bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies using a fluorescent analogue of kinesin
Authors: Marya P. K. , Fraylich P. E. , Flood C. R. , Rao R. , Eagles P. A. M. 
Published: May 2013

ABSTRACT
The microtubule motor protein kinesin has been conjugated with 5-iodoacetamido fluorescein (5-IAF). The analogue, AF-kinesin, supports organelle motility and the movement of microtubules.
Differential regulation of vertebrate myosins I and II
Authors: Collins Kathleen , Matsudaira Paul 
Published: May 2013

ABSTRACT
Cell motility events require movement of the cytoskeleton. Actin-based movement is catalyzed by the mechanoenzyme myosin, which translocates toward the barbed end of actin filaments in an ATP-dependent fashion. There are two subclasses of myosin with different structures and functions: conventional filamentous myosin (myosin II) and monomeric myosin I. Vertebrate non-muscle myosins I and II function as similar actin motors in vitro, catalyzing virtually identical actin-activated MgATP hydrolysis and motility. The functional diversification of these two enzymes results from their differential regulation. Calcium and tropomyosin, which activate the MgATP hydrolysis and motility of vertebrate non-skeletal muscle myosin II proteins, inhibit vertebrate (brush border) myosin I. The activities and regulation of brush border myosin I provide insight into conserved and unique features of the myosin mechanoenzymes and suggest how the functions of myosins I and II are divided in vertebrate cells. Brush border myosin I as an enzyme also contributes to our understanding of the molecular mechanism of motility.
The influence of pressure on actin and myosin interactions in solution and in single muscle fibres
Authors: Geeves M. A. 
Published: May 2013

ABSTRACT
Studies of the molecular mechanism of motile activity require the capacity to examine the properties of individual, isolated molecular components and the properties of these same molecular components in the organised system. Pressure perturbation is one method which can be applied to motile systems at different levels of organisation. We show here that pressure perturbs a specific interaction between actin and myosin in solution and also perturbs the cycling crossbridge in a contracting muscle.
Involvement of neurofilaments in the radial growth of axons
Authors: Cleveland Don W. , Monteiro Mervyn J. , Wong Philip C. , Gill Steven R. , Gearhart John D. , Hoffman Paul N. 
Published: May 2013

ABSTRACT
The control of radial growth of axons is of functional importance because caliber is a principal determinant of conduction velocity in myelinated nerve fibers. Neurofilaments, the major cytoskeletal protein in myelinated nerves, appear to be intrinsic determinants of caliber. Evidence supporting this derives first from the linear relationship between neurofilament content and axonal diameter. Further, following distal axonal injury in a peripheral nerve, caliber is reduced in the proximal axonal stumps. This reduction in caliber is itself due to selective suppression of neurofilament gene expression, thereby leading to lower levels of newly synthesized neurofilament subunits transported into the axon and a consequent decrease in axonal neurofilament content. To demonstrate directly the physiological consequence of altering normal neurofilament accumulation, we have elevated neurofilament expression by introducing additional genes into transgenic mice. The clear result is that increases in NF-L content alone are not sufficient to increase axonal caliber. To test the consequence of disruption of normal filament accumulation, we have identified dominant assembly-disrupting mutants in NF-L and NF-M and have used these to produce transgenic animals in which neurofilament assembly should be disrupted.
Growth cone transduction: Go and GAP-43
Authors: Strittmatter Stephen M. , Valenzuela Dario , Vartanian Timothy , Sudo Yoshiaki , Zuber Mauricio X. , Fishman Mark C. 
Published: May 2013

