Toxicokinetics of mercury in blood compartments and hair of fish-fed sled dogs     

Camilla L Lieske  Sara K Moses  Judith M Castellini  Jessica Klejka  Karsten Hueffer  Todd M O'Hara 《Acta veterinaria Scandinavica》2011,53(1):66

Background

Understanding mercury (Hg) distribution in blood and the importance of hair as an excretory pathway is critical for evaluating risk from long term dietary Hg exposure. The major objective of this study was to characterize changes in total Hg concentrations in specific blood compartments and hair over time due to long term piscivory.

Methods

Eight sled dogs (Canis lupus familiaris) were fed either a fish and kibble diet (n = 4), or a fish-free control diet (n = 4) for 12 weeks. Concentrations of Hg were monitored throughout the exposure period, and for 10 weeks post exposure, until Hg concentrations in all blood compartments of one of the exposed dogs dropped below detection limit. Additionally, foreleg hair was sampled during acclimation and weeks 0 and 12.

Results

Hg was detected primarily in whole blood and packed cells, although it was sporadically detected at low concentrations in plasma and serum in two of the fish fed dogs. Dogs ingested an estimated average of 13.4 ± 0.58 μg Hg per kg body weight per day. Hg was detectable in whole blood and packed cells within a week of exposure. Detected concentrations continued to rise until plateauing at approximately 3-6 weeks of exposure at a mean of 9.2 ± 1.97 ng/g (ppb) in whole blood. Hg concentration decreased post exposure following 1st order elimination. The mean half-life (t_1/2) in whole blood for Hg was 7 weeks. Mean Hg in hair for the fish-fed dogs at week 12 was 540 ± 111 ppb and was significantly greater (about 7-fold) than the Hg hair concentration for the control dogs. The hair to blood ratio for Hg in fish-fed dogs was 59.0 ± 7.6:1.

Conclusions

This study found the sled dog model to be an effective method for investigating and characterizing blood Hg distribution (whole blood, serum, plasma, packed cells) and toxicokinetics associated with a piscivorous diet, especially for Hg-exposed fur bearing mammals (such as polar bears). Although hair excretion and hair to blood Hg ratios were not similar to human concentrations and ratios, the sled dog toxicokinetics of Hg in blood, was more similar to that of humans than traditional laboratory animals (such as the rat).  相似文献   

Evaluating persistence and its predictors in a West African carnivore community     

A. Cole Burton  Moses K. Sam  David G. Kpelle  Cletus Balangtaa  Eric B. Buedi  Justin S. Brashares 《Biological conservation》2011,144(9):2344-2353

Carnivore extinctions frequently have cascading impacts through an ecosystem, so effective management of ecological communities requires an understanding of carnivore vulnerability. This has been hindered by the elusive nature of many carnivores, as well as a disproportionate focus on large-bodied species and particular geographic regions. We use multiple survey methods and a hierarchical multi-species occupancy model accounting for imperfect detection to assess extinction risk across the entire carnivore community in Ghana’s Mole National Park, a poorly studied West African savanna ecosystem. Only 9 of 16 historically occurring carnivore species were detected in a camera-trap survey covering 253 stations deployed for 5469 trap days between October 2006 and January 2009, and our occupancy model indicated low overall likelihoods of false absence despite low per-survey probabilities of detection. Concurrent sign, call-in, and village surveys, as well as long-term law enforcement patrol records, provided more equivocal evidence of carnivore occurrence but supported the conclusion that many carnivores have declined and are likely functionally or fully extirpated from the park, including the top predator, lion (Panthera leo). Contrary to expectation, variation in carnivore persistence was not explained by ecological or life-history traits such as body size, home range size or fecundity, thus raising questions about the predictability of carnivore community disassembly. Our results imply an urgent need for new initiatives to better protect and restore West Africa’s embattled carnivore populations, and they highlight a broader need for more empirical study of the response of entire carnivore communities to anthropogenic impact.  相似文献   

Performance of purebred and crossbred progeny of White Leghorn and New Hampshire sires     

M. Taran  Elsa Gabriel  E. Moses  M. Soller 《British poultry science》1972,13(4):331-339

Data from a reciprocal recurrent selection (RRS) programme involving a White Leghorn and a New Hampshire flock were analysed to determine whether there were genetic differences in the purebred population that came to expression primarily in the crossbred progeny. The RRS programme had been in use for four years. The White Leghorn flock had previously been the subject of long‐continued and intensive family selection. The New Hampshire flock was less highly selected. Egg number, egg weight and body weight were the primary traits under selection. Each year the programme involved about 10 sires and 80 females of each breed, and about 400 offspring of each type of cross.

