Identification of the Microbial Transformation Products of Secoisolariciresinol Using an Untargeted Metabolomics Approach and Evaluation of the Osteogenic Activities of the Metabolites.

Secoisolariciresinol (SECO) is one of the major lignans occurring in various grains, seeds, fruits, and vegetables. The gut microbiota plays an important role in the biotransformation of dietary lignans into enterolignans, which might exhibit more potent bioactivities than the precursor lignans. This study aimed to identify, synthesize, and evaluate the microbial metabolites of SECO and to develop efficient lead compounds from the metabolites for the treatment of osteoporosis. SECO was fermented with human gut microbiota in anaerobic or micro-aerobic environments at different time points. Samples derived from microbial transformation were analyzed using an untargeted metabolomics approach for metabolite identification. Nine metabolites were identified and synthesized. Their effects on cell viability, osteoblastic differentiation, and gene expression were examined. The results showed that five of the microbial metabolites exerted potential osteogenic effects similar to those of SECO or better. The results suggested that the enterolignans might account for the osteoporotic effects of SECO in vivo. Thus, the presence of the gut microbiota could offer a good way to form diverse enterolignans with bone-protective effects. The current study improves our understanding of the microbial transformation products of SECO and provides new approaches for new candidate identification in the treatment of osteoporosis.

Structural and Functional Characterization of OXA-48: Insight into Mechanism and Structural Basis of Substrate Recognition and Specificity.

Class D ß-lactamase OXA-48 is widely distributed among Gram-negative bacteria and is an important determinant of resistance to the last-resort carbapenems. Nevertheless, the detailed mechanism by which this ß-lactamase hydrolyzes its substrates remains poorly understood. In this study, the complex structures of OXA-48 and various ß-lactams were modeled and the potential active site residues that may interact with various ß-lactams were identified and characterized to elucidate their roles in OXA-48 substrate recognition. Four residues, namely S70, K73, S118, and K208 were found to be essential for OXA-48 to undergo catalytic hydrolysis of various penicillins and carbapenems both in vivo and in vitro. T209 was found to be important for hydrolysis of imipenem, whereas R250 played a major role in hydrolyzing ampicillin, imipenem, and meropenem most likely by forming a H-bond or salt-bridge between the side chain of these two residues and the carboxylate oxygen ions of the substrates. Analysis of the effect of substitution of alanine in two residues, W105 and L158, revealed their roles in mediating the activity of OXA-48. Our data show that these residues most likely undergo hydrophobic interaction with the R groups and the core structure of the ß-lactam ring in penicillins and the carbapenems, respectively. Unlike OXA-58, mass spectrometry suggested a loss of the C6-hydroxyethyl group during hydrolysis of meropenem by OXA-48, which has never been demonstrated in Class D carbapenemases. Findings in this study provide comprehensive knowledge of the mechanism of the substrate recognition and catalysis of OXA-type ß-lactamases.

Comparative Characterization of CTX-M-64 and CTX-M-14 Provides Insights into the Structure and Catalytic Activity of the CTX-M Class of Enzymes.

Clinical isolates producing hybrid CTX-M ß-lactamases, presumably due to recombination between the blaCTX-M-15 and blaCTX-M-14 elements, have emerged in recent years. Among the hybrid enzymes, CTX-M-64 and CTX-M-14 display the most significant difference in catalytic activity. This study aims to investigate the mechanisms underlying such differential enzymatic activities in order to provide insight into the structure/function relationship of this class of enzymes. Sequence alignment analysis showed that the major differences between the amino acid composition of CTX-M-64 and CTX-M-14 lie at both the N and C termini of the enzymes. Single or multiple amino acid substitutions introduced into CTX-M-64 and CTX-M-14 were found to produce only minor effects on hydrolytic functions; such a finding is consistent with the notion that the discrepancy between the functional activities of the two enzymes is not the result of only a few amino acid changes but is attributable to interactions between a unique set of amino acid residues in each enzyme. This theory is supported by the results of the thermal stability assay, which confirmed that CTX-M-64 is significantly more stable than CTX-M-14. Our data confirmed that, in addition to the important residues located in the active site, residues distal to the active site also contribute to the catalytic activity of the enzyme through stabilizing its structural integrity.

