College of Agriculture & Natural Resources
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Three Clostridium species with Health Imparting Properties: In vitro Screening for Probiotic Potential(2024) Mochama, Victor Moronge; Obanda, Diana; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This research aimed to unlock the probiotic potential of the genus Clostridium, which is often overshadowed by the predominant focus on pathogenic species. The study specifically targeted three promising Clostridium species: C. disporicum, C. celatum, and C. vincentii, which have shown potential in mitigating diet-induced obesity. Despite the challenges presented by the anaerobic growth requirements of Clostridium bacteria, the study capitalized on their capacity to sporulate. This characteristic provides an avenue to use them as probiotics, with resilient and dormant spores capable of surviving food processing and harsh stomach conditions. The resilience of these spores was examined by exposing them to oxygen, heat, gastrointestinal juices, and bile salts. The spores survived oxygen exposure, exhibited resilience to both bile salts and gastric acids, and demonstrated a survival temperature of 70°C. When exposed to suitable germination conditions in vitro, the spores successfully germinated. The study assessed the colonization potential of the bacteria by evaluating their adhesion ability, and all bacteria were found to have the adhesion ability. Furthermore, a safety assessment was conducted by examining hemolytic activity and antibiotic susceptibility to selected antibiotics. The bacteria were found to be susceptible to the antibiotics and did not exhibit hemolytic activity. Bile salt hydrolase (BSH) activity and antibacterial activities were also assessed, and none of the bacteria exhibited BSH activity or antibacterial activity. Antioxidant tests revealed that C. vincentii had the highest antioxidant properties. Assessment of anti-inflammatory properties showed that C. celatum downregulated the gene expression of cytokine inflammation markers IL-6, IL-1, and iNOS while upregulating TGF-β expression. In summary all 3 bacterial species showed good probiotic potential from the in vitro tests. Particularly the formation of resistant spores that later germinated to vegetative cells that produced molecular patterns with antioxidant and anti-inflammatory properties. This necessitates further studies on their probiotic properties.Item Antiproliferative Activity of Soybean and Tempeh Extracts on Human Colorectal Cancer Cells(2024) Fan, Rongjie; Lee, Seong-Ho; Wei, Cheng-I; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Tempeh, an indigenous Indonesian soybean product, is produced through a fermentation process of soybean that enhances the bioavailability of its beneficial nutrients such as proteins and phytoestrogens. Recent studies suggest that the fermentation process of tempeh may enhance the biofunctionality properties of soybeans including anticancer activity. The current study is designed to present a comparative analysis to see if defatted extracts of unfermented soybeans and tempeh (fermented soybeans) possess anti-proliferative activity in human colorectal cancer (CRC) cells. The experimental methods involve the production and extraction of soybeans extract (SE) and tempeh extract (TE) at a concentration of 35 g/100 mL (w/v) with 70% ethanol, followed by rotary evaporation and freeze-drying. MTT assays indicated that both SE and TE exhibited inhibitory activity in viability of human CRC cells, with TE demonstrating a more pronounced dose-dependent inhibition of cell growth compared to SE. Cell cycle analysis led to a significant increase of G1 arrest in both SE and TE-treated cells. The induction of apoptosis was observed from the cells treated with both SE and TE. Western blot analysis revealed an increase of PARP cleavage for both treatments, demonstrating activation of apoptotic pathways in SE and TE-treated cells.Item FUNCTIONAL FOODS THAT MANIPULATE THE GUT MICROBIOTA COMPOSITION AND REGULATE THE INTESTINAL IMMUNE SYSTEM-Urtica dioica a CASE STUDY(2024) Fan, Si; Obanda, Diana; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The prevalence of obesity and its comorbidities, such as insulin resistance and type 2 diabetes are major concerns. Diet-induced obesity and insulin resistance are associated with gut microbiota dysbiosis, specifically, a reduction in diversity and an increase in bacteria taxa linked with host tissue inflammation and extra energy harvest. Prevention strategies focusing on modification of diet and physical activity levels are beneficial, effective, and cost-efficient but difficult to maintain in the long term.Urtica dioica is widely used as a food in several cultures and its extract has been widely studied for intervention against several diseases, but the molecular mechanisms involved are unclear. In addition, most studies have focused on the extract but not the plant as a whole food. Because U. dioica exerts pleiotropic effects in several tissues, we hypothesized that its phytochemicals get into the systemic circulation to reach target tissues, such as abdominal adipose tissue and skeletal muscle but also impact obesity and insulin resistance through pathways involving the gut microbiota and ultimately the gut immune system. The data presented herein was acquired in a mouse model of obesity and insulin resistance. Supplementing the food with whole U. dioica vegetable, attenuated high fat (HF) diet-induced weight gain, fat