Institutional Repository

Scholar@UOC is the primary academic repository of the University of Calicut.

This repository is aimed to collect, preserve and distribute the research output of the members of our University. This is an open access system hosted and managed by the University Library.

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Recent Submissions

The role of palmitic acid on endoplasmic reticulum stress: implication In cancer cell survival
(Amala Cancer Research Center, Trissur, 2025) Soumya V V; Babu T D; Binoy C F
Palmitic acid, a major saturated fatty acid found in palm oil and other dietary sources, plays a crucial role in cellular metabolism, particularly in lipid metabolism, oxidative stress, and endoplasmic reticulum (ER) stress. When excessive palmitic acid induces ER stress, where protein-folding demands surpass the capacity of ER, it may disrupt cellular balance and potentially lead to cell dysfunction or death. Considering the evidence linking ER stress to various pathological conditions, understanding the mechanistic impact of palmitic acid on ER stress and cellular fate is crucial. This study investigates the molecular pathways through which palmitic acid influences ER stress and its downstream effects, providing insights into its potential role in disease progression and metabolic disorders. Additionally, UPR signalling in metastasised tumour-bearing mice administered with palm oil will be analysed. In vitro experiments revealed a decline in cell viability dose-dependently across all cell lines. Notably, IEC6 cells exhibited greater tolerance (IC50: 342 μM) than cancer cells, with IC50 values of 180 μM for HCT116 and 168 μM for CT26. Morphological alterations, including cell structure disruption, were minimal at lower concentrations but became significant at higher doses. Both normal and cancer cells were found to accumulate neutral lipids, indicating the involvement of fatty acid transport proteins. Notably, both normal cells and cancer cells showed significant lipid accumulation even at lower concentrations and retained the ability to form colonies, indicating resilience under metabolic stress. However, at higher concentrations, palmitic acid disrupted lipid metabolism and compromised antioxidant defences, ultimately leading to cell death. Excess lipid accumulation in cells led to increased ROS and the accumulation of misfolded proteins at both low and high doses. The upregulation of ER stress marker genes Bip, Chop, and Atf6 further indicated ER stress and misfolded protein accumulation. These findings suggest that palmitic acid disrupts protein folding mechanisms and ER functionality at higher concentrations, leading to cellular dysfunction, while cells can withstand the stress at lower concentrations, indicating that oxidative stress-associated metabolic stresses play a crucial role in ER stress in pathological and physiological contexts. The ER stress-associated UPR pathways, particularly PERK/ATF4, IRE1/XBP1, and ATF6, play a crucial role in cell survival under stress. Palmitic acid is found to activate the PERK pathway and enhance the antioxidant enzymes like superoxide dismutase ix(SOD), catalase (CAT) etc, at sub-lethal doses. However, the activity declined to its toxic level. The glutathione-based antioxidants were stable at lower doses but dropped significantly at toxic concentrations, emphasising their role in detoxifying palmitic acid metabolites. Lipid peroxidation level was also increased by palmitic acid, diminishing antioxidant defences, compromising membrane integrity, and heightening oxidative stress at higher doses. Stress-responsive factors Nrf2, Nqo1and Ho-1, key antioxidant defence and autophagy regulators, showed variable expression. The cancer cells, HCT116 and CT26, displayed Nrf2 upregulation compared to normal IEC6 cells. This highlights the adaptive responses of cancer cells under toxic stress to maintain homeostasis. This may lead to cell survival mechanisms. Palmitic acid treatment resulted in the formation of acidic vacuoles, indicating an autophagic response. Further, acidic vacuoles led to autophagy, as evidenced by MDC staining. The expression of autophagy-related genes Beclin 1 and Lc3b1, along with UPR markers Ire1 and Xbp1, was upregulated particularly in cancer cells, suggesting that palmitic acid enhances cellular resistance to stress through the activation of both autophagy and ER stress pathways. This