Molecular data based revision of Leptolyngbya, the largest polyphyletic genus of the family Leptolyngbyaceae (Synechococcales) is imperative. Polyphasic approach to the taxonomic analysis of two (AP9F and AP25) cyanobacteria, tentatively designated positions in the “LPP-group” is described. Cell shapes of AP9F and AP25 were highly elongated whereas the cells of the reference strains (Leptolyngbya boryana and Nodosilinea nodulosa) were occasionally elongated to isodiametrical. Terminal cells of AP9F and AP25 appeared as flattened corners (not rounded), which was different from other Leptolyngbyaceae members. 16S rRNA gene sequences of AP9F (1366 bp) and AP25 (1408 bp) showed 95% and 92% similarities respectively with the non-redundant nucleotide sequences of their closest relatives of the Leptolyngbya genus. Test strains were located in the phylogenetic tree in a clade different from the ones containing the type species. A single operon having both tRNAile and tRNAala genes were present in the ITS regions of AP9F and AP25 compared to two operons in the ITS region of the genera Leptolyngbya and Nodosilinea: one having both tRNAile and tRNAala genes and another lacking both the genes. The secondary structures of the traditionally conservative D-stem region as well as the Box B helix and V3 regions of the ITS operons significantly varied between the test strains and also when compared with the corresponding sequences of L. boryana and N. nodulosa. Molecular phylogenetic and morphological data suggested AP9F and AP25 to be monophyletic taxa for which the names Euryhalinema mangrovii gen. nov., sp. nov. and Leptoelongatus litoralis gen. nov., sp. nov. are proposed respectively.
Taxonomic characterization by a polyphasic approach was carried out on two cyanobacteria, AP17 and AP24 isolated from soil biofilms of two separate islands, Lothian and Sagar respectively, of the Indian Sundarbans. The strains were studied morphologically by light microscopy, scanning and transmission electron microscopy. Growth responses to various salinities were recorded. Molecular data included sequencing and phylogenetic study of the 16S rRNA gene as well as analysis of the 14 regions of the 16S-23S ITS regions. Morphologically the strains were found to be non-heterocytous, having attenuated trichomes with a narrow, bent terminal cell without any crosswalls. Strains under investigation shared 99–100% 16S rRNA gene sequence similarity with Oxynema thaianum CCALA960, the type species of the novel Oxynema genus, recently separated from the Phormidium-Group I genus. However, cross walls in the apical portion of AP17 and AP24 were totally absent while the same was present in CCALA960. Additionally, optimal growth of AP17 and AP24 was recorded in 5–8% salinity and salinity above 14% inhibited growth of both strains, which were isolated from an intertidal environment; whereas O. thaianum CCALA960 which was found in a hypersaline environment could grow at 40% salinity. Insertion of 9 nucleotides in the D2 with spacer region, insertion of 2 nucleotides in the pre Box B spacer region, deletion of 2 nucleotides in the post Box B spacer region, deletion of 8 nucleotides in the D4 region, deletion of 8 nucleotides in V3 region and insertion of 2 nucleotides in the D5 region of the ITS sequences of AP17 and AP24 were observed in comparison to the analogous regions of CCALA960. Structural details of Box B helices of AP17 and AP24 revealed that although their lengths were identical with the reference, their sequences were completely different from CCALA960. Four nucleotide substitutions were observed in different positions in the Box B helix of O. thaianum CCALA960. Secondary structures of the V3 regions of AP17 and AP24 (containing 51 nucleotides) showed a small terminal bulge and a bigger bilateral bulge while the analogous structure of O. thaianum CCALA 960 (comprising of 59 nucleotides) showed one additional bilateral bulge in comparison to AP17 and AP24. Therefore, based on morphological, ecological and molecular differences in comparison to O. thaianum CCALA960, isolates AP17 and AP24 should be considered as a second novel species in the Oxynema genus, for which the name Oxynema aestuarii sp. nov. is proposed.
Fiaud's acid (trans-1-hydroxy-2,5-diphenylphospholane 1-oxide), a phospholane-based phosphinic acid, is introduced as an efficient chiral Brønsted acid catalyst that mediates the asymmetric Friedel-Crafts alkylation of indoles with 2-butene-1,4-diones. With a catalyst loading of 10 mol %, the reaction proceeded smoothly to afford 2-(indol-3-yl)butane-1,4-diones in high yield (up to 82%) and high enantioselectivity (up to 91% ee, one such product showed enhanced ee of 98% after recrystallization). The reaction conditions are sufficiently mild to tolerate sensitive functionality at room temperature and are therefore suitable for the synthesis of complex targets.
A series of heterocyclic C5-Curcuminoid (PJ1–PJ6) having large Stokes shift (Δλ = 104–173 nm) have been synthesized under the microwave irradiation and PJ1 has been utilized for selective detection of thiols in A375 cells and apoptosis in AGS cells.
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