Liberation of host heme by Clostridioides difficile-mediated damage enhances Enterococcus faecalis fitness during infection

IMPORTANCE

Clostridioides difficile and Enterococcus faecalis are two pathogens of great public health importance. Both bacteria colonize the human gastrointestinal tract where they are known to interact in ways that worsen disease outcomes. We show that the damage associated with C. difficile infection (CDI) releases nutrients that benefit E. faecalis. One particular nutrient, heme, allows E. faecalis to use oxygen to generate energy and grow better in the gut. Understanding the mechanisms of these interspecies interactions could inform therapeutic strategies for CDI.

Evolutionary Patterns of Modularity in the Linkage Systems of the Skull in Wrasses and Parrotfish

The concept of modularity is fundamental to understanding the evolvability of morphological structures and is considered a central framework for the exploration of functionally and developmentally related subsets of anatomical traits. In this study, we explored evolutionary patterns of modularity and integration in the 4-bar linkage biomechanical system of the skull in the fish family Labridae (wrasses and parrotfish). We measured evolutionary modularity and rates of shape diversification of the skull partitions of three biomechanical 4-bar linkage systems using 205 species of wrasses (family: Labridae) and a three-dimensional geometric morphometrics data set of 200 coordinates. We found support for a two-module hypothesis on the family level that identifies the bones associated with the three linkages as being a module independent from a module formed by the remainder of the skull (neurocranium, nasals, premaxilla, and pharyngeal jaws). We tested the patterns of skull modularity for four tribes in wrasses: hypsigenyines, julidines, cheilines, and scarines. The hypsigenyine and julidine groups showed the same two-module hypothesis for Labridae, whereas cheilines supported a four-module hypothesis with the three linkages as independent modules relative to the remainder of the skull. Scarines showed increased modularization of skull elements, where each bone is its own module. Diversification rates of modules show that linkage modules have evolved at a faster net rate of shape change than the remainder of the skull, with cheilines and scarines exhibiting the highest rate of evolutionary shape change. We developed a metric of linkage planarity and found the oral jaw linkage system to exhibit high planarity, while the rest position of the hyoid linkage system exhibited increased three dimensionality. This study shows a strong link between phenotypic evolution and biomechanical systems, with modularity influencing rates of shape change in the evolution of the wrasse skull.

Carbonic Anhydrase Inhibition as a Target for Antibiotic Synergy in Enterococci

Enterococcus faecalis is a hospital-associated opportunistic pathogen that can cause infections with high mortality, such as infective endocarditis. With an increasing occurrence of multidrug-resistant enterococci, there is a need for alternative strategies to treat enterococcal infections. We isolated a gentamicin-hypersusceptible E. faecalis strain from a patient with infective endocarditis that carried a mutation in the alpha-carbonic anhydrase (α-CA) and investigated how disruption of α-CA sensitized E. faecalis to killing with gentamicin. The gentamicin-hypersusceptible α-CA mutant strain showed increased intracellular gentamicin uptake in comparison to an isogenic strain encoding full-length, wild-type α-CA. We hypothesized that increased gentamicin uptake could be due to increased proton motive force (PMF), increased membrane permeability, or both. We observed increased intracellular ATP production in the α-CA mutant strain, suggesting increased PMF-driven gentamicin uptake contributed to the strain's gentamicin susceptibility. We also analyzed the membrane permeability and fatty acid composition of isogenic wild-type and α-CA mutant strains and found that the mutant displayed a membrane composition that was consistent with increased membrane permeability. Finally, we observed that exposure to the FDA-approved α-CA inhibitor acetazolamide lowered the gentamicin MIC of eight genetically diverse E. faecalis strains with intact α-CA but did not change the MIC of the α-CA mutant strain. These results suggest that α-CA mutation or inhibition increases PMF and alters membrane permeability, leading to increased uptake of gentamicin into E. faecalis. This connection could be exploited clinically to provide new combination therapies for patients with enterococcal infections. IMPORTANCE Enterococcal infections can be difficult to treat, and new therapeutic approaches are needed. In studying an E. faecalis clinical strain from an infected patient, we found that the bacteria were rendered hypersusceptible to aminoglycoside antibiotics through a mutation that disrupted the α-CA. Our follow-on work suggested two different ways that α-CA disruption causes increased gentamicin accumulation in E. faecalis: increased proton motive force-powered uptake and increased membrane permeability. We also found that a mammalian CA inhibitor could sensitize a variety of E. faecalis strains to killing with gentamicin. Given that mammalian CA inhibitors are frequently used to treat conditions such as glaucoma, hypertension, and epilepsy, our findings suggest that these "off-the-shelf" inhibitors could also be useful partner antibiotics for the treatment of E. faecalis infections.