CARB-17 family of ß-lactamases mediates intrinsic resistance to penicillins in Vibrio parahaemolyticus.

Vibrio parahaemolyticus is commonly resistant to ampicillin, yet the mechanisms underlying this phenomenon are not clear. In this study, a novel class A carbenicillin-hydrolyzing ß-lactamase (CARB) family of ß-lactamases, bla(CARB-17), was identified and found to be responsible for the intrinsic penicillin resistance in V. parahaemolyticus. Importantly, bla(CARB-17)-like genes were present in all 293 V. parahaemolyticus genome sequences available in GenBank and detectable in all 91 V. parahaemolyticus food isolates, further confirming the intrinsic nature of this gene.

Residues Distal to the Active Site Contribute to Enhanced Catalytic Activity of Variant and Hybrid ß-Lactamases Derived from CTX-M-14 and CTX-M-15.

A variety of CTX-M-type extended-spectrum ß-lactamases (ESBLs), including hybrid ones, have been reported in China that are uncommon elsewhere. To better characterize the substrate profiles and enzymatic mechanisms of these enzymes, we performed comparative kinetic analyses of both parental and hybrid CTX-M enzymes, including CTX-M-15, -132, -123, -64, -14 and -55, that are known to confer variable levels of ß-lactam resistance in the host strains. All tested enzymes were susceptible to serine ß-lactamase inhibitors, with sulbactam exhibiting the weakest inhibitory effects. CTX-M-55, which differs from CTX-M-15 by one substitution, A(77)V, displayed enhanced catalytic activity (kcat/Km) against expanded-spectrum cephalosporins (ESCs). CTX-M-55 exhibits higher structure stability, most likely by forming hydrophobic interactions between A(77)V and various key residues in different helices, thereby stabilizing the core architecture of the helix cluster, and indirectly contributes to a more stable active site conformation, which in turn shows higher catalytic efficiency and is more tolerant to temperature change. Analyses of the hybrids and their parental prototypes showed that evolution from CTX-M-15 to CTX-M-132, CTX-M-123, and CTX-M-64, characterized by gradual enhancement of catalytic activity to ESCs, was attributed to introduction of different substitutions to amino acids distal to the active site of CTX-M-15. Similarly, the increased hydrolytic activities against cephalosporins and sensitivity to ß-lactamase inhibitors, clavulanic acid and sulbactam, of CTX-M-64 were partly due to the amino acids that were different from CTX-M-14 and located at both the C and N termini of CTX-M-64. These data indicate that residues distal to the active site of CTX-Ms contributed to their enhanced catalytic activities to ESCs.

Molecular mechanisms of substrate recognition and specificity of New Delhi metallo-ß-lactamase.

Carbapenems are one of the last lines of defense for Gram-negative pathogens, such as members of the Enterobacteriaceae. Despite the fact that most carbapenems are resistant to extended-spectrum ß-lactamase (ESBL), emerging metallo-ß-lactamases (MBLs), including New Delhi metallo-ß-lactamase 1 (NDM-1), that can hydrolyze carbapenems have become prevalent and are frequently associated with the so-called "superbugs," for which treatments are extremely limited. Crystallographic study sheds light on the modes of antibiotic binding to NDM-1, yet the mechanisms governing substrate recognition and specificity are largely unclear. This study provides a connection between crystallographic study and the functional significance of NDM-1, with an emphasis on the substrate specificity and catalysis of various ß-lactams. L1 loop residues L59, V67, and W87 were important for the activity of NDM-1, most likely through maintaining the partial folding of the L1 loop or active site conformation through hydrophobic interaction with the R groups of ß-lactams or the ß-lactam ring. Substitution of alanine for L59 showed greater reduction of MICs to ampicillin and selected cephalosporins, whereas substitutions of alanine for V67 had more impact on the MICs of carbapenems. K224 and N233 on the L3 loop played important roles in the recognition of substrate and contributed to substrate hydrolysis. These data together with the structure comparison of the B1 and B2 subclasses of MBLs revealed that the broad substrate specificity of NDM-1 could be due to the ability of its wide active site cavity to accommodate a wide range of ß-lactams. This study provides insights into the development of efficient inhibitors for NDM-1 and offers an efficient tactic with which to study the substrate specificities of other ß-lactamases.

