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1. chinaXiv:202006.00230 [pdf]

Tree ring based drought variability in Northwest Tajikistan since 1895 AD

YANG Meilin; YU Yang; ZHANG Haiyan; WANG Qian; GAN Miao; YU Ruide
Subjects: Geosciences >> History of Geosciences

Determining the mechanisms controlling the changes of wet and dry conditions will improve our understanding of climate change over the past hundred years, which is of great significance to the study of climate and environmental changes in the arid regions of Central Asia. Forest trees are ecologically significant in the local environment, and therefore the tree ring analysis can provide a clear record of regional historical climate. This study analyzed the correlation between the tree ring width chronology of Juniperus turkestanica Komarov and the standardized precipitation evapotranspiration index (SPEI) in Northwest Tajikistan, based on 56 tree ring samples collected from Shahristan in the Pamir region. Climate data including precipitation, temperature and the SPEI were downloaded from the Climate Research Unit (CRU) TS 4.00. The COFECHA program was used for cross-dating, and the ARSTAN program was used to remove the growth trend of the tree itself and the influence of non-climatic factors on the growth of the trees. A significant correlation was found between the radial growth of J. turkestanica trees and the monthly mean SPEI of February–April. The monthly mean SPEI sequence of February–April during the period of 1895–2016 was reconstructed, and the reconstruction equation explained 42.5% of the variance. During the past 122 a (1895–2016), the study area has experienced three wetter periods (precipitation above average): 1901–1919, 1945–1983 and 1995–2010, and four drier periods (precipitation below average): 1895–1900, 1920–1944, 1984–1994 and 2011–2016. The spatial correlation analysis revealed that the monthly mean SPEI reconstruction sequence of February–April could be used to characterize the large-scale dry-wet variations in Northwest Tajikistan during the period of 1895–2016. This study could provide comparative data for validating the projections of climate models and scientific basis for managing water resources in Tajikistan in the context of climate change.

submitted time 2020-06-22 From cooperative journals:《Journal of Arid Land》 Hits182Downloads89 Comment 0

2. chinaXiv:201605.01467 [pdf]

A parvalbumin-positive excitatory visual pathway to trigger fear responses in mice

Shang, Congping; Liu, Zhihui; Chen, Zijun; Shi, Yingchao; Wang, Qian; Liu, Su; Li, Dapeng; Cao, Peng; Shang, Congping; Chen, Zijun; Shi, Yingchao
Subjects: Biology >> Biophysics

The fear responses to environmental threats play a fundamental role in survival. Little is known about the neural circuits specifically processing threat-relevant sensory information in the mammalian brain. We identified parvalbumin-positive (PV+) excitatory projection neurons in mouse superior colliculus (SC) as a key neuronal subtype for detecting looming objects and triggering fear responses. These neurons, distributed predominantly in the superficial SC, divergently projected to different brain areas, including the parabigeminal nucleus (PBGN), an intermediate station leading to the amygdala. Activation of the PV+ SC-PBGN pathway triggered fear responses, induced conditioned aversion, and caused depression-related behaviors. Approximately 20% of mice subjected to the fear-conditioning paradigm developed a generalized fear memory.

submitted time 2016-05-12 Hits551Downloads336 Comment 0

3. chinaXiv:201605.01278 [pdf]

Improved Pharmacological and Structural Properties of HIV Fusion Inhibitor AP3 over Enfuvirtide: Highlighting Advantages of Artificial Peptide Strategy

Zhu, Xiaojie; Wang, Qian; Xu, Wei; Su, Shan; Sun, Zhiwu; Yu, Fei; Liu, Qi; Zhang, Xiaoyan; Xu, Jianqing; Lu, Lu; Jiang, Shibo; Zhu, Xiaojie; Wang, Qian; Xu, Wei; Su, Shan; Sun, Zhiwu; Yu, Fei; Liu, Qi; Zhang, Xiaoyan; Xu, Jianqing
Subjects: Biology >> Biophysics

Enfuvirtide (T20), is the first HIV fusion inhibitor approved for treatment of HIV/AIDS patients who fail to respond to the current antiretroviral drugs. However, its clinical application is limited because of short half-life, drug resistance and cross-reactivity with the preexisting antibodies in HIV-infected patients. Using an artificial peptide strategy, we designed a peptide with non-native protein sequence, AP3, which exhibited potent antiviral activity against a broad spectrum of HIV-1 strains, including those resistant to T20, and had remarkably longer in vivo half-life than T20. While the preexisting antibodies in HIV-infected patients significantly suppressed T20's antiviral activity, these antibodies neither recognized AP3, nor attenuated its anti-HIV-1 activity. Structurally different from T20, AP3 could fold into single-helix and interact with gp41 NHR. The two residues, Met and Thr, at the N-terminus of AP3 form a hook-like structure to stabilize interaction between AP3 and NHR helices. Therefore, AP3 has potential for further development as a new HIV fusion inhibitor with improved antiviral efficacy, resistance profile and pharmacological properties over enfuvirtide. Meanwhile, this study highlighted the advantages of artificially designed peptides, and confirmed that this strategy could be used in developing artificial peptide-based viral fusion inhibitors against HIV and other enveloped viruses.

submitted time 2016-05-11 Hits612Downloads339 Comment 0

4. chinaXiv:201605.01248 [pdf]

The Metabolic Regulator Histone Deacetylase 9 Contributes to Glucose Homeostasis Abnormality Induced by Hepatitis C Virus Infection

Chen, Jizheng; Guo, Min; Tang, Hong; Chen, Xinwen; Wang, Ning; Dong, Mei; Li, Zhong; Han, Xiao; Wang, Qian; Zhao, Yang; Zhuo, Zhiyong; Zhang, Chao; Chi, Xiumei; Pan, Yu; Jiang, Jing; Niu, Junqi; Yang, Dongliang
Subjects: Biology >> Biophysics

Class Ila histone deacetylases (HDACs), such as HDAC4, HDAC5, and HDAC7, provide critical mechanisms for regulating glucose homeostasis. Here we report that HDAC9, another class Ila HDAC, regulates hepatic gluconeogenesis via deacetylation of a Forkhead box 0 (FoxO) family transcription factor, FoxO1, together with HDAC3. Specifically, HDAC9 expression can be strongly induced upon hepatitis C virus (HCV) infection. HCV-induced HDAC9 upregulation enhances gluconeogenesis by promoting the expression of gluconeogenic genes, including phosphoenolpyruvate carboxykinase and glucose-6-phosphatase, indicating a major role for HDAC9 in the development of HCV-associated exaggerated gluconeogenic responses. Moreover, HDAC9 expression levels and gluconeogenic activities were elevated in livers from HCV-infected patients and persistent HCV-infected mice, emphasizing the clinical relevance of these results. Our results suggest HDAC9 is involved in glucose metabolism, HCV-induced abnormal glucose homeostasis, and type 2 diabetes.

submitted time 2016-05-11 Hits546Downloads315 Comment 0

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