bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal sitagliptin treatment attenuates offspring glucose metabolism and intestinal proinflammatory cytokines IL-6 and TNF-α expression in male rats
Authors: Zhang Qian , Xiao Xinhua , Zheng Jia , Li Ming , Yu Miao , Ping Fan , Wang Tong , Wang Xiaojing
Published: November 2020

Increasing evidence shows that maternal overnutrition may increase the risk of diabetes in offspring. We hypothesized that maternal sitagliptin intervention may improve glucose intolerance through gut targeting. Female Sprague-Dawley (SD) rats were fed a normal diet (ND) or a high-fat diet (HFD) for 4 weeks before mating. ND pregnant rats were divided into two subgroups: ND group (ND alone) and the ND-sitagliptin group (ND combined with 10 mg/kg/day sitagliptin treatment). HFD pregnant rats were randomized to one of two groups: HFD group (HFD alone) and the HFD-sitagliptin group (HFD combined with 10 mg/kg/day sitagliptin treatment) during pregnancy and lactation. Glucose metabolism was assessed in offspring at weaning. Intestinal gene expression levels were investigated. Maternal sitagliptin intervention moderated glucose intolerance and insulin resistance in male pups. Moreover, maternal sitagliptin treatment inhibited offspring disordered intestinal expression of proinflammatory markers, including interleukin-6 (Il6), ll1b, and tumor necrosis factor (Tnf), at weaning and reduced intestinal IL-6, TNF-α expression by immunohistochemical staining and serum IL-6, TNF-α levels. However, maternal sitagliptin intervention did not affect offspring serum anti-inflammatory cytokine IL-10 level. Our results are the first to show that maternal sitagliptin intervention moderated glucose metabolism in male offspring. It may be involved with moderating intestinal IL-6 and TNF-α expression in male rat offspring.
Deregulation of lysophosphatidic acid metabolism in oral cancer promotes cell migration via the up-regulation of COX-2
Authors: Abdul Rahman Mariati , Tan May Leng , Johnson Steven P. , Hollows Robert J. , Chai Wen Lin , Mansell Jason P. , Yap Lee Fah , Paterson Ian C.
Published: November 2020

Oral squamous cell carcinoma (OSCC) is the sixth most common cancer worldwide and accounts for 300,000 new cases yearly. The five-year survival rate is approximately 50% and the major challenges to improving patient prognosis include late presentation, treatment resistance, second primary tumours and the lack of targeted therapies. Therefore, there is a compelling need to develop novel therapeutic strategies. In this study, we have examined the effect of lysophosphatidic acid (LPA) on OSCC cell migration, invasion and response to radiation, and investigated the contribution of cyclooxygenase-2 (COX-2) in mediating the tumour promoting effects of LPA. Using the TCGA data set, we show that the expression of the lipid phosphate phosphatases (LPP), LPP1 and LPP3, was significantly down-regulated in OSCC tissues. There was no significant difference in the expression of the ENPP2 gene, which encodes for the enzyme autotaxin (ATX) that produces LPA, between OSCCs and control tissues but ENPP2 levels were elevated in a subgroup of OSCCs. To explore the phenotypic effects of LPA, we treated OSCC cell lines with LPA and showed that the lipid enhanced migration and invasion as well as suppressed the response of the cells to irradiation. We also show that LPA increased COX-2 mRNA and protein levels in OSCC cell lines and inhibition of COX-2 activity with the COX-2 inhibitor, NS398, attenuated LPA-induced OSCC cell migration. Collectively, our data show for the first time that COX-2 mediates some of the pro-tumorigenic effects of LPA in OSCC and identifies the ATX-LPP-LPA-COX-2 pathway as a potential therapeutic target for this disease.
The Proximate Analysis of Cakwe with Addition of Nilem Fish Protein Concentrate
Authors: Junianto . , Alifah Tahira , Rostini Iis , Pratama Rusky Intan
Published: November 2020

Nilem fish (Osteochilus hasselti) are native Indonesian fish that live in freshwaters, such as rivers and swamps. This research aims to obtain the composition of proximate cakwe with the addition of nilem fish protein concentrate. Proximate parameters observed were water content, protein content, fat content, and ash content using the Association of Official Analytical Chemists (AOAC) method. This research was conducted from March 2019 to January 2020 at the Laboratory of Fishery Product Processing, Faculty of Fisheries and Marine Sciences, Padjadjaran University and Laboratory of Chemistry Research, PPBS, Padjadjaran University. The method used is an experimental method with the treatment of 5% nilem fish protein concentrate. The proximate test results showed that cakwe with the addition of nilem fish protein concentrate contained 27.72% water content, 10.42% protein content, 5.36% fat content, and 4.38% ash content.
Statistical Analysis of Tensile Strength and Flexural Strength Data from Universal Testing Machine
Authors: Shamsuri Ahmad Adlie , Darus Siti Atiqa Al Zahra Mat
Published: November 2020

The tensile strength and flexural strength are the most important mechanical properties as they provide the value of maximum tensile stress and flexural stress. The objective of this study is to analyze statistically the tensile strength and flexural strength data obtained from a universal testing machine. The tests were conducted upon a thermoplastic, specifically high-density polyethylene (HDPE), which was in-house molded by using an injection-molding machine. Three different persons have performed the tensile and flexural tests. Three other laboratories have also been involved in these tests. The relative standard deviation (RSD) values were calculated to express the precision and repeatability of the tests. Later, the standard score (z-score) values were also calculated to aid the comparison of the data. Finally, the single-factor analysis of variance (ANOVA) was employed to investigate statistically significant differences between the means of the tensile strength and flexural strength data of each person and laboratory. From the calculation, the RSD values of all three persons and laboratories were lower than 5%, indicating that the data were consistent. The z-score values of all three persons were within the range from -2 to 2, suggesting that the data were close to average. However, the z-score value for one of three laboratories was not within the range, demonstrating that the data was unusual. The P-values of all three persons were higher than 0.05 (except for flexural strength), implying that the difference between the means of the data was not statistically significant. Nevertheless, the P-values of all three laboratories were lower than 0.05, indicating that the difference between the means of the data was statistically significant.
Distribution Pattern of Soil-transmitted Helminths and Common Practices Enhancing Transmission in Owena, Southwestern Nigeria
Authors: Awosolu Oluwaseun Bunmi , Adu Olubunmi , Olusi Titus Adeniyi
Published: November 2020

