Biomedical subjects

T B Ng

Publications and source records attributed to T B Ng.

At least 109 records · Page 6Linked to original sources

PubMed2003

Alocasin, an anti-fungal protein from rhizomes of the giant taro Alocasia macrorrhiza.

An anti-fungal protein designated alocasin was isolated from the rhizomes of the giant taro Alocasia macrorrhiza. The isolation protocol involved ion exchange chromatography on diethylaminoethyl (DEAE)-cellulose, ion exchange chromatography on sulfopropyl (SP)-Sepharose, and gel filtration on Superdex 75. Alocasin, which was unadsorbed on DEAE-cellulose and SP-Sepharose, possessed the N-terminal sequence APEGEV, which exhibited some similarity to that of the miraculin-like anti-fungal protein from Pisum sativum legumes. It demonstrated a molecular mass of 11kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration, and displayed anti-fungal activity against Botrytis cinerea. Alocasin reduced the activity of HIV-1 reverse transcriptase. It exhibited weak hemagglutinating activity, only at a concentration of 1mg/ml.

Alocasia↗

PubMed2003

Isolation of a novel N-acetylglucosamine-specific lectin from fresh sclerotia of the edible mushroom Pleurotus tuber-regium.

An N-acetylglucosamine-binding lectin with a molecular mass of 32kDa was isolated from fresh sclerotia of the edible mushroom Pleurotus tuber-regium. Its N-terminal sequence exhibited some similarity to that of Agaricus bisporus lectin. The isolation procedure was simple, involving (NH(4))(2)SO(4) precipitation, ion exchange chromatography on DEAE-cellulose, affinity chromatography on N-acetyl-D-glucosamine-agarose, and gel filtration by fast protein liquid chromatography on Superdex 75. The lectin exhibited hemagglutinating activity toward trypsinized rabbit erythrocytes but not toward untrypsinized rabbit erythrocytes.

Acetylglucosamine↗

PubMed2003

Purification of castamollin, a novel antifungal protein from Chinese chestnuts.

A novel antifungal protein, designated castamollin, was isolated from Chinese chestnut (Castanea mollisima) seeds with a procedure involving ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-Sepharose and FPLC-gel filtration on Superdex 75. Castamollin possessed a novel N-terminal sequence demonstrating little similarity to N-terminal sequences of Castanea sativa chitinase. Castamollin exhibited a molecular mass of 37kDa in gel filtration and SDS-PAGE. It inhibited the activity of human immunodeficiency virus-1 reverse transcriptase with an IC(50) of 7microM and translation in a cell-free rabbit reticulocyte lysate system with an IC(50) of 2.7microM. Castamollin displayed antifungal activity against Botrytis cinerea, Mycosphaerella arachidicola, Physalospora piricola, and Coprinus comatus but was devoid of lectin activity.

Amino Acid Sequence↗

PubMed2003

Isolation of pisumin, a novel antifungal protein from legumes of the sugar snap pea Pisum sativum var macrocarpon.

An antifungal protein with a novel N-terminal sequence GVGAAYGCFG and a molecular mass of 31 kDa was isolated from the legumes of the sugar snap pea Pisum sativum var. macrocarpon. The protein, designated pisumin, exhibited antifungal activity against Coprinus comatus and Pleurotus ostreatus and much weaker activity against Fusarium oxysporum and Rhizoctonia solani. Pisumin inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC(50) of 6 microM. Pisumin was similar to other leguminous antifungal proteins in that it was adsorbed on Affi-gel blue gel and CM-Sepharose.

Animals↗

PubMed2003

Antioxidant activity of compounds from the medicinal herb Aster tataricus.

A number of compounds were isolated from the medicinal plant Aster tataricus including shionone, epifriedelinol, quercetin, kaempferol, scopoletin, emodin, aurantiamide acetate and 1,7-dihydroxy-6-methyl-anthraquinone. The compounds were compared with regard to their ability in inhibiting hemolysis of rat erythrocytes induced by 2'-2' azobis (2-amidinopropane) dihydrochloride, lipid peroxidation using the FeSO(4)-ascorbic acid system, and generation of superoxide radicals using a phenazine methosulfate-nicotinamide adenine dinucleotide system. The effects on the Fe-bleomycin-induced DNA damage reflected pro-oxidant activity. Quercetin and kaempferol were most potent in inhibiting hemolysis, lipid peroxidation and superoxide radical generation. Scopoletin and emodin were similar to quercetin and kaempferol in inhibiting superoxide radical generation and second to them in inhibiting lipid peroxidation. Aurantiamide acetate exhibited some inhibitory activity toward superoxide radical generation. 1,7-dihydroxy-6-methyl-anthraquinone exerted an inhibitory activity only on superoxide radical generation. Shionone and epifriedelinol did not display any antioxidant activity. Quercetin and kaempferol, but not the remaining compounds, exhibited some pro-oxidant activity.