accumulation, insulin resistance and changed the gut microbiota composition, by increasing diversity and promoting the proliferation of species from the genus Clostridium. This taxon has associated with lower body weight and activation of regulatory T cells (Tregs) in the intestinal immune system. In a second study, we confirmed that U. dioica induced T cells antigenic stimulation, promoted the activation of Tregs and overall protected against HF diet inflammation. Furthermore, besides attenuating HF diet induced fat accumulation, U. dioica promoted the browning or beiging of adipose tissue as evidenced by enhanced gene expression of key markers of this process. Brown or beige adipose tissue displays enhanced fat oxidation. Finally using enteroids derived from small intestinal tissue, we show that in presence of excess nutrients, supplementation with U. dioica reduces the amount fatty acids and glucose absorbed. In conclusion, supplementing a HF diet with U. dioica attenuates fat accumulation and insulin resistance via mechanisms involving the gut microbiota composition and function, the gut immune system and associated inflammation and moderation of amounts of macronutrients absorbed.Item FERMENTING KALE VEGETABLE (Brassica oleracea Var Sabella) IMPROVES ITS PROPERTIES AS A FUNCTIONAL FOOD(2023) Subedi, Ujjwol; Obanda, Diana; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The properties of kale as a functional food are well known. Fermentation is a process that has been shown to improve the health impacts of foods. In this study, we sought to determine how fermentation further improves or augments the functional food properties of kale. We tested six different fermentation methods which included traditional practices and inoculation with different bacterial species and compared outcomes to the unfermented control. After 16 days of fermentation, we quantified (i) selected bioactive components and (ii) anti-nutritional factors. We then determined (i) the antioxidant capacity of the whole vegetable, (ii) the microbiota composition of the vegetable, and (iii) the anti-inflammation capacity of the ethanolic extract of the vegetable. Fermentation significantly increased (i) the quantities of total polyphenols from 8.54 to 10.71 mg GAE/g (ii) sulforaphane from 960.8 ± 41.76 to 1777 ± 45.95 μg/g, and (iii) antioxidant capacity from 61.99 to 67.37 % respectively, and antinutritional factors oxalate and tannin content significantly reduced by 49 % and 29.83 % respectively. Fermented kale extract exhibited potent anti-inflammatory effects in macrophages by reducing the iNOS expression by 84.3% and TNF-α, IL-1β, and IL-6 mRNA levels by 62, 68, and 85.5 %, respectively. Fermenting kale changed the surface microbiota by reducing the population of the inflammation-inducing Proteobacteria while increasing health-promoting Firmicutes; including Lactobacillus. All fermentation methods had a beneficial impact compared to the unfermented control, but the mixed culture of L. lactis and L. acidophilus was the most effective. In summary, fermenting enhanced the health benefits of kale by increasing the concentration of total polyphenol, sulforaphane content, antioxidant capacity, anti-inflammation capacity, and reducing the quantity of anti-nutritional factors. Furthermore, it promoted the prebiotic and/or probiotic vehicle properties of the vegetable by changing the proportion of beneficial bacteria and those associated with inflammation.Item ANTICANCER ACTIVITY OF NATURAL PRODUCTS IN HUMULUS LUPULUS(HOPS) IN HUMAN COLORECTAL CANCER CELLS.(2023) Tamia, Gillian; Lee, Seong-Ho; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cancer is a major public health problem and the second-leading cause of death in the world. Colorectal cancer (CRC) is the third most diagnosed cancer in the U.S. CRC is highly associated with daily diet and eating patterns. A plant-based diet rich in phytochemicals has been known to be protective against the initiation and progression of CRC occurrence. The hop plant, a key ingredient in beer, contains a diverse form of bioactive compounds that possess biological benefits in tumorigenesis. Xanthohumol (XN), the most abundant prenylated flavonoid, has been used over the years to treat a broad range of chronic diseases such as diabetes, obesity, and cancer. Several derivatives of XN, including isoxanthohumol (IXN), 8-prenylnaringenin (8-PN), and tetrahydroxanthohumol (TXN), possess similar and greater biological benefits compared to XN. While XN's anti-cancer properties are well known, the effects of these derivatives have not been evaluated in human CRC models. Our study aimed to test the cancer-suppressive activities of these derivatives and elucidate anti-cancer mechanisms using human adenocarcinoma CRC cells. The results indicate that four hop compounds (XN, IXN, 8-PN, and TXN) significantly suppressed the proliferation of different types of human CRC cell lines. We selected TXN and XN for further studies due to their more significant and promising anti-proliferative activity compared with other forms. Flow cytometry analysis indicated that TXN and XN led to significant induction of S-phase and G2/M-phase arrest. An apoptotic assay showed a huge induction of early and late apoptosis in cells treated with TXN and XN at doses of 12 µM and 18 µM. Western blot data indicate that TXN and XN induce the cleavage of PARP and increase the expression of CHOP, IRE1α, and ATF4, indicating activation of caspase-dependent apoptosis and ER stress. In addition, a