Bioactive polyphenols in leaves, stems, and berries of Saskatoon (Amelanchier alnifolia Nutt.) cultivars

The Saskatoon berry is currently cultivated in many parts of the world for its suitability for various food products and due to its high content of nutrients and polyphenols. To determine the phytochemical profile of a Saskatoon plant, polyphenols from leaves, stems, and berries were screened from four cultivars grown in Finland using HPLC-DAD and HPLC-ESI/MS. The phenolic composition and concentrations varied among plant parts and cultivars. The main berry components were cyanidin-based anthocyanins (63% of the phenols), quercetin-derived flavonol glycosides, and hydroxycinnamic acids. The total anthocyanin content varied between 258.7 and 517.9 mg/100 fresh weight among cultivars. Protocatechuic acid was found for the first time in Saskatoon berries. The leaves consisted of quercetin- and kaempferol-derived glycosides (41% of the phenols), hydroxycinnamic acids (36%), catechins, and some neolignans. Quercetin 3-galactoside and 3-glucoside, (-)-epicatechin, and chlorogenic acid were the main phenolics in the leaves of all cultivars. The stem components were flavanone and flavonol glycosides (55% of the phenols), catechins (38%), and hydroxybenzoic acids. Concentrations of the main compound, eriodictyol 7-glucoside, varied among cultivars from 3.3 to 6.5 mg/g of stem dry weight. Very high proanthocyanidin contents were found in stems and leaves (10-14% of dry biomass), whereas berries contained a low amount of proanthocyanidins (3% of dry biomass). The findings reveal that leaves and stems of Saskatoon cultivars possess high amounts of various phenolic compounds that may offer new functional raw materials for a wide range of food and health products.     

Evaluation of Saskatoon berry (Amelanchier alnifolia Nutt.) cultivars for their polyphenol content, antioxidant properties, and storage stability

The polyphenol contents and antioxidant activities were assessed for 17 Saskatoon berry cultivars grown in Canada in fresh and stored fruits at -20 degrees C for 9 months. The Nelson cultivar was the richest in total polyphenol, anthocyanin, and procyanidin contents (801, 382, and 278 mg/100 g fresh weight, respectively). This cultivar was characterized also by the highest antioxidant potential measured with DPPH and ABTS radicals (2.8 and 5.0 mM/100 g FW, respectively). Cultivar-dependent changes in polyphenol content after freezer storage were observed. In the Lee 2 cultivar, significant increases in anthocyanin and flavonol contents occurred, while in the Lee 3 and Martin cultivars considerable decreases were observed. During the freezer storage, the antioxidant activity remained unchanged except for the Smokey which showed to be the most sensitive cultivar during storage. The Nelson and Lee 2 were the most stable cultivars during storage. The high polyphenol content and antioxidant activity of the Nelson cultivar and its good storage stability would make this cultivar the optimal material for fruit growers and food producers.     

Structure elucidation of procyanidin oligomers by low-temperature 1H NMR spectroscopy

Procyanidin dimers and trimers, needed as reference compounds for biological studies, have been synthesized from various natural sources using a semisynthetic approach and purified by high-speed countercurrent chromatography (HSCCC). In the past, it has been difficult to elucidate the structure of these compounds, especially the determination of the interflavanoid bond. Here, the structure of two B-type procyanidin dimers, with (+)-catechin ((+)-C) in the upper unit, and eight C-type procyanidin trimers, with (-)-epicatechin ((-)-EC) in the upper unit, have been elucidated using low-temperature (1)H NMR spectroscopy, as well as circular dichroism (CD) spectroscopy. This is the first time NOE interactions have been used to characterize the interflavanoid linkage in underivatized procyanidin trimers. Complete analyses of procyanidin C1 (-)-EC-4β→8-(-)-EC-4β→8-(-)-EC, (-)-EC-4β→8-(-)-EC-4β→8-(+)-C, (-)-EC-4β→6-(-)-EC-4β→8-(-)-EC, (-)-EC-4β→6-(-)-EC-4β→8-(+)-C, (-)-EC-4β→8-(-)-EC-4β→6-(-)-EC, (-)-EC-4β→8-(-)-EC-4β→6-(+)-C, (-)-EC-4β→8-(+)-C-4α→8-(-)-EC, procyanidin C4 (-)-EC-4β→8-(+)-C-4α→8-(+)-C, and procyanidin dimers B6 (+)-C-4α→6-(+)-C and B8 (+)-C-4α→6-(-)-EC are presented.     

