Dr. Jayalekshmi H. currently serves as Assistant Professor at the School of Biotechnology. She received her M. Phil. in Microbiology, Bharathidasan University, Tamil Nadu, 2007. She was also conferred M. Sc. Microbiology, Kasturba Medical College, Manipal University, Manipal in 1999.


  • Ph. D., Amrita Vishwa Vidyapeetham
  • M. Phil. (Microbiology), Bharathidasan University, Tamil Nadu.
  • M. Sc. (Medical Microbiology), Kasturba Medical College, Manipal University, Karnataka
  • B. Sc. (Zoology), Kerala University, Kerala

Professional Work Experience

  • Senior Lecturer in Amrita School of Biotechnology
  • Lecturer in Amrita School of Biotechnology
  • Senior Research Fellow (CSIR funded project) in Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok, Sikkim.
  • Senior Research Fellow (ICAR funded project), Kerala Veterinary and Animal Science University, Thrissur, Kerala.
  • Microbiologist, Amrita Institute of Medical Sciences, Kochi, Kerala.


Research Interest 

  • Host pathogen interaction
  • Microbial quorum sensing
  • Microbial Biofilm
  • Antibiotic tolerance and persister cell formation
  • Compacting Antimicrobial resistance

Research Lab Associated



Publication Type: Conference Proceedings

Year of Publication Title


Jayalekshmi H., “Essential oils modulate antibiotic mediated persister cell formation of P. aeruginosa”, International Webinar on Phytochemistry 2020’ organized by Kerala Academy of Sciences. 2020.


Jayalekshmi H., “Combinatorial effect of garlic essential oil and Tetracycline against P. aeruginosa biofilm”, Proceedings of Biospectrum -2019; International Conference on Advances in Food and Industrial Biotechnology. 2019.


Jayalekshmi H., “Quorum Sensing Inhibitors Modulate Persister Cell Formation of Pseudomonas Aeruginosa”, Proceedings of 27th Swadeshi Science Congress. 2017. 2017.


Jayalekshmi H., “Preparation and Characterisation of Clove Bud Essential Oil Nanoemulsion : Investigation of its Antibiofilm Activity”, NextGen Genomics, Biology, Bioinformatics and Technologies (NGBT) Conference. 2016.


Jayalekshmi H., “Combinatorial Effect of D-amino Acids and Tetracycline Against P. Aeruginosa Biofilm”, Kerala Science congress . 2015. 2015.


Jayalekshmi H., Geeta Kumar, and Dr. Bipin G. Nair, “Antibiofilm Activity of Biosurfactants from Bacterial Strains Isolated from Oil Contaminated Soil and Sewage.”, International conference-NHBT 2015. 2015.[Abstract]

Biosurfactants are surface active molecules produced by various organisms, which have beneficial in structural diversity, low toxicity and biodegradability. These properties makes these compounds for a variety of potential applications, including cosmetics– pharmaceutical formulations, agricultural, food industry, oil recovery and environment protection technology. Furthermore, the biological properties of biosurfactants have also augment interest of industrial application. Biosurfactants are grouped into three categories of origin: microbial derived, animal-derived and plant-derived biosurfactants. In this study it is possible to isolate two bacterial strains which produce biosurfactants, from two very cheaper resources - oil contaminated soil and sewage water. The bacterial strains were tested for the ability to produce biosurfactants and screened for biosurfactant activity by oil displacement method. The highest biosurfactant producing strains were selected and identified by microscopic appearance and biochemical activities. The extracted biosurfactant’s emulsification activities were compared with synthetic surfactants. Simultaneously the biosurfactant produced by these strains were tested for its antibiofilm activity against various pathogenic microbes and found to have significant antibiofilm activity. The beneficial property of  biosurfactant production  make the strains an efficient bioremediation tool for various environmental application and represent greater significance in future biomedical applications.

