Integrated Smart Gas Tracking Device with Artificially Tailored Selectivity for Real-Time Monitoring Food Freshness.

The real-time monitoring of food freshness in refrigerators is of significant importance in detecting potential food spoiling and preventing serious health issues. One method that is commonly reported and has received substantial attention is the discrimination of food freshness via the tracking of volatile molecules. Nevertheless, the ambient environment of low temperature (normally below 4 °C) and high humidity (90% R.H.), as well as poor selectivity in sensing gas species remain the challenge. In this research, an integrated smart gas-tracking device is designed and fabricated. By applying pump voltage on the yttria-stabilized zirconia (YSZ) membrane, the oxygen concentration in the testing chamber can be manually tailored. Due to the working principle of the sensor following the mixed potential behavior, distinct differences in sensitivity and selectivity are observed for the sensor that operated at different oxygen concentrations. Typically, the sensor gives satisfactory selectivity to H2S, NH3, and C2H5OH at the oxygen concentrations of 10%, 30%, and 40%, respectively. In addition, an acceptable response/recovery rate (within 24 s) is also confirmed. Finally, a refrigerator prototype that includes the smart gas sensor is built, and satisfactory performance in discriminating food freshness status of fresh or semi-fresh is verified for the proposed refrigerator prototype. In conclusion, these aforementioned promising results suggest that the proposed integrated smart gas sensor could be a potential candidate for alarming food spoilage.

MicroRNA-136-5p protects cardiomyocytes from coronary microembolization through the inhibition of pyroptosis.

This study investigated how miR-136-5p partially affected cardiomyocyte pyroptosis in rats with coronary microembolization (CME). The cardiac function and structure of rats with CME were evaluated using echocardiography, hematoxylin and eosin staining, Masson staining, and troponin I level. Pyroptosis was induced by lipopolysaccharide (LPS) in isolated rat cardiomyocytes and evaluated by the expression of caspase-1, NOD-like receptor family pyrin domain-containing 3, interleukin-1ß, and gasdermin D-N. After cell transfection, the expression of Ataxin-1 like (ATXN1L), pyrin domain-containing 1 (PYDC1), and pyroptosis-related proteins was assessed. Dual-luciferase reporter and immunoprecipitation assays were used to verify the relationships among miR-136-5p, ATXN1L, and capicua (CIC). MiR-136-5p was under-expressed, whereas ATXN1L was overexpressed in rats with CME and in LPS-treated primary cardiomyocytes. MiR-136-5p targeted ATXN1L, and ATXN1L bound to CIC to suppress PYDC1 expression. MiR-136-5p overexpression suppressed pyroptosis by inhibiting the binding of ATXN1L with CIC and promoting PYDC1 expression, which was reversed by simultaneous elevation of ATXN1L. In conclusion, miR-136-5p suppressed pyroptosis by upregulating PYDC1 via ATXN1L/CIC axis, thereby attenuating cardiac damage caused by CME.

Long non-coding RNA CASC7 is associated with the pathogenesis of heart failure via modulating the expression of miR-30c.

MiRNAs can be used as promising diagnostic biomarkers of heart failure, while lncRNAs act as competing endogenous RNAs of miRNAs. In this study, we collected peripheral blood monocytes from subjects with or without HF to explore the association between certain lncRNAs, miRNAs and HF. Heart failure patients with preserved or reduced ejection fraction were recruited for investigation. ROC analysis was carried out to evaluate the diagnostic values of certain miRNAs and lncRNAs in HF. Luciferase assays were used to study the regulatory relationship between above miRNAs and lncRNAs. LncRNA overexpression was used to explore the effect of certain miRNAs in H9C2 cells. Expression of miR-30c was significantly decreased in the plasma and peripheral blood monocytes of patients suffering from heart failure, especially in these with reduced ejection fraction. On the contrary, the expression of lncRNA-CASC7 was remarkably increased in the plasma and peripheral blood monocytes of patients suffering from heart failure. Both miR-30c and lncRNA-CASC7 expression showed a promising efficiency as diagnostic biomarkers of heart failure. Luciferase assays indicated that miR-30c played an inhibitory role in lncRNA-CASC7 and IL-11 mRNA expression. Moreover, the overexpression of lncRNA-CASC7 suppressed the expression of miR-30c while evidently increasing the expression of IL-11 mRNA and protein in H9C2 cells. This study clarified the relationship among miR-30c, lncRNA-CASC7 and IL-11 expression and the risk of heart failure and showed that lncRNA-CASC7 is potentially involved in the pathogenesis of HF via modulating the expression of miR-30c.