ABSTRACT
The neuronal growth cone plays a crucial role in forming the complex brain architecture achieved during development, and similar nerve terminal mechanisms may operate to modify synaptic structure during adulthood. The growth cone leads the elongating axon towards appropriate synaptic targets by altering motility in response to a variety of extracellular signals. Independently of extrinsic clues, neurons mainfest intrinsic control of their growth and form (Banker and Cowan, 1979). Hence, there must be intracellular proteins which control nerve cell shape, so-called ‘plasticity’ or ‘growth’ genes. GAP-43 may be such a molecule (Skene and Willard, 1981; Benowitz and Lewis, 1983). For example, GAP-43 is localized to the growth cone membrane (Meiri et al. 1986; Skene et al. 1986) and can enhance filopodial formation even in nonneuronal cells (Zuber et al. 1989a). It includes a small region at the amino terminus for membrane association and perhaps growth cone targeting (Zuber et al. 1989b, Liu et al. 1991).
We have found that Go, a member of the G protein family that links receptors and second messengers, is the major non-cytoskeletal protein in the growth cone membrane (Strittmatter et al. 1990). Double staining immunohistochemistry for GAP-43 and Go shows that the distributions of the two proteins are quite similar. Purified GAP-43 regulates the activity of purified Go (Strittmatter et al. 1990), a surprising observation since GAP-43 is an intracellular protein. We have compared the mechanism of GAP-43 activation of Go with that of G protein-linked receptors. GAP-43 resembles receptor activation in that both serve primarily to increase the rate of dissociation of bound GDP, with consequent increase in GTPγS binding and GTPase activity. Neither affects the intrinsic rate of hydrolysis of bound GTP by Go. They differ, however, in that pertussis toxin blocks interaction of the receptor with Go, but not that of GAP-43. Furthermore, whereas GAP-43 activates both isolated αo subunits and α β γ trimers, receptors require the presence of the αγ subunits. Thus like receptors, GAP-43 is a guanine nucleotide release protein, but of a novel class. The interactions between Go and GAP-43 suggest that Go plays a pivotal role in growth cone function, coordinating the effects of both extracellular signals and intracellular growth proteins.
SWI6 is a regulatory subunit of two different cell cycle START-dependent transcription factors in Saccharomyces cerevisiae
Authors: Moll Thomas , Dirick LÉOn , Auer Erbert , Bonkovsky Josh , Nasmyth Kim 
Published: May 2013

ABSTRACT
Most genes involved in DNA replication in the yeast Saccharomyces cerevisiae are transcribed transiently during late Gi as cells undergo START. Their promoters all contain one or more versions of an 8-base pair motif (ACGCGTNA) called the Mlul cell cycle box (MCB). MCBs have been shown to be both necessary and sufficient for the late Gi-specific transcription of the TMP1 thymidylate synthase and POLI DNA polymerase genes. A different late Gi-specific transcription element called the SCB (CACGAAAA) is bound by a factor containing the SWI4 and SWI6 proteins. We describe here the formation in vitro of complexes on TMP1 MCBs that contain the SWI6 protein and, we suggest, a 120 kDa protein that is distinct from SWI4. Transcription due to SCBs and MCBs occurs in the absence of SWI6 but it is no longer correctly cell cycle regulated. We suggest that SWI6 is an essential regulatory subunit of two different START-dependent transcription factors. One factor (SBF) contains SWI4 and binds to SCBs whereas the other (MBF) contains p120 and binds MCBs.
Functional conservation of nematode and vertebrate myogenic regulatory factors
Authors: Krause Michael , Fire Andrew , White-Harrison Susan , Weintraub Harold , Tapscott Stephen 
Published: May 2013

ABSTRACT
The Caenorhabditis elegans protein, CeMyoD, is related to the vertebrate myogenic regulatory factors MyoD, myogenin, MRF-4 and Myf-5. Like its vertebrate counterparts, CeMyoD accumulates in the nucleus of striated muscle cells prior to the onset of terminal differentiation. CeMyoD also shares functional similarities with the vertebrate myogenic regulatory factors. Viral LTR driven expression of CeMyoD in mouse 10T1/2 cells can convert this cell line into myoblasts as well as efficiently Zrans-activate mouse muscle-specific promoters. Furthermore, mouse MyoD expression can activate a CeMyoD-P-galactosidase reporter construct in a 10T1/2 co-transfection assay.
Molecular sorting in polarized and non-polarized cells: common problems, common solutions
Authors: Mellman Ira , Yamamoto Ellen , Whitney J. Andrew , Kim Min , Hunziker Walter , Matter Karl 
Published: May 2013

