Impact of extreme pre-monsoon drought on xylogenesis and intra-annual radial increments of two tree species in a tropical montane evergreen broad-leaved forest, southwest China.

Tropical montane evergreen broad-leaved forests cover the majority of forest areas and have high carbon storage in Xishuangbanna, southwest China. However, stem radial growth dynamics and their correlations with climate factors have never been analyzed in this forest type. By combining bi-weekly microcoring and high-resolution dendrometer measurements, we monitored xylogenesis and stem radius variations of the deciduous species Betula alnoides Buch.-Ham. ex D. Don and the evergreen species Schima wallichii (DC.) Korth. We analyzed the relationships between weekly climate variables prior to sampling and the enlarging zone width or wall-thickening zone width, as well as weekly radial increments and climate factors during two consecutive years (2020 to 2021) showing contrasting hydrothermal conditions in the pre-monsoon season. In the year 2020, which was characterized by a warmer and drier pre-monsoon season, the onset of xylogenesis and radial increments of B. alnoides and S. wallichii were delayed by three months and one month, respectively, compared with the year 2021. In 2020, xylem formation and radial increments were significantly reduced for B. alnoides, but not for S. wallichii. The thickness of enlarging zone and wall-thickening zone in S. wallichii were positively correlated with relative humidity, and minimum and mean air temperature, but were negatively correlated with vapor pressure deficit during 2020 to 2021. The radial increments of both species showed significant positive correlations with precipitation and relative humidity, and negative correlations with vapor pressure deficit and maximum air temperature during two years. Our findings reveal that drier pre-monsoon conditions strongly delay growth initiation and reduce stem radial growth, providing deep insights to understand tree growth and carbon sequestration potential in tropical forests under a predicted increase in frequent drought events.

Adolescent administration of ketamine impairs excitatory synapse formation onto parvalbumin-positive GABAergic interneurons in mouse prefrontal cortex.

Ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, induces deficits in cognition and information processing following chronic abuse. Adolescent ketamine misuse represents a significant global public health issue; however, the neurodevelopmental mechanisms underlying this phenomenon remain largely elusive. This study investigated the long-term effects of sub-chronic ketamine (Ket) administration on the medial prefrontal cortex (mPFC) and associated behaviors. In this study, Ket administration during early adolescence displayed a reduced density of excitatory synapses on parvalbumin (PV) neurons persisting into adulthood. However, the synaptic development of excitatory pyramidal neurons was not affected by ketamine administration. Furthermore, the adult Ket group exhibited hyperexcitability and impaired socialization and working memory compared to the saline (Sal) administration group. These results strongly suggest that sub-chronic ketamine administration during adolescence results in functional deficits that persist into adulthood. Bioinformatic analysis indicated that the gene co-expression module1 (M1) decreased expression after ketamine exposure, which is crucial for synapse development in inhibitory neurons during adolescence. Collectively, these findings demonstrate that sub-chronic ketamine administration irreversibly impairs synaptic development, offering insights into potential new therapeutic strategies.

Ischemic stroke protected by ISO-1 inhibition of apoptosis via mitochondrial pathway.

Macrophage migration inhibitory factor (MIF) is an immune mediator associated with inflammation, which is upregulated after ischemia in brain tissue. ISO-1 is a potent inhibitor of MIF tautomerase and can protect neurons by reducing the permeability of blood brain barrier (BBB). In this study, we investigated the role of ISO-1 in cerebral ischemia/reperfusion injury by establishing a model of middle cerebral artery occlusion/reperfusion in rats. Rats were randomly divided into four groups: the sham operation group, the ISO-1group, the cerebral I/R group, and the ISO-1 + I/R group. We assessed the degree of neurological deficit in each group and measured the volume of cerebral infarction. We detected the expression of MIF in the core necrotic area and penumbra. We detected the expression of apoptosis-related proteins, apoptosis-inducing factor (AIF), endonuclease G (EndoG) and cytochrome c oxidase-IV (COX-IV) in the ischemic penumbra region. The results showed that MIF was expressed in the ischemic penumbra, while the injection of ISO-1 was able to alleviate neurological damage and reduce the infarction volume. In the cerebral ischemic penumbra region, ISO-1 could reduce the expression of Bax and Caspase3 and inhibit the displacement of AIF and EndoG to the nucleus simultaneously. Besides, ISO-1 also exhibited the ability to reduce apoptosis. In summary, ISO-1 may inhibit neuronal apoptosis through the endogenous mitochondrial pathway and reduce the injury of brain I/R after ischemic stroke.

[Intra-annual radial growth of Garuga floribunda in tropical seasonal rain forest and its response to environmental factors in Xishuangbanna, Southwest China]. / çƒ­å¸¦å­£èŠ‚é›¨æž—å¤šèŠ±ç™½å¤´æ ‘å¹´å† å¾„å‘ç”Ÿé•¿åŠ¨æ€åŠå ¶å¯¹çŽ¯å¢ƒå› å­çš„å“åº”.