Antiviral and Antibacterial 3D-Printed Products Functionalised with Poly(hexamethylene biguanide).

Infection prevention and public health are a vital concern worldwide, especially during pandemics such as COVID-19 and seasonal influenza. Frequent manual disinfection and use of chemical spray coatings at public facilities are the typical measures taken to protect people from coronaviruses and other pathogens. However, limitations of human resources and coating durability, as well as the safety of disinfectants used are the major concerns in society during a pandemic. Non-leachable antimicrobial agent poly(hexamethylene biguanide) (PHMB) was mixed into photocurable liquid resins to produce novel and tailor-made covers for public facilities via digital light processing, which is a popular 3D printing technique for satisfactory printing resolution. Potent efficacies of the 3D-printed plastics were achieved in standard antibacterial assessments against S. aureus, E. coli and K. pneumoniae. A total of 99.9% of Human coronavirus 229E was killed after being in contact with the 3D-printed samples (containing the promising PHMB formulation) for two hours. In an eight-week field test in Hong Kong Wetland Park, antibacterial performances of the specially designed 3D-printed covers analysed by environmental swabbing were also found to be satisfactory. With these remarkable outcomes, antimicrobial products prepared by digital light processing 3D printing can be regarded as a reliable solution to long-term infection prevention and control.

Development of a quantitative RT-PCR assay to examine the kinetics of ribosome depurination by ribosome inactivating proteins using Saccharomyces cerevisiae as a model.

Ricin produced by the castor bean plant and Shiga toxins produced by pathogenic Escherichia coli (STEC) and Shigella dysenteriae are type II ribosome inactivating proteins (RIPs), containing an enzymatically active A subunit that inhibits protein synthesis by removing an adenine from the α-sarcin/ricin loop (SRL) of the 28S rRNA. There are currently no known antidotes to Shiga toxin or ricin, and the ability to screen large chemical libraries for inhibitors has been hindered by lack of quantitative assays for catalytic activity that can be adapted to a high throughput format. Here, we describe the development of a robust and quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay that can directly measure the toxins' catalytic activity on ribosomes and can be used to examine the kinetics of depurination in vivo. The qRT-PCR assay exhibited a much wider dynamic range than the previously used primer extension assay (500-fold vs. 16-fold) and increased sensitivity (60 pM vs. 0.57 nM). Using this assay, a 400-fold increase in ribosome depurination was observed in yeast expressing ricin A chain (RTA) relative to uninduced cells. Pteroic acid, a known inhibitor of enzymatic activity, inhibited ribosome depurination by RTA and Shiga toxin 2 with an IC(50) of ∼ 100 µM, while inhibitors of ricin transport failed to inhibit catalytic activity. These results demonstrate that the qRT-PCR assay would enable refined kinetic studies with RIPs and could be a powerful screening tool to identify inhibitors of catalytic activity.

Impact of Plasticizer on the Intestinal Epithelial Integrity and Tissue-Repairing Ability within Cells in the Proximity of the Human Gut Microbiome.

Toxicological research into the impact of plasticizer on different organs has been reported in the past few decades, while their effects on shifting the gut microbiota and immune cells homeostasis in zebrafish were only studied recently. However, studies on the impact of plasticizer on human gut microbiota are scarce. In this study, we co-incubated healthy human fecal microbiota with different concentrations of Di(2-ethylhexyl) phthalate (DEHP) and di-iso-nonyl phthalate (DINP), analyzed microbial composition by 16S rDNA sequencing, and compared the influence of their derived microbiomes on the human enterocyte (HT-29) and murine macrophage (RAW264.7) cell lines. Microbial diversity is reduced by DEHP treatment in a dose-dependent manner. DEHP treatment reduced the phyla Firmicutes/Bacteroidetes ratio, while DINP treatment promoted Proteobacteria. Expressions of tight/adherens junction genes in HT-29 and anti-inflammatory genes in RAW264.7 were down-regulated by plasticizer-co-incubated microbiota derived metabolites. Overall, it is observed that selected plasticizers at high dosages can induce compositional changes in human microbiota. Metabolites from such altered microbiota could affect the tight junction integrity of the intestinal epithelium and upset macrophage differentiation homeostasis in proximity. Chronic exposure to these plasticizers may promote risks of dysbiosis, leaky gut or the exacerbation of intestinal inflammation.

