458 research outputs found

    Prospecting for scarabid specific Bacillus thuringiensis crystal toxin cry8 gene in sugarcane ecosystem of Tamil Nadu, India

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    In the present study, we report the occurrence of cry8 positive isolates of Bacillus thuringiensis (Bt) in selected white grub, Holotrichia serrata F. (Coleoptera: Scarabaeidae), endemic soils of sugarcane ecosystem and other places in Tamil Nadu. Out of the 66 soil samples collected and screened for white grub specific Bt, 74 isolates of the bacterium, all containing only spherical crystal toxin, were identified. PCR screening of these isolates with cry8 gene universal primer revealed six isolates to be positive. Further, the amplicon of a 370 bp band, amplified with another set of degenerate primer designed based on the conserved sequence of cry8 genes, was sequenced from four isolates. Multiple sequence alignment revealed the gene sequences to be the same for all the isolates. The present report of the availability of cry8 positive Bt isolates opens the avenue for controlling white grubs through transgenic research

    Origin of germ cells and formation of new primary follicles in adult human ovaries

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    Recent reports indicate that functional mouse oocytes and sperm can be derived in vitro from somatic cell lines. We hypothesize that in adult human ovaries, mesenchymal cells in the tunica albuginea (TA) are bipotent progenitors with a commitment for both primitive granulosa and germ cells. We investigated ovaries of twelve adult women (mean age 32.8 ± 4.1 SD, range 27–38 years) by single, double, and triple color immunohistochemistry. We show that cytokeratin (CK)+ mesenchymal cells in ovarian TA differentiate into surface epithelium (SE) cells by a mesenchymal-epithelial transition. Segments of SE directly associated with ovarian cortex are overgrown by TA, forming solid epithelial cords, which fragment into small (20 micron) epithelial nests descending into the lower ovarian cortex, before assembling with zona pellucida (ZP)+ oocytes. Germ cells can originate from SE cells which cover the TA. Small (10 micron) germ-like cells showing PS1 meiotically expressed oocyte carbohydrate protein are derived from SE cells via asymmetric division. They show nuclear MAPK immunoexpression, subsequently divide symmetrically, and enter adjacent cortical vessels. During vascular transport, the putative germ cells increase to oocyte size, and are picked-up by epithelial nests associated with the vessels. During follicle formation, extensions of granulosa cells enter the oocyte cytoplasm, forming a single paranuclear CK+ Balbiani body supplying all the mitochondria of the oocyte. In the ovarian medulla, occasional vessels show an accumulation of ZP+ oocytes (25–30 microns) or their remnants, suggesting that some oocytes degenerate. In contrast to males, adult human female gonads do not preserve germline type stem cells. This study expands our previous observations on the formation of germ cells in adult human ovaries. Differentiation of primitive granulosa and germ cells from the bipotent mesenchymal cell precursors of TA in adult human ovaries represents a most sophisticated adaptive mechanism created during the evolution of female reproduction. Our data indicate that the pool of primary follicles in adult human ovaries does not represent a static but a dynamic population of differentiating and regressing structures. An essential mission of such follicular turnover might be elimination of spontaneous or environmentally induced genetic alterations of oocytes in resting primary follicles

    Magnetism in C<SUB>60</SUB> films induced by proton irradiation

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    It is shown that polycrystalline fullerene thin films on hydrogen-passivated Si(111) substrates irradiated by 2 MeV protons display ferromagneticlike behavior at 5 K. At 300 K, both the pristine and the irradiated film show diamagnetic behavior. Magnetization data in the temperature range of 2-300 K in 1 T applied field, for the irradiated film show much stronger temperature dependence compared to the pristine film. Possible origins of ferromagneticlike signals in the irradiated films are discussed

    Hexanitrohexaazaisowurtzitane or CL-20 in India: Synthesis and Characterisation

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    Hexanitrohexaazaisowurtzitane (HNIW) more commonly called CL-20, the highest density and the most powerful real world explosive, has been made with very high yield and a high product purity. CL-20 is thoroughly characterised by spectral data (IR, NMR and mass) along with electron spectroscopy for chemical analysis (ESCA) and X-ray diffractogram. Furthermore, small-scale sensitivity tests have also been carried out

    Methyl 3-(4-chloro­phen­yl)-1-methyl-1,2,3,3a,4,11c-hexa­hydro­benzo[f]chromeno[4,3-b]pyrrole-3a-carboxyl­ate

