Socio-environmental and endocrine influences on developmental and caste-regulatory gene expression in the eusocial termite \u3cem\u3eReticulitermes flavipes\u3c/em\u3e

BACKGROUND: Strict regulation of caste differentiation, at the molecular level, is thought to be important to maintain social structure in insect societies. Previously, a number of extrinsic and intrinsic factors have been shown to influence caste composition in termite colonies. One important factor is the influence of nestmates; in particular, soldier termites are known to inhibit hormone-dependent worker-to-soldier differentiation. However, soldier influences on nestmates at the molecular level are virtually unknown. Here, to test the hypothesis that soldiers can influence nestmate gene expression, we investigated the impact of four treatments on whole-body gene expression in totipotent Reticulitermes flavipes workers: (i) juvenile hormone III (JHIII; a morphogenetic hormone), (ii) soldier head extracts (SHE), (iii) JHIII+SHE, and (iv) live soldiers. RESULTS: Using quantitative-real-time PCR we determined the expression patterns of 49 previously identified candidate genes in response to the four treatments at assay days 1, 5, and 10. Thirty-eight total genes from three categories (chemical production/degradation, hemolymph protein, and developmental) showed significant differential expression among treatments. Most importantly, SHE and live soldier treatments had a significant impact on a number of genes from families known to play roles in insect development, supporting previous findings and hypotheses that soldiers regulate nestmate caste differentiation via terpene primer pheromones contained in their heads. CONCLUSIONS: This research provides new insights into the impacts that socio-environmental factors (JH, soldiers, primer pheromones) can have on termite gene expression and caste differentiation, and reveals a number of socially-relevant genes for investigation in subsequent caste differentiation research

Socio-environmental and endocrine influences on developmental and caste-regulatory gene expression in the eusocial termite Reticulitermes flavipes

Background Strict regulation of caste differentiation, at the molecular level, is thought to be important to maintain social structure in insect societies. Previously, a number of extrinsic and intrinsic factors have been shown to influence caste composition in termite colonies. One important factor is the influence of nestmates; in particular, soldier termites are known to inhibit hormone-dependent worker-to-soldier differentiation. However, soldier influences on nestmates at the molecular level are virtually unknown. Here, to test the hypothesis that soldiers can influence nestmate gene expression, we investigated the impact of four treatments on whole-body gene expression in totipotent Reticulitermes flavipes workers: (i) juvenile hormone III (JHIII; a morphogenetic hormone), (ii) soldier head extracts (SHE), (iii) JHIII+SHE, and (iv) live soldiers. Results Using quantitative-real-time PCR we determined the expression patterns of 49 previously identified candidate genes in response to the four treatments at assay days 1, 5, and 10. Thirty-eight total genes from three categories (chemical production/degradation, hemolymph protein, and developmental) showed significant differential expression among treatments. Most importantly, SHE and live soldier treatments had a significant impact on a number of genes from families known to play roles in insect development, supporting previous findings and hypotheses that soldiers regulate nestmate caste differentiation via terpene primer pheromones contained in their heads. Conclusions This research provides new insights into the impacts that socio-environmental factors (JH, soldiers, primer pheromones) can have on termite gene expression and caste differentiation, and reveals a number of socially-relevant genes for investigation in subsequent caste differentiation research

Using metadata record graphs to understand controlled vocabulary and keyword usage for subject representation in the UNT theses and dissertations collection

An important function of metadata for electronic theses and dissertations (ETDs) is supporting the discovery of related documents through linking of data values in the fields of metadata records. While benefits of the ETD format allow for full-text searching, metadata is still an important and necessary component of the global ETD infrastructure because it is often not possible to share the full documents in aggregations such as the Global ETD Search for the Networked Digital Library of Theses and Dissertations. The metadata field that has the most potential to assist users in discovery is the subject field used to represent what a resource is about. Over the years there has been much discussion of the value of author-generated keywords versus adding subject terms from controlled vocabularies by information professionals as documents are submitted to the University repository. This research seeks to explore this problem with the help of network analysis method not used for such analyzes before by building and analyzing metadata record graphs for the University of North Texas theses and dissertations. This paper reports on the characteristics of keyword-based and controlled-vocabulary-based metadata record networks and discussions insights that can be gained from this approach to metadata quality analysis. This research seeks to explore this problem with the help of network analysis method not used for such analyzes before by building and analyzing metadata record graphs for the University of North Texas theses and dissertations. This paper reports on the characteristics of keyword-based and controlled-vocabulary-based metadata record networks and discussions insights that can be gained from this approach to metadata quality analysis. This research seeks to explore this problem with the help of network analysis method not used for such analyzes before by building and analyzing metadata record graphs for the University of North Texas theses and dissertations. This paper reports on the characteristics of keyword-based and controlled-vocabulary-based metadata record networks and discussions insights that can be gained from this approach to metadata quality analysis

External Second Gate-Fourier Transform Ion Mobility Spectrometry.

