Synthesis of Short-Chain Diols and Unsaturated Alcohols from Secondary Alcohol Substrates by the Rieske Nonheme Mononuclear Iron Oxygenase MdpJ

The Rieske nonheme mononuclear iron oxygenase MdpJ of the fuel oxygenate-degrading bacterial strain Aquincola tertiaricarbonis L108 has been described to attack short-chain tertiary alcohols via hydroxylation and desaturation reactions. Here, we demonstrate that also short-chain secondary alcohols can be transformed by MdpJ. Wild-type cells of strain L108 converted 2-propanol and 2-butanol to 1,2-propanediol and 3-buten-2-ol, respectively, whereas an mdpJ knockout mutant did not show such activity. In addition, wild-type cells converted 3-methyl-2-butanol and 3-pentanol to the corresponding desaturation products 3-methyl-3-buten-2-ol and 1-penten-3-ol, respectively. The enzymatic hydroxylation of 2-propanol resulted in an enantiomeric excess of about 70% for the (R)-enantiomer, indicating that this reaction was favored. Likewise, desaturation of (R)-2-butanol to 3-buten-2-ol was about 2.3-fold faster than conversion of the (S)-enantiomer. The biotechnological potential of MdpJ for the synthesis of enantiopure short-chain alcohols and diols as building block chemicals is discussed.     

Lack of the mitochondrial protein acylglycerol kinase causes Sengers syndrome

Exome sequencing of an individual with congenital cataracts, hypertrophic cardiomyopathy, skeletal myopathy, and lactic acidosis, all typical symptoms of Sengers syndrome, discovered two nonsense mutations in the gene encoding mitochondrial acylglycerol kinase (AGK). Mutation screening of AGK in further individuals with congenital cataracts and cardiomyopathy identified numerous loss-of-function mutations in an additional eight families, confirming the causal nature of AGK deficiency in Sengers syndrome. The loss of AGK led to a decrease of the adenine nucleotide translocator in the inner mitochondrial membrane in muscle, consistent with a role of AGK in driving the assembly of the translocator as a result of its effects on phospholipid metabolism in mitochondria.     

Burden of rare sarcomere gene variants in the framingham and jackson heart study cohorts

Rare sarcomere protein variants cause dominant hypertrophic and dilated cardiomyopathies. To evaluate whether allelic variants in eight sarcomere genes are associated with cardiac morphology and function in the community, we sequenced 3,600 individuals from the Framingham Heart Study (FHS) and Jackson Heart Study (JHS) cohorts. Out of the total, 11.2% of individuals had one or more rare nonsynonymous sarcomere variants. The prevalence of likely pathogenic sarcomere variants was 0.6%, twice the previous estimates; however, only four of the 22 individuals had clinical manifestations of hypertrophic cardiomyopathy. Rare sarcomere variants were associated with an increased risk for adverse cardiovascular events (hazard ratio: 2.3) in the FHS cohort, suggesting that cardiovascular risk assessment in the general population can benefit from rare variant analysis.     

Target specificity of an autoreactive pathogenic human γδ-T cell receptor in myositis

In polymyositis and inclusion body myositis, muscle fibers are surrounded and invaded by CD8-positive cytotoxic T cells expressing the αβ-T cell receptor (αβ-TCR) for antigen. In a rare variant of myositis, muscle fibers are similarly attacked by CD8-negative T cells expressing the γδ-TCR (γδ-T cell-mediated myositis). We investigated the antigen specificity of a human γδ-TCR previously identified in an autoimmune tissue lesion of γδ-T cell-mediated myositis. We show that this Vγ1.3Vδ2-TCR, termed M88, recognizes various proteins from different species. Several of these proteins belong to the translational apparatus, including some bacterial and human aminoacyl-tRNA synthetases (AA-RS). Specifically, M88 recognizes histidyl-tRNA synthetase, an antigen known to be also targeted by autoantibodies called anti-Jo-1. The M88 target epitope is strictly conformational, independent of post-translational modification, and exposed on the surface of the respective antigenic protein. Extensive mutagenesis of the translation initiation factor-1 from Escherichia coli (EcIF1), which served as a paradigm antigen with known structure, showed that a short α-helical loop around amino acids 39 to 42 of EcIF1 is a major part of the M88 epitope. Mutagenesis of M88 showed that the complementarity determining regions 3 of both γδ-TCR chains contribute to antigen recognition. M88 is the only known example of a molecularly characterized γδ-TCR expressed by autoaggressive T cells in tissue. The observation that AA-RS are targeted by a γδ-T cell and by autoantibodies reveals an unexpected link between T cell and antibody responses in autoimmune myositis.     

Exploring the Unique N-Glycome of the Opportunistic Human Pathogen Acanthamoeba

Glycans play key roles in host-pathogen interactions; thus, knowing the N-glycomic repertoire of a pathogen can be helpful in deciphering its methods of establishing and sustaining a disease. Therefore, we sought to elucidate the glycomic potential of the facultative amoebal parasite Acanthamoeba. This is the first study of its asparagine-linked glycans, for which we applied biochemical tools and various approaches of mass spectrometry. An initial glycomic screen of eight strains from five genotypes of this human pathogen suggested, in addition to the common eukaryotic oligomannose structures, the presence of pentose and deoxyhexose residues on their N-glycans. A more detailed analysis was performed on the N-glycans of a genotype T11 strain (4RE); fractionation by HPLC and tandem mass spectrometric analyses indicated the presence of a novel mannosylfucosyl modification of the reducing terminal core as well as phosphorylation of mannose residues, methylation of hexose and various forms of pentosylation. The largest N-glycan in the 4RE strain contained two N-acetylhexosamine, thirteen hexose, one fucose, one methyl, and two pentose residues; however, in this and most other strains analyzed, glycans with compositions of Hex_8–9HexNAc₂Pnt_0–1 tended to dominate in terms of abundance. Although no correlation between pathogenicity and N-glycan structure can be proposed, highly unusual structures in this facultative parasite can be found which are potential virulence factors or therapeutic targets.     

