The expression of myosin genes in developing skeletal muscle in the mouse embryo

International Nuclear Information System (INIS)

Lyons, G.E.; Ontell, M.; Cox, R.; Sassoon, D.; Buckingham, M.

1990-01-01

Using in situ hybridization, we have investigated the temporal sequence of myosin gene expression in the developing skeletal muscle masses of mouse embryos. The probes used were isoform-specific, 35S-labeled antisense cRNAs to the known sarcomeric myosin heavy chain and myosin alkali light chain gene transcripts. Results showed that both cardiac and skeletal myosin heavy chain and myosin light chain mRNAs were first detected between 9 and 10 d post coitum (p.c.) in the myotomes of the most rostral somites. Myosin transcripts appeared in more caudal somites at later stages in a developmental gradient. The earliest myosin heavy chain transcripts detected code for the embryonic skeletal (MHCemb) and beta-cardiac (MHC beta) isoforms. Perinatal myosin heavy chain (MHCpn) transcripts begin to accumulate at 10.5 d p.c., which is much earlier than previously reported. At this stage, MHCemb is the major MHC transcript. By 12.5 d p.c., MHCpn and MHCemb mRNAs are present to an equal extent, and by 15.5 d p.c. the MHCpn transcript is the major MHC mRNA detected. Cardiac MHC beta transcripts are always present as a minor component. In contrast, the cardiac MLC1A mRNA is initially more abundant than that encoding the skeletal MLC1F isoform. By 12.5 d p.c. the two MLC mRNAs are present at similar levels, and by 15.5 d p.c., MLC1F is the predominant MLC transcript detected. Transcripts for the ventricular/slow (MLC1V) and another fast skeletal myosin light chain (MLC3F) are not detected in skeletal muscle before 15 d p.c., which marks the beginning of the fetal stage of muscle development. This is the first stage at which we can detect differences in expression of myosin genes between developing muscle fibers. We conclude that, during the development of the myotome and body wall muscles, different myosin genes follow independent patterns of activation and acculumation

The naked mole-rat exhibits an unusual cardiac myofilament protein profile providing new insights into heart function of this naturally subterranean rodent.

Science.gov (United States)

Grimes, Kelly M; Barefield, David Y; Kumar, Mohit; McNamara, James W; Weintraub, Susan T; de Tombe, Pieter P; Sadayappan, Sakthivel; Buffenstein, Rochelle

2017-12-01

The long-lived, hypoxic-tolerant naked mole-rat well-maintains cardiac function over its three-decade-long lifespan and exhibits many cardiac features atypical of similar-sized laboratory rodents. For example, they exhibit low heart rates and resting cardiac contractility, yet have a large cardiac reserve. These traits are considered ecophysiological adaptations to their dank subterranean atmosphere of low oxygen and high carbon dioxide levels and may also contribute to negligible declines in cardiac function during aging. We asked if naked mole-rats had a different myofilament protein signature to that of similar-sized mice that commonly show both high heart rates and high basal cardiac contractility. Adult mouse ventricles predominantly expressed α-myosin heavy chain (97.9 ± 0.4%). In contrast, and more in keeping with humans, β myosin heavy chain was the dominant isoform (79.0 ± 2.0%) in naked mole-rat ventricles. Naked mole-rat ventricles diverged from those of both humans and mice, as they expressed both cardiac and slow skeletal isoforms of troponin I. This myofilament protein profile is more commonly observed in mice in utero and during cardiomyopathies. There were no species differences in phosphorylation of cardiac myosin binding protein-C or troponin I. Phosphorylation of both ventricular myosin light chain 2 and cardiac troponin T in naked mole-rats was approximately half that observed in mice. Myofilament function was also compared between the two species using permeabilized cardiomyocytes. Together, these data suggest a cardiac myofilament protein signature that may contribute to the naked mole-rat's suite of adaptations to its natural subterranean habitat.

Adaptation of slow myofibers: the effect of sustained BDNF treatment of extraocular muscles in infant nonhuman primates.

Science.gov (United States)

Willoughby, Christy L; Fleuriet, Jérome; Walton, Mark M; Mustari, Michael J; McLoon, Linda K

2015-06-01

We evaluated promising new treatment options for strabismus. Neurotrophic factors have emerged as a potential treatment for oculomotor disorders because of diverse roles in signaling to muscles and motor neurons. Unilateral treatment with sustained release brain-derived neurotrophic factor (BDNF) to a single lateral rectus muscle in infant monkeys was performed to test the hypothesis that strabismus would develop in correlation with extraocular muscle (EOM) changes during the critical period for development of binocularity. The lateral rectus muscles of one eye in two infant macaques were treated with sustained delivery of BDNF for 3 months. Eye alignment was assessed using standard photographic methods. Muscle specimens were analyzed to examine the effects of BDNF on the density, morphology, and size of neuromuscular junctions, as well as myofiber size. Counts were compared to age-matched controls. No change in eye alignment occurred with BDNF treatment. Compared to control muscle, neuromuscular junctions on myofibers expressing slow myosins had a larger area. Myofibers expressing slow myosin had larger diameters, and the percentage of myofibers expressing slow myosins increased in the proximal end of the muscle. Expression of BDNF was examined in control EOM, and observed to have strongest immunoreactivity outside the endplate zone. We hypothesize that the oculomotor system adapted to sustained BDNF treatment to preserve normal alignment. Our results suggest that BDNF treatment preferentially altered myofibers expressing slow myosins. This implicates BDNF signaling as influencing the slow twitch properties of EOM.

Single-fiber myosin heavy chain polymorphism during postnatal development: modulation by hypothyroidism

Science.gov (United States)

di Maso, N. A.; Caiozzo, V. J.; Baldwin, K. M.

2000-01-01

The primary objective of this study was to follow the developmental time course of myosin heavy chain (MHC) isoform transitions in single fibers of the rodent plantaris muscle. Hypothyroidism was used in conjunction with single-fiber analyses to better describe a possible linkage between the neonatal and fast type IIB MHC isoforms during development. In contrast to the general concept that developmental MHC isoform transitions give rise to muscle fibers that express only a single MHC isoform, the single-fiber analyses revealed a very high degree of MHC polymorphism throughout postnatal development. In the adult state, MHC polymorphism was so pervasive that the rodent plantaris muscles contained approximately 12-15 different pools of fibers (i.e., fiber types). The degree of polymorphism observed at the single-fiber level made it difficult to determine specific developmental schemes analogous to those observed previously for the rodent soleus muscle. However, hypothyroidism was useful in that it confirmed a possible link between the developmental regulation of the neonatal and fast type IIB MHC isoforms.

Metal cation controls phosphate release in the myosin ATPase.

Science.gov (United States)

Ge, Jinghua; Huang, Furong; Nesmelov, Yuri E

2017-11-01

Myosin is an enzyme that utilizes ATP to produce a conformational change generating a force. The kinetics of the myosin reverse recovery stroke depends on the metal cation complexed with ATP. The reverse recovery stroke is slow for MgATP and fast for MnATP. The metal ion coordinates the γ phosphate of ATP in the myosin active site. It is accepted that the reverse recovery stroke is correlated with the phosphate release; therefore, magnesium "holds" phosphate tighter than manganese. Magnesium and manganese are similar ions in terms of their chemical properties and the shell complexation; hence, we propose to use these ions to study the mechanism of the phosphate release. Analysis of octahedral complexes of magnesium and manganese show that the partial charge of magnesium is higher than that of manganese and the slightly larger size of manganese ion makes its ionic potential smaller. We hypothesize that electrostatics play a role in keeping and releasing the abstracted γ phosphate in the active site, and the stronger electric charge of magnesium ion holds γ phosphate tighter. We used stable myosin-nucleotide analog complex and Raman spectroscopy to examine the effect of the metal cation on the relative position of γ phosphate analog in the active site. We found that in the manganese complex, the γ phosphate analog is 0.01 nm further away from ADP than in the magnesium complex. We conclude that the ionic potential of the metal cation plays a role in the retention of the abstracted phosphate. © 2017 The Protein Society.

Partial fast-to-slow conversion of regenerating rat fast-twitch muscle by chronic low-frequency stimulation.

Science.gov (United States)

Pette, Dirk; Sketelj, Janez; Skorjanc, Dejan; Leisner, Elmi; Traub, Irmtrud; Bajrović, Fajko

2002-01-01

Chronic low-frequency stimulation (CLFS) of rat fast-twitch muscles induces sequential transitions in myosin heavy chain (MHC) expression from MHCIIb --> MHCIId/x --> MHCIIa. However, the 'final' step of the fast-to-slow transition, i.e., the upregulation of MHCI, has been observed only after extremely long stimulation periods. Assuming that fibre degeneration/regeneration might be involved in the upregulation of slow myosin, we investigated the effects of CLFS on extensor digitorum longus (EDL) muscles regenerating after bupivacaine-induced fibre necrosis. Normal, non-regenerating muscles responded to both 30- and 60-day CLFS with fast MHC isoform transitions (MHCIIb --> MHCIId --> MHCIIa) and only slight increases in MHCI. CLFS of regenerating EDL muscles caused similar transitions among the fast isoforms but, in addition, caused significant increases in MHCI (to approximately 30% relative concentration). Stimulation periods of 30 and 60 days induced similar changes in the regenerating bupivacaine-treated muscles, indicating that the upregulation of slow myosin was restricted to regenerating fibres, but only during an early stage of regeneration. These results suggest that satellite cells and/or regenerating fast rat muscle fibres are capable of switching directly to a slow program under the influence of CLFS and, therefore, appear to be more malleable than adult fibres.

Smooth muscle myosin light chain kinase efficiently phosphorylates serine 15 of cardiac myosin regulatory light chain

International Nuclear Information System (INIS)

Josephson, Matthew P.; Sikkink, Laura A.; Penheiter, Alan R.; Burghardt, Thomas P.; Ajtai, Katalin

2011-01-01

Highlights: ► Cardiac myosin regulatory light chain (MYL2) is phosphorylated at S15. ► Smooth muscle myosin light chain kinase (smMLCK) is a ubiquitous kinase. ► It is a widely believed that MYL2 is a poor substrate for smMLCK. ► In fact, smMLCK efficiently and rapidly phosphorylates S15 in MYL2. ► Phosphorylation kinetics measured by novel fluorescence method without radioactivity. -- Abstract: Specific phosphorylation of the human ventricular cardiac myosin regulatory light chain (MYL2) modifies the protein at S15. This modification affects MYL2 secondary structure and modulates the Ca 2+ sensitivity of contraction in cardiac tissue. Smooth muscle myosin light chain kinase (smMLCK) is a ubiquitous kinase prevalent in uterus and present in other contracting tissues including cardiac muscle. The recombinant 130 kDa (short) smMLCK phosphorylated S15 in MYL2 in vitro. Specific modification of S15 was verified using the direct detection of the phospho group on S15 with mass spectrometry. SmMLCK also specifically phosphorylated myosin regulatory light chain S15 in porcine ventricular myosin and chicken gizzard smooth muscle myosin (S20 in smooth muscle) but failed to phosphorylate the myosin regulatory light chain in rabbit skeletal myosin. Phosphorylation kinetics, measured using a novel fluorescence method eliminating the use of radioactive isotopes, indicates similar Michaelis–Menten V max and K M for regulatory light chain S15 phosphorylation rates in MYL2, porcine ventricular myosin, and chicken gizzard myosin. These data demonstrate that smMLCK is a specific and efficient kinase for the in vitro phosphorylation of MYL2, cardiac, and smooth muscle myosin. Whether smMLCK plays a role in cardiac muscle regulation or response to a disease causing stimulus is unclear but it should be considered a potentially significant kinase in cardiac tissue on the basis of its specificity, kinetics, and tissue expression.

Smooth muscle myosin light chain kinase efficiently phosphorylates serine 15 of cardiac myosin regulatory light chain

Energy Technology Data Exchange (ETDEWEB)

Josephson, Matthew P.; Sikkink, Laura A. [Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905 (United States); Penheiter, Alan R. [Molecular Medicine Program, Mayo Clinic, Rochester, MN 55905 (United States); Burghardt, Thomas P., E-mail: burghardt@mayo.edu [Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905 (United States); Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905 (United States); Ajtai, Katalin [Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905 (United States)

2011-12-16

Highlights: Black-Right-Pointing-Pointer Cardiac myosin regulatory light chain (MYL2) is phosphorylated at S15. Black-Right-Pointing-Pointer Smooth muscle myosin light chain kinase (smMLCK) is a ubiquitous kinase. Black-Right-Pointing-Pointer It is a widely believed that MYL2 is a poor substrate for smMLCK. Black-Right-Pointing-Pointer In fact, smMLCK efficiently and rapidly phosphorylates S15 in MYL2. Black-Right-Pointing-Pointer Phosphorylation kinetics measured by novel fluorescence method without radioactivity. -- Abstract: Specific phosphorylation of the human ventricular cardiac myosin regulatory light chain (MYL2) modifies the protein at S15. This modification affects MYL2 secondary structure and modulates the Ca{sup 2+} sensitivity of contraction in cardiac tissue. Smooth muscle myosin light chain kinase (smMLCK) is a ubiquitous kinase prevalent in uterus and present in other contracting tissues including cardiac muscle. The recombinant 130 kDa (short) smMLCK phosphorylated S15 in MYL2 in vitro. Specific modification of S15 was verified using the direct detection of the phospho group on S15 with mass spectrometry. SmMLCK also specifically phosphorylated myosin regulatory light chain S15 in porcine ventricular myosin and chicken gizzard smooth muscle myosin (S20 in smooth muscle) but failed to phosphorylate the myosin regulatory light chain in rabbit skeletal myosin. Phosphorylation kinetics, measured using a novel fluorescence method eliminating the use of radioactive isotopes, indicates similar Michaelis-Menten V{sub max} and K{sub M} for regulatory light chain S15 phosphorylation rates in MYL2, porcine ventricular myosin, and chicken gizzard myosin. These data demonstrate that smMLCK is a specific and efficient kinase for the in vitro phosphorylation of MYL2, cardiac, and smooth muscle myosin. Whether smMLCK plays a role in cardiac muscle regulation or response to a disease causing stimulus is unclear but it should be considered a potentially significant

Human Usher 1B/mouse shaker-1: the retinal phenotype discrepancy explained by the presence/absence of myosin VIIA in the photoreceptor cells.

Science.gov (United States)

el-Amraoui, A; Sahly, I; Picaud, S; Sahel, J; Abitbol, M; Petit, C

1996-08-01

Usher syndrome type 1 (USH1) associates severe congenital deafness, vestibular dysfunction and progressive retinitis pigmentosa leading to blindness. The gene encoding myosin VIIA is responsible for USH1B. Mutations in the murine orthologous gene lead to the shaker-1 phenotype, which manifests cochlear and vestibular dysfunction, without any retinal defect. To address this phenotypic discrepancy, the expression of myosin VIIA in retinal cells was analyzed in human and mouse during embryonic development and adult life. In the human embryo, myosin VIIA was present first in the pigment epithelium cells, and later in these cells as well as in the photoreceptor cells. In the adult human retina, myosin VIIA was present in both cell types. In contrast, in mouse, only pigment epithelium cells expressed the protein throughout development and adult life. Myosin VIIA was also found to be absent in the photoreceptor cells of other rodents (rat and guinea-pig), whereas these cells expressed the protein in amphibians, avians and primates. These observations suggest that retinitis pigmentosa of USH1B results from a primary rod and cone defect. The USH1B/shaker-1 paradigm illustrates a species-specific cell pattern of gene expression as a possible cause for the discrepancy between phenotypes involving defective orthologous genes in man and mouse. Interestingly, in the photoreceptor cells, myosin VIIA is mainly localized in the inner and base of outer segments as well as in the synaptic ending region where it is co-localized with the synaptic vesicles. Therefore, we suggest that myosin VIIA might play a role in the trafficking of ribbon-synaptic vesicle complexes and the renewal processes of the outer photoreceptor disks.

Myosin Binding Protein-C Slow Phosphorylation is Altered in Duchenne Dystrophy and Arthrogryposis Myopathy in Fast-Twitch Skeletal Muscles.

Science.gov (United States)

Ackermann, Maegen A; Ward, Christopher W; Gurnett, Christina; Kontrogianni-Konstantopoulos, Aikaterini

2015-08-19

Myosin Binding Protein-C slow (sMyBP-C), encoded by MYBPC1, comprises a family of regulatory proteins of skeletal muscles that are phosphorylated by PKA and PKC. MYBPC1 missense mutations are linked to the development of Distal Arthrogryposis-1 (DA-1). Although structure-function details for this myopathy are evolving, function is undoubtedly driven by sequence variations and post-translational modifications in sMyBP-C. Herein, we examined the phosphorylation profile of sMyBP-C in mouse and human fast-twitch skeletal muscles. We used Flexor Digitorum Brevis (FDB) isolated from young (~2-months old) and old (~14-months old) wild type and mdx mice, and human Abductor Hallucis (AH) and gastrocnemious muscles carrying the DA-1 mutations. Our results indicate both constitutive and differential phosphorylation of sMyBP-C in aged and diseased muscles. We report a 7-35% reduction in the phosphorylation levels of select sites in old wild type and young or old mdx FDB mouse muscles, compared to young wild type tissue. Similarly, we observe a 30-70% decrease in the phosphorylation levels of all PKA and PKC phospho-sites in the DA-1 AH, but not gastrocnemius, muscle. Overall, our studies show that the phosphorylation pattern of sMyBP-C is differentially regulated in response to age and disease, suggesting that phosphorylation plays important roles in these processes.

Azidoblebbistatin, a photoreactive myosin inhibitor

Science.gov (United States)

Képiró, Miklós; Várkuti, Boglárka H.; Bodor, Andrea; Hegyi, György; Drahos, László; Kovács, Mihály; Málnási-Csizmadia, András

2012-01-01

Photoreactive compounds are important tools in life sciences that allow precisely timed covalent crosslinking of ligands and targets. Using a unique technique we have synthesized azidoblebbistatin, which is a derivative of blebbistatin, the most widely used myosin inhibitor. Without UV irradiation azidoblebbistatin exhibits identical inhibitory properties to those of blebbistatin. Using UV irradiation, azidoblebbistatin can be covalently crosslinked to myosin, which greatly enhances its in vitro and in vivo effectiveness. Photo-crosslinking also eliminates limitations associated with the relatively low myosin affinity and water solubility of blebbistatin. The wavelength used for photo-crosslinking is not toxic for cells and tissues, which confers a great advantage in in vivo tests. Because the crosslink results in an irreversible association of the inhibitor to myosin and the irradiation eliminates the residual activity of unbound inhibitor molecules, azidoblebbistatin has a great potential to become a highly effective tool in both structural studies of actomyosin contractility and the investigation of cellular and physiological functions of myosin II. We used azidoblebbistatin to identify previously unknown low-affinity targets of the inhibitor (EC50 ≥ 50 μM) in Dictyostelium discoideum, while the strongest interactant was found to be myosin II (EC50 = 5 μM). Our results demonstrate that azidoblebbistatin, and potentially other azidated drugs, can become highly useful tools for the identification of strong- and weak-binding cellular targets and the determination of the apparent binding affinities in in vivo conditions. PMID:22647605

Characteristics of myosin profile in human vastus lateralis muscle in relation to training background.

Science.gov (United States)

Zawadowska, B; Majerczak, J; Semik, D; Karasinski, J; Kolodziejski, L; Kilarski, W M; Duda, K; Zoladz, J A

2004-01-01

Twenty-four male volunteers (mean +/- SD: age 25.4+/-5.8 years, height 178.6+/-5.5 cm, body mass 72.1+/-7.7 kg) of different training background were investigated and classified into three groups according to their physical activity and sport discipline: untrained students (group A), national and sub-national level endurance athletes (group B, 7.8+/-2.9 years of specialised training) and sprint-power athletes (group C, 12.8+/-8.7 years of specialised training). Muscle biopsies of vastus lateralis were analysed histochemically for mATPase and SDH activities, immunohistochemically for fast and slow myosin, and electrophoretically followed by Western immunoblotting for myosin heavy chain (MyHC) composition. Significant differences (Pski-jumping, volleyball, soccer and modern dance. Furthermore, the relative amount of the fastest MyHCIIX isoform in vastus lateralis muscle was significantly lower in the athletes from group C than in students (group A). We conclude that the myosin profile in the athletes belonging to group C was unfavourable for their sport disciplines. This could be the reason why those athletes did not reach international level despite of several years of training.

Stimulatory and inhibitory mechanisms of slow muscle-specific myosin heavy chain gene expression in fish: Transient and transgenic analysis of torafugu MYHM86-2 promoter in zebrafish embryos

International Nuclear Information System (INIS)

Asaduzzaman, Md.; Kinoshita, Shigeharu; Bhuiyan, Sharmin Siddique; Asakawa, Shuichi; Watabe, Shugo

2013-01-01

The myosin heavy chain gene, MYH M86-2 , exhibited restricted expression in slow muscle fibers of torafugu embryos and larvae, suggesting its functional roles for embryonic and larval muscle development. However, the transcriptional mechanisms involved in its expression are still ambiguous. The present study is the first extensive analysis of slow muscle-specific MYH M86-2 promoter in fish for identifying the cis-elements that are crucial for its expression. Combining both transient transfection and transgenic approaches, we demonstrated that the 2614 bp 5′-flanking sequences of MYH M86-2 contain a sufficient promoter activity to drive gene expression specific to superficial slow muscle fibers. By cyclopamine treatment, we also demonstrated that the differentiation of such superficial slow muscle fibers depends on hedgehog signaling activity. The deletion analyses defined an upstream fragment necessary for repressing ectopic MYH M86-2 expression in the fast muscle fibers. The transcriptional mechanism that prevents MYH M86-2 expression in the fast muscle fibers is mediated through Sox6 binding elements. We also demonstrated that Sox6 may function as a transcriptional repressor of MYH M86-2 expression. We further discovered that nuclear factor of activated T cells (NFAT) binding elements plays a key role and myocyte enhancer factor-2 (MEF2) binding elements participate in the transcriptional regulation of MYH M86-2 expression. - Highlights: ► MYH M86-2 is highly expressed in slow muscle fibers of torafugu embryos and larvae. ► MYH M86-2 promoter activity depends on the hedgehog signaling. ► Sox6 binding elements inhibits MYH M86-2 expression in fast muscle fibers. ► Sox6 elements function as transcriptional repressor of MYH M86-2 promoter activity. ► NFAT and MEF2 binding elements play a key role for directing MYH M86-2 expression

Myosin phosphorylation improves contractile economy of mouse fast skeletal muscle during staircase potentiation.

Science.gov (United States)

Bunda, Jordan; Gittings, William; Vandenboom, Rene

2018-01-30

Phosphorylation of the myosin regulatory light chain (RLC) by skeletal myosin light chain kinase (skMLCK) potentiates rodent fast twitch muscle but is an ATP-requiring process. Our objective was to investigate the effect of skMLCK-catalyzed RLC phosphorylation on the energetic cost of contraction and the contractile economy (ratio of mechanical output to metabolic input) of mouse fast twitch muscle in vitro (25°C). To this end, extensor digitorum longus (EDL) muscles from wild-type (WT) and from skMLCK-devoid (skMLCK -/- ) mice were subjected to repetitive low-frequency stimulation (10 Hz for 15 s) to produce staircase potentiation of isometric twitch force, after which muscles were quick frozen for determination of high-energy phosphate consumption (HEPC). During stimulation, WT muscles displayed significant potentiation of isometric twitch force while skMLCK -/- muscles did not (i.e. 23% versus 5% change, respectively). Consistent with this, RLC phosphorylation was increased ∼3.5-fold from the unstimulated control value in WT but not in skMLCK -/- muscles. Despite these differences, the HEPC of WT muscles was not greater than that of skMLCK -/- muscles. As a result of the increased contractile output relative to HEPC, the calculated contractile economy of WT muscles was greater than that of skMLCK -/- muscles. Thus, our results suggest that skMLCK-catalyzed phosphorylation of the myosin RLC increases the contractile economy of WT mouse EDL muscle compared with skMLCK -/- muscles without RLC phosphorylation. © 2018. Published by The Company of Biologists Ltd.

Contractile properties, fiber types, and myosin isoforms in fast and slow muscles of hyperactive Japanese waltzing mice

Czech Academy of Sciences Publication Activity Database

Asmussen, G.; Schmalbruch, I.; Soukup, Tomáš; Pette, D.

2003-01-01

Roč. 184, č. 2 (2003), s. 758-766 ISSN 0014-4886 R&D Projects: GA ČR GA304/00/1653 Grant - others:Deutsche Forschungsgemeinschaft(DE) -; Sonderforschungsbereich(DE) 156; Schwerpunkt Muskelforschung(DE) As 74/1-2 Institutional research plan: CEZ:AV0Z5011922 Keywords : Japanese waltzing mouse * muscle contraction * myosin isoforms Subject RIV: ED - Physiology Impact factor: 3.676, year: 2003

Electron microscopic evidence for the myosin head lever arm mechanism in hydrated myosin filaments using the gas environmental chamber

International Nuclear Information System (INIS)

Minoda, Hiroki; Okabe, Tatsuhiro; Inayoshi, Yuhri; Miyakawa, Takuya; Miyauchi, Yumiko; Tanokura, Masaru; Katayama, Eisaku; Wakabayashi, Takeyuki; Akimoto, Tsuyoshi; Sugi, Haruo

2011-01-01

Research highlights: → We succeeded in recording structural changes of hydrated myosin cross-bridges. → We succeeded in position-marking the cross-bridges with site-directed antibodies. → We recorded cross-bridge movement at different regions in individual cross-bridge. → The movement was smallest at the cross-bridge-subfragment two boundary. → The results provide evidence for the cross-bridge lever arm mechanism. -- Abstract: Muscle contraction results from an attachment-detachment cycle between the myosin heads extending from myosin filaments and the sites on actin filaments. The myosin head first attaches to actin together with the products of ATP hydrolysis, performs a power stroke associated with release of hydrolysis products, and detaches from actin upon binding with new ATP. The detached myosin head then hydrolyses ATP, and performs a recovery stroke to restore its initial position. The strokes have been suggested to result from rotation of the lever arm domain around the converter domain, while the catalytic domain remains rigid. To ascertain the validity of the lever arm hypothesis in muscle, we recorded ATP-induced movement at different regions within individual myosin heads in hydrated myosin filaments, using the gas environmental chamber attached to the electron microscope. The myosin head were position-marked with gold particles using three different site-directed antibodies. The amplitude of ATP-induced movement at the actin binding site in the catalytic domain was similar to that at the boundary between the catalytic and converter domains, but was definitely larger than that at the regulatory light chain in the lever arm domain. These results are consistent with the myosin head lever arm mechanism in muscle contraction if some assumptions are made.

Distinct functional interactions between actin isoforms and nonsarcomeric myosins.

Directory of Open Access Journals (Sweden)

Mirco Müller

Full Text Available Despite their near sequence identity, actin isoforms cannot completely replace each other in vivo and show marked differences in their tissue-specific and subcellular localization. Little is known about isoform-specific differences in their interactions with myosin motors and other actin-binding proteins. Mammalian cytoplasmic β- and γ-actin interact with nonsarcomeric conventional myosins such as the members of the nonmuscle myosin-2 family and myosin-7A. These interactions support a wide range of cellular processes including cytokinesis, maintenance of cell polarity, cell adhesion, migration, and mechano-electrical transduction. To elucidate differences in the ability of isoactins to bind and stimulate the enzymatic activity of individual myosin isoforms, we characterized the interactions of human skeletal muscle α-actin, cytoplasmic β-actin, and cytoplasmic γ-actin with human myosin-7A and nonmuscle myosins-2A, -2B and -2C1. In the case of nonmuscle myosins-2A and -2B, the interaction with either cytoplasmic actin isoform results in 4-fold greater stimulation of myosin ATPase activity than was observed in the presence of α-skeletal muscle actin. Nonmuscle myosin-2C1 is most potently activated by β-actin and myosin-7A by γ-actin. Our results indicate that β- and γ-actin isoforms contribute to the modulation of nonmuscle myosin-2 and myosin-7A activity and thereby to the spatial and temporal regulation of cytoskeletal dynamics. FRET-based analyses show efficient copolymerization abilities for the actin isoforms in vitro. Experiments with hybrid actin filaments show that the extent of actomyosin coupling efficiency can be regulated by the isoform composition of actin filaments.

A global, myosin light chain kinase-dependent increase in myosin II contractility accompanies the metaphase-anaphase transition in sea urchin eggs.

