Rational Development of a Polysaccharide-Protein-Conjugated Nanoparticle Vaccine Against SARS-CoV-2 Variants and Streptococcus pneumoniae

The ongoing COVID-19 pandemic caused by SARS-CoV-2 has led to millions of deaths worldwide. Streptococcus pneumoniae (S. pneumoniae) remains a major cause of mortality in underdeveloped countries. A vaccine that prevents both SARS-CoV-2 and S. pneumoniae infection represents a long-sought "magic bullet". Herein, a nanoparticle vaccine, termed SCTV01B, is rationally developed by using the capsular polysaccharide of S. pneumoniae serotype 14 (PPS14) as the backbone to conjugate with the recombinant receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. The final formulation of conjugated nanoparticles in the network structure exhibits high thermal stability. Immunization with SCTV01B induces potent humoral and Type 1/Type 2 T helper cell (Th1/Th2) cellular immune responses in mice, rats, and rhesus macaques. In particular, SCTV01B-immunized serum not only broadly cross-neutralizes all SARS-CoV-2 variants of concern (VOCs), including the most recent Omicron variant, but also shows high opsonophagocytic activity (OPA) against S. pneumoniae serotype 14. Finally, SCTV01B vaccination confers protection against challenges with the SARS-CoV-2 mouse-adapted strain and the original strain in established murine models. Collectively, these promising preclinical results support further clinical evaluation of SCTV01B, highlighting the potency of polysaccharide-RBD-conjugated nanoparticle vaccine platforms for the development of vaccines for COVID-19 and other infectious diseases.

Menopausal hormone therapy: what are the problems in the perception of Chinese physicians?

OBJECTIVE

This study aimed to investigate Chinese physicians' perception and attitudes toward menopausal hormone therapy (MHT).

METHODS

This nationwide online survey was conducted in China. Physicians registered in the WeChat groups of the Gynecological Endocrinology Committee of China's Maternal and Child Health Care Association received a message invitation to complete this anonymous online survey from April 2020 to July 2020. Physicians' knowledge of and attitudes toward MHT were surveyed.

RESULTS

In total, 4672 questionnaires were submitted; only completed questionnaires could be submitted. The message was sent to 6021 doctors, so the response rate was 77.6%. Overall, 77.9-92.9% of physicians knew the common indications and contraindications to MHT. Additionally, 90.6%, 85.4%, 80.7% and 37.5% of physicians thought that MHT would increase the risk of venous thrombosis, breast cancer, endometrial cancer and weight gain, respectively. In total, 58.1% of the physicians mistakenly believed that a sex hormone test was one of the necessary examinations to reassess MHT prescription during follow-up visits. We found that 68.5% of physicians would consider using MHT themselves or recommend MHT to their partners in the future, and 11.4% were currently using MHT.

CONCLUSIONS

Most Chinese physicians have basic knowledge of MHT. Their misunderstandings about MHT mainly centered on the risks of endometrial cancer, weight gain and the necessary examinations during follow-up visits. These misunderstandings need to be clarified in future professional training programs.

[Progress in the practice of surveillance and early warning of infectious diseases in major countries and regions]

The COVID-19 pandemic is yet another reminder that the threat of infectious disease has never really gone away. As the cornerstone of preventing and controlling infectious diseases, effective surveillance and early warning are of great significance in understanding the outbreak and epidemic of specific infectious diseases and putting forward effective prevention and control measures. Therefore, we must continue strengthening the construction of infectious disease surveillance and early warning system. We reviewed the surveillance and early warning practices of infectious diseases in major countries and regions, then discussed the development direction in the field of surveillance and early warning of infectious diseases to provide the reference for strengthening the construction and capacity of infectious disease surveillance and early warning system in China.

Memory B cell repertoire from triple vaccinees against diverse SARS-CoV-2 variants

Omicron (B.1.1.529), the most heavily mutated SARS-CoV-2 variant so far, is highly resistant to neutralizing antibodies, raising concerns about the effectiveness of antibody therapies and vaccines1,2. Here we examined whether sera from individuals who received two or three doses of inactivated SARS-CoV-2 vaccine could neutralize authentic Omicron. The seroconversion rates of neutralizing antibodies were 3.3% (2 out of 60) and 95% (57 out of 60) for individuals who had received 2 and 3 doses of vaccine, respectively. For recipients of three vaccine doses, the geometric mean neutralization antibody titre for Omicron was 16.5-fold lower than for the ancestral virus (254). We isolated 323 human monoclonal antibodies derived from memory B cells in triple vaccinees, half of which recognized the receptor-binding domain, and showed that a subset (24 out of 163) potently neutralized all SARS-CoV-2 variants of concern, including Omicron. Therapeutic treatments with representative broadly neutralizing monoclonal antibodies were highly protective against infection of mice with SARS-CoV-2 Beta (B.1.351) and Omicron. Atomic structures of the Omicron spike protein in complex with three classes of antibodies that were active against all five variants of concern defined the binding and neutralizing determinants and revealed a key antibody escape site, G446S, that confers greater resistance to a class of antibodies that bind on the right shoulder of the receptor-binding domain by altering local conformation at the binding interface. Our results rationalize the use of three-dose immunization regimens and suggest that the fundamental epitopes revealed by these broadly ultrapotent antibodies are rational targets for a universal sarbecovirus vaccine.

