bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extent of hepatitis E virus elimination is affected by stabilizers present in plasma products and pore size of nanofilters
Authors: Yunoki M. , Yamamoto S. , Tanaka H. , Nishigaki H. , Tanaka Y. , Nishida A. , Adan‐Kubo J. , Tsujikawa M. , Hattori S. , Urayama T. , Yoshikawa M. , Yamamoto I. , Hagiwara K. , Ikuta K. 
Published: July 2008

Background and Objective  To investigate the physico‐chemical properties of hepatitis E virus (HEV) with regard to inactivation/removal, we have studied four isolates with respect to sensitivity to heat during liquid/dry‐heating as well as removal by nanofiltration.Materials and Methods  Hepatitis E virus in an albumin solution or phosphate‐buffered saline (PBS) was liquid‐heated at 60°C for a preset time. HEV in a freeze‐dried fibrinogen containing stabilizers was also dry‐heated at 60 or 80°C for a preset time. In addition, to clarify the removal of HEV, the purified virus in PBS was filtered using several types of virus‐removal filter (nanofilters) that have different pore sizes. HEV infectivity or genome equivalents before and after the treatments were assayed by a semiquantitative cell‐based infectivity assay or quantitative polymerase chain reaction assay, respectively.Results  Hepatitis E virus isolates in albumin solutions were inactivated slowly at 60°C for 5 h and the resultant log reduction factor (LRF) was from 1·0 to ≥ 2·2, whereas the virus in PBS was inactivated quickly to below the detection limit and the LRF was ≥ 2·4 to ≥ 3·7. The virus in a freeze dried fibrinogen containing trisodium citrate dihydrate and l‐arginine hydrochloride as stabilizers was inactivated slowly and the LRF was 2·0 and 3·0, respectively, of the 72 h at 60°C, but inactivated to below the detection limit within 24 h at 80°C with an LRF of ≥ 4·0. The virus in PBS was also confirmed as to be approximately 35 nm in diameter by nanofiltration. These results are useful for evaluating viral safety against HEV contamination in blood products.Conclusion  The sensitivity of HEV to heat was shown to vary greatly depending on the heating conditions. On the other hand, the HEV particles were completely removed using 20‐nm nanofilters. However, each inactivation/removal step should be carefully evaluated with respect to the HEV inactivation/removal capacity, which may be influenced by processing conditions such as the stabilizers used for blood products.
Sperm Quantity Explains Age‐Related Variation in Fertilization Success in the Hide Beetle
Authors: Hale Joshua M. , Elgar Mark A. , Jones Therésa M. 
Published: July 2008

AbstractAge‐related variation in sperm quality and quantity may have a dramatic impact on female fecundity and fertilization success. Despite this, the relationships between these parameters are rarely investigated. Moreover, studies exploring age‐related variation in male mating success generally fail to consider the entire lifespan of an individual male; instead they restrict analyses to a small number of defined age classes. As a consequence they are unable to assess the impact of early and late life history components on male reproductive success. In this study, we explore these questions using the hide beetle, Dermestes maculatus, a model species for investigating age‐related male mating success. We first employed a longitudinal design to explore whether patterns of sperm transfer and subsequent reproductive success varied over the reproductive lives of a cohort of males. Secondly, we investigated age‐related variation in sperm viability, a surrogate measure of sperm quality. Finally, we combined these data and assessed whether the observed patterns of sperm transfer were correlated with fertilization success. We found that the quantity of sperm varied with male age: the amount of sperm transferred to a female increased with male age until 9 wk and then started to decline. Similarly, female fecundity and fertilization success were related to male age: females mating with males when they were relatively young (1 wk) or relatively old (13 wk) suffered reductions in fecundity and fertilization. Our data suggest that fertilization success is driven at least in part by the quantity of sperm transferred during mating.
Smoke‐Water and a Smoke‐Isolated Butenolide Improve Germination and Seedling Vigour of Eragrostis tef (Zucc.) Trotter under High Temperature and Low Osmotic Potential
Authors: Ghebrehiwot H. M. , Kulkarni M. G. , Kirkman K. P. , Van Staden J. 
Published: July 2008