Science.gov (United States)

Lucero, Amy; Stack, Christianna; Bresnick, Anne R; Shuster, Charles B

2006-09-01

Myosin II is the force-generating motor for cytokinesis, and although it is accepted that myosin contractility is greatest at the cell equator, the temporal and spatial cues that direct equatorial contractility are not known. Dividing sea urchin eggs were placed under compression to study myosin II-based contractile dynamics, and cells manipulated in this manner underwent an abrupt, global increase in cortical contractility concomitant with the metaphase-anaphase transition, followed by a brief relaxation and the onset of furrowing. Prefurrow cortical contractility both preceded and was independent of astral microtubule elongation, suggesting that the initial activation of myosin II preceded cleavage plane specification. The initial rise in contractility required myosin light chain kinase but not Rho-kinase, but both signaling pathways were required for successful cytokinesis. Last, mobilization of intracellular calcium during metaphase induced a contractile response, suggesting that calcium transients may be partially responsible for the timing of this initial contractile event. Together, these findings suggest that myosin II-based contractility is initiated at the metaphase-anaphase transition by Ca2+-dependent myosin light chain kinase (MLCK) activity and is maintained through cytokinesis by both MLCK- and Rho-dependent signaling. Moreover, the signals that initiate myosin II contractility respond to specific cell cycle transitions independently of the microtubule-dependent cleavage stimulus.

A Global, Myosin Light Chain Kinase-dependent Increase in Myosin II Contractility Accompanies the Metaphase–Anaphase Transition in Sea Urchin Eggs

Science.gov (United States)

Lucero, Amy; Stack, Christianna; Bresnick, Anne R.

2006-01-01

Myosin II is the force-generating motor for cytokinesis, and although it is accepted that myosin contractility is greatest at the cell equator, the temporal and spatial cues that direct equatorial contractility are not known. Dividing sea urchin eggs were placed under compression to study myosin II-based contractile dynamics, and cells manipulated in this manner underwent an abrupt, global increase in cortical contractility concomitant with the metaphase–anaphase transition, followed by a brief relaxation and the onset of furrowing. Prefurrow cortical contractility both preceded and was independent of astral microtubule elongation, suggesting that the initial activation of myosin II preceded cleavage plane specification. The initial rise in contractility required myosin light chain kinase but not Rho-kinase, but both signaling pathways were required for successful cytokinesis. Last, mobilization of intracellular calcium during metaphase induced a contractile response, suggesting that calcium transients may be partially responsible for the timing of this initial contractile event. Together, these findings suggest that myosin II-based contractility is initiated at the metaphase–anaphase transition by Ca2+-dependent myosin light chain kinase (MLCK) activity and is maintained through cytokinesis by both MLCK- and Rho-dependent signaling. Moreover, the signals that initiate myosin II contractility respond to specific cell cycle transitions independently of the microtubule-dependent cleavage stimulus. PMID:16837551

In situ hybridisation of a large repertoire of muscle-specific transcripts in fish larvae: the new superficial slow-twitch fibres exhibit characteristics of fast-twitch differentiation.

Science.gov (United States)

Chauvigné, F; Ralliere, C; Cauty, C; Rescan, P Y

2006-01-01

Much of the present information on muscle differentiation in fish concerns the early embryonic stages. To learn more about the maturation and the diversification of the fish myotomal fibres in later stages of ontogeny, we investigated, by means of in situ hybridisation, the developmental expression of a large repertoire of muscle-specific genes in trout larvae from hatching to yolk resorption. At hatching, transcripts for fast and slow muscle protein isoforms, namely myosins, tropomyosins, troponins and myosin binding protein C were present in the deep fast and the superficial slow areas of the myotome, respectively. During myotome expansion that follows hatching, the expression of fast isoforms became progressively confined to the borders of the fast muscle mass, whereas, in contrast, slow muscle isoform transcripts were uniformly expressed in all the slow fibres. Transcripts for several enzymes involved in oxidative metabolism such as citrate synthase, cytochrome oxidase component IV and succinate dehydrogenase, were present throughout the whole myotome of hatching embryos but in later stages became concentrated in slow fibre as well as in lateral fast fibres. Surprisingly, the slow fibres that are added externally to the single superficial layer of the embryonic (original) slow muscle fibres expressed not only slow twitch muscle isoforms but also, transiently, a subset of fast twitch muscle isoforms including MyLC1, MyLC3, MyHC and myosin binding protein C. Taken together these observations show that the growth of the myotome of the fish larvae is associated with complex patterns of muscular gene expression and demonstrate the unexpected presence of fast muscle isoform-expressing fibres in the most superficial part of the slow muscle.

Protective Effects of Clenbuterol against Dexamethasone-Induced Masseter Muscle Atrophy and Myosin Heavy Chain Transition.

Directory of Open Access Journals (Sweden)

Daisuke Umeki

Full Text Available Glucocorticoid has a direct catabolic effect on skeletal muscle, leading to muscle atrophy, but no effective pharmacotherapy is available. We reported that clenbuterol (CB induced masseter muscle hypertrophy and slow-to-fast myosin heavy chain (MHC isoform transition through direct muscle β2-adrenergic receptor stimulation. Thus, we hypothesized that CB would antagonize glucocorticoid (dexamethasone; DEX-induced muscle atrophy and fast-to-slow MHC isoform transition.We examined the effect of CB on DEX-induced masseter muscle atrophy by measuring masseter muscle weight, fiber diameter, cross-sectional area, and myosin heavy chain (MHC composition. To elucidate the mechanisms involved, we used immunoblotting to study the effects of CB on muscle hypertrophic signaling (insulin growth factor 1 (IGF1 expression, Akt/mammalian target of rapamycin (mTOR pathway, and calcineurin pathway and atrophic signaling (Akt/Forkhead box-O (FOXO pathway and myostatin expression in masseter muscle of rats treated with DEX and/or CB.Masseter muscle weight in the DEX-treated group was significantly lower than that in the Control group, as expected, but co-treatment with CB suppressed the DEX-induced masseter muscle atrophy, concomitantly with inhibition of fast-to-slow MHC isoforms transition. Activation of the Akt/mTOR pathway in masseter muscle of the DEX-treated group was significantly inhibited compared to that of the Control group, and CB suppressed this inhibition. DEX also suppressed expression of IGF1 (positive regulator of muscle growth, and CB attenuated this inhibition. Myostatin protein expression was unchanged. CB had no effect on activation of the Akt/FOXO pathway. These results indicate that CB antagonizes DEX-induced muscle atrophy and fast-to-slow MHC isoform transition via modulation of Akt/mTOR activity and IGF1 expression. CB might be a useful pharmacological agent for treatment of glucocorticoid-induced muscle atrophy.

CHARACTERIZATION OF TIGHTLY-ASSOCIATED SMOOTH MUSCLE MYOSIN-MYOSIN LIGHT CHAIN KINASE-CALMODULIN COMPLEXES*

OpenAIRE

Hong, Feng; Haldeman, Brian D.; John, Olivia A.; Brewer, Paul D.; Wu, Yi-Ying; Ni, Shaowei; Wilson, David P.; Walsh, Michael P.; Baker, Jonathan E.; Cremo, Christine R.

2009-01-01

A current popular model to explain phosphorylation of smooth muscle myosin (SMM) by smooth muscle myosin light chain kinase (MLCK) proposes that MLCK is bound tightly to actin but weakly to SMM. We found that MLCK and calmodulin (CaM) co-purify with unphosphorylated SMM (up-SMM) from chicken gizzard, suggesting that they are tightly bound. Although the MLCK:SMM molar ratio in SMM preparations was well below stoichiometric (1:73 ± 9), the ratio was ~ 23–37% of that in gizzard tissue. Fifteen t...

Cloning of skeletal myosin heavy chain gene family from adult pleopod muscle and whole larvae of shrimps.

Science.gov (United States)

Koyama, Hiroki; Piyapattanakorn, Sanit; Watabe, Shugo

2013-06-01

The physiological and biological properties of skeletal muscle in crustacea have not been well understood compared with those of vertebrates. The present study focused on myosin, the major protein in skeletal muscle, from shrimps. In our previous study, two full-length genes encoding myosin heavy chain (MHC), a large subunit of the myosin molecule, were cloned from abdominal fast skeletal muscle of kuruma Marsupenaeus japonicus, black tiger Penaeus monodon and Pacific white Penaeus vannamei shrimps, and named as MHCa and MHCb. In this study, we renamed these as MHC1 and MHC2, respectively, due to the presence of various isoforms newly identified. Partial MHC sequences were identified from pleopod muscle of these shrimps. Two MHCs, named MHC3 and MHC4, were identified from pleopod muscle of kuruma shrimp, whereas two MHCs, named MHC4 and MHC5, were cloned from Pacific white shrimp pleopod. MHC3 was cloned only from black tiger shrimp pleopod. Partial MHC sequences from zoea, mysis, and postlarvae of black tiger and Pacific white shrimps were also determined. The phylogenetic tree demonstrated that most MHCs from pleopod muscle and larval MHCs formed clades with MHC1 and MHC2, respectively. These MHCs were considered to be of fast type, since MHC1 and MHC2 are fast-type MHCs according to our previous study. MHC5 obtained from pleopod muscle of Pacific white shrimp in this study was monophyletic with American lobster Homarus americanus S2 slow tonic MHC previously reported, indicating that MHC5 from Pacific white shrimp is of slow type. Copyright © 2013 Wiley Periodicals, Inc.

Preparation of human cardiac anti-myosin: a review

International Nuclear Information System (INIS)

Okada, H.; Souza, I.T.T.

1990-01-01

The present communication is a review of the physicochemical characterization and immunological properties of myosin isolated from the cardiac muscle, the production of monoclonal antibody anti-myosin, the radiolabeling of this antibody and its applications as radiopharmaceuticals to imaging myocardial infarcts. The classical example of radioimmunologic diagnosis of non malignant tissues is the detection of myocardial infarction by radiolabeled antibodies to myosin. (author)

Myosin II dynamics are regulated by tension in intercalating cells.

Science.gov (United States)

Fernandez-Gonzalez, Rodrigo; Simoes, Sérgio de Matos; Röper, Jens-Christian; Eaton, Suzanne; Zallen, Jennifer A

2009-11-01

Axis elongation in Drosophila occurs through polarized cell rearrangements driven by actomyosin contractility. Myosin II promotes neighbor exchange through the contraction of single cell boundaries, while the contraction of myosin II structures spanning multiple pairs of cells leads to rosette formation. Here we show that multicellular actomyosin cables form at a higher frequency than expected by chance, indicating that cable assembly is an active process. Multicellular cables are sites of increased mechanical tension as measured by laser ablation. Fluorescence recovery after photobleaching experiments show that myosin II is stabilized at the cortex in regions of increased tension. Myosin II is recruited in response to an ectopic force and relieving tension leads to a rapid loss of myosin, indicating that tension is necessary and sufficient for cortical myosin localization. These results demonstrate that myosin II dynamics are regulated by tension in a positive feedback loop that leads to multicellular actomyosin cable formation and efficient tissue elongation.

Myosin Light Chain Kinase and the Role of Myosin Light Chain Phosphorylation in Skeletal Muscle

OpenAIRE

Stull, James T.; Kamm, Kristine E.; Vandenboom, Rene

2011-01-01

Skeletal muscle myosin light chain kinase (skMLCK) is a dedicated Ca2+/calmodulin-dependent serine-threonine protein kinase that phosphorylates the regulatory light chain (RLC) of sarcomeric myosin. It is expressed from the MYLK2 gene specifically in skeletal muscle fibers with most abundance in fast contracting muscles. Biochemically, activation occurs with Ca2+ binding to calmodulin forming a (Ca2+)4•calmodulin complex sufficient for activation with a diffusion limited, stoichiometic bindin...

Characterization of myosin light chain in shrimp hemocytic phagocytosis.

Science.gov (United States)

Han, Fang; Wang, Zhiyong; Wang, Xiaoqing

2010-11-01

Myosin light chain, a well-known cytoskeleton gene, regulates multiple processes that are involved in material transport, muscle shrink and cell division. However, its function in phagocytosis against invading pathogens in crustacean remains unknown. In this investigation, a myosin light chain gene was obtained from Marsupenaeus japonicus shrimp. The full-length cDNA of this gene was of 766 bp and an open reading frame (ORF) of 462 bp encoding a polypeptide of 153 amino acids. The myosin light chain protein was expressed in Escherichia coli and purified. Subsequently the specific antibody was raised using the purified GST fusion protein. As revealed by immuno-electron microscopy, the myosin light chain protein was only expressed in the dark bands of muscle. In the present study, the myosin light chain gene was up-regulated in the WSSV-resistant shrimp as revealed by real-time PCR and western blot. And the phagocytic percentage and phagocytic index using FITC-labeled Vibrio parahemolyticus were remarkably increased in the WSSV-resistant shrimp, suggesting that the myosin light chain protein was essential in hemocytic phagocytosis. On the other hand, RNAi assays indicated that the phagocytic percentage and phagocytic index were significantly decreased when the myosin light chain gene was silenced by sequence-specific siRNA. These findings suggested that myosin light chain protein was involved in the regulation of hemocytic phagocytosis of shrimp. Copyright 2010 Elsevier Ltd. All rights reserved.

Diverse functions of myosin VI elucidated by an isoform-specific α-helix domain.

Science.gov (United States)

Wollscheid, Hans-Peter; Biancospino, Matteo; He, Fahu; Magistrati, Elisa; Molteni, Erika; Lupia, Michela; Soffientini, Paolo; Rottner, Klemens; Cavallaro, Ugo; Pozzoli, Uberto; Mapelli, Marina; Walters, Kylie J; Polo, Simona

2016-04-01

Myosin VI functions in endocytosis and cell motility. Alternative splicing of myosin VI mRNA generates two distinct isoform types, myosin VI(short) and myosin VI(long), which differ in the C-terminal region. Their physiological and pathological roles remain unknown. Here we identified an isoform-specific regulatory helix, named the α2-linker, that defines specific conformations and hence determines the target selectivity of human myosin VI. The presence of the α2-linker structurally defines a new clathrin-binding domain that is unique to myosin VI(long) and masks the known RRL interaction motif. This finding is relevant to ovarian cancer, in which alternative myosin VI splicing is aberrantly regulated, and exon skipping dictates cell addiction to myosin VI(short) in tumor-cell migration. The RRL interactor optineurin contributes to this process by selectively binding myosin VI(short). Thus, the α2-linker acts like a molecular switch that assigns myosin VI to distinct endocytic (myosin VI(long)) or migratory (myosin VI(short)) functional roles.

Life without double-headed non-muscle myosin II motor proteins

Science.gov (United States)

Betapudi, Venkaiah

2014-07-01

Non-muscle myosin II motor proteins (myosin IIA, myosin IIB, and myosin IIC) belong to a class of molecular motor proteins that are known to transduce cellular free-energy into biological work more efficiently than man-made combustion engines. Nature has given a single myosin II motor protein for lower eukaryotes and multiple for mammals but none for plants in order to provide impetus for their life. These specialized nanomachines drive cellular activities necessary for embryogenesis, organogenesis, and immunity. However, these multifunctional myosin II motor proteins are believed to go awry due to unknown reasons and contribute for the onset and progression of many autosomal-dominant disorders, cataract, deafness, infertility, cancer, kidney, neuronal, and inflammatory diseases. Many pathogens like HIV, Dengue, hepatitis C, and Lymphoma viruses as well as Salmonella and Mycobacteria are now known to take hostage of these dedicated myosin II motor proteins for their efficient pathogenesis. Even after four decades since their discovery, we still have a limited knowledge of how these motor proteins drive cell migration and cytokinesis. We need to enrich our current knowledge on these fundamental cellular processes and develop novel therapeutic strategies to fix mutated myosin II motor proteins in pathological conditions. This is the time to think how to relieve the hijacked myosins from pathogens in order to provide a renewed impetus for patients’ life. Understanding how to steer these molecular motors in proliferating and differentiating stem cells will improve stem cell based-therapeutics development. Given the plethora of cellular activities non-muscle myosin motor proteins are involved in, their importance is apparent for human life.

Life without double-headed non-muscle myosin II motor proteins

Directory of Open Access Journals (Sweden)

Venkaiah eBetapudi

2014-07-01

Full Text Available Non-muscle myosin II motor proteins (myosin IIA, myosin IIB, and myosin IIC belong to a class of molecular motor proteins that are known to transduce cellular free-energy into biological work more efficiently than man-made combustion engines. Nature has given a single myosin II motor protein for lower eukaryotes and multiple for mammals but none for plants in order to provide impetus for their life. These specialized nanomachines drive cellular activities necessary for embryogenesis, organogenesis, and immunity. However, these multifunctional myosin II motor proteins are believed to go awry due to unknown reasons and contribute for the onset and progression of many autosomal-dominant disorders, cataract, deafness, infertility, cancer, kidney, neuronal, and inflammatory diseases. Many pathogens like HIV, Dengue, hepatitis C, and Lymphoma viruses as well as Salmonella and Mycobacteria are now known to take hostage of these dedicated myosin II motor proteins for their efficient pathogenesis. Even after four decades since their discovery, we still have a limited knowledge of how these motor proteins drive cell migration and cytokinesis. We need to enrich our current knowledge on these fundamental cellular processes and develop novel therapeutic strategies to fix mutated myosin II motor proteins in pathological conditions. This is the time to think how to relieve the hijacked myosins from pathogens in order to provide a renewed impetus for patients’ life. Understanding how to steer these molecular motors in proliferating and differentiating stem cells will improve stem cell based-therapeutics development. Given the plethora of cellular activities non-muscle myosin motor proteins are involved in, their importance is apparent for human life.

N-terminus of Cardiac Myosin Essential Light Chain Modulates Myosin Step-Size

Science.gov (United States)

Wang, Yihua; Ajtai, Katalin; Kazmierczak, Katarzyna; Szczesna-Cordary, Danuta; Burghardt, Thomas P.

2016-01-01

Muscle myosin cyclically hydrolyzes ATP to translate actin. Ventricular cardiac myosin (βmys) moves actin with three distinct unitary step-sizes resulting from its lever-arm rotation and with step-frequencies that are modulated in a myosin regulation mechanism. The lever-arm associated essential light chain (vELC) binds actin by its 43 residue N-terminal extension. Unitary steps were proposed to involve the vELC N-terminal extension with the 8 nm step engaging the vELC/actin bond facilitating an extra ~19 degrees of lever-arm rotation while the predominant 5 nm step forgoes vELC/actin binding. A minor 3 nm step is the unlikely conversion of the completed 5 to the 8 nm step. This hypothesis was tested using a 17 residue N-terminal truncated vELC in porcine βmys (Δ17βmys) and a 43 residue N-terminal truncated human vELC expressed in transgenic mouse heart (Δ43αmys). Step-size and step-frequency were measured using the Qdot motility assay. Both Δ17βmys and Δ43αmys had significantly increased 5 nm step-frequency and coincident loss in the 8 nm step-frequency compared to native proteins suggesting the vELC/actin interaction drives step-size preference. Step-size and step-frequency probability densities depend on the relative fraction of truncated vELC and relate linearly to pure myosin species concentrations in a mixture containing native vELC homodimer, two truncated vELCs in the modified homodimer, and one native and one truncated vELC in the heterodimer. Step-size and step-frequency, measured for native homodimer and at two or more known relative fractions of truncated vELC, are surmised for each pure species by using a new analytical method. PMID:26671638

Topology of interaction between titin and myosin thick filaments.

Science.gov (United States)

Kellermayer, Miklós; Sziklai, Dominik; Papp, Zsombor; Decker, Brennan; Lakatos, Eszter; Mártonfalvi, Zsolt

2018-05-05

Titin is a giant protein spanning between the Z- and M-lines of the sarcomere. In the A-band titin is associated with the myosin thick filament. It has been speculated that titin may serve as a blueprint for thick-filament formation due to the super-repeat structure of its A-band domains. Accordingly, titin might provide a template that determines the length and structural periodicity of the thick filament. Here we tested the titin ruler hypothesis by mixing titin and myosin at in situ stoichiometric ratios (300 myosins per 12 titins) in buffers of different ionic strength (KCl concentration range 100-300 mM). The topology of the filamentous complexes was investigated with atomic force microscopy. We found that the samples contained distinct, segregated populations of titin molecules and myosin thick filaments. We were unable to identify complexes in which myosin molecules were regularly associated to either mono- or oligomeric titin in either relaxed or stretched states of the titin filaments. Thus, the electrostatically driven self-association is stronger in both myosin and titin than their binding to each other, and it is unlikely that titin functions as a geometrical template for thick-filament formation. However, when allowed to equilibrate configurationally, long myosin thick filaments appeared with titin oligomers attached to their surface. The titin meshwork formed on the thick-filament surface may play a role in controlling thick-filament length by regulating the structural dynamics of myosin molecules and placing a mechanical limit on the filament length. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of proteolysis on the adenosinetriphosphatase activities of thymus myosin

International Nuclear Information System (INIS)

Vu, N.D.; Wagner, P.D.

1987-01-01

Limited proteolysis was used to identify regions on the heavy chains of calf thymus myosin which may be involved in ATP and actin binding. Assignments of the various proteolytic fragments to different parts of the myosin heavy chain were based on solubility, gel filtration, electron microscopy, and binding of 32 P-labeled regulatory light chains. Chymotrypsin rapidly cleaved within the head of thymus myosin to give a 70,000-dalton N-terminal fragment and a 140,000-dalton C-terminal fragment. These two fragments did not dissociate under nondenaturing conditions. Cleavage within the myosin tail to give heavy meromyosin occurred more slowly. Cleavage at the site 70,000 daltons from the N-terminus of the heavy chain caused about a 30-fold decrease in the actin concentration required to achieve half-maximal stimulation of the magnesium-adenosinetriphosphatase (Mg-ATPase) activity of unphosphorylated thymus myosin. The actin-activated ATPase activity of this digested myosin was only slightly affected by light chain phosphorylation. Actin inhibited the cleavage at this site by chymotrypsin. In the presence of ATP, chymotrypsin rapidly cleaved the thymus myosin heavy chain at an additional site about 4000 daltons from the N-terminus. Cleavage at this site caused a 2-fold increase in the ethylenediaminetetraacetic acid-ATPase activity and 3-fold decreases in the Ca 2+ - and Mg-ATPase activities of thymus myosin. Thus, cleavage at the N-terminus of thymus myosin was affected by ATP, and this cleavage altered ATPase activity. Papain cleaved the thymus myosin heavy chain about 94,000 daltons from the N-terminus to give subfragment 1. Although this subfragment 1 contained intact light chains, its actin-activated ATPase activity was not affected by light chain phosphorylation

Functions of myosin motors tailored for parasitism

DEFF Research Database (Denmark)

Mueller, Christina; Graindorge, Arnault; Soldati-Favre, Dominique

2017-01-01

Myosin motors are one of the largest protein families in eukaryotes that exhibit divergent cellular functions. Their roles in protozoans, a diverse group of anciently diverged, single celled organisms with many prominent members known to be parasitic and to cause diseases in human and livestock......, are largely unknown. In the recent years many different approaches, among them whole genome sequencing, phylogenetic analyses and functional studies have increased our understanding on the distribution, protein architecture and function of unconventional myosin motors in protozoan parasites. In Apicomplexa......, myosins turn out to be highly specialized and to exhibit unique functions tailored to accommodate the lifestyle of these parasites....

Reciprocal and dynamic polarization of planar cell polarity core components and myosin

Science.gov (United States)

Newman-Smith, Erin; Kourakis, Matthew J; Reeves, Wendy; Veeman, Michael; Smith, William C

2015-01-01

The Ciona notochord displays planar cell polarity (PCP), with anterior localization of Prickle (Pk) and Strabismus (Stbm). We report that a myosin is polarized anteriorly in these cells and strongly colocalizes with Stbm. Disruption of the actin/myosin machinery with cytochalasin or blebbistatin disrupts polarization of Pk and Stbm, but not of myosin complexes, suggesting a PCP-independent aspect of myosin localization. Wash out of cytochalasin restored Pk polarization, but not if done in the presence of blebbistatin, suggesting an active role for myosin in core PCP protein localization. On the other hand, in the pk mutant line, aimless, myosin polarization is disrupted in approximately one third of the cells, indicating a reciprocal action of core PCP signaling on myosin localization. Our results indicate a complex relationship between the actomyosin cytoskeleton and core PCP components in which myosin is not simply a downstream target of PCP signaling, but also required for PCP protein localization. DOI: http://dx.doi.org/10.7554/eLife.05361.001 PMID:25866928

Evolutionary traces decode molecular mechanism behind fast pace of myosin XI

Directory of Open Access Journals (Sweden)

Syamaladevi Divya P

2011-09-01

Full Text Available Abstract Background Cytoplasmic class XI myosins are the fastest processive motors known. This class functions in high-velocity cytoplasmic streaming in various plant cells from algae to angiosperms. The velocities at which they process are ten times faster than its closest class V homologues. Results To provide sequence determinants and structural rationale for the molecular mechanism of this fast pace myosin, we have compared the sequences from myosin class V and XI through Evolutionary Trace (ET analysis. The current study identifies class-specific residues of myosin XI spread over the actin binding site, ATP binding site and light chain binding neck region. Sequences for ET analysis were accumulated from six plant genomes, using literature based text search and sequence searches, followed by triple validation viz. CDD search, string-based searches and phylogenetic clustering. We have identified nine myosin XI genes in sorghum and seven in grape by sequence searches. Both the plants possess one gene product each belonging to myosin type VIII as well. During this process, we have re-defined the gene boundaries for three sorghum myosin XI genes using fgenesh program. Conclusion Molecular modelling and subsequent analysis of putative interactions involving these class-specific residues suggest a structural basis for the molecular mechanism behind high velocity of plant myosin XI. We propose a model of a more flexible switch I region that contributes to faster ADP release leading to high velocity movement of the algal myosin XI.

Mouse nuclear myosin I knock-out shows interchangeability and redundancy of myosin isoforms in the cell nucleus

Czech Academy of Sciences Publication Activity Database

Venit, Tomáš; Dzijak, Rastislav; Kalendová, Alžběta; Kahle, Michal; Rohožková, Jana; Schmidt, V.; Rülicke, T.; Rathkolb, B.; Hans, W.; Bohla, A.; Eickelberg, O.; Stoeger, T.; Wolf, E.; Yildirim, A.Ö.; Gailus-Durner, V.; Fuchs, H.; de Angelis, M.H.; Hozák, Pavel

2013-01-01

Roč. 8, č. 4 (2013), e61406 E-ISSN 1932-6203 R&D Projects: GA ČR GAP305/11/2232; GA TA ČR TE01020022; GA MŠk LH12143; GA ČR(CZ) GD204/09/H084 Institutional research plan: CEZ:AV0Z50520514 Institutional support: RVO:68378050 Keywords : nuclear myosin * myosin isoforms * cell nucleus Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.534, year: 2013

Myosin isoform fiber type and fiber size in the tail of the Virginia opossum (Didelphis virginiana).

Science.gov (United States)

Hazimihalis, P J; Gorvet, M A; Butcher, M T

2013-01-01

Muscle fiber type is a well studied property in limb muscles, however, much less is understood about myosin heavy chain (MHC) isoform expression in caudal muscles of mammalian tails. Didelphid marsupials are an interesting lineage in this context as all species have prehensile tails, but show a range of tail-function depending on either their arboreal or terrestrial locomotor habits. Differences in prehensility suggest that MHC isoform fiber types may also be different, in that terrestrial opossums may have a large distribution of oxidative fibers for object carrying tasks instead of faster, glycolytic fiber types expected in mammals with long tails. To test this hypothesis, MHC isoform fiber type and their regional distribution (proximal/transitional/distal) were determined in the tail of the Virginia opossum (Didelphis virginiana). Fiber types were determined by a combination of myosin-ATPase histochemistry, immunohistochemistry, and SDS-PAGE. Results indicate a predominance of the fast MHC-2A and -2X isoforms in each region of the tail. The presence of two fast isoforms, in addition to the slow MHC-1 isoform, was confirmed by SDS-PAGE analysis. The overall MHC isoform fiber type distribution for the tail was: 25% MHC-1, 71% MHC-2A/X hybrid, and 4% MHC-1/2A hybrid. Oxidative MHC-2A/X isoform fibers were found to be relatively large in cross-section compared to slow, oxidative MHC-1 and MHC-1/2A hybrid fibers. A large percentage of fast MHC-2A/X hybrids fibers may be suggestive of an evolutionary transition in MHC isoform distribution (fast-to-slow fiber type) in the tail musculature of an opossum with primarily a terrestrial locomotor habit and adaptive tail-function. Copyright © 2012 Wiley Periodicals, Inc.