Isolation and structure elucidation of antioxidant polyphenols from quince (Cydonia vulgaris) peels

Thirteen new compounds, as well as 16 already known, have been isolated from organic extracts of peels of Cydonia vulgaris, a fruit of a shrub belonging to the same tribe as the apple. All of the structures were elucidated by EI- or ESI-MS and (1)H and (13)C NMR after purification of individual compounds by HPLC. Thirteen fatty acid esters of cinnamyl alcohols, three fatty acid esters of hydroxybenzoic acid, three fatty acid esters of hydroxybenzaldehyde, three glucosides of aromatic acids, four chlorogenic acids, two flavonols, and a benzylamine have been identified. The fatty acid moieties have been identified by GC-MS analysis of the methanolysis products. All of the compounds were tested for their radical scavenging and antioxidant activities by measuring their capacity to scavenge the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical and anion superoxide radical and to induce the reduction of Mo(VI) to Mo(V). The chlorogenic acids and the flavonols exhibited more antioxidant and radical scavenger capacity than the positive standards alpha-tocopherol and ascorbic acid. The results of the tests were analyzed by cluster analysis that grouped all of the compounds on the basis of the substituents on the aromatic ring.     

Characterization of cyanidin- and quercetin-derived flavonoids and other phenolics in mature saskatoon fruits (Amelanchier alnifolia Nutt.)

In order to further characterize the anthocyanins, flavonols, and other phenolics present in mature saskatoon ( Amelanchier alnifolia Nutt.) fruit, extracts were characterized using high-performance liquid chromatography, gas chromatography, and liquid chromatography-mass spectrometry. Cyanidin 3-O-galactoside, cyanidin 3-O-glucoside, cyanidin 3-O-arabinoside, and cyanidin 3-O-xyloside were identified as the four major anthocyanins in the mature fruit. The quercetin-derived flavonols, quercetin 3-O-glucoside, quercetin 3-O-galactoside, quercetin 3-O-arabinoside, quercetin 3-O-xyloside, quercetin 3-O-arabinoglucoside, quercetin 3-O-robinobioside, and quercetin 3-O-rutinoside were also identified in mature fruit extracts. In addition, two chlorogenic acid isomers (hydroxycinnamates), 3-O-caffeoylquinic acid and 5-O-caffeoylquinic acid were detected. The total content of the anthocyanin-, flavonol-, and hydroxycinnamate-type phenolics detected in mature 'Smoky' saskatoon fruit was 140, 25, and 96 mg/100 g fresh weight, respectively. These data further our knowledge of the phenolic composition of mature saskatoon fruit, and as anthocyanins, flavonols, and hydroxycinnamates exhibit antioxidant activities, the presence and levels of these classes of phenolics will aid in the understanding of the potential health-beneficial effects of saskatoon fruits in the human diet.     

Isolation and structural elucidation of some glycosides from the rhizomes of smaller galanga (Alpinia officinarum Hance)

Glycosidically bound compounds were isolated from the methanol extract of fresh rhizomes of smaller galanga (Alpinia officinarum Hance). Nine glycosides (1-9) were finally obtained by reversed-phase HPLC and their structures were elucidated by MS and NMR analyses. They were the three known glycosides, (1R,3S,4S)-trans-3-hydroxy-1,8-cineole beta-D-glucopyranoside (1), benzyl beta-D-glucopyranoside (3), and 1-O-beta-D-glucopyranosyl-4-allylbenzene (chavicol beta-D-glucopyranoside, 4); and the six novel glycosides, 3-methyl-but-2-en-1-yl beta-D-glucopyranoside (2), 1-hydroxy-2-O-beta-D-glucopyranosyl-4-allylbenzene (5), 1-O-beta-D-glucopyranosyl-2-hydroxy-4-allylbenzene (demethyleugenol beta-D-glucopyranoside, 6), 1-O-(6-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranosyl)-2-hydroxy-4-allylbenzene (demethyleugenol beta-rutinoside, 7), 1-O-(6-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranosyl)-4-allylbenzene (chavicol beta-rutinoside, 8), and 1,2-di-O-beta-D-glucopyranosyl-4-allylbenzene (9). Compounds 2-9 were detected for the first time as constituents of galanga rhizomes.     

