Exploring the influence of microgravity on chemotherapeutic drug response in cancer: Unveiling new perspectives.

Microgravity, an altered gravity condition prevailing in space, has been reported to have a profound impact on human health. Researchers are very keen to comprehensively investigate the impact of microgravity and its intricate involvement in inducing physiological changes. Evidenced transformations were observed in the internal architecture including cytoskeletal organization and cell membrane morphology. These alterations can significantly influence cellular function, signalling pathways and overall cellular behaviour. Further, microgravity has been reported to alter in the expression profile of genes and metabolic pathways related to cellular processes, signalling cascades and structural proteins in cancer cells contributing to the overall changes in the cellular architecture. To investigate the effect of microgravity on cellular and molecular levels numerous ground-based simulation systems employing both in vitro and in vivo models are used. Recently, researchers have explored the possibility of leveraging microgravity to potentially modulate cancer cells against chemotherapy. These findings hold promise for both understanding fundamental processes and could potentially lead to the development of more effective, personalized and innovative approaches in therapeutic advancements against cancer.

Photodynamic therapy to control microbial biofilms.

Microorganisms thrive in well-organized biofilm ecosystems. Biofilm-associated cells typically show increased resistance to antibiotics and contribute significantly to treatment failure. This has prompted investigations aimed at developing advanced and novel antimicrobial approaches that could effectively overcome the shortcomings associated with conventional antibiotic therapy. Studies are ongoing to develop effective curative strategies ranging from the use of peptides, small molecules, nanoparticles to bacteriophages, sonic waves, and light energy targeting various structural and physiological aspects of biofilms. In photodynamic therapy, a light source of a specific wavelength is used to irradiate non-toxic photosensitizers such as tetrapyrroles, synthetic dyes or, naturally occurring compounds to generate reactive oxygen species that can exert a lethal effect on the microbe especially by disrupting the biofilm. The photosensitizer preferentially binds to and accumulates in the microbial cells without causing any damage to the host tissue. Currently, photodynamic therapy is increasingly being used for the treatment of oral caries and dental plaque, chronic wound infections, infected diabetic foot ulcers, cystic fibrosis, chronic sinusitis, implant device-associated infections, etc. This approach is recognized as safe, as it is non-toxic and minimally invasive, making it a reliable, realistic, and promising therapeutic strategy for reducing the microbial burden and biofilm formation in chronic infections. In this review article, we discuss the current and future potential strategies of utilizing photodynamic therapy to extend our ability to impede and eliminate biofilms in various medical conditions.

In vitro synergistic activity of colistin and ceftazidime or ciprofloxacin against multidrug-resistant clinical strains of Pseudomonas aeruginosa.

Infections caused by multidrug resistant (MDR) Pseudomonas aeruginosa are difficult to treat. Antibiotic development is dwindling in recent years. In order to develop new alternate therapies antimicrobial activity of different antibiotic combinations are being studied in vitro and in vivo. Sub-inhibitory concentrations of colistin were tested in combination with ceftazidime or ciprofloxacin by the checkerboard method against 25 MDR strains of P. aeruginosa. Synergy was observed for ceftazidime or ciprofloxacin antibiotic combinations with colistin among 73.3% of MDR3 (R(AMK, GEN, TOB) R(CAZ) R(CIP)) strains and 100% of MDR4 (R(AMK, GEN, TOB) R(CAZ) R(CIP) R(TZP)) strains. 6.6% strains of MDR3 and 14.3% strains of MDR5 (R(AMK, GEN, TOB) R(CAZ) R(CIP) R(TZP) R(IPM)) phenotypes were inhibited by colistin and ceftazidime alone and 6.6% strains of MDR3 phenotypes were inhibited by colistin and ciprofloxacin alone. For the remaining strains, though synergy was not observed, significant reduction in minimum inhibitory concentration was evident. The results of this study are significant as sub-inhibitory concentrations of colistin have an advantage of reducing in vivo toxicity. These findings need further evaluation for clinical use.

Zeaxanthin biosynthesis by members of the genus Muricauda.

Zeaxanthin, a C40xanthophyll carotenoid, has potential biological applications in nutrition and human health. In this study we characterized carotenoid composition in 5 taxonomically related marine bacterial isolates from the genus Muricauda. The pigment was characterized using high performance liquid chromatography (HPLC) and mass spectrometry, which confirmed the presence of all-trans-zeaxanthin. Muricauda strains produced zeaxanthin as a predominant carotenoid. M. flavescens JCM 11812(T) produced highest yield (4.4 +/- 0.2 mg L(-1)) when cultured on marine broth at 32 degrees C for 72 h. This is the first report on the presence of zeaxanthin among the majority of species from the genus Muricauda.

