A novel species is proposed for two strains of methanotrophic bacteria (H2 T and Sakb1) isolated from an acidic (pH 4.3) Sphagnum peat bog lake (Teufelssee, Germany) and an acidic (pH 4.2) tropical forest soil (Thailand), respectively. Cells of strains H2 T and Sakb1 were aerobic, Gramnegative, non-motile, straight or curved rods that were covered by large polysaccharide capsules and contained an intracytoplasmic membrane system typical of type II methanotrophs. They possessed both a particulate and a soluble methane monooxygenase and utilized the serine pathway for carbon assimilation. They were moderately acidophilic organisms capable of growth between pH 4.4 and 7.5 (optimum 5.8-6.2). The most unique characteristic of these strains was the phospholipid fatty acid profile. In addition to the signature fatty acid of type II methanotrophs (18 Aerobic methanotrophic bacteria are capable of utilizing methane as the sole source of carbon and energy. They have been divided into two groups, types I and II, belonging to the Gamma-and Alphaproteobacteria, respectively. These types differ in several phenotypic, chemotaxonomic and genotypic features, including the arrangement of intracytoplasmic membranes (ICMs), the predominant phospholipid fatty acids (PLFAs) and the pathway used for carbon assimilation. Methanotrophic bacteria inhabit a wide range of natural environments of diverse temperature, salinity andAbbreviations: DMDS, dimethyldisulfide; FAME, fatty acid methyl ester; ICM, intracytoplasmic membrane; MDH, methanol dehydrogenase; PLFA, phospholipid fatty acid; pMMO, particulate methane monooxygenase; sMMO, soluble methane monooxygenase.The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequence and partial sequences of the mxaF, mmoX and pmoA genes of Methylocystis heyeri strain H2 T are AM283543-AM283546, respectively.A supplementary figure showing mass spectra of DMDS adducts of 16 : 1 PLFA of strain H2

Multiple sclerosis (MS) is a widespread neurodegenerative autoimmune disease with unknown etiology. It is increasingly evident that, together with pathogenic T cells, autoreactive B cells are among the major players in MS development. The analysis of myelin neuroantigen-specific antibody repertoires and their possible cross-reactivity against environmental antigens, including viral proteins, could shed light on the mechanism of MS induction and progression. A phage display library of single-chain variable fragments (scFvs) was constructed from blood lymphocytes of patients with MS as a potential source of representative MS autoantibodies. Structural alignment of 13 clones selected toward myelin basic protein (MBP), one of the major myelin antigens, showed high homology within variable regions with cerebrospinal fluid MS-associated antibodies as well as with antibodies toward Epstein-Barr latent membrane protein 1 (LMP1). Three scFv clones showed pronounced specificity to MBP fragments 65-92 and 130-156, similar to the serum MS antibodies. One of these clones, designated E2, in both scFv and full-size human antibody constructs, was shown to react with both MBP and LMP1 proteins in vitro, suggesting natural cross-reactivity. Thus, antibodies induced against LMP1 during Epstein-Barr virus infection might act as inflammatory trigger by reacting with MBP, suggesting molecular mimicry in the mechanism of MS pathogenesis.

