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Constitutive expression of tumor necrosis factor-alpha in cytotoxic cells of teleosts and its role in regulation of cell-mediated cytotoxicity. Violacein from I Iodobacter i sp. 7MAnt induced IFNa expression in head kidney cells of Atlantic salmon, suggesting that these cells could induce an antiviral state. The results of the qRT-PCR showed that transcript levels of antiviral cytokine IFNa and pro-inflammatory cytokine TNF- increase significantly after 24 hr post-treatment with violacein respect to the control (NC) and DMSO with a P value <0.05 (Figure 3). Keywords: Antarctic microorganism; immunomodulatory activity; innate immunity; natural compound; violacein EN Antarctic microorganism immunomodulatory activity innate immunity natural compound violacein 485 489 5 02/10/22 20220301 NES 220301 Antarctica contains a rich microbial diversity, where the repertoire of metabolic expressions is diverse and complex. [Extracted from the article]

This study describes the optimization of a culture medium to improve protease production by Janthinobacterium sp. using response surface methodology (RSM) and comparative proteomic analysis. Using a one-variable-at-a-time approach, dextrose, Triton X-100, peptone, and pH were identified as significant factors affecting protease production. The optimized medium resulted in a 6.25-fold increase in protease activity when compared to that in the original medium. To investigate the metabolic changes in the optimized medium, extracellular and intracellular proteins were analyzed by two-dimensional gel electrophoresis. Some proteins essential to cell viability were highly expressed in the optimized medium and the outer membrane protein A was secreted at a higher level. These results can be useful for the industrial application of psychrophiles that produce cold-adapted enzymes. [ABSTRACT FROM AUTHOR]

The analysis of the cold-shock domain (CSD)-encoding genes, capB and cspA, by PCR amplification showed presence of capB in all 18 Antarctic Pseudomonas isolates, but the absence of cspA. Nucleotide sequence analysis of capB ORF from a biodegradative Pseudomonas 30/3 and its regulatory sequences including the promoter and 5′-UTR was determined and compared with the other CSD-encoding genes. Expression analysis using translational gene fusion of the putative capB promoter and its flanking sequence from Pseudomonas sp. 30/3 with lacZ′ exhibited a significant increase in β-galactosidase activity at 15 and 6°C. Unlike the expression of E. coli CspA, Pseudomonas sp. 30/3 showed a slow but steady increase of the CapB expression at 6°C. Subcellular localization of CapB at 6°C showed accumulation in and around the nucleoid whereas at 22 or 30°C, it was identified around the nucleoid as well as in the cytosol. Our study attempts to elucidate the detailed structure of capB from Pseudomonas 30/3 and the role of 5′UTR in the transcriptional regulation along with the possible role of CapB in transcription and translation suited for the cold adaptation of this bacterium in Antarctic environment. [ABSTRACT FROM AUTHOR]

• Application of a secreted protease from a filamentous fungus isolated in Antarctica. • Protease generated bioactive hydrolysates from caprine and bovine caseinate sources. • Hydrolysates active in eliminating free radicals and chelating transition metals. • Hydrolysate contains low molecular weight inhibitor of angiotensin-converting enzyme. The extracellular serine protease produced by Acremonium sp. L1-4B isolated from the Antarctic continent, was purified and used for the proteolysis of bovine and caprine sodium caseinate. Protein hydrolysates were evaluated in vitro to determine their antioxidant and antihypertensive potential, and later characterized by mass spectrometry. Bovine and caprine hydrolysates produced over 24 h showed a higher content of copper chelation (25.8 and 31.2% respectively), also at this time the ABTS+• scavenging was 65.2% (bovine sample) and 67.5% (caprine sample), and bovine caseinate hydrolysate (8 h) exhibited higher iron chelation capacity (43.1%). Statistically (p < 0.05), caprine caseinate hydrolysates showed relatively higher antioxidant potential in this study. All hydrolysates showed antihypertensive potential; however peptides released from caprine caseinate after 8 h of hydrolysis were able to inhibit 75% of angiotensin-converting enzyme (ACE) activity. Nano-ESI-Q-TOF-MS/MS analysis prospected a total of 23 different peptide sequences in the bovine hydrolysate fraction, originated from the α S1- and β -casein chain, whilst in caprine hydrolysate, 31 sequences were detected, all from β -casein. The low molecular weight bovine and caprine hydrolysates obtained in this research have the potential to act in the prevention of disorders caused by oxidative reactions and in the regulation of blood pressure. These findings support the development of new functional food and nutraceutical formulations. [ABSTRACT FROM AUTHOR]