Restriction Factor Research Articles

Replication competent HIV-guided CRISPR screen identifies antiviral factors including targets of the accessory protein Nef

Innate antiviral factors are essential for effective defense against viral pathogens. However, the identity of major restriction mechanisms remains elusive. Current approaches to discover antiviral factors usually focus on the initial steps of viral replication and are limited to a single round of infection. Here, we engineered libraries of >1500 replication-competent HIV-1 constructs each expressing a single gRNAs to target >500 cellular genes for virus-driven discovery of antiviral factors. Passaging in CD4+ T cells robustly enriched HIV-1 encoding sgRNAs against GRN, CIITA, EHMT2, CEACAM3, CC2D1B and RHOA by >50-fold. Using an HIV-1 library lacking the accessory nef gene, we identified IFI16 as a Nef target. Functional analyses in cell lines and primary CD4+ T cells support that the HIV-driven CRISPR screen identified restriction factors targeting virus entry, transcription, release and infectivity. Our HIV-guided CRISPR technique enables sensitive discovery of physiologically relevant cellular defense factors throughout the entire viral replication cycle.

Inhibition of caspase pathways limits CD4+ T cell loss and restores host anti-retroviral function in HIV-1 infected humanized mice with augmented lymphoid tissue.

The study of HIV infection and pathogenicity in physical reservoirs requires a biologically relevant model. The human immune system (HIS) mouse is an established model of HIV infection, but defects in immune tissue reconstitution remain a challenge for examining pathology in tissues. We utilized exogenous injection of the human recombinant FMS-like tyrosine kinase 3 ligand (rFLT-3L) into the hematopoietic stem cell (HSC) cord blood HIS mouse model to significantly expand the total area of lymph node (LN) and the number of circulating human T cells. The results enabled visualization and quantification of HIV infectivity, CD4 T cell depletion and other measures of pathogenesis in the secondary lymphoid tissues of the spleen and LN. Treatment with the Caspase-1/4 inhibitor VX-765 limited CD4+ T cell loss in the spleen and reduced viral load in both the spleen and axillary LN. In situ hybridization further demonstrated a decrease in viral RNA in both the spleen and LN. Transcriptomic analysis revealed that in vivo inhibition of caspase-1/4 led to an upregulation in host HIV restriction factors including SAMHD1 and APOBEC3A. These findings highlight the use of rFLT-3L to augment human immune system characteristics in HIS mice to support investigations of HIV pathogenesis and test host directed therapies, though further refinements are needed to further augment LN architecture and cellular populations. The results further provide in vivo evidence of the potential to target inflammasome pathways as an avenue of host-directed therapy to limit immune dysfunction and virus replication in tissue compartments of HIV+ persons.

Helicases DDX5 and DDX17 promote heterogeneity in HBV transcription termination in infected human hepatocytes

Transcription termination fine-tunes gene expression and contributes to the specification of RNA function in eukaryotic cells. Transcription termination of HBV is subject to the recognition of the canonical polyadenylation signal (cPAS) common to all viral transcripts. However, the regulation of this cPAS and its impact on viral gene expression and replication is currently unknown. To unravel the regulation of HBV transcript termination, we implemented a 3' RACE (rapid amplification of cDNA ends)-PCR assay coupled to single molecule sequencing both in invitro-infected hepatocytes and in chronically infected patients. The detection of a previously unidentified transcriptional readthrough indicated that the cPAS was not systematically recognized during HBV replication invitro and invivo. Gene expression downregulation experiments demonstrated a role for the RNA helicases DDX5 and DDX17 in promoting viral transcriptional readthrough, which was, in turn, associated with HBV RNA destabilization and decreased HBx protein expression. RNA and chromatin immunoprecipitation, together with mutation of the cPAS sequence, suggested a direct role of DDX5 and DDX17 in functionally linking cPAS recognition to transcriptional readthrough, HBV RNA stability and replication. Our findings identify DDX5 and DDX17 as crucial determinants of HBV transcriptional fidelity and as host restriction factors for HBV replication. HBV covalently closed circular (ccc)DNA degradation or functional inactivation remains the holy grail for the achievement of HBV cure. Transcriptional fidelity is a cornerstone in the regulation of gene expression. Here, we demonstrate that two helicases, DDX5 and DDX17, inhibit recognition of the HBV polyadenylation signal and thereby transcriptional termination, thus decreasing HBV RNA stability and acting as restriction factors for efficient cccDNA transcription and viral replication. The observation that DDX5 and DDX17 are downregulated in patients chronically infected with HBV suggests a role for these helicases in HBV persistence invivo. These results open new perspectives for researchers aiming at identifying new targets to neutralise cccDNA transcription.

