Papers by Mercedes G. López
Plants
Resilience of growing in arid and semiarid regions and a high capacity of accumulating sugar-rich... more Resilience of growing in arid and semiarid regions and a high capacity of accumulating sugar-rich biomass with low lignin percentages have placed Agave species as an emerging bioenergy crop. Although transcriptome sequencing of fiber-producing agave species has been explored, molecular bases that control wall cell biogenesis and metabolism in agave species are still poorly understood. Here, through RNAseq data mining, we reconstructed the cellulose biosynthesis pathway and the phenylpropanoid route producing lignin monomers in A. tequilana, and evaluated their expression patterns in silico and experimentally. Most of the orthologs retrieved showed differential expression levels when they were analyzed in different tissues with contrasting cellulose and lignin accumulation. Phylogenetic and structural motif analyses of putative CESA and CAD proteins allowed to identify those potentially involved with secondary cell wall formation. RT-qPCR assays revealed enhanced expression levels of...
Aquaculture, 2019
Medicinal plants are alternative supplements to increase antioxidant and immune capacity of farme... more Medicinal plants are alternative supplements to increase antioxidant and immune capacity of farmed fish. In this study, the composition (polyphenols and flavonoids) and antioxidant capacity (FRAP and ABTS) of Chenopodium ambrosioides L. was analyzed; and the effects of dietary (0, 0.5, 1.0, and 2.0%) C. ambrosioides L. on antioxidant and immune parameters were evaluated in Pacific red snapper (Lutjanus peru). The results indicated that C. ambrosioides L. has a strong antioxidant capacity, which was related with a high polyphenol content. Fish fed C. ambrosioides L. had higher hemoglobin content after week 4; while, respiratory burst activity significantly increased in fish fed 0.5% C. ambrosioides L. dose at week 2 and 4. Similarly, leukocyte blood populations significantly increased in fish fed 0.5% C. ambrosioides L. In contrast, fish fed 1.0% C. ambrosioides had antimicrobial activity in skin mucus against Vibrio parahaemolyticus and Aeromonas hydrophila. Moreover, skin mucus anti-protease, lysozyme, and peroxidase activities were enhanced in fish fed 0.5 or 1.0% C. ambrosioides. Finally, superoxide dismutase and catalase activities were higher in fish fed 1.0 or 2.0% C. ambrosioides. In conclusion, the results indicate that dietary C. ambrosioides has antioxidative and immunostimulant properties for innovative applications in finfish. Recently, our research group analyzed the chemical composition of Mexican C. ambrosioides L. and its antioxidant properties, toxicity, and intestinal health in Lutjanus peru (Reyes-Becerril et al., 2019). The major chemical constituents identified in the Chenopodium-extract
Journal of Food Composition and Analysis, 2016
Maple syrup is a natural sweetener obtained from the sap of maple trees (Acer saccharum), highly ... more Maple syrup is a natural sweetener obtained from the sap of maple trees (Acer saccharum), highly rich in bioactive molecules placing it among the most desirable and natural sweeteners for human consumption (agave, sugarcane, corn and honey). Carbohydrate profiles (amounts and composition) as well as FTIR-PCA classification of maple syrup were performed and compared to other natural sweeteners. TLC and HPAEC-PAD revealed that maple syrup exhibits unique carbohydrate profiles dominated by high sucrose content (511-688 mg/g) followed by glucose and fructose traces. Alternately and highly relevant, it was possible to identify three oligosaccharides, not previously reported in maple syrup, with potential to be used as authenticity markers. The FTIR spectra displayed the most characteristic differences in the carbohydrate region (1185-950 cm À1), particularly, maple syrup exhibited strong absorption bands at 997 and 1054 cm À1 wavelengths in agreement with their high sucrose content. Principal component analysis of the FTIR carbohydrates region allowed maple syrup to be distinguished from other natural sweeteners based on botanical source. The above information would be helpful for the authentication, characterization, and subsequent detection of intentional adulteration of this natural sweetener.
Revista Cubana De Ciencia Agricola, 2012
Se presentan generalidades acerca del concepto de prebiótico. Se destacan las características de ... more Se presentan generalidades acerca del concepto de prebiótico. Se destacan las características de los fructanos, dentro de ellos la inulina como aditivo más utilizado a nivel mundial. Se refiere el efecto beneficioso que tiene en la salud y el comportamiento productivo de los animales.
