A new technique for obtaining mitotic chromosome spreads from fishes in the field

This study presents an adaptation of current methodologies for preparing mitotic chromosomes from fishes, optimized for use in the field. The high-quality preparations obtained using this modified methodology is suitable for subsequent chromosomal analysis. Importantly, this method is particularly useful when specimen collection sites are far from research laboratories or when researchers are working with highly sensitive species that do not survive long outside of their natural habitats.     

Molecular cytogenetics and characterization of a ZZ/ZW sex chromosome system in Triportheus nematurus (Characiformes, Characidae)

Chromosomes of Triportheus nematurus, a fish species from family Characidae, were analyzed in order to establish the conventional karyotype, location of C-band positive heterochromatin, Ag-NORs, GC- and AT-rich sites, and mapping of 18S and 5S rDNA with fluorescence in situ hybridization (FISH). The diploid number found was 2n = 52 chromosomes in both males and females. However, the females presented a pair of differentiated heteromorphic chromosomes, characterizing a ZZ/ZW sex chromosome system. The Z chromosome was metacentric and the largest one in the karyotype, bearing C-positive heterochromatin at pericentromeric and telomeric regions. The W chromosome was middle-sized submetacentric, appearing mostly heterochromatic after C-banding and presenting heterogeneous heterochromatin composed of GC- and AT-rich regions revealed by fluorochrome staining. Ag-NORs were also GC-rich and surrounded by heterochromatic regions, being located at the secondary constriction on the short arms of the second chromosome pair, in agreement with 18S rDNA sites detected with FISH. The 18S and 5S rDNA were aligned in tandem, representing an uncommon situation in fishes. The results obtained reinforce the basal condition of the ZZ/ZW sex system in the genus Triportheus, probably arisen prior to speciation in the group.     

Diversification of a ZZ/ZW sex chromosome system in Characidium fish (Crenuchidae, Characiformes)

Karyotype and other chromosomal markers of Characidium cf. gomesi were analyzed using conventional (Giemsa-staining, Ag-NOR and C-banding) and molecular (Fluorescent in situ hybridization (FISH) with 18S and 5S rDNA biotinylated probes) techniques. Both sexes had invariably diploid chromosome number 2n = 50 while karyotypes of males and females differed. That of male consisted of 32 metacentric + 18 submetacentric chromosomes and that of female consisted 31 metacentric + 18 submetacentric + 1 subtelocentric chromosomes. The Z chromosome was medium-sized metacentric, while W was highly heterochromatinized subtelocentric element. NORs as revealed by Ag-staining were situated at 2–7 telomeric regions while FISH with 18S probes showed consistently 10 signals at telomeric regions. FISH with 5S rDNA probe showed constantly signals at one metacentric pair. Distribution of centromeric heterochromatin was mostly in all chromosome pairs, besides some telomeric sites. The common origin of the sex chromosome system of ZZ/ZW type in the karyotypes of other representatives of the genus analyzed so far might be hypothesized based on biogeography and partial phylogeny of the group.     

The effects of care bundles on patient outcomes: a systematic review and meta-analysis

Background

Care bundles are a set of three to five evidence-informed practices performed collectively and reliably to improve the quality of care. Care bundles are used widely across healthcare settings with the aim of preventing and managing different health conditions. This is the first systematic review designed to determine the effects of care bundles on patient outcomes and the behaviour of healthcare workers in relation to fidelity with care bundles.

Methods

This systematic review is reported in line with the PRISMA statement for reporting systematic reviews and meta-analyses. A total of 5796 abstracts were retrieved through a systematic search for articles published between January 1, 2001, to February 4, 2017, in the Cochrane Central Register for Controlled Trials, MEDLINE, EMBASE, British Nursing Index, CINAHL, PsychInfo, British Library, Conference Proceeding Citation Index, OpenGrey trials (including cluster-randomised trials) and non-randomised studies (comprising controlled before-after studies, interrupted time series, cohort studies) of care bundles for any health condition and any healthcare settings were considered. Following the removal of duplicated studies, two reviewers independently screen 3134 records. Three authors performed data extraction independently. We compared the care bundles with usual care to evaluate the effects of care bundles on the risk of negative patient outcomes. Random-effect models were used to further explore the effects of subgroups.

Results

In total, 37 studies (6 randomised trials, 31 controlled before-after studies) were eligible for inclusion. The effect of care bundles on patient outcomes is uncertain. For randomised trial data, the pooled relative risk of negative effects between care bundle and control groups was 0.97 [95% CI 0.71 to 1.34; 2049 participants]. The relative risk of negative patient outcomes from controlled before-after studies favoured the care bundle treated groups (0.66 [95% CI 0.59 to 0.75; 119,178 participants]). However, using GRADE, we assessed the certainty of all of the evidence to be very low (downgraded for risk of bias, inconsistency, indirectness).