Regulation of MHC II by OPTN, a novel regulator of MARCH1 via mTOR/AKT2/STAT3 pathway ameliorates severe outcomes during herpesvirus infection.

Abstract Protective immune responses elicited by primary activation of CD4+ T cells via dendritic cells is an essential requirement to evade herpesvirus infections. Optineurin (OPTN), a selective autophagy adaptor protein, is a crucial host restriction factor for herpes simplex virus (HSV) infection. We observed a significant reduction in the basal level of MHCII expression in OPTN–/– DCs accompanied by a concomitant decrease in CD4+ T cell counts in OPTN–/– mouse model. We hypothesize that abrogation of antigen presentation via MHCII in DCs weakens adaptive immune responses, leading to severe HSV1 infection. In this study, we elucidate the mechanism of OPTN-mediated down-regulation of MHCII via AKT/mTOR/STAT3 pathway. Mechanistically, OPTN induces activation of mTORC2 sequentially upregulating AKT2 which adversely affects the activation of mTORC1 and STAT3 protein. This could be attributed to the dynamic interplay between AKT1 and AKT2. Our findings provide novel insights into how the absence of OPTN downregulates AKT2 and triggers STAT3 activation. Furthermore, aberrant activation of STAT3 influences transcriptional activity of MARCH1(an E3 ubiquitin ligase) via IL10. MARCH1 mediates ubiquitination of MHCII resulting in the reduction of MHCII expression in OPTN–/– and AKT2–/– DCs. This study represents the first comprehensive delineation of the signaling pathway involved in the regulation of MHCII, shedding light on the intricate interplay between OPTN, AKT, mTOR, STAT3, and MARCH1.

Soil Ecological Stoichiometric Characteristics and Influencing Factors of Degraded Alpine Grassland in Northwest Sichuan

Alpine grasslands are important ecosystems providing a variety of ecosystem services. However, alpine grassland degradation poses significant threats impacting soil health, stabilization and soil ecosystem function. This study aims to investigate the soil ecological stoichiometric characteristics and influencing factors in alpine grasslands, to find the primary contributing factors in soil degradation process. Soil samples were collected from alpine grassland areas with varying degrees of degradation, including non-, lightly, moderately and severely degraded (ND, LD, MD, SD). Soil characteristics including soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), available nitrogen (AN), microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) were measured. The results revealed that soil TN, N:P ratios and C:P ratios were below the average level of China’s soil, while C:N ratio were above the average. With increasing aggravation of grassland degradation, SOC, TP, AN, MBN and MBC significantly decreased. Correlation were observed between SOC and C:N ratios as well as C:P ratios in alpine grassland with different degradation degrees (P < 0.05). The C:N ratios in degraded grasslands were lower than those in ND grasslands but higher than the average level of China’s soil. Additionally, the N:P and C:P ratios of LD and MD were significantly higher than those of ND, but lower than the China’s soil average level. In conclusion, soil degradation in alpine grasslands is associated with lower TN contents, higher C:N ratios, and lower N:P ratios, which can impact soil organic matter decomposition and act as plant growth restriction factor. This study provides comprehensive insights into the ecological stoichiometry of alpine grasslands, understanding these factors is essential for the sustainable management of alpine grasslands and restoration strategies for the ecosystem services.

Advances in hematopoietic stem cells ex vivo expansion associated with bone marrow niche.