Journal of Plant Biochemistry and Biotechnology, 2015
There is great interest in the fructosyltransferases (FTFs) involved in fructan metabolism and ag... more There is great interest in the fructosyltransferases (FTFs) involved in fructan metabolism and agents affecting their activity. Agaves accumulate fructans, fructose polymers linked by glycosidic β(2-1) and β(2-6) bonds in linear or branched configurations. In plants, fructans provide protection under stress conditions. The sucrose:sucrose 1fructosyltransferase (1-SST), fructan:fructan 1fructosyltransferase (1-FFT), fructan:fructan 6Gfructosyltransferase (6G-FFT), and fructan exohydrolase (FEH) activities were analyzed in micropropagated Agave tequilana plants in the absence and presence of HgCl 2 , AgNO 3 , MgCl 2, sodium deoxycholate (DNa), and sodium dodecyl sulfate (SDS). Kestose, nystose and neokestose were synthesized by the respective FTFs. HgCl 2 and AgNO 3 inhibited all FTFs, mainly up to 90 % in 1-SST and 1-FFT. DNa increased 1-SST (32 %) and 1-FFT (45 %) activities, and SDS increased 6G-FFT activity by 96 %. Finally, AgNO 3 inhibited FEH activity by 78 %. Our results might be relevant on the regulation of FTFs in agave and other crops, for instance by the increment the fructans synthesis in stressed plants.
Plants
Despite the recognition of Agave tequilana Weber var. Azul as raw material for producing tequila ... more Despite the recognition of Agave tequilana Weber var. Azul as raw material for producing tequila and obtaining prebiotics, there are other highly relevant Agave species in Mexico. Oaxaca contains a startlingly diverse range of Agave species; Agave angustifolia Haw. and Agave potatorum Zucc. are two classic specimens with great commercial potential. In this study, we examined the fructan fluctuation in these two species during their lifetime in the field (from 1 to 6 years old). First, we analyzed their morphological diversity based on vegetative characteristics. Subsequently, fructan extracts were analyzed by TLC, FT-IR, and HPAEC-PAD to identify carbohydrates. Multivariate analyses of the morphological parameters indicated a morphological divergence between the two species. Furthermore, we found that the concentration of simple carbohydrates and fructans, as well as the fructan DP, changed during plant development. Glucose, fructose, and fructooligosaccharides (FOS) were more abund...
Foods, 2022
Agavins are prebiotics and functional fiber that modulated the gut microbiota and metabolic statu... more Agavins are prebiotics and functional fiber that modulated the gut microbiota and metabolic status in obese mice. Here, we designed a placebo-controlled, double-blind, exploratory study to assess fluctuations in gastrointestinal (GI) tolerability-related symptoms to increasing doses of agavins in 38 lean and obese Mexican adults for five weeks and their impact on subjective appetite, satiety, metabolic markers, and body composition. All GI symptoms showed higher scores than placebo at almost every dose for both lean and obese groups. Flatulence caused an intense discomfort in the lean-agavins group at 7 g/day, while obese-agavins reported a mild-to-moderate effect for all five symptoms: no significant differences among 7, 10, and 12 g/day for flatulence, bloating, and diarrhea. Ratings for any GI symptom differed between 10 and 12 g/day in neither group. The inter-group comparison demonstrated a steady trend in GI symptoms scores in obese participants not seen for lean volunteers th...
Revista Mexicana de Biodiversidad, 2012
Physicochemical characteristics of Ehretia tinifolia L. fruit are presented for the first time. T... more Physicochemical characteristics of Ehretia tinifolia L. fruit are presented for the first time. The fruit of this plant is a small drupe of 8 mm diameter and weighs 0.2 g. Its pulp is slightly acidic (pH 5.8) with a high ratio of soluble solids (11 °Brix) to acidity (0.1%). The antioxidant activity of E. tinifolia fruits (DPPH, 303.8 mg EVC/100 g f.w.; ABTS, 84.1 mg EVC/100 g f.w.; DPPH, ABTS and EVC mean 1,1-diphenyl-2-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazolin-6-sulfonate) diammonium salt, and equivalents of vitamin C, respectively) was similar or higher than reported for several tropical fruits (e.g. orange, guava, and prickly pear). Ehretia tinifolia fruit has a high content of ash (12.6 mg/100 g d.w.). The edible portion is an important source of selenium (0.1 mg/100 g d.w.) and total fatty acids were 834.8 mg/100g d.w.; the main fatty acids were palmitic (27.6%), linoleic (26.4%), linolenic (18.1%), and oleic (17.6%). The content of fatty acids of seeds was 5 137...