[Evaluation of efficiency of different anti-cysticercus antibody test kits for serodiagnosis of cysticercosis]

OBJECTIVE

To evaluate the diagnostic efficiency of four anti-cysticercus IgG, IgG4 or IgM antibody test kits (enzyme-linked immunosorbent assay, ELISA) by different manufacturers, so as to provide insights into the epidemiological investigation and clinical detection of cysticercosis.

METHODS

Forty serum samples from cerebral cysticercosis patients, 100 serum samples from healthy volunteers, 30 serum samples from paragonimiasis skrjabini patients, 17 serum samples from cystic echinococcosis and 19 serum samples from subcutaneous or cerebral sparganosis patients were collected and detected using anti-cysticercus IgG, IgG4 or IgM antibody test kits (brand A) and the anti-cysticercus IgG antibody test kit (brand B). The sensitivity, specificity and false negative rate of the four kits for detection of cysticercosis were estimated.

RESULTS

The anti-cysticercus IgG, IgG4 or IgM antibody test kits (brand A) showed 95.00% (38/40), 87.50% (35/40), 7.50% (3/40) sensitivities and 98.00% (98/100), 100.00% (100/100) and 100.00% (100/100) for detection of cysticercosis, while the anti-cysticercus IgG antibody test kit (brand B) presented a 75.00% (30/40) sensitivity and 100.00% (100/100) specificity for detection of cysticercosis. The sensitivity for detection of cysticercosis was significantly higher by the anti-cysticercus IgG antibody test kit (brand A) than by the anti-cysticercus IgG antibody test kit (brand B) (χ² = 6.28, P < 0.05); however, no significant difference was seen in the specificity by two kits (χ² = 2.01, P > 0.05). The four ELISA kits showed overall false positive rates of 37.88% (25/66), 22.73% (15/66), 62.12% (41/66) and 15.15% (10/66) for detection of paragonimiasis, echinococcosis and sparganosis (χ² = 37.61, P < 0.05), and the anti-cysticercus IgG antibody test kit (brand A) presented the highest overall false positive rate for detection of paragonimiasis, echinococcosis and sparganosis (χ² = 7.56, P' < 0.008), while a higher overall false positive rate was seen for detection of paragonimiasis, echinococcosis and sparganosis by the anti-cysticercus IgG antibody test kit (brand A) than by the anti-cysticercus IgG antibody test kit (brand B) (χ² = 8.75, P' < 0.008). The four ELISA kits showed false positive rates of 40.00% (12/30), 16.67% (5/30), 76.67% (23/30) and 13.33% (4/30) for detection of paragonimiasis (χ2 = 32.88, P < 0.05) and 21.05% (4/19), 26.32% (5/19), 73.68% (14/19) and 15.79% (3/19) for detection of sparganosis (χ² = 19.97, P < 0.05), and the highest false positive rates were found by the anti-cysticercus IgM antibody test kit (brand A) for detection of paragonimiasis and sparganosis (all P' < 0.008). However, the four ELISA kits showed comparable false positive rates of 52.94% (9/17), 29.41% (5/17), 23.53% (4/17) and 17.65% (3/17) for detection of echinococcosis (χ² = 8.24, P > 0.05). In addition, the anti-cysticercus IgM anti-body test kit (brand A) showed false positive rates of 76.67% (23/30), 23.53% (4/17) and 73.68% (14/19) for detection of paragonimiasis, echinococcosis and sparganosis (χ² = 14.537, P < 0.05), with the lowest false positive rate seen for detection of echinococcosis (χ² = 14.537, P' < 0.014), while no significant differences were seen in the false positive rate for detection of paragonimiasis, echinococcosis and sparganosis by other three ELISA kits (all P > 0.05).

CONCLUSIONS

The four anti-cysticercus IgG, IgG4 or IgM antibody test kits exhibit various efficiencies for serodiagnosis of cysticercosis. The anti-cysticercus IgG antibody test kit (brand A) has a high sensitivity for serodiagnosis of cysticercosis; however, it still needs to solve the problems of cross-reaction with other parasitic diseases and stability.

[Analysis of lactate dehydrogenase gene polymorphisms and prediction of B cell epitopes in four human Plasmodium species]

OBJECTIVE

To analyze the polymorphism of Plasmodium lactate dehydrogenase (pLDH) gene and predict B-cell epitopes in pLDH peptides in four species of human malaria parasites.

