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Home > Characterization of Antimicrobial Compounds Producing Lactic Acid Bacteria from Domestic Mammals and Their Application As Probiotic or Food Preservative

Characterization of Antimicrobial Compounds Producing Lactic Acid Bacteria from Domestic Mammals and Their Application As Probiotic or Food Preservative

Thesis Info

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Author

Ayesha

Program

PhD

Institute

University of the Punjab

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Microbiology

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/10533/1/Ayesha_Microbio_2019_UoPunjab_PRR.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725679089

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Foodborne pathogens are a major threat to human health and the food industry. These bacteria cause spoilage of food and diseases on consumption. Moreover, the emergence of antibiotic resistance in clinically important strains of bacteria has led to the search for alternative solutions. Lactic Acid Bacteria (LAB) are well known for their antagonistic potential against closely related microbial species. The antagonistic activity is strain specific. LAB and their inhibitory compounds are gaining attention as they are declared GRAS status by FDA and have been utilized as probiotics and substitute of food preservatives. LAB are cosmopolitan and are found in dairy fermented products, soil and intestine. Previous studies were based on their isolation from dairy products but intestinal microbiota of domestic mammals is a less explored area. Our current study was focused on isolation and characterization of LAB strain from intestinal microbiota with antagonistic activity against important clinical and foodborne pathogens. The probiotic properties of LAB strains were also analyzed. We explored their metabolites as food preservative and determine physiochemical characteristics of the active component. Moreover, we also tried to partially purify the active component and determine its influence on the cell wall of pathogen and detection of the bacteriocin encoding gene in one of the potent strain. Finally prophylactic potential of most prominent strain using Listeria monocytogenes infection model in mouse. A total of sixty three (63) strains were isolated from the intestine of 7 domestic mammals. Out of which 48 trains presented acid production property and were considered lactic acid bacteria. Out of 48 only 22 strains could exhibit antimicrobial activity against both gram positive and negative bacteria. The indicator strains used in the study include Staphylococcus aureus, Clostridium perfringens, Listeria monocytogenes, Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae and Proteus mirabilis. Six strains were selected on the basis of high antagonistic potential presented against at least one gram positive and one gram negative target strain used in the study. The selected strains were identified on the basis of 16S rRNA gene sequencing and accession number was obtained from NCBI Genebank. They are identified as Lactobacillus brevis MF179529, Enterococcus ratti MF183967, Enterococcus sp. MH734728, () Enterococcus sp. MH734729, Enterococcus durans MF179526, Pediococcus sp. MH734727. These strains were initially named as H, R, A, C, O, P respectively. Probiotic potential of the strains was evaluated on the basis of tolerance to NaCl (1-8%), bile salt (0.5-2%), pH (2-6), temperatures (35-50%), antibiotic resistance and non-hemolytic nature towards RBCs. Our results indicated that 6 strains had probiotic potential and were safe for utilization as food preservative. Among all strain Lactobacillus brevis MF179529 exhibited higher probiotic potential being resistant to grow at pH2, 50°C temperature, 3% bile salt and non-hemolytic nature. Furthermore, it exhibited 85% hydrophobicity and 69% antibiotic sensitivity making it the most promising probiotic candidate. To analyze the potential of the active component of CFS (Cell Free Supernatant) of selected strain against selected pathogen tests were performed. The comparison of growth kinetics of foodborne pathogens (L. monocytogenes, C. perfringens, S. enteritidis and E. coli) in the presence of 20% CFS of our six LAB strains showed inhibition of pathogen in food products. Our LAB strains produced active metabolites in growth medium and their CFS was effective against selected foodborne pathogens and is recommended for further studies for its use as food preservative. Inhibitory activity among strains varied but CFS of Enterococcus ratti MF183967 was appeared to be more active against L. monocytogenes. The oral administration of Lactobacillus brevis MF179529 provides the protective effect to the Listeria monocytogenes infected in mice. L. brevis MF179529 reduces L. monocytogenes load in liver, spleen and intestine and also maintain intestinal microbial equilibrium. Further studies are needed to best understand the mechanisms by which this microorganism promotes resistance against infectious diseases. Chemical nature of CFS was determined by treatment with enzymes, surfactant, pH and temperatures. The results indicate the proteinaceous nature of the active compounds as their activity diminished after treatment with protinase K and pepsin. CFS of all strain remained active at pH4-10, their inhibitory activity remained stable up to 100°C. SDS-PAGE analysis of the partially purified fraction of CFS of E. ratti MF183967 indicated the presence of two peptide bands of 20 and 30KDa, out of which 20KDa showed antimicrobial activity against Methicillin resistant Staphylococcus aureus (MRSA). Mode of action of the active component of E. ratti on the cell wall of MRSA revealed its rupturing that was observed under scanning electron microscope (SEM). Presence of enterocin coding genes entp and entL50A also strengthen the production of enterocin like inhibitory substance, by E. ratti MF183967 and that is applicable in food preservation. It is concluded that our six strains possess high inhibitory potential against spoilage and clinical pathogens. E. ratti MF183967 produce 20KDa peptide which is responsible for antimicrobial activity against MRSA. Presence of enterocin coding genes entp and entL50A also strengthen the production of enterocin like inhibitory substance, by E. ratti MF183967. In addition, L. brevis MF179529 ingestion has health promoting capacities and a good candidate to be employed as a probiotic against listeria infection.
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ڈاکٹر ضیاء الدین

