Biodegradation of groundwater pollutants by a combined culture ofMycobacterium vaccaeand aRhodococcussp.

1997 ◽  
Vol 43 (9) ◽  
pp. 841-846 ◽  
Author(s):  
Jason R. Fairlee ◽  
Brian L. Burback ◽  
Jerome J. Perry
Keyword(s):  
Environmental Pollutant ◽  
Cell Fractionation ◽  
Pollutant Degradation ◽  
Mycobacterium Vaccae ◽  
Culture Optimization ◽  
Microbial Ecosystems ◽  
Cellular Components ◽  
Groundwater Pollutant ◽  
Rhodococcus Sp ◽  
Groundwater Pollutants

The catabolism of selected groundwater pollutants by a combined culture of Mycobacterium vaccae and a Rhodococcus sp. (strain R-22) was investigated. The M. vaccae – R-22 combined culture was five times more effective in mineralizing benzene than either organism alone. Mycobacterium vaccae oxidized benzene to phenol, and R-22 catabolized the phenol to cellular components and CO2. Benzene did not support growth of M. vaccae, R-22, or the combined culture. Optimization of ratios of the two species indicated that the maximum mineralization of benzene occurred at an initial ratio of 75% M. vaccae to 25% R-22. Cell fractionation of the combined culture after mineralization of [U-14C]benzene indicated that 10% of the benzene carbon was incorporated into cell material, and of this 45% was present in protein and 20% in nucleic acids. This suggested that minimally one species could utilize the products of benzene as a nutrient source. The M. vaccae – R-22 combined culture catabolized ethylbenzene and chlorobenzene without the accumulation of phenolic intermediates, which are inhibitory to M. vaccae's ability to degrade the parent compounds. This study demonstrates that defined mixed cultures may be useful in studying the effects of environmental pollutant degradation on microbial ecosystems and mineralization of these pollutants by the ecosystem.Key words: biodegradation, groundwater pollutant, Mycobacterium vaccae, Rhodococcus sp.

Dehalogenation by Mycobacterium vaccae JOB-5: role of the propane monooxygenase

1994 ◽  
Vol 40 (3) ◽  
pp. 169-172 ◽  
Author(s):  
Laura A. Vanderberg ◽  
Jerome J. Perry
Keyword(s):  
Chlorinated Hydrocarbons ◽  
Short Chain ◽  
Mycobacterium Vaccae ◽  
Chlorinated Alkanes ◽  
Broad Specificity ◽  
Groundwater Pollutants

Mycobacterium vaccae JOB-5 has an inducible propane monooxygenase that has been implicated in the catabolism of most major groundwater pollutants including trichloroethylene. Propane-grown cells are also induced for the dehalogenation of 1-chlorobutane and other chloroalkanes. 1-Chlorobutane is oxidized to 2-butanol, indicating that subterminal oxidation of 1-chlorobutane resulted in a concomitant release of the chloride. Nonproliferating suspensions of M. vaccae induced for the propane monooxygenase can dehalogenate a variety of chlorinated hydrocarbons including monochlorinated alcohols, dichlorinated short chain alkanes, and several multiple-substituted compounds including trichloroethylene. The results indicate that M. vaccae JOB-5 has a monooxygenase of broad specificity that can dehalogenate an array of halogenated hydrocarbons.Key words: dehalogenation, propane monooxygenase, chlorinated alkanes.

scholarly journals SNAT7 is the primary lysosomal glutamine exporter required for extracellular protein-dependent growth of cancer cells

2017 ◽  
Vol 114 (18) ◽  
pp. E3602-E3611 ◽  
Author(s):  
Quentin Verdon ◽  
Marielle Boonen ◽  
Christopher Ribes ◽  
Michel Jadot ◽  
Bruno Gasnier ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cancer Cells ◽  
Building Blocks ◽  
Extracellular Proteins ◽  
Cell Fractionation ◽  
Lysosomal Storage ◽  
Alternative Source ◽  
Dependent Growth ◽  
Novel Target ◽  
Cellular Components

