Relationship between biofilm formation and antibiotic resistance of Klebsiella pneumoniae and updates on antibiofilm therapeutic strategies.

Klebsiella pneumoniae is a Gram-negative bacterium within the Enterobacteriaceae family that can cause multiple systemic infections, such as respiratory, blood, liver abscesses and urinary systems. Antibiotic resistance is a global health threat and K. pneumoniae warrants special attention due to its resistance to most modern day antibiotics. Biofilm formation is a critical obstruction that enhances the antibiotic resistance of K. pneumoniae. However, knowledge on the molecular mechanisms of biofilm formation and its relation with antibiotic resistance in K. pneumoniae is limited. Understanding the molecular mechanisms of biofilm formation and its correlation with antibiotic resistance is crucial for providing insight for the design of new drugs to control and treat biofilm-related infections. In this review, we summarize recent advances in genes contributing to the biofilm formation of K. pneumoniae, new progress on the relationship between biofilm formation and antibiotic resistance, and new therapeutic strategies targeting biofilms. Finally, we discuss future research directions that target biofilm formation and antibiotic resistance of this priority pathogen.

Efficacy and safety of traditional Chinese patent medicine on carotid artery atherosclerosis in adults: A network meta-analysis protocol.

BACKGROUND: Atherosclerosis (AS), the predominant pathological basis of ischemic cardiovascular and cerebrovascular diseases, remains a common and severe clinical problem. The experiments in vitro and in vivo indicate that Traditional Chinese patent medicine (TCPM) shows beneficial efficacy against AS through a variety of mechanisms. However, the existing therapeutic TCPM for the treatment of AS are diverse, and it is still significant to evaluate the pros and cons of a certain TCPM. Therefore, the study aims to compare the efficacy and outcomes of different anti-atherosclerotic TCPM in adults with the hope of providing references for clinical decision making. METHODS: Cochrane Library, PubMed, Embase, Web of Science, China National Knowledge Infrastructure Database, Wanfang Database, Chinese BioMedical Literature Database, and China Science and Technology Journal Database will be searched. Randomized controlled trials (RCTs) of TCPM for aortic AS in adults will be included in this study if they meet the Population/Intervention/Comparison/Outcomes/Study Design (PICOS) criteria. Two reviewers will independently perform citations screening, data extraction and risk of bias assessment. STATA 15.0 and WinBUGS 1.4.3 will be employed to conduct statistical analyses under the Bayesian framework. RESULTS: The efficacy and safety of various TCPM strategies on aortic AS in adults will be compared. CONCLUSION: The study will expand the range of options for anti-atherosclerotic therapeutic strategies and encourages further clinical research in traditional Chinese medicine. INPLASY REGISTRATION NUMBER: INPLASY2020120036.

EARLY VITAMIN A SUPPLEMENTATION IMPROVES THE OUTCOME OF RETINOPATHY OF PREMATURITY IN EXTREMELY PRETERM INFANTS.

PURPOSE: This study assessed the efficacy and safety of early vitamin A (VA) supplementation to improve outcomes of retinopathy of prematurity in extremely preterm infants. METHODS: A total of 262 eligible extremely preterm infants underwent randomization; of these, 132 were assigned to the VA group and 130 to the control group. The infants were administered a solution of VA (1,500 IU/day), added to their enteral feeds as soon as minimal feeding was introduced and continued for 28 days or until discharge. RESULTS: With no adverse effects occurring, serum VA of the VA-supplemented infants on Days 14, 28, and postmenstrual 36 weeks was higher than that of the placebo group (P < 0.001). No signs of VA toxicity or increased intracranial pressure were reported. The VA group had lower unadjusted rates of Type 1 retinopathy of prematurity (1.6 vs. 6.9%, P = 0.030) and bronchopulmonary dysplasia (18.9 vs. 33.8%, P = 0.008) than the control group. Regression analysis revealed an association between serum VA levels and risk of Type 1 retinopathy of prematurity (beta = -2.37). CONCLUSION: Vitamin A supplementation reduced VA deficiency in extremely preterm infants; it was associated with a decreased incidence of Type 1 retinopathy of prematurity and may also have a positive impact on reducing bronchopulmonary dysplasia.

Structural characterisation and ACE-inhibitory activities of polysaccharide from Gastrodia elata Blume.

