Evidence of activity-specific, radial organization of mitotic chromosomes in Drosophila

The organization and the mechanisms of condensation of mitotic chromosomes remain unsolved despite many decades of efforts. The lack of resolution, tight compaction, and the absence of function-specific chromatin labels have been the key technical obstacles. The correlation between DNA sequence composition and its contribution to the chromosome-scale structure has been suggested before; it is unclear though if all DNA sequences equally participate in intra- or inter-chromatin or DNA-protein interactions that lead to formation of mitotic chromosomes and if their mitotic positions are reproduced radially. Using high-resolution fluorescence microscopy of live or minimally perturbed, fixed chromosomes in Drosophila embryonic cultures or tissues expressing MSL3-GFP fusion protein, we studied positioning of specific MSL3-binding sites. Actively transcribed, dosage compensated Drosophila genes are distributed along the euchromatic arm of the male X chromosome. Several novel features of mitotic chromosomes have been observed. MSL3-GFP is always found at the periphery of mitotic chromosomes, suggesting that active, dosage compensated genes are also found at the periphery of mitotic chromosomes. Furthermore, radial distribution of chromatin loci on mitotic chromosomes was found to be correlated with their functional activity as judged by core histone modifications. Histone modifications specific to active chromatin were found peripheral with respect to silent chromatin. MSL3-GFP-labeled chromatin loci become peripheral starting in late prophase. In early prophase, dosage compensated chromatin regions traverse the entire width of chromosomes. These findings suggest large-scale internal rearrangements within chromosomes during the prophase condensation step, arguing against consecutive coiling models. Our results suggest that the organization of mitotic chromosomes is reproducible not only longitudinally, as demonstrated by chromosome-specific banding patterns, but also radially. Specific MSL3-binding sites, the majority of which have been demonstrated earlier to be dosage compensated DNA sequences, located on the X chromosomes, and actively transcribed in interphase, are positioned at the periphery of mitotic chromosomes. This potentially describes a connection between the DNA/protein content of chromatin loci and their contribution to mitotic chromosome structure. Live high-resolution observations of consecutive condensation states in MSL3-GFP expressing cells could provide additional details regarding the condensation mechanisms.     

The impact of HLA-DRB1 genes on extra-articular disease manifestations in rheumatoid arthritis

The objective of this study was to examine HLA-DRB1 and HLA-DQB1 genotypes in patients with severe extra-articular rheumatoid arthritis (ExRA) and to compare them with the genotypes of rheumatoid arthritis (RA) patients without extra-articular manifestations. Patients with severe ExRA were recruited from a large research database of patients with RA, from two cohorts of prevalent RA cases, and from a regional multicenter early RA cohort. Cases with ExRA manifestations (n = 159) were classified according to predefined criteria. Controls (n = 178) with RA but no ExRA were selected from the same sources. Cases and controls were matched for duration of RA and for clinical center. PCR based HLA-DRB1 and HLA-DQB1 genotyping was performed using the Biotest SSP kit, with additional sequencing in order to distinguish DRB1*04 subtypes. Associations between alleles and disease phenotypes were tested using multiple simulations of random distributions of alleles. There was no difference in global distribution of HLA-DRB1 and HLA-DQB1 alleles between patients with ExRA and controls. DRB1*0401 (P = 0.003) and 0401/0401 homozygosity (P = 0.002) were more frequent in Felty's syndrome than in controls. The presence of two HLA-DRB1*04 alleles encoding the shared epitope (SE) was associated with ExRA (overall odds ratio 1.79, 95% confidence interval 1.04-3.08) and with rheumatoid vasculitis (odds ratio 2.44, 95% confidence interval 1.22-4.89). In this large sample of patients with ExRA, Felty's syndrome was the only manifestation that was clearly associated with HLA-DRB1*0401. Other ExRA manifestations were not associated with individual alleles but with DRB1*04 SE double dose genotypes. This confirms that SE genes contribute to RA disease severity and ExRA. Other genetic and environmental factors may have a more specific impact on individual ExRA manifestations.     