Geohelminth infection are a major public health problem worldwide particularly in Africa. This study was carried out to investigate the distribution pattern of soil-transmitted helminths and common practices enhancing transmission in Owena, Southwestern Nigeria. Two hundred (200) soil samples were obtained from five different locations in Owena community and examined for the presence and absence of geohelminths eggs and larvae using Modified Cobbs decanting and sieving method. Different activities and practices that could enhance parasite transmission in the environment were investigated through a well-designed questionnaire. The result revealed that out of the 200 soil samples, 61% were contaminated with at least one parasite. The parasites encountered include Ascaris lumbricoides, Trichiuris trichiura, hookworms and Strongyloides stercoralis. Hookworm have the highest contamination prevalence of 55.8%. Furthermore, the result showed that 167 (38.5%) of the respondents does not have appropriate means of waste disposal and as such 29 (14.5%) dispose their waste in the river and 165 (82.5%) dispose their waste materials in any available site such as bushes and backyards. In the same vein only         115 (57.5%) have toilet facilities while 82 (42.5%) does not have toilet facilities. With regard to the type of toilet used, 30 (15%) uses water closet toilet, 84 (42%) make use of pit toilet while 86 (43%) get rid of their faeces through any available mean including bushes and backyards. this result is an evidence that geohelminth is still prevalent and pose a significant health challenge to the residents of Owena community. Thus appropriate management strategy such as health education should be encouraged.
Physico-Chemical Properties of Four Selected Groundnut Varieties
Authors: Sravani M. , Boreddy Sreenivasula Reddy , Madhava M. , Kumari P. Lavanya
Published: November 2020

The physico-chemical properties of four popular groundnut (peanut) varieties namely Trombay-Akola Groundnut-24 (TAG-24), Kadiri-6 (K6), Kadiri-9 (K9), and Kadiri-Harithandra (KH) were determined by following the standard measurement methods. The average geometrical mean diameter (GMD) and sphericity values of peanut pods ranged from 14.91 mm (K9) to 16.61 mm (KH) and from 0.56 to 0.63, respectively. The 100 whole pods mass for four different peanut varieties are significantly different from each other. The bulk density of peanut pods ranged from 232.7 kg/m3 (K9) to 289.0 kg/m3 (K6) and these are significantly different from each other. The calculated porosity values for peanut pods varied from 37.89% (KH) to 47.32% (TAG-24). For the kernels, the highest GMD value of 10.57 mm was recorded for the KH variety and the lowest GMD value of 9.33 mm was found for the K6 variety. Sphericity values for peanut kernels ranged from 0.71 (K6) to 0.78 (K9). The average 100 kernels mass ranged from 46.23 g (TAG-24) to 56.34 g (for K9). The bulk density of kernels ranged from 583.4 kg/m3 (K9) to 611.9 kg/m3 (K6). However, the bulk density of peanut kernels is not significantly different for the varieties from each other. The true density values of peanut kernels ranged from1020.4 kg/m3 (K6) to 1052.0 kg/m3 (TAG-24). The porosity values for peanut kernels ranged from 40.06% (K6) to 43.64% (TAG-24) and they are not significantly different for the varieties from each other. Among all the varieties, KH variety had the lowest ash content of 2.18% and also the lowest protein content. The oil content of selected peanut varieties ranged from 45.36% (K9) to 48.22% (KH).The physical properties measured in this study are helpful to design and develop suitable pre and primary processing equipment. Proximate composition gives an idea to decide peanut’s suitability for manufacturing products such as peanut butter.
Augmenting in vitro Shoot Multiplication by Growth Regulators and Photoperiod in Vigna mungo L. (Hepper.)
Authors: Singh Soumya Sucharita , Pradhan Cinmaya , Swain Dhaneswar , Rout Gyana Ranjan
Published: November 2020

An efficient in vitro protocol was developed for the mass multiplication of Vigna mungo vars. PU30 and PU31, an important legume crop through apical meristems and cotyledonary nodal explants. Both apical meristems and cotyledonary nodal explants were cultured on Murashige and Skoog (MS, 1962) medium fortified with 0.5 – 1.50 mg/L 6- benzyl aminopurine (BA) or Kinetin and 3 % (w/v) sucrose. The rate of multiplication was higher when the cultures were incubated under continuous light (24h) than the 16h photoperiod. The average number of multiple shoots per culture was enhanced from 2.43 to 5.46 in the case of var. PU30 and 3.12 to 5.82 in the case of var.PU31 within 4 weeks of culture under 24h photoperiod. The multiplication rate was enhanced till 5th subculture declined thereafter. Rooting was readily achieved upon transferring the shoots to half-strength MS basal semisolid medium supplemented with 0.1– 1.0 mg/L indole-3-butyric acid (IBA) and 2% (w/v) sucrose after 2 weeks of culture.  The average number of roots per explants ranged from 3.12 to 5.76.  About 80% of regenerated plantlets were hardened in the greenhouse and successfully established in the soil. There is no morphological variation among the regenerated plantlets. This protocol can be used for genetic transformation study for crop improvement of black gram.
Prevalence of Anxiety and Depression during the Coronavirus Disease 2019 Pandemic in Riyadh, Saudi Arabia: A Web-Based Cross-Sectional Survey
Authors: Alhalafi Abdullah Hassan
Published: November 2020

