Evidence of recent interkingdom horizontal gene transfer between bacteria and Candida parapsilosis

<p>Abstract</p> <p>Background</p> <p>To date very few incidences of interdomain gene transfer into fungi have been identified. Here, we used the emerging genome sequences of <it>Candida albicans </it>WO-1, <it>Candida tropicalis, Candida parapsilosis, Clavispora lusitaniae, Pichia guilliermondii</it>, and <it>Lodderomyces elongisporus </it>to identify recent interdomain HGT events. We refer to these as CTG species because they translate the CTG codon as serine rather than leucine, and share a recent common ancestor.</p> <p>Results</p> <p>Phylogenetic and syntenic information infer that two <it>C. parapsilosis </it>genes originate from bacterial sources. One encodes a putative proline racemase (PR). Phylogenetic analysis also infers that there were independent transfers of bacterial PR enzymes into members of the Pezizomycotina, and protists. The second HGT gene in <it>C. parapsilosis </it>belongs to the phenazine F (PhzF) superfamily. Most CTG species also contain a fungal PhzF homolog. Our phylogeny suggests that the CTG homolog originated from an ancient HGT event, from a member of the proteobacteria. An analysis of synteny suggests that <it>C. parapsilosis </it>has lost the endogenous fungal form of PhzF, and subsequently reacquired it from a proteobacterial source. There is evidence that <it>Schizosaccharomyces pombe </it>and Basidiomycotina also obtained a PhzF homolog through HGT.</p> <p>Conclusion</p> <p>Our search revealed two instances of well-supported HGT from bacteria into the CTG clade, both specific to <it>C. parapsilosis</it>. Therefore, while recent interkingdom gene transfer has taken place in the CTG lineage, its occurrence is rare. However, our analysis will not detect ancient gene transfers, and we may have underestimated the global extent of HGT into CTG species.</p

Chromosomal G + C Content Evolution in Yeasts: Systematic Interspecies Differences, and GC-Poor Troughs at Centromeres

The G + C content at synonymous codon positions (GC3s) in genes varies along chromosomes in most eukaryotes. In Saccharomyces cerevisiae, regions of high GC3s are correlated with recombination hot spots, probably due to biased gene conversion. Here we examined how GC3s differs among groups of related yeast species in the Saccharomyces and Candida clades. The chromosomal locations of GC3s peaks and troughs are conserved among four Saccharomyces species, but we find that there have been highly consistent small shifts in their GC3s values. For instance, 84% of all S. cerevisiae genes have a lower GC3s value than their S. bayanus orthologs. There are extensive interspecies differences in the Candida clade both in the median value of GC3s (ranging from 22% to 49%) and in the variance of GC3s among genes. In three species—Candida lusitaniae, Pichia stipitis, and Yarrowia lipolytica—there is one region on each chromosome in which GC3s is markedly reduced. We propose that these GC-poor troughs indicate the positions of centromeres because in Y. lipolytica they coincide with the five experimentally identified centromeres. In P. stipitis, the troughs contain clusters of the retrotransposon Tps5. Likewise, in Debaryomyces hansenii, there is one cluster of the retrotransposon Tdh5 per chromosome, and all these clusters are located in GC-poor troughs. Locally reduced G + C content around centromeres is consistent with a model in which G + C content correlates with recombination rate, and recombination is suppressed around centromeres, although the troughs are unexpectedly wide (100–300 kb)

Spare-Parts Technique for Concurrent Treatment of Ectrodactyly of the Feet and Syndactyly of the Hands in a 2-Year-Old Boy: A Case Report

Syndactyly is the most frequently occurring congenital malformation of the limbs. Although common, few studies have reported treating syndactyly using Z-plasty with and without full-thickness grafting. We present a 2-year-old boy who presented to our clinic with ectrodactyly of the feet and simple complete syndactyly of two fingers on each hand. After ectrodactyly reconstruction, we used the excess foot skin to cover finger defects. The patient recovered well postoperatively, with matching skin and no trouble with hair growth. Use of a spare-parts technique can help avoid complications associated with harvesting grafts from other donor sites. The results reinforce the importance of coordinating reconstructive techniques when necessary for operative treatment of syndactyly of the hands

Suturing Workshop for Third-Year Medical Students: A Modern Educational Approach

Background: This study sought to determine if developing suturing workshops based on modern educational theory would lead to a significant increase in third-year medical students’ confidence and preparedness as compared to before the workshop. Methods: A group of pre-clinical, third-year medical students (n = 20) were voluntarily recruited. The workshop consisted of an interactive didactic session, a hands-on suturing session, and a question-answer session with surgeons. The nine-point Likert scale surveys were given pre-and post-workshop to 17 participants. Total scores of “confidence” and “preparedness” were analyzed using the Student t-test. Results of Q-Q plot and normality tests were used to validate the normality assumption. All analysis was conducted using SAS Software 9.4 (Cary, North Carolina). Results: A statistically significant increase in both confidence and preparedness was found between results of pre- and post-workshop surveys. Average total scores in confidence increased by 19.7 points, from 19.3 to 39 (95% CI: 15.0-24.4; P value \u3c 0.001). For scores in preparedness, the total score increased by an average of 18.4 points, from 22.8 to 41.2 (95% CI: 14.1-22.8; P value \u3c 0.001). Conclusions: These findings suggest that a structured course based on modern educational theory can increase both the confidence and preparedness of third-year medical students who are matriculating into their hospitalbased clerkships

Neuropsychological Assessment, Neuroimaging, and Neuropsychiatric Evaluation in Pediatric and Adult Patients with Sickle Cell Disease (SCD)

Traditionally, neuropsychological deficits due to Sickle Cell Disease (SCD) have been understudied in adults. We have begun to suspect, however, that symptomatic and asymptomatic Cerebrovascular Events (CVE) may account for an alarming number of deficits in this population. In the current brief review, we critically evaluated the pediatric and adult literatures on the neurocognitive effects of SCD. We highlighted the studies that have been published on this topic and posit that early detection of CVE via neurocognitive testing, neuropsychiatric evaluations, and neuroimaging may significantly reduce adult cognitive and functional morbidities

Evolution of pathogenicity and sexual reproduction in eight Candida genomes

Candida species are the most common cause of opportunistic fungal infection worldwide. Here we report the genome sequences of six Candida species and compare these and related pathogens and non-pathogens. There are significant expansions of cell wall, secreted and transporter gene families in pathogenic species, suggesting adaptations associated with virulence. Large genomic tracts are homozygous in three diploid species, possibly resulting from recent recombination events. Surprisingly, key components of the mating and meiosis pathways are missing from several species. These include major differences at the mating-type loci (MTL); Lodderomyces elongisporus lacks MTL, and components of the a1/2 cell identity determinant were lost in other species, raising questions about how mating and cell types are controlled. Analysis of the CUG leucine-to-serine genetic-code change reveals that 99% of ancestral CUG codons were erased and new ones arose elsewhere. Lastly, we revise the Candida albicans gene catalogue, identifying many new genes.publishe

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder