The filamentous cyanobacterium Fischerella muscicola TISTR8215 was tested for the presence of ultraviolet (UV)‐absorbing mycosporine‐like amino acids (MAAs) and their induction by UV radiation. ...Reverse‐phase high performance liquid chromatographic coupled with photodiode‐array detection studies revealed the presence of a MAA having an absorption maximum at 332 nm and a retention time of around 16.1 min. Based on absorption maximum, the compound was designated as M‐332. This is the first report for the occurrence of a MAA and its inducibility as influenced by UV radiation in Fischerella strains studied so far. Photosynthetically active radiation (PAR) had no significant impact on MAA induction. PAR + UV‐A radiation significantly induced the synthesis of M‐332; however, PAR + UV‐A + UV‐B radiation conferred highest impact on MAA synthesis. The cultures exposed to alternate light and dark conditions showed the induction of M‐332 synthesis mostly during the light period in contrast to the decreased levels of M‐322 during the dark period suggesting a circadian induction of its synthesis. Overall results indicate that F. muscicola may protect itself from deleterious short wavelength UV radiation by synthesizing the photoprotective compounds particularly during summer time in its natural brightly‐lit habitats.
Summary The filamentous cyanobacterium Fischerella muscicolaTISTR8215 was tested for the presence of ultraviolet (UV)-absorbing mycosporine-like amino acids (MAAs) and their induction by UV ...radiation. Reverse-phase high performance liquid chromatographic coupled with photodiode-array detection studies revealed the presence of a MAA having an absorption maximum at 332nm and a retention time of around 16.1min. Based on absorption maximum, the compound was designated as M-332. This is the first report for the occurrence of a MAA and its inducibility as influenced by UV radiation in Fischerella strains studied so far. Photosynthetically active radiation (PAR) had no significant impact on MAA induction. PAR+UV-A radiation significantly induced the synthesis of M-332; however, PAR+UV-A+UV-B radiation conferred highest impact on MAA synthesis. The cultures exposed to alternate light and dark conditions showed the induction of M-332 synthesis mostly during the light period in contrast to the decreased levels of M-322 during the dark period suggesting a circadian induction of its synthesis. Overall results indicate that F.muscicola may protect itself from deleterious short wavelength UV radiation by synthesizing the photoprotective compounds particularly during summer time in its natural brightly-lit habitats.
Phylogenetic analysis of 4 cyanobacterial strains isolated from hot springs in Rajgir, India, was carried out using the 16S rRNA gene (1400 bp). These strains were identified as members of ...Chroococcales (Cyanothece sp. strain HKAR-1) and Nostocales (Nostoc sp. strain HKAR-2, Scytonema sp. strain HKAR-3, and Rivularia sp. strain HKAR-4). Furthermore, we evaluated the presence of ultraviolet-screening and (or) photoprotective compounds, such as mycosporine-like amino acids (MAAs) and scytonemin, in these cyanobacteria by using high-performance liquid chromatography. Well-characterized MAAs, including the critical and highly polar compounds shinorine, porphyra-334, and mycosporine-glycine, as well as several unknown MAAs, were found in these hot-spring-inhabiting microorganisms. The presence of scytonemin was detected only in Scytonema sp. strain HKAR-3 and Rivularia sp. strain HKAR-4. The results indicate that hot spring cyanobacteria, namely Cyanothece, Nostoc, Scytonema, and Rivularia, belonging to different groups possess various photoprotective compounds to cope up with the negative impacts of damaging radiations.
