Influence of blood glucose fluctuations on chemotherapy efficacy and safety in type 2 diabetes mellitus patients complicated with lung carcinoma.

BACKGROUND: Patients with type 2 diabetes mellitus (T2DM) have large fluctuations in blood glucose (BG), abnormal metabolic function and low immunity to varying degrees, which increases the risk of malignant tumor diseases and affects the efficacy of tumor chemotherapy. Controlling hyperglycemia may have important therapeutic implications for cancer patients. AIM: To clarify the influence of BG fluctuations on chemotherapy efficacy and safety in T2DM patients complicated with lung carcinoma (LC). METHODS: The clinical data of 60 T2DM + LC patients who presented to the First Affiliated Hospital of Ningbo University between January 2019 and January 2021 were retrospectively analyzed. All patients underwent chemotherapy and were grouped as a control group (CG; normal BG fluctuation with a mean fluctuation < 3.9 mmol/L) and an observation group (OG; high BG fluctuation with a mean fluctuation ≥ 3.9 mmol/L) based on their BG fluctuations, with 30 cases each. BG-related indices, tumor markers, serum inflammatory cytokines and adverse reactions were comparatively analyzed. Pearson correlation analysis was performed to analyze the correlation between BG fluctuations and tumor markers. RESULTS: The fasting blood glucose and 2-hour postprandial blood glucose levels in the OG were notably elevated compared with those in the CG, together with markedly higher mean amplitude of glycemic excursions (MAGE), mean of daily differences, largest amplitude of glycemic excursions and standard deviation of blood glucose (P < 0.05). In addition, the OG exhibited evidently higher levels of carbohydrate antigen 19-9, carbohydrate antigen 125, carcinoembryonic antigen, neuron-specific enolase, cytokeratin 19, tumor necrosis factor-α, interleukin-6, and high-sensitivity C-reactive protein than the CG (P < 0.05). Pearson analysis revealed a positive association of MAGE with serum tumor markers. The incidence of adverse reactions was significantly higher in the OG than in the CG (P < 0.05). CONCLUSION: The greater the BG fluctuation in LC patients after chemotherapy, the more unfavorable the therapeutic effect of chemotherapy; the higher the level of tumor markers and inflammatory cytokines, the more adverse reactions the patient experiences.

The dual roles of dissimilatory iron reduction in the carbon cycle: The "iron mesh" effect can increase inorganic carbon sequestration.

Dissimilatory iron reduction (DIR) can drive the release of organic carbon (OC) as carbon dioxide (CO2 ) by mediating electron transfer between organic compounds and microbes. However, DIR is also crucial for carbon sequestration, which can affect inorganic-carbon redistribution via iron abiotic-phase transformation. The formation conditions of modern carbonate-bearing iron minerals (ICFe ) and their potential as a CO2 sink are still unclear. A natural environment with modern ICFe , such as karst lake sediment, could be a good analog to explore the regulation of microbial iron reduction and sequential mineral formation. We find that high porosity is conducive to electron transport and dissimilatory iron-reducing bacteria activity, which can increase the iron reduction rate. The iron-rich environment with high calcium and OC can form a large sediment pore structure to support rapid DIR, which is conducive to the formation and growth of ICFe . Our results further demonstrate that the minimum DIR threshold suitable for ICFe formation is 6.65 µmol g-1 dw day-1 . DIR is the dominant pathway (average 66.93%) of organic anaerobic mineralization, and the abiotic-phase transformation of Fe2+ reduces CO2 emissions by ~41.79%. Our findings indicate that as part of the carbon cycle, DIR not only drives mineralization reactions but also traps carbon, increasing the stability of carbon sinks. Considering the wide geographic distribution of DIR and ICFe , our findings suggest that the "iron mesh" effect may become an increasingly important vector of carbon sequestration.

Prognostic impact of tumor spread through air spaces for T2aN0 stage IB non-small cell lung cancer.

