Terminal deoxynucleotidyltransferase containing megadalton complex from young rat thymus nuclei: identification and characterization

Nuclear matrix prepared from 2-3 week old rat thymuses contains tightly bound TdT activity which has been quantitatively solubilized with nonionic detergent and sonication. TdT is contained in a discrete complex with a sedimentation value of 23 S. The complex is retained on an anti-TdT antibody column and contains DNA ligase and 3'-5' exonuclease activities as well as DNA and several other proteins but is devoid of replicative DNA polymerases. Such a type of multienzyme complex is absent from the nuclear extracts of thymus prepared from older rats and also from liver and spleen extracts of young and old rats.     

Effect of prostaglandins on adenylate cyclase activities in membranes from liver and transplantable hepatomas.

The effects of prostaglandins on adenylate cyclase activity have been examined in membranes purified from normal rat liver and from a series of Morris hepatomas. Prostaglandin E1 gave the greatest stimulation (up to two-fold) in all membranes. However, prostaglandins A1, A2, and F2alpha, although stimulatory in liver and four tumor membranes, were inhibitory of adenylate cyclase activity in membranes from two of the fast-growing tumors. Arrhenius plots yielded broken line curves (at 20 degrees C) for the basal activity of all enzymes. Addition of various prostaglandins caused shifts in the broken line curves and/or produced nonbroken (straight) line curves for the liver and many of the hepatoma adenylate cyclases.     

Extreme ultraviolet radiation-sensitivity of respiratory adaptation in Saccharomyces cerevisiae cells during transition.

The respiratory adaptation process in both wild-type and UV-sensitive strains of $\text{Saccharomyces}\text{cerevisiae}$ was sensitive to small doses of UV-radiation (10 and 0.7 J/m², respectively). These doses of irradiation were ineffective in arresting induced synthesis of acid phosphatase and catalase. Exposure of the irradiated cells to visible light (370 – 800 nm) could completely restitute the impaired respiratory adaptation process. UV irradiation at these doses affected DNA and RNA synthesis in maturing mitochondria in both the yeast strains. The UV-induced block could however be eliminated by exposure of the cells to visible light. These results suggest that the lesion in the UV-induced block in the respiratory adaptation may be in the DNA of promitochondria.     

Mapping of retardance,diattenuation and polarizance vector on Poincare sphere for diagnosis and classification of cervical precancer

The mapping of diattenuation, polarizance and retardance vector (normalized Stokes vector) on Poincare sphere, evaluated from Mueller matrix of optically anisotropic stromal region of cervical tissues, is presented for cervical precancer detection and its staging. This reveals that the changes in the polarization states shown by these normalized Stokes vectors corresponds to the degradation of linearly arranged collagen fibers, breakage of the collagen cross links in the stromal region and change in the density of scattering sites when cervical cancer evolves. The distinct nature of real and imaginary parts of the refractive index for linear, linear‐45 and circular polarization from the optically anisotropic stromal region underscore the various polarization structures of the connective tissue region which get modified during the pathological changes. It has been found that versatility of these vectors for normal and precancerous cervical tissue of various grades may be utilized as a key distinction for qualitative staging of cervical precancer tissue. Quantitative classification of precancerous stages of cervical precancer has been determined with 95%–100% sensitivity and 93%–100% specificity through the evaluation of linear and circular diattenuation, linear polarizance and linear birefringence from the components of the respective vectors.     

Fc gamma receptor polymorphisms in systemic lupus erythematosus and their correlation with the clinical severity of the disease

Receptors for the Fc domains of IgG (Fc γ R) play a critical role in linking humoral and cellular immune responses. The various Fc γ R genes may contribute to differences in infectious and immune related diseases in various ethnic populations. Polymorphisms of Fc γ R mainly Fc γ R IIA, IIB, IIIA, IIIB have been identified as genetic factors influencing susceptibility to disease or disease course of a prototype autoimmune disease like Systemic Lupus Erythematosus (SLE). Activated and inhibitory Fc γ Rs seem to play an important role in the pathogenesis of SLE, in initiation of autoimmunity, the subsequent development of inflammatory lesions and finally immune clearance mechanisms. This review focuses on the role of Fc γ R polymorphism and their association with clinical manifestations and initiation of autoantibody production, inflammatory handling of immune complexes and disease development in SLE patients.     

Bacterial involvement in ulcerative condition of air-breathing fish from India

Four types of bacteria, two fluorescent pseudomonads, one aeromonad ( Aeromonas hydrophila anaerogens ) and one coccus ( Micrococcus variant ) were isolated from skin lesions of airbreathing fishes. The bacterial culture in mixed condition induced severe ulcers in healthy Anabas testudineus . Pure cultures of each of two pseudomonads and an aeromonad separated from the mixture induced superficial ulcer formation.     

Influence of cellular differentiation on ultraviolet induced DNA damage and its repair mechanisms in B. cereus

Susceptibility to UV irradiation of B. cereus BIS-59 spores undergoing germination at various stages-dormant spores to vegetative cell stage and their ability to recover from radiation damage were studied. For a given dose of radiation, the number of spore photoproducts (SPP) formed in the DNA of dormant spores was about 5-times greater than that of thymine dimers (TT) formed in the DNA of vegetative cells. At intermediate stages of the germination cycle, there was a rapid decline in the UV radiation-induced SPP formed in DNA with a concomitant increase in the UV radiation-induced TT formed in DNA. Bacterial spores undergoing germination (up to 3 hr) in the low nutrient medium (0.3% yeast extract) displayed much higher resistance to UV radiation than those germinating in the rich nutrient medium, even though there was no discernible difference under the two incubation conditions in respect of the extent of germination and the time at which the outgrowth stage appeared (3 hr). This was due to the formation TT in the DNA of spores germinating in the low nutrient as compared to that of spores germinating in the rich-nutrient medium. In UV-irradiated dormant spores, SPP formed in the spore DNA did not disappear even after prolonged incubation in the non-germinating medium. However, when the UV-irradiated dormant spores were germinated in low or rich nutrient medium, a significant proportion of SPP in DNA was eliminated. The dormant spores incubated in either of the germinating media for 15 min and then UV-irradiated were capable of eliminating SPP (presumably by monomerization) even by incubation in a non-germinating medium and in the complete absence of protein synthesis (buffer holding recovery), thereby implying that spore-repair enzymes were activated in response to initial's germination. The acquisition of photo-reactivation ability appeared in spores subjected to germination only in the rich-nutrient medium at the outgrowth stage and required de novo synthesis of the required enzymes.