bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine-tuning functional syndromes for stressful environments: lessons on survival from the South African resurrection plant Myrothamnus flabellifolia
Authors: Marks Rose A. , Mbobe Mpho , Greyling Marilize , Pretorius Jennie , McLetchie D. Nicholas , VanBuren Robert , Farrant Jill M. 
Published: September 2021

ABSTRACTResilience to abiotic stress is associated with a suite of functional traits related to defense and longevity. Stress tolerant plants are generally slow growing with extended leave lifespans and reduced allocation to reproduction. Resurrection plants are ideal systems to test for trade-offs associated with stress tolerance due to their extreme resiliency. While, growth defense trade-offs are well-characterized, few studies have tested for natural variation associated with tolerating the harshest environments. Here, we surveyed a suite of functional traits related to stress tolerance, leaf economics, and reproductive allocation in natural populations of the South African resurrection plant Myrothamnus flabellifolia. We selected three distinct field sites in South Africa ranging from mesic to xeric. Despite considerable environmental variation across the study area, M. flabellifolia plants were extremely and similarly stress tolerant at all sites. However, we detected notable variation in other life history and morphological traits. Plants in more mesic sites were larger, faster growing, and had more inflorescences. In contrast, plants from the most xeric sites appeared to invest more in persistence and defense, with lower growth rates and less reproductive allocation. Together, this suggests that desiccation tolerance is a binary trait in M. flabellifolia with little natural variation, but that other phenotypes are more labile. The trait syndromes exhibited by plants at the different study sites align with general expectations about growth defense tradeoffs associated with the colonization of extreme environments. We show that plants from the least stressful sites are more reproductive and faster growing, whereas plants from the most stressful sites were slower growing and less reproductive. These findings suggest that M. flabellifolia plants are finely tuned to their environment.
Non-linear functional brain co-activations in short-term memory distortion tasks
Authors: Ceglarek Anna , Ochab Jeremi K. , Cifre Ignacio , Fąfrowicz Magdalena , Sikora-Wachowicz Barbara , Lewandowska Koryna , Bohaterewicz Bartosz , Marek Tadeusz , Chialvo Dante R. 
Published: September 2021

AbstractRecent works shed light on the neural correlates of true and false recognition and the influence of time of day on cognitive performance. The current study aimed to investigate the modulation of the false memory formation by the time of day using a non-linear correlation analysis originally designed for fMRI resting-state data. Fifty-four young and healthy participants (32 females, mean age: 24.17 y.o., SD: 3.56 y.o.) performed in MR scanner the modified Deese-Roediger-McDermott paradigm in short-term memory during one session in the morning and another in the evening. Subjects’ responses were modeled with a general linear model, which includes as a predictor the non-linear correlations of regional BOLD activity with the stimuli, separately for encoding and retrieval phases. The results show the dependence of the non-linear correlations measures with the time of day and the type of the probe. In addition, the results indicate differences in the correlations measures with hippocampal regions between positive and lure probes. Besides confirming previous results on the influence of time-of-day on cognitive performance, the study demonstrates the effectiveness of the non-linear correlation analysis method for the characterization of fMRI task paradigms.
Low dose hydroxychloroquine prophylaxis for COVID-19 – a prospective study
Authors:   RE-HCP2 COVID study group, Agarwal Mayank , Ranka Rajat , Panda Prasan Kumar , Kumar Ajay , Chikara Gaurav , Sharma Suresh K , Negi Rizu , Samanta Ramanuj , Walia Rohit , Bahurupi Yogesh Arvind , Saha Sarama , Dhar Minakshi , Sharma Prakhar , Gupta Arvind Kumar , Mishra UB , Gupta Manoj Kumar , Kant Ravi 
Published: September 2021

