Refractive index measurement using single fiber reflectance spectroscopy

A method using single fiber reflectance spectroscopy to measure the refractive indices of transparent and turbid media over a broad wavelength range is presented and tested. For transparent liquid samples, the accuracy is within 0.2%, and the accuracy increases with increasing wavelength. For liquid turbid media, the accuracy is within 0.3% and increases with decreasing wavelength. For solid turbid samples, such as human skin, the accuracy critically depends on the optical contact between the fiber and sample surface. It is demonstrated that this technique has the potential to measure refractive indices of biological tissue in vivo.      

Trabecular bone of precocials at birth; Are they prepared to run for the wolf(f)?

Bone is a dynamic tissue adapting to loading according to “Wolff's law of bone adaptation.” During very early life, however, such a mechanism may not be adequate enough to adapt to the dramatic change in environmental challenges in precocial species. Their neonates are required to stand and walk within hours after birth, in contrast to altricial animals that have much more time to adapt from the intrauterine environment to the outside world. In this study, trabecular bone parameters of the talus and sagittal ridge of the tibia from stillborn but full‐term precocials (calves and foals) were analyzed by micro‐CT imaging in order to identify possible anticipatory mechanisms to loading. Calculated average bone volume fraction in the Shetland pony (49–74%) was significantly higher compared to Warmblood foals (28–51%). Bovine trabecular bone was characterized by a low average bone volume fraction (22–28%), however, more directional anisotropy was found. It is concluded that anticipatory strategies in skeletal development exist in precocial species, which differ per species and are most likely related to anatomical differences in joint geometry and related loading patterns. The underlying regulatory mechanisms are still unknown, but they may be based on a genetic blueprint for the development of bone. More knowledge, both about a possible blueprint and its regulation, will be helpful in understanding developmental bone and joint diseases. J. Morphol. 277:948–956, 2016. © 2016 Wiley Periodicals, Inc.     

The Acidic A-Domain of Arabidopsis Toc159 Occurs as a Hyperphosphorylated Protein