BACKGROUND: Spread through air spaces (STAS) is a pattern of invasion recently identified in non-small cell lung cancer (NSCLC), with a poor prognosis. However, the predictive impact of STAS in stage IB NSCLC is not well understood. This investigation aims to assess the prognostic influence of STAS in stage IB NSCLC. METHODS: We reviewed 130 resected stage IB NSCLC between 2010 and 2015. Beyond the central tumor edge, lung parenchymal air gaps containing cancer cells were identified as STAS. In order to estimate recurrence-free survival (RFS) and overall survival (OS), Cox models and Kaplan-Meier techniques were utilized. Logistic regression analysis was employed to define the factors influencing STAS. RESULTS: Of 130 patients, 72 (55.4%) had STAS. STAS was a significant prognosticator. Kaplan-Meier method showed that STAS-positive patients had a significantly lower OS and RFS than STAS-negative patients (5-year OS, 66.5% vs. 90.4%, p = 0.02; 5-year RFS, 59.5% vs. 89.7%, p = 0.004) In a semiquantitative assessment, the RFS and OS were shorter in survival analysis when STAS increased (5-year RFS, 89.7%, no STAS, 61.8%, low STAS, 57.2%, high STAS, p = 0.013; 5-year OS, 90.4%, no STAS, 78.3%, low STAS, 57.2%, high STAS, p = 0.002). The association between STAS and poor differentiation, adenocarcinoma, and vascular invasion (p value was <0.001, 0.047, and 0.041, respectively) was statistically significant. CONCLUSIONS: The STAS is an aggressive pathological feature. RFS and OS could be significantly reduced by STAS, while it also serves as an independent predictor.

Iron oxides act as an alternative electron acceptor for aerobic methanotrophs in anoxic lake sediments.

Conventional aerobic CH4-oxidizing bacteria (MOB) are frequently detected in anoxic environments, but their survival strategy and ecological contribution are still enigmatic. Here we explore the role of MOB in enrichment cultures under O2 gradients and an iron-rich lake sediment in situ by combining microbiological and geochemical techniques. We found that enriched MOB consortium used ferric oxides as alternative electron acceptors for oxidizing CH4 with the help of riboflavin when O2 was unavailable. Within the MOB consortium, MOB transformed CH4 to low molecular weight organic matter such as acetate for consortium bacteria as a carbon source, while the latter secrete riboflavin to facilitate extracellular electron transfer (EET). Iron reduction coupled to CH4 oxidation mediated by the MOB consortium was also demonstrated in situ, reducing 40.3% of the CH4 emission in the studied lake sediment. Our study indicates how MOBs survive under anoxia and expands the knowledge of this previously overlooked CH4 sink in iron-rich sediments.

Reduced calorie diet combined with NNMT inhibition establishes a distinct microbiome in DIO mice.

Treatment with a nicotinamide N-methyltransferase inhibitor (NNMTi; 5-amino-1-methylquinolinium) combined with low-fat diet (LD) promoted dramatic whole-body adiposity and weight loss in diet-induced obese (DIO) mice, rapidly normalizing these measures to age-matched lean animals, while LD switch alone was unable to restore these measures to age-matched controls in the same time frame. Since mouse microbiome profiles often highly correlate with body weight and fat composition, this study was designed to test whether the cecal microbiomes of DIO mice treated with NNMTi and LD were comparable to the microbiomes of age-matched lean counterparts and distinct from microbiomes of DIO mice maintained on a high-fat Western diet (WD) or subjected to LD switch alone. There were minimal microbiome differences between lean and obese controls, suggesting that diet composition and adiposity had limited effects. However, DIO mice switched from an obesity-promoting WD to an LD (regardless of treatment status) displayed several genera and phyla differences compared to obese and lean controls. While alpha diversity measures did not significantly differ between groups, beta diversity principal coordinates analyses suggested that mice from the same treatment group were the most similar. K-means clustering analysis of amplicon sequence variants by animal demonstrated that NNMTi-treated DIO mice switched to LD had a distinct microbiome pattern that was highlighted by decreased Erysipelatoclostridium and increased Lactobacillus relative abundances compared to vehicle counterparts; these genera are tied to body weight and metabolic regulation. Additionally, Parasutterella relative abundance, which was increased in both the vehicle- and NNMTi-treated LD-switched groups relative to the controls, significantly correlated with several adipose tissue metabolites' abundances. Collectively, these results provide a novel foundation for future investigations.

