Identification of a deoxyribonuclease activity in the nuclei of the cervical carcinoma HeLa

A deoxyribonuclease activity has been identified in the nuclei of the human cervical carcinoma HeLa. This activity has the novel property of existing as a single strand specific endo- and exodeoxyribonuclease activity. These activities are ionic strength sensitive, with retardation of activity occurring at 50 mM NaCl and above, with the Mn++ ion preferred over the Mg++ ion as activating cation. This activity extensively damages DNA via its single strand nicking and gaping activity. The method used to solubilize this activity as well as the enzyme's characteristics are discussed.     

Antioxidative activity of the blue pigment formed in a D-xylose-glycine reaction system

A blue compound was prepared from 1 M D-xylose and 0.1 M glycine, and designated Blue-M1, an intermediate color product of melanoidins. As melanoidins are well known to have antioxidative activity as well as high scavenging activity against active oxygen species, the antioxidative activity of Blue-M1 against the peroxidation of linoleic acid was investigated, in addition to the scavenging activity of Blue-M1 toward hydroxyl and DPPH radicals. Blue-M1 suppressed the peroxidation of linoleic acid as effectively as melanoidins did. The scavenging activity of Blue-M1 toward hydroxyl and DPPH radicals was also as strong as that of melanoidins. Blue-M1 showed higher activity with increasing concentration. The pyrrolopyrrole ring and a methine bridge between two pyrrolopyrrole rings in Blue-M1 could be related to the ability for radical scavenging activity, but not four carboxyl groups.     

Prehension in infant capuchins (Cebus apella) from six weeks to twenty-four weeks: video analysis of form and symmetry

We analyzed the spontaneous prehensile activity of two infants living with their mothers in social groups, using videotapes taken once weekly from weeks 5 to 24. Prehensile activities were laterally symmetric. Unimanual activity predominated, although bimanual activity appeared at the same ages as unimanual activity. In most bimanual activity the two hands performed the same action, but complementary actions occurred from the onset of bimanual activity. Extrusion of the tongue towards objects out of reach was observed occasionally, as was precision grasping. Early prehension in capuchins is organized, as in human infants, in a matrix of exploratory activity integrated with vision and oral exploration. Capuchins present a useful model system for the study of manipulative development.     

Daily activity profiles over the lifespan of female medflies as biomarkers of aging and longevity

The relationship between the early-age activity of Mediterranean fruit flies (medflies) or other fruit flies and their lifespan has not been much studied, in contrast to the connections between lifespan and diet, sexual signaling, and reproduction. The objective of this study is to assess intra-day and day-to-day activity profiles of female Mediterranean fruit flies and their role as biomarker of longevity as well as to explore the relationships between these activity profiles, diet, and age-at-death throughout the lifespan. We use advanced statistical methods from functional data analysis (FDA). Three distinct patterns of activity variations in early-age activity profiles can be distinguished. A low-caloric diet is associated with a delayed activity peak, while a high-caloric diet is linked with an earlier activity peak. We find that age-at-death of individual medflies is connected to their activity profiles in early life. An increased risk of mortality is associated with increased activity in early age, as well as with a higher contrast between daytime and nighttime activity. Conversely, medflies are more likely to have a longer lifespan when they are fed a medium-caloric diet and when their daily activity is more evenly distributed across the early-age span and between daytime and nighttime. The before-death activity profile of medflies displays two characteristic before-death patterns, where one pattern is characterized by slowly declining daily activity and the other by a sudden decline in activity that is followed by death.     

