Persistent haematuria and proteinuria due to glomerular disease in related Abyssinian cats

Eight cases of glomerular disease in young, related Abyssinian cats are described. Haematuria was the most consistent feature. Six cats developed the nephrotic syndrome. The short-term prognosis was good for cats with haematuria and fair for cats with the nephrotic syndrome as oedema resolved in three of the six cats. Light microscopic examination of renal biopsies from three cats was considered normal or revealed only mild abnormalities. In the three cases subjected to necropsy, histological abnormalities included mild mesangial hypercellularity and adhesions between the glomerular tuft and Bowman's capsule consistent with a focal proliferative glomerulopathy. Further investigation into this glomerulopathy will require ultrastructural and immunohistochemical studies to characterise the glomerular abnormality and genetic analyses to investigate its potential to be an inherited disease. Glomerular disease, potentially a familial one, should be considered in the investigation of persistent haematuria or proteinuria in Abyssinian and related cats.     

Distribution of toxigenic Escherichia coli serotypes in the intestines of infants.

As part of an ongoing study into the pathogenesis of sudden infant death syndrome (SIDS), the distribution of serotypes of toxigenic and non-toxigenic Escherichia coli within the gastrointestinal tract of babies who had died was investigated. Escherichia coli isolates from the mid-ileum, colon and rectum of six SIDS cases and one case which had died suddenly and unexpectedly but had underlying cardiac pathology were "O" serogrouped and examined for verocytoxic activity and production of heat-labile enterotoxin. In addition, the effect of storage of gut specimens and rectal swabs at 4 degrees C on isolation of toxigenic strains was studied in three of the cases. A diversity of serogroups and toxigenicity was a general finding, however, strains found in the proximal gut were also cultured from the rectum, indicating that faecal specimens would be a valid tool in investigating the role of these organisms in SIDS cases compared with healthy controls. Storage for up to 5 days at 4 degrees C had no appreciable effect on isolation rates of toxigenic bacteria.     

Risk factors for bacterial zoonotic pathogens in acutely febrile patients in Mpumalanga Province,South Africa

Endemic zoonoses, such as Q fever and spotted fever group (SFG) rickettsiosis, are prevalent in South Africa, yet often undiagnosed. In this study, we reviewed the demographics and animal exposure history of patients presenting with acute febrile illness to community health clinics in Mpumalanga Province to identify trends and risk factors associated with exposure to Coxiella burnetii, the causative agent of Q fever, and infection by SFG Rickettsia spp. Clinical and serological data and questionnaires elucidating exposure to animals and their products were obtained from 141 acutely febrile patients between 2012 and 2016. Exposure or infection status to C. burnetii and SFG Rickettsia spp. was determined by presence of IgG or IgM antibodies. Logistic regression models were built for risk factor analysis. Clinical presentation of patients infected by SFG rickettsiosis was described. There were 37/139 (27%) patients with a positive C. burnetii serology, indicative of Q fever exposure. Patients who had reported attending cattle inspection facilities (“dip tanks”) were 9.39 times more likely to be exposed to Q fever (95% CI: 2.9–30.4). Exposure risk also increased with age (OR: 1.03, 95% CI: 1.002–1.06). Twenty‐one per cent of febrile patients (24/118) had evidence of acute infection by SFG Rickettsia spp. Similarly, attending cattle inspection facilities was the most significant risk factor (OR: 8.48, 95% CI: 1.58–45.60). Seropositivity of females showed a significant OR of 8.0 when compared to males (95% CI: 1.49–43.0), and consumption of livestock was associated with a decreased risk (OR: 0.02, 95% CI: 0.001–0.54). A trend between domestic cat contact and SFG rickettsiosis was also noted, albeit borderline non‐significant. In this endemic region of South Africa, an understanding of risk factors for zoonotic pathogens, including exposure to domestic animals, can help clinic staff with diagnosis and appropriate therapeutic management of acutely febrile patients as well as identify target areas for education and prevention strategies.     

Do Abrasion- or Temperature-Based Techniques More Effectively Relieve Physical Dormancy in Seeds of Cold Desert Perennials?

Seed dormancy can present a significant barrier to restoration outcomes in dryland systems. Physical and combinational (physical + physiological) dormancy are prevalent among seeds of many herbaceous perennials used in restoration of drylands throughout the western United States. Although many techniques designed to alleviate these dormancy traits exist, their efficacy is species specific, may result in embryo damage, and may have limited large-scale application. To identify the most effective means of dormancy alleviation with the potential to be used on an operational scale, we examined the effects of 16 temperature-based techniques (altering temperature and duration of wet heat, freezing and wet heat, and freeze-thaw cycles) and 6 abrasion-based techniques (altering pneumatic scarification length or using a single duration of manual scarification) on the enhancement of seed permeability among two physically dormant (western prairie clover [Dalea ornata {Douglas} Eaton & Wright] and Munro’s globemallow [Sphaeralcea munroana {Douglas} Spach]) and two combinationally dormant species (basalt milkvetch [Astragalus filipes Torr. ex A. Gray] and longspur lupine [Lupinus arbustus {Douglas} ex Lindl.]). We first assessed seed imbibition following exposure to all temperature- and abrasion-based techniques to identify those most successful at promoting seed permeability and then evaluated the effectiveness of those techniques through a series of germination experiments. For combinationally dormant species, we also tested whether exposure to GA₃ enhanced germination. Abrasion-based techniques were more effective than temperature-based techniques at improving water uptake across all species. Pneumatic scarification significantly improved germination, but optimal treatment durations were species specific. GA₃ did not enhance germination under the tested conditions. We conclude that pneumatic scarification is a fast, safe, and effective method for alleviating physical seed dormancy with a potential to be scaled up for operational use in restoration.     

