Vegetation classification,mapping, and monitoring at Voyageurs National Park,Minnesota: An application of the U.S. National Vegetation Classification

Question: How can the U.S. National Vegetation Classification (USNVC) serve as an effective tool for classifying and mapping vegetation, and inform assessments and monitoring? Location: Voyageurs National Park, northern Minnesota, U.S.A and environs. The park contains 54 243 ha of terrestrial habitat in the sub-boreal region of North America. Methods: We classified and mapped the natural vegetation using the USNVC, with ‘alliance’and ‘association’as base units. We compiled 259 classification plots and 1251 accuracy assessment test plots. Both plot and type ordinations were used to analyse vegetation and environmental patterns. Color infrared aerial photography (1:15840 scale) was used for mapping. Polygons were manually drawn, then transferred into digital form. Classification and mapping products are stored in publicly available databases. Past fire and logging events were used to assess distribution of forest types. Results and Discussion: Ordination and cluster analyses confirmed 49 associations and 42 alliances, with three associations ranked as globally vulnerable to extirpation. Ordination provided a useful summary of vegetation and ecological gradients. Overall map accuracy was 82.4%. Pinus banksiana - Picea mariana forests were less frequent in areas unburned since the 1930s. Conclusion: The USNVC provides a consistent ecological tool for summarizing and mapping vegetation. The products provide a baseline for assessing forests and wetlands, including fire management. The standardized classification and map units provide local to continental perspectives on park resources through linkages to state, provincial, and national classifications in the U.S. and Canada, and to NatureServe's Ecological Systems classification.     

Reconstitution of Formylglycine-generating Enzyme with Copper(II) for Aldehyde Tag Conversion

To further our aim of synthesizing aldehyde-tagged proteins for research and biotechnology applications, we developed methods for recombinant production of aerobic formylglycine-generating enzyme (FGE) in good yield. We then optimized the FGE biocatalytic reaction conditions for conversion of cysteine to formylglycine in aldehyde tags on intact monoclonal antibodies. During the development of these conditions, we discovered that pretreating FGE with copper(II) is required for high turnover rates and yields. After further investigation, we confirmed that both aerobic prokaryotic (Streptomyces coelicolor) and eukaryotic (Homo sapiens) FGEs contain a copper cofactor. The complete kinetic parameters for both forms of FGE are described, along with a proposed mechanism for FGE catalysis that accounts for the copper-dependent activity.     

Rethinking the dispersal of Homo sapiens out of Africa

Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia.     

Generation of transgenic plants expressing plasma membrane-bound antibodies to the environmental pollutant microcystin-LR

In this paper we describe the engineering and regeneration of transgenic tobacco plants expressing a recombinant plasma membrane-retained antibody specific to microcystin-LR (MC-LR), the environmental toxin pollutant produced by cyanobacteria. The antibody was created by a genetic fusion of the antigen binding regions of the microcystin-specific single chain antibody, 3A8, with the constant regions from the murine IgG1κ, Guy’s 13, including a membrane retention sequence at the C-terminal end of the antibody heavy chain. The antibody produced in the leaves was shown to be functional by binding to MC-LR in an ELISA with antibody yields in transgenic plant leaves reaching a maximum of 1.2 μg g⁻¹ leaf f.wt (0.005% total soluble protein). Antibody-MC-LR complexes formed in leaves after addition of MC-LR to hydroponic medium around the roots of transgenic plant cultures.     

Alphaproteobacteria dominate active 2-methyl-4-chlorophenoxyacetic acid herbicide degraders in agricultural soil and drilosphere

2-Methyl-4-chlorophenoxyacetic acid (MCPA) is a widely used phenoxyalkanoic acid herbicide and subject to aerobic microbial degradation. Earthworms stimulate both growth and activity of MCPA-degrading bacteria in soil. Thus, active MCPA degraders in soil and drilosphere (i.e. burrow walls, gut content and cast) were assessed by 16S rRNA stable isotope probing in soil columns under experimental conditions designed to minimize laboratory incubation biases. Agriculturally relevant concentrations of [(13) C]MCPA (20 μg g(dw) (-1)) were degraded in soil within 23 and 27 days in the presence and absence of earthworms respectively. Total 16S rRNA analysis revealed 73 operational taxonomic units indicative of active Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Firmicutes, Gemmatimonadetes, Planctomycetes, Proteobacteria and Verrucomicrobia in soil and drilosphere derived material. Seven operational taxonomic units indicative of Alpha-, Beta-, Gammaproteobacteria and Firmicutes consumed MCPA-[(13) C]. Dominant consumers of MCPA-[(13) C] were Alphaproteobacteria (Sphingomonadaceae and Bradyrhizobiaceae) in soil and drilosphere. Beta- (Comamonadaceae) and Gammaproteobacteria (Xanthomonadaceae) were also important MCPA-[(13) C] consumers in burrow walls only, indicating that earthworms favour betaproteobacterial MCPA degraders. In oxic microcosms with bulk soil, burrow walls and cast, 20 and 300-400 μg g(dw) (-1) [(13) C]MCPA were consumed within 24 h and 20 days respectively. Gut contents did not facilitate the degradation of [(13) C]MCPA. Sphingomonadaceae dominated MCPA-[(13) C] consumers in bulk soil and burrow wall microcosms, while Beta- and Gammaproteobacteria (Burkholderiacea, Comamonadaceae, Oxalobacteraceae and Xanthomonadaceae) dominated MCPA-[(13) C] consumers in microcosms of cast, indicating that the latter taxa are prone to respond to MCPA in cast. The collective data indicated that Alphaproteobacteria are major MCPA degraders in soil and drilosphere.     