AbstractBackgroundSince the outbreak of COVID-19 pandemic, the world began a frantic search for possible prophylactic options. While trials on hydroxychloroquine (HCQ) prophylaxis are ongoing, concrete evidence is lacking. The study aimed to determine the relative efficacy of various doses of oral HCQ in prophylaxis and mitigating the severity of COVID-19 in healthcare workers.MethodsThis was a prospective cohort with four arms (high, medium, low dose, and control) of HCQ prophylaxis, used by healthcare workers at a tertiary care center in India. Participants were grouped as per their opting for any one arm on a voluntary basis as per institute policy under the Government guidance. The outcomes studied were COVID-19 positivity by RT-PCR and its severity assessed by WHO COVID-19 severity scale.ResultsTotal 486 participants were enrolled, of which 29 (6%) opted for low dose, 2 (<1%) medium dose, and none for high dose HCQ while 455 (93.6%) were in the control arm. Of the 164 participants who underwent RT-PCR, 96 (58.2%) tested positive. Out of these 96 positive cases, the majority of them (79 of 96 [82.3%]) were ambulatory and were managed conservatively at home. Only 17.7% (17 of 96) participants, all of them from the control group, required hospitalization with the mild-moderate disease. None of the participants had severe disease, COVID-related complications, ICU stay, or death. The difference in the outcome assessed amongst the various arms was statistically insignificant (p value >0.05).ConclusionThis single-center study demonstrated that HCQ prophylaxis in healthcare workers does not cause a significant reduction in COVID-19 as well as mitigating its severity in those infected. At present, most of the trials have not shown any benefit. The debate continues to rage, should HCQ prophylaxis be given to healthcare workers for chemoprophylaxis?
Regional Cell Atlas of Human Intestine Shapes Distinct Immune Surveillance
Authors: Wang Yue , Yu Yanbo , Li Lixiang , Zheng Mengqi , Zhou Jiawei , Gong Haifan , Feng Bingcheng , Qu Junyan , Li Zhen , Ji Rui , Lu Ming , Yang Xiaoyun , Zuo Xiuli , Li Shiyang , Li Yanqing 
Published: September 2021

AbstractRegional intestinal immune surveillance remains obscure. In this study, we integrated single-cell RNA sequencing and spatial transcriptomics to create a regional atlas of fetal and adult intestines, consisting of 59 cell subsets, of which eight new subsets and ILCs transition states were identified. Results revealed that microenvironment determines in-situ cell differentiation and shapes the regional molecular characteristics, allowing different intestinal segments with diverse functions. We characterized the regional expression of mucins, immunoglobulins, and antimicrobial peptides (AMPs) and their shift during development and in inflammatory bowel disease. Notably, α-defensins expressed most abundantly in small intestinal LGR5+ stem cells, rather than in Paneth cells, and down-regulated as cell maturing. Common upstream transcription factors controlled the AMPs expression, illuminating the concurrent change of AMPs during epithelial differentiation, and the spatial co-expression patterns. We demonstrated the correspondence of cell focus of risk genes to diseases’ location susceptibility and identified distinct cell-cell crosstalk and spatial heterogeneity of immune cell homing in different gut segments. Overall, a cross-spatiotemporal approach to transcriptomes at single-cell resolution revealed that the regional milieu of the human intestine determined cellular and molecular cues of immune surveillance, dictating gut homeostasis and disease.
The Lyme Disease agent co-opts adiponectin receptor-mediated signaling in its arthropod vector
Authors: Tang Xiaotian , Cao Yongguo , Arora Gunjan , Hwang Jesse , Sajid Andaleeb , Brown Courtney L. , Mehta Sameet , Marín-López Alejandro , Chuang Yu-Min , Wu Ming-Jie , Ma Hongwei , Pal Utpal , Narasimhan Sukanya , Fikrig Erol 
Published: September 2021

