Spatial and temporal evolution of ecological vulnerability based on vulnerability scoring diagram model in Shennongjia, China.

Shennongjia is one of the most important ecological function areas and ecologically vulnerable zones in the world. With the rapid development of social economies, especially tourism, the ecological environment of Shennongjia has experienced profound changes. Exploring the characteristics and changing trends of ecological environment in Shennongjia will help to analyze the causes of the damage to the ecological environment, and build a vulnerability analysis framework with multi-scale, multi-element, multi-flow, and multi-circulation characteristics, which provides an effective research paradigm and analysis tool for the study of regional ecological vulnerability. With the support of RS and GIS technology, this study uses spatial principal component analysis (SPCA) and the vulnerability scoring diagram (VSD) model to comprehensively and quantitatively analyze the spatial and temporal evolution characteristics and driving forces of ecological vulnerability in Shennongjia from 1996 to 2018. The VSD model was selected to decompose the vulnerability into three components of "exposure-sensitivity-adaptation", and 16 indicators were selected to construct an ecological vulnerability evaluation system in Shennongjia, and the evaluation data were organized in a progressive and detailed way. (1) During the study period, the overall ecological vulnerability of Shennongjia is in a mild vulnerability level, exhibiting differentiation characteristics of high in the northeast and low in the southwest. High vulnerability zones are mainly distributed in the main towns and roads. (2) The risk of ecological vulnerability of the entire region presents the characteristics of continuous decline. (3) Land-use types, population density, and vegetation coverage are the main factors driving the evolution of ecological vulnerability. (4) A high level of coupling coordination exists between ecological vulnerability and landscape patterns. Analyses of the ecological vulnerability of Shennongjia shows that the entire region is in a mild vulnerability level. The extreme vulnerability risk of the ecological environment shows polarization. The evolution of ecological environment in Shennongjia is the result of the interaction between human activities and natural environment. This study offers an effective way to assess ecological vulnerability and provides some strategies and guidance for improving ecological security.

Remote sensing inversion and spatial variation of land surface temperature over mining areas of Jixi, Heilongjiang, China.

BACKGROUND: Jixi is a typical mining city in China that has undergone dramatic changes in its land-use pattern of mining areas over the development of its coal resources. The impacts of coal mining activities have greatly affected the regional land surface temperature and ecological system. METHODS: The Landsat 8 Operational Land Imager (OLI) data from 2015 and 2019 were used from the Jiguan, Didao, and Chengzihe District of Jixi in Heilongjiang, China as the study area. The calculations to determine the land-use classification, vegetation coverage, and land surface temperature (LST) were performed using ArcGIS10.5 and ENVI 5.3 software packages. A correlation analysis revealed the impact of land-use type, vegetation coverage, and coal mining activities on LSTs. RESULTS: The results show significant spatial differentiation in the LSTs of Jixi City. The LSTs for various land-use types were ranked from high to low as follows: mining land > construction land > grassland > cultivated land > forest land > water area. The LST was lower in areas with high vegetation coverage than in other areas. For every 0.1 increase in vegetation coverage, the LST is expected to drop by approximately 0.75 °C. An analysis of mining land patches indicates that the patch area of mining lands has a significant positive correlation with both the average and maximum patch temperatures. The average patch temperature shows a logarithmic increase with the growth of the patch area, and within 200,000 m2, the average patch temperature increases significantly. The maximum patch temperature shows a linear increase with the patch area growth, and for every 100,000 m2 increase in the patch area of mining lands, the maximum patch temperature increases by approximately 0.81 °C. The higher the average patch temperature of mining land, the higher the temperature in its buffer zone, and the greater its influence scope. This study provides a useful reference for exploring the warming effects caused by coal mining activities and the definition of its influence scope.

Comparison of the properties of neural stem cells of the hippocampus in the tree shrew and rat in vitro.

Neural stem cells (NSCs) are characterized by the ability of self­renewal and capacity to proliferate and produce new nervous tissue. NSCs are capable of differentiating to three lineages of neural cells, including neurons, oligodendrocytes and astrocytes. Furthermore, hippocampal NSCs transplantation can improve the neurological deficits associated with expression of cytokines. Therefore, to compare the properties of NSCs of tree shrews and rats in vitro, NSCs from tree shrews (tsNSCs) and rats f(rNSCs) were isolated. Nestin was used as a marker to identify the cultured NSCs. Neuronal nuclei protein and glial fibrillary acidic protein (GFAP) were utilized to demonstrate the differentiation of NSCs towards neurons and astrocytes, respectively, in vitro. Furthermore, the expression of neurotrophin 3 (NT3), brain­derived neurotrophic factor (BDNF), glial cell­derived neurotrophic factor (GDNF) and transforming growth factor (TGF)ß1 was also investigated in tsNSCs and rNSCs. The expression of all of the aforementioned proteins was detected using immunofluorescence methods. The results demonstrated that, after 5 days of culture, the average number of neurospheres in the cultured tsNSCs was significantly lower compared with rNSCs (P=0.0031). Additionally, compared with the rNSCs, tsNSCs exhibited an enhanced differentiation ability towards neurons. Furthermore, the expression of NT3 in the tsNSCs was higher compared with rNSCs (P<0.01), while the expression of BDNF was lower (P=0.045). However, no significant differences were observed in the expression level of GDNF and TGFß1 between rNSCs and tsNSCs. Therefore, these results indicate that tsNSCs exhibit specific characteristics that are different from rNSCs, which provides novel information for the understanding of NSCs obtained from tree shrews. Overall, the results of the current study provide evidence to support the increased application of tree shrews as models for diseases of the central nervous system.

