139 research outputs found
Closely related dermatophyte species produce different patterns of secreted proteins
Dermatophytes are the most common infectious agents responsible for superficial mycosis in humans and animals. Various species in this group of fungi show overlapping characteristics. We investigated the possibility that closely related dermatophyte species with different behaviours secrete distinct proteins when grown in the same culture medium. Protein patterns from culture filtrates of several strains of the same species were very similar. In contrast, secreted protein profiles from various species were different, and so a specific signature could be associated with each of the six analysed species. In particular, protein patterns were useful to distinguish Trichophyton tonsurans from Trichophyton equinum, which cannot be differentiated by ribosomal DNA sequencing. The secreted proteases Sub2, Sub6 and Sub7 of the subtilisin family, as well as Mep3 and Mep4 of the fungalisin family were identified. SUB6, SUB7, MEP3 and MEP4 genes were cloned and sequenced. Although the protein sequence of each protease was highly conserved across species, their level of secretion by the various species was not equivalent. These results suggest that a switch of habitat could be related to a differential expression of genes encoding homologous secreted protein
Infalling-Rotating Motion and Associated Chemical Change in the Envelope of IRAS 16293-2422 Source A Studied with ALMA
We have analyzed rotational spectral line emission of OCS, CH3OH, HCOOCH3,
and H2CS observed toward the low-mass Class 0 protostellar source IRAS
16293-2422 Source A at a sub-arcsecond resolution (~0".6 x 0".5) with ALMA.
Significant chemical differentiation is found at a 50 AU scale. The OCS line is
found to well trace the infalling-rotating envelope in this source. On the
other hand, the CH3OH and HCOOCH3 distributions are found to be concentrated
around the inner part of the infalling-rotating envelope. With a simple
ballistic model of the infalling-rotating envelope, the radius of the
centrifugal barrier (a half of the centrifugal radius) and the protostellar
mass are evaluated from the OCS data to be from 40 to 60 AU and from 0.5 to 1.0
Msun, respectively, assuming the inclination angle of the envelope/disk
structure to be 60 degrees (90 degrees for the edge-on configuration). Although
the protostellar mass is correlated with the inclination angle, the radius of
the centrifugal barrier is not. This is the first indication of the centrifugal
barrier of the infalling-rotating envelope in a hot corino source. CH3OH and
HCOOCH3 may be liberated from ice mantles due to weak accretion shocks around
the centrifugal barrier, and/or due to protostellar heating. The H2CS emission
seems to come from the disk component inside the centrifugal barrier in
addition to the envelope component. The centrifugal barrier plays a central
role not only in the formation of a rotationally-supported disk but also in the
chemical evolution from the envelope to the protoplanetary disk
Hot Corinos Chemical Diversity: Myth or Reality?
After almost 20 years of hunting, only about a dozen hot corinos, hot regions
enriched in interstellar complex organic molecules (iCOMs), are known. Of them,
many are binary systems with the two components showing drastically different
molecular spectra. Two obvious questions arise. Why are hot corinos so
difficult to find and why do their binary components seem chemically different?