METHODS

The blood samples and epidemiological characteristics were collected from malaria cases in Yunnan Province registered in the National Notifiable Disease Report System. The pLDH genes of four human Plasmodium species were amplified using nested PCR assay and sequenced. The polymorphisms of pLDH genes was analyzed using the software MEGA version 7.0.26 and DnaSP version 5.10, and the B-cell epitopes were predicted in pLDH peptides using the Immune Epitope Database (IEDB).

RESULTS

The sequences of P. vivax LDH (PvLDH), P. falciparum LDH (PfLDH), P. ovale LDH (PoLDH) and P. malariae LDH (PmLDH) genes were obtained from 153, 29, 17 and 11 blood samples from patients with P. vivax, P. falciparum, P. ovale and P. malariae malaria, respectively, which included 15, 2, 4 and 2 haplotypes and had a nucleotide diversity (π) of 0.104. A high level of intra-species differentiation was seen in the PoLDH gene (π = 0.012), and the π values were all < 0.001 for PvLDH, PfLDH and PmLDH genes. Active regions of B-cell antigen were predicted in the pLDH peptide chain of four human malaria parasites, of 4 to 5 in each chain, and the activity score was approximately 0.430. Among these peptide chains, the "86-PGKSDKEWNRD-96" short-peptide was a B-cell epitope shared by all four species of human malaria parasites, and the "266-GQYGHS (T)-271" short-peptide was present in PvLDH and PoLDH peptide chains, while "212-EEVEGIFDR-220" was only found in the PvLDH peptide chain, and "208-LISDAE-213" was only seen in the PfLDH peptide chain.

CONCLUSIONS

The PoLDH gene polymorphism may be derived from the weak negative purification selection, while PvLDH, PfLDH and PmLDH genes may maintain a relatively conservative state. There may be two B-cell epitopes "212-EEVEGIFDR-220" and "208-LISDAE-213" in the proximal region of the C terminal in the pLDH peptide chain, which is feasible to differentiate between P. vivax and P. falciparum infections.

Resveratrol protects renal damages induced by periodontitis via preventing mitochondrial dysfunction in rats

OBJECTIVES

Periodontitis is closely associated with kidney disease and reactive oxygen species (ROS) involvement. Mitochondria are the primary source of both endogenous ROS and renal energy. We investigated whether resveratrol (RSV) prevents renal injury and mitochondrial dysfunction in periodontitis rats.

METHODS

Thirty male Wistar rats were divided into control, experimental periodontitis (Ep), and Ep-RSV groups. To induce periodontitis, a steel ligature was placed on the cervix of the bilateral first maxillary molars. RSV (50 mg/kg/d) to the Ep-RSV group and vehicle to the Ep and control groups were gavaged. After 8 weeks, alveolar bone loss, pocket depth, gingival blood index, and tooth mobility were assessed. Oxidative stress parameters, mitochondrial structure, mitochondrial membrane potential (MMP), mitochondrial ROS, adenosine triphosphate (ATP), sirtuin 1 (SIRT1), and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) were analysed in renal. Renal function and histology were also evaluated.

RESULTS

Compared with the control group, the Ep group showed renal structural destruction, elevated oxidative stress levels, mitochondrial structure destruction, MMP loss, mitochondrial ROS accumulation, ATP reduction, and decreased SIRT1 and PGC-1α levels. RSV prevented these destruction (p < .05). However, there was no significant impairment in renal function (p > .05).

CONCLUSIONS

Periodontitis induced mitochondrial dysfunction in renal tissues. Resveratrol exerts a preventive effect on periodontitis-induced kidney injury by preventing mitochondrial dysfunction.

[Immunogenicity and safety of a booster vaccination with an inactivated severe acute respiratory syndrome coronavirus 2 vaccine in adults aged 18 to 59 years]

