25 October 2019, Volume 14 Issue 5

    

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Invited paper
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  Research on human endogenous retrovirus W family in diseases

  LI Xuhang, ZHU Fan

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 259-266. https://doi.org/10.3969/j.issn.1673-6184.2019.05.001

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Human endogenous retroviruses (HERVs) are residues of exogenous retroviruses which have integrated into the human genome millions of years ago, accounting for about 8%-12% of the whole genome. Most HERVs don’t have an intact open reading frame due to mutations, deletions, etc. However, some HERVs can encode viral proteins, for example, Human endogenous retrovirus W(HERV-W), a member of the gamma retrovirus-like family isolated from patients with multiple sclerosis. Syncytin-1, encoded by HERV-W, plays a role in cell fusion and immunoregulation during human placental development. Under physiological conditions, the transcriptional activity of HERV-W is inhibited by epigenetic regulation, for example, hypermethylation, which can be activated by environmental factors such as drugs, radiations and viral infections as well as genetic factors. Several studies found abnormal expression of HERV-W in patients with some cancers, mental illnesses, and autoimmune diseases. Therefore HERV-W may play an important role as “bridge” and “trigger” in the development of diseases. Currently the monoclonal antibody GNbAC1 targeting Syncytin-1 has been used in clinical research of multiple sclerosis, which also has a good application prospect for type 1 diabetes. Further research on HERV-W might provide a valuable way for diagnosis and treatment of certain diseases.
Original Article
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  The charge heterogeneity of murine coronavirus nucleocapsid protein is related to phosphorylation

  WEN Rong, WANG Yuyan, YE Rong

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 267-276. https://doi.org/10.3969/j.issn.1673-6184.2019.05.002

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  The nucleocapsid (N) protein is an essential structural protein of the virus and plays an important role in protecting the viral genome and regulating the process of viral replication. The phosphorylation of N protein of mouse hepatitis virus (MHV), has been proved to be associated with viral transcription, replication and assembly. We found that N protein expressed at late stage rather than early stage in neuro-2a cells infected with MHV-A59 showed a significant charge heterogeneity. Isoelectric focusing electrophoresis showed that the charge of N protein was continuously distributed. Treatment with the protein S-palmitoylation inhibitor 2-BP and the proteasome inhibitor MG-132 showed that viral replication levels were not only associated with N protein electronegativity, but also with the PKCα phosphorylation at S657 and the maintenance of some endoplasmic reticulum components involved in protein modification and degradation. These results suggest that phosphorylation is a factor associated to the heterogeneity and stability of the murine coronavirus N protein.
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  Identification of nucleolus localization sequence in the Core protein of classical swine fever virus

  WU Rui1,2, PAN Zishu2

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 277-281. https://doi.org/10.3969/j.issn.1673-6184.2019.05.003

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  The core protein of classical swine fever virus (CSFV) is a nucleocapsid protein localized in the inner part of virion. The nucleolus localization of nucleocapsid protein of virus in family Flaviviridae plays an important role in virion packaging and virus replication. In this study, recombinant eukaryotic plasmids expressing CSFV Core protein, its truncated and amino acids mutants fused with EGFP were constructed, respectively. Subcellular localization of core protein and its mutants in the transfected PK15 cells were observed under confocal microscopy. We successfully identified the nucleolus localization sequence PESRKKL and its critical amino acids R76K77 in Core protein. Our work will further our understanding of the structure and function of CSFV Core protein and its roles in virion packaging and virus replication.
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  A mycothiol acetyltransferase knockout in Mycobacterium tuberculosis and its biological characteristics

  GE Wenxue, CHEN Run, BAI Jiacheng, DI Yuchang, ZHANG Xuelian

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 282-288. https://doi.org/10.3969/j.issn.1673-6184.2019.05.004

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  Mycothiol is the major low-molecular-mass thiol in M. tuberculosis, which plays an important role in maintaining redox homeostasis. Mycothiol acetyltransferase (MshD) finishes the synthesis process by transferring the acetyl group of Acetyl-CoA to the mycothiol precursor. In order to explore the role of MshD in M. tuberculosis, we constructed a MshD knockout strain with a phage vector-based homologous recombination technology. Compared with the wild strain H37Ra, the knockout had smaller colonies, slower growth rate, decreased biofilm, and was more sensitive to chemical challengers by 5 mmol/L H₂O₂, 0.05% SDS, 50 ℃ heat shock and hypoxic conditions. The above results indicated that the mshD gene played an important role in M. tuberculosis. This study laid the foundation for further revealing the function and mechanism of the gene.
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  Immunogenicity and protective results of DNA vaccine V569 against latent tuberculosis infection in animal models

  SU Haibo, LIU Zijian, ZHOU Yangyang, PENG Baozhou, GONG Qing

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 289-296. https://doi.org/10.3969/j.issn.1673-6184.2019.05.005

