Investigating the effect of Azospirillum brasilense and Rhizobium pisi on agronomic traits of wheat (Triticum aestivum L.)

ABSTRACT

Plant growth-promoting rhizobacteria (PGPR) play an important role in improving crop growth but have not been studied sufficiently. A wire house experiment was conducted in Pakistan to determine the combined effect of inoculating wheat seeds with PGPR on the subsequent growth and yield of the wheat. The experiment included four treatments: T_{0 –} no-inoculation (control), T₁ – Azospirillum brasilense inoculation, T₂ – Rhizobium pisi inoculation and T₃ – co-inoculation with A. brasilense and R. pisi. Development and growth attributes, as well as final yield of wheat, were studied. Co-inoculation of seeds with both strains increased significantly wheat grain yield, the number of grains per plant and 1000-grain weight by 36%, 11% and 17%, respectively, compared to non-inoculated control. While crop growth rate increased for, respectively, 5.5% and 33% at tillering and flag leaf stages, corresponding values for T₃ were about 9% and 14% higher than values for sole inoculations in T₁ and T₂. Co-inoculation also significantly increased leaf epicuticular wax and relative water content as compared to the control treatment. Thus, inoculation of wheat seeds with A. brasilense and R. pisi and their combination is a promising method to improve growth, yield and quality of wheat.     

Biological Activities and Chemical Composition of Methanolic Extracts of Selected Autochthonous Microalgae Strains from the Red Sea

Four lipid-rich microalgal species from the Red Sea belonging to three different genera (Nannochloris, Picochlorum and Desmochloris), previously isolated as novel biodiesel feedstocks, were bioprospected for high-value, bioactive molecules. Methanol extracts were thus prepared from freeze-dried biomass and screened for different biological activities. Nannochloris sp. SBL1 and Desmochloris sp. SBL3 had the highest radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl, and the best copper and iron chelating activities. All species had potent butyrylcholinesterase inhibitory activity (>50%) and mildly inhibited tyrosinase. Picochlorum sp. SBL2 and Nannochloris sp. SBL4 extracts significantly reduced the viability of tumoral (HepG2 and HeLa) cells with lower toxicity against the non-tumoral murine stromal (S17) cells. Nannochloris sp. SBL1 significantly reduced the viability of Leishmania infantum down to 62% (250 µg/mL). Picochlorum sp. SBL2 had the highest total phenolic content, the major phenolic compounds identified being salicylic, coumaric and gallic acids. Neoxanthin, violaxanthin, zeaxanthin, lutein and β-carotene were identified in the extracts of all strains, while canthaxanthin was only identified in Picochlorum sp. SBL2. Taken together, these results strongly suggest that the microalgae included in this work could be used as sources of added-value products that could be used to upgrade the final biomass value.     

The association of cattle husbandry practices, environmental factors and farmer characteristics with the occurence of chronic bovine tuberculosis in dairy herds in the Republic of Ireland

A matched case-control study was undertaken to provide information on the role of farm management practices, environmental factors and farmer characteristics in the epidemiology of bovine tuberculosis. Eighty dairy herds with chronic tuberculosis were compared with the same number of herds which had been free of the disease for many years. A standardized questionnaire was used to obtain information from the farmers. the study was conducted from August to October 1990, in Counties Cork and Kilkenny, Republic of Ireland.

Factors which were identified as possibly contributing to recurrent outbreaks of tuberculosis outbreaks included nutritional factors, cattle purchases (especially bulls), the presence of badgers, and the spreading of slurry. Overall, the findings suggested that intensively managed dairy herds were at greater risk of bovine tuberculosis outbreaks than were other herds.

The study did not support some of the hypotheses which traditionally have been put forward as contributing to tuberculosis outbreaks. These included contact with neigboring cattle owing to movements to and from fragments or poor boundary fencing, presence of sub-standard cattle housing, movement of equipment or vehicles onto farms, and exposure to water supplies from rivers or streams. In the light of these findings, and in view of the lack of evidence in the scientific literature to support these hypotheses, we suggest that a general re-evaluation of their role in chronic tuberculosis is needed.     