Decreasing Extra Tube Collections in a Healthcare System

Introduction/Objective

To determine a mechanism for obtaining and utilizing data on extra specimens collected that were not used, monitoring collections and decreasing the need to collect these specimens in order to save the patient’s blood from being wasted, as well as the resources used to collect and house the extra specimens.

Methods

Internal database, Sunquest, and Tableau

Results

Starting in early 2017, statistics were pulled and analyzed by our Phlebotomy Best Practice committee in order to obatin a solid basis to review all extra specimens being collected (excluding blue, lavender, and lithium herparin tubes) by phlebotomy in order to save teh patient’s blood from being disposed of without being used for testing, continue to look for ways to maintain blood conservation and collections, cost effectiveness due to not having to use the supplies, as well as store the specimens that were not being used for testing.

Conclusion

As of January 2020, there has been a 30% decrease in collections (yearly - over 3 years), and a maximum 45% decrease in cost (thus far) of supplies and waste. It has been a larage patient and upper management satisfier; patient’s don’t question the number of tubes being taken, and the decrease in spending makes the VP happy!

Ecomorphology of Neotropical Electric Fishes: An Integrative Approach to Testing the Relationships between Form, Function, and Trophic Ecology

The relationship between form and function is thought to play an integral role in structuring broad-scale patterns of morphological evolution and resource utilization. In ecomorphological studies, mechanical performance is widely understood to constrain the evolution of form and function. However, the relationship between form, function, and resource utilization is less clear. Additionally, seasonal fluctuations in resource availability may further complicate patterns of resource use. How organisms cope with these complexities, and the effect of these factors on broadscale patterns of morphological evolution is also poorly understood. Here we use three-dimensional geometric morphometrics, biomechanics, stable isotope analysis, and gut-content analysis to study trophic evolution in a clade of riverine-adapted electric fishes from a region with high seasonal variability; the Amazon River. We find significant and phylogenetically structured relationships among measures of trophic ecology and skull shape. We also recover a significant relationship between the mechanical advantage of the mandible and trophic position, where species feeding at higher trophic levels have narrower jaws with lower mechanical advantages, and species feeding at lower trophic levels have deeper jaws with higher mechanical advantages. Our results indicate that selection is driving the evolution of mandible shape and performance toward specialization on different trophic ecologies.

Preventing skeletal and neurological problems in guide dogs for the blind and other working dogs

Skeletal and neurological problems consistently rank among the top health conditions necessitating the withdrawal or retirement of guide dogs and other working dogs from their service roles. Management practices such as weight management and physical conditioning may help to reduce the incidence of such conditions. However, where there is at least partial genetic aetiology, selective breeding strategies are the only way to produce a lasting reduction in their incidence in future generations. The management of single gene disorders is relatively simple through the judicious use of DNA test results. Breeding strategies to tackle complex diseases, into which category many skeletal and neurological diseases fall, are more challenging but can be successful through the use of data collected through screening schemes and, most efficiently, through the use of estimated breeding values.

Longevity and mortality in Kennel Club registered dog breeds in the UK in 2014

Background

The domestic dog is one of the most diverse mammalian species, exhibiting wide variations in morphology, behaviour and morbidity across breeds. Therefore, it is not unexpected that breeds should also exhibit variation in mortality and longevity. While shorter longevity per se may not necessarily be a welfare issue, a generally foreshortened lifespan in a breed that is accompanied by a high prevalence of a particular cause of death may reveal potentially serious welfare concerns and highlight scope to improve breed welfare. Survey data gathered directly from owners offer useful insights into canine longevity and mortality that can support the overall evidence base for welfare reforms within breeds.

Results

Mortality data on 5663 deceased dogs registered with the UK Kennel Club were collected from an owner-based survey. The most commonly reported causes of death were old age (13.8%), unspecified cancer (8.7%) and heart failure (4.9%); with 5.1% of deaths reported as unknown cause. Overall median age at death was 10.33 years (interquartile range: 7.17–12.83 years). Breeds varied widely in median longevity overall from the West Highland Terrier (12.71 years) to the Dobermann Pinscher (7.67 years). There was also wide variation in the prevalence of some common causes of death among breeds, and in median longevity across the causes of death.

