Five Minute Dog Feeder

In this article, the author explores music education counterforces, examining whether and how (a) federal and state education policies can better address the in-service needs of special area teachers, particularly music teachers, in the school setting; and (b) policy organizations in the music education profession (i.e., The National Association for Music Education, the National Association of Schools of Music, the College Music Society, the Society for Music Teacher Education, and the Music Education Research Council) might also address the inherent tensions between music education and schooling.     

The field-dependence of the solid-state photo-CIDNP effect in two states of heliobacterial reaction centers

The solid-state photo-CIDNP (photochemically induced dynamic nuclear polarization) effect is studied in photosynthetic reaction centers of Heliobacillus mobilis at different magnetic fields by ¹³C MAS (magic-angle spinning) NMR spectroscopy. Two active states of heliobacterial reaction centers are probed: an anaerobic preparation of heliochromatophores (“Braunstoff”, German for “brown substance”) as well as a preparation of cells after exposure to oxygen (“Grünstoff”, “green substance”). Braunstoff shows significant increase of enhanced absorptive (positive) signals toward lower magnetic fields, which is interpreted in terms of an enhanced differential relaxation (DR) mechanism. In Grünstoff, the signals remain emissive (negative) at two fields, confirming that the influence of the DR mechanism is comparably low.     

Application of Adaptive Cluster Sampling with a Data‐Driven Stopping Rule to Plant Disease Incidence

Plant pathologists need to manage plant diseases at low incidence levels. This needs to be performed efficiently in terms of precision, cost and time because most plant infections spread rapidly to other plants. Adaptive cluster sampling with a data‐driven stopping rule (ACS*) was proposed to control the final sample size and improve efficiency of the ordinary adaptive cluster sampling (ACS) when prior knowledge of population structure is not known. This study seeks to apply the ACS* design to plant diseases at various levels of clustering and incidences levels. Results from simulation study show that the ACS* is as efficient as the ordinary ACS design at low levels of disease incidence with highly clustered diseased plants and is an efficient design compared with simple random sampling (SRS) and ordinary ACS for some highly to less clustered diseased plants with moderate to higher levels of disease incidence.     

ABL/BCR gene variant with two-step mechanism: Unusual localization and rare/novel chromosomal rearrangements in CML patients

Aims: Variant translocations involving 9q, 22q and at least one additional genomic locus occur in 5-10% of the patients with chronic myeloid leukemia (CML). The mechanisms for the formation of these variant translocations are not fully characterized. Here we report CML cases presenting a variant translocation indicating two-step mechanism with rare/novel chromosomal rearrangement. Methods: Karyotype analysis was performed on metaphases obtained through short-term cultures of bone marrow and blood. Detection of BCR-ABL fusion gene was performed using dual-color dual-fusion (D-FISH) and extra signal (ES) translocation probes. BAC-FISH was also carried out. Results: In Patient 1, the third partner chromosome was der(11)(p15) with a 2F2G1R signal pattern, which is an unusual signal pattern with the two-step mechanism. Patients 2 and 3 showed typical positive (2F1G1R) signal pattern. In Patient 2, both the chromosome 22s were involved in variant formation. The second fusion was observed below the BCR gene of the second homologue. In Patient 3 the third chromosome was der(13)(q14). The fourth patient showed a variant pattern with BCR/ABL-ES probe involving der(X)(q13) region. Conclusion: The presence of different rearrangements of both 9q34 and 22q11 regions highlights the genetic heterogeneity of this subgroup of CML. In each case with variants, further studies with FISH, BAC-FISH or more advanced technique such as microarray should be performed. Future studies should be performed to confirm the presence of true breakpoint hot spots and assess their implications in CML with variant Ph.     

Characterization of the primary radical pair in reaction centers of Heliobacillus mobilis by 13C photo-CIDNP MAS NMR

Photochemically induced dynamic nuclear polarization (photo-CIDNP) has been observed in membrane fragments of heliobacterium Heliobacillus mobilis without further isolation by (13)C magic-angle spinning (MAS) solid-state NMR under continuous illumination with white light. In the (13)C photo-CIDNP MAS NMR spectra of heliobacterial membrane fragments, two sets of signals are observed, allowing characterization of the primary radical pair. One set, showing enhanced absorptive (positive) signals, arises from the BChl g donor, while the set of emissive (negative) signals is assigned to the 8(1)-hydroxy Chl a acceptor. Hence, under these sample conditions, both donor and acceptor sides are either monomeric or composed of identical cofactors. The occurrence of the differential relaxation (DR) mechanism suggests a donor triplet lifetime in the microsecond range. It appears that the occurrence of the solid-state photo-CIDNP effect is a general feature of primary radical pairs in natural photosynthesis.     