Hematopoietic stem cells (HSCs) are an ideal source for the treatment of many hematological diseases and malignancies, as well as diseases of other systems, because of their two important features, self-renewal and multipotential differentiation, which have the ability to rebuild the blood system and immune system of the body. However, so far, the insufficient number of available HSCs, whether from bone marrow (BM), mobilized peripheral blood or umbilical cord blood, is still the main restricting factor for the clinical application. Therefore, strategies to expand HSCs numbers and maintain HSCs functions through ex vivo culture are urgently required. In this review, we outline the basic biology characteristics of HSCs, and focus on the regulatory factors in BM niche affecting the functions of HSCs. Then, we introduce several representative strategies used for HSCs from these three sources ex vivo expansion associated with BM niche. These findings have deepened our understanding of the mechanisms by which HSCs balance self-renewal and differentiation and provided a theoretical basis for the efficient clinical HSCs expansion.

From crack-prone to crack-free: Eliminating cracks in additively manufacturing of high-strength Mg2Si-modified Al-Mg-Si alloys

Large solidification ranges and coarse columnar grains in the additively manufacturing of Al-Mg-Si alloys are normally involved in hot cracks during solidification. In this work, we develop novel crack-free Al-Mg2Si alloys fabricated by laser powder-bed fusion (L-PBF). The results indicate that the eutectic Mg2Si phase possesses a strong ability to reduce crack susceptibility. It can enhance the grain growth restriction factor in the initial stage of solidification and promote eutectic filling in the terminal stage of solidification. The crack-free L-PBFed Al-xMg2Si alloys (x = 6 wt.%, 9 wt.%, and 12 wt.%) exhibit the combination of low crack susceptibility index (CSI), superior ability for liquid filling, and grain refinement. Particularly, the L-PBFed Al-9Mg2Si alloy shows improved mechanical properties (e.g. yield strength of 397 MPa and elongation of 7.3 %). However, the cracks are more likely to occur in the region near the columnar grain boundaries of the L-PBFed Al-3Mg2Si alloy with a large solidification range and low eutectic content for liquid filling. Correspondingly, the L-PBFed Al-3Mg2Si alloy shows poor bearing capacity of mechanical properties. The precise tuning of Mg2Si eutectic content can offer an innovative strategy for eliminating cracks in additively manufactured Al-Mg-Si alloy.

Deep removal of COS by carbon aerogel in natural gas: Performance and regeneration on K2O-Cu/CA adsorbent at room temperature

COS in natural gas is difficult to be effectively removed at room temperature. Catalytic hydrolysis is a promising method, however, the discrepancy of catalytic active site as well as deactivation factors are the restricting factors. In this paper, the CuO load and alkali metal modification was successfully prepared on carbon aerogel with more mesoporous structure(5 %K2O-Cu/CA). The doping of K could improve the pore structure of the sample and is more conducive to the storage of sulfate, obtaining good anti-poisoning properties. Meanwhile, the K load achieved enriched surface hydroxyl groups, which played an important role in COS conversion, and provided enough electronic electron transfers to accelerate the H2O dissociation, producing more hydroxyl groups. Then the adsorbed COS could be efficiently captured by the increasing number of weak basic sites at low temperature. Furthermore, after COS transformation the escaped H2S could be subsequently adsorbed on 5 %K2O-Cu/CA surface and converted to be S2- and SO42- on CuO surface. Finally, the adsorbent capacity and deactivation were studied, and the N2 regeneration method owns the higher sulfur capacity of 6.01 mg/g with a COS removal efficiency of 100 % for the first time.

Epstein-Barr virus-driven metabolic alterations contribute to the viral lytic reactivation and tumor progression in nasopharyngeal carcinoma.

Metabolic reprogramming induced by Epstein-Barr virus (EBV) often mirrors metabolic changes observed in cancer cells. Accumulating evidence suggests that lytic reactivation is crucial in EBV-associated oncogenesis. The aim of this study was to explore the role of metabolite changes in EBV-associated malignancies and viral life cycle control. We first revealed that EBV (LMP1) accelerates the secretion of the oncometabolite D-2HG, and serum D-2HG level is a potential diagnostic biomarker for NPC. EBV (LMP1)-driven metabolite changes disrupts the homeostasis of global DNA methylation and demethylation, which have a significantly inhibitory effect on active DNA demethylation and 5hmC content. We found that loss of 5hmC indicates a poor prognosis for NPC patients, and that 5hmC modification is a restriction factor of EBV reactivation. We confirmed a novel EBV reactivation inhibitor, α-KG, which inhibits the expression of EBV lytic genes with CpG-containing ZREs and the latent-lytic switch by enhancing 5hmC modification. Our results demonstrate a novel mechanism of which metabolite abnormality driven by EBV controls the viral lytic reactivation through epigenetic modification. This study presents a potential strategy for blocking EBV reactivation, and provides potential targets for the diagnosis and therapy of NPC.