The genomic as well as structural relationship of phycobiliproteins (PBPs) in different cyanobacterial species are determined by nucleotides as well as amino acid composition. The genomic GC ...constituents influence the amino acid variability and codon usage of particular subunit of PBPs. We have analyzed 11 cyanobacterial species to explore the variation of amino acids and causal relationship between GC constituents and codon usage. The study at the first, second and third levels of GC content showed relatively more amino acid variability on the levels of G3+C3 position in comparison to the first and second positions. The amino acid encoded GC rich level including G rich and C rich or both correlate the codon variability and amino acid availability. The fluctuation in amino acids such as Arg, Ala, His, Asp, Gly, Leu and Glu in α and β subunits was observed at G1C1 position; however, fluctuation in other amino acids such as Ser, Thr, Cys and Trp was observed at G2C2 position. The coding selection pressure of amino acids such as Ala, Thr, Tyr, Asp, Gly, Ile, Leu, Asn, and Ser in α and β subunits of PBPs was more elaborated at G3C3 position. In this study, we observed that each subunit of PBPs is codon specific for particular amino acid. These results suggest that genomic constraint linked with GC constituents selects the codon for particular amino acids and furthermore, the codon level study may be a novel approach to explore many problems associated with genomics and proteomics of cyanobacteria.
•Percentage amino acid variability in phycobiliproteins (PBPs) was identified.•Statistical correlation of all GC levels and gene of PBPs subunits was determined.•Codon distribution in amino acid at GC levels in subunits of PBPs was identified.•PBPs gene expressed amino acid mainly comes from G3C3 position.
Continuous depletion of the stratospheric ozone layer has resulted in an increase in ultraviolet-B (UV-B; 280-315 nm) radiation on the earth's surface which inhibits photochemical and photobiological ...processes. However, certain photosynthetic organisms have evolved mechanisms to counteract the toxicity of ultraviolet or high photosynthetically active radiation by synthesizing the UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin besides the repair of UV-induced damage of DNA and accumulation of carotenoids and detoxifying enzymes or radical quenchers and antioxidants. Chemical structure of various MAAs, their possible biochemical routes of synthesis and role as photoprotective compounds in various organisms are discussed.
In the original publication, under the subtitle
Recovery: fluorescence recovery protein (FRP)
, paragraph 4 the text section enclosed in quotation marks does not occur in one of the original ...publications cited (Sluchanko et al. 2017a, b).
► UV-B radiation affects the growth and genome integrity. ► UV-B radiation induces the formation of T<>T CPDs and DNA strand breaks. ► Light quality and temperature play an important role in ...photoreactivation. ► Blue light is most effective in photoreactivation.
The impact of simulated solar radiation on DNA and the mitigation of DNA-damaging effects by photoreactivation was studied in a cyanobacterium
Anabaena variabilis PCC 7937. Cultures were irradiated under 295, 320 and 395
nm cut-off filters as well as seven other filters such as WG 280, WG 295, WG 305, WG 320, WG 335, WG 345 and GG 400. Growth of the test organism was found to be affected mostly under UV-B radiation as compared to PAR and PAR
+
UV-A radiations. Amplification of 16s rDNA and RAPD profile was significantly affected following exposure of genomic DNA to UV-B radiation. The formation of T<>T CPDs was recorded only in the cultures irradiated with UV-B radiation (i.e., under 295
nm as well as under WG 280, WG 295 and WG 305
nm cut-off filters), but maximum yield was found under 280
nm cut-off filter. Furthermore, the considerable induction of thymine dimers was observed with increasing UV-irradiation times. Fluorometric analysis of DNA unwinding (FADU) assay for UV-induced DNA strand breaks exhibited the maximum loss in the percentage of dsDNA under UV-B radiation followed by UV-A and PAR in comparison to the light control samples. We observed that T<>T CPD repair is light-dependent, since these lesions were more efficiently removed upon exposure to visible light than in the darkness. Blue radiation was found to be the most effective in photoreactivation than any other wavebands of light. Furthermore, the rate of photoreactivation was measured under varying temperatures (10, 20 and 30
°C); the repair rate was found to be the maximum at 20
°C under white fluorescent light. Our results indicate that photoreactivation play an important role in survival of the organism under natural conditions in spite of being exposed to the UV-B component present in the solar drops.
