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An interactive environmental model for economic growth: evidence from a panel of countries

Ramakrishnan S, Hishan SS, Nabi AA, Arshad Z, Kanjanapathy M, Zaman K, et al.

Environ Sci Pollut Res Int, 2016 Jul;23(14):14567-79.
PMID: 27068914 DOI: 10.1007/s11356-016-6647-8

This study aims to determine an interactive environmental model for economic growth that would be supported by the "sustainability principles" across the globe. The study examines the relationship between environmental pollutants (i.e., carbon dioxide emission, sulfur dioxide emission, mono-nitrogen oxide, and nitrous oxide emission); population growth; energy use; trade openness; per capita food production; and it's resulting impact on the real per capita GDP and sectoral growth (i.e., share of agriculture, industry, and services in GDP) in a panel of 34 high-income OECD, high-income non-OECD, and Europe and Central Asian countries, for the period of 1995-2014. The results of the panel fixed effect regression show that per capita GDP are influenced by sulfur dioxide emission, population growth, and per capita food production variability, while energy and trade openness significantly increases per capita income of the region. The results of the panel Seemingly Unrelated Regression (SUR) show that carbon dioxide emission significantly decreases the share of agriculture and industry in GDP, while it further supports the share of services sector to GDP. Both the sulfur dioxide and mono-nitrogen oxide emission decreases the share of services in GDP; nitrous oxide decreases the share of industry in GDP; while mono-nitrogen oxide supports the industrial activities. The following key growth-specific results has been obtained from the panel SUR estimation, i.e., (i) Both the food production per capita and trade openness significantly associated with the increasing share of agriculture, (ii) food production and energy use significantly increases the service sectors' productivity; (iii) food production decreases the industrial activities; (iv) trade openness decreases the share of services to GDP while it supports the industrial share to GDP; and finally, (v) energy demand decreases along with the increase agricultural share in the region. The results emphasize the need for an interactive environmental model that facilitates the process of sustainable development across the globe.
Fulltext Bibliometric analysis of finance and natural resources: past trend, current development, and future prospects

Ali A, Ramakrishnan S, Faisal F, Akram T, Salam S, Rahman SU

Environ Dev Sustain, 2022 Aug 24.
PMID: 36039365 DOI: 10.1007/s10668-022-02602-1

The finance and natural resources revenue nexus play a critical role in an economy. The recent development and significant increase in academic literature regarding the resource-finance nexus are the primary motivations for conducting this study. This study aims to conduct a bibliometric analysis of 363 documents published between 1976 and 2021 collected from the Scopus database. The results have been demonstrated via graphs, tables, knowledge maps about the past trends, growth, and prospects using co-occurrence, co-authorship, and co-citation analysis via the VOSviewer tool. This study has identified prolific authors, journals, countries, academic institutions, and future pathways. The findings indicate that China has the highest share of publications (88, 24.2%), followed by Pakistan (58, 15.9%) and Turkey (37, 10.2%). The most productive academic institution is the Beijing Institute of Technology in China (13, 3.6%). This study proposes new avenues for further research concerning the resource-finance nexus, such as ecological footprint, sustainability, fiscal decentralization, green investment, energy prices, environmental quality, technological innovation, financial resource curse (especially the stock market resource curse), human capital, and renewable energy in policy development and sustainability towards the achievement of the SDGs.
Fulltext Selective phytochemicals targeting pancreatic stellate cells as new anti-fibrotic agents for chronic pancreatitis and pancreatic cancer

Ramakrishnan P, Loh WM, Gopinath SCB, Bonam SR, Fareez IM, Mac Guad R, et al.

