Directed conservation of the world's reef sharks and rays

Many shark populations are in decline around the world, with severe ecological and economic consequences. Fisheries management and marine protected areas (MPAs) have both been heralded as solutions. However, the effectiveness of MPAs alone is questionable, particularly for globally threatened sharks and rays ('elasmobranchs'), with little known about how fisheries management and MPAs interact to conserve these species. Here we use a dedicated global survey of coral reef elasmobranchs to assess 66 fully protected areas embedded within a range of fisheries management regimes across 36 countries. We show that conservation benefits were primarily for reef-associated sharks, which were twice as abundant in fully protected areas compared with areas open to fishing. Conservation benefits were greatest in large protected areas that incorporate distinct reefs. However, the same benefits were not evident for rays or wide-ranging sharks that are both economically and ecologically important while also threatened with extinction. We show that conservation benefits from fully protected areas are close to doubled when embedded within areas of effective fisheries management, highlighting the importance of a mixed management approach of both effective fisheries management and well-designed fully protected areas to conserve tropical elasmobranch assemblages globally.

Processing of stalled replication forks in Bacillus subtilis

Accurate DNA replication and transcription elongation are crucial for preventing the accumulation of unreplicated DNA and genomic instability. Cells have evolved multiple mechanisms to deal with impaired replication fork progression, challenged by both intrinsic and extrinsic impediments. The bacterium Bacillus subtilis, which adopts multiple forms of differentiation and development, serves as an excellent model system for studying the pathways required to cope with replication stress to preserve genomic stability. This review focuses on the genetics, single molecule choreography, and biochemical properties of the proteins that act to circumvent the replicative arrest allowing the resumption of DNA synthesis. The RecA recombinase, its mediators (RecO, RecR, and RadA/Sms) and modulators (RecF, RecX, RarA, RecU, RecD2, and PcrA), repair licensing (DisA), fork remodelers (RuvAB, RecG, RecD2, RadA/Sms, and PriA), Holliday junction resolvase (RecU), nucleases (RnhC and DinG), and translesion synthesis DNA polymerases (PolY1 and PolY2) are key functions required to overcome a replication stress, provided that the fork does not collapse.

A New Cycler for Automated Peritoneal Dialysis to Provide Efficient Dialysis and Improved Sleep Quality

INTRODUCTION

Automated peritoneal dialysis (APD) employs cyclers to control inflow and outflow of the dialysis fluid to the patient's abdomen. To allow more patients to use this modality, cyclers should support the achievement of an adequate dialysis dose and be easy to use, cost-effective, and silent. The new SILENCIA cycler (Fresenius Medical Care, Bad Homburg, Germany), designed to improve these characteristics in comparison to its predecessor device, was evaluated in this respect in a prospective study.

METHODS

This cross-over study comprised two 2-week study periods, separated by a 3-week training phase. First, patients underwent APD with their current cycler (PD-NIGHT [Fresenius Medical Care, Bad Homburg, Germany] or HomeChoice Pro [Baxter, Deerfield, IL, USA] as control), followed by training on the SILENCIA cycler. Then, patients were switched to the SILENCIA cycler. During each treatment period, we collected data on total Kt/Vurea, ultrafiltration (UF) volume, patient-reported outcomes (sleep quality, among others), and device handling.

RESULTS

Sixteen patients were enrolled; 2 patients terminated the study prematurely before study intervention, 1 patient due to a protocol violation. In 13 patients, total Kt/Vurea and UF could be evaluated. Neither Kt/Vurea nor UF differed significantly between control and SILENCIA cyclers. Out of 10 patients answering the questionnaire on sleep quality after the 2-week phase with the SILENCIA cycler, sleep quality improved in 5 patients; in the other patients, sleep quality was rated unchanged compared to the previously used cycler. The average reported sleep time was 5.9 ± 1.8 h with the PD-NIGHT, 7.2 ± 2.1 h with HomeChoice Pro, and 8.0 ± 1.6 h with the SILENCIA cycler. All patients were much or very much satisfied with the new cycler.

CONCLUSION

The SILENCIA cycler delivers adequate urea clearance and UF. Importantly, sleep quality improved, possibly related to less caution messages and alarms.

