On the purported presence of fossilized collagen fibres in an ichthyosaur and a theropod dinosaur

Since the discovery of exceptionally preserved theropod dinosaurs with soft tissues in China in the 1990s, there has been much debate about the nature of filamentous structures observed in some specimens. Sinosauropteryx was the first non‐avian theropod to be described with these structures, and remains one of the most studied examples. Despite a general consensus that the structures represent feathers or feather homologues, a few identify them as degraded collagen fibres derived from the skin. This latter view has been based on observations of low‐quality images of Sinosauropteryx, as well as the suggestion that because superficially similar structures are seen in Jurassic ichthyosaurs they cannot represent feathers. Here, we highlight issues with the evidence put forward in support of this view, showing that integumentary structures have been misinterpreted based on sedimentary features and preparation marks, and that these errors have led to incorrect conclusions being drawn about the existence of collagen in Sinosauropteryx and the ichthyosaur Stenopterygius. We find that there is no evidence to support the idea that the integumentary structures seen in the two taxa are collagen fibres, and confirm that the most parsimonious interpretation of fossilized structures that look like feather homologues in Sinosauropteryx is that they are indeed the remains of feather homologues.     

Cystathionine β-synthase and cystathionine γ-lyase double gene transfer ameliorate homocysteine-mediated mesangial inflammation through hydrogen sulfide generation

Elevated level of homocysteine (Hcy) induces chronic inflammation in vascular bed, including glomerulus, and promotes glomerulosclerosis. In this study we investigated in vitro mechanism of Hcy-mediated monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) induction and determined the regulatory role of hydrogen sulfide (H?S) to ameliorate inflammation. Mouse glomerular mesangial cells (MCs) were incubated with Hcy (75 μM) and supplemented with vehicle or with H?S (30 μM, in the form of NaHS). Inflammatory molecules MCP-1 and MIP-2 were measured by ELISA. Cellular capability to generate H?S was measured by colorimetric chemical method. To enhance endogenous production of H?S and better clearance of Hcy, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) genes were delivered to the cells. Oxidative NAD(P)H p47(phox) was measured by Western blot analysis and immunostaining. Phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun NH?-terminal kinase (JNK1/2) were measured by Western blot analysis. Our results demonstrated that Hcy upregulated inflammatory molecules MCP-1 and MIP-2, whereas endogenous production of H?S was attenuated. H?S treatment as well as CBS and CSE doubly cDNA overexpression markedly reduced Hcy-induced upregulation of MCP-1 and MIP-2. Hcy-induced upregulation of oxidative p47(phox) was attenuated by H?S supplementation and CBS/CSE overexpression as well. In addition to that we also detected Hcy-induced MCP-1 and MIP-2 induction was through phosphorylation of ERK1/2 and JNK1/2. Either H?S supplementation or CBS and CSE doubly cDNA overexpression attenuated Hcy-induced phosphorylation of these two signaling molecules and diminished MCP-1 and MIP-2 expressions. Similar results were obtained by inhibition of ERK1/2 and JNK1/2 using pharmacological and small interferring RNA (siRNA) blockers. We conclude that H?S plays a regulatory role in Hcy-induced mesangial inflammation and that ERK1/2 and JNK1/2 are two signaling pathways involved this process.     

Carbon, nitrogen and phosphorus stoichiometry of crustacean zooplankton in the Baltic Sea: implications for nutrient recycling

The carbon (C), nitrogen (N) and phosphorus (P) contents (%of dry weight) of some crustacean zooplankton were studied inthe Baltic Sea. The copepod Acartia sp. had a stable C and Ncontent (48.3 ± 0.8% C, 12.4 ± 0.2% N, C:N ratio4.5 ± 0.1). The P content was variable (1–2%),probably depending on developmental stage and season. Copepodsaccumulating fat, like Pseudocalanus minutus elongatus, hadhigher and more variable C content (50–60%), and lowerN and P content (7–12% N, 0.6–1.5% P). The highestC and lowest N and P contents were found in adult Limnocalanusmacrurus. However, the N:P ratio was apparently independentof fat content and between 14 and 27 for all copepods. The cladoceransBosmina longispina maritima and Evadne nordmanni had lower Ncontent (9.3–10.8%) and higher C:N ratio (5.1–5.7)than Acartia sp. The P content (1.2–1.4%) was similarto Acartia sp. and the N:P ratios (16–19) were in thelower range of that found for the copepods. The N:P ratio wasgenerally somewhat higher in the copepods than in seston, whichmost of the year had nearly Redfield C:N:P ratios. Potentially,nutrient recycling from crustacean zooplankton could enhanceN limitation of phytoplankton, but small stoichiometric differencessuggest that this effect is probably weak. The extent is dependenton the structure of the zooplankton community and the grossgrowth efficiencies. Acartia copepodites, which had nearly RedfieldN:P ratios, would have the opposite effect and enhance P limitationin late summer when seston N:P ratios increased.     

