Showing papers by "Animal Research Institute published in 2006"

An approach to revealing blood fluke life cycles, taxonomy, and diversity: provision of key reference data including dna sequence from single life cycle stages

Abstract: Revealing diversity among extant blood flukes, and the patterns of relationships among them, has been hindered by the difficulty of determining if specimens described from different life cycle stages, hosts, geographic localities, and times represent the same or different species. Persistent collection of all available life cycle stages and provision of exact collection localities, host identification, reference DNA sequences for the parasite, and voucher specimens eventually will provide the framework needed to piece together individual life cycles and facilitate reconciliation with classical taxonomic descriptions, including those based on single life cycle stages. It also provides a means to document unique or rare species that might only ever be recovered from a single life cycle stage. With an emphasis on the value of new information from field collections of any available life cycle stages, here we provide data for several blood fluke cercariae from freshwater snails from Kenya, Uganda, and Australia. Similar data are provided for adult worms of Macrobilharzia macrobilharzia and miracidia of Bivitellobilharzia nairi. Some schistosome and sanguinicolid cercariae that we recovered have peculiar morphological features, and our phylogenetic analyses (18S and 28S rDNA and mtDNA CO1) suggest that 2 of the new schistosome specimens likely represent previously unknown lineages. Our results also provide new insights into 2 of the 4 remaining schistosome genera yet to be extensively characterized with respect to their position in molecular phylogenies, Macrobilharzia and Bivitellobilharzia. The accessibility of each life cycle stage is likely to vary dramatically from one parasite species to the next, and our examples validate the potential usefulness of information gleaned from even one such stage, whatever it might be.

C2GnT-M is downregulated in colorectal cancer and its re-expression causes growth inhibition of colon cancer cells.

Abstract: Changes in carbohydrates on the cell surface are associated with tumor malignancy. The mucin-type core 2 beta-1,6-N-acetylglucosaminyltransferase (C2GnT-M) is highly expressed in the gastrointestinal tract and catalyses the formation of core 2, core 4, and blood group I branches on O-glycans. In the present study, we evaluated the role of C2GnT-M in colorectal cancer. C2GnT-M downexpression was observed in 73.6% of the primary tumors from colorectal cancer patients (39 of 53) analysed by cancer profiling array. Consistently, the majority of colon cancer cell lines and primary colon tumors expressed lower levels of C2GnT-M than did normal colon tissues by RT-PCR. HCT116 cells stably transfected with C2GnT-M inhibited expression of the core 1 structure, Galbeta1,3GalNAcalpha1-Ser/Thr, on the cell surface. Moreover, C2GnT-M expression suppressed cell adhesion, motility, and invasion as well as colony formation ability. The growth of C2GnT-M-transfected HCT116 and SW480 cells was dramatically suppressed, and the cell death induced by C2GnT-M was demonstrated by an increase in the annexin V-positive cells. Interestingly, C2GnT-M inhibited cell adhesion to collagen IV and fibronectin, and decreased tyrosine phosphorylation of paxillin, indicating that the changes in cancer behavior may be partly mediated by integrin-signaling pathways. Tumor growth in vivo was also significantly suppressed by C2GnT-M in the xenografts of nude mice. These results demonstrate that C2GnT-M is frequently downregulated in colorectal cancer and suppresses colon cancer cell growth.

Variable growth rates of the tropical estuarine fish barramundi Lates calcarifer (Bloch) under different freshwater flow conditions

Abstract: Relationships between freshwater flows and growth rates of the opportunistic predatory finfish barramundi Lates calcarifer in a dry tropical estuary were examined using data from a long-term tag-recapture programme. Lagged effects were not investigated. After accounting for length at release, time at liberty and seasonal variation (e.g. winter, spring, summer and autumn), growth rates were significantly and positively related to fresh water flowing to the estuary. Effects were present at relatively low levels of freshwater flow (i.e. 2.15 m3 s-1, the 5th percentile of the mean flow rate experienced by fish in the study during time at liberty). The analysis, although correlative, provides quantitative evidence to support the hypothesis that freshwater flows are important in driving the productivity of estuaries and can improve growth of species high in the trophic chain.

Structural studies of biological membranes: the structure of myelin.

