bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oligomeric hepatoproliferin disaggregates into an active monomer that was purified and forcefully dissociated into two different ionic species
Authors: Oosthuizen Mathys M.J. , Lambrechts Hugo 
Published: December 2008

AbstractHepatoproliferin (HPF), a liver regeneration factor, was isolated initially as an aggregated molecule (big‐HPF) and was purified into two homogeneous, bioactive species of 14 kDa and 18.5 kDa. These two big‐HPFs were disaggregated to completion into two monomeric forms (small‐HPFs) when incubated for 10 days in 0.15 M ammonium bicarbonate at 25°C. Both monomeric forms were purified to homogeneity as active entities, one with a molecular mass of 944 Da and one with a molecular mass of 1066 Da. Each of the two 35S‐labelled small‐HPFs was found, by enzymic analysis, to contain a charged sulfonated saccharide, which was neutralized by a specific amine. Monomeric HPF is therefore a stable ionic complex formed between these two ionic species. So strong was the electrostatic association that small‐HPF remained intact in solution and no amine was displaced by the ammonium ions of the buffer. Small‐HPF remained unimpaired during purification, since all activity was retained despite alternating acidic and basic conditions. However, when small‐HPF was brought into contact with either a cationic or an anionic resin, it was dissociated to completion when mixed continuously with the resin for 4 days. The ionic entity that was released had no bio‐activity and was either a pure radioactively labeled saccharide or a non‐labeled amine, depending on the kind of resin used. When incubated together, the separated counterions combine to regain full activity after 2 days of reassociation. However, with incubation for longer, this reassociated small‐HPF formed different oligomeric HPFs by aggregation.Small‐HPF is therefore a new kind of growth enhancer, consisting of an acidic sulfonated saccharide and a basic amine assembled into a stable active ionic complex that has a tendency to aggregate.
Plasma membrane‐generated reactive oxygen intermediates and their role in cell growth of plants
Authors: Schopfer P. , Liszkay A. 
Published: December 2008

AbstractReactive oxygen species (ROS) produced as intermediates in the reduction of O2 to H2O (superoxide radical, hydrogen peroxide, hydroxyl radical), are generally regarded as harmful products of oxygenic metabolism causing cell damage in plants, animals and microorganisms. However, oxygen radical chemistry can also play useful roles if it takes place outside of the protoplast. In plants, the production of these ROS initiated by the plasma membrane NAD(P)H oxidase can be used for controlled polymer breakdown leading to wall loosening during extension growth. Backbone cleavage of cell wall polysaccharides can be accomplished by hydroxyl radicals produced from hydrogen peroxide and superoxide in a reaction catalyzed by cell wall peroxidase. Growing plant organs such as coleoptiles or roots of maize seedlings produce these ROS specifically in the apoplast of actively growing tissues, e.g. in the epidermis of the coleoptile and the growing zone of the root. Auxin promotes the release of hydroxyl radicals when inducing elongation growth. Experimental generation of hydroxyl radicals in the wall causes an increase in wall extensibility in vitro and replaces auxin in inducing growth. Auxin‐induced growth can be inhibited by scavengers of ROS or inhibitors interfering with the formation of these molecules in the cell wall. These results provide the experimental background for a novel hypothesis on the mechanism of plant cell growth in which the generation of hydroxyl radicals, initiated by the plasma membrane NAD(P)H oxidase, plays a central role.
ATP‐ and growth substance‐dependent cell‐free enlargement of plasma membrane vesicles from soybean
Authors: Auderseta Guy , Morré D.J. 
Published: December 2008