Therapeutic implications of functional tea ingredients for ameliorating inflammatory bowel disease: a focused review.

Inflammatory bowel disease (IBD) is a chronic gastro-intestinal disorders of unknown etiology. There are several drugs approved for treating IBD patients with active disease, including first-line use of aminosalicylates, and secondary choices of immunomodulators and other therapies. These medications might manage disease symptoms, but have also shown significant side-effects in IBD patients. Tea is the second largest beverage in the world and its main active ingredients including tea polyphenols, polysaccharides and tea pigments have been shown promising anti-inflammatory and antioxidant properties. In this review, we summarize the influence of different tea varieties including green tea, black tea and dark tea as potential nutritional therapy for preventing and treating IBD, and discuss the mechanisms of tea ingredients involved in the regulation of oxidative stress, inflammation, signaling pathways, and gut microbiota that could benefit for IBD disease management. Our observation directs further basic and clinical investigations on tea polyphenols and their derivatives as novel IBD therapeutic agents.

Abundant sediment organic matter potentially facilitates chemical iron reduction and surface water blackness in a Chinese deep lake.

Black bloom has become an increasingly severe environmental and ecological problem in lots of lakes. Ferrous monosulfide (FeS), which is closely related to chemical iron reduction (CIR), is considered the major cause for black water in shallow lakes, but few studies focus on the effect of organic matters (OM) content on iron and sulfate reduction and its contribution to the black bloom in deep lakes. Here, in Lake Fuxian, a Chinese deep lake which has also suffered from black bloom, FeS was identified responsible for the surface water blackness by using multiple microscopy and element analyses. Dissolved oxygen (DO) penetrated 1.6-4.2 mm in all sediment sites, further indicating FeS formed in the sediments instead of the permanently oxic water column. Geochemical characteristics revealed by diffusive gradients in thin films (DGT) showed that DGT-Fe2+ concentration was 57.6-1919.4 times higher than the DGT-S2- concentration and both were positively correlated with DGT-PO43-. Combining DGT profiles and anaerobic OM remineralization rate according to bag incubation, iron reduction is more effective than sulfate reduction although the two processes coexisted. Moreover, correlation of DGT-Fe2+ and DGT-PO43- was better than that of DGT-PO43- and DGT-S2- at OM-depleted sites but opposite at OM-rich sites. In addition, total organic carbon (TOC) was significantly positively related to acid volatile sulfide (AVS). We therefore conclude that abundant OM potentially exacerbate chemical iron reduction and further lead to surface water blackness. Our study revealed the mechanisms behind the black bloom and gives credence to the management strategy of reducing OM loading to protect water quality in deep lakes.

Genomic Analysis for Antioxidant Property of Lactobacillus plantarum FLPL05 from Chinese Longevity People.

Antioxidant activity is one of the important probiotic characteristics for lactic acid bacteria including Lactobacillus plantarum, which is used for food fermentation or as a probiotic supplement. L. plantarum FLPL05 is a novel strain originally isolated from a healthy elderly individual of longevity. The organism has been demonstrated to exhibit high antioxidant property. However, there are limited genomic insights into the antioxidant properties of this organism. In this study, we performed whole-genome analysis regarding its antioxidant property. L. plantarum FLPL05 exhibited higher antioxidant activity compared with that of L. plantarum strains ATCC14917, ATCC8014, and WCFS1. The antioxidant capacity of L. plantarum FLPL05 was genetically linked to its antioxidant system, i.e., glutathione and thioredoxin involved in global regulation of defense against hydrogen peroxide challenge. L. plantarum FLPL05 was further examined for its antioxidant potential in D-Gal-induced aging mice and exhibited a significant increase in the activity of serum glutathione peroxidase (GSH-PX) and a decrease in the level of malondialdehyde (MDA). Moreover, our analyses exhibited a complete gene cluster including plnA, plnB, plnC, plnD, plnE, plnF, plnG, plnH, plnI, plnJ, plnK, plnM, plnN, plnO, plnP, plnQ, plnST, plnU, plnV, plnW, plnX, and plnY for production of bacteriocin. Our results suggest that L. plantarum FLPL05 could be a probiotic candidate.

