Bioactive metabolites from <Emphasis Type="Italic">Penicillium</Emphasis> sp., an endophytic fungus residing in <Emphasis Type="Italic">Hopea hainanensis</Emphasis>

The metabolites of endophytic fungus Penicillium sp. from the leaf of Hopea hainanensis were reported for the first time. By bioassay-guided fractionation, the EtOAc extract of a solid-matrix steady culture of this fungus afforded six compounds, which were identified through a combination of spectral and chemical methods (IR, MS, ¹H- and ¹³C-NMR) to be monomethylsulochrin (1), rhizoctonic acid (2), asperfumoid (3), physcion (4), 7,8-dimethyl-iso-alloxazine (5) and 3,5-dichloro-p-anisic acid (6). Compounds 2, 3 and 6 were obtained from Penicillium sp. for the first time. All of the six isolates were subjected to in vitro bioactive assays including antifungal action against three human pathogenic fungi Candida albicans, Trichophyton rubrum and Aspergillus niger and cytotoxic activity against the human nasopharyngeal epidermoid tumor KB cell line and human liver cancer HepG2 cell line. As a result, compounds 2–4 and 6 inhibited the growth of C. albicans with MICs of 40.0, 20.0, 50.0 and 15.0 μg/ml, respectively and the compound 6 showed growth inhibition against A. niger with MICs of 40.0 μg/ml. In addition, compounds 1–3 and 6 exhibited cytotoxic activity against KB cell line with IC₅₀ value of 30.0, 20.0, 20.0, 5.0 μg/ml, respectively and against HepG2 cell line with IC₅₀ value of 30.0, 25.0, 15.0, 10.0 μg/ml, respectively.     

Molecular Chaperone-Assisted Production of Human α-1,4-<Emphasis Type="Italic">N</Emphasis>-Acetylglucosaminyltransferase in Silkworm Larvae Using Recombinant BmNPV Bacmids

In this study, human α-1,4-N-acetylglucosaminyltransferase (α4GnT) fused with GFP_uv (GFP_uv-α4GnT) was expressed using both a transformed cell system and silkworm larvae. A Tn-pXgp-GFP_uv-α4GnT cell line, isolated after expression vector transfection, produced 106 mU/ml of α4GnT activity in suspension culture. When Bombyx mori nucleopolyhedrovirus containing a GFP_uv-α4GnT fusion gene (BmNPV-CP ⁻/GFP_uv-α4GnT) bacmid was injected into silkworm larvae, α4GnT activity in larval hemolymph was 352 mU/ml, which was 3.3-fold higher than that of the Tn-pXgp-GFP_uv-α4GnT cell line. With human calnexin (CNX) or human immunoglobulin heavy chain-binding protein (BiP, GRP78) coexpressed under the control of the ie-2 promoter, α4GnT activity in larval hemolymph increased by 1.4–2.0-fold. Moreover, when BmNPV-CP ⁻/GFP_uv-α4GnT bacmid injection was delayed for 3 h after BmNPV-CP ⁻/CNX injection, the α4GnT activity increased significantly to 922 mU/ml, which was 8.7-fold higher than that of the Tn-pXgp-GFP_uv-α4GnT cell line. Molecular chaperone assisted-expression in silkworm larvae using the BmNPV bacmid is a promising tool for recombinant protein production. This system could lead to large-scale production of more complex recombinant proteins.     

Effect of new rotenoid glycoside from the fruits of Amorpha fruticosa LINNE on the growth of human immune cells

A new compound, rotenoid isoflavone glycoside named, 6′-O-β-d-glucopyranosyl-12a-hydroxydalpanol was isolated from the methanolic (MeOH) fruit extract of Amorpha fruticosa LINNE by means of multi-stage column chromatography. Immuno-modulatory activities of this new glycoside were compared with the partitioned fractions of Amorpha fruticosa LINNE. Both of the fractions and purified single compound showed a 19% relatively low cytotoxicity at a maximum concentration of 1.0 g/L in a cultivated normal human lung cell line (HEL299). The purified single compound showed less cytotoxicity than the crude extracts, possibly because residual toxicants were eliminated during purification processes. Cell growth of human T cells was increased by about 15% by adding 0.5 g/L of the fractions compared to the control. Specific production rates of interleukin-6 (IL-6) and tumor necrosis factor (TNF-α) from T cell were higher as 1.16 × 10⁻⁴ and 1.86 × 10⁻⁴ pg/cell, respectively, in the purified compound, compared to 1.38 × 10⁻⁴ and 2.22 × 10⁻⁴ pg/cell, respectively, by adding 0.5 g/L of the dichloromethane fraction. Natural killer cell-92MI (NK-92MI) growth supplemented with the supernatant of human T cell was up to 19% higher with the dichloromethane fraction compared with a new single compound at a concentration of 0.5 g/L. Overall, the dichloromethane fraction showed relatively higher immuno-modulatory activities compared with a new single compound, probably due to the synergic effect given by other substances existing in the fractions.     

