A bio-ecologial study of Nuggikari lake in Dharwar,Mysore State,South India

Summary The bio-ecological conditions of a perennial piece of water, called Nuggikari lake in Dharwar, Mysore State, were investigated for one year from the view-point of regional limnology of South India. The lake is filled with rain water during the south-west monsoon and a part of the north-east monsoon season from a lateritic catchment area containing cultivated land. The inter-relationship existing between the physico-chemical variables and the biological conditions are discussed. The water is turbid and reddish during June to November when the majority of the algal organisms found is Chlorophyceae with a dominance of Desmids. Later, the water becomes pale-green to dark-green when blue-green algae become abundant in summer. The figures for albuminoid nitrogen and oxygen are then highest.     

An Immunocompetent Mouse Model of Zika Virus Infection

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In silico identification and characterization of stress and virulence associated repeats in Salmonella

So much genomic similarities yet causing different diseases, is like a paradox in Salmonella biology. Repeat is one of the probes that can explain such differences. Here, a comparative genomics approach is followed to identify and characterize repeats that might play role in adaptation and pathogenesis. Repeats are non-randomly distributed in the genomes except few typhoid causing strains. Perfect long repeats are rare compare to polymorphic ones and both are statistically consistent. Significant differences in repeat densities in stress related genes manifest its probable participation in survival and virulence. 573 and 1053 repeat loci have been identified which are exclusively associated with stress and virulent genes respectively. In Salmonella Typhi, an octameric VNTR locus is found in between acrD and yffB genes having more than 25 perfect copies across Salmonella Typhi but possesses only single copy in other serovars. This repeat can be used as a diagnostic probe for typhoid.     

Strategies for imaging mitophagy in high-resolution and high-throughput

The selective autophagic removal of mitochondria called mitophagy is an essential physiological signaling for clearing damaged mitochondria and thus maintains the functional integrity of mitochondria and cells. Defective mitophagy is implicated in several diseases, placing mitophagy as a target for drug development. The identification of key regulators of mitophagy as well as chemical modulators of mitophagy requires sensitive and reliable quantitative approaches. Since mitophagy is a rapidly progressing event and sub-microscopic in nature, live cell image-based detection tools with high spatial and temporal resolution is preferred over end-stage assays. We describe two approaches for measuring mitophagy in mammalian cells using stable cells expressing EGFP-LC3 – Mito-DsRed to mark early phase of mitophagy and Mitochondria-EGFP – LAMP1-RFP stable cells for late events of mitophagy. Both the assays showed good spatial and temporal resolution in wide-field, confocal and super-resolution microscopy with high-throughput adaptable capability. A limited compound screening allowed us to identify a few new mitophagy inducers. Compared to the current mitophagy tools, mito-Keima or mito-QC, the assay described here determines the direct delivery of mitochondrial components to the lysosome in real time mode with accurate quantification if monoclonal cells expressing a homogenous level of both probes are established. Since the assay described here employs real-time imaging approach in a high-throughput mode, the platform can be used both for siRNA screening or compound screening to identify key regulators of mitophagy at decisive stages.     

Natural occurrence of toxigenic fungi and mycotoxins in rice bran

Thirty four samples of rice bran, of which 9 were from raw (untreated) rice (RR) and 25 from parboiled rice (PbR) were collected from commercial rice mills in and around Madras and analysed for storage mycoflora and mycotoxins. Fungi of the Aspergillus flavus group were present in 29 of the 34 samples (8 from RR and 21 from PbR) in quantities ranging from <1–432 thousand propagules/g, though not always as the dominant mycoflora. Fungal numbers were usually higher in RR than in PbR samples.Five of the 9 RR samples and 6 of the 25 PbR samples were positive for aflatoxins. Among 29 isolates of A. flavus obtained from the bran samples, 16 isolates –6 from RR bran and 10 from PbR bran — were found to be toxigenic in vitro. Some isolates of A. candidus also seemed to produce aflatoxin and other fluorescent substances.     

Study on the vesicular-arbuscular mycorrhiza of three cultivars of potato (Solanum tuberosum L.)

