Early Stage Adaptation of a Mesophilic Green Alga to Antarctica: Systematic Increases in Abundance of Enzymes and LEA Proteins.

It is known that adaptive evolution in permanently cold environments drives cold adaptation in enzymes. However, how the relatively high enzyme activities were achieved in cold environments prior to cold adaptation of enzymes is unclear. Here we report that an Antarctic strain of Chlorella vulgaris, called NJ-7, acquired the capability to grow at near 0 °C temperatures and greatly enhanced freezing tolerance after systematic increases in abundance of enzymes/proteins and positive selection of certain genes. Having diverged from the temperate strain UTEX259 of the same species 2.5 (1.1-4.1) to 2.6 (1.0-4.5) Ma, NJ-7 retained the basic mesophilic characteristics and genome structures. Nitrate reductases in the two strains are highly similar in amino acid sequence and optimal temperature, but the NJ-7 one showed significantly higher abundance and activity. Quantitative proteomic analyses indicated that several cryoprotective proteins (LEA), many enzymes involved in carbon metabolism and a large number of other enzymes/proteins, were more abundant in NJ-7 than in UTEX259. Like nitrate reductase, most of these enzymes were not upregulated in response to cold stress. Thus, compensation of low specific activities by increased enzyme abundance appears to be an important strategy for early stage cold adaptation to Antarctica, but such enzymes are mostly not involved in cold acclimation upon transfer from favorable temperatures to near 0 °C temperatures.

Chemical Sectioning for Immunofluorescence Imaging.

Immunofluorescence (IF) is a powerful investigative tool in biological research and medical diagnosis, whereas conventional imaging methods are always conflict between speed, contrast/resolution, and specimen volume. Chemical sectioning (CS) is an effective method to overcome the conflict, which works by chemically manipulating the off/on state of fluorescent materials and turning on only the extremely superficial surface fluorescence of tissues to realize the sectioning capacity of wide-field imaging. However, the current mechanism of CS is only applicable to samples labeled with pH-sensitive fluorescent proteins and still cannot fulfill samples immunolabeled with frequently used commercial fluorescent dyes. Here, immunofluorescence chemical sectioning (IF-CS) is described to present an off/on mechanism for Alexa dyes by complexation reactions, allowing CS imaging of IF labeled tissues. IF-CS enables IF freeing from out-of-focus interference in wide-field imaging and satisfying with multicolor imaging. IF-CS demonstrates the utility of the 3D submicron-resolution imaging of large immunolabeled tissues on the wide-field block-face system. IF-CS may remarkably facilitate systematic studies of refined subcellular architectures of endogenous proteins in intact biological systems.

Regulatory function of sigma factors RpoS/RpoN in adaptation and spoilage potential of Shewanella baltica.

Shewanella baltica is a typical specific spoilage organism causing the deterioration of seafood, but the exact regulation of its adaptive and competitive dominance in diverse environments remains undefined. In this study, the regulatory function of two sigma factors, RpoS and RpoN, in environmental adaptation and spoilage potential were evaluated in S. baltica SB02. Two in-frame deletion mutants, ΔrpoS and ΔrpoN, were constructed to explore the roles in their motility, biofilm formation, stress response and spoilage potential, as well as antibiotics by comparing the phenotypes and transcription with those of wild type (WT) strain. Compared with WT strain, the ΔrpoN showed the slower growth and weaker motility due to loss of flagella, while swimming of the ΔrpoS was increased. Deletion of rpoN significantly decreased biofilm biomass, and production of exopolysaccharide and pellicle, resulting in a thinner biofilm structure, while ΔrpoS formed the looser aggregation in biofilm. Resistance of S. baltica to NaCl, heat, ethanol and three oxidizing disinfectants apparently declined in the two mutants compared to WT strain. The ΔrpoN mutant decreased sensory score, accumulation of trimethylamine, putrescine and TVB-N and protease activity, while a weaker effect was observed in ΔrpoS. The two mutants had significantly higher susceptibility to antibiotics than WT strain, especially ΔrpoN. Deficiency of rpoN and rpoS significantly repressed the activities of two diketopiperazines related to quorum sensing (QS). Furthermore, transcriptome analyses revealed that RpoN was involved in the regulation of the expression of 143 genes, mostly including flagellar assembly, nitrogen and amino acid metabolism, ABC transporters. Transcript changes of seven differentially expressed coding sequences were in agreement with the phenotypes observed in the two mutants. Our findings reveal that RpoN, as a central regulator, controls the fitness and bacterial spoilage in S. baltica, while RpoS is a key regulatory factor of stress response. Characterization of these two sigma regulons in Shewanella has expanded current understanding of a possible co-regulatory mechanism with QS for adaptation and spoilage potential.

