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Potential of peptides and phytochemicals in attenuating different phases of islet amyloid polypeptide fi brillation for type 2 diabetes management

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Food Science and Human Wellness 2021年第3期10卷 259-269页

作者： Raliat O.Abioye chibuike c.udenigwe Department of chemistry and Biomolecular Sciences Faculty of ScienceUniversity of OttawaOttawaOntarioK1N 6N5Canada School of Nutrition Sciences Faculty of Health SciencesUniversity of OttawaOttawaOntarioK1H 8M5Canada

Islet amyloid polypeptide(IAPP),or amylin,has been identifi ed as a key factor in the development of type 2 diabetes(T2D).IAPP aggregates,which form amyloid fi brils,contribute to cytotoxicity of the pancreatic β-cells,resulting in loss of function and subsequent reduction in insulin *** a result,surviving β-cells overcompensate for this reduction of insulin production,further contributing to the loss of function because of increased stress,thus leading to insulin ***,IAPP monomers function in a variety of roles;however,aggregation renders them *** use of naturally occurring compounds,including peptides and phytochemicals,has been explored as a way to mitigate or inhibit IAPP fi bril *** review discusses the structure,endogenous roles and mechanism of IAPP fi bril formation,recent advances on inhibitors of IAPP fi bril formation,and new insights on the future development and application of foodderived inhibitors towards T2D management.

关键词： Islet amyloid polypeptide Fibril formation Disaggregation Bioactive peptides Phytochemicals

Identification of zinc-binding peptides in ADAM17-inhibiting whey protein hydrolysates using IMAc-Zn^(2+) coupled with shotgun peptidomics

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Food Production, Processing and Nutrition 2021年第1期3卷 70-79页

作者： M.chinonye Udechukwu chi Dang chibuike c.udenigwe Department of Plant Foodand Environmental SciencesFaculty of AgricultureDalhousie UniversityTruroNova Scotia B2N 5E3Canada Department of chemistry and Biomolecular Sciences Faculty of ScienceUniversity of OttawaOttawaOntario K1N 6N5Canada School of Nutrition Sciences Faculty of Health SciencesUniversity of OttawaOttawaOntario K1H 8M5Canada

Food components possessing zinc ligands can be used to inhibit zinc-dependent *** this study,zinc-binding peptides were derived from whey protein hydrolysates,and their ultrafiltration(>1 andctions,produced with Esperase(WPH-Esp),Everlase and *** metal affinity chromatography(IMAc-Zn^(2+))increased the zinc-binding capacity of the peptide fraction(83%)when compared to WPH-Esp(23%)and itsction(40%).The increased zinc-binding capacity of the sample increased the inhibitory activity against the zinc-dependent“a disintegrin and metalloproteinase 17”.Lc-MS/MS analysis using a shotgun peptidomics approach resulted in the identification of 24 peptides originating from bovineβ-lactoglobulin,α-lactalbumin,serum albumin,β-casein,κ-casein,osteopontin-k,and folate receptor-αin the *** identified peptides contained different combinations of the strong zinc-binding group of residues,His+cys,Asp+Glu and Phe+Tyr,although cys residues were absent in the *** silico predictions showed that the IMAc-Zn^(2+)peptides were ***,the peptides possessed poor drug-like and pharmacokinetic properties;this was possibly due to their long chain lengths(5–19 residues).Taken together,this work provided an array of food peptide-based zinc ligands for further investigation of structure-function relationships and development of nutraceuticals against inflammatory and other zinc-related diseases.

关键词： Zinc Zinc ligands Food protein Bioactive peptides Immobilized metal affinity chromatography Ultrafiltration ADAM17 Peptidomics Bioinformatics

Occurrence,properties and biological significance of pyroglutamyl peptides derived from different food sources

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Food Science and Human Wellness 2019年第3期8卷 268-274页

作者： Behzad Gazme Ruth T.Boachie Apollinaire Tsopmo chibuike c.udenigwe School of Nutrition Sciences Faculty of Health Sciences415 Smyth RoadUniversity of OttawaOttawaOntarioK1H 8L1Canada Food Science and Nutrition Program Department of ChemistryCarleton University1125 Colonel By DriveOttawaOntario K1S 5B6Canada Department of chemistry and Biomolecular Sciences University of OttawaOttawaOntario K1N 6N5Canada

Pyroglutamyl(pGlu)peptides are formed from intramolecular cyclization of glutamine or glutamic acid residue at the N-terminal position of *** process can occur endogenously or during processing of foods containing the *** factors such as heat,high pressure and enzymatic modifications contribute to pGlu *** peptides are thought to have different characteristics,especially bitter and umani tastes,and thus can affect the sensory properties of foods that contain ***,some health-promoting properties have been reported for pGlu peptides,including hepatoprotective,antidepressant and anti-inflammatory ***,the role of pGlu residue in the peptide bioactivity is not completely established,although the hydrophobic-lactam ring is thought to enhance the peptide stability against degradation by gastrointestinal *** review discusses the occurrence and formation of pGlu peptides in foods,their quantification,sensory and biological properties,and prospects in food applications.

