305 research outputs found
The Bag320 satellite DNA family in Bacillus stick insects (Phasmatodea): Different rates of molecular evolution of highly repetitive DNA in bisexual and parthenogenetic taxa
The Bag320 satellite DNA (satDNA) family was studied in seven populations of the stick insects Bacillus atticus (parthenogenetic, unisexual) and Bacillus grandii (bisexual). It was characterized as widespread in all zymoraces of B. atticus and in all subspecies of B. grandii. The copy number of this satellite is higher in the bisexual B. grandii (15%-20% of the genome) than in the parthenogenetic B. atticus (2%- 5% of the genome). The nucleotide sequences of 12 Bag320 clones from B. atticus and 17 from B. grandii differed at 13 characteristic positions by fixed nucleotide substitutions. Thus, nucleotide sequences from both species cluster conspecifically in phylogenetic dendrograms. The nucleotide sequences derived from B. grandii grandii could he clearly discriminated from those of B. grandii benazzii and B. grandii maretimi on the basis of 25 variable sites, although all taxa come from Sicily. In contrast, the Bag320 sequences from B. atticus could not he discriminated accordingly, although they derive from geographically quite distant populations of its three zymoraces (the Italian and Greek B. atticus atticus, the Greek and Turkish B. atticus carius, and the Cyprian B. atticus cyprius). The different rate of evolutionary turnover of the Bag320 satDNA in both species can he related to their different modes of reproduction. This indicates that meiosis and chromosome segregation affect processes in satDNA diversification
Parental species and hybrid descendants of Bacillus (Insecta Phasmatodea) show different patterns of highly amplified, colocalized ribosomal and telomeric sequences
We investigated by dual-color fluorescence in situ hybridization (FISH) with 28S ribosomal and (TTAGG)n telomeric probes all species of the circum-Mediterranean genus Bacillus encompassing bisexual and parthenogenetic taxa, namely the three parental species (B. grandii, B. atticus, B. rossius) and the two derived hybrids (B. whitei, B. lynceorum). Specimens were collected in Italian mainland, Sardinia and Sicily. In all species the presence of colocalized, highly amplified ribosomal and telomeric sequences was demonstrated by the double labelling of the cytological satellites. These satellites varied in size, number and location both among and within species. In B. grandii and B. atticus a maximum of two FISH-labeled locations were observed, whereas in B. rossius and in the two hybrids up to 11 different positions were recorded. Moreover, our investigations showed a significant occurrence of chromosome breakages and rearrangements. The overall meaning of the ribosomal and telomeric sequence colocalization as well as the Nucleolar Organizer Region mobility and activity are discussed in both the ancestors and their hybrid descendants. It is noteworthy that the same trait has been shown in seven additional phasmid species belonging to distantly related genera. This trait could be a shared ancestral character in phasmids
Pathways of 4-hydroxy-2-nonenal detoxification in a human astrocytoma cell line
One of the consequences of the increased level of oxidative stress that often characterizes the cancer cell environment is the abnormal generation of lipid peroxidation products, above all 4-hydroxynonenal. The contribution of this aldehyde to the pathogenesis of several diseases is well known. In this study, we characterized the ADF astrocytoma cell line both in terms of its pattern of enzymatic activities devoted to 4-hydroxynonenal removal and its resistance to oxidative stress induced by exposure to hydrogen peroxide. A comparison with lens cell lines, which, due to the ocular function, are normally exposed to oxidative conditions is reported. Our results show that, overall, ADF cells counteract oxidative stress conditions better than normal cells, thus confirming the redox adaptation demonstrated for several cancer cells. In addition, the markedly high level of NADP+-dependent dehydrogenase activity acting on the glutahionyl-hydroxynonanal adduct detected in ADF cells may promote, at the same time, the detoxification and recovery of cell-reducing power in these cells
Evolution of alternative reproductive systems in Bacillus stick insects.