Acta Pharm Sin B, 2020 Mar;10(3):399-413.
PMID: 32140388 DOI: 10.1016/j.apsb.2019.11.008

Activated pancreatic stellate cells (PSCs) have been widely accepted as a key precursor of excessive pancreatic fibrosis, which is a crucial hallmark of chronic pancreatitis (CP) and its formidable associated disease, pancreatic cancer (PC). Hence, anti-fibrotic therapy has been identified as a novel therapeutic strategy for treating CP and PC by targeting PSCs. Most of the anti-fibrotic agents have been limited to phase I/II clinical trials involving vitamin analogs, which are abundant in medicinal plants and have proved to be promising for clinical application. The use of phytomedicines, as new anti-fibrotic agents, has been applied to a variety of complementary and alternative approaches. The aim of this review was to present a focused update on the selective new potential anti-fibrotic agents, including curcumin, resveratrol, rhein, emodin, green tea catechin derivatives, metformin, eruberin A, and ellagic acid, in combating PSC in CP and PC models. It aimed to describe the mechanism(s) of the phytochemicals used, either alone or in combination, and the associated molecular targets. Most of them were tested in PC models with similar mechanism of actions, and curcumin was tested intensively. Future research may explore the issues of bioavailability, drug design, and nano-formulation, in order to achieve successful clinical outcomes with promising activity and tolerability.
Potent halogenated xanthone derivatives: synthesis, molecular docking and study on antityrosinase activity

Baharuddin FF, Mad Nasir N, Tejo BA, Koh SP, Ramakrishnan S, Nordin NQAA, et al.

J Asian Nat Prod Res, 2024 May;26(5):575-582.
PMID: 37796247 DOI: 10.1080/10286020.2023.2264784

Tyrosinase inhibitors can reduce melanin production for skin whitening, but some existing products may harm the skin. This study discovered six compounds that inhibit tyrosinase in the mushroom Agaricus bisporus by over 50%. Compound 11 displayed strong inhibition (92.2% and 86.7%) for L-tyrosine and L-DOPA substrates, while compound 13 showed high inhibition (96.0% and 62.0%) for both substrates. Molecular docking simulations revealed compounds 11 and 13 bind at the allosteric site of the enzyme. Xanthone derivatives, based on these findings, hold potential as safe skin whitening agents and for pigmentation-related diseases in the cosmetic industry.
Fulltext In-vivo anti-hyperglycemic effect of herbal extracts Tribulus terrestris (L) and Curcuma amada (R) on streptozotocin-induced diabetic rats and its associated histopathological studies

Kaliaperumal K, Bhat BA, Subramanian K, Ramakrishnan T, Chakravarthy E, Al-Keridis LA, et al.

Heliyon, 2024 Jan 15;10(1):e24009.
PMID: 38230238 DOI: 10.1016/j.heliyon.2024.e24009

Dia/betes is a serious health concern in many countries with high blood glucose, obesity, and multiple organ failures in late stages. Treating diabetes with effective drugs is still a challenging issue since most of the available diabetic drugs are not effective in combating diabetes, especially in secondary disease complications like obesity, retinopathy, and nephropathy associated with diabetes. Hence search for effective antidiabetic medication, especially from natural sources is mandatory with no adverse side effects. In the present study, a combined herbal aqueous extract of Tribulus terrestris and Curcuma amada was administered to diabetic-induced rats for 37 days. During experimentation, the mean blood glucose level was estimated and at the end of the experiment on the 37th day, the animal was sacrificed and observed for weight gain, plasma insulin, glycogen, glycated hemoglobin, urea, and creatinine level. The results revealed that TT and CA extract-treated diabetic groups significantly lowered the mean blood glucose level followed by increased glycogen and insulin level. Urea, creatinine, and HbA1c levels were considerably reduced in TT and CA-treated diabetic animals as compared to that of antidiabetic drug Glibenclamide-treated groups. TT and CA-treated diabetic animals showed considerable net body weight gain at the end of the experimental day. A concluding remark of the study shows that TT and CA herbal extract is effective against diabetes and it can be considered as an antidiabetic agent in ayurvedic medicine practice.
Polyaromatic hydrocarbons (PAHs) in the water environment: A review on toxicity, microbial biodegradation, systematic biological advancements, and environmental fate

Vijayanand M, Ramakrishnan A, Subramanian R, Issac PK, Nasr M, Khoo KS, et al.