COMPARISON OF THE RESISTIVE INDEX TO CLINICAL PARAMETERS IN DOGS WITH RENAL DISEASE

The resistive index (RI) is a measurement of arteriole vascular resistance and is obtained by pulsed-wave Doppler interrogation. The diagnostic potential of the renal resistive index (RI) was retrospectively investigated in 142 kidneys from 81 dogs. The resistive index of each kidney was compared to clinical laboratory parameters, clinical diagnoses, and sonographic findings. The mean renal resistive index (RI) for 22 normal kidneys was 0.61 (standard deviation = 0.06). An elevation in the mean renal RI (>0.70) was found for the clinical diagnoses of acute renal failure and congenital dysplasia. When a RI of greater than 0.70 was considered abnormal, the sensitivity and specificity of the RI in determining normal vs, abnormal kidneys were 38% and 96% respectively.     

Cardiopulmonary effects of thoracoscopy in anesthetized normal dogs

Objective To evaluate the effect of an open‐chest condition on oxygen delivery in anesthetized dogs. Study design Prospective, controlled experimental study. Animals Eight clinically normal adult Walker Hound dogs weighing 25.6–29.2 kg. Methods Eight anesthetized dogs underwent an open‐chest operation after the insertion of thoracoscopy cannulae in the lateral chest walls . A Swan Ganz catheter was used to both measure hemodynamic parameters and obtain mixed venous blood samples for blood gas analysis. A dorsal pedal catheter was placed to both measure arterial blood pressure and obtain blood samples for blood gas analysis. Oxygen delivery index and oxygen extraction ratio were calculated. A randomized block anova for repeated measures was used to evaluate the effect of the treatment on hemodynamic and pulmonary parameters. Results Creation of an open chest did not significantly affect oxygen delivery index (DO₂I; p = 0.545). It induced a significant decrease in arterial oxygen partial pressure (PaO₂; p = 0.018) and arterial oxygen content (CaO₂; p = 0.025). It induced a significant increase in shunt fraction (p = 0.023), physiologic dead space (p = 0.015), and alveolar‐arterial oxygen difference (p = 0.019). Arterial partial pressure of carbon dioxide (PaCO₂; p = 0.766) and arterial hemoglobin oxygen saturation (SaO₂; p = 0.178) were not significantly affected. Diastolic (DPAP; p = 0.050) and mean (MPAP; p = 0.033) pulmonary arterial pressures were significantly increased by opening the chest. Other hemodynamic parameters were not significantly affected. Conclusions Opening the thoracic cavity is not detrimental to hemodynamic function and oxygen delivery in normal dogs, although impaired gas exchange does occur. Clinical relevance Close monitoring of patients is recommended during open‐chest thoracoscopy as adverse effects on gas exchange can contribute to hypoxemia.     

Strategies for two-stage sampling designs for estimating herd-level prevalence

We propose a herd-level sample-size formula based on a common adjustment for prevalence estimates when diagnostic tests are imperfect. The formula depends on estimates of herd-level sensitivity and specificity. With Monte Carlo simulations, we explored the effects of different intracluster correlations on herd-level sensitivity and specificity. At low prevalence (e.g. 1% of animals infected), herd-level sensitivity increased with increasing intracluster correlation and many herds were classified as positive based only on false-positive test results. Herd-level sensitivity was less affected at higher prevalence (e.g. 20% of animals infected). A real-life example was developed for estimating ovine progressive pneumonia prevalence in sheep. The approach allows researchers to balance the number of herds and the total number of animals sampled by manipulating herd-level test characteristics (such as the number of animals sampled within a herd).     

Controlling emerging diseases in the 21st century

The presentation addressed the following points: the role of veterinary epidemiology in emerging and global disease outbreaks; the contribution of veterinary epidemiology discipline to understanding and prevention of infections and other emerging animal disease, and the challenges for the discipline of veterinary epidemiology in the near future. The emerging and re-emerging infections animal diseases have contributed to expand the outlook of veterinary epidemiology. Methods and approaches in this discipline have been modified to satisfy the needs of society and of the scientific community. Mistakes and "bad turns" were made and should be avoided in the future. Veterinary epidemiology is alive and growing.