Halomonas rituensis sp. nov. and Halomonas zhuhanensis sp. nov., isolated from natural salt marsh sediment on the Tibetan Plateau.

Two novel Gram-stain-negative, aerobic and non-motile rods bacteria, designated TQ8ST and ZH2ST, were isolated from salt marsh sediment collected from the Tibetan Plateau. Strain TQ8ST was found to grow at 10-40 °C (optimum, 30 °C), pH 6.0-11.0 (optimum, pH 8.0-9.0) and in the presence of 2-12 % (w/v) NaCl (optimum, 6-8 %). Strain ZH2ST was found to grow at 15-40 °C (optimum, 30 °C), pH 7.0-10.0 (optimum pH 9.0) and in the presence of 2-10 % (w/v) NaCl (optimum, 4-6 %). Phylogenetic analysis based on the 16S rRNA gene sequences showed that strains TQ8ST and ZH2ST shared 99.07 % sequence similarity between each other and were affiliated with the genus Halomonas, sharing 97.48 % and 97.41 % of sequence similarity to their closest neighbour Halomonas sulfidaeris Esulfide1T, respectively. DNA-DNA hybridization analyses showed 61.0 % relatedness between strains TQ8ST and ZH2ST. The average nucleotide identity and the average amino acid identity values between the two genomes were 92.33 and 92.84 %, respectively. The values between the two strains and their close phylogenetic relatives were all below 95 %. The major respiratory quinones of strain TQ8ST were Q-9 and Q-8, while that of ZH2ST was Q-9. The main fatty acids shared by the two strains were C18 : 1 ω6c and/or C18 : 1 ω7c, C16 : 1 ω6c and/or C16 : 1 ω7c, C16 : 0 and C12 : 0 3-OH. Strain ZH2ST can be distinguished from TQ8ST by a higher proportion of C19 : 0 cyclo ω8c. The G+C content of the genomic DNA of strains TQ8ST and ZH2ST were 57.20 and 57.14 mol%, respectively. On the basis of phenotypic distinctiveness and phylogenetic divergence, the two isolates are considered to represent two novel species of the genus Halomonas, for which the names Halomonas rituensis sp. nov (type strain TQ8ST=KCTC 62530T=CICC 24572T) and Halomonas zhuhanensis sp. nov (type strain ZH2ST=KCTC 62531T=CICC 24505T) are proposed.

Impact of herbs and dietary supplements in patients with fibromyalgia: A protocol for a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Fibromyalgia (FM) is a common chronic pain condition that seriously affects the quality of patient lives. Its etiology, pathogenesis, and treatment still remain uncertain. Dietary supplements have been widely trialed for symptom relief for FM. The review aims to synthesize the previous literature publications to assess the impact of herbs and dietary supplements on FM patients. METHODS: We will conduct a literature search in the following databases PubMed, MEDLINE, EMBASE, Cochrane Library, Scopus, and Global Health from database inception to December 2019. Clinical studies published in the English language that used human participants and address the efficacy, safety, and acceptability of herbs and dietary supplements on individuals with FM will be included. The risk of bias and quality assessment of each trial will be evaluated. If trials are enough, a meta-analysis will be conducted using software RevMan5.3, Cochrane Collaboration. RESULT: Our review will be the first attempt to facilitate evidence-based management using herbs and dietary supplements to treat patients with FM. CONCLUSION: The findings may provide a framework for future research and clinic practice in FM management. PROSPERO REGISTRATION NUMBER: CRD42020149941.

