High temperature-mediated adaptations in plant architecture require the bHLH transcription factor PIF4

Exposure of Arabidopsis plants to high temperature (28 degrees C) results in a dramatic change in plant development. Responses to high temperature include rapid extension of plant axes, leaf hyponasty, and early flowering. These phenotypes parallel plant responses to the threat of vegetational shade and have been shown to involve the hormone auxin. In this work, we demonstrate that high temperature-induced architectural adaptations are mediated through the bHLH transcriptional regulator PHYTOCHROME INTERACTING FACTOR 4 (PIF4). Roles for PIF4 have previously been established in both light and gibberellin (GA) signaling, through interactions with phytochromes and DELLA proteins, respectively. Mutants deficient in PIF4 do not display elongation responses or leaf hyponasty upon transfer to high temperature. High temperature-mediated induction of the auxin-responsive gene IAA29 is also abolished in these plants. An early flowering response to high temperature is maintained in pif4 mutants, suggesting that architectural and flowering responses operate via separate signaling pathways. The role of PIF4 in temperature signaling does not, however, appear to operate through interaction with either phytochrome or DELLA proteins, suggesting the existence of a novel regulatory mechanism. We conclude that PIF4 is an important component of plant high temperature signaling and integrates multiple environmental cues during plant development.

Qualitative differences in the N-acetyl-D-galactosaminyltransferases produced by human A1 and A2 genes

This study describes the kinetic properties of N-acetyl-D-galactosaminyltransferase in serum from subjects with blood groups A(1) and A(2). When the A(1) and A(2) enzymes were compared, with lacto-N-fucopentaose I and 2'-fucosyllactose as acceptors, the enzymes differed in their cation requirements, pH optima, and K(m) values. The two acceptors competed for the same transferase. Mixing experiments showed that the lower activity of the A(2) enzyme could not be attributed to a modifier or inhibitor in serum. It was concluded that the A(1) and A(2) enzymes differ qualitatively.

Effectiveness of strategies to disseminate and implement clinical guidelines for the management of impacted and unerupted third molars in primary dental care, a cluster randomised controlled trial

OBJECTIVE

To investigate the effectiveness and cost-effectiveness of different guideline implementation strategies, using the Scottish Intercollegiate Guidelines Network (SIGN) Guideline 42 "Management of unerupted and impacted third molar teeth" (published 2000) as a model.

DESIGN

A pragmatic, cluster RCT (2x2 factorial design).

SUBJECTS

Sixty-three dental practices across Scotland. Clinical records of all 16-24-year-old patients over two, four-month periods in 1999 (pre-intervention) and 2000 (post-intervention) were searched by a clinical researcher blind to the intervention group. Data were also gathered on the costs of the interventions.

INTERVENTIONS

Group 1 received a copy of SIGN 42 Guideline and had an opportunity to attend a postgraduate education course (PGEC). In addition to this, group 2 received audit and feedback (A and F). Group 3 received a computer aided learning (CAL) package. Group 4 received A and F and CAL. PRINCIPAL OUTCOME MEASUREMENT: The proportion of patients whose treatment complied with the guideline.

RESULTS

The weighted t-test for A and F versus no A and F (P=0.62) and CAL versus no CAL (P=0.76) were not statistically significant. Given the effectiveness results (no difference) the cost effectiveness calculation became a cost-minimisation calculation. The minimum cost intervention in the trial consisted of providing general dental practitioners (GDPs) with guidelines and the option of attending PGEC courses. Routine data which subsequently became available showed a Scotland-wide fall in extractions prior to data collection.

CONCLUSION

In an environment in which pre-intervention compliance was unexpectedly high, neither CAL nor A and F increased the dentists' compliance with the SIGN guideline compared with mailing of the guideline and the opportunity to attend a postgraduate course. The cost of the CAL arm of the trial was greater than the A and F arm. Further work is required to understand dental professionals' behaviour in response to guideline implementation strategies.