ВОЗМОЖНЫЕ НАПРАВЛЕНИЯ И ОБЪЕКТЫ ПРИРОДНО-КУЛЬТУРНОГО НАСЛЕДИЯ В РАЗВИТИИ РЕКРЕАЦИОННЫХ ПОТОКОВ НА ТЕРРИТОРИИ КУРШСКОЙ КОСЫ И КУРШСКОГО ЗАЛИВА

The goal of this research is to identify and optimize possible directions and objects of culture heritage in the development of recreational flows on the Curonian spit and the Curonian bay territories. Based on the results of the 2023 field survey, including the interviews with locals and specialists as well as monographic analysis was used, possible and existing recreational objects were identified, their condition was assessed, providing and restrictive factors of development of recreation at objects were identified, possible touristic routes were determined. The Result Based Management method was used for complex analysis and comparative assessment of possible directions and objects of development of recreational flows in the territory of the Curonian Spit and the Curonian Lagoon. Its application in various geographical conditions allows to provide government bodies, investors and all parties concerned with operational and reliable insights about possibilities and priority of using natural and cultural heritage in the development of recreational flows. Such analysis at its deepening in spatial planning and design is capable of integrating data about ecosystem services, depletion/degradation, restoration of ecosystems, beneficiaries (income and benefits received) and other characteristics.

A STUDY ON REPRODUCTIVE LIFE OF THE BENGALEE HINDU FEMALES: A COMPARATIVE ANALYSIS

Reproduction is the process by which new individuals of a species are produced and the genetic materials are passed through generation after generation (Tortora, 2003). The existence of a species is maintained through the urge for the reproduction. Pearl (1939) accounted the urge for reproduction as basic attribute of all living organisms. The expressive form of this urge for the reproduction could be accounted as reproductivity or fertility. The urge for the reproduction in human could not be expressed in its full strength due to several restrictive factors work on it. Demographically observed fertility or infertility is the result of a well-defined number of both biological and behavioural factors, which serve to mediate the influence of culture, society, economic conditions, living standards, and other similar background determinants on individual reproductive behavior (Frank et al., 1994). The hedonistic attitude of human for the reduction of fertility would be described through the "Demographic Transition Model" (DTM) which defines the transition from high birth rates and high death rates to low birth rates and low death rates as part of the economic development of a country from a pre-industrial to an industrialized economy (Thompson, 1929). In the present study an attempt has been made to understand the current status of the reproductive life of the contemporary Bengalee females and the effect of demographic transition as well as fertility transition on the same. Materials of the present cross sectional study comprises with 200 adult married Bengalee females belonging to different caste group lived in a semi urban region of west Bengal. Mean age of the population was 32.63 ± 10.64. The result shows a remarkable decadal change in the reproductive life of the population. Age at menarche seems to follow the secular trend to being decreasing when comparing with a data (mean age 12.79 ± 41.37 and 13.41 ± 1.48 respectively). Comparison with a previous work revealed that the rate of literate women, employed women, the family income etc have been increased noticeable. The number of contraceptive used or adopt family planning families has also been increased remarkably in comparison with the earlier data (64.5 % and 56% respectively). Accordingly the rate of live birth has been decreased. The present study also differs from the age at marriage and marriage conception interval (MCI). Thus the present work revealed that the females (mothers) as well as the couples are more conscious about their reproductive life and adopt different family planning methods. Sharp decadal changes on their reproductive life could also be noticed which may be the ultimate result of the demographic transition.