Regulation of intracellular calcium release and PP1α in a mechanism for 4-hydroxytamoxifen-induced cytotoxicity

Treatment with tamoxifen, or its metabolite 4-hydroxytamoxifen (4OHT), has cytostatic and cytotoxic effects on breast cancer cells in vivo and in culture. Although the effectiveness of 4OHT as an anti-breast cancer agent is due to its action as an estrogen receptor-alpha (ERα) antagonist, evidences show that 4OHT is also cytotoxic for ERα-negative breast cancer cells and can be effective therapy against tumors that lack estrogen receptors. These findings underscore 4OHT signaling complexities and belie the most basic understandings of 4OHT action and resistance. Here, we have investigated the effects of 4OHT on Ca²⁺ homeostasis and cell death in breast cancer cells in culture. Measurement of Ca²⁺ signaling in breast cancer cells showed that 4OHT treatment altered Ca²⁺ homeostasis and was cytotoxic for both an ERα+ and an ERα- cell line, MCF-7 and MDA-MB-231, respectively. Further investigation lead us to the novel discovery that 4OHT-induced increase of ATP-dependent Ca²⁺ release from the endoplasmic reticulum correlated with 4OHT-induced upregulation of protein phosphatase 1α (PP1α) and the inositol 1,4,5-trisphosphate receptor (IP3R). Blocking 4OHT-induced PP1α upregulation by siRNA strategy reduced the effects of 4OHT on both Ca²⁺ signaling and cytotoxicity. Results from these investigations strongly suggest a role for PP1α upregulation in a mechanism for 4OHT-induced changes to Ca²⁺ signaling that ultimately contribute to the cytotoxic effects of 4OHT. Aliccia Bollig, Liping Xu- contributed equally to this work     

Antiproliferative activity of chloroformic extract of Persian Shallot, Allium hirtifolium, on tumor cell lines

Allium hirtifolim (Persian Shallot) belongs to Allium genus (Alliaceae family). We investigated the in vitro effects of chloroformic extract of A. hirtifolium and its Allicin on the proliferation of HeLa (cervical cancer), MCF7 (human, caucasion, breast, adenocarcinoma) and L929 (mouse, C3H/An, connective) cell lines. Our results showed that components of A. hirtifolium might inhibit proliferation of tumor cell lines. This inhibition in HeLa and MCF-7 cells was dose-dependent. The presence of Allicin was evaluated by TLC method in bulbs and the extract of A. hirtifolium was analyzed by HPLC. MTT test was performed 24, 48 and 72 h after cell culture. A significant decrease in cell lines was observed in HeLa and MCF-7 as compared to L929 cell lines. DNA fragmentation analysis revealed a large number of apoptotic cells in treated HeLa and MCF-7 cell groups, but no effects in L929 cells. Therefore A. hirtifolium might be a candidate for tumor suppression.     

Studies on the production of conjugated linoleic acid from linoleic and vaccenic acids by mixed rumen protozoa

The conversion of β-myrcene to the furanoid flavour compound perillene by Pleurotus ostreatus was investigated using trideutero β-myrcene, trideutero α-(Z)-acaridiol and non-labeled 1,2- and 3,10-epoxy-β-myrcene, α,α-acarilactol, and perillene as substrates. Myrcene diols were formed from the cleavage of myrcene epoxides, but only α-(Z)-acaridiol, a 1,4-butanediol derivative most likely generated through a base-catalysed epoxide opening, was a suitable precursor of perillene. Once formed, this key intermediate was rapidly oxidised and the resulting cyclic lactol was dehydrated to yield perillene. Bioconversion of the supplemented perillene to α,α-acariolide indicated that perillene was another intermediate of the pathway and prone to further oxidative degradation. The data suggest that the fungus converted the cytotoxic β-myrcene in its environment into a metabolically useable carbon source along this route.     