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Jayalekshmi H., “Effect of Mangroves Extracts on Quorum Sensing and Biofilm Formation in S.aureus and P.aeruginosa.”, Amrita Bioquest. Kollam,Kerala, 2013.


M. Dhaneesha, D. Pai, A., and Jayalekshmi H., “Screening of Dietary Substances: New Blockade Strategy on Quorum Sensing. ”, 98th Indian Science Congress . SRM University, Chennai, 2011.


Jayalekshmi H., Sree, P. D., and Nair, B. G., “Effect of Plant Essential Oils on Biofilm Formation and Adherence of Multidrug Resistant Staphylococcus aureus.”, Proceedings of International Conference on New Horizons in Biotechnology (NHBT-2011). SRM University, Chennai , 2011.


Jayalekshmi H., “Effect of Clove Bud Essential Oil on Quorum Sensing Virulence Factors of P.aeruginosa. ”, BG.International Conference on New Horizons in Biotechnology, . Thiruvananthapuram,Kerala, 2011.


Jayalekshmi H., S, D., A, C., M, M., and DM, V., “Effect of Chronic Ethanol Administration on Testicular Antioxidant System and Steriodegic Enzyme Activity in Rats and its Reversal with Ascorbic Acid”, National conference of the Association of Physiologists & Pharmacologists of India. Kasturba Medical College, Mangalore, 2008.

Publication Type: Journal Article

Year of Publication Title


Jayalekshmi H., Omanakuttan, A., Menon, N. D., Muralidharan Vanuopadath, Nair, S. Sadasivan, Corriden, R., Nair, B. G., Nizet, V., and Dr. Geetha Kumar, “Clove Bud Oil Modulates Pathogenicity Phenotypes of the Opportunistic Human Pathogen Pseudomonas aeruginosa.”, Scientific reports, vol. 8, no. 1, p. 3437, 2018.[Abstract]

Earlier studies from our laboratory have demonstrated that clove bud oil (CBO) attenuates expression of certain virulence factors of Pseudomonas aeruginosa PAO1. Here, we probe more deeply into the effect of CBO on four pseudomonal proteases - elastase A, elastase B, protease IV and alkaline protease - each known to play key roles in disease pathogenesis. CBO inhibited the activity of these proteases present in the bacterial culture supernatant. Zymography studies indicated that these proteases can activate host matrix metalloproteases (MMPs) to establish infection, through conversion of pro-MMP-2 to active MMP-2. PAO1 is a predominant pathogen in burn wound infections and we show the modulatory effect of CBO on MMPs in an in vitro model of burn injury. Furthermore, CBO induced dose-dependent neutrophil extracellular trap formation in human neutrophils. CBO also increased the survival of C. elegans infected with PAO1, establishing an anti-infective role in a whole animal model of pathogenesis. LC-MS/MS analysis indicated that CBO treatment elicited a significant reduction of signalling molecules (Acyl-Homoserine-Lactone) involved in quorum sensing regulation. Our observations demonstrate that CBO attenuates key virulence mechanisms of this important human pathogen, while concomitantly enhancing host innate immunomodulatory functions, with potential implications for topical therapy against antibiotic-resistant infections.

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Jayalekshmi H., Norin Mary G Victus, R. Anoop, T. M. Sarath, Sajin Sali, C. .Harikrishnan, N. Kaushik, Dr. Geetha Kumar, and Dr. Bipin G. Nair, “Combinatorial effect of d-amino acids and tetracycline against pseudomonas aeruginosa biofilm”, International Journal of Pharmacy and Pharmaceutical Sciences, vol. 8, no. 11, pp. 216-220., 2016.[Abstract]

