{"title":"Recent advances in studies on magnetosome-associated proteins composing the bacterial geomagnetic sensor organelle","authors":"Azuma Taoka, Yukako Eguchi, Rino Shimoshige, Yoshihiro Fukumori","doi":"10.1111/1348-0421.13062","DOIUrl":"10.1111/1348-0421.13062","url":null,"abstract":"<p>Magnetotactic bacteria (MTB) generate a membrane-enclosed subcellular compartment called magnetosome, which contains a biomineralized magnetite or greigite crystal, an inner membrane–derived lipid bilayer membrane, and a set of specifically targeted associated proteins. Magnetosomes are formed by a group of magnetosome-associated proteins encoded in a genomic region called magnetosome island. Magnetosomes are then arranged in a linear chain–like positioning, and the resulting magnetic dipole of the chain functions as a geomagnetic sensor for magneto-aerotaxis motility. Recent metagenomic analyses of environmental specimens shed light on the sizable phylogenetical diversity of uncultured MTB at the phylum level. These findings have led to a better understanding of the diversity and conservation of magnetosome-associated proteins. This review provides an overview of magnetosomes and magnetosome-associated proteins and introduces recent topics about this fascinating magnetic bacterial organelle.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9755556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Molecular mechanism of Streptococcus pneumoniae–targeting xenophagy recognition and evasion: Reinterpretation of pneumococci as intracellular bacteria","authors":"Michinaga Ogawa, Sayaka Shizukuishi, Yukihiro Akeda, Makoto Ohnishi","doi":"10.1111/1348-0421.13060","DOIUrl":"10.1111/1348-0421.13060","url":null,"abstract":"<p><i>Streptococcus pneumoniae</i> is a major, encapsulated Gram-positive pathogen that causes diseases including community-acquired pneumonia, meningitis, and sepsis. This pathogen colonizes the nasopharyngeal epithelia asymptomatically but can often migrate to sterile tissues and cause life-threatening invasive infections (invasive pneumococcal disease). Although multivalent pneumococcal polysaccharides and conjugate vaccines are available and effective, they also have major shortcomings with respect to the emergence of vaccine-resistant serotypes. Therefore, alternative therapeutic approaches are needed, and the molecular analysis of host–pathogen interactions and their applications to pharmaceutical development and clinical practice has recently received increased attention. In this review, we introduce pneumococcal surface virulence factors involved in pathogenicity and highlight recent advances in our understanding of host autophagy recognition mechanisms against intracellular <i>S. pneumoniae</i> and pneumococcal evasion from autophagy.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9459248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"γδ T-cell–mediated immune responses to malaria","authors":"Ganchimeg Bayarsaikhan, Yarob Ibraheem, Shin-Ichi Inoue","doi":"10.1111/1348-0421.13059","DOIUrl":"10.1111/1348-0421.13059","url":null,"abstract":"<p>Malaria is one of the deadliest infectious diseases. Licensed vaccine have demonstrated just over 30% efficacy, and therefore, developing new vaccine candidates and understanding immune responses to <i>Plasmodium</i> have become necessary. γδ T cells have been suggested to be associated with immune responses to malaria due to the observation of their expansion in patients with malaria and experimental models of malaria. γδ T cells act as both “innate-like” and “adaptive-like” cells during immune response to malaria. Studies have found that γδ T cells can recognize <i>Plasmodium</i> phosphoantigen, present the antigen, and initiate adaptive immune response during blood-stage <i>Plasmodium</i> infection. Recent reports also suggested the phagocytic and cytotoxic potential of γδ T cells. Furthermore, γδ T cells can provide protection upon immunization with whole parasite. In addition, γδ T cells during the liver-stage infection were able to prevent experimental cerebral malaria. Despite these new findings, questions related to γδ T-cell response during <i>Plasmodium</i> infection remain to be answered. However, investigating these cells in humans remains difficult in many ways; in this regard, rodent models of malarial infection enable us to study these cells in more detail. Insights from experimental malaria models give rise to new cues for development of malarial vaccine and adjunctive therapy for severe malaria. Here, we review our current knowledge of γδ T-cell immune function in human and experimental mouse malarial infection models; especially, we focus on the mechanisms underlying γδ T cells that are associated with protective immunity during malarial infection.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9755541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abdullah A. K. Alzahrani, Yasser A. Altalhi, Ahmed A. S. Alghamdi, Samah M. Muhandis, Daifallah M. Al Aboud, Gaber M. G. Shehab, Ahmed S. Abdel-Moneim
