In vitro effects of lipopolysaccharides on bovine uterine contractility

Metritis is an important disorder in dairy cows during the early postpartum period. Myometrial contractility is a prerequisite for uterine involution; however, very scanty literature is available about the effect of metritis on this process and endocrine responsiveness. This study was aimed to evaluate the effect of inflammation on uterine contractility in vitro, and the inflammation was induced by incubating myometrial strips with lipopolysaccharides (LPS). Myometrial samples were collected from 17 healthy Holstein Friesian cows during caesarean section. Eight longitudinal strips from each cow were incubated in organ baths with LPS concentrations of 0 (LPS₀), 0.1 (LPS_0.1), 1 (LPS₁) and 10 µg/ml (LPS₁₀). Spontaneous contractility and contractility induced by increasing concentrations of oxytocin (10^–10 – 10^–7 mol/L) were recorded during nine 30-min intervals (T1 to T9). The minimum amplitude (minA), maximum amplitude (maxA), mean amplitude (meanA) and area under the curve (AUC) were calculated for each time interval. LPS had an effect (p ≤ .05) on maxA, meanA and AUC. In T1, myometrial strips incubated with LPS_0.1 and LPS₁ had higher (p ≤ .05) maxA, meanA and AUC than the strips incubated with LPS₀. In T9 without oxytocin, LPS₀ led to higher (p ≤ .05) maxA, meanA and AUC than LPS_0.1 and LPS₁. In T8 and T9 with oxytocin, LPS₁ had lower (p ≤ .05) maxA, meanA and AUC than the other LPS concentrations. Interestingly, the results show that LPS has a transient positive effect on myometrial contractility in vitro and that this effect is dependent on LPS concentration and duration of incubation.     

Does apoplastic ascorbic acid enhance manganese tolerance of Vigna unguiculata and Phaseolus vulgaris?

In cowpea (Vigna unguiculata), the development of manganese (Mn) toxicity is considered to be accompanied by the formation of reactive oxygen species, oxidized Mn, and phenoxy radicals in the leaf apoplast. Ascorbic acid (AA) is a common antioxidant in plants, and the oxidation of AA, particularly in the leaf apoplast, contributes to the first line of defence against several biotic and abiotic stress factors. The objective of the present study was to contribute to a better understanding of the role of AA in Mn leaf‐tissue tolerance of cowpea and common bean (Phaseolus vulgaris). Five cowpea cultivars (cvs.) differed greatly in Mn tolerance, which was expressed in differences in numbers of brown spots on leaves and in peroxidase (POD) activity in the apoplastic washing fluid (AWF). In a Mn‐sensitive cv., after 3 d of Mn treatment, brown spots were formed, and POD activities were increased, accompanied by a release of proteins into the apoplast. In the AWF, the concentration of AA and the ratio of AA : (AA+DHA) decreased already after 1 d, and to only 2% after 3 d. In the leaf tissue, the ratio was nearly unaffected, and the total AA+DHA content in the leaf tissue was even increased with advanced expression of Mn toxicity. The application of AA solutions in the range of 5–10 μM via the petiole slightly enhanced Mn tolerance as indicated by the reduction of brown spots (however inconsistently) and POD activity (consistently) in the AWF. Common bean cultivars differing in ozone tolerance, which has been reported to be due to a high AA availability in the leaf apoplast, were studied for their Mn tolerance. Clear differences in Mn tolerance between the cultivars existed, however, these differences were not related to their ozone tolerance. From these results, we conclude that the maintenance of sufficient AA levels in the leaf apoplast contribute to Mn tolerance, but does not fully explain genotypic differences in Mn tolerance in cowpea and common bean.     

Insectivorous songbirds as early indicators of future defoliation by spruce budworm

Landscape Ecology - Although the spatiotemporal dynamics of spruce budworm outbreaks have been intensively studied, forecasting outbreaks remains challenging. During outbreaks, budworm-linked...     

Long‐term successful treatment of a donkey with cutaneous lupus erythematous with methotrexate

Cutaneous lupus erythematosus (CLE) is a rare immune‐mediated dermatitis. To the best of the authors’ knowledge it has not been described in donkeys. A 5‐year‐old male neutered donkey, living in south‐east France, was diagnosed with CLE. Clinical signs included generalized symmetrical areas of alopecia, erythema, crusting and scales. Diagnostic tests included examination of skin biopsy samples by histopathological and immunohistochemical analysis which demonstrated an interface dermatitis with CD8+ T cells. The skin condition was successfully treated initially with glucocorticoids and methotrexate; successful long‐term maintenance was associated with administration of methotrexate.     