AbstractThe seeds of Eragrostis tef are often exposed to high temperatures and low water availability during unfavourable climatic conditions. This affects germination and seedling stand establishment of the crop. Smoke is currently widely studied for its stimulatory role in seed germination. The effect of smoke‐water and a smoke‐isolated butenolide was investigated on E. tef seed germination and seedling growth at different temperatures, light conditions and osmotic potentials. Treating E. tef seeds with smoke‐water and butenolide increased the percentage germination relative to the control at all tested temperatures. These treatments significantly improved seedling length and the vigour index at 25, 30, 35 and 40 and 30/15 °C. Smoke‐water and butenolide increased percentage imbibition from high to low osmotic potential. In comparison with the control, smoke‐water‐ and butenolide‐treated seeds of E. tef showed higher percentage germination with decreasing osmotic potential. Smoke‐water treatment exhibited significantly longer and more vigorous seedlings than the control between 0 and −0.30 MPa osmotic potential. The findings of this study suggest the possibility of using smoke treatments for minimizing E. tef seedling losses at elevated temperatures and water stress.
Sex pheromones in three Bradysia species (Dipt., Sciaridae): novel bioassays with female body extracts and fractions
Authors: Frank J. , Dettner K. 
Published: July 2008

AbstractFemales of the fungus gnat species Bradysia difformis, Bradysia optata and Bradysia tilicola are able to produce sexual attractants. In males, the female extracts elicit species‐specific courtship behaviour and attraction in an olfactometer bioassay. Attractiveness of the sex pheromone extracts seems to differ in the investigated species, being highly attractive for males in B. difformis and only moderately attractive in B. tilicola. Female B. difformis are attractive from late pupal stages until death of the imago. In contrast, female B. optata and B. tilicola are not attractive to males before emergence from the pupa and attractiveness decreases in older females. The pheromones seem to be located on the surface of several body compartments of freshly emerged females. Sexual pheromones of all three species represent multicomponent blends and can be separated in several fractions via thin layer chromatography (TLC). Males of all species show courtship behaviour when placed on developed TLC sheets, indicating the position of the biologically active compounds. In B. difformis and B. optata, the most non‐polar TLC fraction is attractive to males, whereas the single fractions of B. tilicola‐pheromone elicited almost no attraction of males.
Effect of generalist insect herbivores on introduced Lepidium draba (Brassicaceae): implications for the enemy release hypothesis
Authors: Puliafico K. P. , Schwarzländer M. , Harmon B. L. , Hinz H. L. 
Published: July 2008

AbstractThe enemy release hypothesis (ERH) states that decreased regulation by natural enemies allows plants to increase in distribution, abundance and vigour following their introduction into an exotic range. Invasive plants rarely escape herbivory entirely, and for hoary cress [Lepidium draba L. (Brassicaceae)] it has been demonstrated that generalist insect abundance is greater in its introduced North American range than in the native European range. We assessed the role of increased generalist herbivory on hoary cress using representatives of four important herbivore niches commonly found in the introduced range. We experimentally examined the density dependent impact of these herbivores individually and in combination on hoary cress in a series of greenhouse experiments. We found that defoliation of the oligophagous diamondback moth Plutella xylostella (L.) (Lep., Plutellidae) had the strongest and most consistent impact, while damage by the stem‐mining weevil Ceutorhynchus americanus Buchanan (Col., Curculionidae) tended to have the highest per capita effect. Plant response to feeding by the oligophagous crucifer flea beetle Phyllotreta cruciferae (Goeze) (Col., Chrysomelidae) was minor despite obvious feeding damage, and the impact of the polyphagous tarnished plant bug Lygus hesperus Knight (Het., Miridae) was negligible. In multiple‐species experiments, herbivore impacts were usually additive. In general, we found that hoary cress can tolerate high densities of oligophagous insect herbivory and effectively resisted attack by the polyphagous L. hesperus, but also the oligophagous C. americanus. Our results indicate that a combination of plant resistance and tolerance allows hoary cress to withstand increased generalist herbivore load in its introduced range, consistent with the predictions of the ERH.
Towards Ethically Improved Animal Experimentation in the Study of Animal Reproduction
Authors: Blache D , Martin GB , Maloney SK 
Published: July 2008