Prolonged High-Fat Diet Consumption throughout Adulthood in Mice Induced Neurobehavioral Deterioration via Gut-Brain Axis.

Neuropsychiatric disorders have been one of the worldwide health problems contributing to profound social and economic consequences. It is reported that consumption of an excessive high-fat diet (HFD) in middle age could induce cognitive and emotional dysfunctions, whereas the mechanisms of the effects of long-term HFD intake on brain disorders have not been fully investigated. We propose a hypothesis that prolonged HFD intake throughout adulthood could lead to neurobehavioral deterioration via gut-brain axis. In this study, the adult C57BL/6J mice consuming long-term HFD (24 weeks) exhibited more anxiety-like, depression-like, and disruptive social behaviors and poorer performance in learning and memory than control mice fed with a normal diet (ND). In addition, the homeostasis of gut microbiota was impaired by long-term HFD consumption. Changes in some flora, such as Prevotellaceae_NK3B31_group and Ruminococcus, within the gut communities, were correlated to neurobehavioral alterations. Furthermore, the gut permeability was increased after prolonged HFD intake due to the decreased thickness of the mucus layer and reduced expression of tight junction proteins in the colon. The mRNA levels of genes related to synaptic-plasticity, neuronal development, microglia maturation, and activation in the hippocampus and prefrontal cortex of HFD-fed mice were lower than those in mice fed with ND. Interestingly, the transcripts of genes related to tight junction proteins, ZO-1 and Occludin involved in blood-brain-barrier (BBB), were decreased in both hippocampus and prefrontal cortex after long-term HFD consumption. Those results indicated that chronic consumption of HFD in mice resulted in gut microbiota dysbiosis, which induced decreased expression of mucus and tight junction proteins in the colon, in turn leading to local and systemic inflammation. Those changes could further contribute to the impairment of brain functions and neurobehavioral alterations, including mood, sociability, learning and memory. In short, long-term HFD intake throughout adulthood could induce behavioral phenotypes related to neuropsychiatric disorders via gut-brain axis. The observations of this study provide potential intervention strategies to reduce the risk of HFD via targeting the gut or manipulating gut microbiota.

Structural characteristics and in vitro fermentation patterns of polysaccharides from Boletus mushrooms.

The aim of this study was to investigate the structural characteristics and in vitro fermentation patterns of polysaccharides from Boletus mushrooms. Polysaccharides were solubilized from fruit bodies of selected mushrooms Boletus auripes, B. bicolor, and B. griseus using subcritical water extraction. Boletus polysaccharides were characterized for their general physicochemical pattern, constituent monosaccharides and molecular weight. A simulated in vitro fermentation model was used to study the utilization of Boletus polysaccharides by the gut microbiota and their consequent modulation of microbial communities. Results showed that the main constituent monosaccharides of Boletus polysaccharides were glucose, galactose and mannose, followed by fucose, xylose and rhamnose, with glucose being the most abundant. The polysaccharides from B. bicolor and B. griseus exhibited a relatively high proportion of galactose and mannose, respectively. Boletus polysaccharides exhibited a wide range of molecular weights (5 kDa to 2000 kDa), which covered multiple polysaccharide populations, but the proportions of these populations varied among the samples. Boletus polysaccharides were gradually utilized by the human fecal microbiota, promoting the production of SCFAs. Boletus polysaccharides contributed to a healthier gut microbiota composition by increasing the relative abundance of beneficial bacterial genera such as Bacteroides and Faecalibacterium and reducing the relative abundance of harmful bacterial genera such as Sutterella and Escherichia-Shigella. B. bicolor polysaccharides showed better fermentability and prebiotic effects than the other Boletus polysaccharide groups. Therefore, the consumption of select Boletus mushrooms, particularly B. bicolor, could be a potential approach to obtain polysaccharides for microbiota modulation and to support gut health.

Alfalfa as a vegetable source of ß-carotene: The change mechanism of ß-carotene during fermentation.