Cytotoxic activity of some lichen extracts on murine and human cancer cell lines

Eight lichens were extracted successively with n-hexane, diethyl ether and methanol using a Soxhlet process. The cytotoxic activity of the 24 lichen extracts was evaluated in vitro using two murine (the L1210: lymphocytic leukaemia, and the 3LL: Lewis lung carcinoma) and four human (the K-562: chronic myelogenous leukaemia, the U251: glioblastoma, the DU145: prostate carcinoma, and the MCF7: breast adenocarcinoma) cancer cell lines and non-cancerous cells, the Vero cell line (African green monkey kidney cell line). The MTT assay revealed significant cytotoxicity (IC50 < or = 20 microg/ml) on one of the tested cancer cell lines for at least one extract of each lichen species. Some extracts of Cladonia convoluta, Cladonia rangiformis, Parmelia caperata, Platismatia glauca and Ramalina cuspidata demonstrated interesting activities particularly on human cancer cell lines as good selectivity indices were recorded (SI > 3).     

Growth inhibitory activity of extracts and compounds from Cimicifuga species on human breast cancer cells

The purpose of this report is to explore the growth inhibitory effect of extracts and compounds from black cohosh and related Cimicifuga species on human breast cancer cells and to determine the nature of the active components. Black cohosh fractions enriched for triterpene glycosides and purified components from black cohosh and related Asian species were tested for growth inhibition of the ER⁻ Her2 overexpressing human breast cancer cell line MDA-MB-453. Growth inhibitory activity was assayed using the Coulter Counter, MTT and colony formation assays.Results suggested that the growth inhibitory activity of black cohosh extracts appears to be related to their triterpene glycoside composition. The most potent Cimicifuga component tested was 25-acetyl-7,8-didehydrocimigenol 3-O-β-d-xylopyranoside, which has an acetyl group at position C-25. It had an IC₅₀ of 3.2 μg/ml (5 μM) compared to 7.2 μg/ml (12.1 μM) for the parent compound 7,8-didehydrocimigenol 3-O-β-d-xylopyranoside. Thus, the acetyl group at position C-25 enhances growth inhibitory activity.The purified triterpene glycoside actein (β-d-xylopyranoside), with an IC₅₀ equal to 5.7 μg/ml (8.4 μM), exhibited activity comparable to cimigenol 3-O-β-d-xyloside. MCF7 (ER⁺Her2 low) cells transfected for Her2 are more sensitive than the parental MCF7 cells to the growth inhibitory effects of actein from black cohosh, indicating that Her2 plays a role in the action of actein. The effect of actein on Her2 overexpressing MDA-MB-453 and MCF7 (ER⁺Her2 low) human breast cancer cells was examined by fluorescent microscopy. Treatment with actein altered the distribution of actin filaments and induced apoptosis in these cells.These findings, coupled with our previous evidence that treatment with the triterpene glycoside actein induced a stress response and apoptosis in human breast cancer cells, suggest that compounds from Cimicifuga species may be useful in the prevention and treatment of human breast cancer.     

Signal peptide of Arabinosidase enhances secretion of interferon-α2b protein by <Emphasis Type="Italic">Bifidobacteria longum</Emphasis>

Bifidobacteria can potentially be used for gene therapy. Here, we reported that 65% of the total hIFN-α2b produced from Bifidobacteria longum transformed with pBAD-SPIFN plasmids encoding a fusion protein of the arabinosidase signal peptide and human IFN-α2b (hIFN-α2b), was secreted. For B. longum transformed with pBAD-IFN plasmids (hIFN-α2b without the signal peptide), only 15% of the total IFN-α2b was secreted and western blotting and N-terminal amino-acid sequence analysis revealed cleavage of the arabinosidase signal peptide from the secreted hIFN-α2b. Moreover, the active level of the secreted hIFN-α2b in the supernatant of B. longum transformed with pBAD-SPIFN plasmids was over 1,000 IU/ml commercial rhIFN-α2b. Hence, the arabinosidase signal peptide can enhance the secretion efficiency of IFN-α2b from B. longum. Q. Deng, W. Zeng and Z. Yu contributed equally to this work.     

