Osteopathology and selenium deficiency co-occurring in a population of endangered Patagonian huemul (Hippocamelus bisulcus)

Background: About 1,000 endangered Patagonian huemul deer (Hippocamelus bisulcus) remain in Chile and 350-500 in Argentina. Most groups (>100) are not recovering, and prevalence of osteopathology in Argentina was at least 57%. Here I describe relevant cases of osteopathology from a Chilean population which, however, recently also provided data on trace mineral status, supporting the initial hypothesis that nutrition may be a primary etiologic factor. Additionally, recent data on bone chemical composition of Argentine cases and soil analyses are discussed. Results: Fluoride levels in Argentine cases with osteopathology were low and fluorosis was discarded as an etiological factor. Selenium deficiency occurred in 73% of huemul from the Chilean population which exhibited several cases with osteopathology. The pathophysiognomy included extensive erosion; tooth loss;  porosification; perforations of palate, maxillar and mandibular bone with frequent exposure of tooth roots; and fractured mandibula. Areas currently used by remaining huemul have mainly acidic volcanic soils, which reduces selenium bioavailability: mean soil selenium levels from areas typically used by extant huemul were very deficient (0.19 ppm), corroborating documented overt selenium deficiency in local livestock and plants. The area of extant huemul is known to result in primary iodine deficiency in livestock which is aggravated by selenium deficiency. Conclusions: Currently the most parsimonious explanation for frequent osteopathology and lack of numerical recovery are the combined effects of selenium and iodine deficiencies based on: osteopathology in a population of selenium deficient huemul; selenium deficient livestock, plants and soils; acidic soils; and regional primary iodine deficiency. The nexus between mineral nutrition and population dynamics of huemul may be due to constraints on their movements to fertile lowlands, including the elimination of historic migratory traditions, and concomitant elimination of source populations

Badanie wymiany gazowej, powierzchni liści oraz plonowania roślin chmielu (Humulus lupinus L.) po przebytej infekcji wirusowej

The aim of the presented study is to demonstrate the recovery effect from the virus diseases on improvement of physiological characteristics and the yield formation of the saaz semi-early red-bine Osvald clone 72 plants, the Czech classical variety of the finely aromatic hops. The recovered and the non-recovered hop plants were studied in the experimental hop garden in the Czech hop-growing region in years 2000 and 2001. The photosynthetically active leaf area (vine leaves and axil leaves), the net photosynthetic rate, the dry matter of vine, the leaves and yield formation of cones were assessed during a growing season in the selected phases of the hop plants ontogeny. The presence of viruses shortened the growing season of the non-recovered hop plants. The influence of the biotic stress factor accelerated the accession to the generative phase of their development and at the same time shortened the time period of the hop cone creation. The hop plant recovery elongated the period of photosynthetic activity of leaves and formation of hop cones. The virus-free hop plants gave higher yield. The recovered and the non-recovered hop plants have a different accession to the critical developmental periods important for the hop cones yield formation. The acquired information is very well applicable in preparation of the virus-free hop growing technologies and in the process of plant breeding.Celem prezentowanej pracy było wykazanie wpływu stanu po-infekcyjnego wywołanego chorobą wirusową na niektóre parametry fizjologiczne oraz plonowanie 72 roślin chmielu średnio wczesnego klonu klasycznej, bardzo aromatycznej czeskiej odmiany Osvald. Doświadczenie przeprowadzono na roślinach po-infekcyjnych i wcześniej nie infekowanych, ale wykazujących obecność wirusa, w eksperymentalnym ogrodzie znajdującym się w czeskim regionie uprawy chmielu w latach 2000-2001. Fotosyntetycznie aktywna powierzchnia liści, wydajność fotosyntezy netto, sucha masa, formowanie się liści i plonowanie szyszek mierzono podczas sezonu wegetatywnego w wybranych fazach ontogenezy chmielu. Obecność wirusa skracała okres wzrostu roślin wcześniej nie infekowanych. Wpływ stresora biotycznego przyspieszała wejście w fazę generatywną i skrócenie okresu powstawania szyszek. Rośliny będące w stanie po-infekcyjnym charakteryzowały się wydłużonym okresem aktywności fotosyntetycznej liści i formowania szyszek. Rośliny wolne od wirusa wydawały wyższy plon. Rośliny pozbawione wirusa i wykazujące jego obecność różniły się tempem wchodzenia w okresy krytyczne, istotne dla plonowania szyszek. Nabyte informacje mogą być przydatne w technologii uwalniania roślin chmielu od wirusa oraz w pracach hodowlanych

