Application of two-sample Mendelian randomization method to assess the causal relationship between rheumatoid arthritis and osteoporotic fracture.

Background: The association between rheumatoid arthritis (RA) and osteoporotic fracture has garnered considerable attention; however, the causal relationships between diseases remain uncertain. Therefore, this study employed Mendelian randomization (MR) analysis to investigate the causal effects of RA on osteoporotic fracture. Methods: The summary data for RA and osteoporotic fracture were extracted from the genome-wide association studies (GWAS) catalog and the Finn Biobank database. The database provides information about diseased and health control subjects. We searched the database for the following conditions: RA, osteoporosis (OP), and osteoporotic fractures. Entries were published by investigating centers, which had established definitions and diagnostic criteria. We downloaded and processed the data to obtain the single-nucleotide polymorphisms (SNPs) strongly associated with RA, OP, and osteoporotic fracture. RA genetic associations were obtained from the GWAS catalog, including 1961 cases and 454,387 controls. The osteoporosis of the GWAS catalog involved 991 cases and 455,357 controls, and the data of the Finn Biobank involved 8,017 cases and 391,037 controls. Genetic associations for osteoporotic fracture were taken from the Finn Biobank of 1822 cases and 311,210 controls. Independent SNPs that are significantly associated with meeting the criteria of p < 5 × 10-8, r2 < 0.001, and kb = 10,000 were selected for MR analysis. The inverse variance-weighted (IVW) method along with other MR methods was employed for analysis, while sensitivity analyses were conducted to assess reliability and stability. Results: The results provided strong evidence that RA was causally and positively associated with osteoporosis from the GWAS catalog (OR = 1.16590; 95% CI: 1.04067-1.30619; p = 0.00811) and the Finn Biobank database (OR = 1.07314; 95% CI: 1.03455-1.11317; p = 0.00016). Moreover, a positive causal relationship was detected between RA and osteoporotic fracture (OR = 1.10132; 95% CI: 1.00506-1.20680; p = 0.03863). The results were robust according to sensitivity tests. Conclusion: This study showed positive causal relationships between RA and osteoporotic fracture. These results should be considered in further studies and public health measures on osteoporosis prevention strategies.

Properties of Pacific white shrimp (Litopenaeus vannamei) collagen and its degradation by endogenous proteinases during cold storage.

Many factors are responsible for the diminished quality of shrimp during cold storage, while the role of collagen has rarely been studied. This study therefore investigated the relationship between collagen degradation and changes of textural properties of Pacific white shrimp, and its hydrolysis by endogenous proteinases. The textural properties of shrimp decreased gradually along with disruption of shrimp muscle tissues, and the chewiness property of shrimp muscle showed a linear relationship with collagen contents in muscle during 6-day-storage at 4 °C. Pepsin-solubilized collagen in shrimp muscle consisted of one α1 chain and two α2 chains, revealing a typical tripeptide sequence (i.e., Gly-X-Y) in their molecules. In addition, collagen could be hydrolyzed by crude endogenous proteinases extracted from shrimp hepatopancreas, and serine proteinase plays a critical role in the process. These findings strongly suggested that the quality reduction of shrimp during cold storage is closely associated with collagen degradation.

Research Progresses and Applications of Fluorescent Protein Antibodies: A Review Focusing on Nanobodies.

Since the discovery of fluorescent proteins (FPs), their rich fluorescence spectra and photochemical properties have promoted widespread biological research applications. FPs can be classified into green fluorescent protein (GFP) and its derivates, red fluorescent protein (RFP) and its derivates, and near-infrared FPs. With the continuous development of FPs, antibodies targeting FPs have emerged. The antibody, a class of immunoglobulin, is the main component of humoral immunity that explicitly recognizes and binds antigens. Monoclonal antibody, originating from a single B cell, has been widely applied in immunoassay, in vitro diagnostics, and drug development. The nanobody is a new type of antibody entirely composed of the variable domain of a heavy-chain antibody. Compared with conventional antibodies, these small and stable nanobodies can be expressed and functional in living cells. In addition, they can easily access grooves, seams, or hidden antigenic epitopes on the surface of the target. This review provides an overview of various FPs, the research progress of their antibodies, particularly nanobodies, and advanced applications of nanobodies targeting FPs. This review will be helpful for further research on nanobodies targeting FPs, making FPs more valuable in biological research.