Actin and myosin contribute to mammalian mitochondrial DNA maintenance

Science.gov (United States)

Reyes, A.; He, J.; Mao, C. C.; Bailey, L. J.; Di Re, M.; Sembongi, H.; Kazak, L.; Dzionek, K.; Holmes, J. B.; Cluett, T. J.; Harbour, M. E.; Fearnley, I. M.; Crouch, R. J.; Conti, M. A.; Adelstein, R. S.; Walker, J. E.; Holt, I. J.

2011-01-01

Mitochondrial DNA maintenance and segregation are dependent on the actin cytoskeleton in budding yeast. We found two cytoskeletal proteins among six proteins tightly associated with rat liver mitochondrial DNA: non-muscle myosin heavy chain IIA and β-actin. In human cells, transient gene silencing of MYH9 (encoding non-muscle myosin heavy chain IIA), or the closely related MYH10 gene (encoding non-muscle myosin heavy chain IIB), altered the topology and increased the copy number of mitochondrial DNA; and the latter effect was enhanced when both genes were targeted simultaneously. In contrast, genetic ablation of non-muscle myosin IIB was associated with a 60% decrease in mitochondrial DNA copy number in mouse embryonic fibroblasts, compared to control cells. Gene silencing of β-actin also affected mitochondrial DNA copy number and organization. Protease-protection experiments and iodixanol gradient analysis suggest some β-actin and non-muscle myosin heavy chain IIA reside within human mitochondria and confirm that they are associated with mitochondrial DNA. Collectively, these results strongly implicate the actomyosin cytoskeleton in mammalian mitochondrial DNA maintenance. PMID:21398640

Identification of signals that facilitate isoform specific nucleolar localization of myosin IC

Energy Technology Data Exchange (ETDEWEB)

Schwab, Ryan S.; Ihnatovych, Ivanna; Yunus, Sharifah Z.S.A.; Domaradzki, Tera [Department of Physiology and Biophysics, University at Buffalo—State University of New York, Buffalo, NY (United States); Hofmann, Wilma A., E-mail: whofmann@buffalo.edu [Department of Physiology and Biophysics, University at Buffalo—State University of New York, Buffalo, NY (United States)

2013-05-01

Myosin IC is a single headed member of the myosin superfamily that localizes to the cytoplasm and the nucleus, where it is involved in transcription by RNA polymerases I and II, intranuclear transport, and nuclear export. In mammalian cells, three isoforms of myosin IC are expressed that differ only in the addition of short isoform-specific N-terminal peptides. Despite the high sequence homology, the isoforms show differences in cellular distribution, in localization to nuclear substructures, and in their interaction with nuclear proteins through yet unknown mechanisms. In this study, we used EGFP-fusion constructs that express truncated or mutated versions of myosin IC isoforms to detect regions that are involved in isoform-specific localization. We identified two nucleolar localization signals (NoLS). One NoLS is located in the myosin IC isoform B specific N-terminal peptide, the second NoLS is located upstream of the neck region within the head domain. We demonstrate that both NoLS are functional and necessary for nucleolar localization of specifically myosin IC isoform B. Our data provide a first mechanistic explanation for the observed functional differences between the myosin IC isoforms and are an important step toward our understanding of the underlying mechanisms that regulate the various and distinct functions of myosin IC isoforms. - Highlights: ► Two NoLS have been identified in the myosin IC isoform B sequence. ► Both NoLS are necessary for myosin IC isoform B specific nucleolar localization. ► First mechanistic explanation of functional differences between the isoforms.

Characteristics of myosin profile in human vastus lateralis muscle in relation to training background.

Directory of Open Access Journals (Sweden)

J A Zoladz

2004-10-01

Full Text Available Twenty-four male volunteers (mean +/- SD: age 25.4+/-5.8 years, height 178.6+/-5.5 cm, body mass 72.1+/-7.7 kg of different training background were investigated and classified into three groups according to their physical activity and sport discipline: untrained students (group A, national and sub-national level endurance athletes (group B, 7.8+/-2.9 years of specialised training and sprint-power athletes (group C, 12.8+/-8.7 years of specialised training. Muscle biopsies of vastus lateralis were analysed histochemically for mATPase and SDH activities, immunohistochemically for fast and slow myosin, and electrophoretically followed by Western immunoblotting for myosin heavy chain (MyHC composition. Significant differences (P<0.05 regarding composition of muscle fibre types and myosin heavy chains were found only between groups A (41.7+/-1.6% of MyHCI, 40.8+/-4.0% of MyHCIIA and 17.5+/-4.0% of MyHCIIX and B (64.3+/-0.8% of MyHCI, 34.0+/-1.4% of MyHCIIA and 1.7+/-1.4% of MyHCIIX and groups A and C (59.6+/-1.6% of MyHCI, 37.2+/-1.3% of MyHCIIA and 3.2+/-1.3% of MyHCIIX. Unexpectedly, endurance athletes (group B such as long-distance runners, cyclists and cross country skiers, did not differ from the athletes representing short term, high power output sports (group C such as ice hockey, karate, ski-jumping, volleyball, soccer and modern dance. Furthermore, the relative amount of the fastest MyHCIIX isoform in vastus lateralis muscle was significantly lower in the athletes from group C than in students (group A. We conclude that the myosin profile in the athletes belonging to group C was unfavourable for their sport disciplines. This could be the reason why those athletes did not reach international level despite of several years of training.

Myosin VIIa as a common component of cilia and microvilli.

Science.gov (United States)

Wolfrum, U; Liu, X; Schmitt, A; Udovichenko, I P; Williams, D S

1998-01-01

The distribution of myosin VIIa, which is defective or absent in Usher syndrome 1B, was studied in a variety of tissues by immunomicroscopy. The primary aim was to determine whether this putative actin-based mechanoenzyme is a common component of cilia. Previously, it has been proposed that defective ciliary function might be the basis of some forms of Usher syndrome. Myosin VIIa was detected in cilia from cochlear hair cells, olfactory neurons, kidney distal tubules, and lung bronchi. It was also found to cofractionate with the axonemal fraction of retinal photoreceptor cells. Immunolabeling appeared most concentrated in the periphery of the transition zone of the cilia. This general presence of a myosin in cilia is surprising, given that cilia are dominated by microtubules, and not actin filaments. In addition to cilia, myosin VIIa was also found in actin-rich microvilli of different types of cell. We conclude that myosin VIIa is a common component of cilia and microvilli.

[Changes in titin and myosin heavy chain isoform composition in skeletal muscles of Mongolian gerbil (Meriones unguiculatus) after 12-day spaceflight].

Science.gov (United States)

Okuneva, A D; Vikhliantsev, I M; Shpagina, M D; Rogachevskiĭ, V V; Khutsian, S S; Poddubnaia, Z A; Grigor'ev, A I

2012-01-01

Changes of titin and myosin heavy chain isoform composition in skeletal muscles (m. soleus, m. gastrocnemius, m. tibialis anterior, m. psoas major) in Mongolian Gerbil (Meriones unguiculatus ) were investigated after 12-day spaceflight on board of Russian space vehicle "Foton-M3". In m. psoas and m. soleus in the gerbils from "Flight" group the expected increase in the content of fast myosin heavy chain isoforms (IIxd and IIa, respectively) were observed. No significant differences were found in the content of IIxd and IIa isoforms of myosin heavy chain in m. tibialis anterior in the gerbils from control group as compared to that in "Flight" group. An unexpected increase in the content of slow myosin heavy chain I isoform and a decrease in the content of fast IIx/d isoform in m. gastrocnemius of the gerbils from "Flight" group were observed. In skeletal muscles of the gerbils from "Flight" group the relative content of titin N2A-isoform was reduced (by 1,2-1,7 times), although the content of its NT-isoform, which was revealed in striated muscles of mammals in our experiments earlier, remained the same. When the content of titin N2A-isoform was decreased, no predictable abnormalities in sarcomeric structure and contractile ability of skeletal muscles in the gerbils from "Flight" group were found. An assumption on the leading role of titin NT-isoform in maintenance of structural and functional properties of striated muscles of mammals was made.

Biased Brownian motion mechanism for processivity and directionality of single-headed myosin-VI.

Science.gov (United States)

Iwaki, Mitsuhiro; Iwane, Atsuko Hikikoshi; Ikebe, Mitsuo; Yanagida, Toshio

2008-01-01

Conventional form to function as a vesicle transporter is not a 'single molecule' but a coordinated 'two molecules'. The coordinated two molecules make it complicated to reveal its mechanism. To overcome the difficulty, we adopted a single-headed myosin-VI as a model protein. Myosin-VI is an intracellular vesicle and organelle transporter that moves along actin filaments in a direction opposite to most other known myosin classes. The myosin-VI was expected to form a dimer to move processively along actin filaments with a hand-over-hand mechanism like other myosin organelle transporters. However, wild-type myosin-VI was demonstrated to be monomer and single-headed, casting doubt on its processivity. Using single molecule techniques, we show that green fluorescent protein (GFP)-fused single-headed myosin-VI does not move processively. However, when coupled to a 200 nm polystyrene bead (comparable to an intracellular vesicle in size) at a ratio of one head per bead, single-headed myosin-VI moves processively with large (40 nm) steps. Furthermore, we found that a single-headed myosin-VI-bead complex moved more processively in a high-viscous solution (40-fold higher than water) similar to cellular environment. Because diffusion of the bead is 60-fold slower than myosin-VI heads alone in water, we propose a model in which the bead acts as a diffusional anchor for the myosin-VI, enhancing the head's rebinding following detachment and supporting processive movement of the bead-monomer complex. This investigation will help us understand how molecular motors utilize Brownian motion in cells.

The Kinetics of Myosin Light Chain Kinase Activation of Smooth Muscle Myosin in an In Vitro Model System

OpenAIRE

Hong, Feng; Facemyer, Kevin C.; Carter, Michael S.; Jackson, Del R.; Haldeman, Brian D.; Ruana, Nick; Sutherland, Cindy; Walsh, Michael P.; Cremo, Christine R.; Baker, Josh E.

2013-01-01

During activation of smooth muscle contraction, one myosin light chain kinase (MLCK) molecule rapidly phosphorylates many smooth muscle myosin (SMM) molecules, suggesting that muscle activation rates are influenced by the kinetics of MLCK-SMM interactions. To determine the rate-limiting step underlying activation of SMM by MLCK, we measured the kinetics of calcium-calmodulin (Ca2+-CaM)-MLCK-mediated SMM phosphorylation and the corresponding initiation of SMM-based F-actin motility in an in vi...

A Role for Myosin Va in Human Cytomegalovirus Nuclear Egress.

Science.gov (United States)

Wilkie, Adrian R; Sharma, Mayuri; Pesola, Jean M; Ericsson, Maria; Fernandez, Rosio; Coen, Donald M

2018-03-15

Herpesviruses replicate and package their genomes into capsids in replication compartments within the nuclear interior. Capsids then move to the inner nuclear membrane for envelopment and release into the cytoplasm in a process called nuclear egress. We previously found that nuclear F-actin is induced upon infection with the betaherpesvirus human cytomegalovirus (HCMV) and is important for nuclear egress and capsid localization away from replication compartment-like inclusions toward the nuclear rim. Despite these and related findings, it has not been shown that any specific motor protein is involved in herpesvirus nuclear egress. In this study, we have investigated whether the host motor protein, myosin Va, could be fulfilling this role. Using immunofluorescence microscopy and coimmunoprecipitation, we observed associations between a nuclear population of myosin Va and the viral major capsid protein, with both concentrating at the periphery of replication compartments. Immunoelectron microscopy showed that nearly 40% of assembled nuclear capsids associate with myosin Va. We also found that myosin Va and major capsid protein colocalize with nuclear F-actin. Importantly, antagonism of myosin Va with RNA interference or a dominant negative mutant revealed that myosin Va is important for the efficient production of infectious virus, capsid accumulation in the cytoplasm, and capsid localization away from replication compartment-like inclusions toward the nuclear rim. Our results lead us to suggest a working model whereby human cytomegalovirus capsids associate with myosin Va for movement from replication compartments to the nuclear periphery during nuclear egress. IMPORTANCE Little is known regarding how newly assembled and packaged herpesvirus capsids move from the nuclear interior to the periphery during nuclear egress. While it has been proposed that an actomyosin-based mechanism facilitates intranuclear movement of alphaherpesvirus capsids, a functional role for

Engineering controllable bidirectional molecular motors based on myosin

Science.gov (United States)

Chen, Lu; Nakamura, Muneaki; Schindler, Tony D.; Parker, David; Bryant, Zev

2012-04-01

Cytoskeletal motors drive the transport of organelles and molecular cargoes within cells and have potential applications in molecular detection and diagnostic devices. Engineering molecular motors with controllable properties will allow selective perturbation of mechanical processes in living cells and provide optimized device components for tasks such as molecular sorting and directed assembly. Biological motors have previously been modified by introducing activation/deactivation switches that respond to metal ions and other signals. Here, we show that myosin motors can be engineered to reversibly change their direction of motion in response to a calcium signal. Building on previous protein engineering studies and guided by a structural model for the redirected power stroke of myosin VI, we have constructed bidirectional myosins through the rigid recombination of structural modules. The performance of the motors was confirmed using gliding filament assays and single fluorophore tracking. Our strategy, in which external signals trigger changes in the geometry and mechanics of myosin lever arms, should make it possible to achieve spatiotemporal control over a range of motor properties including processivity, stride size and branchpoint turning.

Dynamics of myosin II organization into cortical contractile networks and fibers

Science.gov (United States)

Nie, Wei; Wei, Ming-Tzo; Ou-Yang, Daniel; Jedlicka, Sabrina; Vavylonis, Dimitrios

2014-03-01

The morphology of adhered cells critically depends on the formation of a contractile meshwork of parallel and cross-linked stress fibers along the contacting surface. The motor activity and mini-filament assembly of non-muscle myosin II is an important component of cell-level cytoskeletal remodeling during mechanosensing. To monitor the dynamics of myosin II, we used confocal microscopy to image cultured HeLa cells that stably express myosin regulatory light chain tagged with GFP (MRLC-GFP). MRLC-GFP was monitored in time-lapse movies at steady state and during the response of cells to varying concentrations of blebbistatin which disrupts actomyosin stress fibers. Using image correlation spectroscopy analysis, we quantified the kinetics of disassembly and reassembly of actomyosin networks and compared them to studies by other groups. This analysis suggested that the following processes contribute to the assembly of cortical actomyosin into fibers: random myosin mini-filament assembly and disassembly along the cortex; myosin mini-filament aligning and contraction; stabilization of cortical myosin upon increasing contractile tension. We developed simple numerical simulations that include those processes. The results of simulations of cells at steady state and in response to blebbistatin capture some of the main features observed in the experiments. This study provides a framework to help interpret how different cortical myosin remodeling kinetics may contribute to different cell shape and rigidity depending on substrate stiffness.

Unconstrained steps of myosin VI appear longest among known molecular motors.

Science.gov (United States)

Ali, M Yusuf; Homma, Kazuaki; Iwane, Atsuko Hikikoshi; Adachi, Kengo; Itoh, Hiroyasu; Kinosita, Kazuhiko; Yanagida, Toshio; Ikebe, Mitsuo

2004-06-01

Myosin VI is a two-headed molecular motor that moves along an actin filament in the direction opposite to most other myosins. Previously, a single myosin VI molecule has been shown to proceed with steps that are large compared to its neck size: either it walks by somehow extending its neck or one head slides along actin for a long distance before the other head lands. To inquire into these and other possible mechanism of motility, we suspended an actin filament between two plastic beads, and let a single myosin VI molecule carrying a bead duplex move along the actin. This configuration, unlike previous studies, allows unconstrained rotation of myosin VI around the right-handed double helix of actin. Myosin VI moved almost straight or as a right-handed spiral with a pitch of several micrometers, indicating that the molecule walks with strides slightly longer than the actin helical repeat of 36 nm. The large steps without much rotation suggest kinesin-type walking with extended and flexible necks, but how to move forward with flexible necks, even under a backward load, is not clear. As an answer, we propose that a conformational change in the lifted head would facilitate landing on a forward, rather than backward, site. This mechanism may underlie stepping of all two-headed molecular motors including kinesin and myosin V.

Distribution and evolution of stable single α-helices (SAH domains in myosin motor proteins.

Directory of Open Access Journals (Sweden)

Dominic Simm

Full Text Available Stable single-alpha helices (SAHs are versatile structural elements in many prokaryotic and eukaryotic proteins acting as semi-flexible linkers and constant force springs. This way SAH-domains function as part of the lever of many different myosins. Canonical myosin levers consist of one or several IQ-motifs to which light chains such as calmodulin bind. SAH-domains provide flexibility in length and stiffness to the myosin levers, and may be particularly suited for myosins working in crowded cellular environments. Although the function of the SAH-domains in human class-6 and class-10 myosins has well been characterised, the distribution of the SAH-domain in all myosin subfamilies and across the eukaryotic tree of life remained elusive. Here, we analysed the largest available myosin sequence dataset consisting of 7919 manually annotated myosin sequences from 938 species representing all major eukaryotic branches using the SAH-prediction algorithm of Waggawagga, a recently developed tool for the identification of SAH-domains. With this approach we identified SAH-domains in more than one third of the supposed 79 myosin subfamilies. Depending on the myosin class, the presence of SAH-domains can range from a few to almost all class members indicating complex patterns of independent and taxon-specific SAH-domain gain and loss.

Myosin light chain kinase phosphorylation in tracheal smooth muscle

International Nuclear Information System (INIS)

Stull, J.T.; Hsu, L.C.; Tansey, M.G.; Kamm, K.E.

1990-01-01

Purified myosin light chain kinase from smooth muscle is phosphorylated by cyclic AMP-dependent protein kinase, protein kinase C, and the multifunctional calmodulin-dependent protein kinase II. Because phosphorylation in a specific site (site A) by any one of these kinases desensitizes myosin light chain kinase to activation by Ca2+/calmodulin, kinase phosphorylation could play an important role in regulating smooth muscle contractility. This possibility was investigated in 32 P-labeled bovine tracheal smooth muscle. Treatment of tissues with carbachol, KCl, isoproterenol, or phorbol 12,13-dibutyrate increased the extent of kinase phosphorylation. Six primary phosphopeptides (A-F) of myosin light chain kinase were identified. Site A was phosphorylated to an appreciable extent only with carbachol or KCl, agents which contract tracheal smooth muscle. The extent of site A phosphorylation correlated to increases in the concentration of Ca2+/calmodulin required for activation. These results show that cyclic AMP-dependent protein kinase and protein kinase C do not affect smooth muscle contractility by phosphorylating site A in myosin light chain kinase. It is proposed that phosphorylation of myosin light chain kinase in site A in contracting tracheal smooth muscle may play a role in the reported desensitization of contractile elements to activation by Ca2+

Actin-myosin network is required for proper assembly of influenza virus particles

Energy Technology Data Exchange (ETDEWEB)

Kumakura, Michiko; Kawaguchi, Atsushi, E-mail: ats-kawaguchi@md.tsukuba.ac.jp; Nagata, Kyosuke, E-mail: knagata@md.tsukuba.ac.jp

2015-02-15

Actin filaments are known to play a central role in cellular dynamics. After polymerization of actin, various actin-crosslinking proteins including non-muscle myosin II facilitate the formation of spatially organized actin filament networks. The actin-myosin network is highly expanded beneath plasma membrane. The genome of influenza virus (vRNA) replicates in the cell nucleus. Then, newly synthesized vRNAs are nuclear-exported to the cytoplasm as ribonucleoprotein complexes (vRNPs), followed by transport to the beneath plasma membrane where virus particles assemble. Here, we found that, by inhibiting actin-myosin network formation, the virus titer tends to be reduced and HA viral spike protein is aggregated on the plasma membrane. These results indicate that the actin-myosin network plays an important role in the virus formation. - Highlights: • Actin-myosin network is important for the influenza virus production. • HA forms aggregations at the plasma membrane in the presence of blebbistatin. • M1 is recruited to the budding site through the actin-myosin network.

Actin-myosin network is required for proper assembly of influenza virus particles

International Nuclear Information System (INIS)

Kumakura, Michiko; Kawaguchi, Atsushi; Nagata, Kyosuke

2015-01-01

Actin filaments are known to play a central role in cellular dynamics. After polymerization of actin, various actin-crosslinking proteins including non-muscle myosin II facilitate the formation of spatially organized actin filament networks. The actin-myosin network is highly expanded beneath plasma membrane. The genome of influenza virus (vRNA) replicates in the cell nucleus. Then, newly synthesized vRNAs are nuclear-exported to the cytoplasm as ribonucleoprotein complexes (vRNPs), followed by transport to the beneath plasma membrane where virus particles assemble. Here, we found that, by inhibiting actin-myosin network formation, the virus titer tends to be reduced and HA viral spike protein is aggregated on the plasma membrane. These results indicate that the actin-myosin network plays an important role in the virus formation. - Highlights: • Actin-myosin network is important for the influenza virus production. • HA forms aggregations at the plasma membrane in the presence of blebbistatin. • M1 is recruited to the budding site through the actin-myosin network

Effects of resistance training on fast- and slow-twitch muscles in rats

Directory of Open Access Journals (Sweden)

M Umnova

2010-09-01

Full Text Available The purpose of this study was to investigate the effect of resistance training (RT on muscle strength, the dependence of that on the fast-twitch (FT and slow-twitch (ST fibers hypertrophy, nuclear domain size, synthesis and degradation rate of contractile proteins and on the expression of myosin isoforms’. 16 weeks old Wistar rats were trained on a vertical treadmill for six days a week during six weeks. The power of exercise increased 4.9% per session. In RT group the mass of studied muscles increased about 10%, hindlimb grip strength increased from 5.20±0.27 N/100g bw to the 6.05±0.29 N/100g bw (p<0.05. Cross-sectional area and number of myonuclei of FT and ST fibers in plantaris (Pla and soleus (Sol muscles increased, myonuclear domain size did not change significantly. RT increased the MyHC IId isoforms relative content and decreased that of IIb and IIa isoforms in Pla muscle, in Sol muscle increased only IIa isoform. In Pla muscle the relative content of myosin light chain (MyLC 1slow and 2slow isoforms decreased and that of MyLC 2fast isoforms increased during RT. MyLC 3 and MyLC 2 ratio did not change significantly in Pla but increased in Sol muscle by 14.3±3.4�0(p<0.01. The rat RT programme caused hypertrophy of FT and ST muscle fibers, increase of myonuclear number via fusion of satellite cells with damaged fibers or formation of new muscle fibers as a result of myoblast fusion and myotubes formation, maintaining myonuclear domain size.

Myosin phosphatase Fine-tunes Zebrafish Motoneuron Position during Axonogenesis.

Directory of Open Access Journals (Sweden)

Juliane Bremer

2016-11-01

Full Text Available During embryogenesis the spinal cord shifts position along the anterior-posterior axis relative to adjacent tissues. How motor neurons whose cell bodies are located in the spinal cord while their axons reside in adjacent tissues compensate for such tissue shift is not well understood. Using live cell imaging in zebrafish, we show that as motor axons exit from the spinal cord and extend through extracellular matrix produced by adjacent notochord cells, these cells shift several cell diameters caudally. Despite this pronounced shift, individual motoneuron cell bodies stay aligned with their extending axons. We find that this alignment requires myosin phosphatase activity within motoneurons, and that mutations in the myosin phosphatase subunit mypt1 increase myosin phosphorylation causing a displacement between motoneuron cell bodies and their axons. Thus, we demonstrate that spinal motoneurons fine-tune their position during axonogenesis and we identify the myosin II regulatory network as a key regulator.

Sleep in the Cape Mole Rat: A Short-Sleeping Subterranean Rodent.

Science.gov (United States)

Kruger, Jean-Leigh; Gravett, Nadine; Bhagwandin, Adhil; Bennett, Nigel C; Archer, Elizabeth K; Manger, Paul R

2016-01-01

The Cape mole rat Georychus capensis is a solitary subterranean rodent found in the western and southern Cape of South Africa. This approximately 200-gram bathyergid rodent shows a nocturnal circadian rhythm, but sleep in this species is yet to be investigated. Using telemetric recordings of the electroencephalogram (EEG) and electromyogram (EMG) in conjunction with video recordings, we were able to show that the Cape mole rat, like all other rodents, has sleep periods composed of both rapid eye movement (REM) and slow-wave (non-REM) sleep. These mole rats spent on average 15.4 h awake, 7.1 h in non-REM sleep and 1.5 h in REM sleep each day. Cape mole rats sleep substantially less than other similarly sized terrestrial rodents but have a similar percentage of total sleep time occupied by REM sleep. In addition, the duration of both non-REM and REM sleep episodes was markedly shorter in the Cape mole rat than has been observed in terrestrial rodents. Interestingly, these features (total sleep time and episode duration) are similar to those observed in another subterranean bathyergid mole rat, i.e. Fukomys mechowii. Thus, there appears to be a bathyergid type of sleep amongst the rodents that may be related to their environment and the effect of this on their circadian rhythm. Investigating further species of bathyergid mole rats may fully define the emerging picture of sleep in these subterranean African rodents. © 2016 S. Karger AG, Basel.

Engineering controllable bidirectional molecular motors based on myosin

Science.gov (United States)

Chen, Lu; Nakamura, Muneaki; Schindler, Tony D.; Parker, David; Bryant, Zev

2012-01-01

Cytoskeletal motors drive the transport of organelles and molecular cargoes within cells1, and have potential applications in molecular detection and diagnostic devices2,3. Engineering molecular motors with dynamically controllable properties will allow selective perturbation of mechanical processes in living cells, and yield optimized device components for complex tasks such as molecular sorting and directed assembly3. Biological motors have previously been modified by introducing activation/deactivation switches that respond to metal ions4,5 and other signals6. Here we show that myosin motors can be engineered to reversibly change their direction of motion in response to a calcium signal. Building on previous protein engineering studies7–11 and guided by a structural model12 for the redirected power stroke of myosin VI, we constructed bidirectional myosins through the rigid recombination of structural modules. The performance of the motors was confirmed using gliding filament assays and single fluorophore tracking. Our general strategy, in which external signals trigger changes in the geometry and mechanics of myosin lever arms, should enable spatiotemporal control over a range of motor properties including processivity, stride size13, and branchpoint turning14. PMID:22343382

Characterization of human cardiac myosin heavy chain genes

International Nuclear Information System (INIS)

Yamauchi-Takihara, K.; Sole, M.J.; Liew, J.; Ing, D.; Liew, C.C.

1989-01-01

The authors have isolated and analyzed the structure of the genes coding for the α and β forms of the human cardiac myosin heavy chain (MYHC). Detailed analysis of four overlapping MYHC genomic clones shows that the α-MYHC and β-MYHC genes constitute a total length of 51 kilobases and are tandemly linked. The β-MYHC-encoding gene, predominantly expressed in the normal human ventricle and also in slow-twitch skeletal muscle, is located 4.5 kilobases upstream of the α-MYHC-encoding gene, which is predominantly expressed in normal human atrium. The authors have determined the nucleotide sequences of the β form of the MYHC gene, which is 100% homologous to the cardiac MYHC cDNA clone (pHMC3). It is unlikely that the divergence of a few nucleotide sequences from the cardiac β-MYHC cDNA clone (pHMC3) reported in a MYHC cDNA clone (PSMHCZ) from skeletal muscle is due to a splicing mechanism. This finding suggests that the same β form of the cardiac MYHC gene is expressed in both ventricular and slow-twitch skeletal muscle. The promoter regions of both α- and β-MYHC genes, as well as the first four coding regions in the respective genes, have also been sequenced. The sequences in the 5'-flanking region of the α- and β-MYHC-encoding genes diverge extensively from one another, suggesting that expression of the α- and β-MYHC genes is independently regulated

Myosin VIII regulates protonemal patterning and developmental timing in the moss Physcomitrella patens.

Science.gov (United States)

Wu, Shu-Zon; Ritchie, Julie A; Pan, Ai-Hong; Quatrano, Ralph S; Bezanilla, Magdalena

2011-09-01

Plants have two classes of myosins. While recent work has focused on class XI myosins showing that myosin XI is responsible for organelle motility and cytoplasmic streaming, much less is known about the role of myosin VIII in plant growth and development. We have used a combination of RNAi and insertional knockouts to probe myosin VIII function in the moss Physcomitrella patens. We isolated Δmyo8ABCDE plants demonstrating that myosin VIII is not required for plant viability. However, myosin VIII mutants are smaller than wild-type plants in part due to a defect in cell size. Additionally, Δmyo8ABCDE plants produce more side branches and form gametophores much earlier than wild-type plants. In the absence of nutrient media, Δmyo8ABCDE plants exhibit significant protonemal patterning defects, including highly curved protonemal filaments, morphologically defective side branches, as well as an increase in the number of branches. Exogenous auxin partially rescues protonemal defects in Δmyo8ABCDE plants grown in the absence of nutrients. This result, together with defects in protonemal branching, smaller caulonemal cells, and accelerated development in the Δmyo8ABCDE plants, suggests that myosin VIII is involved in hormone homeostasis in P. patens.