Archaeal orthologs of Cdc45 and GINS form a stable complex that stimulates the helicase activity of MCM.

The regulated recruitment of Cdc45 and GINS is key to activating the eukaryotic MCM(2-7) replicative helicase. We demonstrate that the homohexameric archaeal MCM helicase associates with orthologs of GINS and Cdc45 in vivo and in vitro. Association of these factors with MCM robustly stimulates the MCM helicase activity. In contrast to the situation in eukaryotes, archaeal Cdc45 and GINS form an extremely stable complex before binding MCM. Further, the archaeal GINS•Cdc45 complex contains two copies of Cdc45. Our analyses give insight into the function and evolution of the conserved core of the archaeal/eukaryotic replisome.

The architecture of an Okazaki fragment-processing holoenzyme from the archaeon Sulfolobus solfataricus.

DNA replication on the lagging strand occurs via the synthesis and maturation of Okazaki fragments. In archaea and eukaryotes, the enzymatic activities required for this process are supplied by a replicative DNA polymerase, Flap endonuclease 1 (Fen1) and DNA ligase 1 (Lig1). These factors interact with the sliding clamp PCNA (proliferating cell nuclear antigen) providing a potential means of co-ordinating their sequential actions within a higher order assembly. In hyperthermophilic archaea of the Sulfolobus genus, PCNA is a defined heterotrimeric assembly and each subunit interacts preferentially with specific client proteins. We have exploited this inherent asymmetry to assemble a PCNA-polymerase-Fen1-ligase complex on DNA and have visualized it by electron microscopy. Our studies reveal the structural basis of co-occupancy of a single PCNA ring by the three distinct client proteins.

Inflammatory cytokines and their potential role in Sjogren's syndrome risk: insights from a mendelian randomization study.

AIM: This study aimed to investigate the causal impact of inflammatory cytokines on Sjogren's Syndrome (SS) and to identify potential biomarkers for SS clinical management using Mendelian Randomization (MR). MATERIALS AND METHODS: Leveraging GWAS summary data of inflammatory cytokines and SS, we executed the first two-sample MR analysis. Genetic variants from prior GWASs associated with circulating inflammatory cytokines served as instrumental variables (IVs). Data regarding cytokines were analyzed using the Olink Target-96 Inflammation panel, synthesizing data from 14,824 participants. GWAS summary statistics for SS were procured from the UK Biobank, focusing on samples of European ancestry. To discern the causal relationship between inflammatory cytokines and SS, several MR methodologies, including inverse variance weighted (IVW) and MR-Egger regression, were applied. RESULTS: After rigorous IV quality control, 91 cytokines were incorporated into the MR analysis. The IVW analysis identified 8 cytokines with a positive association to SS: Axin-1 (OR 2.56, 95% CI 1.07-6.10), T-cell surface glycoprotein CD5 (OR 1.81, 95% CI 1.08-3.02), CUDP1 (OR 1.61, 95% CI 1.00-2.58), CXCL10 (OR 1.92, 95% CI 1.25-2.95), IL-4 (OR 2.18, 95% CI 1.22-3.91), IL-7 (OR 2.35, 95% CI 1.27-4.33), MCP-2 (OR 1.27, 95% CI 1.05-1.54), and TNFRSF9 (OR 1.83, 95% CI 1.03-3.24), suggesting their potential in increasing SS risk. CONCLUSION: Our study conducted through MR, identified various inflammatory cytokines associated with SS risk, validating some previous research results and offering some new potential biomarkers for SS. However, these findings necessitate further research for validation and exploration of their precise role in the onset and progression of SS.