Today, every continent in the world is affected by the novel coronavirus2019 (COVID-19). Saudi Arabia has also suffered from this highly contagious, socially disruptive, infectious disease. Our aim was to assess the anxiety and depression prevalence and identify the associated risk factors among the general population of Riyadh city, Saudi Arabia, during COVID-19 outbreak. This cross-sectional study was conducted using a web-based survey. A total of 651 participants were recruited who were ≥18 years old and lived in Riyadh city during the COVID-19 pandemic. We collected sociodemographic information of the participants and assessed their COVID-19-related knowledge assessment. We used the Arabic versions of the Generalized Anxiety Disorder-7 questionnaire and the Patient Health Questionnaire to assess the status of an individual’s anxiety and depression, respectively. We observed 28.7% and 25.5% prevalence of depression and anxiety among the general population, respectively. Females, younger people (age < 35 years), and unmarried persons showed a significantly higher prevalence of anxiety and depression. Binary logistic regression analysis also revealed that female gender, age younger than 35 years, having history of psychiatric diseases, and spending more than one hour per day on following COVID-19 news were associated with anxiety and depression. Retired participants were less likely to suffer from anxiety or depression during the pandemic. In this study, females, younger people (age < 35 years), and individuals with history of psychiatric patients were identified as vulnerable groups who need support during this crisis. We also recommend that the general public must limit their time of watching and following COVID-19-related news.
The hydroperoxide‐induced release of mitochondrial calcium occurs via a distinct pathway and leaves mitochondria intact
Authors: Baumhüter Susanne , Richter Christoph
Published: July 2002

The hydroperoxide‐induced net release of Ca2+ from rat liver mitochondria is stimulated by the Ca2+ uptake inhibitor ruthenium red. At moderate Ca2+ loads the release takes place with preservation of a high mitochondrial membrane potential. During and after Ca2+ release mitochondria remain intact. The hydroperoxide‐induced release of Ca2+ might therefore be a physiological relevance.
The effect of superoxide generation on the ability of mitochondria to take up and retain Ca2+
Authors: Harris E.J. , Booth R. , Cooper M.B.
Published: July 2002

When heart or liver mitochondria are exposed to superoxide radicals generated from xanthine + xanthine oxidase their ability to take up and to retain Ca2+ is impaired. The rate of oxidation of pyruvate + malate as substrates is diminished and the appearance of thiol groups when the mitochondria are supplied with these substrates is abolished. These inhibitory effects are offset if respiration is supported by succinate in presence of rotenone provided that a substrate (β‐hydroxybutyrate) is provided to maintain the reduction of NADH. The data agree with the thesis that a generation of thiol groups is essential to maintain membrane integrity and that the generation depends on provision of reduced NAD(P)H.
Lack of desensitization against α‐agonists and vasopressin in the liver
Authors: Kleineke Jochen , Söling Hans-Dieter
Published: July 2002

A heterologous and homologous desensitization of the glycogenolytic response against 3′,5′‐cAMP independent hormones in isolated hepatocytes has been reported [Biochem. J. (1981) 200, 509–514]. We re‐examined this phenomenon in isolated perfused rat livers, isolated hepatocytes during stationary incubation and in isolated perifused hepatocytes. The release of glucose and the activation of glycogen phosphorylase were followed in the presence of phenylephrine (10−5 M) or vasopressin (2.5 × 10−8 M). A desensitization against these hormones could not be observed in the presence of exogenous calcium (1.3 mM). When calcium‐free media were applied, the perfused liver became successively resistant toward the action of phenylephrine (or vasopressin), but regained sensitivity immediately after addition of 1.3 mM calcium to the medium. It is concluded that in isolated hepatocytes desensitization against hormones acting via mobilization of intracellular calcium is an artifact resulting from the experimental conditions.
Muscarinic stimulation of phospholipid turnover in dissociated avian salt gland cells
Authors: Fisher Stephen K. , Hootman Seth R. , Heacock Anne M. , Ernst Stephen A. , Agranoff Bernard W.
Published: July 2002

Addition of carbamylcholine to 32P‐prelabeled dissociated avian salt gland cells resulted in increased turnover of phosphatidic acid, phosphatidylinositol, phosphatidylinositol 4‐phosphate and phosphatidylinositol 4,5‐bisphosphate, which could be prevented by the inclusion of atropine. Carbamylcholine had no discernable effect on protein phosphorylation, measured either in the total preparation or in subcellular fractions. It is concluded that for the avian salt gland, no obligatory link is indicated between protein phosphorylation and either phospholipid turnover or salt secretion.
Analysis of brain metabolism changes induced by acute potassium cyanide intoxication by 31P NMR in vivo using chronically implanted surface coils
Authors: Decorps M. , Lebas J.F. , Leviel J.L. , Confort S. , Remy C. , Benabid A.L.
Published: July 2002

Chronic implantation of surface coils on the skull has been developed to record 31P NMR spectra of the brain in unanesthetized rats. Intraperitoneal sublethal potassium cyanide doses induce strong and reversible changes in high‐energy phosphate compounds in the brain, similar in part to those induced by ischemia. These effects are dose‐dependent as far as phosphocreatine, inorganic orthophosphates and pH are concerned; ATP does not seem to be altered by KCN doses ranging from 3 to 5 mg/kg but starts decreasing at a dose of 6 mg/kg. The fraction of Mg2+ complexed ATP which could be estimated as about 90% was not affected by KCN intoxication. For high doses (6 mg/kg) a new peak, appearing on the upfield side of the inorganic phosphate peak, may correspond to an acidic compartment, the significance of which is discussed.
Oocyte adenylyl cyclase contains Ni, yet the guanine nucleotide‐dependent inhibition by progesterone is not sensitive to pertussis toxin
Authors: Birnbaumer Lutz , Olate Juan , Allende Catherine C. , Allende Jorge E. , Sekura Ronald D.
Published: July 2002