Widespread diversity deficits of coral reef sharks and rays

A global survey of coral reefs reveals that overfishing is driving resident shark species toward extinction, causing diversity deficits in reef elasmobranch (shark and ray) assemblages. Our species-level analysis revealed global declines of 60 to 73% for five common resident reef shark species and that individual shark species were not detected at 34 to 47% of surveyed reefs. As reefs become more shark-depleted, rays begin to dominate assemblages. Shark-dominated assemblages persist in wealthy nations with strong governance and in highly protected areas, whereas poverty, weak governance, and a lack of shark management are associated with depauperate assemblages mainly composed of rays. Without action to address these diversity deficits, loss of ecological function and ecosystem services will increasingly affect human communities.

Integrating EM and Patch-seq data: Synaptic connectivity and target specificity of predicted Sst transcriptomic types

Neural circuit function is shaped both by the cell types that comprise the circuit and the connections between those cell types ¹ . Neural cell types have previously been defined by morphology ^{2, 3} , electrophysiology ^{4, 5} , transcriptomic expression ^6-8 , connectivity ^9-13 , or even a combination of such modalities ^14-16 . More recently, the Patch-seq technique has enabled the characterization of morphology (M), electrophysiology (E), and transcriptomic (T) properties from individual cells ^17-20 . Using this technique, these properties were integrated to define 28, inhibitory multimodal, MET-types in mouse primary visual cortex ²¹ . It is unknown how these MET-types connect within the broader cortical circuitry however. Here we show that we can predict the MET-type identity of inhibitory cells within a large-scale electron microscopy (EM) dataset and these MET-types have distinct ultrastructural features and synapse connectivity patterns. We found that EM Martinotti cells, a well defined morphological cell type ^{22, 23} known to be Somatostatin positive (Sst+) ^{24, 25} , were successfully predicted to belong to Sst+ MET-types. Each identified MET-type had distinct axon myelination patterns and synapsed onto specific excitatory targets. Our results demonstrate that morphological features can be used to link cell type identities across imaging modalities, which enables further comparison of connectivity in relation to transcriptomic or electrophysiological properties. Furthermore, our results show that MET-types have distinct connectivity patterns, supporting the use of MET-types and connectivity to meaningfully define cell types.

Bacillus subtilis RadA/Sms-Mediated Nascent Lagging-Strand Unwinding at Stalled or Reversed Forks Is a Two-Step Process: RadA/Sms Assists RecA Nucleation, and RecA Loads RadA/Sms

Replication fork rescue requires Bacillus subtilis RecA, its negative (SsbA) and positive (RecO) mediators, and fork-processing (RadA/Sms). To understand how they work to promote fork remodeling, reconstituted branched replication intermediates were used. We show that RadA/Sms (or its variant, RadA/Sms C13A) binds to the 5'-tail of a reversed fork with longer nascent lagging-strand and unwinds it in the 5'→3' direction, but RecA and its mediators limit unwinding. RadA/Sms cannot unwind a reversed fork with a longer nascent leading-strand, or a gapped stalled fork, but RecA interacts with and activates unwinding. Here, the molecular mechanism by which RadA/Sms, in concert with RecA, in a two-step reaction, unwinds the nascent lagging-strand of reversed or stalled forks is unveiled. First, RadA/Sms, as a mediator, contributes to SsbA displacement from the forks and nucleates RecA onto single-stranded DNA. Then, RecA, as a loader, interacts with and recruits RadA/Sms onto the nascent lagging strand of these DNA substrates to unwind them. Within this process, RecA limits RadA/Sms self-assembly to control fork processing, and RadA/Sms prevents RecA from provoking unnecessary recombination.

Applying Deep Learning Cancer Subtyping Algorithms Trained on Physical Slides to Multiphoton Imaging of Unembedded Samples

Introduction/Objective

Deep learning algorithms on digital images of physical tissue slides have shown potential improvements in accuracy and precision of diagnostic interpretation of neoplastic histology. Clustering-constrained- attention multiple-instance learning (CLAM) is one such method that identifies diagnostic sub-regions to accurately classify whole slides. Often, algorithm performance degrades when deployed on datasets that differ from the original set and it is subject to physical slide preparation variability. New multiphoton imaging modalities have potential workflow and quality advantages over physical slides, producing images analogous to whole slide imaging (WSI) without cutting artifacts, but performance of existing algorithms trained on digitized physical slides and applied to multiphoton images remains completely unknown. Given this, we aimed to test the performance of CLAM algorithms for subtyping renal cell carcinoma (RCC) and lung cancer (LC) applied to pseudo-colored multiphoton WSI.