link between autophagy and ER stress is critical, as autophagy alleviates ER stress by degrading damaged cellular components, while the UPR regulates autophagic flux. This interaction may promote cell survival and progression in colon cancer, indicating potential therapeutic strategies for targeting these pathways to inhibit cancer survival mechanisms. In vivo studies were conducted using a palm oil-rich diet to analyse the impact of prolonged intake of heat-treated palm oil (HPO), which is high in palmitic acid, on colon cancer metastasis. Using gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) analysis determined a palmitic acid concentration of 367 mg/mL in HPO. Over four months, mice received 200 μl of HPO, corresponding to 73.4 mg of palmitic acid per mouse. HPO consumption caused oxidative stress and reduced antioxidant levels in the small intestine, leading to increased lipid peroxidation. This oxidative stress was less pronounced in the large intestine due to its limited lipid absorption capacity. Histopathological analysis revealed significant alterations in goblet cell morphology, inflammation, and ER stress development in the intestinal tissues. Prolonged HPO intake led to the upregulation of ER stress markers such as BIP, CHOP, and ATF6 and the activation of different UPR pathways, with the PERK/ATF4 xpathway being more active in the small intestine and the IRE1/XBP1 pathway in the large intestine. The study investigated the effect of HPO on CT26 cell-induced colon cancer pulmonary metastasis. Oral administration of HPO in mice with CT26 inoculated cancer led to metastasis along with inflammatory cell infiltration. Consistent with previous findings, HPO promoted metastasis through the TLR4/TRIF-Peli1-pNF-κB pathway, while CD36 blockade effectively inhibited this process. HPO treatment exhibited significant body weight loss, glucose intolerance, and systemic inflammation, accompanied by elevated counts of white blood cells, monocytes, neutrophils, lymphocytes, and platelets, suggesting immune modulation. Additionally, HPO influenced lipid metabolism in cancer progression, as evidenced by increased serum cholesterol, triglycerides, and LDL levels. Elevated AST and ALT levels indicated liver dysfunction, while increased lung hydroxyproline and collagen deposition suggested a potential link between HPO exposure and pulmonary fibrosis. The colon cancer pulmonary metastasis further impacted inflammatory responses, oxidative stress, ER stress, and associated signalling pathways by HPO. Palmitic acid- induced inflammation in lung tissues, characterised by elevated levels of IL-6 and TNF- α, creates a microenvironment favourable for metastatic spread. Increased immune cell infiltration and invasion further supported the role of HPO-induced inflammation in facilitating cancer cell aggressiveness. Chronic HPO intake disrupted redox homeostasis in lung tissues, leading to oxidative damage exacerbated by alterations in antioxidant enzymes. Significant changes in glutathione-related enzymes without corresponding adjustments in SOD and CAT underscored a dysregulated antioxidant defence system, potentiating oxidative stress and inflammation. HPO-induced ER stress, evidenced by the upregulation of ER stress markers like Bip, Chop, Atf6, and the activation of Perk/Atf4 and Ire1/Xbp1 signalling pathways, contributed to a pro- tumorigenic microenvironment favouring cancer metastasis. In conclusion, palmitic acid-induced oxidative and ER stresses disrupt cellular homeostasis, triggering UPR pathways and impairing antioxidant defences. Cancer cells exhibit metabolic resistance, with increased lipid accumulation and stress adaptation mechanisms. In vivo, prolonged HPO intake led to systemic inflammation, immune modulation, and liver dysfunction. HPO-driven ER stress and inflammation in lung tissues, characterised by IL-6 and TNF-α elevation, created a tumour-promoting ximicroenvironment, facilitating metastatic progression. The dysregulation of antioxidant defence systems further exacerbated oxidative damage. CD36 blockade mitigated HPO-induced metastasis, underscoring the potential of targeting fatty acid metabolism in cancer therapy. These findings provide mechanistic insights into the interplay between lipid metabolism, ER stress, and tumour progression, emphasising the need for dietary interventions and therapeutic strategies to counteract palmitic acid-driven cancer aggressiveness.