The answer to both questions could be a high dust opacity that would hide the
molecular lines. To test this hypothesis, we observed methanol lines at
centimeter wavelengths, where dust opacity is negligible, using the Very Large
Array interferometer. We targeted the NGC 1333 IRAS 4A binary system, for which
one of the two components, 4A1, has a spectrum deprived of iCOMs lines when
observed at millimeter wavelengths, while the other component, 4A2, is very
rich in iCOMs. We found that centimeter methanol lines are similarly bright
toward 4A1 and 4A2. Their non-LTE analysis indicates gas density and
temperature ( cm and 100--190 K), methanol column
density ( cm) and extent (35 au in radius) similar in
4A1 and 4A2, proving that both are hot corinos. Furthermore, the comparison
with previous methanol line millimeter observations allows us to estimate the
optical depth of the dust in front of 4A1 and 4A2, respectively. The obtained
values explain the absence of iCOMs line emission toward 4A1 at millimeter
wavelengths and indicate that the abundances toward 4A2 are underestimated by
30\%. Therefore, centimeter observations are crucial for the correct
study of hot corinos, their census, and their molecular abundances.Comment: 9 pages, 3 figures, 2 Tables - Published in ApJ Letter
Parallel Tempering: Theory, Applications, and New Perspectives
We review the history of the parallel tempering simulation method. From its
origins in data analysis, the parallel tempering method has become a standard
workhorse of physiochemical simulations. We discuss the theory behind the
method and its various generalizations. We mention a selected set of the many
applications that have become possible with the introduction of parallel
tempering and we suggest several promising avenues for future research.Comment: 21 pages, 4 figure
The Protease Inhibitor Alpha-2-Macroglobuline-Like-1 Is the p170 Antigen Recognized by Paraneoplastic Pemphigus Autoantibodies in Human
Paraneoplastic pemphigus (PNP) is a devastating autoimmune blistering disease, involving mucocutaneous and internal organs, and associated with underlying neoplasms. PNP is characterized by the production of autoantibodies targeting proteins of the plakin and cadherin families involved in maintenance of cell architecture and tissue cohesion. Nevertheless, the identity of an antigen of Mr 170,000 (p170), thought to be critical in PNP pathogenesis, has remained unknown
BPAG1a and b Associate with EB1 and EB3 and Modulate Vesicular Transport, Golgi Apparatus Structure, and Cell Migration in C2.7 Myoblasts
BPAG1a and BPAG1b (BPAG1a/b) constitute two major isoforms encoded by the dystonin (Dst) gene and show homology with MACF1a and MACF1b. These proteins are members of the plakin family, giant multi-modular proteins able to connect the intermediate filament, microtubule and microfilament cytoskeletal networks with each other and to distinct cell membrane sites. They also serve as scaffolds for signaling proteins that modulate cytoskeletal dynamics. To gain better insights into the functions of BPAG1a/b, we further characterized their C-terminal region important for their interaction with microtubules and assessed the role of these isoforms in the cytoskeletal organization of C2.7 myoblast cells. Our results show that alternative splicing does not only occur at the 5âČ end of Dst and Macf1 pre-mRNAs, as previously reported, but also at their 3âČ end, resulting in expression of additional four mRNA variants of BPAG1 and MACF1. These isoform-specific C-tails were able to bundle microtubules and bound to both EB1 and EB3, two microtubule plus end proteins. In the C2.7 cell line, knockdown of BPAG1a/b had no major effect on the organization of the microtubule and microfilament networks, but negatively affected endocytosis and maintenance of the Golgi apparatus structure, which became dispersed. Finally, knockdown of BPAG1a/b caused a specific decrease in the directness of cell migration, but did not impair initial cell adhesion. These data provide novel insights into the complexity of alternative splicing of Dst pre-mRNAs and into the role of BPAG1a/b in vesicular transport, Golgi apparatus structure as well as in migration in C2.7 myoblasts
Kinematic and thermal evolution of the Moroccan rifted continental margin: Doukkala-High Atlas Transect
The Atlantic passive margin of Morocco developed during Mesozoic times in association with the opening of the Central Atlantic and the Alpine Tethys. Extensional basins formed along the future continental margin and in the Atlas rift system. In Alpine times, this system was inverted to form the High and Middle Atlas fold-and-thrust belts. To provide a quantitative kinematic analysis of the evolution of the rifted margin, we present a crustal section crossing the Atlantic margin in the region of the Doukkala Basin, the Meseta and the Atlas system. We construct a post-rift upper crustal section compensating for Tertiary to present vertical movements and horizontal deformations, and we conduct numerical modeling to test quantitative relations between amounts and distribution of thinning and related vertical movements. Rifting along the transect began in the Late Triassic and ended with the appearance of oceanic crust at 175 Ma. Subsidence, possibly related to crustal thinning, continued in the Atlas rift in the Middle Jurassic. The numerical models confirm that the margin experienced a polyphase rifting history. The lithosphere along the transect preserved some strength throughout rifting with the Effective Elastic Thickness corresponding to an isotherm of 450°C. A mid-crustal level of necking of 15 km characterized the pre-rift lithosphere. © 2010 by the American Geophysical Union
Dissecting the interaction of plakins with epidermal keratins: role of plakins C-terminal domains, type I keratins coil 1 and keratins quaternary structure
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