Rational Utilization of Photoelectrochemistry of Photosystem II for Self-Powered Photocathodic Detection of MicroRNA in Cells

Author(s):  
Li-Bang Zhu ◽  
Hai-Yan Wang ◽  
Tian-Yang Zhang ◽  
Feng-Zao Chen ◽  
De-Man Han ◽  
...  
2019 ◽  
Vol 116 (42) ◽  
pp. 21268-21273 ◽  
Author(s):  
Haruhiko Jimbo ◽  
Taichi Izuhara ◽  
Yukako Hihara ◽  
Toru Hisabori ◽  
Yoshitaka Nishiyama

In photosynthetic organisms, the repair of photosystem II (PSII) is enhanced after acclimation to strong light, with the resultant mitigation of photoinhibition of PSII. We previously reported that oxidation of translation elongation factor EF-Tu, which delivers aminoacyl-tRNA to the ribosome, depresses the repair of PSII in the cyanobacterium Synechocystis sp. PCC 6803. In the present study, we investigated the role of EF-Tu in the repair of PSII after acclimation of Synechocystis to strong light. In cells that had been grown under strong light, both the repair of PSII and the synthesis of proteins de novo were enhanced under strong light, with the resultant mitigation of photoinhibition of PSII. Moreover, levels of EF-Tu were elevated, whereas levels of other components of the translation machinery, such as translation factor EF-G and ribosomal proteins L2 and S12, did not change significantly. The expression of the gene for EF-Tu was induced by light, as monitored at the transcriptional level. Elevation of the level of EF-Tu was strongly correlated with the subsequent enhancement of PSII repair in cells that had been grown under light at various intensities. Furthermore, overexpression of EF-Tu in Synechocystis enhanced protein synthesis and PSII repair under strong light, even after cell culture under nonacclimating conditions. These observations suggest that elevation of the level of EF-Tu might be a critical factor in enhancing the capacity for repair of PSII that develops during acclimation to strong light.


2007 ◽  
Vol 1767 (6) ◽  
pp. 616-623 ◽  
Author(s):  
Marina V. Dudoladova ◽  
Elena V. Kupriyanova ◽  
Alexandra G. Markelova ◽  
Maria P. Sinetova ◽  
Suleyman I. Allakhverdiev ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Sunisa Pansook ◽  
Aran Incharoensakdi ◽  
Saranya Phunpruch

The unicellular halotolerant cyanobacteriumAphanothece halophyticais a potential dark fermentative producer of molecular hydrogen (H2) that produces very little H2under illumination. One factor limiting the H2photoproduction of this cyanobacterium is an inhibition of bidirectional hydrogenase activity by oxygen (O2) obtained from splitting water molecules via photosystem II activity. The present study aimed to investigate the effects of the photosystem II inhibitors carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on H2production ofA.halophyticaunder light and dark conditions and on photosynthetic and respiratory activities. The results showed thatA.halophyticatreated with CCCP and DCMU produced H2at three to five times the rate of untreated cells, when exposed to light. The highest H2photoproduction rates,2.26 ± 0.24and3.63 ± 0.26  μmol H2 g−1dry weight h−1, were found in cells treated with 0.5μM CCCP and 50μM DCMU, respectively. Without inhibitor treatment,A.halophyticaincubated in the dark showed a significant increase in H2production compared with cells that were incubated in the light. Only CCCP treatment increased H2production ofA.halophyticaduring dark incubation, because CCCP functions as an uncoupling agent of oxidative phosphorylation. The highest dark fermentative H2production rate of39.50 ± 2.13  μmol H2 g−1dry weight h−1was found in cells treated with 0.5μM CCCP after 2 h of dark incubation. Under illumination, CCCP and DCMU inhibited chlorophyll fluorescence, resulting in a low level of O2, which promoted bidirectional hydrogenase activity inA.halophyticacells. In addition, only CCCP enhanced the respiration rate, further reducing the O2level. In contrast, DCMU reduced the respiration rate inA.halophytica.


Author(s):  
A. M. Watrach

During a study of the development of infectious laryngotracheitis (LT) virus in tissue culture cells, unusual tubular formations were found in the cytoplasm of a small proportion of the affected cells. It is the purpose of this report to describe the morphologic characteristics of the tubules and to discuss their possible association with the development of virus.The source and maintenance of the strain of LT virus have been described. Prior to this study, the virus was passed several times in chicken embryo kidney (CEK) tissue culture cells.


Author(s):  
Awtar Krishan ◽  
Dora Hsu

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).


Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.


Author(s):  
J. R. Hully ◽  
K. R. Luehrsen ◽  
K. Aoyagi ◽  
C. Shoemaker ◽  
R. Abramson

The development of PCR technology has greatly accelerated medical research at the genetic and molecular levels. Until recently, the inherent sensitivity of this technique has been limited to isolated preparations of nucleic acids which lack or at best have limited morphological information. With the obvious exception of cell lines, traditional PCR or reverse transcription-PCR (RT-PCR) cannot identify the cellular source of the amplified product. In contrast, in situ hybridization (ISH) by definition, defines the anatomical location of a gene and/or it’s product. However, this technique lacks the sensitivity of PCR and cannot routinely detect less than 10 to 20 copies per cell. Consequently, the localization of rare transcripts, latent viral infections, foreign or altered genes cannot be identified by this technique. In situ PCR or in situ RT-PCR is a combination of the two techniques, exploiting the sensitivity of PCR and the anatomical definition provided by ISH. Since it’s initial description considerable advances have been made in the application of in situ PCR, improvements in protocols, and the development of hardware dedicated to in situ PCR using conventional microscope slides. Our understanding of the importance of viral latency or viral burden in regards to HIV, HPV, and KSHV infections has benefited from this technique, enabling detection of single viral copies in cells or tissue otherwise thought to be normal. Clearly, this technique will be useful tool in pathobiology especially carcinogenesis, gene therapy and manipulations, the study of rare gene transcripts, and forensics.


Author(s):  
D. W. Fairbain ◽  
M.D. Standing ◽  
K.L. O'Neill

Apoptosis is a genetically defined response to physiological stimuli that results in cellular suicide. Features common to apoptotic cells include chromatin condensation, oligonucleosomal DNA fragmentation, membrane blebbing, nuclear destruction, and late loss of ability to exclude vital dyes. These characteristics contrast markedly from pathological necrosis, in which membrane integrity loss is demonstrated early, and other features of apoptosis, which allow a non-inflammatory removal of dead and dying cells, are absent. Using heat shock-induced apoptosis as a model for examining stress response in cells, we undertook to categorize a variety of human leukemias and lymphomas with regard to their response to heat shock. We were also interested in determining whether a common temporal order was followed in cells dying by apoptosis. In addition, based on our previous results, we investigated whether increasing heat load resulted in increased apoptosis, with particular interest in relatively resistant cell lines, or whether the mode of death changed from apoptosis to necrosis.


Author(s):  
Neil M. Foster ◽  
Ruth D. Breckon

Macrotubules have been described1 in cells infected with Umatilla virus (UMAV), an orbivirus for which bluetongue virus (BTV) is the protype. Macrotubules, often in linear array, were observed in the cytoplasm and in intimate association with viroplasms of infected cells. Macrotubules had outside and inside diameters of 20 and 15 nm and many had dark-staining centers with diameters similar to the interiors of the tubules. UMAV was 60 nm and the RNA core was 30 nm in diameter. This report describes the association of UMAV with macrotubules and two types of microtubules.


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