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Systems microbiology and Biomanufacturing 2022年第3期2卷 523-532页

作者： m.Venkateswar Reddy Alexander Steinbüchel Institut für molekulare mikrobiologie und Biotechnologie Westfälische Wilhelms-Universität Münster48149 MünsterGermany Center for Biotechnology and Interdisciplinary Studies Rensselaer Polytechnic Institute1108th StreetTroyNY 12180USA Environmental Sciences Department King Abdulaziz UniversityJeddahSaudi Arabia

The bacterium Rhodococcus erythropolis mI2 uses 4,4´-dithiodibutyric acid(DTDB)as carbon source to synthesize polythioesters(PTE).The first step for the production of PTE using DTDB is catalyzed by an NADH:flavin oxidoreductase(nox)as it was previously shown in our laboratory,and the second step is catabolized by a putative luciferase-like monooxygenase(Llm).In the current study,experiments were carried out to identify the function of ***,the llm gene,which encodes for the Llm protein,was amplified from the genomic DNA of mI2 using polymerase chain reaction and expressed in Escherichia coli BL21 *** purification was done using His Spin Trap affinity *** assay was carried out using the purified protein and p-coumaric acid as substrate giving a specific activity of 1.6 U/mg protein for the purified *** responsible gene(llm)was deleted in the genome of mI2,and a single deletion mutant was subsequently ***,growth of the wild-type strain(mI2)and the mutant strain(mI2Δllm)were compared using DTDB or succinate as carbon *** the wild type was successfully grown with DTDB or succinate,the llm-negative mutant exhibited low grow with DTDB although it grows very well with succinate.

关键词： Deletion mutant monooxygenase Polythioesters Protein purification Rhodococcus erythropolis mI2 4,4´-Dithiodibutyric acid(DTDB)

Growth of silicon nanowires in aqueous solution under atmospheric pressure

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Nano Research 2014年第6期7卷 898-902页

作者： Nae-man Park chel-Jong Choi Components and materials Laboratory Electronics and Telecommunications Research Institute (ETRI) 161 Gajeong-dong Yuseong-gu Daejeon 305-700 Republic of Korea School of Semiconductor and Chemical Engineering Semiconductor Physics Research Center Chonbuk National University 664-14 Deokjin-dong Deokjin-gu Jeonju 561-756 Republic of Korea

A new method for growing silicon nanowires is presented. They were grown in an aqueous solution at a temperature of 85℃ under atmospheric pressure by using sodium methylsiliconate as a water-soluble silicon precursor. The structure, morphology, and composition of the as-grown nanowires were characterized by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectrometry. It was also confirmed by X-ray powder diffraction and Raman spectroscopy that the silicon nanowire has a hexagonal structure. It was possible to grow the crystalline silicon nanowires at low temperature under atmospheric pressure because potassium iodide, which was used as a gold etchant, sufficiently increased the surface energy and reactivity of gold as a metal catalyst for the reaction of the Si precursor even at low temperature.

关键词： Silicon nanowire solution process metal catalyst hexagonal crystalline phase

ACE-I inhibitory peptide fractions from enzymatic hydrolysates of velvet bean (mucuna pruriens)

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Agricultural Sciences 2013年第12期4卷 767-773页

作者： maira Rubi Segura-Campos Carlos Paul Espadas-Alcocer Luis chel-Guerrero David Betancur-Ancona Facultad de Ingeniería Química Universidad Autónoma de Yucatán Mérida México

The hydrolysis of velvet bean (mucuna pruriens) protein in the presence of Alcalase?-Flavourzyme? and Pepsin-Pancreatin was investigated. The results showed that Alcalase?-Flavourzyme? (29.08%) sequential system catalyzed the hydrolysis most efficiently that Pepsin-Pancreatin (24.78%). In addition, the higher ACE-I inhibitory activity was achieved with the sequential system Alcalase?-Flavourzyme? (33.13%). Furthermore, the concentration of peptides employing an ultrafiltration (UF) system or their purification by gel filtration chromatography showed that the oligomeric peptides with lower molecular weight registered the highest ACE-I inhibitory activity. It has been demonstrated that mucuna pruriens protein hydrolysates could serve as a source of peptides with ACE inhibitory activity and this activity can be attributed mainly to the mixture of short peptides in the hydrolysate.

