Meiosis in the human pathogen Aspergillus fumigatus has the highest known number of crossovers

Evidence from both population genetics and a laboratory sexual cycle indicate that sex is common in the fungus Aspergillus fumigatus. However, the impact of sexual reproduction has remained unclear. Here, we show that meiosis in A. fumigatus involves the highest known recombination rate, producing ~29 crossovers per chromosome. This represents the highest known crossover rate for any Eukaryotic species. We validate this recombination rate by mapping resistance to acriflavine, a common genetic marker. We further show that this recombination rate can produce the commonly encountered TR34/L98H azole-resistant cyp51A haplotype in each sexual event, facilitating its rapid and global spread. Understanding the consequences of this unparalleled crossover rate will not only enrich our genetic understanding of this emergent human pathogen, but of meiosis in general.

A Low-Crossover and Fast-Kinetics Thiolate Negolyte for Aqueous Redox Flow Batteries

Aqueous redox flow batteries (ARFBs) are a promising technology for large-scale energy storage. Developing high-capacity and long-cycle negolyte materials is one of major challenges for practical ARFBs. Inorganic polysulfide is promising for ARFBs owing to its low cost and high solubility. However, it suffers from severe crossover resulting in low coulombic efficiency and limited lifespan. Organosulfides are more resistant to crossover than polysulfides owing to their bulky structures, but they suffer from slow reaction kinetics. Herein, we report a thiolate negolyte prepared by an exchange reaction between a polysulfide and an organosulfide, preserving low crossover rate of the organosulfide and high reaction kinetics of the polysulfide. The thiolate denoted as 2-hydroxyethyl disulfide+potassium polysulfide (HEDS+K2S2) shows reduced crossover rate than K2S2, faster reaction kinetics than HEDS, and longer lifespan than both HEDS and K2S2. The 1.5 M HEDS+1.5 M K2S2 static cell demonstrated 96 Ah L-1negolyte over 100 and 200 cycles with a high coulombic efficiency of 99.2% and 99.6% at 15 and 25 mA cm-2, respectively. The 0.5 M HEDS+0.5 M K2S2 flow cell delivered a stable and high capacity of 30.7 Ah L-1negolyte over 400 cycles (691 h) at 20 mA cm-2. This study presents an effective strategy to enable low-crossover and fast-kinetics sulfur-based negolytes for advanced ARFBs.

Final overall survival for the phase III KN177 study: Pembrolizumab versus chemotherapy in microsatellite instability-high/mismatch repair deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC).

3500 Background: In the phase III, randomized open-label KEYNOTE-177 (NCT02563002) study 1L pembrolizumab (pembro) versus chemotherapy (chemo) provided superior progression-free survival (PFS) at second interim analysis (IA2) in patients (pts) with MSI-H/dMMR mCRC. The study continued to final analysis of overall survival (OS), planned after 190 OS events or 12 months after IA2, whichever occurred first. We present results of the final analysis of OS, 12 months after IA2. Methods: A total of 307 pts with MSI-H/dMMR mCRC and ECOG PS 0 or 1 were randomized 1:1 to 1L pembro 200 mg Q3W for up to 2y or investigator’s choice of mFOLFOX6 or FOLFIRI Q2W ± bevacizumab or cetuximab. Treatment continued until PD, unacceptable toxicity, pt/investigator decision to withdraw, or completion of 35 cycles (pembro only). Pts receiving chemo could crossover to pembro for up to 35 cycles after confirmed PD. Primary end points were OS and PFS (RECIST v1.1, central review). Secondary end points included ORR, duration of response (DOR) (RECIST v1.1, central review), and safety. For OS significance, the p-value had to meet a prespecified α of 0.0246 (one-sided). Sensitivity analyses to adjust for crossover effect were performed. Data cut-off for final analysis was Feb 19, 2021. Results: Median (range) study follow-up was 44.5 mo (36.0-60.3) with pembro vs 44.4 mo (36.2-58.6) with chemo. 56 (36%) pts crossed over from chemo to pembro, with 37 more receiving anti-PD-1/PD-L1 therapies off study (60% effective crossover rate in the ITT). The HR for OS favored pembro vs chemo with a trend toward reduction in the risk of death (HR 0.74; 95% CI, 0.53-1.03; P=0.0359; median not reached [NR] vs 36.7 mo); this difference did not reach statistical significance. Sensitivity analysis by the rank-preserving structure failure time model and inverse probability of censoring weighting showed OS HRs of 0.66 (95% CI 0.42-1.04) and 0.77 (95% CI 0.44-1.38), respectively. Pembro vs chemo met the prespecified criteria for PFS superiority at IA2. At final analysis, median PFS was 16.5 mo vs 8.2 mo (HR 0.59; 95% CI, 0.45-0.79), but was not formally tested per analysis plan. Confirmed ORR was 45.1% (20 CR, 49 PR) vs 33.1% (6 CR, 45 PR). Median (range) DOR was NR (2.3+ to 53.5+) vs 10.6 mo (2.8 to 48.3+), respectively. Treatment-related adverse events (TRAEs) occurred in 79.7% vs 98.6% of pts; 21.6% vs 66.4%, respectively, had grade ≥3 TRAEs. Conclusions: As 1L therapy for pts with MSI-H/dMMR mCRC, pembro vs chemo provides statistically superior PFS with fewer TRAEs, and is associated with a trend toward reduced mortality that did not meet statistical significance likely due to the high crossover rate from chemo to anti-PD1/PD-L1 therapies. Together these data confirm pembro as a new standard-of-care in the 1L for pts with MSI-H/dMMR mCRC. Clinical trial information: NCT02563002.