Diminished 25-OH vitamin D3 levels and vitamin D receptor variants are associated with susceptibility to type 2 diabetes with coronary artery diseases.

BACKGROUND: Role of plasma vitamin D and genetic variants of its receptor (VDR) in susceptibility to different diseases has been documented. Various studies in different populations have been highlighted strong associations with diabetes and cardiovascular diseases. Vitamin D deficiency has been linked with the development of type 2 diabetes (T2D) and the onset of coronary artery diseases (CAD). However, the role of vitamin D in predisposition to CAD in patients with T2D is ill-defined. MATERIALS AND METHODS: We enrolled 674 Chinese T2D patients, and based on clinical phenotype, patients were further categorized into patients with (n = 138) or without coronary artery disease (n = 536). Five hundred twenty-one healthy subjects from similar geographical areas, free from diabetic or coronary disorders, were enrolled as controls. Serum levels of 25-OH vitamin D were quantified by ELISA. Common VDR (FokI, TaqI, BsmI, and ApaI) polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Patients with T2D displayed lower levels of 25-OH vitamin D compared with healthy controls. Furthermore, T2D patients with CAD clinical phenotype had the lowest levels of vitamin D. Prevalence of FokI and TaqI mutants was significantly higher in diabetic patients when compared to controls. Interestingly, Tt genotype was more frequent in the artery disease group in comparison with T2D patients without heart involvement. Combined analysis of VDR polymorphisms and serum levels of vitamin D revealed a significant role in predisposition to T2D with or without CAD. CONCLUSIONS: Lower vitamin D levels and variants of VDR polymorphisms (FokI and TaqI) are associated with susceptibility to T2D and clinical manifestation.

Sublethal ß-lactam antibiotics induce PhpP phosphatase expression and StkP kinase phosphorylation in PBP-independent ß-lactam antibiotic resistance of Streptococcus pneumoniae.

StkP and PhpP of Streptococcus pneumoniae have been confirmed to compose a signaling couple, in which the former is a serine/threonine (Ser/Thr) kinase while the latter was annotated as a phosphotase. StkP has been reported to be involved in penicillin-binding protein (PBP)-independent penicillin resistance of S. pneumoniae. However, the enzymatic characterization of PhpP and the role of PhpP in StkP-PhpP couple remain poorly understood. Here we showed that 1/4 minimal inhibitory concentration (MIC) of penicillin (PCN) or cefotaxime (CTX), the representatives of ß-lactam antibiotics, could induce the expression of stkP and phpP genes and phosphorylation of StkP in PCN/CTX-sensitive strain ATCC6306 and three isolates of S. pneumoniae (MICs: 0.02-0.5 µg/ml). The product of phpP gene hydrolyzed PP2C type Ser/Thr phosphotase-specific RRA (pT)VA phosphopeptide substrate with the Km and Kcat values of 277.35 µmoL/L and 0.71 S-1, and the hydrolytic activity was blocked by sodium fluoride, a PP2C type Ser/Thr phosphatase inhibitor. The phosphorylation levels of StkP in the four phpP gene-knockout (ΔphpP) mutants were significantly higher than that in the wild-type strains. In particular, the MICs of PCN and CTX against the ΔphpP mutants were significantly elevated as 4-16 µg/ml. Therefore, our findings confirmed that sublethal PCN and CTX act as environmental inducers to cause the increase of phpP and stkP gene expression and StkP phosphorylation. PhpP is a PP2C type Ser/Thr protein phosphatase responsible for dephosphorylation of StkP. Knockout of the phpP gene results in a high level of StkP phosphorylation and PBP-independent PCN/CTX resistance of S. pneumoniae.