We examined the seasonal growth dynamics of a deciduous tree species Garuga floribunda in the tropical seasonal rain forest in Xishuangbanna and monitored the stem radial growth with both high resolution dendrometer and microcoring methods. Combining with the monitoring of non-structural carbohydrates (NSCs) in stem and environmental factors, we analyzed the eco-physiological drivers underlying the seasonal cambial activity and radial growth dynamics. The results of high reso-lution dendrometer method showed that the growth of G. floribunda began at the end of May (day of year, DOY: 149.3±7.2) and ended at the end of August (DOY: 241.0±14.7) in 2020, the annual total radial growth was 3.12 mm, and the maximum growth rate was 0.04 mm·d-1. Based on the microcoring methods, we found that xylem cell enlarging started from March 9th (69.2±6.2) and cell wall thickening ended on September 19th (DOY: 262.8±2.8). The cumulative xylem radial growth was 1.76 mm, and the maximum growth rate was 0.009 mm·d-1. The daily radial growth rate of G. floribunda was significantly and positively correlated with precipitation, relative humidity, daily minimum air temperature, soil moisture and temperature at the depth of 20 cm, and was negatively correlated with daily maximum air temperature, vapor pressure deficit, maximum wind speed, and water vapor pressure. The starch and soluble sugar contents in the sapwood of G. floribunda were relatively higher before the growing season. The starch content was lowest in the end of March, while the content of soluble sugars was lowest in middle of May. At the end of the growing season, the contents of starch and soluble sugar in G. floribunda peaked in the middle of October and the end of December, respectively.

Study on 3'-UTR length polymorphism in peripheral blood mononuclear cells of uremia patient.

OBJECTIVE: The objective of this study was to measure the 3'-untranslated region (3'-UTR) polymorphism lengths in peripheral blood mononuclear cells (PBMCs) from uremia patients. METHOD: We sequenced the alternative polyadenylation sites in the 3'-UTR of PBMCs from 10 uremic patients and 10 healthy people to detect different gene expression levels between uremia patients and healthy controls. Quantitative reverse transcription polymerase chain reaction was used as validation. RESULT: Compared with the healthy control group, 691 genes in uremic patients had significantly different 3'-UTR lengths. Of these genes, 475 genes showed shortened 3'-UTRs, and the 3'-UTRs of 216 genes were lengthened. The verification results matched the original sequencing results. CONCLUSION: There were significant differences in 3'-UTR lengths between uremic patients and healthy controls, and analysis of the differential genes may contribute to the understanding of uremia pathogenesis.

CCDC40 mutation as a cause of primary ciliary dyskinesia: a case report and review of literature.

BACKGROUND AND AIMS: Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous disorder. Genetic defects affecting motility of cilia and flagella cause chronic destructive airway disease, situs inversus and, frequently, male infertility in PCD. To date, although several genes have been implicated in PCD, the genetic bases of most cases of PCD remain elusive. METHODS: By applying a whole-exome sequencing strategy, we reported a case of PCD carrying a novel mutant alleles in CCDC40 gene, and did literature review. RESULTS: A 36-year-old nonsmoking Chinese man suffered from chronic cough since childhood and an 8-year history of primary infertility. Lung biopsy showed respiratory bronchiolitis. Chest images showed bronchiectasis and situs inversus. Semen analysis showed high sperm counts and poor sperm motility. Transmission electron microscopy (TEM) of cilia cross-sections showed ultrastructural defects, including inner dynein arms (IDA) defect and axonemal disorganization. To identify gene mutations that cause PCD, we performed exome sequencing to analyze genome of this patient, and discovered a previously uncharacterized mutant alleles (NM_001243342.1:c.2609G>A; p. R870H) in CCDC40 gene. In addition, we summarize the PCD disease-causing genes and CCDC40 mutant sites based on current literature. CONCLUSIONS: We identified a novel mutant alleles in CCDC40 gene, which altered the protein sequence and resulted in the ultrastructural defects in the microtubule structure of cilia. Thereby, these defects lead to the patient with bronchiectasis, bronchiolitis and infertility.

Composition and variation analysis of the TCR ß-chain CDR3 repertoire in systemic lupus erythematosus using high-throughput sequencing.

The ability of T lymphocytes to mount an immune response against a diverse array of pathogens is primarily conveyed by the amino acid (aa) sequence of the hypervariable complementarity-determining region 3 (CDR3) segments of the T cell receptor (TCR). In this study, we used a combination of multiplex-PCR, Illumina sequencing and IMGT/HighV-QUEST for a standardized analysis of the characteristics and polymorphisms of the T-cell receptor BV complementarity-determining region 3 (TCR BV CDR3) gene in peripheral blood mononuclear cells (PBMCs) from SLE patients and healthy donors (NC). We found the distributions of CDR3, VD indel, and DJ indel lengths to be comparable between the SLE and NC groups. The degree of clonal expansion in the SLE group was significantly greater than in the NC group, and the expression levels of 10 TRßV segments and 6 TRßJ segments were also significantly different in the SLE group. Regarding public T cell responses, 3CDR3 DNA sequences and 4 aa sequences were shared by all SLE patients and may serve as biomarkers for SLE disease risk, diagnosis and/or prognosis.