Objective: The present study attempted to evaluate the anti-biofilm activity of D-amino acids (D-AAs) on Pseudomonas aeruginosa and determine if the combination of D-AAs with tetracycline enhances the anti-biofilm activity in vitro and ex vivo. Methods: Different D-AAs were tested for antibiofilm activity against wild type P. aeruginosa PAO1 and two multidrug resistant P. aeruginosa clinical strains in the presence of sub inhibitory concentrations of tetracycline using crystal violet microtitre plate assay. Results were further validated using in vitro wound dressing and ex vivo porcine skin models followed by cytotoxicity and hemocompatibility studies. Results : D-tryptophan (5 mmol) showed 61 % reduction in biofilm formation of P. aeruginosa . Interestingly combinatorial effect of 5 mmol D-tryptophan and 0.5 minimum inhibitory concentration (MIC) (7.5µg/ml) tetracycline showed 90% reduction in biofilm formation. 5 mmol D-methionine shows 28 % reduction and combination with tetracycline shows 41% reduction in biofilm formation of P. aeruginosa . D-leucine and D-tyrosine alone or in combination with tetracycline did not show significant anti-biofilm activity. D tryptophan-tetracycline combination could reduce 80 % and 77 % reduction in biofilm formation in two multi drug resistant P. aeruginosa clinical strains. D-tryptophan-tetracycline-combination could also reduce 76% and 66% reduction in biofilm formation in wound dressing model and porcine skin explant respectively. The cytotoxicity and hemocompatibility studies did not show significant toxicity when this combination was used. Conclusion: The results established the potential therapeutic application of D-tryptophan alone or in combination with tetracycline for treating biofilm associated clinical problems caused by P. aeruginosa

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PDF iconcombinatorial-effect-of-d-aminoacids-and-tetracycline-against-pseudomonas-aeruginosa-biofilm-21september2016.pdf


Jayalekshmi H., A. Omanakuttan, N. Pandurangan, V. S. Vargis, M. Maneesh, Dr. Bipin G. Nair, and Dr. Geetha Kumar, “Clove Bud Oil Reduces Kynurenine and Inhibits pqs A Gene Expression in P. Aeruginosa”, Applied Microbiology and Biotechnology, vol. 100, no. 8, pp. 3681-3692, 2016.[Abstract]

Quorum sensing (QS), a communication system involved in virulence of pathogenic bacteria like Pseudomonas aeruginosa is a promising target to combat multiple drug resistance. In vitro studies using clove bud oil (CBO) in P. aeruginosa revealed a concentration dependent attenuation of a variety of virulence factors including motility, extracellular DNA, exopolysaccharides and pigment production. Furthermore, treatment with CBO demonstrated a distinct dose-dependent reduction in biofilm formation as well as promoting dispersion of already formed biofilm, observations that were also supported by porcine skin ex vivo studies. Expression studies of genes involved in signalling systems of P. aeruginosa indicated a specific decrease in transcription of pqsA, but not in the lasI or rhlI levels. Additionally, the expression of vfr and gacA genes, involved in regulation, was also not affected by CBO treatment. CBO also influenced the PQS signalling pathway by decreasing the levels of kynurenine, an effect which was reversed by the addition of exogenous kynurenine. Though the synthesis of the signalling molecules of the Las and Rhl pathways was not affected by CBO, their activity was significantly affected, as observed by decrease in levels of their various effectors. Molecular modelling studies demonstrated that eugenol, the major component of CBO, favourably binds to the QS receptor by hydrophobic interactions as well as by hydrogen bonding with Arg61 and Tyr41 which are key amino acid residues of the LasR receptor. These results thus elucidate the molecular mechanism underlying the action of CBO and provide the basis for the identification of an attractive QS inhibitor. © 2016 Springer-Verlag Berlin Heidelberg

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M. Mailankot, Kunnath, A. P., Jayalekshmi H., Koduru, B., and Valsalan, R., “Radio Frequency Electromagnetic Radiation (RF-EMR) from GSM (0.9/1.8 GHz) Mobile Phones Induces Oxidative Stress and Reduces Sperm Motility in Rats”, Clinics, vol. 64, pp. 561–565, 2009.[Abstract]