Assessment of antifungal effects of a novel compound from <Emphasis Type="Italic">Burkholderia cepacia</Emphasis> against <Emphasis Type="Italic">Fusarium solani</Emphasis> by fluorescent staining

A novel compound CF66I produced by Burkholeria cepacia was investigated for its antifungal effects against Fusarium solani by three different fluorescent dyes. Dual staining with propidium iodide (PI) and fluorescein diacetate (FDA) demonstrated high doses of CF66I (120.0 μg ml⁻¹) killed the fungi by acting primarily on the cell membrane. However, at fungistatic concentration (20.0 μg ml⁻¹) of this compound, microscopic observations revealed swelling hyphae with abnormal chitin deposition, as determined by Calcofluor white (CFW) staining, which was indicative of the alterations in cell wall structure. In addition, inhibition of intracellular esterases activity was observed. These results led us to conclude that low doses of CF66I probably inhibited the fungal growth by interfering with the cell metabolic pathways.     

Synthesis of (Z)-3-(arylamino)-1-(3-phenylimidazo[1,5-a]pyridin-1-yl)prop-2-en-1-ones as potential cytotoxic agents

The new derivatives based on (Z)-3-(arylamino)-1-(3-phenylimidazo[1,5-a]pyridin-1-yl)prop-2-en-1-one scaffold was synthesized and evaluated for their in vitro cytotoxic potential against a panel of cancer cell lines, viz., A549 (human lung cancer), HCT-116 (human colorectal cancer), B16F10 (murine melanoma cancer), BT-474 (human breast cancer), and MDA-MB-231 (human triple-negative breast cancer). Among them, many of the synthesized compounds exhibited promising cytotoxic potential against the panel of tested cancer cell lines with IC₅₀ <30 µM. Based on the preliminary screening results, the structure-activity relationship (SAR) of the compounds was established. Among the synthesized compounds, 15i displayed a potential anti-proliferative activity against HCT-116 cancer cell line with an IC₅₀ value of 1.21 ± 0.14 µM. Flow cytometric analysis revealed that compound 15i arrested the G0/G1 phase of the cell cycle. Moreover, increased reactive oxygen species (ROS) generation, clonogenic assay, acridine orange staining, DAPI nuclear staining, measurement of mitochondrial membrane potential (ΔΨm), and annexin V-FITC assays revealed that compound 15i promoted cell death through apoptosis.     

Effect of some essential oils on mycelial growth of <Emphasis Type="Italic">Penicillium digitatum</Emphasis> Sacc.

The antifungal action of four essential oils of Foeniculum vulgare (fennel), Thymus vulgaris (thyme), Eugenia caryophyllata (Clove) and Salvia officinalis (sage) was tested in vitro against Penicillium digitatum Sacc. Direct contact and vapour phase were used to test the antifungal activity of these essential oils against P. digitatum that is responsible for green mould rot of citrus fruits. The vapour phase and direct contact of clove and thyme essential oils exhibited the strongest toxicity and totally inhibited the mycelial growth of the test fungus. Thyme and clove essential oils completely inhibited P. digitatum growth either when added into the medium 600 μl l⁻¹ or by their volatiles with 24 μl per 8 cm diameter Petri dish. In in vitro mycelial growth assay showed fungistatic and fungicidal activity by clove and thyme essential oils. Sage and fennel oils did not show any inhibitory activity on this fungus. Scanning electron microscopy (SEM) was done to study the mode of action of clove oil in P. digitatum and it was observed that treatment with the oil leads to large alterations in hyphal morphology.     

Antiproliferative activity of sulfated polysaccharide isolated from an enzymatic digest of Ecklonia cava on the U-937 cell line

A sulfated polysaccharide purified from a brown alga Ecklonia cava, having high anticoagulant activity was investigated for its antiproliferative effect on murine colon carcinoma (CT-26), human leukemic monocyte lymphoma (U-937), human promyelocytic leukemia (HL-60), and mouse melanoma (B-16) cell lines. The sulfated polysaccharide isolated and purified from an enzymatic extract of E. cava had a good selective tumor cell growth inhibition effect; its effect on HL-60 and U-937 was especially promising. The IC₅₀ value for the sulfated polysaccharide from E. cava (ECSP) on U-937 was 43.9 μg mL⁻¹. The presence of the sample in the cell culture media stimulated the induction of apoptosis, revealed by nuclear staining with Hoechst 33342. The apoptosis induction was confirmed by the cell cycle analysis, while pronounced sub-G1 phase arrests of 9.5% and 13.8% were also clearly observed when the cells were treated at 15 and 30 μg mL⁻¹ of ECSP in the U-937 cell line, respectively. After a 24-h incubation period, ECSP dose-dependently enhanced the DNA fragmentation on the U-937 cell line as observed in the agarose gel electrophoresis assay. To rule out the action mechanism of ECSP for its anticancer activity, some western blot analyses were conducted with several antibodies (caspase-7, caspase-8, Bax, Bcl-xL, and PARP) and ECSP had a clear effect on the caspase -7 and 8 which cleave protein substrates, including PARP, an inducer of apoptosis responsible for DNA cleavage. Moreover, ECSP controlled the cellular transmembrane molecules like Bax and Bcl-xL. Taken together, the above results demonstrate that the apoptosis for antiproliferative effect of ECSP was clearly induced on U-937 cells.     