dose-dependent increase in intracellular ROS was observed in cells treated with 12 and 18 µM of TXN and XN, affecting mitochondrial dysfunction. Taken together, our current study proposes an anti-cancer mechanism by TXN and XN through their action on the induction of ROS release and mitochondrial dysfunction, ER stress, and apoptosis in human CRC cells.Item MECHANISMS CONTROLLING VOLATILE FATTY ACID AND FERMENTATION GAS PRODUCTION IN THE RUMEN(2022) Scott, Jarvis G; Kohn, Richard A; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Atmospheric methane accounts for less than approximately 16% of global anthropogenic greenhouse gas emission. However, it is significantly greater and trapping heat when compared to atmospheric CO2 on a molar lever and any reduction in atmospheric abundance in warranted. Enteric methane from ruminant species accounts for a fraction (< 30%) of the total atmospheric methane however its production also accounts for major dietary energy loss in ruminant species and affects feed efficiency and overall production. Major studies have investigated numerous feed additives and supplements with highly variable finding on the antimethanogenic property of these compounds or feeding strategies, however the findings have raised other questions regarding shifts in VFA profiles accompanying methane inhibition. Higher inclusion levels of concentrate and other nonstructural starch in the diet of ruminants have been shown to decrease methane production and shift volatile fatty acid (VFA) profiles in the rumen. Additionally, many studies have suggested that inhibiting methane production avails as a reducing equivalent to fuel the propionate producing pathway and therefore results in shift in VFA profiles in the rumen. However, very little is understood regarding how these VFA shifts come about. Microbial Kinetics and thermodynamics are physiochemical principles that can be used to study how concentrate inclusion in ruminant diets can change the substrate concentrations and ultimately lead to shifts in fermentation profile in the rumen. Substrate availability supports and/or limits the growth of microbial population in the rumen, while the accumulation of the products or reactants for major fermentation reactions dictate the profile of the VFA. Understanding the role of these physiochemical principles and ultimately the mechanisms involved with changes the profile of VFA and fermentations gas in the rumen would help researchers understand how VFA profiles are shifting during methane inhibition as well as possibly identifying a more targeted approach for inhibiting enteric methane production. Therefore, the objectives of this projects are: to develop an in vitro method to understand the basal kinetic parameters of metabolism in the rumen, to evaluate the effects of increasing forage-to-concentrate ratio on performance and change in in VFA and fermentation gas in vivo, and to test the effect of various perturbations (fermentation metabolites e.g. sodium acetate, sodium lactate etc.) on the fermentation profile of rumen fluid adjusted to different forage-to-concentrate ration. The results indicate that rumen fluid from cows on a high-concentrate diet have a greater capacity to make propionate compared to the high forages diet. The higher propionate production limits the availability of which is necessary for the synthesis of CH4. The finding also suggests that methanogenesis is process limited by substrate concentration. Finally, our studies indicate that feeding strategies targeting enzymatic activity favoring propionate production may be more beneficial than targeting methanogens in a high forage diet.Item Determinants of Food Insecurity in the League of Arab States(2022) Sheikomar, Olfat Bakur; Sahyoun, Nadine R; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background Food insecurity (FI) is widespread in the League of Arab States (LAS) due to factors including gender inequality, conflict, and political turmoil. However, limited data are available on its prevalence and determinants in that region. This dissertation aims to 1) validate the Food Insecurity Experience Scale (FIES), developed by the UN Food and Agriculture Organization, and assess the prevalence of FI in that region; 2) examine the association between FI, physical health, and mental well-being by sex and whether social support modifies this association in women; 3) examine the relationship between Palestinian live-in grandparents (GP) and the health and well-being of their grandchildren.Methods Rasch modeling was applied to the Gallup World Poll data to validate FIES in 19 countries of the region. Descriptive and logistic regression analyses were applied to data from 62,261 respondents aged 19 and over to examine determinants of FI. Logistic regression was also used to analyze the data of 2707 households and 8,034 children ages 0-17 from two surveys of Palestinian refugees. Results FIES met the Rasch assumptions indicating good internal validity. The prevalence of severe FI was 15.7% and women were at highest risk compared to men (17.6% vs. 14.1%, respectively, p<0.0001). Older age, living in rural areas, and high dependency ratio were associated with severe FI in women. High negative experience and low income were associated with severe FI, but good physical health and high positive experience with lower prevalence of severe FI. Having a live-in GP in the household was associated with grandchildren’s lower odds of experiencing an acute disease and higher odds of attending