Structural insight into the UNC-45–myosin complex

DEFF Research Database (Denmark)

Fratev, Filip; Jonsdottir, Svava Osk; Pajeva, Ilza

2013-01-01

The UNC-45 chaperone protein interacts with and affects the folding, stability, and the ATPase activity of myosins. It plays a critical role in the cardiomyopathy development and in the breast cancer tumor growth. Here we propose the first structural model of the UNC-45–myosin complex using various...... is mainly stabilized by electrostatic interactions. Remarkably, the contact surface area is similar to that of the myosinactin complex. A significant interspecies difference in the myosin binding epitope is observed. Our results reveal the structural basis of MYH7 exons 15–16 hypertrophic cardiomyopathy...... mutations and provide directions for drug targeting. © 2013 Wiley Periodicals, Inc....

Effect of ageing on the myosin heavy chain composition of the human sternocleidomastoid muscle.

Science.gov (United States)

Meznaric, M; Eržen, I; Karen, P; Cvetko, E

2018-03-01

The myosin heavy chain (MyHC) composition of ageing limb muscles is transformed into a slower phenotype and expresses fast-twitch fibre type atrophy, presumably due to age-related motor unit remodelling and a change in the patterns of physical activity. It is not known if ageing affects the sternocleidomastoid muscle (SCM) in a similar way. The goal of the study was to analyze the MyHC composition and the size of muscle fibres in the ageing SCM by immunohistochemical methods and quantitative analysis and stereology using our own software for morphometry. We hypothesize that with ageing the MyHC composition of SCM transforms similarly as in ageing limb muscles, but the size of the muscle fibres is less effected as in limb muscles. The study was performed on the autopsy samples of the SCM in 12 older males. The results were compared with those published in our previous study on 15 young adult males. An ageing SCM transforms into a slower MyHC profile: the percentage of slow-twitch fibres is enhanced (numerical proportion 44.6 vs. 31.5%, Pfibres is diminished (numerical proportion 14.1 vs. 26.8%, Pfast-twitch fibres expressing MyHC-2a and 2x is smaller (50.6 vs. 63.5%, Pfibres expressing the fastest myosin isoform MyHC-2x is smaller too (19.0 vs. 34.5%, Pfibres expressing the fastest MyHC-2x provide circumstantial evidence for: (i) more fast-twitch than slow-twitch motor units being lost; and (ii) reinnervation by the surviving motor units. There appears to be no significant influence on muscle fibre size, which is congruent with relatively unchanged SCM activity during life. Copyright © 2017 Elsevier GmbH. All rights reserved.

Three-dimensional stochastic model of actin–myosin binding in the sarcomere lattice

Energy Technology Data Exchange (ETDEWEB)

Mijailovich, Srboljub M.; Kayser-Herold, Oliver; Stojanovic, Boban; Nedic, Djordje; Irving, Thomas C.; Geeves, MA (Harvard); (IIT); (U. Kent); (Kragujevac)

2016-11-18

The effect of molecule tethering in three-dimensional (3-D) space on bimolecular binding kinetics is rarely addressed and only occasionally incorporated into models of cell motility. The simplest system that can quantitatively determine this effect is the 3-D sarcomere lattice of the striated muscle, where tethered myosin in thick filaments can only bind to a relatively small number of available sites on the actin filament, positioned within a limited range of thermal movement of the myosin head. Here we implement spatially explicit actomyosin interactions into the multiscale Monte Carlo platform MUSICO, specifically defining how geometrical constraints on tethered myosins can modulate state transition rates in the actomyosin cycle. The simulations provide the distribution of myosin bound to sites on actin, ensure conservation of the number of interacting myosins and actin monomers, and most importantly, the departure in behavior of tethered myosin molecules from unconstrained myosin interactions with actin. In addition, MUSICO determines the number of cross-bridges in each actomyosin cycle state, the force and number of attached cross-bridges per myosin filament, the range of cross-bridge forces and accounts for energy consumption. At the macroscopic scale, MUSICO simulations show large differences in predicted force-velocity curves and in the response during early force recovery phase after a step change in length comparing to the two simplest mass action kinetic models. The origin of these differences is rooted in the different fluxes of myosin binding and corresponding instantaneous cross-bridge distributions and quantitatively reflects a major flaw of the mathematical description in all mass action kinetic models. Consequently, this new approach shows that accurate recapitulation of experimental data requires significantly different binding rates, number of actomyosin states, and cross-bridge elasticity than typically used in mass action kinetic models to

The structure of the actin-smooth muscle myosin motor domain complex in the rigor state.

Science.gov (United States)

Banerjee, Chaity; Hu, Zhongjun; Huang, Zhong; Warrington, J Anthony; Taylor, Dianne W; Trybus, Kathleen M; Lowey, Susan; Taylor, Kenneth A

2017-12-01

Myosin-based motility utilizes catalysis of ATP to drive the relative sliding of F-actin and myosin. The earliest detailed model based on cryo-electron microscopy (cryoEM) and X-ray crystallography postulated that higher actin affinity and lever arm movement were coupled to closure of a feature of the myosin head dubbed the actin-binding cleft. Several studies since then using crystallography of myosin-V and cryoEM structures of F-actin bound myosin-I, -II and -V have provided details of this model. The smooth muscle myosin II interaction with F-actin may differ from those for striated and non-muscle myosin II due in part to different lengths of important surface loops. Here we report a ∼6 Å resolution reconstruction of F-actin decorated with the nucleotide-free recombinant smooth muscle myosin-II motor domain (MD) from images recorded using a direct electron detector. Resolution is highest for F-actin and the actin-myosin interface (3.5-4 Å) and lowest (∼6-7 Å) for those parts of the MD at the highest radius. Atomic models built into the F-actin density are quite comparable to those previously reported for rabbit muscle actin and show density from the bound ADP. The atomic model of the MD, is quite similar to a recently published structure of vertebrate non-muscle myosin II bound to F-actin and a crystal structure of nucleotide free myosin-V. Larger differences are observed when compared to the cryoEM structure of F-actin decorated with rabbit skeletal muscle myosin subfragment 1. The differences suggest less closure of the 50 kDa domain in the actin bound skeletal muscle myosin structure. Copyright © 2017 Elsevier Inc. All rights reserved.

Expression of multiple slow myosin heavy chain genes reveals a diversity of zebrafish slow twitch muscle fibres with differing requirements for Hedgehog and Prdm1 activity.

Science.gov (United States)

Elworthy, Stone; Hargrave, Murray; Knight, Robert; Mebus, Katharina; Ingham, Philip W

2008-06-01

The zebrafish embryo develops a series of anatomically distinct slow twitch muscle fibres that characteristically express genes encoding lineage-specific isoforms of sarcomeric proteins such as MyHC and troponin. We show here that different subsets of these slow fibres express distinct members of a tandem array of slow MyHC genes. The first slow twitch muscle fibres to differentiate, which are specified by the activity of the transcription factor Prdm1 (also called Ubo or Blimp1) in response to Hedgehog (Hh) signalling, express the smyhc1 gene. Subsequently, secondary slow twitch fibres differentiate in most cases independently of Hh activity. We find that although some of these later-forming fibres also express smyhc1, others express smyhc2 or smyhc3. We show that the smyhc1-positive fibres express the ubo (prdm1) gene and adopt fast twitch fibre characteristics in the absence of Prdm1 activity, whereas those that do not express smyhc1 can differentiate independently of Prdm1 function. Conversely, some smyhc2-expressing fibres, although independent of Prdm1 function, require Hh activity to form. The adult trunk slow fibres express smyhc2 and smyhc3, but lack smyhc1 expression. The different slow fibres in the craniofacial muscles variously express smyhc1, smyhc2 and smyhc3, and all differentiate independently of Prdm1.

Oxidation of myosin by haem proteins generates myosin radicals and protein cross-links

DEFF Research Database (Denmark)

Lametsch, Marianne Lund; Luxford, Catherine; Skibsted, Leif Horsfelt

2008-01-01

of thiyl and tyrosyl radicals is consistent with the observed consumption of cysteine and tyrosine residues, the detection of di-tyrosine by HPLC and the detection of both reducible (disulfide bond) and non-reducible cross-links between myosin molecules by SDS/PAGE. The time course of radical formation...

Slit and Netrin-1 guide cranial motor axon pathfinding via Rho-kinase, myosin light chain kinase and myosin II

Directory of Open Access Journals (Sweden)

Drescher Uwe

2010-06-01

Full Text Available Abstract Background In the developing hindbrain, cranial motor axon guidance depends on diffusible repellent factors produced by the floor plate. Our previous studies have suggested that candidate molecules for mediating this effect are Slits, Netrin-1 and Semaphorin3A (Sema3A. It is unknown to what extent these factors contribute to floor plate-derived chemorepulsion of motor axons, and the downstream signalling pathways are largely unclear. Results In this study, we have used a combination of in vitro and in vivo approaches to identify the components of floor plate chemorepulsion and their downstream signalling pathways. Using in vitro motor axon deflection assays, we demonstrate that Slits and Netrin-1, but not Sema3A, contribute to floor plate repulsion. We also find that the axon pathways of dorsally projecting branchiomotor neurons are disrupted in Netrin-1 mutant mice and in chick embryos expressing dominant-negative Unc5a receptors, indicating an in vivo role for Netrin-1. We further demonstrate that Slit and Netrin-1 signalling are mediated by Rho-kinase (ROCK and myosin light chain kinase (MLCK, which regulate myosin II activity, controlling actin retrograde flow in the growth cone. We show that MLCK, ROCK and myosin II are required for Slit and Netrin-1-mediated growth cone collapse of cranial motor axons. Inhibition of these molecules in explant cultures, or genetic manipulation of RhoA or myosin II function in vivo causes characteristic cranial motor axon pathfinding errors, including the inability to exit the midline, and loss of turning towards exit points. Conclusions Our findings suggest that both Slits and Netrin-1 contribute to floor plate-derived chemorepulsion of cranial motor axons. They further indicate that RhoA/ROCK, MLCK and myosin II are components of Slit and Netrin-1 signalling pathways, and suggest that these pathways are of key importance in cranial motor axon navigation.

Proportions of myosin heavy chain mRNAs, protein isoforms and fiber types in the slow and fast skeletal muscles are maintained after alterations of thyroid status in rats.

Science.gov (United States)

Soukup, T; Diallo, M

2015-01-01

Recently, we have established that slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles of euthyroid (EU) Lewis rats posses the same proportions between their four myosin heavy chain (MyHC) mRNAs, protein isoforms and fiber types as determined by real time RT-PCR, SDS-PAGE and 2-D stereological fiber type analysis, respectively. In the present paper we investigated if these proportions are maintained in adult Lewis rats with hyperthyroid (HT) and hypothyroid (HY) status. Although HT and HY states change MyHC isoform expression, results from all three methods showed that proportion between MyHC mRNA-1, 2a, -2x/d, -2b, protein isoforms MyHC-1, -2a, -2x/d, -2b and to lesser extent also fiber types 1, 2A, 2X/D, 2B were preserved in both SOL and EDL muscles. Furthermore, in the SOL muscle mRNA expression of slow MyHC-1 remained up to three orders higher compared to fast MyHC transcripts, which explains the predominance of MyHC-1 isoform and fiber type 1 even in HT rats. Although HT status led in the SOL to increased expression of MyHC-2a mRNA, MyHC-2a isoform and 2A fibers, it preserved extremely low expression of MyHC-2x and -2b mRNA and protein isoforms, which explains the absence of pure 2X/D and 2B fibers. HY status, on the other hand, almost completely abolished expression of all three fast MyHC mRNAs, MyHC protein isoforms and fast fiber types in the SOL muscle. Our data present evidence that a correlation between mRNA, protein content and fiber type composition found in EU status is also preserved in HT and HY rats.

Slow-tonic muscle fibers and their potential innervation in the turtle, Pseudemys (Trachemys) scripta elegans.

Science.gov (United States)

Callister, Robert J; Pierce, Patricia A; McDonagh, Jennifer C; Stuart, Douglas G

2005-04-01

A description is provided of the ratio of slow-tonic vs. slow- and fast-twitch fibers for five muscles in the adult turtle, Pseudemys (Trachemys) scripta elegans. The cross-sectional area of each fiber type and an estimation of the relative (weighted) cross-sectional area occupied by the different fiber types are also provided. Two hindlimb muscles (flexor digitorum longus, FDL; external gastrocnemius, EG) were selected on the basis of their suitability for future motor-unit studies. Three neck muscles (the fourth head of testo-cervicis, TeC4; the fourth head of retrahens capitus collique, RCCQ4; transversalis cervicis, TrC) were chosen for their progressively decreasing oxidative capacity. Serial sections were stained for myosin adenosine triphosphatase (ATPase), NADH-diaphorase, and alpha-glycerophosphate dehydrogenase (alpha-GPDH). Conventional fiber-type classification was then performed using indirect markers for contraction speed and oxidative (aerobic) vs. glycolytic (anaerobic) metabolism: i.e., slow oxidative (SO, including slow-twitch and possibly slow-tonic fibers), fast-twitch, oxidative-glycolytic (FOG), and fast-twitch glycolytic (Fg) fibers. Slow-tonic fibers in the SO class were then revealed by directing the monoclonal antibody, ALD-58 (raised against the slow-tonic fiber myosin heavy chain of chicken anterior latissimus dorsi), to additional muscle cross sections. All five of the tested muscles contained the four fiber types, with the ATPase-stained fibers including both slow-tonic and slow-twitch fibers. The extreme distributions of SO fibers were in the predominately glycolytic TrC vs. the predominately oxidative TeC4 muscle (TrC-SO, 9%; FOG, 20%; Fg, 71% vs. TeC4-SO, 58%: FOG, 16%; Fg, 25%). Across the five muscles, the relative prevalence of slow-tonic fibers (4-47%) paralleled that of the SO fibers (9-58%). TeC4 had the highest prevalence of slow-tonic fibers (47%). The test muscles exhibited varying degrees of regional concentration of each

Catalytic strategy used by the myosin motor to hydrolyze ATP.

Science.gov (United States)

Kiani, Farooq Ahmad; Fischer, Stefan

2014-07-22

Myosin is a molecular motor responsible for biological motions such as muscle contraction and intracellular cargo transport, for which it hydrolyzes adenosine 5'-triphosphate (ATP). Early steps of the mechanism by which myosin catalyzes ATP hydrolysis have been investigated, but still missing are the structure of the final ADP·inorganic phosphate (Pi) product and the complete pathway leading to it. Here, a comprehensive description of the catalytic strategy of myosin is formulated, based on combined quantum-classical molecular mechanics calculations. A full exploration of catalytic pathways was performed and a final product structure was found that is consistent with all experiments. Molecular movies of the relevant pathways show the different reorganizations of the H-bond network that lead to the final product, whose γ-phosphate is not in the previously reported HPγO4(2-) state, but in the H2PγO4(-) state. The simulations reveal that the catalytic strategy of myosin employs a three-pronged tactic: (i) Stabilization of the γ-phosphate of ATP in a dissociated metaphosphate (PγO3(-)) state. (ii) Polarization of the attacking water molecule, to abstract a proton from that water. (iii) Formation of multiple proton wires in the active site, for efficient transfer of the abstracted proton to various product precursors. The specific role played in this strategy by each of the three loops enclosing ATP is identified unambiguously. It explains how the precise timing of the ATPase activation during the force generating cycle is achieved in myosin. The catalytic strategy described here for myosin is likely to be very similar in most nucleotide hydrolyzing enzymes.

Comparison of myosin heavy chain mRNAs, protein isoforms and fiber type proportions in the rat slow and fast muscles

Czech Academy of Sciences Publication Activity Database

Žurmanová, J.; Soukup, Tomáš

2013-01-01

Roč. 62, č. 4 (2013), s. 445-453 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA304/08/0256; GA ČR(CZ) GA305/09/1228; GA MŠk(CZ) 7AMB12SK158; GA MŠk(CZ) LH12058 Grant - others:EC(XE) LSH-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : rat * soleus * extensor digitorum longus * myosin heavy chain isoforms * muscle gene expression * quantitative Real Time RT-PCR * SDS - PAGE * fiber type analysis Subject RIV: EA - Cell Biology Impact factor: 1.487, year: 2013

Consumption of polyphenol plants may slow aging and associated diseases.

Science.gov (United States)

Uysal, Utku; Seremet, Sila; Lamping, Jeffrey W; Adams, Jerome M; Liu, Deede Y; Swerdlow, Russell H; Aires, Daniel J

2013-01-01

Slowing aging is a widely shared goal. Plant-derived polyphenols, which are found in commonly consumed food plants such as tea, cocoa, blueberry and grape, have been proposed to have many health benefits, including slowing aging. In-vivo studies have demonstrated the lifespan-extending ability of six polyphenol-containing plants. These include five widely consumed foods (tea, blueberry, cocoa, apple, pomegranate) and a flower commonly used as a folk medicine (betony). These and multiple other plant polyphenols have been shown to have beneficial effects on aging-associated changes across a variety of organisms from worm and fly to rodent and human.

Extracellular matrix-dependent myosin dynamics during G1-S phase cell cycle progression in hepatocytes

International Nuclear Information System (INIS)

Bhadriraju, Kiran; Hansen, Linda K.

2004-01-01

Cell spreading and proliferation are tightly coupled in anchorage-dependent cells. While adhesion-dependent proliferation signals require an intact actin cytoskeleton, and some of these signals such as ERK activation have been characterized, the role of myosin in spreading and cell cycle progression under different extracellular matrix (ECM) conditions is not known. Studies presented here examine changes in myosin activity in freshly isolated hepatocytes under ECM conditions that promote either proliferation (high fibronectin density) or growth arrest (low fibronectin density). Three different measures were obtained and related to both spreading and cell cycle progression: myosin protein levels and association with cytoskeleton, myosin light chain phosphorylation, and its ATPase activity. During the first 48 h in culture, corresponding with transit through G1 phase, there was a six-fold increase in both myosin protein levels and myosin association with actin cytoskeleton. There was also a steady increase in myosin light chain phosphorylation and ATPase activity with spreading, which did not occur in non-spread, growth-arrested cells on low density of fibronectin. Myosin-inhibiting drugs blocked ERK activation, cyclin D1 expression, and S phase entry. Overexpression of the cell cycle protein cyclin D1 overcame both ECM-dependent and actomyosin-dependent inhibition of DNA synthesis, suggesting that cyclin D1 is a key event downstream of myosin-dependent cell cycle regulation

Myonuclear domain size and myosin isoform expression in muscle fibres from mammals representing a 100,000-fold difference in body size.

Science.gov (United States)

Liu, Jing-Xia; Höglund, Anna-Stina; Karlsson, Patrick; Lindblad, Joakim; Qaisar, Rizwan; Aare, Sudhakar; Bengtsson, Ewert; Larsson, Lars

2009-01-01

This comparative study of myonuclear domain (MND) size in mammalian species representing a 100,000-fold difference in body mass, ranging from 25 g to 2500 kg, was undertaken to improve our understanding of myonuclear organization in skeletal muscle fibres. Myonuclear domain size was calculated from three-dimensional reconstructions in a total of 235 single muscle fibre segments at a fixed sarcomere length. Irrespective of species, the largest MND size was observed in muscle fibres expressing fast myosin heavy chain (MyHC) isoforms, but in the two smallest mammalian species studied (mouse and rat), MND size was not larger in the fast-twitch fibres expressing the IIA MyHC isofom than in the slow-twitch type I fibres. In the larger mammals, the type I fibres always had the smallest average MND size, but contrary to mouse and rat muscles, type IIA fibres had lower mitochondrial enzyme activities than type I fibres. Myonuclear domain size was highly dependent on body mass in the two muscle fibre types expressed in all species, i.e. types I and IIA. Myonuclear domain size increased in muscle fibres expressing both the beta/slow (type I; r = 0.84, P fast IIA MyHC isoform (r = 0.90; P muscle fibre type, independent of species. However, myosin isoform expression is not the sole protein determining MND size, and other protein systems, such as mitochondrial proteins, may be equally or more important determinants of MND size.

Human skeletal muscle: transition between fast and slow fibre types.

Science.gov (United States)

Neunhäuserer, Daniel; Zebedin, Michaela; Obermoser, Magdalena; Moser, Gerhard; Tauber, Mark; Niebauer, Josef; Resch, Herbert; Galler, Stefan

2011-05-01

Human skeletal muscles consist of different fibre types: slow fibres (slow twitch or type I) containing the myosin heavy chain isoform (MHC)-I and fast fibres (fast twitch or type II) containing MHC-IIa (type IIA) or MHC-IId (type IID). The following order of decreasing kinetics is known: type IID > type IIA > type I. This order is especially based on the kinetics of stretch activation, which is the most discriminative property among fibre types. In this study we tested if hybrid fibres containing both MHC-IIa and MHC-I (type C fibres) provide a transition in kinetics between fast (type IIA) and slow fibres (type I). Our data of stretch activation kinetics suggest that type C fibres, with different ratios of MHC-IIa and MHC-I, do not provide a continuous transition. Instead, a specialized group of slow fibres, which we called "transition fibres", seems to provide a transition. Apart of their kinetics of stretch activation, which is most close to that of type IIA, the transition fibres are characterized by large cross-sectional areas and low maximal tensions. The molecular cause for the mechanical properties of the transition fibres is unknown. It is possible that the transition fibres contain an unknown slow MHC isoform, which cannot be separated by biochemical methods. Alternatively, or in addition, isoforms of myofibrillar proteins, other than MHC, and posttranslational modifications of myofibrillar proteins could play a role regarding the characteristics of the transition fibres.

Zinc-induced cardiomyocyte relaxation in a rat model of hyperglycemia is independent of myosin isoform

Directory of Open Access Journals (Sweden)

Yi Ting

2012-11-01

Full Text Available Abstract It has been reported previously that diabetic cardiomyopathy can be inhibited or reverted with chronic zinc supplementation. In the current study, we hypothesized that total cardiac calcium and zinc content is altered in early onset diabetes mellitus characterized in part as hyperglycemia (HG and that exposure of zinc ion (Zn2+ to isolated cardiomyocytes would enhance contraction-relaxation function in HG more so than in nonHG controls. To better control for differential cardiac myosin isoform expression as occurs in rodents after β-islet cell necrosis, hypothyroidism was induced in 16 rats resulting in 100% β-myosin heavy chain expression in the heart. β-Islet cell necrosis was induced in half of the rats by streptozocin administration. After 6 wks of HG, both HG and nonHG controls rats demonstrated similar myofilament performance measured as thin filament calcium sensitivity, native thin filament velocity in the myosin motility assay and contractile velocity and power. Extracellular Zn2+ reduced cardiomyocyte contractile function in both groups, but enhanced relaxation function significantly in the HG group compared to controls. Most notably, a reduction in diastolic sarcomere length with increasing pacing frequencies, i.e., incomplete relaxation, was more pronounced in the HG compared to controls, but was normalized with extracellular Zn2+ application. This is a novel finding implicating that the detrimental effect of HG on cardiomyocyte Ca2+ regulation can be amelioration by Zn2+. Among the many post-translational modifications examined, only phosphorylation of ryanodine receptor (RyR at S-2808 was significantly higher in HG compared to nonHG. We did not find in our hypothyroid rats any differentiating effects of HG on myofibrillar protein phosphorylation, lysine acetylation, O-linked N-acetylglucosamine and advanced glycated end-products, which are often implicated as complicating factors in cardiac performance due to HG. Our

Mathematical modeling of sleep state dynamics in a rodent model of shift work

Directory of Open Access Journals (Sweden)

Michael J. Rempe

2018-06-01

Full Text Available Millions of people worldwide are required to work when their physiology is tuned for sleep. By forcing wakefulness out of the body’s normal schedule, shift workers face numerous adverse health consequences, including gastrointestinal problems, sleep problems, and higher rates of some diseases, including cancers. Recent studies have developed protocols to simulate shift work in rodents with the intention of assessing the effects of night-shift work on subsequent sleep (Grønli et al., 2017. These studies have already provided important contributions to the understanding of the metabolic consequences of shift work (Arble et al., 2015; Marti et al., 2016; Opperhuizen et al., 2015 and sleep-wake-specific impacts of night-shift work (Grønli et al., 2017. However, our understanding of the causal mechanisms underlying night-shift-related sleep disturbances is limited. In order to advance toward a mechanistic understanding of sleep disruption in shift work, we model these data with two different approaches. First we apply a simple homeostatic model to quantify differences in the rates at which sleep need, as measured by slow wave activity during slow wave sleep (SWS rises and falls. Second, we develop a simple and novel mathematical model of rodent sleep and use it to investigate the timing of sleep in a simulated shift work protocol (Grønli et al., 2017. This mathematical framework includes the circadian and homeostatic processes of the two-process model, but additionally incorporates a stochastic process to model the polyphasic nature of rodent sleep. By changing only the time at which the rodents are forced to be awake, the model reproduces some key experimental results from the previous study, including correct proportions of time spent in each stage of sleep as a function of circadian time and the differences in total wake time and SWS bout durations in the rodents representing night-shift workers and those representing day-shift workers

Localization of Myosin and Actin in the Pelage and Whisker Hair Follicles of Rat

International Nuclear Information System (INIS)

Morioka, Kiyokazu; Matsuzaki, Toshiyuki; Takata, Kuniaki

2006-01-01

The combined effects of myosin II and actin enable muscle and nonmuscle cells to generate forces required for muscle contraction, cell division, cell migration, cellular morphological changes, the maintenance of cellular tension and polarity, and so on. However, except for the case of muscle contraction, the details are poorly understood. We focus on nonmuscle myosin and actin in the formation and maintenance of hair and skin, which include highly active processes in mammalian life with respect to the cellular proliferation, differentiation, and movement. The localization of nonmuscle myosin II and actin in neonatal rat dorsal skin, mystacial pad, hair follicles, and vibrissal follicles was studied by immunohistochemical technique to provide the basis for the elucidation of the roles of these proteins. Specificities of the antibodies were verified by using samples from the relevant tissues and subjecting them to immunoblotting test prior to morphological analyses. The myosin and actin were abundant and colocalized in the spinous and granular layers but scarce in the basal layer of the dorsal and mystacial epidermis. In hair and vibrissal follicles, nonmuscle myosin and actin were colocalized in the outer root sheath and some hair matrix cells adjoining dermal papillae. In contrast, most areas of the inner root sheath and hair matrix appeared to comprise very small amounts of myosin and actin. Hair shaft may comprise significant myosin during the course of its keratinization. These results suggest that the actin-myosin system plays a part in cell movement, differentiation, protection and other key functions of skin and hair cells

Reduction in beta-myosin heavy chains in stunned myocardium as assessed by nondenaturing gel electrophoresis.

Science.gov (United States)

Garcia, S C; Pomblum, V J; Gams, E; Rupp, H; Schipke, J D

2007-09-01

Myosin plays a key role in the structure and function of cardiac muscle. Three myosin isoenzymes (V(1), V(2), and V(3)) with different ATPase activities have been identified in mammalian ventricles based on their heavy chain constituents. The relative amount of myosin isoenzymes changes under physiological and pathological conditions. Until now, myosin isoenzymes have frequently been determined using either tube gel (nondenaturing) polyacrylamide gel electrophoresis (PAGE), or gradient or uniform sodium dodecyl sulfate (denaturing) PAGE. Both methods have disadvantages, e.g., a long running time. We developed, therefore, a uniform, nondenaturing PAGE with slab minigel format for analyzing the myosin isoenzymes in normoxic and stunned rabbit hearts. In normoxic hearts of adult rabbits, V(3) predominated over V(1) (46 vs 41%). In turn, in the stunned hearts, V(1) predominated over V(3) (70 vs 30%), and the heterodimeric V(2) was not anymore detectable. This alteration appears to result from a selective loss of myosin heavy chain (MHC)-beta. In parallel, the biochemical markers troponin I and creatine kinase were increased in the stunned hearts. We suggest that alterations of myosin isoenzymes in stunned myocardium can be monitored with native PAGE. The present analysis of myosin isoenzyme appears thus as a new tool for evaluating defects in MHC dimer formation in postischemic hearts.