Conclusion

Substantial variation in the median lifespan and the prominent causes of death exists across breeds. This study has identified some breeds with both a low median lifespan and also a high proportional mortality for one or more specific causes of death that should be considered as both potential welfare concerns as well as opportunities for improvement.

Electronic supplementary material

The online version of this article (10.1186/s40575-018-0066-8) contains supplementary material, which is available to authorized users.

In vitro sperm quality and DNA integrity of SexedULTRA™ sex-sorted sperm compared to non-sorted bovine sperm

SexedULTRA^™ is an improved method of sex-sorting sperm creating a less damaging environment to retain sperm integrity through the sorting process. The aim of this study was to evaluate the in vitro characteristics of fresh and frozen bovine sperm using the SexedULTRA^™ method, and compare it to conventional (non-sorted) sperm. For both methods, percent total sperm motility was estimated visually and also classified into total and progressively motile using a computer assisted sperm analyzer (CASA). Percent sperm with intact plasma membranes (VIA) and acrosomes (PIA) were assessed using flow cytometry and sperm DNA fragmentation index (DFI) was estimated using the Bull sperm Halomax^® Kit. Two contemporaneous ejaculates from 10 bulls were processed and cryopreserved using one of the two procedures (SexedULTRA^™ and conventional). Sperm motility, VIA and PIA were assessed post-thaw (0 h) and post-incubation (3 h at 37 °C, 8 h and 24 h at 18 °C). DFI was analyzed post-thaw (0 h) and after 6, 24, 48 and 72 h of incubation at 37 °C. In a second experiment, ejaculates from 7 bulls were split sampled into the two types of processing (SexedULTRA^™ and conventional) and diluted using a fresh semen extender developed for sex-sorted bovine sperm. Sperm quality was assessed after dilution (0 h) and after incubation for 12, 24, 48, 72 h at 18°, and the same time points of incubation at 37 °C for DFI. Frozen-thawed SexedULTRA^™ sperm was significantly (P < 0.05) better than conventional semen after a 3 h incubation at 37 °C for PIA, and after a 24 h incubation at 18 °C for percent visual motility and PIA. DFI was significantly lower for SexedULTRA^™ compared to conventional at all time points of incubation (37 °C). Fresh SexedULTRA^™ sperm showed improved quality compared to conventional at all time points of incubation at 18 °C for percent visual and total motile sperm, VIA, PIA, and DFI. Significant differences were also found in progressive motile sperm immediately after dilution (0 h), but not at any time point after incubation. The results show that the SexedULTRA^™ process maintains the quality of sex-sorted sperm and, in many cases, has better in vitro longevity than conventional semen.

Large-scale survey to estimate the prevalence of disorders for 192 Kennel Club registered breeds

Background

Pedigree or purebred dogs are often stated to have high prevalence of disorders which are commonly assumed to be a consequence of inbreeding and selection for exaggerated features. However, few studies empirically report and rank the prevalence of disorders across breeds although such data are of critical importance in the prioritisation of multiple health concerns, and to provide a baseline against which to explore changes over time. This paper reports an owner survey that gathered disorder information on Kennel Club registered pedigree dogs, regardless of whether these disorders received veterinary care. This study aimed to determine the prevalence of disorders among pedigree dogs overall and, where possible, determine any variation among breeds.

Results

This study included morbidity data on 43,005 live dogs registered with the Kennel Club. Just under two thirds of live dogs had no reported diseases/conditions. The most prevalent diseases/conditions overall were lipoma (4.3%; 95% confidence interval 4.13-4.52%), skin (cutaneous) cyst (3.1%; 2.94-3.27%) and hypersensitivity (allergic) skin disorder (2.7%; 2.52-2.82%). For the most common disorders in the most represented breeds, 90 significant differences between the within breed prevalence and the overall prevalence are reported.

Conclusion

The results from this study have added vital epidemiological data on disorders in UK dogs. It is anticipated that these results will contribute to the forthcoming Breed Health & Conservation Plans, a Kennel Club initiative aiming to assist in the identification and prioritisation of breeding selection objectives for health and provide advice to breeders/owners regarding steps that may be taken to minimise the risk of the disease/disorders. Future breed-specific studies are recommended to report more precise prevalence estimates within more breeds.

Electronic supplementary material

The online version of this article (doi:10.1186/s40575-017-0047-3) contains supplementary material, which is available to authorized users.