Methodology for drawing up a Red List of threatened freshwater fish in France

• 1. In 1995, the IUCN implemented new definitions to be used when drawing up red lists. However, in addition to being imprecise for fish species, these remain difficult to apply.
• 2. This paper describes a more exhaustive method under the IUCN (1995) definitions based on six quantitative and qualitative criteria where scientific data are given the greatest possible weight, as compared with ‘expert opinion’. This dual system makes it possible both to allocate an IUCN category to each species, and to rank each species within a particular category according to given scores, so that priorities can be determined.
• 3. The new Red List for French Freshwater Fish drawn up with this method contains 27 species, or 54% of the French native fauna. Three species are extinct (EX), four are critically endangered (CR), two are endangered (EN), 14 are vulnerable (VU), and four are at lower risk (LR).
• 4. Based on sounder scientific grounds, this list modifies and replaces the one drawn up in 1992. In effect, it makes it easier to argue for the presence of one species in one category rather than in another.

Copyright © 2002 John Wiley & Sons, Ltd.     

How does drought tolerance compare between two improved hybrids of balsam poplar and an unimproved native species?

Poplars are one of the woody plants that are very sensitive to water stress, which may reduce the productivity of fast-growing plantations. Poplars can exhibit several drought tolerance strategies that may impact productivity differently. Trees from two improved hybrids, Populus balsamifera?×?Populus trichocarpa Torr. & Gray (clone B?×?T) and P. balsamifera?×?Populus maximowiczii A. Henry (clone B?×?M), having P. balsamifera L. as a parent and trees from native and unimproved P. balsamifera were subjected to a 1-month drying cycle in a growth chamber and then rewatered. The unimproved and native B clone maintained higher stomatal conductance (g(s)) than the hybrids, and high photosynthetic activity and transpiration, even when soil water content was nearly zero. As a result, both instantaneous water use efficiency (WUE(i)) and leaf carbon isotope composition (δ(13)C) indicated that this clone was less affected by drought than both hybrids at maximal drought stress. However, this clone shed its leaves when the drought threshold was exceeded, which implied a greater loss of productivity. The B?×?M hybrid showed a relatively conservative response to water stress, with the greatest decrease in transpiring versus absorbing surface (total leaf area to root biomass ratio). This clone was also the only one to develop new leaves after rewatering, and its total biomass production was not significantly decreased by drought. Among the two hybrids, clone B?×?T was the most vigorous, with the greatest transpiration (E(i)) and net CO(2) assimilation (A) rates, allowing for high biomass production. However, it had a more risky strategy under drought conditions by keeping its stomata open and high E(i) rates under moderate drought, resulting in a lower recovery rate after rewatering. The opposite drought response strategies of the two hybrids were reflected by clone B?×?T having lower WUE(i) values than clone B?×?M at maximal drought, with a very low Ψ(min) value of -3.2 MPa, despite closed stomata and stopped photosynthetic activity. Positive linear relationships between A and g(s) for the three hybrids indicated strong stomatal control of photosynthesis. Moreover, the three poplar clones showed anisohydric behaviour for stomatal control and their use under long-term drought should be of interest, especially the B?×?M clone.     

Contribution of forest management artefacts to plant diversity at a forest scale

• Introduction   

Most temperate forests are managed for wood production, and some forestry practices generate typical environmental features such as roads, paths, ditches and tractor ruts, which are likely to affect forest species distribution.     

Structural and functional changes of neuronal and glial components of the feline enteric nervous system in cats with chronic inflammatory and non-inflammatory diseases of the gastrointestinal tract

Immunohistochemical examinations of the enteric nervous system (ENS) were performed on biopsies of healthy cats and compared to findings in cats suffering from inflammatory bowel disease or intestinal lymphoma. In lymphocytic–plasmacytic enterocolitis all affected samples had significant reductions in glial fibrillary acidic protein and vasoactive intestinal peptide (VIP) and mostly of neuron-specific enolase (NSE) possibly reflecting alterations in enteric glial cells and neurons. In cases with eosinophilic gastroenterocolitis significantly reduced phosphorylated neurofilament (PN) expression was present suggesting a disturbance in neuronal cytoskeleton, whereas cats with fibrosing enteropathy had reduced expression of NSE, non-phosphorylated neurofilaments (NPN), PN and VIP, possibly reflecting neuronal disturbances. In cases with intestinal lymphoma only the reduction in PN and the increase in NPN were obvious suggesting direct damage or interference of neoplastic cells with enteric neurons. In conclusion, structural and functional alterations of the ENS may contribute to clinically evident signs of vomiting and/or diarrhea.