Retraction Notice to: miR-146a inhibits mitochondrial dysfunction and myocardial infarction by targeting cyclophilin D.

[This retracts the article DOI: 10.1016/j.omtn.2021.01.034.].

A pharmacokinetic study comparing the biosimilar HEC14028 and Dulaglutide (Trulicity®) in healthy Chinese subjects.

This study aimed to evaluate the pharmacokinetics (PKs), safety, and immunogenicity of the biosimilar HEC14028 compared to reference Trulicity® (dulaglutide) in healthy male Chinese subjects. This study was a single-center, randomized, open, single-dose, parallel-controlled comparative Phase I clinical trial, including a screening period of up to 14 days, a 17-day observation period after administration, and a 7-day safety follow-up period. A total of 68 healthy male subjects were randomly assigned (1:1) to the test group (HEC14028) and the reference group (dulaglutide) (single 0.75 mg abdominal subcutaneous dose). The primary objective was to evaluate the pharmacokinetic characteristics of HEC14028 and compare the pharmacokinetic similarities between HEC14028 and dulaglutide. The primary PK endpoints were maximum plasma concentration (Cmax) and area under the blood concentration-time curve from zero time to the estimated infinite time (AUC0-∞). The study results showed that HEC14028 and dulaglutide were pharmacokinetically equivalent: 90% confidence interval (CI) of Cmax and AUC0-∞ geometric mean ratios were 102.9%-122.0% and 97.1%-116.9%, respectively, which were both within the range of 80.00%-125.00%. No grade 3 or above treatment emergent adverse events (TEAEs), serious adverse events (SAEs), TEAEs leading to withdrawal from the trial, or TEAEs leading to death were reported in this study. Both HEC14028 and dulaglutide showed good and similar safety profiles, and no incremental immunogenicity was observed in subjects receiving HEC14028 and dulaglutide.

Analysis and comparison of blood metabolome of forest musk deer in musk secretion and non-secretion periods.

Musk is an important animal product, but the musk secretion mechanism of forest musk deer (Moschus berezovskii) is still unclear. The musk synthesis process in forest musk deer is extremely complex, and many raw materials are directly or indirectly derived from forest musk deer blood. In this study, metabolomics was used to analyze the blood of forest musk deer in secretory and non-secretory phases for the first time, aim at explaining the secretion mechanism from the perspective of blood metabolism. We found that P450-related, choline-related, axonal regeneration and other pathways and related metabolites were significantly enriched during the musk secretion of forest musk deer. These pathways and metabolites related to P450 and choline in blood may have important implications for the mechanism of musk secretion in forest musk deer, because blood components were closely related to musk components and could provide raw materials for musk synthesis in musk gland cells.

Lock/unlock mechanism of solvent-responsive binary polymer brushes: density functional theory approach.

A density functional theory (DFT) approach based on a weighted density approximation has been employed to study the perpendicular microphase separation of symmetric binary polymer brushes with weak incompatibility in explicit solvents with different selectivities. Characterized by the relation between the grand potential and vertical structures (including nonlayered and layered structures), a dry binary brush can be categorized as W-type or U-type according to whether the characteristic relation contains a structure that undergoes spontaneous symmetry breaking. A W-type brush can memorize the selectivity of the induced solvent in one of its two layered structures after the removal of solvent, which can be seen as a kind of lock state with the nonselective solvent used as its key to unlock. A U-type brush is lockless but can adapt to the environment without the nonselective solvent's triggering. Also, the boundary described in chain-length-incompatibility space is investigated by the DFT approach, which also verifies that the spontaneous symmetry breaking of the W-type brush originates from the molecular contributions to asymmetry, such as the enthalpic contribution of incompatibility and the entropic contribution of chain connectivity.

