Collection and freezing of equine epididymal spermatozoa

The epididymis and vas deferens store an important number of fertile spermatozoa called the extragonadal sperm reserves. These stored spermatozoa can be collected in an ultimate attempt to preserve viable spermatozoa of a critically ill or dying stallion. Epididymides are collected via routine castration. After cooled transport of the testicles and epididymides, spermatozoa are collected either by retrograde flushing or by the float-up method. Retrograde flushing usually results in a much higher sperm yield and is considered the method of choice. Epididymal spermatozoa can be frozen using standard freezing protocols

Male sperm whale acoustic behavior observed from multipaths at a single hydrophone

Sperm whales generate transient sounds (clicks) when foraging. These clicks have been described as echolocation sounds, a result of having measured the source level and the directionality of these signals and having extrapolated results from biosonar tests made on some small odontocetes. The authors propose a passive acoustic technique requiring only one hydrophone to investigate the acoustic behavior of free-ranging sperm whales. They estimate whale pitch angles from the multipath distribution of click energy. They emphasize the close bond between the sperm whale’s physical and acoustic activity, leading to the hypothesis that sperm whales might, like some small odontocetes, control click level and rhythm. An echolocation model estimating the range of the sperm whale’s targets from the interclick interval is computed and tested during different stages of the whale’s dive. Such a hypothesis on the echolocation process would indicate that sperm whales echolocate their prey layer when initiating their dives and follow a methodic technique when foraging

Thrifty swimming with shear-thinning

Microscale propulsion is integral to numerous biomedical systems, for example biofilm formation and human reproduction, where the surrounding fluids comprise suspensions of polymers. These polymers endow the fluid with non-Newtonian rheological properties, such as shear-thinning and viscoelasticity. Thus, the complex dynamics of non-Newtonian fluids presents numerous modelling challenges, strongly motivating experimental study. Here, we demonstrate that failing to account for "out-of-plane" effects when analysing experimental data of undulatory swimming through a shear-thinning fluid results in a significant overestimate of fluid viscosity around the model swimmer C. elegans. This miscalculation of viscosity corresponds with an overestimate of the power the swimmer expends, a key biophysical quantity important for understanding the internal mechanics of the swimmer. As experimental flow tracking techniques improve, accurate experimental estimates of power consumption using this technique will arise in similar undulatory systems, such as the planar beating of human sperm through cervical mucus, will be required to probe the interaction between internal power generation, fluid rheology, and the resulting waveform

Comparison of five different methods to assess the concentration of boar semen

Both for research and practical purposes, accurate and repeatable methods are required to assess the concentration of boar semen samples. Since the method which is used may influence the results considerably, the aim of the present study was to compare 5 frequently used techniques to determine boar semen concentration. Fifty ejaculates were collected from 37 different boars at an artificial insemination centre. Subsequently, each ejaculate was analyzed for sperm concentration by means of 2 different types of colorimeters (Colorimeter 1: Model 252, Sherwood Scientific Ltd, Cambridge, UK; Colorimeter 2: Ciba-Corning, Schippers, Bladel, The Netherlands), the Burker counting chamber (golden standard), and the Hamilton Thorne Analyzer (Ceros 42.1) using 2 types of Leja chambers (the 'former' and the 'recently developed'). Each ejaculate was assessed 5 times with each of the 5 methods, and the repeatability, expressed by coefficient of variation (CV), was determined for each method. The different methods were compared using Pearson's correlations and limits of agreement. The colorimeters yielded the lowest CV's (both 3.7%), while the former Leja chamber resulted in the highest CV (12.4%). Moreover, significant (P0.71) were found between the results obtained by the different methods. The limits of agreement plots showed that none of the methods consistently over- or underestimated the sperm concentrations when compared to the Burker chamber, although there was a tendency toward higher over- or underestimation in highly concentrated sperm samples. Based on our results, there were no major differences in the assessment of sperm concentration between the evaluated methods. The choice of method used in a laboratory could therefore be based on factors such as cost, number of samples to be assessed and practical use, without thereby negatively affecting the validity of the results thus obtained

Structure and optics of the anterior segment of the cetacean eye : a thesis presented in fulfilment of the requirements for the degree of Master of Philosophy at Massey University