关键词： Velvet Bean mucuna pruriens ACE-I Inhibition Peptide Fractions Enzymatic Hydrolysis

Chemical and Functional Properties of Hard-to-Cook Bean (Phaseolus vulgaris) Protein Concentrate

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Food and Nutrition Sciences 2014年第21期5卷 2081-2088页

作者： maira R. Segura-Campos Jimena Cruz-Salas Luis chel-Guerrero David Betancur-Ancona Facultad de Ingenierí a Quí mica Universidad Aut&#243 noma de Yucatá n M&#233 rida M&#233 xico

The objective of this research was to evaluate the chemical and functional properties of hard-to-cook (HTC) bean (Phaseolus vulgaris) protein concentrate to determine their potential practical applications. The respective protein concentrate was obtained from the flour using isoelectric precipitation and the protein content was 73.03%. Proximate composition and in vitro digestibility were measured to evaluate the chemical properties, and nitrogen solubility, emulsifying capacity, emulsion stability, foaming capacity, foam stability and viscosity were measured to evaluate its functional properties. The proximate composition of the HTC bean (P. vulgaris) flour and protein concentrate registered values of moisture, ash, protein, fat, fiber and NFE of 8.92, 4.52, 21.71%, 4.41%, 4.11% and 65.25% for flour and of 2.68%, 2.54%, 73.03%, 2.77%, 1.31% and 20.35% for protein concentrate. The in vitro digestibility was of 76.7%. The hard-to-cook bean protein concentrate exhibited good functional properties suggesting its use as additive. This concentrate registered solubility values that are ranging from 2.5% to 71.81%. The emulsifying (EC) and foaming capacity (FC) registered values of 89% - 97% and of 7% - 53% at different pH levels, respectively as well as an emulsion (ES) and foaming stability (FS) pH- and time-dependent. The HTC bean (P. vulgaris) protein concentrate registered a viscosity profile dependent of shear rate. The results suggest that HTC bean (P. vulgaris) protein concentrate is a valuable food ingredient or additive.

关键词： Hard-to-Cook Bean Phaseolus vulgaris Protein Concentrate Chemical and Functional Properties

Protein Fortification of Corn Tortillas: Effects on Physicochemical Characteristics, Nutritional Value and Acceptance

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Food and Nutrition Sciences 2012年第12期3卷 1658-1663页

作者： Abril Lecuona-Villanueva David A. Betancur-Ancona Luis A. chel-Guerrero Arturo F. Castellanos-Ruelas Faculty of Chemical Engineering Autonomous University of Yucatán Campus of the Faculties of Engineering and Math Sciences Mérida México.

The aim of this study was to evaluate the texture of corn dough as well as the nutritional quality and acceptance of corn cakes (tortillas) made either with a readymade commercial corn flour (CCF) or with a traditional way (nixtamal) both fortified with lys + tryp (L + T) or with a protein concentrate from Phaseolus lunatus added with L + T (PC + L + T). All treatments were analyzed to investigate the physical properties of the dough and tortillas as well as their physicochemical and nutritional quality. Results showed that cohesion was affected (p tortillas made with nixtamal showed no difference. Adhesion was not affected by treatments. Weight loss increased only in the fortified tortillas made with CCF (p tortillas increased with the fortification being the highest value 0.96 N. Color was not affected in tortillas made with CCF (p tortillas made with CCF and fortified with PC + L + T. Acceptance was greater for tortillas fortified with L+T alone. Protein fortification of tortillas made with either CCF or nixtamal is feasible using either L + T together or in combination with a PC from Phaseolus lunatus improving their nutritional value without negative effects on their physicochemical characteristics or acceptance.