Properties of glutamate dehydrogenase from Beta vulgaris

Glutamate-NAD oxidoreductase, E.C. 1.4.1.3 (GDH), from seedlings of Beta vulgaris cv. Rota, Jahnsch Peragis Comp., was enzymatically characterized. This enzyme with molecular weight of 2.6 × 10⁵ has a pH optimum of around 8 for animation of α-KGA and around 9.5 for the desamination of glutamate. The apparent K_m for α-KGA is 6.7 × 10^?4M, for NH₃ 2.5 × 10^?3M, for NADH 3.2 × 10^?5M and for NAADPH 5.5 × 10^?4M. NAD¹ inhibits the reaction non-competitively when NADPH serves as substrate. The apparent K¹ is 4.5 × 10^?4M. The data are discussed on relation to the properties of GDH from other plant sources.     

Prostaglandin E (sulproston) is neither luteolytic nor luteotrophic during the estrous cycle in the pig

Prostaglandin E₂ (Sulproston, S) can induce parturotion and luteolysis during late pregnancy in the pig. We now tested whether Sulproston is able to interfere with the duration of the pig's estrous cycle. Sulproston was given i.m. in two injections (0.008 mg/kg each) at 12-hour-intervals to ten gilts day 10, to five gilts day 14 and to five gilts day 16 of the estrous cycle. Blood was collected shortly before and up to 48 hrs after the onset of treatment; further daily blood samples were taken from a day 0 (1st day of standing heat) to the end of the cycle. Sulproston-administration did not shorten or lenghten the duration of the estrous cycle, nor were plasma-progesterone levels altered when compared to controls. In a second study five gilts received the tenfold amount in plasma-progesterone (8.52 ± 2.8 SEM ng, treatment vs. 32.95 ± 1.86 SEM ng/ml, control) occurred on day 11, which had returned by day 16 to the level of controls (19.22 ± 6.28 ng/ml vs. 26.75 ± 2.10 SEM ng/ml, respectively). No alteration in cycle length occurred. Therefore the PGE₂-analogue Sulproston - though luteolytic in late pregnancy - is neither luteolytic nor luteotrophic during the estrous cycle of the pig.     

A Simple and Rapid Computer-assisted Technique for the Identification of some Selected Bacillus Species using Biochemical Tests

A computer-assisted probabilistic identification technique was developed to identify species of the genus Bacillus known to be potentially pathogenic and/or frequently found as contaminants in pharmaceutical preparations. An identification matrix on 18 species of the genus Bacillus was constructed. Twenty-four biochemical tests were used. The reaction profile of each species was quantified in probability terms and called up on a computer. The computer method was used on 30 test cultures. In each case, the most likely identification, according to the computer method, was the species to which the strain had already been assigned. In 29 of the 30 cases, the identification was with a probability level of one; in seven of these, however, more than one species tied for first choice. Only one strain was identified with a lower level of probability. The technique developed is comparatively easy to use and would seem to constitute a useful diagnostic tool within the pharmaceutical field.     

HATCHING GLANDS IN THE TELEOSTS, BRACHYDANIO RERIO. DANIO MALABARICUS, MOENKHAUSIA OLIGOLEPIS AND BARBUS SCHUBERTI

Many teleost embryos produce an enzyme within specialized glands, which facilitate hatching. The enzyme attacks the chorion which becomes so weak that it may be ruptured easily by a blow of the tail.
The embryos of Brachydanio rerio, Danio malabaricus, Moenkhausia oligolepis and Barbus schuberti show some morphological differences in the distribution of the hatching gland cells. More specificity can be found in the ultrastructure of hatching gland cells, which are loaded with enzyme granules prior to hatching. In all four species the nucleus is located near the basis of the cell. The hatching enzyme is contained within granules, which arise from the Golgi body.     