Myosins 1 and 6, myosin light chain kinase, actin and microtubules cooperate during antibody-mediated internalisation and trafficking of membrane-expressed viral antigens in feline infectious peritonitis virus infected monocytes.

Science.gov (United States)

Dewerchin, Hannah L; Desmarets, Lowiese M; Noppe, Ytse; Nauwynck, Hans J

2014-02-12

Monocytes infected with feline infectious peritonitis virus, a coronavirus, express viral proteins in their plasma membranes. Upon binding of antibodies, these proteins are quickly internalised through a new clathrin- and caveolae-independent internalisation pathway. By doing so, the infected monocytes can escape antibody-dependent cell lysis. In the present study, we investigated which kinases and cytoskeletal proteins are of importance during internalisation and subsequent intracellular transport. The experiments showed that myosin light chain kinase (MLCK) and myosin 1 are crucial for the initiation of the internalisation. With co-localisation stainings, it was found that MLCK and myosin 1 co-localise with antigens even before internalisation started. Myosin 6 co-localised with the internalising complexes during passage through the cortical actin, were it might play a role in moving or disintegrating actin filaments, to overcome the actin barrier. One minute after internalisation started, vesicles had passed the cortical actin, co-localised with microtubules and association with myosin 6 was lost. The vesicles were further transported over the microtubules and accumulated at the microtubule organising centre after 10 to 30 min. Intracellular trafficking over microtubules was mediated by MLCK, myosin 1 and a small actin tail. Since inhibiting MLCK with ML-7 was so efficient in blocking the internalisation pathway, this target can be used for the development of a new treatment for FIPV.

Actin-myosin contractility is responsible for the reduced viability of dissociated human embryonic stem cells.

Science.gov (United States)

Chen, Guokai; Hou, Zhonggang; Gulbranson, Daniel R; Thomson, James A

2010-08-06

Human ESCs are the pluripotent precursor of the three embryonic germ layers. Human ESCs exhibit basal-apical polarity, junctional complexes, integrin-dependent matrix adhesion, and E-cadherin-dependent cell-cell adhesion, all characteristics shared by the epiblast epithelium of the intact mammalian embryo. After disruption of epithelial structures, programmed cell death is commonly observed. If individualized human ESCs are prevented from reattaching and forming colonies, their viability is significantly reduced. Here, we show that actin-myosin contraction is a critical effector of the cell death response to human ESC dissociation. Inhibition of myosin heavy chain ATPase, downregulation of myosin heavy chain, and downregulation of myosin light chain all increase survival and cloning efficiency of individualized human ESCs. ROCK inhibition decreases phosphorylation of myosin light chain, suggesting that inhibition of actin-myosin contraction is also the mechanism through which ROCK inhibitors increase cloning efficiency of human ESCs. Copyright 2010 Elsevier Inc. All rights reserved.

An isoform of myosin XI is responsible for the translocation of endoplasmic reticulum in tobacco cultured BY-2 cells.

Science.gov (United States)

Yokota, Etsuo; Ueda, Shunpei; Tamura, Kentaro; Orii, Hidefumi; Uchi, Satoko; Sonobe, Seiji; Hara-Nishimura, Ikuko; Shimmen, Teruo

2009-01-01

The involvement of myosin XI in generating the motive force for cytoplasmic streaming in plant cells is becoming evident. For a comprehensive understanding of the physiological roles of myosin XI isoforms, it is necessary to elucidate the properties and functions of each isoform individually. In tobacco cultured BY-2 cells, two types of myosins, one composed of 175 kDa heavy chain (175 kDa myosin) and the other of 170 kDa heavy chain (170 kDa myosin), have been identified biochemically and immunocytochemically. From sequence analyses of cDNA clones encoding heavy chains of 175 kDa and 170 kDa myosin, both myosins have been classified as myosin XI. Immunocytochemical studies using a polyclonal antibody against purified 175 kDa myosin heavy chain showed that the 175 kDa myosin is distributed throughout the cytoplasm as fine dots in interphase BY-2 cells. During mitosis, some parts of 175 kDa myosin were found to accumulate in the pre-prophase band (PPB), spindle, the equatorial plane of a phragmoplast and on the circumference of daughter nuclei. In transgenic BY-2 cells, in which an endoplasmic reticulum (ER)-specific retention signal, HDEL, tagged with green fluorescent protein (GFP) was stably expressed, ER showed a similar behaviour to that of 175 kDa myosin. Furthermore, this myosin was co-fractionated with GFP-ER by sucrose density gradient centrifugation. From these findings, it was suggested that the 175 kDa myosin is a molecular motor responsible for translocating ER in BY-2 cells.

Exploration of flexible phenylpropylurea scaffold as novel cardiac myosin activators for the treatment of systolic heart failure.

Science.gov (United States)

Manickam, Manoj; Jalani, Hitesh B; Pillaiyar, Thanigaimalai; Sharma, Niti; Boggu, Pulla Reddy; Venkateswararao, Eeda; Lee, You-Jung; Jeon, Eun-Seok; Jung, Sang-Hun

2017-07-07

A series of flexible urea derivatives have been synthesized and demonstrated as selective cardiac myosin ATPase activator. Among them 1-phenethyl-3-(3-phenylpropyl)urea (1, cardiac myosin ATPase activation at 10 μM = 51.1%; FS = 18.90; EF = 12.15) and 1-benzyl-3-(3-phenylpropyl)urea (9, cardiac myosin ATPase activation = 53.3%; FS = 30.04; EF = 18.27) showed significant activity in vitro and in vivo. The change of phenyl ring with tetrahydropyran-4-yl moiety viz., 1-(3-phenylpropyl)-3-((tetrahydro-2H-pyran-4-yl)methyl)urea (14, cardiac myosin ATPase activation = 81.4%; FS = 20.50; EF = 13.10), and morpholine moiety viz., 1-(2-morpholinoethyl)-3-(3-phenylpropyl)urea (21, cardiac myosin ATPase activation = 44.0%; FS = 24.79; EF = 15.65), proved to be efficient to activate the cardiac myosin. The potent compounds 1, 9, 14 and 21 were found to be selective for cardiac myosin over skeletal and smooth myosins. Thus, these urea derivatives are potent scaffold to develop as a newer cardiac myosin activator for the treatment of systolic heart failure. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Effects of hypothyroidism on myosin heavy chain composition and fibre types of fast skeletal muscles in a small marsupial, Antechinus flavipes.

Science.gov (United States)

Zhong, Wendy W H; Withers, Kerry W; Hoh, Joseph F Y

2010-04-01

Effects of drug-induced hypothyroidism on myosin heavy chain (MyHC) content and fibre types of fast skeletal muscles were studied in a small marsupial, Antechinus flavipes. SDS-PAGE of MyHCs from the tibialis anterior and gastrocnemius revealed four isoforms, 2B, 2X, 2A and slow, in that order of decreasing abundance. After 5 weeks treatment with methimazole, the functionally fastest 2B MyHC significantly decreased, while 2X, 2A and slow MyHCs increased. Immunohistochemistry using monospecific antibodies to each of the four MyHCs revealed decreased 2b and 2x fibres, and increased 2a and hybrid fibres co-expressing two or three MyHCs. In the normally homogeneously fast superficial regions of these muscles, evenly distributed slow-staining fibres appeared, resembling the distribution of slow primary myotubes in fast muscles during development. Hybrid fibres containing 2A and slow MyHCs were virtually absent. These results are more detailed but broadly similar to the earlier studies on eutherians. We hypothesize that hypothyroidism essentially reverses the effects of thyroid hormone on MyHC gene expression of muscle fibres during myogenesis, which differ according to the developmental origin of the fibre: it induces slow MyHC expression in 2b fibres derived from fast primary myotubes, and shifts fast MyHC expression in fibres of secondary origin towards 2A, but not slow, MyHC.

Immunogenicity and Protective Efficacy of Brugia malayi Heavy Chain Myosin as Homologous DNA, Protein and Heterologous DNA/Protein Prime Boost Vaccine in Rodent Model.

Directory of Open Access Journals (Sweden)

Jyoti Gupta

Full Text Available We earlier demonstrated the immunoprophylactic efficacy of recombinant heavy chain myosin (Bm-Myo of Brugia malayi (B. malayi in rodent models. In the current study, further attempts have been made to improve this efficacy by employing alternate approaches such as homologous DNA (pcD-Myo and heterologous DNA/protein prime boost (pcD-Myo+Bm-Myo in BALB/c mouse model. The gene bm-myo was cloned in a mammalian expression vector pcDNA 3.1(+ and protein expression was confirmed in mammalian Vero cell line. A significant degree of protection (79.2%±2.32 against L3 challenge in pcD-Myo+Bm-Myo immunized group was observed which was much higher than that exerted by Bm-Myo (66.6%±2.23 and pcD-Myo (41.6%±2.45. In the heterologous immunized group, the percentage of peritoneal leukocytes such as macrophages, neutrophils, B cells and T cells marginally increased and their population augmented further significantly following L3 challenge. pcD-Myo+Bm-Myo immunization elicited robust cellular and humoral immune responses as compared to pcD-Myo and Bm-Myo groups as evidenced by an increased accumulation of CD4+, CD8+ T cells and CD19+ B cells in the mouse spleen and activation of peritoneal macrophages. Though immunized animals produced antigen-specific IgG antibodies and isotypes, sera of mice receiving pcD-Myo+Bm-Myo or Bm-Myo developed much higher antibody levels than other groups and there was profound antibody-dependent cellular adhesion and cytotoxicity (ADCC to B. malayi infective larvae (L3. pcD-Myo+Bm-Myo as well as Bm-Myo mice generated a mixed T helper cell phenotype as evidenced by the production of both pro-inflammatory (IL-2, IFN-γ and anti-inflammatory (IL-4, IL-10 cytokines. Mice receiving pcD-Myo on contrary displayed a polarized pro-inflammatory immune response. The findings suggest that the priming of animals with DNA followed by protein booster generates heightened and mixed pro- and anti-inflammatory immune responses that are capable of

Dynamics of myosin II organization into contractile networks and fibers at the medial cell cortex

Science.gov (United States)

Nie, Wei

The cellular morphology of adhered cells depends crucially on the formation of a contractile meshwork of parallel and cross-linked stress fibers along the contacting surface. The motor activity and mini-filament assembly of non-muscle myosin II is an important component of cell-level cytoskeletal remodeling during mechanosensing. To monitor the dynamics of non-muscle myosin II, we used confocal microscopy to image cultured HeLa cells that stably express myosin regulatory light chain tagged with GFP (MRLC-GFP). MRLC-GFP was monitored in time-lapse movies at steady state and during the response of cells to varying concentrations of blebbistatin (which disrupts actomyosin stress fibers). Using image correlation spectroscopy analysis, we quantified the kinetics of disassembly and reassembly of actomyosin networks and compared to studies by other groups. This analysis suggested the following processes: myosin minifilament assembly and disassembly; aligning and contraction; myosin filament stabilization upon increasing contractile tension. Numerical simulations that include those processes capture some of the main features observed in the experiments. This study provides a framework to help interpret how different cortical myosin remodeling kinetics may contribute to different cell shape and rigidity depending on substrate stiffness. We discuss methods to monitor myosin reorganization using non-linear imaging methods.

Native myosin from adult rabbit skeletal muscle: isoenzymes and states of aggregation.

Science.gov (United States)

Morel, J E; D'hahan, N; Taouil, K; Francin, M; Aguilar, A; Dalbiez, J P; Merah, Z; Grussaute, H; Hilbert, B; Ollagnon, F; Selva, G; Piot, F

1998-04-21

The globular heads of skeletal muscle myosin have been shown to exist as isoenzymes S1 (A1) and S1 (A2), and there are also isoforms of the heavy chains. Using capillary electrophoresis, we found two dominant isoenzymes of the whole native myosin molecule, in agreement with what has previously been found by various techniques for native and nondenatured myosin from adult rabbits. Findings about possible states of aggregation of myosin and its heads are contradictory. By analytical ultracentrifugation, we confirmed the existence of a tail-tail dimer. By laser light scattering, we found a head-head dimer in the presence of MgATP. Capillary electrophoresis coupled with analytical ultracentrifugation and laser light scattering led us to refine these results. We found tail-tail dimers in a conventional buffer. We found tail-tail and head-head dimers in the presence of 0.5 mM MgATP and pure head-head dimers in the presence of 6 mM MgATP. All the dimers were homodimers. Naming the dominant isoenzymes of myosin a and b, we observed tail-tail dimers with isoenzyme a (TaTa) and with isoenzyme b (TbTb) and also head-head dimers with isoenzyme a (HaHa) and with isoenzyme b (HbHb).

Excessive Myosin Activity in Mbs Mutants Causes Photoreceptor Movement Out of the Drosophila Eye Disc Epithelium

OpenAIRE

Lee, Arnold; Treisman, Jessica E.

2004-01-01

Neuronal cells must extend a motile growth cone while maintaining the cell body in its original position. In migrating cells, myosin contraction provides the driving force that pulls the rear of the cell toward the leading edge. We have characterized the function of myosin light chain phosphatase, which down-regulates myosin activity, in Drosophila photoreceptor neurons. Mutations in the gene encoding the myosin binding subunit of this enzyme cause photoreceptors to drop out of the eye disc e...

Myosin light chain kinase regulates synaptic plasticity and fear learning in the lateral amygdala.

Science.gov (United States)

Lamprecht, R; Margulies, D S; Farb, C R; Hou, M; Johnson, L R; LeDoux, J E

2006-01-01

Learning and memory depend on signaling molecules that affect synaptic efficacy. The cytoskeleton has been implicated in regulating synaptic transmission but its role in learning and memory is poorly understood. Fear learning depends on plasticity in the lateral nucleus of the amygdala. We therefore examined whether the cytoskeletal-regulatory protein, myosin light chain kinase, might contribute to fear learning in the rat lateral amygdala. Microinjection of ML-7, a specific inhibitor of myosin light chain kinase, into the lateral nucleus of the amygdala before fear conditioning, but not immediately afterward, enhanced both short-term memory and long-term memory, suggesting that myosin light chain kinase is involved specifically in memory acquisition rather than in posttraining consolidation of memory. Myosin light chain kinase inhibitor had no effect on memory retrieval. Furthermore, ML-7 had no effect on behavior when the training stimuli were presented in a non-associative manner. Anatomical studies showed that myosin light chain kinase is present in cells throughout lateral nucleus of the amygdala and is localized to dendritic shafts and spines that are postsynaptic to the projections from the auditory thalamus to lateral nucleus of the amygdala, a pathway specifically implicated in fear learning. Inhibition of myosin light chain kinase enhanced long-term potentiation, a physiological model of learning, in the auditory thalamic pathway to the lateral nucleus of the amygdala. When ML-7 was applied without associative tetanic stimulation it had no effect on synaptic responses in lateral nucleus of the amygdala. Thus, myosin light chain kinase activity in lateral nucleus of the amygdala appears to normally suppress synaptic plasticity in the circuits underlying fear learning, suggesting that myosin light chain kinase may help prevent the acquisition of irrelevant fears. Impairment of this mechanism could contribute to pathological fear learning.

Calcium and cargoes as regulators of myosin 5a activity

International Nuclear Information System (INIS)

Sellers, James R.; Thirumurugan, Kavitha; Sakamoto, Takeshi; Hammer, John A.; Knight, Peter J.

2008-01-01

Myosin 5a is a two-headed actin-dependent motor that transports various cargoes in cells. Its enzymology and mechanochemistry have been extensively studied in vitro. It is a processive motor that takes multiple 36 nm steps on actin. The enzymatic activity of myosin 5 is regulated by an intramolecular folding mechanism whereby its lever arms fold back against the coiled-coil tail such that the motor domains directly bind the globular tail domains. We show that the structure seen in individual folded molecules is consistent with electron density map of two-dimensional crystals of the molecule. In this compact state, the actin-activated MgATPase activity of the molecule is markedly inhibited and the molecule cannot move processively on surface bound actin filaments. The actin-activated MgATPase activity of myosin 5a is activated by increasing the calcium concentration or by binding of a cargo-receptor molecule, melanophilin, in vitro. However, calcium binding to the calmodulin light chains results in dissociation of some of the calmodulin which disrupts the ability of myosin 5a to move on actin filaments in vitro. Thus we propose that the physiologically relevant activation pathway in vivo involves binding of cargo-receptor proteins

Smitin, a novel smooth muscle titin-like protein, interacts with myosin filaments in vivo and in vitro.

Science.gov (United States)

Kim, Kyoungtae; Keller, Thomas C S

2002-01-07

Smooth muscle cells use an actin-myosin II-based contractile apparatus to produce force for a variety of physiological functions, including blood pressure regulation and gut peristalsis. The organization of the smooth muscle contractile apparatus resembles that of striated skeletal and cardiac muscle, but remains much more poorly understood. We have found that avian vascular and visceral smooth muscles contain a novel, megadalton protein, smitin, that is similar to striated muscle titin in molecular morphology, localization in a contractile apparatus, and ability to interact with myosin filaments. Smitin, like titin, is a long fibrous molecule with a globular domain on one end. Specific reactivities of an anti-smitin polyclonal antibody and an anti-titin monoclonal antibody suggest that smitin and titin are distinct proteins rather than differentially spliced isoforms encoded by the same gene. Smitin immunofluorescently colocalizes with myosin in chicken gizzard smooth muscle, and interacts with two configurations of smooth muscle myosin filaments in vitro. In physiological ionic strength conditions, smitin and smooth muscle myosin coassemble into irregular aggregates containing large sidepolar myosin filaments. In low ionic strength conditions, smitin and smooth muscle myosin form highly ordered structures containing linear and polygonal end-to-end and side-by-side arrays of small bipolar myosin filaments. We have used immunogold localization and sucrose density gradient cosedimentation analyses to confirm association of smitin with both the sidepolar and bipolar smooth muscle myosin filaments. These findings suggest that the titin-like protein smitin may play a central role in organizing myosin filaments in the contractile apparatus and perhaps in other structures in smooth muscle cells.

Interaction of Myosin Phosphatase Target Subunit (MYPT1) with Myosin Phosphatase-RhoA Interacting Protein (MRIP): A Role of Glutamic Acids in the Interaction.

Science.gov (United States)

Lee, Eunhee; Stafford, Walter F

2015-01-01

Scaffold proteins bind to and functionally link protein members of signaling pathways. Interaction of the scaffold proteins, myosin phosphatase target subunit (MYPT1) and myosin phosphatase-RhoA interacting protein (MRIP), causes co-localization of myosin phosphatase and RhoA to actomyosin. To examine biophysical properties of interaction of MYPT1 with MRIP, we employed analytical ultracentrifugation and surface plasmon resonance. In regard to MRIP, its residues 724-837 are sufficient for the MYPT1/MRIP interaction. Moreover, MRIP binds to MYPT1 as either a monomer or a dimer. With respect to MYPT1, its leucine repeat region, LR (residues 991-1030) is sufficient to account for the MYPT1/MRIP interaction. Furthermore, point mutations that replace glutamic acids 998-1000 within LR reduced the binding affinity toward MRIP. This suggests that the glutamic acids of MYPT1 play an important role in the interaction.

Myosin-Powered Membrane Compartment Drives Cytoplasmic Streaming, Cell Expansion and Plant Development.

Science.gov (United States)

Peremyslov, Valera V; Cole, Rex A; Fowler, John E; Dolja, Valerian V

2015-01-01

Using genetic approaches, particle image velocimetry and an inert tracer of cytoplasmic streaming, we have made a mechanistic connection between the motor proteins (myosins XI), cargo transported by these motors (distinct endomembrane compartment defined by membrane-anchored MyoB receptors) and the process of cytoplasmic streaming in plant cells. It is shown that the MyoB compartment in Nicotiana benthamiana is highly dynamic moving with the mean velocity of ~3 μm/sec. In contrast, Golgi, mitochondria, peroxisomes, carrier vesicles and a cytosol flow tracer share distinct velocity profile with mean velocities of 0.6-1.5 μm/sec. Dominant negative inhibition of the myosins XI or MyoB receptors using overexpression of the N. benthamiana myosin cargo-binding domain or MyoB myosin-binding domain, respectively, resulted in velocity reduction for not only the MyoB compartment, but also each of the tested organelles, vesicles and cytoplasmic streaming. Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics. Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming. It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering. These results support a model according to which myosin-dependent, MyoB receptor-mediated transport of a specialized membrane compartment that is conserved in all land plants drives cytoplasmic streaming that carries organelles and vesicles and facilitates cell growth and plant development.

Urban resident attitudes toward rodents, rodent control products, and environmental effects

Science.gov (United States)

Rodent control in urban areas can result in the inadvertent mortality of non-target species (e.g., bobcats). However, there is little detailed information about rodent control practices of urban residents. Our objective was to evaluate urban rodent control behaviors in two area...

Electron Microscopic Recording of the Power and Recovery Strokes of Individual Myosin Heads Coupled with ATP Hydrolysis: Facts and Implications

Directory of Open Access Journals (Sweden)

Haruo Sugi

2018-05-01

Full Text Available The most straightforward way to get information on the performance of individual myosin heads producing muscle contraction may be to record their movement, coupled with ATP hydrolysis, electron-microscopically using the gas environmental chamber (EC. The EC enables us to visualize and record ATP-induced myosin head movement in hydrated skeletal muscle myosin filaments. When actin filaments are absent, myosin heads fluctuate around a definite neutral position, so that their time-averaged mean position remains unchanged. On application of ATP, myosin heads are found to move away from, but not towards, the bare region, indicating that myosin heads perform a recovery stroke (average amplitude, 6 nm. After exhaustion of ATP, myosin heads return to their neutral position. In the actin–myosin filament mixture, myosin heads form rigor actin myosin linkages, and on application of ATP, they perform a power stroke by stretching adjacent elastic structures because of a limited amount of applied ATP ≤ 10 µM. The average amplitude of the power stroke is 3.3 nm and 2.5 nm at the distal and the proximal regions of the myosin head catalytic domain (CAD, respectively. The power stroke amplitude increases appreciably at low ionic strength, which is known to enhance Ca2+-activated force in muscle. In both the power and recovery strokes, myosin heads return to their neutral position after exhaustion of ATP.

[Myosin B ATPase activity of the intestinal smooth muscle in intestinal obstruction].

Science.gov (United States)

Takamatsu, H

1983-06-01

Intestinal smooth myosin B was prepared from muscle layers around the lesion in dogs with experimental colonic stenosis and in patients with congenital intestinal obstruction. Mg2+-ATPase activity of the myosin B was compared between the proximal dilated segment and distal segment to obstruction. Experimental colonic stenosis: In early period after surgery, proximal colons showed higher activity of myosin B ATPase than distal colons, decreasing to less than distal colon as time passed. Congenital intestinal obstruction: In three cases, whose atresia might have occurred at earlier period of gestation, proximal bowels showed less activity of myosin B ATPase than distal bowels. However, in two cases, whose atresia might have occurred at later period of gestation, and two cases with intestinal stenosis, proximal bowels indicated higher activity of myosin B ATPase than distal bowels. These data suggested that the contractibility of the proximal intestine was depending on the duration of obstruction, and it was depressed in the former patients and was accelerated in the latter patients. These results suggested that the extensive resection of dilated proximal bowel in the congenital atresia is not always necessary to obtain good postoperative intestinal dynamics at the operation of the atresial lesions which may be induced at later period of gestation. They also suggested that surgery for intestinal obstruction should be performed before the depression of intestinal contractibility to get good bowel function.

Preparation and Characterization of Myosin Proteins.

Science.gov (United States)

Caldwell, Elizabeth; Eftink, Maurice R.

1985-01-01

Students complete five experimental projects at the end of a senior-level biochemistry course which involves the isolation and characterization of myosin and its water-soluble subfragments. Procedures used and results obtained are provided for such projects as viscosity and ATPase measurements and gel electrophoresis experiments. (JN)

The Role of a Novel Myosin Isoform in Prostate Cancer Metastasis

Science.gov (United States)

2013-10-01

2013 Accepted 14 February 2013 Available online 21 February 2013 Keywords: Myosin IC Isoforms Nucleolar localization signal Nucleolus Nucleus RNA...polymerase I Fibrillarinnt matter & 2013 Elsevier 1016/j.yexcr.2013.02.008 S, nucleolar localization ; No, nucleolus ; N, nucle bovine serum albumin; S...the nucleus, and the nucleolus . In the cytoplasm, myosin IC associ- ates with membranes and is involved in vesicle transport of membrane proteins [2

Auxotonic to isometric contraction transitioning in a beating heart causes myosin step-size to down shift.

Directory of Open Access Journals (Sweden)

Thomas P Burghardt

Full Text Available Myosin motors in cardiac ventriculum convert ATP free energy to the work of moving blood volume under pressure. The actin bound motor cyclically rotates its lever-arm/light-chain complex linking motor generated torque to the myosin filament backbone and translating actin against resisting force. Previous research showed that the unloaded in vitro motor is described with high precision by single molecule mechanical characteristics including unitary step-sizes of approximately 3, 5, and 8 nm and their relative step-frequencies of approximately 13, 50, and 37%. The 3 and 8 nm unitary step-sizes are dependent on myosin essential light chain (ELC N-terminus actin binding. Step-size and step-frequency quantitation specifies in vitro motor function including duty-ratio, power, and strain sensitivity metrics. In vivo, motors integrated into the muscle sarcomere form the more complex and hierarchically functioning muscle machine. The goal of the research reported here is to measure single myosin step-size and step-frequency in vivo to assess how tissue integration impacts motor function. A photoactivatable GFP tags the ventriculum myosin lever-arm/light-chain complex in the beating heart of a live zebrafish embryo. Detected single GFP emission reports time-resolved myosin lever-arm orientation interpreted as step-size and step-frequency providing single myosin mechanical characteristics over the active cycle. Following step-frequency of cardiac ventriculum myosin transitioning from low to high force in relaxed to auxotonic to isometric contraction phases indicates that the imposition of resisting force during contraction causes the motor to down-shift to the 3 nm step-size accounting for >80% of all the steps in the near-isometric phase. At peak force, the ATP initiated actomyosin dissociation is the predominant strain inhibited transition in the native myosin contraction cycle. The proposed model for motor down-shifting and strain sensing involves ELC N

Preparation of monoclonal antibodies against cardiac myosin and some radiolabelling studies

International Nuclear Information System (INIS)

Bapat, K.; Venkatesh, M.; Pillai, M.R.A.; Sarma, H.D.; Sainis, K.B.

1998-01-01

Monoclonal antibodies were raised against myosin, a specific indicator of myocardial infarction and labelled with 125 I and 99m Tc. Human cardiac myosin was isolated from normal human heart and was used for raising the monoclonal antibodies by the hybridoma technique. Antibody producing clones were identified by ELISA and cloning was done by the limiting dilution technique. Of the 13 clones obtained, 4 were deemed suitable for further studies. The antibodies were grown in ascites, purified, isotyped and their cross reactions with other forms of myosin were estimated. All the clones showed negligible cross reaction with rabbit myosin, but reacted to different extents with bovine skeletal myosin. The most avid antibody Mab-4G4 was chosen for further labelling studies. Mab-4G4 was labelled with 125 I using different oxidising agents such as iodogen, chloramine-T and lactoperoxidase. Purified radioiodinated antibody with radiochemical purity >95% could be obtained by gel filtration. Immunoreactivity was retained as tested by binding to myosin immobilised on a solid support. Mab-4G4 was also labelled with 99m Tc using stannous tartrate as the reducing agent. Radiolabelling yield was ∼60%, the purity was >95% and the immunoreactivity was retained. Both the labelled preparations were tested for bio-distribution in normal and infarcted rats. The activity accumulation in the infarcted region was ∼ 1.5 and 3.5 times as that in normal heart muscle for 125 I and 99m Tc labelled Mab-4G4 respectively. The major problem with the iodinated antibody was the in vivo deiodination resulting in very high percentage of activity in the thyroid. Although the fraction of the total activity associated with the infarcted heart is not very impressive, the fact that the activities with the infarcted and normal hearths are significantly different is heartening. With further optimisation of labelling and use of F(ab)'2 fragments, better delineation of the infarct sites is aspired. (author)

K-252a, a novel microbial product, inhibits smooth muscle myosin light chain kinase

International Nuclear Information System (INIS)

Nakanishi, S.; Yamada, K.; Kase, H.; Nakamura, S.; Nonomura, Y.