Environ Res, 2023 Mar 20;227:115716.
PMID: 36940816 DOI: 10.1016/j.envres.2023.115716

Polycyclic aromatic hydrocarbons (PAHs) are considered a major class of organic contaminants or pollutants, which are poisonous, mutagenic, genotoxic, and/or carcinogenic. Due to their ubiquitous occurrence and recalcitrance, PAHs-related pollution possesses significant public health and environmental concerns. Increasing the understanding of PAHs' negative impacts on ecosystems and human health has encouraged more researchers to focus on eliminating these pollutants from the environment. Nutrients available in the aqueous phase, the amount and type of microbes in the culture, and the PAHs' nature and molecular characteristics are the common factors influencing the microbial breakdown of PAHs. In recent decades, microbial community analyses, biochemical pathways, enzyme systems, gene organization, and genetic regulation related to PAH degradation have been intensively researched. Although xenobiotic-degrading microbes have a lot of potential for restoring the damaged ecosystems in a cost-effective and efficient manner, their role and strength to eliminate the refractory PAH compounds using innovative technologies are still to be explored. Recent analytical biochemistry and genetically engineered technologies have aided in improving the effectiveness of PAHs' breakdown by microorganisms, creating and developing advanced bioremediation techniques. Optimizing the key characteristics like the adsorption, bioavailability, and mass transfer of PAH boosts the microorganisms' bioremediation performance, especially in the natural aquatic water bodies. This review's primary goal is to provide an understanding of recent information about how PAHs are degraded and/or transformed in the aquatic environment by halophilic archaea, bacteria, algae, and fungi. Furthermore, the removal mechanisms of PAH in the marine/aquatic environment are discussed in terms of the recent systemic advancements in microbial degradation methodologies. The review outputs would assist in facilitating the development of new insights into PAH bioremediation.
Electrospun nanofibers of collagen and chitosan for tissue engineering and drug delivery applications: A review

Ramakrishnan P, Ramprasath R, Jalaludeen AM, Jayakumar R, Jolius G, Balu R, et al.

Int J Biol Macromol, 2025 Mar;296:139663.
PMID: 39793786 DOI: 10.1016/j.ijbiomac.2025.139663

Tissue engineering plays a vital role in the medical field that addresses the repair, regeneration, and replacement of damaged tissues or organs. The development of drug-eluting electrospun nanofiber composed of biological macromolecules plays a key role in providing localized drug delivery and structural support. This review examines the recent development and impact of electrospun nanofibers in the field of tissue engineering and explores their potential applications. This review also investigates into the fabrication techniques of nanofibers, highlighting the use of biopolymers like collagen and chitosan, chiefly, focuses on understanding the mechanisms of drug-releasing features of these nanofibers. Studies concerning the medical applications of these nanofibers, such as wound healing, skin regeneration, bone tissue engineering, and neural repair, were also reviewed. Beyond the application in tissue regeneration, this review also explores the potential efficacy of nanofibres in cancer therapy, antibacterial activity, enzyme immobilization, and biosensing applications. This study provides an up-to-date critical insight into the applications of electrospun nanofiber application and key scalable production processes, underscoring the potential economic impacts of advanced wound care technologies. While outlining current challenges, this paper also offers future perspectives on the design, application, and potential expansion of drug-eluting electrospun fibers in medical sciences, ultimately showcasing their pivotal role in advancing therapeutic outcomes.
Thraatchathi Chooranam, protects cardiomyocytes against oxidative stress

Ganapathy R, Mani S, Hanumanth Rao BR, Tunku K, Ray B, Bhat A, et al.

