REU Projects

Adolfina Koroch

Adolfina Koroch
Project: Investigating the potential antioxidant capacity of natural extracts

Many abiotic stresses lead to the production of reactive oxygen species (ROS), which are toxic and cause damage to cellular molecules that ultimately results in oxidative stress. Plants accumulate high concentrations of chemicals that are not used for growth and development, but they provide a wide range of ecological advantages. Some of these compounds are phenolics and essential oils and can protect the plant against oxidative stress damages. REU students will investigate ethnobotanical uses of the plant using literature search, and then determine the chemical composition (total phenolics and total flavonoids) and antioxidant capacity of natural extracts. Students will correlate the antioxidant capacity, chemical composition (such as total phenolics, flavonoids, or oils) and ethnobotanical use. Students will test the hypothesis that antioxidant capacity is due to the chemical composition and will understand the plant’s ethnobotanical use.

Alexander Gosslau
Project: Effects of natural extracts on the stress response

The stress response exerted by stress proteins is a vital and prompt defense mechanism in a variety of different organisms. Stress proteins were initially termed heat shock proteins (Hsps) after the first observation of an upregulation by heat. Meanwhile, it is well established that Hsps are induced in response to a wide range of biological and physicochemical stressors, including heat shock and oxidative stress. Prominent stress proteins are represented by Hsp70, which protects the cell by binding to malfolded proteins that result from exposure to stress, thus preventing their aggregation and either helping these proteins to refold to their active state or targeting them to lysosomes for protein degradation. Plants contain different secondary metabolites demonstrated to reduce the damaging effects of environmental stress. Students will analyze the impact of plant extracts on mammalian cells exposed to heat shock and to oxidative and chemical stress. By the use of TaqMan qPCR, REU students will quantify the expression levels of Hsp70 as defense measure of plants to reduce environmental stress. By integrating the knowledge of the chemical composition, students will hypothesize the mechanisms leading to a decrease of cellular stress.

 

Christine Priano

Christine Priano
Project: Effect of natural extracts on microbial life in fresh water and marine ecosystems

Microbial organisms in fresh water and marine environments are crucial for sustaining life in these aquatic ecosystems. The physical environment is usually associated with shifts in organism abundance, activity, and diversity. Intertidal ecosystems are especially subject to frequent changes in abiotic conditions such as temperature and salinity. In a changing global environment, it is of interest to investigate disruptions at the base of ecosystems in intertidal regions where microorganisms are exposed to constant fluctuations in salinity. It is hypothesized that such fluctuations cause stresses that lead to cell damage in microbes, thereby affecting the balance of life in these ecosystems. Because natural extracts have the potential to relieve cell damage, REU students will screen microbial life in fresh water and marine environments, determine the physical conditions, analyze these microbes under stresses of salinity variation, and study the effect of natural extracts on microbes when exposed to these stresses. Students will employ standard microbiology techniques and metabolic assays for characterization and identification of bacterial strains, DNA extraction, plasmid isolation, DNA sequencing, and protein analysis.

 

Abel Navarro

Abel Navarro
Project: Use of plant polymers on nutrients and heavy metal removal

Dr. Navarro is interested in the development of natural biopolymers (e.g., tea leaves and fruit peels) from plant bio-residues with high affinities towards heavy metals and nutrients (phosphate and nitrates). Heavy metals in water are a prevalent concern in mining industries and algal blooms (eutrophication) are a problem in aquatic environments due to high concentrations of plant nutrients. Plants can absorb heavy metals, organic materials, or other pollutants due to the biological and chemical diversity of their composition. REU students will examine the capability of plant by-products in the raw and modified states to remove phosphate and nitrate ions as well as heavy metals from waters from Central Park (NYC) and evaluate their release under different experimental conditions. Students will relate these results to the chemical composition of the plant product.

 

Jose Romero

José Fernández Romero
Project: The effect of plant extracts on cell death mechanisms induced by reactive oxygen species

 

Oxidative stress can result in extensive tissue damage and is related to an imbalance in reactive oxygen species (ROS) and antioxidant defenses. It has been recently suggested that ROS play an important role in apoptosis. Our REU project will focus on studying the effect of ROS on apoptosis by looking at the upregulation or downregulation of host factors that trigger this response. We will also study how antioxidants from plant extracts can suppress or delay apoptosis. For this purpose, the students will learn basic cell culture techniques as well as cytotoxicity assays, immunofluorescence and molecular biology techniques.

 

Lalitha Jayant

Lalitha Jayant
Project: Effect of natural extracts on viability of sea urchin eggs

Harvested sea urchin eggs disintegrate within 24 hours and become heavily infested with a specific species of protists. Preliminary results have shown that the eggs of sea urchin Lytechinus variegatus disintegrate within 24 hours in regular sea water also under laboratory conditions. Current focus of this project is to optimize conditions to prolong the shelf life of sea urchin eggs. Students will test the hypothesis that eggs are disintegrating either due to oxidative stress or due to the presence of protists. In this project REU students will artificially spawn sea urchins to obtain eggs. Eggs will be exposed to different natural plant extracts that exhibit anti-oxidative and anti-microbial properties. Effect of these extracts on viability of sea urchin eggs will be studied by counting eggs at various intervals for at least a week. Students will also examine how these extracts affect the survival and proliferation of protists.

 

peter nguyen

Peter Nguyen
Project: Microbiota and their effects on degradation of a black tea extract

The gut microbiota, a variety of different bacterial strains, play a key role in modulating the biological activities of natural extracts. Black tea is well known for its beneficial health effects. Theaflavins are the major bioactives in black tea. A mystery in tea research has been the discrepancy between the well-established bioactivity on the one hand and poor bioavailability on the other. This is evident by the failure or detection of theaflavins in blood or urine. During digestion in the stomach and small intestine (duodenum), bioconversion of theaflavins may lead to smaller metabolites responsible for the bioactivity of black tea. REU students will work with a black tea extract enriched with theaflavins. They will apply the black tea extract to common bacterial strains from stomach and duodenum, including Lactobacillus acidophilus, Bacteroides fragilis, Enterococcus faecalis, and Escherichia coli. Students will also treat two cell lines derived from stomach and duodenum (e.g., AGS and HuTu 80 cells). After harvesting and extraction, students will compare and evaluate the chromatographs derived from bacteria and intestinal cells by the use of paper chromatography. Students will learn how to identify smaller metabolites and relate these results to the generation of black tea metabolites by bioconversion of theaflavins.

 

Brian Rafferty

Brian Rafferty
Project: Use of natural extracts to examine the regulation of stress related signaling pathways

The stress response in mammalian cells is the result of the integration of several signaling pathways leading to the regulation of the transcription factor NF-κB. Stimulation of cells with various inflammatory factors lead to the production of IL-6 and IL-8 in a NF-κB dependent manner. Many studies have examined ways to mitigate these pro-inflammatory responses through the modulation of secondary pathways that can counteract the effects of NF-κB. REU students will screen natural products on mammalian cell lines to identify those that exhibit alterations in the normal cellular response to inflammatory stimuli through examination of IL-6 and IL-8 protein levels (by ELISAs) and mRNA levels (by TaqMan qPCR). To determine which pathway(s) the natural extract is utilizing to control the inflammatory response, students will use the natural extracts in combination with specific chemical inhibitors of various pathways (JAK/STAT, PI3K, JNK, ERK). Pathway specific targets will be analyzed at both the protein level through Western blotting and gene expression by TaqMan qPCR. This study will provide students with an in-depth examination of the mechanistic effects of natural extracts on signal transduction in a mammalian cell system.