986 research outputs found
Research qPCR Method for Engraftment Monitoring: A 6-Year Review of Proficiency Testing Results
The viability of Sphaeridiotrema pseudoglobulus (Digenea) eggs following cold water storage as a possible overwintering strategy
Sphaeridiotrema pseudoglobulus is a digenean parasite believed to be involved in a yearly fall die-off of ducks in QuĂ©bec, Canada. Hatching characteristics of eggs stored at 7°C for 0â28 weeks in the lab and following maintenance overwinter in a lake are described. The hatching success of eggs stored for 4â28 weeks remained constant (71â81 %) but slightly less than that observed in fresh eggs (90%). The hatching success of eggs kept overwinter under natural conditions did not differ from that of eggs stored an equivalent length of time in the lab at 7°C (74·7 and 75·8%, respectively). With the exception of fresh eggs (17·7 days), the mean hatch time of eggs steadily decreased with increased storage time (18·9 days following 4 weeks storage to 11·4 days at 28 weeks storage) due to a slow embryonation of the eggs at 7°C. Hatching characteristics of a subsample of eggs incubated at 10, 15 and 20°C were compared and the embryonation rate was found to increase with incubation temperature. The majority of eggs stored at 10°C embryonated but failed to hatch. When their incubation temperature was raised to 15°C, a further 46% hatched within the following week. The survivorship functions of miracidia hatching from eggs stored for 8, 12, 16 and 20 weeks differed but the mean expected life-span of the miracidia did not decline with increasing storage time as expected. The results of these experiments are discussed in relation to the potential importance of overwintered eggs in the development of the infective pool of metacercariae
Transmission of Cyclocoelum mutabile (Digenea) to snails: the influence of temperature on the egg and miracidium
This study examined the survival and hatching dynamics of eggs of the digenean Cyclocoelum mutabile and the survivorship and infectivity of the miracidia under different temperature regimes. Hatching did not occur at or below 12 °C. Hatching success was similar at 14, 16, and 20 °C (69â73%). Two peaks in hatching were seen. Most eggs hatched within 12 h following immersion in water; a smaller hatching peak occurred about 24 h later. Storing eggs at 12 °C for up to 4 weeks prior to raising the incubation temperature to 14 °C had no effect on hatching success. However, hatching success was dependent on the source of the eggs. Between 62 and 71% of the eggs from faeces and 90â98% of the eggs dissected from flukes hatched under the same protocol. Miracidia hatching from eggs stored for 0â7 weeks at 7 °C prior to hatching at 14 °C did not differ in their infectivity to snails (75â86%). The survivorship of miracidia was higher at lower temperatures and when they were obtained from eggs dissected from the fluke. The longer survival and prolonged infectivity of miracidia at lower temperatures produced the highest transmission efficiency at 14 °C. These results are discussed in relation to the seasonal transmission and ecology of the fluke
In vivo and in vitro studies on the viability and the infectivity to coots, Fulica americana, of Cyclocoelum mutabile metacercariae from three species of snails
The host response to and the viability and infectivity of metacercariae of Cyclocoelum mutabile were examined in three species of pulmonate snails, Stagnicola elodes, Gyraulus parvus, and Promenetus exacuous. Host response was generally similar among snail species at 8 weeks post infection. Host responses increased with age of infection in S. elodes. There was no difference in the excystment success of metacercariae from each species at 8 weeks post infection. The mean excystment time in vitro was greater for metacercariae from S. elodes than for those from either G. parvus or P. exacuous at 8 weeks post infection. There were no differences in either excystment success or mean excystment time of metacercariae from 5-, 8-, and 30-week-old infections from S. elodes. The mean infection success of metacercariae from S. elodes was lower than that of metacercariae from G. parvus and P. exacuous in juvenile coots. Adult coots were less susceptible to infection than juveniles. There was no difference in the infection levels established in naive and previously infected adult coots
Boarfish (Capros aper) protein hydrolysate has potent insulinotropic and GLP-1 secretory activity in vitro and acute glucose lowering effects in mice.
