Recovery from hybrid breakdown in a marine invertebrate is faster, stronger and more repeatable under environmental stress.

Understanding how environmental stress alters the consequences of hybridization is important, because the rate of hybridization and the likelihood of hybrid speciation both appear elevated in harsh, disturbed or marginal habitats. We assessed fitness, morphometrics and molecular genetic composition over 14 generations of hybridization between two highly divergent populations of the marine copepod Tigriopus californicus. Replicated, experimental hybrid populations in both control and high-salinity conditions showed a decline in fitness, followed by a recovery. Recovery was faster in the salinity stress treatment, returning to parental levels up to two generations earlier than in the control. This recovery was stable in the high-salinity treatment, whereas in the control treatment, fitness dropped back below parental levels at the final time point. Recovery in the high-salinity treatment was also stronger in terms of competitive fitness and heat-shock tolerance. Finally, consequences of hybridization were more repeatable under salinity stress, where among-replicate variance for survivorship and molecular genetic composition was lower than in the control treatment. In a system with low effective population sizes (estimates ranged from 17 to 63), where genetic drift might be expected to be the predominate force, strong selection under harsh environmental conditions apparently promoted faster, stronger and more repeatable recovery from depressed hybrid fitness.

From population genomics to conservation and management: a workflow for targeted analysis of markers identified using genome-wide approaches in Atlantic salmon Salmo salar.

A genotyping assay for the Ion Torrent Ion PGM platform was developed for fast and cost-effective targeted genotyping of key single nucleotide polymorphisms (SNPs) earlier identified using a genome-wide SNP array in Atlantic salmon Salmo salar. The method comprised a simple primer design step for multiplex-polymerase chain reaction (PCR), followed by two rounds of Ion Torrent Ion PGM sequencing to empirically evaluate marker efficiency in large multiplexes and to optimise or exclude them when necessary. Of 282 primer pairs initially tested, 217 were successfully amplified, indicating good amplification success (>75%). These markers included the sdy partial gene product to determine genetic sex, as well as three additional modules comprising SNPs for assessing neutral genetic variation (NSNP = 150), examining functional genetic variation associated with sea age at maturity (NSNP = 5), and for performing genetic subpopulation assignment (NSNP = 61). The assay was primarily developed to monitor long-term genetic changes in S. salar from the Teno River, but modules are likely suitable for application in a wide range of S. salar populations. Furthermore, the fast and versatile assay development pipeline offers a strategy for developing targeted sequencing assays in any species.

Fitness and morphological outcomes of many generations of hybridization in the copepod Tigriopus californicus.

Hybridization between genetically divergent populations is an important evolutionary process, with an outcome that is difficult to predict. We used controlled crosses and freely mating hybrid swarms, followed for up to 30 generations, to examine the morphological and fitness consequences of interpopulation hybridization in the copepod Tigriopus californicus. Patterns of fitness in two generations of controlled crosses were partly predictive of long-term trajectories in hybrid swarms. For one pair of populations, controlled crosses revealed neutral or beneficial effects of hybridization after the F1 generation, and hybrid swarm fitness almost always equalled or exceeded that of the midparent. For a second pair, controlled crosses showed F2 hybrid breakdown, but increased fitness in backcrosses, and hybrid swarm fitness deviated both above and below that of the parentals. Nevertheless, individual swarm replicates exhibited different fitness trajectories over time that were not related in a simple manner to their hybrid genetic composition, and fixation of fitter hybrid phenotypes was not observed. Hybridization did not increase overall morphological variation, and underlying genetic changes may have been masked by phenotypic plasticity. Nevertheless, one type of hybrid swarm exhibited a repeatable pattern of transgressively large eggsacs, indicating a positive effect of hybridization on individual fecundity. Additionally, both parental and hybrid swarms exhibited common phenotypic trends over time, indicating common selective pressures in the laboratory environment. Our results suggest that, in a system where much work has focused on F2 hybrid breakdown, the long-term fitness consequences of interpopulation hybridization are surprisingly benign.

Non-invasive prenatal diagnosis (NIPD) of cystic fibrosis: an optimized protocol using MEMO fluorescent PCR to detect the p.Phe508del mutation.

BACKGROUND: Analysis of cell-free foetal DNA (cff-DNA) in maternal plasma is very promising for early diagnosis of monogenic diseases; in particular, cystic fibrosis (CF). However, NIPD of single-gene disorders has been limited by the availability of suitable technical platforms and the need to set up patient or disease-specific custom-made approaches. METHODS: To make research applications more readily accessible to the clinic, we offer a simple assay combining two independent methods to determine the presence or absence of paternally inherited foetal allele p.Phe508del (the most frequent mutation in CF patients worldwide). The first method detects the presence or absence of a p.Phe508del allele by Mutant Enrichment with 3'-Modified Oligonucleotide PCR coupled to Fragment Length Analysis (MEMO-PCR-FLA). The second method detects the p.Phe508del allele with classical Multiplex Fluorescent PCR including five intragenic and extragenic STR markers of the CFTR locus and a specific SRY sequence. RESULTS: We collected 24 plasma samples from 23 women carrying foetuses at risk for CF and tested each sample using both methods. Our new procedures were successfully applied to 10 couples where fathers carried the p.Phe508del mutation and mothers were carrying a different mutation in the CFTR gene. These simple tests provided clear positive or negative results from the maternal plasma of the pregnant women. We confirmed the presence of cff-DNA in the studied samples by the identification of a tri-allelic DNA profile using a miniSTR kit. All results were correlated with chorionic villus sampling or amniocentesis analyses. CONCLUSIONS: This NIPD approach, easily set up in any clinical laboratory where prenatal diagnosis is routinely performed, offers many advantages over current methods: it is simple, rapid, and cost-effective. It opens up the possibility for testing a large number of couples with offspring at risk for CF.

