The effect of sugars on inverse relation between the growth and chlorophy11 synthesis in tobacco tissue

Cytokinin-dependent and cytokinin-autonomous strains of tobacco callus tissue (Nicotiana tabacum L. cv. ‘Wisconsin 38’) were grown on media containing sucrose, glucose and fructose, respectively. The tissues were kept 14 days in darkness and then transferred for 9 days to continuous light after which time the fresh weight and chlorophyll content were estimated. The highest chlorophyll concentration was recorded at sugar levels which were either suboptimal (sucrose in the case of cytokinin-dependent strain) or supraoptimal (all other sugars for both strains and sucrose for the cytokinin-autonomous strain) for tissue growth. The chlorophyll concentration was increased when the tissue was cultured on media containing glucose or fructose,i.e. sugars whioh did not support the growth as well as sucrose. Chlorophyll synthesis in the cytokinin-autonomous strain is significantly lower than in the cytokinin-dependent strain. This difference was independent of either sugar source or concentration. These results support the observed inverse relationship between tissue growth and plastid development and the limited metabolic activity of plastids in cytokinin-autonomous tissues.     

In vitro and in vivo studies on the mechanism of experimental autoimmune thyroiditis in guinea pigs

Thyroid explants of inbred strain 13 guinea pigs were grown in a semisynthetic medium containing 0.3 IU of thyroid-stimulating hormone. The monolayer retained the capacity in vitro to form thyroglobulin. Sensitized lymphocytes from animals with autoimmune thyroiditis could specifically lyse these thyroid target cells in vitro in the presence of an appropriate amount of specific antigen. This cytotoxicity was not observed in thyroid epithelial cells which had been incubated (a) with normal lymphocytes or (b) with purified macrophages either from normal animals or from animals with autoimmune thyroiditis. When thyroid cells were incubated with hyperimmune antithyroglobulin serum, cytolysis did not occur, whether or not complement was added. The cytopathic effect of sensitized lymphocytes was further demonstrated to be caused by a soluble cellular product, termed thyroid cytotoxic factor, or TCF, which was released from sensitized lymphocytes under the stimulation of specific antigen, thyroglobulin, and could exert a cytotoxic effect directly on the target cells. Direct cell-to-cell contact was not required in this type of cell-mediated cytolysis.     

Plasma membrane localization of alkaline phosphatase in HeLa cells.

The localization of alkaline phosphatase in HeLa cells was examined by electron microscopic histochemistry and subcellular fractionation techniques. Two monophenotypic sublines of HeLa cells which respectively produced Regan and non-Regan isoenzymes of alkaline phosphatase were used for this study. The electron microscopic histochemical results showed that in both sublines the major location of alkaline phosphatase is in the plasma membrane. The enzyme reaction was occasionally observed in some of the dense body lysosomes. This result was supported by data obtained from a subcellular fractionation study which showed that the microsomal fraction rich in plasma membrane fragments had the highest activity of alkaline phosphatase. The distribution of this enzyme among the subcellular fractions closely paralleled that of the 5'-nucleotidase, a plasma membrane marker enzyme. Characterization of the alkaline phosphatase present in each subcellular fraction showed identical enzyme properties, which suggests that a single isoenzyme exists among fractions obtained from each cell line. The results, therefore, confirm the reports suggesting that plasma membrane is the major site of alkaline phosphatase localization in HeLa cells. The absence of any enzyme reaction in the perimitochondrial space in these cultured tumor cells also indicates that the mitochondrial localization of the Regan isoenzyme reported in ovarian cancer may not be a common phenomenon in Regan-producing cancer cells.     

The carbamate reaction of glycylglycine, plasma, and tissue extracts evaluated by a pH stopped flow apparatus.