Involvement of MMP-9 in collagen degradation of sea bass (Lateolabrax japonicus): Cloning, expression, and characterization.

Disintegration of intramuscular connective tissue is responsible for postmortem tenderization of fish muscles during chilled storage. Matrix metalloproteinase-9 (MMP-9) was reported to be involved in this process, whereas the mechanism has not been revealed. In the present study, purified type I and V collagens from the connective tissues of sea bass (Lateolabrax japonicus) muscles were first prepared. These two kinds of collagens comprise three polypeptide chains (α), forming a typical triple-helical domain as determined by circular dichroism. The complete coding region of MMP-9 containing an open reading frame of 2070 bp encoding 689 amino acid residues was then cloned. The recombinant MMP-9 catalytic domain (rcMMP-9) was expressed in Escherichia coli and exhibited high hydrolyzing activity toward gelatin. Besides, rcMMP-9 was effective in degrading type V collagen rather than type I collagen at 4°C. The enzymatic activity of rcMMP-9 was highly pH-dependent, and its enzymatic activity under neutral and basic conditions was higher than that under acidic conditions. Metal ion Ca2+ was necessary for the maintenance of rcMMP-9 activity, whereas Zn2+ inhibited its activity. Our present study indicated that MMP-9 is responsible for the disintegration of intramuscular connective tissues by cleaving type V collagen during postmortem tenderization of fish muscle. PRACTICAL APPLICATION: Elucidation the involvement of MMP-9 in collagen degradation will deliver a reference for the prevention of muscular protein decomposition during chilled storage of fish fillets.

The cases of twins with sialidosis type 1 / 中华神经科杂志

Sialidosis is a rare lysosomal storage disease caused by NEU1 gene mutation at 6p21.33. It is characterized by myoclonic, ataxia, epilepsy, and decreased vision. A pair of twins with sialidosis type 1 are reported to enrich clinicians ′ understanding of the disease, so as to improve the diagnosis and treatment. The proband was a 16-year-old male. The main symptom was intermittent limb involuntary trembling for 2 years, with paroxysmal loss of consciousness. Fundus examination showed cherry-red spots. His twin brother had similar symptoms, but the overall performance was mild. Whole exome sequencing results showed that both patients carried compound heterozygous mutations of c.239C>T (p.P80L) and c.803A>G (p.Y268C) in NEU1 gene, which were from their normal phenotype mother and father.

Serosurvey for SARS-CoV-2 among blood donors in Wuhan, China from September to December 2019

The emerging of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused COVID-19 pandemic. The first case of COVID-19 was reported at early December in 2019 in Wuhan City, China. To examine specific antibodies against SARS-CoV-2 in biological samples before December 2019 would give clues when the epidemic of SARS-CoV-2 might start to circulate in populations. We obtained all 88,517 plasmas from 76,844 blood donors in Wuhan between 1 September and 31 December 2019. We first evaluated the pan-immunoglobin (pan-Ig) against SARS-CoV-2 in 43,850 samples from 32,484 blood donors with suitable sample quality and enough volume. Two hundred and sixty-four samples from 213 donors were pan-Ig reactive, then further tested IgG and IgM, and validated by neutralizing antibodies against SARS-CoV-2. Two hundred and thirteen samples (from 175 donors) were only pan-Ig reactive, 8 (from 4 donors) were pan-Ig and IgG reactive, and 43 (from 34 donors) were pan-Ig and IgM reactive. Microneutralization assay showed all negative results. In addition, 213 screened reactive donors were analyzed and did not show obviously temporal or regional tendency, but the distribution of age showed a difference compared with all tested donors. Then we reviewed SARS-CoV-2 antibody results from these donors who donated several times from September 2019 to June 2020, partly tested in a previous published study, no one was found a significant increase in S/CO of antibodies against SARS-CoV-2. Our findings showed no SARS-CoV-2-specific antibodies existing among blood donors in Wuhan, China before 2020, indicating no evidence of transmission of COVID-19 before December 2019 in Wuhan, China.

Relationships of Matrix Metalloproteinase 1 and a Tissue Inhibitor of Metalloproteinase to Collagen Metabolism in Haliotis discus hannai.

