Evaluation of computed tomographic anatomy of the equine metacarpophalangeal joint

OBJECTIVE: To determine the detailed computed tomography (CT) anatomy of the metacarpophalangeal (MCP) joint in healthy horses. SAMPLE POPULATION: 10 cadaveric forelimbs from 10 adult horses without orthopedic disease. PROCEDURES: CT of the MCP joint was performed on 4 forelimbs. In 1 of the limbs, CT was also performed after intra-articular injection of 30 mL of contrast medium (40 mg of iodine/mL). Transverse slices 1-mm thick were obtained, and sagittal and dorsal planes were reformatted with a slice thickness of 2 mm. The CT images were matched with corresponding anatomic slices from 6 additional forelimbs. RESULTS: The third metacarpal bone, proximal sesamoid bones, and proximal phalanx could be clearly visualized. Common digital extensor tendon; accessory digital extensor tendon; lateral digital extensor tendon; superficial digital flexor tendon (including manica flexoria); deep digital flexor tendon; branches of the suspensory ligament (including its attachment); extensor branches of the suspensory ligament; collateral ligaments; straight, oblique, and cruciate distal sesamoidean ligaments; intersesamoidean ligament; annular ligament; and joint capsule could be seen. Collateral sesamoidean ligaments and short distal sesamoidean ligaments could be localized but not at all times clearly identified, whereas the metacarpointersesamoidean ligament could not be identified. The cartilage of the MCP joint could be assessed on the postcontrast sequence. CONCLUSIONS AND CLINICAL RELEVANCE: CT of the equine MCP joint can be of great value when results of radiography and ultrasonography are inconclusive. Images obtained in this study may serve as reference for CT of the equine MCP joint.     

Eelgrass slabs, a soilless culture substrate that inhibits adhesion of fungi and oomycetes and enhances antioxidant activity in tomato

Composed of a marine plant, Zostera sp., eelgrass slabs are a novel organic substrate for soilless cultures used in tomato production. The benefit of using eelgrass slabs for growing tomatoes was assessed by comparing it with coconut fiber slabs in regard to contamination by Pythium spp. and to the antioxidant properties of tomato fruits. First, tomato root contamination by Pythium spp. was studied by direct plate counting, and a molecular comparison of fungal and oomycete communities was conducted using PCR-DHPLC. Second, the antioxidant properties of tomato fruits were analyzed by measuring total phenol and carotenoid contents and by evaluating radical scavenging activity. Compared to plants grown on coconut fiber slabs, those on eelgrass slabs presented a lower rate of Pythium spp. root contamination. Moreover, culture on eelgrass slabs produced fruits with better radical scavenging activity and higher total phenol content compared to controls. Carotenoid content was not affected by the type of substrate. This study highlights the value of detrital leaves of Zostera sp. as a substrate for soilless culture that reduces root contamination and also promotes the production of tomato fruits with better nutritional value.     

Modelling historical mesocosm data: Application of a fish bioenergetics model in semi‐natural conditions

Developing ecological models for accurately predicting the dynamics of a population and individual physiological processes in field conditions is a challenging task for ecosystem management and ecological risk assessment. Here, we propose to assess the relevance of a dynamic energy budget (DEB) model calibrated using data previously generated from laboratory experiments for adult three‐spined sticklebacks (Gasterosteus aculeatus) living in semi‐natural conditions. We compared different ways of integrating different data sets such as temperature and prey abundance obtained in mesocosm experiments to assess the predictive capacity of the model. By this study, we provide recommendations for developing an appropriate environmental scenario (e.g. natural variations of food and temperature) for using a DEB model in a field context. We conclude that a DEB model calibrated with laboratory data can be used to predict the physiological processes of an organism living in semi‐natural conditions, but that the reproductive behaviour of the organism can affect the predictions. At last, we suggest that further studies on the feeding behaviour may be necessary for immature organisms.     

Characterization of a Novel Conus bandanus Conopeptide Belonging to the M-Superfamily Containing Bromotryptophan

A novel conotoxin (conopeptide) was biochemically characterized from the crude venom of the molluscivorous marine snail, Conus bandanus (Hwass in Bruguière, 1792), collected in the south-central coast of Vietnam. The peptide was identified by screening bromotryptophan from chromatographic fractions of the crude venom. Tandem mass spectrometry techniques were used to detect and localize different post-translational modifications (PTMs) present in the BnIIID conopeptide. The sequence was confirmed by Edman’s degradation and mass spectrometry revealing that the purified BnIIID conopeptide had 15 amino acid residues, with six cysteines at positions 1, 2, 7, 11, 13, and 14, and three PTMs: bromotryptophan, γ-carboxy glutamate, and amidated aspartic acid, at positions “4”, “5”, and “15”, respectively. The BnIIID peptide was synthesized for comparison with the native peptide. Homology comparison with conopeptides having the III-cysteine framework (–CCx₁x₂x₃x₄Cx₁x₂x₃Cx₁CC–) revealed that BnIIID belongs to the M-1 family of conotoxins. This is the first report of a member of the M-superfamily containing bromotryptophan as PTM.     