Ion mobility spectrometry (IMS) is recognized as one of the most sensitive and versatile techniques for the detection of trace levels of organic vapors. IMS is widely used for detecting contraband narcotics, explosives, toxic industrial compounds and chemical warfare agents. Increasing threat of terrorist attacks, the proliferation of narcotics, Chemical Weapons Convention treaty verification as well as humanitarian de-mining efforts has mandated that equal importance be placed on the analysis time as well as the quality of the analytical data. (1) IMS is unrivaled when both speed of response and sensitivity has to be considered. (2) With conventional (signal averaging) IMS systems the number of available ions contributing to the measured signal to less than 1%. Furthermore, the signal averaging process incorporates scan-to-scan variations decreasing resolution. With external second gate Fourier Transform ion mobility spectrometry (FT-IMS), the entrance gate frequency is variable and can be altered in conjunction with other data acquisition parameters to increase the spectral resolution. The FT-IMS entrance gate operates with a 50% duty cycle and so affords a 7 to 10-fold increase in sensitivity. Recent data on high explosives are presented to demonstrate the parametric optimization in sensitivity and resolution of our system

Anxiety and intellectual functioning in autistic children:A systematic review and meta-analysis

Autistic children experience higher levels of anxiety than their peers. Making appropriate diagnoses of anxiety disorders and providing effective treatment for these children is particularly difficult. Inconsistent evidence suggests that levels of anxiety in autistic children are related to intellectual functioning. We provide the first meta-analysis of this evidence. A systematic search identified 49 papers for review. These papers included measures of anxiety and intelligence quotient in 18,430 autistic children. Studies employing correlations showed evidence of a significant relationship between intelligence quotient and anxiety in autistic children: children with higher intelligence quotient scored higher on measures of anxiety. Studies directly comparing groups of autistic children with and without intellectual disability also supported this conclusion. Most studies employing other designs also supported this finding. Employing a quality assessment framework identified common threats to validity. Many studies used measures of anxiety that were not validated across the samples they measure. This was most notable for those autistic children with an intellectual disability. It is vital that future research determines whether the identified relationship between intelligence quotient and anxiety reflects something important in the mechanism for anxiety in autistic children, or quantifies the lack of sensitivity of our measures of anxiety across different groups

Effects of Soldier-Derived Terpenes on Soldier Caste Differentiation in the Termite (Reticulitermes flavipes)

Primer pheromones play key roles in regulating division of labor, which is one of the most fundamental and defining aspects of insect sociality. Primer pheromones are chemical messengers that transmit hormone-like messages among colony members; in recipients these messages can either induce or suppress phenotypic caste differentiation. Here, we investigated soldier-caste-derived chemicals as possible primer pheromones in the lower termite Reticulitermes flavipes, a species for which no primer pheromones have yet been identified. We determined that soldier head extracts (SHE), when provided to totipotent workers along with the insect morphogenetic juvenile hormone (JH), significantly enhanced soldier caste differentiation. When applied alone, however, SHE had no impacts on caste differentiation, survivorship, or any other aspect of worker biology. These findings support that soldier-derived chemicals serve as primer pheromones which enhance the action of the endogenous morphogenetic hormone JH. Thus, SHE chemicals apparently have no effect when received under natural conditions by non-receptive individuals with presumably low JH titers. Gas chromatography-mass spectrometry analysis identified two terpenes as the most plentiful components of R. flavipes SHE. Through GC-MS and NMR analyses, these terpenes were identified as γ-cadinene and its corresponding aldehyde, g-cadinenal. Validative bioassays with commercially available cadinene confirmed its activity. However, several other previously identified terpenes were also significantly active. These findings reveal a novel primer pheromone-like function for soldier-derived terpenes in termites, and further suggest convergent evolution of terpene functions in enhancing JH-dependent soldier caste differentiation

Molecular dynamics simulation of shocks in porous TATB crystals

We report molecular dynamics results on the shock structure of 2-D crystals of triaminotrinitrobenzene (TATB). We find that the shock front broadens to approx. 30 nm in materials with a 20% random void distribution. As expected from bulk experiments, the shock velocity decreases with increasing porosity and the temperature behind the shock front increases with increasing porosity. Shock equilibration times increase from 1 ps to greater than 10 ps

The fossil record of early tetrapods: worker effort and the end-Permian mass extinction

It is important to understand the quality of the fossil record of early tetrapods (Tetrapoda, minus Lissamphibia and Amniota) because of their key role in the transition of vertebrates from water to land, their dominance of terrestrial faunas for over 100 million years of the late Palaeozoic and earlyMesozoic, and their variable fates during the end−Permian mass extinction. The first description of an early tetrapod dates back to 1824, and since then discoveries have occurred at a rather irregular pace, with peaks and troughs corresponding to some of the vicissitudes of human history through the past two centuries. As expected, the record is dominated by the well−sampled sedimentary basins of Europe and North America, but finds from other continents are increasing rapidly. Comparisons of snapshots of knowledge in 1900, 1950, and 2000 show that discovery of new species has changed the shape of the species−level diversification curve, contrary to earlier studies of family−level taxa. There is, however, little evidence that taxon counts relate to research effort (as counted by numbers of publications), and there are no biasing effects associated with differential study of different time intervals through the late Palaeozoic and Mesozoic. In fact, levels of effort are apparently not related to geological time, with no evidence that workers have spent more time on more recent parts of the record. In particular, the end−Permian mass extinction was investigated to determine whether diversity changes through that interval might reflect worker effort: it turns out that most records of early tetrapod taxa (when corrected for duration of geological series) occur in the Lower Triassic