Modeling of brain efflux: Constraints of brain surfaces

Fluid efflux from the brain plays an important role in solute waste clearance. Current experimental approaches provide little spatial information, and data collection is limited due to short duration or low frequency of sampling. One approach shows tracer efflux to be independent of molecular size, indicating bulk flow, yet also decelerating like simple membrane diffusion. In an apparent contradiction to this report, other studies point to tracer efflux acceleration. We here develop a one-dimensional advection-diffusion model to gain insight into brain efflux principles. The model is characterized by nine physiological constants and three efflux parameters for which we quantify prior uncertainty. Using Bayes' rule and the two efflux studies, we validate the model and calculate data-informed parameter distributions. The apparent contradictions in the efflux studies are resolved by brain surface boundaries being bottlenecks for efflux. To critically test the model, a custom MRI efflux assay measuring solute dispersion in tissue and release to cerebrospinal fluid was employed. The model passed the test with tissue bulk flow velocities in the range 60 to 190 [Formula: see text]m/h. Dimensional analysis identified three principal determinants of efflux, highlighting brain surfaces as a restricting factor for metabolite solute clearance.

The Inhibition of Gag-Pol Expression by the Restriction Factor Shiftless Is Dispensable for the Restriction of HIV-1 Infection.

The interferon-induced host cell protein Shiftless (SFL) inhibits -1 programmed ribosomal frameshifting (-1PRF) required for the expression of HIV-1 Gal-Pol and the formation of infectious HIV-1 particles. However, the specific regions in SFL required for antiviral activity and the mechanism by which SFL inhibits -1PRF remain unclear. Employing alanine scanning mutagenesis, we found that basic amino acids in the predicted zinc ribbon motif of SFL are essential for the suppression of Gag-Pol expression but dispensable for anti-HIV-1 activity. We have shown that SFL inhibits the expression of the murine leukemia virus (MLV) Gag-Pol polyprotein and the formation of infectious MLV particles, although Gag-Pol expression of MLV is independent of -1PRF but requires readthrough of a stop codon. These findings indicate that SFL might inhibit HIV-1 infection by more than one mechanism and that SFL might target programmed translational readthrough as well as -1PRF signals, both of which are regulated by mRNA secondary structure elements.

A Coupling Study of Agricultural Carbon Emission, Water Resources and Economic Development in Heilongjiang Province

Heilongjiang Province is a major agricultural province in China, and its agricultural water consumption will account for 88.6% of the province's water consumption in 2020.Based on the coupling effects of agricultural water resources, agricultural carbon emissions and agricultural economy, this paper calculates and finds the data of Heilongjiang Province from 2000 to 2019,and uses Kuznets model theory, literature reading method, systematic research method and geographical research as the theoretical basis. The negative problems of Heilongjiang Province's agriculture, such as weak level of sustainable development, unreasonable consumption of agricultural water resources, and poor sustainable and good development of environment and economy, are analyzed in depth. Finally, by analyzing the restrictive factors, the author puts forward the path and countermeasures of the corresponding coordinated economic development.

Assessment of the changes in growth, photosynthetic traits and gene expression in Cynodon dactylon against drought stress

Drought stress considered a key restrictive factor for a warm-season bermudagrass growth during summers in China. Genotypic variation against drought stress exists among bermudagrass (Cynodon sp.), but the selection of highly drought-tolerant germplasm is important for its growth in limited water regions and for future breeding. Our study aimed to investigate the most tolerant bermudagrass germplasm among thirteen, along latitude and longitudinal gradient under a well-watered and drought stress condition. Current study included high drought-resistant germplasm, “Tianshui” and “Linxiang”, and drought-sensitive cultivars; “Zhengzhou” and “Cixian” under drought treatments along longitude and latitudinal gradients, respectively. Under water deficit conditions, the tolerant genotypes showed over-expression of a dehydrin gene cdDHN4, antioxidant genes Cu/ZnSOD and APX which leads to higher antioxidant activities to scavenge the excessive reactive oxygen species and minimizing the membrane damage. It helps in maintenance of cell membrane permeability and osmotic adjustment by producing organic osmolytes. Proline an osmolyte has the ability to keep osmotic water potential and water use efficiency high via stomatal conductance and maintain transpiration rate. It leads to optimum CO2 assimilation rate, high chlorophyll contents for photosynthesis and elongation of leaf mesophyll, palisade and thick spongy cells. Consequently, it results in elongation of leaf length, stolon and internode length; plant height and deep rooting system. The CdDHN4 gene highly expressed in “Tianshui” and “Youxian”, Cu/ZnSOD gene in “Tianshui” and “Linxiang” and APX gene in “Shanxian” and “Linxiang”. The genotypes “Zhongshan” and “Xiaochang” showed no gene expression under water deficit conditions. Our results indicate that turfgrass show morphological modifications firstly when subjected to drought stress; however the gene expression is directly associated and crucial for drought tolerance in bermudagrass. Hence, current research has provided excellent germplasm of drought tolerant bermudagrass for physiological and molecular study and future breeding.