AbstractGrowth hormone‐responsive and nucleoside triphosphate‐dependent enlargement of inside‐out vesicles of plasma membranes from soybeans prepared by aqueous two‐phase partition and everted by freezing and thawing has been achieved in a cell‐free system. In the presence of 100 μM ATP in 40 mM HEPES buffer, pH 7, enlargement of isolated plasma membrane vesicles was accelerated by the synthetic plant growth factor, 2,4‐dichlorophenoxyacetic acid (2,4‐D), compared to ATP alone, 2,4‐D alone or no additions. After 20 min with 1 μM 2,4‐D, vesicles increased in diameter, 20% on average. Although vesicle diameters in the presence or absence of 2,4‐D overlapped, the means were clearly separated. The 20% increases in diameter corresponded to a doubling of vesicle volume. Both 100 μM ATP and 1 μM 2,4‐D were necessary to stimulate the cell‐free vesicle enlargement. In the presence of 1 μM 2,4‐D, enlargement observed with 100 μM ATP was greater than with either 10 μM ATP or 500 μM ATP alone. In the presence of 100 μM ATP, vesicle enlargement was proportional to the logarithm of 2,4‐D concentration. With the growth‐inactive 2,4‐D analog, 2,3‐D, no vesicle enlargement was observed either alone or in the presence of 100 μM ATP. Right side‐out vesicles did not enlarge in response to either ATP, 2,4‐D or the two in combination suggesting that the responsible ATP site was on the inside of the cell.
Inside‐out but not right side‐out plasma membrane vesicles from soybean enlarge when treated with ATP + 2,4‐D as determined by electron microscopy and light scattering: Evidence for involvement of a plasma membrane AAA‐ATPase
Authors: Hicks‐Bergera Carrie , Morreb D. James 
Published: December 2008

AbstractThe concept that the location of an AAA‐ATPase associated with the plant plasma membrane may be indicative of a functional relationship to growth or cell enlargement by analogy with roles in physical membrane displacements as proposed for AAA‐ATPases associated with internal membranes was tested. A plant growth hormone‐responsive and nucleoside triphosphate‐dependent enlargement of inside‐out vesicles of plasma membranes from soybeans was utilized in a completely cell‐free system. The rate of enlargement was accelerated by the synthetic plant growth factor 2,4‐dichlorophenoxyacetic acid (2,4‐D) in a log dose‐dependent manner and was increased approximately 2‐fold with the addition of 1 μM 2,4‐D plus 100 μM ATP compared to 100 μM ATP alone, 1 μM 2,4‐D alone or no additions. The cell‐free enlargement was inhibited by AAA‐ATPase‐specific antisera and by CoCl2, an inhibitor specific for AAA‐ATPases. The responsible ATP site appears to be on the inside of the cell, since right side‐out vesicles did not enlarge in response to either ATP, 2,4‐D or the two in combination.
ATP‐Dependent and drug‐inhibited vesicle enlargement reconstituted using synthetic lipids and recombinant proteins
Authors: Morre D.James , Kim Chinpal , Hicks‐Berger Carrie 
Published: December 2008

AbstractA recombinant ECTO‐NOX (tNOX) and a recombinant plasma membrane associated AAA‐ATPase (ATPase Associated with Different Cellular Activities) were combined in stoichometric proportions into liposomes together with al‐bumin as a source of protein thiols. Large lamellar vesicles were formed from phosphatidylcholine, cholesterol and dicetyl phosphate in a molar ratio of 50:45:5, where the phosphatidylcholine was a 2:1 mixture of synthetic dimyristoyl and dipalmitoyl phosphatidylcholines. The lipids were dried to a film and reconstituted into vesicles by resuspension in buffer containing the recombinant proteins in equimolar ratios of 0.04 nmoles/mg lipid. In the presence of ATP, these vesicles enlarged in an ATP‐dependent manner based on light‐scattering measurements. Because the drug‐inhibited ECTO‐NOX protein, tNOX was utilized, the enlargement was inhibited by capsaicin, a quinone site tNOX inhibitor specific for tNOX. With the lipid vesicle systems, the recombinant ECTO‐NOX, the recombinant AAA‐ATPase, a source of protein thiols and ATP all were required. In control experiments, no ATP‐dependent vesicle enlargement was observed with the AAA‐ATPase or the ECTO‐NOX protein alone. Also addition of ATP was without any effect when only the single proteins were incorporated into the lipid vesicles. A model has been developed whereby the plasma membrane AAA‐ATPase is linked via disulfide bonds, formed and broken by the ECTO‐NOX protein, to membrane structural proteins. Binding of ATP and subsequent hydrolysis and release of ADP would advance the ATPase hexamer ratchet thereby both thinning the membrane and increasing the vesicle surface.
Effect of polyclonal antisera to recombinant tNOX protein on the growth of transformed cells
Authors: Chen Chun‐Feng , Huang Shing , Liu Shan‐Chi , Chueh Pin Ju 
Published: December 2008