Animals↗

PubMed2003

Mollisin, an antifungal protein from the chestnut Castanea mollissima.

The isolation of a protein designated mollisin, with an N-terminal sequence manifesting some similarity to thaumatin-like proteins (TLPs), and possessing a molecular mass of 28 kDa which is higher than those of TLPs, is reported herein from the seeds of the chestnut Castanea mollisima. The protein was unadsorbed on DEAE-cellulose, and adsorbed on Affi-gel blue gel and Mono S. Mollisin exhibited a molecular mass of 28 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as well as in gel filtration on Superdex 75 by fast protein liquid chromatography. The protein inhibited mycelial growth in Fusarium oxysporum, Mycosphaerella arachidicola and Physalospora piricola, with an IC (50) of 0.83 microM, 6.48 microM and 9.21 microM, respectively. Mollisin displayed a higher antifungal potency than French bean and kiwi fruit TLPs toward F. oxysporum and M. arachidicola. The antifungal activity of mollisin was unaffected by incubation at 40 degrees C for 10 minutes, underwent a decline after incubation at 60 degrees C, and was completely abolished after treatment at 80 degrees C. Mollisin exhibited a more potent inhibitory activity on HIV-1 reverse transcriptase than kiwi fruit TLP.

Amino Acid Sequence↗

PubMed2003

Contamination of ribosome inactivating proteins with ribonucleases, separated by affinity chromatography on red sepharose.

Three preparations of type 1 ribosome inactivating proteins (RIPs), namely, agrostin, saporin, and luffin, were subjected to affinity chromatography on Red Sepharose and eluted with a linear concentration gradient of NaCl in 10 mM Tris-HCl buffer (pH 7.4). The eluate was assayed for ability to inhibit translation in a cell-free rabbit reticulocyte lysate system which measures RIP activity, and for ability to hydrolyze yeast transfer RNA which measures RNase activity. It was found that, in all three RIP preparations, the peak of RIP activity, which coincided with the peak of absorbance at 280 nm, was eluted earlier than the peak of RNase activity. It appears that RNase is a possible contaminant of ribosome inactivating protein preparations and that this contamination can be minimized by using Red Sepharose.

Animals↗

PubMed2003

Purification of glysojanin, an antifungal protein, from the black soybean Glycine soja.

A monomeric protein, with a molecular mass of 25 kDa and an N-terminal sequence resembling a segment of chitin synthase, was isolated from the seeds of the black soybean Glycine soja. The protein, designated glysojanin, demonstrated potent antifungal activity against the fungi Fusarium oxysporum and Mycosphaerella arachidicola. It inhibited HIV-1 reverse transcriptase with an IC50 of 47 micromol/L, [methyl-3H]thymidine incorporation by mouse spleen cells with an IC50 of 175 micromol/L, and translation in the rabbit reticulocyte lysate with an IC50 of 20 micromol/L. Glysojanin was purified using a procedure that involved ion-exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion-exchange chromatography by fast protein liquid chromatography on Mono S, and gel filtration by fast protein liquid chromatography on Superdex 75.

Amino Acid Sequence↗

PubMed2003

Fabin, a novel calcyon-like and glucanase-like protein with mitogenic, antifungal and translation-inhibitory activities from broad beans.

A protein with an N-terminal sequence displaying similarities to N-terminal sequences of human calcyon and barley endo-1,4-glucanase, and to C-terminal sequences of human translation initiation factor 4 gamma and yeast superkiller viralicidic activity, was isolated from the broad bean Vicia faba. The protein, termed fabin, has a molecular mass of 34 kDa in SDS-polyacrylamide gel electrophoresis. Antifungal activity of the protein was observed against several fungal species including Rhizoctonia solani, Botrytis cinerea, Fusarium oxysporum and Mycosphaerella arachidicola. Fabin inhibits HIV-1 reverse transcriptase with an IC50 of 34 microM and translation in a rabbit reticulocyte lysate with an IC50 of 2.4 microM. At a concentration of about 1.5 microM fabin is able to elicit a 9-fold increase in the mitogenic response of murine splenocytes.

Amino Acid Sequence↗

PubMed2002

Isolation of a novel peroxidase from French bean legumes and first demonstration of antifungal activity of a non-milk peroxidase.