ABSTRACT
We have been interested in determining how epithelial cells generate and maintain their characteristically polarized distributions of membrane proteins. Our efforts to date strongly indicate that the polarized transport in MDCK cells may be due to a set of discrete targeting determinants often found on a membrane protein’s cytoplasmic domain. Surprisingly, these determinants are widely distributed and are not specific to proteins expressed in polarized cells. They also appear to function in controlling polarized transport along both the biosynthetic and the endocytic (or tran-scytotic) pathways. Signals for basolateral transport have been characterized and, like the cytoplasmic domain signal used by plasma membrane receptors for accumulation at clathrin-coated pits, they often involve a critical tyrosine residue. Although the basolateral and coated pit signals may also be co-linear, they are not identical. The basolateral and apical transport determinants are also hierarchically arranged. Although a single protein may contain one or more signals specifying basolateral transport, inactivation of these signals appears to reveal a determinant that directs efficient apical transport. Given that the sequence determinants responsible for polarized transport are not restricted to epithelial cells and are related to determinants commonly utilized in all cells, it is possible that non-polar-ized cells contain cognate apical and basolateral pathways that are responsible for ‘constitutive’ transport from the Golgi to the plasma membrane. The presence of two cognate pathways might confer a high degree of plasticity to pre-differentiated cells, allowing them rapidly to begin assuming a polarized phenotype in response to extracellular stimuli without requiring the synthesis of epithelial cell-specific transport machinery.
The cytoskeleton in development of epithelial cell polarity
Authors: Fath Karl R. , Mamajiwalla Salim N. , Burgess David R. 
Published: May 2013

ABSTRACT
The polarization of intestinal epithelial cells and the stereotypic arrangement of their actin-based cytoskeleton have made these epithelia an excellent system to explore the organization and formation of a cortical actin-based cytoskeleton. Through a combined morphological and biochemical analysis, the molecular arrangement of many of the components of the brush border has been elucidated. Study of brush border assembly in the Crypts of Lieberkuhn suggests that cytoskeletal mRNA and protein expression, as well as morphological development, occur rapidly following cell differentiation. Protein kinases appear to be important regulators of intestinal cell growth, for differentiating cells in the crypts possess 15-fold higher levels of tyrosine phosphorylated proteins than differentiated cells of the villus. One of these kinases, pp60C STC, has a 4-to 7-fold higher activity in crypts and increased association with the cytoskeleton than it has in villus cells.
The development and maintenance of polarization in epithelial cells require the targeting and transport of specific proteins to the apical and basolateral plasma membrane. It has been proposed that a dynein-like, microtubule-based motor is involved in the transport of apically directed materials from the trans-Golgi to the apical plasma membrane. However, microtubules do not reach the plasma membrane, but terminate below the actin-rich network of filaments comprising the terminal web. We propose that vesicles translocate from the Golgi to the apical cytoplasm along microtubules using dynein, and then move through the terminal web to reach the apical plasma membrane using the actin-based motor myosin-I. Our isolation of Golgi-derived vesicles possessing both myosin-I and dynein on their cytoplasmic surface is consistent with this hypothesis.
Involvement of neurofilaments in motor neuron disease
Authors: Xu Zuoshang , Cork Linda C. , Griffin John W. , Cleveland Don W. 
Published: May 2013

ABSTRACT
Motor neuron disease is clinically characterized by progressive muscle wasting leading to total muscle paralysis. A long history of pathological study of patients has firmly established that the primary lesion site is in spinal and cortical motor neurons. In addition to the widespread loss of these neurons, neuronal abnormalities including massive accumulation of neurofilaments in cell bodies and proximal axons have been also widely observed, particularly in the early stages of the disease. To test whether high accumulation of neurofilaments directly contributes to the pathogenic process, transgenic mice that produce high levels of neurofilaments in motor neurons have been generated. These transgenic mice show most of the hallmarks observed in motor neuron disease, including swollen perikarya with eccentrically localized nuclei, proximal axonal swellings, axonal degeneration and severe skeletal muscle atrophy. These data indicate that extensive accumulation of neurofilaments in motor neurons can trigger a neurodegenerative process and may be a key intermediate in the pathway of pathogenesis leading to neuronal loss.
The retinal pigment epithelium: a versatile partner in vision
Authors: Bok Dean 
Published: May 2013