Epidemiological analysis and rapid detection by one-step multiplex PCR assay of Haemophilus influenzae in children with respiratory tract infections in Zhejiang Province, China.

BACKGROUND: Haemophilus influenzae (H. influenzae) is one of the most important pathogenic bacteria causing respiratory tract infection diseases in children. There are two main types of H. influenzae, encapsulated H. influenzae and nontypeable H. influenzae (NTHi). Serotype b of H. influenzae (Hib) used to be the main epidemic type of H. influenzae, causing the invasive infection. However, the epidemiology of invasive H. influenzae disease has changed substantially, and most invasive diseases are now caused by NTHi and other serotypes of H. influenzae. The aim of this study was to determine the main epidemic strains of H. influenzae in Zhejiang Province in China, and establish a one-step multiplex PCR assay to distinguish H. influenzae from other bacteria associated with respiratory tract infections, and distinguish encapsulated H. influenzae from NTHi. METHOD: In this study, bacterial culture and serum agglutination testing were used to determine the most prevalent serotype of H. influenzae, and the results have served as a gold standard for clinical diagnosis. We also designed a one-step multiplex PCR assay using several kinds of standard strains of respiratory tract infection bacteria, to examine the stability, specificity, and detection limit of the PCR assays. We then used 1514 nasopharyngeal secretion (NPS) samples collected from children with respiratory tract infections to verify the specificity and sensitivity of the PCR assay. RESULTS: The bacterial culture and serum agglutination test results showed that the positive rates of H. influenzae and encapsulated H. influenzae were 18.49 and 1.18%, respectively. The PCR results showed that the detection limit of the multiplex PCR assay was 1.89 × 103 copies /µL, the ompP6 positive rate was 19.35%, and the bexA positive rate was 1.32%. The sensitivity and specificity of the multiplex PCR were 100 and 99.86%, respectively. CONCLUSIONS: According to our study, the most prevalent H. influenzae subtype in Zhejiang Province was NTHi, account for 93.57%; the one-step multiplex PCR assay we established can be used as the differential detection of clinical H. influenzae strains, replacing routine bacterial culture and serum agglutination testing.

Annexin A2 is involved in the production of classical swine fever virus infectious particles.

Annexin A2 (ANXA2) is an important host factor regulating several key processes in many viruses. To evaluate the potential involvement of ANXA2 in the life cycle of classical swine fever virus (CSFV), an RNA interference (RNAi) approach was utilized. Knockdown of ANXA2 did not impair CSFV RNA replication but significantly reduced CSFV production. A comparable reduction of extracellular and intracellular infectivity levels was detected, indicating that ANXA2 might play a role in CSFV assembly rather than in genome replication and virion release. Furthermore, ANXA2 was found to bind CSFV NS5A, an essential replicase component. Amino acids R338, N359, G378 of NS5A were revealed to be pivotal for the ANXA2-NS5A interaction. Substitutions of these amino acids had no effect on viral RNA replication but substantially reduced CSFV production, which might partly be due to these mutations destroying the ANXA2-NS5A interaction. These results suggested that ANXA2 might participate in CSFV production process by binding NS5A.

Phosphatidic acid integrates calcium signaling and microtubule dynamics into regulating ABA-induced stomatal closure in Arabidopsis.

Specific cellular components have been identified to function in abscisic acid (ABA) regulation of stomatal apertures, including calcium, the cytoskeleton, and phosphatidic acid. In this study, the regulation and dynamic organization of microtubules during ABA-induced stomatal closure by phospholipase D (PLD) and its product PA were investigated. ABA induced microtubule depolymerization and stomatal closure in wide-type (WT) Arabidopsis, whereas these processes were impaired in PLD mutant (pldα1). The microtubule-disrupting drugs oryzalin or propyzamide induced microtubule depolymerization, but did not affect the stomatal aperture, whereas their co-treatment with ABA resulted in stomatal closure in both WT and pldα1. In contrast, the microtubule-stabilizing drug paclitaxel arrested ABA-induced microtubule depolymerization and inhibited ABA-induced stomatal closure in both WT and pldα1. In pldα1, ABA-induced cytoplasmic Ca(2+) ([Ca(2+)]cyt) elevation was partially blocked, and exogenous Ca(2+)-induced microtubule depolymerization and stomatal closure were impaired. These results suggested that PLDα1 and PA regulate microtubular organization and Ca(2+) increases during ABA-induced stomatal closing and that crosstalk among signaling lipid, Ca(2+), and microtubules are essential for ABA signaling.