Probiotic Enterococcus faecalis Symbioflor 1 ameliorates pathobiont-induced miscarriage through bacterial antagonism and Th1-Th2 modulation in pregnant mice.

The bacterium-bacterium interaction between pathogenic and probiotic Enterococcus as well as the bacterium-host interaction between Enterococcus and intestinal epithelium has drawn increasing attentions, but the influence of those interactions on host pregnancy remains largely unexplored. In the present study, we evaluated the effects of probiotic E. faecalis Symbioflor 1 or/and pathogenic E. faecalis OG1RF on the miscarriage of pregnant mice. Using in vitro assays of competition and exclusion and displacement, antagonistic property of E. faecalis Symbioflor 1 against E. faecalis OG1RF was observed, and the former inhibited the translocation of the later in vivo. The rate of miscarriage induced by E. faecalis OG1RF challenge was significantly reduced by 28% with E. faecalis Symbioflor 1 intervention; and the tissue integrity of ileum, colon, uterus, and placenta and placental blood cell density in pregnant mice were drastically improved by such probiotic intervention. Compared with the controls, probiotic intervention significantly upregulated the level of IL-10 and TGF-ß, downregulated levels of IFN-γ, and increased progesterone level that reversed the trend of being Th1 predominance state reported for adverse pregnancy outcome at early pregnancy stage. In conclusion, E. faecalis Symbioflor 1 decreased the translocation of E. faecalis OG1RF, prevented pathogen-induced tissue damage, and changed Th1-Th2 homeostasis toward Th2 predominance during early pregnancy resulting in decreased miscarriage. KEY POINTS: •The mechanism of how probiotic E. faecalis Symbioflor 1 improves pregnancy of mice • Influence of interactions of pathogenic and probiotic Enterococcus on host pregnancy • E. faecalis Symbioflor 1 change Th1-Th2 homeostasis toward Th2 predominance.

Electroacupuncture improves cognitive deficits and insulin resistance in an OLETF rat model of Al/D-gal induced aging model via the PI3K/Akt signaling pathway.

To investigate the effect of electroacupuncture (EA) on cognitive function and insulin resistance (IR) in an Al/D-gal-induced aging model for Alzheimer's disease (AD) using Ostuka Long-Evans Tokushima Fatty (OLETF) rats. The Al/D-gal-OLETF rats for AD were randomly divided into the EA and non-EA groups. Cognitive function was assessed using the Morris water maze (MWM). The morphology of the hippocampal neurons was observed using hematoxylin & eosin (H&E) staining. Aß and total Tau in the hippocampus and cerebrospinal fluid (CSF) were detected using western blotting (WB) and enzyme-linked immunosorbent assay (ELISA). Fasting blood glucose (FPG) was determined using the glucose oxidase method. Plasma fasting insulin (FINS), serum C-peptide (C-P), and CSF insulin were detected using ELISA. The expression of the genes and proteins in the PI3K signaling pathway was detected using quantitative real-time PCR and WB. After EA intervention, the hippocampal Aß and total Tau protein levels, body weight, FPG, FINS, and C-P were significantly decreased. The MWM showed that the percentage of time in the target quadrant of the EA group was elevated in the probe test. The protein levels of p-IRS1, p-IRS2, IDE, and p-GSK3ß were significantly increased, while p-PI3K-p85α and p-Akt were decreased. In conclusion, EA improves cognitive function and insulin resistance in rat models of AD. The PI3K/Akt signaling pathway is involved in those changes.

Halomonas montanilacus sp. nov., isolated from hypersaline Lake Pengyanco on the Tibetan Plateau.

