Structural and magnetic studies of Schiff base complexes of nickel(ii) nitrite: change in crystalline state, ligand rearrangement and a very rare μ-nitrito-1κO:2κN:3κO′ bridging mode

Four new nickel(II) complexes, [Ni2L2(NO2)2]·CH2Cl2·C2H5OH, 2H2O (1), [Ni2L2(DMF)2(m-NO2)]ClO4·DMF (2a), [Ni2L2(DMF)2(m-NO2)]ClO4 (2b) and [Ni3L¢2(m3-NO2)2(CH2Cl2)]n·1.5H2O (3) where HL = 2-[(3-amino-propylimino)-methyl]-phenol, H2L¢ = 2-({3-[(2-hydroxy-benzylidene)-amino]-propylimino}-methyl)-phenol and DMF = N,N-dimethylformamide, have been synthesized starting with the precursor complex [NiL2]·2H2O, nickel(II) perchlorate and sodium nitrite and characterized structurally and magnetically. The structural analyses reveal that in all the complexes, NiII ions possess a distorted octahedral geometry. Complex 1 is a dinuclear di-m2-phenoxo bridged species in which nitrite ion acts as chelating co-ligand. Complexes 2a and 2b also consist of dinuclear entities, but in these two compounds a cis-(m-nitrito-1kO:2kN) bridge is present in addition to the di-m2-phenoxo bridge. The molecular structures of 2a and 2b are equivalent; they differ only in that 2a contains an additional solvated DMF molecule. Complex 3 is formed by ligand rearrangement and is a one-dimensional polymer in which double phenoxo as well as m-nitrito-1kO:2kN bridged trinuclear units are linked through a very rare m3-nitrito-1kO:2kN:3kO¢ bridge. Analysis of variable-temperature magnetic susceptibility data indicates that there is a global weak antiferromagnetic interaction between the nickel(II) ions in four complexes, with exchange parameters J of -5.26, -11.45, -10.66 and -5.99 cm-1 for 1, 2a, 2b and 3, respectively

Untangling membrane rearrangement in the Nidovirales

All known positive sense single-stranded RNA viruses induce host cell membrane rearrangement for purposes of aiding viral genome replication and transcription. Members of the Nidovirales order are no exception, inducing intricate regions of double membrane vesicles and convoluted membranes crucial for the production of viral progeny. Although these structures have been well studied for some members of this order, much remains unclear regarding the biogenesis of these rearranged membranes. Here, we discuss what is known about these structures and their formation, compare some of the driving viral proteins behind this process across the nidovirus order, and examine possible routes of mechanism by which membrane rearrangement may occur.

Azide monoliths as convenient flow reactors for efficient Curtius rearrangement reactions

The preparation and use of an azide-containing monolithic reactor is described for use in a flow chemistry device and in particular for conducting Curtius rearrangement reactions via acid chloride inputs.

Invasion of epithelial mammalian cells by Paracoccidioides brasiliensis leads to cytoskeletal rearrangement and apoptosis of the host cell

Paracoccidioides brasiliensis (Pb) yeast cells can enter mammalian cells and probably manipulate the host cell environment to favor their own growth and survival. We studied the uptake of strain Pb 18 into A549 lung and Vero epithelial cells, with an emphasis on the repercussions in the cytoskeleton and the apoptosis of host cells. Cytoskeleton components of the host cells, such as actin and tubulin, were involved in the P. brasiliensis invasion process. Cytochalasin D and colchicine treatment substantially reduced invasion, indicating the functional participation of microfilaments (MFs) and microtubules (MTs) in this mechanism. Cytokeratin could also play a role in the P. brasiliensis interaction with the host. Gp43 was recognized by anti-actin and anti-cytokeratin antibodies, but not by anti-tubulin. The apoptosis induced by this fungus in infected epithelial cells was demonstrated by various techniques: TUNEL, DNA fragmentation and Bak and Bcl-2 immunocytochemical expression. DNA fragmentation was observed in infected cells but not in uninfected ones, by both TUNEL and gel electrophoresis methods. Moreover, Bcl-2 and Bak did not show any differences until 24 h after infection of cells, suggesting a competitive mechanism that allows persistence of infection. Overexpression of Bak was observed after 48 h, indicating the loss of competition between death and survival signals. In conclusion, the mechanisms of invasion of host cells, persistence within them, and the subsequent induction of apoptosis of such cells may explain the efficient dissemination of P. brasiliensis. (C) 2004 Published by Elsevier SAS.

