The reproductive biology of the moony,Monodactylus falciformis,in Algoa Bay

Gonadosomatic indices, macroscopic and microscopic examinations of gonads were used to establish the breeding cycle of Monodactylus falciformis. Spawning took place between October and February and evidence for serial spawning is presented.     

Gastric and intestinal surgery.

Gastric surgery is commonly performed to remove foreign bodies and correct gastric dilatation-volvulus and is less commonly performed to treat gastric ulceration or erosion, neoplasia, and benign gastric outflow obstruction. Intestinal surgery, although commonly performed by veterinarians, should never be considered routine. The most common procedures of the small intestinal tract performed in dogs and cats include enterotomy and resection/anastomosis. Surgery of the large intestine is indicated for lesions causing obstruction, perforations, colonic inertia, or chronic inflammation.     

Biomarkers predictive of long-term fertility found in vaginal lipidome of gilts at weaning

A marker indicative of the fertility potential of replacement gilts early in development would decrease culling rates in the sow herd, improve sow herd reproductive efficiency, and reduce production costs. The objective of this study was to determine if vaginal lipid profiles at 21 d postnatal (PN) could predict sow reproductive performance. Vaginal swabs of the anterior vagina were taken at 21 ± 4 d PN from gilts born on a commercial sow production facility for lipidomic analysis. Animals were followed prospectively for 2 yr and assigned to reproductive performance categories based on the observation of estrus or piglets weaned per sow per year (PSY) across two farrowings. Lipids were extracted from cellular material collected with swabs taken from high fertility (HF; n = 28; ≥26 PSY) and infertile (IF; n = 34; no estrus, no pregnancy) animals, and multiple reaction monitoring profiling was used for lipidome analysis. The relative abundance of arachidonic acid (C20:4) and docosahexaenoic acid (C22:6) was lower (P < 0.05) in IF gilts than HF gilts, whereas the abundance of the free fatty acids such as cerotic (C26:0), ximenic (C26:1), and nonadecanoic (C19:0) acids was greater (P < 0.05) in IF gilts. Additionally, eicosapentaenoic acid (C20:5), a precursor of prostaglandins, was higher (P < 0.05) in IF gilts. The perspective of having a panel of lipids captured with vaginal swabs at weaning that can predict the reproductive efficiency of gilts shows promise and warrants future research in this area.     

Evaluation of sampling methods to quantify abundance of hardwoods and snags within conifer-dominated riparian zones

? Aims

Six sampling alternatives were examined for their ability to quantify selected attributes of snags and hardwoods in conifer-dominated riparian areas of managed headwater forests in western Oregon.

? Methods

Each alternative was simulated 500 times at eight headwater forest locations based on a 0.52-ha square stem map. The alternatives were evaluated based on how well they estimated the number of hardwoods and snags per hectare and their basal area per hectare using root mean square error and percent bias.

? Results

In general, 3.6-m wide systematic strips oriented perpendicular to the stream outperformed the other alternatives. However, the variance of all six sampling alternatives was quite high and further research is needed to determine an optimal sampling method for quantifying hardwood and snag attributes in forests dominated by live conifers.

? Conclusion

When sampling snag and hardwood as a minor component of the overall forest composition within a riparian area, we suggest using 3.6-m strips perpendicular to the stream.     

Expression of lymphocyte homing and adhesion molecules during intramammary infection of cows with Serratiamarcescens or Streptococcusuberis: correlation with bacterial colonization and clinical signs

We wished to determine the expression of trafficking/adhesion molecules on the surface of lymphocytes isolated from infected mammary glands of cows challenged with either Serratia marcescens or Staphylococcus uberis. Healthy Holstein cows in mid lactation were infected by intramammary infusion with S. marcescens or S. uberis. Following infection, milk samples were collected at various time points. Body temperatures of the cows were taken, and milk was analyzed for colony forming units (CFU) of bacteria and somatic cell counts (SCC). Leukocytes were isolated from the milk and analyzed by flow cytometry. Percentages and types of lymphocytes were determined as well as expression of CD62L, CD11a, LPAM-1 and CD44 on these cells. We found that the percentage of lymphocytes expressing either CD62L or CD11a showed a marked increase 12 h post infection (PI) with S. marcescens that was not seen in cows infected with S. uberis. Conversely, the percentage of lymphocytes expressing CD44 increased in cows infected with S. uberis at 12 h PI, but the increase was not seen in cows infected with S. marcescens. Expression of LPAM-1 was low at all time points in both groups of cows. Body temperatures became elevated in both groups of cows, peaking at 24 h PI in S. marcescens-infected cows and dropping thereafter. In contrast, temperatures of S. uberis-infected cows continued to rise and were still elevated 96 h PI. CFU of bacteria isolated from mammary glands of S. marcescens-infected cows dropped precipitously 24 h PI but continued at high levels in S. uberis-infected cows. SCC began falling in S. marcescens-infected cows 48 h PI but continued to increase in S. uberis-infected cows. Thus, a greater percentage of lymphocytes in milk had a phenotype consistent with recruitment from the peripheral pool following infection with S. marcescens than was seen following infection with S. uberis. Concurrent with the increases seen in percentages of this lymphocyte phenotype, clinical signs lessened in the S. marcescens-infected cows.     

Studies on poly(acrylic acid) induced resistance to viral and non-viral plant pathogens

Studies on polymer size, concentration and mode of application, either as foliar spray or soil drench, in relation to the induction of resistance to tobacco mosaic virus (TMV) in Nicotiana tabacum cv xanthi-nc by poly(acrylic acid) (PA) are reported. PA also induced resistance to TMV in N. glutinosa, to pelargonium leaf curl virus in Datura stramonium, to cucumber mosaic virus in Vigna sinensis and to tobacco ring-spot virus in N. tabacum cv White Burley. No TMV was detected in PA-treated tomato cv Virocross 11 days after inoculation; but the susceptible cultivar Craigella became infected. PA treatment had no effect on TMV replication in White Burley tobacco but resistance was induced to Peronospora tabacina, a fungal pathogen of N. tabacum cv xanthi-nc. The potential of PA-induced resistance as a control measure for viruses and fungi is discussed.     

Temporal patterns of nutrient availability around nests of leaf-cutting ants (Atta colombica) in secondary moist tropical forest

Leaf-cutting ants consume up to 10% of canopy leaves in the foraging area of their colony and therefore represent a key perturbation in the nutrient cycle of tropical forests. We used a chronosequence of nest sites on Barro Colorado Island, Panama, to assess the influence of leaf-cutting ants (Atta colombica) on nutrient availability in a neotropical rainforest. Twelve nest sites were sampled, including active nests, recently abandoned nests (<1 year) and long-abandoned nests (>1 year). Waste material discarded by the ants down-slope from the nests contained large concentrations of nitrogen and phosphorus in both total and soluble forms, but decomposed within one year after the nests were abandoned. Despite this, soil under the waste material contained high concentrations of nitrate and ammonium that persisted after the disappearance of the waste, although soluble phosphate returned to background concentrations within one year of nest abandonment. Fine roots were more abundant in soil under waste than control soils up to one year after nest abandonment, but were not significantly different for older sites. In contrast to the waste dumps, soil above the underground nest chambers consistently contained lower nutrient concentrations than control soils, although this was not statistically significant. We conclude that the ‘islands of fertility’ created by leaf-cutting ants provide a nutritional benefit to nearby plants for less than one year after nest abandonment in the moist tropical environment of Barro Colorado Island.