Bradyrhizobium sp. (Lupinus) in the winter rainfall region of South Africa

Widespread cultivation of lupin has resulted in the establishment of effective populations of Bradyrhizobium sp. (Lupinus) in the winter rainfall region of the Western Cape, South Africa. To determine whether inoculation increased yields of Lupinus angustifolius L., field trials were carried out at five sites in this region. Populations ranged from 380 rhizobia g^-1 in a moderately alkaline (pH 7.6) soil to >5,000 rhizobia g^-1 in four moderately acid (pH 5.5-5.8) soils. Soil isolates were generally similar to the inoculant strain WU425 in nitrogen-fixing effectiveness but several were significantly less effective. Average effectiveness of isolates from certain soils differed significantly. Although inoculation failed to appreciably increase nodule occupancy by WU425 in acid soils containing high populations of rhizobia, nodule occupancy was increased to 98% in the low population alkaline soil. The latter site was later abandoned because of disease. At the other sites, analysis of seed dry mass and protein content showed that yields were not significantly increased by either inoculation, nitrogen fertiliser (45 kg N ha^-1) or molybdenum applications. Analysis of genomic DNA by PCR fingerprinting showed that WU425 (isolated in Western Australia) and serologically related strains from other cultures clustered separately from the soil isolates. Isolates from the four acid soils were genomically diverse, whereas isolates from the alkaline soil formed a homogeneous cluster. Further investigation is required to determine the benefit of inoculation in alkaline soils of the winter rainfall region of the Western Cape.     

Symbiotic and genomic diversity of ‘cowpea’ bradyrhizobia from soils in Botswana and South Africa

Strain CB756 is usually an effective competitor against indigenous bradyrhizobia for nodulation of peanut in South Africa. Recently, inoculation of peanut and cowpea with CB756 in loamy sand soils of Botswana or a sandy clay loam in South Africa proved unsuccessful, achieving <2% nodule occupancy. A survey of ‘cowpea’ bradyrhizobia from five soils in Botswana and one in South Africa showed that many were effective in ability to fix N₂ on peanut and cowpea. However, 15 isolates from Good Hope, Botswana were all effective on cowpea but ineffective on peanut, three failing to nodulate the latter. Selected cowpea isolates were significantly more competitive than CB756 for nodulation of cowpea in Leonard jars, but four were unsuccessful when inoculated at Roodeplaat, South Africa. When strain CB756 and two isolates were inoculated in pots containing Roodeplaat soil, at a 4:1 inoculant to soil bradyrhizobia ratio, their average nodule occupancy was 8% on cowpea compared to 40% on peanut. Significant differences in strain nodule occupancy were not detected on either cowpea or peanut. In contrast, nodule occupancy in loamy sand from Good Hope, Botswana, inoculated at a 40:1 inoculant to soil bradyrhizobia ratio, was 22.4% on cowpea and only 6.8% on peanut. In Good Hope soil, strain CB756 was the weakest competitor on cowpea but strain differences were insignificant on peanut. Whereas the Good Hope soil population was effective on cowpea, it was ineffective on peanut. DNA fingerprinting showed that isolates from Gaborone, Francistown and Roodeplaat contained several different genotypes, whereas those from Good Hope, Rasesa and Maun were more homogeneous. The dominance at Good Hope of genotypes effective on cowpea but ineffective on peanut emphasises the value of assessing the symbiotic capabilities and structures of indigenous populations.     

Einfluß von Sorte und Phosphordüngung auf den Phosphorgehalt und die Aktivität der sauren Phosphatasen von Weizen und Gerste. — Ein Beitrag zur Diagnose der P-Versorgung von Pflanzen —

Influence of cultivar and phosphorus application on P concentration and acid phosphatase activity in wheat and barley. — A contribution to the diagnosis of P supply of plants — Acid phosphatase activity compared to total P concentration was studied as a diagnostic criterion of the phosphorus nutritional status of wheat and barley. In a field experiment with wheat cv ‘Sperber’ the influence of P level on P_ase activity and P concentration was monitored at four developmental stages. Significant correlations with grain yield were found for P_ase activity at all four stages whereas P concentration was significantly correlated with grain yield in the early stage (DC 26–27) only. Genetic variability and influence of P supply on P_ase activity and P concentration was studied at low and at high P supply with 9 wheat and 23 barley cultivars grown for 4 and 5 weeks in pot experiments. The variability of P_ase activity caused by cultivars was higher than that caused by P supply. It is, therefore, concluded that the acid phosphatase activity is not suitable as a generally applicable tool for diagnosing P supply. In comparison, total P concentration of the plants was influenced to a higher degree by P supply than by cultivars. Total P is, therefore, more suitable as a criterion for diagnosing P supply of plants than P_ase activity. The samples, though, have to be collected in stages before DC 27.     

