Silent gene clusters encode magnetic organelle biosynthesis in a non-magnetotactic phototrophic bacterium.

Horizontal gene transfer is a powerful source of innovations in prokaryotes that can affect almost any cellular system, including microbial organelles. The formation of magnetosomes, one of the most sophisticated microbial mineral-containing organelles synthesized by magnetotactic bacteria for magnetic navigation in the environment, was also shown to be a horizontally transferrable trait. However, the mechanisms determining the fate of such genes in new hosts are not well understood, since non-adaptive gene acquisitions are typically rapidly lost and become unavailable for observation. This likely explains why gene clusters encoding magnetosome biosynthesis have never been observed in non-magnetotactic bacteria. Here, we report the first discovery of a horizontally inherited dormant gene clusters encoding biosynthesis of magnetosomes in a non-magnetotactic phototrophic bacterium Rhodovastum atsumiense. We show that these clusters were inactivated through transcriptional silencing and antisense RNA regulation, but retain functionality, as several genes were able to complement the orthologous deletions in a remotely related magnetotactic bacterium. The laboratory transfer of foreign magnetosome genes to R. atsumiense was found to endow the strain with magnetosome biosynthesis, but strong negative selection led to rapid loss of this trait upon subcultivation, highlighting the trait instability in this organism. Our results provide insight into the horizontal dissemination of gene clusters encoding complex prokaryotic organelles and illuminate the potential mechanisms of their genomic preservation in a dormant state.

Diversity of magnetotactic bacteria of the Moskva River.

Diversity of magnetotactic bacteria in the Moskva River at the Strogino area was studied using microscopy and phylogenetic analysis. Magnetotactic cocci were the predominant morphotype. Phylogenetic analysis of the 16S rRNA gene sequences revealed 13 OTUs of the orders Magnetococcales and Rhodospirillales, class Alphaproteobacteria. The shares of the relevant sequences were 90 and 10%, respectively. An axenic culture of magnetotactic spirilla was isolated from the studied community. According to the results of the 16S rRNA gene sequencing, the isolate was identified as a new Magnetospirillum species.

[The bioenergetics system of the blood lymphocytes in infectious-allergic myocarditis]. / Sistema bioénergetiki limfotsitov krovi pri infektsionno-allergicheskom miokardite.

46 patients with infectious-and-allergic myocarditis (IAM) and 46 patients with myocarditic cardiosclerosis (MCS) were studied for cytochemical parameters of blood lymphocyte bioenergetics. In IAM, cellular metabolism was found out to be disturbed, with the activity of G-6-PDG in spontaneous NST-test being risen against the background of depression of NAD- and NADP-diaphorases, lowering of the endogenous cytochrome "C" content and activity of alpha-GPDG. One third of IAM patients demonstrated protracted variant of the disease course by a study into the bioenergetic status of blood lymphocytes. Examination of parameters of blood lymphocytes energy exchange permits establishing more differential and diagnostic criteria for inflammatory lesion of the myocardium.

[Coenzyme metabolic therapy in infectious allergic myocarditis]. / Kofermentnaia metabolicheskaia terapiia pri infektsionno-allergicheskom miokardite.

A trial was performed of clinical efficacy of the coenzyme complex incorporating piridoxalphosphate, cobamamide and phosphaden in patients with infectious allergic myocarditis. Myo- cardial dystrophy and correlations of the myocardial enzymatic status with blood lymphocytes in the above patients were taken in consideration. Corrective action of metabolic therapy on myocardial bioenergy was coupled with positive antiarrhythmic and cardiotonic effects. Cytochemical follow-up investigations enabled long-term monitoring over the patients' condition and further catamnesis.

[The cytochemical characteristics of the blood polymorphonuclear leukocytes in dilated cardiomyopathy and an inflammatory myocardial lesion]. / Tsitokhimicheskaia kharakteristika polimorfnoiadernykh leikotsitov krovi pri dilatsionnoi kardiomiopatii i vospalitel'nom porazhenii miokarda.