Unequal subfamily proportions among honey bee queen and worker brood

Queens from three colonies of feral honey bees, Apis mellifera were removed and placed in separate nucleus colonies. For each colony, eggs and larvae were taken from the nucleus and placed in the main hive on each of 3-4 consecutive weeks. Workers in the queenless parts selected young larvae to rear as queens. Queen pupae, together with the surrounding worker pupae, were removed from each colony and analysed at two to three microsatellite loci to determine their paternity. In all three colonies, the paternity of larvae chosen by the bees to rear as queens was not a random sample of the paternities in the worker brood, with certain subfamilies being over-represented in queens. These results support an important prediction of kin selection theory: when colonies are queenless, unequal relatedness within colonies could lead to the evolution of reproductive competition, that is some subfamilies achieving greater reproductive success than others. The mechanism by which such dominance is achieved could be through a system of kin recognition and nepotism, but we conclude that genetically based differential attractiveness of larvae for rearing as queens is more likely.Copyright 1997 The Association for the Study of Animal BehaviourCopyright 1997The Association for the Study of Animal Behaviour.

Conversion of incomplete antibodies to direct agglutinins by mild reduction: evidence for segmental flexibility within the Fc fragment of immunoglobulin G

Reduction of interchain disulfide bonds converted some IgG incomplete antibodies to direct hemagglutinins. This conversion occurred whether antibody was free in solution or bound to the red-cell surface. Reduced antibody permitted to reoxidize in air no longer behaved as a direct agglutinin; reversion to an incomplete antibody did not occur when reoxidation was prevented by S-alkylation. These results suggest that mild reduction of the antibody imparts sufficient freedom to permit bridging between cells and are interpreted as evidence that the interheavy-chain disulfide bonds restrict segmental flexibility within the Fc fragment of IgG.

A and B and A1Leb substances in glycosphingolipid fractions of human serum

A and B and A1Leb substances were adsorbed onto red cells exposed to glycosphingolipid fractions prepared from the serum of group A and B and A1,Le(a minus b plus) donors. Group O cells exposed to fractions prepared from the serum of group A or B donors were agglutinated by an IgM cross-reacting antibody present in some group O sera. Cells exposed to fractions from A1,Le(a minus b plus) serum were agglutinated by anti-A1Leb. The amount of A substance in the fractions was related to the A subtype (A1 or A2) and to the Lewis and secretor phenotype of the donor. The uptake of blood-group substances from the lipid fractions was inhibited by the addition of whole serum to the fractions.

A Low-Cost Method of Skin Swabbing for the Collection of DNA Samples from Small Laboratory Fish

Fin clipping of live fish under anesthesia is widely used to collect samples for DNA extraction. An alternative, potentially less invasive, approach involves obtaining samples by swabbing the skin of nonanesthetized fish. However, this method has yet to be widely adopted for use in laboratory studies in the biological and biomedical sciences. Here, we compare DNA samples from zebrafish Danio rerio and three-spined sticklebacks Gasterosteus aculeatus collected via fin clipping and skin swabbing techniques, and test a range of DNA extraction methods, including commercially available kits and a lower-cost, in-house method. We verify the method for polymerase chain reaction analysis, and examine the potential risk of cross contamination between individual fish that are netted together. We show that swabbing, which may not require the use of anesthesia or analgesics, offers a reliable alternative to fin clipping. Further work is now required to determine the relative effects of fin clipping and swabbing on the stress responses and subsequent health of fish, and hence the potential of swabbing as a refinement to existing DNA sampling procedures.

Elevated levels of the IgG2 subclass in serum from patients with a history of destructive periodontal disease. A case-control study

The levels of the 4 subclasses of IgG were estimated in the serum from 35 patients with a history of chronic periodontitis and 35 matched controls. The levels of IgG2 were significantly (P less than 0.019) elevated in the patients (3.756 g l-1) compared to the controls (2.882 g l-1). The data suggest that the predominant antibody response to periodontal pathogens in periodontitis may be directed against carbohydrate or glycolipid antigens.

