Bacterial Ring Research Articles

ПЦР-диагностика возбудителей болезней сортов картофеля (Solanum tuberosum)

When creating technological schemes for the improvement of potatoes, PCR methods are currently actively used, in particular, amplification with hybridization-fluorescence detection in the "real time" and "end point" modes. In this work, both of these methods were applied and the diagnostics of cultivated potato varieties and lines for the presence of viral pathogens A, M, S, X, Y, Andean mottle viruses and latent potato thymovirus (APMV, APLV), as well as tuber spindle viroid (PSTVd) and potato panicle top virus (PMTV) was carried out. The analysis for the presence of parasitic diseases of pale Globodera pallida and golden cyst nematodes Globodera rostochiensis, bacterial ring and brown rot Clavibacter michiganensis subsp. sepedonicus and Ralstonia solanacearum, as well as fungal cancer Synchytrium endobioticum. As a result of PCR analysis, parasitic, fungal and bacterial diseases were not detected 44% of the total number of samples were healthy from viral diseases, while 25% were initially infected and underwent sanitation operations. For the first time, the PCR diagnostic system was introduced into the technological processes for obtaining varietal crops of the Tyumen region, free from diseases, to adapt to growing conditions in Western Siberia.

The antimicrobial activity of as-prepared silver-loaded phosphate glasses and zirconium phosphate

The antimicrobial activities of silver-loaded zirconium phosphate (JDG) and silver-loaded phosphate glasses (ZZB) against Escherichia coli were studied. Although the silver content in JDG was higher than that in ZZB, ZZB suspensions showed better antimicrobial property than JDG suspensions, especially at low concentrations. The antimicrobial activity was analyzed using minimum inhibitory concentrations, bacterial inhibition ring tests, and detection of silver ions in the suspensions. Furthermore, the amounts of silver ions in suspensions with/without bacterial cells were analyzed. Results revealed that only a portion of released silver ions could be adsorbed by E. coli cells, which are critical to cell death. The damaged microstructures of E. coli cells observed by transmission electron microscopy may further prove that the adsorbed silver ions play an important role in the antimicrobial process.

Bio-Wax Latex-Modified Paper as Antimicrobial and Water-Vapor-Resistant Packaging Material

Beeswax and carnauba wax latex particles grafted with antimicrobial agents polyhexamethylene guanidine hydrochloride and polyhexanide were prepared by coupling reaction using N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride as a coupling reagent. As a bifunctional agent for the surface treatment of paper the modified bio-wax latex improved the property of water-vapor resistance and antimicrobial activities of paper significantly after coating. Compared with the control sample the water vapor transmission rate (WVTR) of the paper with coating weight of 12 g/m2 was reduced significantly from 2788.8 g/m2/d to 222.0 g/m2/d (BW-Gly-PHGH) thus demonstrating excellent water vapor barrier performance. The shaking flask method was utilized to investigate the antimicrobial activity against E. coli. The results showed that antimicrobial performance was improved substantially when the amount of added modified bio-wax particles was higher than 20 mg/g fiber. The bacterial inhibition ring test indicated that the antimicrobial mode of the modified bio-wax particles was likely based on the contact mode.

Identification of the SlmA Active Site Responsible for Blocking Bacterial Cytokinetic Ring Assembly over the Chromosome

Bacterial cells use chromosome-associated division inhibitors to help coordinate the processes of DNA replication and segregation with cytokinesis. SlmA from Escherichia coli, a member of the tetracycline repressor (TetR)–like protein family, is one example of this class of regulator. It blocks the assembly of the bacterial cytokinetic ring by interfering with the polymerization of the tubulin-like FtsZ protein in a manner that is dramatically stimulated upon specific DNA binding. Here we used a combination of molecular genetics and biochemistry to identify the active site of SlmA responsible for disrupting FtsZ polymerization. Interestingly, this site maps to a region of SlmA that in the published DNA–free structure is partially occluded by the DNA-binding domains. In this conformation, the SlmA structure resembles the drug/inducer-bound conformers of other TetR–like proteins, which in the absence of inducer require an inward rotation of their DNA-binding domains to bind successive major grooves on operator DNA. Our results are therefore consistent with a model in which DNA-binding activates SlmA by promoting a rotational movement of the DNA-binding domains that fully exposes the FtsZ-binding sites. SlmA may thus represent a special subclass of TetR–like proteins that have adapted conformational changes normally associated with inducer sensing in order to modulate an interaction with a partner protein. In this case, the adaptation ensures that SlmA only blocks cytokinesis in regions of the cell occupied by the origin-proximal portion of the chromosome where SlmA-binding sites are enriched.