The structural properties and Angiotensin-I converting enzyme (ACE) inhibition activities of a polysaccharide (PGE) extracted from Gastrodia elata Blume were investigated. PGE was extracted using hot water and purified by Sephadex G-200 followed by ultra-filtration. The structural characterisation of PGE was analysed by FT-IR, NMR spectroscopy, specific rotation determination, periodate oxidation-smith degradation, methylation analysis, GC-MS and Congo red test. The results revealed that PGE was composed by glucose, with an average molecular weight of 1.54 × 103 kDa. The structure of PGE was 1→3 and 1→4,6-branched-glucopyranose that had a linear backbone of (1 → 4)-linked-d-glucopyranose (Glcp). ACE-inhibitory activity results showed that PGE was efficient to inhibit ACE and the IC50 value was 0.66 mg/mL.

Structure analysis and anti-fatigue activity of a polysaccharide from Lepidium meyenii Walp.

A polysaccharide was obtained from Lepidium meyenii Walp by hot water extraction and purification by Millipore (100 kD) and Sephadex G-200. The content of polysaccharide was examined to be 89.9% with phenol-sulfuric acid method. Its average molecular weight was estimated to be 2.213 × 106 Da by High Performance Gel Permeation Chromatography (HPGPC). Monosaccharide analysis showed that the polysaccharide was composed of arabinose, mannose, glucose and galactose with the molar ratio of 2.134: 1: 2.78: 2.82. After Smith degradation, methylation, infrared spectroscopy and NMR, the primary structure of the polysaccharide was identified. The backbone of the polysaccharide was composed of →4)-ß-D-Galp-(1→ and →4)-α-D-Galp-(1→, while the branches were comprised of →6)-ß-D-Glup-(1→, →5)- ß-D-Araf-(1→, →3,6)-α-D-Manp-(1→, →3)-α-D-Galp-(1→, and α-D-Glup-(1→. The anti-fatigue effect of the polysaccharide was evaluated using exhaustive swimming test and biochemical indexes. The results indicated the polysaccharide has anti-fatigue effect.

Structural characterization and antitumor activity of a novel Se-polysaccharide from selenium-enriched Cordyceps gunnii.

Selenium (Se) has been recognized as an essential element. Animals and humans absorb and retain more organic Se than inorganic Se. Bio-transformation is a major approach to transform inorganic Se to organic Se. Cordyceps gunnii (C. gunnii), well known as a Chinese edible and medicinal fungus, has a variety of biological functions. C. gunnii and selenium were combined through liquid-fermentation to obtain selenium-enriched C. gunnii. A novel Se-polysaccharide (SeCPS-II) was extracted from selenium-enriched C. gunnii. The molecular weight, sugar content and selenium content of SeCPS-II were 4.12 × 103 kDa, 17.89 µg g-1 and 90.75%, respectively. The structure of SeCPS-II was characterized using FT-IR, NMR, GC and GC-MS studies. SeCPS-II was composed of pyranose, which contained α-l-rhamnose, α-d-mannose, α-d-glucose and ß-d-galactose at a ratio of 4.33 : 12.62 : 27.50 : 18.99. SeCPS-II contained α-(1 → 4)-d-glucose, α-(1 → 3)-d-glucose, ß-(1 → 6)-d-galactose, α-(1 → 6)-d-mannose, and α-(1 → 4)-l-rhamnose, and the main chain was composed of α-(1 → 4)-d-glucose. An MTT assay indicated that SeCPS-II could influence the cell viability of SKOV-3 cells, H1299 cells and HepG2 cells in a dose-dependent and time-dependent manner. Morphologic changes (AO/EB staining and DAPI staining) and an MMP assay (JC-1 staining) of SKOV-3 cells treated with SeCPS-II were performed to research the antitumor activity of SeCPS-II. SeCPS-II could significantly induce apoptosis in SKOV-3 cells with typical apoptotic characteristics. To study the mechanism, the expressions of caspase-3, caspase-9, PARP, p53, Bax and Bcl-2 in SKOV-3 were studied via western blotting. SeCPS-II can stimulate the apoptosis of SKOV-3 cells through the p53-Bax-caspase pathway. Animal experiments revealed that SeCPS-II inhibits tumors within an ovarian tumor model rat, modeled with SKOV-3 cells. All the results indicated that selenium-enriched C. gunnii can be used to develop new selenium-containing additives.

The chemical structure and anti-aging bioactivity of an acid polysaccharide obtained from rose buds.

