Ca-ATPase activity and protein composition of sarcoplasmic reticulum membranes isolated from skeletal muscles of typical hibernator, the ground squirrel Spermophilus undulatus

Ca-ATPase activity in sarcoplasmic reticulum (SR) membranes isolated from skeletal muscles of the typical hibernator, the ground squirrel Spermophilus undulatus, is about 2-fold lower than that in SR membranes of rats and rabbits and is further decreased 2-fold during hibernation. The use of carbocyanine anionic dye Stains-All has revealed that Ca-binding proteins of SR membranes, histidine-rich Ca-binding protein and sarcalumenin, in ground squirrel, rat, and rabbit SR have different electrophoretic mobility corresponding to apparent molecular masses 165, 155, and 170 kDa and 130, 145, and 160 kDa, respectively; the electrophoretic mobility of calsequestrin (63 kDa) is the same in all preparations. The content of these Ca-binding proteins in SR membranes of the ground squirrels is decreased 3–4 fold and the content of 55, 30, and 22 kDa proteins is significantly increased during hibernation

Continuous-Time Quantum Monte Carlo Approach to Singlet-Triplet Kondo Systems

Dynamical properties are studied numerically for a variant of the Kondo model with singlet and triplet crystalline electric field (CEF) levels where Kondo and CEF singlets compete for the ground state. Using the continuous-time quantum Monte Carlo method, we derive the $t$-matrix of conduction electrons and dynamical susceptibilities of local electrons without encountering the negative sign problem. When the CEF splitting is comparable to the Kondo temperature, the dynamical response has only a quasi-elastic peak. Nevertheless, the local single-particle spectrum shows an energy gap in strong contrast with the ordinary Kondo model.Comment: 9 pages, 10 figure

Molecular evolution of Adh and LEAFY and the phylogenetic utility of their introns in Pyrus (Rosaceae)

<p>Abstract</p> <p>Background</p> <p>The genus <it>Pyrus </it>belongs to the tribe Pyreae (the former subfamily Maloideae) of the family Rosaceae, and includes one of the most important commercial fruit crops, pear. The phylogeny of <it>Pyrus </it>has not been definitively reconstructed. In our previous efforts, the internal transcribed spacer region (ITS) revealed a poorly resolved phylogeny due to non-concerted evolution of nrDNA arrays. Therefore, introns of low copy nuclear genes (LCNG) are explored here for improved resolution. However, paralogs and lineage sorting are still two challenges for applying LCNGs in phylogenetic studies, and at least two independent nuclear loci should be compared. In this work the second intron of <it>LEAFY </it>and the alcohol dehydrogenase gene (<it>Adh</it>) were selected to investigate their molecular evolution and phylogenetic utility.</p> <p>Results</p> <p>DNA sequence analyses revealed a complex ortholog and paralog structure of <it>Adh </it>genes in <it>Pyrus </it>and <it>Malus</it>, the pears and apples. Comparisons between sequences from RT-PCR and genomic PCR indicate that some <it>Adh </it>homologs are putatively nonfunctional. A partial region of <it>Adh1 </it>was sequenced for 18 <it>Pyrus </it>species and three subparalogs representing <it>Adh1-1 </it>were identified. These led to poorly resolved phylogenies due to low sequence divergence and the inclusion of putative recombinants. For the second intron of <it>LEAFY</it>, multiple inparalogs were discovered for both <it>LFY1int2 </it>and <it>LFY2int2</it>. <it>LFY1int2 </it>is inadequate for phylogenetic analysis due to lineage sorting of two inparalogs. <it>LFY2int2-N</it>, however, showed a relatively high sequence divergence and led to the best-resolved phylogeny. This study documents the coexistence of outparalogs and inparalogs, and lineage sorting of these paralogs and orthologous copies. It reveals putative recombinants that can lead to incorrect phylogenetic inferences, and presents an improved phylogenetic resolution of <it>Pyrus </it>using <it>LFY2int2-N</it>.</p> <p>Conclusions</p> <p>Our study represents the first phylogenetic analyses based on LCNGs in <it>Pyrus</it>. Ancient and recent duplications lead to a complex structure of <it>Adh </it>outparalogs and inparalogs in <it>Pyrus </it>and <it>Malus</it>, resulting in neofunctionalization, nonfunctionalization and possible subfunctionalization. Among all investigated orthologs, <it>LFY2int2-N </it>is the best nuclear marker for phylogenetic reconstruction of <it>Pyrus </it>due to suitable sequence divergence and the absence of lineage sorting.</p