[The Improvement in the Primary Culture of Alveolar Epithelial Type of Rats].

OBJECTIVES: To improve the method of culturing and obtain purified alveolar epithelial type1 (AT1) cells of SD rats. METHODS: 1 d newborn SD rats were applied for cell culture and brains were decapitated for lung tissues obtaining after respiratory cessation. Collagenase1and DNase1 were used to digest and isolate cells. Then, cells were put into the plate coated with type1 rat tail collagen and different adherence was used to purify cells. Meanwhile, culture medium replacement was conducted after 48 h. The growth status was observed under an inverted microscope. Immunofluorescence including specific marker AQP5, SPC, BSI, Vimentin were used to identify cells. RESULTS: 2 d after incubation, the cells began to adhere to plate. At day 4 and 6, cells began to proliferate and exhibited a shape of spindle, cube and polygon. 8 d after incubation, the character of proliferation reached the highest and the cell viability was (87±8)% and purification was (87±5)%. CONCLUSION: By modifying the methods of tissues harvest, isolation and culture, we can obtain AT 1 cells with high yield, good growth state and super purity.

Comparison of pathology, blood gas and biomarkers between two rat models of acute lung injury.

An ideal animal model to explore pathogenesis and prevention of acute lung injury (ALI) is essential. The present study aims to compare the difference in pathology, blood gas values and biomarkers of two acute lung injury rat models at different time intervals. In the experiment, rats were randomly divided into three groups: lipopolysaccharide (LPS) group, oleic acid (OA) group and control group. Changes of pathology, blood gas values and blood-air barrier biomarkers were analyzed at 15 minutes, 6 hours, 12 hours and 24 hours after injection. The results showed that the two models exhibited different features. Compared with the LPS rats, OA rats exhibited significantly severe pathological changes, lower arterial oxygen partial pressure (PaO2) value and higher level of injury biomarkers. However, LPS rats boasted greater lactic acid (LAC) level and more severe acidosis than OA rats. This study suggests that LPS-induced model has greater value in researches on microcirculation dysfunction and sepsis resulting from ALI, while OA-induced model has greater repeatability in area of gas exchanging after ALI. These events may provide a new theoretical evidence for the model establishment of ALI.

[Improving Primary Culture of Pulmonary Microvascular Endothelial Cells of Rats].

OBJECTIVES: To improve the culturing method of pulmonary microvascular endothelial cells (PMEVCs) of SD rats. METHODS: The culturing processes in regard to obtaining peripheral lung tissue, attaching tissue block,preparing medium and subculturing were modified.These included an injection of heparin sodium before anesthesia, abdominal bleeding, opening of chest when breathing stopped, improvement of operational details, reduction of pollution by adding penicillin and streptomycin, discard of tissues after 48 h of primary culturing, remove of fibroblasts by a second digestion, and identification of cells using a fluorescence microscope for binding with lectin from BSI (FITC-BSI).An inverted microscope was used to observe the morphological characteristics of PMEVCs. RESULTS: Purified PMEVCs were obtained,which displayed a polygon or short fusiform, exhibiting a typical cobblestone-like morphology. The morphology of PMVECs turned into swirling or long fusiform following subculture or changes in culture conditions. The results of FITC-BSI assay showed that more than 90% cells were stained with green fluorescence. CONCLUSIONS: Purified PMEVCs with a good growth state and subculture stability can be obtained using the modified method.

[Protective effect of ulinastatin on pulmonary function after cardiopulmonary bypass].

