Researching little-known species: the African bat Otomops martiensseni (Chiroptera: Molossidae)

Listed as 'vulnerable' by the International Union for theConservation of Nature, the molossid bat Otomopsmartiensseni occurs widely in Africa and, according to someauthorities, in Madagascar. Apart from a few known cave roosts, there are fewrecords of O. martiensseni, although around Durban, SouthAfrica, the species is common and roosts in buildings. Originally described asthree species, populations of O. martiensseni differsignificantly in size (length of forearm) between East Africa and Durban orMadagascar, but not between Durban and Madagascar. Seventeen buildings used asroosts by O. martiensseni averaged 34.5 ± 15.8years old. In the Durban area, bats entered roosts by landing andcrawling. Roost populations ranged from 7 to 29 individuals, typicallyconsisting of one adult male, several adult females and young (bats withunossified epiphyses), suggesting a harem social structure. The ratio of adultfemales to young was virtually 1:1, and among young the ratio of males:femalesaveraged 2:1. Radio-tracking showed that individuals used several day and nightroosts, and foraged widely in a landscape dominated by sugarcane and urbandevelopment. The echolocation and many social calls of O.martiensseni are readily audible to human observers, allowing anon-contact, low technology method for monitoring the local distribution andactivity of these bats. Although listed as a species of special concern inKwaZulu Natal, there these bats appear to be candidates for inclusion on a'blue' list of species, ones showing stabilized or increasedabundance. We recommend that O. martiensseni be recognizedas a 'flagship' species in the Durban area, r epresenting theresilience of nature.     

Auditory-based defence against gleaning bats in neotropical katydids (Orthoptera: Tettigoniidae)

Neotropical katydids (Orthoptera: Tettigoniidae) are preyed on by gleaning bats, which are known to use male calling songs to locate them. At least one katydid species has been reported to stop singing in response to bat echolocation calls. To investigate the relationship between this behavioural defence and ecological and sensory factors, we surveyed calling song characteristics, song cessation in response to the echolocation calls of a sympatric gleaning bat (Trachops cirrhosus), and T-cell responses (an auditory interneuron sensitive to ultrasound) in five katydid species from Panamá. The two katydid species that stopped singing in response to bat calls (Balboa tibialis and Ischnomela gracilis, Pseudophyllinae) also had the highest T-cell spike number and rate in response to these stimuli. The third pseudophylline species (Docidocercus gigliotosi) did not reliably cease singing and had low T-cell spiking activity. Neoconocephalus affinis (Copiphorinae) produced continuous calling song, possibly preventing males from hearing the bat during singing, and did not show a behavioural response despite high T-cell activity in response to bat calls. Steirodon rufolineatum (Phaneropterinae) did not cease singing and differed in T-cell activity compared to the other species. T-cell function might not be conserved in katydids, and evidence for this idea is discussed.     

Molecular evidence of the survival of subterranean amphipods (Arthropoda) during Ice Age underneath glaciers in Iceland

Two endemic groundwater arthropod crustacean species, Crangonyx islandicus and Crymostygius thingvallensis, were recently discovered on the mid‐Atlantic volcanic island of Iceland. The extent of morphological differences from closest relatives, endemism, along with the geographic isolation of Iceland and its complete coverage by glaciers 21 000 years ago, suggests that these two species have survived glaciation periods in sub‐glacial refugia. Here we provide strong support for this hypothesis by an analysis of mitochondrial genetic variation within Crangonyx islandicus. Our results show that the species is divided into several distinct monophyletic groups that are found along the volcanic zone in Iceland, which have been separated by 0.5 to around 5 million years. The genetic divergence between groups reflects geographic distances between sampling sites, indicating that divergence occurred after the colonization of Iceland. The genetic patterns, as well as the dependency of genetic variation on distances from the tectonic plate boundary and altitude, points to recent expansion from several refugia within Iceland. This presents the first genetic evidence of multicellular organisms as complex as crustacean amphipods which have survived glaciations beneath an ice sheet. This survival may be explained by geothermal heat linked to volcanic activities, which may have maintained favourable habitats in fissures along the tectonic plate boundary in Iceland during glaciations.     