Reproduction is a key feature of all organisms, yet the way in which it is achieved varies greatly across the tree of life. One striking example of this variation is the stick insect genus Bacillus, in which five different reproductive modes have been described: sex, facultative and obligate parthenogenesis, and two highly unusual reproductive modes: hybridogenesis and androgenesis. Under hybridogenesis, the entire genome from the paternal species is eliminated and replaced each generation by mating with the corresponding species. Under androgenesis, an egg is fertilized, but the developing diploid offspring bear two paternal genomes and no maternal genome, as a consequence of unknown mechanisms. Here, we reevaluate the previous descriptions of Bacillus lineages and the proposed F1 hybrid ancestries of the hybridogenetic and obligately parthenogenetic lineages (based on allozymes and karyotypes) from Sicily, where all these reproductive modes are found. We generate a chromosome-level genome assembly for a facultative parthenogenetic species (B. rossius) and combine extensive field sampling with RADseq and mtDNA data. We identify and genetically corroborate all previously described species and confirm the ancestry of hybrid lineages. All hybrid lineages have fully retained their F1 hybrid constitution throughout the genome, indicating that the elimination of the paternal genome in hybridogens is always complete and that obligate parthenogenesis in Bacillus hybrid species is not associated with an erosion of heterozygosity as known in other hybrid asexuals. Our results provide a stepping stone toward understanding the transitions between reproductive modes and the proximate mechanisms of genome elimination
Assessment of the antibiotic resistance profile, genetic heterogeneity and biofilm production of methicillin-resistant staphylococcus aureus (MRSA) isolated from the italian swine production chain
The main aim of the present study was to evaluate the level of antibiotic resistance, prevalence and virulence features of methicillin-resistant Staphylococcus aureus (MRSA) isolated from heavy swine at abattoir level and farming environments in Lombardy (Northern Italy). With this scope, 88 different heavy swine farms were surveyed, obtaining a total of n = 440 animal swabs and n = 150 environmental swabs. A total of n = 87 MRSA isolates were obtained, with an overall MRSA incidence of 17.50% (n = 77) among animal samples and a 6.67% (n = 10) among environmental. Molecular characterisation using multilocus sequence typing (MLST) plus spa-typing showed that sequence type ST398/t899 and ST398/t011 were the most commonly isolated genotypes, although other relevant sequence types such as ST1 or ST97 were also found. A lack of susceptibility to penicillins, tetracycline and ceftiofur was detected in >91.95, 85.05 and 48.28% of the isolates, respectively. Resistance to doxycycline (32.18%), enrofloxacin (27.59%) and gentamicin (25.29%) was also observed. Additionally, a remarkable level of antibiotic multiresistance (AMR) was observed representing a 77.01% (n = 67) of the obtained isolates. Genetic analysis revealed that 97.70% and 77.01% of the isolates harboured at least one antibiotic resistance or enterotoxin gene, respectively, pointing out a high isolate virulence potential. Lastly, 55.17% (n = 48) were able to produce measurable amounts of biofilm after 24 h. In spite of the current programmes for antibiotic reduction in intensively farming, a still on-going high level of AMR and virulence potential in MRSA was demonstrated, making this pathogen a serious risk in swine production chain, highlighting once more the need to develop efficient, pathogen-specific control strategies
Executive functions in children with specific learning disorders: Shedding light on a complex profile through teleassessment
Executive Functions (EFs) are high-order cognitive processes relevant to learning and adaptation and frequently impaired in children with specific learning disorders (SLDs). This study aimed to investigate EFs in children with SLD and explore the role of specific EF-related subprocesses, such as stimuli processing and processing speed. Fifty-seven SLD and 114 typically developing (TD) children, matched for gender and age, completed four tasks measuring response inhibition, interference control, shifting, and updating on a web-based teleassessment platform. The results show that SLD children performed lower in all EF tasks than TD children, regardless of stimulus type and condition. Mediation analyses suggested that differences between the SLD and TD groups are mediated by EF-related subprocesses, offering an interpretative model of EF deficits in children with SLD
A20, a modulator of smooth muscle cell proliferation and apoptosis, prevents and induces regression of neointimal hyperplasia