Human papillomavirus prevalence and type-distribution among women in Zhejiang Province, Southeast China: a cross-sectional study.

BACKGROUND: Human papillomavirus (HPV) infection is the main etiological factor for cervical cancer and premalignant lesions of the cervix. The purposes of the present study were to determine the prevalence of type-specific HPV infections and the association of different HPV types with cervical dysplasia among women in Zhejiang province, Southeast China. METHODS: A total of 15,267 women presenting to a gynaecological outpatient clinic were enrolled in this study. Women were screened for HPV in addition to routine cervical cytology testing. Microarray hybridization and liquid-based cytology tests were used to detect HPV genotypes and cervical cytology, respectively. RESULTS: Based on the population attending a gynaecological outpatient clinic, overall prevalence of any 23 HPV type was 22.8% and multiple HPV infection was found in 4.0% of all the outpatients. HPV prevalence showed bimodal age distribution, with a peak (55.7%) at the ≤20 age group and a second one (35.5%) at >60 age group. In total samples, the five most frequent types were HPV 16 (4.4%), 58 (2.9%), 52 (2.7%), 33 (2.2%) and 11 (1.9%). Overall HPV prevalence increased with the severity of the cytologic result. Analysis through crude odds ratios (ORs) revealed that the cervical lesion risk of HPV-infected women increased to about 26-fold of uninfected women (OR 26.1, 95% CI 22.4 to 30.3). The five most risky HPV types associated with abnormal cytology were HPV 73, 16, 82, 45 and 51. CONCLUSIONS: This study provided baseline data on HPV prevalence in women attending a gynecological outpatient clinic in Zhejiang province. Our data will supply guidance for the primary screening and vaccination program for cervical cancer in this area.

Analysis on effect of psychological nursing combined with extended care for improving negative emotions and self-care ability in patients with colorectal cancer and enterostomy: A retrospective study.

This study investigates the effectiveness of combining psychological nursing with extended nursing in patients with colorectal cancer who have undergone enterostomy. Conducted from January 2021 to January 2022, this retrospective study involved 78 patients split into 2 groups of 39 each. The control group received standard nursing care, while the observation group benefitted from both psychological and extended nursing. The evaluation focused on anxiety, depression, sleep quality, mental resilience, and self-care abilities. Results, 3 months postdischarge, indicated that the observation group had significantly lower scores in the Hamilton Depression Rating Scale and the Pittsburgh Sleep Quality Index, and higher scores in the Connor-Davidson Resilience Scale and the Enterostomal Self-Care Ability Scale, compared to the control group (P < .05). The findings suggest that integrating psychological nursing with extended care significantly improves mood, sleep quality, psychological resilience, and self-care capabilities in these patients.

Peptidoglycan biosynthesis-associated enzymatic kinetic characteristics and ß-lactam antibiotic inhibitory effects of different Streptococcus pneumoniae penicillin-binding proteins.

Penicillin-binding proteins (PBPs) include transpeptidases, carboxypeptidases, and endopeptidases for biosynthesis of peptidoglycans in the cell wall to maintain bacterial morphology and survival in the environment. Streptococcus pneumoniae expresses six PBPs, but their enzymatic kinetic characteristics and inhibitory effects on different ß-lactam antibiotics remain poorly understood. In this study, all the six recombinant PBPs of S. pneumoniae displayed transpeptidase activity with different substrate affinities (Km = 1.56-9.11 mM) in a concentration-dependent manner, and rPBP3 showed a greater catalytic efficiency (Kcat = 2.38 s-1) than the other rPBPs (Kcat = 3.20-7.49 × 10-2 s-1). However, only rPBP3 was identified as a carboxypeptidase (Km = 8.57 mM and Kcat = 2.57 s-1). None of the rPBPs exhibited endopeptidase activity. Penicillin and cefotaxime inhibited the transpeptidase and carboxypeptidase activity of all the rPBPs but imipenem did not inhibited the enzymatic activities of rPBP3. Except for the lack of binding of imipenem to rPBP3, penicillin, cefotaxime, and imipenem bound to all the other rPBPs (KD = 3.71-9.35 × 10-4 M). Sublethal concentrations of penicillin, cefotaxime, and imipenem induced a decrease of pneumococcal pbps-mRNA levels (p < 0.05). These results indicated that all six PBPs of S. pneumoniae are transpeptidases, while only PBP3 is a carboxypeptidase. Imipenem has no inhibitory effect on pneumococcal PBP3. The pneumococcal genes for encoding endopeptidases remain to be determined.

