Santos, AGD, Klute W, Torode J, Bohm VPW, Cabrita E, Runsink J, Hoffmann RW.
1998.
Flexible molecules with defined shape. X. Synthesis and conformational study of 1,5-diaza-cis-decalin, SEP 1998. New Journal of Chemistry. 22:993-997., Number 9
Abstract
Gavel, OY, Bursakov SA, Calvete JJ, George GN, Moura JJ, Moura I.
1998.
ATP sulfurylases from sulfate-reducing bacteria of the genus Desulfovibrio. A novel metalloprotein containing cobalt and zinc, Nov 17. Biochemistry. 37:16225-32., Number 46
AbstractAdenosine triphosphate sulfurylase catalyzes the formation of adenosine 5'-phosphosulfate from adenosine triphosphate and sulfate. The enzyme plays a crucial role in sulfate activation, the key step for sulfate utilization, and has been purified from crude extracts of Desulfovibrio desulfuricans ATCC 27774 and Desulfovibrio gigas. Both proteins are homotrimers [141 kDa (3 x 47) for D. desulfuricans and 147 kDa (3 x 49) for D. gigas] and have been identified, for the first time, as metalloproteins containing cobalt and zinc. EXAFS reveals that either cobalt or zinc binds endogenously at presumably equivalent metal binding sites and is tetrahedrally coordinated to one nitrogen and three sulfur atoms. Furthermore, the electronic absorption spectra display charge-transfer bands at 335 and 370 nm consistent with sulfur coordination to cobalt, and as expected for a distorted tetrahedral cobalt geometry, d-d bands are observed at 625, 666, and 715 nm. This geometry is supported by the observation of high-spin Co2+ EPR signals at g approximately 6.5.
GROET, J, Ives {JH }, South {AP }, Baptista {PR }, Jones {TA }, Yaspo {ML }, Lehrach H, Potier {MC }, {Van Broeckhoven} C, Nizetic D.
1998.
Bacterial contig map of the 21q11 region associated with Alzheimer's disease and abnormal myelopoiesis in Down syndrome, jan. Genome Research. 8:385–398., Number 4: Cold Spring Harbor Laboratory Press
AbstractWe present a high-resolution bacterial contig map of 3.4 Mb of genomic DNA in human chromosome 21q11-q21, encompassing the region of elevated disomic homozygosity in Down Syndrome-associated abnormal myelopoiesis and leukemia, as well as the markers, which has shown a strong association with Alzheimer's Disease that has never been explained. The map contains 89 overlapping PACs, BACs, or cosmids in three contigs (850, 850, and 1500 kb) with two gaps (one of 140-210 kb and the second < 5 kb). To date, eight transcribed sequences derived by cDNA selection, exon trapping, and/or global EST sequencing have been positioned onto the map, and the only two genes so far mapped to this cytogenetic region, STCH and RIP140 have been precisely localized. This work converts a further 10% of chromosome 21q into a high-resolution bacterial contig map, which will be the physical basis for the long-range sequencing of this region. The map will also enable positional derivation of new transcribed sequences, as well as new polymorphic probes, that will help in elucidation of the role the genes in this region may play in abnormal myelopoiesis and leukemia associated with trisomy 21 and Alzheimer's Disease.
Flomen, {RH }, Vatcheva R, Gorman {PA }, Baptista {PMRV}, Groet J.
1998.
Construction and analysis of a sequence-ready map in 4q25: Rieger syndrome can be caused by haploinsufficiency of RIEG, but also by chromosome breaks approximate to 90 kb upstream of this gene, feb. Genomics. 47:409–413., Number 3: Elsevier
AbstractThe autosomal dominant disorder Rieger syndrome (RIEG) shows genetic heterogeneity and has a phenotype characterized by malformations of the anterior segment of the eye, failure of the periumbilical skin to involute, and dental hypoplasia. The main locus for RIEG was mapped to the 4q25-q27 chromosomal segment using a series of cytogenetic abnormalities as well as by genetic linkage to DNA markers. Recently, a bicoid-related homeobox transcription factor gene called RIEG has been cloned, characterized, and proven to cause the 4q25 linked RIEG. Its mode of action in the pathogenesis of RIEG was not conclusively proven, since most etiological mutations detected. In the RIEG sequence caused amino acid substitutions or splice changes in the homeodomain. Through FISH analysis of a 460-kb sequence-ready map (PAC contig) around RIEG that we report in this paper, we demonstrate that the 4q25 linked RIEG disorder can arise from the haploid, whole-gene deletion of RIEG, but also from a translocation break 90 kb upstream from the gene. The data provide conclusive evidence that physical or functional haploinsufficiency of RIEG is the pathogenic mechanism for Rieger syndrome. The map also defines restriction fragments bearing sequences with a potential key regulatory role in the control of homeobox gene expression.