Mobile phones have become indispensable in the daily lives of men and women around the globe. As cell phone use has become more widespread, concerns have mounted regarding the potentially harmful effects of RF-EMR from these devices. 
OBJECTIVE: The present study was designed to evaluate the effects of RF-EMR from mobile phones on free radical metabolism and sperm quality More »»


M. Mailankot, Jayalekshmi H., Chakrabarti, A., Alang, N., and Vasudevan, D. M., “Effect of Alpha-Tocopherol Supplementation on Renal Oxidative Stress and Na+/K+-Adenosine Triphosphatase in Ethanol Treated Wistar Rats.”, Indian journal of experimental biology, vol. 47, pp. 608–610, 2009.[Abstract]

Ethanol intoxication resulted in high extent of lipid peroxidation, and reduction in antioxidant defenses (decreased GSH, GSH/GSSG ratio, and catalase, SOD and GPx activities) and (Na+/K+)-ATPase activity in kidney. Alpha-tocopherol treatment effectively protected kidney from ethanol induced oxidative challenge and improved renal (Na+/K+)-ATPase activity. Ethanol induced oxidative stress in the kidney and decreased (Na+/K+)-ATPase activity could be reversed by treatment with ascorbic acid. More »»


M. Maneesh and Jayalekshmi H., “Role of Reactive Oxygen Species and Antioxidants on Pathophysiology of Male Reproduction”, Indian Journal of Clinical Biochemistry, vol. 21, pp. 80–89, 2006.[Abstract]

The excessive generation of reactive oxygen species (ROS) by abnormal spermatozoa and contaminating leukocytes has been defined as one of the few etiologies for male infertility. Administration of antioxidants in patients with ‘male factor’ infertility has begun to attract considerable interest. The main difficulty of such an approach is our incomplete understanding of the role of free radicals in normal and abnormal sperm function leading to male infertility. Mammalian spermatozoa membranes are very sensitive to free radical induced damage mediated by lipid peroxidation, as they are rich in polyunsaturated fatty acids. Limited endogenous mechanisms exist to reverse these damages. ROS attacks the fluidity of the sperm plasma membrane and the integrity of DNA in the sperm nucleus. ROS induced DNA damage accelerate the germ cell apoptosis. Unfortunately spermatozoa are unable to repair the damage induced by excessive ROS as they lack the cytoplasmic enzymes required to accomplish the repair. Assessment of such oxidative stress status (OSS) may help in the medical treatment. Treatment strategies must be directed toward lowering of ROS levels to keep only a small amount necessary to maintain normal cell function. More »»


M. Maneesh and Jayalekshmi H., “Antioxidants as Therapeutical Agents for Male Infertility. ”, Journal International Medical Sciences Academy , 2006.


M. Maneesh, Jayalekshmi H., Singh, T. A., and Chakrabarti, A., “Impaired Hypothalamic-Pituitary-Gonadal Axis Function In Men With Diabetes Mellitus”, Indian journal of clinical biochemistry, vol. 21, pp. 165–168, 2006.[Abstract]

In view of association of diabetes mellitus and male infertility, present study was designed to investigate the functional status of hypothalamic pituitary gonadal (HPG) axis in diabetic men. Thirty-five diabetic men (BMI 22.24±0.21) in the age group 20–40 (30.6±4.7) years were selected. Twenty-five healthy men (BMI 23.85±0.25), in the same age group (29.5±4.8) served as control. Blood samples were collected for hormonal and biochemical estimations. Diabetic men had significantly low serum testosterone with low LH and FSH, hypercholesterolemia, hypertriglyceridemia, hypoalbuminemia and increased oxidative stress. Low serum testosterone in diabetic men was accompanied by low LH and FSH; the inability of the pituitary gland to respond appropriately to a decline in testosterone implying central effect of high serum glucose on the interaction between the nervous and endocrine system. Nutritional deficiency, increased oxidative stress and increased aromatase activity due to excessive body fat might have also contributed to low serum testosterone. More »»


