In Vivo Generation of Post-infarct Human Cardiac Muscle by Laminin-Promoted Cardiovascular Progenitors

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α6β2*‐subtype nicotinic acetylcholine receptors are more sensitive than α4β2*‐subtype receptors to regulation by chronic nicotine administration

Nicotinic acetylcholine receptors (nAChR) of the α6β2* subtype (where *indicates the possible presence of additional subunits) are prominently expressed on dopaminergic neurons. Because of this, their role in tobacco use and nicotine dependence has received much attention. Previous studies have demonstrated that α6β2*‐nAChR are down‐regulated following chronic nicotine exposure (unlike other subtypes that have been investigated – most prominently α4β2* nAChR). This study examines, for the first time, effects across a comprehensive chronic nicotine dose range. Chronic nicotine dose–responses and quantitative ligand‐binding autoradiography were used to define nicotine sensitivity of changes in α4β2*‐nAChR and α6β2*‐nAChR expression. α6β2*‐nAChR down‐regulation by chronic nicotine exposure in dopaminergic and optic‐tract nuclei was ≈three‐fold more sensitive than up‐regulation of α4β2*‐nAChR. In contrast, nAChR‐mediated [³H]‐dopamine release from dopamine‐terminal region synaptosomal preparations changed only in response to chronic treatment with high nicotine doses, whereas dopaminergic parameters (transporter expression and activity, dopamine receptor expression) were largely unchanged. Functional measures in olfactory tubercle preparations were made for the first time; both nAChR expression levels and nAChR‐mediated functional measures changed differently between striatum and olfactory tubercles. These results show that functional changes measured using synaptosomal [³H]‐DA release are primarily owing to changes in nAChR, rather than in dopaminergic, function.

     

Relatedness Does not Affect Competitive Behavior of Rival Males or Offspring Growth in Multiply Sired Litters of Bank Voles (Myodes glareolus)

Kin selection operates through the fitness of an organism's relatives. In the polyandry context, kin selection may be observable on the one hand in competition between rival males and, on the other hand, in competition between litter mates. Sperm competition theory predicts that males should invest less into mating when competing for fertilizations against a close relative as compared to an unrelated male. We tested this hypothesis with bank voles (Myodes glareolus) by mating each focal male to two females: one of which had previously mated with a full sibling of the focal male and the other one with a male unrelated to the focal male. However, we found no effect of rival male relatedness on mating behavior or proportion of offspring sired by the 2nd male to mate. Possibly, the probability of successive mating of related males with the same female is too low in natural bank vole populations for selection to have fine‐tuned mating behavior in relation to rival male relatedness. Further, polyandry often results in litters sired by multiple males. Litter mates of such litters have a reduced relatedness and are thus expected to be less cooperative during gestation and lactation, which may impair growth. Following double matings with either two full‐sibling males or two unrelated males, we compared offspring growth at birth and during lactation. Against our prediction, there was no difference in growth between litters sired either by two full‐sibling males or by two unrelated males. Either the conflict was not severe enough to be visible with our sample size (N = 16) or it may have been resolved by maternal control of offspring provisioning.     

Rhinomonas nottbecki n. sp. (Cryptomonadales) and Molecular Phylogeny of the Family Pyrenomonadaceae

