Marinomonas mediterranea is a lysogenic bacterium that synthesizes R-bodies

Microbiology ◽  
2003 ◽  
Vol 149 (9) ◽  
pp. 2679-2686 ◽  
Author(s):  
Diana Hernández-Romero ◽  
Patricia Lucas-Elío ◽  
Daniel López-Serrano ◽  
Francisco Solano ◽  
Antonio Sanchez-Amat
Keyword(s):  
Mitomycin C ◽  
Marine Bacterium ◽  
Sea Water ◽  
Free Living ◽  
Gene Encoding ◽  
Transmission Electron ◽  
Extrachromosomal Elements ◽  
Lysogenic Bacterium ◽  
Resistant Strains ◽  
Micro Organisms

The melanogenic marine bacterium Marinomonas mediterranea synthesizes R-bodies as revealed by transmission electron microscopy. These structures were previously described in some obligate symbionts of paramecia and some free-living bacteria, none of which was isolated from sea water. In other micro-organisms, the synthesis of R-bodies has been related to extrachromosomal elements. Accordingly, M. mediterranea induction by mitomycin C or UV radiation resulted in the production of defective phages resembling bacteriocins, indicating that it is a lysogenic bacterium. Two mitomycin-C-resistant strains defective in prophage replication have been isolated. These mutants, and the previously obtained strains ngC1, T102 and T103, the latter mutated in the ppoS gene encoding a sensor histidine kinase, are affected not only in phage replication but also in polyphenol oxidase activities and melanin synthesis, suggesting a relationship between the control of all these processes.

scholarly journals Induction of Multiple Prophages from a Marine Bacterium: a Genomic Approach

2006 ◽  
Vol 72 (7) ◽  
pp. 4995-5001 ◽  
Author(s):  
Feng Chen ◽  
Kui Wang ◽  
Jeneen Stewart ◽  
Robert Belas
Keyword(s):  
Mitomycin C ◽  
Marine Bacterium ◽  
Pcr Amplification ◽  
Pulsed Field Gel Electrophoresis ◽  
Bacterial Genomes ◽  
Dominant Type ◽  
Transmission Electron ◽  
Viral Particles ◽  
Genomic Approach ◽  
Primer Sets

ABSTRACT Approximately 70% of sequenced bacterial genomes contain prophage-like structures, yet little effort has been made to use this information to determine the functions of these elements. The recent genomic sequencing of the marine bacterium Silicibacter sp. strain TM1040 revealed five prophage-like elements in its genome. The genomes of these prophages (named prophages 1 to 5) are approximately 74, 30, 39, 36, and 15 kb long, respectively. To understand the function of these prophages, cultures of TM1040 were treated with mitomycin C to induce the production of viral particles. A significant increase in viral counts and a decrease in bacterial counts when treated with mitomycin C suggested that prophages were induced from TM1040. Transmission electron microscopy revealed one dominant type of siphovirus, while pulsed-field gel electrophoresis demonstrated two major DNA bands, equivalent to 35 and 75 kb, in the lysate. PCR amplification with primer sets specific to each prophage detected the presence of prophages 1, 3, and 4 in the viral lysate, suggesting that these prophages are inducible, but not necessarily to the same level, while prophages 2 and 5 are likely defective or non-mitomycin C-inducible phages. The combination of traditional phage assays and modern microbial genomics provides a quick and efficient way to investigate the functions and inducibility of prophages, particularly for a host harboring multiple prophages with similar sizes and morphological features.

The number of moults in the egg of sealworm, Pseudoterranova decipiens (Nematoda: Ascaridoidea): an ultrastructural study

1995 ◽  
Vol 52 (S1) ◽  
pp. 156-160 ◽  
Author(s):  
Lena N. Measures ◽  
Henry Hong
Keyword(s):  
Sea Water ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Free Living ◽  
Second Stage ◽  
Ultrastructural Evidence ◽  
Pseudoterranova Decipiens ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Transmission Electron Microscopic Analysis

The number of moults in the egg of sealworm, Pseudoterranova decipiens (Nematoda: Ascaridoidea), and other ascaridoids is contentious. Transmission electron microscopic analysis of eggs and free-living larvae of sealworm confirmed that only one moult occurs in the egg. The first-stage larval (L1) cuticle on embryos was first observed in eggs incubated at 15 °C in sea water on day 5 after eggs were dissected from the uterus of sealworm obtained from the stomach of grey seals. There was no ecdysis of this L1 cuticle. A second cuticle began to form beneath the L1 cuticle between day 5 and 12. The second-stage larval (L2) cuticle continued to develop and on day 12 the L2 larva hatched enclosed within the cuticle of the first stage. The L1 cuticle appeared to be partially resorbed during development of the L2 cuticle. This study provides the first ultrastructural evidence of the number of moults that occur in eggs of sealworm.