Objective: To assess the immunogenicity and safety of a booster vaccination with an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. Methods: The phase Ⅱ trial of an inactivated SARS-CoV-2 vaccine was conducted by Jiangsu Provincial Center for Disease Control and Prevention (CDC) since October 2020. The subjects were healthy adults aged 18-59 years, excluding pregnant, and not breastfeeding women. The primary vaccination schedule groups were 0-14 d 5 μg, 0-14 d 10 μg, 0-28 d 5 μg and 0-28 d 10 μg, respectively. And 50 participants in each group, a total of 200, who have received 2-doses primary vaccination were selected in ascending order of the study number and vaccinated with a booster dose (same dosage as primary vaccination) at the 6th months after post the primary vaccination (30-day window period). Blood samples were collected before and after boosting and tested for the geometric mean titers (GMT) and seroconversion of live virus neutralizing antibody, pseudovirus neutralizing antibody and receptor-binding-domain (RBD) IgG antibody. Adverse events (AE) were collected and assessed within 28 days after boosting. Results: The ages of subjects in group 0-14 d 5 μg, 0-14 d 10 μg, 0-28 d 5 μg and 0-28 d 10 μg were (43.98±9.58), (43.46±9.34), (42.56±9.08) and (43.94±11.05) years old, respectively (P=0.877). Sex ratios were balanced among the 4 groups (P=0.331). The live virus neutralizing antibody GMT (95%CI) in group 0-14 d 5 μg, 0-14 d 10 μg, 0-28 d 5 μg and 0-28 d 10 μg increased from 4.07 (3.30-5.04), 3.75 (3.08-4.55), 8.33 (7.01-11.11) and 7.69 (6.19-9.57) before the booster vaccination to 284.84 (215.28-376.86), 233.05 (178.61-304.08), 274.81 (223.64-337.68) and 280.77 (234.59-336.04) in 28 days after the booster vaccination, respectively. The rates of live virus neutralizing antibody seroconversion were all 100% in the 4 groups. The AE incidences following booster vaccination were 18.0% (9 cases), 4.0% (2 cases), 12% (6 cases), and 12% (6 cases) in the 4 groups(P=0.182). No AE was graded as level 3 or worse. No serious AE was reported. Conclusion: One booster vaccination of an inactivated SARS-CoV-2 vaccine administered 6 months after primary vaccination showed good immunogenicity and safety.

Naphthoquine: A Potent Broad-Spectrum Anti-Coronavirus Drug In Vitro

COVID-19 has spread around the world and caused serious public health and social problems. Although several vaccines have been authorized for emergency use, new effective antiviral drugs are still needed. Some repurposed drugs including Chloroquine, Hydroxychloroquine and Remdesivir were immediately used to treat COVID-19 after the pandemic. However, the therapeutic effects of these drugs have not been fully demonstrated in clinical studies. In this paper, we found an antimalarial drug, Naphthoquine, showed good broad-spectrum anti-coronavirus activity. Naphthoquineinhibited HCoV-229E, HCoV-OC43 and SARS-CoV-2 replication in vitro, with IC₅₀ = 2.05 ± 1.44 μM, 5.83 ± 0.74 μM, and 2.01 ± 0.38 µM, respectively. Time-of-addition assay was also performed to explore at which stage Naphthoquine functions during SARS-CoV-2 replication. The results suggested that Naphthoquine may influence virus entry and post-entry replication. Considering the safety of Naphthoquine was even better than that of Chloroquine, we think Naphthoquine has the potential to be used as a broad-spectrum drug for coronavirus infection.

[Effectiveness of training on Taenia solium taeniasis and cysticercosis control knowledge among medical professionals in disease-elimination pilot areas of Henan Province]

OBJECTIVE

To investigate the changes in the awareness rate of Taenia solium taeniasis and cysticercosis control knowledge among medical professionals before and after training in Fangcheng County, a disease-elimination pilot area of Henan Province, so as to evaluate the effectiveness of the training.

METHODS

Three townships in Fangcheng County were randomly selected as the study townships, including Dushu, Bowang and Yangji townships, while Erlangmiao, Yanglou and Xiaoshidian townships in the county were randomly selected as the control townships. The grassroots medical professionals in the study townships were given once training on T. solium taeniasis and cysticercosis control knowledge each year from 2016 to 2020, while those in the control townships were given no interventions. All village-level doctors and a part of township-level public health professionals were sampled from the study and control townships as intervention and control groups. The baseline and final assessments of the awareness of T. solium taeniasis and cysticercosis control knowledge were performed using questionnaire survey in intervention and control groups in 2016 and 2020, and the awareness of T. solium taeniasis and cysticercosis control knowledge was compared between the two groups.

RESULTS

A total of 663 medical professionals were investigated in Fangcheng County from 2016 to 2020, including 474 participants in the intervention group and 189 participants in the control group. Results from the 2016 baseline survey showed that the awareness rate of T. solium taeniasis and cysticercosis control knowledge was 28.83% (47/163) among grassroots medical professionals in Fangcheng County, and there were no significant differences in the awareness between the intervention (32.47%, 25/77) and control groups (25.58%, 22/86) (χ² = 0.939, P > 0.05), between men (30.50%, 43/141) and women (18.18%, 4/22) (χ² = 1.406, P > 0.05) or between village- (31.39%, 43/137) and township-level medical professionals (15.38%, 4/26) (χ² = 2.727, P > 0.05), while significant differences were found in the awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in terms of education levels (χ² = 8.190, P < 0.05) and duration of working experiences (χ² = 12.617, P < 0.05), and the awareness rate of T. solium taeniasis and cysticercosis control knowledge increased with education levels among medical professionals (χ² = 6.768, P < 0.05). Only 5.52% (9/163) of the medical professionals had a history of diagnosis and therapy of T. solium taeniasis or cysticercosis, and only 1.23% (2/163) received training on T. solium taeniasis and cysticercosis control knowledge during the past 5 years. Results from the 2020 questionnaire survey showed a higher awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in the intervention group (93.55%, 116/124) than in the control group (46.60%, 48/103) (χ² = 61.845, P < 0.05), and no significant differences were seen in the awareness rate of T. solium taeniasis and cysticercosis control knowledge among medical professionals in terms of gender, level of medical professionals, duration of working experiences or history of diagnosis/therapy of T. solium taeniasis and cysticercosis in the intervention group (χ² = 1.089, 0.140, 0.081 and 0.453, all P values > 0.05), while there was a significant difference in the awareness rate among medical professionals with different education levels (χ² = 36.338, P < 0.05). In addition, the awareness rate of T. solium taeniasis and cysticercosis control knowledge significantly increased among medical professionals with various chracteristics in 2020 than in 2016.

