STANDARDIZATION OF FRIABLE CALLUS DEVELOPMENT IN CATHARANTHUS ROSEUS (LINN.) G. DON

Objective: The objective of the study was to develop an effective hormonal combination for the maximum growth of callus and development of friable calli using the same medium with reduced concentration of agar.Methods: The percentage responses of five varied growth hormonal combinations and concentrations, supplemented with Murashige and Skoog (MS)medium were recorded. The effect of casein hydrolysate on callus induction was also studied. The nature of friable calli obtained from best responsive media fortified with 0.7% and 0.6% agar was observed.Results: The present study revealed that, three media viz., MS + 1.0 mg/L BAP + 1.0 mg/L NAA, MS + 1.5 mg/L 2,4-D + 1.0 mg/L Kin and MS + 1.5 mg/L 2,4-D + 0.5 mg/L BAP, as the best responsive media in the descending order. The effect of casein hydrolysate supplemented along with the above three media revealed MS + 1.0 mg/LBAP + 1.0 mg/L NAA + 1.0 gm/L casein hydrolysate as the best responsive media. Also, the above media supplemented with 0.6% agar was found to be the effective in terms of nature and amount of friable callus obtained.Conclusion: The results indicated MS + 1.0 mg/L BAP + 1.0 mg/L NAA + 1.0 gm/L casein hydrolysate + 0.6% agar (85% response) as the best media for the growth and development of both callus and friable callus.Â

Frustration and glassiness in spin models with cavity-mediated interactions

We show that the effective spin-spin interaction between three-level atoms confined in a multimode optical cavity is long-ranged and sign-changing, like the RKKY interaction; therefore, ensembles of such atoms subject to frozen-in positional randomness can realize spin systems having disordered and frustrated interactions. We argue that, whenever the atoms couple to sufficiently many cavity modes, the cavity-mediated interactions give rise to a spin glass. In addition, we show that the quantum dynamics of cavity-confined spin systems is that of a Bose-Hubbard model with strongly disordered hopping but no on-site disorder; this model exhibits a random-singlet glass phase, absent in conventional optical-lattice realizations. We briefly discuss experimental signatures of the realizable phases.Comment: 5 pages, 2 figure

Marine Fish Calendar. 11. Bombay

There are three major fish landing centres in Bombay, namely Sassoon Dock, Versova and New Ferry Wharf. Catch data from Sassoon Dock are made use of in the preparation of this marine fish calendar. Data used for this calendar are the annual and monthly averages of the catches of the three year period from 1983 to '85 for the three major gears

Extraction, purification and analysis of thermal stability of xylose isomerase

Thermostable enzymes are the enzymes which active even at high temperatures, such enzymes are industrially as well as biochemically very important. Xylose isomerase (EC 5.3.1.5) is one such enzyme with suitable commercial applications. It is heat stable and does not require expensive cofactors such as NAD or ATP for activity. The microorganisms producing this enzyme were isolated from hot water spring near ‘Surat’. The organisms were isolated and purified by using different screening methods. The isolated organisms were then subjected to optimum growth conditions for enzyme production. This enzyme was then assayed for its thermal stability at elevated temperatures by using DNSA

Analysis of protease activity of enzyme isolated from compost soil

Bacteria are very good source of enzymes as compared to animal or plant source and even synthetic enzymes. In the present investigation the protease activity has been analyzed. The source of enzyme i.e. protease producers were isolated from compost soil sample viz. collected from the Wanker farm field, Solapur. The protease producers were isolated, screened and grown on a suitable growth medium to obtain maximum production of enzyme. After production the crude enzyme is purified. The purified enzyme is analysed for its keratinolytic activity by using feathers

Atom-light crystallization of BECs in multimode cavities: Nonequilibrium classical and quantum phase transitions, emergent lattices, supersolidity, and frustration

