Phylogenetic relationships of Phyciodes butterfly species (Lepidoptera: Nymphalidae): complex mtDNA variation and species delimitations

Abstract. Mitochondrial DNA variation was studied in the butterfly genus Phyciodes (Lepidoptera: Nymphalidae) by sequencing 1450 bp of the COI gene from 140 individuals of all eleven currently recognized species. The study focused on four species in particular that have been taxonomically difficult for the past century, P. tharos , P. cocyta , P. batesii and P. pulchella . A cladistic analysis of ninety-eight unique haplotypes showed that Phyciodes forms a monophyletic group with P. graphica as the most basal species. Of the three informal species groups described for Phyciodes , only one (the mylitta -group) is unambiguously monophyletic. Within the tharos -group, seven well supported clades were found that correspond to three taxa, P. tharos , P. pulchella and a grade consisting of P. cocyta and P. batesii haplotypes interdigitated with each other. None of the clades is formed exclusively by one species. The patterns of haplotype variation are the result of both retained ancient polymorphism and introgression. Introgression appears to be most common between P. cocyta and P. batesii ; however, these two species occur sympatrically and are morphologically and ecologically distinct, suggesting that the level of current introgression does not seem to be enough to threaten their genetic integrity. The results indicate that mitochondrial DNA sequences must be used with great caution in delimiting species, especially when infraspecific samples are few, or introgression seems to be rampant.     

Lack of CD27-CD45RA-V gamma 9V delta 2+ T cell effectors in immunocompromised hosts and during active pulmonary tuberculosis.

In humans, the circulating pool of mycobacteria-reactive Vgamma9Vdelta2+ T cells is expanded with age and may contribute to Mycobacterium tuberculosis immunosurveillance. We observed that two subsets of Vgamma9Vdelta2+ T cells could be identified on the basis of CD27 expression in immunocompetent adults, showing that functionally differentiated gammadelta T cells have lost CD27 expression. In contrast, the CD27-CD45RA-Vgamma9Vdelta2+ T cell subset of effector cells was absent in cord blood cells from healthy newborns and lacking in the peripheral blood from HIV-infected patients. Moreover, circulating Vgamma9Vdelta2+ T cell effectors were significantly reduced in patients with acute pulmonary tuberculosis, resulting in a reduced frequency of IFN-gamma-producing cells after stimulation with nonpeptidic mycobacterial ligands. These observations indicate that monitoring and boosting gammadelta T cell effectors could be clinically relevant both in immunocompromised hosts and during active tuberculosis disease.     

Endothelial-Mesenchymal Transition of Brain Endothelial Cells: Possible Role during Metastatic Extravasation

Cancer progression towards metastasis follows a defined sequence of events described as the metastatic cascade. For extravasation and transendothelial migration metastatic cells interact first with endothelial cells. Yet the role of endothelial cells during the process of metastasis formation and extravasation is still unclear, and the interaction between metastatic and endothelial cells during transendothelial migration is poorly understood. Since tumor cells are well known to express TGF-β, and the compact endothelial layer undergoes a series of changes during metastatic extravasation (cell contact disruption, cytoskeletal reorganization, enhanced contractility), we hypothesized that an EndMT may be necessary for metastatic extravasation. We demonstrate that primary cultured rat brain endothelial cells (BEC) undergo EndMT upon TGF-β1 treatment, characterized by the loss of tight and adherens junction proteins, expression of fibronectin, β1-integrin, calponin and α-smooth muscle actin (SMA). B16/F10 cell line conditioned and activated medium (ACM) had similar effects: claudin-5 down-regulation, fibronectin and SMA expression. Inhibition of TGF-β signaling during B16/F10 ACM stimulation using SB-431542 maintained claudin-5 levels and mitigated fibronectin and SMA expression. B16/F10 ACM stimulation of BECs led to phosphorylation of Smad2 and Smad3. SB-431542 prevented SMA up-regulation upon stimulation of BECs with A2058, MCF-7 and MDA-MB231 ACM as well. Moreover, B16/F10 ACM caused a reduction in transendothelial electrical resistance, enhanced the number of melanoma cells adhering to and transmigrating through the endothelial layer, in a TGF-β-dependent manner. These effects were not confined to BECs: HUVECs showed TGF-β-dependent SMA expression when stimulated with breast cancer cell line ACM. Our results indicate that an EndMT may be necessary for metastatic transendothelial migration, and this transition may be one of the potential mechanisms occurring during the complex phenomenon known as metastatic extravasation.     

Transport and regulative properties of phenylacetic acid

The mode of transport and regulative properties of phenylacetic acid (PAA) were studied in 11-cm long segments of pea epicotyls capable of growth. The transport of PAA m both the basipetal and aeropetal direction was limited to tissues situated immediately below and/or above the site of its application. PAA was able to promote the flow of¹⁴C-ABA in the acropetal direction. PAA-initiated thickening growth was probably the cause of this promotion. Influence of Auxin-like Substances upon the Transport of¹⁴C-ABA in Long Pea Epicotyl Segments Part III.     

Conformational Analysis of a Synthetic Antimicrobial Peptide in Water and Membrane-Mimicking Solvents: A Molecular Dynamics Simulation Study

We have investigated structural and dynamic properties of the synthetic peptide hlF1-11 (GRRRSVQWCA, i.e., the first 11 N-terminal amino acids of the human lactoferrin protein) in water, 250 mM NaCl solution, 50% (V/V) water–trifluoroethanol mixture, and in the membrane mimetic 4:4:1 methanol–chloroform–water mixture. For comparison, we have also performed analogous simulations for the biologically inactive control peptide featuring Ala substitutions in the 2, 3, 6 and 9 positions of the hlF1-11 sequence. Statistical analyses of the trajectories indicate that only in the membrane-mimicking medium hlF1-11 adopts preferentially a conformation suitable to interact effectively with the membrane. In this conformation the peptide cationic region is rather flexible and elongated, while the C-terminal hydrophobic moiety appears as a more rigid hairpin-shaped loop approximately perpendicular to the cationic region. No such conformation is statistically relevant for the control peptide.     

KCNE1 is an auxiliary subunit of two distinct ion channel superfamilies

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Simplicity or complexity? Important aspects of high nature value grassland management in nature conservation

Biodiversity and Conservation - Local, adaptive traditional grassland management systems have played a fundamental role in the creation, maintenance and conservation of high nature value (HNV)...