Isolation and structural elucidation of eight new related analogues of the mycotoxin (-)-botryodiplodin from Penicillium coalescens

Bioassay-guided fractionation of the organic extract derived from the terrestrial fungus Penicillium coalescens led to the isolation of the known mycotoxin (-)-botryodiplodin (1) and eight new structurally related analogues (2-9). The structures of the novel compounds were determined by MS and NMR studies, including 1D and 2D NMR. A likely biogenetic pathway from the aldehydic open form of 1 (C7 unit, U1) is proposed for these metabolites. Among all the isolated metabolites, only (-)-1 showed antifungal, antibacterial, and insecticidal activity. This latter activity appears to be a new property attributed to (-)-1.     

Isolation and structural elucidation of two new glycosides from sage (Salvia officinalis L.)

Six compounds, 1-O-(2,3, 4-trihydroxy-3-methyl)butyl-6-O-feruloyl-beta-D-glucopyranoside, ethyl beta-D-glucopyranosyl tuberonate, p-hydroxybenzoic acid, (-)-hydroxyjasmonic acid, caffeic acid, and 4-hydroxyacetophenone 4-O-[5-O-(3, 5-dimethoxy-4-hydroxybenzoyl)-beta-D-apiofrunosyl]-(1-->2)-beta-D- glu copyranoside, were isolated from the n-butanol-soluble fraction of sage leaf extracts. Their structures were determined by spectral methods (MS, NMR, and 2D-NMR), and their antioxidant activities were measured. Among them, two new glycosides were elucidated. All of these compounds showed DPPH free radical scavenging activity at the concentration of 30 mM, and caffeic acid was the most active compound.     

Carotenoids from guava (Psidium guajava l.): isolation and structure elucidation

Sixteen carotenoids were isolated from the flesh of Brazilian red guavas (Psidium guajava L.). Their structures were established by means of UV-visible, 400 and 500 MHz (1)H NMR, 120 and 125 MHz (13)C NMR, mass, and circular dichroism spectra. The carotenoids were identified as phytofluene, (all-E)-, (9Z)-, (13Z)-, and (15Z)-beta-carotene, (all-E)-gamma-carotene, (all-E)-, (9Z)-, (13Z)-, and (15Z)-lycopene, (all-E,3R)-beta-cryptoxanthin, (all-E, 3R)-rubixanthin, (all-E,3S,5R,8S)-cryptoflavin, (all-E,3R,3'R, 6'R)-lutein, (all-E,3S,5R,6R,3'S,5'R,8'R)-, and (all-E,3S,5R,6R,3'S, 5'R,8'S)-neochrome. Thirteen of the carotenoids identified are reported as guava carotenoids for the first time.     

Cranberry phytochemicals: Isolation, structure elucidation, and their antiproliferative and antioxidant activities

Bioactivity-guided fractionation of cranberries was used to determine the chemical identity of bioactive constituents. Twenty compounds were isolated using gradient solvent fractionation, silica gel and ODS columns, and preparative RP-HPLC. Their chemical structures were identified using HR-MS, 1D and 2D NMR, and X-ray diffraction analysis. Antiproliferative activities of isolated compounds against HepG2 human liver cancer and MCF-7 human breast cancer cells were evaluated. Among the compounds isolated, ursolic acid, quercetin, and 3,5,7,3',4'-pentahydroxyflavonol-3-O-beta-D-glucopyranoside showed potent antiproliferative activities against HepG2 cell growth, with EC50 values of 87.4 +/- 2.7, 40.9 +/- 1.1, and 49.2 +/- 4.9 microM, respectively. Ursolic acid, quercetin, and 3,5,7,3',4'-pentahydroxyflavonol-3-O-beta-D-glucopyranoside showed potent inhibitory activity toward the proliferation of MCF-7 cells, with EC50 values of 11.7 +/- 0.1, 137.5 +/- 2.6, and 23.9 +/- 3.9 microM, respectively. Quercetin, 3,5,7,3',4'-pentahydroxyflavonol-3-O-beta-D-glucopyranoside, 3,5,7,3',4'-pentahydroxyflavonol-3-O-beta-D-galactopyranoside, and 3,5,7,3',4'-pentahydroxyflavonol-3-O-alpha-l-arabinofuranoside showed potent antioxidant activities, with EC50 values of approximately 10 microM. These results showed cranberry phytochemical extracts have potent antioxidant and antiproliferative activities.     