{"title":"Premarital screening of the viral hepatitis among Saudi nationals","authors":"Abdullah A. K. Alzahrani, Yasser A. Altalhi, Ahmed A. S. Alghamdi, Samah M. Muhandis, Daifallah M. Al Aboud, Gaber M. G. Shehab, Ahmed S. Abdel-Moneim","doi":"10.1111/1348-0421.13058","DOIUrl":"10.1111/1348-0421.13058","url":null,"abstract":"<p>Blood borne sexually transmitted infections are among the most serious health problems worldwide. Many people possessing these infections do not have symptoms and may remain undiagnosed. The current study aimed to screen premaritally the incidence of blood borne viruses among Saudi nationals. A retrospective longitudinal study was conducted, using a total of 91,000 medical records, in the blood bank from a single center in the Western region of Saudi Arabia. All persons who underwent premarital examination during the period 2016–2021 for the presence of hepatitis B and C viruses as a part of the national screening program in Saudi Arabia were included in the study. Serological tests were used to screen the presence of HBc Ab and HBs Ag. Both anti-HCV antibodies and the presence of virus RNA using real-time reverse transcriptase polymerase chain reaction (RT-PCR) were also performed. The study reported the presence of 378/91000 (0.42%) infections with hepatitis B virus (HBV) as indicated by the presence of HBc Ab and HBs Ag. Meanwhile, 208 (0.23%) cases were found to be exposed to HCV including 49/91000 (0.05%) active HCV cases, positive for the HCV RNA, while 159/91000 (0.17%) persons were found to possess positive HCV antibodies in the absence of detectable HCV RNA. It was concluded that there is a low prevalence of HBV and HBV among Saudi citizens who were subjected to premarital screening.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9395577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The autotransporter BafA contributes to the proangiogenic potential of Bartonella elizabethae","authors":"Natsumi Suzuki, Kayo Kumadaki, Kaoru Tatematsu, Yohei Doi, Kentaro Tsukamoto","doi":"10.1111/1348-0421.13057","DOIUrl":"10.1111/1348-0421.13057","url":null,"abstract":"<p><i>Bartonella elizabethae</i> is a rat-borne zoonotic bacterium that causes human infectious endocarditis or neuroretinitis. Recently, a case of bacillary angiomatosis (BA) resulting from this organism was reported, leading to speculation that <i>B. elizabethae</i> may also trigger vasoproliferation. However, there are no reports of <i>B. elizabethae</i> promoting human vascular endothelial cell (EC) proliferation or angiogenesis, and to date, the effects of this bacterium on ECs are unknown. We recently identified a proangiogenic autotransporter, BafA, secreted from <i>B. henselae</i> and <i>B. quintana</i>, which are recognized as <i>Bartonella</i> spp. responsible for BA in humans. Here, we hypothesized that <i>B. elizabethae</i> also harbored a functional <i>bafA</i> gene and examined the proangiogenic activity of recombinant <i>B. elizabethae</i>–derived BafA. The <i>bafA</i> gene of <i>B. elizabethae</i>, which was found to share a 51.1% amino acid sequence identity with BafA of <i>B. henselae</i> and 52.5% with that of <i>B. quintana</i> in the passenger domain, was located in a syntenic region of the genome. The recombinant protein of the N-terminal passenger domain of <i>B. elizabethae</i>-BafA facilitated EC proliferation and capillary structure formation. Furthermore, it upregulated the receptor signaling pathway of vascular endothelial growth factor, as observed in <i>B. henselae</i>-BafA. Taken together, <i>B. elizabethae</i>–derived BafA stimulates human EC proliferation and may contribute to the proangiogenic potential of this bacterium. So far, functional <i>bafA</i> genes have been found in all BA-causing <i>Bartonella</i> spp., supporting the key role BafA may play in BA pathogenesis.