Survival of south african strains of biovar 2 and biovar 3 ofPseudomonas solanacearum in the roots and stems of weeds

Summary South African strains of biovar 2 and biovar 3 ofPseudomonas solanacearum were compared for their ability to survive in the roots and stems of ten weed species. After artificial inoculation with a biovar 2 strain none of the weed species developed wilt symptoms, but the pathogen was isolated from one species,Physalis angulata L. Using inoculum of a biovar 3 strain, two of the weed species developed wilt symptoms (Datura stramonium L.,Solanum nigrum L.), and the pathogen was isolated from four species,Eragrostis curvula, Amaranthus hybridus L.,Datura stramonium L. andSolanum nigrum.     

Failure to respond to endogenous or exogenous melatonin may cause nonphotoresponsiveness in Harlan Sprague Dawley rats

Background  

Responsiveness to changing photoperiods from summer to winter seasons is an important but variable physiological trait in most temperate-zone mammals. Variation may be due to disorders of melatonin secretion or excretion, or to differences in physiological responses to similar patterns of melatonin secretion and excretion. One potential cause of nonphotoresponsiveness is a failure to secrete or metabolize melatonin in a pattern that reflects photoperiod length.     

Improvement of phosphorus uptake, phosphorus use efficiency, and grain yield of upland rice (Oryza sativa L.) in response to phosphate-solubilizing bacteria blended with phosphorus fertilizer

Phosphorus (P) limitation in soil is a major concern for crop productivity. However, the use of chemical fertilizer is hazardous to the environment and costly. Therefore, the use of phosphate-solubilizing bacteria (PSB) is an eco-friendly approach for a sustainable agricultural system. In the present study, a field trial was conducted for two consecutive years to study the effects of three PSB strains isolated, Bacillus licheniformis, Pantoea dispersa, and Staphylococcus sp., with different P fertilizer rates on P uptake, P use efficiency (PUE), and grain yield of rice. The activities of soil enzymes were also studied in relation to PSB treatments. Comparative analysis of the yield and biochemical parameters revealed that inoculation of PSB consortium could reduce almost 50% of the recommended P dose in rice cultivation. Three PSB strains in combination with 50% P dose was most effective and showed the highest increases in P uptake and PUE as compared to the uninoculated control. Moreover, the PSB consortium combined with 50% P dose contributed to 50.58% and 35.64% yield increases compared to the uninoculated control for 2018 and 2019, respectively. Significant increases in the activities of soil dehydrogenase, alkaline phosphatase, and acid phosphatase were also recorded under PSB treatment.     

Acute phase protein changes in calves during an outbreak of respiratory disease caused by bovine respiratory syncytial virus

Bovine acute phase proteins (APPs), lipopolysaccharide binding protein (LBP), serum amyloid A (SAA), haptoglobin (Hp) and alpha₁-acid glycoprotein (AGP) were evaluated as inflammatory markers during an outbreak of bovine respiratory disease (BRD) caused by bovine respiratory syncytial virus (BRSV). Calves (n = 10) presented mild to moderate signs of respiratory disease. Secondary bacterial infections, Pasteurella multocida and Mycoplasma dispar as major species, were detected in tracheobronchial lavage samples. Concentrations of SAA and LBP increased at week 1 had the highest values at week 3 and decreased at week 4 of outbreak. Some calves had high Hp concentrations at week 3, but AGP concentrations did not rise during respiratory disease. Higher SAA, LBP and Hp concentrations at a later stage of BRD (week 3) were associated with the low BRSV-specific IgG₁ production, suggesting that these calves had enhanced inflammatory response to the secondary bacterial infection. In conclusion, APPs (especially SAA and LBP) are sensitive markers of respiratory infection, and they may be useful to explore host response to the respiratory infections in clinical research.     

Mycobacterium tuberculosis infections in eight species at the National Zoological Gardens of South Africa, 1991-2001.

Between 1991 and 2001 a total of 12 cases of Mycobacterium tuberculosis infection in eight different species were recorded in the National Zoological Gardens of South Africa in Pretoria (Tshwane). The genetic relatedness between seven of the M. tuberculosis isolates was determined by IS6110 restriction fragment length polymorphism analysis. For the majority of isolates that were analyzed, a high degree of polymorphism suggested different sources of infection. Evidence of M. tuberculosis transmission between animals is reported in two chimpanzees (Pan troglodytes) housed together, from which samples were collected for analysis 29 mo apart.     

