scholarly journals Wax Ester Production from n-Alkanes by Acinetobacter sp. Strain M-1: Ultrastructure of Cellular Inclusions and Role of Acyl Coenzyme A Reductase

2002 ◽  
Vol 68 (3) ◽  
pp. 1192-1195 ◽  
Author(s):  
Takeru Ishige ◽  
Akio Tani ◽  
Keiji Takabe ◽  
Kazunori Kawasaki ◽  
Yasuyoshi Sakai ◽  
...  
Keyword(s):  
Microscopic Analysis ◽  
Dry Weight ◽  
Wax Ester ◽  
Electron Microscopic ◽  
Cellular Inclusions ◽  
Ester Formation ◽  
Coa Reductase ◽  
Acyl Coenzyme A ◽  
Optimized Conditions

ABSTRACT Acinetobacter sp. strain M-1 accumulated a large amount of wax esters from an n-alkane under nitrogen-limiting conditions. Under the optimized conditions with n-hexadecane as the substrate, the amount of hexadecyl hexadecanoate in the cells reached 0.17 g/g of cells (dry weight). Electron microscopic analysis revealed that multilayered disk-shaped intracellular inclusions were formed concomitant with wax ester formation. The contribution of acyl-CoA reductase to wax ester synthesis was evaluated by gene disruption analysis.

scholarly journals DSS1 and ssDNA regulate oligomerization of BRCA2

2020 ◽  
Vol 48 (14) ◽  
pp. 7818-7833 ◽  
Author(s):  
Hang Phuong Le ◽  
Xiaoyan Ma ◽  
Jorge Vaquero ◽  
Megan Brinkmeyer ◽  
Fei Guo ◽  
...  
Keyword(s):  
Replication Fork ◽  
Microscopic Analysis ◽  
Filament Formation ◽  
Electron Microscopic ◽  
Microscopic Imaging ◽  
Cellular Events ◽  
Self Association ◽  
Oligomeric Forms

Abstract The tumor suppressor BRCA2 plays a key role in initiating homologous recombination by facilitating RAD51 filament formation on single-stranded DNA. The small acidic protein DSS1 is a crucial partner to BRCA2 in this process. In vitro and in cells (1,2), BRCA2 associates into oligomeric complexes besides also existing as monomers. A dimeric structure was further characterized by electron microscopic analysis (3), but the functional significance of the different BRCA2 assemblies remains to be determined. Here, we used biochemistry and electron microscopic imaging to demonstrate that the multimerization of BRCA2 is counteracted by DSS1 and ssDNA. When validating the findings, we identified three self-interacting regions and two types of self-association, the N-to-C terminal and the N-to-N terminal interactions. The N-to-C terminal self-interaction of BRCA2 is sensitive to DSS1 and ssDNA. The N-to-N terminal self-interaction is modulated by ssDNA. Our results define a novel role of DSS1 to regulate BRCA2 in an RPA-independent fashion. Since DSS1 is required for BRCA2 function in recombination, we speculate that the monomeric and oligomeric forms of BRCA2 might be active for different cellular events in recombinational DNA repair and replication fork stabilization.

scholarly journals A Fatty Acyl Coenzyme A Reductase Promotes Wax Ester Accumulation in Rhodococcus jostii RHA1

2017 ◽  
Vol 83 (20) ◽  
Author(s):  
James Round ◽  
Raphael Roccor ◽  
Shu-Nan Li ◽  
Lindsay D. Eltis
Keyword(s):  
Specific Activity ◽  
Dry Weight ◽  
Fatty Acyl ◽  
Wax Esters ◽  
Wax Ester ◽  
Wild Type ◽  
Considerable Potential ◽  
Commodity Chemicals ◽  
Acyl Coenzyme A ◽  
Rhodococcus Jostii