Rat PRDM9 shapes recombination landscapes, duration of meiosis, gametogenesis, and age of fertility

BackgroundVertebrate meiotic recombination events are concentrated in regions (hotspots) that display open chromatin marks, such as trimethylation of lysines 4 and 36 of histone 3 (H3K4me3 and H3K36me3). Mouse and human PRDM9 proteins catalyze H3K4me3 and H3K36me3 and determine hotspot positions, whereas other vertebrates lacking PRDM9 recombine in regions with chromatin already opened for another function, such as gene promoters. While these other vertebrate species lacking PRDM9 remain fertile, inactivation of the mousePrdm9gene, which shifts the hotspots to the functional regions (including promoters), typically causes gross fertility reduction; and the reasons for these species differences are not clear.ResultsWe introducedPrdm9deletions into theRattus norvegicusgenome and generated the first rat genome-wide maps of recombination-initiating double-strand break hotspots. Rat strains carrying the same wild-typePrdm9allele shared 88% hotspots but strains with differentPrdm9alleles only 3%. AfterPrdm9deletion, rat hotspots relocated to functional regions, about 40% to positions corresponding toPrdm9-independent mouse hotspots, including promoters. Despite the hotspot relocation and decreased fertility,Prdm9-deficient rats of the SHR/OlaIpcv strain produced healthy offspring. The percentage of normal pachytene spermatocytes in SHR-Prdm9mutants was almost double than in the PWD male mouse oligospermic sterile mutants. We previously found a correlation between the crossover rate and sperm presence in mousePrdm9mutants. The crossover rate of SHR is more similar to sperm-carrying mutant mice, but it did not fully explain the fertility of the SHR mutants. Besides mild meiotic arrests at rat tubular stages IV (mid-pachytene) and XIV (metaphase), we also detected postmeiotic apoptosis of round spermatids. We found delayed meiosis and age-dependent fertility in both sexes of the SHR mutants.ConclusionsWe hypothesize that the relative increased fertility of rat versus mousePrdm9mutants could be ascribed to extended duration of meiotic prophase I. While rat PRDM9 shapes meiotic recombination landscapes, it is unnecessary for recombination. We suggest that PRDM9 has additional roles in spermatogenesis and speciation—spermatid development and reproductive age—that may help to explain male-specific hybrid sterility.

The effective population size modulates the strength of GC biased gene conversion in two passerines

Understanding the determinants of genomic base composition is fundamental to understanding genome evolution. GC biased gene conversion (gBGC) is a key driving force behind genomic GC content, through the preferential incorporation of GC alleles over AT alleles during recombination, driving them towards fixation. The majority of work on gBGC has focussed on its role in coding regions, largely to address how it confounds estimates of selection. Non-coding regions have received less attention, particularly in regard to the interaction of gBGC and the effective population size (Ne) within and between species. To address this, we investigate how the strength of gBGC (B = 4Neb, where b is the conversion bias) varies within the non-coding genome of two wild passerines. We use a dataset of published high coverage genomes (10 great tits and 10 zebra finches) to estimate B, nucleotide diversity, changes in Ne, and crossover rates from linkage maps, in 1Mb homologous windows in each species. We demonstrate remarkable conservation of both B and crossover rate between species. We show that the mean strength of gBGC in the zebra finch is more than double that in the great tit, consistent with its twofold greater effective population size. B also correlates with both crossover rate and nucleotide diversity in each species. Finally, we estimate equilibrium GC content from both divergence and polymorphism data, which indicates that B has been increasing in both species, and provide support for population expansion explaining a large proportion of this increase in the zebra finch.

Distal transradial access for coronary angiography and interventions in everyday practice: data from the TRIANGLE Registry