AbstractAdiponectin-mediated pathways contribute to mammalian homeostasis; however, little is known about adiponectin and adiponectin receptor signaling in arthropods. In this study, we demonstrate that Ixodes scapularis ticks have an adiponectin receptor-like protein (ISARL) but lack adiponectin – suggesting activation by alternative pathways. ISARL expression is significantly upregulated in the tick gut after Borrelia burgdorferi infection suggesting that ISARL-signaling may be co-opted by the Lyme disease agent. Consistent with this, RNA interference (RNAi)-mediated silencing of ISARL significantly reduced the B. burgdorferi burden in the tick. RNA-seq-based transcriptomics and RNAi assays demonstrate that ISARL-mediated phospholipid metabolism by phosphatidylserine synthase I is associated with B. burgdorferi survival. Furthermore, the tick complement C1q-like protein 3 interacts with ISARL, and B. burgdorferi facilitates this process. This study identifies a new tick metabolic pathway that is connected to the life cycle of the Lyme disease spirochete.Significance StatementAdiponectin binds to adiponectin receptors and participates in glucose and lipid metabolism in mammals. In this study, we found that ticks have an adiponectin receptor-like protein but lack adiponectin. Importantly, we demonstrated that the Lyme disease agent, Borrelia burgdorferi, takes advantage of the adiponectin receptor signaling pathway to establish infection in its arthropod vector, Ixodes scapularis. Our study sheds light on the understanding of Borrelia-tick interactions and provides insights into how a human infectious disease agent may evolve to manipulate host metabolism for its own benefits. Understanding this pathway may lead to new ways to interfere with the Borrelia life cycle, and this mechanism may be applicable to additional microbes that are transmitted by ticks, mosquitoes or other arthropods.
High interaction valency ensures cohesion and persistence of a microtubule +TIP body at the plus-end of a single specialized microtubule in yeast
Authors: Meier Sandro M. , Farcas Ana-Maria , Kumar Anil , Ijavi Mahdiye , Bill Robert T. , Stelling Jörg , Dufresne Eric , Steinmetz Michel O. , Barral Yves 
Published: September 2021

AbstractMicrotubule plus-end tracking proteins (+TIPs) control microtubule specialization and are as such essential notably during eukaryotic cell division. Here, we investigated interactions and functions of the budding yeast Kar9 network consisting of the core +TIPs components Kar9 (functional homologue of APC, MACF, and SLAIN), Bim1 (orthologue of EB1), and Bik1 (orthologue of CLIP-170). Our data indicate that a redundant, multivalent web of interactions links the three +TIPs together to form a “Kar9 body” at the tip of a single cytoplasmic microtubule. They further suggest that this body is a liquid-like condensate, allowing it to persist on both growing and shrinking microtubule tips, and functions as a mechanical coupling device between microtubules and actin cables during mitosis. Our study underlines the power of dissecting the web of low-affinity interactions driving liquid-liquid phase separation of proteins in order to demonstrate the importance and establish the functional roles of condensation processes in vivo.
Gene duplication and rate variation in the evolution of plastid ACCase and Clp genes in angiosperms
Authors: Williams Alissa M. , Carter Olivia G. , Forsythe Evan S. , Mendoza Hannah K. , Sloan Daniel B. 
Published: September 2021

AbstractWhile the chloroplast (plastid) is known for its role in photosynthesis, it is also involved in many other metabolic pathways essential for plant survival. As such, plastids contain an extensive suite of enzymes required for non-photosynthetic processes. The evolution of the associated genes has been especially dynamic in flowering plants (angiosperms), including examples of gene duplication and extensive rate variation. We examined the role of ongoing gene duplication in two key plastid enzymes, the acetyl-CoA carboxylase (ACCase) and the caseinolytic protease (Clp), responsible for fatty acid biosynthesis and protein turnover, respectively. In plants, there are two ACCase complexes—a homomeric version present in the cytosol and a heteromeric version present in the plastid. Duplications of the nuclear-encoded homomeric ACCase gene and retargeting of one resultant protein to the plastid have been previously reported in multiple species. We find that these retargeted homomeric ACCase proteins exhibit elevated rates of sequence evolution, consistent with neofunctionalization and/or relaxation of selection. The plastid Clp complex catalytic core is composed of nine paralogous proteins that arose via ancient gene duplication in the cyanobacterial/plastid lineage. We show that further gene duplication occurred more recently in the nuclear-encoded core subunits of this complex, yielding additional paralogs in many species of angiosperms. Moreover, in six of eight cases, subunits that have undergone recent duplication display increased rates of sequence evolution relative to those that have remained single copy. We also compared substitution patterns between pairs of Clp core paralogs to gain insight into post-duplication evolutionary routes. These results show that gene duplication and rate variation continue to shape the plastid proteome.
Allosteric modulation of the adenosine A2A receptor by cholesterol
Authors: Huang Shuya Kate , Almurad Omar , Pejana Reizel J. , Morrison Zachary A. , Pandey Aditya , Picard Louis-Philippe , Nitz Mark , Sljoka Adnan , Prosser R. Scott 
Published: September 2021