M. Maneesh, Jayalekshmi H., Dutta, S., Chakrabarti, A., and Dr. Damodaran Vasudevan, “Effect of Chronic Ethanol Administration on Testicular Antioxidant System and Steroidogenic Enzyme Activity in Ratsc”, Indian J Exp Biol, vol. 43, pp. 445–449, 2005.[Abstract]

In order to find out the effect of chronic ethanol administration on testicular antioxidant system and steroidogenic enzyme activity, male rats fed with ethanol 1.6g/kg body weight per day for four weeks were studied. Besides a drastic reduction in body and testis weight, there was decrease in ascorbic acid, reduced glutathione and activities of superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase in the testicular tissue of the treated animals. Simultaneously, there was increase in lipid peroxidation and glutathione S-transferase activity. Activities of 3β-hydroxy steroid dehydrogenase and 17β-hydroxy steroid dehydrogenase were also found decreased in the treated animals. The results indicate that chronic ethanol administration resulted in increase in oxidative stress and decrease in the activities of steroidogenic enzymes in the rat testes. More »»


M. Maneesh, Jayalekshmi H., Dutta, S., Chakrabarti, A., and Dr. Damodaran Vasudevan, “Role of Oxidative Stress in Ethanol Induced Germ Cell Apoptosis—an Experimental Study in Rats”, Indian Journal of Clinical Biochemistry, vol. 20, pp. 62–67, 2005.[Abstract]

The study was undertaken to evaluate the possible involvement of oxidative stress in the pathogenesis of ethanol induced testicular atrophy in rats. Adult male rats were orally administered ethanol at a dose of 1.6 g/kg body weight/day for four weeks. Twenty-four hours after the last treatment the rats were sacrificed using anesthetic ether. Testes were removed and weighed. Apoptosis was studied by using the Feulgen reaction on 5 μ thin paraffin sections of testis. Testicular homogenate was prepared and centrifuged. The supernatant was used for the estimation of extent of lipid peroxidation and antioxidant defense status. There was significant reduction in body weight: and in testicular weight and diameter in ethanol treated rats. Extent of germ cell apoptosis was significantly high in ethanol treated rats. Ethanol treated rats showed significantly high tissue TBARS level and glutathione S-transferase activity; and low tissue ascorbic acid, reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities. Chronic ethanol administration resulted in high oxidative stress in the testes either due to increased extent of lipid peroxidation or due to decreased antioxidant defenses, and thereby induces germ cell apoptosis leading to testicular atrophy.

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M. Maneesh, Jayalekshmi H., Suma, T., Chatterjee, S., Chakrabarti, A., and Singh, T. A., “Evidence for Oxidative Stress in Osteoarthritis”, Indian journal of clinical Biochemistry, vol. 20, pp. 129–130, 2005.[Abstract]

Evidence of increased oxidative stress in patients of osteoarthritis in comparison with healthy control subjects was investigated by measuring the thiobarbituric acid reactive substances (TBARS), vitamin C, reduced glutathione (GSH) and the activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in erythrocytes. It was observed that osteoarthritis patients were more susceptible to oxidative damage than controls as evident from increased TBARS and decreased ascorbic acid, GSH, catalase and GPx in erythrocytes. Significant increase in SOD activity found in patients might be an adaptive response. With the understanding of the role of antioxidants in arthritis, it is becoming increasingly clear that these agents seem to be beneficial in osteoarthritis. More »»


M. Maneesh and Jayalekshmi H., “Effect of Ascorbic Acid, Alpha-Tocopherol, Lecithin and L-ornithine-L-aspartate on Ethanol Induced Hypoproteinemia and Hyperlipidemia in Rats”, Indian journal of physiology and pharmacology, vol. 49, p. 422, 2005.[Abstract]