In response to physical, chemical, and/or biological stimuli, considerable tissue self-degradation occurs in abalone, causing severe post-harvest quality loss. During this process, the extracellular matrix (ECM) is greatly degraded by endogenous proteases. The main component of the ECM is collagen, primarily type I collagen. Although the activity of matrix metalloproteinases (MMPs), which can specifically degrade collagen, is precisely regulated by tissue inhibitors of MPs (TIMPs), indicating that MMPs and TIMPs play crucial roles in the regulation of tissue self-degradation, few studies have reported the interaction between MMPs and TIMPs. In this study, we reveal collagenases to participate in postmortem tissue self-degradation of Haliotis discus hannai by degrading type I collagen. The recombinant MMP-1 catalytic domain (rMMP1c) of abalone with high purity and enzyme activity is expressed using a prokaryotic expression system. The optimum temperature and pH for rMMP1c are 37 °C and 7.0, respectively. The thermal denaturation temperature of rMMP1c is 67.0 ± 0.9 °C. Ethylenediamine tetraacetic acid (EDTA) and 1,10-phenanthroline can completely inhibit rMMP1c activity, while Ba2+, Ca2+, and Mg2+ can significantly elevate it. TIMP is also expressed using HEK 293F cells. Recombinant TIMP (rTIMP) shows good inhibitory activity toward rMMP1c. Inhibition kinetics analyses reveal rTIMP to be a competitive inhibitor of rMMP1c. Biolayer interferometry reveals that rTIMP can effectively bind with rMMP1c, with an equilibrium dissociation constant value of 263 nM. rMMP1c effectively degrades type I collagen γ-ß-α chains in turn, and rTIMP can significantly inhibit rMMP1c degradation activity. These results provide a theoretical basis for the study of MMP and TIMP interaction and elucidate the possible mechanism for abalone tissue self-degradation.

The Evaluation Indexes Suitable for Nonhuman Primates can be Extracted from Clinical Consciousness Disorder Assessment Scales: A Hypothesis.

BACKGROUND: Currently, case studies or clinical trials in different patient populations remain the main resource underlying the understanding of disorder of consciousness (DoC). This provides a low efficacy for the derivation of data and the implementation of associated controlled experimental designs. Preclinical models provide precise controls, reduced variability, rich data output and limited ethical complexity. Nonhuman primates are suitable model animals for disorders of consciousness due to their brain structure being very similar to that of humans. Behavioral tests remain the primary standard for assessing the consciousness status of humans. However, there is currently no behavioral assessment scale available for evaluation of the state of consciousness disorder in nonhuman primates. This presents a significant challenge for the establishment of different models of consciousness disorder. Therefore, there is considerable motivation to focus on the development of a proper tool for assessment of the state of consciousness associated with nonhuman primate models that are based on clinically common consciousness assessment scales. METHODS: It is assumed that the Delphi and level analysis methods based on clinical consciousness disorder assessment scales may provide an effective way to select and include assessment indexes for levels of consciousness in nonhuman primates. RESULTS: 8 first-level indicators with 41 second-level indexes were selected preliminary as a pool of evaluation entries of state of consciousness of nonhuman primates. CONCLUSIONS: It may be practicable to extract appropriate indicators for non-human primates from the clinical consciousness disorder assessment scales. Besides, a combination of Delphi method, behavioral analysis, electroencephalography, neuroimaging (such as positron emission tomography-computed tomography) and functional magnetic resonance imaging is necessary to test the reliability and validity of the novel scale reported here.

Ruyi Zhenbao Pills for Patients with Motor and Sensory Dysfunction after Stroke: A Double-Blinded, Randomized Placebo-Controlled Clinical Trial.