The transcription factor PbbHLH164 is destabilized by PbRAD23C/D.1 and mediates ethylene biosynthesis during pear fruit ripening.

The phytohormone ethylene plays an important role in climacteric fruit ripening. However, the knowledge on molecular regulation of ethylene biosynthesis remains limited in pear fruit. Herein, a new basic helix-loop-helix transcription factor, PbbHLH164, was identified based on the transcriptome analysis of different developing and ripening fruits of two pear cultivars 'Sucui No. 1' and 'Cuiguan'. PbbHLH164 was more highly expressed in ripening fruit than in developing fruit and positively correlated with ethylene production in both cultivars. PbbHLH164 could directly bind to the promoter of 1-aminocyclopropane-1-carboxylate synthase, PbACS1b, to enhance the expression, leading to the increase of ethylene production and the acceleration of fruit ripening. Interestingly, PbbHLH164 physically interacted with an ubiquitin-like/ubiquitin-associated protein PbRAD23C/D.1, and the interaction of PbbHLH164 with PbRAD23C/D.1 attenuated the function of PbbHLH164 in enhancing the activity of the PbACS1b promoter. Notably, PbRAD23C/D.1 was involved in the degradation of PbbHLH164, and this degradation was inhibited by an ubiquitin proteasome inhibitor MG132. Different from PbbHLH164, PbRAD23C/D.1 was more highly expressed in developing fruit than in ripening fruit of both cultivars. These results suggest that the increase of ethylene production during pear fruit ripening results from the up-regulated expression of PbbHLH164 and the down-regulated expression of PbRAD23C/D.1. This information provided new insights into the molecular regulation of ethylene biosynthesis during fruit ripening.

A deep learning model for detection of leukocytes under various interference factors.

The accurate detection of leukocytes is the basis for the diagnosis of blood system diseases. However, diagnosing leukocyte disorders by doctors is time-consuming and requires extensive experience. Automated detection methods with high accuracy can improve detection efficiency and provide recommendations to inexperienced doctors. Current methods and instruments either fail to automate the identification process fully or have low performance and need suitable leukocyte data sets for further study. To improve the current status, we need to develop more intelligent strategies. This paper investigates fulfilling high-performance automatic detection for leukocytes using a deep learning-based method. We established a new dataset more suitable for leukocyte detection, containing 6273 images (8595 leukocytes) and considering nine common clinical interference factors. Based on the dataset, the performance evaluation of six mainstream detection models is carried out, and a more robust ensemble model is proposed. The mean of average precision (mAP) @IoU = 0.50:0.95 and mean of average recall (mAR)@IoU = 0.50:0.95 of the ensemble model on the test set are 0.853 and 0.922, respectively. The detection performance of poor-quality images is robust. For the first time, it is found that the ensemble model yields an accuracy of 98.84% for detecting incomplete leukocytes. In addition, we also compared the test results of different models and found multiple identical false detections of the models, then provided correct suggestions for the clinic.

A deep learning-based stripe self-correction method for stitched microscopic images.