ContentsThe ethics of animal‐based research is a continuing area of debate, but ethical research protocols do not prevent scientific progress. In this paper, we argue that our current knowledge of the factors that affect reproductive processes provides researchers with a solid foundation upon which they can conduct more ethical research and simultaneously produce data of higher quality. We support this argument by showing how a deep understanding of the genetics, nutrition and temperament of our experimental animals can improve compliance with two of the ‘3 Rs’, reduction and refinement, simply by offering better control over the variance in our experimental model. The outcome is a better experimental design, on both ethical and scientific grounds.
Functional Differences in the Growth Hormone and Insulin‐like Growth Factor Axis in Cattle and Pigs: Implications for Post‐partum Nutrition and Reproduction
Authors: Lucy MC 
Published: July 2008

ContentsGrowth hormone (GH) and insulin‐like growth factor‐I (IGF‐I) control growth and lactation in cattle and swine. Insulin participates in the endocrinology of growth and lactation because insulin and GH are antagonistic in their actions. Dairy cows experience a period of negative energy balance during the first 4–8 weeks post‐partum. During this period, their somatotropic axis (comprised of GH, the GH receptor and IGF‐I) becomes uncoupled and there is elevated GH and diminished IGF‐I in the circulation. Blood insulin concentrations are low as well. Sows are different from dairy cows because their somatotropic axis remains coupled during lactation and both GH and IGF‐I are elevated. Nonetheless, sows that become catabolic during lactation will have reduced IGF‐I concentrations. Sows are inseminated after weaning so their metabolic state is different from post‐partum beef and dairy cows that are inseminated when they are lactating. Dairy cows are fed ad libitum and naturally have low IGF‐I during lactation. Sows have elevated IGF‐I when they are well‐fed. A threshold of IGF‐I protein in follicular fluid may be met by local ovarian (paracrine/autocrine) and endocrine sources of IGF‐I. Nutritionally induced changes in insulin and in liver IGF‐I secretion that arise from perturbations of the somatotropic axis have a direct effect on the ovary through the endocrine actions of insulin and IGF‐I. Sows and cows that are nutritionally compromised have low concentrations of insulin and IGF‐I in their blood and this theoretically reduces ovarian responsiveness to gonadotropins. Although sows are inseminated after weaning, there appear to be carry‐over effects of the previous lactation on the ovarian follicular populations that develop after the sow is weaned. Understanding the mechanisms through which metabolic hormones control ovarian function may lead to improved reproductive management of both pigs and cattle because lactation and post‐partum reproduction are closely tied in both species.
Seasonality of Reproduction in Mammals: Intimate Regulatory Mechanisms and Practical Implications
Authors: Chemineau P , Guillaume D , Migaud M , Thiéry JC , Pellicer‐Rubio MT , Malpaux B 
Published: July 2008

ContentsFarm mammals generally express seasonal variations in their production traits, thus inducing changing availability of fresh derived animal products (meat, milk and cheese) or performances (horses). This is due to a more or less marked seasonal birth distribution in sheep and goats, in horses but not cattle. Birth peak occurs at the end of winter‐early spring, the most favourable period for the progeny to survive. Most species show seasonal variations in their ovulation frequency (presence or absence of ovulation), spermatogenic activity (from moderate decrease to complete absence of sperm production), gamete quality (variations in fertilization rates and embryo survival), and also sexual behaviour. The intimate mechanism involved is a complex combination of endogenous circannual rhythm driven and synchronized by light and melatonin. Profound and long‐term neuroendocrine changes involving different neuromediator systems were described to play a role in these processes. In most species artificial photoperiodic treatments consisting of extra‐light during natural short days (in sheep and goats and mares) or melatonin during long days (in sheep and goats) are extensively used to either adjust the breeding season to animal producer needs and/or to completely overcome seasonal variations of sperm production in artificial insemination centres. Pure light treatments (without melatonin), especially when applied in open barns, could be considered as non‐invasive ones which fully respect animal welfare. Genetic selection could be one of the future ways to decrease seasonality in sheep and goats.
Mechanisms for Dominant Follicle Selection in Monovulatory Species: A Comparison of Morphological, Endocrine and Intraovarian Events in Cows, Mares and Women
Authors: Mihm M , Evans ACO 
Published: July 2008