A Gram-stain-negative, catalase- and oxidase-positive, aerobic, rod-shaped, motile strain (PYC7WT) was isolated from Lake Pengyanco on the Tibetan Plateau. Comparisons based on 16S rRNA gene sequences showed that strain PYC7WT belongs to the genus Halomonas, with Halomonas malpeensis YU-PRIM-29T and Halomonas johnsoniae T68687T as its closest neighbours (96.8 and 96.6 % 16S rRNA gene sequence similarity, respectively), and only 93.1 % 16S rRNA gene sequence similarity to Halomonas elongata ATCC 33173T. The predominant respiratory quinone of strain PYC7WT is Q-9, with Q-8 as a minor component. The major fatty acids are C18 : 1 ω6c and / or C18 : 1 ω7c, C16 : 0, C16 : 1 ω6c and/or C16 : 1 ω7c, and C12 : 0 3OH. The polar lipids of strain PYC7WT include phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and two unidentified phospholipids. Genome sequencing revealed a genome size of 4.79 Mbp and a G+C content of 62.9 mol%. DNA-DNA hybridization values of strain PYC7WT showed 45, 30 and 38 % relatedness with Halomonas johnsoniae DSM 21197T, Halomonas hamiltonii DSM 21196T and Halomonas stevensii DSM 21198T, respectively. Combining phenotypic, biochemical, genotypic and DNA-DNA hybridization data, we propose that strain PYC7WT represents a novel species within the genus Halomonas and to have the name Halomonas montanilacus sp. nov.; PYC7WT (=CICC 24506T= KCTC 62529T) is the type strain.

Proteomic analysis reveals potential factors associated with enhanced EPS production in Streptococcus thermophilus ASCC 1275.

Streptococcus thermophilus ASCC 1275 has two chain length determining genes - epsC and epsD- in its eps gene cluster, and produces two times more EPS in sucrose medium than that in glucose and lactose. Hence, we investigated the influence of sugars (glucose, sucrose and lactose), at log phase (5 h) and stationary phase (10 h), on the global proteomics of S. thermophilus 1275 to understand the differentially expressed proteins (DEPs) during EPS production using isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analysis. Among 98 DEPs in sucrose medium, most of them were mapped into EPS biosynthesis pathway and other related metabolisms. There was an upregulation of several proteins involved in sugar transport (phosphoenolpyruvate (PEP) phosphotransferase system), EPS assembly (epsG1D) and amino acid metabolism (methionine, cysteine/arginine metabolism) in sucrose medium. This study showed that increased EPS production in S. thermophilus 1275 requires a well-co-ordinated regulation of pathway involved in both EPS assembly and amino acid metabolism along with the availability of sugars. Thus, it provided valuable insights into the biosynthesis and regulation of EPS in S. thermophilus 1275, and potential gene targets for understanding high-EPS strains.

Functional Genomic Analyses of Exopolysaccharide-Producing Streptococcus thermophilus ASCC 1275 in Response to Milk Fermentation Conditions.

Exopolysaccharide (EPS) produced from dairy bacteria improves texture and functionalities of fermented dairy foods. Our previous study showed improved EPS production from Streptococcus thermophilus ASCC1275 (ST1275) by simple alteration of fermentation conditions such as pH decrease (pH 6.5 → pH 5.5), temperature increase (37°C → 40°C) and/or whey protein isolate (WPI) supplementation. The iTRAQ-based proteomics in combination with transcriptomics were applied to understand cellular protein expression in ST1275 in response to above shifts during milk fermentation. The pH decrease induced the most differentially expressed proteins (DEPs) that are involved in cellular metabolic responses including glutamate catabolism, arginine biosynthesis, cysteine catabolism, purine metabolism, lactose uptake, and fatty acid biosynthesis. Temperature increase and WPI supplementation did not induce much changes in global protein express profiles of ST1275 between comparisons of pH 5.5 conditions. Comparative proteomic analyses from pairwise comparisons demonstrated enhanced glutamate catabolism and purine metabolism under pH 5.5 conditions (Cd2, Cd3, and Cd4) compared to that of pH 6.5 condition (Cd1). Concordance analysis for differential expressed genes (DEGs) and DEPs highlighted down-regulated glutamate catabolism and up-regulated arginine biosynthesis in pH 5.5 conditions. Down regulation of glutamate catabolism was also confirmed by pathway enrichment analysis. Down-regulation of EpsB involved in EPS assembly was observed at both mRNA and protein level in pH 5.5 conditions compared to that in pH 6.5 condition. Medium pH decreased to mild acidic level induced cellular changes associated with glutamate catabolism, arginine biosynthesis and regulation of EPS assembly in ST1275.