Red blood cell survival studies in patients with anti-Cha, anti-Yka, anti-Ge, and anti-Vel

The survival of red blood cells, which were strongly incompatible in vitro, was measured in five patients whose serum contained an antibody to a high-frequency antigen. In the two patients with anti-Cha, and in the patient with anti-Yka, the cells survived normally. In the patient with anti-Ge, a small proportion of the cells was destroyed at an increased rate during the first 24 hours, but the remaining cells survived normally. In the patient with anti-Vel, the injected cells were rapidly destroyed.

Evidence that blood group A antigen on lymphocytes is derived from the plasma

Serum from group O volunteers, who had been injected with porcine A blood group substance, was used in lymphocytotoxicity tests. Positive reactions were obtained only with lymphocytes of group A secretors; the strongest reactors were Le(a--b--). The same group O sera reacted with group O lymphocytes which had been exposed to a glycosphingolipid fraction prepared from the plasma of A,Le(a--b--) secretors. These reactions were specifically inhibited by A substance. It is suggested that, unlike the A antigen on red cells, the A antigen detected in lymphocytotoxicity tests is entirely derived from the plasma.

Wound-factor-induced and cell cycle phase-dependent expression of 9E3/CEF4, the avian gro gene

The gro genes encode for secreted proteins with sequence homologies to inflammatory mediators. Little is known about the function of these proteins or their regulation. The chicken gro (9E3/CEF4) is expressed abundantly in the cells of proliferating cultures but at very low levels in confluent cultures. In vivo, this gene is expressed in connective tissue and overexpressed at sites of injury, especially in areas of neovascularization. Here we provide a bridge between these observations by examining in culture the effect on 9E3 expression and DNA synthesis induced by cell damage and by addition of factors known to be released on wounding. We mimicked wounding by scraping swaths across confluent cultures of embryonic fibroblasts and determined the time dependence of expression of 9E3 mRNA and incorporation of 3H-thymidine. We find that 9E3 is (1) transiently expressed after "wounding" or serum-stimulation; (2) expressed in a cell cycle phase-dependent manner; it is triggered during the G0-G1 transition or early in G1 and subsides during S-phase; and (3) stimulated to high levels by a-fibroblast growth factor (aFGF), bFGF, transforming growth factor alpha (TGF alpha), and TGF beta, to intermediate levels by platelet-derived growth factor and not stimulated by epidermal growth factor. We also find that cells that are constantly cycling do not express 9E3, indicating that they skip either the portion of the cell cycle where 9E3 is induced or that they constitutively express a repressor of transcription or an RNA-degrading enzyme. Taken together, these observations suggest that the product of this gene could play more than one role in vivo. For example, in normal tissues the 9E3 protein could be involved in the exit of cells from the resting stage, whereas during wound healing the secreted protein or its cleavage products also could play a role in angiogenesis.

A further example of human blood group chimaerism

Blood group chimaerism was detected in a healthy fertile woman, not known to be a twin. Her peripheral lymphocytes had a male karyotype (46/XY); fibroblasts cultured from her skin had a female karyotype (46/XX). The mechanism of chimaerism could not be established.

The zebrafish histamine H3 receptor modulates aggression, neural activity and forebrain functional connectivity

AIM

Aggression is a behavioural trait characterized by the intention to harm others for offensive or defensive purposes. Neurotransmitters such as serotonin and dopamine are important mediators of aggression. However, the physiological role of the histaminergic system during this behaviour is currently unclear. Here, we aimed to better understand histaminergic signalling during aggression by characterizing the involvement of the histamine H3 receptor (Hrh3).

METHODS

We have generated a novel zebrafish Hrh3 null mutant line using CRISPR-Cas9 genome engineering and investigated behavioural changes and alterations to neural activity using whole brain Ca2+ imaging in zebrafish larvae and ribosomal protein S6 (rpS6) immunohistochemistry in adults.

RESULTS

We show that genetic inactivation of the histamine H3 receptor (Hrh3) reduces aggression in zebrafish, an effect that can be reproduced by pharmacological inhibition. In addition, hrh3-/- zebrafish show behavioural impairments consistent with heightened anxiety. Larval in vivo whole brain Ca2+ imaging reveals higher neuronal activity in the forebrain of mutants, but lower activity in specific hindbrain areas and changes in measures of functional connectivity between subregions. Adult hrh3-/- zebrafish display brain region-specific neural activity changes in response to aggression of both key regions of the social decision-making network, and the areas containing histaminergic neurons in the zebrafish brain.