Lysosomes degrade cellular components sequestered by autophagy or extracellular material internalized by endocytosis and phagocytosis. The macromolecule building blocks released by lysosomal hydrolysis are then exported to the cytosol by lysosomal transporters, which remain undercharacterized. In this study, we designed an in situ assay of lysosomal amino acid export based on the transcription factor EB (TFEB), a master regulator of lysosomal biogenesis that detects lysosomal storage. This assay was used to screen candidate lysosomal transporters, leading to the identification of sodium-coupled neutral amino acid transporter 7 (SNAT7), encoded by the SLC38A7 gene, as a lysosomal transporter highly selective for glutamine and asparagine. Cell fractionation confirmed the lysosomal localization of SNAT7, and flux measurements confirmed its substrate selectivity and showed a strong activation by the lysosomal pH gradient. Interestingly, gene silencing or editing experiments revealed that SNAT7 is the primary permeation pathway for glutamine across the lysosomal membrane and it is required for growth of cancer cells in a low free-glutamine environment, when macropinocytosis and lysosomal degradation of extracellular proteins are used as an alternative source of amino acids. SNAT7 may, thus, represent a novel target for glutamine-related anticancer therapies.

scholarly journals Draft Genome Sequence of the Putative Marine Pathogen Thalassobius sp. I31.1

2019 ◽  
Vol 8 (6) ◽  
Author(s):  
Hilary J. Ranson ◽  
Jason LaPorte ◽  
Edward Spinard ◽  
Andrei Y. Chistoserdov ◽  
Marta Gomez-Chiarri ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Draft Genome ◽  
Homarus Americanus ◽  
Environmental Pollutant ◽  
Draft Genome Sequence ◽  
American Lobster ◽  
Pollutant Degradation ◽  
Content Type ◽  
Shell Disease ◽  
Insight Into

Thalassobius sp. I31.1 is a putative pathogen involved in epizootic shell disease in the American lobster (Homarus americanus). We report here the draft genome sequence for Thalassobius sp. I31.1 and provide insight into its metabolism and links to environmental pollutant degradation.

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

Mitochondrial Reconstructions Based on Serial Thick Sections and HVEM

1975 ◽  
Vol 33 ◽  
pp. 286-287
Author(s):  
Jerome J. Paulin
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Posterior Pole ◽  
Dimensional Structure ◽  
Stereo Imaging ◽  
Thin Sections ◽  
Anatomical Features ◽  
The Past ◽  
Cellular Components ◽  
Mitochondrial Reticulum

Within the past decade it has become apparent that HVEM offers the biologist a means to explore the three-dimensional structure of cells and/or organelles. Stereo-imaging of thick sections (e.g. 0.25-10 μm) not only reveals anatomical features of cellular components, but also reduces errors of interpretation associated with overlap of structures seen in thick sections. Concomitant with stereo-imaging techniques conventional serial Sectioning methods developed with thin sections have been adopted to serial thick sections (≥ 0.25 μm). Three-dimensional reconstructions of the chondriome of several species of trypanosomatid flagellates have been made from tracings of mitochondrial profiles on cellulose acetate sheets. The sheets are flooded with acetone, gluing them together, and the model sawed from the composite and redrawn.The extensive mitochondrial reticulum can be seen in consecutive thick sections of (0.25 μm thick) Crithidia fasciculata (Figs. 1-2). Profiles of the mitochondrion are distinguishable from the anterior apex of the cell (small arrow, Fig. 1) to the posterior pole (small arrow, Fig. 2).

Solving the mechanisms responsible for organelle behavior in vivo by same-cell correlative light and electron microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 14-15
Author(s):  
Conly L. Rieder
Keyword(s):  
Electron Microscopy ◽  
Quantitative Analysis ◽  
Light Microscopy ◽  
Living Cell ◽  
Light And Electron Microscopy ◽  
Time Behavior ◽  
Dynamic Interactions ◽  
Positive Identification ◽  
Cellular Components

The behavior of many cellular components, and their dynamic interactions, can be characterized in the living cell with considerable spatial and temporal resolution by video-enhanced light microscopy (video-LM). Indeed, under the appropriate conditions video-LM can be used to determine the real-time behavior of organelles ≤ 25-nm in diameter (e.g., individual microtubules—see). However, when pushed to its limit the structures and components observed within the cell by video-LM cannot be resolved nor necessarily even identified, only detected. Positive identification and a quantitative analysis often requires the corresponding electron microcopy (EM).

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