Bayesian QTL analyses using pedigreed families of an outcrossing species, with application to fruit firmness in apple

Proof of concept of Bayesian integrated QTL analyses across pedigree-related families from breeding programs of an outbreeding species. Results include QTL confidence intervals, individuals' genotype probabilities and genomic breeding values. Bayesian QTL linkage mapping approaches offer the flexibility to study multiple full sib families with known pedigrees simultaneously. Such a joint analysis increases the probability of detecting these quantitative trait loci (QTL) and provide insight of the magnitude of QTL across different genetic backgrounds. Here, we present an improved Bayesian multi-QTL pedigree-based approach on an outcrossing species using progenies with different (complex) genetic relationships. Different modeling assumptions were studied in the QTL analyses, i.e., the a priori expected number of QTL varied and polygenic effects were considered. The inferences include number of QTL, additive QTL effect sizes and supporting credible intervals, posterior probabilities of QTL genotypes for all individuals in the dataset, and QTL-based as well as genome-wide breeding values. All these features have been implemented in the FlexQTL(™) software. We analyzed fruit firmness in a large apple dataset that comprised 1,347 individuals forming 27 full sib families and their known ancestral pedigrees, with genotypes for 87 SSR markers on 17 chromosomes. We report strong or positive evidence for 14 QTL for fruit firmness on eight chromosomes, validating our approach as several of these QTL were reported previously, though dispersed over a series of studies based on single mapping populations. Interpretation of linked QTL was possible via individuals' QTL genotypes. The correlation between the genomic breeding values and phenotypes was on average 90 %, but varied with the number of detected QTL in a family. The detailed posterior knowledge on QTL of potential parents is critical for the efficiency of marker-assisted breeding.

DNA fragmentation kinetics and postthaw motility of flow cytometric-sorted white-tailed deer sperm

This study examined DNA damage and postthaw motility of white-tailed deer sperm (n = 28) before and after sex selection and conventional sorting using MoFlo XDP SX flow cytometry. Semen samples from the same individuals were treated in 4 different ways: 1) chilled-extended sperm samples (without glycerol); 2) cryopreserved conventional samples, samples directly cryopreserved after the addition of extenders; 3) cryopreserved conventionally sorted samples, sorted samples to remove the dead sperm subpopulation; and 4) cryopreserved sex-sorted samples; sorted samples to remove the dead sperm subpopulation and separation of X- and Y-chromosome-bearing sperm. In all the cases (n = 6), conventional samples showed decreased postthaw motilities (43 ± 26%) when compared with X-sorted samples (59 ± 20%; P < 0.05) and Y-sorted samples (54 ± 20%; P > 0.05). The DNA fragmentation baseline was <5% for frozen-thawed conventional samples, but even less after sex sorting and conventional sorting: 2.4 and 1.7%, respectively. On the other hand, conventional samples showed greater (P < 0.05) DNA fragmentation than the sex-sorted sperm (n = 6) at 96 h (average of 4.8 ± 4.5% and 5.3 ± 4%, respectively). Conventionally sorted samples (n = 8) did not have greater (P > 0.05) DNA fragmentation when compared with the sex-sorted samples. Fragmentation of DNA on X-chromosome and Y-chromosome-bearing sorted sperm were not significantly different (n = 10, P > 0.05) after 96 h (2.6 ± 3.6% and 2.2 ± 0.5%, respectively). Future research should be implemented for examining the fertilizing potential of sex-sorted white-tailed deer sperm (e.g., AI fertility trials).

Methods and mortality results of a health survey of purebred dogs in the UK

OBJECTIVES

To collect information on the cause of death and longevity of dogs owned by members of the numerically largest breed clubs of 169 UK Kennel Club-recognised breeds.

METHODS

A cross-sectional study was carried out. Approximately 58,363 questionnaires were sent out to breed club members in 2004 (nine clubs failed to report the exact number of questionnaires sent out). Owners reported age at death and cause(s) of death for all dogs that had died within the previous 10 years.

RESULTS

A total of 13,741 questionnaires (24% response rate) containing information on 15,881 deaths were included in the analysis. Breed-specific response rates ranged from 64·7 to 4·5%. The median age at death was 11 years and 3 months (minimum=2 months, maximum=23 years and 5 months) and it varied by breed. The most common causes of death were cancer (n=4282, 27%), "old age" (n=2830, 18%) and cardiac conditions (n=1770, 11%).

CLINICAL SIGNIFICANCE

This survey shows breed differences in lifespan and causes of death, and the results support previous evidence that smaller breeds tend to have longer lifespan compared with larger breeds. Although many of the breeds in the study may not be representative of the general pedigree dog population in the UK, the results do contribute to the limited information currently available.

