Phage-displayed peptides as capture antigens in an innovative assay for Taenia saginata-infected cattle

Bovine cysticercosis is detected during the routine post mortem examination of carcasses by visual inspection (knife and eye method). However, the sensitivity of this procedure is several times lower than immunoassays, even when it is performed by qualified professionals. In the present study, a new generation capture antigens were screened from a phage display peptide library using antibodies from Taenia saginata-infected animals. Eight phage clones were selected, and one, Tsag 3 (VHTSIRPRCQPRAITPR), produced similar results to the T. saginata metacestode crude antigen (TsCa) when used as a capture antigen in an ELISA. The phage-displayed peptides competed with TsCa for binding sites, reducing the reactivity by approximately 30 %. Alanine scanning indicated that proline, arginine, and serine are important residues for antibody binding. Tsag 1 (HFYQITWLPNTFPAR), the most frequent affinity-selected clone, and Tsag 6 (YRWPSTPSASRQATL) shared similarity with highly conserved proteins from the Taeniidae family with known immunogenicity. Due to their epitopic or mimotopic properties, these affinity-selected phages could contribute to the rational design of an ante mortem immunodiagnosis method for bovine cysticercosis, as well as an epitope-based vaccine to interrupt the taeniosis/cysticercosis complex.     

Steroid Hormones and Facial Traits in The Recognition of A Potential Rival in Men

There is evidence that the cognitive skills that enable an individual to evaluate their own physical characteristics and those of others are an important strategy for recognizing a potential rival in intrasexual competition in humans. It has been shown that these strategies are facilitated by steroid hormones such as testosterone (T) and cortisol (C). This study examines whether men recognize as attractive some facial characteristics of other men that the literature reports as attractive to women when observing the faces of other men, under the hypothesis that the presence of these features indicates a potential rival. The characteristics evaluated were facial fluctuating asymmetry (FA), dominance (D), and assertiveness (A). In addition, we investigated whether the recognition of these facial characteristics depended upon the characteristics of the evaluator, that is, of the man's own FA, D, and A, or on the concentration of T and C in saliva. We found that evaluators with greater FA (asymmetric faces) and lower concentrations of C rated the faces of more symmetrical men as more attractive to women and as the most likely to represent potential rivals. Men with asymmetric faces exhibited higher levels of T than low FA males, although the difference was not significant. Conversely, men with low levels of FA (symmetric) identified the faces of more assertive men as the most attractive to women and the most likely to represent potential rivals. We concluded that men with high FA levels are more prone to recognize a potential rival in others according to female preferences, and this identification enables them to reduce the cost of competition.     

A new ditopic GdIII complex functionalized with an adamantyl moiety as a versatile building block for the preparation of supramolecular assemblies

A dimeric GdAAZTA-like complex (AAZTA is 6-amino-6-methylperhydro-1,4-diazepinetetraacetic acid) bearing an adamantyl group (Gd₂ L1) able to form strong supramolecular adducts with specific hosts such as β-cyclodextrin (β-CD), poly-β-CD, and human serum albumin (HSA) is reported. The relaxometric properties of Gd₂ L1 were investigated in aqueous solution by measuring the ¹H relaxivity as a function of pH, temperature, and magnetic field strength. The relaxivity of Gd₂ L1 (per Gd atom) at 40 MHz and 298 K is 17.6 mM^?1 s^?1, a value that remains almost constant at higher fields owing to the great compactness and rigidity of the bimetallic chelate, resulting in an ideal value for the rotational correlation time for high-field MRI applications (1.5–3.0 T). The noncovalent interaction of Gd₂ L1 with β-CD, poly-β-CD, and HSA and the relaxometric properties of the resulting host–guest adducts were investigated using ¹H relaxometric methods. Relaxivity enhancements of 29 and 108 % were found for Gd₂ L1–β-CD and Gd₂ L1–poly-β-CD, respectively. Binding of Gd₂ L1 to HSA (K _A = 1.2 × 10⁴ M^?1) results in a remarkable relaxivity of 41.4 mM^?1 s^?1 for the bound form (+248 %). The relaxivity is only limited by the local rotation of the complex within the binding site, which decreases on passing from Gd₂ L1–β-CD to Gd₂ L1–HSA. Finally, the applicability of Gd₂ L1 as tumor-targeting agent through passive accumulation of the HSA-bound adduct was evaluated via acquisition of magnetic resonance images at 1 T of B16-tumor-bearing mice. These experiments indicate a considerable signal enhancement (+160 %) in tumor after 60 min from the injection and a very low hepatic accumulation.     

The centrosomal kinase NEK2 is a novel splicing factor kinase involved in cell survival

NEK2 is a serine/threonine kinase that promotes centrosome splitting and ensures correct chromosome segregation during the G2/M phase of the cell cycle, through phosphorylation of specific substrates. Aberrant expression and activity of NEK2 in cancer cells lead to dysregulation of the centrosome cycle and aneuploidy. Thus, a tight regulation of NEK2 function is needed during cell cycle progression. In this study, we found that NEK2 localizes in the nucleus of cancer cells derived from several tissues. In particular, NEK2 co-localizes in splicing speckles with SRSF1 and SRSF2. Moreover, NEK2 interacts with several splicing factors and phosphorylates some of them, including the oncogenic SRSF1 protein. Overexpression of NEK2 induces phosphorylation of endogenous SR proteins and affects the splicing activity of SRSF1 toward reporter minigenes and endogenous targets, independently of SRPK1. Conversely, knockdown of NEK2, like that of SRSF1, induces expression of pro-apoptotic variants from SRSF1-target genes and sensitizes cells to apoptosis. Our results identify NEK2 as a novel splicing factor kinase and suggest that part of its oncogenic activity may be ascribed to its ability to modulate alternative splicing, a key step in gene expression regulation that is frequently altered in cancer cells.     