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9403343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Promising whole-cell vaccines against cryptococcosis","authors":"Keigo Ueno, Soichiro Tsuge, Kiminori Shimizu, Yoshitsugu Miyazaki","doi":"10.1111/1348-0421.13056","DOIUrl":"10.1111/1348-0421.13056","url":null,"abstract":"<p>Cryptococcosis is a mycosis caused by <i>Cryptococcus neoformans</i> and <i>C. gattii</i> species complexes. Although this infection is potentially lethal, no prophylactic vaccine is yet commercially available, and the immune memory that enables prevention is still under investigation. These pathogens have a capsule layer for immune evasion and a sophisticated mechanism to advance the infection, and it is expected that these characteristics will make it difficult to develop prophylactic vaccines and to decipher the protective immunity. The current vaccine studies are focused on subunit, mRNA, DNA, and viral vector vaccines, with whole-cell vaccines also proving successful against cryptococcal infections. Cryptococcal whole-cell vaccines have been composed of highly immunostimulating strains with low-pathogenicity that are modified by genetic recombination technology. Examples include the whole-cell vaccines H99γ, sgl1∆, fbp1∆, znf2<sup>oe</sup>, cda1/2/3∆, cap59∆, and cap60∆. Some of these whole-cell vaccines were found to be highly effective in prolonging life and suppressing the fungal burden after an infection challenge in mice, and to be cross-reactive to <i>C. neoformans</i>, <i>C. gattii</i>, and other fungal pathogens. Furthermore, for some vaccines, the protective effect can be retained even in an immunocompromised host depleted of CD4<sup>+</sup> T cells. These findings have provided new insights into protective immunity that should aid in vaccine development. In this review, we highlight the upsides and downsides of whole-cell vaccines against cryptococcosis.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9755529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issue Information – Cover","authors":"","doi":"10.1111/1348-0421.12989","DOIUrl":"https://doi.org/10.1111/1348-0421.12989","url":null,"abstract":"<p><b>Cover photograph</b>: Screening of target cells. Schematic of the RGA assay for assessing the ADCC activity of anti-RABV antibodies. This figure was created in BioRender.com. <i>Microbiol Immunol: 67:69–78</i>. Article link here\u0000 \u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1348-0421.12989","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50120322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Emergence of Vibrio parahaemolyticus serotype O10:K4 in Thailand","authors":"Kazuhisa Okada, Amonrattana Roobthaisong, Suthida Muangnoicharoen Hearn, Pilailuk Akkapaiboon Okada, Pawinee Doung-Ngern, Warawan Wongboot, Atchareeya Nakkarach, Masatomo Morita, Toshio Kodama, Tetsuya Iida","doi":"10.1111/1348-0421.13055","DOIUrl":"10.1111/1348-0421.13055","url":null,"abstract":"<p>An emerging serotype O10:K4 of <i>Vibrio parahaemolyticus</i> has been predominantly isolated from outbreaks and sporadic cases in China. Herein, we report the first case of infection due to <i>V. parahaemolyticus</i> O10:K4 isolated from a hospitalized patient with acute diarrhea in Thailand. We sequenced the whole genome of the O10:K4 strain and compared it with those of the pandemic O3:K6 strain, O10:K4 strains in China, and other clinical and environmental strains. The results suggested that the O10:K4 strains are not a mere serotype variant diverged from the pandemic O3:K6 strain, confirming that the O10:K4 strain emergence has spread to Southeast Asia.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9609502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A novel toxin–antitoxin system swpAB alters gene expression patterns and reduces virulence expression in enterohemorrhagic Escherichia coli","authors":"Shinya Ebihara, Hilo Yen, Toru Tobe","doi":"10.1111/1348-0421.13054","DOIUrl":"10.1111/1348-0421.13054","url":null,"abstract":"<p>Toxin–antitoxin (TA) systems are found widely among many bacteria, including enterohemorrhagic <i>Escherichia coli</i> (EHEC), but their functions are still poorly understood. In this study, we identified and characterized a novel TA system belonging to the <i>relBE</i> family, classified as a type II TA system, found in EHEC. The protein encoded by the toxin gene is homologous to RelE ribonuclease. Using various conditions for increasing the toxin activity, high-level induction of a toxin gene, and repression of an antitoxin gene in wild-type EHEC, we showed that the TA system, named <i>swpAB</i> (switching of gene expression profile), is involved in selective repression of a set of genes, including some virulence genes, and in the reduction of adherence capacity, rather than in suppression of bacterial growth. A detailed analysis of the profiles of RNA levels along sequences at 15 min after high expression of <i>swpA</i> revealed that two virulence genes, <i>espA</i> and <i>tir</i>, were direct targets of the SwpA toxin. These results suggested that the <i>swpAB</i> system can alter gene expression patterns and change bacterial physiological activity without affecting bacterial growth.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9255267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}