Biochemical Characterization of Chlorophyll-Free Mitochondria From Pea Leaves

1985 ◽  
Vol 12 (3) ◽  
pp. 219 ◽  
Author(s):  
DA Day ◽  
M Neuburger ◽  
R Douce

Mitochondria from pea leaves were purified by centrifugation on a self-generated Percoll gradient which contained a linear gradient of polyvinylpyrrolidone-25 (0-10%, w/v). The chlorophyll content of the purified mitochondria was less than 1 �g per mg protein. All substrates were rapidly oxidized by these mitochondria, the rate of glycine oxidation being between 200 and 300 nmol O2 min-1 mg-1 protein, depending on the age of the leaves used. These rates did not vary significantly over a period of 20 h, provided NAD+ was supplied exogenously, when the mitochondria were stored on ice. Respiratory control, ADP/O ratios and outer membrane integrity (always more than 95%) were also maintained during storage. The phospholipid composition of the membranes from the leaf mitochondria was virtually identical to that of mitochondria from non-photosynthetic tissues although their lipid to protein ratio was slightly lower. The polypeptide pattern of the membranes from green leaf mitochondria and those from etiolated leaves and hypocotyls were also similar, but marked differences were observed between the matrix proteins from the different tissues. In particular, intensely stained bands at 94, 51,41 and 15.5 kDa which were present in the matrix of green leaf mitochondria were missing or present in much smaller quantities in the non-photosynthetic tissues. This difference was correlated with the ability of the mitochondria to oxidize glycine, suggesting that the four polypeptides may be associated with the glycine decarboxylase complex.

Author(s):  
J. H. Resau ◽  
N. Howell ◽  
S. H. Chang

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.


2011 ◽  
Vol 10 (9) ◽  
pp. M110.006718 ◽  
Author(s):  
Grażyna E. Sroga ◽  
Lamya Karim ◽  
Wilfredo Colón ◽  
Deepak Vashishth

2001 ◽  
Vol 114 (3) ◽  
pp. 463-474 ◽  
Author(s):  
J. Nickerson

Nuclei are intricately structured, and nuclear metabolism has an elaborate spatial organization. The architecture of the nucleus includes two overlapping and nucleic-acid-containing structures - chromatin and a nuclear matrix. The nuclear matrix is observed by microscopy in live, fixed and extracted cells. Its ultrastructure and composition show it to be, in large part, the ribonucleoprotein (RNP) network first seen in unfractionated cells more than 30 years ago. At that time, the discovery of this RNP structure explained surprising observations that RNA, packaged in proteins, is attached to an intranuclear, non-chromatin structure. Periodic and specific attachments of chromatin fibers to the nuclear matrix create the chromatin loop domains that can be directly observed by microscopy or inferred from biochemical experiments. The ultrastructure of the nuclear matrix is well characterized and consists of a nuclear lamina and an internal nuclear network of subassemblies linked together by highly structured fibers. These complex fibers are built on an underlying scaffolding of branched 10-nm filaments that connect to the nuclear lamina. The structural proteins of the nuclear lamina have been well characterized, but the structural biochemistry of the internal nuclear matrix has received less attention. Many internal matrix proteins have been identified, but far less is known about how these proteins assemble to make the fibers, filaments and other assemblies of the internal nuclear matrix. Correcting this imbalance will require the combined application of biochemistry and electron microscopy. The central problem in trying to define nuclear matrix structure is to identify the proteins that assemble into the 10-nm filaments upon which the interior architecture of the nucleus is constructed. Only by achieving a biochemical characterization of the nuclear matrix will we advance beyond simple microscopic observations of structure to a better understanding of nuclear matrix function, regulation and post-mitotic assembly.


FEBS Letters ◽  
2005 ◽  
Vol 579 (30) ◽  
pp. 6879-6884 ◽  
Author(s):  
Sanath Rajapakse ◽  
Katsueki Ogiwara ◽  
Naoharu Takano ◽  
Akihiko Moriyama ◽  
Takayuki Takahashi

Author(s):  
G. Das ◽  
R. E. Omlor

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.


Author(s):  
Robert Williams ◽  
Che-Hung Lee ◽  
Sara E. Quella ◽  
David M. Harlan ◽  
Yuan-Hsu Kang

Monocyte adherence to endothelial or extracellular matrices plays an important role in triggering monocyte activation in extravascular sites of infection, chronic inflammatory disorders, and tissue damage. Migration of monocytes in the tissues involves the response to a chemoattractant and movement by a series of attachments and detachments to the extracellular matrices which are regulated by expression and distribution of specific receptors for the matrix proteins such as fibronectin (FN). The VSAs (very late antigens or beta integrins), a subfamily of the transmembrane heterodimeric integrin receptors, have been thought to play a major role in monocyte adherence to the extracellular matrices and cells. In this subfamily, VLA-5 and VLA-4 are believed to be the most essential integrins mediating monocyte adherence to FN. In the present report, we have established and compared different procedures for morphological evaluation of the expression and distribution of the FN receptors on human monocytes in order to investigate their response to endotoxin or cytokine stimulation.


2014 ◽  
Vol 3 (3) ◽  
pp. 218-225
Author(s):  
R. G. Somkuwar ◽  
M. A. Bhange ◽  
A. K. Upadhyay ◽  
S. D. Ramteke

SauvignonBlanc wine grape was characterized for their various morphological, physiological and biochemical parameters grafted on different rootstocks. Significant differences were recorded for all the parameters studied. The studies on vegetative parameters revealed that the rootstock influences the vegetative growth thereby increasing the photosynthetic activities of a vine. The highest photosynthesis rate was recorded in 140-Ru grafted vine followed by Fercal whereas the lowest in Salt Creek rootstock grafted vines.The rootstock influenced the changes in biochemical constituents in the grafted vine thereby helping the plant to store enough food material. Significant differences were recorded for total carbohydrates, proteins, total phenols and reducing sugar. The vines grafted on1103-Pshowed highest carbohydrates and starch followed by 140-Ru,while the least amount of carbohydrates were recorded in 110-R and Salt Creek grafted vines respectively.Among the different rootstock graft combinations, Fercal showed highest amount of reducing sugar, proteins and phenols, followed by 1103-P and SO4, however, the lowest amount of reducing sugar, proteins and phenols were recorded with 110-R grafted vines.The vines grafted on different rootstocks showed changes in nutrient uptake. Considering this, the physico-biochemical characterization of grafted vine may help to identify particularrootstocks combination that could influence a desired trait in commercial wine grape varieties after grafting.


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