Methods/Case Report

Clinical RCC and LC surgical resection samples were processed and imaged by Clearing Histology with MulitPhoton microscopy (CHiMP, Applikate Technologies, Fairfield, CT), producing digital images of un- cut, un-embeded tissue to generate H&E-like optical slices. Multiphoton images were downscaled to 0.5 um/px to match algorithm target resolution. CLAM models for subtyping RCC (chromophobe, clear cell, papillary) and LC (squamous & adenocarcinoma) previously trained using TCGA and CPTAC whole slide images of physical slides were applied directly to CHiMP multiphoton images without adjustment. Reference cancer subtype classifications were provided from physical and digital slides.

Results (if a Case Study enter NA)

For the subtypes included during training, multiphoton WSIs of RCC and LC were accurately subtyped by the CLAM models without stain normalization nor network fine tuning producing high prediction levels. Subtypes not included during the training (namely oncocytoma for RCC) resulted in low scoring model predictions (below 0.85), indicating specificity of identification. Multiple slide levels improved interpretation of several difficult cases for CLAM predictions.

Conclusion

This preliminary data suggests that CLAM models trained on standard H&E WSIs for RCC and LC subtyping are applicable to pseudo-H&E multiphoton WSIs without domain adaptations. This implies that diagnostic histologic features have been learned by these CLAM models and are efficiently recognized in digital histology images produced via CHiMP.

Clinical efficacy of SARS-CoV-2 vaccination in hemodialysis patients

Introduction

The COVID-19 pandemic is a global public health problem. Patients with end-stage renal disease on hemodialysis are at a higher risk of infection and mortality than the general population. Worldwide, a vaccination campaign has been developed that has been shown to reduce severe infections and deaths in the general population. However, there are currently limited data on the clinical efficacy of vaccinations in the hemodialysis population.

Methods

A national multicenter observational cohort was performed in Chile to evaluate the clinical efficacy of anti-SARS-CoV-2 vaccination in end-stage renal disease patients on chronic hemodialysis from February 2021 to August 2021. In addition, the BNT162b2 (Pfizer-BioNTech) and CoronaVac (Sinovac) vaccines were evaluated. The efficacy of vaccination in preventing SARS-CoV-2 infection, hospitalizations, and deaths associated with COVID-19 was determined.

Results

A total of 12,301 patients were evaluated; 10,615 (86.3%) received a complete vaccination (2 doses), 490 (4.0%) received incomplete vaccination, and 1196 (9.7%) were not vaccinated. During follow-up, 1362 (11.0%) patients developed COVID-19, and 150 died (case fatality rate: 11.0%). The efficacy of the complete vaccination in preventing infection was 18.1% (95% confidence interval [CI]:11.8–23.8%), and prevention of death was 66.0% (95% CI:60.6–70.7%). When comparing both vaccines, BNT162b2 and CoronaVac were effective in reducing infection and deaths associated with COVID-19. Nevertheless, the BNT162b2 vaccine had higher efficacy in preventing infection (42.6% vs. 15.0%) and deaths (90.4% vs. 64.8%) compared to CoronaVac.

Conclusion

The results of our study suggest that vaccination against SARS-CoV-2 in patients on chronic hemodialysis was effective in preventing infection and death associated with COVID-19.

Perceived stress and physiological consistency during mental stress exercises and controlled breathing

Introduction

The measurement of the physiological coherence, the order and the quality of the connection of complex systems such as the cardiac and the respiratory system, varies in situations of stress and relaxation.

Objectives

We aim to assess changes in physiological coherence and perception of stress during mental stress and directed breathing exercises.

Methods

Repeated-measures study in healthy adults without prior training in breathing techniques, aged between 18 and 65 years of both sexes who were evaluated in three situations: baseline, mental stress (Stroop test and successive subtractions), and directed breathing, during which were captured heart rate and respiratory signals to estimate physiological coherence and the participants rated the perceived stress at each moment.