OBJECTIVE: To investigate the effects of Ulinastatin with different doses on pulmonary protection after cardiopulmonary bypass (CPB). METHODS: Ninety patients after CPB were brought into this study and divided into low doses Ulinastatin group (L group, n=30, 5 000 U/kg), high doses Ulinastatin group (H group, n=30, 20 000 U/kg) and control group (C group, n= 30), respectively. When the patients were transferred into ICU after CPB, Ulinastatin was given intravenously to those in L and H group, while saline was given in C group. Blood samples were harvested at the time before the treatments (T0) and 12 hours (T1), 24 hours (T2) after the treatments, for the measurements of arterial pressure of oxygen (PaO2), arterial pressure of carbon monoxide (PaCO2),difference of alveoli-arterial oxygen pressure (PO(2A), oxygenation index (Ol),and tumor necrosis factor-alpha (TNF-alpha) level. Pulmonary dynamic compliance (Cd), plat pressure (Pplat) and peak pressure (Ppeak) were determined at the time of To and wean (Tw). The durations of ventilation and intubation were recorded. RESULTS: At T0, the levels of PaO2, PaCO2, PO2A-a, OI and TNF-alpha in each group showed no significantly difference (P> 0. 05). At T1 and T2, the patients in H group had higher levels of PO2, PO2A-a. and OI, lower level of TNF-alpha, shorter duration of ventilation and intubation than the patients in other two groups(P<0. 05). The parameters in L group were better than those in C group, but the differences were not stastically significant (P>0. 05). There was no significantly difference in the levels of Cd, Pplat, and Ppeak at T0 and Tw between any two groups (P>0. 05). The intubation and ventilation time in H group were shorter than that in L and C group (P<0. 05). CONCLUSION: The application of Ulinastatin could achieve pulmonary protective effect after CPB, and it seems the effect could be better with high dose (20 000 U/kg) of Ulinastatin.

[A discussion about the tactics of mechanical ventilation for acute respiratory distress occurring in the first case of influenza A (H5N1) in Guizhou Province].

OBJECTIVE: To discuss the tactics of mechanical ventilation in a human severe case of influenza A (H5N1) complicated with acute respiratory distress syndrome (ARDS). METHODS: The data of the patient infected by the influenza A (H5N1) admitted to People's Hospital of Guizhou Province on January 15, 2009, were analyzed and summarized. RESULTS: The patient, a 29-year-old man, had been healthy in the past, but had exposed to the environment of bird flu before illness. The initial symptom was unremitting high fever, and then the clinical situation deteriorated progressively with occurrence of dyspnea. Pulmonary infiltrates were evident in the left lower lobe on January 19, and rapidly progressed to involve bilateral lungs presenting ARDS-like changes. Mechanical ventilation became the most important treatment among others. The ventilation mode was synchronized intermittent mandatory ventilation (SIMV)+ pressure support (PS) + positive end expiratory pressure (PEEP), following lung protective ventilatory strategies, with low tidal volume. The patient's condition improved day by day without developing multiple organ dysfunction. The patient fully recovered and was discharged on February 6. CONCLUSION: Early detection, early diagnosis, and finely effective intervention are to improve oxygenation by mechanical ventilation with low tidal volume and adequate PEEP are critical to reducing the mortality.

[Computer-aided molecular modeling and activity estimation for ligand screening with specific phage clone as the target].

OBJECTIVE: To investigate the interaction between tumor necrosis factor alpha (TNF alpha) mimotopes and TNF alpha-binding peptides screened from random phage display peptide library with TNF alpha mimotopes displayed on phage clone as the target, the computational docking program AutoDock (with confirmation calculations using Discover) was used to predict and analyze the binding modes of LLT-18 (TNF alpha binding peptide, sequence EHMALTYPFRPP) with TNF alpha, after which LCS-7 (TNF alpha mimic phage clone, displayed positive sequence c-RRPAQSG-c) was docked to LLT-18 manually. The binding between LLT-18 and TNF alpha or LCS-7 was stabilized predominantly through electrostatic interaction and H-bond formation. The Arg residues in TNF alpha or LCS-7 were important for their interaction with LLT-18. For LLT-18, the key amino acid residues were Glu1, His2, Met3 and Tyr7. These results suggest the feasibility of screening ligand to single epitope with specific phage clone as the target, and of predicting the interaction between small peptides by computer-aided molecular modeling.

Structure-based optimization of phenylbutyrate-derived histone deacetylase inhibitors.

Previously, we developed a strategy to develop a novel class of histone deacetylase (HDAC) inhibitors by tethering short-chain fatty acids with Zn(2+)-chelating motifs, which led to N-hydroxy-4-(4-phenylbutyryl-amino)benzamide (HTPB), a hydroxamate-tethered phenylbutyrate derivative with sub-micromolar potency in inhibiting HDAC activity and cancer cell proliferation. In this study, we carried out structure-based optimization of HTPB by using the framework generated by the structure of histone deacetylase-like protein (HDLP)-trichostatin A (TSA) complexes. Docking of HTPB into the HDLP binding domain suggested that the hydrophobic microenvironment encompassed by Phe-198 and Phe-200 could be exploited for structural optimization. This premise was corroborated by the greater potency of (S)-(+)-N-hydroxy-4-(3-methyl-2-phenylbutyrylamino)-benzamide [(S)-11] (IC(50) in HDAC inhibition, 16 nM), of which the isopropyl moiety was favorable in interacting with this hydrophobic motif. (S)-11 at concentrations as low as 0.1 microM was effective in causing histone hyperacetylation and p21(WAF/CIP1) overexpression and suppressing proliferation in cancer cells.