CONCLUSION

These results highlight the importance of zebrafish Hrh3 signalling for aggression and anxiety and uncover the brain areas involved. Targeting this receptor might be a potential novel therapeutic route for human conditions characterized by heightened aggression.

Human blood-group A- and H-specified glycosyltransferase levels in the sera of newborn infants and their mothers

The level of blood-group A1-specified alpha,3'-N-acetyl-D-galactosaminyl-transferase in the serum of recently-delivered women was found to be appreciably lower than the level of this enzyme in the serum of non-pregnant adults and of newborn infants; a similar but less striking decrease was observed in the levels of the A2-specified alpha,3'-N-acetyl-D-galactosaminyltransferase and the H-specified alpha,2'-L-fucosyltransferase. Although the red cells of newborn infants are known to have relatively few A and H antigen sites, the serum of neonates was found to have a level of A1- and A2-dependent N-acetylgalactosaminyltransferases and H-dependent fucosyltransferase as high as, if not higher than, the serum of non-pregnant adults. This finding is compatible with the fact that the haemopoietic tissue contributes only about 20% of the serum transferase level.

Flow-mediated plasticity in the expression of stickleback nesting glue genes

Nest construction is an essential component of the reproductive behavior of many species, and attributes of nests – including their location and structure – have implications for both their functional capacity as incubators for developing offspring, and their attractiveness to potential mates. To maximize reproductive success, nests must therefore be suited to local environmental conditions. Male three-spined sticklebacks (Gasterosteus aculeatus) build nests from collected materials and use an endogenous, glue-like multimeric protein – “spiggin” – as an adhesive. Spiggin is encoded by a multigene family, and differential expression of spiggin genes potentially allows plasticity in nest construction in response to variable environments. Here, we show that the expression of spiggin genes is affected significantly by both the flow regime experienced by a fish and its nesting status. Further, we show the effects of flow on expression patterns are gene-specific. Nest-building fish exhibited consistently higher expression levels of the three genes under investigation (Spg-a,Spg-1, and Spg-2) than non-nesting controls, irrespective of rearing flow treatment. Fish reared under flowing-water conditions showed significantly increased levels of spiggin gene expression compared to those reared in still water, but this effect was far stronger for Spg-a than for Spg-1 or Spg-2. The strong effect of flowing water on Spg-a expression, even among non-nesters, suggests that the increased production of spiggin – or of spiggin rich in the component contributed by Spg-a – may allow more rapid and/or effective nest construction under challenging high flow conditions.

Oestrogenic pollutants promote the growth of a parasite in male sticklebacks

Aquatic environments are especially susceptible to anthropogenic chemical pollution. Yet although knowledge on the biological effects of pollutants on aquatic organisms is increasing, far less is known about how ecologically-important interspecific interactions are affected by chemicals. In particular, the consequences of anthropogenic pollution for the interaction of hosts and parasites are poorly understood. Here, we examine how exposure to 17β-oestradiol (E2)-a natural oestrogen and a model endocrine disrupting chemical (EDC) -affects infection susceptibility and emergent infection phenotypes in an experimental host-parasite system; three spined sticklebacks (Gasterosteus aculeatus) infected with the common, debilitating cestode Schistocephalus solidus. We exposed individual sticklebacks to a 0ngl(-1) (control), 10ngl(-1) or 100ngl(-1) E2 treatment before feeding them infective stages of S. solidus. E2 exposure significantly elevated vitellogenin (VTG) levels-a biomarker of exposure to xenoestrogens-in both female and male fish, and reduced their body condition. Susceptibility to parasite infection was unaffected by EDC exposure; however, E2 treatment and fish sex interacted significantly to determine the growth rate of parasites, which grew quickest in male hosts held under the higher (100ngl(-1)) E2 treatment. Tissue VTG levels and parasite mass correlated positively across the whole sample of experimentally infected fish, but separate regressions run on the male and female datasets demonstrated a significant relationship only among male fish. Hence, among males-but not females-elevated VTG levels elicited by E2 exposure led to more rapid parasite growth. We outline plausible physiological mechanisms that could explain these results. Our results demonstrate that oestrogenic pollutants can alter host-parasite interactions by promoting parasite growth, and that male hosts may be disproportionately affected. Because ecologically-relevant effects of infection on host antipredator responses, growth, energetics and reproductive development all depend on parasite mass in this host-parasite system, our results indicate that EDCs can mediate the ecological consequences of infections. We therefore consider the implications of our results for the ecology of hosts and parasites in polluted environments.

