Tissue distribution and cellular localization of hsp56, an FK506-binding protein. Characterization using a highly specific polyclonal antibody.

Heat shock protein 56 (hsp56) has been shown to be involved in two cellular pathways, as an immunophilin for FK506 and as a component of steroid receptor complexes. To help define its role in these cellular pathways, we have developed UPJ56, a polyclonal antibody raised against hsp56 purified from Jurkat cells. In Western blot experiments, hsp56 was highly expressed in rat thymus, liver, and spleen, with low levels in lung and muscle. In immunofluorescence experiments using untreated LLC-PK1 cells, fibrillar staining was seen in the cytoplasm, suggesting a cytoskeletal localization of hsp56. The nuclei were brightly stained, except for the nucleoli. Confocal microscopy demonstrated that the staining was present in all planes of the nucleus. These results suggest that hsp56 is expressed in tissues enriched in steroid receptors and is highly expressed in tissues involved in T cell function. Furthermore, the localization of hsp56 with the cytoskeleton and throughout the nucleus is consistent with its association with steroid receptor complexes.     

A genomic evaluation of taxonomic trends through time in coast horned lizards (genus Phrynosoma)

Determining the boundaries between species and deciding when to describe new species are challenging practices that are particularly difficult in groups with high levels of geographic variation. The coast horned lizards (Phrynosoma blainvillii, Phrynosoma cerroense and P. coronatum) have an extensive geographic distribution spanning many distinctive ecological regions ranging from northern California to the Cape Region of Baja California, Mexico, and populations differ substantially with respect to external morphology across much of this range. The number of taxa recognized in the group has been reevaluated by herpetologists over 20 times during the last 180 years, and typically without the aid of explicit species delimitation methods, resulting in a turbulent taxonomy containing anywhere from one to seven taxa. In this study, we evaluate taxonomic trends through time by ranking 15 of these species delimitation models (SDMs) using coalescent analyses of nuclear loci and SNPs in a Bayesian model comparison framework. Species delimitation models containing more species were generally favoured by Bayesian model selection; however, several three‐species models outperformed some four‐ and five‐species SDMs, and the top‐ranked model, which contained five species, outperformed all SDMs containing six species. Model performance peaked in the 1950s based on marginal likelihoods estimated from nuclear loci and SNPs. Not surprisingly, SDMs based on genetic data outperformed morphological taxonomies when using genetic data alone to evaluate models. The de novo estimation of population structure favours a three‐population model that matches the currently recognized integrative taxonomy containing three species. We discuss why Bayesian model selection might favour models containing more species, and why recognizing more than three species might be warranted.     

Modelling the responses of Australian subtropical rainforest birds to changes in environmental conditions along elevational gradients

Montane birds face significant threats from a warming climate, so determining the environmental factors that most strongly influence the composition of such assemblages is of critical conservation importance. Changes in temperature and other environmental conditions along elevational gradients are known to influence the species richness and abundance of bird assemblages occupying mountains. However, the role of species‐specific traits in mediating the responses of bird species to changing conditions remains poorly understood. We aimed to determine whether different bird species responded differently to changing environmental conditions in a relatively understudied biodiversity hotspot in subtropical rainforest on the east coast of Australia. We examined patterns in avian species richness and abundance along two rainforest elevational gradients using monthly point counts between September 2015 and October 2016. Environmental data on temperature, wetness, canopy cover and canopy height were collected simultaneously, and trait information on body size and feeding guild membership for each bird species was obtained from the Handbook of Australian, New Zealand and Antarctic Birds. We used a generalized linear mixed modelling (GLMM) framework to determine the drivers of species richness and abundance and to quantify species’ trait–environment interactions. GLMMs indicated that temperature alone was significantly positively correlated with species richness and abundance. Species richness declined with increasing elevation. When modelling abundance, we found that feeding guild membership did not significantly affect species’ responses to environmental conditions. In contrast, the predicted abundance of a species was found to depend on its body size, due to significant positive interactions between this trait, temperature and canopy cover. Our findings indicate that large‐bodied birds are likely to increase in abundance more rapidly than small‐bodied birds with continued climatic warming. These results underline the importance of temperature as a driving factor of avian community assembly along environmental gradients.     

DIR: a novel DNA rearrangement associated with inverted repeats.

A novel DNA rearrangement has been characterised that is both a direct and inverted repeat.This rearrangement involves the 2-fold duplication of a plasmid sequence adjacent to the site of insertion of a long palindrome.The sequence of this rearrangement suggests that it has arisen by strand slippage from the leading to the lagging strand of the replication fork as a consequence of the presence of the long palindrome.     

A repetitive DNA sequence common to the different B chromosomes of the genus Brachycome

Dot-like micro B chromosomes of Brachycome dichromosomatica were analysed for their sequence composition. Southern hybridization patterns of a total micro B probe to genomic DNA from plants with and without micro Bs demonstrated that the micro Bs shared sequences with the A chromosomes. In addition to telomere, rDNA and common A and B chromosome sequences, a new B-specific, highly methylated tandem repeat (Bdm29) was detected. After in situ hybridization with Bdm29 the entire micro B chromosome was labelled and clustering of the condensed micro Bs could be observed at interphase. A high number of Bdm29-like sequences were also found in the larger B chromosomes of B. dichromosomatica and in other Bs within the genus Brachycome. Received: 30 May 1997; in revised form: 20 August 1997 / Accepted: 20 August 1997