Front Biosci (Elite Ed), 2018 03 01;10:437-448.
PMID: 29293467

Thraatchathi Chooranam (TC), is a polyphenol-rich Indian traditional medicine. Present study was undertaken to investigate the effects of TC against H2O2 induced oxidative stress and apoptotic damage in H9C2 cardiomyocytes. Cell viability assay indicated relative safety (IC50= 488.10±12.04 mg/ml) of TC. Pretreatment of cells with TC upregulated anti-apoptotic Bcl2, and anti-oxidants TRX1 and TRXR and downregulated Bax and HIF-α and inflammatory genes iNOS and TNF-α. Together, these findings show that TC has both anti-oxidant and anti-apoptotic properties. Further studies may be considered to identify the bioactive principle(s) and precise mechanisms of action of TC.
Fulltext Kinetic modeling of bacteriocin-like inhibitory substance secretion by Pediococcus acidilactici Kp10 and its stability in food manufacturing conditions

Abbasiliasi S, Tan JS, Ibrahim TAT, Ramanan RN, Kadkhodaei S, Mustafa S, et al.

J Food Sci Technol, 2018 Apr;55(4):1270-1284.
PMID: 29606741 DOI: 10.1007/s13197-018-3037-x

This paper deliberates the modelling and validation of bacteriocin-like inhibitory substance (BLIS) secretion by Pediococcus acidilactici Kp10 at different agitation speeds in a stirred tank bioreactor. A range of models namely the re-parameterised logistic, Luedeking-Piret and maintenance energy were assessed to predict the culture performance of the said bacterium. Growth of P. acidilactici Kp10 was enhanced with increased agitation speed up to 600 rpm while BLIS secretion was maximum at 400 rpm but decreased at higher agitation speed. Growth of P. acidilactici aptly subscribed to the re-parameterised logistic model while BLIS secretion and lactose consumption fitted well with the Luedeking-Piret model. The models revealed a relationship between growth of the bacterium and BLIS secretion. Bacterial growth and BLIS secretion were largely affected by the agitation speed of the stirred tank bioreactor which regulated the oxygen transfer to the culture. BLIS secretion by P. acidilactici Kp10 was however enhanced in oxygen-limited culture. The study also assessed BLIS from the perspective of its stability when subjected to factors such as temperature, pH and detergents. Results showed that BLIS produced by this strain was not affected by heat (at 25-100 °C for 20 min and at 121 °C for 15 min), surfactant (Tween 40, 60 and 80 and urea), detergents (up to 1% SDS), organic solvents (50% each of acetone, methanol and ethanol) and stable in a wide range of pH (2-10). The above information are pertinent with reference to commercial applications of this bacterial product in food manufacturing which invariably involve various sterilization processes and subjected to a wide pH range.
Heavy metal pollution in immobile and mobile components of lentic ecosystems-a review

Meena RAA, Sathishkumar P, Ameen F, Yusoff ARM, Gu FL

Environ Sci Pollut Res Int, 2018 Feb;25(5):4134-4148.
PMID: 29247419 DOI: 10.1007/s11356-017-0966-2

With growing population and urbanization, there is an increasing exploitation of natural resources, and this often results to environmental pollution. In this review, the levels of heavy metal in lentic compartments (water, sediment, fishes, and aquatic plants) over the past two decades (1997-2017) have been summarized to evaluate the current pollution status of this ecosystem. In all the compartments, the heavy metals dominated are zinc followed by iron. The major reason could be area mineralogy and lithogenic sources. Enormous quantity of metals like iron in estuarine sediment is a very natural incident due to the permanently reducing condition of organic substances. Contamination of cadmium, lead, and chromium was closely associated with anthropogenic origin. In addition, surrounding land use and atmospheric deposition could have been responsible for substantial pollution. The accumulation of heavy metals in fishes and aquatic plants is the result of time-dependent deposition in lentic ecosystems. Moreover, various potential risk assessment methods for heavy metals were discussed. This review concludes that natural phenomena dominate the accumulation of essential heavy metals in lentic ecosystems compared to anthropogenic sources. Amongst other recent reviews on heavy metals from other parts of the world, the present review is executed in such a way that it explains the presence of heavy metals not only in water environment, but also in the whole of the lentic system comprising sediment, fishes, and aquatic plants.
Fulltext Evaluation of serum and salivary alkaline phosphatase levels in chronic periodontitis patients before and after nonsurgical periodontal therapy