The possible susceptibility to pertussis toxin of the guanine nucleotide‐dependent inhibition of oocyte adenylyl cyclase by progesterone was investigated. This action of progesterone is mediated by a membrane bound receptor as opposed to a receptor of cytosolic or nuclear localization. However, the inhibitory effect of progesterone was unaffected by pertussis toxin, even though the oocyte membrane Ni was fully ADP‐ribosylated with pertussis toxin, as revealed by lack of further [32P]ADP‐ribosylation on subsequent re‐incubation with pertussis toxin. These results indicate that the action of progesterone, in spite of being nucleotide‐dependent, is either not mediated by Ni, suggesting the existence of an additional nucleotide regulatory component, or if mediated by Ni, involves a mode of regulation of this coupling protein that is different from that by which all other inhibitory hormones act on adenylyl cyclase.
The role of lipids and 17‐kDa protein in enhancing the recovery of O2 evolution in cholate‐treated thylakoid membranes
Authors: Akabori Kozo , Imaoka Akiko , Toyoshima Yoshinori
Published: July 2002

The recovery of O2 evolution of cholate‐treated thylakoids induced by the simultaneous addition of the 17‐ and 23‐kDa proteins was enhanced by the further addition of thylakoid total lipids up to about 75% of the non‐depleted original broken thylakoids at the optimal concentration of the lipids, through reactivation of electron transfer between the sites of DPC donation and DCIP acceptance. Novel findings clarifing the cause of the discrepancies, with regard to the requirement for the 17‐kDa protein on the O2 evolution of thylakoid membranes, were also provided, i.e., when the assay of O2 evolution for the reconstituted systems was carried out at a low level of NaCl (e.g., 0.1 mM), besides the 23‐kDa protein, the 17‐kDa protein was also required for O2 evolution, however, at a higher level of NaCI (>5 mM) the 17‐kDa protein was not. The results suggest that the 17‐kDa protein takes the place of Cl− or acts as a constituent protecting C− in the Cl− activating sites against fluctuation of the Cl− level in the inner compartment of thylakoid membranes.
Insulin‐like growth factor I supports differentiation of cultured osteoblast‐like cells
Authors: Schmid C. , Steiner T. , Froesch E.R.
Published: July 2002

Rat calvaria cells grown in culture for one week had properties of osteoblasts: a high content in alkaline phosphatase and a marked cyclic AMP response to parathyroid hormone (PTH). In short‐term experiments, insulin‐like growth factor I (IGFI) stimulated the incorporation of (14C]glucose into glycogen. When IGF I was present in the medium during 6 days the cell number increased slightly and there was a substantial, disproportionate rise in alkaline phosphatase activity of the cultures. Thus, IGFI stimulates growth, and in addition, and in contrast to other growth factors, mainly enhances differentiation of osteoblasts.
Both insulin and epidermal growth factor stimulate fatty acid synthesis and increase phosphorylation of acetyl‐CoA carboxylase and ATP‐citrate lyase in isolated hepatocytes
Authors: Holland Ross , Hardie D.Grahame
Published: July 2002

Insulin and EGF cause identical stimulation(≅40%) of fatty acid synthesis in hepatocytes isolated from rats which have been starved and then refed a low‐fat diet. In both cases this stimulation is associated with increased phosphorylation of ATP‐citrate lyase and of a specific site on acetyl‐CoA carboxylase. However, the altered phosphorylation of acetyl‐CoA carboxylase is not associated with a change in kinetic parameters which is detectable in the purified enzyme. Whatever the mechanism involved, stimulation of fatty acid synthesis by growth factors may have a role in providing new phospholipid for growth of membranes.
Resolution of bovine brain calcineurin subunits: stimulatory effect of subunit B on subunit A phosphatase activity
Authors: Gupta Ramesh C. , Khandelwal Ramji L. , Sulakhe Prakash V.
Published: July 2002

Calcineurin was dissociated into subunits A and B by SDS and the dissociated subunits were separated by Sephadex G‐100 column chromatography in SDS. The phosphatase activity was associated with the A subunit and was detected only in the presence of MnCl2 of the various divalent cations tested. The Mn2+‐dependent phosphatase of A subunit was stimulated (4‐5‐fold) by calmodulin. The subunit B increased only modestly Mn2+ stimulated phosphatase activity of subunit A but markedly increased it when assay also contained calmodulin. These results support the view that subunit B plays an important role in Mn2+/calmodulin regulation of subunit A phosphatase activity. They also lend further support to our earlier postulate ([1984] FEBS Lett. 169, 251‐255) that Mn2+ is a powerful regulator of calcineurin phosphatase.
Single channel recordings obtained from basolateral membranes of isolated rabbit enterocytes
Authors: Sepúlveda F.V. , Mason W.T.
Published: July 2002

Epithelial cells isolated by hyaluronidase incubation from rabbit small intestine were used to explore the presence of ionic channels by the patch‐clamp method. Recordings were made from cell‐attached or excised patches of basolateral membrane. Evidence was obtained for the presence of at least two kinds of channels conducting potassium currents. One of these can be shown to be activated by Ca2+.
Guanosine 5'‐triphosphate releases calcium from rat liver and guinea pig parotid gland endoplasmic reticulum independently of inositol 1,4,5‐trisphosphate
Authors: Henne Volkmar , Söling Hans-Dieter
Published: July 2002

