Preliminary investigations into the ethological relevance of round-pen (round-yard) training of horses

Recently, training horses within round-pens has increased in popularity. Practitioners often maintain that the responses they elicit from horses are similar to signals used with senior conspecifics. To audit the responses of horses to conspecifics, 6 mare-young-horse dyads, this study introduced them to each other in a round-pen and videoed them for 8 min. These dyads spent significantly more time farther than 10 m apart than they did less than 1 m apart (p < .001). The time they spent less than 1 m apart decreased over the 8-min test period (p = .018). Mares occupied the center of the round-pen and chased youngsters for 0.73% of the test period (p < .001). Mares made all agonistic approaches (p < .001), and youngsters (p = .018) made all investigative approaches. Head lowering and licking-and-chewing were exhibited most when the youngsters were facing away from the mares (p < .001). The frequency of head lowering increased during the test period (p = .027), whereas the frequency of licking-and-chewing did not change. The results bring into question the popular interpretation and ethological relevance of equine responses commonly described in round-pen training and show that mares did not condition young horses to remain in close proximity to them.     

The effect of medroxyprogesterone acetate on behavioural responses of captive female hamadryas baboons (Papio hamadryas)

Female hormonal contraception is considered here as an alternative to vasectomy for population control in social groups of captive hamadryas baboons (Papio hamadryas). While female hormonal contraceptive methods have been successful, behavioural effects of such agents represent a potential welfare concern. This study examined the effect of medroxyprogesterone acetate (MPA; 3.5 mg/kg) on perineal tumescence and behaviour in three social groups (total of 3 males, 22 females) of captive hamadryas baboons. The agent had little effect on social interactions such as grooming relationships, aggression and affiliation (all P > 0.05), but did cause a reduction in sexual behaviour (P < 0.001). Females-mounting-females and females receiving mounting was decreased during MPA treatment compared with the minimal tumescence phase (P < 0.001). Age strongly influenced the contraceptive's duration: there was a significant correlation between age and latency of return to oestrus post-MPA (r = 0.832, P < 0.001) with the latency increasing by 2.61 days per year of age on average. Age also influenced the frequency of behaviours such as affiliation and aggression (P < 0.001 and P = 0.044, respectively). The absence of adverse behavioural effects further supports the use of MPA in the hamadryas baboon, and its potential use in other non-human primates.     

An investigation of racing performance and whip use by jockeys in thoroughbred races

Concerns have been expressed concerning animal-welfare issues associated with whip use during Thoroughbred races. However, there have been no studies of relationships between performance and use of whips in Thoroughbred racing. Our aim was to describe whip use and the horses' performance during races, and to investigate associations between whip use and racing performance. Under the Australian Racing Board (ARB) rules, only horses that are in contention can be whipped, so we expected that whippings would be associated with superior performance, and those superior performances would be explained by an effect of whipping on horse velocities in the final 400 m of the race. We were also interested to determine whether performance in the latter sections of a race was associated with performance in the earlier sections of a race. Measurements of whip strikes and sectional times during each of the final three 200 metre (m) sections of five races were analysed. Jockeys in more advanced placings at the final 400 and 200 m positions in the races whipped their horses more frequently. Horses, on average, achieved highest speeds in the 600 to 400 m section when there was no whip use, and the increased whip use was most frequent in the final two 200 m sections when horses were fatigued. This increased whip use was not associated with significant variation in velocity as a predictor of superior placing at the finish.     

Actin-based centripetal flow: phosphatase inhibition by calyculin-A alters flow pattern, actin organization, and actomyosin distribution

Previous studies have suggested that the actin-based centripetal flow process in sea urchin coelomocytes is the result of a two-part mechanism, actin polymerization at the cell edge coupled with actomyosin contraction at the cell center. In the present study, we have extended the testing of this two-part model by attempting to stimulate actomyosin contraction via treatment of coelomocytes with the phosphatase inhibitor Calyculin A (CalyA). The effects of this drug were studied using digitally-enhanced video microscopy of living cells combined with immunofluorescent localization and scanning electron microscopy. Under the influence of CalyA, the coelomocyte actin cytoskeleton undergoes a radical reorganization from a dense network to one displaying an array of tangential arcs and radial rivulets in which actin and the Arp2/3 complex concentrate. In addition, the structure and dynamics of the cell center are transformed due to the accumulation of actin and membrane in this region and the constriction of the central actomyosin ring. Physiological evidence of an increase in actomyosin-based contractility following CalyA treatment was demonstrated in experiments in which cells generated tears in their cell centers in response to the drug. Western blotting and immunofluorescent localization with antibodies against the phosphorylated form of the myosin regulatory light chain (MRLC) suggested that the demonstrated constriction of actomyosin distribution was the result of CalyA-induced phosphorylation of MRLC. Overall, the results suggest that there is significant cross talk between the two underlying mechanisms of actin polymerization and actomyosin contraction, and indicate that changes in actomyosin tension may be translated into alterations in the structural organization of the actin cytoskeleton.     