关键词： Pyroglutamyl peptides Peptide quantification Sensory properties Bioactive peptides Bioavailability

Peptidomic analysis of whey protein hydrolysates and prediction of their antioxidant peptides

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Food Science and Human Wellness 2022年第2期11卷 349-355页

作者： Jesus Morales García chibuike c.udenigwe Jorge Duitama Andrés Fernando González Barrios Grupo de Diseño de Productos y Procesos(GDPP) Department of Chemical and Food EngineeringUniversidad de los AndesBogotá111711Colombia School of Nutrition Sciences University of OttawaOttawaOntarioK1N 6N5Canada Systems and computing Engineering Department Universidad de Los AndesBogotá111711Colombia

Enzymatic hydrolysis of proteins is a breakdown process of peptide bond in proteins,releasing some peptides with potential biological *** studies on enzymatic hydrolysis of whey proteins have not identified the complete peptide profiles after *** this study,we reconstructed a profile of peptides from whey hydrolysates with two enzymes and different processing *** also developed an ensemble machine learning predictor to classify peptides obtained from whey hydrolysis.A total of 2572 peptides were identified over three process conditions with two enzymes in duplicate.499 peptides were classified and chosen as potential antioxidant peptides from whey *** peptides classified as antioxidants in the hydrolysates had a proportion of 13.1%-24.5%regarding all peptides *** results facilitate the selection of promising peptides involved in the antioxidant properties during the enzymatic hydrolysis of whey proteins,aiding the discovery of novel antioxidant peptides.

关键词： Whey hydrolysate Antioxidant peptide Peptidomics Prediction

circulation Pattern controls of Summer Temperature Anomalies in Southern Africa

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Advances in Atmospheric Sciences 2024年第2期41卷 341-354页

作者： chibuike chiedozie IBEBUcHI cameron c.LEE Department of Geography Kent State UniversityKentOhio 44242USA climRISE Lab Kent State UniversityKentOhio 44242USA

This study investigates the relationship between circulation patterns and austral summer temperature anomalies in southern Africa. The results show that the formation of continental lows tends to increase the thickness of the lower atmosphere. Further, the distinct variabilities of high and low pressure under the circulation types, influence air mass advection from the adjacent oceans, as well as atmospheric stability over land. Stronger anticyclonic circulation at the western branch of the Mascarene high-pressure system enhances the low-level cold air advection by southeast winds,decreases the thickness, and lowers the temperature over a majority of the land in southern Africa. conversely, a weaker Mascarene High, coupled with enhanced cyclonic activity in the southwest Indian Ocean increases low-level warm air advection and increases temperature anomalies over vast regions in southern Africa. The ridging of a closed South Atlantic anticyclone at the southern coast of southern Africa results in colder temperatures near the tip of southern Africa due to enhanced low-level cold air advection by southeast winds. However, when the ridge is weak and westerly winds dominate the southern coast of southern Africa, these areas experience temperature increases. The northward track of the Southern Hemisphere mid-latitude cyclone, which can be linked to the negative Southern Annular Mode, reduces the temperature in the southwestern part of southern Africa. Also, during the analysis period, El Ni?o was associated with temperature increases over the central parts of southern Africa;while the positive Indian Ocean dipole was linked to a temperature increase over the northeastern, northwestern, and southwestern parts of southern Africa.

关键词： temperature circulation types Subtropical Indian Ocean dipole Southern Annular Mode El Ni?o Indian Ocean dipole Mascarene High South Atlantic anticyclone

Deformation characteristics of granitic rocks in Erguna ductile shear zone,NE china

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Global Geology 2024年第2期27卷 63-75页

作者： NWABUEZE Ekene chibuike LIANG chenyue SONG Zhiwei ZHAO jiaqi ENEZE Florence Ego ZHENG changqing college of Earth Sciences Jilin UniversityChangchun 130061China Key Laboratory of Mineral Resources Evaluation in Northeast Asia Ministry of Natural ResourcesChangchun 130026China School of International Studies Jinan UniversityGuangzhuo 510632China

The Erguna ductile shear zone is situated in the Erguna Massif,which has been exposed along the eastern bank of the Erguna River in northeastern *** authors present comprehensive study results on the macro-and micro-structures,finite strain and kinematic vorticity,quartz electron backscatter diffraction(EBSD)fabrics,and geochronology of granitic rocks in the Erguna ductile shear *** deformed granitic rocks have experienced significant SE-trending dextral strike-slip *** strain and kinematic vorticity in all deformed granitic rocks indicate that the deformation is characterized by simple sheardominated general shearing with S-L *** deformation behaviors and quartz c-axis textures demonstrate that the deformed granitic rocks developed under greenschist to amphibolite facies conditions at deformation temperatures ranging from 450 to 550℃.New LA-IcP-MS zircon U-Pb ages indicate that these granitic rocks were formed in Early Triassic(~248.6 Ma)and Early cretaceous(~136.7 Ma).All the evidence indicates that this deformation may have occurred in Early cretaceous and was related to the compression resulting from the final closure of the Mongol-Okhotsk Ocean.

