Relevance of Global Forest Change Data Set to Local Conservation: Case Study of Forest Degradation in Masoala National Park,Madagascar

A global data set on forest cover change was recently published and made freely available for use (Hansen et al. 2013. Science 342: 850–853). Although this data set has been criticized for inaccuracies in distinguishing vegetation types at the local scale, it remains a valuable source of forest cover information for areas where local data is severely lacking. Masoala National Park, in northeastern Madagascar, is an example of a region for which very little spatially explicit forest cover information is available. Yet, this extremely diverse tropical humid forest is undergoing a dramatic rate of forest degradation and deforestation through illegal selective logging of rosewood and ebony, slash‐and‐burn agriculture, and damage due to cyclones. All of these processes result in relatively diffuse and small‐scale changes in forest cover. In this paper, we examine to what extent Hansen et al.'s global forest change data set captures forest loss within Masoala National Park by comparing its performance to a locally calibrated, object‐oriented classification approach. We verify both types of classification with substantial ground truthing. We find that both the global and local classifications perform reasonably well in detecting small‐scale slash‐and‐burn agriculture, but neither performs adequately in detecting selective logging. We conclude that since the use of the global forest change data set requires very little technical and financial investment, and performs almost as well as the more resource‐demanding, locally calibrated classification, it may be advantageous to use the global forest change data set even for local conservation purposes.     

Revealing phosphoproteins playing role in tobacco pollen activated in vitro

The transition between the quiescent mature and the metabolically active germinating pollen grain most probably involves changes in protein phosphorylation status, since phosphorylation has been implicated in the regulation of many cellular processes. Given that, only a minor proportion of cellular proteins are phosphorylated at any one time, and that phosphorylated and nonphosphorylated forms of many proteins can co‐exist within a cell, the identification of phosphoproteins requires some prior enrichment from a crude protein extract. Here, we have used metal oxide/hydroxide affinity chromatography (MOAC) based on an aluminum hydroxide matrix for this purpose, and have generated a population of phosphoprotein candidates from both mature and in vitro activated tobacco pollen grains. Both electrophoretic and nonelectrophoretic methods, allied to MS, were applied to these extracts to identify a set of 139 phosphoprotein candidates. In vitro phosphorylation was also used to validate the spectrum of phosphoprotein candidates obtained by the MOAC phosphoprotein enrichment. Since only one phosphorylation site was detected by the above approach, titanium dioxide phosphopeptide enrichment of trypsinized mature pollen crude extract was performed as well. It resulted in a detection of additional 51 phosphorylation sites giving a total of 52 identified phosphosites in this set of 139 phosphoprotein candidates.     

Expression of functional chemokine receptors CXCR3 and CXCR4 on human melanoma cells

Chemokines are secreted into the tumor microenvironment by tumor-infiltrating inflammatory cells as well as by tumor cells. Chemokine receptors mediate agonist-dependent cell responses, including migration and activation of several signaling pathways. In the present study we show that several human melanoma cell lines and melanoma cells on macroscopically infiltrated lymph nodes express the chemokine receptors CXCR3 and CXCR4. Using the highly invasive melanoma cell line BLM, we demonstrate that the chemokine Mig, a ligand for CXCR3, activates the small GTPases RhoA and Rac1, induces a reorganization of the actin cytoskeleton, and triggers cell chemotaxis and modulation of integrin VLA-5- and VLA-4-dependent cell adhesion to fibronectin. Furthermore, the chemokine SDF-1alpha, the ligand of CXCR4, triggered modulation of beta(1) integrin-dependent melanoma cell adhesion to fibronectin. Additionally, Mig and SDF-1alpha activated MAPKs p44/42 and p38 on melanoma cells. Expression of functional CXCR3 and CXCR4 receptors on melanoma cells indicates that they might contribute to cell motility during invasion as well as to regulation of cell proliferation and survival.     