Conclusions

Very low quality evidence from controlled before-after studies suggests that care bundles may reduce the risk of negative outcomes when compared with usual care. By contrast, the better quality evidence from six randomised trials is more uncertain.

Trial registration

PROSPERO, CRD42016033175

     

Estimates for worldwide laboratory animal use in 2005

Animal experimentation continues to generate public and political concern worldwide. Relatively few countries collate and publish animal use statistics, yet this is a first and essential step toward public accountability and an informed debate, as well as being important for effective policy-making and regulation. The implementation of the Three Rs (replacement, reduction and refinement of animal experiments) should be expected to result in a decline in animal use, but without regular, accurate statistics, this cannot be monitored. Recent estimates of worldwide annual laboratory animal use are imprecise and unsubstantiated, ranging from 28-100 million. We collated data for 37 countries that publish national statistics, and standardised these against the definitions of 'animals', 'purposes' and 'experiments' used in European Union Directive 86/609/EEC. We developed and applied a statistical model, based on publication rates, for a further 142 countries. This yielded our most conservative estimate of global animal use: 58.3 million animals in 179 countries. However, this figure excludes several uses and forms of animals that are included in the statistics of some countries. With the data available, albeit for only a few countries, we also produced, by extrapolation, a more comprehensive global estimate that includes animals killed for the provision of tissues, animals used to maintain genetically-modified strains, and animals bred for laboratory use but killed as surplus to requirements. For a number of reasons that are explained, this more-comprehensive figure of 115.3 million animals is still likely to be an underestimate.     

Assessing predation risk: optimal behaviour and rules of thumb

We look at a simple model in which an animal makes behavioural decisions over time in an environment in which all parameters are known to the animal except predation risk. In the model there is a trade-off between gaining information about predation risk and anti-predator behaviour. All predator attacks lead to death for the prey, so that the prey learns about predation risk by virtue of the fact that it is still alive. We show that it is not usually optimal to behave as if the current unbiased estimate of the predation risk is its true value. We consider two different ways to model reproduction; in the first scenario the animal reproduces throughout its life until it dies, and in the second scenario expected reproductive success depends on the level of energy reserves the animal has gained by some point in time. For both of these scenarios we find results on the form of the optimal strategy and give numerical examples which compare optimal behaviour with behaviour under simple rules of thumb. The numerical examples suggest that the value of the optimal strategy over the rules of thumb is greatest when there is little current information about predation risk, learning is not too costly in terms of predation, and it is energetically advantageous to learn about predation. We find that for the model and parameters investigated, a very simple rule of thumb such as 'use the best constant control' performs well.     

Microassay analyses of protein glycosylation

To accurately characterize the carbohydrate moieties of oligosaccharide chains in glycosylated proteins, it is necessary to distinguish exactly which types of oligosaccharides are present at which site. We describe lectin overlay assays, which take advantage of the ability of lectins to distinguish between different types of glycoproteins via recognition of terminal sugars, thus allowing the chain type and peripheral antigenic components to be determined. Three microassays involving lectins are reported in this paper: non-proteasetreated intact glycoproteins; glycopeptides released by prior digestion of the glycoprotein and then separated by HPLC; and release of sugars from glycoproteins by hydrazinolysis and then coupling them to a multivalent support.     

Phototrophic Fe(II) oxidation promotes organic carbon acquisition by Rhodobacter capsulatus SB1003

Anoxygenic phototrophic Fe(II) oxidation is usually considered to be a lithoautotrophic metabolism that contributes to primary production in Fe-based ecosystems. In this study, we employed Rhodobacter capsulatus SB1003 as a model organism to test the hypothesis that phototrophic Fe(II) oxidation can be coupled to organic carbon acquisition. R. capsulatus SB1003 oxidized Fe(II) under anoxic conditions in a light-dependent manner, but it failed to grow lithoautotrophically on soluble Fe(II). When the strain was provided with Fe(II)-citrate, however, growth was observed that was dependent upon microbially catalyzed Fe(II) oxidation, resulting in the formation of Fe(III)-citrate. Subsequent photochemical breakdown of Fe(III)-citrate yielded acetoacetic acid that supported growth in the light but not the dark. The deletion of genes (RRC00247 and RRC00248) that encode homologs of atoA and atoD, required for acetoacetic acid utilization, severely impaired the ability of R. capsulatus SB1003 to grow on Fe(II)-citrate. The growth yield achieved by R. capsulatus SB1003 in the presence of citrate cannot be explained by lithoautotrophic growth on Fe(II) enabled by indirect effects of the ligand [such as altering the thermodynamics of Fe(II) oxidation or preventing cell encrustation]. Together, these results demonstrate that R. capsulatus SB1003 grows photoheterotrophically on Fe(II)-citrate. Nitrilotriacetic acid also supported light-dependent growth on Fe(II), suggesting that Fe(II) oxidation may be a general mechanism whereby some Fe(II)-oxidizing bacteria mine otherwise inaccessible organic carbon sources.