Biosynthetic Pathway for Veratryl Alcohol in the Ligninolytic Fungus Phanerochaete chrysosporium

Veratryl alcohol (VA) is a secondary metabolite of white-rot fungi that produce the ligninolytic enzyme lignin peroxidase. VA stabilizes lignin peroxidase, promotes the ability of this enzyme to oxidize a variety of physiological substrates, and is accordingly thought to play a significant role in fungal ligninolysis. Pulse-labeling and isotope-trapping experiments have now clarified the pathway for VA biosynthesis in the white-rot basidiomycete Phanerochaete chrysosporium. The pulse-labeling data, obtained with C-labeled phenylalanine, cinnamic acid, benzoic acid, and benzaldehyde, showed that radiocarbon labeling followed a reproducible sequence: it peaked first in cinnamate, then in benzoate and benzaldehyde, and finally in VA. Phenylalanine, cinnamate, benzoate, and benzaldehyde were all efficient precursors of VA in vivo. The isotope-trapping experiments showed that exogenous, unlabeled benzoate and benzaldehyde were effective traps of phenylalanine-derived C. These results support a pathway in which VA biosynthesis proceeds as follows: phenylalanine --> cinnamate --> benzoate and/or benzaldehyde --> VA.

Targeting invasion and egress: from tools to drugs?

A recent resurgence in the use of compounds to study essential biological processes raises important questions concerning the link between fundamental research and drug development. This article discusses many of the issues involved, in the context of host cell invasion and egress by parasites of the Phylum Apicomplexa. In addition, an overview of the key steps in invasion and egress is provided with a particular emphasis on potential parasite protein drug targets.

A challenging case of malignant hypercalcaemia

The investigation and management of patients presenting with hypercalcaemia is not always straightforward. We describe the case of a middleaged man presenting with severe symptomatic hypercalcaemia. The difficulties encountered here - in striving for biochemical and symptom control, and in establishing a definite diagnosis - are fortunately rare. The case illustrates the range of options in the treatment of severe hypercalcaemia, and highlights the use of haemodialysis in treatmentresistant cases.

Flow Cytometric Sorting of Fresh and Frozen-Thawed Spermatozoa in the Western Lowland Gorilla (Gorilla gorilla gorilla)

We adapted flow cytometry technology for high-purity sorting of X chromosome-bearing spermatozoa in the western lowland gorilla (Gorilla gorilla gorilla). Our objectives were to develop methodologies for liquid storage of semen prior to sorting, sorting of liquid-stored and frozen-thawed spermatozoa, and assessment of sorting accuracy. In study 1, the in vitro sperm characteristics of gorilla ejaculates from one male were unchanged (P > 0.05) after 8 hr of liquid storage at 15 degrees C in a non-egg yolk diluent (HEPES-buffered modified Tyrode's medium). In study 2, we examined the efficacy of sorting fresh and frozen-thawed spermatozoa using human spermatozoa as a model for gorilla spermatozoa. Ejaculates from one male were split into fresh and frozen aliquots. X-enriched samples derived from both fresh and frozen-thawed human semen were of high purity, as determined by fluorescence in situ hybridization (FISH; 90.7%+/-2.3%, overall), and contained a high proportion of morphologically normal spermatozoa (86.0%+/-1.0%, overall). In study 3, we processed liquid-stored semen from two gorillas for sorting using a modification of methods for human spermatozoa. The sort rate for enrichment of X-bearing spermatozoa was 7.3+/-2.5 spermatozoa per second. The X-enriched samples were of high purity (single-sperm PCR: 83.7%) and normal morphology (79.0%+/-3.9%). In study 4 we examined frozen-thawed gorilla semen, and the sort rate (8.3+/-2.9 X-bearing sperm/sec), purity (89.7%), and normal morphology (81.4%+/-3.4%) were comparable to those of liquid-stored semen. Depending on the male and the type of sample used (fresh or frozen-thawed), 0.8-2.2% of gorilla spermatozoa in the processed ejaculate were present in the X-enriched sample. These results demonstrate that fresh or frozen-thawed gorilla spermatozoa can be flow cytometrically sorted into samples enriched for X-bearing spermatozoa.