Monogamous bivalency of IgG antibodies. I. Deficiency of branched ABHI-active oligosaccharide chains on red cells of infants causes the weak antiglobulin reactions in hemolytic disease of the newborn due to ABO incompatibility

This study shows that monogamous bivalency of human IgG anti-A and anti-B is necessary to maintain sensitization of red cells in the antiglobulin test. On red cells of infants and of adults of i phenotype, the known deficiency of branched ABHI-active oligosaccharide chains limits monogamous bivalency, and these accounts for the relatively weak direct antiglobulin reactions in hemolytic disease of the newborn due to ABO incompatbility. One corollary of this finding is that there is strong biologic selection against the transition on fetal red cells from the straight-chain i phenotype to branched-chain I phenotype, since such branching of cell-surface oligosaccharide chains would compromise ABO-incompatible pregnancies.

adgrl3.1-deficient zebrafish show noradrenaline-mediated externalizing behaviors, and altered expression of externalizing disorder-candidate genes, suggesting functional targets for treatment

Externalizing disorders (ED) are a cause of concern for public health, and their high heritability makes genetic risk factors a priority for research. Adhesion G-Protein-Coupled Receptor L3 (ADGRL3) is strongly linked to several EDs, and loss-of-function models have shown the impacts of this gene on several core ED-related behaviors. For example, adgrl3.1-/- zebrafish show high levels of hyperactivity. However, our understanding of the mechanisms by which this gene influences behavior is incomplete. Here we characterized, for the first time, externalizing behavioral phenotypes of adgrl3.1-/- zebrafish and found them to be highly impulsive, show risk-taking in a novel environment, have attentional deficits, and show high levels of hyperactivity. All of these phenotypes were rescued by atomoxetine, demonstrating noradrenergic mediation of the externalizing effects of adgrl3.1. Transcriptomic analyses of the brains of adgrl3.1-/- vs. wild-type fish revealed several differentially expressed genes and enriched gene clusters that were independent of noradrenergic manipulation. This suggests new putative functional pathways underlying ED-related behaviors, and potential targets for the treatment of ED.

Skin swabbing protocol to collect DNA samples from small-bodied fish species

Fish species are commonly used as experimental models in the laboratory. DNA is routinely collected from these animals to permit identification of their genotype. The current standard procedure to sample DNA is fin clipping, which involves anaesthetising individuals and removing a portion of the caudal fin. While fin clipping reliably generates good quality DNA samples for downstream applications, there is evidence that it can alter health and welfare, and impact the fish's behaviour. This in turn can result in greater variation in the data collected. In a recent study we adapted a skin swabbing protocol to collect DNA from small-bodied fish, including sticklebacks and zebrafish, without the use of analgesics, anaesthetics or sharp instruments. A rayon-tipped swab was used to collect mucus from the flank of the fish, which was then used for DNA extraction. We subsequently demonstrated that compared to fin clipping, skin swabbing triggered fewer changes in stress axis activation and behaviour. We also found that gene expression and behaviour data collected from swabbed fish were less variable than similar data collected from fish that had been fin clipped. This potentially allows smaller sample sizes in experimental groups to be used after skin swabbing, thereby reducing animal use. Here we provide a detailed protocol explaining how to collect DNA samples from small laboratory fish using skin swabs.