Giant cells fromSaccharomyces uvarum grown after X-irradiation

Yeast cells, Saccharomyces uvarum, were irradiated with X-rays and grown in liquid suspension. Glucose as the only carbon source was limited to 12.5 mM. Under these conditions giant cells are formed. Cell number, glucose utilization, ethanol production and oxygen consumption are measured during the time of growth. The mean weight of single cells in the stationary phase increases up to 75 krad and is not due to an uptake of water. In irradiated cultures oxygen consumption and glucose utilization per cell are higher than in control cells. The data demonstrate that synthesis- and energy-metabolism during the formation of non-dividing, radiation-induced giant cells is increased.     

Morphogenesis and fate of the residual body in human spermiogenesis

Summary In the human testis the formation of the residual body of the spermatid and its morphological changes during and after spermiation were studied by means of electron microscopy. The caudal cytoplasmic mass of the late spermatid contains a Golgi complex, mitochondria, annulate lamellae, a chromatoid body, flower-like structures, ribosomes, a few large vacuoles, myelin-like membrane profiles and sporadic lipid droplets. When, by detachment of the caudal cytoplasm from the free spermatozoon, the residual body is formed, the chromatoid body has disappeared; the mitochondria are clustered peripherally; the ribosomes appear as a single complex in contact with a large vacuole containing granular material; in place of the Golgi complex aggregations of vesicles are present. The lipid droplets remain unchanged. The residual bodies or their fragments are either extruded via the seminiferous tubular lumen into the excurrent ducts or they are engulfed by Sertoli cells where in the supranuclear region the successive steps of decomposition can be observed. The participation of the various constituents in the disintegration of the residual body is discussed. In contrast to other mammalian species, in man the sporadic lipid droplets seem to be of minor importance in the fate of the residual body.     

Automatic morphometric analysis of retrograde changes in the nucleus n. facialis at different ontogenetic stages in the rat

Summary The grey level index (= GLI) and the fresh volume were determined with the image analyser Micro-Videomat for the nucl. n. facialis after axotomy of the left n. facialis. The experiments were performed on 10 rats in different stages of ontogenesis. The GLI is a quantitative parameter which could be quickly obtained and which demonstrated quantitative changes during retrograde reaction in the respective centres. A decrease in the fresh volumes of the affected nucl. n. facialis could also be demonstrated. The meaning of GLI is discussed.Supported by Deutsche Forschungsgemeinschaft grants Kr 289/10 and Zi 192/1Dedicated to Prof. Dr. H. Leonhardt on the occasion of his 60th birthday     

FISH in der Diagnostik hämatologischer Neoplasien

All hematological malignancies are characterized by considerable clinical heterogeneity. The diverse entities can be subdivided into a variety of prognosis-defining subtypes on the basis of cytogenetic aberrations and molecular mutations. To adapt the intensity of treatment to the patient’s individual risk profile, an exact classification of the subtypes on the basis of genetic markers is essential. Diverse fluorescent in situ hybridization (FISH) techniques thereby play a central role in interaction with classic chromosome banding analyses for clarifying findings of chromosome analyses, such as in the acute leukemias, or for classifying the diverse subtypes, as in the non-Hodgkin’s lymphomas. Depending on the disease, the clinical impact of FISH varies. It is used as the method of choice for genetic characterization (e.g., in multiple myeloma) or is used in combination with chromosome banding analysis. Furthermore, interphase FISH is essential when rapid confirmation of the diagnosis is needed, as in acute promyelocytic leukemia with the t(15;17)/PML-RARA rearrangement, for which therapy with all-trans retinoic acid (ATRA) should be immediately started.     

An Analysis of Overstory Tree Canopy Cover in Sites Occupied by Native and Introduced Cottontails in the Northeastern United States with Recommendations for Habitat Management for New England Cottontail

The New England cottontail (Sylvilagus transitionalis) is a high conservation priority in the Northeastern United States and has been listed as a candidate species under the Endangered Species Act. Loss of early successional habitat is the most common explanation for the decline of the species, which is considered to require habitat with dense low vegetation and limited overstory tree canopy. Federal and state wildlife agencies actively encourage landowners to create this habitat type by clearcutting blocks of forest. However, there are recent indications that the species also occupies sites with moderate overstory tree canopy cover. This is important because many landowners have negative views about clearcutting and are more willing to adopt silvicultural approaches that retain some overstory trees. Furthermore, it is possible that clearcuts with no overstory canopy cover may attract the eastern cottontail (S. floridanus), an introduced species with an expanding range. The objective of our study was to provide guidance for future efforts to create habitat that would be more favorable for New England cottontail than eastern cottontail in areas where the two species are sympatric. We analyzed canopy cover at 336 cottontail locations in five states using maximum entropy modelling and other statistical methods. We found that New England cottontail occupied sites with a mean overstory tree canopy cover of 58% (SE±1.36), and was less likely than eastern cottontail to occupy sites with lower overstory canopy cover and more likely to occupy sites with higher overstory canopy cover. Our findings suggest that silvicultural approaches that retain some overstory canopy cover may be appropriate for creating habitat for New England cottontail. We believe that our results will help inform critical management decisions for the conservation of New England cottontail, and that our methodology can be applied to analyses of habitat use of other critical wildlife species.