Stitched fluorescence microscope images inevitably exist in various types of stripes or artifacts caused by uncertain factors such as optical devices or specimens, which severely affects the image quality and downstream quantitative analysis. Here, we present a deep learning-based Stripe Self-Correction method, so-called SSCOR. Specifically, we propose a proximity sampling scheme and adversarial reciprocal self-training paradigm that enable SSCOR to utilize stripe-free patches sampled from the stitched microscope image itself to correct their adjacent stripe patches. Comparing to off-the-shelf approaches, SSCOR can not only adaptively correct non-uniform, oblique, and grid stripes, but also remove scanning, bubble, and out-of-focus artifacts, achieving the state-of-the-art performance across different imaging conditions and modalities. Moreover, SSCOR does not require any physical parameter estimation, patch-wise manual annotation, or raw stitched information in the correction process. This provides an intelligent prior-free image restoration solution for microscopists or even microscope companies, thus ensuring more precise biomedical applications for researchers.

Exposure of Pseudomonas aeruginosa to green tea polyphenols enhances the tolerance to various environmental stresses.

Green tea polyphenols (GTP) are widely used as food preservatives and are considered to be extremely safe. However, the bacterial response to GTP has not been well studied. Here we investigated whether short exposure of Pseudomonas aeruginosa to sub-lethal dose of GTP could lead to cross-resistance to some environmental stresses. One-hour exposure of P. aeruginosa to 1 mg/ml GTP significantly increased the tolerance to oxidants (2 mM H(2)O(2), 4 mM tert-butylhydroperoxide), low pH solution (pH 4.0) containing various organic acids (60 mM citric, acetic, propionic or lactic acid) and other stress conditions (47 °C, 25 % NaCl, 12 % ethanol and 150 µg/ml crystal violet). The development of H(2)O(2) tolerance in GTP-exposed cells was prevented by chloramphenicol, a well-known inhibitor of protein synthesis in prokaryotic cells. Furthermore, we observed significantly increased catalase activity after GTP exposure, suggesting that P. aeruginosa develops GTP-induced cross-resistance by increasing synthesis of protective protein. These observations raise concerns over the underlying risks associated with using GTP as food preservatives.

GIU-GANs: Global Information Utilization for Generative Adversarial Networks.

Recently, with the rapid development of artificial intelligence, image generation based on deep learning has advanced significantly. Image generation based on Generative Adversarial Networks (GANs) is a promising study. However, because convolutions are limited by spatial-agnostic and channel-specific, features extracted by conventional GANs based on convolution are constrained. Therefore, GANs cannot capture in-depth details per image. Moreover, straightforwardly stacking of convolutions causes too many parameters and layers in GANs, yielding a high overfitting risk. To overcome the abovementioned limitations, in this study, we propose a GANs called GIU-GANs (where Global Information Utilization: GIU). GIU-GANs leverages a new module called the GIU module, which integrates the squeeze-and-excitation module and involution to focus on global information via the channel attention mechanism, enhancing the generated image quality. Moreover, Batch Normalization (BN) inevitably ignores the representation differences among noise sampled by the generator and thus degrades the generated image quality. Thus, we introduce the representative BN to the GANs' architecture. The CIFAR-10 and CelebA datasets are employed to demonstrate the effectiveness of the proposed model. Numerous experiments indicate that the proposed model achieves state-of-the-art performance.

Genes Involved in Biofilm Matrix Formation of the Food Spoiler Pseudomonas fluorescens PF07.

The extracellular matrix is essential for the biofilm formation of food spoilers. Pseudomonas fluorescens PF07 is a previous isolate from spoiled marine fish; however, the genes involved in the extracellular matrix formation of PF07 biofilms remain poorly defined. In this study, PF07 formed a wrinkled macrocolony biofilm through the high production of extracellular matrix. The genes involved in biofilm matrix formation and regulation were screened and identified by RNA-seq-dependent transcriptomic analysis and gene knock-out analysis. The macrocolony biofilms of PF07 grown for 5 days (PF07_5d) were compared with those grown for 1 day (PF07_1d). A total of 1,403 genes were significantly differentially expressed during biofilm formation. These mainly include the genes related to biofilm matrix proteins, polysaccharides, rhamnolipids, secretion system, biofilm regulation, and metabolism. Among them, functional amyloid genes fapABCDE were highly upregulated in the mature biofilm, and the operon fapA-E had a -24/-12 promoter dependent on the sigma factor RpoN. Moreover, the RNA-seq analyses of the rpoN mutant, compared with PF07, revealed 159 genes were differentially expressed in the macrocolony biofilms, and fapA-E genes were positively regulated by RpoN. In addition, the deletion mutants of fapC, rpoN, and brfA (a novel gene coding for an RpoN-dependent transcriptional regulator) were defective in forming mature macrocolony biofilms, solid surface-associated (SSA) biofilms, and pellicles, and they showed significantly reduced biofilm matrices. The fap genes were significantly downregulated in ΔbrfA, as in ΔrpoN. These findings suggest that the functional amyloid Fap is the main component of PF07 biofilm matrices, and RpoN may directly regulate the transcription of fap genes, in conjunction with BrfA. These genes may serve as potential molecular targets for screening new anti-biofilm agents or for biofilm detection in food environments.

