Ecological niche breadth and microhabitat guild structure in temperate Australian reptiles: Implications for natural resource management in endangered grassy woodland ecosystems

Ecological theory predicts that species with narrow niche requirements (habitat specialists) are more vulnerable to anthropocentric disturbances than those with broad niche requirements (habitat generalists). Hence, understanding a species ecological niche and guild membership would serve as a valuable management tool for providing a priori assessments of a species extinction risk. It also would help to forecast a species capacity to respond to land use change, as what might be expected to occur under financial incentive schemes to improve threatened ecological vegetation communities. However, basic natural history information is lacking for many terrestrial species, particularly reptiles in temperate regions of the world. To overcome this limitation, we collated 3527 reptile observations from 52 species across an endangered woodland ecoregion in south‐eastern Australia and examined ecological niche breadth and microhabitat guild structure. We found 30% of species had low ecological niche values and were classified as habitat specialists associated with large eucalypt trees, woody debris, surface rock or rocky outcrops. Cluster analysis separated species into six broad guilds based on microhabitat similarity. Approximately 80% of species belonged to guilds associated with old growth vegetation attributes or non‐renewable litho‐resources such as surface rock or rocky outcrops. Our results suggest that agri‐environment schemes that focus purely on grazing management are unlikely to provide immediate benefits to broad suites of reptiles associated with old growth vegetation and litho‐resources. Our classification scheme will be useful for identifying reptile species that are potentially vulnerable to anthropocentric disturbances and may require alternative strategies for improving habitat suitability and reptile conservation outcomes in grassy woodland ecosystems.     

Enhanced cortical excitability in grapheme-color synesthesia and its modulation

Synesthesia is an unusual condition characterized by the over-binding of two or more features and the concomitant automatic and conscious experience of atypical, ancillary images or perceptions. Previous research suggests that synesthetes display enhanced modality-specific perceptual processing, but it remains unclear whether enhanced processing contributes to conscious awareness of color photisms. In three experiments, we investigated whether grapheme-color synesthesia is characterized by enhanced cortical excitability in primary visual cortex and the role played by this hyperexcitability in the expression of synesthesia. Using transcranial magnetic stimulation, we show that synesthetes display 3-fold lower phosphene thresholds than controls during stimulation of the primary visual cortex. We next used transcranial direct current stimulation to discriminate between two competing hypotheses of the role of hyperexcitability in the expression of synesthesia. We demonstrate that synesthesia can be selectively augmented with cathodal stimulation and attenuated with anodal stimulation of primary visual cortex. A control task revealed that the effect of the brain stimulation was specific to the experience of synesthesia. These results indicate that hyperexcitability acts as a source of noise in visual cortex that influences the availability of the neuronal signals underlying conscious awareness of synesthetic photisms.     

Molecular genetics and mechanisms of disease in distal hereditary motor neuropathies: insights directing future genetic studies

The distal hereditary motor neuropathies (dHMNs) are a clinically and genetically heterogeneous group of disorders that primarily affect motor neurons, without significant sensory involvement. New dHMN genes continue to be identified. There are now 11 causative genes described for dHMN, and an additional five genetic loci with unidentified genes. This genetic heterogeneity has further delineated the classification of dHMN, which was previously classified according to mode of inheritance, age at onset, and additional complicating features. Some overlap between phenotypically distinct forms of dHMN is also apparent. The mutated genes identified to-date in dHMN include HSPB1, HSPB8, HSPB3, DCTN1, GARS, PLEKHG5, BSCL2, SETX, IGHMBP2, ATP7A and TRPV4. The pathogenesis of mutations remains to be fully elucidated, however common pathogenic mechanisms are emerging. These include disruption of axonal transport, RNA processing defects, protein aggregation and inclusion body formation, disrupted calcium channel activity, and loss of neuroprotective signalling. Some of these dHMN genes are also mutated in Charcot-Marie-Tooth (CMT) disease and spinal muscular atrophy (SMA). This review examines the growing number of identified dHMN genes, discusses recent insights into the functions of these genes and possible pathogenic mechanisms, and looks at the increasing overlap between dHMN and the other neuropathies CMT2 and SMA.     

Characterization and functional activity of murine monoclonal antibodies specific for α1,6-glucan chain of Helicobacter pylori lipopolysaccharide