Crystallization and preliminary X-ray crystallographic analysis of the human CKIP-1 pleckstrin homology domain.

The casein kinase 2 interacting protein-1 (CKIP-1) is involved in many cellular functions, including apoptosis, signalling pathways, cell growth, cytoskeleton and bone formation. Its N-terminal pleckstrin homology (PH) domain is thought to play an important role in membrane localization and controls shuttling of CKIP-1 between the plasma membrane and nucleus. In this study, the human CKIP-1 PH domain was purified but problems were encountered with nucleic acid contamination. An S84D/S86D/S88D triple mutant designed to abolish nucleic acid binding was purified and successfully crystallized. Single crystals diffracted to 1.7 Šresolution and belonged to space group P43212 with unit-cell parameters a=53.0, b=53.0, c=113.8 Å, α=ß=γ=90.0°.

Metal-organic frameworks based surface-enhanced Raman spectroscopy technique for ultra-sensitive biomedical trace detection.

Metal-organic frameworks (MOFs) have attracted widespread interest due to their unique and unprecedented advantages in microstructures and properties. Besides, surface-enhanced Raman scattering (SERS) technology has also rapidly developed into a powerful fingerprint spectroscopic technique that can provide rapid, non-invasive, non-destructive, and ultra-sensitive detection, even down to single molecular level. Consequently, a considerable amount of researchers combined MOFs with the SERS technique to further improve the sensing performance and broaden the applications of SERS substrates. Herein, representative synthesis strategies of MOFs to fabricate SERS-active substrates are summarized and their applications in ultra-sensitive biomedical trace detection are also reviewed. Besides, relative barriers, advantages, disadvantages, future trends, and prospects are particularly discussed to give guidance to relevant researchers.

MiR-32-3p Regulates Myocardial Injury Induced by Microembolism and Microvascular Obstruction by Targeting RNF13 to Regulate the Stability of Atherosclerotic Plaques.

This study aimed to explore the molecular mechanism of myocardial protection. The effects of miR-32-3p and ring finger protein 13 (RNF13) on endoplasmic reticulum (ER) stress-induced apoptosis of A-10 cells and human umbilical vein endothelial cells (HUVEC) were detected using flow cytometry. The effects of miR-32-3p and phenylbutyric acid (PBA) on plaque instability and myocardial tissue injury in rats were investigated after establishment of arterial plaque model and embolization model and treatment with miR-32-3p-antagomir and PBA. RNF13, which was differentially expressed in myocardial infarction, was the direct target gene of miR-32-3p. MiR-32-3p inhibited RNF13 expression and targeted RNF13 to inhibit ER stress-induced cell apoptosis. Furthermore, inhibiting miR-32-3p expression induced arterial plaque instability by reducing survival, increasing pathological lesions in arterial tissue, up-regulating ER stress-related proteins, and regulating the expressions of apoptosis-related proteins in the model rats. However, PBA reversed the effects of miR-32-3p-antagomir on the model rats. MiR-32-3p regulates myocardial injury induced by micro-embolism and micro-vascular obstruction by targeting RNF13 to regulate the stability of atherosclerotic plaques.

LncRNA MALAT1 functions as a biomarker of no-reflow phenomenon in ST-segment elevation myocardial infarction patients receiving primary percutaneous coronary intervention.