OBJECTIVE: To evaluate the efficacy and safety of Tibetan medicine Ruyi Zhenbao Pills (RZPs) in the treatment of patients with motor and sensory dysfunction after stroke. METHODS: A total of 120 convalescent stroke patients hospitalized in the Rehabilitation Department of Guangdong Provincial Hospital of Chinese Medicine from June 2017 to December 2019 were enrolled in this trial. Patients were assigned to control (60 cases) and research (60 cases) groups by computer random assignment. All patients received internal treatment and modern rehabilitation training. On this basis, the research group was given oral RZPs for 4 weeks, while the control group was given oral placebo. The primary outcome was motor function of the affected side evaluated by simplified Fugl-Meyer Motion Assessment Scale (FMA-M). The secondary outcomes included sensory function, activity of daily living (ADL), quality of life, balance function, and pain, which were assessed by Fugl-Meyer Sensory Assessment Scale (FMA-S), Modified Barthel Index (MBI), Special Scale of the Quality of Life (SS-QOL), Berg Balance Scale (BBS), and Visual Analogue Scale (VAS), respectively. All of the assessments were performed before treatment, and 4 and 8 weeks after treatment. Vital signs, liver and kidney functions, routine blood test, blood coagulation profile, and routine urinalysis of patients were monitored. RESULTS: After 4-week treatment, the FMA-M, BBS and FMA-S scores in the research group significantly increased compared with the control group (P<0.05). At 8-week follow-up, the BBS and MBI scores in the research group were higher than the control group (P<0.05). There was no statistical difference between the 2 groups in the SS-QOL and VAS scores at 4 and 8 weeks (P>0.05). Moreover, after treatment, there was no significant difference in vital signs, liver and kidney functions, blood coagulation function, blood routine and urinalysis between the 2 groups (P>0.05). CONCLUSION: RZPs improved limb motor, balance, and sensory functions of stroke patients during recovery period with good safety. (Trial registration No. NCT04029701).

Health economics evaluation of the cost and effectiveness of gray zone setting in blood ELISA screening / 中国输血杂志

【Objective】 To analyze the cost-effectiveness of ELISA grey area strategy through establishing the health economics model. 【Methods】 The serological grey area strategy evaluation model was composed of screening strategy subdecision tree, pathogen infection subdecision tree and pathogen detection subdecision tree. The key parameters in the model were obtained from literatures and research data. The cost-effectiveness of setting ELISA grey area strategy was compared by software, and multifactor sensitivity analysis was conducted. 【Results】 After setting the ELISA grey area, extra samples(5.86 cases/100 000) with serological false negativity could be detected, including HBV samples at 4.93/100 000, HCV samples at 0.27/100 000, HIV samples at 0/100 000, syphilis samples at 0.66/100 000. To yield an additional seropositive sample out of every 100 000 blood donors, blood center will afford extra 1 million yuan about. 【Conclusion】 Through this study, a cost-effectiveness evaluation model of serological detection strategy was established. Although the ELISA grey area setting can yield a small number of seropositive samples, the cost is much higher than the current affordability.

Analysis on testing ability of blood testing laboratories in domestic blood establishments across China / 中国输血杂志

【Objective】 To analyze testing ability of blood testing laboratories in domestic blood establishments, and to comprehensively understand the resource allocation, workload and unqualified blood samples. 【Methods】 All blood testing laboratories reported the quarterly quality indicator data via their EQA system on the website of National Center for Clinical Laboratories (https: //srv.clinet.cn/qblood/report/add1.aspx). We collected related quality indicators throughout 2020, including resource indicators, number of sample detection, and number (rate) of unqualified samples. All the data were integrated by EQA system. 【Results】 1) Throughout 2020, 324 blood testing laboratories reported that 13 529 778 donations were tested by immunoassays and 13 892 927 donations were tested by nucleic acid testing(NAT). Among them, 253 laboratories reported the data correctly throughout four quarters, and they tested 12 015 407 donations. 2) The number of equipment varied greatly among different laboratories, and a certain equipment was often overloaded in some laboratories. 3) The proportion of domestic ELISA reagents was 100% (322/322), while the proportion of imported NAT reagents was 75.33% (220/300). 4) The positive rate of HBsAg was closely related to geographical locations, as Sichuan (0.86%, 5 895/689 445), Guangdong (0.57%, 5 147/895 929), and Guangxi (0.53%, 3 021/573 216) provinces demonstrated higher positive rates than that of other provincial regions. 【Conclusions】 There are many blood stations across China, with great differences in scale and equipment. There are obvious differences in the positive rates of infectious indicators in different regions. Therefore, the laboratory should make horizontal comparison with the laboratories in the same region, to improve the detection quality of the laboratory in time and effectively.

Effects of partial substitution of NaCl on myofibrillar protein properties from pearl mussel Hyriopsis cumingii muscle: Structural characteristics and aggregation behaviors.

