Stabilization of a Photoradiated Naphthalene Diimide-Based Organic Radical Anion Inside a Peptide-Based Gel Matrix with an Improvement of Optoelectronic Properties.

An amino acid-conjugated naphthalene diimide (NDI)-based highly red fluorescent radical anion has been found in a water medium under the photoradiated condition. This molecule has failed to form the radical anion in the monomeric state; however, the J aggregation in the aqueous medium has ensured the formation of radical anion in the ambient condition after the irradiation of both sunlight and UV light exposure. Electron paramagnetic resonance (EPR) studies clearly suggest the formation of radical anions. Herein, the stability of the radical anion in the aqueous medium is only a few minutes as a small amount of shaking is enough to quench the radical anion in the solution state. Furthermore, the incorporation of this molecule into a peptide-based hydrogel matrix and the consequent photoirradiation have not only helped to develop radical anion in the gel matrix but also increased the enormous stability of the radical anion inside the hydrogel matrix even for 30 days. It is envisaged that the formation of the radical anion within the gel matrix prevents the free movement of the NDI molecules and restricts the diffusion of molecular oxygen in the system, which leads to the stability of the radical anions in the gel. Moreover, the stability of the radical anion within the gel has helped to enhance the conductivity of the hybrid gel to a great extent. Interestingly, the radical anion-containing hybrid hydrogel has shown a potential photoswitching property.

Carbon Dot as Visible-Light Photoredox Catalysts for a Myriad of Organic Transformations.

Metal-free catalysts for various organic transformations are of high demand now. In this study, we present a new carbon dot as an efficient metal-free nanophotocatalyst for carrying out a series of organic bond formation reactions. Using a single photocatalyst carbon dot, Csp2-Csp2, Csp2-B, Csp2-S, Csp2-Se, and C-P bond formation reactions were performed with a high yield of the corresponding products. Moreover, Csp2-H activation of the aromatic ring was achieved by merging the carbon dot photocatalyst with a transition metal. Interestingly, these carbon nanodot-based catalysts show good recyclability a few times without any significant loss of catalytic activity. The development of catalytic systems based on carbon dots has its merits vested in the advantageous properties of this nanomaterial, such as a robust chemical nature and cheap cost of preparation. This report demonstrates that a carbon dot indeed holds the potential to replace expensive metal-based catalysts as well as organic dyes in five different photoredox reactions.

Yellow-Emitting Carbon Dots for Selective Fluorescence Imaging of Lipid Droplets in Living Cells.

This study shows a one-pot preparation of carbon dots by a solvothermal method in ethylene glycol. The carbon dots show yellow-colored fluorescence emission in water. The carbon dots showed distinct preference to be present in the hydrophobic environment which was evident from their efficient transfer from aqueous phase to organic phase. They were also found to locate themselves in the vesicle bilayer and micelle core. This inherent lipophilic character of these carbon dots has been successfully utilized for the selective imaging of lipid droplets inside the living cells. The selective imaging of lipid droplets was confirmed by similar staining patterns with other staining dyes and the starvation study.

Consequences of physical disturbance by tadpoles and snails on chironomid larvae.

Indirect interactions among community members impact on organisms. The effects of two snails, banded pond snail, Bellamya bengalensis (Lamarck), and Red-rimmed melania, Melanoides tuberculata (Müller), and tadpoles of Asian common toad, Duttaphrynus melanostictus (Schneider), on nonbiting midge larvae, Chironomus striatipennis Kieffer, were observed in experimental microcosm. Decrease in tube number and tube length of midge larvae was observed compared to control condition due to introduction of selected above mentioned organisms. The direct effects of non-predator organisms on the midge larvae are due to physical disturbance that destroys their tubes. This may result in vulnerability of midge larvae to predators in the wild. So the community structure may be altered by indirect effects, where one or more species, through their direct disturbance, indirectly change the abundance of other species.

Monopelopia mongpuense sp. n., a phytotelmata midge from sub-Himalayan region of India (Diptera: Chironomidae: Tanypodinae).

Immature and adult stages of Monopelopia mongpuense sp. n. from phytotelmata of Cedrus deodara (Lamb.) in Darjeeling are described along with biological notes. Key to the adult males of all species of the genus Monopelopia Fittkau is also presented. This genus is recorded for the first from Indian subcontinent.

Rapid targeting and imaging of mitochondria via carbon dots using an amino acid-based amphiphile as a carrier.

Green-fluorescent biocompatible carbon dots with a quantum yield of 40% were successfully synthesized through a solvothermal process and then they are comprehensively characterized. The carbon dots showed a negatively charged surface owing to the presence of carboxylic groups. This negative surface charge hinders the effective targeting and imaging of mitochondria. To address this limitation, a new approach is developed in this study. An amphiphile containing phenylalanine, with a positively charged polar head consisting of triphenylphosphine and a hydrophobic aliphatic tail, was designed, synthesized, purified, and characterized. This amphiphile formed spherical micelle-type nanostructures in an aqueous medium in the aggregated state. Although these nanoprobes lack inherent fluorescence, they exhibited the capability to image mitochondria when their spherical micelle-type nanostructures were decorated with negatively charged fluorescent nanocarbon dots in both cancerous (KB cells) and non-cancerous (CHO cells) cell lines. Notably, carbon dots without the amphiphile failed to penetrate the cell membrane as they exhibited significantly low emission inside the cell. This study extensively explored the cell entry mechanism of the hybrid nanoprobes. The photophysical changes and the interaction between the negatively charged carbon dots and the positively charged nanospheres of the amphiphile were also analyzed in this study.