Predictors of post-stroke body temperature elevation

Background

Growing evidence indicates that elevated body temperature after stroke is associated with unfavorable outcome. The aim of the current study was to investigate which factors predict temperature elevation within 48 h of stroke onset. Specifically, we hypothesized that temperature elevation would be associated with stroke symptom severity and that hemorrhagic stroke would cause a more pronounced temperature increase compared to ischemic stroke.

Methods

The medical records of 400 stroke patients were retrospectively reviewed. Multiple linear regression analysis was used to determine which factors were associated with elevated body temperature.

Results

Several factors were significantly associated with peak body temperature (the highest recorded body temperature) within 48 h of stroke onset: stroke severity measured by the National Institutes of Health Stroke Scale (NIHSS) (regression coefficient; (RC) 0.022), female gender (RC 0.157), tympanic/non-rectal temperature reading (RC ?0.265), swallowing difficulties (RC 0.335), intubation (RC 0.470), antipyretic treatment (RC 0.563), and C-reactive protein?>?50 or signs of infection at admission (RC 0.298). Contrary to our expectations, patients with intracerebral hemorrhage did not have higher peak body temperatures than patients with ischemic stroke.

Conclusions

In conclusion, temperature elevation within the first 48 h of stroke onset is common, can be partially predicted using information at admission and is strongly associated with stroke severity. The strong association with stroke severity may, at least partly, explain the previously described association between post-stroke temperature elevation and unfavorable outcome.

     

Fkbp8: novel isoforms, genomic organization, and characterization of a forebrain promoter in transgenic mice

The immunophilin homolog FKBP8 has been implicated in the regulation of apoptosis. Here we show that the 38-kDa form of FKBP8 (FKBP38) derives from a truncated ORF. The extended FKBP8 ORFs are 46 and 44 kDa in mouse and 45 kDa in human. Although the genomic organization of mouse and human FKBP8 is evolutionarily conserved, additional first exons are encoded by the murine locus. A 4.4-kb murine Fkbp8 gene fragment, containing a GC-rich potential promoter, directed expression of a LacZ reporter gene to forebrain neurons in transgenic mice. Expression of the transgene was observed in CA1 pyramidal neurons of the hippocampus in transgenic mice from three lines. One transgenic founder mouse exhibited widespread forebrain expression of the LacZ transgene that resembles the pattern for the endogenous Fkbp8 gene. Thus promoter/enhancer elements for forebrain expression are located around the first exons of the mouse Fkbp8 gene.     

Involvement of CXCR4 Chemokine Receptor in Metastastic HER2-Positive Esophageal Cancer

A functional linkage of the structurally unrelated receptors HER2 and CXCR4 has been suggested for breast cancer but has not been evaluated for esophageal carcinoma. The inhibition of HER2 leads to a reduction of primary tumor growth and metastases in an orthotopic model of esophageal carcinoma. The chemokine receptor CXCR4 has been implicated in metastatic dissemination of various tumors and correlates with poor survival in esophageal carcinoma. The aim of this study was to investigate a correlation between the expression levels of HER2 and CXCR4 and to evaluate the involvemnent of CXCR4-expression in HER2-positive esophageal carcinoma. The effects of HER2-inhibition with trastuzumab and of CXCR4-inhibition with AMD3100 on primary tumor growth, metastatic homing, and receptor expression were evaluated in vitro and in an orthotopic model of metastatic esophageal carcinoma using MRI for imaging. The clinical relevance of HER2- and CXCR4-expression was examined in esophageal carcinoma patients. A significant correlation of HER2- and CXCR4-expression in primary tumor and metastases exists in the orthotopic model. Trastuzumab and AMD3100 treatment led to a significant reduction of primary tumor growth, metastases and micrometastases. HER2-expression was significantly elevated under AMD3100 treatment in the primary tumor and particularly in the metastases. The positive correlation between HER2- and CXCR4-expression was validated in esophageal cancer patients. The correlation of CXCR4- and HER2-expression and the elevation of HER2-expression and reduction of metastases through CXCR4-inhibition suggest a possible functional linkage and a role in tumor dissemination in HER2-positive esophageal carcinoma.     