The effects of NaCl and its partial substitutes (KCl, MgCl2 and CaCl2) on solubility, structural characteristics and aggregation behaviors of myofibrillar protein (MP) from pearl mussel muscle were investigated and compared. MP at 0.6 M NaCl was beneficial to protein unfolding and showed excellent potential functional properties. When NaCl was substituted in low level, MPs also showed good solubility and ordered microstructure as well as NaCl, especially MgCl2 and CaCl2, due to the unfolding of α-helical structures and subsequently exposed tyrosine residues and hydrophobic groups. However, the obviously increased disulfide bonds and hydrophobic interactions in high substitution level indicated the excessive non-sodium salts had negative effects on molecular rearrangement, leading to irregular and overly tight of microstructure. Thus, NaCl partially substituted by KCl, MgCl2 and CaCl2 in low substitution level is promising to improve functional properties of MP in low-sodium meat products.

Impact of sample pooling strategy on 2019-nCoV RNA detection results / 中华检验医学杂志

Objective:To evaluate the impact of sample pooling strategy on 2019-nCoV RNA detection results.Methods:Ten negative swabs were stored in 6 ml virus transport medium, mixed thoroughly and diluted 1∶2 and 1∶10. Inactivated 2019-nCoV culture medium was added to simulate pooling samples: 10 pooling samples, 5 pooling samples and 1 swab sample. Extraction and amplification were made using three nucleic acid extraction reagents a, b, and c with different extraction methods and systems, as well as five 2019-nCoV detection reagents A-E with various template loading volumes and sensitivities respectively.Results:For the same sample, the Ct values of extracted templates a were 2.10±0.47 and 3.46±0.62 earlier than extracted templates b and c. For samples with identical amplifying, the Ct valves of N and ORF1ab gene of A reagent were 1.16±0.48 and 2.36±0.54 earlier than that of reagent B. Adding nucleic acid of 10 negative swabs to the amplification system lagged the Ct values of reagent A by about 1.36±0.32 Ct, while Ct values of reagent B were not affected. Extracted by regent a, a lag of 1.66±0.39 Ct on average was observed in C, D, and E reagents in detecting pooling samples of ten swabs as compared with one swab sample. When extracting 400 copies/ml pooling samples of ten swabs by reagent a, N gene could be detected by reagents C and E, but not by reagent D.Conclusion:Large amount of extraneous DNA is introduced by sample pooling, which could interfere the effiency of extraction and amplification. Strategies of using extraction reagents with large loading volume and high effiency, together with amplification reagents with large template volume and low limit of detection are helpful for ensuring detection sensitivity of pooling samples, and greatly reducing the risk of false negative results.

Performance evaluation of two chemiluminescence immunoassay reagents for HCV antibody in blood donors screening / 中国输血杂志

【Objective】 Aim of this study was to evaluate performance of two chemiluminescence immunoassay (CLIA) reagents for hepatitis C virus antibodies (anti-HCV) detection, focusing on the feasibility of blood screening for blood donors. 【Methods】 The sero-panel samples from NCCL and the donor samples were tested with CLIA, ECLIA and two ELISA (A: double antigen sandwich method, B: indirect method) reagents synchronously to evaluate their performances respectively, and the sensitivity, specificity and CV of the four reagents were compared. 【Results】 CLIA, ECLIA, A and B reagents showed sensitivities of 99.06%(315/318), 99.69%(317/318), 99.06%(315/318) and 99.69%(317/318), and clinical specificities was 99.06%(315/318), 99.69%(317/318), 99.06%(315/318) and 99.69%(317/318), respectively. Between-run and within-run precision for ECLIA reagent ranged (both CV<8%) was better than two ELISA reagents (between-run: CV <15% and within-run: CV <20%), and the CLIA reagent also met the requirement in blood screening (CVs <14%). 【Conclusion】 This ECLIA reagent showed high sensitivity and good reproducibility together with acceptable specificity in routine sample screening, which proved its further application in blood screening. This CLIA reagent has high specificity and the same sensitivity as indirect ELISA reagent. This CLIA reagent could be used in combination with other reagents with high sensitivity to screen anti-HCV in blood donors.