We studied effect of exogenous ascorbic acid, α-tocopherol,lecithin and L-ornithine-L-aspartate on serum lipids and proteins inexperimental hepatotoxic Wistar rats. Eleven groups (n = 6) of animals were used. Hepatotoxicity was induced by administering ethanol (1.6g/kg/day) for 28 days. Both preventive and curative options were studied.Percentage increase in body weight was significantly lower in ethanol treated rats Ethanol significantly (P<0.05) increased cholesterol, triglycerides and LDL, and decreased protein, albumin and A: G ratio in serum. Ascorbic acid, α-tocopherol, lecithin and L-ornithine-L-aspartate exhibited an ability to counteract the alcohol-induced changes in the body weight and biochemical parameters in preventive and therapeutic models in varying degree. Antioxidants showed better effect. More »»

Participation in Conferences and Workshops

i plant workshop,Amrita School of Biotechnology,Amritapuri,Kollam,Kerala. August 2014
Workshop on Introduction to research methodology-conducted by IIT Bombay -Amrita School of Engineering,Amritapuri,Kerala June 2012
Workshop on Basic Concepts in Modern Biology ,Amrita School of Biotechnology,Amritapuri,Kerala December 2006
Training workshop on AIDS,Kasturba Medical College,Manipal,Manipal University,Karnataka December 1998
XXII National congress of Indian association of Medical Microbiologists.Kasturba Medical College,Manipal,Manipal University,Karnataka. November 1998
Workshop on Rapid diagnostic techniques in Clinical microbiology with special emphasis to HIV and Tuberculosis,Kasturba Medical College,Manipal,Manipal University,Karnataka. November 1998

PG Dissertations Guided

  • Modulation of Ciprofloxacin mediated persister cell formation in Pseudomonas aeruginosa with Essential oils (2020).
  • Antimicrobial and Anti-biofilm Activity of Essential oils against Acinetobacter baumannii- An In vitro study (2020).
  • Anti-virulence activity of furfural derivatives and Butyl isothiocyanate (2019).
  • Link between Bacterial infection and Cancer: Modulation of host cell Gene expression by Pasteurella multocida (2019).
  • Enemies, Hand-in-hand: Pasteurella multocida in promoting biofilm and tumor cell proliferation (2018).
  • Effect of Clove oil on proteases of P. aeruginosa (2012).
  • Effect of essential oils on S. aureus biofilm and antimicrobial susceptibility (2010).

Under Graduate Dissertations Guided (BRITE Projects)

  • Antimicrobial and Anti-biofilm Activity of Essential Oils against A. baumannii- An in Vitro Study (2020)
  • Modulation of Host-Pathogen interaction to delineate the link between bacterial Infection and cancer progression (2020)
  • Anti-Quorum sensing, Anti-fungal activities of Meldrum’s acid and 1,3-  Dimethylbarbituric acid derivatives of furfural and Butyl Isothiocyanate. (2019)
  • Anti-biofilm, Anti-persister and Antibiotic Potentiation against A. baumannii: A Study with Plumbagin and Tobramycin. (2018)
  • Quorum Sensing inhibitors modulate persister cell formation of P. aeruginosa. (2017)
  • Interspecies interaction of P. aeruginosa in planktonic and biofilm co- cultures. (2016)
  • Clove essential oil Nano emulsion- Anti-biofilm and anti-virulence activity (2015)
  • Tetracycline augments anti-biofilm potential of essential oils and D- aminoacids. (2014)
  • Exploring the anti-pathogenic activity of Mangroves and Mangrove associated plants- an in vitro approach. (2012)
  • A study of biological activities of extracted microbial bio-surfactants. (2011)
  • Screening of dietary substances: New blockade strategy on quorum sensing. (2010)
  • Determination of anti-microbial activities of different spices against E. coli. (2009)
  • Anti-biofilm activity of plant extracts. (2008)