No evidence for homosubtypic immunity of influenza H3 in Mallards following vaccination in a natural experimental system

The Mallard (Anas platyrhynchos) is an important reservoir species for influenza A viruses (IAV), and in this host, prevalence and virus diversity are high. Studies have demonstrated the presence of homosubtypic immunity, where individuals are unlikely to be reinfected with the same subtype within an autumn season. Further, evidence for heterosubtypic immunity exists, whereby immune responses specific for one subtype offer partial or complete protection against related HA subtypes. We utilized a natural experimental system to determine whether homo‐ or heterospecific immunity could be induced following experimental vaccination. Thirty Mallards were vaccinated with an inactivated H3, H6 or a sham vaccine and after seroconversion were exposed to naturally infected wild conspecifics. All ducks were infected within 2 days and had both primary and secondary infections. Overall, there was no observable difference between groups; all individuals were infected with H3 and H10 IAV. At the cessation of the experiment, most individuals had anti‐NP antibodies and neutralizing antibodies against H10. Not all individuals had H3 neutralizing antibodies. The isolated H3 IAVs revealed genetic dissimilarity to the H3 vaccine strain, specifically substitutions in the vicinity of the receptor‐binding site. There was no evidence of vaccine‐induced homosubtypic immunity to H3, a likely result of both a poor H3 immune response in the ducks and H3 immune escape. Likewise, there was no observed heterosubtypic protection related to H6 vaccination. This study highlights the need for experimental approaches to assess how exposure to pathogens and resulting immune processes translates to individual and population disease dynamics.     

Comparative genomics reveals new functional insights in uncultured MAST species

Heterotrophic lineages of stramenopiles exhibit enormous diversity in morphology, lifestyle, and habitat. Among them, the marine stramenopiles (MASTs) represent numerous independent lineages that are only known from environmental sequences retrieved from marine samples. The core energy metabolism characterizing these unicellular eukaryotes is poorly understood. Here, we used single-cell genomics to retrieve, annotate, and compare the genomes of 15 MAST species, obtained by coassembling sequences from 140 individual cells sampled from the marine surface plankton. Functional annotations from their gene repertoires are compatible with all of them being phagocytotic. The unique presence of rhodopsin genes in MAST species, together with their widespread expression in oceanic waters, supports the idea that MASTs may be capable of using sunlight to thrive in the photic ocean. Additional subsets of genes used in phagocytosis, such as proton pumps for vacuole acidification and peptidases for prey digestion, did not reveal particular trends in MAST genomes as compared with nonphagocytotic stramenopiles, except a larger presence and diversity of V-PPase genes. Our analysis reflects the complexity of phagocytosis machinery in microbial eukaryotes, which contrasts with the well-defined set of genes for photosynthesis. These new genomic data provide the essential framework to study ecophysiology of uncultured species and to gain better understanding of the function of rhodopsins and related carotenoids in stramenopiles.Subject terms: Genomics, Microbiology     

Clinical considerations on 2 cases of hepatic fascioliasis. Importance of the imaging examinations]

Two cases of hepatic human fascioliasis, both with antecedents of eating watercress, hepatobiliary symptoms and high eosinophilia are described. In the first one (42 year-old male), at the beginning the abdominal ecotomographical and computed tomography images suggested an hepatic tumor, but afterwards, the finding of Fasciola hepatica ova in feces and the observation of numerous typical images of the fluke in the choledochus by means of an endoscopic cholangiography, plus lesions related to a L?ffler syndrome detected in a chest radiography, lead to the diagnosis of hepatic fascioliasis. The patient was treated with dehydroemetine. In the second case (52 year-old male), presented pain in the upper right abdominal quadrant; in an abdominal ecography three cystic lesions in the right liver lobe were found. Nor in the feces neither in the bile F. hepatica eggs were observed. Serological tests for fascioliasis and hydatidosis resulted positive. The endoscopic cholangiography was normal. With the presumptive diagnosis of fascioliasis the patient was treated with dehydroemetine. But as his disturbances remained during the following six months, and raising the possibility of a suppurated hydatid cyst or hepatic abscesses, he was submitted to surgery, finding F. hepatica eggs in the chocolate-like hematic liquid. In the wall and in a liver mass resected a grunuloma with eggs of the parasite was detected. The patient was treated again and cured with dehydroemetine. The existence of subcapsular hematomata and granulomas in hepatic fascioliasis, which can give raise to a diagnosis confusion due to their aspect in the ecotomography and computed tomography are commented. The cholangiographic aspect of the affection is discussed.     