关键词： zircon U-Pb dating EBSD analysis finite strain kinematic vorticity Erguna ductile shear zone

Qualitative Assessment of Postharvest Stomata and chloroplast Degradation in contrasting Abscission Resistant Balsam Fir (Abies balsamea (L.) Mill.)

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American Journal of Plant Sciences 2023年第9期14卷 1009-1028页

作者： Gaye MacDonald Rajasekaran R. Lada c. D. caldwell chibuike c. udenigwe Mason T. Maconald Faculty of Agriculture Dalhousie University Bible Hill Canada School of Nutritional Sciences Faculty of Health Sciences University of Ottawa Ottawa Canada

Balsam fir is an important christmas tree species, especially in eastern canada. The natural christmas tree industry faces a challenge in postharvest needle abscission. Though there have been many studies describing the physiological triggers and consequences in postharvest balsam fir, there have been no studies describing morphological or ultrastructural changes. Therefore, the objective of this study was to examine changes in stomata and chloroplast of postharvest needles. Branches were collected from low and high needle abscission resistance balsam fir genotypes, placed in water, and displayed in typical household conditions for 11 weeks. Needle abscission, chlorophyll fluorescence, and water uptake were monitored throughout. Needles stomata and chloroplasts were examined under a scanning and transmission electron microscope, respectively, each week. All branches had increased abscission, decreased chlorophyll fluorescence, and decreased water uptake over time. Needle surfaces accumulated fungal hyphae, especially in stomata. chloroplasts demonstrated some dysfunction within two weeks, with notable decreases in chloroplast starch and increases in plastoglobulins. Within several weeks thylakoid membranes had been dismantled as chloroplasts transformed into gerontoplasts. All biophysical and structural changes were more pronounced in low needle abscission resistant genotypes. This research identifies a potential role for needle fungi in postharvest needle abscission and confirms the postharvest senescence of chloroplasts. Though it was previously speculated that chloroplasts must senesce postharvest, this study identifies how quickly this process occurs and that it occurs at different rates in contrasting genotypes.

关键词： Abies balsamea Balsam Fir christmas Tree Fluorescence Needle Abscission Resistance Scanning Electron Transmission Electron

Potential Roles of Fatty Acids and Lipids in Postharvest Needle Abscission Physiology

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American Journal of Plant Sciences 2019年第6期10卷 1069-1089页

作者： Gaye E. MacDonald Rajasekaran R. Lada claude D. caldwell chibuike udenigwe Mason T. MacDonald Department of Plant Food and Environmental Sciences Faculty of Agriculture Dalhousie University Halifax Canada School of Nutrition Sciences Faculty of Health Sciences University of Ottawa Ottawa Canada

Our understanding of postharvest needle abscission physiology in conifers has greatly improved in the last decade. Abscission is initially triggered by root detachment, which begins a cascade of changes such as decreased water uptake, water potential, and auxins and increased membrane injury, ethylene, abscisic acid, volatile terpenes, and catalytic enzymes. Needle abscission is also affected by environmental factors. For example, a period of cold acclimation generally delays postharvest abscission. The aforementioned pieces of evidence, along with previous studies, strongly points to a role for plant lipids and fatty acids. Studies from other species have pointed out key roles in abscission and stress responses for a variety of phospholipids and galactolipids, which has not been studied in balsam fir. It is imperative to have an understanding of the role of plant lipids and fatty acids to further our overall understanding of the physiological mechanisms of postharvest abscission and needle abscission resistance. This review is an overview of membrane lipids and fatty acids, changes that occur postharvest and the interaction that lipids may have in the phenomenon of postharvest abscission.

关键词： Phospholipids Galactolipids Fatty Acids Plant Growth Regulators Abscission

A Mathematical Model for the control of cholera Epidemic without Natural Recovery

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Applied Mathematics 2021年第8期12卷 655-668页

作者： Olaniyi S. Maliki Ogbonna c. chibuike Department of Mathematics Michael Okpara University of Agriculture Abia State Nigeria

In this research work, we present a mathematical model for the control of cholera outbreak without natural recovery. This follows a slight modification as compared to previous cholera models for the Nigerian case. Our model incorporates treatment, water hygiene as well as environmental sanitation. The model employs a system of nonlinear ordinary differential equations, which is analyzed in detail for its stability properties. We compute the basic reproduction ratio R0 for the various control parameters and discover that with proper combination of control measures, the spread of cholera could be minimized. Numerical simulation of the cholera model is done using MathcAD14, and the graphical profiles of the main variables are depicted. We conclude that improvement in treatment, water hygiene and the environmental sanitation is indeed effective in eradicating the cholera epidemic.

关键词： cholera control Model Differential Equations Basic Reproduction Ratio MathcAD Simulation