Identification of molecular markers linked to the mildew resistance gene Pl-d in apple

Powdery mildew poses a serious problem for apple growers, and resistance to the disease is a major objective in breeding programmes for cultivar improvement. As selective pressure allows pathogens to overcome previously reliable resistances, there is a need for the introduction of novel resistance genes into new breeding lines. This investigation is concerned with the identification of the first set of molecular markers linked to the gene for mildew resistance, Pl-d, from the accession 'D12'. As no prior information on the map position or markers for Pl-d were available, a bulked-segregant approach was used to test 49 microsatellite primers, 176 amplified fragment length polymorphism (AFLP) primers and 80 random amplified polymorphic DNA (RAPD) primers in a progeny segregating for Pl-d resistance, 'Fiesta' (susceptible) x A871-14 ('Worcester Pearmain' x 'D12'). The segregations of the markers identified in the resistant and susceptible bulks were scored in the progeny, then the recombination fractions between Pl-d and the most tightly linked markers were calculated and a map prepared. Three AFLP, one RAPD and two microsatellite markers were identified. One AFLP was developed into a sequence-characterised amplified region marker, while the microsatellites CH03C02 and CH01D03 were flanking markers, 7 and 11 recombination units, respectively, from Pl-d. Two more distant microsatellites on the same linkage group, CH01D09 and CH01G12, confirmed the orientation of the markers on the linkage group. These microsatellites place Pl-d on the bottom of linkage group 12 in published apple maps, a region where a number of other disease resistance genes have been identified.

Birth of lambs of a pre-determined sex after in vitro production of embryos using frozen–thawed sex-sorted and re-frozen–thawed ram spermatozoa

The characteristics and functional capacity of ram spermatozoa frozen–thawed prior to and after flow cytometric sorting was assessed after incubation (37 °C; 6 h),in vitrofertilisation (IVF), and transfer of fresh and vitrifiedin vitroproduced embryos. Frozen-thawed spermatozoa from two rams were allocated to four treatment groups: (i) non-sorted (Control); (ii) sorted (FS); (iii) sorted then re-frozen (FSF) and (iv) re-frozen control (FCF). Frozen-thawed samples were separated into X- and Y-chromosome bearing spermatozoa using a high-speed sperm sorter after density gradient centrifugation (X: 88 ± 1.5% and Y: 87 ± 1.1% purity). After 6 h incubation (37 °C), the percentage of motile spermatozoa was higher (P< 0.001) for FS (84 ± 2.0%) compared with all other treatments (Control: 36 ± 3.3%, FSF: 28 ± 3.1%, FCF: 20 ± 2.0%). In a sperm migration test greater numbers of FS spermatozoa penetrated 5 mm into the artificial cervical mucus compared with spermatozoa from all other treatments (152 ± 39.4 vs 31 ± 9.2 spermatozoa respectively;P< 0.05). Fertilisation and cleavage rates were higher (P< 0.05) forin vitromatured oocytes inseminated with Control compared with FSF spermatozoa. However, the Day 7 blastocyst development rate was higher for oocytes inseminated with FSF (62.2%) than FS and Control spermatozoa (52.7 and 50.0%;P< 0.05). The number of ewes pregnant (Day 60), lambing and thein vivoembryo survival rate was greater (P< 0.01) after the transfer of fresh embryos rather than vitrified embryos derived from X- and Y-spermatozoa (67.6, 64.7 and 41.2% vs 29.6, 25.9 and 14.8% respectively). Twenty-six of the 30 (86.7%) lambs derived from sex-sorted spermatozoa were of the correct sex. These results demonstrate that frozen–thawed ram spermatozoa can be sex-sorted for immediate or future use after re-cryopreservation and, in conjunction with IVF and embryo transfer, can be used to efficiently produce offspring of pre-determined sex.

Identification of SCAR markers linked to Pl-w mildew resistance in apple

Resistance to powdery mildew is an important objective for cultivar improvement programmes of apple and several different major genes for resistance to mildew are available. Molecular markers linked to such key traits can be used to screen progenies for resistant individuals. A progeny derived from the crab apple 'White Angel' (the source of Pl-w) was screened for resistance to mildew for two seasons in the glasshouse and four seasons in the field. DNA bulks of resistant and susceptible seedlings were screened with 176 AFLP primer combinations. Seven AFLP markers were identified that differentiated the bulks, and two of these markers were developed into SCARs, EM M01 and EM M02, mapping at 4.6 and 6.4 recombination units from Pl-w.

