bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical and signaling mechanisms that guide pre-implantation embryo movement
Authors: Flores Diana , Madhavan Manoj , Wright Savannah , Arora Ripla 
Published: April 2020

ABSTRACTHow a mammalian embryo determines and arrives at its site of attachment is a mystery that has puzzled researchers for decades. Additionally, in multiparous species, embryos face a unique challenge of achieving adequate spacing to avoid competition for maternal resources. Using our enhanced confocal imaging and 3D image reconstruction technology, we evaluate murine embryo location in the uterus along the longitudinal oviductal-cervical axis. Our analysis reveals three distinct pre-implantation stages: a) Embryo entry; b) Unidirectional movement of embryo clusters; and c) Bidirectional scattering and spacing of embryos. We show that unidirectional movement of embryo clusters is facilitated by a mechanical stimulus of the embryo as a physical object and is regulated by adrenergic uterine smooth muscle contractions. Embryo scattering, on the other hand, relies on embryo-uterine communication reliant on the LPAR3 signaling pathway and is independent of adrenergic muscle contractions. We propose that the presence of embryo clusters in the uterine horn provides an opportunity for the uterus to sense and count the embryos, followed by scattering and spacing these embryos along the given length of the horn. Thus, uterine implantation sites in mice are neither random nor predetermined but are guided by the number of embryos entering the uterine lumen. These studies have implications for understanding how embryo-uterine communication is key to determining an optimal implantation site, which is necessary for the success of a pregnancy.Significance StatementIn mammals that carry multiple offspring in one gestation, embryos seemingly acquire even embryo spacing. Such even distribution would imply a guided interaction between the mother and the fetus very early on in pregnancy to allow favorable pregnancy outcomes. Thus, it is essential to understand quantitatively if and when such a uniform distribution of embryos is established. Further, uncovering the physical and biological mechanisms that allow for such equal distribution of embryos, will improve our understanding of early pregnancy events and provide for novel targets for improving pregnancy success in case of infertility and artificial reproductive technologies as well as to develop non-hormonal therapies for contraception.
Cortical ChAT+neurons co-transmit acetylcholine and GABA in a target- and brain-region specific manner
Authors: Granger Adam J , Wang Wengang , Robertson Keiramarie , El-Rifai Mahmoud , Zanello Andrea , Bistrong Karina , Saunders Arpiar , Chow Brian , Nuñez Vicente , Garcia Miguel Turrero , Harwell Corey , Gu Chenghua , Sabatini Bernardo L 
Published: April 2020

AbstractThe cerebral cortex contains neurons that express choline acetyltransferase (ChAT) and are a potential local source of acetylcholine. However, the neurotransmitters released by cortical ChAT+neurons and their synaptic connectivity are unknown. We show that the nearly all cortical ChAT+neurons are specialized VIP+interneurons that release GABA strongly onto other inhibitory interneurons and acetylcholine sparsely onto layer 1 interneurons and other VIP+/ChAT+interneurons. This differential transmission of ACh and GABA based on the postsynaptic target neuron is reflected in VIP+/ChAT+interneuron pre-synaptic terminals, as quantitative molecular analysis shows that only a subset of these are specialized to release acetylcholine. In addition, we identify a separate, sparse population of non-VIP ChAT+neurons in the medial prefrontal cortex with a distinct developmental origin that robustly release acetylcholine in layer 1. These results demonstrate both cortex-region heterogeneity in cortical ChAT+interneurons and target-specific co-release of acetylcholine and GABA.
ATR inhibition enhances 5-fluorouracil sensitivity independent of non-homologous end-joining and homologous recombination repair pathway
Authors: Ito Soichiro S. , Nakagawa Yosuke , Matsubayashi Masaya , Sakaguchi Yoshihiko M. , Kobashigawa Shinko , Matsui Takeshi K. , Nanaura Hitoki , Nakanishi Mari , Kitayoshi Fumika , Kikuchi Sotaro , Kajihara Atsuhisa , Tamaki Shigehiro , Sugie Kazuma , Kashino Genro , Takahashi Akihisa , Hasegawa Masatoshi , Mori Eiichiro , Kirita Tadaaki 
Published: April 2020