The cryptomonad Rhinomonas nottbecki n. sp., isolated from the Baltic Sea, is described from live and fixed cells studied by light, scanning, and transmission electron microscopy together with sequences of the partial nucleus‐ and nucleomorph‐encoded 18S rRNA genes as well as the nucleus‐encoded ITS1, 5.8S, ITS2, and the 5′‐end of the 28S rRNA gene regions. The sequence analyses include comparison with 43 strains from the family Pyrenomonadaceae. Rhinomonas nottbecki cells are dorsoventrally flattened, obloid in shape; 10.0–17.2 μm long, 5.5–8.1 μm thick, and 4.4–8.8 μm wide. The inner periplast has roughly hexagonal plates. Rhinomonas nottbecki cells resemble those of Rhinomonas reticulata, but the nucleomorph 18S rRNA gene of R. nottbecki differs by 2% from that of R. reticulata, while the ITS region by 11%. The intraspecific variability in the ITS region of R. nottbecki is 5%. In addition, the predicted ITS2 secondary structures are different in R. nottbecki and R. reticulata. The family Pyrenomonadaceae includes three clades: Clade A, Clade B, and Clade C. All Rhinomonas sequences branched within the Clade C, while the genus Rhodomonas is paraphyletic. The analyses suggest that the genus Storeatula is an alternating morphotype of the genera Rhinomonas and Rhodomonas and that the family Pyrenomonadaceae includes some species that were described multiple times, as well as novel species.     

Centrosomal Localization of the Psoriasis Candidate Gene Product,CCHCR1, Supports a Role in Cytoskeletal Organization

CCHCR1 (Coiled-Coil α-Helical Rod protein 1), within the major psoriasis susceptibility locus PSORS1, is a plausible candidate gene with the psoriasis associated risk allele CCHCR1*WWCC. Although its expression pattern in psoriatic skin differs from healthy skin and its overexpression influences cell proliferation in transgenic mice, its role as a psoriasis effector gene has remained unsettled. The 5′-region of the gene contains a SNP (rs3130453) that controls a 5′-extended open reading frame and thus the translation of alternative isoforms. We have now compared the function of two CCHCR1 isoforms: the novel longer isoform 1 and the previously studied isoform 3. In samples of Finnish and Swedish families, the allele generating only isoform 3 shows association with psoriasis (P<10⁻⁷). Both isoforms localize at the centrosome, a cell organelle playing a role in cell division. In stably transfected cells the isoform 3 affects cell proliferation and with the CCHCR1*WWCC allele, also apoptosis. Furthermore, cells overexpressing CCHCR1 show isoform- and haplotype-specific influences in the cell size and shape and alterations in the organization and expression of the cytoskeletal proteins actin, vimentin, and cytokeratins. The isoform 1 with the non-risk allele induces the expression of keratin 17, a hallmark for psoriasis; the silencing of CCHCR1 reduces its expression in HEK293 cells. CCHCR1 also regulates EGF-induced STAT3 activation in an isoform-specific manner: the tyrosine phosphorylation of STAT3 is disturbed in isoform 3-transfected cells. The centrosomal localization of CCHCR1 provides a connection to the abnormal cell proliferation and offers a link to possible cellular pathways altered in psoriasis.     

Vitamin D is a major determinant of bone mineral density at school age

Background

Vitamin D insufficiency in children may have long-term skeletal consequences as vitamin D affects calcium absorption, bone mineralization and bone mass attainment.

Methodology/Principal Findings

This school-based study investigated vitamin D status and its association with vitamin D intake and bone health in 195 Finnish children and adolescents (age range 7–19 years). Clinical characteristics, physical activity and dietary vitamin D intake were evaluated. Blood and urine samples were collected for serum 25-hydroxyvitamin D (25-OHD) and other parameters of calcium homeostasis. Bone mineral density (BMD) and body composition were measured with dual-energy X-ray absorptiometry (DXA). Altogether 71% of the subjects were vitamin D insufficient (25-OHD <50 nmol/L). The median 25-OHD was 41 nmol/L for girls and 45 nmol/L for boys, and the respective median vitamin D intakes 9.1 µg/day and 10 µg/day. In regression analysis, after adjusting for relevant factors, 25-OHD concentration explained 5.6% of the variance in lumbar BMD; 25-OHD and exercise together explained 7.6% of the variance in total hip BMD and 17% of the variance in whole body BMD. S-25-OHD was an independent determinant of lumbar spine and whole body BMD and in magnitude surpassed the effects of physical activity.

