scholarly journals Disruption of Firmicutes and Actinobacteria abundance in tomato rhizosphere causes the incidence of bacterial wilt disease

2020 ◽  
Vol 15 (1) ◽  
pp. 330-347 ◽  
Author(s):  
Sang-Moo Lee ◽  
Hyun Gi Kong ◽  
Geun Cheol Song ◽  
Choong-Min Ryu
Keyword(s):  
Bacterial Wilt ◽  
Rhizosphere Soil ◽  
Plant Protection ◽  
Plant Immunity ◽  
Disease Suppression ◽  
Culturable Bacteria ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Individual Strain ◽  
Bacillus Niacini

AbstractEnrichment of protective microbiota in the rhizosphere facilitates disease suppression. However, how the disruption of protective rhizobacteria affects disease suppression is largely unknown. Here, we analyzed the rhizosphere microbial community of a healthy and diseased tomato plant grown <30-cm apart in a greenhouse at three different locations in South Korea. The abundance of Gram-positive Actinobacteria and Firmicutes phyla was lower in diseased rhizosphere soil (DRS) than in healthy rhizosphere soil (HRS) without changes in the causative Ralstonia solanacearum population. Artificial disruption of Gram-positive bacteria in HRS using 500-μg/mL vancomycin increased bacterial wilt occurrence in tomato. To identify HRS-specific and plant-protective Gram-positive bacteria species, Brevibacterium frigoritolerans HRS1, Bacillus niacini HRS2, Solibacillus silvestris HRS3, and Bacillus luciferensis HRS4 were selected from among 326 heat-stable culturable bacteria isolates. These four strains did not directly antagonize R. solanacearum but activated plant immunity. A synthetic community comprising these four strains displayed greater immune activation against R. solanacearum and extended plant protection by 4 more days in comparison with each individual strain. Overall, our results demonstrate for the first time that dysbiosis of the protective Gram-positive bacterial community in DRS promotes the incidence of disease.

Isolation and Identification of Bacteria from Marine Biofilms

2005 ◽  
Vol 277-279 ◽  
pp. 612-617 ◽  
Author(s):  
Yoo Kyung Lee ◽  
Kae Kyoung Kwon ◽  
Kyeung Hee Cho ◽  
Jae Hyun Park ◽  
Hong Kum Lee
Keyword(s):  
Culturable Bacteria ◽  
Bacterial Isolates ◽  
Isolation And Identification ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Rdna Sequences ◽  
Marine Biofilms ◽  
Antifouling Agent ◽  
Identification Of Bacteria ◽  
Invertebrate Larvae

In the marine environment, biofilms cover most of the subtidal and intertidal solid surfaces. Culturable bacteria forming marine biofilms were isolated on artificial substrate called acrylic coupons. The bacterial isolates were identified through a comparison of 16S rDNA sequences. A total of 115 strains were cultured and identified, 45 of which showed the same sequences with other strains. Therefore, 70 strains were finally identified. The bacterial isolates belonged to a–Proteobacteria (32 isolates), g–Proteobacteria (12 isolates), CFB group bacteria (4 isolates), high GC Gram-positive bacteria (9 isolates), and low GC Gram-positive bacteria (13 isolates). The bacterial isolates may be used as standard bacteria to test new antifouling agent. They may also be utilized as useful bacteria to enhance the settlement of commercial algae and invertebrate larvae for aquaculture.

scholarly journals Draft Genome Sequences of 10 Paenibacillus and Bacillus sp. Strains Isolated from Healthy Tomato Plants and Rhizosphere Soil

2019 ◽  
Vol 8 (12) ◽  
Author(s):  
Lu Zhou ◽  
Chunxu Song ◽  
Anne de Jong ◽  
Oscar P. Kuipers
Keyword(s):  
Rhizosphere Soil ◽  
Draft Genome ◽  
Plant Tissues ◽  
Bacillus Sp ◽  
Genome Sequences ◽  
Gram Positive ◽  
Tomato Plants ◽  
Content Type ◽  
Interaction Mechanisms ◽  
Gram Positive Bacteria

In order to investigate the underlying interaction mechanisms between plants and Gram-positive bacteria, 10 Paenibacillus and Bacillus strains were isolated from healthy tomato rhizosphere and plant tissues.

scholarly journals Rhizosphere Bacterial Population Flux in Golf Course Putting Greens in the Southeastern United States