7,8-dihydroxyflavone-functionalized gold nanoparticles target the arginase enzyme of Leishmania donovani

Nanomedicine ◽  
2021 ◽  
Author(s):  
Pragya Prasanna ◽  
Prakash Kumar ◽  
Saptarshi Mandal ◽  
Tanvi Payal ◽  
Saurabh Kumar ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Leishmania Donovani ◽  
Drug Resistant ◽  
X Ray Diffraction ◽  
High Biological Activity ◽  
Transmission Electron ◽  
Resistant Strains ◽  
Low Cytotoxicity ◽  
Drug Resistant Strains ◽  
Parasite Leishmania

Aim: To analyze the efficacy and possible mechanism of action of 7,8-dihydroxyflavone (DHF) and DHF synthesized gold nanoparticles (GNPs) against the parasite Leishmania donovani. Methods: GNPs were synthesized using DHF and characterized by dynamic light scattering, ζ potential, Fourier transform infrared spectroscopy, transmission electron microscopy and x-ray diffraction. The efficacy of DHF and DHF-GNP were tested against sensitive and drug-resistant parasites. GNP uptake was measured on macrophages by atomic absorption spectroscopy. Results: DHF and DHF-GNP (∼35 nm) were equally effective against sensitive and drug-resistant strains and inhibited the arginase activity of parasites. Increased IFN-γ and reduced IL-12 cytokine response showed a Th1/Th2-mediated cell death in macrophages. Conclusion: The low cytotoxicity and high biological activity of DHF-GNP may be useful for chemotherapy of leishmaniasis.

Experiments on Substrate Selection by Corophium Species: Films and Bacteria on Sand Particles

1964 ◽  
Vol 41 (3) ◽  
pp. 499-511
Author(s):  
P. S. MEADOWS
Keyword(s):  
Ionic Strength ◽  
Sea Water ◽  
Distilled Water ◽  
Substrate Selection ◽  
Corophium Volutator ◽  
Simple Method ◽  
Substrate Preferences ◽  
Solutions Of Electrolytes ◽  
Sand Particles ◽  
Micro Organisms

1. A simple method is described for determining the substrate preferences of Corophium volutator (Pallas) and Corophium arenarium Crawford. 2. If offered a choice of its own substrate with that of the other species each prefers its own. 3. Level of illumination and colour of substrate have little effect on choice. An animal's size and hence its age has little effect on its substrate preferences. 4. C. volutator prefers a substrate previously maintained under anaerobic conditions, C. arenarium vice versa. 5. Treatments which kill, inactivate, or remove micro-organisms render sands unattractive to Corophium. These include boiling, acid-cleaning, drying, and soaking in fixatives or distilled water. Attempts to make these sands attractive again failed. 6. Distilled water, and solutions of the non-electrolytes sucrose and glycerol at the same osmotic pressure as sea water, induce many bacteria to desorb from sand particles; smaller numbers are desorbed in the presence of solutions of electrolytes at the same ionic strength as sea water (NaCl, Na2SO4, KC1, MgSO4, MgCl2, CaCl2). Of all these, only distilled water and solutions of MgCl2 and CaCl2 reduce the attractive properties of sands. Hence the loss of bacteria from the surface of sand grains, though related to the ionic strength and composition of the medium, is not necessarily associated with a substrate becoming unattractive.

The HiPIP from the acidophilic Acidithiobacillus ferrooxidans is correctly processed and translocated in Escherichia coli, in spite of the periplasm pH difference between these two micro-organisms

Microbiology ◽  
2005 ◽  
Vol 151 (5) ◽  
pp. 1421-1431 ◽  
Author(s):  
Patrice Bruscella ◽  
Laure Cassagnaud ◽  
Jeanine Ratouchniak ◽  
Gaël Brasseur ◽  
Elisabeth Lojou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acidithiobacillus Ferrooxidans ◽  
Biochemical Properties ◽  
Gene Encoding ◽  
Iron Sulfur Cluster ◽  
E Coli ◽  
Iron Sulfur ◽  
Sulfur Protein ◽  
Tat System ◽  
Micro Organisms