The objectives of this study were to explore the ß-carotene-producing bacteria and ascertain the main factors affecting ß-carotene content via investigating the effects of various additives on ß-carotene content, bacterial community succession, and quality of fermented alfalfa, using single-molecule real-time (SMRT) sequencing technology. Fresh alfalfa was fermented without (CON) or with squalene (SQ), the combination of Lactobacillus plantarum and cellulase (LPEN), and the combination of SQ and LPEN (SQLPEN) for 3, 45, and 90 d. The results showed that relative to the fresh alfalfa, extensive ß-carotene loss in all groups occurred in the early fermentation phase (3 d) since epiphytic Pantoea agglomerans with the ability to produce ß-carotene disappeared and ß-carotene was oxidized by lipoxygenase and peroxidase. With the prolonged fermentation days, ß-carotene content in all groups increased due to bacterial community succession in the middle and late phases of fermentation (45 and 90 d). The species L. parabuchneri, L. kunkeei, and L. kullabergensis (r = 0.591, 0.366, 0.341, orderly) had positive correlations with ß-carotene content (P < 0.05). Bacterial functional potential prediction showed that species L. kunkeei, L. helsingborgensis, and L. kullabergensis had positive (r = 0.478, 0.765, 0.601) correlations with C10-C20 isoprenoid biosynthesis (P < 0.01), and L. helsingborgensis and L. kullabergensis had positive (r = 0.805, 0.522) correlations with ß-carotene biosynthesis (P < 0.01). Additionally, the pH and propionic acid (r = -0.567, -0.504) had negative correlations with ß-carotene content (P < 0.01). The CON group was preserved well after 90 d, LPEN and SQLPEN further improved fermentation quality. In conclusion, certain Lactobacillus had the potential for ß-carotene biosynthesis, and high pH and propionic acid content were the unbenefited factors for ß-carotene retention in fermented alfalfa.

The clinical characteristics of pediatric patients infected by SARS-CoV-2 Omicron variant and whole viral genome sequencing analysis.

Pediatric population was generally less affected clinically by SARS-CoV-2 infection. Few pediatric cases of COVID-19 have been reported compared to those reported in infected adults. However, a rapid increase in the hospitalization rate of SARS-CoV-2 infected pediatric patients was observed during Omicron variant dominated COVID-19 outbreak. In this study, we analyzed the B.1.1.529 (Omicron) genome sequences collected from pediatric patients by whole viral genome amplicon sequencing using Illumina next generation sequencing platform, followed by phylogenetic analysis. The demographic, epidemiologic and clinical data of these pediatric patients are also reported in this study. Fever, cough, running nose, sore throat and vomiting were the more commonly reported symptoms in children infected by Omicron variant. A novel frameshift mutation was found in the ORF1b region (NSP12) of the genome of Omicron variant. Seven mutations were identified in the target regions of the WHO listed SARS-CoV-2 primers and probes. On protein level, eighty-three amino acid substitutions and fifteen amino acid deletions were identified. Our results indicate that asymptomatic infection and transmission among children infected by Omicron subvariants BA.2.2 and BA.2.10.1 are not common. Omicron may have different pathogenesis in pediatric population.

Elucidation of Anti-Hypertensive Mechanism by a Novel Lactobacillus rhamnosus AC1 Fermented Soymilk in the Deoxycorticosterone Acetate-Salt Hypertensive Rats.

Dietary intake of fermented soymilk is associated with hypotensive effects, but the mechanisms involved have not been fully elucidated. We investigated the anti-hypertensive effects of soymilk fermented by L. rhamnosus AC1 on DOCA-salt hypertension from the point of view of oxidative stress, inflammatory response and alteration of the gut microbiome. The antioxidant assays in vitro indicated the ethanol extract (EE) of L. rhamnosus AC1 fermented soymilk showed better antioxidative effects than the water extract (WE). Those extracts displayed a hypotensive effect using a tail-cuff approach to measuring blood pressure and improved nitric oxide (NO), angiotensin II (Ang II), tumor necrosis factor-α (TNF-α) and interleukin factor-6 (IL-6) on DOCA-salt hypertensive rats. Furthermore, cardiac and renal fibrosis were attenuated by those extracts. The gut microbiota analysis revealed that they significantly reduced the abundance of phylum Proteobacteria, its family Enterobacteriaceae and genus Escherichia-Shigella. Moreover, metabolomic profiling revealed several potential gut microbiota-related metabolites which appeared to involve in the development and recovery of hypertension. In conclusion, fermented soymilk is a promising nutritional intervention strategy to improve hypertension via reducing inflammation and reverting dysbiotic microbiota.