喙尾琵琶甲肠道来源链霉菌(Streptomyces sp.)BPA71次级代谢产物的分离鉴定及其生物活性评价

【背景】昆虫是世界上种类最多、肠道菌群资源最丰富且多样的动物类群之一。昆虫肠道微生物具有产生活性次级代谢产物的能力,是活性天然产物的重要来源。【目的】研究药用昆虫喙尾琵琶甲(Blaps rynchopetera)成虫肠道来源链霉菌(Streptomyces sp.) BPA71的次级代谢产物及其生物活性。【方法】利用正相硅胶柱色谱、葡聚糖凝胶Sephadex LH-20柱色谱等方法分离纯化该菌株的发酵粗提物,采用牛津杯法进行抗菌活性追踪,确定抗菌活性部位,通过ESI-MS、NMR等波谱数据分析对化合物结构进行鉴定,采用微量肉汤稀释法测定最低抑菌浓度(minimal inhibitory concentration, MIC),采用MTS法测定抗肿瘤活性。【结果】从Streptomyces sp. BPA71的固体发酵提取物中共分离得到4个已知化合物,通过对比核磁数据确定为糠酸甲酯(1)、吡咯甲酰胺A (2)、吡咯甲酰胺B (3)和吲哚-3-乙酸甲酯(4)。抗菌活性结果显示化合物2具有广谱抗菌活性。此外,化合物2对宫颈癌细胞HeLa、肺癌细胞A549、肝癌细胞SMMC-7721、乳腺癌细胞MDA-MB-231和结肠癌细胞SW480这5株肿瘤细胞均有明显的抑制活性。【结论】喙尾琵琶甲肠道来源Streptomyces sp. BPA71可产生丰富的生物活性物质,该研究结果为进一步挖掘喙尾琵琶甲肠道链霉菌的活性天然产物奠定了基础,同时丰富了人们对喙尾琵琶甲肠道微生物的认识。     

Selective removal of anti-α-Gal antibodies from human serum by using synthetic α-Gal epitope on a core-shell type resin

A novel α-Gal resin was chemo-enzymatically synthesized for the efficient adsorption of anti-α-Gal antibodies in human serum for xenotransplantation. To covalently conjugate a hexanoate linker with lactose and N-acetylglucosamine, both acceptor sugars were acetylated and brominated. Then, α-and β-galactoses were sequentially added to the linker-containing saccharides at their non-reducing ends by using recombinant α-(1,3)-and β-(1,4)-galactosyltransferases from E. coli. Finally, the synthesized α-Gal derivatives were immobilized on HiCore, a core-shell type resin, that was functionalized with amino groups on the shell region, as a packing material on-column. Using this method we were able to demonstrate that the α-Gal HiCore resin had a reduced level of non-specific protein adsorption compared with the commercially available polystyrene supports, TentaGel, and agarose-based supports, when Lectin BS-I was used as the model binding protein. Furthermore, the α-Gal HiCore resin was more efficient at eliminating anti-α-Gal IgGs from the total human IgGs through immunoadsorption than the other two α-Gal resins, α-Gal TentaGel and α-Gal agarose. The α-Gal HiCore resin developed in this study can be utilized in a wide range of applications including ex vivo immunoadsorption and as a quantitative assay of anti-Gal antibody in human sera.     

Cytotoxin production by a merineLyngbya strain (cyanobacterium) in a large-scale laboratory bioreactor

A cytotoxic compound was produced by the marine cyanobacteriumLyngbya sp. Pearl strain in large laboratory-scale batch cultures. Adsorption and fractionation of methanol extracts with reverse phase (C-18) cartridges provided a rapid method for removal of bioassay interference from salts, biopolymers and pigments and concentration of the cytotoxic principles. Cytotoxicity to the murine leukemia cell line P-388 was produced in two cycles coinciding with the initiation of exponential growth and again during the late exponential growth phase. Antiviral activity against influenza virus PR8 was found in extracts prepared from early exponential growth phase cells but antiviral activity was not detected in extracts of mid-log or late-log growth phase cells. These differences in bioactivity suggests that the cytotoxic principles produced during early and late exponential growth may be different compounds. Cytotoxicity assays using murine P-388 leukemia indicates that the semi-pure compound has an IC₅₀ of < 0.25 μg ml⁻¹ to this cell line. P-388 cytotoxicity in cell extracts increased during the late exponential growth phase and the specific yield was estimated at approximately 0.14 mg g⁻¹ (dry cells).     