A pigtailed macaque model of Kyasanur Forest disease virus and Alkhurma hemorrhagic disease virus pathogenesis

Kyasanur Forest disease virus (KFDV) and the closely related Alkhurma hemorrhagic disease virus (AHFV) are emerging flaviviruses that cause severe viral hemorrhagic fevers in humans. Increasing geographical expansion and case numbers, particularly of KFDV in southwest India, class these viruses as a public health threat. Viral pathogenesis is not well understood and additional vaccines and antivirals are needed to effectively counter the impact of these viruses. However, current animal models of KFDV pathogenesis do not accurately reproduce viral tissue tropism or clinical outcomes observed in humans. Here, we show that pigtailed macaques (Macaca nemestrina) infected with KFDV or AHFV develop viremia that peaks 2 to 4 days following inoculation. Over the course of infection, animals developed lymphocytopenia, thrombocytopenia, and elevated liver enzymes. Infected animals exhibited hallmark signs of human disease characterized by a flushed appearance, piloerection, dehydration, loss of appetite, weakness, and hemorrhagic signs including epistaxis. Virus was commonly present in the gastrointestinal tract, consistent with human disease caused by KFDV and AHFV where gastrointestinal symptoms (hemorrhage, vomiting, diarrhea) are common. Importantly, RNAseq of whole blood revealed that KFDV downregulated gene expression of key clotting factors that was not observed during AHFV infection, consistent with increased severity of KFDV disease observed in this model. This work characterizes a nonhuman primate model for KFDV and AHFV that closely resembles human disease for further utilization in understanding host immunity and development of antiviral countermeasures.     

Photoreceptor projection and termination pattern in the lamina of gonodactyloid stomatopods (mantis shrimp)

The apposition compound eyes of gonodactyloid stomatopods are divided into a ventral and a dorsal hemisphere by six equatorial rows of enlarged ommatidia, the mid-band (MB). Whereas the hemispheres are specialized for spatial vision, the MB consists of four dorsal rows of ommatidia specialized for colour vision and two ventral rows specialized for polarization vision. The eight retinula cell axons (RCAs) from each ommatidium project retinotopically onto one corresponding lamina cartridge, so that the three retinal data streams (spatial, colour and polarization) remain anatomically separated. This study investigates whether the retinal specializations are reflected in differences in the RCA arrangement within the corresponding lamina cartridges. We have found that, in all three eye regions, the seven short visual fibres (svfs) formed by retinula cells 1–7 (R1–R7) terminate at two distinct lamina levels, geometrically separating the terminals of photoreceptors sensitive to either orthogonal e-vector directions or different wavelengths of light. This arrangement is required for the establishment of spectral and polarization opponency mechanisms. The long visual fibres (lvfs) of the eighth retinula cells (R8) pass through the lamina and project retinotopically to the distal medulla externa. Differences between the three eye regions exist in the packing of svf terminals and in the branching patterns of the lvfs within the lamina. We hypothesize that the R8 cells of MB rows 1–4 are incorporated into the colour vision system formed by R1–R7, whereas the R8 cells of MB rows 5 and 6 form a separate neural channel from R1 to R7 for polarization processing.This research was supported by the Swiss National Science Foundation (PBSKB-104268/1), the Australian Research Council (LP0214956) and the American Air Force (AOARD/AFOSR) (F62562-03-P-0227).     

Characterizing associations and SNP-environment interactions for GWAS-identified prostate cancer risk markers--results from BPC3

Genome-wide association studies (GWAS) have identified multiple single nucleotide polymorphisms (SNPs) associated with prostate cancer risk. However, whether these associations can be consistently replicated, vary with disease aggressiveness (tumor stage and grade) and/or interact with non-genetic potential risk factors or other SNPs is unknown. We therefore genotyped 39 SNPs from regions identified by several prostate cancer GWAS in 10,501 prostate cancer cases and 10,831 controls from the NCI Breast and Prostate Cancer Cohort Consortium (BPC3). We replicated 36 out of 39 SNPs (P-values ranging from 0.01 to 10⁻²⁸). Two SNPs located near KLK3 associated with PSA levels showed differential association with Gleason grade (rs2735839, P = 0.0001 and rs266849, P = 0.0004; case-only test), where the alleles associated with decreasing PSA levels were inversely associated with low-grade (as defined by Gleason grade <8) tumors but positively associated with high-grade tumors. No other SNP showed differential associations according to disease stage or grade. We observed no effect modification by SNP for association with age at diagnosis, family history of prostate cancer, diabetes, BMI, height, smoking or alcohol intake. Moreover, we found no evidence of pair-wise SNP-SNP interactions. While these SNPs represent new independent risk factors for prostate cancer, we saw little evidence for effect modification by other SNPs or by the environmental factors examined.     

