A trnL-F based phylogeny for species ofPelargonium (Geraniaceae) with small chromosomes

Phylogenetic analysis was performed of 921 positions of trnL (UAA) 5 exon — trnF (GAA) exon chloroplast DNA regions from 68 representatives ofPelargonium sectt.Campylia, Cortusina, Glaucophyllum, Hoarea, Isopetalum, Ligularia, Otidia, Pelargonium, Peristera, Polyactium, andReniformia, together with five putative outgroup species from sectionsCiconium, Chorisma andJenkinsonia. The total data set therefore comprised 67.2 kb of DNA sequence. Two main ingroup clades were identified: one clade contains sectionsPeristera, Reniformia, andIsopetalum, the other contains sectionsCampylia, Cortusina, Glaucophyllum, Hoarea, Ligularia, Otidia, Pelargonium, Polyactium and two species currently grouped in sect.Peristera. Branching order among five main clades within the latter clade was not resolved. The trnL-F sequence data support monophyly only for sectionsReniformia andHoarea, the remainder of the currently recognized sections ofPelargonium being either paraphyletic or polyphyletic. The data further suggest that sect.Polyactium is diphyletic and that sect.Glaucophyllum is nested within sect.Pelargonium. One relatively derived clade, which represents half of the genus, contains predominantly geophytic and succulent species, occurring in the geographically restricted winter rainfall region of the South African Cape. This pattern is interpreted as reflecting explosive radiation, possibly as an adaptive response to recent aridification in the western Cape.     

A novel helper phage that improves phage display selection efficiency by preventing the amplification of phages without recombinant protein

Phage display is a widely used technology for the isolation of peptides and proteins with specific binding properties from large libraries of these molecules. A drawback of the common phagemid/helper phage systems is the high infective background of phages that do not display the protein of interest, but are propagated due to non-specific binding to selection targets. This and the enhanced growth rates of bacteria harboring aberrant phagemids not expressing recombinant proteins leads to a serious decrease in selection efficiency. Here we describe a VCSM13-derived helper phage that circumvents this problem, because it lacks the genetic information for the infectivity domains of phage coat protein pIII. Rescue of a library with this novel CT helper phage yields phages that are only infectious when they contain a phagemid-encoded pIII-fusion protein, since phages without a displayed protein carry truncated pIII only and are lost upon re-infection. Importantly, the CT helper phage can be produced in quantities similar to the VCSM13 helper phage. The superiority of CT over VCSM13 during selection was demonstrated by a higher percentage of positive clones isolated from an antibody library after two selection rounds on a complex cellular target. We conclude that the CT helper phage considerably improves the efficiency of selections using phagemid-based protein libraries.     

Attenuated mild colonic inflammation and improved survival from severe DSS-colitis of transgenic Cu/Zn-SOD mice

Mucosal tissue damage in chronic inflammatory bowel disease (IBD) is partly caused by an enduring exposure to excessive amounts of reactive oxygen metabolites (ROM). To protect themselves from the toxic effects of ROM, most intestinal cell types constitutively express the highly specific, key ROM-neutralizing cytosolic enzyme Cu/Zn-superoxide dismutase (SOD). Under inflammatory conditions, however, its protein and activity levels have consistently been reported as being decreased. To elucidate a direct functional relationship between intracellular Cu/Zn-SOD expression and intestinal inflammation, we investigated the effects of transgenic human Cu/Zn-SOD overexpression in acute and chronic murine dextran sodium sulfate (DSS)-induced colitis. When subjected to a mild form of acute colitis, the Cu/Zn-SOD overexpressing mice showed a significantly lower colonic activity of neutrophilic myeloperoxidase (MPO) than their nontransgenic littermates. This difference was particularly evident in the male animals. In contrast, a severe acute colitis did not lead to any differences in MPO activity between both groups. Yet, when the animals were subsequently allowed to recover, MPO levels were again significantly lower in the transgenes, suggesting an involvement of Cu/Zn-SOD in, particularly, the clearance of neutrophils. Specific, immunohistochemical identification of neutrophils confirmed the validity of the MPO activity measurements. In addition, transgenic animals showed a remarkable survival benefit from severe DSS colitis over their nontransgenic littermates, particularly during or shortly after the acute inflammatory phase. During the chronic inflammatory phase, which was not characterized by massive neutrophil infiltration, no effects of Cu/Zn-SOD overexpression were noted. Paradoxically, overexpression of Cu/Zn-SOD did not obviously improve the colitis-related (oxidative) injury or symptoms at any stage of the experiment. Surprisingly, however, we did observe a pronounced male gender preference for DSS susceptibility that was reflected by increased male colitis mortality. Our findings provide direct in vivo evidence for a protective, neutrophil-related role for Cu/Zn-SOD in intestinal inflammation. As such, they support the concept of SOD-based (adjunct) antioxidant treatment strategies for inflammatory bowel disease.     