Background: The outer core region of H. pylori lipopolysaccharide (LPS) contains α1,6‐glucan previously shown to contribute to colonizing efficiency of a mouse stomach. The aim of the present study was to generate monoclonal antibodies (mAbs) specific for α1,6‐glucan and characterize their binding properties and functional activity. Materials and Methods: BALB/c mice were injected intraperitoneally with 10⁸ formalin‐fixed H. pylori O:3 0826::Kan cells 3× over 56 days to achieve significant titer. Anti‐α1,6‐glucan‐producing hybridomas were screened by indirect ELISA using purified H. pylori O:3 0826::Kan LPS. One clone, 1C4F9, was selected for further characterization. The specificities of mAbs were determined by indirect and inhibition ELISA using structurally defined H. pylori LPS and synthetic oligosaccharides, and whole‐cell indirect ELISA (WCE) of clinical isolates. They were further characterized by indirect immunofluorescent (IF) microscopy and their functional activity in vitro determined by serum bactericidal assays against wild‐type and mutant strains of H. pylori. Results: The generated anti‐α1,6‐glucan IgM, 1C4F9, has demonstrated an excellent specificity for the glucan chain containing 5 to 6 α1,6‐linked glucose residues and showed surface accessibility by IF microscopy with H. pylori cells adherent to gastric adenocarcinoma cells monolayers. Of 38 isolates from Chile, 17 strains reacted with antiglucan mAbs in WCE (OD₄₅₀ ≥ 0.2). Bactericidal activity was observed against selective wild‐type and mutant H. pylori strains exhibiting OD₄₅₀ values of ≥0.45 in WCE. Conclusions: Anti‐α1,6‐glucan mAbs could have potential application in typing and surveillance of H. pylori isolates as well as offer insights into structural requirements for the development of LPS‐based vaccine against H. pylori infections.     

The ratio and allometric scaling of speed, power, and strength in elite male rugby union players

This study compared the effectiveness of ratio and allometric scaling for normalizing speed, power, and strength in elite male rugby union players. Thirty rugby players (body mass [BM] 107.1 ± 10.1 kg, body height [BH] 187.8 ± 7.1 cm) were assessed for sprinting speed, peak power during countermovement jumps and squat jumps, and horizontal jumping distance. One-repetition maximum strength was assessed during a bench press, chin-up, and back squat. Performance was normalized using ratio and allometric scaling (Y/X), where Y is the performance, X, the body size variable (i.e., BM or BH), and b is the power exponent. An exponent of 1.0 was used during ratio scaling. Allometric scaling was applied using proposed exponents and derived exponents for each data set. The BM and BH variables were significantly related, or close to, performance during the speed, power and/or strength tests (p < 0.001-0.066). Ratio scaling and allometric scaling using proposed exponents were effective in normalizing performance (i.e., no significant correlations) for some of these tests. Allometric scaling with derived exponents normalized performance across all the tests undertaken, thereby removing the confounding effects of BM and BH. In terms of practical applications, allometric scaling with derived exponents may be used to normalize performance between larger rugby forwards and smaller rugby backs, and could provide additional information on rugby players of similar body size. Ratio scaling may provide the best predictive measure of performance (i.e., strongest correlations).     

Serotonin transporter genotype (5-HTTLPR) predicts utilitarian moral judgments

Background

The psychological and neurobiological processes underlying moral judgment have been the focus of extensive recent research. Here we show that serotonin transporter (5-HTTLPR) genotype predicts responses to moral dilemmas featuring foreseen harm to an innocent.

Methodology/Principal Findings

Participants in this study judged the acceptability of actions that would unintentionally or intentionally harm an innocent victim in order to save others'' lives. An analysis of variance revealed a genotype × scenario interaction, F(2, 63) = 4.52, p = .02. Results showed that, relative to long allele homozygotes (LL), carriers of the short (S) allele showed particular reluctance to endorse utilitarian actions resulting in foreseen harm to an innocent individual. LL genotype participants rated perpetrating unintentional harm as more acceptable (M = 4.98, SEM = 0.20) than did SL genotype participants (M = 4.65, SEM = 0.20) or SS genotype participants (M = 4.29, SEM = 0.30). No group differences in moral judgments were observed in response to scenarios featuring intentional harm.

Conclusions/Significance

The results indicate that inherited variants in a genetic polymorphism that influences serotonin neurotransmission influence utilitarian moral judgments as well. This finding is interpreted in light of evidence that the S allele is associated with elevated emotional responsiveness.     

CHDL: a cadherin-like domain in Proteobacteria and Cyanobacteria

We identified a cadherin-like domain (CHDL) using computational analysis. The CHDL domain is mostly distributed in Proteobacteria and Cyanobacteria, although it is also found in some eukaryotic proteins. Prediction of three-dimensional protein folding indicated that the CHDL domain has an immunoglobulin beta-sandwich fold and belongs to the cadherin superfamily. The CHDL domain does not have LDRE and DxNDN motifs, which are conserved in the cadherin domain, but has three other motifs: PxAxxD, DxDxD and YT-V/I-S/T-D, which might contribute to forming a calcium-binding site. The identification of this cadherin-like domain indicates that the cadherin superfamily may exhibit wider sequence and structural diversity than previously appreciated. Domain architecture analysis revealed that the CHDL domain is also associated with other adhesion domains as well as enzyme domains. Based on computational analysis and previous experimental data, we predict that the CHDL domain has calcium-binding and also carbohydrate-binding activity.