Logistic Proliferation of Cells in Scratch Assays is Delayed

Scratch assays are used to study how a population of cells re-colonises a vacant region on a two-dimensional substrate after a cell monolayer is scratched. These experiments are used in many applications including drug design for the treatment of cancer and chronic wounds. To provide insights into the mechanisms that drive scratch assays, solutions of continuum reaction–diffusion models have been calibrated to data from scratch assays. These models typically include a logistic source term to describe carrying capacity-limited proliferation; however, the choice of using a logistic source term is often made without examining whether it is valid. Here we study the proliferation of PC-3 prostate cancer cells in a scratch assay. All experimental results for the scratch assay are compared with equivalent results from a proliferation assay where the cell monolayer is not scratched. Visual inspection of the time evolution of the cell density away from the location of the scratch reveals a series of sigmoid curves that could be naively calibrated to the solution of the logistic growth model. However, careful analysis of the per capita growth rate as a function of density reveals several key differences between the proliferation of cells in scratch and proliferation assays. Our findings suggest that the logistic growth model is valid for the entire duration of the proliferation assay. On the other hand, guided by data, we suggest that there are two phases of proliferation in a scratch assay; at short time, we have a disturbance phase where proliferation is not logistic, and this is followed by a growth phase where proliferation appears to be logistic. These two phases are observed across a large number of experiments performed at different initial cell densities. Overall our study shows that simply calibrating the solution of a continuum model to a scratch assay might produce misleading parameter estimates, and this issue can be resolved by making a distinction between the disturbance and growth phases. Repeating our procedure for other scratch assays will provide insight into the roles of the disturbance and growth phases for different cell lines and scratch assays performed on different substrates.     

Differential gene expression in Giardia lamblia under oxidative stress: Significance in eukaryotic evolution

Giardia lamblia is a unicellular, early branching eukaryote causing giardiasis, one of the most common human enteric diseases. Giardia, a microaerophilic protozoan parasite has to build up mechanisms to protect themselves against oxidative stress within the human gut (oxygen concentration 60 μM) to establish its pathogenesis. G. lamblia is devoid of the conventional mechanisms of the oxidative stress management system, including superoxide dismutase, catalase, peroxidase, and glutathione cycling, which are present in most eukaryotes. NADH oxidase is a major component of the electron transport chain of G. lamblia, which in concurrence with disulfide reductase, protects oxygen-labile proteins such as pyruvate: ferredoxin oxidoreductase against oxidative stress by sustaining a reduced intracellular environment. It also contains the arginine dihydrolase pathway, which occurs in a number of anaerobic prokaryotes, includes substrate level phosphorylation and adequately active to make a major contribution to ATP production.     

Studies on the skull of the Indian sisorid catfish, Erethistes pussilus

The skull of Erethistes pussilus is described in detail. The general disposition of the bones corresponds to the siluroid pattern. Among the siluroid fishes, E. pussilus approaches the advanced forms in certain features such as obliteration of myodomic space, edentulous palate, absence of entopterygoids and supratemporals, intimate sutural articulation of posttemporals and complex vertebra with the cranium, diminished cranial cavity and loss of sutural articulation among the palatopterygoquadrate elements. In certain characters like the hyomandibula exclusively supported from the sphenotic, solitary hypohyal on each hyoid cornu, absence of interhyals, reduced orbits, edentulous vomer, small gape of mouth, toothless ectopterygoid and in the small number of branchiostegals, E. pussilus stands specialized alone among the catfishes. A diagnosis of the salient cranial characters of the fish is given and its relationship discussed.     

Trisomy 8 in leukemia: A GCRI experience

Trisomy of chromosome 8 is frequently reported in myeloid lineage disorders and also detected in lymphoid neoplasms as well as solid tumors suggesting its role in neoplastic progression in general. It is likely to be a disease-modulating secondary event with underlying cryptic aberrations as it has been frequently reported in addition to known abnormalities contributing to clinical heterogeneity and modifying prognosis. Here, we share our findings of trisomy 8 in leukemia patients referred for diagnostic and prognostic cytogenetic assessment. Total 60 cases of trisomy 8, as a sole anomaly or in addition to other chromosomal aberrations, were reported (January 2005-September 2008). Unstimulated bone marrow or blood samples were cultured, followed by GTG banding and karyotyping as per the ISCN 2005. Patients with +8 were chronic myeloid leukemia (CML) (36), acute myeloid leukemia (AML) (17), and acute lymphoblastic leukemia (ALL) (7). In 7 patients, trisomy 8 was the sole anomaly, whereas in 6 patients +8 was in addition to normal clone, in 47 patients, the +8 was in addition to t(9;22), t(15;17), and others, including 3 with tetrasomy 8. Only one patient showed constitutional +8. The present study will form the basis of further cumulative studies to correlate potential differential effects of various karyotypic anomalies on disease progression and survival following a therapeutic regime. To unravel the role of extra 8 chromosome, constitutional chromosomal analysis and uniparental disomy will be considered.     

