Extremely metal-poor galaxies with metallicity below 10% of the solar value in the local universe are the best analogues to investigating the interstellar medium at a quasi-primitive environment in the early universe. In spite of the ongoing formation of stars in these galaxies, the presence of molecular gas (which is known to provide the material reservoir for star formation in galaxies such as our Milky Way) remains unclear. Here we report the detection of carbon monoxide (CO), the primary tracer of molecular gas, in a galaxy with 7% solar metallicity, with additional detections in two galaxies at higher metallicities. Such detections offer direct evidence for the existence of molecular gas in these galaxies that contain few metals. Using archived infrared data, it is shown that the molecular gas mass per CO luminosity at extremely low metallicity is approximately one-thousand times the Milky Way value.
Extremely metal-poor galaxies in the local universe are the best analogues to investigating the interstellar medium at a quasi-primitive environment in the early universe. Here, the authors detect CO emission in a galaxy at 7% solar metallicity, offering direct evidence for the presence of molecular gas.
Penicillium capsulatum is a rare Penicillium species used in paper manufacturing, but recently it has been reported to cause invasive infection. To research the pathogenicity of the clinical Penicillium strain, we sequenced the genomes and transcriptomes of the clinical and environmental strains of P. capsulatum. Comparative analyses of these two P. capsulatum strains and close related strains belonging to Eurotiales were performed. The assembled genome sizes of P. capsulatum are approximately 34.4 Mbp in length and encode 11,080 predicted genes. The different isolates of P. capsulatum are highly similar, with the exception of several unique genes, INDELs or SNPs in the genes coding for glycosyl hydrolases, amino acid transporters and circumsporozoite protein. A phylogenomic analysis was performed based on the whole genome data of 38 strains belonging to Eurotiales. By comparing the whole genome sequences and the virulence-related genes from 20 important related species, including fungal pathogens and non-human pathogens belonging to Eurotiales, we found meaningful pathogenicity characteristics between P. capsulatum and its closely related species. Our research indicated that P. capsulatum may be a neglected opportunistic pathogen. This study is beneficial for mycologists, geneticists and epidemiologists to achieve a deeper understanding of the genetic basis of the role of P. capsulatum as a newly reported fungal pathogen.
Penicillium capsulatum; novel fungal pathogen; genome sequencing; comparative genomics
The outbreak of human infections of a novel avian influenza virus A (H7N9) prompted the development of the vaccines against this virus. Like all types of influenza vaccines, H7N9 vaccine must be tested for its potency prior to being used in humans. However, the unavailability of international reference reagents for the potency determination of H7N9 vaccines substantially hinders the progress in vaccine development. To facilitate clinical development, we enlisted 5 participants in a collaborative study to develop critical reagents used in Single Radial Immunodiffusion (SRID), the currently acceptable assay for potency determination of influenza vaccine. Specifically, the hemagglutinin (HA) content of one vaccine bulk for influenza A (H7N9), herein designated as Primary Liquid Standard (PLS), was determined by SDS-PAGE. In addition, the freeze-dried antigen references derived from PLS were prepared to enhance the stability for long term storage. The final HA content of lyophilized antigen references were calibrated against PLS by SRID assay in a collaborative study. Importantly, application of these national reference standards to potency analyses greatly facilitated the development of H7N9 vaccines in China.
antigen reference standard; Hemagglutinin; Influenza virus A (H7N9); SDS-PAGE; SRID
Quality control of vaccine strains is directly associated with the safety and efficacy of inactivated whole bacterial vaccines. The assessment of genetic stability is one of the essential elements to guarantee the quality of vaccine strains. The multiple-valence inactivated leptospiral vaccine, comprising the main circulating serogroups, has played an important role in the control of Leptospira infection in China. In the present study, to assess the genetic stability of vaccine strains and develop novel quality control tests that enhance and extend the existing procedures, 7 Chinese leptospiral vaccine strains were characterized during in vivo and in vitro passages by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) analysis. The seven vaccine strains were found to have distinct sequence types (STs) and PFGE profiles. Further analysis showed that the ST and PFGE pattern of each vaccine strain, after in vivo or serial in vitro passages (up to 20 passages), were identical to those of the initial strain, demonstrating that these strains were genetically stable and homogeneous. Taken together, PFGE and MLST provide a reproducible and reliable means for confirming the identity and genetic stability of vaccine seeds, suggesting that these approaches can be used to evaluate the quality of leptospiral vaccine strains.