Interactive effects of growth‐limiting N supply and elevated atmospheric CO2 concentration on growth and carbon balance of Plantago major

To assess the interactions between concentration of atmospheric CO₂ and N supply, the response of Plantago major ssp. pleiosperma Pilger to a doubling of the ambient CO₂ concentration of 350 µl l^?1 was investigated in a range of exponential rates of N addition. The relative growth rate (RGR) as a function of the internal plant nitrogen concentration (N_i), was increased by elevated CO₂ at optimal and intermediate N_i. The rate of photosynthesis, expressed per unit leaf area and plotted versus N_i. was increased by 20-30% at elevated CO₂ for N_i above 30 mg N g^?1 dry weight. However, the rate of photosynthesis, expressed on a leaf dry matter basis and plotted versus N_i, was not affected by the CO₂ concentration. The allocation of dry matter between shoot and root was not affected by the CO₂ concentration at any of the N addition rates. This is in good agreement with theoretical models. based on a balance between the rate of photosynthesis of the shoot and the acquisition of N by the roots. The concentration of total nonstructural carbohydrates (TNC) was increased at elevated CO₂ and at N limitation, resulting in a shift in the partitioning of photosynthates from structural to nonstructural and, in terms of carbon balance, unproductive dry matter. The increase in concentration of TNC led to a decrease in both specific leaf area (SLA) and N_i at all levels of nutrient supply, and was the cause of the increased rate of photosynthesis per unit leaf area. Correction of the relationship between RGR and Ni for the accumulation of TNC made the effect of elevated CO₂ on the relationship between RGR and N_i disappear. We conclude that the shift in the relationship between RGR and N_i was due to the accumulation of TNC and not due to differences in physiological variables such as photosynthesis and shoot and root respiration, changes in leaf morphology or allocation of dry matter.     

NUCLEAR RIBOSOMAL DNA INTERNAL TRANSCRIBED SPACER REGIONS (ITS1 AND ITS2) DEFINE DISCRETE BIOGEOGRAPHIC GROUPS IN CLADOPHORA ALBIDA (CHLOROPHYTA)1

Nucleotide sequences of the nuclear ribosomal DNA internal transcribed spacers (ITS1 and ITS2), the 5.8S, and short stretches of the adjacent 18S and 26S coding regions were determined in isolates from four disjunct Cladophora albida (Huds.) Kütz. populations (NE-America, W-Europe, Japan, and W-Australia). The two Pacific isolates share nearly identical ITS sequences as do the two Atlantic isolates. In contrast, interoceanic comparisons exhibit a 21% sequence difference. Variation within ITS regions is useful for identification of population groups on a regional or oceanic scale. However, both spacers are characterized by numerous repeat motifs as well as point mutations, which result in alignment problems at the interspecific level within Cladophora.     

Effect of glucose fermentation of the functioning of protein H in the excretion of cloacin DF13 by Escherichia coli

Abstract The inhibitory effect of glucose on the excretion of cloacin DF13 by mitomycin C-induced cloacinogenic Escherichia coli cells (Van Tiel-Menkveld et al. (1981) J. Bacteriol. 146, 41–48) was investigated. Cells grown and induced under the same conditions as reported by Van Tiel-Menkveld et al. fermented the glucose added to the culture. The pH of the culture decreased to about 5.2 and fermentation products such as formate, acetate, and lactate accumulated in the culture medium. This resulted in the inhibition of the proteolytic processing of the precursor of the pCloDF13-encoded protein H to its mature form, which is essential for the release of cloacin DF13. In cultures buffered at pH 7.0 these effects were not observed.     