Antiviral and antiproliferative activity of human interferons and their induction of 2',5'-oligoadenylate synthetase

Native preparations of alpha, beta and gamma-interferons as well as recombinant beta-interferon and purified leukocyte alpha-interferon and purified leukocyte alpha-interferon exert antiviral and antiproliferative activity in CaOv cells. Native interferon preparations were shown to be more antiproliferative than purified interferons per unit of antiviral activity (with EMC as well as with less susceptible VSV used as test viruses). It was shown that level of 2'5' oligoadenylatesynthetase activity induction in general correlates with antiproliferative and pronounced antiviral activity of interferons, besides that, the earlier (by 11 hours) induction of the enzyme activity by beta-interferon correlates with more rapid expression of antiproliferative effects by this interferon in comparison with that of alpha-interferon, the latter inducing the peak of enzyme activity by 24 hours.     

Induction of maleate hydratase in Pseudomonas pseudoalcaligenes

Maleate hydratase (malease, EC 4.2.1.31) activity in P. pseudoalcaligenes is induced when grown on3-hydroxybenzoate. The specific malease activity was constant during the logarithmic phase in a batch culture containing 3-hydroxybenzoate as the carbon source, when 3-hydroxybenzoate-grown cells were used as inoculum. When yeast extract-grown cells were used as inoculum, the specific malease activity was correlated with growth. In both instances the specific malease activity dropped rapidly as soon as growth ceased. Maleate did not serve as a growth substrate for this microorganism, but a mutant able to grow on maleate was selected. The specific malease activity of maleate-grown cells of this mutant was not higher than the basal level of induction of malease activity.     

Enzymic hydrolysis of myelin basic protein and other proteins in central nervous system and lymphoid tissues from normal and demyelinating rats.

Proteolytic activity of central-nervous-system tissue of the normal rat was examined over the pH range 2-9 with casein, haemoglobin and myelin basic protein as substrates. With casein as a substrate, brain and spinal cord homogenates showed very similar activity profiles with increasing pH, with the main peaks of proteolytic activity at pH 3-4 and 5-6. When haemoglobin was used, one broad main peak of activity from pH 3 to 5 was demonstrated. There was no optimum pH, however, for proteolytic activity with myelin basic protein as a substrate, and considerable hydrolysis were observed from pH 3.5 up to pH8. Proteolytic activity at the various pH values was compared by using homogenates of spinal cords from rats with acute experimental allergic encephalomyelitis and those from rats injected with Freund's adjuvant alone. The profiles of activity were similar with peaks at pH 3.5 and 5.5 with casein as a substrate, but the specific activity was significantly higher at most pH values in the spinal-cord homogenates from rats with experimental allergic encephalomyelitis. Similarly the spinal-cord homogenates from these latter rats contained much more proteolytic activity toward myelin basic protein throughout the pH range than was present in the control spinal cords. Homogenates from lymph nodes of rats with experimental allergic encephalomyelitis and from those of the controls contained two to three times as much proteolytic activity as that of the central-nervous-system tissue and had a different proteolytic activity profile form that of the central-nervous system, with higher activity at the neutral than at acid pH. The results are discussed with regard to the probability that inflammatory cells such as lymphocytes may be the cause of the increased proteolytic activity in the central nervous system of animals with experimental allergic encephalomyelitis, and that enzymes from these cells possess the capability of digesting myelin basic protein.     

暗培养对黄瓜子叶节再生频率及其相关酶活性和可溶性蛋白含量的影响

以黄瓜品种新泰密刺子叶节为材料,观测了暗培养1~5 d黄瓜子叶节植株再生频率及其诱导过程中POD、SOD活性和可溶性蛋白含量的变化,以探究暗培养条件下黄瓜子叶节POD、SOD活性、可溶性蛋白含量与再生频率间的关系.结果表明,暗培养不仅可以使黄瓜子叶节POD活性持续增长,还有助于其活性保持在较高水平,D4处理在培养的第6天POD值高达243 U?g-1FW,对应的再生频率为87.20%,而对照的最高峰值仅为187.7 U?g-1FW,再生频率只有36.60%;POD的变化体现了各处理生理状态的差异,且各处理暗培养结束时的POD活性水平和POD峰值分别与植株再生频率之间存在显著正相关性,相关系数分别达到了0.921和0.839;而SOD活性水平与再生频率间无显著相关性;可溶性蛋白含量虽然可以体现子叶节生理状态的变化,但无法反映各暗处理对再生频率的影响差别.可见,暗培养有助于提高诱导过程中黄瓜子叶节POD活性的增速,使其活性保持在较高水平,且以POD活性为指标可以反映暗培养处理的有效性.     