Genetic stability; MLST; PFGE; Quality control; leptospiral vaccine
Hepatitis A virus (HAV) remains enigmatic, despite some 1.4 million cases worldwide annually1. It differs radically from other picornaviruses, existing in an enveloped form2 and being unusually stable, both genetically and physically3, but has proved difficult to study. We report high-resolution X-ray structures for the mature virus and empty particles. The structures of the two particles are indistinguishable, apart from some disorder on the inside of the empty particle. The full virus contains the small viral protein VP4, while the empty particle harbors only the uncleaved precursor, VP0. The smooth particle surface is devoid of depressions which might correspond to receptor binding sites. Peptide scanning data extends the previously reported VP3 antigenic site4, while structure-based predictions5 suggest further epitopes. HAV contains no pocket factor, can withstand remarkably high temperature and low pH, with empty particles being even more robust than full particles. The virus probably uncoats via a novel mechanism, being built differently to other picornaviruses. It utilizes a VP2 ‘domain swap’ characteristic of insect picorna-like viruses6,7 and structure-based phylogenetic analysis places HAV between typical picornaviruses and the insect viruses. The enigmatic properties of HAV may reflect its position as a link between ‘modern’ picornaviruses and the more ‘primitive’ precursor insect viruses, for instance HAV retains the ability to move from cell-to-cell by transcytosis8,9.
Leptospirosis, caused by pathogenic Leptospira spp., has recently been recognized as an emerging infectious disease worldwide. Despite its severity and global importance, knowledge about the molecular pathogenesis and virulence evolution of Leptospira spp. remains limited. Here we sequenced and analyzed 102 isolates representing global sources. A high genomic variability were observed among different Leptospira species, which was attributed to massive gene gain and loss events allowing for adaptation to specific niche conditions and changing host environments. Horizontal gene transfer and gene duplication allowed the stepwise acquisition of virulence factors in pathogenic Leptospira evolved from a recent common ancestor. More importantly, the abundant expansion of specific virulence-related protein families, such as metalloproteases-associated paralogs, were exclusively identified in pathogenic species, reflecting the importance of these protein families in the pathogenesis of leptospirosis. Our observations also indicated that positive selection played a crucial role on this bacteria adaptation to hosts. These novel findings may lead to greater understanding of the global diversity and virulence evolution of Leptospira spp.
Two non-human glycan epitopes, galactose-α-1,3-galactose (α-gal) and Neu5Gc-α-2-6-galactose (Neu5Gc) have been shown to be antigenic when attached to Fab oligosaccharides of monoclonal antibodies (mAbs) , while α-gal attached to Fc glycans was not. However, the antigenicity of Neu5Gc on the Fc glycans remains unclear in the context that most mAbs carry only Fc glycans. After studying two clinical mAbs carrying significant amounts of Fc Neu5Gc, we show that their binding activity with anti-Neu5Gc antibody resided in a small subset of mAbs carrying two or more Fc Neu5Gc, while mAbs harboring only one Neu5Gc showed no reactivity. Since most Neu5Gc epitopes were distributed singly on the Fc of mAbs, our results suggest that the potential antigenicity of Fc Neu5Gc is low. Our study could be referenced in the process design and optimization of mAb production in murine myeloma cells and in the quality control of mAbs for industries and regulatory authorities.
Whole-cell pertussis vaccines (WPVs) have been completely replaced by the co-purified acellular vaccines (APVs) in China. To date few laboratory studies were reported for co-purified APVs in terms of their antigenic composition and protective immune responses. To further understand the antigenic composition in co-purified APVs, in the present study 2-dimensional gel electrophoresis-based proteomic technology was used to analyze the composition of co-purified APVs. The results showed that besides the main antigens pertussis toxin (PT) and filamentous hemagglutinin (FHA), co-purified APVs also contained pertactin (PRN), fimbriae (FIM) 2and3 and other minor protein antigens. Of the 9 proteins identified, 3 were differentially presented in products from manufacturer 1 and manufacturer 2. Compared with WPVs and purified APVs, co-purified APVs induced a mixed Th1/Th2 immune response with more toward to a Th1 response than the purified APVs in this study. These results hint that different immune mechanisms might be involved in protection induced by co-purified and purified APVs.
