Development of an HIV-1-dependent expression vector with the Cre/loxP system.

Previously, we used the human methionine tRNA promoter as an expression cassette for hammerhead ribozymes. The tRNA promoter driven ribozyme was targeted against the LTR portion of the HIV-1 NL4-3 strain. We constructed VSV-G-pseudotyped MuLV-based vectors expressing the ribozyme. The ribozyme expressing retrovirus vector strongly suppressed gag p24 antigen production in freshly HIV-1 infected MT-4 cells. In this study, the potential of such a molecular genetic intervention was examined by using the Cre-loxP recombination system. Site-specific excision of HIV-1 was achieved by using this model system with an acute infection. These studies represent one step toward the development of a novel antiviral strategy for the treatment of AIDS.     

“My Heart Die in Me”: Idioms of Distress and the Development of a Screening Tool for Mental Suffering in Southeast Liberia

The integration of culturally salient idioms of distress into mental healthcare delivery is essential for effective screening, diagnosis, and treatment. This study systematically explored idioms, explanatory models, and conceptualizations in Maryland County, Liberia to develop a culturally-resonant screening tool for mental distress. We employed a sequential mixed-methods process of: (1) free-lists and semi-structured interviews (n?=?20); patient chart reviews (n?=?315); (2) pile-sort exercises, (n?=?31); and (3) confirmatory focus group discussions (FGDs); (n?=?3) from June to December 2017. Free-lists identified 64 idioms of distress, 36 of which were eliminated because they were poorly understood, stigmatizing, irrelevant, or redundant. The remaining 28 terms were used in pile-sort exercises to visualize the interrelatedness of idioms. Confirmatory FDGs occurred before and after the pile-sort exercise to explain findings. Four categories of idioms resulted, the most substantial of which included terms related to the heart and to the brain/mind. The final screening tool took into account 11 idioms and 6 physical symptoms extracted from patient chart reviews. This study provides the framework for culturally resonant mental healthcare by cataloguing language around mental distress and designing an emic screening tool for validation in a clinical setting.     

Evaluation of species boundaries in sympatric and parapatric populations of Mesoamerican toads

Approaches that integrate multiple independent, yet complimentary, lines of evidence have been effectively utilized to identify and evaluate species diversity. Integrative approaches are especially useful in taxa that exhibit cryptic diversity and are highly morphologically conserved, as well as organisms whose distributions may be sympatric or parapatric. The Incilius coccifer complex in Honduras is comprised of three putative taxa: I. coccifer, I. ibarrai and I. porteri. The taxonomy of the I. coccifer complex has been a source of debate among specialists, with some recognizing three species, while others choose to recognize one widespread taxon. To assess species boundaries and evaluate the taxonomic structure for the I. coccifer complex, we utilized a combination of comprehensive field sampling, molecular phylogenetics and macroecological modelling. Using 58 samples representing all three putative taxa, we generated sequence data from the mitochondrial loci 16S and COI in order to assess genetic diversity and phylogenetic relationships, and tested putative species boundaries using General Mixed Yule‐Coalescent models. To evaluate macroecological differences in the distribution of putative taxa, we utilized maximum entropy modelling and identified areas of suitable and non‐suitable habitat, as well as identifying potential areas of overlap between species habitats. We recovered three clades that broadly correspond to the three named taxa that, while being monophyletic, are separated by relatively small genetic distances. Species distribution models revealed that I. coccifer is macroecologically different than the other two taxa, but that I. ibarrai and I. porteri are highly similar. We uncovered cases of sympatry between pairs of species in at least three localities in Honduras, suggesting the potential for hybridization in these closely related lineages.     

Lamin B1 acetylation slows the G1 to S cell cycle transition through inhibition of DNA repair

The integrity and regulation of the nuclear lamina is essential for nuclear organization and chromatin stability, with its dysregulation being linked to laminopathy diseases and cancer. Although numerous posttranslational modifications have been identified on lamins, few have been ascribed a regulatory function. Here, we establish that lamin B1 (LMNB1) acetylation at K134 is a molecular toggle that controls nuclear periphery stability, cell cycle progression, and DNA repair. LMNB1 acetylation prevents lamina disruption during herpesvirus type 1 (HSV-1) infection, thereby inhibiting virus production. We also demonstrate the broad impact of this site on laminar processes in uninfected cells. LMNB1 acetylation negatively regulates canonical nonhomologous end joining by impairing the recruitment of 53BP1 to damaged DNA. This defect causes a delay in DNA damage resolution and a persistent activation of the G1/S checkpoint. Altogether, we reveal LMNB1 acetylation as a mechanism for controlling DNA repair pathway choice and stabilizing the nuclear periphery.     

Spatial distribution and effects of Lantana camara invasion on soil properties and native vegetation community composition in Tugwi-Mukosi Recreational Park,Masvingo, Zimbabwe

This study investigated spatial distribution and effects of Lantana camara invasion on soil properties and vegetation composition in Tugwi-Mukosi Recreational Park. Supervised classification with the Random Forest classifier was used to map L. camara in the park. The study area was stratified into two categories based on soil type and the extent of L. camara invasion. Stratified random sampling was used in data collection to assess differences in species diversity and soil properties in the park. Results revealed that L. camara covered an area of 1772 ha. Using Random Forest classification, the study obtained an accuracy score of 92.1% and an F1 score of 86.25%. Two-way ANOVA showed significant effect of L. camara invasion on soil moisture (F = 28.143, p = 0.000), organic matter (F = 13.377, p = 0.003), pH (F = 1272.369, p = 0.000), total nitrogen (F = 51.762, p = 0.000), total phosphorus (F = 5.000, p = 0.045), woody species density (F = 4.987, p = 0.027), basal area (F = 10.393, p = 0.001), grass species richness (F = 196.258, p = 0.000) and grass cover (F = 3.637, p = 0.042). These results suggest that L. camara was modifying the soil and vegetation properties of the ecosystem which has implications on biodiversity.