Neural evolution in the bat-free habitat of Tahiti: partial regression in an anti-predator auditory system

Noctuid moths endemic to the mountains of Tahiti have evolved in an environment without bats and these insects have lost a defensive behaviour against these predators, the acoustic startle response (ASR). The ASR in noctuid moths is presumed to be activated by a single auditory receptor neuron (A2 cell) and we report that while this cell still exists in endemic species and possesses similar sensitivity thresholds compared to the A2 cell of recently introduced species, it exhibits reduced firing activity to ASR-evoking sounds. This partial neural regression suggests that the evolutionary disappearance of the ASR in these insects is incomplete and that sensoribehavioural integration decays gradually following the removal of stabilizing selective forces.     

Vitamin B6 in Plasma and Cerebrospinal Fluid of Children

Background

Over the past years, the essential role of vitamin B6 in brain development and functioning has been recognized and genetic metabolic disorders resulting in functional vitamin B6 deficiency have been identified. However, data on B6 vitamers in children are scarce.

Materials and Methods

B6 vitamer concentrations in simultaneously sampled plasma and cerebrospinal fluid (CSF) of 70 children with intellectual disability were determined by ultra performance liquid chromatography-tandem mass spectrometry. For ethical reasons, CSF samples could not be obtained from healthy children. The influence of sex, age, epilepsy and treatment with anti-epileptic drugs, were investigated.

Results

The B6 vitamer composition of plasma (pyridoxal phosphate (PLP) > pyridoxic acid > pyridoxal (PL)) differed from that of CSF (PL > PLP > pyridoxic acid > pyridoxamine). Strong correlations were found for B6 vitamers in and between plasma and CSF. Treatment with anti-epileptic drugs resulted in decreased concentrations of PL and PLP in CSF.

Conclusion

We provide concentrations of all B6 vitamers in plasma and CSF of children with intellectual disability (±epilepsy), which can be used in the investigation of known and novel disorders associated with vitamin B6 metabolism as well as in monitoring of the biochemical effects of treatment with vitamin B6.     

APOE ε4 moderates abnormal CSF-abeta-42 levels,while neurocognitive impairment is associated with abnormal CSF tau levels in HIV+ individuals – a cross-sectional observational study

Background

Cerebrospinal fluid (CSF) biomarkers Aβ1-42, t-tau and p-tau have a characteristic pattern in Alzheimer’s Disease (AD). Their roles in HIV-associated neurocognitive disorder (HAND) remains unclear.

Methods

Adults with chronic treated HIV disease were recruited (n = 43, aged 56.7 ± 7.9; 32% aged 60+; median HIV duration 20 years, >95% plasma and CSF HIV RNA <50 cp/mL, on cART for a median 24 months). All underwent standard neuropsychological testing (61% had HAND), APOE genotyping (30.9% carried APOE ε4 and 7.1% were ε4 homozygotes) and a lumbar puncture. Concentrations of Aβ1-42, t-tau and p-tau were assessed in the CSF using commercial ELISAs. Current neurocognitive status was defined using the continuous Global Deficit Score, which grades impairment in clinically relevant categories. History of HAND was recorded. Univariate correlations informed multivariate models, which were corrected for nadir CD4-T cell counts and HIV duration.

Results

Carriage of APOE ε4 predicted markedly lower levels of CSF Aβ1-42 in univariate (r = -.50; p = .001) and multivariate analyses (R² = .25; p < .0003). Greater levels of neurocognitive impairment were associated with higher CSF levels of p-tau in univariate analyses (r = .32; p = .03) and multivariate analyses (R² = .10; p = .03). AD risk prediction cut-offs incorporating all three CSF biomarkers suggested that 12.5% of participants had a high risk for AD. Having a CSF-AD like profile was more frequent in those with current (p = .05) and past HIV-associated dementia (p = .03).