Abstract: The existence of a high degree of molecular organization in subcellular biological structures is no longer in doubt. The problem is rather to determine what intermolecular relationships are responsible for the remarkable properties observed. Most of the forces holding the component molecules together are physical forces of cohesion which are highly distance-specific. Hence precise configurational relationships must exist for such forces to be effective in maintaining the structural and functional integrity of biological structures, and furthermore, to insure the dimensional consistency of substructural elements, the specificity of the related enzymic and immunochemical reactions, and the order revealed by X-ray diffraction. Unequivocal, direct measurements cannot be made at the molecular level.' The problem must be solved by studying arrangements obtained with scaled up models of the component molecules, assumed to represent the structures investigated. In this research, an important step consists in reducing the unlimited number of theoretically possible configurations such models can adopt. A further selection can then be made on the basis of intermolecular force estimations. This will eliminate such configurations and combinations of the component molecules as could not offer a high degree of structural stability. The fmal choice should verify all pertinent data available for the structure under study and best predict its known properties. At the present time, the likelihood of such an ambitious program to be carried out to completion is remote in the case of most subcellular structures. Recent studies have indicated, however, that partial solutions could be obtained in instances where extensive electromicroscopic observations have been made, where detailed analytical and structural data of molecular components are available and above all, where X-ray diffraction studies have supplied key structural parameters. This is the case of the myelin sheath of nerve. In a previous article, the author has presented evidence for a proposed arrangement of the lipids in myelin.' The present report summarizes this concept and describes a possible configuration of the protein component. The importance of myelin as a functional structure of the nervous system need not be emphasized. On the other hand, it follows from the mechanism of myelinization described by Gereq3 that the unit layer of myelin is made of two layers of the Schwann cell membrane joined by their outer surfaces. It is therefore an excellent material for the study of cell membranes which it represents in a highly concentrated, readily accessible form. The chemical analysis of membrane systems has brought us in some cases detailed information concerning the nature and relative amounts of the numerous molecular species which they contain. All we know with certainty about the structure of membranes is that they consist of a sandwich of two lipid layers between parallel layers of hydrated protein.' In the case of myelin, we have information concerning the relative position of the lipid leaflet in the unit layer of myelin and on its thickness. This was obtained through

Free-range Village Chickens on the Accra Plains, Ghana:Their Husbandry and Productivity

Abstract: A cross-sectional[4pc] survey investigating husbandry and productivity of free-range village chickens was carried out in four administrative districts within 60km of Accra. Responses were provided by 101 men and 99 women. The mean (SD) household flock size was 28.7 (25.97) and the median was 20. The factors included in the final model investigating variance in flock size were sex of the respondent (p=0.011), administrative area (p=0.004), the numbers of members in the household (p=0.017) and the number of cattle, sheep and goats owned by the household (p=0.031). Chickens were owned by individual members of the household, but women and children were the predominant providers of care for chickens. All respondents described their chickens as scavengers that were provided with supplementary feed, and over 80% of respondents named maize as a supplementary food source. Approximately 50% of respondents claimed difficulty in providing supplementary feed, with the degree of difficulty varying between administrative areas (p<0.001). A majority of respondents (approximately 65%) claimed that their chickens laid 3–4 clutches of eggs per year. Over 70% of respondents estimated that each clutch contained 10–20 eggs, and approximately 70% of respondents estimated that 75% of the eggs hatched. Opinions on mortality varied, but 60% of men and 70% of women estimated that between 50% and 75% of both chicks and adult birds died each year. Approximately 80% of respondents named Newcastle disease as the most important health issue. The opportunities for and consequences of controlling Newcastle disease are discussed.

Development of a polymerase chain reaction procedure for detection and differentiation of duck and goose circovirus

Abstract: This article reports the complete nucleotide sequences of four duck circovirus (DuCV) isolates from sick ducks in Taiwan and development of a polymerase chain reaction (PCR) for detection and differentiation of goose circovirus (GoCV) and DuCV. Sequence comparison showed that Taiwanese DuCV isolates had 82.5%-83.8% nucleotide sequence identity to the German and North American DuCV isolates. This is the first report on the presence of DuCV and its associated diseases outside Germany. A PCR test was developed using a universal primer pair based on conserved sequences present in the genomes of GoCV and DuCV. This PCR test could detect and differentiate between GoCV and DuCV by the size of PCR product each virus produced (256 bp for GoCV and 228 bp for DuCV). Application of this PCR test to samples of bursa of Fabricius from sick birds in the field showed that 9 of 26 goose samples contained GoCV, while 13 of 34 duck samples contained DuCV. This PCR test could serve as a fast and sensitive method for detection and differentiation of DuCV and GoCV.

Validation of a competitive enzyme-linked immunosorbent assay for detection of antibodies against Babesia bovis.

