When agroforests drive back natural forests: A socio-economic analysis of a rice-agroforest system in Sumatra

In the Krui arae, (South Sumatra, Indonesia), the damar agroforests (Shorea javanica, Dipterocarpaceae) are but one element of the farming systems which include several other cropping systems such as irrigated or rainfed rice cultivation, and coffee plantation.Rainfed rice is cultivated in forest clearings, in order to meet rice requirements which cannot be met with irrigated rice crop only. In the forest clearings, coffee stands are established in rice crop, and later, Damar are planted among coffee plants. As a result of this cropping system, the damar agroforest spreads while the forest dwindles.In one village, no more forest land is available for peasants' clearings. The resulting high land pressure causes cropping systems and farming systems to change or to be exported to neighbouring areas where forest land is still available.

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Résumé Les agroforêts à damar (Shorea javanica) ne sont qu'un élément du système d'exploitation agricole de la région de Krui, Sud Sumatra, Indonésie. Ceux-çi associent plusieurs systèmes de culture tels que la riziculture irriguée, la culture du riz pluvial et la plantation de cafeiérs.L'insuffisance des surfaces en rizières irriguées est compensée par la culture du riz pluvial, pratiquée en ladang, parcelle de forêt défrichée et brûlée. Sur les ladangs se succèdent les cultures de riz, de café puis de damar, transformant ainsi la forêt naturelle en agroforêt à damar. On assiste à l'extension continue des agroforêts au détriment de la forêt naturelle.Dans un des villages étudiés, la réserve de terres forestières communales est épuisée, déjà transformée en agroforêts. La forte pression fonçière qui en résulte induit des transformations dans les systèmes de production agricole ou incite des agriculteurs à migrer dans des régions voisines encore riches en terres forestières. Dans ces régions, les migrants reproduisent un système agroforestier très proche de celui de Krui, dans la mesure où les conditions écologiques le permettent.

     

Antidiabetic activity of red wine polyphenolic extract, ethanol, or both in streptozotocin-treated rats

A polyphenol extract from a Corbières (France) red wine (P, 200 mg/kg), ethanol (E, 1 mL/kg), or a combination of both (PE) was administered by daily gavage for 6 weeks to healthy control or streptozotocin (60 mg/kg i.v.)-induced diabetic rats (180-200 g). Treatment groups included C or D (untreated control or diabetic) and CP, CE, or CPE (treated control) or DP, DE, or DPE (treated diabetic). P treatment induced a reduction in body growth, food intake, and glycemia in both CP and DP groups. In DP, hyperglycemia was reduced when measured 1 h after daily treatment but not at sacrifice (no treatment on that day). The hyperglycemic response to the oral glucose tolerance test (OGTT) and plasma insulin at sacrifice were impaired similarly in DP and D groups. In contrast, in DE or DPE, body growth was partially restored while hyperglycemia was reduced both during treatment and at sacrifice. In addition, hyperglycemia response to OGTT was reduced and plasma insulin was higher in DE or DPE than in D animals, indicating a long-term correction of diabetes in ethanol-treated animals. Morphometric studies showed that ethanol partially reversed the enlarging effect of diabetes on the mesenteric arterial system while the polyphenolic treatment enhanced it in the absence of ethanol. In summary, our study shows that (i). a polyphenol extract from red wine ("used at a pharmacological" dose) reduces glycemia and decreases food intake and body growth in diabetic and nondiabetic animals and (ii). ethanol ("nutritional" dose) administered alone or in combination with polyphenols is able to correct the diabetic state. Some of the effects of polyphenols were masked by the effects of ethanol, notably in diabetic animals. Further studies will determine the effect of "nutritional" doses of polyphenols as well as their mechanism of action.     