Critical control points for avian influenza A H5N1 in live bird markets in low resource settings

Live bird markets can become contaminated with and become a source of transmission for avian influenza viruses including the highly pathogenic H5N1 strain. Many countries affected by the H5N1-virus have limited resources for programs in environmental health, sanitation and disease control in live bird markets. This study proposes five critical control points (CCPs) to reduce the risk of H5N1-virus contamination in markets in low resource settings. The CCPs were developed based on three surveys conducted in Indonesia: a cross-sectional survey in 119 markets, a knowledge, attitudes and practice survey in 3 markets and a microbiological survey in 83 markets. These surveys assessed poultry workflow, market infrastructure, hygiene and regulatory practices and microbiological contamination with the H5N1-virus. The five CCPs identified were (1) reducing risk of receiving infected birds into the market, (2) reducing the risk of virus spread between different bird flocks in holding cages, (3) reducing surface contamination by isolating slaughter processes from other poultry-related processes, (4) minimizing the potential for contamination during evisceration of carcasses and (5) reducing the risk of surface contamination in the sale zone of the market. To be relevant for low resource settings, the CCPs do not necessitate large infrastructure changes. The CCPs are suited for markets that slaughter poultry and have capacity for daily disposal and removal of solid waste from the market. However, it is envisaged that the CCPs can be adapted for the development of risk-based programs in various settings.     

Effect of in-water iodine supplementation on weight gain, diarrhea and oral and dental health of nursery pigs

A farm trial was conducted to evaluate the effect of in-water iodine on piglet growth, the incidence of diarrhea, and the development of deleterious oral and dental conditions. A total of 208 weaned piglets were included in the study. Piglets were weighed 3 times: within 24 h of weaning, and 3 wk and 6 wk after weaning. A concentration of 1 ppm iodine was provided in their drinking water. Swabs were taken from all water nipples and water lines and pooled fecal samples were collected from all pen floors. Fecal samples were also collected from sows at weaning. The swabs and fecal samples were tested for the presence of Salmonella and Escherichia coli. Within 24 h of each weighing, a complete oral examination was performed on each piglet. No significant difference in growth (P > 0.05) or dental conditions (P > 0.05) was found among treatment groups during the period that iodine was added to the drinking water. After weaning, all deleterious oral conditions increased (oral lesions from weaning to 6 wk, staining and caries from weaning to 3 wk, gingivitis from 3 wk to 6 wk; P < 0.05). Only gingivitis was found to be negatively associated with piglet weight (P < 0.05). Salmonella was cultured only twice from fecal samples and never from water nipples. Only 1 sow tested positive for Salmonella and E. coli O139: K82 and O157:K"V17 were cultured only rarely from the water nipples. No signs of diarrhea were noted throughout the study. Adding an aqueous iodine supplement to nursery pigs, therefore, did not provide an advantage for either growth or oral condition. Deleterious oral conditions do increase after weaning, with gingivitis being associated with lower piglet weight.     

A study of chemical characteristics of soil in relation to street trees status in Riga (Latvia)

The chemical composition of soil and appropriate supply of nutrients are very important factors for normal plant growth and development. Lime tree (Tilia x vulgaris H.), is a popular tree species used for urban landscaping in Europe. However, there is little information on the chemical element concentrations available to and recommended for T. x vulgaris in urban soils. The objectives of this study were: (1) to investigate the amount of nutrients, de-icing salts and heavy metals available for uptake by trees in the city centre on a seasonal scale; and (2) to assess the relationship between the vitality of T. x vulgaris and soil chemistry. The research was carried out in five streets and a park in Riga (Latvia) during 2005–2007. Plant-available concentrations of 17 nutrients and heavy metals were determined via 1 M HCl extraction. Soil Cl content, pH, and electrical conductivity were also measured.The investigation revealed a high heterogeneity in soil chemical composition. In total, the element concentrations in urban soils did not exceed values commonly found in urban environments. Higher concentrations of Na, Cl, Ca, Mg, Zn, Cu, and increased pH, but lower P and B concentrations were found in the street soils in comparison to the park soil. Significantly higher concentrations of Na, Cl, and Mg, and lower concentrations of K, Fe, Cu, and B, as well as unfavourable ratios of several element concentrations were found in the soils where more damaged street trees were growing. In addition, the recommended fertilization regimes are discussed.