RBM5 Is a Male Germ Cell Splicing Factor and Is Required for Spermatid Differentiation and Male Fertility
Alternative splicing of precursor messenger RNA (pre-mRNA) is common in mammalian cells and enables the production of multiple gene products from a single gene, thus increasing transcriptome and proteome diversity. Disturbance of splicing regulation is associated with many human diseases; however, key splicing factors that control tissue-specific alternative splicing remain largely undefined. In an unbiased genetic screen for essential male fertility genes in the mouse, we identified the RNA binding protein RBM5 (RNA binding motif 5) as an essential regulator of haploid male germ cell pre-mRNA splicing and fertility. Mice carrying a missense mutation (R263P) in the second RNA recognition motif (RRM) of RBM5 exhibited spermatid differentiation arrest, germ cell sloughing and apoptosis, which ultimately led to azoospermia (no sperm in the ejaculate) and male sterility. Molecular modelling suggested that the R263P mutation resulted in compromised mRNA binding. Within the adult mouse testis, RBM5 localises to somatic and germ cells including spermatogonia, spermatocytes and round spermatids. Through the use of RNA pull down coupled with microarrays, we identified 11 round spermatid-expressed mRNAs as putative RBM5 targets. Importantly, the R263P mutation affected pre-mRNA splicing and resulted in a shift in the isoform ratios, or the production of novel spliced transcripts, of most targets. Microarray analysis of isolated round spermatids suggests that altered splicing of RBM5 target pre-mRNAs affected expression of genes in several pathways, including those implicated in germ cell adhesion, spermatid head shaping, and acrosome and tail formation. In summary, our findings reveal a critical role for RBM5 as a pre-mRNA splicing regulator in round spermatids and male fertility. Our findings also suggest that the second RRM of RBM5 is pivotal for appropriate pre-mRNA splicing.This work was supported by grants from the National Health and Medical Research Council (NHMRC) to DJ (#606503); the Australian Research Council (ARC) to MKO and CJO; the New South Wales Cancer Council, Cancer Institute New South Wales, Banque Nationale de Paris-Paribas Australia and New Zealand, RT Hall Trust, and the National Breast Cancer Foundation to CJO. DJ was an NHMRC Peter Doherty Postdoctoral Fellow (#384297). MKO and CJO are NHMRC Senior Research Fellows (#545805, #481310). CCG is an NHMRC Australia Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Protein hydrolysates from boarfish (Capros aper) and Atlantic salmon (Salmo salar) skin gelatin improve metabolic control in genetically obese diabetic (ob/ob) mice
There is increasing interest in dietary protein for management of Type 2 diabetes mellitus (T2DM) and obesity. The effects of twice-daily oral administration of a salmon skin gelatin hydrolysate (SSGH, 50 mg/kg), boarfish protein hydrolysate (BPH, (50 mg/kg), metformin (200 mg/kg), or saline control, were investigated in ob/ob mice. Non-fasting blood glucose was significantly reduced with SSGH (p < 0.01), BPH (p < 0.001) and metformin (p < 0.001), which were reflected in reductions in glycated haemoglobin (HbA1c) (p < 0.001, p < 0.01 and p < 0.01, respectively). Responses to oral and intraperitoneal glucose tolerance were improved (p < 0.05â0.01), as well as circulating plasma lipid profiles (p < 0.05â0.001). Chronic BPH treatment increased circulating plasma insulin (p < 0.01), whereas SSGH improved insulin sensitivity (p < 0.05), versus respective controls. All treatments significantly reduced energy intake (p < 0.05â0.001) versus (ob/ob) controls, without affecting overall bodyweight. These findings suggest that fish hydrolysates mediate potent anti-diabetic actions similar to metformin and might be suitable for the management and prevention of T2DM
The rapid response of the Canada Basin to climate forcing : from bellwether to alarm bells
Author Posting. © Oceanography Society, 2011. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 24 no. 3 (2011): 146â159, doi:10.5670/oceanog.2011.66.Sea ice extent in the Arctic Ocean diminished significantly during the first decade of the 2000s, most particularly in the Canada Basin where the loss of both multiyear and first-year ice was greater than in the other three subbasins. Using data collected during basin-wide surveys conducted from 2003â2010 together with data collected during the 1990s and 2000s at one station in the southern Canada Basin, we investigate the response of the Canada Basin water column to this significant decrease in ice cover. Changes were evident from the surface down to the Atlantic layer: some changes were the result of Beaufort Gyre forcing on regional processes, others were the result of Arctic Ocean atmospheric forcing on a hemispheric scale and large-scale advection. These changes have troubling consequences for the ecosystem.We acknowledge support from Fisheries
and Oceans Canada, the US National
Science Foundation Office of Polar
Programs (grant OPP-0424864), and
the Canadian International Polar Year
office
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