CONCLUSIONS

In the low-prevalence areas of T. solium taeniasis and cysticercosis, long-term and persistent training may improve the awareness of T. solium taeniasis and cysticercosis control knowledge among grassroots medical professionals, which facilitates the timely identification of T. solium taeniasis and cysticercosis and the establishment of a sensitive disease surveillance system.

GP73 is a glucogenic hormone contributing to SARS-CoV-2-induced hyperglycemia

Severe cases of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are associated with elevated blood glucose levels and metabolic complications. However, the molecular mechanisms for how SARS-CoV-2 infection alters glycometabolic control are incompletely understood. Here, we connect the circulating protein GP73 with enhanced hepatic gluconeogenesis during SARS-CoV-2 infection. We first demonstrate that GP73 secretion is induced in multiple tissues upon fasting and that GP73 stimulates hepatic gluconeogenesis through the cAMP/PKA signaling pathway. We further show that GP73 secretion is increased in cultured cells infected with SARS-CoV-2, after overexpression of SARS-CoV-2 nucleocapsid and spike proteins and in lungs and livers of mice infected with a mouse-adapted SARS-CoV-2 strain. GP73 blockade with an antibody inhibits excessive glucogenesis stimulated by SARS-CoV-2 in vitro and lowers elevated fasting blood glucose levels in infected mice. In patients with COVID-19, plasma GP73 levels are elevated and positively correlate with blood glucose levels. Our data suggest that GP73 is a glucogenic hormone that likely contributes to SARS-CoV-2-induced abnormalities in systemic glucose metabolism.

[Effectiveness of health education interventions targeting taeniasis and cysticercosis among primary school students in disease-elimination pilot areas of Henan Province]

OBJECTIVE

To compare the changes of knowledge, attitude and practice (KAP) related to taeniasis and cysticercosis among primary school students before and after health education interventions in disease-elimination pilot areas of Henan Province, so as to evaluate the effectiveness of health education interventions.

METHODS

A primary school was selected from each of Dushu, Bowang and Yangji townships, Fangcheng County, Henan Province from 2017 to 2019; then, 2 to 3 classes were randomly selected from grade 4 to 6 in each primary school, and finally, all students in these classes were enrolled as study subjects. A thematic health education lecture pertaining to taeniasis and cysticercosis was given once each year by means of "health education in class". The KAP towards taeniasis and cysticercosis was investigated among primary school students using selffilled structured questionnaires, and the changes of awareness of taeniasis and cysticercosis control knowledge and percentage of healthy behaviors formation were compared in primary school students among years and following various frequencies of health education interventions.

RESULTS

More than 10 thousand person-time primary school students received health education interventions during the period from 2017 to 2019, and a total of 1 223 person-time primary school students were investigated during the 3-year study period, including 633 person-time men and 590 person-time women and 88.55% of primary school students at ages of 10 to 12 years. The proportion of households raising pigs and using dry toiliets decreased from 5.30% (24/453) and 18.10% (82/453) in 2017 to 3.60% (13/361) and 11.08% (40/361) in 2019, respectively. The awareness rate of taeniasis and cysticercosis control knowledge increased significantly from 0.22% (1/453) in 2017 to 62.59% (256/409) in 2018 and 76.73% (277/361) in 2019 (χ² = 567.60, P < 0.001), and the awareness rate was 85.25% (104/122) among primary school students attending the thematic special health education courses for successive three times. The awareness rates of taeniasis and cysticercosis control knowledge were 0.44% (1/225), 58.00% (116/200) and 71.63% (149/208) among male students and 0 (0/338), 66.99% (140/209) and 83.66% (128/153) among female students from 2017 to 2019, and there was a significant difference in the awareness of taeniasis and cysticercosis control knowledge between male and female students in 2019 (χ² = 7.14, P = 0.01). On-site teaching by doctors was the students' favorite way to receive health education interventions (70.07%, 857/1 223), followed by watching health education videos (58.63%, 717/1 223) and seeing parasite specimens (48.9%, 598/1 223). The proportion of students' families who used cutting boards for raw and cooked food separately increased from 7.28% (33/453) in 2017 to 47.37% (171/361) in 2019, was 67.21% (82/122) among students attending the health education courses for successive three times. The proportion of students who frequently washed their hands before meals and after using toilet increased from 71.96% (324/453) in 2017 to 89.47% (319/361) in 2019 and was 95.90% (117/122) among students attending the health education courses for successive three times. In addition, the percentage of students washing hands frequently in families using dry toilets was significantly lower in those who did not use dry toilets (χ² = 9.21, P = 0.002), and the proportion of students with a habit of eating raw or undercooked meat decreased significantly from 35.76% (162/453) in 2017 to 6.65% (24/361) in 2019 (χ² = 69.11, P < 0.01).

