Broad-spectrum antioxidant peptides derived from His residue-containing sequences present in human paraoxonase 1

Hydroxyl or peroxyl radicals and hypochlorous acid (HOCl) are known to cause the oxidation of lipoproteins. Here, we examined Cu²⁺-binding property of paraoxonase 1 (PON1), and antioxidant actions of peptides, resembling His residue-containing sequences in PON1, against oxidations by Cu²⁺, peroxyl radicals or HOCl. When Cu²⁺-binding property of PON1 was examined spectrophotometrically, the maximal Cu²⁺ binding was achieved at 1:1 molar ratio of PON1: Cu²⁺. Additionally, Cu²⁺-catalyzed oxidative inactivation of PON1 was prevented by Ca²⁺-depleted PON1 at 1:1 ratio, but not diethylpyrocarbonate (DEPC)-modified PON1, suggesting the participation of His residue in Cu²⁺-binding. When His-containing peptides were examined for antioxidant actions, those with either His residue at N-terminal position 2 or 3, or His-Pro sequence at C-terminal remarkably prevented Cu²⁺-mediated low density lipoprotein (LDL) oxidation and PON1 inactivation. Especially, FHKALY, FHKY or NHP efficiently prevented Cu²⁺-induced LDL oxidation (24 h), indicating a tight binding of Cu²⁺ by peptides. In support of this, the peptide/Cu²⁺ complexes exhibited a superoxide-scavenging activity. Separately, in oxidations by 2,2'-azobis-2-amidinopropane hydrochloride or HOCl, the presence of Tyrosine (Tyr) or Cysteine (Cys) residue markedly enhanced antioxidant action of His-containing peptides. These results indicate that His-containing peptides with Tys or Cys residues correspond to broad spectrum antioxidants in oxidation models employing Cu²⁺, 2,2'-azobis-2-amidinopropane hydrochloride (AAPH) or HOCl.     

Comparison of the Respiratory Metabolism of Plantago lanceolata L. and Plantago major L.

Bryce, J. H. and ap Rees, T. 1985. Comparison of the respiratorymetabolism of Plantago lanceolata L. and Plantago major L.—J.exp. Bot. 36 1559–1565. The aim of this work was to discover if the respiratory metabolismof the roots of Plantago lanceolata L. differed from that ofthe roots of Plantago major L. Measurements of oxygen uptakeand dry weight of excised root systems during growth of seedlingsprovided evidence that the two species differed in the amountof respiration needed to support a given increase in dry weight.Excised root systems were given a 6-h pulse in [U-¹⁴C]sucrosefollowed by a 16.5-h chase in sucrose. The detailed distributionof ¹⁴C amongst the major components of the roots at the endof the pulse and the chase revealed no significant differencebetween the two species. Patterns of ¹⁴CO₂ production from [1-¹⁴C],[2-¹⁴C], [3,4-¹⁴C], and [6-¹⁴C]glucose of excised root systemsfrom plants of three ages were similar for the two species.It is suggested that there is no conclusive evidence for anysignificant inherent difference in the respiratory metabolismof the roots of the two species. Key words: ¹⁴C sugar metabolism, respiration, roots, Plantago     

A restriction map of IncFIV plasmid R124

A physical and genetic map of the 125.7-kb IncFIV plasmid R124 was constructed using the restriction enzymes Sal1 and EcoR1. Two discrete regions involved in plasmid replication were identified on the plasmid genome. One region was located on a 4.66-kb segment of an EcoR1 fragment at map coordinates 73.87 to 78.53 kb. Another was located within an 8.05-kb segment of an EcoR1 fragment at map coordinates 113.40 to 121.45. This region was very unstable but, when ligated to the 3.21-kb EcoR1 fragment E13 located at map coordinates 18.83 to 22.06 kb, replication was stable. Thus, at least three regions of R124 widely separated around the genome are associated with plasmid replication and stable maintenance. Each of these three regions expressed incompatibility with R124. The Tc resistance gene of R124 was located on the contiguous EcoR1 fragments E8 and E12 located at map coordinates 100.49 to 113.40.     

Rapid recycling of triose phosphates in oak stem tissue

We report the carbon-13 and oxygen-18 isotope ratios in cellulose from the early and late wood of pedunculate oak (Quercus robur L.). The δ¹³ C value of the early wood correlates best with that of the late wood of the previous year. The δ¹⁸O value of the early wood correlates best with that of the late wood of the same year. We suggest that a biochemical explanation of these data is that there is a rapid cycle between hexose monophosphates and triose phosphates in oak stem tissue during cellulose synthesis. Evidence in support of this explanation is provided by the intramolecular distribution of ¹⁴C in labelled fructose extracted from cores of wood that had been supplied with [1?¹⁴C]- and [6-¹⁴C]glucose.     

Resource partitioning of the host fungus Coriolus versicolor by two ciid beetles: the role of odour compounds and host ageing

The ciid beetles Octotemnus glabriculus and Cis boleti exploit different developmental stages of fruit bodies of their preferred host fungus Coriolus versicolor . Larvae of the smaller beetle, O. glabriculus , mainly use young, expanding, fruit bodies; adults of O. glabriculus are predominantly found in young fruit bodies. By contrast, adults and larvae of the larger beetle, C. boleti , are prevalent in fully developed fruit bodies of C. versicolor . Because fruit bodies of most genets emerge during spring and early summer and mature by autumn, O. glabriculus and C. boleti breed in separated seasons. Adults and larvae of O. glabriculus are abundant in spring and early summer. By contrast, the number of adults and larvae of C. boleti increases gradually from late spring to summer and peaks in autumn. We conducted a field experiment that suggests that the phenological dynamics of C. versicolor fruit bodies drive the separation of breeding seasons between O. glabriculus and C. boleti . Additionally, laboratory experiments revealed that O. glabriculus and C. boleti have differential behavioural responses to odour compounds from young and mature fruit bodies of C. versicolor . We conclude that age-related changes in the chemical composition of fruit bodies may allow O. glabriculus and C. boleti to discriminate among C. versicolor , thus providing a mechanism for the partitioning of the resource.     

The signal peptide peptidase SppA is involved in sterol regulatory element‐binding protein cleavage and hypoxia adaptation in Aspergillus nidulans

Using forward genetics, we revealed that the signal peptide peptidase (SPP) SppA, an aspartyl protease involved in regulated intramembrane proteolysis (RIP), is essential for hypoxia adaptation in Aspergillus nidulans, as well as hypoxia‐sensitive mutant alleles of a sterol regulatory element‐binding protein (SREBP) srbA and the Dsc ubiquitin E3 ligase complex dscA‐E. Both null and dead activity [D337A] mutants of sppA failed to grow in hypoxia, and the growth defect of ΔsppA was complemented by nuclear SrbA‐N381 expression. Additionally, SppA interacted with SrbA in the endoplasmic reticulum, where SppA localized in normoxia and hypoxia. Expression of the truncated SrbA‐N414 covering the SrbA sequence prior to the second transmembrane region rescued the growth of ΔdscA but not of ΔsppA in hypoxia. Unlike ΔdscA and ΔdscA;ΔsppA double mutants, in which SrbA cleavage was blocked, the molecular weight of cleaved SrbA increased in ΔsppA compared to the control strain in immunoblot analyses. Overall, our data demonstrate the sequential cleavage of SrbA by Dsc‐linked proteolysis followed by SppA, proposing a new model of RIP for SREBP cleavage in fungal hypoxia adaptation. Furthermore, the function of SppA in hypoxia adaptation was consistent in Aspergillus fumigatus, suggesting the potential roles of SppA in fungal pathogenesis.