Study of Potential Application of Cyanobacteria Leptolyngbya Valderiana in Skin Cosmeceuticals

Skin is the outermost cover and first line of defense of the human body. Skin cosmeceuticals are therapeutic agents used to maintain flawless skin and prevent skin disorders. Considering the ill effects of synthetic active agents, natural metabolites are preferred for skincare. Cyanobacterium was known to produce various secondary metabolites with therapeutic potential. This study focuses on screening whole-cell extract of Leptolyngbya valderiana for skincare. Isolation and identification of cyanobacteria were made. The whole-cell extract of Leptolyngbya valderiana was studied for its metabolite profile, mainly for proteins, carbohydrate, and lipid content. Screening of whole-cell extract was carried out for its (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) (ABTS) radical scavenging ability and UV absorption potential. The antimicrobial effect of extracts was determined by agar cup and minimum inhibitory concentration (MIC) method using salicylic acid as a standard. Skin whitening potential was determined using tyrosinase inhibition assay. Leptolyngbya valderiana was isolated from the tree bark and selected for further study. The extract of Leptolyngbya valderiana was found to have 25.22% proteins, 36.65 % carbohydrates and 35.97% lipids. The extract was found to have antioxidant potential with 96.55% ABTS radical scavenging potential. Antimicrobial potency of the extract against Staphylococcus aureus ATCC 6538, Propionibacterium acne MTCC 1351, Candida albicans ATCC 10231 was equivalent to salicylic acid. The test extract was found to inhibit the tyrosinase enzyme by 43.46%. The test extract is rich in proteins, carbohydrates, and lipids. The extract has significant antioxidant potential, antimicrobial efficiency, ability to absorb ultraviolet B and ultraviolet A region, tyrosinase inhibition potential indicative photoprotective, and skin whitening potential. The isolate Leptolyngbya valderiana has a promising potential for skin cosmeceuticals.

Impact of Losing hRpn13 Pru or UCHL5 on Proteasome Clearance of Ubiquitinated Proteins and RA190 Cytotoxicity

ABSTRACT hRpn13/ADRM1 links substrate recruitment with deubiquitination at the proteasome through its proteasome- and ubiquitin-binding Pru domain and DEUBAD domain, which binds and activates deubiquitinating enzyme (DUB) UCHL5/Uch37. Here, we edit the HCT116 colorectal cancer cell line to delete part of the hRpn13 Pru, producing cells that express truncated hRpn13 (trRpn13), which is competent for UCHL5 binding but defective for proteasome interaction. trRpn13 cells demonstrate reduced levels of proteasome-bound ubiquitinated proteins, indicating that the loss of hRpn13 function at proteasomes cannot be fully compensated for by the two other dedicated substrate receptors (hRpn1 and hRpn10). Previous studies indicated that the loss of full-length hRpn13 causes a corresponding reduction of UCHL5. We find UCHL5 levels unaltered in trRpn13 cells, but hRpn11 is elevated in ΔhRpn13 and trRpn13 cells, perhaps from cell stress. Despite the ∼90 DUBs in human cells, including two others in addition to UCHL5 at the proteasome, we found deletion of UCHL5 from HCT116 cells to cause increased levels of ubiquitinated proteins in whole-cell extract and at proteasomes, suggesting that UCHL5 activity cannot be fully assumed by other DUBs. We also report anticancer molecule RA190, which binds covalently to hRpn13 and UCHL5, to require hRpn13 Pru and not UCHL5 for cytotoxicity.

RNA processing machineries in Archaea: the 5′-3′ exoribonuclease aRNase J of the β-CASP family is engaged specifically with the helicase ASH-Ski2 and the 3′-5′ exoribonucleolytic RNA exosome machinery

A network of RNA helicases, endoribonucleases and exoribonucleases regulates the quantity and quality of cellular RNAs. To date, mechanistic studies focussed on bacterial and eukaryal systems due to the challenge of identifying the main drivers of RNA decay and processing in Archaea. Here, our data support that aRNase J, a 5′-3′ exoribonuclease of the β-CASP family conserved in Euryarchaeota, engages specifically with a Ski2-like helicase and the RNA exosome to potentially exert control over RNA surveillance, at the vicinity of the ribosome. Proteomic landscapes and direct protein–protein interaction analyses, strengthened by comprehensive phylogenomic studies demonstrated that aRNase J interplay with ASH-Ski2 and a cap exosome subunit. Finally, Thermococcus barophilus whole-cell extract fractionation experiments provide evidences that an aRNase J/ASH-Ski2 complex might exist in vivo and hint at an association of aRNase J with the ribosome that is emphasised in absence of ASH-Ski2. Whilst aRNase J homologues are found among bacteria, the RNA exosome and the Ski2-like RNA helicase have eukaryotic homologues, underlining the mosaic aspect of archaeal RNA machines. Altogether, these results suggest a fundamental role of β-CASP RNase/helicase complex in archaeal RNA metabolism.