Patterns of trait divergence between populations of the meadow grasshopper, Chorthippus parallelus.

To understand the process of speciation, we need to identify the evolutionary phenomena associated with divergence between populations of the same species. A powerful approach is to compare patterns of trait differences between populations differing in their evolutionary histories. A recent study of genetic divergence between populations of the meadow grasshopper Chorthippus parallelus, from different locations around Europe has allowed us to use this species to investigate which aspects of evolutionary history are associated with divergence in morphology and mating signals. During the last glaciation C. parallelus was confined to a number of refugia in southern Europe and has subsequently recolonized the northern part of the continent. This process of isolation followed by range expansion has created populations differing markedly in their evolutionary pasts--some have been isolated from one another for thousands of years, others have undergone repeated founder events, and others now live in sympatry with a closely related species. Using laboratory-reared grasshoppers from 12 different populations with a range of evolutionary histories, we quantify differences in morphology, chemical signals, and male calling-song. The observed pattern of divergence between these populations is then compared with the pattern predicted by hypotheses about what drives divergence. This comparison reveals that long periods in allopatry and processes associated with repeated founder events are both strongly associated with divergence.

The origins of premating reproductive isolation: testing hypotheses in the grasshopper Chorthippus parallelus.

There are many proposed routes for the origin of premating reproductive isolation, but few systematic studies aimed at testing their relative importance. Accumulated information about the biogeographical history of the European meadow grasshopper, Chorthippus parallelus, has allowed us to make a planned series of comparisons among populations aimed at distinguishing the contributions of some of these hypotheses. We have compared the effects on assortative mating of long-term isolation in glacial refugia, founder events during postglacial colonization, and sympatry with a closely related species. A likelihood-based analysis allowed us to separate effects of variation in male and female mating propensity among populations from variation in mate choice leading to assortative mating. All three effects contributed significantly to the overall variation in mating pattern in a set of 21 pairwise comparisons among seven populations. Male cuticular composition, but not other candidate signals, was significantly associated with the level of assortative mating. Of the hypotheses for the origin of reproductive isolation, only the predictions of the founder hypothesis explained a significant amount of the variation in assortative mating. This does not rule out the possiblity that there may be some other explanation. Having established the pattern of divergence, it is possible to generate hypotheses that explain our results at least as well as the founder hypothesis. However, because many such post hoc hypotheses are possible, they cannot be tested with this dataset. On this basis, our results favor the hypothesis that some aspect of the colonization process tends to accelerate divergence in mating signals leading to premating reproductive isolation. This could be accomplished through any one of several mechanisms. Colonization involves many bottlenecks as new populations are established at the edge of the range by long-distance migrants. Genetic effects may be important, but these bottlenecks may also alter the conditions under which mates are found and chosen, as suggested by Kaneshiro. At the same time, the colonizing populations may encounter novel environmental challenges.

Joint Commission standards for long-term care infection control: putting together the process element. Joint Commission on Accreditation of Healthcare Organizations.

Infection control in long-term care is being recognized more and more as the essential entity it has always been. As a surveyor for the long-term care program of the Joint Commission on Accreditation of Healthcare Organizations, I have noted that some confusion exists in the field as to what aspects of an infection control program are to be surveyed at specific standards. The standards are designed to allow flexibility to ensure that infection control programs meet the specific needs of the resident population and that these programs can continue to evolve. This article attempts to provide some clarity for the infection control professionals who are preparing for Joint Commission survey.

Infection control programs for long-term care.

1. Many infection control concerns are the same for both hospitals and long-term care facilities (LTCFs), but some are unique to LTCFs. The unique concerns seem to be in the area of "caring." 2. The Association for Practitioners in Infection Control (APIC) offers many educational opportunities for infection control practitioners (ICPs) in LTCFs. 3. The APIC Guideline for Infection Prevention and Control in the Long-Term Care Facility and interpretive assistance for implementing the Guideline in a variety of LTCF settings are available for ICPs.

Multistix versus laboratory urinalysis in the detection of urinary tract infection.

1. Difficulty with the early recognition of infection is a problem when caring for patients in an extended care facility. 2. The ability to quickly differentiate between asymptomatic bacteriuria and actual infection in male extended care patients is useful for guiding antibiotic therapy. 3. The nurse-administered nitrite test proved reliable as an indicator or urinary tract infection.

Universal precautions: how effective are they against methicillin-resistant Staphylococcus aureus?