Co-purified acellular pertussis vaccines; immune responses; protection; proteomic analysis
Three inactivated EV71 whole-virus vaccines have completed Phase III clinical trials in mainland China, with high efficacy, satisfactory safety, and sustained immunogenicity. However, the molecular mechanisms how this new vaccine elicit potent immune response remain poorly understood. To characterize the primary and recall responses to EV71 vaccines, PBMC from 19 recipients before and after vaccination with EV71 vaccine are collected and their gene expression signatures after stimulation with EV71 antigen were compared. The results showed that primary and recall response to EV71 antigen have both activated an IRF7 regulating type I interferon and antiviral immune response network. However, up-regulated genes involved in T cell activation regulated by IRF1, inflammatory response, B-cell activation and humoral immune response were only observed in recall response. The specific secretion of IL-10 in primary response and IL-2,IP-10,CCL14a, CCL21 in recall response was consistent with the activation of immune response process found in genes. Furthermore, the expression of MX1 and secretion of IP-10 in recall response were strongly correlated with NTAb level at 180d after vaccination (r = 0.81 and 0.99). In summary, inflammatory response, adaptive immune response and a stronger antiviral response were indentified in recall response.
To investigate the long-term effects on immunity of an inactivated enterovirus 71 (EV71) vaccine and its protective efficacy.
A sub-cohort of 1,100 volunteers from Guangxi Province in China was eligible for enrolment and randomly administered either the EV71 vaccine or a placebo on days 0 and 28 in a phase III clinical trial and then observed for the following 2 years with approval by an independent ethics committee of Guangxi Zhuang Autonomous Region, China. Serum samples from the 350 participants who provided a full series of blood samples (at all the sampling points) within the 2-year period were collected. Vaccine-induced immune effects, including the neutralizing antibody titres and cross-protection against different genotypes of EV71, were examined. This study also evaluated the protective efficacy of this vaccine based upon clinical diagnosis.
This sub-cohort showed a >60 % drop-out rate over 2 years. The seroconversion rates among the 161 immunized subjects remained >95 % at the end of study. The geometric mean titres of neutralizing antibodies (anti-genotype C4) 360 days after vaccination in 350 subjects were 81.0 (subjects aged 6–11 months), 98.4 (12–23 months), 95.0 (24–35 months), and 81.8 (36–71 months). These titres subsequently increased to 423.1, 659.0, 545.0, and 321.9, respectively, at 540 days post-immunization (d.p.i.), and similar levels were maintained at 720 d.p.i. Higher IFN-γ/IL-4-specific responses to the C4 genotype of EV71 and cross-neutralization reactivity against major EV71 genotype strains were observed in the vaccine group compared to those in the placebo group. Five EV71-infected subjects were observed in the placebo-treated control group and none in the vaccine-immunized group in per-protocol analysis.
These results are consistent with the induction of dynamic immune responses and protective efficacy of the vaccine against most circulating EV71 strains.
Trial registration number
Clinicaltrials.gov, NCT01569581, Trial registration date: March 2012
Electronic supplementary material
The online version of this article (doi:10.1186/s12916-015-0448-7) contains supplementary material, which is available to authorized users.