MALAT1 was reported to sponge miR-30e, miR-126 and miR-155 in the pathogenesis of many diseases. Plasma miR-30e can indicate the risk of no-reflow during primary percutaneous coronary intervention (pPCI), while miR-126 can be used as a predictor of coronary slow flow phenomenon. In this study, we compared the diagnostic value of above genes in the prediction of no-reflow phenomenon in ST-segment elevation myocardial infarction (STEMI) subjects receiving pPCI. Quantitative real-time PCR, ELISA, Western blot and luciferase assays were performed to explore the regulatory relationship of MALAT1/miR-30e, MALAT1/miR-126, MALAT1/miR-155, miR-126/HPSE, and miR-155/EDN1. ROC analysis was carried out to evaluate the potential value of MALAT1, miRNAs and target genes in differentiating normal reflow and no-reflow in STEMI patients receiving pPCI. Elevated MALAT1, CRP, HPSE, and EDN1 expression and suppressed miR-30e, miR-155 and miR-126 expression was found in the plasma of STEMI patients receiving pPCI who were diagnosed with no-reflow phenomenon. ROC analysis showed that the expression of MALAT1, miR-30e, miR-126 and CRP could be used as predictive biomarkers to differentiate normal reflow and no-reflow in STEMI patients receiving pPCI. MALAT1 was found to suppress the expression of miR-30e, miR-126 and miR-155, and HPSE and EDN1 were respectively targeted by miR-126 and miR-155. This study demonstrated that MALAT1 could respectively sponge the expression of miR-30e, miR-126 and miR-155. And miR-30e, miR-126 and miR-155 respectively targeted CRP, HPSE and EDN1 negatively. Moreover, MALAT1 could function as an effective biomarker of no-reflow phenomenon in STEMI patients receiving pPCI.

Intelligent COVID-19 screening platform based on breath analysis.

The spread of coronavirus disease 2019 (COVID-19) results in an increasing incidence and mortality. The typical diagnosis technique for severe acute respiratory syndrome coronavirus 2 infection is reverse transcription polymerase chain reaction, which is relatively expensive, time-consuming, professional, and suffered from false-negative results. A reliable, non-invasive diagnosis method is in urgent need for the rapid screening of COVID-19 patients and controlling the epidemic. Here we constructed an intelligent system based on the volatile organic compound (VOC) biomarkers in human breath combined with machine learning models. The VOC profiles of 122 breath samples (65 of COVID-19 infections and 57 of controls) were identified with a portable gas chromatograph-mass spectrometer. Among them, eight VOCs exhibited significant differences (p< 0.001) between the COVID-19 and the control groups. The cross-validation algorithm optimized support vector machine (SVM) model was employed for the prediction of COVID-19 infection. The proposed SVM model performed a powerful capability in discriminating COVID-19 patients from healthy controls, with an accuracy of 97.3%, a sensitivity of 100%, a specificity of 94.1%, and a precision of 95.2%, and anF1 score of 97.6%. The SVM model was also compared with other common machine models, including artificial neural network,k-nearest neighbor, and logistic regression, and demonstrated obvious superiority in the prediction of COVID-19 infection. Furthermore, user-friendly software was developed based on the optimized SVM model. The developed intelligent platform based on breath analysis provides a new strategy for the point-of-care screening of COVID and shows great potential in clinical application.

Possible implication of miR-142-3p in coronary microembolization induced myocardial injury via ATXN1L/HDAC3/NOL3 axis.