G-triplex structure and formation propensity

The occurrence of a G-triplex folding intermediate of thrombin binding aptamer (TBA) has been recently predicted by metadynamics calculations, and experimentally supported by Nuclear Magnetic Resonance (NMR), Circular Dichroism (CD) and Differential Scanning Calorimetry (DSC) data collected on a 3′ end TBA-truncated 11-mer oligonucleotide (11-mer-3′-t-TBA). Here we present the solution structure of 11-mer-3′-t-TBA in the presence of potassium ions. This structure is the first experimental example of a G-triplex folding, where a network of Hoogsteen-like hydrogen bonds stabilizes six guanines to form two G:G:G triad planes. The G-triplex folding of 11-mer-3′-t-TBA is stabilized by the potassium ion and destabilized by increasing the temperature. The superimposition of the experimental structure with that predicted by metadynamics shows a great similarity, with only significant differences involving two loops. These new structural data show that 11-mer-3′-t-TBA assumes a G-triplex DNA conformation as its stable form, reinforcing the idea that G-triplex folding intermediates may occur in vivo in human guanine-rich sequences. NMR and CD screening of eight different constructs obtained by removing from one to four bases at either the 3′ and the 5′ ends show that only the 11-mer-3′-t-TBA yields a relatively stable G-triplex.     

Conserved syntenic clusters of protein coding genes are missing in birds

Background

Birds are one of the most highly successful and diverse groups of vertebrates, having evolved a number of distinct characteristics, including feathers and wings, a sturdy lightweight skeleton and unique respiratory and urinary/excretion systems. However, the genetic basis of these traits is poorly understood.

Results

Using comparative genomics based on extensive searches of 60 avian genomes, we have found that birds lack approximately 274 protein coding genes that are present in the genomes of most vertebrate lineages and are for the most part organized in conserved syntenic clusters in non-avian sauropsids and in humans. These genes are located in regions associated with chromosomal rearrangements, and are largely present in crocodiles, suggesting that their loss occurred subsequent to the split of dinosaurs/birds from crocodilians. Many of these genes are associated with lethality in rodents, human genetic disorders, or biological functions targeting various tissues. Functional enrichment analysis combined with orthogroup analysis and paralog searches revealed enrichments that were shared by non-avian species, present only in birds, or shared between all species.

Conclusions

Together these results provide a clearer definition of the genetic background of extant birds, extend the findings of previous studies on missing avian genes, and provide clues about molecular events that shaped avian evolution. They also have implications for fields that largely benefit from avian studies, including development, immune system, oncogenesis, and brain function and cognition. With regards to the missing genes, birds can be considered ‘natural knockouts’ that may become invaluable model organisms for several human diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-014-0565-1) contains supplementary material, which is available to authorized users.     

The role of bronchial epithelial cells in the pathogenesis of COPD in Z-alpha-1 antitrypsin deficiency

Background

Alpha-1 antitrypsin is the main inhibitor of neutrophil elastase in the lung. Although it is principally synthesized by hepatocytes, alpha-1 antitrypsin is also secreted by bronchial epithelial cells. Gene mutations can lead to alpha-1 antitrypsin deficiency, with the Z variant being the most clinically relevant due to its propensity to polymerize. The ability of bronchial epithelial cells to produce Z-variant protein and its polymers is unknown.We investigated the expression, accumulation, and secretion of Z-alpha-1 antitrypsin and its polymers in cultures of transfected cells and in cells originating from alpha-1 antitrypsin-deficient patients.

Methods

Experiments using a conformation-specific antibody were carried out on M- and Z-variant–transfected 16HBE cells and on bronchial biopsies and ex vivo bronchial epithelial cells from Z and M homozygous patients. In addition, the effect of an inflammatory stimulus on Z-variant polymer formation, elicited by Oncostatin M, was investigated. Comparisons of groups were performed using t-test or ANOVA. Non-normally distributed data were assessed by Mann–Whitney U test or the Kruskal-Wallis test, where appropriate. A P value of < 0.05 was considered to be significant.

Results

Alpha-1 antitrypsin polymers were found at a higher concentration in the culture medium of ex vivo bronchial epithelial cells from Z-variant homozygotes, compared with M-variant homozygotes (P < 0.01), and detected in the bronchial epithelial cells and submucosa of patient biopsies. Oncostatin M significantly increased the expression of alpha-1 antitrypsin mRNA and protein (P < 0.05), and the presence of Z-variant polymers in ex vivo cells (P < 0.01).

Conclusions

Polymers of Z-alpha-1 antitrypsin form in bronchial epithelial cells, suggesting that these cells may be involved in the pathogenesis of lung emphysema and in bronchial epithelial cell dysfunction.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0112-3) contains supplementary material, which is available to authorized users.