ContentsThe selection of a single ovarian follicle for further differentiation and finally ovulation is a shared phenomenon in monovulatory species from different phylogenetic classes. The commonality of dominant follicle (DF) development leads us to hypothesize that mechanisms for DF selection are conserved. This review highlights similarities and differences in follicular wave growth between cows, mares and women, addresses the commonality of the transient rises in FSH concentrations, and discusses the follicular secretions oestradiol and inhibin with their regulatory roles for FSH. In all three species, rising FSH concentrations induce the emergence of a follicle wave and cohort attrition occurs during declining FSH concentrations, culminating in DF selection. Cohort secretions are initially responsible for declining FSH, which is subsequently suppressed by the selected DF lowering it below the threshold of FSH requirements of all other cohort follicles. The DF acquires relative FSH‐independence in order to continue growth and differentiation during low (cow, mare) or further declining FSH concentrations (women), and thus may be the one cohort follicle with the lowest FSH requirement due to enhanced FSH signalling. In all three monovulatory species a transition from FSH‐ to LH‐dependence is postulated as the mechanism for the continued development of the selected DF. In addition, FSH and IGF enhance each other’s ability to stimulate follicle cell function and access of IGF‐I and ‐II to the type 1 receptor is regulated by IGF binding proteins that are in turn regulated by specific proteases; all of which have been ascribed a role in DF development. No fundamental differences in DF selection mechanisms have been identified between the different species studied. Thus functional studies of the selection of DFs in cattle and mares are also valuable for identifying genes and pathways regulating DF development in women.
Regulation of Luteal Function and Corpus Luteum Regression in Cows: Hormonal Control, Immune Mechanisms and Intercellular Communication
Authors: Skarzynski DJ , Ferreira‐Dias G , Okuda K 
Published: July 2008

ContentsThe main function of the corpus luteum (CL) is production of progesterone (P4). Adequate luteal function to secrete P4 is crucial for determining the physiological duration of the oestrous cycle and for achieving a successful pregnancy. The bovine CL grows very fast and regresses within a few days at luteolysis. Mechanisms controlling development and secretory function of the bovine CL may involve many factors that are produced both within and outside the CL. Some of these regulators seem to be prostaglandins (PGs), oxytocin, growth and adrenergic factors. Moreover, there is evidence that P4 acts within the CL as an autocrine or paracrine regulator. Each of these factors may act on the CL independently or may modify the actions of others. Although uterine PGF2α is known to be a principal luteolytic factor, its direct action on the CL is mediated by local factors: cytokines, endothelin‐1, nitric oxide. The changes in ovarian blood flow have also been suggested to have some role in regulation of CL development, maintenance and regression.
Captive Breeding of Cheetahs in South Africa – 30 Years of Data from the de Wildt Cheetah and Wildlife Centre
Authors: Bertschinger HJ , Meltzer DGA , Van Dyk A 
Published: July 2008

ContentsThe de Wildt Cheetah and Wildlife Centre was established in 1971 and the first cheetah cubs were born in 1975. During the period 1975–2005, 242 litters were born with a total of 785 cubs. Mean cub survival from 1 to 12 months and greater than 12 months of age was 71.3 and 66.2%, respectively. The majority of losses (84.9%) occurred during the first month postpartum whereas only 15.1% deaths took place between 1 and 12 months of age. Females were first bred at an age of approximately 3 years, reached maximum reproductive age at 6–8 years, where after fertility declined. Males reached peak reproduction at 6 and maintained this for up to 12 years of age. Male fertility was best correlated with sperm morphology. During recent years, for practical purposes, males were allocated to ‘good’ (≥70% normal), ‘fair’ (40–70% normal) and ‘poor’ (<40% normal) categories according to sperm morphology count. The breeding males were selected from the good (preferably) and fair categories but poor category males were also used at times. Average litter sizes for ‘good’, ‘fair’ and ‘poor’ males were 3.44 (n = 21), 3.14 (n = 18) and 2.28 (n = 18), respectively. In females the heritability for litter size was high at 0.5848 (532 progeny, 1975–2007) and the maternal heritability for cub mortality was estimated to be 0.596. The data from the de Wildt Cheetah and Wildlife Centre and two other centres in the world (Kapama and Wassenaar) demonstrate that cheetah can be bred successfully in captivity.
Non‐invasive Monitoring of Hormones: A Tool to Improve Reproduction in Captive Breeding of the Eurasian Lynx
Authors: Dehnhard M , Naidenko S , Frank A , Braun B , Göritz F , Jewgenow K 
Published: July 2008