Flavonols from Heterotheca inuloides: tyrosinase inhibitory activity and structural criteria

Tyrosinase inhibitory activity of flavonols, galangin, kaempferol and quercetin, was found to come from their ability to chelate copper in the enzyme. In contrast, the corresponding flavones, chrysin. apigenin and luteolin, did not chelate copper in the enzyme. The chelation mechanism seems to be specific to flavonols as long as the 3-hydroxyl group is free. Interestingly, flavonols affect the enzyme activity in different ways. For example, quercetin behaves as a cofactor and does not inhibit monophenolase activity. On the other hand, galangin inhibits monophenolase activity and does not act as a cofactor. Kaempferol neither acts as a cofactor nor inhibits monophenolase activity. However, these three flavonols are common to inhibit diphenolase activity by chelating copper in the enzyme.     

Peroxidase isoenzymes in Linum

Summary Isoenzymes of peroxidase were separated on acrylamide gels in 2 genotypes of Linum usitatissimum L. and their F ₁, F ₂ and first backcross progeny. Active extracts were obtained from homogenates of main stem tissue; activity was measured both before and after electrophoretic separation. The relationship of isoenzyme activity to gross (prior to electrophoretic separation) activity was investigated, as well as the relative behaviour of isoenzyme activity in the various genotypes and generations. Gross activity was correlated with isoenzyme activity; there was also evidence of maternal as well as genetic effects on isoenzyme activity.     

Enzyme activity in organic solvent as a function of water activity determined by membrane inlet mass spectrometry

Summary Membrane inlet mass spectrometry (MIMS) is introduced as a method for measuring water activity in nonpolar solvents, aqueous solutions and gas phase. The determination of the rate of hydrolysis of diphenyl carbonate by porcine liver esterase as a function of water activity in diisopropyl ether is presented as an example. A linear relationship is found between the enzyme activity and the water activity.     

淮河淮南段与巢湖水质污染对鲫鱼（Carassius auratus）的毒性效应

研究了枯水期淮河淮南段及巢湖西半湖水质污染对鲫鱼的毒性效应。从淮河淮南段与巢湖采集鱼类样本,并以未受人为污染的安丰塘鱼类为对照,分析了鲫鱼肝脏丙二醛（Malondialdehyde,MDA）含量、超氧化物歧化酶（Superoxide dismutase,SOD）活性、谷胱甘肽硫转移酶（Glutathione S-transferase,GST）活性、7-乙氧基异吩恶唑-O-脱乙基酶（7-ethoxyresorufin-O-deethylase,EROD）活性及DNA单链损伤情况,结果表明,淮河淮南段鲫鱼肝脏MDA含量、SOD活性、GST活性、EROD活性均高于对照组,分别是对照组的2.88、1.48、2.03和3.93倍;巢湖鲫鱼肝脏MDA含量、SOD活性、EROD活性均高于对照组,分别是对照组的2.28、1.85和2.74倍。肝细胞DNA单链断裂的测定显示淮河淮南段与巢湖的水质污染均对鲫鱼有遗传毒性。     

Extraembryonic motor activity during embryogenesis of higher vertebrates

Rhythmic motor activity of the extra-embryo structures as well as the embryo motor activity play a major part in normal development of higher vertebrates. When comparing birds and mammals, a trend towards complication of the motor activity regulation is observed. Reptiles as a class of the vertebrates have not been studied enough in this respect. Apart from the regular changes of extra-embryonic rhythmic motor activity, there are some changes in this activity depending on alterations of environmental factors (temperature, gas composition of air, etc.). The extra-embryonic rhythmic motor activity seems to take part in adaptation of the embryo to changing environmental conditions thus maintaining homeostasis of developing embryo.     