The overall economic value of the crossbreds consistently exceeded the mid‐parent mean, the difference increased steadily during the RRS programme. Heritabilities of the various traits were higher when calculated on the basis of crossbred offspring than when calculated on the basis of purebred offspring. For egg production in the White Leghorns there was a fairly low correlation between purebred and crossbred offspring of the same male. For other traits in both breeds the correlation between purebred and crossbred offspring was moderately high. There was a significant interaction between males and breed of females for all traits and breeds, except for egg number in the New Hampshire. These results are consistent with the notion that there were genetic differences between the purebred males (particularly the White Leghorn males) that affected the production characteristics of their crossbred progeny differently than their purebred progeny.  相似文献   

Structural biology. The p75 NGF receptor exposed     

Zampieri N  Chao MV 《Science (New York, N.Y.)》2004,304(5672):833-834

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Phytase activity in extracts of flour and bran from wheat cultivars: enhanced extractability with β-glucanase and endo-xylanase     

Moses Okot-Kotber  Kwon-Joong Yong  Katherine Bagorogoza  Allan Liavoga 《Journal of Cereal Science》2003,38(3):307-315

Phytase (EC 3.1.3.8) hydrolyzes phytic acid to myo-inositol and inorganic phosphate through intermediate myo-inositol phosphates. Microbial phytase has been employed to minimize the negative effects of phytic acid in cereal-based feeds, however, other sources such as wheat, would be natural alternatives. Investigations were therefore carried out to determine the levels of phytase activity in various cultivars and how the extraction of the enzyme may be enhanced using buffers fortified with glycanases. We screened 23 cultivars and the results showed that bran from hard white wheat cultivars had relatively lower levels of activity, ranging from about 1.5 to about 2.5 FTU/g bran, whereas hard red wheat cultivars had much higher levels, ranging from approximately 2 to 5.5 FTU/g bran. These levels were greatly enhanced, up to 5-fold, when extraction buffer contained a commercial preparation consisting of β-glucanase (EC 3.2.1.6) and endo-xylanase (EC 3.2.1.8) (Natugrain) (opt 1%) from BASF. The effect of glycanases was concentration and cultivar dependent, but not significantly influenced by temperature exposure of mixtures of samples with extraction buffers prior to extraction. Relative increases were more substantial in hard white than in hard red wheat cultivars. The additional value of supplementing grain-based diets with glycanases for monogastric animals is discussed.  相似文献   

Antidiuretic response of a horse affected with pituitary pars intermedia dysfunction to desmopressin acetate     

M. E. Moses  P. J. Johnson  N. T. Messer  D. A. Wilson 《Equine Veterinary Education》2013,25(3):111-115

Central diabetes insipidus (DI) was diagnosed in a 20‐year‐old American Quarter Horse gelding that was concomitantly affected with pituitary pars intermedia dysfunction (PPID). The diagnosis of DI was supported by a positive response to administered desmopressin acetate. Diagnosis of PPID was supported by physical appearance and elevated plasma adrenocorticotropic hormone concentration following domperidone administration. The horse's physical condition improved following treatment with pergolide but long‐term treatment with desmopressin was not undertaken and severe polyuria and polydipsia persisted. Desmopressin acetate appears to be useful for the diagnosis of DI in mature horses concomitantly affected with PPID.  相似文献   

Assessing the effects of subtropical forest fragmentation on leaf nitrogen distribution using remote sensing data     

Moses Azong Cho  Abel Ramoelo  Pravesh Debba  Onisimo Mutanga  Renaud Mathieu  Heidi van Deventer  Nomzamo Ndlovu 《Landscape Ecology》2013,28(8):1479-1491

Subtropical forest loss resulting from conversion of forest to other land-cover types such as grassland, secondary forest, subsistence crop farms and small forest patches affects leaf nitrogen (N) stocks in the landscape. This study explores the utility of new remote sensing tools to model the spatial distribution of leaf N concentration in a forested landscape undergoing deforestation in KwaZulu-Natal, South Africa. Leaf N was mapped using models developed from RapidEye imagery; a relatively new space-borne multispectral sensor. RapidEye consists of five spectral bands in the visible to near infra-red (NIR) and has a spatial resolution of 5 m. MERIS terrestrial chlorophyll index derived from the RapidEye explained 50 % of the variance in leaf N across different land-cover types with a model standard error of prediction of 29 % (i.e. of the observed mean leaf N) when assessed on an independent test data. The results showed that indigenous forest fragmentation leads to significant losses in leaf N as most of the land-cover types (e.g. grasslands and subsistence farmlands) resulting from forest degradation showed lower leaf N when compared to the original indigenous forest. Further analysis of the spatial variation of leaf N revealed an autocorrelation distance of about 50 m for leaf N in the fragmented landscape, a scale corresponding to the average dimension of subsistence fields (2,781 m²) in the region. The availability of new multispectral sensors such as RapidEye thus, moves remote sensing closer to widespread monitoring of the effect of tropical forest degradation on leaf N distribution.  相似文献   