ABSTRACTThe anticancer agent, 5-fluorouracil (5-FU), is typically applied in the treatment of various types of cancers because of its properties. Thought to be an inhibitor of the enzyme thymidylate synthase which plays a role in nucleotide synthesis, 5-FU has been found to induce single- and double-strand DNA breaks. The activation of ATR occurs as a reaction to UV- and chemotherapeutic drug-induced replication stress. In this study, we examined the effect of ATR inhibition on 5-FU sensitivity. Using western blotting, we found that 5-FU treatment led to the phosphorylation of ATR. Surviving fractions were remarkably decreased in 5-FU with ATR inhibitor (ATRi) compared to 5-FU with other major DNA repair kinases inhibitors. ATR inhibition enhanced induction of DNA double-strand breaks and apoptosis in 5-FU-treated cells. Using gene expression analysis, we found that 5-FU could induce the activation of intra-S checkpoint. Surprisingly,BRCA2-deficient cells were sensitive to 5-FU in the presence of ATRi. In addition, ATR inhibition enhanced the efficacy of 5-FU treatment, independent of non-homologous end-joining and homologous recombination repair pathways. Findings from the present study suggest ATR as a potential therapeutic target for 5-FU chemotherapy.
Greenhouse spatial effects detected in the barley (Hordeum vulgareL.) epigenome underlie stochasticity of DNA methylation
Authors: Konate Moumouni , Wilkinson Michael J. , Taylor Julian , Scott Eileen S. , Berger Bettina , Rodriguez Lopez Carlos Marcelino 
Published: April 2020

AbstractEnvironmental cues are known to alter the methylation profile of genomic DNA, and thereby change the expression of some genes. A proportion of such modifications may become adaptive by adjusting expression of stress response genes but others been shown to be highly stochastic, even under controlled conditions. The influence of environmental flux on plants adds an additional layer of complexity that has potential to confound attempts to interpret interactions between environment, methylome and plant form. We therefore adopt a positional and longitudinal approach to study progressive changes to barley DNA methylation patterns in response to salt exposure during development under greenhouse conditions. Methylation-Sensitive Amplified Polymorphism (MSAP) and phenotypic analyses of nine diverse barley varieties were grown in a randomized plot design, under two salt treatments (0 mM and 75 mM NaCl). Combining environmental, phenotypic and epigenetic data analyses, we show that at least part of the epigenetic variability, previously described as stochastic, is linked to environmental micro-variations during plant growth. Additionally, we show that differences in methylation increase with time of exposure to micro-variations in environment. We propose that subsequent epigenetic studies take into account microclimate-induced epigenetic variability.
Chloroplast chaperonin-mediated targeting of a thylakoid membrane protein
Authors: Klasek Laura , Inoue Kentaro , Theg Steven M. 
Published: April 2020

AbstractPost-translational protein targeting requires chaperone assistance to direct insertion-competent proteins to integration pathways. Chloroplasts integrate nearly all thylakoid transmembrane proteins post-translationally, but mechanisms in the stroma that assist their insertion remain largely undefined. Here, we investigated how the chloroplast chaperonin (Cpn60) facilitated the thylakoid integration of Plastidic type I signal peptidase 1 (Plsp1) using in vitro targeting assays. Cpn60 bound Plsp1 in the stroma. In isolated chloroplasts, the membrane integration of imported Plsp1 correlated with its dissociation from Cpn60. When the Plsp1 residues that interacted with Cpn60 were removed, Plsp1 did not integrate into the membrane. These results suggested Cpn60 was an intermediate in Plsp1’s thylakoid targeting. In isolated thylakoids, the integration of Plsp1 decreased if Cpn60 was present in excess of cpSecA1, the stromal motor of the cpSec1 translocon which inserts unfolded Plsp1 into the thylakoid. An excess of cpSecA1 favored integration. Introducing Cpn60’s obligate substrate RbcL displaced Cpn60-bound Plsp1; then, the released Plsp1 exhibited increased accessibility to cpSec1. These in vitro targeting experiments support a model in which Cpn60 captures and then releases insertion-competent Plsp1, while cpSecA1 recognizes free Plsp1 for integration. Thylakoid transmembrane proteins transiting the stroma can interact with Cpn60 to shield from the aqueous environment.One-sentence summaryThe chloroplast chaperonin captures and releases Plastidic type I signal peptidase 1 during its targeting to the thylakoid membrane.
Seipin and Nem1 establish discrete ER subdomains to initiate yeast lipid droplet biogenesis
Authors: Choudhary Vineet , Atab Ola El , Mizzon Giulia , Prinz William A. , Schneiter Roger 
Published: April 2020