Intralysosomal hydrolysis of glycyl-L-phenylalanine 2-naphthylamide.

Glycyl-L-phenylalanine 2-naphthylamide (Gly-L-Phe-2-NNap), a cathepsin C substrate, induces an increase of the free and unsedimentable activities of this enzyme when incubated with a total mitochondrial fraction of rat liver. 1 mM-ZnSO4 considerably inhibits the cathepsin C total activity, measured with Gly-L-Phe-2-NNap as the substrate, in the presence of Triton X-100. The inhibition is markedly less pronounced when the free activity is determined; a high activity remains that depends on the integrity of the lysosomes; it decreases as the free activity of N-acetylglucosaminidase increases when lysosomes are subjected to treatments able to disrupt their membrane. Cathepsin C activity is reduced when thioethylamine hydrochloride is omitted from the incubation medium. Under these conditions at 37 degrees C, the free activity equals the total activity, although the lysosomes are intact, as indicated by the low free activity of N-acetylglucosaminidase. 1 mM-ZnSO4 strikingly inhibits the total activity, whereas more than 80% of the free activity remains. These observations are presented as evidence that Gly-L-Phe-2-NNap can possibly cause a disruption of the lysosomes as a result of its hydrolysis inside these organelles. In the presence of ZnSO4, intralysosomal hydrolysis becomes apparent, owing to a preferential inhibition by Zn2+ of extralysosomal hydrolysis; in the absence of thioethylamine hydrochloride, it is measurable because the disruption of lysosomes by Gly-L-Phe-2-NNap is delayed as a result of a slow-down of the reaction. The usefulness of Gly-L-Phe-2-NNap and related dipeptidyl naphthylamides in lysosomal-membrane-permeability studies is emphasized.     

Cardiac Autonomic Activity During Human Sleep: Analysis of Sleep Stages and Sleep Cycles

In this study characteristics of cardiac functioning were investigated in nine subjects during their nocturnal sleep. The pre-ejection period and the high frequency component of heart rate variability were used as indices of cardiac sympathetic and parasympathetic activity of the autonomic nervous system respectively. Heart rate and the autonomic indices were assessed across physiological determined sleep stages and consecutive temporal sleep cycles. Repeated measures ANOVA analyses indicated a significant pattern of heart rate as a function of sleep stages, which was mirrored by parasympathetic activity. Further, a significant decrease of heart rate as a function of sleep cycles was mirrored by an increase of sympathetic activity. Moreover, non-REM/REM differences revealed a dominant role of parasympathetic activity during sleep stages as well as sleep cycles. These findings demonstrate that sympathetic activity is influenced by time asleep, whereas parasympathetic activity is influenced by the depth of sleep.     

Change in the activity of specific and nonspecific immunity mechanisms in vitamin B1 deficiency]

The effect of thiamin deficiency on the immune response and activity of some mechanisms of natural immunity was studied in experimental mature rats. Thiamin deficiency was simulated by a single injection of hydroxythiamin (thiamin antagonists). Hydroxythiamin markedly decreased the complement activity, phagocytic activity of peripheral blood leucocytes, serum bactericidal activity as well as antibody production in response to sheep red blood cells. On the contrary, lysozyme activity increased. Vitamin B1 deficiency reduced 14C-leucine incorporation activity in the liver proteins.     