Abstract: A previously developed competitive enzyme-linked immunosorbent assay (cELISA) based on a species-specific, broadly conserved, and tandemly repeated B-cell epitope within the C terminus of rhoptry-associated protein 1 of Babesia bovis was refined and validated for use internationally. Receiver operating characteristic analysis revealed an assay with a specificity and positive predictive value of 100% and a sensitivity of 91.1%, with various negative predictive values depending on the level of disease prevalence. The cELISA was distributed to four different laboratories, along with a reference set of 100 defined bovine sera, including known-positive, known-negative, and field samples. Pairwise concordances among the four laboratories ranged from 94% to 88%. Analysis of variance of the resulting optical densities and a test of homogeneity indicated no significant difference among the laboratories. Overall, the cELISA appears to have the attributes necessary for international application.

Effect of dried oregano leaves versus neomycin in treating newborn calves with colibacillosis.

Abstract: Treatment with neomycin (as a positive control) and dried oregano leaves on mortality, number of days scouring and severity of scours due to Escherichia coli were examined in 30 Holstein calves. Calves were assigned to one of the treatments following clinical signs of diarrhoea (i.e. faecal score >2), and treated either with an oral solution of neomycin sulphate, to provide 10 mg neomycin sulphate per kg calf body weight per 24 h, or dried oregano leaves, to provide 10 mg oregano essential oil per kg calf body weight per 24 h. The number of scouring days, severity of scouring and mortality rates were similar between the treatments. This study indicates that dried oregano leaves administered as an oral solution to calves with diarrhoea may be as effective in the treatment of colibacillosis as neomycin.

Survival of Campylobacter spp. in darkling beetles (Alphitobius diaperinus) and their larvae in Australia.

Abstract: Campylobacter infection is the most frequently reported notifiable food-borne disease in humans in Australia. Our studies investigated the persistence of Campylobacter spp. in or on darkling beetles (Alphitobius diaperinus) and their larvae. Our results in analyses with chickens confirm that, unless very short turnaround times are used (<72 h), beetles colonized in one production cycle (i.e., one batch of chickens) are most unlikely to still be colonized during the next cycle of chickens.

Free-range village chickens on the Accra Plains, Ghana: their contribution to households.

Abstract: A cross-sectional survey investigating the contribution of free-range village chickens to household economies was carried out in four administrative districts within 60km of Accra. Answers were provided by 101 men and 99 women. Nearly all respondents claimed to keep chickens for meat, with a far smaller percentage claiming to keep them for egg production. Over 80% of respondents kept chickens to supplement their incomes. The proportion of the flock eaten varied between administrative areas (p=0.009 and p=0.027), although this was possibly a consequence of differences in consumption patterns between occupation of the respondent, land area cultivated and flock size. The proportion of chickens sold varied as a result of differences in flock size (p=0.013), the proportion sold increasing with number of birds in the flock. Respondents generally agreed that chickens could be sold without difficulty. A majority of chicken sales were from the farm gate, directly to consumers or traders. Sales were on demand or when the owner needed money. Money from the sale was kept by the owner of the chicken and the money was spent on personal needs. The proportion of the flock sold varied between administrative areas (p=0.025) and occupation of the respondent (p=0.040). Respondents describing animal production as their main occupation tended to have greater reliance on chicken sales for their income. Consideration is given to estimating the offtake from the flock and the financial contribution to the household.

Effects of genetic and environmental factors on pre-weaning and post-weaning growth in West African crossbred sheep.

Abstract: Effects of genetic and environmental factors on pre-weaning and post-weaning growth were studied in West African crossbred sheep. Effects of lamb genotype (7/8 Sahelian–1/8 Djallonke, 3/4 Sahelian–1/4 Djallonke and 1/2 Sahelian–1/2 Djallonke; hereafter denoted 7/8Sa, 3/4Sa and 1/2Sa, respectively), parity, type of birth, sex of lamb and year-season of lambing on birth weight, weaning weight, 8-month weight and pre- and post-weaning growth rates were determined. At birth 7/8Sa and 3/4Sa lambs were heavier (p < 0.01) than 1/2Sa lambs. Lambs born to first-parity ewes were lighter (p < 0.01) at birth than lambs of older ewes. At weaning and 8 months of age, lambs born to fourth-parity ewes were heavier (p < 0.05) than those born to ewes of the other parities. Parity did not have any significant effects on pre-weaning growth rate. Lambs born in the rainy season of 2001 were significantly heavier at birth and at 8 months of age than those born in the dry season of 2001/02, but there was no difference between the two groups at weaning. Pre-weaning growth rate was significantly faster in lambs born in the dry season of 2001/02 but the reverse was true for post-weaning growth rate.