Exercise intensity and pacing strategy of a 5-km indoor race walk during a World Record attempt: a case study

The aim of this case study was to describe the physiological and regulatory processes, by means of heart rate (HR) monitoring and pacing strategy, in a top-level race walker (age: 32 years; height: 1.76 m; body mass: 62 kg; training volume: 130-150 km·wk) who was focused on the attainment of the 5-km indoor race walk (RW) World Record. The HRmean was 185 ± 14.9 b·min, with an HRmean/HRmax ratio of 0.96. Almost the whole race (91.8%) was performed to an intensity ≥90% of the HRmax; lower intensity work was negligible (8.1%). The race profile was a reverse J-shaped pacing curve; in fact, the athlete completed the first 1,000 m in the fastest time, slowing during the middle 3,000 m, and increasing the speed during the final 1,000 m of the race. Despite the attempt failed (the athlete performed only the 2009 World leading performance, 18 minutes 23 seconds 47 tenths), these data suggest that a more linear strain distribution for the entire performance would be optimal instead of a fast-start strategy, which leads to a drastic decrement of the walking velocity. Moreover, this study supports the use of HR monitoring combined with the regulation of the effort to understand the physiological and regulatory processes during an indoor RW event.     

C17 prevents inflammatory arthritis and associated joint destruction in mice

C17 was first described about ten years ago as a gene expressed in CD34+ cells. A more recent study has suggested a role for C17 in chondrogenesis and development of cartilage. However, based on sequence analysis, we believe that C17 has homology to IL-2 and hence we present the hypothesis that C17 is a cytokine possessing immune-regulatory properties. We provide evidence that C17 is a secreted protein preferentially expressed in chondrocytes, hence in cartilage-rich tissues. Systemic expression of C17 in vivo reduces disease in a collagen antibody-induced arthritis model in mice (CAIA). Joint protection is evident by delayed disease onset, minimal edema, bone protection and absence of diverse histological features of disease. Expression of genes typically associated with acute joint inflammation and erosion of cartilage or bone is blunted in the presence of C17. Consistent with the observed reduction in bone erosion, we demonstrate reduced levels of RANKL in the paws and sera of mice over-expressing C17. Administration of C17 at the peak of disease, however, had no effect on disease progression, indicating that C17's immune-regulatory activity must be most prominent prior to or at the onset of severe joint inflammation. Based on this data we propose C17 as a cytokine that s contributes to immune homeostasis systemically or in a tissue-specific manner in the joint.     

Mitochondrial lipid abnormality and electron transport chain impairment in mice lacking alpha-synuclein

The presynaptic protein alpha-synuclein, implicated in Parkinson disease (PD), binds phospholipids and has a role in brain fatty acid (FA) metabolism. In mice lacking alpha-synuclein (Snca-/-), total brain steady-state mass of the mitochondria-specific phospholipid, cardiolipin, is reduced 22% and its acyl side chains show a 51% increase in saturated FAs and a 25% reduction in essential n-6, but not n-3, polyunsaturated FAs. Additionally, 23% reduction in phosphatidylglycerol content, the immediate biosynthetic precursor of cardiolipin, was observed without alterations in the content of other brain phospholipids. Consistent with these changes, more ordered lipid head group and acyl chain packing with enhanced rotational motion of diphenylhexatriene (DPH) about its long axis were demonstrated in time-resolved DPH fluorescence lifetime experiments. These abnormalities in mitochondrial membrane properties were associated with a 15% reduction in linked complex I/III activity of the electron transport chain, without reductions in mitochondrial number, complex II/III activity, or individual complex I, II, III, or IV activity. Reduced complex I activity is thought to be a critical factor in the development of PD. Thus, altered membrane composition and structure and impaired complex I/III function in Snca-/- brain suggest a relationship between alpha-synuclein's role in brain lipid metabolism, mitochondrial function, and PD.