Cross-neutralization; Enterovirus 71; Hand; foot; and mouth disease; Inactivated vaccine; Long-term effect
A novel avian influenza A H7N9-subtype virus emerged in China in 2013 and threatened global public health. Commercial kits that specifically detect avian influenza A (H7N9) virus RNA are urgently required to prepare for the emergence and potential pandemic of this novel influenza virus. The safety and effectiveness of three commercial molecular diagnostic assays were evaluated using a quality-control panel and clinical specimens collected from over 90 patients with confirmed avian influenza A (H7N9) virus infections. The analytical performance evaluation showed that diverse influenza H7N9 viruses can be detected with high within- and between-lot reproducibility and without cross-reactivity to other influenza viruses (H1N1 pdm09, seasonal H1N1, H3N2, H5N1 and influenza B). The detection limit of all the commercial assays was 2.83 Log10 copies/μl [0.7 Log10TCID50/mL of avian influenza A (H7N9) virus strain A/Zhejiang/DTID-ZJU01/2013], which is comparable to the method recommended by the World Health Organization (WHO). In addition, using a WHO-Chinese National Influenza Center (CNIC) method as a reference for clinical evaluation, positive agreement of more than 98% was determined for all of the commercial kits, while negative agreement of more than 99% was observed. In conclusion, our findings provide comprehensive evidence for the high performance of three commercial diagnostic assays and suggest the application of these assays as rapid and effective diagnostic tools for avian influenza A (H7N9) virus in the routine clinical practice of medical laboratories.
Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) are the primary causes of the epidemics of hand-foot-and-mouth disease (HFMD) that affect more than a million children in China each year and lead to hundreds of deaths. Although there has been progress with vaccines for EV71, the development of a CVA16 vaccine has proved more challenging, and the EV71 vaccine does not give useful cross-protection, despite the capsid proteins of the two viruses sharing about 80% sequence identity. The structural details of the expanded forms of the capsids, which possess nonnative antigenicity, are now well understood, but high resolution information for the native antigenic form of CVA16 has been missing. Here, we remedy this with high resolution X-ray structures of both mature and natural empty CVA16 particles and also of empty recombinant viruslike particles of CVA16 produced in insect cells, a potential vaccine antigen. All three structures are unexpanded native particles and antigenically identical. The recombinant particles have recruited a lipid moiety to stabilize the native antigenic state that is different from the one used in a natural virus infection. As expected, the mature CVA16 virus is similar to EV71; however, structural and immunogenic comparisons highlight differences that may have implications for vaccine production.
IMPORTANCE Hand-foot-and-mouth disease is a serious public health threat to children in Asian-Pacific countries, resulting in millions of cases. EV71 and CVA16 are the two dominant causative agents of the disease that, while usually mild, can cause severe neurological complications, leading to hundreds of deaths. EV71 vaccines do not provide protection against CVA16. A CVA16 vaccine or bivalent EV71/CVA16 vaccine is therefore urgently needed. We report atomic structures for the mature CVA16 virus, a natural empty particle, and a recombinant CVA16 virus-like particle that does not contain the viral genome. All three particles have similar structures and identical antigenicity. The recombinant particles, produced in insect cells (a system suitable for making vaccine antigen), are stabilized by recruiting from the insect cells a small molecule that is different from that used by the virus in a normal infection. We present structural and immunogenic comparisons with EV71 to facilitate structure-based drug design and vaccine development.
Enterovirus 71 (HEV71) epidemics amongst children and infants result mainly in mild symptoms, however, especially in the Asia-Pacific region, infection can be fatal. At present no therapies are available. We have used structural analysis of the complete virus to guide the design of HEV71 inhibitors. Analysis of complexes with four 3-(-4-pyridyl)-2-imidazolidinone derivatives with varying anti-HEV71 activities, pinpointed key structure-activity correlates. We then identified additional potentially beneficial substitutions, developed methods to reliably triage compounds by quantum mechanics-enhanced ligand docking, and synthesized two candidates. Structural analysis and in vitro assays confirmed the predicted binding modes and their ability to block viral infection. One ligand (IC50 = 25 pM) is an order of magnitude more potent than the best previously reported inhibitor, and is also more soluble. Our approach may be useful in the design of effective drugs for enterovirus infections.
The genus Penicillium phylogenetically belongs to Trichocomaceae, with approximately 300 reported species. The majority of these species are saprobic and commonly occur in soil. This paper reports the genome sequence of Penicillium capsulatum strain ATCC 48735, a rare Penicillium species used in paper manufactories and that was recently reported as a human-invasive opportunist.