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  We constructed the DNA vaccine Ag85B-Rv3425 -Rv2029c-PPE26 (V569) plasmid based on p-VAX1-Ag85B-Rv3425-Rv2029c (A39) and evaluated its immunogenicity in mice. The levels of cellular immunity and humoral immunity against PBS, BCG, p-VAX1-Ag85B (A), p-VAX1-Ag85B-Rv3425 (A3), A39 and V569 were detected by enzyme-linked immunosorbent assay (ELISA) and flow cytometry after vaccination in mice. We found that V569 could trigger stronger Th1 immune response by augmenting the secretion of IFN-γ and significantly improve the CD4^＋/CD8^＋ T cell ratio in immunized mice compared to BCG. In addition, we evaluated the V569 as post-exposure DNA vaccine and found that it reduced bacterial burdens upon reactivation compared to BCG. The protection of V569 against latent TB infection was determined by zebrafish-Mycobacterium marinum latent infection model. In conclusion, V569 DNA vaccine may be a potential candidate DNA vaccine against latent tuberculosis infection.
Case Analysis
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  A case of brain abscesses infected by nocardia asteroids in a child with steroid-resistant nephrotic syndrome

  YU Lichun, LI Qian, CHEN Yuan, WANG Jing, SUN Shuzhen

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 297-302. https://doi.org/10.3969/j.issn.1673-6184.2019.05.006

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  A case of brain abscesses infected by Nocardia asteroids in a child with steroid-resistant nephrotic syndrome was reported. An 8-year-old male patient was clinically diagnosed as primary nephrotic syndrome (steroid-resistant). Renal biopsy pathology showed focal segmental glomerulosclerosis (typical). On the fourth day after Reno puncture, he suffered from persistent high fever, convulsions, and headache. He received anti-infection and anticoagulant treatment, but his health did not improve. Repeat cerebral MRI showed multiple brain abscesses, puncture liquid culture of the brain abscesses confirmed Nocardia asteroids infection. After multiple antibiotics combined glucocorticoid therapy for 2 months, patient conditions improved, including body temperature returned to normal, headache relief, and brain abscess narrowing down. The case indicated that once refractory pyogenic diseases occurred after routine antibiotics therapy in children with nephrotic syndrome receiving corticosteroids and immunosuppressive treatment, nocardiosis and other opportunistic pathogen infections and attentions on the dosage of corticosteroid and immunosuppressants should be considerate at the same time.
Review
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  Pathogenesis and diagnosis of norovirus

  ZHOU Honglu1，TAN Ming2，3，WANG Xuanyi1，4

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 303-309. https://doi.org/10.3969/j.issn.1673-6184.2019.05.007

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  Noroviruses are the most important viral pathogens causing epidemic acute gastroenteritis infecting people of all ages around the world. The viruses are responsible for the most common non-bacterial foodborne outbreaks of diarrhea. Due to the lack of an effective cell culture or small animal research model, the pathogenesis of norovirus infection and illness remains unclear. By contrast, norovirus laboratory diagnostic technologies are well developed. The recent applications of new technologies are further enhancing the development of diagnostic tools to meet the needs of public health and clinical diagnosis and treatment.
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  Understanding the underlying pathogenesis of Alzheimer’s disease from the perspective of gut microbiota

  WANG Hong1, NIU Chen1, WANG Huijing2, ZHAO Chao1,3

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 310-316. https://doi.org/10.3969/j.issn.1673-6184.2019.05.008

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  In the past decade, it has been realized that the diversity and balance of the gut microbiota plays a critical role for health. Gut microbiota and their metabolites interact with the host through a series of biochemical, immunological and physiological processes to affect the homeostasis and health of the host. Many studies have been reported that the disorders of the gut microbiota are associated with neurological diseases. Alzheimer’s disease (AD) is a complex neurodegenerative disease, its susceptibility and development are influenced by age, heredity and epigenetic factors. New evidence suggested that the composition change and translocation of the gut microbiota were associated with the development of AD, but its causal relationship and possible mechanisms need to be explored. Communications between the central nervous system and the gut axis relied mainly on three manners, including direct neural communication, endocrine pathways and immune regulation. Evidence from animal models of fecal microbiota transplantation and probiotic intervention suggested the association of gut microbiota with AD. Exogenous bacterial metabolites can directly impair neuronal function, and induce neuroinflammation to promote the onset of AD. In this review, we focused on the relationship and possible mechanisms of gut microbiota with AD, and provided evidence for possible interventions to prevent AD by improving the structure of gut microbiota.
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  Intestinal phageome and human health

  WANG Yue, CHEN Qian

  JOURNAL OF MICROBES AND INFECTIONS. 2019, 14(5): 317-322. https://doi.org/10.3969/j.issn.1673-6184.2019.05.009

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  As an important component of the intestinal microbial community, phage has colonized in the intestinal tract in a relatively stable state in different life stages. The currently known intestinal phages are mainly DNA phages, most of which exist in the form of prophage. The intestinal phageome can optimize the structure and composition of the microbiota through various mechanisms, and its structural changes are related to various diseases. This paper reviews the research progress of intestinal phage group and human health, and prospects the research methods and development direction in this field.