AbstractCholesterol is a major component of the cell membrane and commonly regulates membrane protein function. Here, we investigate how cholesterol modulates the conformational equilibria and signaling of the adenosine A2A receptor (A2AR) in reconstituted phospholipid bilayers. GTP hydrolysis assays show that cholesterol is a weak positive allosteric modulator of A2AR, as seen through enhanced basal signaling and a small decrease in agonist EC50. Fluorine nuclear magnetic resonance (19F NMR) spectroscopy suggests that this enhancement arises from an increase in the receptor’s active state populations and stronger G protein coupling. 19F NMR of fluorinated cholesterol analogs reveals transient and non-specific interactions with A2AR, indicating a lack of high-affinity binding sites or direct allosteric modulation. This is confirmed by computational analysis which suggests that cholesterol contacts confer a weak and possibly negative allosteric effect. The combined results suggest that the observed cholesterol allostery in A2AR is likely a result of indirect membrane effects through cholesterol-mediated changes in membrane properties, as shown by membrane fluidity measurements and high-pressure NMR.
Isolation, identification and molecular characterization of Aeromonas spp. from farmed loach (Misgurnus anguillicaudatus)
Authors: Wang Xin , Pan Jiwen , Chen Liqing , Li Roushan , Han Yu , Di Zihao , Ling Bo , Ahmad Ashfaq , Yang Nuo , Fan Lixia , Li Qian , Zeng Jifeng , Guo Guiying , Zheng Jiping 
Published: September 2021

AbstractGram-negative Aeromonas bacteria is known to contaminate aquaculture products and retains the ability to infect wide range of host including fishes, shrimps and humans. This study is designed to evaluate the presence of Aeromonas in healthy loaches (Misgurnus anguillicaudatus) collected from the markets in Hainan and Guangdong provinces of China. Based on the molecular sequencing and phylogenetic analysis with single 16S rRNA and concatenated genes (gyrA and ropD), 104 isolates were identified as Aeromonas species followed by further classification to A. veronii (83.65%), A. jandaei (9.62%), A. hydrophila (3.85%) and A. allosaccharophila (2.88%). More than half of the isolates displayed hemolytic activity of 87.5% and were able to form moderate biofilm (78.26%). Fourteen antibiotics from ten representative classes were screened that demonstrated complete resistance to ampicillin, 89.4% and 68.3% to lincomycin and nalidixic acid. Moreover, a notable detection and prevalence was found in screening of ten virulence-related and nine resistance genes. To our knowledge, it is the first report of its kind demonstrating potential threat of the commercial loaches carrying Aeromonas to human health. These findings will assist professionals working in clinical settings to optimize their prescription accordingly and researchers to access the impacts of Aeromonas resistance on human health.ImportanceThis study demonstrates high infection rate of loaches by Aeromonas spp. in Hainan and Guangdong provinces of China.The most prevalent species was Aeromonas veronii.Most of the isolates displayed hemolytic activity and formed moderate biofilm.Multiple virulence genes, resistance genes and multi-antibiotic resistance were detected.Aeromonads risks should be considered in loach industry.
Assessment of CAR-T mediated and targeted cytotoxicity in 3D microfluidic TBNC co-culture models for combination therapy
Authors: Paterson K. , Paterson S. , Mulholland T. , Coffelt S. B. , Zagnoni M. 
Published: September 2021

AbstractChimeric antigen receptor (CAR)-T cell therapy is efficacious against many hematological malignancies; however, their therapeutic application to treat solid tumors presents further challenges. A better understanding of how the solid tumor microenvironment (TME) impacts CAR-T anti-tumor effects would enable the selection of effective combination therapies to decipher the optimal course of treatment for patients and to better engineer CAR-Ts. Classical 2Din vitromodels do not provide sufficient recapitulation of the native human TME, andin vivomodels, such as patient-derived xenografts, are costly, complex and labor intensive. Here, we present a novel 3D, miniaturized assay for the evaluation of EGFR-targeted CAR-T cell cytotoxicity and specificity on tumor-stroma triple-negative breast cancer models in microfluidic devices. CAR-T cells were shown to home towards EGFR-expressing cancer cells to elicit a cytotoxic effect, whilst leaving low EGFR-expressing fibroblasts viable, an effect which was enhanced through combination anti-PD-L1 therapy and carboplatin chemotherapy. Hence, we propose this proof-of-concept immunoassay as a future preclinical screening tool for the development of novel immunotherapeutics and for use in personalized medicine.
Convergent clonal selection of donor- and recipient-derived CMV-specific T cells in hematopoietic stem cell transplant patients
Authors: Erickson Jami R. , Stevens-Ayers Terry , Mair Florian , Edmison Bradley , Boeckh Michael , Bradley Philip , Prlic Martin 
Published: September 2021

