Using simulation and budget models to scale-up nitrogen leaching from field to region in Canada

Efforts are underway at Agriculture and Agri-Food Canada (AAFC) to develop an integrated, nationally applicable, socioeconomic/biophysical modeling capability in order to predict the environmental impacts of policy and program scenarios. This paper outlines our Decision Support System (DSS), which integrates the IROWCN (Indicator of the Risk of Water Contamination by Nitrogen) index with the agricultural policy model CRAM (Canadian Regional Agricultural Model) and presents an outline of our methodology to provide independent assessments of the IROWCN results through the use of nitrogen (N) simulation models in select, data-rich areas. Three field-level models--DSSAT, N_ABLE, and EPIC--were evaluated using local measured data. The results show that all three dynamic models can be used to simulate biomass, grain yield, and soil N dynamics at the field level; but the accuracy of the models differ, suggesting that models need to be calibrated using local measured data before they are used in Canada. Further simulation of IROWCN in a maize field using N_ABLE showed that soil-mineral N levels are highly affected by the amount of fertilizer N applied and the time of year, meaning that fertilizer and manure N applications and weather data are crucial for improving IROWCN. Methods of scaling-up simulated IROWCN from field-level to soil-landscape polygons and CRAM regions are discussed.     

Regulation of MTP expression in developing swine

To define the developmental expression of microsomal triglyceride transfer protein (MTP) large subunit mRNA and protein, samples of small intestine and liver were collected from 40-day gestation fetal, 2-day-old newborn, 3-week-old suckling, and 2-month-old weanling swine. In fetal animals, MTP mRNA expression was high in intestine and liver. Postnatally, jejunal expression paralleled the intake of a high-fat breast milk diet and declined after weaning. Ileal expression was comparable with that of jejunum in 2-day-old animals, but declined to low levels afterward. Hepatic expression declined postnatally and remained low. MTP protein expression generally paralleled mRNA expression, except in fetal intestine in which no 97 kDa protein was detected. In 2-day-old piglets, a high-triacylglycerol diet increased jejunal and ileal MTP mRNA levels, as compared to a low-triacylglycerol diet. To test the roles of glucocorticoids and fatty acids in MTP regulation, a newborn swine enterocyte cell line (IPEC-1) was used. Except at day 2 of differentiation, dexamethasone did not influence MTP expression. Fatty acids either up-regulated or down-regulated MTP expression, depending on the specific fatty acid and duration of exposure. Although programmed genetic cues regulate MTP expression during development, clearly the amount and fatty acid composition of dietary lipid also play regulatory roles.     

Comparison of tissue culture and animal models for assessment of Cryptospridium parvum infection

The current increased interest for using tissue culture as a surrogate for mouse infection to assess Cryptospridium viability suggests that a comparison of the two models is essential for data interpretation. Therefore, a need remains for a statistical comparison that can demonstrate if infection and inactivation predicted by new tissue culture models are comparable with those predicted by animal models. Data from a total of 31 dose-response trials using both tissue culture and mouse models to assess C. parvum infectivity were compared. The dose needed to infect 50% of the tissue cultures (ID(50)) was also compared to each ID(50) in mice. Average ID(50)s developed using the logit dose-response method for tissue culture and mice were 8 and 107, respectively, suggesting that tissue culture was more sensitive to infection. However, correlation (r) between tissue culture and mouse infectivity was statistically significant (0.9167 [95% CI=0.8428 to 0.9594, p<0.0001]). Comparison of oocyst disinfection by UV and chlorine dioxide showed no significant difference between inactivation predicted by tissue culture and mouse models (p=0.8893; t=0.0141; n=21). These results demonstrate that tissue culture can successfully be used to measure C. parvum infection and can be used for determining inactivation in disinfection studies.     

Increase in tannin consumption by sifaka (<Emphasis Type="Italic">Propithecus verreauxi verreauxi</Emphasis>) females during the birth season: a case for self-medication in prosimians?

In this study we report preliminary data on the consumption of tannin-rich plants by sifakas (Propithecus verreauxi verreauxi) living in the Kirindy forest, western Madagascar. Sifakas spent most of their time feeding on only a few plant species. The tannin intake during the period between the pregnancy and birth season was significantly higher in pregnant females or females with lactating infants than in non-reproductive females and males. These periparturient females secured a larger proportion of condensed tannins by short feeding bouts on plants not included in the group's limited preferred food species. The measured increase in tannin intake is puzzling in light of the fact that tannins are commonly known for their protein-binding properties. Since protein demands are highest in pregnant and lactating females, possible medicinal benefits of tannin ingestion are considered. Tannin consumption is associated with an increase in body weight and stimulation of milk secretion. Veterinarians administer tannins as an astringent, anti-hemorrhagic and anti-abortive. Their high potential as an alternative anthelminthic has also recently been recognized. Thus, when viewed as self-medicating behavior, controlled increase in tannin intake could have multiple prophylactic advantages for females during the periparturient period. The high selectivity in their plant choice, and the presence of unusual feeding habits by a particular group of individuals (females with infants) limited in time (birth season), suggests that an increase in tannin ingestion may be a self-medicating behavior with multiple directly adaptive benefits to female reproduction. Electronic Publication     

Extraordinarily low bone mineral density in an old female chimpanzee (<Emphasis Type="Italic">Pan troglodytes schweinfurthii</Emphasis>) from the Mahale Mountains National Park

We examined bone mineral density (BMD) of the femoral neck and lumbar vertebrae of four chimpanzee skeletons from Mahale Mountains National Park, Tanzania, and four captive ones, with a dual energy X-ray absorptiometer. The BMD of Wansombo, an old female chimpanzee from Mahale , was remarkably lower than the mean of the other six younger adult female chimpanzees and categorized as osteoporosis. Posture, locomotion, and trunk-sacral anatomy of chimpanzees may have prevented fractures in Wansombo, whose BMD was below human osteoporosis criteria. Electronic Publication     

Phenylbutyrates as potent,orally bioavailable vitronectin receptor (integrin alphavbeta3) antagonists

In our continuing efforts to identify small molecule vitronectin receptor antagonists, we have discovered a series of phenylbutyrate derivatives, exemplified by 16, which have good potency and excellent oral bioavailability (approximately 100% in rats). This new series is derived conceptually from opening of the seven-membered ring of SB-265123.     