The gene encoding a putative high-potential iron–sulfur protein (HiPIP) from the strictly acidophilic and chemolithoautotrophic Acidithiobacillus ferrooxidans ATCC 33020 has been cloned and sequenced. This potential HiPIP was overproduced in the periplasm of the neutrophile and heterotroph Escherichia coli. As shown by optical and EPR spectra and by electrochemical studies, the recombinant protein has all the biochemical properties of a HiPIP, indicating that the iron–sulfur cluster was correctly inserted. Translocation of this protein in the periplasm of E. coli was not detected in a ΔtatC mutant, indicating that it is dependent on the Tat system. The genetic organization of the iro locus in strains ATCC 23270 and ATCC 33020 is different from that found in strains Fe-1 and BRGM. Indeed, in A. ferrooxidans ATCC 33020 and ATCC 23270 (the type strain), iro was not located downstream from purA but was instead downstream from petC2, encoding cytochrome c 1 from the second A. ferrooxidans cytochrome bc 1 complex. These findings underline the genotypic heterogeneity within the A. ferrooxidans species. The results suggest that Iro transfers electrons from a cytochrome bc 1 complex to a terminal oxidase, as proposed for the HiPIP in photosynthetic bacteria.

scholarly journals Isolation and Characterization of a Mutant of the Marine Bacterium Alcanivorax borkumensis SK2 Defective in Lipid Biosynthesis

2010 ◽  
Vol 76 (9) ◽  
pp. 2884-2894 ◽  
Author(s):  
Efraín Manilla-Pérez ◽  
Alvin Brian Lange ◽  
Stephan Hetzler ◽  
Marc Wältermann ◽  
Rainer Kalscheuer ◽  
...  
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Marine Bacterium ◽  
Neutral Lipids ◽  
Nile Red ◽  
Dry Weight ◽  
Wax Ester ◽  
Gene Encoding ◽  
Isolation And Characterization ◽  
Key Enzyme

ABSTRACT In many microorganisms, the key enzyme responsible for catalyzing the last step in triacylglycerol (TAG) and wax ester (WE) biosynthesis is an unspecific acyltransferase which is also referred to as wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT; AtfA). The importance and function of two AtfA homologues (AtfA1 and AtfA2) in the biosynthesis of TAGs and WEs in the hydrocarbon-degrading marine bacterium Alcanivorax borkumensis SK2 have been described recently. However, after the disruption of both the AtfA1 and AtfA2 genes, reduced but substantial accumulation of TAGs was still observed, indicating the existence of an alternative TAG biosynthesis pathway. In this study, transposon-induced mutagenesis was applied to an atfA1 atfA2 double mutant to screen for A. borkumensis mutants totally defective in biosynthesis of neutral lipids in order to identify additional enzymes involved in the biosynthesis of these lipids. At the same time, we have searched for a totally TAG-negative mutant in order to study the function of TAGs in A. borkumensis. Thirteen fluorescence-negative mutants were identified on Nile red ONR7a agar plates and analyzed for their abilities to synthesize lipids. Among these, mutant 2 M131 was no longer able to synthesize and accumulate TAGs if pyruvate was used as the sole carbon source. The transposon insertion was localized in a gene encoding a putative cytochrome c family protein (ABO_1185). Growth and TAG accumulation experiments showed that the disruption of this gene resulted in the absence of TAGs in 2 M131 but that growth was not affected. In cells of A. borkumensis SK2 grown on pyruvate as the sole carbon source, TAGs represented about 11% of the dry weight of the cells, while in the mutant 2 M131, TAGs were not detected by thin-layer and gas chromatography analyses. Starvation and lipid mobilization experiments revealed that the lipids play an important role in the survival of the cells. The function of neutral lipids in A. borkumensis SK2 is discussed.