Mutagenic and Genotoxic Effects of <Emphasis Type="Italic">cis</Emphasis>-(Dichloro)tetraammineruthenium(III) Chloride on Human Peripheral Blood Lymphocytes

Chemotherapeutic agents play an important role in cancer treatment mostly due their systemic action on human organism allowing access to liquid tumors and even metastases. Among these drugs, ruthenium compounds have been showing promising results to treat tumors and represent an important development of new antitumor therapy. This study presents the evaluation of cis-(dichloro)tetraammineruthenium(III) chloride, cis-[RuCl₂(NH₃)₄]Cl, genotoxic effects using human peripheral blood lymphocytes cultured in vitro. Mitotic index (MI), chromosome aberrations (CA), and DNA damage using the comet assay were analyzed. MI in human peripheral blood lymphocyte cultures treated with 1, 10, 100, and 1,000 μg mL⁻¹ cis-[RuCl₂(NH₃)₄]Cl were 5.9%, 4.6%, 3.9%, and 0%, respectively. Doxorubicin chloridate was used as the positive control. CA derived from 1, 10, and 100 μg mL⁻¹ concentrations were defined as spontaneous when compared with the negative control, and at the concentration of 1,000 μg mL⁻¹, the cell cycle was inhibited (IM = 0%). Results obtained for the comet assay using cis-[RuCl₂(NH₃)₄]Cl suggest that this compound has no genotoxic activity against cultured human peripheral blood lymphocytes.     

Effect of aPMR1 disruption on the processing of heterologous glycoproteins secreted in the yeastSaccharomyces cerevisiae

TheSaccharomyces cerevisiae PMR1 gene encodes a Ca²⁺-ATPase localized in the Golgi. We have investigated the effects ofPMR1 disruption inS. cerevisiae on the glycosylation and secretion of three heterologous glycoproteins, human α₁-antitrypsin (α₁-AT), human antithrombin III (ATHIII), andAspergillus niger glucose oxidase (GOD). Thepmr1 null mutant strain secreted larger amounts of ATHIII and GOD proteins per a unit cell mass than the wild type strain. Despite a lower growth rate of thepmr1 mutant, two-fold higher level of human ATHIII was detected in the culture supernatant from thepmr1 mutant compared to that of the wild-type strain. Thepmr1 mutant strain secreted α₁-AT and the GOD proteins mostly as core-glycosylated forms, in contrast to the hyperglycosylated proteins secreted in the wild-type strain. Furthermore, the core-glycosylated forms secreted in thepmr1 mutant migrated slightly faster on SDS-PAGE than those secreted in themnn9 deletion mutant and the wild type strains. Analysis of the recombinant GOD with anti-α1,3-mannose antibody revealed that GOD secreted in thepmr1 mutant did not have terminal α1,3-linked mannoses unlike those secreted in themnn9 mutant and the wild type strains. The present results indicate that thepmr1 mutant, with the super-secretion phenotype, is useful as a host system to produce recombinant glycoproteins lacking high-mannose outer chains.     

Three inhibitor types from wheat endosperm are differentially active against α-amylases of Lepidoptera pests

Crude α-amylase preparations from seven Lepidoptera pests were susceptible to inhibition by salt-soluble proteins of bread wheat (Triticum aestivum L.) endosperm. Protein fractions that corresponded to tetrameric, dimeric, and monomeric wheat α-amylase inhibitors, were decreasingly effective against the insect α-amylase activity. To further confirm these results, purified inhibitors were tested against an α-amylase preparation fromEphestia kuehniella (Zeller). This preparation showed decreased activity when increasing amounts of an heterotetrameric inhibitor (reconstituted from its isolated subunits WTAI-CM2, -CM3 and -CM16) were assayed. Activity was only partially inhibited by homodimeric (WDAI-1, synonym 0.53; WDAI-2, synonym 0.19) and monomeric (WMAI-1, synonym 0.28) inhibitors.