Developmental Maturation within the Hematopoietic System

Stem cell biologists creating cells and tissues for therapies, disease modeling, and drug screening have observed that differentiating pluripotent stem cells (PSCs) tend to produce cells at an embryonic stage of development but have difficulty maturing into adult definitive cells. A better understanding of developmental maturation will provide insights into embryogenesis and permit more accurate disease modeling. In the hematopoietic system, primitive and definitive cells are distinguished by functional transplantation assays, well characterized cell surface antigens, and gene expression signatures. We examined the transition in vivo in transplanted murine hematopoietic stem cells (HSCs) and in vitro in human PSC (hPSC) derived red blood cells (RBCs). We found that the hematopoietic microenvironment of the recipient significantly affects the outcome of HSC transplantation. The earliest embryonic HSCs perform better in neonatal recipients, whereas more mature adult-like HSCs perform better in adult recipients. The preference may be related to different active hematopoietic niches in neonates and adults, as we observed adult HSCs homing to different tissues in neonatal and adult recipients. Additionally, we found that proliferation may enhance the neonatal engraftment potential of adult-like HSCs. Our data highlight the importance of the host environment on transplantation outcomes, and point to the neonatal transplant model as a tool to functionally examine the earliest HSCs and primitive derivatives of PSCs

Levamisole-induced leukocytoclastic vasculitis and neutropenia in a patient with cocaine use: An extensive case with necrosis of skin, soft tissue, and cartilage

Abstract Levamisole-induced vasculitis is a relatively new entity in people who use cocaine. We describe a 44-year-old woman with a history of cocaine use who presented with a complaint of a painful rash of 2-3 month’s duration on her extremities, cheeks, nose, and earlobes. She had not experienced fever, weight loss, alopecia, dry eyes, oral ulcers, photosensitivity, or arthralgia. Examination revealed tender purpuric eruptions with central necrosis on her nose, cheeks, earlobes, and extremities. Laboratory investigations revealed neutropenia, an elevated erythrocyte sedimentation rate (ESR), presence of lupus anticoagulant, low complement component 3 (C3), and presence of perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA). A urine toxicology screen was positive for cocaine, and gas chromatography–mass spectrometry was positive for levamisole. Skin biopsy showed leukocytoclastic vasculitis and small vessel thrombosis. Necrotic lesions of the nose led to its self-amputation. Large bullae on the lower extremities ruptured, leading to wound infection and extensive necrosis that required multiple surgical debridements. When necrosis progressed despite debridement, bilateral above-knee amputation of the legs was performed. Once new lesions stopped appearing, the patient was discharged home. Two months later, she had a recurrence related to cocaine use. To the best of our knowledge, this is only the second reported case of levamisole-induced vasculitis that required above-knee amputation

A multiplex-system to target 16 male-specific and 15 autosomal genetic markers for orang-utans (genus: Pongo )

Genetic studies of dispersal on local spatial and short temporal scales require a large number of autosomal microsatellites. However, the study of dispersal over large spatial scales and the resolution of deep evolutionary histories require marker systems that are preferentially inherited through the male or female line. Addressing such questions in endangered orang-utans (genus: Pongo) bears significant relevance to species conservation, as habitat destruction and fragmentation pose a significant threat to the whole genus. Here, we report 16 male-specific markers (nine human-derived microsatellites, six single nucleotide and one insertion-deletion polymorphisms), and 15 novel Pongo-derived autosomal microsatellite loci. All 31 markers can be amplified in four multiplex polymerase chain reactions even in DNA derived from faecal material. The markers can be applied to studying a wide range of important questions in this genus, such as conservation genetics, social structure, phylogeny and phylogeograph

Modification of a bi-functional diguanylate cyclase-phosphodiesterase to efficiently produce cyclic diguanylate monophosphate

AbstractCyclic-diGMP is a bacterial messenger that regulates many physiological processes, including many attributed to pathogenicity. Bacteria synthesize cyclic-diGMP from GTP using diguanylate cyclases; its hydrolysis is catalyzed by phosphodiesterases. Here we report the over-expression and purification of a bi-functional diguanylate cyclase-phosphodiesterase from Agrobacterium vitis S4. Using homology modeling and primary structure alignment, we identify several amino acids predicted to participate in the phosphodiesterase reaction. Upon altering selected residues, we obtain variants of the enzyme that efficiently and quantitatively catalyze the synthesis of cyclic-diGMP from GTP without hydrolysis to pGpG. Additionally, we identify a variant that produces cyclic-diGMP while immobilized to NiNTA beads and can catalyze the conversion of [α-32P]-GTP to [32P]-cyclic-diGMP. In short, we characterize a novel cyclic-diGMP processing enzyme and demonstrate its utility for efficient and cost-effective production of cyclic-diGMP, as well as modified cyclic-diGMP molecules, for use as probes in studying the many important biological processes mediated by cyclic-diGMP

Assessing time dependent changes in microbial composition of biological crime scene traces using microbial RNA markers