Insulin increases membrane and cytosolic protein kinase C activity in BC3H-1 myocytes

Insulin treatment stimulated the activity of the Ca2+- and phospholipid-dependent protein kinase (protein kinase C) in both cytosolic and membrane fractions of BC3H-1 myocytes. Within 60 s of insulin treatment, membrane protein kinase C activity increased 2-fold, diminished toward control levels transiently, and then increased 2-fold again after 15 min. Cytosolic protein kinase C activity increased more gradually and steadily up to 80% over a 20-min period. Increases in protein kinase C activity were dose-dependent and were not simply a result of translocation of cytosolic enzyme (although this may have occurred), as total activity was also increased. The increase in protein kinase C activity was not inhibited by cycloheximide (which also increased protein kinase C activity and 2-deoxyglucose transport) and was still evident following anion exchange chromatography. The insulin effect was decidedly different from those of 12-O-tetradecanoylphorbol-13-acetate and phenylephrine using histone III-S as substrate. Phenylephrine decreased cytosolic protein kinase C activity while increasing membrane activity; 12-O-tetradecanoylphorbol-13-acetate only decreased cytosolic protein kinase C activity. The early insulin-induced increases in membrane protein kinase C activity may be related to increased diacylglycerol generation from de novo phosphatidic acid synthesis, as there were rapid increases in [3H]glycerol incorporation into diacylglycerol, and transient increases in phospholipid hydrolysis, as there were transient rapid increases in [3H]diacylglycerol in cells prelabeled with [3H]arachidonate. Later, sustained increases in membrane and cytosolic protein kinase C activity may reflect the continuous activation of de novo phospholipid synthesis, as there were associated increases in [3H]glycerol incorporation into diacylglycerol at later, as well as very early time points.     

Relationship between estrogen receptor-binding and estrogenic activities of environmental estrogens and suppression by flavonoids

In this study, we investigated the estrogenic activity of environmental estrogens by a competition binding assay using a human recombinant estrogens receptor (hERbeta) and by a proliferation assay using MCF-7 cells and a sulforhodamine-B assay. In the binding assay, pharmaceuticals had a stronger binding activity to hERbeta than that of some phytoestrogens (coumestrol, daidzein, genistein, luteolin, chrysin, flavone, and naringenin) or industrial chemicals, but phytoestrogens such as coumestrol had a binding activity as strong as pharmaceuticals such as 17alpha-ethynylestradiol (EE), tamoxifen (Tam), and mestranol. In the proliferation assay, pharmaceuticals such as diethylstilbestrol, EE, Tam, and clomiphene, and industrial chemicals such as 4-nonylphenol, bisphenol A, and 4-dihydroxybiphenyl had a proliferation-stimulating activity as strong as 17beta-estradiol (ES). In addition, we found that phytoestrogens such as coumestrol, daidzein, luteolin, and quercetin exerted a proliferation stimulating activity as strong as ES. Furthermore, we examined the suppression of proliferation-stimulating activity, induced by environmental estrogen, by flavonoids, such as daidzein, genistein, quercetin, and luteolin, and found that these flavonoids suppressed the induction of the proliferation-stimulating activity of environmental estrogens. The suppressive effect of flavonoids suggests that these compounds have anti-estrogenic and anti-cancer activities.     

Bacterial endotoxin selectively prevents the expression of scavenger-receptor activity on human monocyte-macrophages

Concentrations of bacterial lipopolysaccharide (LPS) as low as 1 ng/ml suppressed the activity of the scavenger receptor on cultured human monocyte-macrophages. In contrast, concentrations of LPS as high as 100 ng/ml had no effect on the activity of the low density lipoprotein (LDL) receptor. LPS and purified forms of the lipid A moiety of LPS were effective in suppressing scavenger receptor activity. However, acid hydrolysis of the labile phosphate group of the native diphosphorylated lipid A to form monophosphoryl lipid A rendered the molecule ineffective in suppressing scavenger receptor activity. LPS at a concentration of 100 ng/ml had no effect on the secretion of apolipoprotein E, phagocytic activity, tumoricidal activity, or the protein content of monocyte-macrophages. We conclude that the active component of LPS that mediates suppression of scavenger receptor activity is diphosphoryl lipid A.