Scientific Reports, 2021
In the pharmaceutical industry nano-hydrocolloid systems frequently coalesce or present nanoparti... more In the pharmaceutical industry nano-hydrocolloid systems frequently coalesce or present nanoparticle aggregation after a long storage periods. Besides, the lyophilization process used to dry nanoparticles (NPs) produces loss of their original properties after dispersion. In this work we evaluated the effect on morphology and physicochemical properties of different protective excipients during drying of bovine serum albumin (BSA) NPs loaded with different concentrations of capsaicin. Capsaicin concentrations of 0, 812, 1625, 2437, and 3250 µg mL−1 were used; subsequently, NPs were dried with deionized water (DW), NaCl (DN), sucrose (DS), and not dried (ND). We found that ND, DW, and DN treatments showed a negative effect on the NPs properties; while, DS reduced the aggregation and produced the formation of isolated nanoparticles at higher concentrations of capsaicin (3250 µg mL−1), improving their circular shape, morphometrical parameters, and ζ-potential. The stability of the BSA-ca...
Molecules, 2019
Capsaicin is a chemical compound found in pungent chili peppers (Capsicum spp.). In biotechnology... more Capsaicin is a chemical compound found in pungent chili peppers (Capsicum spp.). In biotechnology, capsaicin has been proposed as a pathogen control; however, its low solubility in water and high instability limits its uses. The aim of this work was to study the effect of high concentrations of capsaicin on the synthesis of nanoparticles and to evaluate their inhibitory effect on the growth of Rhodotorula mucilaginosa yeast. Bovine serum albumin (BSA)-capsaicin nanoparticles were formulated at 0, 16.2, 32.5, 48.7 and 65.0 µg of capsaicin per mg of BSA. Nanoparticle properties were evaluated and they were added to cultures of R. mucilaginosa to quantify their effect on cell viability. We found that increased capsaicin levels caused several changes to the physicochemical parameters, probably due to changes in the hydrophobicity sites of the albumin during the nanostructuration. The administration of nanoparticles to cultures of R. mucilaginosa produced a maximal viability with nanopar...
Food Science and Biotechnology, 2017
ACS Symposium Series, 2006
Agave tequilana Weber azul variety, a CAM (crassulacean acid metabolism) plant, is the only raw m... more Agave tequilana Weber azul variety, a CAM (crassulacean acid metabolism) plant, is the only raw material used to make Tequila, the most well known distilled spirit in Mexico with origin denomination followed in importance by Mezcal, Sotol, Bacanora, and Sisal. All of these spirits are obtained from the fermentation of agavins from different Agave species. In the last decade, Tequila consumption has increased tremendously worldwide and its authenticity is of a high concern to Mexican government and consumers. Authenticity studies of Mexican distilled spirits have been a priority in our group for many years. The case of Tequila is presented in this work. To establish the authenticity of Tequila, different analytical studies have been performed including SPME-GC-MS profiles, NIR-SIMCA determinations, GC-O, and GC-IRMS. Blanco, Reposado, and Anejo Tequilas types of both categories (100% and mixed) were used in all determinations. SPME-GC-MS results demonstrated the presence of volatile compounds that permitted to establish some qualitative and quantitative differences among all Tequila types. Tequila types were clearly and easily grouped by NIR-SIMCA measurements but better recognition and validation were found for the Reposado type. By GC-O analyses, the most potent volatiles of authentic Tequilas based on Charm values (numbers in the parentheses) were, an unknown (16956), phenylethyl alcohol (7771), butanol-3-methyl (6515), vainillin (5510), and a terpenoid (4733). Finally, authenticity of all types and categories of Tequilas was possible using stable isotope determinations. The measured δ 13/12 C (-12.05 to -14.82o/oo) values were within the CAM range isotopic values which undoubtfully allowed to establish the plant origin, Agave tequilana Weber azul variety.
Journal of Agricultural and Food Chemistry, 2006
A large collection (n = 95) of Mexican Agave spirits with protected appellations of origin (Tequi... more A large collection (n = 95) of Mexican Agave spirits with protected appellations of origin (Tequila, Mezcal, Sotol, and Bacanora) was analyzed using ion and gas chromatography. Because of their production from oxalate-containing plant material, all Agave spirits contained significant concentrations of oxalate (0.1-9.7 mg/L). The two Tequila categories ("100% Agave" and "mixed") showed differences in the methanol, 2-/3-methyl-1-butanol, and 2-phenylethanol concentrations with lower concentrations in the mixed category. Mezcal showed no significant differences in any of the evaluated parameters that would allow a classification. Sotol showed higher nitrate concentrations and lower 2-/3-methyl-1-butanol concentrations. Bacanora was characterized by exceptionally high acetaldehyde concentrations and a relatively low ethyl lactate content. The methanol content was the most problematic compound regarding the Mexican standards: two Tequilas (4%), five Sotols (31%), and six Bacanoras (46%) had levels above the maximum methanol content of 300 g/hL of alcohol. In conclusion, the composition of Mexican Agave spirits was found to vary over a relatively large range.
