Bacteria associated with orchid roots and microbial production of auxin

Associative bacteria of terrestrial (Paphiopedilum appletonianum) and epiphytic (Pholidota articulata) tropical orchids were investigated. Microbial community of epiphytic plant differed from that of the terrestrial one. Streptomyces, Bacillus, Pseudomonas, Burkholderia, Erwinia and Nocardia strains populated Paphiopedilum roots, whereas Pseudomonas, Flavobacterium, Stenotrophomonas, Pantoea, Chryseobacterium, Bacillus, Agrobacterium, Erwinia, Burkholderia and Paracoccus strains colonized Pholidota roots. Endophytic bacteria populations were represented with less diversity: Streptomyces, Bacillus, Erwinia and Pseudomonas genera were isolated from P. appletonianum, and Pseudomonas, Bacillus, and Flavobacterium genera were isolated from Ph. articulata. Microorganisms produced indole-3-acetic acid (IAA). Variations in its biosynthesis among the strains of the same genus were also observed. The highest auxin level was detected during the stationary growth phase. Biological activity of microbial IAA was proved by treatment of kidney bean cuttings with bacterial supernatants, revealing considerable stimulation of root formation and growth.     

Bacteria associated with the roots of epiphytic orchids

This work is the first to report the isolation and identification of bacteria colonizing the roots of tropical epiphytic orchids Acampe papillosa (Lindl.) Lindl. and Dendrobium moschatum (Buch.-Ham.) Swartz. and bacteria inhabiting inner layers of the aerial and substrate roots of A. papillosa. We showed by the example of this epiphyte that associative bacteria are present in large amounts on the aerial but not substrate roots. We isolated and identified bacteria from the substrate roots of D. moschatum and from its growth substrate (pine bark). The structure of the intercellular matrix of the associative bacteria was studied.     

Crosstalk between the FGFR2 and TP53 genes in breast cancer: data from an association study and epistatic interaction analysis

To evaluate the potential for gene-gene interaction effects in sporadic breast cancer (BC) risk, we studied combinations of the fibroblast growth factor receptor 2 (FGFR2) rs1219648 and tumor protein 53 (TP53) rs1042522, rs1625895, and rs17878362 polymorphisms in BC patients (n=388) and healthy persons (n=275). In addition to a single-locus effect manifested by the association of FGFR2 rs1219648 and TP53 rs1042522 polymorphisms with high BC risk, depending on menopause status (0.001相似文献   

Localization of Associative Cyanobacteria on the Roots of Epiphytic Orchids

This work is the first study of the localization of phototrophic microorganisms in the rhizoplane and velamen of epiphytic orchids, namely, on the aerial and substrate roots of Acampe papillosa and Dendrobium moschatum and on the aerial roots of Phalaenopsis amabilis and Dendrobium phalaenopsis. The composition of the bacterial community on the plant roots depended on the conditions of plant growth. Under conditions simulating the climate of moist tropical forests, the aerial roots proved to be populated with phototrophic microorganisms, among which cyanobacteria predominated. Interlaced fungal hyphae and filamentous cyanobacteria formed a sheath on the surface of the aerial roots. The nitrogen-fixing capacity of the sheath of the aerial roots was studied on the example of P. amabilis.     

Bacillus subtilis var. amyloliquefaciens biosynthesis of extracellular protease possessing coagulase activity and formed under conditions of limiting the nitrogen sources in the medium

An exocellular protease having the activity of coagulase was synthesized by Bacillus subtilis var. amyloliquefaciens when the growth medium contained no nitrogen sources. The removal of a nitrogen source from the medium was found to induce the synthesis of exoproteases by washed bacterial cells. Protein as a sole source of nitrogen in the medium inhibited rather than induced the biosynthesis of proteases possessing the activity of coagulase by the cells. The production of exoproteases with the coagulase activity was inhibited when a mixture of amino acids was used as a sole nitrogen source.     

Molecular-genetic markers in lung cancer diagnostics

The major approaches to different lung cancer marker development are outlined in the review, including genetic, epigenetic, protein, transcryptomic, proteomic, metabolic, and miRNA markers. As far as epigenetic changes are among the earliest events in malignant transformation, methylated markers are thoroughly discussed. Special attention is given to minimally invasive tumor markers, which could be detected in easily accessible biological fluids, because they can be useful for screening and early diagnostics of cancer (before its clinical manifestation) as well as for verification of standard methods of diagnostics. Extracellular nucleic acids, circulating in blood (cirNA), are highlighted as the potential source of material for the early lung cancer diagnostics, prediction of antitumor treatment efficiency, post-treatment monitoring and disease prognosis.     

Characterization of extracellular yeast peptide factors and their stress-protective effect on probiotic lactic acid bacteria

Protective effect of the extracellular peptide fraction (reactivating factors, RF) produced by yeasts of various taxonomic groups (Saccharomyces cerevisiae, Kluyveromyces lactis, Candida utilis, and Yarrowia lipolytica) on probiotic lactic acid bacteria (LAB) Lactobacillus casei, L. acidophilus, and L. reuteri under bile salt (BS)-induced stress was shown. RF of all yeasts were shown to be of peptide nature; the active component of the S. cerevisiae RF was identified as a combination of low-molecular polypeptides with molecular masses of 0.6 to 1.5 kDa. The protective and reactivating effects of the yeast factors were not species-specific and were similar to those of the Luteococcus japonicus subsp. casei RF. In BS-treated cells of the tester bacteria, a protective effect was observed after 10-min preincubation of the LAB cell suspension with yeast RF: the number of surviving cells (CFU) was 2 to 4.5 times higher than in the control. The reactivating effect was observed when RF was added to LAB cell suspensions not later than 15 min after stress treatment. It was less pronounced than the protector effect, with the CFU number 1 to 3 times that of the control. Both the protector and the reactivating effects were most pronounced in the S. cerevisiae and decreased in the row C. utilis > K. lactis > Y. lipolytica. The efficiency of protective action of yeast RF was found to depend on the properties of recipient LAB cells, with the L. casei strain being most sensitive to BS treatment. In both variants, the highest protective effect of RF (increase in the CFU number) was observed for L. acidophilus, while the least pronounced one was observed for L. casei. The reasons for application of the LAB strains combining high stress resistance and high response to stress-protecting metabolites, including RF factors, as probiotics, is discussed.     

Triple Haplotypes of the TP53 Gene in Patients with Diffuse Small B-Cell Lymphoma

Russian Journal of Genetics - The role of genetic susceptibility to the development of lymphoma is confirmed by the accumulating data on common genetic variants of the genes involved in...     

Localization of associative cyanobacteria on the roots of epiphytic orchids

This work is the first study of the localization of phototrophic microorganisms in the rhizoplane and velamen of epiphytic orchids, namely on the aerial and substrate roots of Acampe papillosa and Dendrobium moschatum and on the aerial roots of the Phalaenopsis amabilis and Dendrobium phalaenopsis. The composition of the bacterial community on the plant roots depended on the conditions of plant growth. Under conditions simulating climate of moist tropical forests, the aerial roots proved to be populated with phototrophic microorganisms among which cyanobacteria predominated. Interlaced fungal hyphae and filamentous cyanobacteria formed a sheath on the surface of aerial roots. The nitrogen-fixing capacity of the sheath of aerial roots was studied by the example of P. amabilis.