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    In the title compound, C24H22ClNO3, the dihedral angle between the naphthalene ring system and the chloro­phenyl ring is 67.44 (4)°. The pyrrolidine and dihydro­pyran rings exhibit envelope and half chair conformations, respectively. In the crystal structure, weak C—H⋯π inter­actions are observed

    Methyl 4-(4-chloro­phen­yl)-1,2,3,3a,4,4a,5,12c-octa­hydro­benzo[f]chromeno[3,4-b]pyrrolizine-4a-carboxyl­ate

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    There are two mol­ecules in the asymmetric unit of the title compound, C26H24ClNO3. The dihedral angles between the naphthalene ring system and the chloro­phenyl substituent are 58.76 (9) and 51.59 (8)° in the two mol­ecules. In the pyrrolizine ring system, both the pyrrolidine rings adopt envelope conformations and the dihydro­pyran rings adopt half-chair conformations. In the pyrrolizine ring system of one of the mol­ecules, one of the C atoms is disordered over two positions with site occupancies of 0.69 (2) and 0.31 (2). The crystal packing is stabilized by weak intra­molecular C—H⋯O inter­actions and the crystal packing is stabilized by weak C—H⋯π inter­actions

    Magnetization and Neutron Diffraction Studies on Dy5Si2Ge2

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    The compound Dy5Si2Ge2 crystallizes in an orthorhombic structure (Sm5Ge4 type, space group Pnma). Magnetization measurements performed in the temperature range of 2-300 K in applied fields up to 7 T reveal that this compound orders antiferromagnetically at 56 K (TN) but with a positive paramagnetic Curie temperature θP. Magnetization-field isotherms, obtained at 5 K and 20 K, display a field-induced antiferromagnetic to ferromagnetic transition. the magnetization approaches saturation in a field of 6 T with a moment value of ~8μBDy3+. Neutron diffraction measurements, carried out at 9.2 K, suggest that Dy moments arrange spirally along an axis giving rise to a canted antiferromagnetic structure. the analysis of neutron diffraction data yields an ordered state magnetic moment of 7.63μB per Dy3+ ion. © 2005 American Institute of Physics

    (3S,4R)-4-(4-Fluoro­phen­yl)-3-(hydroxy­meth­yl)piperidinium chloride1

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    The title compound, C12H17FNO+·Cl−, is a degradation impurity of paroxetine hydro­chloride hemihydrate (PAXIL), an anti­depressant belonging to the group of drugs called selective serotonin reuptake inhibitors (SSRIs). Similar to the paroxetine hydro­chloride salt with protonation having taken place on the basic piperidine ring, the degradation impurity also exists as the hydro­chloride salt. The cyclic six-membered piperidinium ring adopts a chair conformation with the hydroxy­methyl and 4-fluoro­phenyl groups in the equatorial positions. The ions form a tape along the b axis through charge-assisted N+—H⋯Cl− hydrogen bonds; these tapes are connected by O—H⋯Cl− hydrogen bonds along the a axis

    Magnetic Ordering in the Rare Earth Intermetallic Compound Tb₂Ti₃Ge₄: Magnetization and Neutron Diffraction Studies

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    Magnetization and neutron diffraction studies on a polycrystalline Tb2Ti3Ge4 sample (orthorhombic Sm5Ge4-type structure, space group Pnma, No. 62) have been carried out. This compound is found to order antiferromagnetically at ~18 K (TN). The magnetization (M) versus field (H) isotherms obtained at 2, 3, 5, and 10 K indicate a field-induced antiferromagnetic to ferromagnetic transition in fields of the order of 0.5 T. The saturation magnetization value at 2.5 K (M extrapolated to 1/H--\u3e0) is only ~5.6µB/Tb3+, suggesting the possible presence of crystal field effects with or without a persisting antiferromagnetic component. Neutron powder diffraction data at 10 K confirm the existence of a magnetic long range order. Modeling of the magnetic scattering reveals a complex and incommensurate antiferromagnetic spin structure below TN

    Methyl 4-(4-chloro­phen­yl)-3,3a,4,4a,5,12c-hexa­hydro-2-thia­naphtho­[1′,2′:3,2]furo[5,4-b]pyrrolizine-4a-carboxyl­ate

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    In the title compound, C25H22ClNO3S, both the pyrrolidinyl and thia­zolyl rings adopt envelope conformations whereas the dihydro­pyran ring adopts a half-chair conformation. The chloro­phenyl and naphthalenyl ring systems are oriented at a dihedral angle of 59.7 (1)°. The crystal packing is stabilized by an intra­molecular C—H⋯N hydrogen bond and weak inter­molecular C—H⋯π inter­actions
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