Thermal denaturation and aggregation properties of Atlantic salmon myofibrils and myosin from white and red muscles

Thermal denaturation and aggregation abilities of salmon myofibrils and myosin were studied measuring turbidity, intrinsic fluorescence, 8-anilino-1-naphthalene sulfonic acid binding, and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide cross-linking. The thermal behaviors of protein preparation from white and red muscles were compared, and the relationship with thermal gelation properties is discussed. The low gelation ability of salmon muscle proteins was related to a limited extent of protein denaturation and aggregation upon heating. These properties seemed to be carried by myosin molecules as a similar behavior was observed for both myofibrils and myosin preparations. The higher thermal stability observed for red muscle proteins with higher transition temperatures in rheological profiles was related to a shift to higher temperature in denaturation and aggregation processes. The extent of denaturation and aggregation was very similar for both muscle types as was the final rigidity of the gels formed.     

Genotype by environment interaction effects on fibre components in potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.)

Increasing awareness of heart health and disease prevention has led consumers to more proactive grocery food choices. Fibre and its associated health benefits remains an important area of research given the current interest in food, nutrition, and health. To position the potato as a good source of fibre, breeding efforts have focused on developing cultivars and germplasm with high fibre content. The current study examined eight elite potato clones and four commercial cultivars (checks) across six environments (three locations over two years) for their total dietary fibre (TDF), neutral detergent fibre (NDF), and soluble fibre (SF) content. Genotype by environment interaction (GEI) and stability analysis were conducted with SAS and GGE Biplot software. Significant genotypic (G), environmental (E) and GEI effects were found. The six environments differed in temperature and moisture levels, which were linked to levels of NDF and TDF. Some genotypes had high levels of stability for fibre content. GGE biplot analysis found no significant mega-environments for fibre components. Two elite clones (CV96044-3 and F05081) were identified as high fibre sources (13.3 and 14.4 %, respectively) compared to the other elite clones and commercial cultivars (e.g., Russet Burbank: 11.7 %). These lines may also be suitable as parents with high fibre and stability to breed into backgrounds with other desirable qualities.     

Genetic structure, population dynamics, and conservation of Black caiman (Melanosuchus niger)

Microsatellite DNA polymorphisms were screened in seven populations of the largest Neotropical predator, the Black caiman Melanosuchus niger (n = 169), originating from Brazil, French Guiana and Ecuador. Eight loci were used, for a total of 62 alleles. The Ecuadorian population had the lowest number of alleles, heterozygosity and gene diversity; populations of the Guianas region exhibited intermediate diversities; highest values were recorded in the two populations of the Amazon and Rio Negro. During the last century Melanosuchus populations have been reduced to 1-10% of their initial levels because of hunting pressure, but no strong loss of genetic diversity was observed. Both the inter-locus g-test and the Pk distribution suggested no recent important recovery and/or expansion of current populations. On a global scale, the inter-population variation of alleles indicated strong differentiation (F_ST = 0.137).Populations were significantly isolated from each other, with rather limited gene flow; however, these gene flow levels are sufficiently high for recolonization processes to effectively act at regional scales. In French Guiana, genetic structuring is observed between populations of two geographically close but ecologically distinct habitats, an estuary and a swamp. Similar divergence is observed in Brazil between geographically proximate “black water” and “white water” populations. As a consequence, the conservation strategy of the Black caiman should include adequate ecosystem management, with strong attention to preservation of habitat integrity. Distribution of genetic diversity suggests that current populations originated from the central Amazonian region. Dispersal of the species may thus have been deeply influenced by major climatic changes during the Holocene/Pleistocene period, when the Amazonian hydrographic networks were altered. Major ecological changes such as glaciations, marine transgressions and a hypothesized presence of an Amazonian Lake could have resulted in extension of Black caiman habitats followed by isolation.     