关键词： Tortilla Amino Acids Child malnutrition Fortification

Physicochemical characterization of chia (Salvia hispanica) seed oil from Yucatán, méxico

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Agricultural Sciences 2014年第3期5卷 220-226页

作者： maira Rubi Segura-Campos Norma Ciau-Solís Gabriel Rosado-Rubio Luis chel-Guerrero David Betancur-Ancona Facultad de Ingeniería Química Universidad Autónoma de Yucatán Mérida México

A physicochemical characterization of oil from chia seeds was carried out. Proximate composition analysis showed that fat and fiber were the principal components in the raw chia flour. Physical characterization showed that chia oil has a relative density from 0.9241, a refraction index of 1.4761 and a color with more yellow than red units. Chemical characterization showed that chia oil registered an acidity index of 2.053 mg KOH/g oil, a saponification index of 222.66 mg KOH/g oil, a content of unsaponifiable matter of 0.087%, an Iodine index of 193.45 g I/100 g oil and a peroxide index of 17.5 meq O2/kg oil. Chia oil showed a higher content of α and β linolenic and palmitic acids. Chia oil is the vegetable source with the highest content of essential fatty acids.

关键词： Chía Salvia hispanica Oil Physicochemical Characteristic

Lima Bean(Phaseolus lunatus)Protein Hydrolysates with ACE-I Inhibitory Activity

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Food and Nutrition Sciences 2012年第4期3卷 511-521页

作者： Luis chel-Guerrero mario Domínguez-magana Alma martínez-Ayala Gloria Dávila-Ortiz David Betancur-Ancona Facultad de Ingeniería Química Universidad Autónoma de YucatánMéridaMéxico Escuela Nacional de Ciencias Biológicas Instituto Politécnico NacionalMiguel HidalgoMéxico Centro de Investigación en Biotecnología Aplicada Instituto Politécnico NacionalTlaxcalaMéxico

Several protein sources can be used to produce bioactive peptides with angiotensin I-converting enzyme (ACE) inhibittory activity. Protein concentrates from ungerminated and germinated lima bean Phaseolus lunatus seed flours were hydrolyzed with Alcalase 2.4 L or pepsin-pancreatin sequential hydrolysis, and ACE inhibitory activity measured in the different hydrolysis treatments. Protein hydrolysate production was analyzed with a 23 factorial design with four replicates of the central treatment. Evaluated factors were protein concentrate source (ungerminated seeds, PC1;germinated seeds, PC2), enzyme/substrate ratio E/S (1/50 or 1/10) and hydrolysis time (0.5 or 2.0 h for Alcalase;1 or 3 h for pepsin-pancreatin). Degree of hydrolysis (DH) was high for the Alcalase hydrolysates (24.12% 58.94%), but the pepsin-pancreatin hydrolysates exhibited the highest ACE inhibitory activity (IC50 = 0.250 0.692 mg/mL). Under the tested conditions, the hydrolysates with the highest ACE inhibitory activity were produced with sequential pepsin-pancreatin using either PC1 at 1 h hydrolysis time and a 1/10 E/S ratio or PC2 at 1 h hydrolysis time and a 1/50 E/S ratio. Lima bean protein hydrolysates prepared with Alcalase or pepsin-pancreatin are a potential ingredient in the production of physiologically functional foods with antihypertensive activity.

关键词： Lima Bean Degree of Hydrolysis ACE Inhibition Protein Hydrolysates IC50

Physicochemical and Functional Characterization of mucuna pruriesDepigmented Starch for Potential Industrial Applications

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International Journal of Organic Chemistry 2015年第1期5卷 1-10页

作者： maira Rubi Segura-Campos Sonia marina López-Sánchez Arturo Castellanos-Ruelas David Betancur-Ancona Luis chel-Guerrero Facultad de Ingeniería Química Universidad Autónoma de Yucatán Mérida México

Starch is a very important biopolymer in the food industry. The velvet bean (m. pruriens) is an excellent potential starch source containing approximately 520 g starch per kg. The objective of this study was to evaluate the physicochemical and functional properties of velvet bean depigmented starch. The starch granules appear oval and spherical shaped. The colour registered L*, a*, b* values of 44.9, 0.324 and 0.341 respectively. The chemical composition registered values of moisture, ash, fat, protein, fibre and NFE of 110.5, 5.8, 5.7, 0.0, 34 and 954.5 g/kg respectively, as well as amylose levels of 215.3 g/kg. Gelatinization onset (To), peak (Tp) and final (Tf) temperatures were of 74.23°C, 80.57°C and 86.39°C. The solubility (3.1% - 16.2%), swelling power (SP) (2.86% - 16.17%) and water absorption capacity (WAC) (2.67 - 15.95 g water/g starch) were directly correlated to temperature (60°C - 90°C). The enthalpy values (4.10 - 13.47 j/g) were directly correlated to the time (1 - 21 days). The retrogradation increased as time increased. The viscosity of m. pruriens depigmented starch decreased slightly during the heating stages and then increased during cooling and the refrigeration and freezing stability registered syneresis ranges from 17.65 to 23.18 mL/50mL and from 16.4 to 22.6 mL/50mL respectively, indicating that the depigmented starch was unstable in heating-cooling processes.