ABSTRACT
The retinal pigment epithelium (RPE) is a monolayer of cuboidal cells that lies in close association with the rod and cone photoreceptors. This epithelium has diverse features, three of which are discussed in some detail in this review, namely the daily phagocytosis of rod and cone outer segment fragments that are shed from their distal ends; the uptake, processing, transport and release of vitamin A (retinol) and some of its visual cycle intermediates (retinoids); and some of the aspects of its apical and basolateral membrane polarity that are the reverse of most other epithelia.
Phagocytosis takes place at the apical surface via membrane receptor-mediated processes that are not yet well defined. Retinol uptake occurs at both the basolateral and apical surfaces by what appear to be separate receptor-mediated processes. The release of a crucial retinoid, 11-cis retinaldehyde (11-cis retinal), occurs solely across the apical membrane. Delivery of retinol across the basolateral membrane is mediated by a retinol binding protein (RBP) that is secreted by the liver as a complex with retinol (vitamin A). Within the cell, retinol and its derivatives are solubilized by intracellular retinoid binding proteins that are selective for retinol (cellular retinol binding protein, CRBP) and 11-cis retinoids (cellular retinal binding protein, CRALBP). Release of ll-cis retinal across the apical membrane and re-uptake of retinol from the photoreceptors during the visual cycle is promoted by an intercellular retinoid binding protein (IRBP).
Na,K-ATPase, the membrane-integrated enzyme required to set up the ion gradients that drive other ion transporters, is largely localized to the apical membrane. This is the reverse of most epithelia. The RPE expresses the enveloped viral G protein and hemagglutinin on its basolateral and apical surface, respectively and does not appear to possess a general scheme for reversal of memrane protein polarity. Therefore possible alternative mechanisms for this reversal in Na,K-ATPase polarity are discussed. They include unique domains in the primary amino acid sequence of Na,K-ATPase subunits, cytoskeletal elements and components of the extracellular matrix. The precise mechanism remains unresolved.
An electron microscopic study of TGN38/41 dynamics
Authors: Ladinsky Mark S. , Howell Kathryn E. 
Published: May 2013

ABSTRACT
We have used electron microscopy to further characterize details of the dynamics of TGN38/41, a protein found to cycle between the frans-Golgi network and the plasma membrane. Immunogold-labeling of NRK cells under steady-state conditions shows the majority of TGN38/41 is localized to the trans-most Golgi cisternae and the irans-Golgi network. Small amounts of this molecule can be detected in early endosomes. Capture of cycling TGN38/41 molecules at the cell surface altered the steady state distribution. This was accomplished by binding TGN38/41 luminal domain antibodies to solid supports (beads), which were introduced to the culture media of cells. As increasing numbers of antigen-antibody complexes formed, the beads were internalized by the ‘zippering mechanism’ of phagocytosis. This provides a system that can address many questions related to the function of TGN38/41 and the trans-Golgi network itself.
Reliability and reproducibility of spectral and time domain optical coherence tomography images before and after correction for patients with age-related macular degeneration
Authors: Rashid Aymen , Sepah Yasir J , Channa Roomasa , Hatef Elham , Shulman Matthew , Do Diana V , Nguyen Quan Dong 
Published: May 2013

Purpose: To evaluate the reproducibility and reliability of Optical Coherence Tomography scans (OCT) obtained using the Time Domain (TD-OCT) StratusTM OCT, and the Spectral Domain (SD-OCT) SpectralisTM and CirrusTM OCT devices before and after manual correction in eyes with either Neovascular (NV-AMD) or Non-Neovascular (NNV-AMD) Age-related Macular Degeneration.Methods: We conducted a prospective observational study of 36 patients (50 eyes) with NV-AMD or NNV-AMD at a university-based retina practice. OCT scans were taken simultaneously using one TD-OCT and two SD-OCT devices. Macular thickness measurements were assessed before and after correction of the OCT algorithm by constructing Bland-Altman plots for agreement and calculating intraclass correlation coefficients (ICCs) and coefficients of repeatability (COR) to evaluate intraclass repeatability.Results: The Spectralis device had the highest number of images needing manual correction. All machines had high ICCs, with Spectralis having the highest. Bland-Altman plots indicated that there was low agreement between both Cirrus™ and Stratus™ and Spectralis™ and Stratus™, while there was good agreement between the Cirrus™ and Spectralis™ devices. The CORs were lowest for SpectralisTM and similar with each other and had higher values for CirrusTM and StratusTM. Agreement, CORs, and ICCs generally improved after manual correction, but only minimally. Conclusion: Agreement is low between devices, except between both SD-OCT machines. Manual correction tends to improve results.
Understanding dynamic milking machine tests
Authors: Allcock James , Postma Epi 
Published: May 2013