ABSTRACTLipid droplets (LDs) are fat storage organelles that originate from the endoplasmic reticulum (ER). Relatively little is known about how sites of LD formation are selected, and which proteins/lipids are necessary for the process. Here, we show that LDs induced by the yeast triacylglycerol (TAG)-synthases Lro1 and Dga1 are formed at discrete ER subdomains defined by seipin (Fld1), and a regulator of diacylglycerol (DAG) production, Nem1. Fld1 and Nem1 colocalize to ER-LD contact sites. We find that Fld1 and Nem1 localize to ER subdomains independently of each other and of LDs, but both are required for the subdomains to recruit the TAG synthases and additional LD biogeneiss factors: Yft2, Pex30, Pet10, and Erg6. These subdomains become enriched in DAG. We conclude that Fld1 and Nem1 are both necessary to recruit proteins to ER subdomains where LD biogenesis occurs.
Identification of a novel efficient transcriptional activation domain from Chinese fir (Cunninghamia lanceolata)
Authors: Zhu Tengfei , Tang Wenyu , Chen Delan , Zheng Renhua , Li Jian , Su Jun 
Published: April 2020

AbstractActivation domains are used as critical components of artificial gene modification tools for genetic breeding. The high efficiency of the activation domain relies on the host plant. However, no activation domain has been identified that originates from Chinese fir (Cunninghamia lanceolate). In this study, a novel strong activator was identified from the whole Chinese fir cDNA library. This plant conserved activator was named TAC 3 (Transcriptional Activation domain from Chinese fir 3). C-terminal 70 amino acids of TAC (TAC3d) have a stronger ability than the commonly used strong activation domain of the virus protein VP16, or the strong plant activation domain, EDLL, in Chinese fir. Through Dual-luciferase assay, phenomic analysis and FT (Flowering Locus T [FT]) quantification, it was shown that, TAC3d can overcome the transcriptional repression of strong plant repressors (Flowering Locus C [FLC]) when fused to its C-terminal domain, thus inhibit the repression of FT expression. In conclusion, for the first time, an activation domain has been identified from Chinese fir. TAC3, which can be used for precise gene activation in Chinese fir in the future, and its function in the plant is more powerful than the commonly used strong activation domain (such as VP16 and EDLL).HighlightTAC3 is the first transcriptional activation domain identified from Chinese fir and its function is more powerful than some commonly used strong transcriptional activators (such as VP16 and EDLL)
Exceptional diversity and selection pressure on SARS-CoV and SARS-CoV-2 host receptor in bats compared to other mammals
Authors: Frank Hannah K. , Enard David , Boyd Scott D. 
Published: April 2020

AbstractPandemics originating from pathogen transmission between animals and humans highlight the broader need to understand how natural hosts have evolved in response to emerging human pathogens and which groups may be susceptible to infection. Here, we investigate angiotensin-converting enzyme 2 (ACE2), the host protein bound by SARS-CoV and SARS-CoV-2. We find that the ACE2 gene is under strong selection pressure in bats, the group in which the progenitors of SARS-CoV and SARS-CoV-2 are hypothesized to have evolved, particularly in residues that contact SARS-CoV and SARS-CoV-2. We detect positive selection in non-bat mammals in ACE2 but in a smaller proportion of branches than in bats, without enrichment of selection in residues that contact SARS-CoV or SARS-CoV-2. Additionally, we evaluate similarity between humans and other species in residues that contact SARS-CoV or SARS-CoV-2, revealing potential susceptible species but also highlighting the difficulties of predicting spillover events. This work increases our understanding of the relationship between mammals, particularly bats, and coronaviruses, and provides data that can be used in functional studies of how host proteins are bound by SARS-CoV and SARS-CoV-2 strains.
Melanocyte differentiation and epidermal pigmentation is regulated by polarity proteins
Authors: Knapp Sina K. , Iden Sandra 
Published: April 2020