Conclusions/Significance

Vitamin D insufficiency was common even when vitamin D intake exceeded the recommended daily intake. Vitamin D status was a key determinant of BMD. The findings suggest urgent need to increase vitamin D intake to optimize bone health in children.     

Tumour Targeting with Rationally Modified Cell-Penetrating Peptides

Cell-penetrating peptides (CPPs) are short transport peptides with a well-established ability for delivery of bioactive cargoes inside the cells both, in vitro and in vivo. CPPs enter unselectively in a wide variety of cell lines, this is a desirable property for most in vitro applications, however, in vivo e.g. in tumor models, specific targeted accumulation is required. In order to achieve tumor targeting, a known CPP, YTA4, was modified by prolonging it C-terminally with mainly negatively charged amino acids. Additionally, a matrix metalloproteinase-2 cleavage site was introduced between the CPP and the inactivating sequence. This new peptide, named NoPe, is an inactive pro-form of YTA4. It can be selectively cleaved and thereby activated by MMPs. We have conjugated an imaging agent, fluoresceinyl carboxylic acid, and a cytostatic agent methotrexate, to this activable pro-form. NoPe activation was demonstrated in vitro by recombinant MMP-2 cleavage and the cleavage of the attenuating sequence was abolished with MMP-2 specific inhibitor. Furthermore, the fluoresceinyl-NoPe is selectively accumulated in the tumor tissue in MDA-MB-231 tumor bearing mice after intravenous injection. Thus, this strategy proves to be successful for in vivo tumor imaging.     

Sequence variation patterns along a latitudinal cline in Scots pine (Pinus sylvestris): signs of clinal adaptation?

Adaptive clinal variation is abundant in nature, and its genetic basis is of great interest. The polygenic nature of this variation poses a challenge for identifying the causative loci underlying these adaptations. Here, we have examined the patterns of sequence variation in ten candidate genes for timing of bud set and cold tolerance, traits that form strong latitudinal clines in Scots pine (Pinus sylvestris). A set of reference genes was used for comparison and to infer a simplified demographic background model with approximate Bayesian computation methods. Against the resulting bottleneck model, the neutrality tests show little signs for local adaptation, but species-wide selection is suggested in some of the studied genes. In line with the theoretical expectations, we see little evidence for adaptive differentiation with F _ST methods. Instead, allele frequency clines were found in three genes (dhn1, ftl2, and prr1). Our results add to the discussion on which molecular signals best characterize a gene subject to clinally varying selection. This will be especially relevant when these kinds of observations can be examined in parallel with association study results.     

Geographical divergence in host use ability of a marine herbivore in alga–grazer interaction

When the selective environment differs geographically, local herbivore populations may diverge in their host use ability and adapt locally to exploit the sympatric host population. We tested whether populations of the marine generalist herbivore Idotea baltica have diverged in host us ability and whether they locally adapted to exploit the sympatric population of their main host species, the bladderwrack Fucus vesiculosus. We fed isopods from three local populations reciprocally with the sympatric and two allopatric populations of the host. The bladderwrack populations varied in their quality as food for isopods suggesting variation in the selective environment. The ability to exploit the main host showed considerable divergence among the isopod populations. There was no significant interaction between host and isopod origin, indicating that the patterns observed in the reciprocal feeding experiment could be explained by differences in overall suitability of the hosts and differences in overall performance of the isopod populations. Isopod population that was sympatric to a bladderwrack population with low phlorotannin content showed high performance on the algae from the sympatric but low performance on the algae from the two allopatric populations. Performance of isopods, especially in this population, decreased quickly with the increasing phlorotannin content of food algae. We therefore hypothesize that the isopods adapted to a low phlorotannin content were unable to utilize high-phlorotannin algae efficiently. Isopod populations sympatric to the high-phlorotannin bladderwrack populations may be generally better adapted to deal with phlorotannins, being thereby able to utilize a range of bladderwrack populations.