Using methods of cytochemical investigation of the blood polymorphonuclear leucocytes (PMNL), parameters have been studied, characterizing the systems of biological defence and bioenergetics in patients with dilated cardiomyopathy (DCMP), infectious allergic myocarditis (IAM) and myocarditic cardiosclerosis (MCS). DCMP patients showed depression of NBT--test against the background of the increase in the cationic proteins (CP) level in the blood PMNLs, which was a major cytochemical feature. G-6-PhDG activity was increased in IAM patients against the background of high values of NBT-test. Increased values for G-6-PhDG, CP, phosphatases in the presence of low levels of myeloperoxidase in the blood PMNL suggest chronic inflammatory process in the myocardium. Investigation into the cytochemical parameters of bioenergetic and biological defence of the blood PMNL in patients with DCMP, IAM and MCS permits optimization of the diagnosis and treatment policy in the aforementioned nosological entities.

[The metabolic characteristics of the blood leukocytes in infectious-allergic myocarditis and dilated cardiomyopathy]. / Metabolicheskie osobennosti leikotsitov krovi pri infektsionno-allergicheskom miokardite i dilatatsionnoi kardiomiopatii.

41 patients with dilated cardiomyopathy (DCMP), 62 patients with infectious allergic myocarditis (IAMC) and 36 patients with myocarditis cardiosclerosis (MCCS) were examined cytochemically. This involved assessment of the activity of alpha-glycerophosphate- and glucose 6-phosphate dehydrogenases, nicotinamide adenine dinucleotide- and nicotinamide adenine dinucleotide phosphate diaphorases, NBT test parameters, measurements of endogenic cytochrome C and cation protein, activity of acid and alkaline phosphatase, lymphocyte peroxidase and that in peripheral blood polymorphonuclear leukocytes. The findings of the study confirmed a close functional and metabolic relation of the above cytochemical indices. This allows their introduction as additional laboratory criteria in differential diagnosis of inflammatory and idiopathic myocardial affections.

[The indices of the proteinase-peroxidase and phosphatase activities of the blood polymorphonuclear leukocytes in the differential diagnosis of dilated cardiomyopathy and idiopathic myocarditis]. / Pokazateli proteinazno-peroksidaznoi i fosfataznoi aktivnosti polimorfno-iadernykh leikotsitov krovi v differential'noi diagnostike dilatatsionnoi kardiomiopatii i idiopaticheskogo miokardita.

The indices of cytochemical activity of the proteinase-peroxidase system and phosphatases of polymorphous-nuclear leucocytes were studied in patients with dilated cardiomyopathy and idiopathic myocarditis. It was found that patients with dilated cardiomyopathy showed an increased level of cationic proteins in polymorphous-nuclear leucocytes while an increase of alkaline phosphatase activity and acid phosphatase against the background of reduction of the cationic protein level and peroxidase activity was characteristic of idiopathic myocarditis. The obtained data allow to use the above cytochemical parameters in the differential diagnosis of noncoronarogenic lesions of the myocardium.

[The cytochemical characteristics of the blood leukocytes in inflammatory lesions of the myocardium]. / Tsitokhimicheskaia kharakteristika leikotsitov krovi pri vospalitel'nykh porazheniiakh miokarda.

Cytochemical investigations were carried out of the activity of peroxidase, nitroblue tetrazolium test and level of cationic proteins in patients with infectious-allergic and myocarditis cardiosclerosis. The activity of peroxidase was reduced in patients with infectious-allergic myocarditis. Patients with infectious-allergic myocarditis and myocarditic cardiosclerosis revealed an increase of the level of cationic proteins. The nitroblue tetrazolium test showed elevated values in the neutrophils and lymphocytes in patients with infectious-allergic myocarditis. In myocarditic cardiosclerosis 15 patients showed an increase of the activity of nitroblue tetrazolium test in lymphocytes. The employed cytochemical methods are of value for the diagnosis of infectious-allergic myocarditis and myocarditic cardiosclerosis.