A novel antifungal protein with its N-terminal sequence bearing similarity to the C-terminal sequences of peroxidases was isolated from French bean legumes. The protein, which possessed a molecular weight of 37 kDa, was adsorbed on Affi-gel blue gel and CM-Sepharose. The protein exhibited peroxidase activity with a Km of 58 microM and a Vmax of 3.36 U/nmol. Optimal peroxidase activity was found at 22 degrees C and pH 4. It exerted antifungal activity against a variety of fungal species including Coprinus comatus, Mycosphaerella arachidicola, Fusarium oxysporum and Botrytis cinerea. It inhibited the activities of alpha-glucosidase and beta-glucosidase but was without any inhibitory effect on HIV-1 reverse transcriptase.

Amino Acid Sequence↗

PubMed2002

A xylanase from roots of sanchi ginseng (Panax notoginseng) with inhibitory effects on human immunodeficiency virus-1 reverse transcriptase.

A xylanase with a molecular weight of 15 kDa, which is lower than those of previously reported xylanases, was isolated from the roots of the medicinal herb Panax notoginseng. The xylanase exhibits a temperature optimum of 50 degrees C and a pH optimum between 5 and 6. It inhibits HIV-1 reverse transcriptase with an IC(50) of 10 microM, but does not affect translation in a cell-free rabbit reticulocyte system when tested up to 70 microM. The enzyme is adsorbed on CM-cellulose, Affi-gel blue gel and Mono S. Previously xylanases have been isolated from seeds and not from roots, and have not been demonstrated to inhibit HIV-1 reverse transcriptase.

Chromatography↗

PubMed2002

A novel and potent ribonuclease from fruiting bodies of the mushroom Pleurotus pulmonarius.

A ribonuclease (RNase), with an N-terminal sequence different from those of ribonucleases from the mushrooms Irpex lacteus, Lentinus edodes, Pleurotus ostreatus, Pleurotus tuber-regium, and Volvariella volvacea, was purified from fruiting bodies of the edible mushroom Pleurotus pulmonarius. The N-terminal sequence of P. pulmonarius RNase manifested homology to a portion of the sequences of ribosome inactivating protein abrin-b, abrin-c, and abrin-d, and Bacillus subtilis transcriptional regulator. The ribonuclease was adsorbed on Affi-gel blue gel, CM-Sepharose, and Mono S. It displayed a molecular mass of 14.4 kDa in both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration on Superdex 75. The ribonuclease exhibited an activity of 25 114 U/mg on yeast tRNA. The highest ribonucleolytic activity was demonstrated toward poly C, followed by poly A, and then by poly G. There was no activity toward poly U. The optimal pH for its activity was 7 and the optimal temperature was 55 degrees C. It inhibited cell-free translation in a rabbit reticulocyte lysate with an IC50 of 0.33 nM.

Amino Acid Sequence↗

PubMed2002

Isolation of a new cyclophilin-like protein from chickpeas with mitogenic, antifungal and anti-HIV-1 reverse transcriptase activities.

A protein designated chickpea cyclophilin-like antifungal protein (CLAP) was isolated from seeds of the chickpea (Cicer arietinum). Chickpea CLAP was characterized by a molecular weight of 18 kDa and an N-terminal sequence homologous to cyclophilins. The protein was isolated with a procedure involving affinity chromatography on Affi-gel blue gel and ion exchange chromatography on CM-Sepharose. In addition to an inhibitory effect on the growth of fungi including Rhizoctonia solani, Mycosphaerella arachidicola and Botrytis cinerea, the protein was capable of inhibiting human immunodeficiency virus-1 reverse transcriptase. Chickpea CLAP did not possess lectin and ribonuclease activities but it weakly inhibited translation in a rabbit reticulocyte lysate system. The protein stimulated 3H-thymidine incorporation by mouse splenocytes.

Amino Acid Sequence↗

PubMed2002

A new antifungal protein and a chitinase with prominent macrophage-stimulating activity from seeds of Phaseolus vulgaris cv. pinto.

From the seeds of the pinto bean (Phaseolus vulgaris cv. pinto), a chitinase and a novel antifungal protein, both with the ability of markedly augmenting nitrite production by murine peritoneal macrophages, were isolated. The antifungal proteins, designated phasein A and phasein B, exhibited molecular weights of 28 and 32 kDa, respectively. Phaseins A and B were adsorbed on Affi-gel blue gel and CM-Sepharose and were eluted as adjacent peaks from CM-Sepharose. Phasein A demonstrated potent antifungal activity toward Fusarium oxysporum and Physalospora piricola. Phasein B was more potent than phasein A toward P. piricola but less potent than phasein A toward F. oxysporum and Rhizoctonia solani. Both antifungal proteins inhibited the activity of HIV-1 reverse transcriptase and translation in a rabbit reticulocyte lysate system, with phasein B being more potent. Nitrite production by mouse macrophages was greatly boosted in the presence of both phaseins A and B, although the effect of phasein A was more prominent. The bioactivities of phaseins were in general potent compared with those of other antifungal proteins.