Adaptive values of wild × cultivated sorghum (<Emphasis Type="Italic">Sorghum bicolor</Emphasis> (L.) Moench) hybrids in generations F<Subscript>1</Subscript>, F<Subscript>2</Subscript>, and F<Subscript>3</Subscript>     

Moses M. Muraya  Hartwig H. Geiger  Fabrice Sagnard  Lassana Toure  Pierre C. S. Traore  Sabine Togola  Santie de Villiers  Heiko K. Parzies 《Genetic Resources and Crop Evolution》2012,59(1):83-93

Gene flow between cultivated and their wild relatives is one of the main ecological concerns associated with the introduction genetically modified (GM) cultivars. GM sorghum cultivar has been developed and its commercial production may be possible in the near future. The rate of gene flow depends on the fitness of wild × cultivated sorghum hybrids. The study aimed at estimating adaptive values of wild × cultivated sorghum hybrids in generations F₁, F₂, and F₃ compared to their parents. Artificial crosses of four wild sorghums, five cultivated sorghums, and two male sterile lines were made to produce the F₁ generation, which were advanced to F₂ and F₃. Each hybrid generation and their respective parents were evaluated for their adaptive value at two sites in a randomised complete block design with seven replicates. The resulting progenies did not show serious fitness penalties. Some hybrids were as fit as their respective wild parents and no consistent differences exist between the three generations studied. Thus, the resultant wild × cultivated hybrids may act as avenue for introgression.  相似文献   

Pigeonpea breeding in eastern and southern Africa: challenges and opportunities          下载免费PDF全文

Seleman R. Kaoneka  Rachit K. Saxena  Said N. Silim  Damaris A. Odeny  Nadigatla Veera Prabha Rama Ganga Rao  Hussein A. Shimelis  Moses Siambi  Rajeev K. Varshney 《Plant Breeding》2016,135(2):148-154

Pigeonpea (Cajanus cajan [L.] Millspaugh) is an important multipurpose grain legume crop primarily grown in tropical and subtropical areas of Asia, Africa and Latin America. In Africa, the crop is grown for several purposes including food security, income generation, livestock feed and in agroforestry. Production in Eastern and Southern Africa (ESA) is however faced with many challenges including limited use of high‐yielding cultivars, diseases and pests, drought, under‐investment in research and lack of scientific expertise. The aim of this review is to highlight the challenges facing pigeonpea breeding research in ESA and the existing opportunities for improving the overall pigeonpea subsector in the region. We discuss the potential of the recently available pigeonpea genomic resources for accelerated molecular breeding, the prospects for conventional breeding and commercial hybrid pigeonpea, and the relevant seed policies, among others, which are viewed as opportunities to enhance pigeonpea productivity.  相似文献   

Cryptosporidium species detected in calves and cattle in Dagoretti,Nairobi, Kenya     

Kang&#;ethe  Erastus K.  Mulinge  Erastus K.  Skilton  Robert A.  Njahira  Moses  Monda  Joseph G.  Nyongesa  Concepta  Mbae  Cecilia K.  Kamwati  Stanley K. 《Tropical animal health and production》2012,44(1):25-31

A total of 1,734 cattle faecal samples from 296 dairy-keeping households were collected from urban settings in Nairobi, Kenya. Modified Ziehl–Neelsen staining method and an immunofluorescence assay were used to identify those samples with Cryptosporidium oocyst infection. Oocysts from positive faecal samples were isolated by Sheather's sucrose flotation method and picked from the concentrate using cover slips. Genomic DNA was extracted from 124 of the faecal samples that were positive for Cryptosporidium and was used as template for nested PCR of the 18S rRNA gene. Twenty-five samples (20 %) were PCR-positive for Cryptosporidium, and 24 of the PCR products were successfully cloned and sequenced. Sequence and phylogenetic analysis identified 17 samples (68 %) as Cryptosporidium parvum-like, four samples (16 %) as Cryptosporidium ryanae, three samples (12 %) as Cryptosporidium andersoni and one sample (4 %) as Cryptosporidium hominis. To the best of our knowledge, this is the first genotyping study to report C. parvum-like, C. andersoni and C. hominis in cattle from Kenya. The results of this study show Cryptosporidium infections in calves and cattle may be potential zoonotic reservoirs of the parasite that infects humans.  相似文献