Phosphate sorption by Egyptian,Ethiopian and German soils and P uptake by rye (Secale cereale L.) seedlings

Phosphate sorption was studied in samples (0 - 20 cm depth) of five soils from Egypt (pH 7.4 - 8.7), four soils from Ethiopia (pH 3.9 - 5.3) and six soils from Germany (pH 3.3 - 7.2). Sorption parameters were calculated according to Pagel and Van Huay (1976) and according to Langmuir (Syers et al., 1973). Phosphate sorption parameters and oxalate extractable Fe and Al (Fe_ox, Al_ox) were related to the phosphate uptake by young rye plants in Neubauer pot experiments. P sorption parameter after Pagel and Van Huay (A) correlated significantly positively with the Fe_ox and Al_ox content in acid (r = 0.73) as well as in calcareous soils (r = 0.89) if the whole equilibrium concentration range (0 - 14 mg P/L) was considered. The relations calculated after Langmuir (B) were similar. P uptake by rye in acid soils was negatively correlated with the affinity constant n (r = ?0.76, (A)). In calcareous soils, a negative correlation between P uptake and affinity constant was calculated in the lower P equilibrium range (0 - 2.8 mg P/L) only for (B). Thus, P uptake decreased with increasing strength of P bonding to soil. From these results it is concluded that phosphate sorbed to Fe/Al oxides is an important P source for plants in acid and calcareous soils.     

Role of the environment in the development of canine atopic dermatitis in Labrador and golden retrievers

Canine and human atopic dermatitis are multifaceted diseases whose clinical development may be influenced by several factors, such as genetic background, environment, secondary infections, food and psychological effects. The role of the environment has been extensively examined in humans but remains unclear in dogs. The aim of this study was to examine environmental factors in two genetically close breeds, Labrador and golden retrievers. Using standard criteria, atopic dogs in Switzerland and Germany were selected and compared with healthy individuals. Information on environmental factors was collected using a 46-question survey encompassing date and place of birth, way of life at the breeder's and owner's home, food and treatments. Univariate and multivariate logistic regression were used to assess the association between potential risk factors and disease status. The following parameters were associated with an increased risk of disease development: living in a shed during puppyhood, adoption at the age of 8-12 weeks and washing the dog regularly. In contrast, the following factors were associated with a lower risk: living in a rural environment, living in a household with other animals and walking in a forest. These associations do not prove causality but support the primary hypothesis that certain environmental factors may influence the development of canine atopic dermatitis. Further studies are warranted to confirm these results and conclusions.     

Fowl adenovirus (FAdV) serotype 4 causes depletion of B and T cells in lymphoid organs in specific pathogen-free chickens following experimental infection

In the present investigation flow cytometric analysis and immunohistochemistry were applied together for the first time to gain new insights into the interaction between virulent fowl adenoviruses (FAdV) and the immune system of chickens. As a model for virulent FAdV infections a FAdV-4 strain was used, known as the aetiological agent of Hepatitis-Hydropericardium syndrome (HHS) in broilers sometimes also named Angara Disease. Specified pathogen-free chickens (SPF) were divided into three different groups. Group I was infected at first day of life with an attenuated form of the virus obtained through continuous cell culture passage with the virulent virus and then re-infected 3 weeks later with the virulent progenitor virus. Group II was solely infected with the virulent virus at 3 weeks and group III served as a negative control. Following infection with the virulent virus a decrease of CD3+, CD4+ and CD8+ cells was noticed in the spleen. This was accompanied by a decrease of CD4+ and CD8+ T-lymphocytes in the thymus. Those birds infected with the attenuated virus in first instance and challenged with the virulent virus did not show these pathological effects in the thymus. In the bursa of Fabricius a severe depletion of lymphocytes was observed by immunohistochemistry in birds, infected with the virulent virus. Taken together it can be concluded that an infection with FAdV-4 has profound effects on cells, of the humoral and cell-mediated immune responses. The effects are much more severe in the birds infected with the virulent virus only indicating that the preceding infection with the attenuated virus reduces significantly the adverse effects induced by the virulent virus.     

