Patterns of differential introgression in a salamander hybrid zone: inferences from genetic data and ecological niche modelling

Hybrid zones have yielded considerable insight into many evolutionary processes, including speciation and the maintenance of species boundaries. Presented here are analyses from a hybrid zone that occurs among three salamanders – Plethodon jordani , Plethodon metcalfi and Plethodon teyahalee – from the southern Appalachian Mountains. Using a novel statistical approach for analysis of non-clinal, multispecies hybrid zones, we examined spatial patterns of variation at four markers: single-nucleotide polymorphisms (SNPs) located in the mtDNA ND2 gene and the nuclear DNA ILF3 gene, and the morphological markers of red cheek pigmentation and white flecks. Concordance of the ILF3 marker and both morphological markers across four transects is observed. In three of the four transects, however, the pattern of mtDNA is discordant from all other markers, with a higher representation of P. metcalfi mtDNA in the northern and lower elevation localities than is expected given the ILF3 marker and morphology. To explore whether climate plays a role in the position of the hybrid zone, we created ecological niche models for P. jordani and P. metcalfi . Modelling results suggest that hybrid zone position is not determined by steep gradients in climatic suitability for either species. Instead, the hybrid zone lies in a climatically homogenous region that is broadly suitable for both P. jordani and P. metcalfi . We discuss various selective (natural selection associated with climate) and behavioural processes (sex-biased dispersal, asymmetric reproductive isolation) that might explain the discordance in the extent to which mtDNA and nuclear DNA and colour-pattern traits have moved across this hybrid zone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79135/1/j.1365-294X.2010.04796.x.pd

Багатогранна постать Івана Яковича Горбачевського

Introduction. Ivan Horbachevsky, native of the Ternopil region, is an outstanding figure in the Ukrainian history. Despite the fact that he had spent almost all his life in the foreign land, he was the faithful son of his Motherland. Ivan Horbachevsky was the first ethnic Ukrainian, who was appointed the health minister in the government of the Austro-Hungarian Empire. The name of Ivan Horbachevsky was being forgotten for a long time inequitably, even though his figure has high historical importance not only forGalicia, but also for wholeUkraine. It should be underlined, that his name has the same significance for Ukrainians as the famous names of Ivan Franko and Solomia Krushelnytska. Taking into account Horbachevsky’s contibutions to our country, in 1992 Cabinet of Ministers of Ukraine took the decision to give the name of this great scientist to the Ternopil Medical Institute. And in this year I. HorbachevskyTernopilStateMedicalUniversity celebrates its 60th anniversary.The aim of the study – to highlight scientific achievements and outline the main milestones in the life of such outstanding person, as Ivan Horbachevsky. This will be the invaluable gift for both present and future generations.Conclusions. The life of Ivan Horbachevsky could be an example for all of us, for all contemporaries, and his scientific contributions will be alive forever and will be continued in the numerous works of his followers. No doubt that every scientist and student of the institution should not only know and remember him, but also followed working and citizenship position of our great compatriot Ivan Horbachevsky.Вступление. Иван Яковлевич Горбачевский, уроженец Тернопольской земли, является неординарной фигурой в украинской истории, ведь, проведя практически всю свою жизнь на чужбине, он навеки остался верным сыном своего Отечества. Иван Яковлевич был первым этническим украинцем, которого назначили министром здравоохранения в правительстве Австро-Венгерской империи. Это имя долгое время оставалось несправедливо забытым, хотя его фигура по исторической значимости для Галичины в том числе и для Украины в целом не уступает знаменитым Ивану Франко и Соломии Крушельницкой. Несмотря на немалые заслуги перед Родиной, имя знаменитого ученого увековечено в названии Тернопольского медицинского института в1992 г. по решению Кабинета Министров Украины. А именно в этом году Тернопольский государственный медицинский университет имени Ивана Яковлевича Горбачевского отметил свое 60-летие.Цель исследования – осветить научные достижения и наметить основные вехи становления такой величественной личности, как Иван Яковлевич Горбачевский, что является неоценимым подарком как сегодняшнему, так и будущему поколению.Выводы. Жизненный путь Ивана Яковлевича Горбачевского является образцом для подражания современниками, а его научные достижения навеки остаются с нами и продолжают свою жизнь в многочисленных трудах последователей. Без сомнения, каждый ученый и студент учебного заведения должен не только помнить, но и подражать как в трудовой, так и в гражданской позиции нашего великого земляка Ивана Яковлевича Горбачевского.Вступ. Іван Якович Горбачевський, уродженець Тернопільської землі, є неординарною постаттю в українській історії, адже, провівши практично все своє життя на чужині, він навіки залишився вірним сином своєї Вітчизни. Іван Якович був першим етнічним українцем, якого призначили міністром охорони здоров’я в уряді Австро-Угорської імперії. Це ім’я тривалий час залишалося несправедливо забутим, хоча його постать за історичною значимістю для Галичини зокрема і для України загалом не поступається славетним Івану Франкові та Соломії Крушельницькій. Зважаючи на чималі заслуги перед Батьківщиною, ім’я славетного вченого увіковічено у назві Тернопільського медичного інституту в 1992 р. за рішенням Кабінету Міністрів України. А саме в цьому році Тернопільський державний медичний університет імені Івана Яковича Горбачевського відзначив своє 60-річчя. Мета дослідження – висвітлити науковий доробок та окреслити основні віхи становлення такої величної особистості, як Іван Якович Горбачевський, що є неоціненним дарунком як теперішньому, так і майбутньому поколінню.Висновки. Життєвий шлях Івана Яковича Горбачевського є взірцем для наслідування сучасниками, а його наукові досягнення навіки залишаються з нами і продовжують своє життя в численних працях послідовників. Без сумніву, кожен науковець і студент навчального закладу повинен не лише пам’ятати, але й наслідувати як у трудовій, так і в громадянській позиції нашого великого земляка Івана Яковича Горбачевського.