Current body fluid identification methods do not reveal any information about the time since deposition (TsD) of biological traces, even though determining the age of traces could be crucial for the investigative process. To determine the utility of microbial RNA markers for TsD estimation, we examined RNA sequencing data from five forensically relevant body fluids (blood, menstrual blood, saliva, semen, and vaginal secretion) over seven time points, ranging from fresh to 1.5 years. One set of samples was stored indoors while another was exposed to outdoor conditions. In outdoor samples, we observed a consistent compositional shift, occurring after 4 weeks: this shift was characterized by an overall increase in non-human eukaryotic RNA and an overall decrease in prokaryotic RNA. In depth analyses showed a high fraction of tree, grass and fungal signatures, which are characteristic for the environment the samples were exposed to. When examining the prokaryotic fraction in more detail, three bacterial phyla were found to exhibit the largest changes in abundance, namely Actinobacteria, Proteobacteria and Firmicutes. More detailed analyses at the order level were done using a Lasso regression analysis to find a predictive subset of bacterial taxa. We found 26 bacterial orders to be indicative of sample age. Indoor samples did not reveal such a clear compositional change at the domain level: eukaryotic and prokaryotic abundance remained relatively stable across the assessed time period. Nonetheless, a Lasso regression analysis identified 32 bacterial orders exhibiting clear changes over time, enabling the prediction of TsD. For both indoor and outdoor samples, a larger number (around 60%) of the bacterial orders identified as indicative of TsD are part of the Actinobacteria, Proteobacteria and Firmicutes. In summary, we found that the observed changes across time are not primarily due to changes associated with body fluid specific bacteria but mostly due to accumulation of bacteria from the environment. Orders of these environmental bacteria could be evaluated for TsD prediction, considering the location and environment of the crime scene. However, further studies are needed to verify these findings, determine the applicability across samples, replicates, donors, and other variables, and also to further assess the effect of different seasons and locations on the samples

Comparative evaluation of the MAPlex, Precision ID Ancestry Panel, and VISAGE Basic Tool for biogeographical ancestry inference

Biogeographical ancestry (BGA) inference from ancestry-informative markers (AIMs) has strong potential to support forensic investigations. Over the past two decades, several forensic panels composed of AIMs have been developed to predict ancestry at a continental scale. These panels typically comprise fewer than 200 AIMs and have been designed and tested with a limited set of populations. How well these panels recover patterns of genetic diversity relative to larger sets of markers, and how accurately they infer ancestry of individuals and populations not included in their design remains poorly understood. The lack of comparative studies addressing these aspects makes the selection of appropriate panels for forensic laboratories difficult. In this study, the model-based genetic clustering tool STRUCTURE was used to compare three popular forensic BGA panels: MAPlex, Precision ID Ancestry Panel (PIDAP), and VISAGE Basic Tool (VISAGE BT) relative to a genome-wide reference set of 10k SNPs. The genotypes for all these markers were obtained for a comprehensive set of 3957 individuals from 228 worldwide human populations. Our results indicate that at the broad continental scale (K = 6) typically examined in forensic studies, all forensic panels produced similar genetic structure patterns compared to the reference set (G′ ≈ 90%) and had high classification performance across all regions (average AUC-PR > 97%). However, at K = 7 and K = 8, the forensic panels displayed some region-specific clustering deviations from the reference set, particularly in Europe and the region of East and South-East Asia, which may be attributed to differences in the design of the respective panels. Overall, the panel with the most consistent performance in all regions was VISAGE BT with an average weighted AUC̅W score of 96.26% across the three scales of geographical resolution investigated

Female philopatry and its social benefits among Bornean orangutans

Female philopatry in mammals is generally associated with ecological and sometimes social benefits, and often with dispersal by males. Previous studies on dispersal patterns of orangutans, largely non-gregarious Asian great apes, have yielded conflicting results. Based on 7years of observational data and mitochondrial and nuclear DNA analyses on fecal samples of 41 adult Bornean orangutans (Pongo pygmaeus wurmbii) from the Tuanan population, we provide both genetic and behavioral evidence for male dispersal and female philopatry. Although maternally related adult female dyads showed similar home-range overlap as unrelated dyads, females spent much more time in association with known maternal relatives than with other females. While in association, offspring of maternally related females frequently engaged in social play, whereas mothers actively prevented this during encounters with unrelated mothers, suggesting that unrelated females may pose a threat to infants. Having trustworthy neighbors may therefore be a social benefit of philopatry that may be common among solitary mammals, thus reinforcing female philopatric tendencies in such species. The results also illustrate the diversity in dispersal patterns found within the great-ape lineag

Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations

©2016. American Geophysical Union. Geomagnetically aligned density structures with a range of sizes exist in the near-Earth plasma environment, including 10-100 km wide VLF/HF wave-ducting structures. Their small diameters and modest density enhancements make them difficult to observe, and there is limited evidence for any of the several formation mechanisms proposed to date. We present a case study of an event on 26 August 2014 where a travelling ionospheric disturbance (TID) shortly precedes the formation of a complex collection of field-aligned ducts, using data obtained by the Murchison Widefield Array (MWA) radio telescope. Their spatiotemporal proximity leads us to suggest a causal interpretation. Geomagnetic conditions were quiet at the time, and no obvious triggers were noted. Growth of the structures proceeds rapidly, within 0.5 h of the passage of the TID, attaining their peak prominence 1-2 h later and persisting for several more hours until observations ended at local dawn. Analyses of the next 2 days show field-aligned structures to be preferentially detectable under quiet rather than active geomagnetic conditions. We used a raster scanning strategy facilitated by the speed of electronic beamforming to expand the quasi-instantaneous field of view of the MWA by a factor of 3. These observations represent the broadest angular coverage of the ionosphere by a radio telescope to date