Biology subjects

Sadanandan, B.

Publications and source records attributed to Sadanandan, B..

3 recordsLinked to original sources

bioRxiv2026

Development of a UVGI System and Evaluation of Germicidal Potential Against Biofilm-Forming Bacteria and Fungi Under Controlled Laboratory Conditions

A compact, in-house developed ultraviolet germicidal irradiation (UVGI) system adaptable to static, mobile, or robotic platforms was developed for the effective sterilization of bacteria and fungi using a wireless mode of operation. Under controlled laboratory conditions, its efficacy was evaluated against three representative biofilm-forming pathogens: Bacillus subtilis (Gram-positive, spore-forming, motile bacterium), Escherichia coli K12 (Gram-negative, non-spore-forming, non-motile bacterium), and Candida albicans M-207 (multi-drug-resistant, clinical yeast isolate). Microbial viability following UVGI exposure was assessed using colony-forming unit (CFU) and MTT assays, and morphological alterations were characterized by scanning electron microscopy (SEM). Cultures were exposed to UV-C radiation at distances of 1-5 m for 15-90 min. CFU assay demonstrated 100% kill of all tested organisms at 1 m and 15 min, corresponding to doses of 600.3, 576 & 697.5 mJ/cm{superscript 2}. Although MTT assays indicated residual metabolic activity under the same conditions, CFU results confirmed that surviving cells were unable to proliferate, highlighting the robustness of UV treatment for long-term inactivation. SEM confirmed distinct morphological alterations such as complete destruction of extracellular matrix & reduction in number of cells indicating cell death with increase in UV dose as compared to controls. A dose & time-dependent inactivation of biofilm-forming bacteria & fungi was observed on exposure to UVGI. Therefore, this pilot study validates the effectiveness of the newly developed UVGI surface sterilizer against biofilm-forming bacterial and fungal pathogens. Overall, the system demonstrates proof-of-concept efficacy under laboratory conditions and holds strong potential for future development and validation in hospitals and other contaminated public spaces. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/715580v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@150cefcorg.highwire.dtl.DTLVardef@450831org.highwire.dtl.DTLVardef@1cfd6borg.highwire.dtl.DTLVardef@1419ba8_HPS_FORMAT_FIGEXP M_FIG C_FIG IMPORTANCEMicroorganisms that form biofilms on surfaces are difficult to eliminate and contribute to the spread of infections in healthcare and indoor environments. There is a need for practical, easy-to-use disinfection technologies that can effectively reduce such contamination. In this study, we developed a compact, in-house, wireless UV-C disinfection system designed for flexible operation across different surface types. The system was evaluated under controlled laboratory conditions using representative biofilm-forming bacterial and fungal pathogens. Our findings show that the system can effectively reduce microbial contamination, demonstrating proof-of-concept efficacy. This work highlights the potential of accessible, non-chemical UV-based technologies and supports their further validation for applications in real-world disinfection settings.

microbiology↗

bioRxiv2024

Comparative Analysis of DNA Structural Parameters and the Corresponding Computational Tools to Differentiate Regulatory DNA Motifs and Promoters

Analyzing and distinguishing functionally distinct DNA regions is crucial for various applications, including predicting DNA motifs and promoters, and exploring the mechanisms of gene expression regulation in disease conditions. Our understanding of mammalian promoters, particularly those associated with differentially expressed genes (DEGs), particularly remains limited. However, existing methods for such analysis require refinement. Despite the value of DNA Structural Parameters (DSPs), users often struggle to objectively select parameters and tools, especially given the limited options available. This study addresses this challenge by thoroughly investigating DSP-tool combinations - particularly the local structural parameters that can be analyzed via web-interfaces, with a goal to discern human DNA motifs and promoters. What sets this study apart are the following aspects: a) examination of disease-associated promoters; b) attention to regulatory specific DNA motifs; c) compilation and comparison of all publicly available online tools and parameters for analyzing DNA structures, and test all available DSP-tool combinations. Through the execution of over half a million queries, the study identified DSP-tool combinations that consistently outperformed others in differentiating DNA sequences across various types of analyses. Notably, the propeller twist emerged as a standout DSP, while DNAshape, complemented by DNAshapeR scripts, demonstrated exceptional performance among the tools across four distinct types of analyses: testing motifs, sequences post motif insertion, comparing promoters with control sequences, and analyzing promoters of genes either up- or down-regulated under disease conditions. Significant alterations were observed in the values of multiple DSPs for 100-nucleotide-long promoter and control sequences following the insertion of single motifs such as triplex target sites (TTS), quadruplex-forming structural motifs (QSFM), and transcription factor binding sites (TFBS). However, no single combination proved universally successful. For instance, when analyzing promoters associated with differential gene expression, different combinations proved effective across various human diseases. These findings provide valuable insights for making informed selections among available options for sequence-based queries.

bioinformatics↗

bioRxiv2023

Aqueous Spice Extracts as Alternative Antimycotics to Control Highly Drug Resistant Extensive Biofilm Forming Clinical Isolates of Candida albicans

Candida albicans forms biofilm by associating with biotic and abiotic surfaces. Biofilm formation by C. albicans is relevant and significant as the organisms residing within, gain resistance to conventional antimycotics and are therefore difficult to treat. This study targeted the potential of spice-based antimycotics to control C. albicans biofilms. Ten clinical isolates of C. albicans along with a standard culture MTCC-3017 (ATCC-90028) were screened for their biofilm-forming ability. C. albicans M-207 and C. albicans S-470 were identified as high biofilm formers by point inoculation on TSA medium as they formed a lawn within 16 h and exhibited resistance to fluconazole and caspofungin at 25 mcg and 8 mcg respectively. Aqueous and organic spice extracts were screened for their antimycotic activity against C. albicans M-207 and S-470 by agar and disc diffusion and Zone of Inhibition was observed. Minimal Inhibitory Concentration was determined based on growth absorbance and cell viability measurements. The whole aqueous extract of garlic inhibited biofilms of C. albicans M-207, whereas whole aqueous extracts of garlic, clove, and Indian gooseberry were effective in controlling C. albicans S-470 biofilm within 12 h of incubation. The presence of allicin, ellagic acid, and gallic acid as dominant compounds in the aqueous extracts of garlic, clove, and Indian gooseberry respectively was determined by High-Performance Thin Layer Chromatography and Liquid Chromatography-Mass Spectrometry. The morphology of C. albicans biofilm at different growth periods was also determined through bright field microscopy, phase contrast microscopy, and fluorescence microscopy. The results of this study indicated that the alternate approach in controlling high biofilm-forming, multi-drug resistant clinical isolates of C. albicans M-207 and S-470 using whole aqueous extracts of garlic, clove, and Indian gooseberry is a safe, potential, and cost-effective one that can benefit the health care needs with additional effective therapeutics to treat biofilm infections.

microbiology↗