ABSTRACT Many rhodococci are oleaginous and, as such, have considerable potential for the sustainable production of lipid-based commodity chemicals. Herein, we demonstrated that Rhodococcus jostii RHA1, a soil bacterium that catabolizes a wide range of organic compounds, produced wax esters (WEs) up to 0.0002% of its cellular dry weight during exponential growth on glucose. These WEs were fully saturated and contained primarily 31 to 34 carbon atoms. Moreover, they were present at higher levels during exponential growth than under lipid-accumulating conditions. Bioinformatics analyses revealed that RHA1 contains a gene encoding a putative fatty acyl coenzyme A (acyl-CoA) reductase (FcrA). The purified enzyme catalyzed the NADPH-dependent transformation of stearoyl-CoA to stearyl alcohol with a specific activity of 45 ± 3 nmol/mg · min and dodecanal to dodecanol with a specific activity of 5,300 ± 300 nmol/mg · min. Deletion of fcrA did not affect WE accumulation when grown in either carbon- or nitrogen-limited medium. However, the ΔfcrA mutant accumulated less than 20% of the amount of WEs as the wild-type strain under conditions of nitric oxide stress. A strain of RHA1 overproducing FcrA accumulated WEs to ∼13% cellular dry weight under lipid-accumulating conditions, and their acyl moieties had longer average chain lengths than those in wild-type cells (C17 versus C16). The results provide insight into the biosynthesis of WEs in rhodococci and facilitate the development of this genus for the production of high-value neutral lipids. IMPORTANCE Among the best-studied oleaginous bacteria, rhodococci have considerable potential for the sustainable production of lipid-based commodity chemicals, such as wax esters. However, many aspects of lipid synthesis in these bacteria are poorly understood. The current study identifies a key enzyme in wax ester synthesis in rhodococci and exploits it to significantly improve the yield of wax esters in bacteria. In so doing, this work contributes to the development of novel bioprocesses for an important class of oleochemicals that may ultimately allow us to phase out their unsustainable production from sources such as petroleum and palm oil.

scholarly journals Stimulating and toxic effects of copper and cobalt nanopowders on rice seedlings

2020 ◽  
pp. 42-52
Author(s):  
I. V. Obidina ◽  
G. I. Churilov ◽  
S. D. Polischuk ◽  
A. Yu. Tarara ◽  
S. S. Gomozova ◽  
...  
Keyword(s):  
Chemical Nature ◽  
Microscopic Analysis ◽  
Rice Seedlings ◽  
Electron Microscopic ◽  
Regional Center ◽  
Scientific Equipment ◽  
Wide Range ◽  
Object Of Study ◽  
Positive Effect

Metal nanopowders have a stimulating effect on the growth and development of plants. The biological activity of nanoparticles depends on size, concentration, and chemical composition. Nanoparticles require further study because they have a wide range of applications in medicine and agriculture. Being biocompatible, copper and cobalt can play the role of growth stimulant, are not toxic and can be used for contact with living systems. The object of study was rice, as an economically important culture. The study addressed the effect of cobalt and copper nanoparticles on the germination and development of rice seedlings. The optimal concentration of ultrafine solutions of these nanopowders for pre-sowing treatment of seeds was determined. Although copper and cobalt have different chemical nature, the nanoparticles show similar impact and doze-dependent effect. Minimum concentrations of the nanoparticles had a positive effect on the morphological and biometric indicators of sprouts. The activity of oxidase enzymes was measured and it showed a reversible nature of oxidative stress. An increase in superoxide dismutase activity and a decrease in catalase activity by less than 30% indicates the stress resistance of rice sprouts and the absence of phytotoxic effects of the nanopowders. The presence of these metals in the seedling homogenate was determined to define the toxic effect. The electron microscopic analysis of the partition of metals in the tissues of experimental plants did not reveal significant deviations from control values. The experiments were performed using scientific equipment of Regional Center for Collective Use of Probe Microscopy in Ryazan State Radio Engineering University.