Roseovarius tibetensis sp. nov., a halophilic bacterium isolated from Lake LongmuCo on Tibetan Plateau.

Two Gram-stain negative halophilic strains, designated as LM2T and LM4, were isolated from Lake LongmuCo on Tibetan Plateau. These two strains were aerobic, catalaseand oxidase-positive, nonmotile and rod-shaped organisms. Phylogenetic analysis based on 16S rRNA gene sequences indicated that LM2T and LM4 belong to the genus Roseovarius, with Roseovarius tolerans EL-172T (97.3% and 97.4% 16S rRNA gene sequence similarity, respectively) and Roseovarius azorensis SSW084T (95.5% and 95.6% 16S rRNA gene sequence similarity, respectively) as their closest neighbors. Q-10 was the sole respiratory quinone of these two strains. The major fatty acids were C18:1ω7c/C18:1ω6c, C16:0, C19:0 cyclo ω8c, and 11-methyl C18:1ω7c. The polar lipids included phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phospholipid of unknown structure containing glucosamine, and unidentified aminolipid. The DNA G + C content was between 64.2 and 64.5 mol%. DNA-DNA hybridization showed 96.7% relatedness between LM2T and LM4, 24.9% relatedness between LM2T and R. tolerans EL-172T, and 36.3% relatedness between LM4 and R. tolerans EL-172T. Based on phylogenetic analysis, DNA-DNA hybridization, a range of physiological and biochemical characteristics, LM2T and LM4 belong to the same species and were clearly distinguished from the type strains of the genus Roseovarius. It was evident that LM2T and LM4 could be classified as a novel species of the genus Roseovarius, for which the name Roseovarius tibetensis sp. nov. is proposed. The type strain is LM2T (= CGMCC 1.16230T = KCTC 62028T).

Halomonas tibetensis sp. nov., isolated from saline lakes on Tibetan Plateau.

Strains pyc13T and ZGT13 were isolated from Lake Pengyan and Lake Zigetang on Tibetan Plateau, respectively. Both strains were Gram-negative, catalase- and oxidase-positive, aerobic, rod-shaped, nonmotile, and nonflagellated bacteria. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains pyc13T and ZGT13 belong to the genus Halomonas, with Halomonas alkalicola 56-L4-10aEnT as their closest neighbor, showing 97.4% 16S rRNA gene sequence similarity. The predominant respiratory quinone of both strains was Q-9, with Q-8 as a minor component. The major fatty acids of both strains were C18:1ω6c/C18:1ω7c, C16:1ω6c/C16:1ω7c, C16:0, and C12:0 3OH. The polar lipids of both strains consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, glycolipid, phospholipids of unknown structure containing glucosamine, and unidentified phospholipids. The DNA G + C content of pyc13T and ZGT13 were 62.6 and 63.4 mol%, respectively. The DNA-DNA hybridization values of strain pyc13T were 34, 41, 61, 35, and 35% with the reference strains H. alkalicola 56-L4-10aEnT, H. sediminicola CPS11T, H. mongoliensis Z-7009T, H. ventosae Al12T, and H. fontilapidosi 5CRT, respectively. Phenotypic, biochemical, genotypic, and DNA-DNA hybridization data showed that strains pyc13T and ZGT13 represent a new species within the genus Halomonas, for which the name H. tibetensis sp. nov. is proposed. The type strain is pyc13T (= CGMCC 1.15949T = KCTC 52660T).

Pelagibacterium montanilacus sp. nov., an alkaliphilic bacterium isolated from Lake Cuochuolong on the Tibetan Plateau.