A comparison of the excretion rate of endogenous purine derivatives in the urine of Bos indicus and Bos taurus steers

Abstract: Estimates of microbial crude protein (MCP) production by ruminants, using a method based on the excretion of purine derivatives in urine, require an estimate of the excretion of endogenous purine derivatives (PD) by the animal. Current methods allocate a single value to all cattle. An experiment was carried out to compare the endogenous PD excretion in Bos taurus and high-content B. indicus ( hereafter, B. indicus) cattle. Five Holstein - Friesian ( B. taurus) and 5 Brahman (> 75% B. indicus) steers ( mean liveweight 326 +/- 3.0 kg) were used in a fasting study. Steers were fed a low-quality buffel grass (Cenchrus ciliaris; 59.4 g crude protein/kg dry matter) hay at estimated maintenance requirements for 19 days, after which hay intake was incrementally reduced for 2 days and the steers were fasted for 7 days. The excretion of PD in urine was measured daily for the last 6 days of the fasting period and the mean represented the daily endogenous PD excretion. Excretion of endogenous PD in the urine of B. indicus steers was less than half that of the B. taurus steers ( 190 mu mol/kg W-0.75. day v. 414 mu mol/kg W-0.75. day; combined s.e. 37.2 mu mol/kg W-0.75. day; P< 0.001). It was concluded that the use of a single value for endogenous PD excretion is inappropriate for use in MCP estimations and that subspecies-specific values would improve precision.

Registration of ICG 12991 Peanut Germplasm Line

Abstract: ICG 12991 is a short duration (90–110 d to maturation), drought-tolerant, spanish-type peanut (Arachis hypogaea L. subsp. fastigiata Waldron var. vulgaris Harz.) germplasm line (Reg. no. GP-122, PI 639691) with a high level of field resistance to groundnut rosette disease (Naidu et al., 1999a; Subrahmanyam et al., 2000). Groundnut rosette disease results from a synergism of three agents: Groundnut rosette assistor virus (GRAV, a luteovirus), Groundnut rosette virus (GRV, an umbravirus), and a satellite RNA (sat RNA) of GRV. ICG 12991 was originally collected from a farmer’s field in south India in 1988. In 1994, ICRISAT introduced ICG 12991 into Malawi for evaluation during a germplasm screening program for resistance to groundnut rosette disease and early leaf spot disease (caused by Cercospora arachidicola S. Hori). Subsequently, ICG 12991 was released in Malawi as ‘Baka’ in 2001 and in Uganda as ‘Serenut 4T’ in 2002, following extensive testing and distribution by the national programs of each country. Resistance to groundnut rosette disease in ICG 12991 is due to aphid resistance, not due to resistance to the virus complex (Naidu et al., 1999b).

Genetic variation and responses in reproductive performance of sows in lines selected for growth rate under restricted feeding

Abstract: The objective of this study was to examine genetic changes in reproduction traits in sows (total number born (TNB), number born alive (NBA), average piglet birth weight (ABW) and number of piglets weaned (NW), body weight prior to mating (MW), gestation length (GL) and daily food intake during lactation (DFI)) in lines of Large White pigs divergently selected over 4 years for high and low post-weaning growth rate on a restricted ration. Heritabilities and repeatabilities of the reproduction traits were also determined. The analyses were carried out on 913 litter records using average information-restricted maximum likelihood method applied to single trait animal models. Estimates of heritability for most traits were small, except for ABW (0·33) and MW (0·35). Estimates of repeatability were slightly higher than those of heritability for TNB, NBA and NW, but they were almost identical for ABW, MW, GL and DFI. After 4 years of selection, the high growth line sows had significantly heavier body weight prior to mating and produced significantly more piglets born alive with heavier average birth weight than the low line sows. There were, however, no statistical differences between the selected lines in TNB or NW. The lower food intake of high relative to low line sows during lactation was not significant, indicating that daily food intake differences found between grower pigs in the high and low lines (2·71 v. 2·76 kg/day, s.e.d. 0·024) on ad libitum feeding were not fully expressed in lactating sows. It is concluded that selection for growth rate on the restricted ration resulted in beneficial effects on important measures of reproductive performance of the sows.

