Prokaryotic Community Characterization in a Mesothermic and Water- Flooded Oil Reservoir in Colombia

The prokaryotic community at the “La Cira-Infantas” oil field, located in Colombia's Middle Magdalena Valley Basin, was characterized using 16S rRNA gene sequence analysis. This characterization is a first-step in assessing the dynamics of microbial degradation and defining strategies that may increase oil recovery and quality at the site. Two 16S rRNA gene libraries were generated from the total community DNA extracted from production water using both Eubacterial and Archaea universal primers. Sequence analysis of the libraries indicated that a large percentage of Eubacteria clones were affiliated with class α-, β- and δ-Proteobacteria, Clostridia and Bacteroidetes. Archaea clones were dominated by Methanobacteria and Methanococci. Annotations at these generic levels indicate that the prokaryotic community has the following metabolic capacities: i) reduction of sulfur-compounds and fermentation, ii) nitrate reduction and sulfide oxidation, iii) decomposition of aromatic compounds, and iv) methane production. These results are discussed in the context of the importance of the characterized metabolic capacities for oil biodegradation in the mesothermic and water-flooded environment of this reservoir.     

Chemical composition, seasonal variation, and biosynthetic considerations of essential oils from Baccharis microdonta and B. elaeagnoides (Asteraceae)

The chemical composition and seasonal variation throughout one year of the essential oils from leaves of Baccharis microdonta and B. elaeagnoides, collected in Campos do Jordão, SP, were investigated. The composition of the latter species has been described for the first time. By GC (RI) and GC/MS analysis, 43 compounds were identified, and a predominance of oxygenated sesquiterpene derivatives was found in both species. The main components of the B. microdonta oils were elemol ( 31 ; 11.7–30.6%), spathulenol ( 34 ; 4.7–9.1%), β‐caryophyllene ( 19 ; 3.7–6.2%), and germacrene D ( 24 ; 2.9–12.2%), and those of the B. elaeagnoides oils were 34 (10.1–21.5%), viridiflorol ( 35 ; 3.6–18.4%), 24 (0.9–13.8%), and 19 (3.5–9.4%). The identified compounds were grouped according to their respective C‐skeletons, and the percentages of occurrence of the C‐skeletons in the essential oils of leaves collected in the four seasons allowed identifying the preferential accumulation of different types of C‐skeletons as well as the seasonal variation of the biosynthetic routes over the studied period.     

ATP-dependent enzyme activating hormone binding of estradiol receptor

Mouse uterus estradiol receptor undergoes a inactivation-reactivation process “in vitro”. The specific estrogen binding activity inactivated by nuclei, apparently through a dephosphorylation process (1,2,3), is reactivated by an ATP-dependent process. The enzyme reactivating the receptor has been purified from calf uterus cytosol. It shows high affinity for the inactive receptor (K_m of ～ 0.3 × 10^?9 mol of 17β-estradiol binding sites/l); it is simulated by MgCl₂ and CaCl₂. Present and previous results suggest that in cytoplasm of intact cells a phosphorylation process makes the receptor able to bind hormone and in nuclei dephosphorylation of receptor causes loss of hormone binding activity.     

Reporter substrates for assessing the activity of the hepatitis C virus NS3-4A serine protease in living cells

We describe a versatile system for monitoring the activity of the NS3-4A serine protease of the hepatitis C virus (HCV) in mammalian cells. The system relies on coexpression of the protease and of an artificial substrate containing a reporter domain and an intracellular targeting sequence separated by a NS3-4A-specific cleavage site. We constructed two different substrates suitable for different applications. The first substrate secretory alkaline phosphatase-1 (SEAP-1) harbors the NS3-4A cleavage site inserted between the SEAP and a membrane anchor featuring an endoplasmic reticulum retention sequence. The arrangement of this substrate is such that SEAP is secreted in the extracellular medium depending on the NS3 protease activity. We show that SEAP-1 can be used to evaluate the activity of NS3-4A inhibitors in living cells. In the second substrate (CD8-1), SEAP is replaced by the extracellular domain of the lymphocyte surface antigen CD8 alpha. The arrangement of this substrate is such that the CD8 alpha domain is transported to the cell surface upon NS3-4Ap cleavage and remains associated with the plasma membrane as an integral membrane protein. We show that CD8-1 can be used for selecting cells capable of supporting HCV replication.     