Representatives of the genus Beijerinckia are known as heterotrophic, dinitrogen-fixing bacteria which utilize a wide range of multicarbon compounds. Here we show that at least one of the currently known species of this genus, i.e., Beijerinckia mobilis, is also capable of methylotrophic metabolism coupled with the ribulose bisphosphate (RuBP) pathway of C 1 assimilation. A complete suite of dehydrogenases commonly involved in the sequential oxidation of methanol via formaldehyde and formate to CO 2 was detected in cell extracts of B. mobilis grown on CH 3 OH. Carbon dioxide produced by oxidation of methanol was further assimilated via the RuBP pathway as evidenced by reasonably high activities of phosphoribulokinase and ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). Detection and partial sequence analysis of genes encoding the large subunits of methanol dehydrogenase (mxaF) and form I RubisCO (cbbL) provided genotypic evidence for methylotrophic autotrophy in B. mobilis.The current definition of the genus Beijerinckia characterizes its members as nonsymbiotic, aerobic, chemo-heterotrophic bacteria with the ability to fix atmospheric dinitrogen (6). Beijerinckia species utilize a wide range of multicarbon compounds, but sugars are the preferred growth substrates. Members of this genus are typical rod-shaped cells with round ends containing polar lipoid bodies. Another distinctive feature of these bacteria is their acid tolerance, which allows them to grow and to fix dinitrogen at pH 3.0 to 4.0. The first isolates of this genus were obtained from acidic soils of tropical regions (1,24). Later studies revealed that these bacteria are widely distributed in both acidic and neutral soils of different tropical and nontropical regions (5). The four recognized species of this genus, i.e., Beijerinckia indica, Beijerinckia mobilis, Beijerinckia derxii, and Beijerinckia fluminensis, were taxonomically described and intensively studied half a century ago. Since that time no further studies into the physiology and metabolism of this group of bacteria have been undertaken.Recently, a novel subgroup of acidophilic serine pathway methanotrophic bacteria that are phylogenetically closely related to the genus Beijerinckia was discovered in acidic Sphagnum peat bogs and forest soils (10, 11, 13). The 16S rRNA sequence similarity values between Beijerinckia spp. and the acidophilic methanotrophs Methylocella and Methylocapsa range from 96.0 to 97.3%, and the representatives of these three genera form a monophyletic cluster within the alphaproteobacteria. Interestingly, methanotrophic and heterotrophic members of this monophyletic cluster possess some morphological similarities and share several physiological characteristics, including acid tolerance and ability to fix dinitrogen. Comparison of 16S rRNA phylogeny with phylogenies based on two different structural genes of nitrogenase (nifH and nifD) has led to the conclusion that these two metabolically different groups of bacteria might have originated from a common ac...

Epstein-Barr virus-associated gastric cancer [EBV-associated GC, EBV( +) GC] is a distinct molecular subtype of gastrointestinal (GI) cancers. It accounts for up to 10% of all molecular subtypes of gastric cancer (GC). It has unique genetic and epigenetic features, which determine its definitive phenotype with male and younger age predominance, proximal stomach localization, and diffuse adenocarcinoma histology. EBV( +) GC also has a unique epigenetic profile and mutational status with frequent mutations of PIK3CA, ARID1A and BCOR, and PD-L1 and PD-L2 amplifications, as well. The aim of this review is to highlight clinical significance of EBV( +) GC and prognostic role of EBV infection, and to determine potentially appropriate drug therapy for this disease.

The genetic structure of EBV LMP1 alleles isolated from tumor, blood, and throat washing samples of 22 nasopharyngeal carcinoma patients, 17 patients with other non-EBV-related tumors of the oral cavity, and 19 blood donors have been studied in representatives of Central Russia and the Republics of Northern Caucasus, regions which are non-endemic for nasopharyngeal carcinoma. The analysis of the LMP1 alleles collected revealed that they practically matched previously described LMP1 variants; however, some characteristic features were also detected. In particular, the G212S substitution in LMP1 isolates investigated was not observed at all. Tumor samples obtained from nasopharyngeal carcinoma and other tumors of the oral cavity did not differ significantly either in the frequency of "high oncogenic" LMP1 alleles with 10 aa and/or 23 aa deletions (LMP1(China1) and/or LMP1(Med+)), nor in the number of 11 aa repeats and the frequency of 5 aa motif insertions. No differences in the frequency of amino acid substitutions between LMP1 alleles obtained from tumor and throat washing samples of both patient groups were also detected. The data obtained may indicate that in both nasopharyngeal carcinoma patients and patients with other tumors of the oral cavity, the EBV strains with similar LMP1 variants are found to persist. This observation allows us to suggest that in non-endemic areas, EBV strains with any LMP1 alleles can initiate the nasopharyngeal carcinoma development but only in those individuals who have a genetic predisposition to the disease and are subjected to specific environmental, and/or dietary factors present in certain geographic areas.