Reduction of 2-methoxy-1,4-naphtoquinone by mitochondrially-localized Nqo1 yielding NAD+ supports substrate-level phosphorylation during respiratory inhibition

Provision of NAD⁺ for oxidative decarboxylation of alpha-ketoglutarate to succinyl-CoA by the ketoglutarate dehydrogenase complex (KGDHC) is critical for maintained operation of succinyl-CoA ligase yielding high-energy phosphates, a process known as mitochondrial substrate-level phosphorylation (mSLP). We have shown previously that when NADH oxidation by complex I is inhibited by rotenone or anoxia, mitochondrial diaphorases yield NAD⁺, provided that suitable quinones are present (Kiss G et al., FASEB J 2014, 28:1682). This allows for KGDHC reaction to proceed and as an extension of this, mSLP. NAD(P)H quinone oxidoreductase 1 (NQO1) is an enzyme exhibiting diaphorase activity. Here, by using Nqo1^?/? and WT littermate mice we show that in rotenone-treated, isolated liver mitochondria 2-methoxy-1,4-naphtoquinone (MNQ) is preferentially reduced by matrix Nqo1 yielding NAD⁺ to KGDHC, supporting mSLP. This process was sensitive to inhibition by specific diaphorase inhibitors. Reduction of idebenone and its analogues MRQ-20 and MRQ-56, menadione, mitoquinone and duroquinone were unaffected by genetic disruption of the Nqo1 gene. The results allow for the conclusions that i) MNQ is a Nqo1-preferred substrate, and ii) in the presence of suitable quinones, mitochondrially-localized diaphorases other than Nqo1 support NADH oxidation when complex I is inhibited. Our work confirms that complex I bypass can occur by quinones reduced by intramitochondrial diaphorases oxidizing NADH, ultimately supporting mSLP. Finally, it may help to elucidate structure-activity relationships of redox-active quinones with diaphorase enzymes.     

Key biocultural values to guide restoration action and planning in New Zealand

A pluralist and cross‐cultural approach that accommodates differing values while encouraging the collaboration and social cohesion necessary for the complex task of ecological restoration is needed. We used qualitative and quantitative analyses to investigate value assigned to biocultural restoration of coastal forests in northern New Zealand by 26 interviewees from three groups (environmental managers, Māori community members, and community project leaders). Māori community members primarily emphasized the importance of Cultural Stewardship and Use in the restoration process, while placing less emphasis on Ecological Integrity. Otherwise, all participants shared common trends, culminating in three interrelated value sets: (1) Personal Engagement, (2) Connection, and (3) the generation and transfer of Knowledge & Wisdom. These values demonstrate that restoration's benefits to people and community are as significant as its reparations of ecological components. Despite differences, all stakeholders were united in a broadly common goal to restore socio‐ecological systems. Their knowledge and shared passion for conservation signal enormous promise for accelerated and effective restoration of coastal forests, if it is conducted using a pluralistic approach. Because some values expressed were intangible and complex, with cross‐cultural dimensions, current valuation tools used by ecological economists to guide management investment fail to adequately account for, in particular, Māori values of ecological restoration.     

A review of software tools for spell‐checking taxon names in vegetation databases

Correct spelling of taxon names in vegetation databases is a fundamental prerequisite for many data processing steps. However, manual detection and correction of spelling mistakes is inefficient, prone to errors and non‐reproducible, especially when scanning large databases. Here, I review six software tools that spell‐check taxon names in vegetation databases: (1) the Global Names Resolver, (2) the Interim Register of Marine and Nonmarine Genera, (3) the Taxonomic Name Resolution Service and R packages (4) Plantminer, (5) Taxonstand and (6) tpl. In particular, I test their capacity to spell‐check names across the taxonomic ranks and organism groups frequently encountered in vegetation data and challenge their ability to screen names from different geographic regions. Performance by software tools differed widely in these tests. Backed up by multiple reference lists, the Global Names Resolver emerged as the most versatile software tool. All software solutions currently suffer from some minor limitations, including an inability to spell‐check names of hybrid taxa. Furthermore, some spelling mistakes, by their nature, cannot be resolved unambiguously. Given these limitations, taxon names should be spell‐checked with software tools in a semi‐automatic rather than an automatic way.     

Interaction Analysis of a Two-Component System Using Nanodiscs

Two-component systems are the major means by which bacteria couple adaptation to environmental changes. All utilize a phosphorylation cascade from a histidine kinase to a response regulator, and some also employ an accessory protein. The system-wide signaling fidelity of two-component systems is based on preferential binding between the signaling proteins. However, information on the interaction kinetics between membrane embedded histidine kinase and its partner proteins is lacking. Here, we report the first analysis of the interactions between the full-length membrane-bound histidine kinase CpxA, which was reconstituted in nanodiscs, and its cognate response regulator CpxR and accessory protein CpxP. Using surface plasmon resonance spectroscopy in combination with interaction map analysis, the affinity of membrane-embedded CpxA for CpxR was quantified, and found to increase by tenfold in the presence of ATP, suggesting that a considerable portion of phosphorylated CpxR might be stably associated with CpxA in vivo. Using microscale thermophoresis, the affinity between CpxA in nanodiscs and CpxP was determined to be substantially lower than that between CpxA and CpxR. Taken together, the quantitative interaction data extend our understanding of the signal transduction mechanism used by two-component systems.     

Differential diagnostic challenge of chronic neutrophilic leukemia in a patient with prolonged leukocytosis

Our interesting case deals with the clinical and morphological aspects of a chronic neutrophilic leukemia and the critical evaluation of differential diagnosis of leukemoid reaction in bone marrow biopsies.     

TLR2/TLR4-independent neutrophil activation and recruitment upon endocytosis of nucleosomes reveals a new pathway of innate immunity in systemic lupus erythematosus

The nucleosome is a major autoantigen in systemic lupus erythematosus (SLE); it can be detected as a circulating complex in the serum, and nucleosomes have been suggested to play a key role in disease development. In the present study, we show for the first time that physiological concentrations of purified nucleosomes trigger innate immunity. The nucleosomes are endocytosed and induce the direct activation of human neutrophils (polymorphonuclear leukocytes (PMN)) as revealed by CD11b/CD66b up-regulation, IL-8 secretion, and increased phagocytic activity. IL-8 is a neutrophil chemoattractant detected in high concentrations in the sera of patients, and IL-8 secretion might thus result in enhanced inflammation, as observed in lupus patients, via an amplification loop. Nucleosomes act as free complexes requiring no immune complex formation and independently of the presence of unmethylated CpG DNA motifs. Both normal and lupus neutrophils are sensitive to nucleosome-induced activation, and activation is not due to endotoxin or high-mobility group box 1 contamination. In mice, i.p. injection of purified nucleosomes induces neutrophil activation and recruitment in a TLR2/TLR4-independent manner. Importantly, neutrophils have been suggested to link innate and adaptive immunity. Thus, nucleosomes trigger a previously unknown pathway of innate immunity, which may partially explain why peripheral tolerance is broken in SLE patients.