CONCLUSIONS

The thematic health education activity of "health education in class" contributes greatly to the increase in the awareness of taeniasis and cysticercosis control knowledge and the rate of healthy behaviors formation among primary school students in diseaseelimination pilot areas of Henan Province.

ToxR modulates biofilm formation in fish pathogen Vibrio harveyi

Vibrio harveyi is a common aquaculture pathogen causing diseases in a variety of aquatic animals. toxR, a conserved virulence-associated gene in vibrios, is identified in V. harveyi 345, a pathogenic strain isolated from diseased fish. In this study, to gain insight into function of ToxR in V. harveyi, an in-frame deletion of the toxR gene was constructed to reveal the role of ToxR in the physiology and virulence of V. harveyi. The statistical analysis showed no significant differences in the growth ability, motility, extracellular protease secretion, antibiotic susceptibility, virulence by intraperitoneal injection and the ability of V. harveyi to colonize the spleen and liver tissues of the pearl gentian grouper between the wild-type (WT) and the toxR mutant. However, the deletion of toxR increased the biofilm formation. The structure of the V. harveyi biofilm was further analysed by using scanning electron microscopy (SEM) and confocal laser scanning microscopy, and the results showed that deletion of toxR increased the number and density of V. harveyi biofilm. Since biofilm production is flagella, exopolysaccharide (EPS) and lipopolysaccharide dependent, 16 of V. harveyi biofilm-related genes were selected for further analysis. Based on quantitative real-time reverse transcription-PCR, the expression levels of these genes, including genes flrB, motY and mshA, flaE, flrA and gmhD, were significantly up-regulated in the ΔtoxR⁺ strain as compared with the WT⁺ and C-ΔtoxR strains during the early and mid-exponential, while epsG, flaA, flaE, flgD, flgE, flrB, flrC, lpxB, motY, mshA and scrG genes were inhibited because of deletion of the toxR gene in the stationary growth phase. Our results indicate that ToxR plays an important role in controlling the biofilm in V. harveyi.

[Establishment of a fluorescent recombinase-aided isothermal amplification assay for nucleic acid detection of Paraginiumus skrjabini and preliminary evaluation of its detection efficiency]

OBJECTIVE

To establish a nucleic acid assay for detection of Paragonimus skrjabini based on the recombinase-aided isothermal amplification (RAA) technique, and to preliminarily evaluate its detection efficiency.

METHODS

The metacercariae of P. skrjabini, P. westermani and Euparagonimus cenocopiosus were isolated from crabs, and genomic DNA was extracted for molecular characterization. The cytochrome coxidase 1 (cox1) gene sequence of P. skrjabini was selected as the target gene fragment, and the primers and probes were designed, screened and synthesized for RAA assay. The genomic DNA of P. skrjabini metacercariae from Jiyuan City and Yiyang County of Luoyang City, Henan Province were used as templates for verification of the fluorescent RAA assay. The fluorescent RAA assay was performed to detect different concentrations of plasmids containing target gene fragment and P. skrjabini metacercariae genomic DNA to determine the sensitivity. Fluorescent RAA assay was performed with recombinant plasmids containing P. skrjabini cox1 gene sequences at different concentrations and P. skrjabini genomic DNA as templates to evaluate its sensitivity, and the genomic DNA of P. westermani, E. cenocopiosus, Clonorchis sinensis and Schistosoma japonicum was detected with fluorescent RAA assay to evaluate its specificity.

RESULTS

P. skrjabini, P. westermani and E. cenocopiosus metacercariae were isolated from crabs, respectively. Molecular characterization and phylogenetic analysis confirmed their homology with the genes sequences of standard Paragonimus strains in GenBank. A fluorescent RAA assay was successfully established for nucleic acid detection of P. skrjabini, and the genomic DNA of P. skrjabini metacercariae from Jiyuan City and Yiyang County of Luoyang City, Henan Province was amplified using the fluorescent RAA assay within 5 min, while the negative control was not amplified. If the recombinant plasmid containing P. skrjabini cox1 gene sequences was used as templates, the fluorescent RAA assay showed the lowest detection limit of 10 copies/μL, and positive amplification was observed within 5 min. If genomic DNA was used as templates, the fluorescent RAA assay showed the lowest detection limit of 10 pg/μL, and all positive amplifications were found within 5 to 10 min. In addition, the fluorescent RAA assay was tested negative for P. westermani, E. cenocopiosus, C. sinensis and S. japonicum.