Carbon source regulates polysaccharide capsule biosynthesis in Streptococcus pneumoniae

The exopolysaccharide capsule of Streptococcus pneumoniae is an important virulence factor, but the mechanisms that regulate capsule thickness are not fully understood. Here, we investigated the effects of various exogenously supplied carbohydrates on capsule production and gene expression in several pneumococcal serotypes. Microscopy analyses indicated a near absence of the capsular polysaccharide (CPS) when S. pneumoniae was grown on fructose. Moreover, serotype 7F pneumococci produced much less CPS than strains of other serotypes (6B, 6C, 9V, 15, and 23F) when grown on glucose or sucrose. RNA-sequencing revealed carbon source-dependent regulation of distinct genes of WT strains and capsule-switch mutants of serotypes 6B and 7F, but could not explain the mechanism of capsule thickness regulation. In contrast, 31P NMR of whole-cell extract from capsule-knockout strains (Δcps) clearly revealed the accumulation or absence of capsule precursor metabolites when cells were grown on glucose or fructose, respectively. This finding suggests that fructose uptake mainly results in intracellular fructose 1-phosphate, which is not converted to CPS precursors. In addition, serotype 7F strains accumulated more precursors than did 6B strains, indicating less efficient conversion of precursor metabolites into the CPS in 7F, in line with its thinner capsule. Finally, isotopologue sucrose labeling and NMR analyses revealed that the uptake of the labeled fructose subunit into the capsule is <10% that of glucose. Our findings on the effects of carbon sources on CPS production in different S. pneumoniae serotypes may contribute to a better understanding of pneumococcal diseases and could inform future therapeutic approaches.

Netrin-1 Peptide Is a Chemorepellent in Tetrahymena thermophila

Netrin-1 is a highly conserved, pleiotropic signaling molecule that can serve as a neuronal chemorepellent during vertebrate development. In vertebrates, chemorepellent signaling is mediated through the tyrosine kinase, src-1, and the tyrosine phosphatase, shp-2. Tetrahymena thermophila has been used as a model system for chemorepellent signaling because its avoidance response is easily characterized under a light microscope. Our experiments showed that netrin-1 peptide is a chemorepellent in T. thermophila at micromolar concentrations. T. thermophila adapts to netrin-1 over a time course of about 10 minutes. Netrin-adapted cells still avoid GTP, PACAP-38, and nociceptin, suggesting that netrin does not use the same signaling machinery as any of these other repellents. Avoidance of netrin-1 peptide was effectively eliminated by the addition of the tyrosine kinase inhibitor, genistein, to the assay buffer; however, immunostaining using an anti-phosphotyrosine antibody showed similar fluorescence levels in control and netrin-1 exposed cells, suggesting that tyrosine phosphorylation is not required for signaling to occur. In addition, ELISA indicates that a netrin-like peptide is present in both whole cell extract and secreted protein obtained from Tetrahymena thermophila. Further study will be required in order to fully elucidate the signaling mechanism of netrin-1 peptide in this organism.

Bactericidal activity of the sera of rabbits immunized with Vibrio cholerae O1 whole cell extract

Vibrio cholerae serotype O1 causes diarrhea in many developing countries around the world. In most cases, cholera patients pose some sorts of immunity against the naturally occurring infection. In the present study, the bactericidal activity of the sera of rabbit immunized with whole cell extract of Vibrio cholerae O1 was investigated. The protein profile of the serotype exhibited 20 types of proteins of distinguished molecular weights. The western blot analysis revealed at least 10 proteins to be immunogenic. Interestingly, decomplementation of the sera was found to abolish the bactericidal activity. The bactericidal activity of non immunized rabbit sera was also investigated and the results revealed that the immunized sera were more effective than that of non immunized one. DOI: http://dx.doi.org/10.3329/sjm.v2i1.15209 Stamford Journal of Microbiology, Vol.2(1) 2012: 24-27