Investigation and analysis of oral health status of the elderly in nursing homes in Taiyuan / 华西口腔医学杂志

OBJECTIVES@#This study aims to investigate awareness of oral health care and health status among elderly people in nursing homes in Taiyuan. Strategies for preventing and treating oral diseases and improving the quality of life of the elderly in nursing homes were formulated on the basis of analyzed data.@*METHODS@#A total of 359 participants from 48 nursing homes in six districts were selected randomly. Awareness, attitude, and behavior with regard to oral health care among the elderly were investigated through a survey using questionnaires and oral health examinations. Data were statistically analyzed with SPSS 20.0.@*RESULTS@#Among the elderly in the nursing homes in Taiyuan, awareness and behavior with regard to oral health care were deficient and inappropriate, and thus professional guidance was needed. In addition to method and time of brushing teeth and bad oral habits, the oral health status of the elderly was statistically affected by age and education. Compared with the data of the Fourth National Oral Epidemiological Investigation, the number of elderly people aged 55-64 or 65-74 years who brush their teeth every day and accept oral diagnosis and treatment was lower. However, the ratios of edentulous and missing teeth without treatment were higher than the national average level for the same age groups.@*CONCLUSIONS@#The awareness and attitude of the elderly in nursing homes with regard to oral health care are unsatisfactory, and their oral health status is poor. Education on oral health care, development of good oral care habits, and regular oral health examination are essential to the maintenance of oral health in elderly people.

The prevalence of antibodies to SARS-CoV-2 among blood donors in China

ObjectivesThe prevalence of antibodies to SARS-CoV-2 among blood donors in China remains unknown. To reveal the missing information, we investigated the seroprevalence of SARS-CoV-2 antibodies among blood donors in the cities of Wuhan, Shenzhen, and Shijiazhuang of China. DesignCross-sectional study SettingThree blood centers, located in the central, south and north China, respectively, recruiting from January to April 2020. Participants38,144 healthy blood donors donated in Wuhan, Shenzhen and Shijiazhuang were enrolled, who were all met the criteria for blood donation during the COVID-19 pandemic in China. Main outcome measuresSpecific antibodies against SARS-CoV-2 including total antibody (TAb), IgG antibody against receptor-binding domain of spike protein (IgG-RBD) and nucleoprotein (IgG-N), and IgM. Pseudotype lentivirus-based neutralization test was performed on all TAb-positive samples. In addition, anonymous personal demographic information, including gender, age, ethnicity, occupation and educational level, and blood type were collected. ResultsA total of 519 samples from 410 donors were confirmed by neutralization tests. The SARS-CoV-2 seroprevalence among blood donors was 2.29% (407/17,794, 95%CI: 2.08% to 2.52%) in Wuhan, 0.029% (2/6,810, 95%CI: 0.0081% to 0.11%) in Shenzhen, and 0.0074% (1/13,540, 95%CI: 0.0013% to 0.042%) in Shijiazhuang, respectively. The earliest emergence of SARS-CoV-2 seropositivity in blood donors was identified on January 20, 2020 in Wuhan. The weekly prevalence of SARS-CoV-2 antibodies in Wuhans blood donors changed dynamically and were 0.08% (95%CI: 0.02% to 0.28%) during January 15 to 22 (before city lockdown), 3.08% (95%CI: 2.67% to 3.55%) during January 23 to April 7 (city quarantine period) and 2.33% (95%CI: 2.06% to 2.63%) during April 8 to 30 (after lockdown easing). Female and older-age were identified to be independent risk factors for SARS-CoV-2 seropositivity among donors in Wuhan. ConclusionsThe prevalence of antibodies to SARS-CoV-2 among blood donors in China was low, even in Wuhan city. According to our data, the earliest emergence of SARS-CoV-2 in Wuhans donors should not earlier than January, 2020. As most of the population of China remained uninfected during the early wave of COVID-19 pandemic, effective public health measures are still certainly required to block viral spread before a vaccine is widely available.

REVEALING COVID-19 TRANSMISSION BY SARS-CoV-2 GENOME SEQUENCING AND AGENT BASED MODELLING

Community transmission of the new coronavirus SARS-CoV-2 is a major public health concern that remains difficult to assess. We present a genomic survey of SARS-CoV-2 from a during the first 10 weeks of COVID-19 activity in New South Wales, Australia. Transmission events were monitored prospectively during the critical period of implementation of national control measures. SARS-CoV-2 genomes were sequenced from 209 patients diagnosed with COVID-19 infection between January and March 2020. Only a quarter of cases appeared to be locally acquired and genomic-based estimates of local transmission rates were concordant with predictions from a computational agent-based model. This convergent assessment indicates that genome sequencing provides key information to inform public health action and has improved our understanding of the COVID-19 evolution from outbreak to epidemic.