The translocon at the outer membrane of the chloroplast assists the import of a large class of preproteins with amino-terminal transit sequences. The preprotein receptors Toc159 and Toc33 in Arabidopsis (Arabidopsis thaliana) are specific for the accumulation of abundant photosynthetic proteins. The receptors are homologous GTPases known to be regulated by phosphorylation within their GTP-binding domains. In addition to the central GTP-binding domain, Toc159 has an acidic N-terminal domain (A-domain) and a C-terminal membrane-anchoring domain (M-domain). The A-domain of Toc159 is dispensable for its in vivo activity in Arabidopsis and prone to degradation in pea (Pisum sativum). Therefore, it has been suggested to have a regulatory function. Here, we show that in Arabidopsis, the A-domain is not simply degraded but that it accumulates as a soluble, phosphorylated protein separated from Toc159. However, the physiological relevance of this process is unclear. The data show that the A-domain of Toc159 as well as those of its homologs Toc132 and Toc120 are targets of a casein kinase 2-like activity.The Toc and Tic complexes cooperate to import nuclear-encoded chloroplast preproteins from the cytosol (Jarvis, 2008; Kessler and Schnell, 2009). Initially, incoming preproteins encounter the receptors Toc159 and Toc34 at the chloroplast surface. Both are GTP-binding proteins and share sequence homology in their G-domains. While Toc34 is anchored in the outer membrane by a short hydrophobic C-terminal tail, the triple-domain Toc159 is inserted via a largely hydrophilic 52-kD M-domain. In addition to the G- and M-domains, Toc159 has a large acidic A-domain covering the N-terminal half of the protein. Arabidopsis (Arabidopsis thaliana) encodes two isoforms of Toc34 (Toc33 and Toc34) and four of Toc159 (Toc159, Toc132, Toc120, and Toc90; Jackson-Constan and Keegstra, 2001). The Toc159 isoforms have a similar domain structure, but they differ from each other in length and sequence of their A-domain (Hiltbrunner et al., 2001a). However, Toc90 does not have an acidic domain at all and only consists of the G- and M-domains (Hiltbrunner et al., 2004). It has been demonstrated that the A-domain of AtToc159 and AtToc132 have properties of intrinsically disordered proteins (Hernández Torres et al., 2007; Richardson et al., 2009), suggesting an involvement of the A-domain in transient and multiple protein-protein interactions possibly with the transit peptides of preproteins. Toc34 and Toc159 together with the Toc75 channel constitute the Toc-core complex (Schleiff et al., 2003) and are required for the accumulation of highly abundant photosynthesis-associated proteins in the chloroplast. The Arabidopsis deletion mutants of Toc33 (ppi1; Jarvis et al., 1998) and Toc159 (ppi2; Bauer et al., 2000) have indicative phenotypes of their role in chloroplast biogenesis, respectively pale green and albino. Complementation experiments of the ppi2 mutant have established that the G- and M-domains have essential functions whereas the A-domain is dispensable (Lee et al., 2003; Agne et al., 2009). In preceding studies, possibly influenced by the model organism and experimental tools, Toc159 occurred in different forms. Initially, Toc159 was identified in pea (Pisum sativum) as an 86-kD protein lacking the entire A-domain (Hirsch et al., 1994; Bolter et al., 1998). In addition to its membrane-associated form, Arabidopsis Toc159 has been found as a soluble protein (Hiltbrunner et al., 2001b). However, the function and the fate of the A-domain as well as that of soluble Toc159 remain unknown and a matter of debate.Not only GTP binding and hydrolysis by the Toc GTPases but also phosphorylation is known as a regulatory mechanism of chloroplast protein import at the Toc complex level (Oreb et al., 2008b). First, some precursor proteins, such as the small subunit of Rubisco, may be phosphorylated in their transit sequence by a cytosolic kinase (Martin et al., 2006). Phosphorylation promotes binding to a 14-3-3 protein and cytosolic Hsp70 in the guidance complex that delivers the phosphorylated preprotein to the Toc complex (May and Soll, 2000). Second, both Toc159 and Toc34 are known to be phosphorylated and independently so by distinct kinases, OEK70 and OEK98, respectively (Fulgosi and Soll, 2002). These two kinase activities have been located to the outer envelope membrane, but their molecular identification is still pending. Phosphorylation of the Toc GTPases may occur in the GTP-binding domains (Oreb et al., 2008a). For Toc34, data on the site (Ser-113 in pea and Ser-181 in Arabidopsis) and effects of phosphorylation are available (Jelic et al., 2002, 2003). It imposes a negative regulation on the Toc complex by inhibiting GTP and preprotein binding to Toc34, reducing its ability to bind Toc159 and to assemble into the Toc complex (Oreb et al., 2008a). The in vivo mutational analysis in Arabidopsis indicated that phosphorylation at Toc34 represents a nonessential mechanism (Aronsson et al., 2006; Oreb et al., 2007). Despite the 86-kD proteolytic fragment of Toc159 being a major phosphoprotein in the pea outer chloroplast membrane (Fulgosi and Soll, 2002), little is known of the molecular and regulatory mechanisms of Toc159 phosphorylation. In this study, we report that the A-domain of Toc159 can be purified as a stable fragment. Moreover, it is hyperphosphorylated, hinting at an important and highly regulated functional role. Our data suggest that Toc159 is the target of casein kinase 2 (CK2)-like and membrane-associated kinase activities.     