Three new species of Forcipomyia (Lepidohelea) (Diptera: Ceratopogonidae) from West Bengal, India.

Three new species of the subgenus Lepidohelea Kieffer, 1917 of the genus Forcipomyia were described from the northern region of West Bengal based on morphological data. Forcipomyia (L.) inflatistyla sp. n. was collected from the Dooars region (Jayanti, near the Core area of Buxa Tiger Reserve), while two new species F. (L.) ranula and F. (L.) sulcoa were procured from Kalimpong in the Eastern Himalaya. Discovery of the three new species raises the total number of species of the genus Forcipomyia to 86 in India. A key to the Indian species of Lepidohelea is also provided.

Taxonomic studies on Harnischia complex from India (Diptera: Chironomidae).

Beckidia Sæther, 1979, Kloosia Kruseman, 1933, Parachironomus Lenz, 1921 and Saetheria Jackson, 1977 of the Harnischia complex are four newly recorded genera in India. Beckidia inflata sp. n., Kloosia incurva sp.n., Parachironomus salsus sp.n., Saetheria circinata sp.n., and Harnischia bulbosa sp.n. are described and illustrated. Microchironomus ishii Sasa, 1987, as a new record, is re-described and illustrated based on males. Three species, Paracladopelma nigrotibia (Bhattacharya, Dutta & Chaudhuri, 1985), Cryptotendipes acutus (Goetghebuer, 1936), and Saetheria sacculifera (Chaudhuri & Chattopadhyay, 1990) are proposed here as new combinations. Other Indian species of little known genera within the Harnischia complex are also re-examined and synonymisation is made. Molecular barcodes of five new species Beckidia inflata sp.n., Kloosia incurva sp.n., Parachironomus salsus sp.n., Saetheria circinata sp.n., and Harnischia bulbosa sp.n. and three known species of the Harnischia complex are also provided. Separate world keys of adult males of five genera are also designed here.

A new species of the genus Tridactylophagus Subramaniam, 1932 from West Bengal, India with a tentative phylogeny and world key to known males (Strepsiptera: Halictophagidae).

A new species of the genus Tridactylophagus Subramaniam is described and illustrated from West Bengal, India. The new species, T. sufflatus differs from other members of Tridactylophagus by having a flattened, fist-shaped first tarsomere in forelegs and a slightly bulged out antennomere IV on the distal end with a sensory spot on one side. Molecular barcoding of the new species is done. Cladistic analysis and a revised world key of the males of the genus Tridactylophagus are also provided.

Coriophagus chaudhuri sp. n. (Strepsiptera: Halictophagidae: Coriophaginae): a male strepsipteran from Jharkhand, India with a tentative phylogeny and world key to known males.

A new species of the genus Coriophagus Kinzelbach is described from the state of Jharkhand, India raising two in number from India. The new species, Coriophagus chaudhuri differs from other members of the genus in wing venation with base of R3 touching the subapex of R4, and flattened, oval-shaped foretarsomere I. The DNA barcoding of the new species has also been attempted here. An attempt is made to hypothesise the possible phylogenetic relationship of the males of the genus. A world key to known males of the genus is provided.

Surface modification of carbon dots via peptide covalent conjugation.

Surface modification of carbon dots via covalent conjugation with a dipeptide resulted in a dramatic change in the fluorescence emission from green to red. The hydrophobic peptide units linked to the surface of the modified carbon dots helped them to aggregate by generating a nanodot-fabricated nanofibrous network. This nanofibrous network showed excellent electrical conductivity and photo-switching behavior, better than those of the non-aggregated dots.

First records of three genera, Cyphomella Sther, 1977, Olecryptotendipes Zorina, 2007 and Robackia Sther, 1977 of the Harnischia complex from India with description of O. extentus sp. n., O. obtunsus sp. n. and R. aequilongia sp. n. (Diptera: Chironomidae).

Three genera, Cyphomella Sther, 1977, Olecryptotendipes Zorina, 2007 and Robackia Sther, 1977, of the Harnischia complex are recorded for the first time from India. Two new species of Olecryptotendipes and one new species of Robackia are described on the basis of adult males. Cyphomella camelus (Kieffer, 1955), described from Afrotropical and Palaearctic regions, is recorded for the first time from India and its description is supplemented. The molecular barcodes of three species, O. obtunsus sp. n., C. camelus and R. aequilongia sp. n., are also provided. Revised world keys to the adult males of the Olecryptotendipes and Robackia are also provided.

Two new species of Demicryptochironomus Lenz, 1941 from India with tentative phylogenetic relationship and a revised world key to known males (Diptera: Chironomidae).