Comparison of the immunogenicity response and resistance to challenge in the modified intracerebral challenge assay induced by various acellular pertussis vaccines showed that these were not closely linked. The immunogenicity assay was effective for confirming the presence of specific antigenic components and was invaluable for detecting minor components present in co-purified vaccines. However, the magnitude of antibody responses was not consistently related to antigen concentration nor did it correlate with protection in the modified intracerebral challenge assay. The immunogenicity assay detected degradation of pertussis toxin and pertactin components but not of filamentous haemagglutinin or fimbriae 2 and 3 in denatured acellular pertussis vaccines. The modified intracerebral challenge assay was effective in detecting antigen degradation in all types of acellular pertussis vaccines including those of European/North American origin but was dominated by the response to pertussis toxin. Aerosol challenge was more sensitive in detecting denaturation of filamentous haemagglutinin or fimbriae. The modified intracerebral challenge assay was the only assay that provided a quantitative indication of protective activity. Both immunogenicity and challenge assays provided useful data on acellular pertussis vaccine properties but were complementary and not alternatives.
acellular pertussis vaccines; immunogenicity assay; potency assays; modified Kendrick test; aerosol challenge model
Immunogenicity and safety of the human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine were evaluated in healthy Chinese females aged 9–45 years in 2 phase IIIB, randomized, controlled trials. Girls aged 9–17 years (ClinicalTrials.gov, NCT00996125) received vaccine (n = 374) or control (n = 376) and women aged 26–45 years (NCT01277042) received vaccine (n = 606) or control (n = 606) at months 0, 1, and 6. The primary objective was to show non-inferiority of anti-HPV-16 and -18 immune responses in initially seronegative subjects at month 7, compared with Chinese women aged 18–25 years enrolled in a separate phase II/III trial (NCT00779766). Secondary objectives were to describe the anti-HPV-16 and -18 immune response, reactogenicity and safety. At month 7, immune responses were non-inferior for girls (9–17 years) vs. young women (18–25 years): the upper limit of the 95% confidence interval (CI) for the geometric mean titer (GMT) ratio (women/girls) was below the limit of 2 for both anti-HPV-16 (0.37 [95% CI: 0.32, 0.43]) and anti-HPV-18 (0.42 [0.36, 0.49]). Immune responses at month 7 were also non-inferior for 26–45 year-old women vs. 18–25 year-old women: the upper limit of the 95% CI for the difference in seroconversion (18–25 minus 26–45) was below the limit of 5% for both anti-HPV-16 (0.00% [–1.53, 1.10]) and anti-HPV-18 (0.21% [–1.36, 1.68]). GMTs were 2- to 3-fold higher in girls (9–17 years) as compared with young women (18–25 years). The HPV-16/18 AS04-adjuvanted vaccine had an acceptable safety profile when administered to healthy Chinese females aged 9–45 years.
China; HPV-16/18 AS04-adjuvanted vaccine; cervical cancer; female; human papillomavirus; immunogenicity; safety
Background: Mumps, a communicable, acute and previously well-controlled disease, has had recent and occasional resurgences in some areas.
Methods: A randomized, double-blind, controlled and multistep phase I study of an F-genotype attenuated mumps vaccine produced in human diploid cells was conducted. A total of 300 subjects were enrolled and divided into 4 age groups: 16–60 years, 5–16 years, 2–5 years and 8–24 months. The groups were immunized with one injection per subject. Three different doses of the F-genotype attenuated mumps vaccine, A (3.5 ± 0.25 logCCID50), B (4.25 ± 0.25 logCCID50) and C (5.0 ± 0.25 logCCID50), as well as a placebo control and a positive control of a licensed A-genotype vaccine (S79 strain) were used. The safety and immunogenicity of this vaccine were compared with those of the controls.
Results: The safety evaluation suggested that mild adverse reactions were observed in all groups. No serious adverse event (SAE) was reported throughout the trial. The immunogenicity test showed a similar seroconversion rate of the neutralizing and ELISA antibody in the 2- to 5-year-old and 8- to 24-month-old groups compared with the seroconversion rate in the positive control. The GMT of the neutralizing anti-F-genotype virus antibodies in the vaccine groups was slightly higher than that in the positive control group.
Conclusions: The F-genotype attenuated mumps vaccine evaluated in this clinical trial was demonstrated to be safe and have effective immunogenicity vs. control.