Jeyasree RM, Theyagarajan R, Sekhar V, Navakumar M, Mani E, Santhamurthy C

J Indian Soc Periodontol, 2019 1 12;22(6):487-491.
PMID: 30631226 DOI: 10.4103/jisp.jisp_133_18

Background: The traditional method of diagnosing periodontitis includes the assessment of clinical parameters and radiographic aids to evaluate the periodontal tissue destruction. Saliva has the potential to be used as the diagnostic fluid for oral disease. This study aimed at comparing the quantitative levels of alkaline phosphatase (ALP) in saliva and serum before and after scaling and root planing in patients with chronic generalized periodontitis.
Materials and Methods: A total number of 50 participants (40 with chronic generalized periodontitis and 10 periodontally healthy volunteers) of 30-50 years were included in the study. Clinical parameters such as simplified oral hygiene index (OHI-S), gingival index, probing depth, and clinical attachment loss (CAL) were measured, and then, saliva and blood sample collection was done and analyzed for ALP levels by spectrometry. The clinical parameters along with saliva and serum ALP levels were reevaluated after 30 days following Phase I periodontal therapy. The results were statistically analyzed using paired t-test and one-way ANOVA.
Results: The saliva and serum ALP levels were significantly increased in patients with chronic generalized periodontitis with an increase in clinical parameters such as OHI-S, gingival index, probing depth, and CAL when compared with periodontally healthy individuals. The saliva and serum ALP levels were significantly decreased following Phase I periodontal, therapy along with improvement in clinical parameters.
Conclusion: With the limitations of the present study, it could be concluded that ALP levels in saliva can be used for the diagnosis of active phase of periodontal disease and also for evaluation of the treatment outcomes following Phase I periodontal therapy.
A facile water-induced complexation of lycopene and pectin from pink guava byproduct: Extraction, characterization and kinetic studies

Nagarajan J, Krishnamurthy NP, Nagasundara Ramanan R, Raghunandan ME, Galanakis CM, Ooi CW

Food Chem, 2019 Oct 30;296:47-55.
PMID: 31202305 DOI: 10.1016/j.foodchem.2019.05.135

The redfleshed pulp discarded from pink guava puree industry is a rich source of lycopene and pectin. In this study, we developed a facile extraction process employing water as the primary extraction medium to isolate the lycopene and pectin from pink guava decanter. When the decanter was suspended in water, the complexation of lycopene and pectin formed the cloudy solution, where the colloidal complexes were recovered through centrifugation. The presence of lycopene and pectin in the complex was confirmed by the spectroscopic, microscopic and chromatographic analyses. The lycopene fractionated from the complexes had a purity level of 99% and was in all-trans configuration. The colloidal complexes yielding the highest concentration of lycopene was obtained at pH 7, 1% (w/v) solid loading and 25 °C. The experimental data of time-course extraction of lycopene-pectin complex were best fitted with two-site kinetic model, hinting the fast- and slow-release phases in the extraction process.
Stepwise optimization of recombinant protein production in Escherichia coli utilizing computational and experimental approaches

Packiam KAR, Ramanan RN, Ooi CW, Krishnaswamy L, Tey BT

Appl Microbiol Biotechnol, 2020 Apr;104(8):3253-3266.
PMID: 32076772 DOI: 10.1007/s00253-020-10454-w