In vitro antioxidant virtue and life-prolonging effect of phycoerythrin (PE; a pigment protein isolated from
Phormidium
sp. A09DM) have been revealed in our previous reports (Sonani et al. in Age ...36:9717,
2014a
; Sonani et al. in Process Biochem 49:1757–1766,
2014b
). It has been hypothesized that the PE expands life span of
Caenorhabditis elegans
(bears large resemblance with human aging pathways) due to its antioxidant virtue. This hypothesis is tested in present study by checking the effect of PE on intracellular reactive oxygen species (ROS) generation and associated physiological deformities using mouse and human skin fibroblasts,
C. elegans
, and
Drosophila melanogaster Oregon R
+
and by divulging PE’s structural attributes responsible for its antioxidant asset. PE treatment displayed noteworthy decrease of 67, 48, and 77 % in ROS level in mouse fibroblast (
3T3-L1
), human fibroblast, and
C. elegans N2
, respectively, arisen under chemical-induced oxidative stress. PE treatment delayed the development of paraquat-induced Alzheimer phenotype by 14.5 % in
C. elegans CL4176
. Furthermore, PE improved the locomotion of
D. melanogaster Oregon R
+
under oxidative stress with simultaneous up-regulation in super-oxide dismutase and catalase activities. The existence of 52 Glu + Asp + His + Thr residues (having metal ion sequestration capacity), 5 phycoerythrobilin chromophores (potential electron exchangers) in PE’s primary structure, and significant hydrophobic patches on the surface of its α- and β-subunits are supposed to collectively contribute in the antioxidant virtues of PE. Altogether, results support the hypothesis that it is the PE’s antioxidant asset, which is responsible for its life-prolonging effect and thus could be exploited in the therapeutics of ROS-associated abnormalities including aging and neurodegeneration in eukaryotes.
Some natural fruits have significant importance in improving health which provides many nutritional supplements essential to maintain proper metabolism with the age. In this study, phytochemical ...screening of extract (methanolic) of
arils, outer and inner peels was confirmed by the respective spot tests. Quantification of phytochemical constituents revealed the plentiful of total phenols in the outer peels in comparison to inner peels and juice whereas total flavonoids and vitamin C are abundant in inner peel and juice, respectively. High-performance liquid chromatography, Gas chromatography along with mass spectrometry and Fourier-transform infrared spectroscopy analysis revealed the presence of compound 9, 17-octadecadienal, (Z) in the outer/inner peels. A compound N-hexadecanoic acid was also observed in the outer peels. Extracts from every section of the fruits were comprehensively evaluated for their antioxidant activity. Contrary to fruit aril juice, the extracts of outer and inner peels exhibited significant and dose-dependent
antioxidant and radical-scavenging potentials. The supplementation of
extracts (PGEs) significantly enhanced the lifespan of
. The protective effect of PGEs was also observed against oxidative stress in
. Additionally, the involvement of FOXO orthologue DAF-16 dependent longevity was obtained with PGEs (outer peel and inner peel) fed TJ356 worms. Overall, the results indicate the vital role of PGEs especially the extracts of outer peels in life-saving mechanisms of
by virtue of their antioxidant asset and life-prolonging effects via
dependent Insulin signaling pathway. See also Figure 1(Fig. 1).
Rann of Kachchh (RoK) is a unique geoformation, which is exposed to dynamic environmental changes such as salinity, temperature, and nutrients throughout the year. In this study, the pooled mat ...sample was examined for the cyanobacterial community structure using culture-dependent and culture-independent approaches. Taxonomic profiling was studied using amplicon sequencing that revealed the enrichment of Pseudanabaenales and Oscillatoriales by QIIME and MG-RAST, respectively. Other abundant orders were represented by Chroococcales, Nostocales, and unclassified cyanobacteria by both approaches. Nine cyanobacterial cultures were isolated from mat samples showing 90–98% similarities with available sequences in GenBank. The culture-dependent study suggested that mat was dominated by cyanobacterial orders such as Oscillatoriales—filamentous and Chroococcales—unicellular. Our results from the culture-dependent approach also indicated that despite high similarities in gene sequences, six cyanobacteria fall into the separate clade in the phylogenetic analysis that could be signs of evolution due to an extreme environment. Cultured isolates are correlated well with abundant taxa from amplicon sequencing. Further, protein profiling was done specifically for phycobiliproteins which will be helpful to elucidate their roles in light harvesting and energy transfer mechanism in the unique environment of RoK.
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