Solution Structure of an ABC Collagen Heterotrimer Reveals a Single-register Helix Stabilized by Electrostatic Interactions

Collagen, known for its structural role in tissues and also for its participation in the regulation of homeostatic and pathological processes in mammals, is assembled from triple helices that can be either homotrimers or heterotrimers. High resolution structural information for natural collagens has been difficult to obtain because of their size and the heterogeneity of their native environment. For this reason, peptides that self-assemble into collagen-like triple helices are used to gain insight into the structure, stability, and biochemistry of this important protein family. Although many of the most common collagens in humans are heterotrimers, almost all studies of collagen helices have been on homotrimers. Here we report the first structure of a collagen heterotrimer. Our structure, obtained by solution NMR, highlights the role of electrostatic interactions as stabilizing factors within the triple helical folding motif. This addresses an issue that has been actively researched because of the predominance of charged residues in the collagen family. We also find that it is possible to selectively form a collagen heterotrimer with a well defined composition and register of the peptide chains within the helix, based on information encoded solely in the collagenous domain. Globular domains are implicated in determining the composition of several collagen types, but it is unclear what their role in controlling register may be. We show that is possible to design peptides that not only selectively choose a composition but also a specific register without the assistance of other protein constructs. This mechanism may be used in nature as well.Collagens constitute an important structural protein family. They are found in the extracellular matrix and undergo a hierarchical self-assembly into large supramolecular structures with specific morphologies carefully crafted by nature to fulfill diverse structural and functional roles in a wide variety of tissues. In total, there are 28 known isoforms of collagen in humans arranged in a variety of structures and in a wide range of tissues. The feature defining this protein family is the presence of domains with uninterrupted Xaa-Yaa-Gly sequence repeats. These domains adopt a left-handed polyproline type II conformation because of the predominance of proline in the X position and hydroxyproline (Hyp = O), a post-translationally modified amino acid with a hydroxyl group on the γ-carbon of the proline side chain, in the Y position. Three such domains associate to form tightly packed right-handed triple helices in a folding motif commonly known as the collagen triple helix.Collagens are also implicated in pivotal homeostatic events in mammals such as the production of new vascular tissue and pathological conditions such as cancer metastasis (1). These processes are notoriously governed by interactions at the molecular level between cell surface proteins and the collagen triple helix and not by the morphology of the collagen aggregates (2, 3). Thus, an understanding of the collagen molecule and its interactions with other proteins at the atomic level has been actively pursued. However, because of its complex hierarchical self-assembly, and the scale of the resulting supramolecular structures, it is difficult to obtain information at atomic resolution for collagenous proteins (4). An approach developed to overcome this limitation is the use of short model peptides that adopt a triple helical fold (5). Such peptides have been used to study the structure (6, 7), folding (8), and dynamics (9) of the triple helix. These peptides have been shown to retain the biochemical properties of the higher assemblies found in their natural counterparts, binding to cell surface proteins such as integrins (10).Most of the studies performed on collagen mimetic peptides utilize triple helices with three identical chains called homotrimers (8, 11–13). Such systems are good models for some types of collagen, like type II. However, many of the most abundant types of collagen such as type I, IV, and IX are heterotrimeric species containing two (AAB) or three (ABC) different chains. Recently we introduced a new method to prepare heterotrimeric collagen like triple helices via noncovalent interactions (14–16). These systems have been primarily characterized through CD spectroscopy, which is a good indicator for the fold and stability of the peptides but lacks the ability to give detailed structural information. There are few studies available in the literature that utilize NMR to examine collagen heterotrimers; however, none of them use the technique to examine the structures of the assemblies in detail (17–20), and none result in a complete structural determination.A system of particular interest is composed of three peptides, (Pro-Lys-Gly)₁₀, (Asp-Hyp-Gly)₁₀, and (Pro-Hyp-Gly)₁₀, which we abbreviate K, D, and O respectively. Upon mixing and annealing of the peptides, CD studies indicate that an ABC triple helix with a surprisingly high thermal stability is formed (16). We hypothesized that the high thermal stability of these systems comes from the formation of charge pairs between lysine and aspartic acid. Homotrimeric model peptides that contain the sequence KGD, which occurs both in mammalian collagen (21) and bacterial collagen-like proteins (22), apparently also use this charge pairing. However, no structural information has been available to confirm the nature of the interactions.Here we study the K·D·O system using two- and three-dimensional NMR techniques to determine the composition and fold of the components of an annealed mixture of these three peptides. Also, for the first time, we are able to study the register or relative stagger of the peptide chains in the triple helix. In a collagen triple helix, the chains assemble staggered by one amino acid, so that there is always a glycine residue in every cross-section of the helix taken perpendicular to the helical axis. This allows the peptide chains to pack tightly while avoiding steric clashes in the center of the assembly. Depending on the nature of the leading, middle, and trailing chain, a total of six different assemblies, or registers, are possible for an ABC system (Fig. 1). Given the high thermal stability of the system, which allows for the recording of high quality NMR spectra, we found that our peptides preferentially populate one register, and using samples with strategically placed isotopically labeled amino acids, we are able to determine which one. Furthermore, we are able to obtain the first structure of a collagen triple helix in solution and give direct evidence of ionic hydrogen bonds as a stabilizing factor within the triple helical folding motif.Open in a separate windowFIGURE 1.Schematic N-terminal representation of the six possible registers for the heterotrimeric triple helix. The difference in the sequence is highlighted below each representation, where the position of glycine residues is marked by colored spheres.