F genotype attenuated mumps vaccine; Phase I clinical trial; safety; immunogenicity
Pertussis remains an important cause of infant death worldwide and is an ongoing public health concern even in countries with high vaccination coverage. A cross-sectional seroepidemiological study was undertaken to estimate true incidence rates and gain further insight into the epidemiology and burden of pertussis in China. During 2011, a total of 1080 blood samples were obtained from healthy individuals between 0 and 86 y of age in Zhengzhou, Central China. Serum IgG antibodies against pertussis toxin (PT) and filamentous hemagglutinin (FHA) were measured quantitatively using ELISA. The results showed that the geometric mean titers of PT and FHA IgG were 6.48 IU/mL (95% CI: 5.70–7.41 IU/mL) and 11.39 IU/mL (95% CI: 10.22–12.87 IU/mL) among subjects less than 4 y of age, indicating that pertussis antibody levels were low despite high vaccination coverage. Of the 850 subjects ≥4 y of age, 56 (6.6%) had anti-PT IgG titers above 30 IU/mL, and 11 (1.3%) had antibodies titers above 80 IU/mL. The estimated age-specific incidence of infection with B. pertussis revealed a peak incidence in the 31 to 40 y age group, followed by the 41 to 60 y age group. Taken together, these results indicate that pertussis is common in Chinese subjects in Zhengzhou, especially in adults, suggesting that the disease burden is underestimated in China. Therefore, our study stresses the importance of strengthening the diagnostic capacity and improving surveillance system for delineating current epidemiological profiles of pertussis. Most importantly, it may be advisable to re-evaluate the current Chinese pertussis immunization schedule and implement to booster doses for older children, adolescents and adults.
pertussis; seroepidemiology; infectious disease; vaccination; China
The objective of this study was to determine the effect of anti-gastrin antiserum in combination with varied dosages of cytotoxic drugs (5-Fluorouracil (5FU) + Cisplatin (CDDP)) in vivo growth of the human gastric cancer cell-line, SGC-7901, which expressed cholecystokininB/gastrin receptors and secreted gastrin. The anti-gastrin antiserum was obtained by immunizing rabbits using a novel immunogen vaccine, which was composed of the common amino-terminal portion of human carboxy-amidated gastrin-17 (G17) and glycine-extended gastrin-17 (gly-G17) and the common carboxy-terminal portion of progastrin (in a 50:50 mixture) all covalently linked to tetanus toxoid (TT) by specific peptide spacers. The antiserum neutralized both G17 and gly-G17 by enzyme-linked immunosorbent assay (ELISA), and a synthetic progastrin peptide, as well, using an E. coli expressed his-tagged progastrin.
The tumor was implanted subcutaneously into the backside of BALB/c nude mice, and the combination antibody-drug treatment using low dose combination chemotherapy had significantly reduced median tumor volumes (62% reduction; p =0.0018) and tumor weights (53% reduction; p =0.0062) when compared to the conventional high dose chemotherapy treated control mice that had a corresponding similar reductive effect, using just the two standard cytotoxic drugs alone; namely by reducing the tumor volumes (65%; p =0.0016) and tumor weights (59% reduction; p=0.0033). Importantly, the immunological treatment had little of the toxicities and side-effects of the full chemotherapy doses alone, which was effected by using a significant decrease in the dosage of chemotherapeutic drugs, while maintaining the same level of efficacy at reduction of tumor growth.
Gastrins; Progastrin; Cancer; Cytotoxic Drugs; Antibody.
Empty virions are inadvertent by-products of recombinant adeno-associated virus (rAAV) packaging process, resulting in vector lots with mixtures of full and empty virions at variable ratios. Impact of empty virions on the efficiency and side-effects of rAAV transduction has not been well characterized. Here, we generated partially and completely empty AAV8 virions, fully packaged rAAV8 lots as well as mixtures of empty and fully packaged virions with variable ratios of empty virions (REVs). The aforementioned dosing formulations of rAAV8 expressing either cellular (EGFP or nuclear-targeted (n) LacZ) or secreted (human α1-antitrypsin, hA1AT) reporter genes were intravenously injected into two different mouse strains, followed by analyses of transgene expressions and serum alanine aminotransferase (ALT) levels at different time points. We found that addition of empty particles to the fixed doses of rAAV8 preparations repressed liver transduction up to 64% (serum hA1AT) and 44% (nLacZ) in C57BL/6 mice, respectively. The similar trend in inhibiting EGFP expression together with concurrent elevations of serum ATL levels were observed in the BALB/c mice, indicating that empty particles may also exacerbate side-effects of rAAV8EGFP transduction. Our results suggest that removal of empty particles from rAAV preparations may improve efficacy and safety of AAV in clinical applications.