GTP releases calcium from rat liver microsomes and guinea pig parotid gland microsomal subfractions independently of the presence of inositol 1,4,5‐trisphosphate (IP3). Non‐hydrolyzable guanine nucleotide analogues have no effect and inhibit the effect of GTP. The mechanism of GTP‐mediated calcium release differs from IP3‐mediated calcium release as indicated by the following findings: (i) GTP‐induced calcium release depends on the presence of compounds which increase the viscosity of the medium (polyethylene glycol, polyvinylpyrrolidone, or bovine serum albumin); (ii) GTP‐mediated calcium release is much slower; (iii) GTP‐mediated calcium release is strongly temperature‐dependent, whereas IP3‐mediated calcium release is not; (iv) GTP‐mediated calcium release is much more sensitive to a decrease of intravesicular free calcium than IP3‐mediated calcium release.
Phenolic antioxidants: potent inhibitors of the (Ca2+ + Mg2+‐ATPase of sarcoplasmic reticulum
Authors: Sokolove Patricia M. , Albuquerque E.X. , Kauffman Frederick C. , Spande Thomas F. , Daly John W.
Published: July 2002

Bis(2‐hydroxy‐3‐tert‐butyl‐5‐methylphenyl)methane (bis‐phenol) is the most potent inhibitor of the (Ca2+ + Mg2+‐ATPase of skeletal muscle sarcoplasmic reticulum yet identified. The compound behaves as a reversible, tight‐binding inhibitor with apparant K
i = 0.3 μM. Butylated hydroxytoluene, butylated hydroxyanisole, and 4‐nonylphenol are also effective inhibitors. These observations are of particular interest in light of the widespread use of such phenolic antioxidants and stabilizers in the food industry and in the manufacture of rubbers and plastics and the ease with which the compounds are extracted into organic solvents.
Tyrosine kinases in normal human blood cells
Authors: Varshney Grish C. , Jöelle'Henry  , Kahn Axel , Phan-Dinh-Tuy Françoise
Published: July 2002

The major tyrosine kinase from platelets was purified as a 51 kDa active enzyme which was shown to be a degradation product of the protooncogene product p60c‐src. Immuno‐depletion experiments using a monoclonal antibody recognizing p60c‐src failed to remove band 3 phosphorylating activity from red blood cell membranes. The erythrocyte tyrosine kinase was not at all immunoprecipitated by this antibody under conditions where the platelet enzyme was immunoprecipitated.
Atrial natriuretic factor receptors and stimulation of cyclic GMP formation in normal and malignant osteoblasts
Authors: Fletcher A.E. , Allan E.H. , Casley D.J. , Martin T.J.
Published: July 2002

Synthetic rat atrial natriuretic factor (Ile‐ANF‐26) stimulated cyclic GMP formation by up to several hundred‐fold in osteoblast‐rich cultures from newborn rat calvaria and in clonal osteogenic sarcoma cells (UMR 106‐01) which are phenotypically osteoblast. ANF had no effect on the cyclic AMP response to parathyroid hormone in the same cells. Specific, high‐affinity binding sites for ANF were identified in both cell types, with Kd and receptor numbers in normal osteoblasts of 1.2 ± 0.1 × 10−10 M and 42 ± 4 × 103 per cell, and in UMR 106‐01 cells of 1.4 ± 0.1 × 10−10M and 22 ± 4 × 103per cell.
Identification of two toxins from scorpion (Leiurus quinquestriatus) venom which block distinct classes of calcium‐activated potassium channel
Authors: Castle Neil A. , Strong Peter N.
Published: July 2002

Two polypeptide toxins from scorpion (Leiurus quinquestriatus) venom which block distinct classes of calcium‐activated potassium channels have been identified and partially purified. One toxin, at 50–100 , blocks apamin‐sensitive potassium fluxes in hepatocytes and inhibits [125I]monoiodoapamin binding. The other, more basic, toxin blocks apamin‐insensitive potassium fluxes in erythrocytes at 200 and, to our knowledge, is the first toxin shown to block the erythrocyte calcium‐activated potassium channel with high affinity. The possible co‐identity of this latter toxin with charybdotoxin is discussed.
Fetuin: The bovine homologue of human α2HS glycoprotein
Authors: Christie D.L. , Dziegielewska K.M. , Hill R.M. , Saunders N.R.
Published: July 2002

The fetal protein fetuin has previously been considered to be confined to species of the order Artiodactyla (cattle, sheep, etc.) in spite of demonstrable biological in vitro effects in tissues of other species [(1983) Comp. Biochem. Physiol. 76A, 241–245]. We have determined the partial amino acid sequence of bovine fetuin and compared it with the published sequence of human α2HS glycoprotein. The N‐terminal 105 residues and a segment aligned with residues 170–225 of α2HS glycoprotein revealed 109 of 161 residues to be identical between the two proteins (68% homology). Mouse polyclonal antibodies to fetuin, and trypsin digest fragments of this protein have been prepared and used for a comparison of native and digested proteins. Polyclonal antibodies to native protein showed little if any cross reactivity. However, antibodies to trypsin digest fragments of fetuin showed obvious cross reactivity with α2HS.
Sequential mechanism of refolding of carbonic anhydrase B
Authors: Semisotnov Gennady V. , Rodionova Natalya A. , Kutyshenko Victor P. , Ebert Bernd , Blanck Jürgen , Ptitsyn Oleg B.
Published: July 2002

The kinetics of refolding of bovine carbonic anhydrase B was studied by a variety of methods over a wide range of times (from milliseconds to hours). It has been shown that protein refolding proceeds through three stages. At the first stage (t
½≈0.03 s) hydrophobic clusters and a compact state of the chain are formed. At the second stage (t
½≈140 s) hydrophobic clusters are desolvated and the rigid native‐like hydrophobic core is formed. At the third stage (t
½≈600 s) the native active protein is formed.
Site‐selective cyclic AMP analogs provide a new approach in the control of cancer cell growth
Authors: Katsaros Dionyssios , Tortora Giampaolo , Tagliaferri Pierosandro , Clair Timothy , Ally Shamsia , Neckers Leonard , Robins Roland K. , Cho-Chung Yoon Sang
Published: July 2002