IJCM_77A: Predictors of fetal growth restriction in preterm birth

Background: Fetal growth restriction (FGR) is defined as fetuses whose estimated fetal weight or abdominal circumference is below the 10th percentile for gestational age. As Africa and South Asia account for 60-85% of these births, it becomes important to study the predictive factors of fetal growth restriction in preterm birth. Objective: To study the socio-demographic and obstetrics factors as predictive factors of fetal growth restriction in preterm birth. Methodology: This was a case-control study. The sample size was 10 (four mothers with a preterm baby with fetal growth restriction and six mothers with a preterm baby without fetal growth restriction). Through a proforma the socio-demographic, obstetric, neonatal details, and ultrasound readings were collected. The results were summarized using mean and standard deviations. Results: The average gestational age was 32.5 weeks in cases and 32.7 weeks in controls. In this study, oligohydramnios (0.011) and history of abortion (0.011) were seen more in mothers with fgr in preterm birth compared to those in mothers with non-fgr in preterm birth babies. Conclusion: Oligohydramnios and history of abortion were the predictors of fetal growth restriction in preterm birth.

Research on the Restrictive Factors and Strategies for Improving the Teaching Ability of University Teachers under the Background of Education Digitization

Education digitization deeply integrates modern information technology with education, innovates the traditional teaching mode of universities, and makes higher education glow with new vitality. At present, the digital transformation of higher education has become a research focus of higher education reform. Therefore, the digital teaching ability of university teachers has become an indispensable force. It is not only conducive to the construction of college teachers but also conducive to the improvement of university teaching quality, which is a key factor related to the quality of higher talent training in the new era. Therefore, whether university teachers can adapt to the development of digitalization and how to improve their digitalized teaching ability are worthy of attention. Based on this research background, this paper tries to summarize the new requirements of digital transformation of education for teachers' teaching ability by reading relevant literature of the Ministry of Education and taking TPACK theory as guidance. Then, combined with the existing investigation and research results, using case analysis and comparative research, this paper summarizes and analyzes the constraints that affect the development of teachers' abilities from both internal and external aspects of teachers. Finally, based on the analysis of the constraints, suggestions are put forward from the perspectives of teachers' teaching cognition, teaching behavior, school training organization, evaluation system, and digital construction.

How to standardize the diagnostic approach to pituitary neuroendocrine tumors.

Pituitary tumors present heterogeneous biochemical, clinico-radiological, and histological features. Although histologically benign, a non-negligible number of cases present an unpredictable aggressive behavior with local invasiveness, partial/complete resistance to treatment and/or recurrence after surgery, and, rarely, metastasize, overall leading to a significant increase of morbidity, and, thus, requiring skilled multidisciplinary management in referral Centers. Histopathological diagnosis is essential to stratify cancer patient risk and uniform follow-up among Centers. Classification of pituitary neoplasia is continuously evolving in relation to the increased knowledge of mechanisms underlying adenohypophyseal cell tumorigenesis, and the attempts of combining clinico-radiological, biochemical, intraoperative, histological, and molecular elements, with the aim of identifying aggressive forms through. An integrated standardized histopathological report has been proposed in 2019 by the European Pituitary Pathology Group, based on the indications of the 2017 WHO classification of pituitary tumors. The last edition of the WHO Classification of Central Nervous System Tumors and of Endocrine and Neuroendocrine Tumors brought substantial novelties: 1) the replacement of the term "adenoma" with "Pituitary Neuroendocrine Tumor" (PitNET), and of "carcinoma" with "metastatic PitNET," and the consequent ICD-11 recoding from benign to malignant disease; and 2) the pivotal role of lineage restricted pituitary transcription factors for histological typing and subtyping. However, this approach does not reflect the spectrum of tumor phenotypes based on hormone secretion, nor include molecular features. Efforts of interdisciplinary groups of pituitary experts should be strongly encouraged to better understand factors involved in PitNETs evolution and, consequently, standardize diagnosis and reporting based on the most recent knowledges, essential to stratify cancer patient risk and uniform follow-up among centers.