Characteristics of photosynthesis and stomatal conductance in the shrubland species manuka (Leptospermum scoparium) and kanuka (Kunzea ericoides) for the estimation of annual canopy carbon uptake

Responses of photosynthesis to carbon dioxide (CO2) partial pressure and irradiance were measured on leaves of 39-year-old trees of manuka (Leptospermum scoparium J. R. Forst. & G. Forst.) and kanuka (Kunzea ericoides var. ericoides (A. Rich.) J. Thompson) at a field site, and on leaves of young trees grown at three nitrogen supply rates in a nursery, to determine values for parameters in a model to estimate annual net carbon uptake. These secondary successional species belong to the same family and commonly co-occur. Mean (+/- standard error) values of the maximum rate of carboxylation (hemi-surface area basis) (Vcmax) and the maximum rate of electron transport (Jmax) at the field site were 47.3 +/- 1.9 micromol m(-2) s(-1) and 94.2 +/- 3.7 micromol m(-2) s(-1), respectively, with no significant differences between species. Both Vcmax and Jmax were positively related to leaf nitrogen concentration on a unit leaf area basis, and the slopes of these relationships did not differ significantly between species or between the trees in the field and young trees grown in the nursery. Mean values of Jmax/Vcmax measured at 20 degrees C were significantly lower (P < 0.01) for trees in the field (2.00 +/- 0.05) than for young trees in the nursery with similar leaf nitrogen concentrations (2.32 +/- 0.08). Stomatal conductance decreased sharply with increasing air saturation deficit, but the sensitivity of the response did not differ between species. These data were used to derive parameters for a coupled photosynthesis-stomatal conductance model to scale estimates of photosynthesis from leaves to the canopy, incorporating leaf respiration at night, site energy and water balances, to estimate net canopy carbon uptake. Over the course of a year, 76% of incident irradiance (400-700 nm) was absorbed by the canopy, annual net photosynthesis per unit ground area was 164.5 mol m(-2) (equivalent to 1.97 kg C m(-2)) and respiration loss from leaves at night was 37.5 mol m(-2) (equivalent to 0.45 kg m(-2)), or 23% of net carbon uptake. When modeled annual net carbon uptake for the trees was combined with annual respiration from the soil surface, estimated net primary productivity for the ecosystem (0.30 kg C m(-2)) was reasonably close to the annual estimate obtained from independent mensurational and biomass measurements made at the site (0.22 +/- 0.03 kg C m(-2)). The mean annual value for light-use efficiency calculated from the ratio of net carbon uptake (net photosynthesis minus respiration of leaves at night) and absorbed irradiance was 13.0 mmol C mol(-1) (equivalent to 0.72 kg C GJ(-1)). This is low compared with values reported for other temperate forests, but is consistent with limitations to photosynthesis in the canopy attributable mainly to low nitrogen availability and associated low leaf area index.     

Phytohormones and shoot growth in a three-generation hybrid poplar family

Hybrid vigor for secondary growth in poplar has been linked with increased gibberellin (GA) concentration in cambial tissue, but the relationship between concentrations of GAs and hybrid vigor of primary growth has not been investigated. We explored associations between concentrations of GAs, abscisic acid (ABA) and indoleacetic acid (IAA) and shoot extension in a hybrid family of Populus deltoides Bartr. ex Marsh. (Clone ILL-129) and P. trichocarpa Torr. & Gray (Clone 93-968) and two F1 and 67 F2 genotypes. Rapidly elongating subapical internodes from shoots of 4-year-old clonal saplings were selected for hormone analysis. The F1 hybrids displayed heterosis (hybrid vigor) for primary growth as a result of the complementation of dominance for increased internode length from the P. trichocarpa parent and dominance for increased diameter from the P. deltoides parent. Internodes from the faster-elongating shoots of the P. trichocarpa parent had a fourfold higher concentration of bioactive GA1 and higher concentrations of GA20, GA44, GA29 and GA8 than the P. deltoides parent. However, the two fast-growing F1 hybrids had low concentrations of all five GAs, with concentrations similar to those of the slower-elongating P. deltoides parent. Concentrations of ABA and IAA were correlated with GA concentrations and there was thus no evidence of a consistent promoting or inhibiting effect of ABA or IAA within the F1 family. These results indicate that heterosis for internode growth was not primarily regulated by hormone concentration. The segregating population of F2 hybrids was analyzed to assess the possible utility of hormone screening as a selection tool. The internodes of most of the F2 hybrids were smaller than those of their F1 parents and the larger P. trichocarpa parent. Among the F2 hybrids, mature internode length varied fourfold, and was correlated with lengths of young, subapical internodes from which hormones were analyzed. In these internodes, GA1 concentrations were negatively correlated with length (r = 0.41), diameter (0.33) and mass (0.50). Indoleacetic acid concentration was negatively correlated only with diameter (r = 0.37) and positively correlated with GA1 (r = 0.46), whereas ABA concentration was not correlated with any parameter. Thus, in the F2 population, variation in hormone concentration was not primarily responsible for the variation in shoot growth, indicating that selection for individuals with high GA concentration may not be an effective strategy for identifying vigorous hybrid genotypes.