Viewpoint on Emv2, the onlhy endogenous ecotropic murine leukemia virus of C57BL/6 mice

Here I comment on the articles by Lee and colleagues (Retrovirology 2011, 8:82) and Lee and Cho (Retrovirology 2012, 9:23) dealing with an endogenous ecotropic mouse leukemia virus found in C57BL mice

Effect of neutrophil depletion on gelatinase expression, edema formation and hemorrhagic transformation after focal ischemic stroke

BACKGROUND: While gelatinase (MMP-2 and -9) activity is increased after focal ischemia/reperfusion injury in the brain, the relative contribution of neutrophils to the MMP activity and to the development of hemorrhagic transformation remains unknown. RESULTS: Anti-PMN treatment caused successful depletion of neutrophils in treated animals. There was no difference in either infarct volume or hemorrhage between control and PMN depleted animals. While there were significant increases in gelatinase (MMP-2 and MMP-9) expression and activity and edema formation associated with ischemia, neutrophil depletion failed to cause any change. CONCLUSION: The main finding of this study is that, in the absence of circulating neutrophils, MMP-2 and MMP-9 expression and activity are still up-regulated following focal cerebral ischemia. Additionally, neutrophil depletion had no influence on indicators of ischemic brain damage including edema, hemorrhage, and infarct size. These findings indicate that, at least acutely, neutrophils are not a significant contributor of gelatinase activity associated with acute neurovascular damage after stroke

A Possible Constraint on Regional Precipitation Intensity Changes under Global Warming

Changes in daily precipitation versus intensity under a global warming scenario in two regional climate simulations of the United States show a well-recognized feature of more intense precipitation. More important, by resolving the precipitation intensity spectrum, the changes show a relatively simple pattern for nearly all regions and seasons examined whereby nearly all high-intensity daily precipitation contributes a larger fraction of the total precipitation, and nearly all low-intensity precipitation contributes a reduced fraction. The percentile separating relative decrease from relative increase occurs around the 70th percentile of cumulative precipitation, irrespective of the governing precipitation processes or which model produced the simulation. Changes in normalized distributions display these features much more consistently than distribution changes without normalization. Further analysis suggests that this consistent response in precipitation intensity may be a consequence of the intensity spectrum’s adherence to a gamma distribution. Under the gamma distribution, when the total precipitation or number of precipitation days changes, there is a single transition between precipitation rates that contribute relatively more to the total and rates that contribute relatively less. The behavior is roughly the same as the results of the numerical models and is insensitive to characteristics of the baseline climate, such as average precipitation, frequency of rain days, and the shape parameter of the precipitation’s gamma distribution. Changes in the normalized precipitation distribution give a more consistent constraint on how precipitation intensity may change when climate changes than do changes in the nonnormalized distribution. The analysis does not apply to extreme precipitation for which the theory of statistical extremes more likely provides the appropriate description