Antheseabhängige UV-Muster in Blütenständen von Asteraceen

The pseudanthia ofHeliopsis scabra andRudbeckia vulgaris (Asteraceae) were examined during the anthesis for differences in their UV patterns. Distinct changes in the reflectance and absorbance properties could be observed. The results suggest a close correlation between different stages of floral development and pollinator attraction.

Herrn Prof. Dr.Lothar Geitler zum 90. Geburtstag gewidmet.     

Single amino acids in the lumenal loop domain influence the stability of the major light-harvesting chlorophyll a/b complex

The major light-harvesting complex of photosystem II (LHCIIb) is one of the most abundant integral membrane proteins. It greatly enhances the efficiency of photosynthesis in green plants by binding a large number of accessory pigments that absorb light energy and conduct it toward the photosynthetic reaction centers. Most of these pigments are associated with the three transmembrane and one amphiphilic alpha helices of the protein. Less is known about the significance of the loop domains connecting the alpha helices for pigment binding. Therefore, we randomly exchanged single amino acids in the lumenal loop domain of the bacterially expressed apoprotein Lhcb1 and then reconstituted the mutant protein with pigments in vitro. The resulting collection of mutated recombinant LHCIIb versions was screened by using a 96-well-format plate-based procedure described previously [Heinemann, B., and Paulsen, H. (1999) Biochemistry 38, 14088-14093], enabling us to test several thousand mutants for their ability to form stable pigment-protein complexes in vitro. At least one-third of the positions in the loop domain turned out to be sensitive targets; i.e., their exchange abolished formation of LHCIIb in vitro. This confirms our earlier notion that the LHCIIb loop domains contribute more specifically to complex formation and/or stabilization than by merely connecting the alpha helices. Among the target sites, glycines and hydrophilic amino acids are more prominently represented than hydrophobic ones. Specifically, the exchange of any of the three acidic amino acids in the lumenal loop abolishes reconstitution of stable pigment-protein complexes, suggesting that ionic interactions with other protein domains are important for correct protein folding or complex stabilization. One hydrophobic amino acid, tryptophan in position 97, has been hit repeatedly in independent mutation experiments. From the LHCIIb structure and previous mutational analyses, we propose a stabilizing interaction between this amino acid and F195 near the C-proximal end of the third transmembrane helix.     

Peroxiredoxin I and II in Human Eyes: Cellular Distribution and Association with Pterygium and DNA Damage

Peroxiredoxin I and II are both 2-Cys members of the peroxiredoxin family of antioxidant enzymes and inactivate hydrogen peroxide. On western blotting, both enzymes appeared as 22-kD proteins and were present in the sclera, retina and iris. Immunohistochemistry showed strong cytoplasmic labeling in the basal cells of the corneal epithelial layer and the corneoscleral limbus. The melanocytes within the stroma of the iris and the anterior epithelial cells of the lens also showed strong cytoplasmic labeling. The fibrous structure of the stroma and the posterior surface of the ciliary body were also labeled. There was also strong labeling for both enzymes in the photoreceptors and the inner and outer plexiform layers of the retina. There was increased labeling of peroxiredoxin I and II in pterygium. In normal conjunctiva and cornea, only the basal cell layer showed labeling for peroxiredoxin I and II, whereas, in pterygia, there was strong cytoplasmic labeling in most cells involving the full thickness of the epithelium. Co-localization of the DNA oxidation product 8-hydroxy-2’-deoxyguanosine antibody with the nuclear dye 4’,6’-diamidino-2-phenylindole dihydrochloride indicated that the majority of the oxidative damage was cytoplasmic; this suggested that the mitochondrial DNA was most affected by the UV radiation in this condition.