Over the past few decades, Escherichia coli (E. coli) remains the most favorable host among the microbial cell factories for the production of soluble recombinant proteins. Recombinant protein production (RPP) via E. coli is optimized at the level of gene expression (expression level) and the process condition of fermentation (process level). Presently, the reported studies do not give a clear view on the selection of methods employed in the optimization of RPP. Here, we have reviewed various optimization methods and their preferences with respect to the factors at expression and process levels to achieve the optimal levels of soluble RPP. With a greater understanding of these optimization methods, we proposed a stepwise methodology linking the factors from both levels for optimizing the production of soluble recombinant protein in E. coli. The proposed methodology is further explained through five sets of examples demonstrating the optimization of RPP at both expression and process levels.Key Points• Stepwise methodology of optimizing recombinant protein production is proposed.• In silico tools can facilitate the optimization of gene- and protein-based factors.• Optimization of gene- and protein-based factors aids host-vector selection.• Statistical optimization is preferred for achieving optimal levels of process factors.
Isolation, characterization and the potential use of starch from jackfruit seed wastes as a coagulant aid for treatment of turbid water

Choy SY, Prasad KM, Wu TY, Raghunandan ME, Yang B, Phang SM, et al.

Environ Sci Pollut Res Int, 2017 Jan;24(3):2876-2889.
PMID: 27838910 DOI: 10.1007/s11356-016-8024-z

Fruit wastes constituting up to half of total fruit weight represent a large pool of untapped resources for isolation of starch with diverse applications. In this work, the possibility of isolating starch from tropical fruit wastes and its extended application as a natural coagulant was elucidated. Amongst the 12 various parts of fruit wastes selected, only jackfruit seeds contained more than 50% of total starch content. Using alkaline extraction procedures, starch has been successfully isolated from local jackfruit seeds with a yield of approximately 18%. Bell-shaped starch granules were observed under SEM with a granule size ranging from 1.1 to 41.6 μm. Detailed starch characteristics were performed to provide a comparison between the isolated seed starch and also conventional starches. Among them, chemical properties such as the content of starch, amylose, amylopectin and the corresponding molecular weights are some of the key characteristics which governed their performance as natural coagulants. The potential use of isolated seed starch as an aid was then demonstrated in both suspensions of kaolin (model synthetic system) and Chlorella sp. microalga (real-time application) with plausible outcomes. At optimized starch dosage of 60 mg/L, the overall turbidity removal in kaolin was enhanced by at least 25% at a fixed alum dosage of 2.1 mg/L. Positive turbidity and COD removals were also observed in the treatment of Chlorella suspensions. Starches which served as bridging agents aided in the linkage of neighbouring microflocs and subsequently, forming macroflocs through a secondary coagulation mechanism: adsorption and bridging.
Blastocystis in animal handlers

Rajah Salim H, Suresh Kumar G, Vellayan S, Mak JW, Khairul Anuar A, Init I, et al.

Parasitol Res, 1999 Dec;85(12):1032-3.
PMID: 10599928

The present study investigated whether people working closely with animals were at higher risk of getting infected with Blastocystis hominis. The prevalence of the parasite was determined in two population groups, i.e., animal handlers and normal healthy individuals who did not work with animals. In all, 105 stool samples were collected from animal handlers from 2 local research institutions, a local zoo, and a local abattoir and 163 stool samples were collected from normal healthy individuals residing in high-rise flats in the city. The in vitro culture method used in the study detected that 41% of 105 animal handlers and 17% of 163 flat-dwellers in the city were positive for Blastocystis. This statistically significant finding (P = 0.0000313) shows that people who work closely with animals do stand at risk of acquiring Blastocystis infection.
Long-term nasogastric tube feeding in elderly stroke patients--an assessment of nutritional adequacy and attitudes to gastrostomy feeding in Asians

Zaherah Mohamed Shah F, Suraiya HS, Poi PJ, Tan KS, Lai PS, Ramakrishnan K, et al.