AbstractPrevious reports have described a tumor‐associated NADH oxidase (tNOX) and its continuous activation in transformed culture cells. Certain anticancer drugs have been shown to inhibit preferentially both the tNOX activity and the growth of transformed culture cells and the cytotoxicity is associated with the induction of apoptosis. To investigate the biological function of tNOX protein, we have raised polyclonal antisera against bacterial expressed tNOX protein and the antisera are able to recognize protein bands in transformed cells but not the non‐transformed cells tested. With tNOX antisera treatment, the survival in transformed cell lines is decreased but not the non‐transformed cells. In addition, tNOX antisera‐induced cytotoxicity is accompanied by the induction of apoptosis. However, slightly higher amount of PARP cleavage and activation of caspase‐9 are observed in tNOX antisera treated HCT116 cells. Further experiments have demonstrated the activation of JNK and phosphorylation of p53 by treatment. In addition, tNOX antisera treatment leads to an impressive increase in reactive oxygen species in COS cells but not the control sera. Our data suggest that (a) tNOX antisera treatment may inhibit the growth of transformed cells by inducing apoptosis and (b) the apoptotic mechanism might be through modulating ROS production and JNK pathway.
A plasma membrane‐associated AAA‐ATPase from Glycine max
Authors: Hicks‐Berger Carrie , Sokolchik Irina , Kim Chinpal , Morré D. James 
Published: December 2008

AbstractAn AAA‐ATPase (ATPases Associated with a Variety of Cellular Activities) localized to the plasma membrane of soybean (Glycine max) was isolated, partially sequenced and cloned (SBPM AAA‐ATPase). The protein with an apparent monomer molecular mass of about 97 kDa was isolated using a combination of anion exchange, preparative SDS‐PAGE, reverse phase HPLC, and ATP affinity chromatography. The cDNA for the full‐length SBPM AAA‐ATPase was cloned by screening an expression library using an antibody against the highly conserved Walker B AAA‐ATP‐binding motif. Northern blot analysis detected one transcript of ∼2700 bp. The full‐length cDNA sequence was that previously obtained (GenBank Database; U20213) encoding a protein with two copies of the conserved AAA‐ATP‐binding motif and regions of sequence homology with other AAA‐ATPases. Electron microscopic preparations of the recombinant SBPM AAA‐ATPase revealed hexamers typically formed by these proteins. The cloned and expressed protein was identical to the protein isolated from the soybean plasma membrane as confirmed using antisera raised to a non‐conserved region of the derived protein sequence and by N‐terminal sequencing of peptides derived from the isolated protein.
Drastic effect of several caffeic acid derivatives on the induction of heme oxygenase‐1 expression revealed by quantitative real‐time RT‐PCR
Authors: Suzuki Keiko , Tanaka Izumi , Nakanishi Ikuo , Kurematsu Ayako , Yakumaru Haruko , Ikota Nobuo , Ishihara Hiroshi 
Published: December 2008