Ultrastructures of Epibiotic Suctorian, Tokophrya huangmeiensis 

Zootaxa ◽  
2018 ◽  
Vol 4521 (1) ◽  
pp. 145
Author(s):  
URFA BIN TAHIR ◽  
DENG QIONG ◽  
WANG ZHE ◽  
LI SEN ◽  
LIU YANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Structural Changes ◽  
Small Subunit ◽  
Free Living ◽  
Transmission Electron ◽  
Small Subunit Ribosomal Dna ◽  
Ribosomal Dna Sequence ◽  
Freshwater Ciliates

Tokophrya species are either free-living or facultative ectosymbiotic suctorians associated with copepods, isopods, mysids, decapods and amphipods. Tokophrya huangmeiensis in particular is found to be epizoic with the redclaw crayfish Cherax quadricarinatus Von Martens, 1868, which has been observed as part of an ongoing investigation of freshwater ciliates biodiversity in Huanggang, Hubei, China (Tahir et al. 2017). This first study on T. huangmeiensis based on morphological features using light microscopy and small subunit ribosomal DNA sequence (Tahir et al. 2017), suggested that more detailed descriptions on the physiological and structural changes of this species should be done. Thus, in this study, we looked at the ultrastructures of T. huangmeiensis using electron microscopy, including both scanning (SEM) and transmission electron microscopy (TEM). 

scholarly journals Ultra-Morphological Changes of Trichophyton Rubrum Treated with Hydroxychavicol

2020 ◽  
Vol 16 (2) ◽  
Author(s):  
P. M. Ridzuan ◽  
Nasir Mohamad ◽  
Salwani Ismail ◽  
Nor Iza A. Rahman ◽  
Sanusi N.A ◽  
...  
Keyword(s):  
Trichophyton Rubrum ◽  
Morphological Changes ◽  
Treated Group ◽  
Fungal Species ◽  
Skin Infections ◽  
Betel Leaf ◽  
Transmission Electron ◽  
Antifungal Potential ◽  
Resistant Strains ◽  
Preliminary Study

Trichophyton rubrum is a common pathogenic fungal species that is responsible for causing infection on human skin, hair and nail. The antifungal-resistant strains complicate the treatment regime. Hydroxychavicol (HC) is one of the main compounds from Piper betel leaf that have antifungal potential and its mechanism of action has not been studied yet. The objective of this preliminary study to determine the antifungal properties of HC against T. rubrum using transmission electron microscope (TEM) on gross and ultrastructure of T. rubrum hypha. T. rubrum was treated with HC and miconazole (MI) at concentrations of 1.25, 2.5, 5 and 10 mg/mL for 1, 3, 5 and 7 days continuously. Generally, fungi structures became more severely damaged at increasing treatment duration. Microscopically, the fungi’s cell wall treated with HC showed a rough surface, shrinkage and demolition similar to the MI treated group. The fungi organelles were also demolished and disorganized. This study revealed that HC has the ability to inhibit T. rubrum growth and has potential to be an antifungal agent for skin infections.

scholarly journals Mitomycin C Inhibits Esophageal Fibrosis by Regulating Cell Apoptosis and Autophagy via lncRNA-ATB and miR-200b

2021 ◽  
Vol 8 ◽  
Author(s):  
Yin Zhang ◽  
Qinge Wang ◽  
Yuping Xu ◽  
Jing Sun ◽  
Yanbo Ding ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Mitomycin C ◽  
Cell Apoptosis ◽  
Optimal Dose ◽  
The Other ◽  
Fibroblast Cells ◽  
Transmission Electron ◽  
Esophageal Strictures ◽  
Related Proteins

Benign esophageal strictures (BESs) frequently results from esophageal fibrosis. The transformation of fibroblasts into fibrocyte is an important cause of fibrosis. The treatment of fibrosis is challenging. Some previous studies have indicated the antifibrotic effect of mitomycin C (MMC). However, the mechanism of action of MMC and its optimal dose for treatment remains unclear. In the present study, the role of MMC in fighting fibrosis and its mechanism was investigated. Human esophageal fibroblast cells (HEFs)were treated without or with MMC, at 2, 5, 10 μg/ml, combining with mimic lncRNA-ATB, miR-200b inhibitor, rapamycin (RAPA), and 3-Methyladenine (3-MA). The cell viability, and cell apoptosis were evaluated. In addition, expression of apoptosis related proteins (caspase8 and caspase3), autophagy related proteins (LC3II and ATG5) and fibrosis related proteins (α-SMA collagen-1 and TGF-β) were also evaluated. Furthermore, autophagosome was observed by transmission electron microscope. Results showed that the expression of lncRNA-ATB was down-regulated and miR-200b was up-regulated after treated with MMC. And MMC induced cell apoptosis and inhibited cell autophagy. On the other hand, RAPA, mimic lncRNA-ATB and miR-200b inhibitor reduced fibrogenic effect of MMC on HEFs. Collectively, this study suggests that MMC inhibited esophageal fibrosis by regulating cell apoptosis and autophagy via downregulating lncRNA-ATB and upregulating miR-200b.

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