Hypotensive effect of captopril on deoxycorticosterone acetate-salt-induced hypertensive rat is associated with gut microbiota alteration.

The role of the gut microbiota in various metabolic diseases has been widely studied. This study aims to test the hypothesis that gut microbiota dysbiosis is associated with DOCA-salt-induced hypertension, while captopril, an antihypertensive drug, is able to rebalance the gut microbiota alterations caused by hypertension. Treatment with captopril resulted in an approximate 32 mmHg reduction in systolic blood pressure (162.57 vs. 194.61 mmHg) in DOCA-salt-induced hypertensive rats, although it was significantly higher than that in SHAM rats (136.10 mmHg). Moreover, the nitric oxide (NO) level was significantly increased (20.60 vs. 6.42 µM) while the angiotensin II (Ang II) content (42.40 vs. 59.47 pg/ml) was attenuated nonsignificantly by captopril treatment in comparison to those of DOCA-salt-induced hypertensive rats. The introduction of captopril significantly decreased the levels of tumor necrosis factor-α (TNF-ɑ) and interleukin-6 (IL-6). Hypertrophy and fibrosis in kidneys and hearts were also significantly attenuated by captopril. Furthermore, gut microbiota dysbiosis was observed in DOCA-salt-induced hypertensive rats. The abundances of several phyla and genera, including Proteobacteria, Cyanobacteria, Escherichia-Shigella, Eubacterium nodatum and Ruminococcus, were higher in DOCA-salt-induced hypertensive rats than in SHAM rats, while these changes were reversed by captopril treatment. Of particular interest, the genera Bifidobacterium and Akkermansia, reported as beneficial bacteria in the gut, were abundant in only hypertensive rats treated with captopril. These results provide evidence that captopril has the potential to rebalance the dysbiotic gut microbiota of DOCA-salt-induced hypertensive rats, suggesting that the alteration of the gut flora by captopril may contribute to the hypotensive effect of this drug.

Captopril Alleviates Chondrocyte Senescence in DOCA-Salt Hypertensive Rats Associated with Gut Microbiome Alteration.

Gut microbiota is the key controller of healthy aging. Hypertension and osteoarthritis (OA) are two frequently co-existing age-related pathologies in older adults. Both are associated with gut microbiota dysbiosis. Hereby, we explore gut microbiome alteration in the Deoxycorticosterone acetate (DOCA)-induced hypertensive rat model. Captopril, an anti-hypertensive medicine, was chosen to attenuate joint damage. Knee joints were harvested for radiological and histological examination; meanwhile, fecal samples were collected for 16S rRNA and shotgun sequencing. The 16S rRNA data was annotated using Qiime 2 v2019.10, while metagenomic data was functionally profiled with HUMAnN 2.0 database. Differential abundance analyses were adopted to identify the significant bacterial genera and pathways from the gut microbiota. DOCA-induced hypertension induced p16INK4a+ senescent cells (SnCs) accumulation not only in the aorta and kidney (p < 0.05) but also knee joint, which contributed to articular cartilage degradation and subchondral bone disturbance. Captopril removed the p16INK4a + SnCs from different organs, partially lowered blood pressure, and mitigated cartilage damage. Meanwhile, these alterations were found to associate with the reduction of Escherichia-Shigella levels in the gut microbiome. As such, gut microbiota dysbiosis might emerge as a metabolic link in chondrocyte senescence induced by DOCA-triggered hypertension. The underlying molecular mechanism warrants further investigation.

Preliminary Findings of the High Quantity of Microplastics in Faeces of Hong Kong Residents.

Microplastics are recognised as a ubiquitous and hazardous pollutant worldwide. These small-sized particles have been detected in human faeces collected from a number of cities, providing evidence of human ingestion of microplastics and their presence in the gastrointestinal tract. Here, using Raman spectroscopy, we identified an average of 50 particles g-1 (20.4-138.9 particles g-1 wet weight) in faeces collected from a healthy cohort in Hong Kong. This quantity was about five times higher than the values reported in other places in Asia and Europe. Polystyrene was the most abundant polymer type found in the faeces, followed by polypropylene and polyethylene. These particles were primarily fragments, but about two-thirds of the detected polyethylene terephthalate were fibres. More than 88% of the microplastics were smaller than 300 µm in size. Our study provides the first data on the faecal level, and thus the extent of ingestion, of microplastics in Hong Kong's population. This timely assessment is crucial and supports the recently estimated ingestion rate of microplastics by Hong Kong residents through seafood consumption, which is one of the highest worldwide. These findings may be applicable to other coastal populations in South China with similar eating habits.