J Nutr Health Aging, 2012 Aug;16(8):701-6.
PMID: 23076512 DOI: 10.1007/s12603-012-0027-y

BACKGROUND: Gastrostomy feeding is superior to long-term nasogastric (NG) feeding in patients with dysphagic stroke, but this practice remains uncommon in Asia. We sought to examine the nutritional adequacy of patients on long term NG feeding and identify barriers to gastrostomy feeding in these patients.
METHODOLOGY: A prospective comparison of subjective global assessment (SGA), and anthropometry (mid-arm muscle circumference, MAMC; triceps skinfold thickness, TST) between elderly stroke patients on long-term NG feeding and matched controls was performed. Selected clinicians and carers of patients were interviewed to assess their knowledge and attitudes to gastrostomy feeding.
RESULTS: 140 patients (70 NG, 70 oral) were recruited between September 2010 and February 2011. Nutritional status was poorer in the NG compared to the oral group (SGA grade C 38.6% NG vs 0% oral, p<0.001; TST males 10.7 + 3.7 mm NG vs 15.4 + 4.6 mm oral, p<0.001; MAMCmales 187.9 + 40.4 mm NG vs 228.7 + 31.8 mm oral, p<0.001). 45 (64.3%) patients on long-term NG feeding reported complications, mainly consisting of dislodgement (50.5%), aspiration of feed content (8.6%) and trauma from insertion (4.3%). Among 20 clinicians from relevant speciliaties who were interviewed, only 11 (55%) clinicians would routinely recommend a PEG. All neurologists (100%) would recommend a PEG, whilst the response was mixed among non-neurologists. Among carers, lack of information (47.1%) was the commonest reason stated for not choosing a PEG.
CONCLUSION: Elderly patients with stroke on long term NG feeding have a poor nutritional status. Lack of recommendation by clinicians appears to be a major barrier to PEG feeding in these patients.
Comparison of the estimation capabilities of response surface methodology and artificial neural network for the optimization of recombinant lipase production by E. coli BL21

Nelofer R, Ramanan RN, Rahman RN, Basri M, Ariff AB

J Ind Microbiol Biotechnol, 2012 Feb;39(2):243-54.
PMID: 21833714 DOI: 10.1007/s10295-011-1019-3

Response surface methodology (RSM) and artificial neural network (ANN) were used to optimize the effect of four independent variables, viz. glucose, sodium chloride (NaCl), temperature and induction time, on lipase production by a recombinant Escherichia coli BL21. The optimization and prediction capabilities of RSM and ANN were then compared. RSM predicted the dependent variable with a good coefficient of correlation determination (R² and adjusted R² values for the model. Although the R (2) value showed a good fit, absolute average deviation (AAD) and root mean square error (RMSE) values did not support the accuracy of the model and this was due to the inferiority in predicting the values towards the edges of the design points. On the other hand, ANN-predicted values were closer to the observed values with better R², adjusted R², AAD and RMSE values and this was due to the capability of predicting the values throughout the selected range of the design points. Similar to RSM, ANN could also be used to rank the effect of variables. However, ANN could not predict the interactive effect between the variables as performed by RSM. The optimum levels for glucose, NaCl, temperature and induction time predicted by RSM are 32 g/L, 5 g/L, 32°C and 2.12 h, and those by ANN are 25 g/L, 3 g/L, 30°C and 2 h, respectively. The ANN-predicted optimal levels gave higher lipase activity (55.8 IU/mL) as compared to RSM-predicted levels (50.2 IU/mL) and the predicted lipase activity was also closer to the observed data at these levels, suggesting that ANN is a better optimization method than RSM for lipase production by the recombinant strain.
Fulltext Probing the molecular interactions between cholinium-based ionic liquids and insulin aspart: A combined computational and experimental study

Sundaram V, Ramanan RN, Selvaraj M, Ahemad N, Vijayaraghavan R, MacFarlane DR, et al.