A new species of Centaurea (sect. Phalolepis, Compositae: Cardueae) from eastern Peloponnisos, Greece

A new species of Centaurea L. , Centaurea leonidia Kalpoutz. & Constantin. , from two localities west and south-west of the town of Leonidio in eastern Peloponnisos, Greece, is described and illustrated. It belongs to C . sect. Phalolepis , and taxonomically its closest relatives are C. heldreichii Halácsy , a very localized species from south-west Sterea Ellas (Greece) and, surprisingly, C. niederi Heldr., which belongs to sect. Acrolophus. The new species is currently known from two populations of less than 100 individuals each, growing on almost inaccessible cliffs close to the convent of Agios Nikolaos Sintzas (St. Nicolas of Sintza) and the slopes of Poundes summit. Several other Greek endemic species are found in the same areas. Centaurea leonidia is scientifically important as it belongs to a small group of taxa, which, although they are members of sect. Phalolepis , have close allies in sect. Acrolophus. The chromosome number of C. leonidia , 2 n  = 18, counted in root tips, is also reported and illustrated.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 375–383.     

A new species of Achillea (Asteraceae: Anthemideae) from south-east Peloponnisos, Greece

A new species of Achillea L., Achillea occulta Constantin. & Kalpoutz., from the summit area of Mount Koulochera in south-east Peloponnisos, Greece, is described and illustrated. It belongs to A . sect. Ptarmica and further, to a small group of taxa known under the illegitimate sectional name 'Anthemoideae'. In Greece, A. occulta has no close allies. The taxonomically related taxa, i.e. A. barrelieri (Ten.) Sch. Bip., A. mucronulata Bertol., A. oxyloba (DC.) Sch. Bip. and A. schurii Sch. Bip. are found in the Italian Peninsula, the Alps and the Carpathians. Phytogeographically, the finding of a species with such taxonomic connections in south-east Greece was unexpected. The new species grows in semi-shade, often hidden in suitable limestone rock hollows and the foot of rocks, together with several other Greek endemics. Its chromosome number of 2 n  = 18, counted in root tips, is also reported and illustrated.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 249–256.     

The effects of free-air CO2 enrichment and soil water availability on spatial and seasonal patterns of wheat root growth

Spring wheat [ Triticum aestivum (L). cv. Yecora Rojo] was grown from December 1992 to May 1993 under two atmospheric CO₂ concentrations, 550 μmol mol^–1 for high-CO₂ plots, and 370 μmol mol^–1 for control plots, using a Free-Air CO₂ Enrichment (FACE) apparatus. In addition to the two levels of atmospheric CO₂, there were ample and limiting levels of water supply through a subsurface trip irrigation system in a strip, split-plot design. In order to examine the temporal and spatial root distribution, root cores were extracted at six growth stages during the season at in-row and inter-row positions using a soil core device (86 mm ID, 1.0 m length). Such information would help determine whether and to what extent root morphology is changed by alteration of two important factors, atmospheric CO₂ and soil water, in this agricultural ecosystem. Wheat root growth increased under elevated CO₂ conditions during all observed developmental stages. A maximum of 37% increase in total root dry mass in the FACE vs. Control plots was observed during the period of stem elongation. Greater root growth rates were calculated due to CO₂ enhancement until anthesis. During the early vegetative growth, root dry mass of the inter-row space was significantly higher for FACE than for Control treatments suggesting that elevated CO₂ promoted the production of first-order lateral roots per main axis. Then, during the reproductive period of growth, more branching of lateral roots in the FACE treatment occurred due to water stress. Significant higher root dry mass was measured in the inter-row space of the FACE plots where soil water supply was limiting. These sequential responses in root growth and morphology to elevated CO₂ and reduced soil water supports the hypothesis that plants grown in a high-CO₂ environment may better compensate soil-water-stress conditions.