Isolation and identification of oligomers from partial degradation of lime fruit cutin

Complementary degradative treatments with low-temperature hydrofluoric acid and methanolic potassium hydroxide have been used to investigate the protective biopolymer cutin from Citrus aurantifolia (lime) fruits, augmenting prior enzymatic and chemical strategies to yield a more comprehensive view of its molecular architecture. Analysis of the resulting soluble oligomeric fragments with one- and two-dimensional NMR and MS methods identified a new dimer and three trimeric esters of primary alcohols based on 10,16-dihydroxyhexadecanoic acid and 10-oxo-16-hydroxyhexadecanoic acid units. Whereas only 10-oxo-16-hydroxyhexadecanoic acid units were found in the oligomers from hydrofluoric acid treatments, the dimer and trimer products isolated to date using diverse degradative methods included six of the seven possible stoichiometric ratios of monomer units. A novel glucoside-linked hydroxyfatty acid tetramer was also identified provisionally, suggesting that the cutin biopolymer can be bound covalently to the plant cell wall. Although the current findings suggest that the predominant molecular architecture of this protective polymer in lime fruits involves esters of primary and secondary alcohols based on long-chain hydroxyfatty acids, the possibility of additional cross-linking to enhance structural integrity is underscored by these and related findings of nonstandard cutin molecular architectures.     

Isolation of isolectins from Vitis vinifera L. Cv. Chardonnay grape berries

A lectin fraction from Chardonnay grape juice has been isolated by affinity chromatography on a column of p-aminophenyl beta-D-glucoside-derivatized agarose. The lectin fractions agglutinate rabbit and human erythrocytes without serological specificity. None of the usual monosaccharides, glycosides, or glycoproteins inhibit the hemagglutinating activity. Erythroagglutination is only inhibited by nitrophenyl glycosides, p-nitrophenyl beta-D-glucoside being the strongest inhibitor. In SDS-PAGE in the presence of 2-mercaptoethanol and gel filtration HPLC, the lectin fraction gave a single band or peak corresponding to M(r) 13.2-11.9 kDa, thus indicating it to be a monomer. Three bands were observed by isoelectric focusing with pI values of 4.1, 4. 4, and 4.9. The isolectins seem to be glycoproteins since they are bound on a concanavalin A-Sepharose column.     

Isolation and structure elucidation of a new thermal breakdown product of glucobrassicin,the parent indole glucosinolate

The thermal breakdown of glucobrassicin, the major natural indole glucosinolate present in cruciferous vegetables, has been studied. This study has been conducted using pure synthetic glucobrassicin instead of raw vegetable material to eliminate possible other sources (i.e., enzymatic or chemical) of degradation. After 1 h in aqueous solution at 100 degrees C, 10% of the original glucobrassicin is degraded and yields a unique degradation compound. This compound is described for the first time and has been identified as 2-(3'-indolylmethyl)glucobrassicin on the basis of data obtained by (1)H nuclear magnetic resonance spectroscopy as well as tandem mass spectrometric experiments carried out from positive and negative electrospray produced ions.     

Isolation and structural elucidation of some procyanidins from apple by low-temperature nuclear magnetic resonance

Procyanidin fractions from apple were separated according to the degree of polymerization using normal phase chromatography. Evaluation of physiological functionalities of procyanidins requires individual structural determination. However, it is difficult to elucidate the structure of procyanidins, in particular those with (+)-epicatechin (1) or (-)-catechin (2) units, and determine whether the interflavanoid bonds are 4beta-->8 or 4beta-->6 without cleavage and acetylation. Structural determination used LC-MS and low-temperature NMR. Nine procyanidins were separated by preparative HPLC consisting of three well-known procyanidins [procyanidin B1 (3), procyanidin B2 (4), and procyanidin C1 (5)] and six new procyanidins [epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-catechin (6); epicatechin-(4beta-->6)-epicatechin-(4beta-->8)-catechin (7); epicatechin-(4beta-->6)-epicatechin-(4beta-->8)-epicatechin (8); epicatechin-(4beta-->8)-epicatechin-(4beta-->6)-catechin (9); epicatechin-(4beta-->8)-epicatechin-(4beta-->6)-epicatechin (10); and epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-epicatechin (11)]. Compounds 6-11 were detected for the first time as apple constituents.     