Site‐selective cyclic AMP analogs bind to site 1 or site 2 of the known cAMP‐binding sites depending on the position of substituents on the purine ring, either at C‐2 and C‐8 (site 1) or at C‐6 (site 2). The growth inhibitory effect of such site‐selective cAMP analogs used in this investigation with 15 human cancer cell lines surpassed that of analogs previously tested. The most potent analogs were 8‐chloro, N
6‐benzyl and N
6‐phenyl‐8‐p‐chlorophenylthio‐cAMP. The combination of a C‐8 with an N
6 analog had synergistic effects. The 24 site‐selective analogs tested produced growth inhibition ranging from 30 to 80% at micromolar concentrations with no sign of toxic effects. Growth inhibition was not due to a block in a specific phase of the cell cycle but paralleled a change in cell morphology, an increase of the RII cAMP receptor protein and a decrease of p21 ras protein. Since the adenosine counterpart of the 8‐chloro analog produced G1 synchronization without affecting the RII and p21 ras protein levels, it is unlikely that an adenosine metabolite is involved in the analog effect. Site‐selective cAMP analogs thus provide a new biological tool for control of cancer growth.
Synthetic analogues of vitamin D3 with an oxygen atom in the side chain skeleton A trial of the development of vitamin D compounds which exhibit potent differentiation‐inducing activity without inducing hypercalcemia
Authors: Abe Junko , Morikawa Makiko , Miyamoto Katsuhito , Kaiho Shin-ichi , Fukushima Masafumi , Miyaura Chisato , Abe Etsuko , Suda Tatsuo , Nishii Yasuho
Published: July 2002

Four analogues of vitamin D3 with an oxygen atom in the side chain skeleton were synthesized to determine whether their differentiation‐inducing activity could be separated structurally from their activity to induce hypercalcemia. The order of the in vitro potency to reduce nitroblue tetrazolium in human myeloid leukemia cells (HL‐60) was 22‐oxa‐1α25‐(OH)2D3 > 1α,25‐(OH)2D3 > 20‐oxa‐1α,25‐(OH)2D3≒22‐oxa‐1α‐(OH) D3 > 1α‐(OH)D3 > 20‐oxa‐1α‐(OH)D3. 22‐Oxa‐1α,25‐(OH)2D3, was also about 10‐times more potent than 1α,25‐(OH)2D3 in suppressing proliferation and inducing differentiation of mouse myelomonocytic leukemia cells (WEHI‐3), but the former was much weaker than the latter in inducing the release of 45Ca from prelabeled fetal mouse calvaria. These results suggest that the differentiation‐inducing activity of vitamin D compounds can be separated structurally from their activity to induce hypercalcemia.
Proton NMR studies of horse ferricytochrome c Completion of the assignment of the well resolved hyperfine shifted resonances
Authors: Santos Helena , Turner David L.
Published: July 2002

1H NMR saturation transfer and nuclear Overhauser effect (NOE) measurements have been used together with two‐dimensional spectra to complete the assignment of the well resolved hyperfine shifted resonances in the spectrum of horse ferricytochrome c and obtain their shifts in the reduced protein. New assignments include the β‐CH2 protons of Met‐80, both ring protons of His‐18, and the α‐CH2 of Gly‐29 and δ‐CH2 of Pro‐30, which resonate surprisingly far upfield despite the absence of any Fermi contact contribution to the shift.
Is enhanced free radical flux associated with increased intracellular proteolysis?
Authors: Vince Gillian S. , Dean Roger T.
Published: July 2002

Intracellular proteolysis was measured in cultured cells during and after radical attack. Radicals were generated firstly, throughout the aqueous phase by gamma irradiation and secondly, selectively, either extracellularly or intracellularly by chemical and enzymic methods. With both approaches, stimulation of proteolysis was observed in certain circumstances. Phenylhydrazine stimulated proteolysis at low concentration but inhibited at higher. Depletion of the antioxidant glutathione and inhibition of catalase also increased proteolysis.
Correlation among sites of limited proteolysis, enzyme accessibility and segmental mobility
Authors: Novotný Jiří , Bruccoleri Robert E.
Published: July 2002

The relationship among accessibility to an enzyme, flexibility, and limited proteolysis was explored. Regions accessible to large probes, comparable in size to proteolytic enzymes, were computed in the crystallographic structures of thermolysin, trypsinogen and ribonuclease. Positions of these accessible regions were compared with sites of autolytic/proteolytic attacks, and with locations of flexible backbone segments. All the proteolytic sites were found to be exceptionally accessible. Most of them were also flexible, but at least one prominent site in trypsinogen appeared to be rigid. Thus, surface exposure seems to be more essential to proteolysis than flexibility.
Intracellular pH and cell adhesion to solid substrate
Authors: Margolis L.B. , Rozovskaja I.A. , Cragoe E.
Published: July 2002

It was shown that activation of the Na+/H+ antiporter resulting in an increase of intracellular pH (pHi) by 0.2–0.3 is a necessary stage of cell stimulation by soluble growth factors. Solid substrate can also be formally regarded as a growth factor since adhesion stimulates proliferation of various cell types. In the present study we have found that the attachment of mouse embryo fibroblasts to solid substrate is followed by an increase of pHi by approx. 0.3 units. pH shift occurs after the cell attaches to the substrate and is obligatory for cell spreading. The evidence for Na+/H+ antiporter involvement in the increase of pHi in substrate‐attached cells is presented. It is suggested that signals for cell proliferation by chemical (soluble ligands) and physical (solid substrate) growth factors are transmitted similarly.
Na+, K+‐ATPase: Tissue‐specific expression of genes coding for α‐subunit in diverse human tissues
Authors: Sverdlov E.D. , Akopyanz N.S. , Petrukhin K.E. , Broude N.E. , Monastyrskaya G.S. , Modyanov N.N.
Published: July 2002