CONCLUSIONS

A rapid, sensitive and specific fluorescent RAA assay is successfully established for nucleic acid detection of P. skrjabini, which has potential values in rapid field detection and species identification in freshwater crabs in areas endemic for P. skrjabini.

Rescue of BDNF expression by the thalamic parafascicular nucleus with chronic treatment with the mGluR2/3 agonist LY379268 may contribute to the LY379268 rescue of enkephalinergic striatal projection neurons in R6/2 Huntington's disease mice

We have found that daily subcutaneous injection with a maximum tolerated dose of the mGluR2/3 agonist LY379268 (20 mg/kg) beginning at 4 weeks of age dramatically improves the motor, neuronal and neurochemical phenotype in R6/2 mice, a rapidly progressing transgenic model of Huntington's disease (HD). We also previously showed that the benefit of daily LY379268 in R6/2 mice was associated with increases in corticostriatal brain-derived neurotrophic factor (BDNF), and in particular was associated with a reduction in enkephalinergic striatal projection neuron loss. In the present study, we show that daily LY379268 also rescues expression of BDNF by neurons of the thalamic parafascicular nucleus in R6/2 mice, which projects prominently to the striatum, and this increase too is linked to the rescue of enkephalinergic striatal neurons. Thus, LY379268 may protect enkephalinergic striatal projection neurons from loss by boosting BDNF production and delivery via both the corticostriatal and thalamostriatal projection systems. These results suggest that chronic treatment with mGluR2/3 agonists may represent an approach for slowing enkephalinergic neuron loss in HD, and perhaps progression in general.

CD147 antibody specifically and effectively inhibits infection and cytokine storm of SARS-CoV-2 and its variants delta, alpha, beta, and gamma

SARS-CoV-2 mutations contribute to increased viral transmissibility and immune escape, compromising the effectiveness of existing vaccines and neutralizing antibodies. An in-depth investigation on COVID-19 pathogenesis is urgently needed to develop a strategy against SARS-CoV-2 variants. Here, we identified CD147 as a universal receptor for SARS-CoV-2 and its variants. Meanwhile, Meplazeumab, a humanized anti-CD147 antibody, could block cellular entry of SARS-CoV-2 and its variants-alpha, beta, gamma, and delta, with inhibition rates of 68.7, 75.7, 52.1, 52.1, and 62.3% at 60 μg/ml, respectively. Furthermore, humanized CD147 transgenic mice were susceptible to SARS-CoV-2 and its two variants, alpha and beta. When infected, these mice developed exudative alveolar pneumonia, featured by immune responses involving alveoli-infiltrated macrophages, neutrophils, and lymphocytes and activation of IL-17 signaling pathway. Mechanistically, we proposed that severe COVID-19-related cytokine storm is induced by a "spike protein-CD147-CyPA signaling axis": Infection of SARS-CoV-2 through CD147 initiated the JAK-STAT pathway, which further induced expression of cyclophilin A (CyPA); CyPA reciprocally bound to CD147 and triggered MAPK pathway. Consequently, the MAPK pathway regulated the expression of cytokines and chemokines, which promoted the development of cytokine storm. Importantly, Meplazumab could effectively inhibit viral entry and inflammation caused by SARS-CoV-2 and its variants. Therefore, our findings provided a new perspective for severe COVID-19-related pathogenesis. Furthermore, the validated universal receptor for SARS-CoV-2 and its variants can be targeted for COVID-19 treatment.

[Prevalence and influencing factors of Enterobius vermicularis infections among children in Fanxian County of Henan Province in 2019]

OBJECTIVE

To investigate the prevalence and influencing factors of Enterobius vermicularis infections among children in Fanxian County, Henan Province in 2019, so as to provide insights into the management of enterobiasis.

METHODS

Five kindergartens were selected in urban and rural areas of Fanxian County, Henan Province using the stratified sampling method in 2019, and a census of E. vermicularis infections was performed among all children in the kindergartens. E. vermicularis eggs were detected using adhesive and scotch cellophane-tape anal swab methods, and the basic characteristics of children and their families, health habits and the kindergartens' information were investigated with questionnaires. Logistic regression analysis was used to investigate the risk factors and protective factors of pinworm infection in children.