Flow cytometric sorting of frozen - thawed spermatozoa in sheep and non-human primates

Research was conducted in sheep to determine an effective preparation method for high-purity sorting of frozen–thawed spermatozoa. The efficacy of sorting frozen–thawed spermatozoa was then investigated in several non-human primate species. An aliquot of each ejaculate (three rams, three ejaculates per ram) was processed as a fresh control (FRESH). Frozen spermatozoa were thawed and prepared for sorting by no further processing (FT-NEAT), washing (FT-WASH) or gradient centrifugation (FT-GRADIENT) and evaluated for motility at 1 h post-staining and motility and acrosomal status at 0 and 4 h post-sorting. Samples were analysed using a high-speed cell sorter. High levels of purity for X- and Y-enriched samples were achieved for all treatments (85–92%). The percentage of motile spermatozoa before sorting was lower (P < 0.05) for frozen–thawed samples (FT-NEAT: 32.7 ± 2.5%; FT-WASH: 32.2 ± 3.3%; FT-GRADIENT: 73.9 ± 3.7%) compared with FRESH (83.3 ± 1.2%). Post-sorting, the percentage of motile spermatozoa before and after incubation for FT-NEAT (60.0 ± 5.1% and 27.2 ± 6.1% for 0 and 4 h, respectively) was lower than that for FRESH (87.8 ± 0.9% and 83.3 ± 1.2% for 0 and 4 h, respectively; P < 0.05), FT-WASH (80.0 ± 2.4% and 71.7 ± 3.6% for 0 and 4 h, respectively; P < 0.05) and FT-GRADIENT (84.4 ± 1.3% and 77.2 ± 1.7% for 0 and 4 h, respectively; P < 0.05). Vanguard sperm migration distance through artificial cervical mucus was lower (P < 0.05) for FT-NEAT (17.7 ± 1.7 mm) compared with FT-WASH (29.1 ± 3.8 mm) and FT-GRADIENT (28.4 ± 2.0 mm) and similar (P < 0.05) to FRESH (23.7 ± 1.8 mm). Sample preparation using a modified wash method enabled high-purity sorting (range 86–97% purity) of frozen–thawed epididymal spermatozoa in the baboon (Papio hamadryas), common marmoset (Callithrix jacchus) and common chimpanzee (Pan troglodytes). For all non-human primate species, sorted spermatozoa were progressively motile (marmoset: 20.5 ± 5.5%; baboon: 37.5 ± 2.5%; chimpanzee: 73.0 ± 2.0%), acrosome intact (marmoset: 68.5 ± 7.5%; baboon: 89.5 ± 1.5%; chimpanzee: 84.0 ± 1.0%) and able to penetrate an artificial cervical mucus. In summary, high-purity sorting of frozen–thawed ram and non-human primate spermatozoa with recovery of progressively motile, acrosome-intact spermatozoa was possible after processing to remove cryodiluent.

Biomechanical and histopathological changes in the support structures of bovine hooves around the time of first calving

Hooves were removed from heifers killed two weeks before calving (C-2), and four and twelve weeks post-calving (C+4 and C+12), and from age-matched maiden heifers. Segments were dissected from the anterior walls of lateral hind claws, to include horn, corium and bone, and the biomechanical properties were measured. There was reduced rigidity, both overall and at a physiologically appropriate displacement of 2 mm, and a greater displacement was required to reach initial and maximum support in the hooves of calving, compared with maiden, heifers. Histological examination revealed widened and distorted interdigitating laminae, progressing to C+12 in the hind claws, but with evidence of recovery in the front claws after C+4. Increased connective tissue strength from dorsal to ventral hoof segments was correlated with protein, proteoglycan, pro- and activated matrix metalloproteinase-2, and tissue inhibitors of metalloproteinases, and was inversely correlated with fat, water and collagen content. This implies that mechanical changes reflect alterations in the biochemistry of the connective tissue. This evidence supports the hypothesis that primary causal events associated with calving weaken the connective tissue of the hoof suspensory apparatus, leading to increased susceptibility to clinical lameness associated with sole ulcers and white line disease.

Pharmacokinetics and metabolism of a selective PDE5 inhibitor (UK-343,664) in rat and dog

