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

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.

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DSS1 and ssDNA regulate oligomerization of BRCA2

Nucleic Acids Research ◽

10.1093/nar/gkaa555 ◽

2020 ◽

Vol 48 (14) ◽

pp. 7818-7833 ◽

Cited By ~ 1

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.

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Expression of Type IV Pili by Moraxella catarrhalis Is Essential for Natural Competence and Is Affected by Iron Limitation

Infection and Immunity ◽

10.1128/iai.72.11.6262-6270.2004 ◽

2004 ◽

Vol 72 (11) ◽

pp. 6262-6270 ◽

Cited By ~ 48

Author(s):

Nicole R. Luke ◽

Amy J. Howlett ◽

Jianqiang Shao ◽

Anthony A. Campagnari

Keyword(s):

Moraxella Catarrhalis ◽

Pathogenic Bacteria ◽

Type Iv Pili ◽

Protein Subunit ◽

Electron Microscopic ◽

Type Iv ◽

Wide Range ◽

Genes Encoding ◽

Microscopic Studies

ABSTRACT Type IV pili, filamentous surface appendages primarily composed of a single protein subunit termed pilin, play a crucial role in the initiation of disease by a wide range of pathogenic bacteria. Although previous electron microscopic studies suggested that pili might be present on the surface of Moraxella catarrhalis isolates, detailed molecular and phenotypic analyses of these structures have not been reported to date. We identified and cloned the M. catarrhalis genes encoding PilA, the major pilin subunit, PilQ, the outer membrane secretin through which the pilus filament is extruded, and PilT, the NTPase that mediates pilin disassembly and retraction. To initiate investigation of the role of this surface organelle in pathogenesis, isogenic pilA, pilT, and pilQ mutants were constructed in M. catarrhalis strain 7169. Comparative analyses of the wild-type 7169 strain and three isogenic pil mutants demonstrated that M. catarrhalis expresses type IV pili that are essential for natural genetic transformation. Our studies suggest type IV pilus production by M. catarrhalis is constitutive and ubiquitous, although pilin expression was demonstrated to be iron responsive and Fur regulated. These data indicate that additional studies aimed at elucidating the prevalence and role of type IV pili in the pathogenesis and host response to M. catarrhalis infections are warranted.

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The Bacteriophage Pf-10—A Component of the Biopesticide “Multiphage” Used to Control Agricultural Crop Diseases Caused by Pseudomonas syringae

Viruses ◽

10.3390/v14010042 ◽

2021 ◽

Vol 14 (1) ◽

pp. 42

Author(s):

Olesya A. Kazantseva ◽

Rustam M. Buzikov ◽

Tatsiana A. Pilipchuk ◽

Leonid N. Valentovich ◽

Andrey N. Kazantsev ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Gc Content ◽

Microscopic Analysis ◽

Plant Diseases ◽

Host Cells ◽

Agricultural Crop ◽

Electron Microscopic ◽

Bacterial Diseases ◽

Dsdna Molecule ◽

Wide Range

Phytopathogenic pseudomonads are widespread in the world and cause a wide range of plant diseases. In this work, we describe the Pseudomonas phage Pf-10, which is a part of the biopesticide “Multiphage” used for bacterial diseases of agricultural crops caused by Pseudomonas syringae. The Pf-10 chromosome is a dsDNA molecule with two direct terminal repeats (DTRs). The phage genomic DNA is 39,424 bp long with a GC-content of 56.5%. The Pf-10 phage uses a packaging mechanism based on T7-like short DTRs, and the length of each terminal repeat is 257 bp. Electron microscopic analysis has shown that phage Pf-10 has the podovirus morphotype. Phage Pf-10 is highly stable at pH values from 5 to 10 and temperatures from 4 to 60 °C and has a lytic activity against Pseudomonas strains. Phage Pf-10 is characterized by fast adsorption rate (80% of virions attach to the host cells in 10 min), but has a relatively small number of progeny (37 ± 8.5 phage particles per infected cell). According to the phylogenetic analysis, phage Pf-10 can be classified as a new phage species belonging to the genus Pifdecavirus, subfamily Studiervirinae, family Autographiviridae, order Caudovirales.