Summary The establishment and development of vesicular-arbuscular mycorrhizal (VAM) fungi were studied in three cultivars of potato, which differed in susceptibility to Late blight, in a field experiment on a lateritic sandy-loam during two growing seasons (1980 and 1981). The cultivars SSC 1174 (highly resistant) and Kufri Jyoti (resistant) showed an earlier establishment and more rapid development of VAM fungi than up-to-date (highly susceptible). The first mycorrhizal infection in both SSC 1174 and Kufri Jyoti was observed after 12 days in 1980 and 8 days in 1981, whereas in up-to-date it was observed after 19 and 12 days respectively. The mycorrhizal infection increased with the age of the plants in all the three cultivars.     

Synthesis and x-ray structure of a Hg(II) complex with adenine N(1)-oxide. A model for mercury binding to DNA

The synthesis and crystal structure of the adenine N(1)-oxide complex with mercury(II) chloride, (C₅H₅N₅O)HgCl₂ are reported. Crystals of the coordination compound belong to the monoclinic system, space group P2₁/n with the following primary crystallographic data: a = 6.685(1) Å, b = 11.798(2) Å, c = 10.155(1) Å, β = 100.22(1)°, V = 906.04 ų, Z = 4. The structure was elucidated by conventional Patterson and Fourier methods and refined by the full matrix least-squares technique on the basis of 1977 observed reflections to an R value of 0.074. The basic unit of the structure is a dimer, with a centre of symmetry, consisting of two HgCl₂ moieties and two adenine N(1)-oxide ligands. A polymeric structure results from the bridging interactions of chloride ions. Adenine N(1)-oxide acts as a bidentate bridging ligand, coordinating through N(7) and O(1). The coordination geometry around the mercury ion is a distorted square pyramid with N(7) and three chlorines (two of which are centro-symmetrically related) forming the square plane and O(1) occupying the axial position. Hg also interacts indirectly with N(6) through a Cl

HN hydrogen bond. Principal intracomplex geometrical parameters are as follows: HgN(7) = 2.61(1) Å, HgO(1) = 2.55(1) Å, HgCl(1) = 2.330(3) Å, HgCl(2) = 2.318(3) Å, HgCl(2′) = 3.347(3) Å. The cis angles range from 77.5° to 107.9° and the two trans angles are 155.5° and 163.1°. The centro-symmetrically related bases overlap partially and pack at a distance of 3.2 Å. The glide-related bases are linked by a hydrogen bond, N(9)H

O(1) and are inclined to one another by 109.7°. The results are compared with those derived from spectroscopic and other physicochemical studies on metal interaction with adenine N(1)-oxide. Based on the present structural observations and earlier experimental results a possible mechanism is proposed for mercury interaction with DNA.     

Photoactivated disinfection (PAD) of dental root canal system – An ex-vivo study

AimTo investigate the efficacy of photo activated disinfection (PAD) in reducing colony-forming unit (CFU) counts of Enterococcus faecalis (E. faecalis) in infected dental root canals. The study compared the efficacy of PAD with conventional endodontic treatment (CET) and also a combination of CET along with PAD.Material and Methods53 maxillary incisors were taken for the study. Teeth were divided into 3 groups, CET (Group I) (n = 11), PAD (Group II) (n = 21), and a combination of CET and PAD (Group III) which consisted of (n = 21) samples, Group II and Group III were further divided into 2 subgroups, Group IIa, IIb and Group IIIa, IIIb. Strains of E. faecalis were inoculated in all the root canals. CET group samples were treated by chemo-mechanical preparation (CMP) alone, PAD samples were treated with laser alone at 2 different exposure time (4 min and 2 min). In the combination treatment, samples were treated initially by CET and then by PAD for a time period of 4 min and 2 min. Contents of the root canal were aspirated, diluted and plated in Tryptone Soya Broth (TSB) and plates were incubated for 24 h to observe the bacterial regrowth.ResultsShowed PAD used along with CMP reduced the bacterial load of E. faecalis by 99.5% at 4 min and 98.89% at 2 min.ConclusionPAD may be an adjunctive procedure to kill residual bacteria in the dental root canal systems after standard endodontic root canal preparation.