Fate of 14C-ring-labeled 2,4-D, 2,4-dichlorophenol and 4-chlorophenol during straw composting

Experiments were carried out to study the transformation of ¹⁴C-ring-labeled 2,4-D and the two related chlorophenols 4-chlorophenol (4-CP) and 2,4-dichlorophenol (4-DCP) during straw composting under controlled laboratory conditions. Incubation under sterile and nonsterile conditions was done to evaluate the relative importance of the biotic and abiotic processes. Pre-composted straw was treated with the three chemicals. The availability of the different chemicals was monitored during incubations as well as their degradation. Under nonsterile conditions, the mineralization of both chlorophenols reached 20% of the applied compounds, whereas it was 52% for 2,4-D. Transitory water-soluble metabolites of 2,4-D and chlorophenols were formed but they disappeared rapidly. After 21 days, 21% of the 2,4-D and 38% of the 2,4-DCP was stabilized as nonextractable (bound) residues under nonsterile conditions. Bound residues of both chemicals were negligible under sterile conditions. Availability of chemicals as estimated by water extraction decreased during incubation proportionally to mineralization and to the formation of bound residues. The increase in immobilization of the chemical residues was stronger under nonsterile conditions than under sterile conditions. Under nonsterile conditions 71% of the 4-CP was recovered as bound residues, whereas under sterile conditions 30% of the applied 4-CP formed bound residues after formaldehyde addition and only 8% with autoclaved straw. Global microbial activity decreased in the presence of the chlorophenols probably due to their toxic effect. These data indicate that the biological activity associated with straw transformation during composting stimulates the depletion of 2,4-D and chlorophenols by mineralization and by formation of bound residues. Received: 6 September 1996     

Effect of repeated doses of albendazole on enantiomerism of its sulfoxide metabolite in goats.

Five adult Saanen goats were dosed orally 3 times with albendazole (2.5 mg/kg of body weight) at 24-hour intervals, and blood samples were taken by jugular venapuncture at standardized intervals. Plasma was analyzed to determine concentrations of S-oxidation metabolites, and a chiral column was used for enantiomeric discrimination of the sulfoxide metabolite of albendazole. Marked changes were evident between the first and subsequent plasma profiles concerning, on one hand, the proportions of sulfoxide and sulfone metabolites concentrations and, on the other hand, the enantiomeric balance of sulfoxide metabolite. These correlated phenomena may be explained by the following arguments: the enzyme responsible for sulfoxidation is mainly a flavine-containing monooxygenase, whereas the enzyme responsible for sulfonation is a cytochrome-dependent monooxygenase; the latter, but not the former, is induced by albendazole; the enantioselectivities of both enzymic systems are opposite, the flavine produces the (+) sulfoxide, whereas the cytochromes can use as a substrate, specifically, the (-) sulfoxide.     

Growth and N nutrition, monitored by enzyme assays, in a hardwood plantation: effects of mulching materials and glyphosate application

The effects of mulching materials (black plastic and straw) and herbicide application (glyphosate) on growth and nitrogen nutrition of butternut (Juglans cinerea), white ash (Fraxinus americana) and bur oak (Quercus macrocarpa) were studied in a plantation established in an abandoned field in southern Québec (Canada) since 1987. To ascertain the efficiency of mulching materials on the performance of tree seedlings, a herbicide (glyphosate, 6 l ha⁻¹) was applied in half of the experimental plots in June 1990 and 1991. Soil parameters (temperature, moisture) and soil nitrate and ammonium concentrations were measured during the growing season in 1991. In summer 1991, nitrogen nutrition of the seedlings was monitored using enzyme assays (nitrate reductase activity (NRA), glutamine synthetase activity (GSA)) of the leaves of the three deciduous tree species. Mulching affected soil parameters, with black plastic producing the highest soil temperature (23.4°C) and straw the highest soil moisture (183.6 g kg⁻¹) in June. NRA varied in relation to tree species, herbicide application, mulching material and time. GSA was poorly correlated to silvicultural treatments. Butternut showed the highest NRA, especially in herbicide plots irrespective of mulching material. Bur oak NRA showed less variation between herbicide and non-herbicide plots and reacted more to the mulching treatments. White ash NRA only showed an herbicide effect in June. All species reacted positively to the addition of an herbicide around the mulching material, but not to the same degree. Height and diameter increment ratios (with/without glyphosate application) indicate that butternut growth was the most improved by herbicide applications, followed by white ash and bur oak. This indicates that the effectiveness of mulching alone decreases in the following order: bur oak > white ash > butternut. The utilization of mulching material in abandoned fields as an alternative to herbicide application is closely linked to the species chosen. Enzyme assays (NRA) were shown to be a valuable tool for monitoring physiological status of planted trees subjected to environmental changes brought on by silvicultural practices.