Development of an Early Warning Fire Detection System using Correlation Spectroscopy

Combustion byproducts are numerous. A few examples of the gaseous byproducts include carbon dioxide, carbon monoxide, hydrogen chloride, hydrogen cyanide and ammonia. For detecting these chemical species, classic absorption spectroscopy has been used for many decades, but the sensitivity of steady-state methods is often unsuitable for the detection of trace compounds at the low levels (parts per million to parts per billion) appropriate for scientific purposes. This is particularly so for monitoring equipment, which must be compact and cost-effective, and which is often subjected to shock, vibration, and other environmental effects that can severely degrade the performance of high-sensitivity spectrometers in an aircraft. Steady-state techniques also suffer from a lack of specificity; the deconvolution of the spectra of complex mixtures is a laborious and error prone process. These problems are exacerbated in remote fiber-optic monitoring where, for practical reasons, the fundamental absorbance region of the spectrum (often between 3 and 8 microns) is inaccessible, and the low-strength, closely spaced, near-infrared overtone absorbance bands must be used. We circumvented these challenges by employing correlation spectroscopy, a variation of modulation spectroscopy

How can Infra-Red Excitation Both Accelerate and Slow Charge Transfer in the Same Molecule?

A UV-IR-Vis 3-pulse study of infra-red induced changes to electron transfer (ET) rates in a donor-bridge-acceptor species finds that charge-separation rates are slowed, while charge-recombination rates are accelerated as a result of IR excitation during the reaction. We explore the underpinning mechanisms for this behavior, studying IR-induced changes to the donor-acceptor coupling, to the validity of the Condon approximation, and to the reaction coordinate distribution. We find that the dominant IR-induced rate effects in the species studied arise from changes to the density of states in the Marcus curve crossing region. That is, IR perturbation changes the probability of accessing the activated complex for the ET reactions. IR excitation diminishes the population of the activated complex for forward (activationless) ET, thus slowing the rate. However, IR excitation increases the population of the activated complex for (highly activated) charge recombination ET, thus accelerating the charge recombination rate

Hexamermis paranaense new species (Nematoda, Mermithidae): a parasite of Diloboderus abderus (Coleoptera, Scarabaeidae) in Argentina Hexamermis paranaense sp. nov. (Nematoda, Mermithidae): parasito de Diloboderus abderus (Coleoptera, Scarabaeidae) en Argentina

A new species, Hexamermis paranaense n. sp. (Nematoda, Mermithidae), a parasite of larvae of Diloboderus abderus Sturm, 1826 (Coleoptera, Scarabaeidae) is described and illustrated. This new species is characterized by amphids small, amphidial opening pocket-shaped, the anterior portion of the vagina muscularized and slightly protruding with a descending branch forming a loop before joining the uterus, and three rows of genital papillae: the ventrolateral divided in two rows with eight papillae in the outer row and with six papillae in the inner one; the ventral row with four pairs and one single preanal papillae, and with two pairs, a triplete, one pair, a single and one pair postanal papillae.<br>Una nueva especie, Hexamermis paranaense sp. nov. (Nematoda, Mermithidae), parásito de larvas del gusano blanco, Diloboderus abderus Sturm, 1826 (Coleoptera, Scarabaeidae), se describe e ilustra. Esta nueva especie se caracteriza por poseer anfidos pequeños, con la apertura en forma de bolsillo, parte anterior de la vagina muscular, con una rama que desciende y forma un lazo antes de la conexión al útero, tres hileras de papilas genitales: la hilera de posición ventro-lateral dividida en dos hileras con ocho papilas en la hilera externa y con seis papilas en la interna; la hilera ventral con una papila, seguida de cuatro pares, todas en posición preanal y dos pares, interrumpidos por tres papilas, seguida de un par, una simple, y un par, todas de posición postanal