Demicryptochironomus (s. str.) praeacutus sp. n. and D. (Irmakia) dividuus sp. n. are described based on adult males from India. A revised world key to the known males of the genus and molecular barcodes of both species are provided. A tentative phylogenetic relationship based on morphological characters of adult males of the genus Demicryptochironomus Lenz is also proposed.

Two new species of Pseudosmittia Edwards, 1932 from India with a key to Oriental species adult males (Diptera: Chironomidae: Orthocladiinae).

In this study, we described and illustrated two new species, Pseudosmittia luna and Pseudosmittia valida based on the adult males from the plains of West Bengal, India. A DNA barcode of Pseudosmittia luna sp. n. compared with selected congeneric sequences from NCBI GenBank, indicates that the species is sister to an unknown species with accession number MG301870. Additionally, we provided a key for the adult males of the Oriental species of the genus.

On a new species of the genus Zavrelimyia Fittkau, 1962 (Diptera: Chironomidae) from India with cladistic relationship and a world key to the known males.

The adult male of Zavrelimyia (Paramerina) falcata sp.n. is described and illustrated from India. The DNA barcode of this new species is provided. The original description of Zavrelimyia (P.) valida (Paul, Hazra and Mazumdar, 2013) is corrected. The subgenus Schineriella Murray and Fittkau, 1988 of Zavrelimyia Fittkau is recorded in the Oriental region. A cladistic relationship of the species of Zavrelimyia Fittkau and a world key to the adult males of the genus Zavrelimyia Fittkau are provided.

Revision of the Oriental species of Polypedilum Kieffer (Diptera: Chironomidae) with their phylogenetic relationship.

Imagines and pupae of new species Polypedilum (Pentapedilum) retusum are described from India. Three species, P. (Polypedilum) tamanigrum Sasa, 1983, P. (Pentapedilum) anale (Freeman, 1954), and P. (Tripodura) conghuaense Zhang, Song, Qi and Wang, 2016 with pupa are recorded firstly in the subcontinent. Hypopygia of P. (P.) ascium Chaudhuri, Guha and Das Gupta, 1981, P. (T.) conghuaense, P. (T.) lineatum Chaudhuri, Guha and Das Gupta, 1981 and P. (P.) nudiceps Chaudhuri, Guha and Das Gupta, 1981 are redescribed. Polypedilum (P.) exterflexum Hazra, Sanyal and Brahma, 2015, P. clavipennae Hazra, Sanyal and Brahma, 2015 and P. aduncum Konar and Hazra, 2017 are proposed here to transfer to the genus Stictochironomus Kieffer, 1919. Polypedilum (P.) insolitum Chaudhuri, Guha and Das Gupta, 1981 is here stated as junior synonym of Zavreliella marmorata (Wulp, 1859). In addition, some biogeographic and taxonomic remarks including DNA barcoding for selected species are given. Cladistic analysis of the Oriental species of Polypedilum Kieffer is made to hypothesise their possible relationship. A new dichotomous key of the Oriental species of Polypedilum is presented here.

A new species of the genus Larsia Fittkau (Diptera: Chironomidae) from India, with cladistic analysis and a world key to the known males.

A new species of the genus Larsia Fittkau, 1962 is described based on the adult males. It is the first species of this genus reported from India and second member from the Oriental region. The DNA barcode of this new species is provided. The cladistic analysis of the known species of Larsia using morphological data of both immature and male adult stages have supported monophyly of the genus. A world key to the known males of the genus Larsia is presented here.

A new species of the genus Cryptotendipes Beck et Beck, 1969 (Diptera: Chironomidae) from India, with a world key to the males and tentative phylogenetic relationship.

A new species of the genus Cryptotendipes Beck et Beck is described on the basis of adult male. It is the third species from India and ninth from the Oriental region. The Chinese species, C. nodus Yan, Tang et Wang, 2005 is recorded firstly from India. The molecular barcoding of two species, Cryptotendipes disparilis Pal et Hazra, 2018 and C. nodus is provided. Additional information and revision of two Indian species Cryptotendipes aculeatus Pal et Hazra, 2018 and C. disparilis Pal et Hazra, 2018 are furnished for erroneous description. A tentative cladistic relationship based on the morphological data of adult males and a revised world key to the adult males of the genus Cryptotendipes are also provided.

Salt-bridges in the microenvironment of stable protein structures.

Salt-bridges (sb) play an important role in the folding and stability of proteins. This is deduced from the evaluation of net energy in the microenvironments (ME, residues that are 4 Å away from positive and negative partners of salt-bridge and interact with them). MEs act as a determinant of net-energy due to the intrinsic features in the sequence. The stability of extremophilic proteins is due to the presence of favorable residues at the ME without any unfavorable residues. We studied a dataset of four structures from the protein data bank (PDB) and a homology model (1HM5) to gain insights on this issue. Data shows that the presence of isolated charges and polar residues in the core of extremophilic proteins helps in the formation of stable salt-bridges with reduced desolvation. Thus, site-specific mutations with favorable residues at the ME will help to develop thermo stable proteins with strong salt bridges.