Range‐wide patterns of migratory connectivity in the western sandpiper Calidris mauri

Understanding the population dynamics of migratory animals and predicting the consequences of environmental change requires knowing how populations are spatially connected between different periods of the annual cycle. We used stable isotopes to examine patterns of migratory connectivity across the range of the western sandpiper Calidris mauri. First, we developed a winter isotope basemap from stable‐hydrogen (δD), ‐carbon (δ¹³C), and ‐nitrogen (δ¹⁵N) isotopes of feathers grown in wintering areas. δD and δ¹⁵N values from wintering individuals varied with the latitude and longitude of capture location, while δ¹³C varied with longitude only. We then tested the ability of the basemap to assign known‐origin individuals. Sixty percent of wintering individuals were correctly assigned to their region of origin out of seven possible regions. Finally, we estimated the winter origins of breeding and migrant individuals and compared the resulting empirical distribution against the distribution that would be expected based on patterns of winter relative abundance. For breeding birds, the distribution of winter origins differed from expected only among males in the Yukon‐Kuskokwim (Y‐K) Delta and Nome, Alaska. Males in the Y‐K Delta originated overwhelmingly from western Mexico, while in Nome, there were fewer males from western North America and more from the Baja Peninsula than expected. An unexpectedly high proportion of migrants captured at a stopover site in the interior United States originated from eastern and southern wintering areas, while none originated from western North America. In general, we document substantial mixing between the breeding and wintering populations of both sexes, which will buffer the global population of western sandpipers from the effects of local habitat loss on both breeding and wintering grounds.     

Cultivation of Ulva lactuca with manure for simultaneous bioremediation and biomass production

The potential of liquid manure as sole nutrient source for cultivation of Ulva lactuca was investigated with the perspective of utilizing the produced biomass for feed and/or energy. Algae grown with manure demonstrated equal growth rates to algae grown with standard f/2-medium. The optimum manure concentration, expressed as ammonium concentration, was 25?μM. At these conditions, the biomass produced was potentially suitable for anaerobic digestion, due to a relative high carbon/nitrogen ratio (approximately 19). At higher manure concentrations, tissue concentrations of nitrogen, phosphorus, proteins, and amino acids increased, making the biomass less suitable for anaerobic digestion but potentially interesting as a feed supplement. Cultivating U. lactuca with manure as nutrient source has potential in terms of bioremediation as well as production of bioenergy and protein-feed.     

Iterative species distribution modelling and ground validation in endemism research: an Alpine jumping bristletail example

Endemic species play an important role in conservation ecology. However, knowledge of the real distribution and ecology is still scarce for many endemics. The aims of this study were to predict the distribution of the short-range endemic Alpine jumping bristletail Machilis pallida; to evaluate the actual level of endemism via ground validation using an iterative approach for testing the models in field trips and increasing the quality of the prediction step by step; and to test the potential of species distribution modelling for increasing the knowledge about the ecological niche. Based on seven known locations of M. pallida, we used species distribution modelling via Maxent. After a set of seven field trips a new model was built if new locations were found. Three such iterations were performed to increase model quality. We discovered four new locations of M. pallida, increasing the area of known distribution from 470 to 4,890?km². The distribution of M. pallida is thus wider than formerly known, but our results support Eastern Alpine endemism of the species. The knowledge about the ecological niche could be increased due to the newly found locations. Our study showcases the potential of the iterative approach of modelling and ground validation to evaluate the actual level of endemism and the ecological niche in Alpine species and beyond.     

DNA fingerprinting validates seed dispersal curves from observational studies in the neotropical legume parkia

Background

Determining the distances over which seeds are dispersed is a crucial component for examining spatial patterns of seed dispersal and their consequences for plant reproductive success and population structure. However, following the fate of individual seeds after removal from the source tree till deposition at a distant place is generally extremely difficult. Here we provide a comparison of observationally and genetically determined seed dispersal distances and dispersal curves in a Neotropical animal-plant system.

Methodology/Principal Findings

In a field study on the dispersal of seeds of three Parkia (Fabaceae) species by two Neotropical primate species, Saguinus fuscicollis and Saguinus mystax, in Peruvian Amazonia, we observationally determined dispersal distances. These dispersal distances were then validated through DNA fingerprinting, by matching DNA from the maternally derived seed coat to DNA from potential source trees. We found that dispersal distances are strongly right-skewed, and that distributions obtained through observational and genetic methods and fitted distributions do not differ significantly from each other.

Conclusions/Significance

Our study showed that seed dispersal distances can be reliably estimated through observational methods when a strict criterion for inclusion of seeds is observed. Furthermore, dispersal distances produced by the two primate species indicated that these primates fulfil one of the criteria for efficient seed dispersers. Finally, our study demonstrated that DNA extraction methods so far employed for temperate plant species can be successfully used for hard-seeded tropical plants.     

Solid-state NMR sequential assignments of α-synuclein

Parkinson’s disease is amongst the most frequent and most devastating neurodegenerative diseases. It is tightly associated with the assembly of proteins into high-molecular weight protein species, which propagate between neurons in the central nervous system. The principal protein involved in this process is α-synuclein which is a structural component of the Lewy bodies observed in diseased brain. We here present the solid-state NMR sequential assignments of a new fibrillar form of this protein, the first one with a well-ordered and rigid N-terminal part.