Results

34 participants were analyzed, 59% women, with a median age of 36 years (Rq = 13). During mental stress tasks, the median for physiological coherence was similar to baseline coherence but increased significantly with five minutes of directed breathing exercises (38% vs. 63% p <0.0001). The highest perception of stress was during successive subtractions (Me 7, Rq = 4) and the lowest during directed breathing exercises (Me 2 Rq = 3.0). The correlation was sought between physiological coherence and perception of stress during each of the four moments of the study. Basal (Rho Spearman -0.05, p 0.54); Stroop (Rho -0.17, p 0.03); successive subtractions (Rho 0.50, p 0.77); and directed breathing (Rho -0.28, p 0.09).

Conclusions

A correlation was found between physiological coherence and perception of stress during the Stroop test; however, no association was found.

Disclosure

No significant relationships.

Survival study and factors associated with mortality in Chilean patients on peritoneal dialysis infected with SARS-CoV-2

The Covid-19 pandemic has been responsible for millions of deaths worldwide. Patients with comorbidities- such as those on peritoneal dialysis (PD)- present higher morbidity and mortality than the general population. We prospectively evaluated all Chilean patients on PD (48 centres) and followed those who had Covid-19 from the beginning of the Covid-19 pandemic in Chile (March 2020) to January 2021 (start of vaccination campaign). We described demographic history, comorbidities, factors related to infection, need for hospitalisation and death due to Covid-19. During the study period, 106 adults on PD were infected by SARS-CoV-2, with a mean age of 53.1 (±16.3) and of which 53.9% were female. From that group, 54.8% required hospitalisation and 24.5% (n = 26) died due to Covid-19. Most of the patients (63.4%) were infected at home and 22.8% during hospitalisation for other reasons. There was a significant association for Covid-19 mortality with: being ≥60 years old, diabetes, time on PD ≥5 years, need for hospitalisation and hospital-acquired infection. At 90 days of follow-up, all deaths associated to Covid-19 occurred before 40 days. We conclude that patients on PD without Covid-19 vaccination have a high mortality and need for hospitalisation associated to Covid-19. To avoid this negative outcome, it is necessary to intensify strategies to avoid contagion, especially in those ≥60 years old, with diabetes and/or ≥5 years spent on PD.

PcrA Dissociates RecA Filaments and the SsbA and RecO Mediators Counterbalance Such Activity

PcrA depletion is lethal in wild-type Bacillus subtilis cells. The PcrA DNA helicase contributes to unwinding RNA from the template strand, backtracking the RNA polymerase, rescuing replication-transcription conflicts, and disassembling RecA from single-stranded DNA (ssDNA) by poorly understood mechanisms. We show that, in the presence of RecA, circa one PcrA/plasmid-size circular ssDNA (cssDNA) molecule hydrolyzes ATP at a rate similar to that on the isolated cssDNA. PcrA K37A, which poorly hydrolyses ATP, fails to displace RecA from cssDNA. SsbA inhibits and blocks the ATPase activities of PcrA and RecA, respectively. RecO partially antagonizes and counteracts the negative effect of SsbA on PcrA- and RecA-mediated ATP hydrolysis, respectively. Conversely, multiple PcrA molecules are required to inhibit RecA·ATP-mediated DNA strand exchange (DSE). RecO and SsbA poorly antagonize the PcrA inhibitory effect on RecA·ATP-mediated DSE. We propose that two separable PcrA functions exist: an iterative translocating PcrA monomer strips RecA from cssDNA to prevent unnecessary recombination with the mediators SsbA and RecO balancing such activity; and a PcrA cluster that disrupts DNA transactions, as RecA-mediated DSE.

Bacillus subtilis RecA, DisA, and RadA/Sms Interplay Prevents Replication Stress by Regulating Fork Remodeling

Reviving Bacillus subtilis spores require the recombinase RecA, the DNA damage checkpoint sensor DisA, and the DNA helicase RadA/Sms to prevent a DNA replication stress. When a replication fork stalls at a template lesion, RecA filaments onto the lesion-containing gap and the fork is remodeled (fork reversal). RecA bound to single-strand DNA (ssDNA) interacts with and recruits DisA and RadA/Sms on the branched DNA intermediates (stalled or reversed forks), but DisA and RadA/Sms limit RecA activities and DisA suppresses its c-di-AMP synthesis. We show that RecA, acting as an accessory protein, activates RadA/Sms to unwind the nascent lagging-strand of the branched intermediates rather than to branch migrate them. DisA limits the ssDNA-dependent ATPase activity of RadA/Sms C13A, and inhibits the helicase activity of RadA/Sms by a protein-protein interaction. Finally, RadA/Sms inhibits DisA-mediated c-di-AMP synthesis and indirectly inhibits cell proliferation, but RecA counters this negative effect. We propose that the interactions among DisA, RecA and RadA/Sms, which are mutually exclusive, contribute to generate the substrate for replication restart, regulate the c-di-AMP pool and limit fork restoration in order to maintain cell survival.