Production of Prebiotic Xylooligosaccharides via Dilute Maleic Acid-Mediated Xylan Hydrolysis Using an RSM-Model-Based Optimization Strategy.

Xylooligosaccharides (XOS) are functional feed additives that are attracting growing commercial interest owing to their excellent ability to modulate the composition of the gut microbiota. The acid hydrolysis-based processing of xylan-containing materials has been proposed to represent a cost-effective approach to XOS preparation, with organic acids being preferable in this context. As such, in the present study, maleic acid was selected as a mild, edible organic acid for use in the hydrolysis of xylan to produce XOS. A response surface methodology (RSM) approach with a central composite design was employed to optimize maleic acid-mediated XOS production, resulting in a yield of 50.3% following a 15 min treatment with 0.08% maleic acid at 168°C. Under these conditions, the desired XOS degree of polymerization (2-3) was successfully achieved, demonstrating the viability of this using a low acid dose and a high reaction temperature to expedite the production of desired functional products. Moreover, as maleic acid is a relatively stable carboxylic acid, it has the potential to be recycled. These results suggest that dilute maleic acid-based thermal treatment of corncob-derived xylan can achieve satisfactory XOS yields, highlighting a promising and cost-effective approach to XOS production.

Uric Acid Predicts Recovery of Left Ventricular Function and Adverse Events in Heart Failure With Reduced Ejection Fraction: Potential Mechanistic Insight From Network Analyses.

Background and Aims: Heart failure with reduced ejection fraction (HFrEF) still carries a high risk for a sustained decrease in left ventricular ejection fraction (LVEF) even with the optimal medical therapy. Currently, there is no effective tool to stratify these patients according to their recovery potential. We tested the hypothesis that uric acid (UA) could predict recovery of LVEF and prognosis of HFrEF patients and attempted to explore mechanistic relationship between hyperuricemia and HFrEF. Methods: HFrEF patients with hyperuricemia were selected from the National Inpatient Sample (NIS) 2016-2018 database and our Xianyang prospective cohort study. Demographics, cardiac risk factors, and cardiovascular events were identified. Network-based analysis was utilized to examine the relationship between recovery of LVEF and hyperuricemia, and we further elucidated the underlying mechanisms for the impact of hyperuricemia on HFrEF. Results: After adjusting confounding factors by propensity score matching, hyperuricemia was a determinant of HFrEF [OR 1.247 (1.172-1.328); P < 0.001] of NIS dataset. In Xianyang prospective cohort study, hyperuricemia is a significant and independent risk factor for all-cause death (adjusted HR 2.387, 95% CI 1.141-4.993; P = 0.021), heart failure readmission (adjusted HR 1.848, 95% CI 1.048-3.259; P = 0.034), and composite events (adjusted HR 1.706, 95% CI 1.001-2.906; P = 0.049) in HFrEF patients. UA value at baseline was negatively correlated to LVEF of follow-ups (r = -0.19; P = 0.046). Cutoff UA value of 312.5 µmmol/L at baseline can work as a predictor of LVEF recovery during follow-up, with the sensitivity of 66.7%, the specificity of 35.1%, and the accuracy of 0.668 (95% CI, 0.561-0.775; P = 0.006). Moreover, gene overlap analysis and network proximity analysis demonstrated a strong correlation between HFrEF and Hyperuricemia. Conclusion: Lower baseline UA value predicted the LVEF recovery and less long-term adverse events in HFrEF patients. Our results provide new insights into underlying mechanistic relationship between hyperuricemia and HFrEF.