Electron Microscopic Analysis of Subcellular Distribution and Translocation of Ca ION in Human Platelet

1979 ◽  
Author(s):  
M. Kazama ◽  
T. Daimon ◽  
K. Nakamura ◽  
J. Matsuda ◽  
I. Naito ◽  
...  
Keyword(s):  
Subcellular Distribution ◽  
Human Platelet ◽  
Microscopic Analysis ◽  
Clot Retraction ◽  
Potassium Oxalate ◽  
Electron Microscopic ◽  
Platelet Suspension ◽  
Dense Bodies ◽  
Transmission Electron

For the analysis of the subcellular distribution of Ca ion in human platelet, the washed platelet suspension was fixed in the potassium antimonate-OsO4 method or in the potassium oxalate-glutaraldehyde method without post-fixation with OSO4. The STEM-images were observed with scanning image system fitted with the transmission electron microscope without electron staining.The dense deposition of antimonate or oxalate was found in plasmalemma, the membrane of open canalicular system, mitochondria, α-granules and dense bodies. It was revealed with the energy dispersive type electron probe x-ray microanalyzer system that the deposition of oxalate was exclusively composed of Ca.In the process of platelet aggregation with various agents, α-granules and dense bodies were expelled out together with Ca, which suggested the least role of these ion depositions in the aggregation and clot retraction. The translocation of antimonate deposits was not observed in the Verapamil-treated platelets even after the addition of aggregation agents. This phenomenon indicated that this drug inhibited the release of Ca from the Ca-storing organelles. The distribution of Ca was identical in the platelets of a case of thrombasthenia and the translocation of Ca was not observed with the addition of various aggregating agents.

scholarly journals Sleeping Beauty Transposon-Based Phenotypic Analysis of Mice: Lack of Arpc3 Results in Defective Trophoblast Outgrowth

2006 ◽  
Vol 26 (16) ◽  
pp. 6185-6196 ◽  
Author(s):  
Kojiro Yae ◽  
Vincent W. Keng ◽  
Masato Koike ◽  
Kosuke Yusa ◽  
Michiyoshi Kouno ◽  
...  
Keyword(s):  
Microscopic Analysis ◽  
Blastocyst Stage ◽  
Sleeping Beauty ◽  
Cell Periphery ◽  
Phenotypic Analysis ◽  
Electron Microscopic ◽  
Sleeping Beauty Transposon ◽  
Compound Heterozygotes

ABSTRACT The Sleeping Beauty (SB) transposon system has generated many transposon-insertional mutant mouse lines, some of which have resulted in embryonic lethality when bred to homozygosity. Here we report one such insertion mapped to the mouse actin-related protein complex subunit 3 gene (Arpc3). Arpc3 is a component of the Arp2/3 complex, which plays a major role in actin nucleation with Y-shaped branching from the mother actin filament in response to migration signaling. Arpc3 transposon-inserted mutants developed only to the blastocyst stage. In vitro blastocyst culture of Arpc3 mutants exhibited severe spreading impairment of trophoblasts. This phenotype was also observed in compound heterozygotes generated using conventional gene-targeted and transposon-inserted alleles. Arpc3-deficient mutants were shown to lack actin-rich structures in the spreading trophoblast. Electron microscopic analysis demonstrated the lack of mesh-like structures at the cell periphery, suggesting a role of Arpc3 in Y-shaped branching formation. These data indicate the importance of Arpc3 in the Arp2/3 complex for trophoblast outgrowth and suggest that Arpc3 may be indispensable for implantation.

scholarly journals Critical Role of Caenorhabditis elegansHomologs of Cds1 (Chk2)-Related Kinases in Meiotic Recombination

2001 ◽  
Vol 21 (4) ◽  
pp. 1329-1335 ◽  
Author(s):  
Isao Oishi ◽  
Kenji Iwai ◽  
Yukiko Kagohashi ◽  
Hiroko Fujimoto ◽  
Ken-Ichi Kariya ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Critical Role ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Synaptonemal Complex Formation ◽  
Genetic Interference ◽  
Multicellular Organisms ◽  
Critical Process ◽  
Novel Protein