Int J Biol Macromol, 2023 Dec 31;253(Pt 3):126665.
PMID: 37689282 DOI: 10.1016/j.ijbiomac.2023.126665

Despite extensive studies revealing the potential of cholinium-based ionic liquids (ILs) in protein stabilization, the nature of interaction between ILs' constituents and protein residues is not well understood. In this work, we used a combined computational and experimental approach to investigate the structural stability of a peptide hormone, insulin aspart (IA), in ILs containing a choline cation [Ch]+ and either dihydrogen phosphate ([Dhp]-) or acetate ([Ace]-) as anions. Although IA remained stable in both 1 M [Ch][Dhp] and 1 M [Ch][Ace], [Dhp]- exhibited a much stronger stabilization effect than [Ace]-. Both the hydrophilic ILs intensely hydrated IA and increased the number of water molecules in IA's solvation shell. Undeterred by the increased number of water molecules, the native state of IA's hydrophobic core was maintained in the presence of ILs. Importantly, our results reveal the importance of IL concentration in the medium which was critical to maintain a steady population of ions in the microenvironment of IA and to counteract the denaturing effect of water molecules. Through molecular docking, we confirm that the anions exert the dominant effect on the structure of IA, while [Ch]+ have the secondary influence. The computational results were validated using spectroscopic analyses (ultra-violet, fluorescence, and circular dichroism) along with dynamic light scattering measurements. The extended stability of IA at 30 °C for 28 days in 1 M [Ch][Dhp] and [Ch][Ace] demonstrated in this study reveals the possibility of stabilizing IA using cholinium-based ILs.
Enhanced activity of Candida antarctica lipase B in cholinium aminoate ionic liquids: a combined experimental and computational analysis

Chan KK, Sundaram V, Tan J, Ho YK, Ramanan RN, Ooi CW

J Biomol Struct Dyn, 2024;42(21):11351-11365.
PMID: 37787564 DOI: 10.1080/07391102.2023.2262590

As a class of ionic liquids with higher biocompatibility, cholinium aminoates ([Cho][AA]) hold potential as solvation media for enzymatic bioprocessing. Herein, solvation effect of [Cho][AA] on structural stability and enzymatic activity of Candida antarctica lipase B (CALB) was evaluated using experimental and computational approaches. Influence of [Cho][AA] on CALB stability was investigated using amino acid anions ([AA]-) with varying hydrophobicity levels. Choline phenylalaninate ([Cho][Phe]) resulted in 109.1% and 110.4% of relative CALB activity to buffer medium at 25 °C and 50 °C, respectively. Simulation results revealed the improvement of CALB's enzymatic activities by [AA]- with a strong hydrophobic character. Shielding of CALB from water molecules by [AA]- was observed. The level of CALB activity was governed by accumulation level of [AA]- at CALB's first hydration layer. The stronger interaction between His224 and Asp187 was postulated to be driven by [Cho][AA], resulting in the activity enhancement of CALB. The slight improvement of CALB activity in 0.05 M [Cho][Phe] at 50 °C could be due to the larger size of entrance to the catalytic site and the stronger interaction between the catalytic residues. The promising effect of [Cho][Phe] on CALB activation may stimulate research efforts in designing a 'fully green' bioreaction for various industrial applications.Communicated by Ramaswamy H. Sarma.
Utilization of plant-based natural coagulants as future alternatives towards sustainable water clarification

Choy SY, Prasad KM, Wu TY, Raghunandan ME, Ramanan RN

J Environ Sci (China), 2014 Nov 1;26(11):2178-89.
PMID: 25458671 DOI: 10.1016/j.jes.2014.09.024

Rapid industrial developments coupled with surging population growth have complicated issues dealing with water scarcity as the quest for clean and sanitized water intensifies globally. Existing fresh water supplies could be contaminated with organic, inorganic and biological matters that have potential harm to the society. Turbidity in general is a measure of water cloudiness induced by such colloidal and suspended matters and is also one of the major criteria in raw water monitoring to meet the stipulated water quality guidelines. Turbidity reduction is often accomplished using chemical coagulants such as alum. The use of alum is widely associated with potential development of health issues and generation of voluminous sludge. Natural coagulants that are available in abundance can certainly be considered in addressing the drawbacks associated with the use of chemical coagulants. Twenty one types of plant-based natural coagulants categorized as fruit waste and others are identified and presented collectively with their research summary in this review. The barriers and prospects of commercialization of natural coagulants in near future are also discussed.

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