关键词： Depigmented Starch Functional Properties mucuna pruriens Physicochemical Properties

Physicochemical and Functional Properties of Dehydrated Japanese Quail (Coturnix japonica) Egg White

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Food and Nutrition Sciences 2013年第3期4卷 289-298页

作者： maira Segura-Campos Roberto Pérez-Hernández Luis chel-Guerrero Arturo Castellanos-Ruelas Santiago Gallegos-Tintoré David Betancur-Ancona Faculty of Chemical Engineering Campus of Exact Sciences and Engineering Autonomous University of Yucatán Merida Mexico Faculty of Chemical Engineering Campus of Exact Sciences and Engineering Autonomous University of Yucatán Merida Mexico Inalim Food Industry Oaxaca Mexico.

Physicochemical, functional and digestibility analyses were done of dehydrated quail egg white to determine its possible practical applications. Quail egg white was dehydrated by air convection using one of two temperatures and times: m1 (65℃, 3.5 h), m2 (65℃, 5.0 h), m3 (70℃, 3.5 h) and m4 (70℃, 5.0 h). Lyophilized quail egg white was used as a standard. All four air-dried treatments had good protein levels (92.56% to 93.96%), with electrophoresis showing the predominant proteins to be lysozyme, ovalbumin and ovotransferin. Denaturation temperatures ranged from 81.16℃ to 83.85℃ and denaturation enthalpy values from 5.51 to 9.08 J/g. Treatments m1-4 had lower water-holding (0.90 - 2.95 g/g) and oil-holding (0.92 - 1.01 g/g) capacities than the lyophilized treatment (4.5 g/g, 1.95 g/g, respectively). Foaming capacity was pH-dependent in all five treatments, with the lowest values at alkaline pH and the highest (153% to 222%) at acid pH (pH 2). Foam stability was lowest at acid pH and highest at alkaline pH. Emulsifying activity in the air-dried treatments was highest at pH 8 (41% - 46%). Emulsion stability was pH-dependent and highest in m3 between pH 2 and 4 (96.16% to 95.74%, respectively). In the air-dried treatments, in vitro protein digestibility was as high as 83.02% (m3).

关键词： Coturnix japonica Dehydrated Egg White Physicochemical Properties Functional Properties

膀胱内滴注5-氨基乙酰丙酸行尿路上皮肿瘤的光动力学诊断

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德国医学 1995年第1期12卷 34-35页

作者： m.Kriegmair R.Baumgartner R.Knüchel A.Ehsan P.Steinbach W.Lumper F.Hofstdter A.Hofstetter 李金华 Klinik für Urologie der Universitat münchen Marchioninistr15.D-81377 MünchenGermany Institut für Pathologie der Universitat Regensburg. 湖北省荆州人民医院

表浅膀胱癌病人的预后除了被切除的肿瘤因素外,主要取决于存留粘膜的癌前期和恶性变化。本文报告一种诊断难予辨认的和表浅原位尿路上皮损害的新方法,这种方法的基础是膀胱内使用5-氨基乙酸丙酸(ALA)后,内原性产生荧光的原卟啉Ⅸ选择性... 详细信息

表浅膀胱癌病人的预后除了被切除的肿瘤因素外,主要取决于存留粘膜的癌前期和恶性变化。本文报告一种诊断难予辨认的和表浅原位尿路上皮损害的新方法,这种方法的基础是膀胱内使用5-氨基乙酸丙酸(ALA)后,内原性产生荧光的原卟啉Ⅸ选择性积聚于肿瘤,使用紫光激发产生荧光,微细乳头状瘤、结构不良的损害和原位癌呈浅红色。

关键词：氨基乙酰丙酸尿路上皮肿瘤肿瘤光动力学诊断