1. UK-343,664 is a novel potent and selective PDE5 inhibitor. Plasma clearances in the male and female rat were high (120 and 54 ml min(-1) kg(-1)), giving rise to short elimination half-lives (0.2 and 0.3h respectively). Lower clearance in dog (14 ml min(-1) kg(-1)) was the primary factor resulting in a longer elimination half-life (3.7 h). The higher clearance in rat than dog was in agreement with in vitro metabolism rates in hepatic microsomes. 2. The volume of distribution was lower in rat (1.3-2.11 kg(-1)) compared with dog (4.61 kg(-1)) probably due to increased plasma protein binding in rat (96 versus 81% in dog). 3. Oral bioavailabilities were 2, 12 and 70% in the male and female rat and dog respectively. Tmax < or = 0.5 h in all animals. 4. In multiple oral dose studies, increased systemic exposure was seen with increasing dose up to doses of 200 mg kg(-1) in rat and 150 mg kg(-1) in dog. A marked super-proportional increase in the male rat indicated a capacity-limited clearance at high doses. 5. At the maximal dose of 200 mg kg(-1) in the female rat, no clinical signs were observed after 14 days of treatment. Only minimal signs were recorded in the male rat and dog at the highest dose levels investigated. 6. After single oral or intravenous doses of [14C]-UK-343,664, the majority of radioactivity was excreted in the faeces of both species. 7. UK-343,664 was extensively metabolized in both rat and dog. The major primary pathways in dog involved piperazine N-deethylation and loss of a two carbon fragment from the piperazine ring (N,N'-de-ethylation). More extensive metabolism in the rat included additional notable metalbolites arising from hydroxylation and lactamization of the piperazine ring, which were only minor metabolites in the dog.

A comparison of the foraging behaviour of the eastern pygmy-possum (Cercartetus nanus) and nectarivorous birds in a Banksia integrifolia woodland

The foraging behaviour of a non-flying mammal, the eastern pygmy-possum (Cercartetus nanus) and nectarivorous birds was compared in a Banksia integrifolia woodland at Wilson's Promontory National Park, Victoria, Australia. Exclusion experiments performed previously in this woodland indicate that both non-flying mammals and nectarivorous birds are important pollinators of B. integrifolia (Cunningham 1991: Oecologia 87: 86-90). In this study it is shown that C. nanus and nectarivorous birds employ different foraging tactics. Nectarivorous birds tended to move further between trees (Χ = 8.16 ± 1.06 m) than C. nanus (Χ = 5.64 ± 0.75 m), although these differences were not significant. Nectarivorous birds were attracted to trees with a significantly larger number of inflorescences (Χ = 36.55 ± 2.84) than C. nanus (Χ = 18.65 ± 2.95), and visited a significantly greater number of inflorescences per tree (Χ = 4.24 ± 0.35) than C. nanus (Χ = 2.33 ± 0.22). Although the two pollinator groups were attracted to banksia plants by different cues, once in the plants they visited an equal proportion of the available inflorescences.

The use of the isoenzymic marker gene Got-1 in the recognition of incompatibility S alleles in apple

The S incompatibility system of apple was confirmed through the application of the gene Got-1 for glutamate oxaloacetate transaminase as a marker for the S locus. The 11S alleles proposed by Kobel et al. (1939) were confirmed through anomalous segregations for Got-1 observed in 14 semi-compatible crosses and regular segregations observed in 2 fully compatible crosses. The S allele genotypes of 'Idared' (S 3 S 7), 'Cox' (S 5 S 9) and 'Fiesta' (S 3 S 5) were determined and found to fall within the original series. By associating parental incompatibility genotypes with the segregation of Got-1 alleles, we were able to deduce the coupling of S and Got-1 alleles in 9 varieties.

Parents' and children's expectations about Irlen (tinted) lenses

Additional unpublished data are presented from a study by Cotton and Evans in 1990 on the use of Irlen (tinted) lenses as an intervention for 22 children with a reading disability. These data reinforce the earlier conclusion that the random facilitatory effects of the lenses are very likely attributional and motivational in nature.

A comparative evaluation of iron clearance models

A comparative study of the non-iron-overloaded, bile duct-cannulated rat and of the Cebus monkey as iron-clearance models is presented. The ability of desferrioxamine, desferrithiocin, and a pyridoxal isonicotinoyl hydrazone (PIH) analogue to clear the metal from these two animals is evaluated. Data suggest that although rodents represent a viable first-line animal screen, there is no strict correspondence between the effectiveness of a chelator in rodents and that in primates. Rodent data should be interpreted carefully as it relates to potential human trials. Iron-loading response, the similarity between multiple human and Cebus serum and hematological values, and the ability to easily observe changes in behavioral patterns clearly render the Cebus monkey the best preclinical screen.

A review of the use of Irlen (tinted) lenses

Helen Irlen identified a syndrome defined as 'scotopic sensitivity' which it was claimed could be responsible for the inability of some people to read fluently and the symptoms of which could be ameliorated by the wearing of prescribed coloured lenses. The literature to date presents a confused and inconsistent picture concerning the use of the lenses. The literature (much of which is unpublished and difficult to obtain) is critically reviewed. Recent experimental evaluations of the lenses do not support the use of the lenses as a useful intervention for children with reading disabilities.