[Rhabdomyolysis as the presentation form of COVID-19 infection. Report of one case]

COVID-19 infection causes a systemic inflammatory response, which mainly presents as a febrile syndrome with respiratory involvement. We report a 37-year-old male who consulted for myalgia, nausea and epigastric pain lasting three days. On admission, he had crepitations at the lung bases. The initial laboratory showed a creatine kinase of 62,768 U/L, a LDH of 1,110 IU/L, a creatinine a 2.1 mg/dL, an aspartate aminotransferase of 1,347 IU/L, a D-dimer of 1,140 ng/mL, a ferritin of 1,201 ng/mL and a lymphocyte count of 810 cells/mm3. The chest CT scan was compatible with multifocal pneumonia, suggesting a COVID-19 infection. COVID-19 PCR was positive. The patient was managed with hydration, sodium bicarbonate, ceftriaxone, and azithromycin, with a good clinical response.

DisA Restrains the Processing and Cleavage of Reversed Replication Forks by the RuvAB-RecU Resolvasome

DNA lesions that impede fork progression cause replisome stalling and threaten genome stability. Bacillus subtilis RecA, at a lesion-containing gap, interacts with and facilitates DisA pausing at these branched intermediates. Paused DisA suppresses its synthesis of the essential c-di-AMP messenger. The RuvAB-RecU resolvasome branch migrates and resolves formed Holliday junctions (HJ). We show that DisA prevents DNA degradation. DisA, which interacts with RuvB, binds branched structures, and reduces the RuvAB DNA-dependent ATPase activity. DisA pre-bound to HJ DNA limits RuvAB and RecU activities, but such inhibition does not occur if the RuvAB- or RecU-HJ DNA complexes are pre-formed. RuvAB or RecU pre-bound to HJ DNA strongly inhibits DisA-mediated synthesis of c-di-AMP, and indirectly blocks cell proliferation. We propose that DisA limits RuvAB-mediated fork remodeling and RecU-mediated HJ cleavage to provide time for damage removal and replication restart in order to preserve genome integrity.

Asociación Mexicana de Hepatología A.C. Clinical guideline on hepatitis B

Hepatitis B virus (HBV) infection continues to be a worldwide public health problem. In Mexico, at least three million adults are estimated to have acquired hepatitis B (total hepatitis B core antibody [anti-HBc]-positive), and of those, 300,000 active carriers (hepatitis B surface antigen [HBsAg]-positive) could require treatment. Because HBV is preventable through vaccination, its universal application should be emphasized. HBV infection is a major risk factor for developing hepatocellular carcinoma. Semi-annual liver ultrasound and serum alpha-fetoprotein testing favor early detection of that cancer and should be carried out in all patients with chronic HBV infection, regardless of the presence of advanced fibrosis or cirrhosis. Currently, nucleoside/nucleotide analogues that have a high barrier to resistance are the first-line therapies.

Asociación Mexicana de Hepatología A.C. Clinical guideline on hepatitis B

Hepatitis B virus (HBV) infection continues to be a worldwide public health problem. In Mexico, at least three million adults are estimated to have acquired hepatitis B (total hepatitis B core antibody [anti-HBc]-positive), and of those, 300,000 active carriers (hepatitis B surface antigen [HBsAg]-positive) could require treatment. Because HBV is preventable through vaccination, its universal application should be emphasized. HBV infection is a major risk factor for developing hepatocellular carcinoma. Semi-annual liver ultrasound and serum alpha-fetoprotein testing favor early detection of that cancer and should be carried out in all patients with chronic HBV infection, regardless of the presence of advanced fibrosis or cirrhosis. Currently, nucleoside/nucleotide analogues that have a high barrier to resistance are the first-line therapies.