Studies on the constituents of a Brazilian folk infusion. Isolation and structure elucidation of new triterpene saponins from Ilex amara leaves.

The isolation of three new triterpene saponins 3beta-O-beta-D-glucopyranosyl-(1-->3)-alpha-L-2-O-acetylarabinopyranosylolean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (2), 3beta-O-beta-D-glucopyranosyl-(1-->2)-alpha-L-O-arabinopyranosylurs-12-en-28-oic acid (3), and 3beta-O-beta-D-glucopyranosyl-(1-->2)-beta-D-O-galactopyranosylurs-12-en-28-oic acid (4) together with five known saponins and one flavonoid glycoside from the aqueous infusion of Ilex amara (Vellozo) Loes. leaves is reported. All structures were elucidated by spectroscopic methods, including the concerted application of one-dimensional (1H, TOCSY, 13C, and 13C DEPT NMR) and two-dimensional NMR techniques (DQF-COSY, HSQC, and HMBC).     

The flavonoid glycosides and procyanidin composition of Deglet Noor dates (Phoenix dactylifera)

The fruits of the date palm (Phoenix dactylifera) are consumed throughout the world and are an important part of the diet in the Middle East. Dates at the rutab and tamar maturity and ripening stages contain a wide array of phenolic antioxidants, but little is known about the composition of phenolic compounds in dates at the khalal stage of ripening. In the current study, the flavonoid glycoside and procyanidin compositions of dates of the cultivar Deglet Noor harvested at the khalal stage of maturity were characterized using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI/MS/MS). Procyanidin oligomers through decamers were identified in extracts of these dates. Higher molecular weight polymers, undecamers through heptadecamers, were also apparent from mass spectra. Thirteen flavonoid glycosides of luteolin, quercetin, and apigenin, 19 when considering isomeric forms, were also identified. Mass spectra indicate that both methylated and sulfated forms of luteolin and quercetin are present as mono-, di-, and triglycosylated conjugates whereas apigenin is present as only the diglycoside. LC-ESI/MS/MS spectra indicate that quercetin and luteolin formed primarily O-glycosidic linkages whereas apigenin is present as the C-glycoside.     

Isolation and structure elucidation of two new flavonoid glycosides from the infusion of maytenus aquifolium leaves. Evaluation of the antiulcer activity of the infusion

Droplet countercurrent chromatography and high-performance liquid chromatography fractionation of the aqueous infusion from Maytenus aquifolium Martius leaves afforded two flavonoid tetrasaccharides: quercetin 3-O-alpha-L-rhamnopyranosyl(1-->6)-O-[beta-D-glucopyranosyl(1-->3)-O- alpha-L-rhamnopyranosyl(1-->2)-O-beta-D-galactopyranoside and kaempferol 3-O-alpha-L-rhamnopyranosyl(1-->6)-O-[beta-D-glucopyranosyl(1-->3)-O- alpha-L-rhamnopyranosyl(1-->2)-O-beta-D-galactopyranoside. All structures were elucidated by spectroscopic methods. Pharmacological essays of the infusion showed antiulcer activity in rats.     

Isolation, structure determination, synthesis, and sensory activity of N-phenylpropenoyl-L-amino acids from cocoa (Theobroma cacao)