Preparation of different basic Si-MCM-41 catalysts and application in the Knoevenagel and Claisen-Schmidt condensation reactions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Autosomal rearrangement in Gryllus assimilis Fabricius, 1775 (Orthoptera, Gryllidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Complex cytogenetic rearrangement in a case of unicameral bone cyst

Cytogenetic analysis of a unicameral bone cyst surgically resected in an 11-year-old boy revealed a highly complex clonal structural rearrangement involving chromosomes 4, 6, 8, 16, 21, and both 12. These findings reinforce the need for further studies on unicameral bone cysts to verify the frequency and to understand the significance of chromosome anomalies in this type of lesion.

Identification of duplicated and stress-inducible Aox2b gene co-expressed with Aox1 in species of the Medicago genus reveals a regulation linked to gene rearrangement in leguminous genomes

In flowering plants, alternative oxidase (Aox) is encoded by 3-5 genes distributed in 2 subfamilies (Aox1 and Aox2). In several species only Aox1 is reported as a stress-responsive gene, but in the leguminous Vigna unguiculata Aox2b is also induced by stress. In this work we investigated the Aox genes from two leguminous species of the Medicago genus (Medicago sativa and Medicago truncatula) which present one Aox1, one Aox2a and an Aox2b duplication (named here Aox2b1 and Aox2b2). Expression analyses by semi-quantitative RT-PCR in M. sativa revealed that Aox1, Aox2b1 and Aox2b2 transcripts increased during seed germination. Similar analyses in leaves and roots under different treatments (SA, PEG, H2O2 and cysteine) revealed that these genes are also induced by stress, but with peculiar spatio-temporal differences. Aox1 and Aox2b1 showed basal levels of expression under control conditions and were induced by stress in leaves and roots. Aox2b2 presented a dual behavior, i.e., it was expressed only under stress conditions in leaves, and showed basal expression levels in roots that were induced by stress. Moreover, Aox2a was expressed at higher levels in leaves and during seed germination than in roots and appeared to be not responsive to stress. The Aox expression profiles obtained from a M. truncatula microarray dataset also revealed a stress-induced co-expression of Aox1, Aox2b1 and Aox2b2 in leaves and roots. These results reinforce the stress-inducible co-expression of Aox1/Aox2b in some leguminous plants. Comparative genomic analysis indicates that this regulation is linked to Aox1/Aox2b proximity in the genome as a result of the gene rearrangement that occurred in some leguminous plants during evolution. The differential expression of Aox2b1/2b2 suggests that a second gene has been originated by recent gene duplication with neofunctionalization. © 2013 Elsevier GmbH. All rights reserved.

Systematic and historical biogeography of the Bryconidae (Ostariophysi: Characiformes) suggesting a new rearrangement of its genera and an old origin of Mesoamerican ichthyofauna

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Total synthesis of (-)-indolizidine 167B via an unusual Wolff rearrangement from an alpha,beta-unsaturated diazoketone

A concise synthesis of the (-)-indolizidine alkaloid 167B and two formal syntheses of (-)-indolizidine 209D and (-)-coniceine are described in just three steps from an alpha,beta-unsaturated diazoketone, via an unusual photochemical Wolff rearrangement. Preparation of the unsaturated diazoketone is straightforward from N-Cbz-prolinal and a 3-diazo-2-oxopropylphosphonate, employing a Horner-Wadsworth-Emmons reaction. The strategy should be feasible and easily adaptable to the synthesis of other indolizidine alkaloids and analogues. (C) 2011 Elsevier Ltd. All rights reserved.

Saethre-Chotzen phenotype with learning disability and hyper IgE phenotype in a patient due to complex chromosomal rearrangement involving chromosomes 3 and 7

The authors describe on a Brazilian girl with coronal synostosis, facial asymmetry, ptosis, brachydactyly, significant learning difficulties, recurrent scalp infections with marked hair loss, and elevated serum immunoglobulin E. Standard lymphocyte karyotype showed a small additional segment in 7p21[46,XX,add(7)(p21)]. Deletion of the TWIST1 gene, detected by Multiplex Ligation Probe-dependent Amplification (MPLA) and array-CGH, was consistent with phenotype of SaethreChotzen syndrome. Array CGH also showed deletion of four other genes at 7p21.1 (SNX13, PRPS1L1, HD9C9, and FERD3L) and the deletion of six genes (CACNA2D2, C3orf18, HEMK1, CISH, MAPKAPK3, and DOCK3) at 3p21.31. Our case reinforces FERD3L as candidate gene for intellectual disability and suggested that genes located in 3p21.3 can be related to hyper IgE phenotype. (C) 2012 Wiley Periodicals, Inc.