P–403 Sodium tungstate increases embryo adhesion through a direct effect on endometrial cells

Study question

Does sodium tungstate treatment induce a change in endometrial cells’ capacity to implant trophoblasts?

Summary answer

Administration of sodium tungstate to endometrial cells increases trophoblast adhesion.

What is known already

Sodium tungstate (ST) has shown its capacity to modulate the activity of cytokines, such as leptin, an activator of an obligatory signalling cascade in the embryo-implantation process. STAT3, a signal transducer molecule critical for the embryo implantation process, is also known to be activated by ST. Still, ST’s effect on implantation using biological systems has never been studied. Embryo implantation process and endometrium roles are complicated to study in vivo due to a lack of animal models and appropriate techniques. In vitro techniques using immortalised cell lines allows a first approach to study early implantation stages, such as embryo adhesion.

Study design, size, duration

An in vitro study was carried out using a human endometrial carcinoma cell line (HEC–1-A) treated with sodium tungstate for 24 and 48h, and choriocarcinoma cell spheroids (JAr). Different times of treatment and concentrations were studied. Each experiment was performed in triplicate.

Participants/materials, setting, methods

Confluent endometrial HEC–1-A cultures were treated with ST at concentrations (0–150mM) and withaferin A (1mM), negative control for embryo adhesion. After the treatment period, HEC–1-A cultures were washed with ST-free culture medium to eliminate ST. Immediately, 15 JAr trophoblast spheroids were added to cultures and coincubated with gentle agitation for 30, 60 and 90 minutes. An inverted light microscope was used to count adhered and floating spheroids, and determine the trophoblast adherence ratio.

Main results and the role of chance

HEC–1-A cells treated with ST showed normal morphology and growth at all doses except 150mM. At the highest dose tested, the cells’ culture was still viable (negative blue trypan staining) and maintained morphology, but the adhesion to the plate surface was affected. Doses from 0.15 to 15mM were used to perform adhesion assays.

HEC–1-A cells treated with ST for 24h showed an increased capacity to adhere JAr trophoblast spheroids. Adhesion rates reached significant differences at doses of 1.5 and 15mM after 60 and 90 minutes of coincubation. After 90 minutes, untreated cells reached 32.8% adhesion rate, while 1.5 and 15mM ST-treated cells reached 54.6% and 53.4% respectively (p &lt; 0.05 ST vs untreated). Thus, the increment of trophoblast adhesion rate induced by ST reached 66%. Lower adhesion rates were observed after 60 minutes of coincubation but were also significant with a relative increase of 49.1% at 1.5mM and 50.5% at 1.5mM when compared with untreated cells (p &lt; 0.05)

Longer treatments (48h) showed similar trends to 24h-treatments, but with a lower extent of ST effect on HEC–1-A receptivity. Maximum adhesion rates were also observed at 90 minutes of coincubation and 1.5 and 15mM doses. The Mean adhesion rate increase was &gt;40% with both doses. Limitations, reasons for caution: The current study is the first approach to evaluate sodium tungstate effect on endometrium using an in vitro model. Future research using in vivo models should be performed to assess sodium tungstate effect on endometrium receptivity and its potential as a fertility treatment.

Wider implications of the findings: We conclude that the direct effect of sodium tungstate on endometrial cells increases embryo adhesion rate. These results open a new research line to a potential treatment in human reproduction management with sodium tungstate to solve the unmet need of inducing embryo implantation.

Trial registration number

Not applicable

Nucleoid-associated Rok differentially affects chromosomal transformation on Bacillus subtilis recombination-deficient cells

Rok, a Bacillus subtilis nucleoid-associated protein (NAP), negatively regulates competence development and silences xenogeneic genes. We show that rok inactivation increases rpoB482 natural intraspecies chromosomal transformation (CT) and plasmid transformation to a different extent. In ΔaddAB, ΔrecO, recF15, ΔrecU, ΔruvAB or rec⁺ cells intraspecies CT significantly increases, but the ΔrecD2 mutation reduces, and the ΔrecX, ΔradA or ΔdprA mutation further decreases CT in the Δrok context when compared to rok⁺ cells. These observations support the idea that rok inactivation, by altering the topology of the recipient DNA, differentially affects the integration of homologous DNA in rec-deficient strains, and in minor extent the competent subpopulation size. The impairment of other NAP (Hbsu or LrpC) also increased intra- and interspecies CT (nonself-DNA, ~8% nucleotide sequence divergence) in rec⁺ cells, but differentially reduced both types of CTs in certain rec-deficient strains. We describe that rok inactivation significantly stimulates intra and interspecies CT but differentially reduces them in transformation-deficient cells, perhaps by altering the nucleoid architecture. We extend the observation to other NAPs (Hbsu, LrpC).