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

10.1055/s-0039-1684465 ◽

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.

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

Molecular and Cellular Biology ◽

10.1128/mcb.00018-06 ◽

2006 ◽

Vol 26 (16) ◽

pp. 6185-6196 ◽

Cited By ~ 35

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.

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

Molecular and Cellular Biology ◽

10.1128/mcb.21.4.1329-1335.2001 ◽

2001 ◽

Vol 21 (4) ◽

pp. 1329-1335 ◽

Cited By ~ 20

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.

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Pin-Point Transmission Electron Microscopic Analysis Applied to Off-Leakage Failures of a Bipolar Transistor in 0.5μm BiCMOS Devices

ISTFA 1996: Conference Proceedings from the 22nd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa1996p0207 ◽

1996 ◽

Author(s):

M. Okihara ◽

H. Tanaka ◽

N. Hirashita ◽

T. Nakamura ◽

H. Okada ◽

...

Keyword(s):

Large Scale ◽

Ion Beam ◽

Microscopic Analysis ◽

Bipolar Transistor ◽

Specimen Preparation ◽

Preparation Technique ◽

Electron Microscopic ◽

Tem Analysis ◽

Transmission Electron ◽

Wide Range

Abstract Pin-point (specific area) planar transmission electron microscopy (TEM) analysis has been improved to study process-induced defects in recent very large scale integrated (VLSI) devices. The specimens are prepared by a combination of marking failure sites with focused ion beam (FTB) equipment and planar TEM specimen preparation technique. This method provides not only planar observation of localized failures with an accurate observation with high positioning accuracy but also wide range of observable area which is feasible to carry out some application techniques associated with TEM. In particular, it is found to be a powerful method to identify the nature of crystalline defects which cause the failures. This work presents the detailed procedure and demonstrates its successful applicability via studying a leaky bipolar transistor in 0.5μm BiCMOS devices (one failure of more than 4500 transistors). The results clarify the presence of stacking faults, formed during epitaxial growth, between collector and emitter regions in the specific transistor with resistive collector-emitter leakage current.

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Direction of force generated by the inner row of dynein arms on flagellar microtubules.

The Journal of Cell Biology ◽

10.1083/jcb.105.4.1781 ◽

1987 ◽

Vol 105 (4) ◽

pp. 1781-1787 ◽

Cited By ~ 54

Author(s):

L A Fox ◽

W S Sale

Keyword(s):

Beat Frequency ◽

Microscopic Analysis ◽

Force Generation ◽

Electron Microscopic Analysis ◽

Electron Microscopic ◽

Sperm Tail ◽

Relative Direction ◽

Wide Range ◽

Dynein Arms ◽

Definition Of

Our goal was to determine the direction of force generation of the inner dynein arms in flagellar axonemes. We developed an efficient means of extracting the outer row of dynein arms in demembranated sperm tail axonemes, leaving the inner row of dynein arms structurally and functionally intact. Sperm tail axonemes depleted of outer arms beat at half the beat frequency of sperm tails with intact arms over a wide range of ATP concentrations. The isolated, outer arm-depleted axonemes were induced to undergo microtubule sliding in the presence of ATP and trypsin. Electron microscopic analysis of the relative direction of microtubule sliding (see Sale, W. S. and P. Satir, 1977, Proc. Natl. Acad. Sci. USA, 74:2045-2049) revealed that the doublet microtubule with the row of inner dynein arms, doublet N, always moved by sliding toward the proximal end of the axoneme relative to doublet N + 1. Therefore, the inner arms generate force such that doublet N pushes doublet N + 1 tipward. This is the same direction of microtubule sliding induced by ATP and trypsin in axonemes having both inner and outer dynein arms. The implications of this result for the mechanism of ciliary bending and utility in functional definition of cytoplasmic dyneins are discussed.

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

Applied and Environmental Microbiology ◽

10.1128/aem.68.3.1192-1195.2002 ◽

2002 ◽

Vol 68 (3) ◽

pp. 1192-1195 ◽

Cited By ~ 58

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.

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