Characteristics and host range nodulation of a lysogenic Bradyrhizobium strain of pigeonpea (Cajanus cajan L.) isolated from an Indian soil

A lysogenic strain (A025) and phage indicator (A039) were identified among the bradyrhizobia of pigeonpea (Cajanus cajan). The broth culture of A025 contained a phage (RT2) that showed lytic activity with A039 strain. To confirm their lysogeny (A025), cells were cultured in the presence of 0.01 M sodium citrate, which only killed free phage particles. The treated cell line was grown without sodium citrate, and the culture filtrate formed plaques with A039 strain, but not with A025 strain. Growth kinetics of A025 strain showed that the number of viable cells and cells harboring phage in the culture increased in a parallel manner. Lytic cycle of RT2 phage on A039 strain revealed a latent period of 3 h, with a multiplication period of 6 h and a burst size of 20 particles per cell. Plaques were homogeneously turbid, having a central hallow surrounded by several bacterial rings. Electron micrograph of phage particles showed that the phage had a hexagonal head and short tail. Restriction endonuclease digestion of phage DNA revealed its size of about 41 kbp. Sequence analysis for 16S–23S rDNA and DnaK regions of both strains were aligned with Bradyrhizobium japonicum. Both strains expressed nitrogenase activity in agar-grown culture and formed effective nodules on C. cajan, Macroptilium atropurpureum, Vigna radiata, Vigna unguiculata, and Vigna mungo plants. This is the first report on lysogeny in Bradyrhizobium of C. cajan having a broad host range of nodulation ability.

The Preparation of Carbon Microspheres Loading Silver Antimicrobial Agent and the Study of its Properties

Carbon microspheres (CMSs) were used as the carrier to prepare the Ag-loading CMSs (Ag/CMSs) antibacterial agent through the method of chemical adsorption. The morphologies and structures of modified CMSs were characterized by using the field emission Scanning Electron Microscope (SEM). The results showed that silver was absorbed on the surface of CMSs. The bacterial inhibition ring experiment showed that Ag/CMSs had good antibacterial activity against Staphylococcus aureus and Escherichia coli, meanwhile the diameters of the bacterial inhibition rings were 19 mm against Staphylococcus aureus and 21 mm against Escherichia coli, respectively.

Expression of putative virulence factors in the potato pathogen Clavibacter michiganensis subsp. sepedonicus during infection

The Gram-positive bacterium Clavibacter michiganensis subsp. sepedonicus is the causal agent of bacterial wilt and ring rot of potato. So far, only two proteins have been shown to be essential for virulence, namely a plasmid-encoded cellulase CelA and a hypersensitive response-inducing protein. We have examined the relative expression of CelA and eight putative virulence factors during infection of potato and in liquid culture, using quantitative real-time PCR. The examined putative virulence genes were celB, a cellulase-encoding gene and genes encoding a pectate lyase, a xylanase and five homologues of the Clavibacter michiganensis subsp. michiganensis pathogenicity factor Pat-1 thought to encode a serine protease. Six of the nine assayed genes were up-regulated during infection of potato, including celA, celB, the xylanase gene, and two of the pat genes. The pectate lyase gene showed only slightly elevated expression, whereas three of the five examined pat genes were down-regulated during infection in potato. Interestingly, the two up-regulated pat genes showed a noticeable sequence difference compared to the three down-regulated pat genes. These results reveal several new proteins that are likely to be involved in Clavibacter michiganensis subsp. sepedonicus pathogenicity.

Plastid Division Is Driven by a Complex Mechanism That Involves Differential Transition of the Bacterial and Eukaryotic Division Rings

Plastid Division Is Driven by a Complex Mechanism That Involves Differential Transition of the Bacterial and Eukaryotic Division Rings

The discovery of the division apparatus of plastids and mitochondria

Mitochondria and plastids contain distinct genomes and multiply by binary division of existing organelles. Mitochondrial and plastid division can be clearly separated into two main events: division of the organelle nuclei (nucleoids), and subsequent division of the rest of the organelles, the process of organellokinesis. Organellokinesis makes use of organelle dividing apparatuses such as plastid-dividing ring (PD ring) and mitochondrion-dividing ring (MD ring). The plastid-dividing apparatus (PD apparatus) is composed of three electron-dense rings (the outer, middle and inner), while the mitochondrion-dividing apparatus (MD apparatus) is a pair of electron-dense rings in cytoplasm and inner ring in the mitochondrial matrix. The behaviour of both the PD and MD apparatuses throughout organelle division in Cyanidioschyzon merolae has been studied in detail by electron microscopy. When cells enter mitosis, the inner PD ring forms first, followed by the outer and middle rings and finally the MD rings. The PD rings begin to contract before the MD rings. However, the MD rings start to contract at about 4 times the speed of the PD rings and catch up to the PD rings. The cross-sectional areas of both the outer PD and MD rings increase as contraction in the plane of division progress. This suggests that the outer rings of organelle dividing apparatuses (OD apparatus) provide the motive force for contraction. FtsZ protein is located on the bacterial contractile ring at the equator of dividing bacteria, and controls bacterial division. Since FtsZ contains a tubulin motif, and host eukaryotic organisms and chloroplasts evolved from bacteria, there is debate whether that tubulins found in the cytoskeleton and the inner or outer PD ring evolved from FtsZ protein during eukaryogenesis.

2J1445 バクテリアべん毛基部体FliFリング及びFliF-FliGリングの円筒平均構造

2J1445 バクテリアべん毛基部体FliFリング及びFliF-FliGリングの円筒平均構造

A promising method for eradicating bacterial wilt and ring rot from the potato

A promising method for eradicating bacterial wilt and ring rot from the potato