AbstractCompetition between antigen-specific T cells for peptide:MHC (p:MHC) complexes shapes the ensuing T cell response. Mouse model studies provided compelling evidence that competition is a highly effective mechanism controlling the activation of naïve T cells. However, assessing the effect of T cell competition in the context of a human infection requires defined pathogen kinetics and trackable naïve and memory T cell populations of defined specificity. A unique cohort of non-myeloablative hematopoietic stem cell transplant (nmHSCT) patients allowed us to assess T cell competition in response to CMV reactivation, which was documented with detailed virology data. In our cohort, HSCT donors and recipients were CMV-seronegative and -positive, respectively, thus providing genetically distinct memory and naïve T cell populations. We used single-cell transcriptomics to track donor versus recipient-derived T cell clones over the course of 90 days. We found that donor-derived T cell clones proliferated and expanded substantially following CMV-reactivation. However, for immunodominant CMV epitopes, recipient-derived memory T cells remained the overall dominant population. This dominance was maintained despite more robust clonal expansion of donor-derived T cells in response to CMV reactivation. Interestingly, the donor-derived T cells that were recruited into these immunodominant memory populations shared strikingly similar TCR properties with the recipient-derived memory T cells. This selective recruitment of identical and nearly identical clones from the naïve into the immunodominant memory T cell pool suggests that competition does not interfere with rejuvenating a memory T cell population, but results in selection of convergent clones to the memory T cell pool.SignificanceAn existing memory T cell population specific for a single epitope is sufficient to effectively curtail responses to any new antigens if the original epitope is present in a vaccination regimen or heterologous infections. We asked if T cell competition precludes recruitment of any new, naïve T cells to an existing memory T cell pool in context of CMV-specific T cell responses in a cohort of transplant patients. Our data indicate that competition does not prevent recruitment of naïve T cells into the memory T cell pool, but selects for T cells with nearly or fully congruent T cell receptor specificities. We discuss the implications of rejuvenating a memory T cell pool while preserving the T cell receptor repertoire.
Deep learning and CRISPR-Cas13d ortholog discovery for optimized RNA targeting
Authors: Wei Jingyi , Lotfy Peter , Faizi Kian , Baungaard Sara , Gibson Emily , Wang Eleanor , Slabodkin Hannah , Kinnaman Emily , Chandrasekaran Sita , Kitano Hugo , Durrant Matthew G. , Duffy Connor V. , Hsu Patrick D. , Konermann Silvana 
Published: September 2021

AbstractTranscriptome engineering technologies that can effectively and precisely perturb mammalian RNAs are needed to accelerate biological discovery and RNA therapeutics. However, the broad utility of programmable CRISPR-Cas13 ribonucleases has been hampered by an incomplete understanding of the design rules governing guide RNA activity as well as cellular toxicity resulting from off-target or collateral RNA cleavage. Here, we sought to characterize and develop Cas13d systems for efficient and specific RNA knockdown with low cellular toxicity in human cells. We first quantified the performance of over 127,000 RfxCas13d (CasRx) guide RNAs in the largest-scale screen to date and systematically evaluated three linear, two ensemble, and two deep learning models to build a guide efficiency prediction algorithm validated across multiple human cell types in orthogonal validation experiments (https://www.RNAtargeting.org). Deep learning model interpretation revealed specific sequence motifs at spacer position 15-24 along with favored secondary features for highly efficient guides. We next identified 46 novel Cas13d orthologs through metagenomic mining for activity and cytotoxicity screening, discovering that the metagenome-derived DjCas13d ortholog achieves low cellular toxicity and high transcriptome-wide specificity when deployed against high abundance transcripts or in sensitive cell types, including human embryonic stem cells, neural progenitor cells, and neurons. Finally, our Cas13d guide efficiency model successfully generalized to DjCas13d, highlighting the utility of a comprehensive approach combining machine learning with ortholog discovery to advance RNA targeting in human cells.