Cache Valley virus: A scoping review of the global evidence

Cache Valley virus (CVV) is a mosquito‐borne RNA virus detected throughout North America, Central America and parts of South America. A limited number of human case reports have described severe illness. CVV infection has been associated with outbreaks of congenital defects in small ruminants in Canada and the United States. A scoping review was conducted to identify, characterize and summarize research on CVV, and to identify research gaps. A structured search was conducted in eight electronic databases, with additional search verification and grey literature investigation. All captured studies were independently appraised by two reviewers for relevance and data characterization. The review captured 143 relevant studies investigating CVV epidemiology (n = 104), pathogenesis (n = 37), viral characteristics (n = 24), transmission (n = 14), diagnostic test performance (n = 8) and mitigation strategies (n = 2). Evidence of CVV infection was found in mosquito studies (n = 47), and serological evidence of exposure was demonstrated in animals (n = 41), as well as human (n = 20) studies. In sheep, five outbreaks of birth defects following asymptomatic dam CVV infection during the first 50 days of pregnancy were reported. Only six human cases of CVV‐associated illness were captured, with case symptoms described as initially non‐specific, progressing to more severe clinical signs (e.g., meningitis). No research was identified investigating treatment, societal knowledge and risk perception, economic burden or predictive models related to the impact of climate change on CVV. CVV circulates in mosquito and animal species across a large area of the Americas. Small ruminants are the only animals in which CVV‐associated clinical disease has been extensively studied. It is likely that human cases are under‐reported or misdiagnosed. Future research should focus on the impact of CVV infection in human and animal populations.     

Controlled vocabularies for plant anatomical parts optimized for use in data analysis tools and for cross-species studies

Background

It is generally accepted that controlled vocabularies are necessary to systematically integrate data from various sources. During the last decade, several plant ontologies have been developed, some of which are community specific or were developed for a particular purpose. In most cases, the practical application of these ontologies has been limited to systematically storing experimental data. Due to technical constraints, complex data structures and term redundancies, it has been difficult to apply them directly into analysis tools.

Results

Here, we describe a simplified and cross-species compatible set of controlled vocabularies for plant anatomy, focussing mainly on monocotypledonous and dicotyledonous crop and model plants. Their content was designed primarily for their direct use in graphical visualization tools. Specifically, we created annotation vocabularies that can be understood by non-specialists, are minimally redundant, simply structured, have low tree depth, and we tested them practically in the frame of Genevestigator.

Conclusions

The application of the proposed ontologies enabled the aggregation of data from hundreds of experiments to visualize gene expression across tissue types. It also facilitated the comparison of expression across species. The described controlled vocabularies are maintained by a dedicated curation team and are available upon request.

     

Mandibular and sublingual sialocoeles in the dog: A retrospective evaluation of 41 cases,using the ventral approach for treatment

AIMS: To review results of the ventral approach for mandibular and sublingual sialoadenectomy for the treatment of sialocoeles associated with the mandibular and sublingual salivary glands in the dog, and to determine rates of recurrence and complication following this procedure.

METHODS: Thirty-nine dogs with 41 sialocoeles that underwent surgical intervention were retrospectively evaluated with respect to signalment, aetiology, location of sialocoeles, duration of clinical signs, treatment prior to referral, post-operative use of antibiotics and drains, complications, and recurrence.

RESULTS: The mean age at the time of surgery was 5.1 (SD 3.8) years, and duration of clinical signs 6.6 (SD 10.6) months. Long-term follow-up was available for 31 dogs; the minimum was 8 months and mean 47.7 (SD 25.8) months post-surgery. There was no recurrence of sialocoeles following the ventral approach for mandibular and sublingual sialoadenectomy. Post- operatively, 6/35 (17%) cases developed a seroma at the surgical site. No breed or sex predisposition was determined. The cause of the sialocoele was unknown in 36/41 (88%) cases.

CONCLUSIONS AND CLINICAL RELEVANCE: Excellent clinical results were achieved with a low rate of complications using the ventral approach for mandibular and sublingual siaload- enectomy. The ventral approach is recommended to minimise the risk of recurrence of sialocoeles.     

Woodland vegetation and its implications for archaeological survey using LiDAR

Archaeological surveys in woodland have always been problematicand many woodlands contain an unrecorded archaeological resource.For other types of rural landscape, aerial photographs are oftenused to map archaeological features but woodland cover has alwaysimpeded such disclosure. Remote sensing methods are rapidlyevolving and are used both within forestry and archaeologicaldisciplines for a range of applications. This paper considersthe exciting application of the remote sensing technique ofairborne Light Detection and Ranging (LiDAR) to reveal archaeologicalevidence previously hidden below a woodland canopy. Our researchshows how different types of woodland canopy and understoreyvegetation greatly influence the effectiveness of the LiDARto perform these surveys. A simple, visual vegetation mappingassessment is tested and its ability to predict the potentialof the LiDAR considered. This work highlights the importanceof vegetation awareness when considering both a new LiDAR surveyfor a woodland, and when interpreting the data. Simple estimatesof LiDAR penetration of the woodland canopy and understoreyvegetation can be used to predict the effectiveness of a LiDARsurvey in disclosing archaeological evidence and aid the interpretationof results.