Conclusions

Similarly to larger studies, APOE ε4 genotype was not directly associated with HAND, but moderated CSF levels of Aβ1-42 in a minority of participants. In the majority of participants, increased CSF p-tau levels were associated with current neurocognitive impairment. Combined CSF biomarker risk for AD in the current HIV+ sample is more than 10 times greater than in the Australian population of the same age. Larger prospective studies are warranted.

     

Refinement of the Multiple Exostoses Locus (EXT2) to a 3-cM Interval on Chromosome 11

Hereditary multiple exostoses (EXT) is an autosomal dominant skeletal disorder characterized by the formation of multiple exostoses on the long bones. EXT is genetically heterogeneous, with at least three loci involved: one (EXT1) in the Langer-Giedion region on 8q23-q24, a second (EXT2) in the pericentromeric region of chromosome 11, and a third (EXT3) on chromosome 19p. In this study, linkage analysis in seven extended EXT families, all linked to the EXT2 locus, refined the localization of the EXT2 gene to a 3-cM region flanked by D11S1355 and D11S1361/D11S554. This implies that the EXT2 gene is located at the short arm of chromosome 11, in band 11p11-p12. The refined localization of EXT2 excludes a number of putative candidate genes located in the pericentromeric region of chromosome 11 and facilitates the process of isolating the EXT2 gene.     

Distribution and conservation of mobile elements in the genus Drosophila

Essentially nothing is known of the origin, mode of transmission, and evolution of mobile elements within the genus Drosophila. To better understand the evolutionary history of these mobile elements, we examined the distribution and conservation of homologues to the P, I, gypsy, copia, and F elements in 34 Drosophila species from three subgenera. Probes specific for each element were prepared from D. melanogaster and hybridized to genomic DNA. Filters were washed under conditions of increasing stringency to estimate the similarity between D. melanogaster sequences and their homologues in other species. The I element homologues show the most limited distribution of all elements tested, being restricted to the melanogaster species group. The P elements are found in many members of the subgenus Sophophora but, with the notable exception of D. nasuta, are not found in the other two subgenera. Copia-, gypsy-, and F-element homologues are widespread in the genus, but their similarity to the D. melanogaster probe differs markedly between species. The distribution of copia and P elements and the conservation of the gypsy and P elements is inconsistent with a model that postulates a single ancient origin for each type of element followed by mating-dependent transmission. The data can be explained by horizontal transmission of mobile elements between reproductively isolated species.      

Optimizing industrial‐scale coral reef restoration: comparing harvesting wild coral spawn slicks and transplanting gravid adult colonies

Accelerating coral reef restoration is a global challenge that has been attempted around the world. Previous attempts show varying levels of success at localized scales, but comparisons of cost and benefits to evaluate large‐scale reef restoration approaches are lacking. Here, we compare two large‐scale restoration approaches: the harvesting, development, and release of wild coral spawn slicks onto a target reef, with the transplantation of gravid coral colonies to provide a seed population and local source of larvae. Comparisons incorporate the best available information on demographic rates to estimate population growth, beginning at embryo production to colony maturity 4 years following deployment. Cost‐effectiveness is considered in a coarse manner. The harvesting, development, and controlled release of coral spawn slicks is anticipated to achieve large‐scale restoration of coral communities with low‐impact technology at low cost per colony. Harvesting wild spawn slicks has the potential to (1) transport billions of larvae up to thousands of kilometers that (2) are relevant to coral restoration efforts at vast geographical scales while (3) benefitting from the use of technology with extremely low impact on wild populations and (4) retaining natural genetic and species diversity needed to enhance the resilience of restored communities. Transplanting colonies is most useful from reefs designated to be impacted by infrastructural development by providing an opportunity for transfer to high value zones, from dedicated nurseries, and for brooding species. Our contribution provides insights into critical elements of both concepts, and we highlight information gaps in parameter uncertainties.