Metabolomics - New Insights into Biology and Medicine, 2020
Targeted and non-targeted metabolite profiling can identify biomarkers after a dietary treatment ... more Targeted and non-targeted metabolite profiling can identify biomarkers after a dietary treatment leading to a better understanding of interactions between diet and health. This study was conducted to establish enriched or depleted metabolites in the feces of overweight mice after a diet shift plus agavins or inulins supplementation, and their possible association with beneficial effects on host health. Thirty-eight male C57BL/6 mice were fed with a high-fat diet for 5 weeks followed by a diet shift to a standard diet supplemented with agavins (HF-ST + A) or inulins (HF-ST + I) for five more weeks. Feces were collected before and after prebiotic supplementation for metabolomics analyses. HF-ST + I group increased the fecal excretion of two methyl esters: linoleic and oleic acid, while HF-ST + A mice showed a substantial augment of 2-decenal, fructose, cyclohexanol, and the acids: 10-undecenoic, 3-phenyllactic, nicotinic, 5-hydroxyvaleric, and lactic. From the metabolites identified in HF-ST + A, only lactic acid has been reported previously and associated with beneficial effects on host health. However, the identification of new metabolites, coming from the microbial fermentation of agavins, opens opportunities to transform this information into practical solutions to tackle overweight and associated metabolic syndrome.
Prebiotics of the inulin-type fructans have been studied for many years under a wide range of con... more Prebiotics of the inulin-type fructans have been studied for many years under a wide range of conditions, including concentration, degree of polymerization and variety of probiotics. This work is the first that addresses the potential of Agave spp. and Dasylirion sp. fructans as prebiotics. Fructans from five different Agave species and from Dasylirion sp. grown in six different geographic areas were tested with six different bifidobacteria and four lactobacilli strains, with commercial inulin-type fructans used as positive controls. Results indicate that bifidobacteria and lactobacilli grew using species of Agave and Dasylirion fructans as a carbon source. Most fructans stimulated the growth of both genera more efficiently than commercial inulin, as indicated by the absorbance and pH values. Fructans of Dasylirion sp. from Chihuahua and Agave tequilana from Guanajuato were the most effective, followed by RaftiloseSynergy1, a commercial inulin. This study supports previous reports t...
Tropical Animal Health and Production
This study investigated Lippia palmeri Watt (oregano) phytochemical compounds, their antioxidant ... more This study investigated Lippia palmeri Watt (oregano) phytochemical compounds, their antioxidant capacity, and immunological effects on goat peripheral blood leukocytes (PBL), and on the presence of intermediate polar compounds in goat feces fed dietary oregano. The polar and nonpolar fractions of L. palmeri W. were characterized and phytochemical contents and antioxidant capacity were determined. Twelve healthy Anglo-Nubian goats were used for the in vivo trials, which were randomly assigned to control fed with basal diet, or oregano group fed with basal diet + 2.6% (DM basis) dried oregano leaves. Goat peripheral blood leukocytes (PBL) were isolated for the in vitro study, and PBL were stimulated with oregano extracts at 100 and 150 μg/mL after 24 h. For the in vivo trial, dietary oregano (2.6% on DM basis) was evaluated in the goats for 90 days. Relatively high abundance of carvacrol and thymol phytochemical compounds was found in oregano. The highest antioxidant capacity of oregano extracts was detected at 100 and 150 μg/mL. Nitric oxide production, phagocytosis, and superoxide dismutase activities increased ( p < 0.05) in stimulated PBL with oregano extracts, whereas the pro-inflammatory (TNF-α and IL-1β) transcription and antioxidant (CAT and GPX-4) genes downregulated. In the in vivo experiment, dietary oregano enabled the detection of nine compounds found in goat feces, from which caproic (C6) was in a high relative quantity compared with the control group. Oregano has phytochemical compounds with strong antioxidant capacity that protect cells against oxidative stress damage and could modulate immune response and feces composition in goats.
Biomolecules
Botryococcus braunii produce liquid hydrocarbons able to be processed into combustion engine fuel... more Botryococcus braunii produce liquid hydrocarbons able to be processed into combustion engine fuels. Depending on the growing conditions, the cell doubling time can be up to 6 days or more, which is a slow growth rate in comparison with other microalgae. Few studies have analyzed the cell cycle of B. braunii. We did a bioinformatic comparison between the protein sequences for retinoblastoma and cyclin-dependent kinases from the A (Yamanaka) and B (Showa) races, with those sequences from other algae and Arabidopsis thaliana. Differences in the number of cyclin-dependent kinases and potential retinoblastoma phosphorylation sites between the A and B races were found. Some cyclin-dependent kinases from both races seemed to be phylogenetically more similar to A. thaliana than to other microalgae. Microscopic observations were done using several staining procedures. Race A colonies, but not race B, showed some multinucleated cells without chlorophyll. An active mitochondrial net was detect...
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Papers by Mercedes G. López