Seasonal Community and Population Dynamics of Pelagic Bacteria and Archaea in a High Mountain Lake

The seasonal variations in community structure and cell morphology of pelagic procaryotes from a high mountain lake (Gossenköllesee, Austria) were studied by in situ hybridization with rRNA-targeted fluorescently labeled oligonucleotide probes (FISH) and image-analyzed microscopy. Compositional changes and biomass fluctuations within the assemblage were observed both in summer and beneath the winter ice cover and are discussed in the context of physicochemical and biotic parameters. Proteobacteria of the beta subclass (beta-proteobacteria) formed a dominant fraction of the bacterioplankton (annual mean, 24% of the total counts), whereas alpha-proteobacteria were of similar relative importance only during spring (mean, 11%). Bacteria of the Cytophaga-Flavobacterium cluster, although less abundant, constituted the largest fraction of the filamentous morphotypes during most of the year, thus contributing significantly to the total microbial biomass. Successive peaks of threadlike and rod-shaped archaea were observed during autumn thermal mixing and the period of ice cover formation, respectively. A set of oligonucleotide probes targeted to single phylotypes was constructed from 16S rRNA-encoding gene clone sequences. Three distinct populations of uncultivated microbes, affiliated with the alpha- and beta-proteobacteria, were subsequently monitored by FISH. About one-quarter of all of the beta-proteobacteria (range, 6 to 53%) could be assigned to only two phylotypes. The bacterial populations studied were annually recurrent, seasonally variable, and vertically stratified, except during the periods of lake overturn. Their variability clearly exceeded the fluctuations of the total microbial assemblage, suggesting that the apparent stability of total bacterioplankton abundances may mask highly dynamic community fluctuations.Until recently, microbial ecologist studying aquatic bacteria faced a basic dilemma: they could either measure the abundance, biomass, growth rates, activity, etc. of the “average” bacterium under in situ conditions (e.g., see reference 13), ignoring the phylogenetic and physiological diversity of microbial communities, or they could isolate and ecophysiologically characterize individual bacterial strains (e.g., see reference 36) but were then not able to tell if these microorganisms were also common in the environment. Consequently, little knowledge has been gathered about the spatial and temporal abundance fluctuations of defined phylogenetic groups and of individual bacterial species in natural habitats. Molecular biological techniques used to identify microbes in environmental samples have recently provided new tools to study bacterioplankton biodiversity (e.g., see references 1, 9, 14, 15, and 19) and the in situ abundances of bacteria and archaea that could not be adequately distinguished before (2, 4, 5, 25). Microbiologists are now in a position to potentially elucidate the biogeography (24), population dynamics, and successions (28) not only of a few morphologically conspicuous microbes but of a large number of species, most of which might still be uncharacterized.Fluorescence in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes selectively visualizes bacterial cells with defined phylogenetic affiliations (3, 5). Based on a rapidly growing set of 16S (and, to a lesser extend, 23S) rRNA sequence data, it is probably the phylogenetically most sophisticated (22) approach for whole-cell in situ identification. On the other hand, FISH of plankton samples can be performed with minimal laboratory requirements (16), and evaluation relies on epifluorescence microscopy, which is a standard technique of aquatic microbial ecologists, e.g., for counting (30) and sizing (33) of picoplankton. In contrast to other identification approaches, FISH largely conserves the gestalt of the targeted microorganisms, i.e., their morphologies, cell sizes (26, 34), and cellular rRNA content (7, 32). So, despite the limitations of the method (as discussed in reference 5), its potential for the identification and cytometric analysis of planktonic microbes is just about to be recognized.Recent investigations have reported that various freshwater microbial communities are dominated by bacteria which are phylogenetically affiliated with the alpha and beta subclasses of the class Proteobacteria (alpha- and beta-proteobacteria, respectively) and with members of the Cytophaga-Flavobacterium cluster (2, 6, 16, 19). These observations were based on single or short-term sampling schemes. The instantaneous community composition of the bacterioplankton, however, may not be representative for different seasons, and the typical ranges of annual community variability remain to be established.The size distribution of planktonic bacteria, and particularly the appearance of filamentous cells, has come into the focus of aquatic microbial ecology in the context of studies of predator-prey interactions. It has been shown both in the laboratory (18, 37) and in field experiments (20) that the filamentous morphotype is a phenotypic adaptation of some microbes to protistan grazing, but there are probably numerous other causes for bacteria to elongate far beyond their typical sizes (e.g., see reference 23). Threadlike bacteria have been observed throughout the year in the plankton of a hypertrophic lake (41) but were also found in midwinter in an oligotropic alpine lake (31).In earlier studies, we demonstrated FISH to be an appropriate tool for the monitoring of spatial (2) and short-term temporal (26) dynamics of different phylogenetic groups of the planktonic microbial community in a high mountain lake. Here we report on the seasonal and vertical abundance distributions of pelagic members of Bacteria and Archaea in Gossenköllesee and analysis of the community structure at different levels of taxonomic resolution. We applied published domain- and group-specific oligonucleotide probes (5) but also used the sequence information from a 16S rRNA-encoding gene (rDNA) library obtained from Gossenköllesee bacterioplankton 1 year earlier to construct specific probes targeted at individual bacterial populations. Particular attention was paid to the changes in abundance and taxonomic composition of the filamentous bacterial morphotypes which were recognized as a permanently important fraction of the planktonic procaryotes in Gossenköllesee. Additionally, we monitored the seasonal changes in the biomass size distributions of the nonfilamentous fraction of the pelagic microbial community.