Predicting Quercus gilva distribution dynamics and its response to climate change induced by GHGs emission through MaxEnt modeling

Quercus gilva, an evergreen tree species in Quercus section Cyclobalanopsis, is an ecologically and economically valuable species in subtropical regions of East Asia. Predicting the impact of climate change on potential distribution of Q. gilva can provide a scientific basis for the conservation and utilization of its genetic resources, as well as for afforestation. In this study, 74 distribution records of Q. gilva and nine climate variables were obtained after data collection and processing. Current climate data downloaded from WorldClim and future climate data predicted by four future climate scenarios (2040s SSP1-2.6, 2040s SSP5-8.5, 2060s SSP1-2.6, and 2060s SSP5-8.5) mainly based on greenhouse gases emissions of distribution sites were used in MaxEnt model with optimized parameters to predict distribution dynamics of Q. gilva and its response to climate change. The results showed that the predicted current distribution was consistent with natural distribution of Q. gilva, which was mainly located in Hunan, Jiangxi, Zhejiang, Fujian, Guizhou, and Taiwan provinces of China, as well as Japan and Jeju Island of South Korea. Under current climate conditions, precipitation factors played a more significant role than temperature factors on distribution of Q. gilva, and precipitation of driest quarter (BIO17) is the most important restriction factor for its current distribution (contribution rate of 57.35%). Under future climate conditions, mean temperature of driest quarter (BIO9) was the essential climate factor affecting future change in potential distribution of Q. gilva. As the degree of climatic anomaly increased in the future, the total area of predicted distribution of Q. gilva showed a shrinking trend (decreased by 12.24%–45.21%) and Q. gilva would migrate to high altitudes and latitudes. The research results illustrated potential distribution range and suitable climate conditions of Q. gilva, which can provide essential theoretical references for the conservation, development, and utilization of Q. gilva and other related species.

Вплив факторів ризику на формування затримки росту плода

Fetal growth retardation is defined as the condition of a fetus whose weight is less than 10% of the gestational weight age, that is, the fetus does not reach its genetic growth potential. Aim - to determine the risk factors contributing to the formation of fetal growth retardation. Materials and methods. A retrospective study of medical documentation of 110 patients (main group) with a confirmed fetal growth restriction and 70 pregnant women of the control group, searching risk factors for fetal growth restriction. Results. The frequency of abnormalities of the umbilical cord and placenta was 24.5% in the main group against 4% in the control group. Extragenital diseases occurred in 74.5% versus 20% in the control group. In addition, uterine malformations (6.3% in the main and 2% in the control groups), low weight before pregnancy 41.8% in the main and 20% in the control group. Heavy bleeding in the I and II trimesters of pregnancy - 10% in the main group versus 2% in the control group, abnormal biochemical markers of I and II screening - 56.3% in the main group versus 30% in the control group. Conclusions. Insufficient growth of the fetus is a multifactorial pathology, among the leading pathogenetic factors of extragenital diseases, uterine malformations, additional reproductive technologies, low maternal weight before pregnancy. Except moreover, risk factors for fetal growth retardation are previous births a child with a low weight, the interval between pregnancies less than 18 months and the mother's age is over 35 years old. 13.6% of pregnant women with insufficient fetal growth had more than 3 factors risk (in the control group - 1.4%), however, more than a third of patients who had such a pregnancy complication (35.4%) had none of the listed risk factors, which prompts further research into pathogenesis. The research was carried out in accordance with the principles of the Declaration of Helsinki. The research protocol was approved by the Local Ethics Committee of all institutions mentioned in the work. Informed consent of the children's parents was obtained for the research. The authors declare no conflict of interest.