1. Because MRSA is commonly carried asymptomatically, colonized patients and caregivers are usually not recognized. During outbreaks, colonized and infected patients act as reservoirs and caregivers become transient carriers. 2. Because universal precautions and body substance isolation were originally developed in response to the AIDS epidemic to meet the safety needs of hospital caregivers, the use of universal precautions in extended care facilities should be further studied and refined. 3. In planning for effective training, enforcement, and compliance with universal precautions, it is essential that employees understand not only the importance of protecting themselves, but also the need to prevent cross-infection. 4. If a patient has an MRSA respiratory tract infection, the environment, including the air, may become heavily contaminated. Caregivers should wear masks to prevent nasal colonization.

Treatment of a patient with a deep leg ulcer using Biatain Adhesive.

This article looks at the use of Biatain Adhesive, a new foam dressing from Coloplast which is manufactured by incorporating 3D polymer structures within the central pad. It is now available on the Drug Tariff. The article discusses the treatment of exuding wounds and highlights the benefits of Biatain Adhesive by focusing on the case of an 84-year-old woman who had a history of long-standing leg ulcers where previous dressings had failed to promote healing.

Very preterm birth: maternal experiences of the neonatal intensive care environment.

OBJECTIVE: Examine sources, predictors and child outcomes associated with neonatal intensive care unit (NICU)-related stress for mothers of infants born very preterm (VPT). STUDY DESIGN: Participants were 133 mothers of VPT infants admitted to a regional level-III NICU. At term equivalent, mothers completed the Parental Stressor Scale: NICU and were interviewed about their psychological well-being and family circumstances. Infant clinical data were also collected. At corrected age 4 years, 49 children were assessed for cognition, language and socio-emotional development. RESULT: Mothers reported moderate to low stress, with parental role alteration considered most stressful and parent-staff communications least stressful. Predictors of overall stress included maternal educational underachievement, stressful life events, postnatal depression and infant unsettled-irregular behavior. NICU-related stress was associated with child anxiety and poorer language development. CONCLUSION: Parental well-being is an important focus of care in the neonatal setting. Strategies are needed to optimize early engagement and reduce stress levels to assist improved child outcomes.

Discovery and characterization of a large number of diagnostic markers to discriminate Oncorhynchus mykiss and O. clarkii.

Hybridization of cutthroat trout and steelhead/rainbow trout is ubiquitous where they are sympatric, either naturally or owing to introductions. The ability to detect hybridization and introgression between the two species would be greatly improved by the development of more diagnostic markers validated across the two species' many phylogenetic lineages. Here, we describe 81 novel genetic markers and associated assays for discriminating the genomes of these sister species. These diagnostic nucleotide polymorphisms were discovered by sequencing of rainbow trout expressed sequence tags (ESTs) in a diverse panel of both cutthroat trout and steelhead/rainbow trout. The resulting markers were validated in a large number of lineages of both species, including all extant subspecies of cutthroat trout and most of the lineages of rainbow trout that are found in natural sympatry with cutthroat trout or used in stocking practices. Most of these markers (79%) distinguish genomic regions for all lineages of the two species, but a small number do not reliably diagnose coastal, westslope and/or other subspecies of cutthroat trout. Surveys of natural populations and hatchery strains of trout and steelhead found rare occurrences of the alternative allele, which may be due to either previous introgression or shared polymorphism. The availability of a large number of genetic markers for distinguishing genomic regions originating in these sister species will allow the detection of both recent and more distant hybridization events, facilitate the study of the evolutionary dynamics of hybridization and provide a powerful set of tools for the conservation and management of both species.

Development and evaluation of 200 novel SNP assays for population genetic studies of westslope cutthroat trout and genetic identification of related taxa.

DNA sequence data were collected and screened for single nucleotide polymorphisms (SNPs) in westslope cutthroat trout (Oncorhynchus clarki lewisi) and also for substitutions that could be used to genetically discriminate rainbow trout (O. mykiss) and cutthroat trout, as well as several cutthroat trout subspecies. In total, 260 expressed sequence tag-derived loci were sequenced and allelic discrimination genotyping assays developed from 217 of the variable sites. Another 50 putative SNPs in westslope cutthroat trout were identified by restriction-site-associated DNA sequencing, and seven of these were developed into assays. Twelve O. mykiss SNP assays that were variable within westslope cutthroat trout and 12 previously published SNP assays were also included in downstream testing. A total of 241 assays were tested on six westslope cutthroat trout populations (N = 32 per population), as well as collections of four other cutthroat trout subspecies and a population of rainbow trout. All assays were evaluated for reliability and deviation from Hardy-Weinberg and linkage equilibria. Poorly performing and duplicate assays were removed from the data set, and the remaining 200 assays were used in tests of population differentiation. The remaining markers easily distinguished the various subspecies tested, as evidenced by mean G(ST) of 0.74. A smaller subset of the markers (N = 86; average G(ST) = 0.40) was useful for distinguishing the six populations of westslope cutthroat trout. This study increases by an order of magnitude the number of genetic markers available for the study of westslope cutthroat trout and closely related taxa and includes many markers in genes (developed from ESTs).