Browsing by Author "Elhaj, Joanna"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Effects of metals on probiotic Lactobacillus(2020-09-29) Elhaj, JoannaThe gastrointestinal tract (GIT) contains trillions of microorganisms with over 1000 bacterial species, including probiotic bacteria. Probiotics are live microorganisms with positive effects on the host if administered in sufficient amounts. Gut microbes, including [HU1] probiotic species, help build the immune system, protect against pathogens, and synthesize nutrients. The abundance of gut microbes can be affected by changes such as diet, antibiotics, diseases, or infection. Lactobacilli are mostly found in the small intestine and used in probiotic formulations. Intestinal Lactobacillus species can be affected by changes in dietary essential metals, including calcium and zinc. Many Lactobacilli can form biofilm to colonize the GIT, subsequently promoting human health and effectiveness of probiotics. However, there are few studies on the metal effects on their biofilm formation. Here, we focused on the effect of zinc and calcium on biofilm formation of L. plantarum and L. acidophilus which have known mucus-binding domains that can facilitate biofilm formation and possibly, metal-binding. L. acidophilus has the S-layer proteins and L. plantarum have mannose-binding properties that can help them adhere to the GIT and aggregate to form biofilm. To determine the extent to which metals can affect biofilm formation, we examined their biofilm formation under varied metal concentrations using crystal violet (CV) and colony-forming unit (CFU) count assays. We detected an increase in biofilm formation when the biofilm was grown under increasing zinc and calcium concentration. Zinc promotes the viability of both Lactobacillus species, while calcium induced their biofilm to grow faster, especially to L. acidophilus.Item Proteomic Analysis of Lactobacillus species(2021-04-01) Elhaj, Joanna; Huynh, UyenThe gut microbiota is important to human health as it provides pathogen protection and strengthens immunity. Probiotics are live microorganisms that confer positive effects on the human host, including strengthening the intestinal barrier and modulating immune response. Lactobacillus species are used in probiotic formulations and despite their relatively low abundance in the distal human gut, they are often positively or negatively correlated with intestinal diseases and infections. Lactobacilli are impacted by changes in dietary metals, like iron and zinc. Iron deficiency can promote Lactobacilli growth, zinc deficiency correlates to damaged immune systems, and zinc overload correlates with increased susceptibility to infections. Lactobacilli have low iron and high manganese needs for growth. However, the roles of these metals in metabolism and function of Lactobacilli in the gut microbiota are unclear. This study is a computational proteomic analysis aiming to identify roles of metals in Lactobacilli by analyzing metal-associated proteins. We quantified and categorized metal-associated proteins in several intestinal Lactobacillus species based on annotated proteomes pooled from the UniProtKB database. Results show at least 15% of Lactobacilli proteins are metal-associated, with zinc, manganese, and iron most abundant. Metalloproteomes of Lactobacilli are more extensive and diverse than currently recognized. Compared to well-studied bacteria like E. coli K-12, there are less proteins annotated on UniProtKB for Lactobacilli. According to our results, an average of 20.4% of proteins in the Lactobacillus bacteria are uncharacterized. Defining and characterizing the metalloproteomes of probiotics inform us which metals play important roles in their ability to colonize the host.