This study aims to explore the mechanism underlying miR-142-3p regulating myocardial injury induced by coronary microembolization (CME) through ATXN1L. miR-142-3p overexpression or ATXN1L knockout adenovirus vectors were injected into rats before CME treatment. Cardiac functions were examined by echocardiography, and pathologies of myocardial tissues were assessed. Then, serum cTnI and IL-1ß contents and concentrations of IL-1ß and IL-18 in cell supernatant were measured. Immunofluorescence determined the localization of histone deacetylase 3 (HDAC3). The interaction between miR-142-3p and ATXN1L as well as the binding between HDAC3 and histone 3 (H3) was identified. The binding of ATXN1L and HDAC3 to NOL3 promoter was verified using ChIP. The levels of ATXN1L, NOL3, and miR-142-3p as well as apoptosis- and pyroptosis-related proteins and acetyl-histone 3 (ac-H3) were evaluated. CME treatment impaired the cardiac functions in rats and increased cTnI content. CME rats showed microinfarction foci in myocardial tissues. After CME treatment, miR-142-3p and NOL3 were modestly expressed while ATXN1L content was elevated, in addition to increases in apoptosis and pyroptosis. miR-142-3p overexpression or ATXN1L knockout alleviated CME-induced myocardial injury, cardiomyocyte apoptosis, and pyroptosis in myocardial tissues. miR-142-3p regulated ATXN1L expression in a targeted manner. In the cellular context, miR-142-3p overexpression attenuated apoptosis and pyroptosis in cardiomyocytes, which was partly counteracted by ATXN1L overexpression. ATXN1L functioned on cardiomyocytes by promoting deacetylation of H3 through HDAC3 and thus inhibited NOL3 expression. Inhibition of HDAC3 or overexpression of NOL3 ameliorated the promotive effects of ATXN1L on cardiomyocyte apoptosis and pyroptosis. In vivo and in vitro evidence in this study supported that miR-142-3p could attenuate CME-induced myocardial injury via ATXN1L/HDAC3/NOL3. HIGHLIGHTS: CME model witnessed aberrant expression of miR-142-3p, ATXN1L, and NOL3; miR-142-3p negatively regulated ATXN1L; miR-142-3p mediated CME-induced myocardial injury through ATXN1L; ATXN1L promoted deacetylation of H3 through HDAC3 and thus inhibited NOL3 expression; ATXN1L acted on cardiomyocyte apoptosis and pyroptosis through HDAC3/NOL3 axis.

Smartphone Case-Based Gas Sensing Platform for On-site Acetone Tracking.

Gas sensor-embedded smartphones would offer the opportunity of on-site tracking of gas molecules for various applications, for example, harmful air pollutant alarms or noninvasive assessment of health status. Nevertheless, high power consumption and difficulty in replacing malfunctioned sensors as well as limited space in the smartphone to host the sensor restrain the relevant advancements. In this article, we create a smartphone case-based sensing platform by integrating the functional units into a smartphone case, which performs a low detection limit of 117 ppb to acetone and high specificity. Particularly, dimming glass-regulated light fidelity (Li-Fi) communication is successfully developed, allowing the sensing platform to operate with relatively low power consumption (around 217 mW). Experimental proof on harmful gas sensing and potential clinic application is implemented with the sensing platform, demonstrating satisfactory sensing performance and acceptable health risk pre-warning accuracy (87%). Thus, the developed smartphone case-based sensing platform would be a good candidate for realizing harmful gas alarms and noninvasive assessment of health status.

HIF-1α-regulated lncRNA-TUG1 promotes mitochondrial dysfunction and pyroptosis by directly binding to FUS in myocardial infarction.

Myocardial infarction (MI) is a fatal heart disease that affects millions of lives worldwide each year. This study investigated the roles of HIF-1α/lncRNA-TUG1 in mitochondrial dysfunction and pyroptosis in MI. CCK-8, DHE, lactate dehydrogenase (LDH) assays, and JC-1 staining were performed to measure proliferation, reactive oxygen species (ROS), LDH leakage, and mitochondrial damage in hypoxia/reoxygenation (H/R)-treated cardiomyocytes. Enzyme-linked immunoassay (ELISA) and flow cytometry were used to detect LDH, creatine kinase (CK), and its isoenzyme (CK-MB) levels and caspase-1 activity. Chromatin immunoprecipitation (ChIP), luciferase assay, and RNA-immunoprecipitation (RIP) were used to assess the interaction between HIF-1α, TUG1, and FUS. Quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, and immunohistochemistry were used to measure HIF-1α, TUG1 and pyroptosis-related molecules. Hematoxylin and eosin (HE), 2,3,5-triphenyltetrazolium chloride (TTC), and terminal deoxynucleotidyl transferase dUTP risk end labelling (TUNEL) staining were employed to examine the morphology, infarction area, and myocardial injury in the MI mouse model. Mitochondrial dysfunction and pyroptosis were induced in H/R-treated cardiomyocytes, accompanied by an increase in the expression of HIF-α and TUG1. HIF-1α promoted TUG1 expression by directly binding to the TUG1 promoter. TUG1 silencing inhibited H/R-induced ROS production, mitochondrial injury and the expression of the pyroptosis-related proteins NLRP3, caspase-1 and GSDMD. Additionally, H/R elevated FUS levels in cardiomyocytes, which were directly inhibited by TUG1 silencing. Fused in sarcoma (FUS) overexpression reversed the effect of TUG1 silencing on mitochondrial damage and caspase-1 activation. However, the ROS inhibitor N-acetylcysteine (NAC) promoted the protective effect of TUG1 knockdown on H/R-induced cardiomyocyte damage. The in vivo MI model showed increased infarction, myocardial injury, ROS levels and pyroptosis, which were inhibited by TUG1 silencing. HIF-1α targeting upregulated TUG1 promotes mitochondrial damage and cardiomyocyte pyroptosis by combining with FUS, thereby promoting the occurrence of MI. HIF-1α/TUG1/FUS may serve as a potential treatment target for MI.