HortScience ◽  
2004 ◽  
Vol 39 (7) ◽  
pp. 1754-1758 ◽  
Author(s):  
M.L. Elliott ◽  
E.A. Guertal ◽  
H.D. Skipper
Keyword(s):  
North Carolina ◽  
South Carolina ◽  
Cynodon Dactylon ◽  
Creeping Bentgrass ◽  
Fluorescent Pseudomonads ◽  
Culturable Bacteria ◽  
Gram Positive ◽  
Putting Greens ◽  
Gram Positive Bacteria ◽  
Heat Tolerant

The rhizospheres of creeping bentgrass (Agrostis palustris Huds.) and hybrid bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy) putting greens were sampled quarterly for 4 years. Six bacterial groups, including total aerobic bacteria, fluorescent pseudomonads, actinomycetes, Gram-negative bacteria, Gram-positive bacteria, and heat-tolerant bacteria, were enumerated. The putting greens were located in four geographic locations (bentgrass in Alabama and North Carolina; bermudagrass in Florida and South Carolina) and were maintained according to local maintenance practices. Significant effects were observed for sampling date, turfgrass species and location, with most variation due to either turfgrass species or location. Bentgrass roots had significantly greater numbers of fluorescent pseudomonads than bermudagrass roots, while bermudagrass roots had significantly greater numbers of Gram-positive bacteria, actinomycetes and heat-tolerant bacteria. The North Carolina or South Carolina locations always had the greatest number of bacteria in each bacterial group. For most sampling dates in all four locations and both turfgrass species, there was a minimum, per gram dry root, of 107 CFUs enumerated on the total aerobic bacterial medium and a minimum of 105 CFUs enumerated on the actinomycete bacterial medium. Thus, it appears that in the southeastern U.S. there are large numbers of culturable bacteria in putting green rhizospheres that are relatively stable over time and geographic location.

Phylogenetic diversity of bacteria isolates from the Qinghai-Tibet Plateau permafrost region

2007 ◽  
Vol 53 (8) ◽  
pp. 1000-1010 ◽  
Author(s):  
Gaosen Zhang ◽  
Fujun Niu ◽  
Xiaojun Ma ◽  
Wei Liu ◽  
Maoxing Dong ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Tibet Plateau ◽  
Permafrost Region ◽  
Culturable Bacteria ◽  
Isolated Populations ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Permafrost Environment ◽  
Colony Forming Units ◽  
Qinghai Tibet Plateau

The Qinghai-Tibet Plateau in east Asia is a unique and important permafrost environment. However, its microbiology remains largely unexplored to date. In this study, sediment samples were collected from the Qinghai-Tibet Plateau permafrost region, bacteria isolation procedures were performed 8 times, and the samples incubated at 4 °C for nearly 3 months. The number of colony forming units (cfu) ranged from 0 to 107/(g dry soil). The quantity of culturable bacteria grew exponentially within the first few weeks, and then slowed gradually to a plateau. Phylogenetic analyses indicated that all the isolates fell into 6 categories: high G+C Gram-positive bacteria, low G+C Gram-positive bacteria, α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, and Cytophaga–Flavobacterium–Bacteroides group bacteria. The isolates belong to 19 genera, but the genera Arthrobacter and Pseudomonas were predominant. With the increase in incubation time, the isolated populations changed in terms of both species and their respective quantities. Of the 33 analyzed isolates, 9 isolates related to 8 genera might be new taxa. These results suggest that the Qinghai-Tibet Plateau permafrost region is a specific ecologic niche that accommodates an original microbial assemblage.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

Antibacterial activity of magnesium oxide nanoparticles prepared by Calcination method

2019 ◽  
Vol 10 (03) ◽  
Author(s):  
Elaf Ayad Kadhem ◽  
Miaad Hamzah Zghair ◽  
Sarah , Hussam H. Tizkam, Shoeb Alahmad Salih Mahdi ◽  
Hussam H. Tizkam ◽  
Shoeb Alahmad
Keyword(s):  
Antibacterial Activity ◽  
Magnesium Oxide ◽  
Diffusion Method ◽  
Oxide Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Magnesium Oxide Nanoparticles ◽  
Agar Disc

magnesium oxide nanoparticles (MgO NPs) were prepared by simple wet chemical method using different calcination temperatures. The prepared NPs were characterized by Electrostatic Discharge (ESD), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). It demonstrates sharp intensive peak with the increase of crystallinty and increase of the size with varying morphologies with respect to increase of calcination temperature. Antibacterial studies were done on gram negative bacteria (E.coli) and gram positive bacteria (S.aureus) by agar disc diffusion method. The zones of inhibitions were found larger for gram positive bacteria than gram negative bacteria, this mean, antibacterial MgO NPs activity more active on gram positive bacteria than gram negative bacteria because of the structural differences. It was found that antibacterial activity of MgO NPs was found it has directly proportional with their concentration.

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