The milking machine can transmit infection onto teats and disturb normal teat health. Milking-time tests allow advisors to quantify the degree to which the milking machine might be contributing to the risk of new intra-mammary infection. Cows' teat size and position have changed as have milk flow rates. Milk yields have been rising faster than unit attachment times. Milk flow rate has been shown to be positively associated with risk of new intra-mammary infection. Vacuum traces collected during milking can illustrate problems with biphasic milk flow or over milking and pressure records can help assess liner function. Lightweight data logging equipment is now available with excellent software to assist with interpretation.
An Open-Label Safety Study of Lapatinib Plus Trastuzumab Plus Paclitaxel in First-Line HER2-Positive Metastatic Breast Cancer
Authors: Esteva Francisco J. , Franco Sandra X. , Hagan Maura K. , Brewster Abenaa M. , Somer Robert A. , Williams Will , Florance Allison M. , Turner Simon , Stein Steven , Perez Alejandra 
Published: May 2013

Abstract

Background.
Recent data support the hypothesis that combining lapatinib and trastuzumab with taxane chemotherapy may offer added clinical benefit to patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). This study examined the safety of the triplet combination in first-line HER2-positive MBC.

Patients and Methods.
Patients were enrolled into three sequential cohorts; the last two cohorts were added by protocol amendment following review of safety data from cohort 1. Patients in cohort 1 received lapatinib (1000 mg/day) plus paclitaxel (80 mg/m2 per week, 3 of every 4 weeks); cohort 2 received lapatinib (1000 mg/day) plus paclitaxel (70 mg/m2 per week, 3 of every 4 weeks); and cohort 3 received lapatinib (750 mg/day) plus paclitaxel (80 mg/m2 per week, 3 of every 4 weeks). All received standard trastuzumab dosing. The primary objective was assessment of dose-limiting toxicities, safety, and tolerability of this combination.

Results.
The most frequent adverse events (AEs) for all cohorts were diarrhea (89%), rash (79%), fatigue (73%), alopecia (63%), nausea (63%), and vomiting (40%). In cohorts 1 and 2, the incidence of grade 3 diarrhea was 62% and 50%, respectively; in cohort 3, the incidence was 25% (with prophylactic loperamide). Dehydration was the most frequent serious AE (10%). Across cohorts, overall response rate was 75%.

Conclusions.
The dose-limiting toxicity of paclitaxel, trastuzumab, and lapatinib in first-line HER2-positive MBC was diarrhea. Of the triplet combinations tested, the cohort receiving 750 mg/day dose of lapatinib had the lowest incidence of diarrhea; therefore, this dose should be used in further studies on the treatment of MBC.
Disturbance regime alters the impact of dispersal on alpha and beta diversity in a natural metacommunity
Authors: Vanschoenwinkel Bram , Buschke Falko , Brendonck Luc 
Published: May 2013

Disturbance and dispersal are two fundamental ecological processes that shape diversity patterns, yet their interaction and the underlying mechanisms are still poorly understood, and evidence from natural systems is particularly lacking. Using an invertebrate rock pool metacommunity in South Africa as a natural model system, we studied potential interactive effects of disturbance regime and patch isolation on diversity patterns of species with contrasting dispersal modes (passive vs. active dispersal).Isolation and disturbance regime had negative synergistic effects on alpha diversity: both directly, by excluding late‐successional species from isolated patches; and indirectly, by modulating establishment success of generalist predators in well‐connected patches. Unimodal relationships between isolation and alpha diversity, as predicted by mass effects, were only detected for passive dispersers in frequently disturbed patches and not in active dispersers. For passive dispersers, indications for a positive effect of isolation and a negative effect of disturbance on beta diversity were found, presumably due to differences in deterministic succession and stochastic colonization–extinction dynamics among different patch types. Our findings illustrate that interactions between dispersal rates and disturbance regime are important when explaining species diversity patterns in metacommunities and support the idea that diversity in frequently disturbed habitats is more sensitive to effects of dispersal‐based processes.