Katanin localization requires triplet microtubules in Chlamydomonas reinhardtii

Centrioles and basal bodies are essential for a variety of cellular processes that include the recruitment of proteins to these structures for both centrosomal and ciliary function. This recruitment is compromised when centriole/basal body assembly is defective. Mutations that cause basal body assembly defects confer supersensitivity to Taxol. These include bld2, bld10, bld12, uni3, vfl1, vfl2, and vfl3. Flagellar motility mutants do not confer sensitivity with the exception of mutations in the p60 (pf19) and p80 (pf15) subunits of the microtubule severing protein katanin. We have identified additional pf15 and bld2 (ε-tubulin) alleles in screens for Taxol sensitivity. Null pf15 and bld2 alleles are viable and are not essential genes in Chlamydomonas. Analysis of double mutant strains with the pf15-3 and bld2-6 null alleles suggests that basal bodies in Chlamydomonas may recruit additional proteins beyond katanin that affect spindle microtubule stability. The bld2-5 allele is a hypomorphic allele and its phenotype is modulated by nutritional cues. Basal bodies in bld2-5 cells are missing proximal ends. The basal body mutants show aberrant localization of an epitope-tagged p80 subunit of katanin. Unlike IFT proteins, katanin p80 does not localize to the transition fibers of the basal bodies based on an analysis of the uni1 mutant as well as the lack of colocalization of katanin p80 with IFT74. We suggest that the triplet microtubules are likely to play a key role in katanin p80 recruitment to the basal body of Chlamydomonas rather than the transition fibers that are needed for IFT localization

Multifractals of Normalized First Passage Time in Sierpinski Gasket

The multifractal behavior of the normalized first passage time is investigated on the two dimensional Sierpinski gasket with both absorbing and reflecting barriers. The normalized first passage time for Sinai model and the logistic model to arrive at the absorbing barrier after starting from an arbitrary site, especially obtained by the calculation via the Monte Carlo simulation, is discussed numerically. The generalized dimension and the spectrum are also estimated from the distribution of the normalized first passage time, and compared with the results on the finitely square lattice.Comment: 10 pages, Latex, with 3 figures and 1 table. to be published in J. Phys. Soc. Jpn. Vol.67(1998

TISs-ST: a web server to evaluate polymorphic translation initiation sites and their reflections on the secretory targets

<p>Abstract</p> <p>Background</p> <p>The nucleotide sequence flanking the translation initiation codon (start codon context) affects the translational efficiency of eukaryotic mRNAs, and may indicate the presence of an alternative translation initiation site (TIS) to produce proteins with different properties. Multi-targeting may reflect the translational variability of these other protein forms. In this paper we present a web server that performs computations to investigate the usage of alternative translation initiation sites for the synthesis of new protein variants that might have different functions.</p> <p>Results</p> <p>An efficient web-based tool entitled TISs-ST (Translation Initiation Sites and Secretory Targets) evaluates putative translation initiation sites and indicates the prediction of a signal peptide of the protein encoded from this site. The TISs-ST web server is freely available to both academic and commercial users and can be accessed at <url>http://ipe.cbmeg.unicamp.br/pub/TISs-ST</url>.</p> <p>Conclusion</p> <p>The program can be used to evaluate alternative translation initiation site consensus with user-specified sequences, based on their composition or on many position weight matrix models. TISs-ST provides analytical and visualization tools for evaluating the periodic frequency, the consensus pattern and the total information content of a sequence data set. A search option allows for the identification of signal peptides from predicted proteins using the PrediSi software.</p