Ants exhibit asymmetric hybridization in a mosaic hybrid zone

Research on hybridization between species provides unparalleled insights into the pre‐ and postzygotic isolating mechanisms that drive speciation. In social organisms, colony‐level incompatibilities may provide additional reproductive barriers not present in solitary species, and hybrid zones offer an opportunity to identify these barriers. Here, we use genotyping‐by‐sequencing to sequence hundreds of markers in a hybrid zone between two socially polymorphic ant species, Formica selysi and Formica cinerea. We characterize the zone, determine the frequency of hybrid workers, infer whether hybrid queens or males are produced and investigate whether hybridization is influenced by colony social organization. We also compare cuticular hydrocarbon profiles and aggression levels between the two species. The hybrid zone exhibits a mosaic structure. The asymmetric distribution of hybrids skewed towards F. cinerea suggests a pattern of unidirectional nuclear gene flow from F. selysi into F. cinerea. The occurrence of backcrossed individuals indicates that hybrid queens and/or males are fertile, and the presence of the F. cinerea mitochondrial haplotype in 97% of hybrids shows that successful F1 hybrids will generally have F. cinerea mothers and F. selysi fathers. We found no evidence that social organization contributes to speciation, because hybrids occur in both single‐queen and multiple‐queen colonies. Strongly differentiated cuticular hydrocarbon profiles and heightened interspecific aggression further reveal that species recognition cues are both present and perceived. The discovery of fertile hybrids and asymmetrical gene flow is unusual in ants, and this hybrid zone will therefore provide an ideal system with which to investigate speciation in social insects.     

Definition of the MinimalMEN1Candidate Area Based on a 5-Mb Integrated Map of Proximal 11q13: THE EUROPEAN CONSORTIUM ON MEN1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder with a high penetrance characterized by tumors of the parathyroid glands, the endocrine pancreas, and the anterior pituitary. TheMEN1gene, a putative tumor suppressor gene, has been mapped to a 3- to 8-cM region in chromosome 11q13 but it remains elusive as yet. We have combined the efforts and resources from four laboratories to form the European Consortium on MEN1 with the aims of establishing the genetic and the physical maps of 11q13 and of further narrowing the MEN1 region. A 5-Mb integrated map of the region was established by fluorescencein situhybridization on both metaphase chromosomes and DNA fibers, by hybridization to DNA from somatic cell hybrids containing various parts of human chromosome 11, by long-range restriction mapping, and by characterization of YACs and cosmids. Polymorphic markers were positioned and ordered by physical mapping and genetic linkage in 86 MEN1 families with 452 affected individuals. Two critical recombinants identified in two affected cases placed theMEN1gene in an ≈2-Mb region aroundPYGM,flanked by D11S1883 and D11S449.     

Diversity and dynamics of Antarctic marine microbial eukaryotes under manipulated environmental UV radiation

In the light of the predicted global climate change, it is essential that the status and diversity of polar microbial communities is described and understood. In the present study, molecular tools were used to investigate the marine eukaryotic communities of Prydz Bay, Eastern Antarctica, from November 2002 to January 2003. Additionally, we conducted four series of minicosm experiments, where natural Prydz Bay communities were incubated under six different irradiation regimes, in order to investigate the effects of natural UV radiation on marine microbial eukaryotes. Denaturing gradient gel electrophoresis (DGGE) and 18S rRNA gene sequencing revealed a eukaryotic Shannon diversity index averaging 2.26 and 2.12, respectively. Phylogenetic analysis of 472 sequenced clones revealed 47 phylotypes, belonging to the Dinophyceae, Stramenopiles, Choanoflagellidae, Ciliophora, Cercozoa and Metazoa. Throughout the studied period, three communities were distinguished: a postwinter/early spring community comprising dinoflagellates, ciliates, cercozoans, stramenopiles, viridiplantae, haptophytes and metazoans; a dinoflagellate-dominated community; and a diatom-dominated community that developed after sea ice breakup. DGGE analysis showed that size fraction and time had a strong shaping effect on the community composition; however, a significant contribution of natural UV irradiance towards microeukaryotic community composition could not be detected. Overall, dinoflagellates dominated our samples and their diversity suggests that they fulfill an important role in Antarctic coastal marine ecosystems preceding ice breakup as well as between phytoplankton bloom events.     