Background Transradial access has become the primary route for coronary angiography (CAG) and percutaneous coronary interventions (PCI). Recently a new puncture site more distally on the dorsal side of the hand in the area of the anatomical snuffbox has been developed. Purpose With this multicenter registry, we wish to demonstrate the feasibility and safety of the distal transradial access (dTRA) and assess the rate of radial artery occlusion (RAO). As an exploratory endpoint, we compared peri-interventional data between right- and left-radial access and differences between the true anatomical snuffbox (SB) and the distal- dorsal (DD) puncture site. Methods Between December 2018 and May 2019 we included all patients into this registry with a planned CAG or PCI via dTRA in three cardiology centers in Germany. Procedural data, puncture success, crossover rate and complications were registered. We examined proximal and distal radial artery patency by ultrasound within 48 h after removal of compression device. Results A total of 327 patients were enrolled (mean age: 69 years, male: 69%), in 5 cases bilateral distal puncture was performed, puncture success was high (N=316/332, 95%) and the crossover rate was low (27/332, 8%). The rate of proximal (2/332) and distal (3/332) RAO was low. Major complications were not encountered. The comparison between SB and DD site and left- and right radial access showed no significant differences (see table). The indication for CAG in 50% of the population was acute coronary syndrome, including 28 patients with ST elevation myocardial infarction (8.4%). Overall PCI rate was 48%. PCI cases did not demonstrate a crossover rate higher than in CAG. PCI on chronic total occlusion (CTO) was performed in 16 cases including bilateral dTRA. Conclusion Coronary angiography and interventions via dTRA can be performed with a high rate of success and safety. This data suggests a reduced rate of RAO compared to previous reported data after cannulation via the standard forearm radial artery puncture site. Randomized studies are needed to further investigate these results. Funding Acknowledgement Type of funding source: None

IMPLEMENTASI ALGORITMA GENETIKA DALAM ELIMINASI BENTROKAN JADWAL PERKULIAHAN DI POLITEKNIK UNISMA MALANG

Penelitian ini bertujuan memperoleh efisiensi penyusunan jadwal dengan mengeliminasi bentrokan jadwal menggunakan metode algoritma genetika. Metode penelitian diawali dengan pengumpulan data awal dimana ditemukan permasalaham bentrokan ruang, bentrokan kelas dan bentrokan dosen. Permasalahan tersebut digunakan sebagai dasar perumusan nilai fitness. Nilai fitness dalam penelitian ini deitentukan 1 / (1 + BD + BK + BR). Algoritma genetika penelitian ini menggunakan 6 kromosom agar mendapatkan solusi optimal. Nilai crossover rate di atur sebesar 80%, serta mutation rate dikontrol pada nilai 0.3 atau 30% agar pemrosesan tidak berlangsung lama. Hasil penelitian ini berupa aplikasi penyusunan jadwal berbasis android yang menerapkan algoritma genetika. Berdasarkan uji coba aplikasi menunjukkan bahwa hasil penjadwalan dengan algoritma genetika mampu mengeliminasi bentrokan jadwal. Kata kunci - Genetika, Fitness, Jadwal

Distal Radial Artery Access for Superficial Femoral Artery Interventions

Purpose: To compare the acute success and complication rates of distal radial (DR) vs proximal radial (PR) artery access for superficial femoral artery (SFA) interventions. Materials and Methods: Between 2016 and 2019, 195 consecutive patients with symptomatic SFA stenosis were treated via DR (n=38) or PR (n=157) access using a sheathless guide. Secondary access was achieved through the pedal artery when necessary. The main outcomes were technical success, major adverse events (MAEs), and access site complications. Secondary outcomes were treatment success, fluoroscopy time, radiation dose, procedure time, and crossover rate to another puncture site. Results: Overall technical success was achieved in 188 patients (96.4%): 37 of 38 patients (97.3%) in the DR group and 151 of 157 patients (96.2%) in the PR group (p=0.9). Dual (transradial and transpedal) access was used in 14 patients (36.8%) in the DR group and 28 patients (18.9%) in the PR group (p<0.01). Chronic total occlusions were recanalized in 25 of 26 DR patients (96.1%) and in 79 of 81 PR patients (92.6%) (p=0.57). The crossover rate to femoral access was 0% in the DR group vs 3.2% in the PR group (p=0.59). Stents were implanted in the SFA in 15 DR patients (39.4%) and in 39 patients (24.8%) in the PR group (p=0.1). The contrast volume, fluoroscopy time, radiation dose, and procedure time were not statistically different between the DR and PR groups, nor were the rates of access site complications (2.6% and 7.0%, respectively). The cumulative incidences of MAE at 6 months in the DR and PR groups were 15.7% vs 14.6%, respectively (p=0.8). Conclusion: SFA interventions can be safely and effectively performed using PR or DR access with acceptable morbidity and a high technical success rate. DR access is associated with few access site complications.

Genetic Algorithm for Teaching Distribution based on Lecturers’ Expertise

The teaching distribution for lecturers based on their expertise is very important in the teaching and learning process. Lecturers who teach a course that is in accordance with their interests and abilities will make it easier for them to deliver material in class. In addition, students will also be easier to accept the material presented. However, in reality, the teaching distribution is often not in accordance with the expertise of the lecturer so that the lecturers are not optimal in providing material to their students. This problem can be solved using optimization methods such as the genetic algorithm. This study offers a solution for teaching distribution that focuses on the interest of each lecturer by considering the order of priorities. The optimal parameters of the test results are crossover rate (cr) = 0.6, mutation rate (mr) = 0.4, number of generations = 40, and population size = 15. Genetic algorithm is proven to be able to produce teaching distribution solutions with a relatively high fitness value at 4903.3.