Voltage sensor of ion channels and enzymes

Placed in the cell membrane (a two-dimensional environment), ion channels and enzymes are able to sense voltage. How these proteins are able to detect the difference in the voltage across membranes has attracted much attention, and at times, heated debate during the last few years. Sodium, Ca²⁺ and K⁺ voltage-dependent channels have a conserved positively charged transmembrane (S4) segment that moves in response to changes in membrane voltage. In voltage-dependent channels, S4 forms part of a domain that crystallizes as a well-defined structure consisting of the first four transmembrane (S1–S4) segments of the channel-forming protein, which is defined as the voltage sensor domain (VSD). The VSD is tied to a pore domain and VSD movements are allosterically coupled to the pore opening to various degrees, depending on the type of channel. How many charges are moved during channel activation, how much they move, and which are the molecular determinants that mediate the electromechanical coupling between the VSD and the pore domains are some of the questions that we discuss here. The VSD can function, however, as a bona fide proton channel itself, and, furthermore, the VSD can also be a functional part of a voltage-dependent phosphatase.     

Analysis of mitochondrial DNA in Bolivian llama,alpaca and vicuna populations: a contribution to the phylogeny of the South American camelids

The objectives of this work were to assess the mtDNA diversity of Bolivian South American camelid (SAC) populations and to shed light on the evolutionary relationships between the Bolivian camelids and other populations of SACs. We have analysed two different mtDNA regions: the complete coding region of the MT‐CYB gene and 513 bp of the D‐loop region. The populations sampled included Bolivian llamas, alpacas and vicunas, and Chilean guanacos. High levels of genetic diversity were observed in the studied populations. In general, MT‐CYB was more variable than D‐loop. On a species level, the vicunas showed the lowest genetic variability, followed by the guanacos, alpacas and llamas. Phylogenetic analyses performed by including additional available mtDNA sequences from the studied species confirmed the existence of the two monophyletic clades previously described by other authors for guanacos (G) and vicunas (V). Significant levels of mtDNA hybridization were found in the domestic species. Our sequence analyses revealed significant sequence divergence within clade G, and some of the Bolivian llamas grouped with the majority of the southern guanacos. This finding supports the existence of more than the one llama domestication centre in South America previously suggested on the basis of archaeozoological evidence. Additionally, analysis of D‐loop sequences revealed two new matrilineal lineages that are distinct from the previously reported G and V clades. The results presented here represent the first report on the population structure and genetic variability of Bolivian camelids and may help to elucidate the complex and dynamic domestication process of SAC populations.     

In vivo development of tissue engineered vascular grafts: a fluid-solid-growth model

Biomechanics and Modeling in Mechanobiology - Methods of tissue engineering continue to advance, and multiple clinical trials are underway evaluating tissue engineered vascular grafts (TEVGs)....     

Patterns of puffing activity and chromosomal polymorphism in Drosophila subobscura II. Puffing patterns at the prepupa stage

Puffing activity patterns of the five large polytene chromosomes of Drosophila subobscura were studied during the late third-larval instar and through the prepupal period. A total of 166 loci active in some of the eleven stages studied were described. The distribution of these active loci per chromosome is the following: 25 on chromosome A, 33 on chromosome J, 31 on chromosome U, 34 on chromosome E and 43 on chromosome O. Seven principal patterns of puffing activity were defined taking into account the different curves of the puffing histograms. Gene activities per chromosome as well as total were analysed. Three peaks of gene activity at the beginning, middle and ending of prepupation can be observed. U is the most active chromosome and A (the sex chromosome), and J the least active. Chromosomes E and O show a medium activity. A possible biological explanation for these results is discussed.Publication No. 107, Departamento de Genética, Universidad de Valencia (Spain).