1988-01-01

Effects of K-252a, purified from the culture broth of Nocardiopsis sp., on the activity of myosin (light chain kinase were investigated. 1) K-252a affected three characteristic properties of chicken gizzard myosin-B, natural actomyosin, to a similar degree: the Ca 2+ -dependent activity of ATPase, superprecipitation, and the phosphorylation of the myosin light chain. 2) K-252a inhibited the activities of the purified myosin light chain kinase and a Ca 2+ -independent form of the enzyme which was constructed by cross-linking of myosin light chain kinase and calmodulin using glutaraldehyde. The degrees of inhibition by 3 x 10 -6 M K-252a were 69 and 48% of the control activities with the purified enzyme and the cross-linked complex, respectively. Chlorpromazine (3 x 10 -4 M), a calmodulin antagonist, inhibited the native enzyme, but not the cross-linked one. These results suggested that K-252a inhibited myosin light chain kinase by direct interaction with the enzyme, whereas chlorpromazine suppressed the enzyme activation by interacting with calmodulin. 3) The inhibition by K-252a of the cross-linked kinase was affected by the concentration of ATP, a phosphate donor. The concentration causing 50% inhibition was two orders magnitude lowere in the presence of 100 μM ATP than in the presence of 2 mM ATP. 4) Kinetic analyses using [γ- 32 P]ATP indicated that the inhibitory mode of K-252a was competitive with respect to ATP. These results suggest that K-252a interacts at the ATP-binding domain of myosin light chain kinase

The Effects of Hsp90α1 Mutations on Myosin Thick Filament Organization.

Science.gov (United States)

He, Qiuxia; Liu, Kechun; Tian, Zhenjun; Du, Shao Jun

2015-01-01

Heat shock protein 90α plays a key role in myosin folding and thick filament assembly in muscle cells. To assess the structure and function of Hsp90α and its potential regulation by post-translational modification, we developed a combined knockdown and rescue assay in zebrafish embryos to systematically analyze the effects of various mutations on Hsp90α function in myosin thick filament organization. DNA constructs expressing the Hsp90α1 mutants with altered putative ATP binding, phosphorylation, acetylation or methylation sites were co-injected with Hsp90α1 specific morpholino into zebrafish embryos. Myosin thick filament organization was analyzed in skeletal muscles of the injected embryos by immunostaining. The results showed that mutating the conserved D90 residue in the Hsp90α1 ATP binding domain abolished its function in thick filament organization. In addition, phosphorylation mimicking mutations of T33D, T33E and T87E compromised Hsp90α1 function in myosin thick filament organization. Similarly, K287Q acetylation mimicking mutation repressed Hsp90α1 function in myosin thick filament organization. In contrast, K206R and K608R hypomethylation mimicking mutations had not effect on Hsp90α1 function in thick filament organization. Given that T33 and T87 are highly conserved residues involved post-translational modification (PTM) in yeast, mouse and human Hsp90 proteins, data from this study could indicate that Hsp90α1 function in myosin thick filament organization is potentially regulated by PTMs involving phosphorylation and acetylation.

Stretch activates myosin light chain kinase in arterial smooth muscle

International Nuclear Information System (INIS)

Barany, K.; Rokolya, A.; Barany, M.

1990-01-01

Stretching of porcine carotid arterial muscle increased the phosphorylation of the 20 kDa myosin light chain from 0.23 to 0.68 mol [32P]phosphate/mol light chain, whereas stretching of phorbol dibutyrate treated muscle increased the phosphorylation from 0.30 to 0.91 mol/mol. Two-dimensional gel electrophoresis followed by two-dimensional tryptic phosphopeptide mapping was used to identify the enzyme involved in the stretch-induced phosphorylation. Quantitation of the [32P]phosphate content of the peptides revealed considerable light chain phosphorylation by protein kinase C only in the phorbol dibutyrate treated arterial muscle, whereas most of the light chain phosphorylation was attributable to myosin light chain kinase. Upon stretch of either the untreated or treated muscle, the total increment in [32P]phosphate incorporation into the light chain could be accounted for by peptides characteristic for myosin light chain kinase catalyzed phosphorylation, demonstrating that the stretch-induced phosphorylation is caused by this enzyme exclusively

Head-head interactions of resting myosin crossbridges in intact frog skeletal muscles, revealed by synchrotron x-ray fiber diffraction.

Directory of Open Access Journals (Sweden)

Kanji Oshima

Full Text Available The intensities of the myosin-based layer lines in the x-ray diffraction patterns from live resting frog skeletal muscles with full thick-thin filament overlap from which partial lattice sampling effects had been removed were analyzed to elucidate the configurations of myosin crossbridges around the thick filament backbone to nanometer resolution. The repeat of myosin binding protein C (C-protein molecules on the thick filaments was determined to be 45.33 nm, slightly longer than that of myosin crossbridges. With the inclusion of structural information for C-proteins and a pre-powerstroke head shape, modeling in terms of a mixed population of regular and perturbed regions of myosin crown repeats along the filament revealed that the myosin filament had azimuthal perturbations of crossbridges in addition to axial perturbations in the perturbed region, producing pseudo-six-fold rotational symmetry in the structure projected down the filament axis. Myosin crossbridges had a different organization about the filament axis in each of the regular and perturbed regions. In the regular region that lacks C-proteins, there were inter-molecular interactions between the myosin heads in axially adjacent crown levels. In the perturbed region that contains C-proteins, in addition to inter-molecular interactions between the myosin heads in the closest adjacent crown levels, there were also intra-molecular interactions between the paired heads on the same crown level. Common features of the interactions in both regions were interactions between a portion of the 50-kDa-domain and part of the converter domain of the myosin heads, similar to those found in the phosphorylation-regulated invertebrate myosin. These interactions are primarily electrostatic and the converter domain is responsible for the head-head interactions. Thus multiple head-head interactions of myosin crossbridges also characterize the switched-off state and have an important role in the regulation

Dual role for myosin II in GLUT4-mediated glucose uptake in 3T3-L1 adipocytes

International Nuclear Information System (INIS)

Fulcher, F. Kent; Smith, Bethany T.; Russ, Misty; Patel, Yashomati M.

2008-01-01

Insulin-stimulated glucose uptake requires the activation of several signaling pathways to mediate the translocation and fusion of GLUT4 vesicles to the plasma membrane. Our previous studies demonstrated that GLUT4-mediated glucose uptake is a myosin II-dependent process in adipocytes. The experiments described in this report are the first to show a dual role for the myosin IIA isoform specifically in regulating insulin-stimulated glucose uptake in adipocytes. We demonstrate that inhibition of MLCK but not RhoK results in impaired insulin-stimulated glucose uptake. Furthermore, our studies show that insulin specifically stimulates the phosphorylation of the RLC associated with the myosin IIA isoform via MLCK. In time course experiments, we determined that GLUT4 translocates to the plasma membrane prior to myosin IIA recruitment. We further show that recruitment of myosin IIA to the plasma membrane requires that myosin IIA be activated via phosphorylation of the RLC by MLCK. Our findings also reveal that myosin II is required for proper GLUT4-vesicle fusion at the plasma membrane. We show that once at the plasma membrane, myosin II is involved in regulating the intrinsic activity of GLUT4 after insulin stimulation. Collectively, our results are the first to reveal that myosin IIA plays a critical role in mediating insulin-stimulated glucose uptake in 3T3-LI adipocytes, via both GLUT4 vesicle fusion at the plasma membrane and GLUT4 activity

Myosin X is recruited to nascent focal adhesions at the leading edge and induces multi-cycle filopodial elongation.

Science.gov (United States)

He, Kangmin; Sakai, Tsuyoshi; Tsukasaki, Yoshikazu; Watanabe, Tomonobu M; Ikebe, Mitsuo

2017-10-20

Filopodia protrude from the leading edge of cells and play important roles in cell motility. Here we report the mechanism of myosin X (encoded by Myo10)-induced multi-cycle filopodia extension. We found that actin, Arp2/3, vinculin and integrin-β first accumulated at the cell's leading edge. Myosin X was then gathered at these sites, gradually clustered by lateral movement, and subsequently initiated filopodia formation. During filopodia extension, we found the translocation of Arp2/3 and integrin-β along filopodia. Arp2/3 and integrin-β then became localized at the tip of filopodia, from where myosin X initiated the second extension of filopodia with a change in extension direction, thus producing long filopodia. Elimination of integrin-β, Arp2/3 and vinculin by siRNA significantly attenuated the myosin-X-induced long filopodia formation. We propose the following mechanism. Myosin X accumulates at nascent focal adhesions at the cell's leading edge, where myosin X promotes actin convergence to create the base of filopodia. Then myosin X moves to the filopodia tip and attracts integrin-β and Arp2/3 for further actin nucleation. The tip-located myosin X then initiates the second cycle of filopodia elongation to produce the long filopodia.

Direct photoaffinity labeling by nucleotides of the apparent catalytic site on the heavy chains of smooth muscle and Acanthamoeba myosins

International Nuclear Information System (INIS)

Maruta, H.; Korn, E.D.

1981-01-01

The heavy chains of Acanthamoeba myosins, IA, IB and II, turkey gizzard myosin, and rabbit skeletal muscle myosin subfragment-1 were specifically labeled by radioactive ATP, ADP, and UTP, each of which is a substrate or product of myosin ATPase activity, when irradiated with uv light at 0 0 C. With UTP, as much as 0.45 mol/mol of Acanthamoeba myosin IA heavy chain and 1 mol/mol of turkey gizzard myosin heavy chain was incorporated. Evidence that the ligands were associated with the catalytic site included the observations that reaction occurred only with nucleotides that are substrates or products of the ATPase activity; that the reaction was blocked by pyrophosphate which is an inhibitor of the ATPase activity; that ATP was bound as ADP; and that label was probably restricted to a single peptide following limited subtilisin proteolysis of labeled Acanthamoeba myosin IA heavy chain and extensive cleavage with CNBr and trypsin of labeled turkey gizzard myosin heavy chain

Myosins and DYNLL1/LC8 in the honey bee (Apis mellifera L.) brain.

Science.gov (United States)

Calábria, Luciana Karen; Peixoto, Pablo Marco Veras; Passos Lima, Andreia Barcelos; Peixoto, Leonardo Gomes; de Moraes, Viviane Rodrigues Alves; Teixeira, Renata Roland; Dos Santos, Claudia Tavares; E Silva, Letícia Oliveira; da Silva, Maria de Fátima Rodrigues; dos Santos, Ana Alice Diniz; Garcia-Cairasco, Norberto; Martins, Antônio Roberto; Espreafico, Enilza Maria; Espindola, Foued Salmen

2011-09-01

Honey bees have brain structures with specialized and developed systems of communication that account for memory, learning capacity and behavioral organization with a set of genes homologous to vertebrate genes. Many microtubule- and actin-based molecular motors are involved in axonal/dendritic transport. Myosin-Va is present in the honey bee Apis mellifera nervous system of the larvae and adult castes and subcastes. DYNLL1/LC8 and myosin-IIb, -VI and -IXb have also been detected in the adult brain. SNARE proteins, such as CaMKII, clathrin, syntaxin, SNAP25, munc18, synaptophysin and synaptotagmin, are also expressed in the honey bee brain. Honey bee myosin-Va displayed ATP-dependent solubility and was associated with DYNLL1/LC8 and SNARE proteins in the membrane vesicle-enriched fraction. Myosin-Va expression was also decreased after the intracerebral injection of melittin and NMDA. The immunolocalization of myosin-Va and -IV, DYNLL1/LC8, and synaptophysin in mushroom bodies, and optical and antennal lobes was compared with the brain morphology based on Neo-Timm histochemistry and revealed a distinct and punctate distribution. This result suggested that the pattern of localization is associated with neuron function. Therefore, our data indicated that the roles of myosins, DYNLL1/LC8, and SNARE proteins in the nervous and visual systems of honey bees should be further studied under different developmental, caste and behavioral conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Molecular cloning and complete nucleotide sequence of a human ventricular myosin light chain 1

Energy Technology Data Exchange (ETDEWEB)

Hoffmann, E; Shi, Q W; Floroff, M; Mickle, D A.G.; Wu, T W; Olley, P M; Jackowski, G

1988-03-25

Human ventricular plasmid library was constructed. The library was screened with the oligonucleotide probe (17-mer) corresponding to a conserve region of myosin light chain 1 near the carboxy terminal. Full length cDNA recombinant plasmid containing 1100 bp insert was isolated. RNA blot hybridization with this insert detected a message of approximately 1500 bp corresponding to the size of VLCl and mRNA. Complete nucleotide sequence of the coding region was determined in M13 subclones using dideoxy chain termination method. With the isolation of this clone (pCD HLVCl), the publication of the complete nucleotide sequence of HVLCl and the predicted secondary structure of this protein will aid in understanding of the biochemistry of myosin and its function in contraction, the evolution of myosin light genes and the genetic, developmental and physiological regulation of myosin genes.

The fungal myosin I is essential for Fusarium toxisome formation.

Directory of Open Access Journals (Sweden)

Guangfei Tang

2018-01-01

Full Text Available Myosin-I molecular motors are proposed to function as linkers between membranes and the actin cytoskeleton in several cellular processes, but their role in the biosynthesis of fungal secondary metabolites remain elusive. Here, we found that the myosin I of Fusarium graminearum (FgMyo1, the causal agent of Fusarium head blight, plays critical roles in mycotoxin biosynthesis. Inhibition of myosin I by the small molecule phenamacril leads to marked reduction in deoxynivalenol (DON biosynthesis. FgMyo1 also governs translation of the DON biosynthetic enzyme Tri1 by interacting with the ribosome-associated protein FgAsc1. Disruption of the ATPase activity of FgMyo1 either by the mutation E420K, down-regulation of FgMyo1 expression or deletion of FgAsc1 results in reduced Tri1 translation. The DON biosynthetic enzymes Tri1 and Tri4 are mainly localized to subcellular structures known as toxisomes in response to mycotoxin induction and the FgMyo1-interacting protein, actin, participates in toxisome formation. The actin polymerization disruptor latrunculin A inhibits toxisome assembly. Consistent with this observation, deletion of the actin-associated proteins FgPrk1 and FgEnd3 also results in reduced toxisome formation. Unexpectedly, the FgMyo1-actin cytoskeleton is not involved in biosynthesis of another secondary metabolite tested. Taken together, this study uncovers a novel function of myosin I in regulating mycotoxin biosynthesis in filamentous fungi.

The fungal myosin I is essential for Fusarium toxisome formation.

Science.gov (United States)

Tang, Guangfei; Chen, Yun; Xu, Jin-Rong; Kistler, H Corby; Ma, Zhonghua

2018-01-01

Myosin-I molecular motors are proposed to function as linkers between membranes and the actin cytoskeleton in several cellular processes, but their role in the biosynthesis of fungal secondary metabolites remain elusive. Here, we found that the myosin I of Fusarium graminearum (FgMyo1), the causal agent of Fusarium head blight, plays critical roles in mycotoxin biosynthesis. Inhibition of myosin I by the small molecule phenamacril leads to marked reduction in deoxynivalenol (DON) biosynthesis. FgMyo1 also governs translation of the DON biosynthetic enzyme Tri1 by interacting with the ribosome-associated protein FgAsc1. Disruption of the ATPase activity of FgMyo1 either by the mutation E420K, down-regulation of FgMyo1 expression or deletion of FgAsc1 results in reduced Tri1 translation. The DON biosynthetic enzymes Tri1 and Tri4 are mainly localized to subcellular structures known as toxisomes in response to mycotoxin induction and the FgMyo1-interacting protein, actin, participates in toxisome formation. The actin polymerization disruptor latrunculin A inhibits toxisome assembly. Consistent with this observation, deletion of the actin-associated proteins FgPrk1 and FgEnd3 also results in reduced toxisome formation. Unexpectedly, the FgMyo1-actin cytoskeleton is not involved in biosynthesis of another secondary metabolite tested. Taken together, this study uncovers a novel function of myosin I in regulating mycotoxin biosynthesis in filamentous fungi.

Phosphorylated peptides occur in a non-helical portion of the tail of a catch muscle myosin

International Nuclear Information System (INIS)

Castellani, L.; Elliott, B.W. Jr.; Cohen, C.

1987-01-01

Myosin from a molluscan catch muscle (the Anterior Byssus Retractor (ABRM) of Mytilus edulis) is unusual in being phosphorylated in the rod by an endogenous heavy-chain kinase. This phosphorylation enhances myosin solubility at low ionic strength and induces molecular folding of the myosin tail. Papain and chymotryptic cleavage of this myosin, phosphorylated with [γ- 32 P]ATP, indicates that the phosphorylated residues are associated with the carboxy-terminal end of the light meromyosin. Ion-exchange and reverse-phase HPLC of radiolabeled chymotryptic peptides allow the isolation of two different peptides with high specific activity. One of these peptides is rich in lysine and arginine residues, a finding consistent with the observation that basic residues often determine the substrate specificity of protein kinases. The second peptide contains proline residues. Taken together, these results suggest that, as in the case of Acanthamoeba myosin, phosphorylation occurs in a nonhelical portion of the rod that may also control solubility. Identification of the residues that are phosphorylated and their location in the rod may reveal how the phosphorylation-dependent changes observed in the myosin in vitro are related to changes in intermolecular interactions in the thick filaments in vivo

Supplementation with 0.1% and 2% vitamin e in diabetic rats: analysis of myenteric neurons immunostained for myosin-V and nNOS in the jejunum

Directory of Open Access Journals (Sweden)

Eleandro Aparecido Tronchini

2012-12-01

Full Text Available CONTEXT: Diabetes mellitus is a disease characterized by hyperglycemia that, when allowed to progress long-term untreated, develops vascular and neurological complications, which are responsible for the development of alterations in the enteric nervous system in diabetic patients. In the gastrointestinal tract, diabetes mellitus promotes motor and sensory changes, and in the reflex function of this system, causing gastroparesis, diarrhea, constipation, megacolon, slow gastrointestinal transit, gastric stasis and dilation with decreased or increased peristaltic contractions. Several studies have shown that oxidative stress is the main responsible for the vascular and neurological complications affecting the enteric nervous system of diabetics. OBJECTIVE: The effects of 0.1% and 2% vitamin E on myosin-V- and nNOS-immunoreactive neurons in the jejunum of diabetic rats were investigated. METHODS: Thirty rats were divided into the groups: normoglycemic, normoglycemic treated with 0.1% vitamin E, normoglycemic treated with 2% vitamin E, diabetic, diabetic treated with 0.1% vitamin E, and diabetic treated with 2% vitamin E. The neuronal density and areas of neuron cell bodies were determined. RESULTS: Diabetes (diabetic group significantly reduced the number of myosin-V-immunoreactive neurons compared with the normoglycemic group. The diabetic treated with 0.1% vitamin E and diabetic treated with 2% vitamin E groups did not exhibit a greater density than the D group (P>0.05. Nitrergic density did not change with diabetes (P>0.05. The areas of myosin-V- and nNOS-immunoreactive neurons significantly increased in the normoglycemic treated with 2% vitamin E and diabetic groups compared with the normoglycemic group. CONCLUSION: Supplementation with 2% vitamin E had a neurotrophic effect only in the area of myosin-V-immunoreactive neurons compared with the diabetic group.

Myosin-1A Targets to Microvilli Using Multiple Membrane Binding Motifs in the Tail Homology 1 (TH1) Domain*

Science.gov (United States)

Mazerik, Jessica N.; Tyska, Matthew J.

2012-01-01

One of the most abundant components of the enterocyte brush border is the actin-based monomeric motor, myosin-1a (Myo1a). Within brush border microvilli, Myo1a carries out a number of critical functions at the interface between membrane and actin cytoskeleton. Proper physiological function of Myo1a depends on its ability to bind to microvillar membrane, an interaction mediated by a C-terminal tail homology 1 (TH1) domain. However, little is known about the mechanistic details of the Myo1a-TH1/membrane interaction. Structure-function analysis of Myo1a-TH1 targeting in epithelial cells revealed that an N-terminal motif conserved among class I myosins and a C-terminal motif unique to Myo1a-TH1 are both required for steady state microvillar enrichment. Purified Myo1a bound to liposomes composed of phosphatidylserine and phosphoinositol 4,5-bisphosphate, with moderate affinity in a charge-dependent manner. Additionally, peptides of the N- and C-terminal regions required for targeting were able to compete with Myo1a for binding to highly charged liposomes in vitro. Single molecule total internal reflection fluorescence microscopy showed that these motifs are also necessary for slowing the membrane detachment rate in cells. Finally, Myo1a-TH1 co-localized with both lactadherin-C2 (a phosphatidylserine-binding protein) and PLCδ1-PH (a phosphoinositol 4,5-bisphosphate-binding protein) in microvilli, but only lactaderin-C2 expression reduced brush border targeting of Myo1a-TH1. Together, our results suggest that Myo1a targeting to microvilli is driven by membrane binding potential that is distributed throughout TH1 rather than localized to a single motif. These data highlight the diversity of mechanisms that enable different class I myosins to target membranes in distinct biological contexts. PMID:22367206

Multidimensional structure-function relationships in human β-cardiac myosin from population-scale genetic variation

NARCIS (Netherlands)

Homburger, J.R. (Julian R.); Green, E.M. (Eric M.); Caleshu, C. (Colleen); Sunitha, M.S. (Margaret S.); Taylor, R.E. (Rebecca E.); Ruppel, K.M. (Kathleen M.); Metpally, R.P.R. (Raghu Prasad Rao); S.D. Colan (Steven); M. Michels (Michelle); Day, S.M. (Sharlene M.); I. Olivotto (Iacopo); Bustamante, C.D. (Carlos D.); Dewey, F.E. (Frederick E.); Ho, C.Y. (Carolyn Y.); Spudich, J.A. (James A.); Ashley, E.A. (Euan A.)

2016-01-01

textabstractMyosin motors are the fundamental force-generating elements of muscle contraction. Variation in the human β-cardiac myosin heavy chain gene (MYH7) can lead to hypertrophic cardiomyopathy (HCM), a heritable disease characterized by cardiac hypertrophy, heart failure, and sudden cardiac

Myosin isoform determines the conformational dynamics and cooperativity of actin filaments in the strongly bound actomyosin complex

Science.gov (United States)

Prochniewicz, Ewa; Chin, Harvey F.; Henn, Arnon; Hannemann, Diane E.; Olivares, Adrian O.; Thomas, David D.; De La Cruz, Enrique M.

2010-01-01

SUMMARY We have used transient phosphorescence anisotropy (TPA) to detect the microsecond rotational dynamics of erythrosin iodoacetamide (ErIA)-labeled actin strongly bound to single-headed fragments of muscle myosin (muscle S1) and non-muscle myosin V (MV). The conformational dynamics of actin filaments in solution are markedly influenced by the isoform of bound myosin. Both myosins increase the final anisotropy of actin at sub-stoichiometric binding densities, indicating long-range, non-nearest neighbor cooperative restriction of filament rotational dynamics amplitude, but the cooperative unit is larger with MV than muscle S1. Both myosin isoforms also cooperatively affect the actin filament rotational correlation time, but with opposite effects; muscle S1 decreases rates of intrafilament torsional motion, while binding of MV increases the rates of motion. The cooperative effects on the rates of intrafilament motions correlate with the kinetics of myosin binding to actin filaments such that MV binds more rapidly, and muscle myosin more slowly, to partially decorated filaments than to bare filaments. The two isoforms also differ in their effects on the phosphorescence lifetime of the actin-bound ErIA; while muscle S1 increases the lifetime, suggesting decreased aqueous exposure of the probe, MV does not induce a significant change. We conclude that the dynamics and structure of actin in the strongly bound actomyosin complex is determined by the isoform of the bound myosin, in a manner likely to accommodate the diverse functional roles of actomyosin in muscle and non-muscle cells. PMID:19962990

Mouse nuclear myosin I knock-out shows interchangeability and redundancy of myosin isoforms in the cell nucleus.

Science.gov (United States)

Venit, Tomáš; Dzijak, Rastislav; Kalendová, Alžběta; Kahle, Michal; Rohožková, Jana; Schmidt, Volker; Rülicke, Thomas; Rathkolb, Birgit; Hans, Wolfgang; Bohla, Alexander; Eickelberg, Oliver; Stoeger, Tobias; Wolf, Eckhard; Yildirim, Ali Önder; Gailus-Durner, Valérie; Fuchs, Helmut; de Angelis, Martin Hrabě; Hozák, Pavel

2013-01-01

Nuclear myosin I (NM1) is a nuclear isoform of the well-known "cytoplasmic" Myosin 1c protein (Myo1c). Located on the 11(th) chromosome in mice, NM1 results from an alternative start of transcription of the Myo1c gene adding an extra 16 amino acids at the N-terminus. Previous studies revealed its roles in RNA Polymerase I and RNA Polymerase II transcription, chromatin remodeling, and chromosomal movements. Its nuclear localization signal is localized in the middle of the molecule and therefore directs both Myosin 1c isoforms to the nucleus. In order to trace specific functions of the NM1 isoform, we generated mice lacking the NM1 start codon without affecting the cytoplasmic Myo1c protein. Mutant mice were analyzed in a comprehensive phenotypic screen in cooperation with the German Mouse Clinic. Strikingly, no obvious phenotype related to previously described functions has been observed. However, we found minor changes in bone mineral density and the number and size of red blood cells in knock-out mice, which are most probably not related to previously described functions of NM1 in the nucleus. In Myo1c/NM1 depleted U2OS cells, the level of Pol I transcription was restored by overexpression of shRNA-resistant mouse Myo1c. Moreover, we found Myo1c interacting with Pol II. The ratio between Myo1c and NM1 proteins were similar in the nucleus and deletion of NM1 did not cause any compensatory overexpression of Myo1c protein. We observed that Myo1c can replace NM1 in its nuclear functions. Amount of both proteins is nearly equal and NM1 knock-out does not cause any compensatory overexpression of Myo1c. We therefore suggest that both isoforms can substitute each other in nuclear processes.

A novel role for myosin II in insulin-stimulated glucose uptake in 3T3-L1 adipocytes

International Nuclear Information System (INIS)

Steimle, Paul A.; Kent Fulcher, F.; Patel, Yashomati M.

2005-01-01

Insulin-stimulated glucose uptake requires the activation of several signaling pathways to mediate the translocation and fusion of GLUT4 vesicles from an intracellular pool to the plasma membrane. The studies presented here show that inhibition of myosin II activity impairs GLUT4-mediated glucose uptake but not GLUT4 translocation to the plasma membrane. We also show that adipocytes express both myosin IIA and IIB isoforms, and that myosin IIA is recruited to the plasma membrane upon insulin stimulation. Taken together, the data presented here represent the first demonstration that GLUT4-mediated glucose uptake is a myosin II-dependent process in adipocytes. Based on our findings, we hypothesize that myosin II is activated upon insulin stimulation and recruited to the cell cortex to facilitate GLUT4 fusion with the plasma membrane. The identification of myosin II as a key component of GLUT4-mediated glucose uptake represents an important advance in our understanding of the mechanisms regulating glucose homeostasis

Myosin-II sets the optimal response time scale of chemotactic amoeba

Science.gov (United States)

Hsu, Hsin-Fang; Westendorf, Christian; Tarantola, Marco; Bodenschatz, Eberhard; Beta, Carsten

2014-03-01

The response dynamics of the actin cytoskeleton to external chemical stimuli plays a fundamental role in numerous cellular functions. One of the key players that governs the dynamics of the actin network is the motor protein myosin-II. Here we investigate the role of myosin-II in the response of the actin system to external stimuli. We used a microfluidic device in combination with a photoactivatable chemoattractant to apply stimuli to individual cells with high temporal resolution. We directly compare the actin dynamics in Dictyostelium discodelium wild type (WT) cells to a knockout mutant that is deficient in myosin-II (MNL). Similar to the WT a small population of MNL cells showed self-sustained oscillations even in absence of external stimuli. The actin response of MNL cells to a short pulse of chemoattractant resembles WT during the first 15 sec but is significantly delayed afterward. The amplitude of the dominant peak in the power spectrum from the response time series of MNL cells to periodic stimuli with varying period showed a clear resonance peak at a forcing period of 36 sec, which is significantly delayed as compared to the resonance at 20 sec found for the WT. This shift indicates an important role of myosin-II in setting the response time scale of motile amoeba. Institute of Physics und Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.

Engineering Circular Gliding of Actin Filaments Along Myosin-Patterned DNA Nanotube Rings To Study Long-Term Actin-Myosin Behaviors.