The anterior segment of the mammalian eye is concerned with the function and maintenance of its optical components, the most important of these being the maintenance of transparency and stable intraocular pressure. The structures of the eye change throughout life. Continuous growth occurs in the lens, and a number of other changes associated with aging also occur, many of which reduce visual capacity. Many of these manifest in humans because of their long life span but have very little relevance in terms of survival. However, other long lived animals such as some birds, reptiles and whales, could be severely compromised by complete or partial blindness associated with aging. The aims of this study were to evaluate the importance of vision as a sense in whales by observation of the structure and optics of the anterior segment, and compare the findings with other species whose visual functions are well known. Pathological changes were recorded where appropriate. The findings in this thesis are based on a three year survey of eyes from 45 whales in which i) differences between species in the size of the globe, lens, and cornea are described ii) the unique histological structure of the uveal tract is demonstrated and defined iii) evidence of emmetropia in both air and water from NMR images of two eyes is given iv) lens shape and capsular features which indicate that there could be a capacity for accommodation, are described, and v) lens pathology (four cataracts and one case of phacolysis) is described in five animals. The largest whales (baleen and sperm) had the largest eyes, but this was mainly due to the thickness of sclera. Internal dimensions showed little variation with respect to body size, suggesting that there is an upper limit on internal size which is dependant on the focal length of the lens, a structure which enlarges only slightly with age. Corneal and lens sizes were especially large in the baleen whales, and particularly small in the sperm whale. The uveal tract was found to be very vascular when compared to other species, and particularly well innervated with specialised nerve endings which are thought to be unique to cetaceans. Although the findings are not conclusive, evidence from this study suggests that the whales' unique uveal vasculature and aqueous drainage methods may be instrumental in modifying the dioptric strength of the eye. The abundance of specialised pressure-receptors in the ciliary body indirectly supports a proposed mechanism for this, whereby the engorged ciliary body raises intraocular pressure causing increased corneal curvature, and releases tension on the zonule to allow 'rounding up' of the lens. Optically, the study showed that eyes from two long-finned pilot whales were emmetropic by virtue of a cornea with only a very small amount of optical power in both air and water, and a very powerful lens (about 72D in water). Emmetropia was thus not affected unduly by transition from air to water as it is in most mammals, where the cornea is optically very significant in air but neutral in water. Lenses in both animals showed an unusual 'bump' on the central posterior : surface, and the increased radius of curvature in this area was responsible for the very high dioptric strength of the lenses. The prevalence of lens pathology, particularly cataracts in young animals, was high. but in all cases the cause was unknown

The Spermatophore in Glossina morsitans morsitans: Insights into Male Contributions to Reproduction.

Male Seminal Fluid Proteins (SFPs) transferred during copulation modulate female reproductive physiology and behavior, impacting sperm storage/use, ovulation, oviposition, and remating receptivity. These capabilities make them ideal targets for developing novel methods of insect disease vector control. Little is known about the nature of SFPs in the viviparous tsetse flies (Diptera: Glossinidae), vectors of Human and Animal African trypanosomiasis. In tsetse, male ejaculate is assembled into a capsule-like spermatophore structure visible post-copulation in the female uterus. We applied high-throughput approaches to uncover the composition of the spermatophore in Glossina morsitans morsitans. We found that both male accessory glands and testes contribute to its formation. The male accessory glands produce a small number of abundant novel proteins with yet unknown functions, in addition to enzyme inhibitors and peptidase regulators. The testes contribute sperm in addition to a diverse array of less abundant proteins associated with binding, oxidoreductase/transferase activities, cytoskeletal and lipid/carbohydrate transporter functions. Proteins encoded by female-biased genes are also found in the spermatophore. About half of the proteins display sequence conservation relative to other Diptera, and low similarity to SFPs from other studied species, possibly reflecting both their fast evolutionary pace and the divergent nature of tsetse's viviparous biology

Telomere lengths in human oocytes, cleavage stage embryos and blastocysts

Telomeres are repeated sequences that protect the ends of chromosomes and harbour DNA-repair proteins. Telomeres shorten during each cell division in the absence of telomerase. When telomere length becomes critically short, cell senescence occurs. Telomere length therefore reflects both cellular ageing and capacity for division. We have measured telomere length in human germinal vesicle (GV) oocytes and pre-implantation embryos, by quantitative fluorescence in-situ hybridisation (Q-FISH), providing baseline data towards our hypothesis that telomere length is a marker of embryo quality. The numbers of fluorescent foci suggest that extensive clustering of telomeres occurs in mature GV stage oocytes, and in pre-implantation embryos. When calculating average telomere length by assuming that each signal presents one telomere, the calculated telomere length decreased from the oocyte to the cleavage stages, and increased between the cleavage stages and the blastocyst (11.12 vs 8.43 vs 12.22kb respectively, p<0.001). Other methods of calculation, based upon expected maximum and minimum numbers of telomeres, confirm that telomere length in blastocysts is significantly longer than cleavage stages. Individual blastomeres within an embryo showed substantial variation in calculated average telomere length. This study implies that telomere length changes according to the stage of pre-implantation embryo development