Microbial contamination of smoked Anchovis

Abstract: Smoked Anchovis spp. ( Engraulis encrasicholus Linndeus) obtained from Senya Beraku (a major fishing centre), Kasoa (a marketing centre), and the Animal Research Institute Feedmill (feed-processing centre) was assessed for microbial contamination, using total viable count technique (pour plate method) and culture techniques. Sixty samples were aseptically and randomly selected into sterile universal bottles from the three study areas, with 20 samples from each study area. Total viable count ranged from 1 × 10 5 to 4.9 × 10 7 , 3.4 × 10 5 to 2.0 × 10 8 , and 6.5 × 10 5 to 3.1 × 10 8 for Kasoa, Senya Beraku and Feedmill, respectively. A total of 139 isolates made up of 84 bacteria and 55 fungi were isolated. The 84 bacteria isolates belonged to 11 genera: Streptococcus, Staphylococcus, Micrococcus, Salmonella, Enterobacter, Escherichia, Pasteurella, Pseudomonas, Bacillus, Listeria , and Aeromonas . The 55 fungi isolates belonged to five genera: Aspergillus, Trichoderma, Rhizopus, Penicillium , and Mucor . Since most of the organisms isolated may cause disease in man and animal, it is suggested that processing, handling, and storage of fish be improved to reduce contamination. Ghana Journal of Agricultural Science Vol. 37 2004: 69-74

The hDAF exogene protects swine endothelial and peripheral blood mononuclear cells from xenoreactive antibody mediated cytotoxicity in hDAF transgenic pigs.

Abstract: Xenoreactive antibody-induced complement activation and cytotoxicity poses a major obstracle to xenograft survival in humans. Previously, we have generated transgenic pigs carrying the hDAF exogene to help overcome this problem. In this study, we examined whether the hDAF exogene in various swine cells shows an equally protective effect for the complement-mediated cytotoxicity induced by human xenoreactive antibodies. Pig peripheral blood mononuclear cells (PBMCs) and aortic endothelial cells (PAECs) were used as targets. Fresh human serum was harvested from a single healthy human donor as the source of human xenoreactive antibodies and complement. The target cells cocultured with medium containing various concentrations of human serum for 24 hours were evaluated using the 3-[4,5-dimethylthiaolyl]-2,5-diphenyl-tetrazolium bromide assay for cellular viability. We observed that xenoreactive antibody plus human complement-mediated cellular cytoxicity dose-dependently correlated with the concentration of human serum in the culture medium. As compared with the PBMCs from the normal pigs, PBMCs from hDAF transgenic pigs showed significantly better survival after treatment with human serum (P < .05). Similarly, the survival of PAECs from the hDAF transgenic pig were also significantly higher than that from normal pigs (P < .05). Our data demonstrated a protective effect from human xenoreactive antibodies and complement-mediated cytoxicity of hDAF exogenes in pig PBMCs and PAECs. These observations support the clinical value of the hDAF transgenic pig as an organ donor in xenotransplantation.

Fasting ketosis in the pregnant guinea pig.

Abstract: Ketosis by definition refers to an accumulation of acetoacetate, B-hydroxybutyrat,e and acetone in body fluids. Although ketone bodies are most commonly measured in blood or urine they are distributed throughout the body and may readily be detected in secretions such as milk. The term ketosis is applied to a number of different clinical conditions, i.e., diabetic ketosis, fasting ketosis, ketosis of high fat intake and ruminant ketosis (bovine and ovine, the latter is commonly referred to as “pregnancy toxemia”). All of these are characterized by hyperketonemia and ketonuria, however, there is at the present time no basis for assuming a common metabolic defect. Pregnancy toxemia of ewes and ketosis of dairy cattle are of primary interest to agriculture because of widespread distribution and resulting economic losses. Bergnian and Sellers‘ recently reported t,hat fasting ketosis of pregnant guinea pigs closely resembled ovine pregnancy toxemia; this suggested the possibility of studying experimental, non-diabetic, hypoglycemic ketosis in a laboratory animal. Although the ketotic syndrome in guinea pigs in many respects resembles that in pregnant ewes, obviously the details of this relationship have not been clarified and further elaboration is required. The present investigation was carried out with ketotic and control guinea pigs divided into the following groups: ketotic (K), pregnant fed (PF), nonpregnant fed (NPF), nonpregnant starved (NPS) and young (Y> (300 g).

A Study on the Time of Ovicidal Effect of Some Anthelmintics in Djallonke Sheep and Its Implication for the Control of Parasitic Helminth Infections

Abstract: The time lag between the administration of five different anthelmintics and the exertion of their ovicidal effect on worm eggs was monitored in five groups of Djallonke sheep. In this experiment, all the animals in all treated groups and an untreated control group were grazed together. Worm egg output and the number of infective strongylate nematode larvae (L3s) recovered from fecal cultures from each group were observed every four hours for 72 h. The earliest time observed for the occurrence of ovicidal effect resulting in the absence of L3s in fecal cultures was 8 h after the administration of the anthelmintics. However, this time was not the same for all the anthelmintics. The implication of the results are discussed in relation to its application for worm control.