AbstractAmong antioxidative polyphenols, caffeic acid esters such as caffeic acid phenethyl ester (CAPE) and chlorogenic acid are contained in propolis, vegetables and coffee. In this study, we compared the efficacy of some polyphenols on the activation level of a cytoprotective heme oxygenase‐1 (HO‐1) gene in RAW264.7 mouse macrophage cells using quantitative real‐time RT‐PCR. The quantitative study revealed a variety of activation level of HO‐1 gene by the chemicals. CAPE and caffeic acid ethyl ester (CAEE) at the final concentration of 2 μM drastically activated the HO‐1 gene to 39.2‐fold and 20.1‐fold, respectively. Curcumin, structurally related with caffeic acid and an element of turmeric, induced the HO‐1 gene to 5.8‐fold. In contrast, no activation was observed by other caffeic acid esters such as chlorogenic acid and rosmarinic acid. Higher concentrations were necessary for the activation by an antioxidant cysteamine and the electrophile diethyl maleate. Although the inducible activities of CAPE and chlorogenic acid were distinctly different, they showed similar reductive capacities when determined by cyclic voltammetry. These results show that the drastic activation of HO‐1 gene by CAPE and CAEE is dependent upon their chemical structures, rather than the reductive activity of polyphenols, possibly reflecting the physiological effects of the nutritional elements.
Isoliquiritigenin (ISL) inhibits ErbB3 signaling in prostate cancer cells
Authors: Jung Jae In , Chung Eunkyung , Seon Mi Ra , Shin Hyun‐Kyung , Kim Eun Ji , Lim Soon Sung , Chung Won‐Yoon , Park Kwang‐Kyun , Park Jung Han Yoon 
Published: December 2008

AbstractIsoliquiritigenin (ISL), a flavonoid found in licorice, shallot, and bean sprouts, has been identified as a potent anti‐tumor promoting agent. We previously demonstrated that ISL reduces cell proliferation and induces apoptosis in DU145 human prostate cancer cells and MAT‐LyLu (MLL) rat prostate cancer cells. Overexpression of members of the ErbB receptor family is a frequently observed event in several human cancers, and ErbB receptors currently constitute the primary targets of anticancer strategies. In order to elucidate the mechanisms underlying the ISL regulation of prostate cancer cell proliferation, the present study attempted to determine whether ISL inhibits heregulin (HRG)‐&&num;946;‐induced ErbB3 signaling. DU145 and MLL cells were cultured in serum‐free medium with ISL and/or HRG‐&&num;946;. Exogenous HRG‐&&num;946; alone was shown to effect an increase in the numbers of viable cells, whereas HRG‐&&num;946; did not counteract the ISL‐induced growth inhibition. ISL reduced the protein and mRNA levels of ErbB3 in a dose‐dependent manner, but exerted no effect on HRG protein levels. Immunoprecipitation/Western blot studies indicated that ISL inhibited the HRG‐&&num;946;‐induced tyrosine phosphorylation of ErbB3, the recruitment of the p85 regulatory subunit of phosphatidylinositol 3‐kinase (PI3K) to ErbB3, and Akt phosphorylation in DU145 cells. These results indicate that ISL inhibits the proliferation of prostate cancer cells, at least in part, via the inhibition of ErbB3 signaling and the PI3K/Akt pathway.
Flavonoid content in leaf extracts of the fig (Ficus carica L.), carob (Ceratonia siliqua L.) and pistachio (Pistacia lentiscus L.)
Authors: Vaya Jacob , Mahmood Saeed 
Published: December 2008

AbstractThe total flavonoid content of leaf extracts (70% ethanol) from fig (Ficus carica L.), carob (Ceratonia siliqua L.) and pistachio (Pistacia lentiscus L.) plants were determined by using reverse phase high‐performance liquid chromatography (HPLC)‐and analyzed by UV/VIS array and electrospray ionization (ESI)‐mass spectrometry (MS) detectors. As a base for comparison, flavonoid type and level were also determined in extracts from soybeans and grape seeds. It was found that the major flavonoids in Ficus are quercetin and luteolin, with a total of 631 and 681 mg/kg extract, respectively. In Ceratonia leaves, nine different flavonoids were detected. The major one was myricetin (1486 mg/kg extract), with a similar level in Pistacia (1331 mg/kg extract, myricetin). The present study is the first to report the presence of the isoflavone genistein in the Pistacia leaf, which was discovered to consist of about a third of the genistein level detected in soybean.
Effect of atorvastatin withdrawal on circulating coenzyme Q10 concentration in patients with hypercholesterolemia
Authors: Chu Chih‐Sheng , Kou Hwang‐Shang , Lee Chun‐Jing , Lee Kun‐Tai , Chen Su‐Hwei , Voon Wen‐Chol , Sheu Sheng‐Hsiung , Lai Wen‐Ter 
Published: December 2008