Science.gov (United States)

Hariadi, Rizal F; Appukutty, Abhinav J; Sivaramakrishnan, Sivaraj

2016-09-27

Nature has evolved molecular motors that are critical in cellular processes occurring over broad time scales, ranging from seconds to years. Despite the importance of the long-term behavior of molecular machines, topics such as enzymatic lifetime are underexplored due to the lack of a suitable approach for monitoring motor activity over long time periods. Here, we developed an "O"-shaped Myosin Empowered Gliding Assay (OMEGA) that utilizes engineered micron-scale DNA nanotube rings with precise arrangements of myosin VI to trap gliding actin filaments. This circular gliding assay platform allows the same individual actin filament to glide over the same myosin ensemble (50-1000 motors per ring) multiple times. First, we systematically characterized the formation of DNA nanotubes rings with 4, 6, 8, and 10 helix circumferences. Individual actin filaments glide along the nanotube rings with high processivity for up to 12.8 revolutions or 11 min in run time. We then show actin gliding speed is robust to variation in motor number and independent of ring curvature within our sample space (ring diameter of 0.5-4 μm). As a model application of OMEGA, we then analyze motor-based mechanical influence on "stop-and-go" gliding behavior of actin filaments, revealing that the stop-to-go transition probability is dependent on motor flexibility. Our circular gliding assay may provide a closed-loop platform for monitoring long-term behavior of broad classes of molecular motors and enable characterization of motor robustness and long time scale nanomechanical processes.

Tetranectin in slow intra- and extrafusal chicken muscle fibers

DEFF Research Database (Denmark)

Xu, X; Gilpin, B; Iba, K

2001-01-01

Tetranectin is a C-type lectin that occurs in the mammalian musculoskeletal system. In the present report we describe the first studies on an avian tetranectin. A full-length chicken tetranectin cDNA was isolated. Comparison of the deduced amino acid sequence of chicken tetranectin with mouse...... and human tetranectin showed an identity of 67 and 68%, respectively. Northern blot analysis demonstrated broad expression of chicken tetranectin mRNA, which was first detected on embryonic day 4. Tetranectin protein was detected in chicken serum and egg yolk. Since muscle is one of few tissues in which...... tetranectin protein is retained, we examined the distribution of tetranectin in various muscle types in chicken. Myofibers strongly positive for tetranectin were observed in several muscles including m. tibialis ant. and m. sartorius (from embryonic day 10 to adult). Using antibodies to fast and slow myosin...

Selective expression of the type 3 isoform of ryanodine receptor Ca2+ release channel (RyR3) in a subset of slow fibers in diaphragm and cephalic muscles of adult rabbits

International Nuclear Information System (INIS)

Conti, Antonio; Reggiani, Carlo; Sorrentino, Vincenzo

2005-01-01

The expression pattern of the RyR3 isoform of Ca 2+ release channels was analysed by Western blot in neonatal and adult rabbit skeletal muscles. The results obtained show that the expression of the RyR3 isoform is developmentally regulated. In fact, RyR3 expression was detected in all muscles analysed at 2 and 15 days after birth while, in adult animals, it was restricted to a subset of muscles that includes diaphragm, masseter, pterygoideus, digastricus, and tongue. Interestingly, all of these muscles share a common embryonic origin being derived from the somitomeres or from the cephalic region of the embryo. Immunofluorescence analysis of rabbit skeletal muscle cross-sections showed that RyR3 staining was detected in all fibers of neonatal muscles. In contrast, in those adult muscles expressing RyR3 only a fraction of fibers was labelled. Staining of these muscles with antibodies against fast and slow myosins revealed a close correlation between expression of RyR3 and fibers expressing slow myosin isoform

Interaction of c-Cbl with myosin IIA regulates Bleb associated macropinocytosis of Kaposi's sarcoma-associated herpesvirus.

Directory of Open Access Journals (Sweden)

Mohanan Valiya Veettil

2010-12-01

Full Text Available KSHV is etiologically associated with Kaposi's sarcoma (KS, an angioproliferative endothelial cell malignancy. Macropinocytosis is the predominant mode of in vitro entry of KSHV into its natural target cells, human dermal microvascular endothelial (HMVEC-d cells. Although macropinocytosis is known to be a major route of entry for many viruses, the molecule(s involved in the recruitment and integration of signaling early during macropinosome formation is less well studied. Here we demonstrate that tyrosine phosphorylation of the adaptor protein c-Cbl is required for KSHV induced membrane blebbing and macropinocytosis. KSHV induced the tyrosine phosphorylation of c-Cbl as early as 1 min post-infection and was recruited to the sites of bleb formation. Infection also led to an increase in the interaction of c-Cbl with PI3-K p85 in a time dependent manner. c-Cbl shRNA decreased the formation of KSHV induced membrane blebs and macropinocytosis as well as virus entry. Immunoprecipitation of c-Cbl followed by mass spectrometry identified the interaction of c-Cbl with a novel molecular partner, non-muscle myosin heavy chain IIA (myosin IIA, in bleb associated macropinocytosis. Phosphorylated c-Cbl colocalized with phospho-myosin light chain II in the interior of blebs of infected cells and this interaction was abolished by c-Cbl shRNA. Studies with the myosin II inhibitor blebbistatin demonstrated that myosin IIA is a biologically significant component of the c-Cbl signaling pathway and c-Cbl plays a new role in the recruitment of myosin IIA to the blebs during KSHV infection. Myosin II associates with actin in KSHV induced blebs and the absence of actin and myosin ubiquitination in c-Cbl ShRNA cells suggested that c-Cbl is also responsible for the ubiquitination of these proteins in the infected cells. This is the first study demonstrating the role of c-Cbl in viral entry as well as macropinocytosis, and provides the evidence that a signaling complex

Selective expression of myosin IC Isoform A in mouse and human cell lines and mouse prostate cancer tissues.

Directory of Open Access Journals (Sweden)

Ivanna Ihnatovych

Full Text Available Myosin IC is a single headed member of the myosin superfamily. We recently identified a novel isoform and showed that the MYOIC gene in mammalian cells encodes three isoforms (isoforms A, B, and C. Furthermore, we demonstrated that myosin IC isoform A but not isoform B exhibits a tissue specific expression pattern. In this study, we extended our analysis of myosin IC isoform expression patterns by analyzing the protein and mRNA expression in various mammalian cell lines and in various prostate specimens and tumor tissues from the transgenic mouse prostate (TRAMP model by immunoblotting, qRT-PCR, and by indirect immunohistochemical staining of paraffin embedded prostate specimen. Analysis of a panel of mammalian cell lines showed an increased mRNA and protein expression of specifically myosin IC isoform A in a panel of human and mouse prostate cancer cell lines but not in non-cancer prostate or other (non-prostate- cancer cell lines. Furthermore, we demonstrate that myosin IC isoform A expression is significantly increased in TRAMP mouse prostate samples with prostatic intraepithelial neoplasia (PIN lesions and in distant site metastases in lung and liver when compared to matched normal tissues. Our observations demonstrate specific changes in the expression of myosin IC isoform A that are concurrent with the occurrence of prostate cancer in the TRAMP mouse prostate cancer model that closely mimics clinical prostate cancer. These data suggest that elevated levels of myosin IC isoform A may be a potential marker for the detection of prostate cancer.

Myosin isoform switching during assembly of the Drosophila flight muscle thick filament lattice.

Science.gov (United States)

Orfanos, Zacharias; Sparrow, John C

2013-01-01

During muscle development myosin molecules form symmetrical thick filaments, which integrate with the thin filaments to produce the regular sarcomeric lattice. In Drosophila indirect flight muscles (IFMs) the details of this process can be studied using genetic approaches. The weeP26 transgenic line has a GFP-encoding exon inserted into the single Drosophila muscle myosin heavy chain gene, Mhc. The weeP26 IFM sarcomeres have a unique MHC-GFP-labelling pattern restricted to the sarcomere core, explained by non-translation of the GFP exon following alternative splicing. Characterisation of wild-type IFM MHC mRNA confirmed the presence of an alternately spliced isoform, expressed earlier than the major IFM-specific isoform. The two wild-type IFM-specific MHC isoforms differ by the presence of a C-terminal 'tailpiece' in the minor isoform. The sequential expression and assembly of these two MHCs into developing thick filaments suggest a role for the tailpiece in initiating A-band formation. The restriction of the MHC-GFP sarcomeric pattern in weeP26 is lifted when the IFM lack the IFM-specific myosin binding protein flightin, suggesting that it limits myosin dissociation from thick filaments. Studies of flightin binding to developing thick filaments reveal a progressive binding at the growing thick filament tips and in a retrograde direction to earlier assembled, proximal filament regions. We propose that this flightin binding restricts myosin molecule incorporation/dissociation during thick filament assembly and explains the location of the early MHC isoform pattern in the IFM A-band.

Electron Tomography of Cryofixed, Isometrically Contracting Insect Flight Muscle Reveals Novel Actin-Myosin Interactions

International Nuclear Information System (INIS)

Wu, Shenping; Liu, Jun; Reedy, Mary C.; Tregear, Richard T.; Winkler, Hanspeter; Franzini-Armstrong, Clara; Sasaki, Hiroyuki; Lucaveche, Carmen; Goldman, Yale E.; Reedy, Michael K.; Taylor, Kenneth A.

2010-01-01

Isometric muscle contraction, where force is generated without muscle shortening, is a molecular traffic jam in which the number of actin-attached motors is maximized and all states of motor action are trapped with consequently high heterogeneity. This heterogeneity is a major limitation to deciphering myosin conformational changes in situ. We used multivariate data analysis to group repeat segments in electron tomograms of isometrically contracting insect flight muscle, mechanically monitored, rapidly frozen, freeze substituted, and thin sectioned. Improved resolution reveals the helical arrangement of F-actin subunits in the thin filament enabling an atomic model to be built into the thin filament density independent of the myosin. Actin-myosin attachments can now be assigned as weak or strong by their motor domain orientation relative to actin. Myosin attachments were quantified everywhere along the thin filament including troponin. Strong binding myosin attachments are found on only four F-actin subunits, the 'target zone', situated exactly midway between successive troponin complexes. They show an axial lever arm range of 77 o /12.9 nm. The lever arm azimuthal range of strong binding attachments has a highly skewed, 127 o range compared with X-ray crystallographic structures. Two types of weak actin attachments are described. One type, found exclusively in the target zone, appears to represent pre-working-stroke intermediates. The other, which contacts tropomyosin rather than actin, is positioned M-ward of the target zone, i.e. the position toward which thin filaments slide during shortening. We present a model for the weak to strong transition in the myosin ATPase cycle that incorporates azimuthal movements of the motor domain on actin. Stress/strain in the S2 domain may explain azimuthal lever arm changes in the strong binding attachments. The results support previous conclusions that the weak attachments preceding force generation are very different from

Electron tomography of cryofixed, isometrically contracting insect flight muscle reveals novel actin-myosin interactions.

Directory of Open Access Journals (Sweden)

Shenping Wu

2010-09-01

Full Text Available Isometric muscle contraction, where force is generated without muscle shortening, is a molecular traffic jam in which the number of actin-attached motors is maximized and all states of motor action are trapped with consequently high heterogeneity. This heterogeneity is a major limitation to deciphering myosin conformational changes in situ.We used multivariate data analysis to group repeat segments in electron tomograms of isometrically contracting insect flight muscle, mechanically monitored, rapidly frozen, freeze substituted, and thin sectioned. Improved resolution reveals the helical arrangement of F-actin subunits in the thin filament enabling an atomic model to be built into the thin filament density independent of the myosin. Actin-myosin attachments can now be assigned as weak or strong by their motor domain orientation relative to actin. Myosin attachments were quantified everywhere along the thin filament including troponin. Strong binding myosin attachments are found on only four F-actin subunits, the "target zone", situated exactly midway between successive troponin complexes. They show an axial lever arm range of 77°/12.9 nm. The lever arm azimuthal range of strong binding attachments has a highly skewed, 127° range compared with X-ray crystallographic structures. Two types of weak actin attachments are described. One type, found exclusively in the target zone, appears to represent pre-working-stroke intermediates. The other, which contacts tropomyosin rather than actin, is positioned M-ward of the target zone, i.e. the position toward which thin filaments slide during shortening.We present a model for the weak to strong transition in the myosin ATPase cycle that incorporates azimuthal movements of the motor domain on actin. Stress/strain in the S2 domain may explain azimuthal lever arm changes in the strong binding attachments. The results support previous conclusions that the weak attachments preceding force generation are very

Formation of contractile networks and fibers in the medial cell cortex through myosin-II turnover, contraction, and stress-stabilization.

Science.gov (United States)

Nie, Wei; Wei, Ming-Tzo; Ou-Yang, H Daniel; Jedlicka, Sabrina S; Vavylonis, Dimitrios

2015-01-01

The morphology of adhered cells depends crucially on the formation of a contractile meshwork of parallel and cross-linked fibers along the contacting surface. The motor activity and minifilament assembly of non-muscle myosin-II is an important component of cortical cytoskeletal remodeling during mechanosensing. We used experiments and computational modeling to study cortical myosin-II dynamics in adhered cells. Confocal microscopy was used to image the medial cell cortex of HeLa cells stably expressing myosin regulatory light chain tagged with GFP (MRLC-GFP). The distribution of MRLC-GFP fibers and focal adhesions was classified into three types of network morphologies. Time-lapse movies show: myosin foci appearance and disappearance; aligning and contraction; stabilization upon alignment. Addition of blebbistatin, which perturbs myosin motor activity, leads to a reorganization of the cortical networks and to a reduction of contractile motions. We quantified the kinetics of contraction, disassembly and reassembly of myosin networks using spatio-temporal image correlation spectroscopy (STICS). Coarse-grained numerical simulations include bipolar minifilaments that contract and align through specified interactions as basic elements. After assuming that minifilament turnover decreases with increasing contractile stress, the simulations reproduce stress-dependent fiber formation in between focal adhesions above a threshold myosin concentration. The STICS correlation function in simulations matches the function measured in experiments. This study provides a framework to help interpret how different cortical myosin remodeling kinetics may contribute to different cell shape and rigidity depending on substrate stiffness. © 2015 Wiley Periodicals, Inc.

Direct observation of the myosin Va recovery stroke that contributes to unidirectional stepping along actin.

Directory of Open Access Journals (Sweden)

Katsuyuki Shiroguchi

2011-04-01

Full Text Available Myosins are ATP-driven linear molecular motors that work as cellular force generators, transporters, and force sensors. These functions are driven by large-scale nucleotide-dependent conformational changes, termed "strokes"; the "power stroke" is the force-generating swinging of the myosin light chain-binding "neck" domain relative to the motor domain "head" while bound to actin; the "recovery stroke" is the necessary initial motion that primes, or "cocks," myosin while detached from actin. Myosin Va is a processive dimer that steps unidirectionally along actin following a "hand over hand" mechanism in which the trailing head detaches and steps forward ∼72 nm. Despite large rotational Brownian motion of the detached head about a free joint adjoining the two necks, unidirectional stepping is achieved, in part by the power stroke of the attached head that moves the joint forward. However, the power stroke alone cannot fully account for preferential forward site binding since the orientation and angle stability of the detached head, which is determined by the properties of the recovery stroke, dictate actin binding site accessibility. Here, we directly observe the recovery stroke dynamics and fluctuations of myosin Va using a novel, transient caged ATP-controlling system that maintains constant ATP levels through stepwise UV-pulse sequences of varying intensity. We immobilized the neck of monomeric myosin Va on a surface and observed real time motions of bead(s attached site-specifically to the head. ATP induces a transient swing of the neck to the post-recovery stroke conformation, where it remains for ∼40 s, until ATP hydrolysis products are released. Angle distributions indicate that the post-recovery stroke conformation is stabilized by ≥ 5 k(BT of energy. The high kinetic and energetic stability of the post-recovery stroke conformation favors preferential binding of the detached head to a forward site 72 nm away. Thus, the recovery

Stress generation by myosin minifilaments in actin bundles

International Nuclear Information System (INIS)

Dasanayake, Nilushi L; Carlsson, Anders E

2013-01-01

Forces and stresses generated by the action of myosin minifilaments are analyzed in idealized computer-generated actin bundles, and compared to results for isotropic actin networks. The bundles are generated as random collections of actin filaments in two dimensions with constrained orientations, crosslinked and attached to two fixed walls. Myosin minifilaments are placed on actin filament pairs and allowed to move and deform the network so that it exerts forces on the walls. The vast majority of simulation runs end with contractile minifilament stress, because minifilaments rotate into energetically stable contractile configurations. This process is aided by the bending and stretching of actin filaments, which accomodate minifilament rotation. Stresses for bundles are greater than those for isotropic networks, and antiparallel filaments generate more tension than parallel filaments. The forces transmitted by the actin network to the walls of the simulation cell often exceed the tension in the minifilament itself. (paper)

Phosphorylation of Tropomyosin Extends Cooperative Binding of Myosin Beyond a Single Regulatory Unit

OpenAIRE

Rao, Vijay S.; Marongelli, Ellisha N.; Guilford, William H.

2009-01-01

Tropomyosin (Tm) is one of the major phosphoproteins comprising the thin filament of muscle. However, the specific role of Tm phosphorylation in modulating the mechanics of actomyosin interaction has not been determined. Here we show that Tm phosphorylation is necessary for long-range cooperative activation of myosin binding. We used a novel optical trapping assay to measure the isometric stall force of an ensemble of myosin molecules moving actin filaments reconstituted with either natively ...

BMP-2 Overexpression Augments Vascular Smooth Muscle Cell Motility by Upregulating Myosin Va via Erk Signaling

Directory of Open Access Journals (Sweden)

Ming Zhang

2014-01-01

Full Text Available Background. The disruption of physiologic vascular smooth muscle cell (VSMC migration initiates atherosclerosis development. The biochemical mechanisms leading to dysfunctional VSMC motility remain unknown. Recently, cytokine BMP-2 has been implicated in various vascular physiologic and pathologic processes. However, whether BMP-2 has any effect upon VSMC motility, or by what manner, has never been investigated. Methods. VSMCs were adenovirally transfected to genetically overexpress BMP-2. VSMC motility was detected by modified Boyden chamber assay, confocal time-lapse video assay, and a colony wounding assay. Gene chip array and RT-PCR were employed to identify genes potentially regulated by BMP-2. Western blot and real-time PCR detected the expression of myosin Va and the phosphorylation of extracellular signal-regulated kinases 1/2 (Erk1/2. Immunofluorescence analysis revealed myosin Va expression locale. Intracellular Ca2+ oscillations were recorded. Results. VSMC migration was augmented in VSMCs overexpressing BMP-2 in a dose-dependent manner. siRNA-mediated knockdown of myosin Va inhibited VSMC motility. Both myosin Va mRNA and protein expression significantly increased after BMP-2 administration and were inhibited by Erk1/2 inhibitor U0126. BMP-2 induced Ca2+ oscillations, generated largely by a “cytosolic oscillator”. Conclusion. BMP-2 significantly increased VSMCs migration and myosin Va expression, via the Erk signaling pathway and intracellular Ca2+ oscillations. We provide additional insight into the pathophysiology of atherosclerosis, and inhibition of BMP-2-induced myosin Va expression may represent a potential therapeutic strategy.

Levels of myosin heavy chain mRNA transcripts and content of protein isoforms in the slow soleus muscle of 7 month-old rats with altered thyroid status

Czech Academy of Sciences Publication Activity Database

Vadászová, Adriana; Hudecová, S.; Križanová, O.; Soukup, Tomáš

2006-01-01

Roč. 55, č. 2 (2006), s. 221-225 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GD305/03/H148; GA ČR(CZ) GA304/05/0327 Grant - others:VEGA(SK) 2/6078; SAV(SK) APVT-51-027404; NATO(XE) 979876; MYORES(XE) 511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : myosin heavy chain * thyroid hormones status * mRNA transcripts Subject RIV: ED - Physiology Impact factor: 2.093, year: 2006

Myosin light chain phosphorylation is critical for adaptation to cardiac stress.

Science.gov (United States)

Warren, Sonisha A; Briggs, Laura E; Zeng, Huadong; Chuang, Joyce; Chang, Eileen I; Terada, Ryota; Li, Moyi; Swanson, Maurice S; Lecker, Stewart H; Willis, Monte S; Spinale, Francis G; Maupin-Furlowe, Julie; McMullen, Julie R; Moss, Richard L; Kasahara, Hideko

2012-11-27

Cardiac hypertrophy is a common response to circulatory or neurohumoral stressors as a mechanism to augment contractility. When the heart is under sustained stress, the hypertrophic response can evolve into decompensated heart failure, although the mechanism(s) underlying this transition remain largely unknown. Because phosphorylation of cardiac myosin light chain 2 (MLC2v), bound to myosin at the head-rod junction, facilitates actin-myosin interactions and enhances contractility, we hypothesized that phosphorylation of MLC2v plays a role in the adaptation of the heart to stress. We previously identified an enzyme that predominantly phosphorylates MLC2v in cardiomyocytes, cardiac myosin light-chain kinase (cMLCK), yet the role(s) played by cMLCK in regulating cardiac function in health and disease remain to be determined. We found that pressure overload induced by transaortic constriction in wild-type mice reduced phosphorylated MLC2v levels by ≈40% and cMLCK levels by ≈85%. To examine how a reduction in cMLCK and the corresponding reduction in phosphorylated MLC2v affect function, we generated Mylk3 gene-targeted mice and transgenic mice overexpressing cMLCK specifically in cardiomyocytes. Pressure overload led to severe heart failure in cMLCK knockout mice but not in mice with cMLCK overexpression in which cMLCK protein synthesis exceeded degradation. The reduction in cMLCK protein during pressure overload was attenuated by inhibition of ubiquitin-proteasome protein degradation systems. Our results suggest the novel idea that accelerated cMLCK protein turnover by the ubiquitin-proteasome system underlies the transition from compensated hypertrophy to decompensated heart failure as a result of reduced phosphorylation of MLC2v.

Interaction of thyroid state and denervation on skeletal myosin heavy chain expression

Science.gov (United States)

Haddad, F.; Arnold, C.; Zeng, M.; Baldwin, K.

1997-01-01

The goal of this study was to examine the effects of altered thyroid state and denervation (Den) on skeletal myosin heavy chain (MHC) expression in the plantaris and soleus muscles. Rats were subjected to unilateral denervation (Den) and randomly assigned to one of three groups: (1) euthyroid; (2) hyperthyroid; (3) and hypothyroid. Denervation caused severe muscle atrophy and muscle-type specific MHC transformation. Denervation transformed the soleus to a faster muscle, and its effects required the presence of circulating thyroid hormone. In contrast, denervation transformed the plantaris to a slower muscle independently of thyroid state. Furthermore, thyroid hormone effects did not depend upon innervation status in the soleus, while they required the presence of the nerve in the plantaris. Collectively, these findings suggest that both thyroid hormone and intact nerve (a) differentially affect MHC transformations in fast and slow muscle; and (b) are important factors in regulating the optimal expression of both type I and IIB MHC genes. This research suggests that for patients with nerve damage and/or paralysis, both muscle mass and biochemical properties can also be affected by the thyroid state.

Myosin XI-dependent formation of tubular structures from endoplasmic reticulum isolated from tobacco cultured BY-2 cells.

Science.gov (United States)

Yokota, Etsuo; Ueda, Haruko; Hashimoto, Kohsuke; Orii, Hidefumi; Shimada, Tomoo; Hara-Nishimura, Ikuko; Shimmen, Teruo

2011-05-01

The reticular network of the endoplasmic reticulum (ER) consists of tubular and lamellar elements and is arranged in the cortical region of plant cells. This network constantly shows shape change and remodeling motion. Tubular ER structures were formed when GTP was added to the ER vesicles isolated from tobacco (Nicotiana tabacum) cultured BY-2 cells expressing ER-localized green fluorescent protein. The hydrolysis of GTP during ER tubule formation was higher than that under conditions in which ER tubule formation was not induced. Furthermore, a shearing force, such as the flow of liquid, was needed for the elongation/extension of the ER tubule. The shearing force was assumed to correspond to the force generated by the actomyosin system in vivo. To confirm this hypothesis, the S12 fraction was prepared, which contained both cytosol and microsome fractions, including two classes of myosins, XI (175-kD myosin) and VIII (BY-2 myosin VIII-1), and ER-localized green fluorescent protein vesicles. The ER tubules and their mesh-like structures were arranged in the S12 fraction efficiently by the addition of ATP, GTP, and exogenous filamentous actin. The tubule formation was significantly inhibited by the depletion of 175-kD myosin from the S12 fraction but not BY-2 myosin VIII-1. Furthermore, a recombinant carboxyl-terminal tail region of 175-kD myosin also suppressed ER tubule formation. The tips of tubules moved along filamentous actin during tubule elongation. These results indicated that the motive force generated by the actomyosin system contributes to the formation of ER tubules, suggesting that myosin XI is responsible not only for the transport of ER in cytoplasm but also for the reticular organization of cortical ER.

Myosin IIA participates in docking of Glut4 storage vesicles with the plasma membrane in 3T3-L1 adipocytes

International Nuclear Information System (INIS)

Chung, Le Thi Kim; Hosaka, Toshio; Harada, Nagakatsu; Jambaldorj, Bayasgalan; Fukunaga, Keiko; Nishiwaki, Yuka; Teshigawara, Kiyoshi; Sakai, Tohru; Nakaya, Yutaka; Funaki, Makoto

2010-01-01

In adipocytes and myocytes, insulin stimulation translocates glucose transporter 4 (Glut4) storage vesicles (GSVs) from their intracellular storage sites to the plasma membrane (PM) where they dock with the PM. Then, Glut4 is inserted into the PM and initiates glucose uptake into these cells. Previous studies using chemical inhibitors demonstrated that myosin II participates in fusion of GSVs and the PM and increase in the intrinsic activity of Glut4. In this study, the effect of myosin IIA on GSV trafficking was examined by knocking down myosin IIA expression. Myosin IIA knockdown decreased both glucose uptake and exposures of myc-tagged Glut4 to the cell surface in insulin-stimulated cells, but did not affect insulin signal transduction. Interestingly, myosin IIA knockdown failed to decrease insulin-dependent trafficking of Glut4 to the PM. Moreover, in myosin IIA knockdown cells, insulin-stimulated binding of GSV SNARE protein, vesicle-associated membrane protein 2 (VAMP2) to PM SNARE protein, syntaxin 4 was inhibited. These data suggest that myosin IIA plays a role in insulin-stimulated docking of GSVs to the PM in 3T3-L1 adipocytes through SNARE complex formation.

The local expression of adult chicken heart myosins during development. I. The three days embryonic chicken heart

NARCIS (Netherlands)

Sanders, E.; Moorman, A. F.; Los, J. A.

1984-01-01

Immunofluorescence studies were performed on serial sections of three days embryonic chicken hearts using antibodies specific for adult atrial and ventricular myosin heavy chains respectively. The anti-ventricular myosin serum reacted with the entire myocardium showing a decreasing intensity going

CALIX[4]ARENE C-99 INHIBITS MYOSIN ATPase ACTIVITY AND CHANGES THE ORGANIZATION OF CONTRACTILE FILAMENTS OF MYOMETRIUM.

Science.gov (United States)

Labyntseva, R D; Bevza, A A; Lul'ko, A O; Cherenok, S O; Kalchenko, V I; Kosterin, S O

2015-01-01

Calix[4]arenes are cup-like macrocyclic (polyphenolic) compounds, they are regarded as promising molecular "platforms" for the design of new physiologically active compounds. We have earlier found that calix[4]arene C-99 inhibits the ATPase activity of actomyosin and myosin subfragment-1 of pig uterus in vitro. The aim of this study was to investigate the interaction of calix[4]arene C-99 with myosin from rat uterine myocytes. It was found that the ATPase activity of myosin prepared from pre-incubated with 100 mM of calix[4]arene C-99 myocytes was almost 50% lower than in control. Additionally, we have revealed the effect of calix[4]arene C-99 on the subcellular distribution of actin and myosin in uterus myocytes by the method of confocal microscopy. This effect can be caused by reorganization of the structure of the contractile smooth muscle cell proteins due to their interaction with calix[4]arene. The obtained results demonstrate the ability of calix[4]arene C-99 to penetrate into the uterus muscle cells and affect not only the myosin ATPase activity, but also the structure of the actin and myosin filaments in the myometrial cells. Demonstrated ability of calix[4]arene C-99 can be used for development of new pharmacological agents for efficient normalization of myometrial contractile hyperfunction.