A20 is a NFâÎșBâdependent gene that has dual antiâinflammatory and antiapoptotic functions in endothelial cells (EC). The function of A20 in smooth muscle cells (SMC) is unknown. We demonstrate that A20 is induced in SMC in response to inflammatory stimuli and serves an antiâinflammatory function via blockade of NFâÎșB and NFâÎșBâdependent proteins ICAMâ1 and MCPâ1. A20 inhibits SMC proliferation via increased expression of cyclinâdependent kinase inhibitors p21waf1 and p27kip1. Surprisingly, A20 sensitizes SMC to cytokineâ and Fasâmediated apoptosis through a novel NOâdependent mechanism. In vivo, adenoviral delivery of A20 to medial rat carotid artery SMC after balloon angioplasty prevents neointimal hyperplasia by blocking SMC proliferation and accelerating reâendothelialization, without causing apoptosis. However, expression of A20 in established neointimal lesions leads to their regression through increased apoptosis. This is the first demonstration that A20 exerts two levels of control of vascular remodeling and healing. A20 prevents neointimal hyperplasia through combined antiâinflammatory and antiproliferative functions in medial SMC. If SMC evade this first barrier and neointima is formed, A20 has a therapeutic potential by uniquely sensitizing neointimal SMC to apoptosis. A20âbased therapies hold promise for the prevention and treatment of neointimal disease.âPatel, V. I., Daniel, S., Longo, C. R., Shrikhande, G. V., Scali, S. T., Czismadia, E., Groft, C. M., Shukri, T., MotleyâDore, C., Ramsey, H. E., Fisher, M. D., Grey, S. T., Arvelo, M. B., Ferran, C. A20, a modulator of smooth muscle cell proliferation and apoptosis, prevents and induces regression of neointimal hyperplasia. FASEB J. 20, 1418â1430 (2006)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154452/1/fsb2fj054981com.pd
Superhydrophobic lab-on-chip measures secretome protonation state and provides a personalized risk assessment of sporadic tumour
Secretome of primary cultures is an accessible source of biological markers compared to more complex and less decipherable
mixtures such as serum or plasma. The protonation state (PS) of secretome reflects the metabolism of cells and can be used for
cancer early detection. Here, we demonstrate a superhydrophobic organic electrochemical device that measures PS in a drop of
secretome derived from liquid biopsies. Using data from the sensor and principal component analysis (PCA), we developed
algorithms able to efficiently discriminate tumour patients from non-tumour patients. We then validated the results using mass
spectrometry and biochemical analysis of samples. For the 36 patients across three independent cohorts, the method identified
tumour patients with high sensitivity and identification as high as 100% (no false positives) with declared subjects at-risk, for
sporadic cancer onset, by intermediate values of PS. This assay could impact on cancer risk management, individualâs diagnosis
and/or help clarify risk in healthy populations
Climate-induced phenology shifts linked to range expansions in species with multiple reproductive cycles per year
Advances in phenology (the annual timing of speciesâ life-cycles) in response to climate change are generally viewed as bioindicators of climate change, but have not been considered as predictors of range expansions. Here, we show that phenology advances combine with the number of reproductive cycles per year (voltinism) to shape abundance and distribution trends in 130 species of British Lepidoptera, in response to ~0.5 °C spring-temperature warming between 1995 and 2014. Early adult emergence in warm years resulted in increased within- and between-year population growth for species with multiple reproductive cycles per year (n = 39 multivoltine species). By contrast, early emergence had neutral or negative consequences for species with a single annual reproductive cycle (n = 91 univoltine species), depending on habitat specialisation. We conclude that phenology advances facilitate polewards range expansions in species exhibiting plasticity for both phenology and voltinism, but may inhibit expansion by less flexible species
EB Ford revisited: assessing the long-term stability of wing-spot patterns and population genetic structure of the meadow brown butterfly on the Isles of Scilly
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Data files of wing spot sizes and AFLP genotypes available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.j7v42.Understanding selection in the wild remains a major aim of evolutionary ecology and work by Ford and colleagues on the meadow brown butterfly Maniola jurtina did much to ignite this agenda. A great deal of their work was conducted during the 1950s on the Isles of Scilly. They documented island-specific wing-spot patterns that remained consistent over about a decade, but patterns on some islands changed after environmental perturbation. It was suggested that these wing-spot patterns reflected island-specific selection and that there was little migration between islands. However, genetic studies to test the underlying assumption of restricted migration are lacking and it is also unknown whether the originally described wing-spot patterns have persisted over time. We therefore collected female butterflies from five of Ford's original study locations, including three large islands (St Mary's, St Martin's and Tresco) and two small islands (Tean and St Helen's). Wing-spot patterns had not changed appreciably over time on three of the islands (two large and one small), but were significantly different on the other two. Furthermore, analysis of 176 amplified fragment length polymorphisms revealed significant genome-wide differentiation among the five islands. Our findings are consistent with Ford's conclusions that despite the close proximity of these islands, there is restricted gene flow among them.Heredity advance online publication, 2 November 2016; doi:10.1038/hdy.2016.94.We thank the Genetics Society for a fieldwork grant (to DJH) that funded the collection trip and DJH thanks Mike Johnson for sparking interest in this area. SWB is supported by the Australian Research Council and a Ramsay Fellowship, NW by a Royal Society Wolfson Fellowship and NERC and DJH by the Leverhulme Trust
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