We have used a stopped flow rapid reaction pH apparatus to investigate the carbamate equilibrium in glycylglycine solutions and in three biological tissues, human plasma, sheep muscle, and sheep brain, as well as to investigate the kinetics of carbamate formation in glyclyglycine solution and in human plasma. The rapid reaction apparatus was equipped with a pH sensitive glass electrode in order to follow the time course of pH from 0.005 to 100 s after rapid mixing of a solution of amine or protein and CO2. Two phases of the pH curve were observed: a fast phase representing carbamate formation, and a slow phase due to the hydration of CO2 which was uncatalyzed since a carbonic anhydrase inhibitor was added to the biological solutions. From the time course of pH change during the fast phase K2, the R-NH2 ionization constant, and Kc, the carbamate equilibrium constant as well as the velocity constant for the formation of carbamate, ka could be calculated from data at different pH and pCO2. The carbamate formed in glycylglycine solutions over a wide range of pH and pCO2 was found consistent with the theory of carbamate formation and with published data. At ionic strength 0.16 and 37 degrees pK is 7.67. pKc 4.58. The heat of the carbamate reaction (deltaH) was calculated to be -3.2 kcal/mol between 20 degrees and 37 degrees. Kt of glycylglycine depends quantitatively on ionic strength as predicted by the Debye-Huckel theory. With ionic strength 0.16 ku was found to be 2,500 M1 S1 at 37 degrees. The activation energy of carbamate formation is 6.7 kcal/mol. Carbamate measurements in human plasma at pCO2 from 38 to 359 Torr. pH from 6.9 to 8.3, temperature 37 degrees, and ionic strength 0.15 provided evidence that two kinds of amino groups participate in carbamate formation. From the equilibrium constants computed for the two species they could be identified as alpha- and epsilon-amino groups. On the basis of a protein molecular weight of 69.000. 0.6 alpha-amino groups/molecule with pKz=7.0 and pKc=4.2, and 5.9 epsilon-amino groups/molecule with pKz=9.0 and pKc=4.3 contribute to carbamate formation. The velocity constant ka was estimated to be 4,950 M1 S1 for the alpha-amino groups and 13,800 M1 S1 for the epsilon-amino groups. Under physiological conditions (pCO2=40 Torr. pH=7.4). The concentration of carbamate in plasma is 0.6 mM and the half-time of carbamate formation is 0.05 s. In extracts prepared from sheep brain at 37 degrees pH=7 and pCO2=35 Torr. the carbamate formation was estimated to be 0.8 mM. With pCO2=70 Torr and the same pH and temperature the carbamate concentration in muscle approximates 0.3 mM and increases to 7 mM as pH rises to 8. It is concluded that, as in plasma, a considerable number of epsilon-amino groups appear to be available for carbamate formation in these tissues.     

Chromosome analysis on 930 consecutive newborn children using quinacrine fluorescent banding technique

Summary Chromosome analysing using quinacrine fluorescence was performed on 930 consecutive newborn infants. The total incidence of major chromosome aberrations including numerical changes of the sex chromosomes, and structural changes of autosomes, was 0.54%. Incidences of XYY (0.4%) and XXY (0.2%) were relatively higher as compared to other studies. About 0.75% of the newborn infants were found to have a variable bright fluorescent band located on the proximal area of the short arm (p11) rather than on the proximal long arm (q11) of chromosome No. 3. Attempts were also made to record the variable fluorescent regions on 7 autosomes and the Y chromosome.     

Quinacrine fluorescence and Q-banding patterns of human chromosomes. I. Effects of varying factors.

Various factors involved in the production of "Q-bands" have been studied. It was found that a Zeiss standard WL fluorescent microscope required a shorter exposure time for photography as compared to a Zeiss photomicroscope. The minimal exposure time was obtained when the standard WL microscope was equipped with a UV light source containing a DC powered mercury burner and a concave mirror. Further, the pH and type of water used in the staining, washing and mounting of the slide were also important factors in producing clear and well differentiated "Q-bands". It also appears that the factors involved in the production of "Q-bands" effect the enhancement or quenching of fluorescence by poly d(A-T)-poly d(A-T) and salmon sperm DNA or poly dG-poly dC respectively. This preliminary report also suggests that DNA or polynucleotides with a specific base sequence may play an important role in Q-banding patterns on chromosomes.     

Removal of Enteroviruses from Sewage by Bench-Scale Rotary-Tube Trickling Filters

The efficacy of a rotary-tube type of trickling filter for removing coxsackievirus A9, poliovirus 1, and echovirus 12 suspended in raw settled sewage was investigated. At filtration rates equivalent to about 10 MGD (million gallons per day)/acre (ca. 3,785 m3/day per acre), the filters removed 95% of the poliovirus, 83% of echovirus 12, and 94% of coxsackievirus A9. Coliform, fecal streptococci, biochemical oxygen demand, and chemical oxygen demand removals were remarkably similar, averaging 94, 92, 93, and 95%, respectively. At filtration rates equivalent to about 23 MGD/acre, 59% of the poliovirus, 63% of the echovirus 23, and 81% of the coxsackievirus A9 were removed. Coliform, fecal streptococci, biochemical oxygen demand, and chemical oxygen demand removals at this filtration rate were 68, 75, 72, and 56%, respectively. Viruses were assumed to be adsorbed to the biological slime growing in the filters, but attempts to disassociate the viruses from the slime were unsuccessful, indicating that the slime-virus complex is very stable or that the viruses were somehow inactivated. The data indicate that coliform and fecal streptococci reductions in this type sewage treatment process can be used as an index of virus reduction. Disinfection, however, must be used to ensure a virus-free final effluent.