A Gram-stain negative, alkaliphilic and halotolerant bacterium, designated CCL18T, was isolated from Lake Cuochuolong on the Tibetan Plateau. The strain was aerobic, short rod-shaped, catalase- and oxidase-positive, and motile by means of several polar flagella. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain CCL18T belongs to the genus Pelagibacterium, with its two closest neighbours being Pelagibacterium halotolerans B2T (96.6 %, 16S rRNA gene sequence similarity) and Pelagibacterium luteolum 1_C16_27T (96.1 %). The predominant respiratory quinone of strain CCL18T was Q-10, with Q-9 as a minor component. The major fatty acids were C18 : 1ω6c/C18 : 1ω7c (60.4 %), C19 : 0cyclo ω8c (8.1 %) and C18 : 0 (6.8 %). The polar lipids included phosphatidylglycerol, diphosphatidylglycerol, seven kinds of unidentified lipids and three kinds of glycolipids. The DNA G+C content was 60.1 mol%. DNA-DNA hybridization showed 35.2 % relatedness between strain CCL18T and P. halotolerans B2T and 24.6 % relatedness to P. luteolum 1_C16_27T. Based on phylogenetic analysis, DNA-DNA hybridization and a range of physiological and biochemical characteristics, strain CCL18T was clearly distinguishable from the other strains of the genus Pelagibacterium. It was evident that strain CCL18T could be classified as a novel species of the genus Pelagibacterium, for which the name Pelagibacterium montanilacus sp. nov. is proposed. The type strain is CCL18T (=CGMCC 1.16231T=KCTC 62030T).

Comparative mRNA-Seq Analysis Reveals the Improved EPS Production Machinery in Streptococcus thermophilus ASCC 1275 During Optimized Milk Fermentation.

Exo-polysaccharide (EPS) produced by dairy starters plays critical roles in improving texture and functionalities of fermented dairy products. One of such high EPS producers, Streptococcus thermophilus ASCC 1275 (ST1275) was used as a model dairy strain to understand the stimulation of its EPS production under optimal milk fermentation conditions. The mRNA-seq analysis and targeted pathway analysis indicate that genes associated with lactose (milk sugar) catabolism, EPS assembly, proteolytic activity, and arginine/methionine/cysteine synthesis and transport in ST1275 were significantly up-regulated under the optimized conditions of pH 5.5, 40°C, or WPI supplementation compared to that of pH 6.5 and 37°C, respectively. This indicates that genes involved in above metabolisms cooperate together for improving EPS yield from ST1275. This study provides a global view map on potential targeted pathways and specific genes accounted for enhanced EPS production in Str. thermophilus and that could be modulated by fermentation conditions.

Evolution and adaptation of SAR11 and Cyanobium in a saline Tibetan lake.

Lake Qinghai is a unique lacustrine ecosystem located on the Tibetan Plateau and exhibits oligotrophic, alkaline, and saline conditions. Previous studies have focused on the community phylogenetic diversity of bacterioplankton in the ecosystem. This study aimed to address the ecotype diversity of bacterioplankton populations in the unique microbial habitat, using metagenomic sequencing and analysis. Phylogenetic analysis revealed two major bacterial populations: SAR11 IIIa (14% of the total) and Cyanobium (14%). Although the two populations shared high 16S rRNA gene sequence identity (> 98% identity) with their closest marine counterparts, they displayed substantial genomic divergence (≤ 80% average amino acid sequence identity). Comparative genomic analysis identified conservation of carbon and energy storage metabolism (biosynthesis of polyphosphate and polyhydroxyalkanoate) gene operons in the SAR11 IIIa and a cyanate (potential nitrogen source in alkaline conditions) transporter gene operon in the Cyanobium. We further identified genetic signature of positive selection acting on an exodeoxyribonuclease gene of the SAR11 IIIa population, which is potentially associated with DNA repair responsive to strong UV radiation on the high altitude mountain. Taken together, our results revealed the ecosystem-specific gene content of the bacterioplankton populations and provided new insights into their adaptations unique to the Tibetan lake.