The expression of genes coding for α and αiii isoforms of Na+,K+‐ATPase α‐subunit has been studied in human kidney, brain, thyroid and liver cells. The expression was shown to be subjected to a tissue‐specific control and also depended on the developmental stage. The tissue‐specific expression of genes coding for different isoforms of the catalytic subunit of Na+,K+‐ATPase perhaps may be attributed to various functions of proteins belonging to this family.
The fluorescence intensity of the lipophilic probe N‐phenyl‐1‐naphthylamine responds to the oxidation‐reduction state of purified Escherichia coli cytochrome o incorporated into phospholipid vesicles
Authors: Sedgwick Edward G. , Bragg Philip D.
Published: July 2002

N‐Phenyl‐1‐naphthylamine (NPN), a reagent which has been used previously to probe the fluidity or microviscosity of the membrane lipids of intact cells of Escherichia coli, was found to respond to the redox state of purified cytochrome o incorporated into lipid vesicles formed from purified or E. coli phospholipids. NPN was bound to the proteoliposomes to produce a steady‐state level of fluorescence intensity. Addition of the substrate ascorbate, in the presence of phenazine methosulfate as an electron donor, did not alter the fluorescence. However, following complete removal of oxygen from the medium by oxidation of the substrate by molecular oxygen catalyzed by cytochrome o, there was an increase in the fluorescence of NPN. This coincided with the reduction of cytochrome o. Reoxidation of the cytochrome by addition of oxygen decreased the fluorescence to steady‐state levels until the oxidant had been completely reduced. The fluorescence changes were dependent on the incorporation of cytochrome o into phospholipid vesicles but were insensitive to the state of energization of the vesicle membrane.
Cloned rat M3 muscarinic receptors mediate phosphoinositide hydrolysis but not adenylate cyclase inhibition
Authors: Pinkas-Kramarski Ronit , Stein Reuven , Zimmer Yitzhak , Sokolovsky Mordechai
Published: July 2002

Rat M3 mAChR subtype was stably expressed in RAT 1 cells. Investigation of the pharmacological and biochemical properties of the cloned M3 receptors revealed that they mediate phosphoinositide hydrolysis but not adenylate cyclase inhibition. The similarities and differences between the properties of cloned rat M1 and M3 receptors are discussed.
Tissue distribution of mRNAs encoding muscarinic acetylcholine receptor subtypes
Authors: Maeda Akito , Kubo Tai , Mishina Masayoshi , Numa Shosaku
Published: July 2002

The tissue distribution of the mRNAs encoding muscarinic acetylcholine receptors (mAChRs) I, II, III and IV has been investigated by blot hybridization analysis with specific probes. This study indicates that exocrine glands contain both mAChR I and III mRNAs, whereas smooth muscles contain both mAChR II and III mRNAs. All four mAChR mRNAs are present in cerebrum, whereas only mAChR II MRNA is found in heart.
Somatostatin activates glibenclamide‐sensitive and ATP‐regulated K+ channels in insulinoma cells via a G‐protein
Authors: Fosset Michel , Schmid-Antomarchi Heidy , de Weille Jan R. , Lazdunski Michel
Published: July 2002

Somatostatin, an hyperglycemia‐inducing hormone, was studied in rat insulinoma (RINm5F) cells using 86Rb+ efflux techniques. 86Rb+ efflux is stimulated by somatostatin in a dose‐dependent manner. The half‐maximum value of activation is 0.7 nM. Somatostatin‐induced 86Rb+ efflux is abolished by the hypoglycemia‐inducing sulfonylurea, glibenclamide, a known blocker of ATP‐regulated K+ channels. Somatostatin activation is prevented by pretreatment of insulinoma cells with pertussis toxin. 86Rb+ efflux studies show that somatostatin activates an ATP‐dependent K+ channel.
The synthesis of human α‐2‐HS glycoprotein is down‐regulated by cytokines in hepatoma HepG2 cells
Authors: Daveau Maryvonne , Christian-Davrinche  , Julen Nathalie , Hiron Martine , Amaud Philippe , Lebreton Jean-Pierre
Published: July 2002

The regulation of the synthesis of α‐2‐HS glycoprotein (AHSG) by inflammatory mediators from activated monocytes was studied on the human hepatoma cell line HepG2 and compared to that of albumin. Monocyte‐conditioned medium, recombinant human interleukin‐6 (rhIL6) and interleukin‐1β(rhIL1β) all down‐regulated the synthesis of AHSG. This decrease was found both at the protein and the mRNA level. The most efficient mediator was the monocyte‐conditioned medium, when rhIL1β was found to be less efficient than rhIL6. The combination of rhIL6 and rhIL1β resulted in an additive down‐regulation of the AHSG mRNA levels. Similar results were obtained with albumin. These data indicate that AHSG is a negative acute‐phase protein whose synthesis is regulated by cytokines in a manner similar to that of albumin.
A cytolytic δ‐endotoxin from Bacillus thuringiensis var. israelensis forms cation‐selective channels in planar lipid bilayers
Authors: Knowles Barbara H. , Blatt Michael R. , Tester Mark , Horsnell Jane M. , Carroll Joe , Menestrina Gianfranco , Ellar David J.
Published: July 2002

In order to determine the mechanism of action of the 27 kDa mosquitocidal δ‐endotoxin of Bacillus thuringiensis var. israelensis we have studied its effects on the conductance of planar lipid bilayers. The toxin formed cation‐selective channels in the bilayers, permeable to K+ and Na+ but not to N‐methylglucamine or Cl−, showing very fast, cooperative opening and closing. Channel opening was greatly reduced in the presence of divalent cations (Ca2+, Mg2+) and the effect was reversed when these ions were removed. These results are consistent with our proposal that B. thuringiensis toxins act by a mechanism of colloid‐osmotic lysis.
Effect of persistent measles virus infection on protein kinase C activity and c‐fos protooncogene expression in neuroblastoma cells
Authors: Wolfson M. , Katorza A. , Segal S. , Rager-Zisman B.
Published: July 2002

