Glycerol-induced unraveling of the tight helical conformation of Escherichia coli type 1 fimbriae.

Glycerol was found to unravel the helical conformation of Escherichia coli type 1 fimbriae without appreciable depolymerization. The linearized fimbrial polymers have a diameter of 2 nm, react strongly with a monoclonal antibody directed at an inaccessible epitope on native fimbriae, and display greater mannose-binding activity and trypsin sensitivity than native fimbriae. Removal of glycerol by dialysis results in spontaneous reassembly of the linear polymers into structures morphologically, antigenically, and functionally indistinguishable from native fimbriae.     

Multiple mRNAs are generated from the chicken lysozyme gene

We have determined the DNA sequence of a 770 by Pst I fragment containing 450 nucleotides of the 5′ flanking region of the chicken lysozyme gene. S1-nuclease mapping was performed to localize the 5′ end of nuclear RNA containing lysozyme-specific sequences and of the mRNA. We present evidence that the 5′ noncoding region of the chicken lysozyme mRNA is heterogeneous in length. The 5′ termini of the different mRNAs map 29, 31 and 53 nucleotides upstream from their common initiation codon. The 5′ ends of lysozyme-specific nuclear RNAs map at positions similar to that of the mRNA. AT-rich regions and sequences similar to the E. coli RNA polymerase recognition sequence are found around 30 and 70 nucleotides upstream from each of these 5′ termini. The AT-rich regions differ, however, from the canonical Goldberg-Hogness box in that they do not contain the extremely conserved TATA sequence motif. Sequence comparison at the 5′ end of the lysozyme, conalbumin and ovalbumin genes reveals only one region of partial homology, 140 nucleotides upstream from the mRNA start sites.     

Arylesterase activity of paraoxonase 1 (PON1) on HDL3 and HDL2: Relationship with Q192R,C-108T,and L55M polymorphisms

BackgroundControversy exists regarding the role of the subfractions of high-density lipoproteins (HDL₂ and HDL₃) in cardiovascular disease. The functionality of these particles, and their protective role, is due in part to the paraoxonase 1 (PON1) presence in them. The polymorphisms rs662 (Q192R, A/G), rs854560 (L55 M, T/A), and rs705379 (C-108T) of the PON1 gene have been related to enzyme activity and, with the anti-oxidative capacity of the HDL. The objective was to determine the arylesterase PON1 activity in HDL₃ and HDL₂ and its relationship with the polymorphisms mentioned, in a young population.MethodsThe polymorphisms were determined through mini-sequencing (SnaPshot). The HDL subpopulations were separated via ionic precipitation, cholesterol was measured with enzymatic methods, and PON1 activity was measured through spectrophotometry.ResultsThe results show that the PON1 polymorphisms do not influence the cholesterol in the HDL. A variation between 40.02 and 43.9 mg/dL was in all the polymorphisms without significant differences. Additionally, PON1 activity in the HDL₃ subfractions was greater (62.83 ± 20 kU/L) than with HDL₂ (35.8 ± 20.8 kU/L) in the whole population and in all the polymorphisms (p < 0.001), and it was independent of the polymorphism and differential arylesterase activity in the Q192R polymorphism (QQ > QR > RR). Thus, 115.90 ± 30.7, 88.78 ± 21.3, 65.29 ± 10.2, respectively, for total HDL, with identical behavior for HDL₃ and HDL₂.ConclusionsPON1 polymorphisms do not influence the HDL_-c, and the PON activity is greater in the HDL₃ than in the HDL₂, independent of the polymorphism, but it is necessary to delve into the functionality of these findings in different populations.     

Coenzyme Q10 deficiency in mitochondrial DNA depletion syndromes

We evaluated coenzyme Q₁₀ (CoQ) levels in patients studied under suspicion of mitochondrial DNA depletion syndromes (MDS) (n = 39). CoQ levels were quantified by HPLC, and the percentage of mtDNA depletion by quantitative real-time PCR. A high percentage of MDS patients presented with CoQ deficiency as compared to other mitochondrial patients (Mann–Whitney-U test: p = 0.001). Our findings suggest that MDS are frequently associated with CoQ deficiency, as a possible secondary consequence of disease pathophysiology. Assessment of muscle CoQ status seems advisable in MDS patients since the possibility of CoQ supplementation may then be considered as a candidate therapy.     

Genome Analysis and Physiological Comparison of Alicycliphilus denitrificans Strains BC and K601T

The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601^T have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601^T is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601^T are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacterium that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601^T and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601^T. Genes involved in cyclohexanol degradation were only found in strain K601^T. Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far.     

Two silicone nontoxic fouling release coatings: Hydrosilation cured PDMS and CaCO3 filled,ethoxysiloxane cured RTV11

Two silicone coatings have been evaluated for barnacle adhesion. One coating is an unfilled hydrosilation cured polydimethylsiloxane (PDMS) network, while the other is a room temperature vulcanized (RTV), filled, ethoxysiloxane cured PDMS elastomer, RTV11^?. The adhesion strength of one species of barnacle, Balanus eburneus, to the hydrosilation coatings is in the range of 0.37–0.60 kg cm^‐2 while the corresponding range for RTV11 is 0.64–0.90 kg cm^‐2. The easier release of B. eburneus from the hydrosilation cured network compared to RTV11 is discussed in relationship to differences in bulk and surface properties. Preliminary results suggest bulk modulus may be the most important parameter in determining barnacle adhesion strength. In light or mechanical property analysis, a re‐evaluation of surface properties and chemical stability is presented.     

Levels of 5-methyltetrahydrofolate and ascorbic acid in cerebrospinal fluid are correlated: Implications for the accelerated degradation of folate by reactive oxygen species

Deficiency of 5-methyltetrahydrofolate (5-MTHF) in cerebrospinal fluid (CSF) is associated with a number of neurometabolic conditions including mitochondrial electron transport chain defects. Whilst failure of the active transport of 5-methyltetrahydrofolate (5-MTHF) into the CSF compartment has been proposed as a potential mechanism responsible for the 5-MTHF deficiency seen in mitochondrial disorders, it is becoming increasingly clear that other mechanisms are involved. Here, we have considered the role of oxidative stress as a contributing mechanism. Concerning, ascorbic acid (AA), we have established a CSF reference range (103–303 μM) and demonstrated a significant positive correlation between 5-MTHF and AA. Furthermore, CSF itself was also shown to convey antioxidant properties towards 5-MTHF. However, this protection could be overcome by the introduction of a hydroxyl radical generating system. Using a neuronal model system, inhibition of mitochondrial complex I, by 58%, was associated with a 23% increase in superoxide generation and a significantly increased loss of 5-MTHF from the extracellular medium. Addition of AA (150 μM) was able to prevent this increased 5-MTHF catabolism. We conclude that increased generation of reactive oxygen species and/or loss of CSF antioxidants are also factors to consider with regard to the development of a central 5-MTHF deficiency. Co-supplementation of AA together with appropriate folate replacement may be of therapeutic benefit.