Recommendations for streamlining precision medicine in breast cancer care in Latin America

Background

The incidence of breast cancer (BC) in LMICs has increased by more than 20% within the last decade. In areas such as Latin America (LA), addressing BC at national levels evoke discussions surrounding fragmented care, limited resources, and regulatory barriers. Precision Medicine (PM), specifically companion diagnostics (CDx), links disease diagnosis and treatment for better patient outcomes. Thus, its application may aid in overcoming these barriers.

Recent findings

A panel of LA experts in fields related to BC and PM were provided with a series of relevant questions to address prior to a multi‐day conference. Within this conference, each narrative was edited by the entire group, through numerous rounds of discussion until a consensus was achieved. The panel proposes specific, realistic recommendations for implementing CDx in BC in LA and other LMIC regions. In these recommendations, the authors strived to address all barriers to the widespread use and access mentioned previously within this manuscript.

Conclusion

This manuscript provides a review of the current state of CDx for BC in LA. Of most importance, the panel proposes practical and actionable recommendations for the implementation of CDx throughout the Region in order to identify the right patient at the right time for the right treatment.

Effects of sub-optimal illumination in plants. Comprehensive chlorophyll fluorescence analysis

The fluorescence signals emitted by chlorophyll molecules of plants is a promising non-destructive indicator of plant physiology due to its close link to photosynthesis. In this work, a deep photophysical study of chlorophyll fluorescence was provided, to assess the sub-optimal illumination effects on three plant species: L. sativa, A. hybridus and S. dendroideum. In all the cases, low light (LL) treatment induced an increase in pigment content. Fluorescence ratios - corrected by light reabsorption processes - remained constant, which suggested that photosystems stoichiometry was conserved. For all species and treatments, quantum yields of photophysical decay remained around 0.2, which meant that the maximum possible photosynthesis efficiency was about 0.8. L. sativa (C3) acclimated to low light illumination, displayed a strong increase in the LHC size and a net decrease in the photosynthetic efficiency. A. hybridus (C4) was not appreciably stressed by the low light availability whereas S. dendroideum (CAM), decreased its antenna and augmented the quantum yield of primary photochemistry. A novel approach to describe NPQ relaxation kinetics was also presented here and used to calculate typical deactivation times and amplitudes for NPQ components. LL acclimated L. sativa presented a much larger deactivation time for its state-transition-related quenching than the other species. Comprehensive fluorescence analysis allowed a deep study of the changes in the light-dependent reactions of photosynthesis upon low light illumination treatment.

Bacillus subtilis PcrA Helicase Removes Trafficking Barriers

Bacillus subtilis PcrA interacts with the RNA polymerase and might contribute to mitigate replication-transcription conflicts (RTCs). We show that PcrA depletion lethality is partially suppressed by rnhB inactivation, but cell viability is significantly reduced by rnhC or dinG inactivation. Following PcrA depletion, cells lacking RnhC or DinG are extremely sensitive to DNA damage. Chromosome segregation is not further impaired by rnhB or dinG inactivation but is blocked by rnhC or recA inactivation upon PcrA depletion. Despite our efforts, we could not construct a ΔrnhC ΔrecA strain. These observations support the idea that PcrA dismantles RTCs. Purified PcrA, which binds single-stranded (ss) DNA over RNA, is a ssDNA-dependent ATPase and preferentially unwinds DNA in a 3'→5'direction. PcrA unwinds a 3'-tailed RNA of an RNA-DNA hybrid significantly faster than that of a DNA substrate. Our results suggest that a replicative stress, caused by mis-incorporated rNMPs, indirectly increases cell viability upon PcrA depletion. We propose that PcrA, in concert with RnhC or DinG, contributes to removing spontaneous or enzyme-driven R-loops, to counteract deleterious trafficking conflicts and preserve to genomic integrity.