The effect of persistent measles virus infection on c‐fos protooncogene and protein kinase C (PKC‐I) gene expression in a murine neuroblastoma cell line was studied. Overexpression of c‐fos protooncogene by infected NS20Y/MS cells was detected when compared with uninfected NS20Y cells. The level of PKC‐I‐specific mRNA was increased in infected NS20Y/MS cells. In addition, the level of total PKC activity in these cells was also enhanced. We conclude that persistent measles virus infection can alter both protooncogene expression and signal transduction in cells of neuronal origin.
Functional reconstitution of rat ovarian LH/hCG receptor into proteoliposomes
Authors: Kolena Jaroslav
Published: July 2002

Rat ovarian membrane LH/hCG receptor was solubilized in various detergents and reconstituted into proteoliposomes. Upon removal of sodium cholate by active absorption on Bio‐Beads SM‐2, the functional interaction between receptor and adenylate cyclase was restored. Adenylate cyclase was stimulated by hCG, HCG+GTP or GppNHp and NaF. Reconstituted proteoliposomes bound more 125I‐hCG (528 fmol/mg protein) than membrane‐bound receptors (384 fmol/mg protein). There was no difference, however, in the relative affinity of reconstituted receptor preparations for hCG.
Na+‐independent Mg2+ efflux from Mg2+‐loaded human erythrocytes
Authors: Günther T. , Vormann J.
Published: July 2002

Net Mg2+ efflux from Mg2+‐loaded human erythrocytes was maximal after reincubation in sucrose. Net Mg2+ efflux was not inhibited by furosemide or bumetanide and, therefore, was not performed by the (Na,K,Cl)‐ or (K,Cl)‐cotransport system. A component of net Mg2+ efflux was inhibited by extracellular NaCl, KCl, LiCl, choline Cl and SITS, in analogy to the inhibition of net Cl− and SITS. Therefore, it was concluded that net Mg2+ efflux is dependent on net Cl− efflux for charge compensation. Cl−‐dependent net Mg2+ efflux was inhibited by amiloride. Only 10% of the maximal net Mg2+ efflux may depend on extracellular Na+.
Rapid myosin phosphorylation transients in phasic contractions in chicken gizzard smooth muscle
Authors: Fischer W. , Pfitzer G.
Published: July 2002

In intact smooth muscle strips from chicken gizzard, electrical stimulation and carbachol elicited brief, phasic contractions which were associated with a very rapid, transient phosphorylation of the 20 kDa myosin light chains. The phosphorylation transients reached their peak after 3 s and 6 s and preceded that of force. Phosphorylation was not significantly different from basal levels after 10 s and 30 s while force still amounted to 50% of the peak value. The rate of tension decline could be increased by cessation of stimulation or by addition of atropine, even at apparently basal phosphorylation levels suggesting a phosphorylation independent regulation.
Differential expression of sodium channel mRNAs in rat peripheral nervous system and innervated tissues
Authors: Beckh Synnöve
Published: July 2002

RNA blot hybridization analyses using probes specific for sodium channels I, II and III revealed high levels of sodium channel I mRNA and low levels of sodium channel II and III mRNAs in peripheral nervous system (PNS) tissues. The developmental expression patterns of these mRNAs were generally similar to those described for the central nervous system. The small amounts of sodium channel I and III mRNAs present in tongue muscle were greatly reduced after partial denervation. Expression of the three sodium channels thus appears to be restricted to the nervous system. Putative novel additional mRNAs, specifically expressed in the PNS, were detected with a probe that recognizes nucleotide sequences common to sodium channels I, II and III.
The primary structure of rat ribosomal protein S7
Authors: Suzuki Katsuyuki , Olvera Joe , Wool Ira G.
Published: July 2002

The amino acid sequence of the rat 40S ribosomal subunit protein S7 was deduced from the sequence of nucleotides in two recombinant cDNAs and confirmed from the amino acid sequence of a cyanogen bromide peptide obtained from the protein. Ribosomal protein S7 has 194 amino acids and has a molecular mass of 22113. Hybridization of the cDNA to digest of nuclear DNA suggests that there are 14–16 copies of the S7 gene. The mRNA for the protein is about 725 nucleotides in length. Rat S7 is homologous with Xenopus laevis S8. The protein contains a possible internal duplication of 10 residues.
Conversion of big endothelin‐1 to endothelin‐1 by two types of metalloproteinases derived from porcine aortic endothelial cells
Authors: Matsumura Yasuo , Ikegawa Ruriko , Tsukahara Yaeko , Takaoka Masanori , Morimoto Shiro
Published: July 2002

Incubation of big endothelin‐1 (big ET‐11–39) with either the cytosolic or membrane fraction obtained from cultured endothelial cells, resulted in an increase in immunoreactive‐endothelin (IR‐ET), which was markedly inhibited by metal chelators. Phosphoramidon, a metalloproteinase inhibitor, specifically suppressed the membrane fraction‐induced increase in IR‐ET, whereas the increase in IR‐ET observed with the cytosolic fraction was not influenced by phosphoramidon. Reverse‐phase (RP)‐HPLC of the incubation mixture of big ET‐1 with the cytosolic or membrane fraction revealed one major IR‐ET component corresponding to the elution position of synthetic ET‐11–21. Simultaneously, immunoreactivities like the C‐terminal fragment (CTF22–39) of big ET‐1 were present, as deduced from the RP‐HPLC coupled with the radioimmunoassay for CTF. Our results indicate the presence of two types of metalloproteinases, which convert big ET‐1 to ET‐1 via a single cleavage between Trp21 and Val22, in vascular endothelial cells.