Control of megakaryocyte expansion and bone marrow fibrosis by lysyl oxidase

Lysyl oxidase (LOX), a matrix cross-linking protein, is known to be selectively expressed and to enhance a fibrotic phenotype. A recent study of ours showed that LOX oxidizes the PDGF receptor-β (PDGFR-β), leading to amplified downstream signaling. Here, we examined the expression and functions of LOX in megakaryocytes (MKs), the platelet precursors. Cells committed to the MK lineage undergo mitotic proliferation to yield diploid cells, followed by endomitosis and acquisition of polyploidy. Intriguingly, LOX expression is detected in diploid-tetraploid MKs, but scarce in polyploid MKs. PDGFR-BB is an inducer of mitotic proliferation in MKs. LOX inhibition with β-aminopropionitrile reduces PDGFR-BB binding to cells and downstream signaling, as well as its proliferative effect on the MK lineage. Inhibition of LOX activity has no influence on MK polyploidy. We next rationalized that, in a system with an abundance of low ploidy MKs, LOX could be highly expressed and with functional significance. Thus, we resorted to GATA-1(low) mice, where there is an increase in low ploidy MKs, augmented levels of PDGF-BB, and an extensive matrix of fibers. MKs from these mice display high expression of LOX, compared with control mice. Importantly, treatment of GATA-1(low) mice with β-aminopropionitrile significantly improves the bone marrow fibrotic phenotype, and MK number in the spleen. Thus, our in vitro and in vivo data support a novel role for LOX in regulating MK expansion by PDGF-BB and suggest LOX as a new potential therapeutic target for myelofibrosis.     

Spiralizations and tropisms in Arabidopsis roots.

When Arabidopsis seedlings are grown on a hard-agar plate, their primary roots show characteristic spiralling movements, apparent as waves, coils and torsions, together with a slanting toward the right-hand side. All these movements are believed to be the result of three different processes acting on the roots: circumnutation, positive gravitropism and negative thigmotropism. The basic movement of the roots is described as that of a growing right-handed helix, which, because of the root tip hitting the agar plate, is continuously switched from the right-hand to the left-hand of the growth direction, and vice versa. This movement also produces a slanting root-growth direction toward the right-hand because of the incomplete waves made by the right-handed root to the left-hand. By contrast, the torsions seen in the coils and waves are interpreted as artefacts that form as an adaptation of the three-dimensional root helix to the flat two-dimensional agar surface.     

Kinematics of running at different slopes and speeds

The aim of this study was to verify the influence of the combination of different running speeds and slopes based on main kinematic parameters in both groups of elite (RE) and amateur (RA) marathon runners. All subjects performed various tests on a treadmill at 0, 2, and 7% slopes at different speeds: 3.89, 4.17, 4.44, 4.72, and 5.00 m·s. A high speed digital camera, 210 Hz, has been used to record; Dartfish 5.5Pro has been used to perform a 2D video analysis. Step length (SL), step frequency (SF), flight time (FT), and contact time (CT) were determined and used for comparison. SL, SF, and FT parameters increased, and CT parameter decreased as speed increased. As slopes increased, SL and FT decreased and SF increased in both groups and only CT decreased in RE, whereas in RA, it increased. Data were fitted to the linear regression line (R > 0.95). The 2 groups were significantly different (p < 0.05) in FT, SL, and SF at all speeds in level running. A significant difference between the 2 groups was found in FT at 2 and 7% slopes at all speeds (p < 0.05). Percentage alterations in all variables were greater in the RA group. In conclusion, the choice of optimum SL and SF, through efficient running can be maintained, is influenced not only by speed but also by slopes. Elite runners perform more efficiently than amateur runners who have less experience.