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K S Chiang

Publications and source records attributed to K S Chiang.

At least 37 records · Page 2Linked to original sources
PubMed1978

Isolation and characterization of mitochondrial DNA from Chlamydomonas reinhardtii.

Mitochondrial DNA (mtDNA) has been isolated from a mitochondrial pellet of Chlamydomonas reinhardtii. The mtDNA has a buoyant density of 1.706 g/ml in CsCl, a melting temperature of 87.9 degrees in standard saline citrate, and a nucleoside composition of 47.5% deoxyguanidine plus deoxycytidine with no odd nucleosides. Thermal denaturation and renaturation studies have shown that (i) mtDNA contains no extensive intramolecular heterogeneity nor significant base bias between the complementary polynucleotide chains and (ii) mtDNA renatures as a single homogeneous class with a kinetic complexity of 9.78 X 10(6) daltons. Although rare (less than or equal to 1%), both open and supercoiled circular mtDNA molecules have been observed in the electron microscope. Contour lengths of linear and open and closed circular molecules are all within the range of 4.0-5.4 micron with a mean of 4.67 +/- 0.30 micron. This size is similar to that of animal mtDNA but approximately 1/8 that of the higher plant mtDNAs. The magnitude of mtDNA reiteration in C. reinhardtii is estimated to be of the same order as that of chloroplast DNA.

Centrifugation, Isopycnic↗
PubMed1977

Temporal programming of chloroplast and cytoplasmic ribosomal RNA transcription in the synchronous cell cycle of Chlamydomonas reinhardtii.

Approximately 90% of the Chlamydomonas reinhardtii chloroplast and cytoplasmic rRNAs was transcribed in the nuclear G1 phase, which occurred during the light period under an alternating light-dark synchronization regime of 12 h each. The remaining 10% of chloroplast and cytoplasmic rRNAs was transcribed from its respective DNAs in the dark period, in the midst of an apparent turnover of a transcription appeared to be prokaryotic in sophistication. The transcription was not interrupted during chloroplast DNA synthesis which occurred during the light period. However, transcription of the nuclear DNA was repressed severely during the nuclear S phase in the dark period. The patterns of incorporation of 32P into chloroplast and cytoplasmic rRNA species in the cell cycle were similar to those of the actual rRNA synthesis as measured optically. However, the quantity of 32P incorporation per unit amount of rRNA synthesized varied considerably during the cell cycle, increasing in all rRNA's during the dark period. 32P incorporation data obtained from continuous and pulse 32P-labeling experiments also revealed a turnover of a small amount of both cytoplasmic and chloroplast rRNAs at the end of the S phase. The 32P incorporation into cytoplasmic and chloroplast rRNAs was well matched temporally with the 32P incorporation into their corresponding ribosomes, indicating that the newly synthesized rRNA molecules are utilized without delay throughout the cell cycle in the assembly of ribosomes.

Cell Division↗
PubMed1974

Interaction between mendelian and non-mendelian genes. Regulation of the transmission of non-mendelian genes by a mendelian gene in Chlamydomonas reinhardtii.

The non-Mendelian genetic element of a given mating type of Chlamydomonas reinhardtii was first doubly marked by succesive mutageneses and then transferred into a number of offspring cells of the opposite mating type. In subsequent crosses of these offspring clones, the transmission pattern of the original non-Mendelian markers was analyzed. The results indicate that the mating-type gene of a given cell regulates the transmission and perhaps the recombination of the non-Mendelian genes regardless of whether the non-Mendelian markers were isolated originally in the same cell or obtained from another cell of the opposite mating type through genetic transmission. The regulation of the transmission of non-Mendelian genes in C. reinhardtii is thus apparently different from the autonomous control of the transmission of non-Mendelian mitochondrial genes in yeast by a genetic factor located on the mitochondrial genome.

Chlamydomonas↗
PubMed1971

Heterogeneity, complexity, and repetition of the chloroplast DNA of Chlamydomonas reinhardtii.

The chloroplast DNA of wild-type Chlamydomonas reinhardtii was isolated in a CsCl density gradient as a single, homogeneous density class with a mean density of 1.695 g/cm(3). Irrespective of sheared size, denatured chloroplast DNA renatured as a single homogeneous species. Compositional heterogeneity, presumably intramolecular, was revealed by the absorbance-temperature profile. The complement of unique nucleotide sequences of the chloroplast DNA, as determined by the rate of renaturation, was 1.94 x 10(8) daltons. This kinetic complexity is 26-fold less than the DNA content of a single gamete chloroplast, and 52-fold less than the chloroplast of a vegetative cell, which indicates that the chloroplast of C. reinhardtii possesses at least 26 copies of a unique nucleotide sequence.

Base Sequence↗
PubMedDate not supplied

Management of inferior pancreaticoduodenal artery aneurysms: a 4-year, single center experience.

Inferior pancreaticoduodenal artery aneurysms are uncommon visceral artery aneurysms usually difficult to resect, and, if untreated, have a propensity to rupture with catastrophic results. We reviewed the clinical and treatment records of four patients encountered in our institution within the last 4 years. Three patients presented as bleeding emergencies from single aneurysms and were successfully treated by transcatheter embolization using coaxial technique and a variety of embolic agents. One nonemergent, asymptomatic patient had surgical resection of two inferior pancreaticoduodenal artery aneurysms due to unfavorable anatomy for embolization. Embolization therapy appears to be the treatment of choice in the emergency setting. Patients with unsuitable anatomy for embolization may still require surgical intervention.

Aneurysm↗
PubMedDate not supplied

Massive hepatic necrosis in the HELLP syndrome: CT correlation.

We present a patient with toxemia of pregnancy and the HELLP syndrome [hemolysis (H), elevated liver enzymes (EL), and a low platelet count (LP)] resulting in massive hepatic necrosis. Cross-sectional imaging, including sonography, computed tomography, and nuclear medicine, was instrumental in the diagnosis and differentiation from hepatic abnormalities of other pregnancy related entities especially acute fatty liver of pregnancy.

Adult↗