Feio, MJ, Beech IB, Carepo M, Lopes JM, Cheung CW, Franco R, Guezennec J, Smith JR, Mitchell JI, Moura JJ, Lino AR.
1998.
Isolation and characterisation of a novel sulphate-reducing bacterium of the Desulfovibrio genus, Apr. Anaerobe. 4:117-30., Number 2
AbstractA novel sulphate-reducing bacterium (Ind 1) was isolated from a biofilm removed from a severely corroded carbon steel structure in a marine environment. Light microscopy observations revealed that cells were Gram-negative, rod shaped and very motile. Partial 16S rRNA gene sequencing and analysis of the fatty acid profile demonstrated a strong similarity between the new species and members from the Desulfovibrio genus. This was confirmed by the results obtained following purification and characterisation of the key proteins involved in the sulphate-reduction pathway. Several metal-containing proteins, such as two periplasmic proteins: hydrogenase and cytochrome c3, and two cytoplasmic proteins: ferredoxin and sulphite reductase, were isolated and purified. The latter proved to be of the desulfoviridin type which is typical of the Desulfovibrio genus. The study of the remaining proteins revealed a high degree of similarity with the homologous proteins isolated from Desulfovibrio gigas. However, the position of the strain within the phylogenetic tree clearly indicates that the bacterium is closely related to Desulfovibrio gabonensis, and these three strains form a separate cluster in the delta subdivision of the Proteobacteria. On the basis of the results obtained, it is suggested that Ind 1 belongs to a new species of the genus Desulfovibrio, and the name Desulfovibrio indonensis is proposed.
Bencini, A, Bernardo MA, Bianchi A, Ciampolini M, Fusi V, Nardi N, Parola AJ, Pina F, Valtancoli B.
1998.
Modulation of the ligational properties of a new cylindrical macrotricycle by coupling of photochemical- and pH-switching properties, 1998. Journal of the Chemical Society-Perkin Transactions 2. :413-418.
AbstractThe new cylindrical molecule L containing two tetraazamacrocyclic rings linked by two azobenzene pillars displays photoelastic properties, Light absorption at 366 nm gives rise to trans --> cis isomerization of the azobenzene moieties producing two isomers containing one or two cis-azobenzenes, respectively, The three trans-trans (E-E), trans-cis (E-Z) and cis-cis (Z-Z) isomers have been identified and characterized by H-1 NMR spectroscopy, allowing the dependence of their formation percentages with irradiation time to be determined, The sequence of photochemical reactions E-E --> E-Z --> Z-Z allows almost complete conversion of the E-E into the Z-Z isomer at 366 nm and 298 K, Both thermal (k = 1.75 x 10(-5) s(-1) at 313 K) and photo-induced (at 436 and 313 nm) back-isomerization reactions have been studied, The protonation constants of the three isomers in equimolar solutions of water-DMSO indicate a decreasing basicity in the order E-E > E-Z > Z-Z, in agreement with increasing electrostatic repulsion between the positive charges caused by a reduction in the separation between the protonation sites occurring upon Z --> E isomerization.
Pina, F, Melo MJ, Parola AJ, Maestri M, Balzani V.
1998.
pH-controlled photochromism of hydroxyflavylium ions, 1998. Chemistry-a European Journal. 4:2001-2007.
AbstractThe structural transformations and photochromic properties of the 7-hydroxyflavylium ion have been investigated by means of the pH jump technique and continuous and pulsed light excitation. The primary photoproduct of UV irradiation of the colorless trans-chalcone form, which is the predominant species at pH 4, is its colorless cis isomer, which rapidly disappears on a time scale of seconds through two competitive processes: i) back-reaction to yield the trans-chalcone form, and ii) formation of the colored flavylium ion and its conjugated quinoidal base. Over minutes or hours (depending on pH), the system reverts quantitatively to its original state. The rate constants and equilibrium constants of the various processes have been obtained and compared with those previously reported for the 4'-hydroxyflavylium and 4',7-dihydroxyflavylium ions. This comparison demonstrates the substituent effect on the rate and equilibrium constants; the effect on the rate constant of the cis-->trans thermal isomerization reaction is particularly strong. For the 7-hydroxyflavylium and 4',7-dihydroxyflavylium ions the pH of the solution plays the role of a tap for the color intensity generated by light excitation. This also means that this system can be viewed as a light-switchable pH indicator.