RESULTS

A total of 671 children were tested, and the mean prevalence of E. vermicularis infections was 15.50% (104/671). The prevalence of E. vermicularis infections was higher among children in rural kindergartens (28.13%, 72/256) than in urban kindergartens (7.71%, 32/415) (χ² = 50.380, P < 0.01), and greater in private kindergartens (32.26%, 60/186) than in public kindergartens (9.07%, 44/485) (χ² = 55.183, P < 0.01). There was no gender-specific prevalence of E. vermicularis infections among children (χ² = 1.442, P > 0.05), and the prevalence of E. vermicularis infections presented a tendency towards a rise with age (χ²_trend = 8.373, P < 0.05) and school grade (χ²_trend = 30.274, P < 0.05). Logistic regression analysis identified rural kindergartens and high grades as risk factors, and separate washing of children's and adults' cloths, frequent bathing and frequent dinnerware disinfection in kindergartens as protective factors for E. vermicularis infections among children. In addition, there was no significant difference in the detection of E. vermicularis infections among children by using adhesive (73.08%, 76/104) and scotch cellophane-tape anal swab methods (56.73%, 59/104) (χ² = 3.959, P > 0.05).

CONCLUSIONS

The prevalence of E. vermicularis infection is high among children in Fanxian Country, Henan Province. Health education and surveillance of enterobiasis are required to be intensified among children in rural kindergartens and senior grades and their parents and teachers.

[Efficacy of vaginal administration of Crinone versus Utrogestan combined with oral dydrogesterone tablets for luteal support in PGT freeze-thaw embryo transfer cycles]

OBJECTIVE

To compare the efficacy of two vaginal progesterone formulations, Crinone gel or Utrogestan capsules, combined with dydrogesterone tablets, for luteal phase support in pre-implantation genetic testing (PGT) freeze-thaw embryo transfer (FET) cycles.

METHODS

We analyzed 209 FET cycles in patients undergoing PGT-blastocyst transfer in our center between June, 2017 and June, 2020. The patients received vaginal administration of either Crinone gel (n=135) or Utrogestan capsules (n=74) combined with oral dydrogesterone tablets for luteal supplementation, and the clinical pregnancy rate (CPR) and miscarriage rate (MR) were compared between the two groups.

RESULTS

The Crinone gel and Utrogestan capsule groups were comparable for age, duration of infertility, AMH, AFC, BMI, basal FSH, LH, and E2 (P > 0.05). The gonadotrophin dose, duration of stimulation, levels of LH, E2, P and endometrial thickness on hCG day, and the numbers of oocytes retrieved, MII oocytes, 2PN and blastocysts did not differ significantly between two groups (P > 0.05). In FET cycles, no significant differences were observed between the two groups in the duration of endometrial preparation, P and endometrial thickness on endometrial transformation day, biochemical pregnancy rate (69.63% vs 78.38%), CPR (62.96% vs 72.97%), MR (12.94% vs 11.11%), vaginal bleeding rate in early pregnancy (20% vs 27.78%), or MR in patients with vaginal bleeding in early pregnancy (35.29% vs 20%) (P > 0.05).

CONCLUSION

Crinone gel and Utrogestan capsules combined with oral dydrogesterone have similar clinical efficacy for luteal support in PGT FET cycles.

[Prevalence of intestinal protozoan infections among rural children in Henan Province from 2014 to 2015]

OBJECTIVE

To investigate the prevalence and influencing factors of intestinal protozoan infections among rural children in Henan Province.

METHODS

A total of 104 survey sites were sampled from 35 counties (cities) in Henan Province using the stratified cluster sampling method to investigate the prevalence of intestinal protozoan infections among rural children from 2014 to 2015. The trophozoites and cysts of intestinal protozoa were identified using the iodine staining method and the physiological saline direct smear method (one detection for one stool sample). The prevalence of intestinal protozoan infections was compared among rural children with different characteristics, and the factors affecting intestinal protozoan infections among rural children were identified.

RESULTS

The overall prevalence of intestinal protozoan infections was 0.60% (40/6 771) among rural children in Henan Province from 2014 to 2015. There were 7 species of intestinal protozoa identified, and there was no species-specific prevalence (χ² = 37.732, P = 0.000). No significant differences were found in prevalence of intestinal protozoan infections among rural children in terms of gender (χ² = 1.793, P = 0.181), age (χ² = 1.443, P = 0.486), occupation (χ² = 0.219, P = 0.896) or ecological region (χ² = 1.700, P = 0.637). In addition, terrain (χ² = 2.311, P = 0.510), economic level (χ² = 4.322, P = 0.229), source of drinking water (χ² = 0.731, P = 0.393), eating raw vegetables (χ² = 1.134, P = 0.287) and deworming (χ² = 1.089, P = 0.297) had no remarkable effects on the prevalence of intestinal protozoan infections among rural children in Henan Province; however, the prevalence of intestinal protozoan infections varied significantly among rural children living in regions with different coverage of non-harmless toilets (χ² = 10.050, P = 0.018).

CONCLUSIONS

The prevalence of intestinal protozoan infections is low among rural children in Henan Province.