AbstractStatin therapy can reduce the biosynthesis of both cholesterol and coenzyme Q10 by blocking the common upstream mevalonate pathway. Coenzyme Q10 depletion has been speculated to play a potential role in statin‐related adverse events, and withdrawal of statin is the choice in patients developing myotoxicity or liver toxicity. However, the effect of statin withdrawal on circulating levels of coenzyme Q10 remains unknown. Twenty‐six patients with hypercholesterolemia received atorvastatin at 10 mg/day for 3 months. Serum lipid profiles and coenzyme Q10 were assessed before and immediately after 3 months and were also measured 2 and 3 days after the last day on the statin. After 3 months' atorvastatin therapy, serum levels of total cholesterol (TC), low‐density lipoprotein cholesterol (LDL‐C) and coenzyme Q10 (0.43 ± 0.23 to 0.16 ± 0.10 μg/mL) were all significantly reduced (all p < 0.001). On day 2 after the last atorvastatin, the coenzyme Q10 level was significantly elevated (0.37 ± 0.16 μg/mL) and maintained the same levels on day 3 (0.39 ± 0.18 μg/mL) compared with those on month 3 (both p < 0.001), while TC and LDL‐C did not significantly change within the same 3 days. These results suggest that statin inhibition of coenzyme Q10 synthesis is less strict than inhibition of cholesterol biosynthesis.
Effect of polaprezinc on taste disorders in zinc‐deficient rats
Authors: Hamano Hiroki , Yoshinaga Koji , Eta Runa , Emori Yutaka , Kawasaki Daisuke , Iino Yuka , Sawada Miwa , Kuroda Hiroyuki , Takei Mineo 
Published: December 2008

AbstractThe effect of polaprezinc, a chelate compound consisting of zinc ion and L‐carnosine, on abnormalities of taste sensation induced by feeding a zinc‐deficient diet to rats was examined by using the two‐bottle preference test (quinine hydrochloride as a bitter taste and sodium chloride as a salty taste). Rats were fed either a zinc‐deficient or a zinc‐sufficient diet. The zinc‐deficient diet increased the preference for both taste solutions, while polaprezinc (at doses of 3 and 10 mg/kg) restored the altered taste preferences. We also evaluated the proliferation of taste bud cells using 5‐bromo‐2′‐deoxyuridine (BrdU). The BrdU incorporation into taste bud cells was significantly reduced in rats fed a zinc‐deficient diet compared with rats fed a zinc‐sufficient diet (from 50.8% to 45.0%, p < 0.05) and this reduction was reversed by polaprezinc at doses of 1, 3, and 10 mg/kg, increasing to 50.2%, 53.5%, and 52.5%, respectively. These findings indicate that zinc deficiency induces the delayed of proliferation of taste bud cells, while polaprezinc improves cell proliferation. In conclusion, polaprezinc had a therapeutic effect in a rat model of abnormal taste sensation. Its mechanism of action was suggested to involve improvement of the decrease in taste bud cell proliferation caused by zinc deficiency.
Effects of boron and calcium supplementation on mechanical properties of bone in rats
Authors: Naghii Mohammad Reza , Torkaman Giti , Mofid Mahmood 
Published: December 2008