Effects of a fatty acid synthase inhibitor on adipocyte differentiation of mouse 3T3-L1 cells.

AIM: To investigate the influence of C75, a fatty acid synthase inhibitor, on adipocyte differentiation. METHODS: Mouse 3T3-L1 preadipocytes were induced to differentiation by insulin, isobutylmethylxanthine, and dexamethasone. Oil red O staining was performed and activity of glycerol-3-phosphate dehydrogenase (GPDH) was measured. The level of peroxisome proliferators-activated receptor gamma (PPARgamma) mRNA was assayed by semi-quantitative reverse transcription PCR. RESULTS: C75 blocked the adipogenic conversion in a dose-dependent manner and the inhibitory effects occurred both in the early phases (48 h) and in the latter phases (8 d) of the process. Treatment with C75 for 8 d induced more decrease in lipid content than 48 h (P<0.01). Treatment with C75 50 mg/L for 48 h or 8 d decreased GPDH activity by 52.8 % and 31.2 % of Vehicle, respectively. Treatment with C75 10-50 mg/L for 48 h or 8 d down-regulated PPARgamma mRNA expression compared with control (P<0.01). CONCLUSION: C75 blocked the adipocyte differentiation, which was related with down-regulation of PPARgamma mRNA.

A model of 3D-structure of H+, K+-ATPase catalytic subunit derived by homology modeling.

AIM: To build a model of 3D-structure of H(+), K(+)-ATPase catalytic subunit for theoretical study and anti-ulcer drug design. METHODS: The model was built on the basis of structural data from the Ca(2+)-ATPase. Structurally conserved regions were defined by amino acid sequence comparisons, optimum interconnecting loops were selected from the protein databank, and amino (N)- and carboxyl (C)-terminal ends were generated as random coil structures. Applying molecular mechanics method then minimized the model energy. Molecular dynamics technique was used to do further structural optimization. RESULTS: The model of 3D-structure of H(+), K(+)-ATPase was derived. The model is reasonable according to several validation criteria. There were ten transmembrane helices (TM1-TM10) in the model and inhibitor-binding site was identified on the TM5-8 riched negatively charged residues. CONCLUSION: The 3D-structure model from our study is informative to guide future molecular biology study about H(+), K(+)-ATPase and drug design based on database searching.

Molecular simulation of a single-chain antibody against AChE to explore molecular basis of inhibitory effect of 3F3 McAb on enzyme activity.

AIM: To explore the molecular basis of the inhibitory effect of 3F3, a monoclonal antibody against acetylcholinesterase (AChE), by computer-aided molecular simulation. METHODS: The single-chain 3F3 antibody (Sc3F3) was designed by joining VH and VL via a flexible linker (Gly4Ser)3. The amino acid sequence of the recombinant Sc3F3 was then subjected to computer-aided molecular modeling, and docking with the antigen molecule AChE to mimic the immunoactive interaction in a three-dimensional fashion. RESULTS: The modeled structure of Sc3F3 manifested the common features of a classical antibody. Both VH and VL were composed of two ?-sheets and connecting loops. The docking profile of the action between Sc3F3 with AChE demonstrated the formation of a stable structure. The van der Waals force played an important role suggesting that the complex was formed mainly via hydrophobic interactions between Sc3F3 and AChE molecules. CONCLUSION: The spatial structure of the complex of Sc3F3 and AChE showed that Sc3F3 overlaid the entrance of the active center gorge of AChE blocking the access of substrate.

[Study on Polyethylene Glycol Modified Porcine Hemoglobin Using Computer Modeling]

The structure analysis of porcine hemoglobin alphabeta dimer and the calculation of solvent accessible surface of the amino acids showed the epsilon-amino groups of the lysine are suitable for modification by polyethylene glycol (PEG). The modification of the lysine residues will not affect the carring oxygen capacity of Hb. Three types of linker have been designed to connect PEG and porcine hemoglobin. The lysines between porcine and bovine hemoglobin (pHb and bHb) are highly conserved, but the solvent accessible surface of conserved lysines are different. These suggested that the properties of homologous proteins are similar in pHb and bHb, but the characteristic derived from the homology analysis will be deviated from the actual status. The results of molecular dynamics simulation suggested that the chemical modified porcine hemoglobin would be no immunogenicity.