study.     

Clinical diagnosis of schistosomiasis in sudanese cattle

This study was done in the White Nile Province to characterise the history and signs of naturally occurring Schistosoma bovis infection in cattle (Gorag). Necropsy and laboratory examinations were performed on 10 animals six to 30 months of age which were in poor condition. They were selected because of a history suggestive of schistosomiasis. All the animals showed some degree of S. bovis infection; eight had a moderate or heavy degree of infection. Also all had liver damage due to either past or active Fasciola gigantica infection. Although concurrent infection with these two trematodes is common an owner who diagnoses Gorag is most likely referring to the syndrome caused by S. bovis as being the major cause of the poor performance observed. Fasciolicide treatment may eliminate active fascioliasis as the principal damaging agent. Also differentiating signs of haemorrhagic diarrhoea, severely sunken eyed appearance and only moderate inappetence are common in animals with acute schistosomiasis.     

番茄黄色柱头突变体ys的表型与遗传规律分析

通过EMS诱变获得了1个可稳定遗传的番茄黄色柱头突变体,命名为ys(yellow stigma)。色素含量测定发现:同野生型相比,突变体ys柱头中的叶绿素和类胡萝卜素含量没有明显变化,但对香豆酸和柚皮素查尔酮含量显著高于野生型,推测呈黄色的柚皮素查尔酮的大量积累可能在黄色柱头形成过程中起着重要作用。此外,分析发现,突变体和野生型在柱头表面结构、柱头可授性及花粉活力方面没有显著差异。对突变体ys与野生型构建的F_1、F_2、BC_1以及BC_2群体的遗传分析发现,F_1和BC_2均为绿色柱头植株,F_2和BC_1群体绿色柱头植株与黄色柱头植株的比例符合3∶1和1∶1的分离比(P0.05),表明黄色柱头突变受1对隐性基因控制,其遗传方式符合孟德尔遗传定律。