ContentsThe survival of many critical endangered mammal species is often depending on successful captive breeding programmes which include the future option of reintroduction to the wild. Breeding in captivity also demands the application of modern assisted reproductive techniques to ensure maximal biodiversity, but knowledge on reproductive physiology is often limited. Therefore, non‐invasive monitoring of urinary and faecal hormones has become an important tool for reproductive management. To exemplify the importance of non‐invasive hormone monitoring, we choose the Eurasian lynx as a model for the world’s most endangered felid species, the Iberian lynx. We analysed faecal samples of pregnant and pseudo‐pregnant female Eurasian lynxes during a 3‐year study period. Compared to pre‐mating levels faecal progesterone metabolite profiles revealed a tendency towards higher levels in pregnant and pseudo‐pregnant females with no difference between both categories. Oestrogen levels raised in both pregnant and pseudo‐pregnant females with a tendency to be more elevated and prolonged in pregnant females. Surprisingly both E2 and P4 metabolites were highly correlated (r2 =0.8131, p < 0.0001) showing a postpartum increase both in pregnant and pseudo‐pregnant females. The results from the Eurasian lynx revealed that the measurement of faecal progesterone metabolites led to profiles dissimilar to profiles shown in other felid species, but similar to those from faecal gestagen metabolite analysis in the Iberian lynx. To identify faecal gestagen and oestrogen metabolites a radio‐metabolism study was performed. Using the progesterone immunoassay two major progesterone metabolites were detected demonstrating that the assay indeed tracks the relevant metabolites. The oestrogen assay measured authentic 17β‐oestradiol and oestrone, and their conjugates. The analysis of the faecal metabolite composition in samples from early and late pregnancy and lactation particularly revealed a distinct shift in the relation between 17β‐oestradiol and oestrone that changed in favour of oestrone. This might indicate different hormone sources during and after pregnancy (corpus luteum, placenta). We hypothesize, that placental steroid analysis in combination with other highly sophisticated analytical techniques, like liquid chromatography mass spectrometry or urinary relaxin analysis may led to analytical options to confirm pregnancy and to differentiate this from pseudo‐pregnancy in lynx species.
Improved Detection of Reproductive Status in Dairy Cows Using Milk Progesterone Measurements
Authors: Friggens NC , Bjerring M , Ridder C , Højsgaard S , Larsen T 
Published: July 2008

ContentsThis study tested a model for predicting reproductive status from in‐line milk progesterone `measurements. The model is that of Friggens and Chagunda [Theriogenology 64 (2005) 155]. Milk progesterone measurements (n = 55 036) representing 578 lactations from 380 cows were used to test the model. Two types of known oestrus were identified: (1) confirmed oestrus (at which insemination resulted in a confirmed pregnancy, n = 121) and (2) ratified oestrus (where the shape of the progesterone profile matched that of the average progesterone profile of a confirmed oestrus, n = 679). The model detected 99.2% of the confirmed oestruses. This included a number of cases (n = 16) where the smoothed progesterone did not decrease below 4 ng/ml. These cows had significantly greater concentrations of progesterone, both minimum and average, suggesting that between cow variation exists in the absolute level of the progesterone profile. Using ratified oestruses, model sensitivity was 93.3% and specificity was 93.7% for detection of oestrus. Examination of false positives showed that they were largely associated with low concentrations of progesterone, fluctuating around the 4 ng/ml threshold. The distribution of time from insemination until the model detected pregnancy failure had a median of 22 days post‐insemination. In this test, the model was run using limited inputs, the potential benefits of including additional non‐progesterone information were not evaluated. Despite this, the model performed at least as well as other oestrus detection systems.