Application of chromatographic separation and taste dilution analyses recently revealed besides procyanidins a series of N-phenylpropenoyl amino acids as the key contributors to the astringent taste of nonfermented cocoa beans as well as roasted cocoa nibs. Because these amides have as yet not been reported as key taste compounds, this paper presents the isolation, structure determination, and sensory activity of these amino acid amides. Besides the previously reported (-)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-3-hydroxy-L-tyrosine (clovamide), (-)-N-[4'-hydroxy-(E)-cinnamoyl]-L-tyrosine (deoxyclovamide), and (-)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-tyrosine, seven additional amides, namely, (+)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-aspartic acid, (+)-N-[4'-hydroxy-(E)-cinnamoyl]-L-aspartic acid, (-)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-glutamic acid, (-)-N-[4'-hydroxy-(E)-cinnamoyl]-L-glutamic acid, (-)-N-[4'-hydroxy-(E)-cinnamoyl]-3-hydroxy-L-tyrosine, (+)-N-[4'-hydroxy-3'-methoxy-(E)-cinnamoyl]-L-aspartic acid, and (+)-N-[(E)-cinnamoyl]-L-aspartic acid, were identified for the first time in cocoa products by means of LC-MS/MS, 1D/2D-NMR, UV-vis, CD spectroscopy, and polarimetry, as well as independent enantiopure synthesis. Using the recently developed half-tongue test, human recognition thresholds for the astringent and mouth-drying oral sensation were determined to be between 26 and 220 micromol/L (water) depending on the amino acid moiety. In addition, exposure to light rapidly converted these [E]-configured N-phenylpropenoyl amino acids into the corresponding [Z]-isomers, thus indicating that analysis of these compounds in food and plant materials needs to be performed very carefully in the absence of light to prevent artifact formation.     

Isolation, antifungal activity, and structure elucidation of the glutarimide antibiotic, streptimidone, produced by Micromonospora coerulea.

The antibiotic Ao58A,which showed strong antifungal activity against some plant pathogenic fungi, was purified from the culture broth and mycelial mats of Micromonospora coerulea strain Ao58 using various chromatographic procedures. The molecular formula of the antibiotic Ao58A was deduced to be C(16)H(23)NO(4) (M + H, m/z 294.1707) by high-resolution FAB mass spectroscopy. Analyses of (1)H NMR, (13)C NMR, and 2D NMR spectral data revealed that the antibiotic Ao58A is the glutarimide antibiotic streptimidone, 4-(2-hydroxy-5, 7-dimethyl-4-oxo-6,8-nonadienyl)-2,6-piperidinedione. The antibiotic Ao58A was very effective in inhibiting growth of Phytophthora capsici,Didymella bryoniae, Magnaporthe grisea, and Botrytis cinerea in the range approximately 3-10 microg mL(-)(1) of MICs. In vivo evaluation of the antibiotic Ao58A under greenhouse condition showed strong control efficacies against the development of P. capsici, B. cinerea, and M. grisea on pepper, cucumber, and rice plants, respectively. The antibiotic Ao58A was equally as effective as metalaxyl, vinclozolin, and tricyclazole in the control of these plant diseases. However, it did not show any phytotoxicity on the plants even when treated with 500 microg mL(-)(1).     

煤矿中苏云金芽胞杆菌(Bt)菌株的分离及其鉴定

苏云金芽胞杆菌(Bacillus thuringiensis,Bt)是一种已被广泛用于农业害虫生物防治的昆虫病原细菌。本研究从永春天湖山矿区采集的159份样品中分离出1株Bt,光学显微镜检测发现菱形伴孢晶体。以cry1/7/9、cry2、cry3、cry4/10、cry5、cry6、cry8、cry11和cry1I的通用引物对该Bt分离菌进行Cry毒素基因分析,利用SDS-PAGE和双向电泳-质谱法(2-dimensional electrophoresis/mass spectrometry,2-DE/MS)对Bt分离菌进行蛋白鉴定。结果表明,分离菌含有cry1基因型,经克隆、测序后可知,菌株中的cry1亚基因型与cry1Ac有极高的同源性。分离株表达的晶体蛋白约为130 k D,通过蛋白质谱分析表明,杀虫蛋白为Cry1Ac,与PCR-RFLP所得出的结果一致;通过质谱分析还鉴定出分子伴侣Gro EL、F0F1型ATP-β亚基合成酶、延伸因子Tu和丙酮酸脱氢酶。生物信息学分析结果表明,这些蛋白主要参与帮助新生肽的正确折叠、能源生产和转换,以及提高细胞的应激能力以抵御外界不良刺激。本研究从煤矿中分离鉴定出Bt菌,为发现新资源、新型杀虫蛋白基因以及利用微生物治理重金属污染提供基础资料。