How does the outbreak of 2019-nCoV spread in mainland China? A retrospective analysis of the dynamic transmission routes

The fourth outbreak of the Coronaviruses, known as the COVID-19, has occurred in Wuhan city of Hubei province in China in December 2019. We propose a time-varying sparse vector autoregressive (VAR) model to retrospectively analyze and visualize the dynamic transmission routes of this outbreak in mainland China over January 31 - February 19, 2020. Our results demonstrate that the influential inter-location routes from Hubei have become unidentifiable since February 4, 2020, whereas the self-transmission in each provincial-level administrative region (location, hereafter) was accelerating over February 4-15, 2020. From February 16, 2020, all routes became less detectable, and no influential transmissions could be identified on February 18 and 19, 2020. Such evidence supports the effectiveness of government interventions, including the travel restrictions in Hubei. Implications of our results suggest that in addition to the origin of the outbreak, virus preventions are of crucial importance in locations with the largest migrant workers percentages (e.g., Jiangxi, Henan and Anhui) to controlling the spread of COVID-19.

Tissue inhibitor of metalloproteinase-2 (TIMP-2) from red seabream (Pagrus major): Molecular cloning and biochemical characterization of highly expressed recombinant protein.

The tissue inhibitor of metalloproteinase-2 (TIMP-2) is originally characterized as an endogenous inhibitor of matrix metalloproteinases (MMPs) to response collagenolysis associated with immune challenge. In this study, the cDNA encoding TIMP-2a gene from red seabream (Pagrus major) muscle was cloned. It was 585 bp encoding a putative protein of 194 amino acids, which comprised all recognized functional domains and showed the high identity to TIMP-2as from other teleost fishes, revealing it belongs to TIMP-2a family. Soluble rTIMP-2a was efficiently expressed using a new constructed pPIC9K-rTIMP-2a vector with high inhibitory activity against to MMP-2 and MMP-9. The recombinant TIMP-2a tagged with 6 histidine residues showed the molecular mass of 23 kDa and isoelectric point of 6.50. Furthermore, the 6 disulfide bonds formed by 12 conserved cysteine residues were identified as functional motifs for its structural stability. In addition, rTIMP-2a possessed the high inhibitory activity against gelatinolytic hydrolysis and degradation of type I collagen which induced by endogenous MMPs in muscle. The results revealed the properties and inhibitory function of rTIMP-2a, which may be a pivotal role in regulation gelatinolytic MMPs metabolization during defense mechanism.

The anti-diarrhea activity of red algae-originated sulphated polysaccharides on ETEC-K88 infected mice.

Polysaccharides from red algae Porphyra haitanensis and Gracilaria lemaneiformis possess various bioactive functions, however, their anti-diarrhea activity remains incompletely defined. In the current study, sulphated polysaccharides were extracted by high pressure treatment plus ethanol precipitation from these two algae, and named PHSP(hp) and GLSP(hp), respectively. PHSP(hp) and GLSP(hp) showed decreased viscosity and molecular weight. Meanwhile, they have a certain immunomodulatory effect on wound healing and migration of RAW264.7 cells. Moreover, they significantly increased the secretion of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). A BALB/c model infected by enterotoxigenic Escherichia coli (ETEC)-K88 was also established to evaluate the anti-diarrhea activity of PHSP(hp) and GLSP(hp). The results showed that PHSP(hp) and GLSP(hp) were able to alleviate mice diarrhea symptoms. Meanwhile, they inhibited the release of pro-inflammatory cytokines and suppressed the secretion of immunoglobulin A via reducing the population of B cells. In addition, the nitroblue tetrazolium levels of mouse serum were decreased. Taken together, PHSP(hp) and GLSP(hp) alleviated the inflammatory response of ETEC-K88-induced diarrhea through both specific and non-specific immunity. Sulphated polysaccharides from red algae may be used as functional food components for remitting diarrhea.