Studies on nonlinear beam dynamics in uniaxial nematic liquid crystals under the influence of temperature, diffractive radiation, and potentials
(Research and Post Graduate Department of Physics, Govt.College Madappally, Vadakara-673102, 2025) Sajitha N M; Suneera T P
This thesis investigated the nonlinear beam dynamics in uniaxial nematic liquid crystals under the influence of temperature, diffractive radiation, and potentials.The study emphasizes the role of diffractive radiation in ensuring unclisturbed nematicon propagation by utilizing both variational and numerical rnethods. A key aspect of the research is the competition between focusing reorientational and defocusing thermal nonlinearities, which results in the formation of multi-peak nematicous. [t also iuvestigates how parabolic potential influences the generation of higher harmonics of nematicons. The stability of steady-state solutions against small perturbations is studied by applying the Bogoliubov-De-Gennes equations- The study has been extended to the thermal response of nematicons in a parabolic potential. Single-peak nematicons exist ouly in the absence of thermal response coefficients. The presence of both focusing reorientational and defocusing thermal nonlinearities creates multiple maxima in the energy landscape, allowing for the stabilization of doublepeak nematicous as equilibrium states. Periodic oscillations are observed in nematicons within a parabolic potential, with their wavelength being influenced by thermal response coefficients. The linear stability analysis reveals that single-peak and periodically oscillating double-peak nematicons are stable, whereas non-oscillating double'peak nematicons are unstable. The research also extends to study the formation and stability of gap nematicons. Finally, the study explores the effects of thermal response and difiractive radiation on multi-peak gap nematicons.
Study of soil fungi from selected sacred groves of Kerala
(Department of Botany, St. Thomas College (Autonomous), Thrissur, 2025) Keerthana Nandakumar; Ignatius Antony; Anto P. V
Sacred groves are believed to be dense patches of the once-vast evergreen forests of southwestern India, particularly in Kerala. Soil fungi have an important role in sustaining these sacred roves' rich and diverse vegetation. However, until recently, little was known about the fungi associated with these areas. Therefore, this study investigates the diversity, composition, and abundance of soil fungi of three sacred groves located in different parts of Kerala: Iringole Kavu, Kollakal Thapovanam, and Poyilkavu. Soil samples were collected from these groves across three seasons over two years using a composite soil sampling method. The serial dilution technique and metagenomics analysis were employed to isolate and identify the soil fungi. Using the serial dilution method, a total of 34 genera and 168 species of fungi were identified across six classes, with Ascomycota being the most dominant phylum, followed by Mucoromycota. Four unidentified species and two non-sporulating fungi were also collected. Sixteen new reports for India and eighteen new reports for Kerala were documented as part of the work. The class-wise distribution of fungi revealed that Eurotiomycetes was the most dominant class, while the genus Penicillium, followed by Aspergillus, became the predominant genus. Spatial and seasonal distribution of the taxa was analysed. Iringole Kavu exhibited the highest species richness (105 species), followed by Poyilkavu (67) and Kollakal Thapovanam (64). Seasonally, high species diversity was observed in Iringole Kavu during Pre 2, and in Mo 2 of both Kollakal Thapovanam and Poyilkavu. Fungal genera exclusive to each site and abundant species were listed. Spatial and seasonal variations in the number of fungi were documented. In the spatial and seasonal diversity analysis, Iringole Kavu exhibits a high level of diversity and maintains a balanced ecosystem. Species diversity also changes with the seasons. Hierarchical Cluster Analysis and Non-metric Multidimensional Scaling revealed that each sacred grove was distinct and possessed unique fungal flora. In total, 12 physicochemical parameters were studied, and statistical measures were calculated. The variation in these parameters across seasons was tested for significance, revealing strong influences on species diversity and distribution. Canonical Correspondence Analysis interpreted the correlations between physicochemical parameters and fungi. Indicator Species Analysis identified genera that serve as indicators for each season and site. Metagenomics analysis revealed five phyla, subdivided into 20 classes, 40 orders, 83 families, 119 genera, and 135 species. Eurotiomycetes predominated at the class level, while the genus Talaromyces dominated among the genera. Diversity analysis indicated that Kollakal Thapovanam was rich in fungal species. These findings highlight the unique and diverse ecosystems present in sacred groves, underscoring the need for conservation efforts to maintain their purity. This study is significant as it represents the first comprehensive analysis of soil fungi in the sacred groves of Kerala.