[Selective isolation and diversity of cold-adapted lipase-producing strains from permafrost soil at the terminus of a glacier in the Tianshan Mountains].

OBJECTIVE: The diversity of culturable lipase-producing bacterial strains from permafrost soils at the terminus of a glacier in the Tianshan Mountains was investigated. Isolation and molecular phylogenetic analysis were performed to expand our knowledge on diversity of psychrotrophic and psychrophilic bacteria. In addition, efforts were made focusing on screening for cold active lipases. METHODS: Lipase-producing bacterial strains were detected on tween 80 and olive oil plates, respectively. Identity and genetic diversity of strains isolated were determined by spatial 16S rRNA gene sequences and rep-PCR fingerprint. The physiological tests were carried out to determine the phonotypic differences between strains showing high similarity of 16S rRNA gene sequences. RESULTS: Of the total 17 bacterial stains exhibiting cold-adapted lipase activity, we found that only 8 stains were able to hydrolyze olive oil. Based on 16S rRNA gene sequences, the lipase-producing bacterial isolates fell in five phylogenetic groups: subclasses (, ( and ( of Proteobacteria, Actinobacteria, and the Cytophaga-Flexibacter-Bacteroides (CFB) phylum. Nearly 59% of the isolates were affiliated with the genus Pseudomonas. CONCLUSION: The results enrich our knowledge on the psychrotrophic bacterial diversity and biogeographic distribution of cold active lipases-producing bacteria in cold environments.

[Phylogenetic and physiological diversity of cold-adapted bacteria producing beta-galactosidase from permafrost sediments of the bottom layer of the Glacier No. 1 in the Tianshan Mountains].

OBJECTIVE: The purpose of this research is to isolate cold-adapted bacteria producing beta-galactosidase from permafrost sediments of the bottom layer of the Glacier No. 1 in the Tianshan Mountains, China. Physiological test and phylogenetic analysis were undertaken to expand our knowledge on diversity of psycrotrophic and psycrophlic bacteria. METHODS: By using lactose as the main carbon source and X-Gal as chromogenic agent in the medium, cold-adapted strains producing beta-galactosidase were detected. Taxonomic identity and genetic diversity of strains isolated were determined by spatial 16S rRNA gene sequences and rep-PCR fingerprint. In addition, we analyzed the phonotypic differences between strains showing high similarity of 16S rRNA gene sequences, including the optimum growth temperature, salt tolerance, ability to use carbon source and antibiotic resistance spectra. RESULTS: Of the total 90 cold-adapted bacterial strains isolated, we found 25 stains with beta-galactosidase activity, 76% of which were Gram-positive bacteria. According to growth temperature range, 80% of strains producing beta-galactosidase were identified as psychrophilic bacteria, 20% as psychrotrophs. Phylogeneticlly, the beta-galactosidase-producing bacterial isolates fell in four groups: subclasses alpha, beta and gamma of Proteobacteria, and Firmicutes phylum. CONCLUSION: The results enrich our knowledge on the phylogenetic and physiological diversity of cold-adapted strains producing beta-galactosidase in cold environments.