Antifungal Agents↗

PubMed2002

Isolation of a novel agglutinin with complex carbohydrate binding specificity from fresh fruiting bodies of the edible mushroom Lyophyllum shimeiji.

A hemagglutinin, with a molecular weight of 30,000 and expressing hemagglutinating activity which could not be inhibited by simple sugars and glycoproteins, was isolated from fresh fruiting bodies of the edible mushroom Lyophyllum shimeiji. The protein was adsorbed on CM-Sepharose even in 20 mM ammonium acetate (pH 5.5) containing 1 M NaCl and was desorbed by 20 mM ammonium bicarbonate (pH 9). The hemagglutinating activity was subsequently adsorbed on Mono S in 20 mM ammonium acetate (pH 5.5) and was desorbed by a linear gradient of 0.2-0.5 M NaCl in ammonium acetate buffer. The hemagglutinin exhibited a novel N-terminal sequence not found in any lectin and hemagglutinin reported so far. It was devoid of antifungal activity.

Acetates↗

PubMed2002

Inhibitory effects of antifungal proteins on human immunodeficiency virus type 1 reverse transcriptase, protease and integrase.

A variety of antifungal proteins were isolated from seeds of leguminous plants including French bean, cowpea, field bean, mung bean, peanut and red kidney bean. They were assayed for ability to inhibit human immunodeficiency virus type I (HIV-1) reverse transcriptase, protease and integrase, enzymes essential to the life cycle of HIV-1 . It was found that the cowpea beta-antifungal protein had a high potency in inhibiting HIV-1 protease and HIV-1 integrase. Cowpea alpha-antifungal protein was potent in inhibiting HIV-1 reverse transcriptase and HIV-1 integrase. Peanut antifungal protein was characterized by a high inhibitory activity against HIV-1 integrase and an intermediate potency in inhibiting HIV- I reverse transcriptase and HIV- I protease. French bean thaumatin-like protein expressed low HIV- I protease inhibitory activity and red kidney bean lectin inhibited HIV- I integrase by only a very small extent. Antifungal proteins from the field bean and mung bean had an intermediate potency in inhibitory HIV-1 protease and integrase. However, mung bean antifungal protein was not capable of inhibiting HIV-1 reverse transcriptase. The results indicate that nearly all leguminous antifungal proteins examined were able to inhibit HIV-1 reverse transcriptase, protease and integrase to some extent.

Amino Acid Sequence↗

PubMed2002

Isolation of a new heterodimeric lectin with mitogenic activity from fruiting bodies of the mushroom Agrocybe cylindracea.

From the dried fruiting bodies of the mushroom Agrocybe cylindracea a heterodimeric lectin with a molecular weight of 31.5 kDa and displaying high hemagglutinating activity was isolated. The molecular weights of its subunits were 16.1 kDa and 15.3 kDa respectively. The larger and the smaller subunits resembled Agaricus bisporus lectin and fungal immunomodulatory protein from Volvariella volvacea respectively in N-terminal sequence. The lectin was adsorbed on DEAE-cellulose in 10 mM Tris-HCl buffer (pH 7.4) and was eluted by the same buffer containing 150 mM NaCl. It was adsorbed on SP-Sepharose in 10 mM NH4OAc (pH 4.5) and eluted by approximately 0.19 M NaCl in the same buffer. The lectin was obtained in a purified form after the mushroom extract had been subjected to (NH4)2SO4 precipitation and the two aforementioned ion exchange chromatographic steps. The lectin exhibited potent mitogenic activity toward mouse splenocytes. The hemagglutinating activity of the lectin was inhibited by lactose, sialic acid and inulin.

Amino Acid Sequence↗

PubMed2002

Purification of angularin, a novel antifungal peptide from adzuki beans.

An antifungal peptide was isolated from the adzuki bean with a procedure involving affinity chromatography on Affi-gel blue gel and ion exchange chromatography on CM-Sepharose. The protein designated angularin was adsorbed on both types of chromatographic media and possessed a molecular weight of 8 kDa. Angularin exhibited antifungal activity against a variety of fungal species including Mycospharella arachidiocola and Botrytis cinerea. It inhibited mycelial growth in B. cinerea with an IC50 of 14.3 microM. Fusarium oxysporum and Rhizoctonia solani were not inhibited. Angularin demonstrated inhibitory activity on translation in the rabbit reticulocyte lysate system (IC50 = 8.0 microM) but did not affect proliferation of splenocytes. The activity of HIV-1 reverse transcriptase was inhibited in the presence of angularin. Its N-terminal sequence was GEPGQKE.

Animals↗