Zeaxanthin production by novel marine isolates from coastal sand of India and its antioxidant properties.

Zeaxanthin carotenoids are class of commercially important natural products and diverse biomolecules produced by plants and many microorganisms. Bacteria often produce a cocktail of polar and nonpolar carotenoids limiting their industrial applications. Marine members of the family Flavobacteriaceae are known to produce potential carotenoids such as astaxanthin and zeaxanthin. A few bacterial species have been reported for the predominant production zeaxanthin. Here, we report the molecular identification of the zeaxanthin as a major carotenoid produced by two novel bacteria (YUAB-SO-11 and YUAB-SO-45) isolated from sandy beaches of South West Coast of India and the effect of carbon sources on the production of zeaxanthin. The strains were identified based on the 16S rRNA gene sequencing as a member of genus Muricauda. The closest relatives of YUAB-SO-11 and YUAB-SO-45 were Muricauda aquimarina (JCM 11811(T)) (98.9 %) and Muricauda olearia (JCM 15563(T)) (99.2 %), respectively, indicating that both of these strains might represent a novel species. The highest level of zeaxanthin production was achieved (YUAB-SO-11, 1.20 ± 0.11 mg g(-1)) and (YUAB-SO-45, 1.02 ± 0.13 mg g(-1)) when cultivated in marine broth supplemented with 2 % NaCl (pH 7) and incubated at 30 °C. Addition of 0.1 M glutamic acid, an intermediate of citric acid cycle, enhanced the zeaxanthin production as 18 and 14 % by the strains YUAB-SO-11 and YUAB-SO-45 respectively. The zeaxanthin showed in vitro nitric oxide scavenging, inhibition of lipid peroxidation, and 2,2-diphenyl-1-picryl hydrazyl scavenging activities higher than the commercial zeaxanthin. The results of this study suggest that two novel strains YUAB-SO-11 and YUAB-SO-45 belonging to genus Muricauda produce zeaxanthin as a predominant carotenoid, and higher production of zeaxanthin was achieved on glutamic acid supplementation. The pigment showed good in vitro antioxidant activity, which can be exploited further for commercial applications.

Bhargavaea ullalensis sp. nov., isolated from coastal sand.

A Gram-positive-staining, aerobic, non-endospore-forming bacterium, isolated from Ullal coastal sand, Mangalore, Karnataka, India, on marine agar 2216, was studied in detail for its taxonomic position. Based on 16S rRNA gene sequence similarity comparisons, strain ZMA 19(T) was grouped into the genus Bhargavaea with high 16S rRNA gene sequence similarities to all currently described species of the genus Bhargavaea, Bhargavaea cecembensis (99.3 %), Bhargavaea beijingensis (98.8 %) and Bhargavaea ginsengi (98.6 %). GyrB amino acid sequence-based analysis supported the phylogenetic position and also distinguished strain ZMA 19(T) from the three other species of the genus Bhargavaea. Amino acid sequence similarities were only 85.6 to 89.5 % between strain ZMA 19(T) and the type strains of members of the genus Bhargavaea, which shared higher similarities among each other (93.0 to 96.2 %). The chemotaxonomic characterization supported the allocation of the novel strain to the genus Bhargavaea. The major menaquinone was MK-8. The polar lipid profile contained predominantly diphosphatidylglycerol and moderate amounts of phosphatidylglycerol. The diagnostic peptidoglycan diamino acid was lysine and the polyamine pattern contained spermidine and spermine. The major fatty acids were iso- and anteiso-branched fatty acids. DNA-DNA hybridization with the types strains Bhargavaea cecembensis LMG 24411(T), Bhargavaea beijingensis DSM 19037(T) and Bhargavaea ginsengi DSM 19038(T) resulted in values (reciprocal values in parentheses) of 26 % (29 %), 18 % (15 %) and 21 % (12 %), respectively. The results of physiological and biochemical tests allowed phenotypic differentiation of strain ZMA 19(T) from all other species of the genus Bhargavaea. Thus, ZMA 19(T) represents a novel species of this genus, for which the name Bhargavaea ullalensis sp. nov. is proposed, with ZMA 19(T) ( = LMG 27071(T) = CCM 8429(T)) as the type strain.