The self-organization of a Bose-Einstein condensate in a transversely pumped optical cavity is a process akin to crystallization: when pumped by a laser of sufficient intensity, the coupled matter and light fields evolve, spontaneously, into a spatially modulated pattern, or crystal, whose lattice structure is dictated by the geometry of the cavity. In cavities having multiple degenerate modes, the quasi-continuum of possible lattice arrangements, and the continuous symmetry breaking associated with the adoption of a particular lattice arrangement, give rise to phenomena such as phonons, defects, and frustration, which have hitherto been unexplored in ultracold atomic settings involving neutral atoms. The present work develops a nonequilibrium field-theoretic approach to explore the self-organization of a BEC in a pumped, lossy optical cavity. We find that the transition is well described, in the regime of primary interest, by an effective equilibrium theory. At nonzero temperatures, the self-organization occurs via a fluctuation-driven first-order phase transition of the Brazovskii class; this transition persists to zero temperature, and crosses over into a quantum phase transition of a new universality class. We make further use of our field-theoretic description to investigate the role of nonequilibrium fluctuations on the self-organization transition, as well as to explore the nucleation of ordered-phase droplets, the nature and energetics of topological defects, supersolidity in the ordered phase, and the possibility of frustration controlled by the cavity geometry. In addition, we discuss the range of experimental parameters for which we expect the phenomena described here to be observable, along with possible schemes for detecting ordering and fluctuations via either atomic correlations or the correlations of the light emitted from the cavity.Comment: 34 pages, 13 figures; follow up to Nat. Phys. 5, 845 (2009

Approaching Zero-Temperature Metallic States in Mesoscopic Superconductor-Normal-Superconductor Arrays

Systems of superconducting islands placed on normal metal films offer tunable realizations of two-dimensional (2D) superconductivity; they can thus elucidate open questions regarding the nature of 2D superconductors and competing states. In particular, island systems have been predicted to exhibit zero-temperature metallic states. Although evidence exists for such metallic states in some 2D systems, their character is not well understood: the conventional theory of metals cannot explain them, and their properties are difficult to tune. Here, we characterize the superconducting transitions in mesoscopic island-array systems as a function of island thickness and spacing. We observe two transitions in the progression to superconductivity; both transition temperatures exhibit unexpectedly strong depression for widely spaced islands. These depressions are consistent with the system approaching zero-temperature metallic states. The nature of the transitions and the state between them is explained using a phenomenological model involving the stabilization of superconductivity on each island via a weak coupling to and feedback from its neighbors.Comment: 15 pages, 5 figure

Transglutaminase 2 Contributes to Apoptosis Induction in Jurkat T Cells by Modulating Ca(2+) Homeostasis via Cross-Linking RAP1GDS1

BACKGROUND: Transglutaminase 2 (TG2) is a protein cross-linking enzyme known to be associated with the in vivo apoptosis program of T cells. However, its role in the T cell apoptosis program was not investigated yet. RESULTS: Here we report that timed overexpression of both the wild type (wt) and the cross-linking mutant of TG2 induced apoptosis in Jurkat T cells, the wt being more effective. Part of TG2 colocalised with mitochondria. WtTG2-induced apoptosis was characterized by enhanced mitochondrial Ca(2+) uptake. Ca(2+)-activated wtTG2 cross-linked RAP1, GTP-GDP dissociation stimulator 1, an unusual guanine exchange factor acting on various small GTPases, to induce a yet uncharacterized signaling pathway that was able to promote the Ca(2+) release from the endoplasmic reticulum via both Ins3P and ryanodine sensitive receptors leading to a consequently enhanced mitochondrial Ca(2+)uptake. CONCLUSIONS: Our data indicate that TG2 might act as a Ca(2+) sensor to amplify endoplasmic reticulum-derived Ca(2+) signals to enhance mitochondria Ca(2+) uptake. Since enhanced mitochondrial Ca(2+) levels were previously shown to sensitize mitochondria for various apoptotic signals, our data demonstrate a novel mechanism through which TG2 can contribute to the induction of apoptosis in certain cell types. Since, as compared to knock out cells, physiological levels of TG2 affected Ca(2+) signals in mouse embryonic fibroblasts similar to Jurkat cells, our data might indicate a more general role of TG2 in the regulation of mitochondrial Ca(2+) homeostasis