n-3 Fatty acids, cardiac arrhythmia and fatal coronary heart disease

n-3 Polyunsaturated fatty acids (n-3 PUFA) are suggested to prevent cardiac death via inhibition of cardiac arrhythmia. In this review we discuss the results of human studies on intake of n-3 PUFAs and heart disease and, more specifically, on cardiac arrhythmia. Observational studies indicate that intake of fish is associated with a lower incidence of fatal coronary heart disease in several populations. These studies are fairly consistent, but people that have a high intake of fatty fish might have a healthier lifestyle in general, and such confounding is difficult to remove completely with statistical adjustments and corrections. Evidence from trials is less clear. In two open label trials in patients with a previous myocardial infarction intake of fish or fish oil prevented fatal coronary heart disease. In contrast, a trial in patients with angina suggested a higher risk of sudden cardiac death in patients taking fish oil. Furthermore, results of trials in patients with an implantable cardioverter defibrillator (ICD) that investigated effects of fish oil on arrhythmia in patients already suffering from ventricular tachycardia are not consistent. Also, studies on relationships between intake of n-3 PUFA from fish and less life-threatening forms of arrhythmia, such as atrial fibrillation and premature ventricular complexes (PVCs) are equivocal. Thus, after 35 years of research the question whether fish prevents heart disease remains unanswered, and an anti-arrhythmic effect of fish oil remains unproven although the idea is still viable and is being actively tested in further trials.     

Morphological and morphometric study of crustacean parasites within the genus Lernaeocera

Two species of Lernaeocera are present in the southeastern North Sea. Lernaeocera lusci infects bib Trisopterus luscus, dragonet Callionymus lyra and sand goby Pomatoschistus minutus. L. Minuta is a junior synonym of L. lusci. The second valid species, L. branchialis, infects whiting Merlangius merlangus. The two species can be morphologically separated by the antennary processes, which are present in L. lusci and absent in L. branchialis. Discriminant functions allow complete separation between L. lusci and L. branchialis. There is high intraspecific, host-dependent variability within L. lusci. Length of L. lusci is significantly influenced by host size, and body form is influenced by the site of attachment of L. lusci on at least one host (bib). It is suggested that L. lusci consists of 3 forms: f. lusci, f. minuta and f. lyra.     

Anti-inflammatory role of the cAMP effectors Epac and PKA: implications in chronic obstructive pulmonary disease

Cigarette smoke-induced release of pro-inflammatory cytokines including interleukin-8 (IL-8) from inflammatory as well as structural cells in the airways, including airway smooth muscle (ASM) cells, may contribute to the development of chronic obstructive pulmonary disease (COPD). Despite the wide use of pharmacological treatment aimed at increasing intracellular levels of the endogenous suppressor cyclic AMP (cAMP), little is known about its exact mechanism of action. We report here that next to the β(2)-agonist fenoterol, direct and specific activation of either exchange protein directly activated by cAMP (Epac) or protein kinase A (PKA) reduced cigarette smoke extract (CSE)-induced IL-8 mRNA expression and protein release by human ASM cells. CSE-induced IκBα-degradation and p65 nuclear translocation, processes that were primarily reversed by Epac activation. Further, CSE increased extracellular signal-regulated kinase (ERK) phosphorylation, which was selectively reduced by PKA activation. CSE decreased Epac1 expression, but did not affect Epac2 and PKA expression. Importantly, Epac1 expression was also reduced in lung tissue from COPD patients. In conclusion, Epac and PKA decrease CSE-induced IL-8 release by human ASM cells via inhibition of NF-κB and ERK, respectively, pointing at these cAMP effectors as potential targets for anti-inflammatory therapy in COPD. However, cigarette smoke exposure may reduce anti-inflammatory effects of cAMP elevating agents via down-regulation of Epac1.