ڈاکٹر ضیاء الدین مرحوم
افسوس ہے کہ گزشتہ ۲۴؍ دسمبر ۱۹۴۰؁ء کو ڈاکٹر سر ضیاء الدین مرحوم نے بعارضہ فالج لندن میں انتقال کیا، مرحوم اپنے علمی کمال میں ہندوستان کے مشاہیر میں تھے، وہ تعلیم کے ماہر اور ریاضیات کے ممتاز فاضل تھے، انھوں نے اپنی تعلیم کے زمانہ میں ان فنون میں ہندوستان اور یورپ کی درسگاہوں میں جو امتیازات حاصل کئے، وہ اس دور میں کم ہندوستانیوں کو حاصل ہوئے تھے، چند دنوں جامعہ ازہر میں بھی رہے تھے، اس لئے عربی سے بھی کچھ واقف تھے، ان کی پوری زندگی علم و تعلیم کی خدمت میں گزری اور وہ نصف صدی سے زیادہ کسی نہ کسی حیثیت سے مدرسۃ العلوم اور اس کے بعد مسلم یونیورسٹی سے وابستہ رہے، کئی مرتبہ وائس چانسلر ہوئے، ابھی تھوڑے دن ہوئے کہ اس عہدہ سے سبکدوش ہوئے تھے، برسوں مجلس مقننہ کے ممبر رہے، مالیات میں ان کی رائے اور مشوروں کو خاص اہمیت حاصل تھی، ان کو اس زمانہ کے بڑے سے بڑے اعزاز حاصل ہوئے، جن سے یونیورسٹی کو بھی فوائد پہنچے اور ان کے دور میں اس کو بڑی ترقی ہوئی، ان کا آخری کارنامہ میڈیکل کالج کا قیام ہے، چند مہینے ہوئے جدید تعلیمی نظام کے مطالعہ کے لئے یورپ اور امریکہ گئے تھے، کہ لندن میں پیام اجل آپہنچا۔
مرحوم اس دور کی پیداوار تھے، جب مسلمانوں پر مغربی تمدن مسلط تھا، اور اس کا سب سے بڑا مرکز علی گڑھ تھا، لیکن انھوں نے اس کا بہت کم اثر قبول کیا، اب تو ضعیفی کی عمر تھی، وہ ہر زمانہ میں نہ صرف عقیدے بلکہ ظاہری وضع قطع میں بھی مسلمان رہے، ان کی زندگی بڑی سادہ اور بے تکلف تھی، ان کی سادگی میں ایک صاحبِ کمال کی شانِ بے نیازی پائی جاتی تھی، شخصی طور پر بھی ان...

A Videogrammetric Analysis of On Peak/Off Peak Traffic Density: A Case of Board Bazaar Peshawar

The increasing population is a growing issue in densely populated cities, which leads to an increase in transportation services. In this paper travel time delay due to stationary bottleneck was observed throughout the week in one of the densely populated cities of Pakistan i.e. Peshawar. Videogrammetry was implemented to obtain the recorded frames through the various days of the week. The recorded frames were then statistically analyzed to identify the travel delays in Board Bazaar Peshawar at a stationary bottleneck using SPSS and Statgraphics Software. The statistical analysis revealed a direct proportionality between traffic density and travel time, whereas an inverse proportionality was identified between traffic speed and traffic density. A high traffic density was observed on working days, whereas on the non-working days a reduced traffic density was observed. This study recommends a predictive target lane vehicular guidance system for a smooth traffic flow.

Comparative Investigation of Natural and Synthetic Iron Chelating Agents in Experimental Animals.

Iron is vital and an essential requirement for most plants and animals to maintain the homeostasis of iron through a series of chemical reactions.Normally, the amount of iron in the human body is closely regulated, with a balance being achieved between the amount lost and that absorbed from the diet. Regular blood transfusions in thalassemia and other chronic refractory anemia can result due to the excessive iron deposition in tissues and organs. The regulation of this vital but potentially toxic substance, when present in excessive amounts, can negatively affect several physiological processes in the human body. The present study was conducted to evaluate the compartive efficancy of some natural and synthetic chelating agents towards chelation of iron in the experimental animals. Medicinal plants including amrood (Psidium guajava), green tea (Camella sinesis), turmeric (Curcuma longa) and khatti (Citrus aurentifolia) were evaluated for their natural chelating potential against iron overload in the experimental animals.The extracts from the selected medicinal plants were evaluated for their antioxidant activity, antimicrobial activity, cytotoxicity,along with GC-MS and FTIR phytochemicals profiling. Iron overload was induced by administration of iron sulphate and IROSE (iron sucrose) to the experimental animals. The experiments were conduted to evaluate selective parameters such as serum ferritin, immune status and liver enzymes etc., along with histopathological status of different body organs like liver, kidney and spleen of the model animals. Iron overload caused tissue damage in the experimental animals and also increased the concentration level of biochemical parameters in the serum. The plant derived natural chelating agents/extracts, administrated orally, restored the biochemical parametres and tissue injury of different soft organs of the the experiomnetal animals leading towards the normal state. It can be concluded from the findings of the present study that the tested medicinal plants had appreciable chelation ability to excrete the excess iron from different organs of the thalassaimic patients and thus can be explored as a sustainable source for isolation of natural iron chelating agents to replace the synthetic ones.