Growth and photosynthesis of Upland and Pima cotton: response to drought and heat stress

WOS: 000368249900006The effects of drought and heat stress on physiology of two common cotton species, Gossypium hirsutum L. (Upland) and G. barbadense L. (Pima) were investigated in this study. Four consecutive 28-day pot experiments were carried out in a fully controlled growth chamber under four temperatures (25, 30, 35 and 40 degrees C), while two water treatments (well-watered and drought) were imposed for 10 days to both cotton species. Growth according to dry matter accumulation of G. barbadense was more limited by sole drought conditions (50%), whereas heat stress was more remarkable on growth of G. hirsutum (64%). Chlorophyll (Chl) a and b content were more temperature-sensitive in G. hirsutum than G. barbadense under well-watered conditions. The most noticeable decrease in drought-induced rates of photosynthesis rate (P-n), transpiration rate (E) and stomatal conductance (g(s)) were recorded under 35 degrees C, although genotypic variation was found under 25 degrees C. Higher water use efficiency was associated with higher temperature. Relative decrease in Chl a content, g(s) and maximal quantum efficiency of PSII exhibited by both species were distinctive physiological traits for heat and drought tolerance

Opportunistic bacteria and mass mortality in ungulates: lessons from an extreme event

Mass mortality events in wildlife are a growing concern. Under conditions of rapid global change, opportunistic responses in bacterial commensals, triggered by environmental stressors, may be increasingly implicated in die-offs. In 2015, over 200,000 saiga antelope died of hemorrhagic septicemia caused by the pathogen Pasteurella multocida serotype B. We use this case to explore die-offs from commensal bacteria more broadly, looking at factors which might favor such extreme events. We review other recorded disease outbreaks caused by Pasteurellaceae organisms, firstly in saiga and secondly in other wild ungulates, and ask whether the 2015 die-off was unprecedented in terms of mortality rates, numbers dead and spatial scale, and in the nature of the predisposing or environmental factors involved. We also compare these outbreaks with mass mortality events associated with commensal bacteria in wildlife more generally. We identify three additional major die-offs in saiga in which Pasteurellaceae organisms may be implicated, of which one in 1988 closely resembles the 2015 hemorrhagic septicemia event. No other recorded cases in wild ungulates approach the magnitude of these cases for any of the metrics considered, possible exceptions being die-offs in Mongolian gazelles, in which the role of these pathogens is poorly substantiated. Environmental triggers were the most commonly suggested factor leading to pathogenesis, with warm humid conditions most commonly associated with hemorrhagic septicemia. Life history may also be significant – saigas are migratory and the largest pasteurellosis outbreaks outside this species also occur in migratory species of bird or other temperate ungulates aggregating in large numbers. Cases provoked by other commensals tend to be small in magnitude. Exceptions involve interactions between multiple pathogens and climatic conditions or sets of climatic conditions acting on different stages of the host-pathogen life cycle, leading to time lags between infection and subsequent disease. Overall, the scale and rapidity of the saiga die-offs appear unprecedented amongst mortality events caused by bacterial commensals in wild mammals. Experimental research into the genetics and micro-biology of host-pathogen interactions upon changes in the external environment, and monitoring of animals and conditions at calving sites, may eventually reveal the underlying causes of these die-offs