Tuning the magnetocaloric properties of nanomagnetic materials for magnetic refrigerant applications
(Vimala College, Thrissur, 2025) Smitha Bhaskaran; Veena Gopalan E
Magnetic refrigeration based on the magnetocaloric effect is becoming an emerging technology to replace conventional gas compression refrigeration as it is environmentally friendly, compact and highly efficient. Materials with magnetocaloric properties close to room temperature will be preferred for residential and commercial use as magnetic refrigerants. This research explores synthesis, characterisation and magnetocaloric properties of perovskite manganites, ferrites and nanocomposites. The structural, compositional, magnetic and magnetocaloric properties of the lanthanum sodium manganite (La0.5Na0.5MnO3) and cobalt substituted lanthanum sodium manganite (La0.5Na0.5CoxMn1-xO3) in the perovskite system, cobalt substituted copper ferrite (CuxCo1-xFe2O4) and zinc substituted copper ferrite (CuxZn1-xFe2O4) in the ferrite system and cobalt polystyrene nanocomposites samples are investigated by employing X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier-transform Infrared spectroscopy (FTIR), Energy-Dispersive X-ray spectroscopy (EDAX), and Vibrating Sample Magnetometry (VSM). The magnetocaloric properties of the samples are analysed around the transition temperature which is determined by Zero Field Cooled and Field Cooled (ZFC-FC) measurements. The magnetic entropy change is estimated from the magnetisation isotherms taken around the transition temperature and hence identified a potential magnetic refrigerant material near room temperature and lower temperatures.
The good the bad and the ugly the shifting paradigms of the christian hero stereotyping in malayalam cinema 1990 to 2017
(St.Joseph's College , Devagiri, 2025) Robin Xavier; Nagesh S
Cinema, as a discourse and a praxis of representation produces, reproduces and circulates images and symbols about the self and the other, men and women, and individuals and communities. This thesis examines the representation of Christian community power and Christian masculinities in Malayalam cinema from 1990 to 2017, focusing on the construction, reinforcement, and contestation of hegemonic masculine ideals. Malayalam cinema has historically elevated Syrian Christian masculinity through archetypes such as the hegemonic ―Achayans,‖ dominant bureaucrats, and overriding planter-cum-settlers. Drawing from film theory, cultural studies and masculinity studies, and using frameworks from Foucault, Bourdieu, Althusser, and Connell, the research explores how cinematic narratives construct selfhood and community identity with regard to class, caste, and gender. A historical survey of Malayalam cinema is carried out to reveal the evolution and self-fashioning of the Christian male as an ideologically dominant subjectivity. Critiquing the marginalisation of subaltern Christian groups in Malayalam cinema, the research traces how socio-political factors such as caste and class contribute to the formation of a hegemonic identity of Syrian Christians in the Kerala public sphere. The mainstream popular cinema becomes a tool in reinforcing hegemonies of class, caste and gender through the stereotypes of an all controlling patriarch, and thereby constructs community power. Challenging this, the depiction of subordinate masculinities such as those of Latin and Dalit Christians demonstrates the various subcultures marginalized in the process in a different genre and form. The research argues that even positive stereotypes function to homogenise community identities into a Syrian Christian one and cancel out the existence of diverse marginal communities in the 20th century. Malayalam cinema in the 21st century, nevertheless, demonstrates a contested cultural space where hegemonic Christian masculinities are both reinforced and critically deconstructed.