school. Conclusion FIES is a valid tool; however, cognitive testing of some items and omission of correlated ones may improve the scale. FI is highly prevalent and should be monitored to develop multi-sectoral intervention strategies. Mixed method studies are needed to better understand the relationship between grandparents and their grandchildren.Item Regulation of Mitochondrial Metabolism and Lipogenesis(2021) Surugihalli, Chaitra; Sunny, Nishanth E; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Non-alcoholic fatty liver disease is one of the most common liver disorders with a global prevalence of over 25%. Fatty liver is the most common comorbidity of insulin resistance, obesity, and type 2 diabetes mellitus. During fatty liver, nutrient overload and the associated hyperinsulinemia results in elevated circulating free fatty acids and lipid accumulation in the liver. High rates of lipid accumulation in the liver is partly attributed to high rates of lipogenesis from carbohydrates, together with dysfunctional lipid oxidation. Further, these dysfunctional metabolic networks will induce oxidative stress and inflammation. Thus, understanding the metabolic mechanisms contributing towards the etiology of fatty liver and its associated morbidities is of major interest towards developing prevention and management strategies. This dissertation utilizes a combination of in-vivo (chicken and mice) and in-vitro (isolated mitochondria) systems with stable isotope-based methodologies to study metabolic regulation.Chicken embryos utilize yolk lipids (>45%), deriving over 90% of their energy through lipid oxidation for development. However, during the last few days of incubation and immediately after hatch, there is a substantial induction of lipogenesis. Despite the hepatic lipid overload, the synergistic remodeling of hepatic metabolic networks during embryonic-to-neonatal development blunted inflammatory onset, prevented accumulation of lipotoxic intermediates, and reduced reactive oxygen species production. Elevated plasma branched-chain amino acids (BCAAs) are a characteristic of insulin resistance and are relevant in predicting T2DM. Defects in BCAA degradation networks are also evident in several tissues during insulin resistance and associated co-morbidities. Furthermore, alterations in BCAA metabolism are associated with changes in lipogenesis and mitochondrial oxidative networks. We utilize a combination of isolated mitochondrial systems and stable isotope tracers in diet-induced mouse models of fatty liver, to determine its impact on mitochondrial metabolism and lipogenesis. In summary, the dissertation highlights i) the importance of the natural but dynamic remodeling of hepatic mitochondrial metabolism and lipogenesis during the efficient embryonic-to-neonatal transition in chicken ii) the significance of BCAAs as important regulators of hepatic mitochondrial lipid metabolism. Thus, these studies provide a platform to modulate hepatic metabolic networks and utilize the embryonic-to-neonatal transition phase and dietary intervention of BCAAs as management strategies to alleviate metabolic dysfunctions.Item Effect of Air on Rumen Gas Production(2021) Rha, Rachel Youngah; Kohn, Richard A; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Ruminants may swallow air as they eat and ruminate throughout the day. However, it is unclear as to how the introduction of oxygen impacts fermentation pathways, bacteria, and yeast within this mostly anaerobic environment. Therefore, the focus of this thesis was to study air’s impact on rumen fermentation and to determine if probiotics could offset air’s impact on digestibility. An in vitro analysis of air and probiotics indicated the main effect of air decreased digestibility, the main effect of probiotics had variable effects, and probiotics had significant interactions with air. The interactions suggested yeast employing a potential alternative pathway with the introduction of oxygen. Utilizing published literature, a static and dynamic mathematical model was built to further analyze digestibility, gas composition, and uptake of oxygen within the rumen. Future studies will further develop this model with in vivo studies to further interpretation and understanding of rumen fermentation’s complex system.Item The Impacts of Branched Chain Amino Acid Supplementation on Adipocyte Function(2021) Gregory, Tabitha; Sunny, Nishanth E; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The branched chain amino acids (BCAAs) are three essential amino acids: valine, leucine, and isoleucine. Adipose tissue has high rates of BCAA degradation and this has been shown to fuel normal function. Recent literature highlights cross- talk between BCAAs, lipid metabolism, and mitochondrial dysfunction. The objective of this thesis is to determine the impact of BCAA supplementation on adipose development, morphology, and various aspects of energy metabolism including BCAA degradation and lipolysis.C57-BL6N mice were reared on either low-fat (LF), LF with 150% BCAAs (LB), high-fat (HF), or HF with 150% BCAAs (HB) diets for 12-34 weeks. Adipose tissue morphology and energetics were determined. Results demonstrated that BCAA supplementation reduced lipid storage in visceral adipose depots, lowered circulating leptin, and reduced lipid accumulation in brown adipose tissue. BCAA supplementation also induced lipolysis, which raised circulating fatty acids. These results could have implications in the treatment and prevention of metabolic diseases.