rAAV; empty virions; liver gene transfer; side-effect
Maser is an acronym for microwave amplification by stimulated emission of radiation; in astronomy mega-masers are masers in galaxies that are ≥106 times more luminous than typical galactic maser sources. Observational studies of mega-masers can help us to understand their origins and characteristics. More importantly, mega-masers can be used as diagnostic tracers to probe the physical properties of their parent galaxies. Since the late 1970s, only three types of molecules have been found to form mega-masers: H2O, OH and H2CO. Here we report the detection of both SiO and CH3OH mega-masers near the centre of Seyfert 2 galaxy NGC 1068 at millimetre wavelengths, obtained using the IRAM 30-m telescope. We argue that the SiO mega-maser originated from the nuclear disk and the CH3OH mega-maser originated from shock fronts. High-resolution observations in the future will enable us to investigate AGN feedback and determine the masses of central supermassive black holes in such galaxies.
Astrophysical masers are interstellar sources of stimulated spectral line emission, with most SiO masers in the Milky Way existing around evolved stars. Here, Wang et al. report detections of millimetre SiO and Class I CH3OH mega-masers in NGC 1068.
Enterovirus 71 (EV71) is a major pathogen for severe hand, foot and mouth disease (HFMD). Development of vaccines against EV71 would be the most effective approach to prevent the EV71 outbreak. Research and development (R&D) of EV71 vaccine was carried out in several Asian countries. Currently three companies in mainland China have completed Phase III clinical trials of inactivated EV71 whole-virus vaccines, whereas the other two companies have completed Phase I clinical trials separately in Taiwan and in Singapore. Results from those clinical trials have indicated high safety and immunogenicity of EV71 vaccine. Protective efficacies were over 90% on EV71-associated HFMD and over 80% on other EV71-associated diseases. In this paper, we summarize the results from three EV71 vaccine Phase III clinical trials and discuss the challenges of incorporating EV71 vaccine into Expanded Program on Immunization (EPI) in countries with EV71 epidemics.
The Chinese National Institutes for Food and Drug Control (NIFDC) is the national laboratory responsible for the quality control of pharmaceutical products. In recent years, to ensure the quality of biological products and improve the research and development (R&D) of new biological drugs and vaccines, NIFDC conducted a series of regulatory science studies on key technologies for quality control and evaluation, and established a quality control and evaluation platform for biological drugs and vaccines. These studies accelerated the R&D of the biological drugs and vaccines in China and assured their safety and efficacy. In this paper, NIFDC's duties and achievements in the biological drug and vaccine field are summarized.
biotechnology drug; quality control; vaccine
Unlike the well-established picture for the entry of enveloped viruses, the mechanism of cellular entry of non-enveloped eukaryotic viruses remains largely mysterious. Picornaviruses are representative models for such viruses, and initiate this entry process by their functional receptors. Here we present the structural and functional studies of SCARB2, a functional receptor of the important human enterovirus 71 (EV71). SCARB2 is responsible for attachment as well as uncoating of EV71. Differences in the structures of SCARB2 under neutral and acidic conditions reveal that SCARB2 undergoes a pivotal pH-dependent conformational change which opens a lipid-transfer tunnel to mediate the expulsion of a hydrophobic pocket factor from the virion, a pre-requisite for uncoating. We have also identified the key residues essential for attachment to SCARB2, identifying the canyon region of EV71 as mediating the receptor interaction. Together these results provide a clear understanding of cellular attachment and initiation of uncoating for enteroviruses.
Electronic supplementary material
The online version of this article (doi:10.1007/s13238-014-0087-3) contains supplementary material, which is available to authorized users.
viral entry; uncoating; picornaviruses; receptor binding; SCARB2; EV71; lipid transfer tunnel