AbstractObjective: The objective of this study was to consider the effects of boron (B) and calcium (Ca) supplementation on mechanical properties of bone tissues and mineral content of the selected bones in rats.Methods: Adult male Sprague Dawley rats underwent three different treatments with boron and calcium in their drinking water, while taking diet ad libitum for 4 weeks. Rats in the three treatment groups received 2 mg B/d, 300 mg Ca/d, and a combination of 2 mg B+ 300 mg Ca/d, respectively. After the experimental period body weights were recorded and bone mechanical properties were determined on the tibiae, femurs, and fifth lumbar vertebral bones and the mineral contents of these bones was calculated as the ash percentage.Results: Better measurement of bone mechanical properties were observed for boron supplementation. The stiffness of the lumbar vertebral bones tended to increase in all groups and was significant for Ca supplementation. The significant maximal load obtained for boron in all bones indicates higher strength and less strength for apparently a high level of calcium, while this negative defect in the case of lumbar vertebral bones was corrected in the presence of boron. Highest mean energy to maximal load was shown with boron supplementation, demonstrating significant values with Ca group, and lower energy for the lumbar vertebral bones in Ca group in comparison with the controls. Less deformation at the yield points was shown in Ca group. There were no significant differences in ash weights among the four groups.Conclusions: Additional and longer studies are warranted to further determine the effects of supplemental boron with different calcium levels and possibly other minerals involved in bone mechanical properties in rats.
Holistic and network analysis of meningioma pathogenesis and malignancy
Authors: Tao Yingqun , Wei Qing , Xu Zaihua , Bai Rulin , Li Yao , Luo Chun , Dong Yan , Gao Guoyi , Lu Yicheng 
Published: December 2008

AbstractMeningiomas, which originate from arachnoid cells and constitute the largest subgroup of all intracranial tumors, are generally benign, yet have the capacity to progress into a higher histological grade of malignancy associated with an increase in biological aggressivity and/or capacity to recur. To elucidate meningioma pathogenesis and malignancy, we applied a holistic and network approach analyzing cDNA and tissue microarray results. A potential pathway leading to meningioma angiogenesis, apoptosis and proliferation was evidenced as well as a regulatory network of the biomarkers including Ki‐67, AR, CD34, P53, c‐MYC, etc. which might support clinical research. In this potential pathway, ITGB1 could be the most important “superoncogene” playing a vital role in apoptosis and proliferation, while FOXO3A, MDM4 and MT3 are important to the malignancy process. Some genes are first reported that could explain why radiation induces meningioma and why more female than male patients are affected. Further, we present the hypothesis that HIV‐Tat protein might have a close relationship with meningioma pathogenesis and malignancy.
Macelignan protects HepG2 cells against tert‐butylhydroperoxide‐induced oxidative damage
Authors: Sohn Jong Hee , Han Kyu Lee , Choo Jeong Han , Hwang Jae‐Kwan 
Published: December 2008

AbstractIn this study, we investigated the protective effect of macelignan, isolated from Myristica fragrans Houtt. (nutmeg) against tert‐butylhydroperoxide (t‐BHP)‐induced cytotoxicity in a human hepatoma cell line, HepG2. The tetrazolium dye colorimetric test (MTT test) and lactate dehydrogenase (LDH) assay were used to monitor cell viability and necrosis, respectively. Lipid peroxidation [malondialdehyde (MDA) formation] was estimated by the fluorometric method. Intracellular reactive oxygen species (ROS) formation was measured using a fluorescent probe 2′,7′‐dichlorofluorescein diacetate (DCFH‐DA), and DNA damage was detected using single cell gel electrophoresis (comet assay). The results showed that macelignan significantly reduced the cell growth inhibition and necrosis caused by t‐BHP. Furthermore, macelignan ameliorated lipid peroxidation as demonstrated by a reduction in MDA formation in a dose‐dependent manner. It was also found that macelignan reduced intracellular ROS formation and DNA damaging effect caused by t‐BHP. These results strongly suggest that macelignan has significant protective ability against oxidative damage caused by reactive intermediates