The clinical application of metagenomic next-generation sequencing for detecting pathogens in bronchoalveolar lavage fluid: case reports and literature review.

INTRODUCTION: Clinical metagenomic next-generation sequencing (mNGS) allows a comprehensive genetic analysis of microbial materials. Different from other traditional target-driven molecular diagnostic tests, such as PCR, mNGS is a hypothesis-free diagnostic approach that allows a comprehensive genetic analysis of the clinical specimens that cover nearly any common, rare, and new pathogens ranging broadly from viruses, bacteria, fungi to parasites. AREAS COVERED: In this article, we discussed the clinical application of the mNGS using two clinical cases as examples and described the use of mNGS to assist the diagnosis of parasitic pulmonary infection. The advantages and challenges in implementing mNGS in clinical microbiology are also discussed. EXPERT OPINION: mNGS is a promising technology that allows quick diagnosis of infectious diseases. Currently, a plethora of sequencing and analysis methods exists for mNGS, each with individual merits and pitfalls. While standards and best practices were proposed by various metagenomics working groups, they are yet to be widely adopted in the community. The development of a consensus set of guidelines is necessary to guide the usage of this new technology and the interpretation of NGS results before clinical adoption of mNGS testing.

Whole genome amplicon sequencing and phylogenetic analysis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from lineage B.1.36.27 isolated in Hong Kong.

BACKGROUND: The import of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage B.1.36.27 has sparked the fourth wave of COVID-19 outbreak in Hong Kong. This strain has been circulating in Hong Kong since September 2020 but rarely found in other countries (<1%). RESEARCH DESIGN AND METHODS: A total of 14 SARS-CoV-2 genome sequences collected from patients in Hong Kong between July 2020 and March 2021 were determined by whole viral genome sequencing using Illumina next-generation sequencing platform, followed by phylogenetic analysis. RESULTS: Of the 14 SARS-CoV-2 genome sequences analyzed, 9 strains belonged to the PANGO lineage B.1.36.27, GISAID clade GH, and Nextclade clade 20A. Compared to the reference genome, 31 nucleotide differences and 11 amino acid differences were identified in the genome of the SARS-CoV-2 from PANGO lineage B.1.36.27. CONCLUSIONS: We reported the nucleotides and amino acids mutations identified in the SARS-CoV-2 from PANGO lineage B.1.36.27. Our viral genome sequences enriched the understanding of SARS-CoV-2 mutational landscape and improved the repertoire of known SARS-CoV-2 variants for tracking and tracing. From this study, we found no evidence to show that SARS-CoV-2 from lineage B.1.36.27 can compromise existing vaccines and antibody therapies.

Potential Benefits of Probiotics and Prebiotics for Coronary Heart Disease and Stroke.

Among cardiovascular diseases (CVDs), a major cause of morbidity and mortality worldwide, coronary heart disease and stroke are the most well-known and extensively studied. The onset and progression of CVD is associated with multiple risk factors, among which, gut microbiota has received much attention in the past two decades. Gut microbiota, the microbial community colonizing in the gut, plays a prominent role in human health. In particular, gut dysbiosis is directly related to many acute or chronic dysfunctions of the cardiovascular system (CVS) in the host. Earlier studies have demonstrated that the pathogenesis of CVD is strongly linked to intestinal microbiota imbalance and inflammatory responses. Probiotics and prebiotics conferring various health benefits on the host are emerging as promising therapeutic interventions for many diseases. These two types of food supplements have the potential to alleviate the risks of CVD through improving the levels of several cardiovascular markers, such as total and low-density lipoprotein (LDL) cholesterol, high sensitivity C-reactive protein (hs-CRP), and certain cytokines involved in the inflammatory response. In this review, we focus mainly on the preventive effects of probiotics and prebiotics on CVD via rebalancing the structural and functional changes in gut microbiota and maintaining immune homeostasis.