Heterochrony and Early Left-Right Asymmetry in the Development of the Cardiorespiratory System of Snakes

Snake lungs show a remarkable diversity of organ asymmetries. The right lung is always fully developed, while the left lung is either absent, vestigial, or well-developed (but smaller than the right). A ‘tracheal lung’ is present in some taxa. These asymmetries are reflected in the pulmonary arteries. Lung asymmetry is known to appear at early stages of development in Thamnophis radix and Natrix natrix. Unfortunately, there is no developmental data on snakes with a well-developed or absent left lung. We examine the adult and developmental morphology of the lung and pulmonary arteries in the snakes Python curtus breitensteini, Pantherophis guttata guttata, Elaphe obsoleta spiloides, Calloselasma rhodostoma and Causus rhombeatus using gross dissection, MicroCT scanning and 3D reconstruction. We find that the right and tracheal lung develop similarly in these species. By contrast, the left lung either: (1) fails to develop; (2) elongates more slowly and aborts early without (2a) or with (2b) subsequent development of faveoli; (3) or develops normally. A right pulmonary artery always develops, but the left develops only if the left lung develops. No pulmonary artery develops in relation to the tracheal lung. We conclude that heterochrony in lung bud development contributes to lung asymmetry in several snake taxa. Secondly, the development of the pulmonary arteries is asymmetric at early stages, possibly because the splanchnic plexus fails to develop when the left lung is reduced. Finally, some changes in the topography of the pulmonary arteries are consequent on ontogenetic displacement of the heart down the body. Our findings show that the left-right asymmetry in the cardiorespiratory system of snakes is expressed early in development and may become phenotypically expressed through heterochronic shifts in growth, and changes in axial relations of organs and vessels. We propose a step-wise model for reduction of the left lung during snake evolution.     

Hypoxia-mimetic effects in the secretome of human preadipocytes and adipocytes

White adipose tissue (WAT) regulates energy metabolism by secretion of proteins with endocrine and paracrine effects. Dysregulation of the secretome of obesity-associated enlarged WAT may lead to obesity-related disorders. This can be caused by hypoxia as a result of poorly vascularized WAT. The effect of hypoxia on the secretome of human (pre)adipocytes is largely unknown. Therefore, we investigated the effect of CoCl₂, a hypoxia mimetic, on the secretome of human SGBS (pre)adipocytes by a proteomics approach combined with bioinformatic analysis. In addition, regulation of protein secretion was examined by protein turnover experiments. As such, secretome changes were particularly associated with protein down-regulation and extracellular matrix protein dysregulation. The observed up-regulation of collagens in adipocytes may be essential for cell survival while down-regulation of collagens in preadipocytes may indicate a disturbed differentiation process. These CoCl₂-induced changes reflect WAT dysfunction that ultimately may lead to obesity-associated complications. In addition, 9 novel adipocyte secreted proteins were identified from which 6 were regulated by CoCl₂. Mass spectrometry data have been deposited to the ProteomeXchange with identifier PXD000162.     

Metabolomics of prolonged fasting in humans reveals new catabolic markers

Fasting is one of the simplest metabolic challenges that can be performed in humans. We here report for the first time a comprehensive analysis of the human ??fasting metabolome?? obtained from analysis of plasma and urine samples in a small cohort of healthy volunteers, using nuclear magnetic resonance (NMR), gas chromatography- and liquid chromatography-mass spectrometry (GC-MS and LC-MS). Intra- and inter-individual variation of metabolites was on measurement of four overnight fasting samples collected from each volunteer over a four week period. One additional sample per volunteer was collected following a prolonged fasting period of 36?h. Amongst a total of 377 quantified entities in plasma around 44% were shown to change significantly in concentration when volunteers extended fasting from 12 to 36?h. In addition to known markers (plasma free fatty acids, glycerol, ketone bodies) that reflect changes in the body??s fuel management under fasting conditions a wide range of ??new?? entities such as ??-aminobutyrate as well as other amino and keto acids were identified as fasting markers. Based on multiple correlations amongst the metabolites and selected hormones in plasma such as leptin or insulin-like-growth-factor-1 (IGF-1), a robust metabolic network with coherent regulation of a wide range of metabolites could be identified. The metabolomics approach described here demonstrates the plasticity of human metabolism and identifies new and robust markers of the fasting state.