Synthesis and pharmacology of a hybrid cannabinoid

A pentacyclic hybrid cannabinoid (4) has been synthesized, which combines structural elements of traditional cannabinoids and cannabmimetic indoles. Cannabinoid 4 contains a 1-pentylindole structure fused to the 2,3-positions of the partially reduced hydroxydibenzopyran system of THC. The successful approach to 4 employed 9-benzoyl-5,7-dimethoxy-1,2,3,4-tetrahydrocarbazole (17) as the starting material. Dehydrogenation to carbazole 18, followed by demethylation and condensation with trans-p-menthadienol gave N-benzoyl hybrid cannabinoid 22, N-alkylation of which afforded target cannabinoid 4. The hybrid cannabinoid had affinity for the CB1 receptor approximately equal to that of delta8-THC (Ki = 19.3+/-3 nM), and shows comparable potency in vivo.     

Synthesis and pharmacology of the isomeric methylheptyl-Δ-tetrahydrocannabinols

The synthesis of the 3-heptyl, and the eleven isomeric 3-methylheptyl-Δ⁸-tetrahydrocannabinols (3–7, R and S methyl epimers, and 8) has been carried out. The synthetic approach entailed the synthesis of substituted resorcinols, which were subjected to acid catalyzed condensation with trans-para-menthadienol to provide the Δ⁸-THC analogue. The 1′-, 2′- and 3′-methylheptyl analogues (3–5) are considerably more potent than Δ⁸-THC. The 4′-, 5′- and 6′-methylheptyl isomers (6–8) are approximately equal in potency to Δ⁸-THC.     

Gastrointestinal parasites of the chimpanzee population introduced onto Rubondo Island National Park,Tanzania

The release of any species into a novel environment can evoke transmission of parasites that do not normally parasitize the host as well as potentially introducing new parasites into the environment. Species introductions potentially incur such risks, yet little is currently known about the parasite fauna of introduced primate species over the long term. We describe the results of long‐term monitoring of the intestinal parasite fauna of an unprovisioned, reproducing population of chimpanzees introduced 40 years earlier (1966–1969) onto Rubondo Island in Lake Victoria, Tanzania, a non‐native habitat for chimpanzees. Two parasitological surveys (March 1997–October 1998 and October 2002–December 2005) identified Entamoeba spp. including E. coli, Iodamoeba buetschlii, Troglodytella abrassarti, Chilomastix mesnili, Trichuris sp., Anatrichosoma sp., Strongyloides spp., Strongylida fam. gen. sp., Enterobius anthropopitheci, Subulura sp., Ascarididae gen. sp., and Protospirura muricola. The parasite fauna of the Rubondo chimpanzees is similar to wild chimpanzees living in their natural habitats, but Rubondo chimpanzees have a lower prevalence of strongylids (9%, 3.8%) and a higher prevalence of E. anthropopitheci (8.6%, 17.9%) than reported elsewhere. Species prevalence was similar between our two surveys, with the exception of Strongyloides spp. being higher in the first survey. None of these species are considered to pose a serious health risk to chimpanzees, but continued monitoring of the population and surveys of the parasitic fauna of the two coinhabitant primate species and other animals, natural reservoir hosts of some of the same parasites, is important to better understand the dynamics of host–parasite ecology and potential long‐term implications for chimpanzees introduced into a new habitat. Am. J. Primatol. 72:307–316, 2010. © 2009 Wiley‐Liss, Inc.     

Principles and levels of laterality in unimanual and bimanual stone handling patterns by Japanese macaques

The preferential use of one hand over the other is considered the primary behavioral expression of structural and functional asymmetry in cerebral structures, which is a decisive factor in human evolution. We present the first analysis of manual laterality in a form of object play—stone handling (SH) behavior—in a free-ranging group of Japanese macaques. Defined as a stone-directed manipulative activity, and comprised of multiple one-handed SH patterns (e.g., grabbing a stone in one hand and cradling it against its chest), as well as coordinated two-handed SH patterns with manual role differentiation (e.g., holding a stone with one hand and rubbing it with the other), SH behavior is a good candidate for the study of hand lateralization. We systematically followed the methodological framework developed by McGrew and Marchant (1997) to measure and analyze the presence, strength, and direction of manual preference in the performance of SH behavior and in various SH patterns, both at the individual and group level. Some individuals showed a significant manual lateral bias on a single SH pattern (hand preference), whereas others showed consistency in laterality across all or most of the SH patterns they performed (hand specialization). At the group level, we found that, although their collective distribution of left versus right remained random, most subjects were either significantly but incompletely lateralized, or completely lateralized within particular SH patterns (pattern specialization), but not across all SH patterns (no handedness for SH behavior as a whole). As predicted by the task-complexity model, hand specialization and handedness were stronger in the coordinated bimanual SH patterns than in the unimanual patterns. We discuss the implications of our findings for the evolution of manual preferences in noninstrumental object manipulation versus stone tool use in nonhuman primates and hominins.