ABSTRACT Although chromosomal segregation at meiosis I is the critical process for genetic reassortment and inheritance, little is known about molecules involved in this process in metazoa. Here we show by utilizing double-stranded RNA (dsRNA)-mediated genetic interference that novel protein kinases (Ce-CDS-1 and Ce-CDS-2) related to Cds1 (Chk2) play an essential role in meiotic recombination inCaenorhabditis elegans. Injection of dsRNA into adult animals resulted in the inhibition of meiotic crossing over and induced the loss of chiasmata at diakinesis in oocytes of F1animals. However, electron microscopic analysis revealed that synaptonemal complex formation in pachytene nuclei of the same progeny of injected animals appeared to be normal. Thus, Ce-CDS-1 and Ce-CDS-2 are the first example of Cds1-related kinases that are required for meiotic recombination in multicellular organisms.

scholarly journals The Glycosylphosphatidylinositol-Anchored Superoxide Dismutase of Scedosporium apiospermum Protects the Conidia from Oxidative Stress

2021 ◽  
Vol 7 (7) ◽  
pp. 575
Author(s):  
Cindy Staerck ◽  
Hajar Yaakoub ◽  
Patrick Vandeputte ◽  
Julie Tabiasco ◽  
Charlotte Godon ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Wall ◽  
Superoxide Dismutase ◽  
Fungal Pathogens ◽  
Microscopic Analysis ◽  
Antioxidant Systems ◽  
Blood Monocytes ◽  
Phagocytic Cells ◽  
Electron Microscopic

Scedosporium species are common fungal pathogens in patients with cystic fibrosis (CF). To colonize the CF lungs, fungi must cope with the host immune response, especially the reactive oxygen species (ROS) released by phagocytic cells. To this aim, pathogens have developed various antioxidant systems, including superoxide dismutases (SODs) which constitute the first-line protection against oxidative stress. Interestingly, one of the S. apiospermum SOD-encoding genes (SODD gene) exhibits a glycosylphosphatidylinositol (GPI) anchor-binding site and encodes a conidial-specific surface SOD. In this study, a SODDΔ mutant was engineered from a non-homologous end joining-deficient strain (KU70Δ) of S. apiospermum. Compared to its parent strain, the double mutant KU70Δ/SODDΔ exhibited increased susceptibility to various oxidizing agents and triazole antifungals. In addition, the loss of SodD resulted in an increased intracellular killing of the conidia by M1 macrophages derived from human blood monocytes, suggesting the involvement of this superoxide dismutase in the evasion to the host defenses. Nevertheless, one cannot disregard an indirect role of the enzyme in the synthesis or assembly of the cell wall components since transmission electron microscopic analysis revealed a thickening of the inner cell wall layer of the conidia. Further studies are needed to confirm the role of this enzyme in the pathogenesis of Scedosporium infections, including the production of a recombinant protein and study of its protective effect against the infection in a mouse model of scedosporiosis.

On the nutrition and metabolism of zooplankton XI. Lipids in Calanus helgolandicus grazing Biddulphia sinensis

1977 ◽  
Vol 57 (2) ◽  
pp. 525-533 ◽  
Author(s):  
J. R. Sargent ◽  
R. R. Gatten ◽  
E. D. S. Corner ◽  
C. C. Kilvington
Keyword(s):  
Brood Size ◽  
Developmental Stages ◽  
Dry Weight ◽  
Wax Esters ◽  
Wax Ester ◽  
Calanoid Copepods ◽  
Lipid Levels ◽  
History Of ◽  
Northern Pacific

Many of the calanoid copepods contain large amounts of neutral lipid that is predominantly wax esters (Lee, Hirota & Barnett, 1971; Lee & Hirota, 1973; Sargent & Garten, 1976). The role of these compounds in the life-history of copepods is particularly well documented for the large Northern Pacific calanoid Euchaeta japonica Marukawa. These animals have their highest levels of total lipid (50% of the dry weight) at stage V, up to 80% being wax esters (Lee, Nevenzel & Lewis, 1974). Wax ester levels are lower in adult females but are high in the eggs, the contents of which are subsequently used during the naupliar stages (Lee et al. 1974). Thus, wax esters accumulated during the later developmental stages provide a fuel for the developing eggs and embryos; from which it follows that the amounts of these lipids present in mature animals are likely to be critical in determining the brood size and survival of the ensuing generation. So far, however, the factors controlling lipid levels in copepods have been poorly understood.

Sign in / Sign up

Export Citation Format

Share Document