An acid polysaccharide, named R-PL, was extracted from rose buds by hot water (80 °C) extraction and purified by Sephadex G-200. R-PL, extracted with a total yield of 1.90%, is a highly pure polysaccharide with a total sugar content of 92.51%. A single and symmetrically sharp peak in its high-performance gel-permeation chromatography (HPGPC) spectrum indicates that R-PL is a homogeneous polysaccharide with a molecular weight of 7.727 × 105 Da. Monosaccharide composition analysis shows that it consists of d-arabinose, d-xylose, d-glucose, d-galactose, d-galacturonic acid, and d-glucuronic acid with a molar ratio of 4.6 : 1.4 : 5.22 : 4.81 : 1 : 1.86. Structure analysis, such as FTIR spectroscopy, periodic acid oxidation, Smith degradation, methylation, and NMR analysis, reveals that R-PL has a backbone of →1)-α-d-Glcp-(6→ with side chains of →1)-ß-d-Galp-(4,6→, →1)-ß-d-Araf-(5→, →1)-α-d-Xylp-(4→, →1)-α-d-GlcpA-(2→ and →1)-α-d-GalpA-(4→. Its morphological characteristics were identified by Congo red experiments and scanning electron microscopy (SEM) analysis. The results show that R-PL does not have a triple-helical conformation in solution; its shape resembles twisted ribbons. Anti-oxidative and anti-aging analyses show that R-PL has significant antioxidant and anti-aging abilities in vivo.

Synthesis, characterization and antioxidant activity of selenium polysaccharide from Cordyceps militaris.

A purified selenium-containing derivatives of Cordyceps militaris polysaccharide synthesized using H2SeO3/HNO3 and BaCl2 as a catalyst was investigated in this paper. The reaction condition was optimized by selecting different reaction temperature and period. Afterward, the one with the highest Se content was purified by ultra-filtration device with a molecular cut off size of 10KDa. Followed by its structural characterizations. Results of IFR and 13C NMR spectroscopy indicated that C-6 substitution was predominant in selenized polysaccharide. The modified polysaccharide with molecular weight of 1998 KDa was mainly consisted of mannose, glucose and galactose in the mole ratios of with the mole ratios of 1:28.63:1.41. Thermogravimetric and morphological analyses of the samples were carried out by AFS, SEM and AFM. In addition, the in vitro antioxidant results suggested that selenium-containing polysaccharide should be applied as a novel selenium source in dietary supplements, with potent antioxidant properties.

Structural characterization and inhibition on α-d-glucosidase activity of non-starch polysaccharides from Fagopyrum tartaricum.

In the present study, the crude polysaccharide was extracted from Fagopyrum tartaricum and purified by Sephadex G-25 and G-75 column to produce a polysaccharide fraction termed TBP-II. Its average molecular weight was 26kDa. The structural characterization of TBP-II was investigated by gas chromatography, periodate oxidation-Smith degradation, Methylation and NMR. Congo red was applied to explore its advanced structures. The results revealed that chemical composition and structural characteristic of TBP-II was mainly consisted of galactose, arabinose, xylose and glucose with a molar ratio of 0.7:1:6.3:74.2. The backbone of TBP-II was composed of (1→4)-linked α-d-glucopyranosyl (Glcp), while the branches comprised of (1→3)-linked α-d-glucopyranosyl (Glcp), (1→6)-linked α-d-galactopyranosyl (Galp) and (1→2,4)-linked α-d-rhamnopyranosyl (Rhap). The structure of TBP-II was 1,3 and 1,6-branched-galactorhamnoglucan that had a linear backbone of (1→4)-linked α-d-glucopyranose (Glcp). Using Congo red assay showed that it was absent of triple helix structure. The α-d-glucosidase inhibitory activity of TBP-II was determined using acarbose as positive control. The result showed that the inhibition rate depended on the concentration of polysaccharides.

Preparation and activity evaluation of chrysin-ß-D-galactopyranoside.

Chrysin-ß-D-galactopyranoside was efficiently synthesized, evaluated for its inhibitory activities against H22 cell lines compared with chrysin, the scavenging of hydroxyl radical, DPPH radical and superoxide anion, inhibitory effect against bacteria and fungi. The structures of all compounds were fully characterized by spectroscopic data (NMR, MS). The anti-tumor, antioxidant and antimicrobial activities of chrysin-ß-D-galactopyranoside were proved to be enhanced significantly compared with chrysin.