Genetic diversity and tetracycline resistance genes of Histophilus somni

Nasal swabs were collected at three time points from 2378 calves in four feedlots and cultured for Histophilus somni to assess genetic relatedness and tetracycline resistance. The proportions of animals carrying tetracycline resistant isolates were 0.32% at arrival, 14.82% at interim, and 0.80% at exit. The 606 H. somni isolates recovered were compared by pulsed-field gel electrophoresis (PFGE), screened for the presence of plasmids, and assessed for the tetracycline resistance genes tet(A), tet(B), tet(C), tet(E), tet(G), tet(H), tet(K), tet(L), tet(M) and tet(O) using multiplex polymerase chain reaction. Most of the isolates (98.6%) belonged to one of seven PFGE clusters (A-G) of closely related profiles with 77.7% of the isolates belonging to clusters C and D. Clusters A, B and E were associated with a higher proportion of tetracycline susceptible isolates. Genetic diversity of the isolates was highest at entry in the feedlot and lowest after the period when the animals received in-feed chlortetracycline (interim samples). Clusters A and E were more prominently represented at exit from the feedlot than other clusters. All resistant strains harboured the gene tet(H) while no other tetracycline resistance genes and no plasmids were detected with the methodology employed. It appears that genetic variability in H. somni in Alberta feedlots is low, dissemination likely occurs by clonal expansion, and resistance to tetracyclines is mediated by the tet(H) encoded efflux pump. Pulsotypes associated with tetracycline susceptible strains appear more common at exit suggesting that the in-feed oxytetracycline included throughout the feeding period is not sufficient to exert selective pressure for resistant strains.     

Surgical resection of a gastrointestinal stromal cell tumor by double enterectomy and partial pancreatectomy on a 13-year-old mixed breed dog

Surgical resection of a gastrointestinal stromal cell tumor by double enterectomy and partial pancreatectomy on a 13-year-old mixed breed dog. A 13 year-old, male, mixed breed dog, has been presented for an abdominal mass. The exam showed the presence of an ileo-caeco-colic mass adhered to the distal portion of the pancreas and the mid duodenum. A double enterectomy and a partial pancreatectomy were carried out and a diagnosis of gastrointestinal stromal cell tumor has been established.     

Biological control at work: demonstrating the complementary effects of natural enemies on two contrasting pests and the damage they cause

Journal of Pest Science - Natural pest control is a significant service supporting agricultural production. However, the relative contribution of several functional groups of natural enemies to...     

Regulation of replication fork progression through histone supply and demand

DNA replication in eukaryotes requires nucleosome disruption ahead of the replication fork and reassembly behind. An unresolved issue concerns how histone dynamics are coordinated with fork progression to maintain chromosomal stability. Here, we characterize a complex in which the human histone chaperone Asf1 and MCM2-7, the putative replicative helicase, are connected through a histone H3-H4 bridge. Depletion of Asf1 by RNA interference impedes DNA unwinding at replication sites, and similar defects arise from overproduction of new histone H3-H4 that compromises Asf1 function. These data link Asf1 chaperone function, histone supply, and replicative unwinding of DNA in chromatin. We propose that Asf1, as a histone acceptor and donor, handles parental and new histones at the replication fork via an Asf1-(H3-H4)-MCM2-7 intermediate and thus provides a means to fine-tune replication fork progression and histone supply and demand.     

Steroid hormone receptors ERα and PR characterised by immunohistochemistry in the mare adrenal gland

Background

Sex steroid hormone receptors have been identified in the adrenal gland of rat, sheep and rhesus monkey, indicating a direct effect of sex steroids on adrenal gland function.

Methods

In the present study, immunohistochemistry using two different mouse monoclonal antibodies was employed to determine the presence of oestrogen receptor alpha (ERalpha) and progesterone receptor (PR) in the mare adrenal gland. Adrenal glands from intact (n = 5) and ovariectomised (OVX) (n = 5) mares, as well as uterine tissue (n = 9), were collected after euthanasia. Three of the OVX mares were treated with a single intramuscular injection of oestradiol benzoate (2.5 mg) 18 – 22 hours prior to euthanasia and tissue collection (OVX+Oe). Uterine tissue was used as a positive control and showed positive staining for both ERalpha and PR.

Results

ERalpha staining was detected in the adrenal zona glomerulosa, fasciculata and reticularis of all mare groups. Ovariectomy increased cortical ERalpha staining intensity. In OVX mares and one intact mare, positive ERalpha staining was also detected in adrenal medullary cells. PR staining of weak intensity was present in a low proportion of cells in the zona fasciculata and reticularis of all mare groups. Weak PR staining was also found in a high proportion of adrenal medullary cells. In contrast to staining in the adrenal cortex, which was always located within the cell nuclei, medullary staining for both ERalpha and PR was observed only in the cell cytoplasm.

Conclusion

The present results show the presence of ERalpha in the adrenal cortex, indicating oestradiol may have a direct effect on mare adrenal function. However, further studies are needed to confirm the presence of PR as staining in the present study was only weak and/or minor. Also, any possible effect of oestradiol treatment on the levels of steroid receptors cannot be determined by the present study, as treatment time was of a too short duration.