ABSTRACTPigmentation serves various purposes such as protection, camouflage, or attraction. In the skin epidermis, melanocytes react to certain environmental signals with melanin production and release, thereby ensuring photo-protection. For this, melanocytes acquire a highly polarized and dendritic architecture that facilitates interactions with surrounding keratinocytes and melanin transfer. How the morphology and function of these neural crest-derived cells is regulated remains poorly understood. Here, using mouse genetics and primary cell cultures, we show that conserved proteins of the mammalian Par3-aPKC polarity complex are required for epidermal pigmentation. Melanocyte-specific deletion of Par3 in mice caused skin hypopigmentation, reduced expression of components of the melanin synthesis pathway, and altered dendritic morphology. Mechanistically, Par3 was necessary downstream of α-melanocyte stimulating hormone (α-MSH) to elicit melanin production. Strikingly, pharmacologic activation of MITF using a salt-inducible kinase inhibitor was sufficient to restore melanocyte differentiation and skin pigmentation in the absence of Par3. This data reveals a central role of polarity proteins in transmitting external pigment-inducing signals through the α-MSH/Mc1R/MITF ‘tanning pathway’, exposing unexpected links between polarity signaling and melanogenesis with new insights for pigment cell biology.
Topically delivered 22 nt siRNAs enhance RNAi silencing of endogenous genes in two species
Authors: Hendrix Bill , Zheng Wei , Bauer Matthew J. , Havecker Ericka R. , Mai Jennifer T. , Hoffer Paul H. , Sanders Rick , Eads Brian D. , Caruano-Yzermans Amy , Taylor Danielle N. , Hresko Chelly , Oakes Janette , Iandolino Alberto B. , Bennett Michael J. , Deikman Jill 
Published: April 2020

Abstract22 nt miRNAs or siRNAs have been shown to specifically induce production of transitive (secondary) siRNAs for targeted mRNAs. An abrasion method to deliver dsRNAs into leaf cells of intact plants was used to investigate the activities of 21 and 22 nt siRNAs in silencing genes inNicotiana benthamianaandAmaranthus cruentus. We confirmed that both 21 and 22 nt siRNAs were able to silence a green fluorescent protein (GFP) transgene in treated leaves ofN. benthamiana, but systemic silencing ofGFPoccurred only when the guide strand contained 22 nt. Silencing in the treated leaves ofN. benthamianawas demonstrated for 3 endogenous genes:magnesium cheletase subunit I(CHL-I),magnesium cheletase subunit H(CHL-H), andGUN4. However, systemic silencing of these endogenous genes was not observed. Very high levels of transitive siRNAs were produced forGFPin response to treatment with 22 nt siRNAs, but only low levels were produced in response to a 21 nt siRNA. The endogenous genes tested also had more transitive siRNAs produced in response to 22 nt siRNAs, but the response varied from weak (CHL-I) to strong (CHL-H). 22 nt siRNAs produced greater local silencing phenotypes than 21 nt siRNAs forGFP, CHL-HandGUN4inN. benthamiana. The special activity of 22 nt siRNAs in producing a greater local phenotype and induction of elevated levels of transitive siRNAs was also shown inA. cruentusfor theCHL-Hgene. These experiments suggest a functional role for transitive siRNAs in amplifying the RNAi response.
Antibiotics and the developing intestinal microbiome, metabolome and inflammatory environment: a randomized trial of preterm infants
Authors: Russell Jordan T. , Ruoss J. Lauren , de la Cruz Diomel , Li Nan , Bazacliu Catalina , Patton Laura , McKinley Kelley Lobean , Garrett Timothy J. , Polin Richard A. , Triplett Eric W. , Neu Josef 
Published: April 2020

AbstractAntibiotic use in neonates can have detrimental effects on the developing gut microbiome, increasing the risk of morbidity. A majority of preterm neonates receive antibiotics after birth without clear evidence to guide this practice. Here microbiome, metabolomic, and immune marker results from the Routine Early Antibiotic use in SymptOmatic preterm Neonates (REASON) study are presented. The REASON study is the first trial to randomize symptomatic preterm neonates to receive or not receive antibiotics in the first 48 hours after birth. Using 16S rRNA sequencing of stool samples collected longitudinally for 91 neonates, the effect of such antibiotic use on microbiome diversity is assessed. The results illustrate that type of nutrition shapes the early infant gut microbiome. By integrating data for the gut microbiome, stool metabolites, stool immune markers, and inferred metabolic pathways, an association was discovered betweenVeillonellaand the neurotransmitter gamma-aminobutyric acid (GABA). These results suggest early antibiotic use may impact the gut-brain axis with the potential for consequences in early life development, a finding that needs to be validated in a larger cohort.
The effects of temporal continuities of grasslands on the diversity and species composition of plants
Authors: Taiki Inoue , Yuki Yaida A. , Yuki Uehara , Koki Katsuhara R. , Jun Kawai , Keiko Takashima , Atushi Ushimaru , Tanaka Kenta 
Published: April 2020

AbstractSemi-natural grasslands are ecosystems rich in biodiversity. However, their decline has been reported worldwide, and identification of grasslands with high conservation priority is urgently required. Recently, an increasing number of studies have reported that past vegetation history affects current biological communities. To evaluate whether the temporal continuity of grasslands promotes biodiversity, and thus can be an indicator of conservation priority, we studied vascular plant communities in old (160– 1000s years) and new (52–70 years after deforestation) grasslands, as well as in forests, of Sugadaira Highland in central Japan. The number of plant species was highest in old grasslands, followed by new grasslands and forests. This pattern was much clearer in the number of grassland-dependent native and grassland-dependent endangered species, indicating the role of old grasslands as refugia for those species. The species composition differed between old and new grasslands. New grasslands had species compositions in between those of old grasslands and forests, suggesting that the plant community in new grasslands retains the influence of past forestation for more than 52 years after deforestation. Eleven indicator species were detected in old grasslands, but none in new grasslands, suggesting the uniqueness of the plant community in old grasslands. We conclude that the temporal continuity of grasslands increases plant diversity and can be an indicator of grasslands with high conservation priority.
Do government subsidies crowd out technological capabilities?
Authors: Chen Shuangying , Fu Feng , Xiang Tingting , Zeng Junli 
Published: April 2020

PurposeExtant research on the crowding-out effects of government subsidies on the positive role of firm innovation resources or activity remains limited. This paper aims to investigate the crowding-out effects of subsidies on the utilization of technological capabilities and also the contingency mechanisms of market-oriented economy based on the resource-based view (RBV), given the co-existence of the subsidies and technological capabilities for firm innovation in transitional economy.Design/methodology/approachThis paper used panel data of 115 Chinese high-tech firms from 2002 to 2010. Fixed-effects model was used to test several hypotheses.FindingsThis paper empirically demonstrates that the subsidies crowd out the utilization of firms’ technological capabilities for invention outcomes in the near-term. Furthermore, this paper finds that the crowding-out effects are weaker when firms have high export intensity or are located in provinces with high market-oriented systems.Research limitations/implicationsThe findings of this paper apply to Chinese firms. Future research could test their generalizability to different samples and other transitional economies.Practical implicationsThis paper highlights the crowding-out effects of the subsidies, revealing that high-tech firms should balance the direct effects and crowding-out effects of the subsidies.Originality/valueThis paper highlights the neglected interactions between the subsidies and technological capabilities based on RBV and provides a more nuanced understanding of the crowding-out effects of the subsidies in transitional economy.
Market reaction to the international acquisitions by Chinese firms
Authors: Lin Xinzhe , Li Yina , Wan Xiaolan , Wei Jiuchang 
Published: April 2020

PurposeThe purpose of this paper is to examine the effects of cross-border mergers and acquisitions (M&As) by firms in the emerging marketing on stock market cumulative abnormal returns (CARs). This research focuses on the acquiring firms in emerging markets and broadens the existing scope which highlights the M&As by firms in developed countries.Design/methodology/approachRegarding the controversial argument on the effect of cross-border M&As, the authors introduce a resource-based theory to explain the motivation of M&As by Chinese firms, conduct an event study analysis of 472 international acquisitions by Chinese firms from 2010 to 2015 and indicate cross-border M&As as a positive signal in the stock market.FindingsThe results reveal that cross-border M&As result in significantly positive CARs in a short term for the acquiring firms listed in mainland markets but not for that in the Hong Kong market. Furthermore, consistent with signaling theory and the investors’ heuristic thinking in decision-making, investors may adopt the technological innovation capability of the country where the target firms locate, and the acquiring firm’s preannouncement in shaping their positive judgment of the acquiring firm’s near future performance.Originality/valueThe authors distinguished the responses of the investors from the mainland and Hong Kong stock markets and investigated how the knowledge of the national innovation capability of the target firm and acquisition preannouncement influence the investors’ interpretation of the cross-border M&As as a market signal.