Calix[4]arene C-99 inhibits myosin ATPase activity and changes the organization of contractile filaments of myometrium

Directory of Open Access Journals (Sweden)

R. D. Labyntseva,

2015-12-01

Full Text Available Calix[4]arenes are cup-like macrocyclic (polyphenolic compounds, they are regarded as promising molecular “platforms” for the design of new physiologically active compounds. We have earlier found that сalix[4]arenе C-99 inhibits the ATPase activity of actomyosin and myosin subfragment-1 of pig uterus іn vitro. The aim of this study was to investigate the interaction of calix[4]arene C-99 with myosin from rat uterine myocytes. It was found that the ATPase activity of myosin prepared from pre-incubated with 100 mM of calix[4]arene C-99 myocytes was almost 50% lower than in control. Additionally, we have revealed the effect of calix[4]arene C-99 on the subcellular distribution of actin and myosin in uterus myocytes by the method of confocal microscopy. This effect can be caused by reorganization of the structure of the contractile smooth muscle cell proteins due to their interaction with calix[4]arene. The obtained results demonstrate the ability of calix[4]arene C-99 to penetrate into the uterus muscle cells and affect not only the myosin ATPase activity, but also the structure of the actin and myosin filaments in the myometrial cells. Demonstrated ability of calix[4]arene C-99 can be used for development of new pharmacological agents for efficient normalization of myometrial contractile hyperfunction.

Clinical study on the time courses of serum myosin light chain I levels in patients with acute myocardial infarction

International Nuclear Information System (INIS)

Nakanishi, Masako; Saiki, Yasuhiko; Ui, Kazuyo

1992-01-01

Changes of serum myosin light chain I (Myosin LCI) concentrations and creatine kinase (CK) activities were serially measured in 23 patients with acute myocardial infarction. Intracoronary thrombolysis was performed in 14 patients (ICT group) while the remaining 9 patients were treated in the conventional manner (non ICT group). The relationships between the maximum levels of serum Myosin LCI or CK and a myocardial infarct size index or left ventricular function were evaluated in 18 patients. The myocardial infarct size index was determined by 201 Tl myocardial scintigrams performed in the chronic phase. Multiple peaks of Myosin LCI were observed in 64% (9/14) of the ICT group and the first peak in 6 of these patients appeared much earlier in the same time as CK peak than in the non-ICT group, while multiple peaks were seen only in one case in the non-ICT group. The infarct size index by 201 Tl myocardial SPECT correlated with maximum Myosin LCI levels (r=0.88, p<0.001, n=10) and CK activities (r=0.67, p<0.05, n=10). These results indicate that the measurement of serum Myosin LCI is very useful for estimating the extent of myocardial damage and suggest that myocardial degeneration occurs at a very early phase of myocardial infarction. (author)

21 CFR 1250.96 - Rodent control.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rodent control. 1250.96 Section 1250.96 Food and... SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be... of rodent control. ...

Drosophila UNC-45 prevents heat-induced aggregation of skeletal muscle myosin and facilitates refolding of citrate synthase

Energy Technology Data Exchange (ETDEWEB)

Melkani, Girish C.; Lee, Chi F.; Cammarato, Anthony [Department of Biology and the Molecular Biology Institute, San Diego State University, San Diego, CA 92182-4614 (United States); Bernstein, Sanford I., E-mail: sbernst@sciences.sdsu.edu [Department of Biology and the Molecular Biology Institute, San Diego State University, San Diego, CA 92182-4614 (United States)

2010-05-28

UNC-45 belongs to the UCS (UNC-45, CRO1, She4p) domain protein family, whose members interact with various classes of myosin. Here we provide structural and biochemical evidence that Escherichia coli-expressed Drosophila UNC-45 (DUNC-45) maintains the integrity of several substrates during heat-induced stress in vitro. DUNC-45 displays chaperone function in suppressing aggregation of the muscle myosin heavy meromyosin fragment, the myosin S-1 motor domain, {alpha}-lactalbumin and citrate synthase. Biochemical evidence is supported by electron microscopy, which reveals the first structural evidence that DUNC-45 prevents inter- or intra-molecular aggregates of skeletal muscle heavy meromyosin caused by elevated temperatures. We also demonstrate for the first time that UNC-45 is able to refold a denatured substrate, urea-unfolded citrate synthase. Overall, this in vitro study provides insight into the fate of muscle myosin under stress conditions and suggests that UNC-45 protects and maintains the contractile machinery during in vivo stress.

Blebbistatin, a myosin II inhibitor, suppresses Ca(2+)-induced and "sensitized"-contraction of skinned tracheal muscles from guinea pig.

Science.gov (United States)

Yumoto, Masatoshi; Watanabe, Masaru

2013-01-01

Blebbistatin, a potent inhibitor of myosin II, has inhibiting effects on Ca(2+)-induced contraction and contractile filament organization without affecting the Ca(2+)-sensitivity to the force and phosphorylation level of myosin regulatory light chain (MLC20) in skinned (cell membrane permeabilized) taenia cecum from the guinea pig (Watanabe et al., Am J Physiol Cell Physiol. 2010; 298: C1118-26). In the present study, we investigated blebbistatin effects on the contractile force of skinned tracheal muscle, in which myosin filaments organization is more labile than that in the taenia cecum. Blebbistatin at 10 μM or higher suppressed Ca(2+)-induced tension development at any given Ca(2+) concentration, but had little effects on the Ca(2+)- induced myosin light chain phosphorylation. Also blebbistatin at 10 μM and higher significantly suppressed GTP-γS-induced "sensitized" force development. Since the force inhibiting effects of blebbistatin on the skinned trachea were much stronger than those in skinned taenia cecum, blebbistatin might directly affect myosin filaments organization.

The Rho kinases I and II regulate different aspects of myosin II activity

DEFF Research Database (Denmark)

Yoneda, Atsuko; Multhaupt, Hinke A B; Couchman, John R

2005-01-01

The homologous mammalian rho kinases (ROCK I and II) are assumed to be functionally redundant, based largely on kinase construct overexpression. As downstream effectors of Rho GTPases, their major substrates are myosin light chain and myosin phosphatase. Both kinases are implicated in microfilament...... bundle assembly and smooth muscle contractility. Here, analysis of fibroblast adhesion to fibronectin revealed that although ROCK II was more abundant, its activity was always lower than ROCK I. Specific reduction of ROCK I by siRNA resulted in loss of stress fibers and focal adhesions, despite...

Effects of BTS (N-benzyl-p-toluene sulphonamide), an inhibitor for myosin-actin interaction, on myofibrillogenesis in skeletal muscle cells in culture.

Science.gov (United States)

Kagawa, Maiko; Sato, Naruki; Obinata, Takashi

2006-11-01

Actin filaments align around myosin filaments in the correct polarity and in a hexagonal arrangement to form cross-striated structures. It has been postulated that this myosin-actin interaction is important in the initial phase of myofibrillogenesis. It was previously demonstrated that an inhibitor of actin-myosin interaction, BDM (2,3-butanedione monoxime), suppresses myofibril formation in muscle cells in culture. However, further study showed that BDM also exerts several additional effects on living cells. In this study, we further examined the role of actin-myosin interaction in myofibril assembly in primary cultures of chick embryonic skeletal muscle by applying a more specific inhibitor, BTS (N-benzyl-p-toluene sulphonamide), of myosin ATPase and actin-myosin interaction. The assembly of sarcomeric structures from myofibrillar proteins was examined by immunocytochemical methods with the application of BTS to myotubes just after fusion. Addition of BTS (10-50 microM) significantly suppressed the organization of actin and myosin into cross-striated structures. BTS also interfered in the organization of alpha-actinin, C-protein (or MyBP-C), and connectin (or titin) into ordered striated structures, though the sensitivity was less. Moreover, when myotubes cultured in the presence of BTS were transferred to a control medium, sarcomeric structures were formed in 2-3 days, indicating that the inhibitory effect of BTS on myotubes is reversible. These results show that actin-myosin interaction plays a critical role in the process of myofibrillogenesis.

Effects of chronic Akt/mTOR inhibition by rapamycin on mechanical overload-induced hypertrophy and myosin heavy chain transition in masseter muscle.

Science.gov (United States)

Umeki, Daisuke; Ohnuki, Yoshiki; Mototani, Yasumasa; Shiozawa, Kouichi; Fujita, Takayuki; Nakamura, Yoshiki; Saeki, Yasutake; Okumura, Satoshi

2013-01-01

To examine the effects of the Akt/mammalian target of rapamycin (mTOR) pathway on masseter muscle hypertrophy and myosin heavy chain (MHC) transition in response to mechanical overload, we analyzed the effects of bite-opening (BO) on the hypertrophy and MHC composition of masseter muscle of BO-rats treated or not treated with rapamycin (RAPA), a selective mTOR inhibitor. The masseter muscle weight in BO-rats was significantly greater than that in controls, and this increase was attenuated by RAPA treatment. Expression of slow-twitch MHC isoforms was significantly increased in BO-rats with/without RAPA treatment, compared with controls, but the magnitude of the increase was much smaller in RAPA-treated BO-rats. Phosphorylation of p44/42 MAPK (ERK1/2), which preserves fast-twitch MHC isoforms in skeletal muscle, was significantly decreased in BO-rats, but the decrease was abrogated by RAPA treatment. Calcineurin signaling is known to be important for masseter muscle hypertrophy and fast-to-slow MHC isoform transition, but expression of known calcineurin activity modulators was unaffected by RAPA treatment. Taken together, these results indicate that the Akt/mTOR pathway is involved in both development of masseter muscle hypertrophy and fast-to-slow MHC isoform transition in response to mechanical overload with inhibition of the ERK1/2 pathway and operates independently of the calcineurin pathway.

Discoidin Domain Receptor 1 Mediates Myosin-Dependent Collagen Contraction

Directory of Open Access Journals (Sweden)

Nuno M. Coelho

2017-02-01

Full Text Available Discoidin domain receptor 1 (DDR1 is a tyrosine kinase collagen adhesion receptor that mediates cell migration through association with non-muscle myosin IIA (NMIIA. Because DDR1 is implicated in cancer fibrosis, we hypothesized that DDR1 interacts with NMIIA to enable collagen compaction by traction forces. Mechanical splinting of rat dermal wounds increased DDR1 expression and collagen alignment. In periodontal ligament of DDR1 knockout mice, collagen mechanical reorganization was reduced >30%. Similarly, cultured cells with DDR1 knockdown or expressing kinase-deficient DDR1d showed 50% reduction of aligned collagen. Tractional remodeling of collagen was dependent on DDR1 clustering, activation, and interaction of the DDR1 C-terminal kinase domain with NMIIA filaments. Collagen remodeling by traction forces, DDR1 tyrosine phosphorylation, and myosin light chain phosphorylation were increased on stiff versus soft substrates. Thus, DDR1 clustering, activation, and interaction with NMIIA filaments enhance the collagen tractional remodeling that is important for collagen compaction in fibrosis.

Virtual reality systems for rodents.

Science.gov (United States)

Thurley, Kay; Ayaz, Aslı

2017-02-01

Over the last decade virtual reality (VR) setups for rodents have been developed and utilized to investigate the neural foundations of behavior. Such VR systems became very popular since they allow the use of state-of-the-art techniques to measure neural activity in behaving rodents that cannot be easily used with classical behavior setups. Here, we provide an overview of rodent VR technologies and review recent results from related research. We discuss commonalities and differences as well as merits and issues of different approaches. A special focus is given to experimental (behavioral) paradigms in use. Finally we comment on possible use cases that may further exploit the potential of VR in rodent research and hence inspire future studies.

Probing muscle myosin motor action: x-ray (m3 and m6) interference measurements report motor domain not lever arm movement.

Science.gov (United States)

Knupp, Carlo; Offer, Gerald; Ranatunga, K W; Squire, John M

2009-07-10

The key question in understanding how force and movement are produced in muscle concerns the nature of the cyclic interaction of myosin molecules with actin filaments. The lever arm of the globular head of each myosin molecule is thought in some way to swing axially on the actin-attached motor domain, thus propelling the actin filament past the myosin filament. Recent X-ray diffraction studies of vertebrate muscle, especially those involving the analysis of interference effects between myosin head arrays in the two halves of the thick filaments, have been claimed to prove that the lever arm moves at the same time as the sliding of actin and myosin filaments in response to muscle length or force steps. It was suggested that the sliding of myosin and actin filaments, the level of force produced and the lever arm angle are all directly coupled and that other models of lever arm movement will not fit the X-ray data. Here, we show that, in addition to interference across the A-band, which must be occurring, the observed meridional M3 and M6 X-ray intensity changes can all be explained very well by the changing diffraction effects during filament sliding caused by heads stereospecifically attached to actin moving axially relative to a population of detached or non-stereospecifically attached heads that remain fixed in position relative to the myosin filament backbone. Crucially, and contrary to previous interpretations, the X-ray interference results provide little direct information about the position of the myosin head lever arm; they are, in fact, reporting relative motor domain movements. The implications of the new interpretation are briefly assessed.

Myosin Va Plays a Role in Nitrergic Smooth Muscle Relaxation in Gastric Fundus and Corpora Cavernosa of Penis

Science.gov (United States)

Carew, Josephine A.; Goyal, Raj K.; Sullivan, Maryrose P.

2014-01-01

The intracellular motor protein myosin Va is involved in nitrergic neurotransmission possibly by trafficking of neuronal nitric oxide synthase (nNOS) within the nerve terminals. In this study, we examined the role of myosin Va in the stomach and penis, proto-typical smooth muscle organs in which nitric oxide (NO) mediated relaxation is critical for function. We used confocal microscopy and co-immunoprecipitation of tissue from the gastric fundus (GF) and penile corpus cavernosum (CCP) to localize myosin Va with nNOS and demonstrate their molecular interaction. We utilized in vitro mechanical studies to test whether smooth muscle relaxations during nitrergic neuromuscular neurotransmission is altered in DBA (dilute, brown, non-agouti) mice which lack functional myosin Va. Myosin Va was localized in nNOS-positive nerve terminals and was co-immunoprecipitated with nNOS in both GF and CCP. In comparison to C57BL/6J wild type (WT) mice, electrical field stimulation (EFS) of precontracted smooth muscles of GF and CCP from DBA animals showed significant impairment of nitrergic relaxation. An NO donor, Sodium nitroprusside (SNP), caused comparable levels of relaxation in smooth muscles of WT and DBA mice. These normal postjunctional responses to SNP in DBA tissues suggest that impairment of smooth muscle relaxation resulted from inhibition of NO synthesis in prejunctional nerve terminals. Our results suggest that normal physiological processes of relaxation of gastric and cavernosal smooth muscles that facilitate food accommodation and penile erection, respectively, may be disrupted under conditions of myosin Va deficiency, resulting in complications like gastroparesis and erectile dysfunction. PMID:24516539

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury.

Science.gov (United States)

Smith, H K; Plyley, M J; Rodgers, C D; McKee, N H

1999-07-01

The extent and stability of the expression of developmental isoforms of myosin heavy chain (MHCd), and their association with cellular morphology, were determined in adult rat skeletal muscle fibres following injury induced by eccentrically-biased exercise. Adult female Wistar rats [274 (10) g] were either assigned as non-exercised controls or subjected to 30 min of treadmill exercise (grade, -16 degrees; speed, 15 m x min(-1)), and then sacrificed following 1, 2, 4, 7, or 12 days of recovery (n = 5-6 per group). Histologically and immunohistologically stained serial, transverse cryosections of the soleus (S), vastus intermedius (VI), and tibialis anterior (TA) muscles were examined using light microscopy and digital imaging. Fibres staining positively for MHCd (MHCd+) were seldom detected in the TA. In the VI and S, higher proportions of MHCd+ fibres (0.8% and 2.5%, respectively) were observed in rats at 4 and 7 days post-exercise, in comparison to all other groups combined (0.2%, 1.2%; P < or = 0.01). In S, MHCd+ fibres were observed less frequently by 12 days (0.7%) than at 7 days (2.6%) following exercise. The majority (85.1%) of the MHCd+ fibres had morphological characteristics indicative of either damage, degeneration, repair or regeneration. Most of the MHCd+ fibres also expressed adult slow, and/or fast myosin heavy chain. Quantitatively, the MHCd+ fibres were smaller (< 2500 microm2) and more angular than fibres not expressing MHCd. Thus, there was a transient increase in a small, but distinct population of MHCd+ fibres following unaccustomed, functional exercise in adult rat S and VI muscles. The observed close coupling of MHCd expression with morphological changes within muscle fibres suggests that these characteristics have a common, initial exercise-induced injury-related stimulus.

Carboxyl-terminal-dependent recruitment of nonmuscle myosin II to megakaryocyte contractile ring during polyploidization.

Science.gov (United States)

Badirou, Idinath; Pan, Jiajia; Legrand, Céline; Wang, Aibing; Lordier, Larissa; Boukour, Siham; Roy, Anita; Vainchenker, William; Chang, Yunhua

2014-10-16

Endomitosis is a unique megakaryocyte (MK) differentiation process that is the consequence of a late cytokinesis failure associated with a contractile ring defect. Evidence from in vitro studies has revealed the distinct roles of 2 nonmuscle myosin IIs (NMIIs) on MK endomitosis: only NMII-B (MYH10), but not NMII-A (MYH9), is localized in the MK contractile ring and implicated in mitosis/endomitosis transition. Here, we studied 2 transgenic mouse models in which nonmuscle myosin heavy chain (NMHC) II-A was genetically replaced either by II-B or by a chimeric NMHCII that combined the head domain of II-A with the rod and tail domains of II-B. This study provides in vivo evidence on the specific role of NMII-B on MK polyploidization. It demonstrates that the carboxyl-terminal domain of the heavy chains determines myosin II localization to the MK contractile ring and is responsible for the specific role of NMII-B in MK polyploidization.

Increased expression of Myosin binding protein H in the skeletal muscle of amyotrophic lateral sclerosis patients

KAUST Repository

Conti, Antonio

2014-01-01

Amyotrophic lateral sclerosis (ALS) is a severe and fatal neurodegenerative disease of still unknown pathogenesis. Recent findings suggest that the skeletal muscle may play an active pathogenetic role. To investigate ALS\\'s pathogenesis and to seek diagnostic markers, we analyzed skeletal muscle biopsies with the differential expression proteomic approach. We studied skeletal muscle biopsies from healthy controls (CN), sporadic ALS (sALS), motor neuropathies (MN) and myopathies (M). Pre-eminently among several differentially expressed proteins, Myosin binding protein H (MyBP-H) expression in ALS samples was anomalously high. MyBP-H is a component of the thick filaments of the skeletal muscle and has strong affinity for myosin, but its function is still unclear. High MyBP-H expression level was associated with abnormal expression of Rho kinase 2 (ROCK2), LIM domain kinase 1 (LIMK1) and cofilin2, that might affect the actin-myosin interaction. We propose that MyBP-H expression level serves, as a putative biomarker in the skeletal muscle, to discriminate ALS from motor neuropathies, and that it signals the onset of dysregulation in actin-myosin interaction; this in turn might contribute to the pathogenesis of ALS. © 2013 Elsevier B.V.

Alterations in rat cardiac myosin isozymes induced by whole-body irradiation are prevented by 3,5,3'-L-triiodothyronine

International Nuclear Information System (INIS)

Litten, R.Z.; Fein, H.G.; Gainey, G.T.; Walden, T.L.; Smallridge, R.C.

1990-01-01

Changes in cardiac myosin isozymes and serum thyroid hormone levels were investigated in rats following 10 Gy whole-body gamma irradiation. The percent beta-myosin heavy chain increased from 21.3 ± 1.8 to 28.1 ± 6.8 (NS) at 3-day postirradiation, 37.7 ± 1.9 (P less than .001) at 6-day postirradiation, and 43.8 ± 3.3 (P less than .001) at 9-day postirradiation. Along with the change in myosin isozymes was a significant 53% decrease (P less than .001) in the serum thyroxine (T4) level by day 3 postirradiation, remaining depressed through day 9 postirradiation. The serum 3,5,3'-triiodothyronine (T3) level, however, was normal until day 9, when significant depression was also observed. In contrast, the thyroid-stimulating hormone (TSH) level was significantly increased by fourfold at day 3, returning to near normal values by day 9 postirradiation. Daily injections of physiological doses of T3 (0.3 microgram/100 g body weight) prevented the change in the myosin isozymes following whole-body irradiation. Daily pharmacological injections of T3 (3.0 micrograms/100 g body weight) to the irradiated rats produced a further decrease in the percent beta-myosin heavy chain (below control values) indicating tissue hyperthyroidism. Thus, this study suggests that the change in myosin isozymes following whole-body irradiation is caused by an alteration in thyroid hormone activity

Use it or lose it: tonic activity of slow motoneurons promotes their survival and preferentially increases slow fiber-type groupings in muscles of old lifelong recreational sportsmen

Directory of Open Access Journals (Sweden)

Simone Mosole

2016-11-01

Full Text Available Histochemistry, immuno-histochemistry, gel electrophoresis of single muscle fibers and electromyography of aging muscles and nerves suggest that: i denervation contributes to muscle atrophy, ii impaired mobility accelerates the process, and iii lifelong running protects against loss of motor units. Recent corroborating results on the muscle effects of Functional Electrical Stimulation (FES of aged muscles will be also mentioned, but we will in particular discuss how and why a lifelong increased physical activity sustains reinnervation of muscle fibers. By analyzing distribution and density of muscle fibers co-expressing fast and slow Myosin Heavy Chains (MHC we are able to distinguish the transforming muscle fibers due to activity related plasticity, to those that adapt muscle fiber properties to denervation and reinnervation. In muscle biopsies from septuagenarians with a history of lifelong high-level recreational activity we recently observed in comparison to sedentary seniors: 1. decreased proportion of small-size angular myofibers (denervated muscle fibers; 2. considerable increase of fiber-type groupings of the slow type (reinnervated muscle fibers; 3. sparse presence of muscle fibers co-expressing fast and slow MHC. Immuno-histochemical characteristics fluctuate from those with scarce fiber-type modulation and groupings to almost complete transformed muscles, going through a process in which isolated fibers co-expressing fast and slow MHC fill the gaps among fiber groupings. Data suggest that lifelong high-level exercise allows the body to adapt to the consequences of the age-related denervation and that it preserves muscle structure and function by saving otherwise lost muscle fibers through recruitment to different slow motor units. This is an opposite behavior of that described in long term denervated or resting muscles. These effects of lifelong high level activity seems to act primarily on motor neurons, in particular on those always

Use it or Lose It: Tonic Activity of Slow Motoneurons Promotes Their Survival and Preferentially Increases Slow Fiber-Type Groupings in Muscles of Old Lifelong Recreational Sportsmen

Science.gov (United States)

Mosole, Simone; Carraro, Ugo; Kern, Helmut; Loefler, Stefan; Zampieri, Sandra

2016-01-01

Histochemistry, immuno-histochemistry, gel electrophoresis of single muscle fibers and electromyography of aging muscles and nerves suggest that: i) denervation contributes to muscle atrophy, ii) impaired mobility accelerates the process, and iii) lifelong running protects against loss of motor units. Recent corroborating results on the muscle effects of Functional Electrical Stimulation (FES) of aged muscles will be also mentioned, but we will in particular discuss how and why a lifelong increased physical activity sustains reinnervation of muscle fibers. By analyzing distribution and density of muscle fibers co-expressing fast and slow Myosin Heavy Chains (MHC) we are able to distinguish the transforming muscle fibers due to activity related plasticity, to those that adapt muscle fiber properties to denervation and reinnervation. In muscle biopsies from septuagenarians with a history of lifelong high-level recreational activity we recently observed in comparison to sedentary seniors: 1. decreased proportion of small-size angular myofibers (denervated muscle fibers); 2. considerable increase of fiber-type groupings of the slow type (reinnervated muscle fibers); 3. sparse presence of muscle fibers co-expressing fast and slow MHC. Immuno-histochemical characteristics fluctuate from those with scarce fiber-type modulation and groupings to almost complete transformed muscles, going through a process in which isolated fibers co-expressing fast and slow MHC fill the gaps among fiber groupings. Data suggest that lifelong high-level exercise allows the body to adapt to the consequences of the age-related denervation and that it preserves muscle structure and function by saving otherwise lost muscle fibers through recruitment to different slow motor units. This is an opposite behavior of that described in long term denervated or resting muscles. These effects of lifelong high level activity seems to act primarily on motor neurons, in particular on those always more active

Use it or Lose It: Tonic Activity of Slow Motoneurons Promotes Their Survival and Preferentially Increases Slow Fiber-Type Groupings in Muscles of Old Lifelong Recreational Sportsmen.

Science.gov (United States)

Mosole, Simone; Carraro, Ugo; Kern, Helmut; Loefler, Stefan; Zampieri, Sandra

2016-09-15

Histochemistry, immuno-histochemistry, gel electrophoresis of single muscle fibers and electromyography of aging muscles and nerves suggest that: i) denervation contributes to muscle atrophy, ii) impaired mobility accelerates the process, and iii) lifelong running protects against loss of motor units. Recent corroborating results on the muscle effects of Functional Electrical Stimulation (FES) of aged muscles will be also mentioned, but we will in particular discuss how and why a lifelong increased physical activity sustains reinnervation of muscle fibers. By analyzing distribution and density of muscle fibers co-expressing fast and slow Myosin Heavy Chains (MHC) we are able to distinguish the transforming muscle fibers due to activity related plasticity, to those that adapt muscle fiber properties to denervation and reinnervation. In muscle biopsies from septuagenarians with a history of lifelong high-level recreational activity we recently observed in comparison to sedentary seniors: 1. decreased proportion of small-size angular myofibers (denervated muscle fibers); 2. considerable increase of fiber-type groupings of the slow type (reinnervated muscle fibers); 3. sparse presence of muscle fibers co-expressing fast and slow MHC. Immuno-histochemical characteristics fluctuate from those with scarce fiber-type modulation and groupings to almost complete transformed muscles, going through a process in which isolated fibers co-expressing fast and slow MHC fill the gaps among fiber groupings. Data suggest that lifelong high-level exercise allows the body to adapt to the consequences of the age-related denervation and that it preserves muscle structure and function by saving otherwise lost muscle fibers through recruitment to different slow motor units. This is an opposite behavior of that described in long term denervated or resting muscles. These effects of lifelong high level activity seems to act primarily on motor neurons, in particular on those always more active

Coupling between myosin head conformation and the thick filament backbone structure.

Science.gov (United States)

Hu, Zhongjun; Taylor, Dianne W; Edwards, Robert J; Taylor, Kenneth A

2017-12-01

The recent high-resolution structure of the thick filament from Lethocerus asynchronous flight muscle shows aspects of thick filament structure never before revealed that may shed some light on how striated muscles function. The phenomenon of stretch activation underlies the function of asynchronous flight muscle. It is most highly developed in flight muscle, but is also observed in other striated muscles such as cardiac muscle. Although stretch activation is likely to be complex, involving more than a single structural aspect of striated muscle, the thick filament itself, would be a prime site for regulatory function because it must bear all of the tension produced by both its associated myosin motors and any externally applied force. Here we show the first structural evidence that the arrangement of myosin heads within the interacting heads motif is coupled to the structure of the thick filament backbone. We find that a change in helical angle of 0.16° disorders the blocked head preferentially within the Lethocerus interacting heads motif. This observation suggests a mechanism for how tension affects the dynamics of the myosin heads leading to a detailed hypothesis for stretch activation and shortening deactivation, in which the blocked head preferentially binds the thin filament followed by the free head when force production occurs. Copyright © 2017 Elsevier Inc. All rights reserved.

Myosin VIIa, harmonin and cadherin 23, three Usher I gene products that cooperate to shape the sensory hair cell bundle

Science.gov (United States)

Boëda, Batiste; El-Amraoui, Aziz; Bahloul, Amel; Goodyear, Richard; Daviet, Laurent; Blanchard, Stéphane; Perfettini, Isabelle; Fath, Karl R.; Shorte, Spencer; Reiners, Jan; Houdusse, Anne; Legrain, Pierre; Wolfrum, Uwe; Richardson, Guy; Petit, Christine

2002-01-01

Deaf-blindness in three distinct genetic forms of Usher type I syndrome (USH1) is caused by defects in myosin VIIa, harmonin and cadherin 23. Despite being critical for hearing, the functions of these proteins in the inner ear remain elusive. Here we show that harmonin, a PDZ domain-containing protein, and cadherin 23 are both present in the growing stereocilia and that they bind to each other. Moreover, we demonstrate that harmonin b is an F-actin-bundling protein, which is thus likely to anchor cadherin 23 to the stereocilia microfilaments, thereby identifying a novel anchorage mode of the cadherins to the actin cytoskeleton. Moreover, harmonin b interacts directly with myosin VIIa, and is absent from the disorganized hair bundles of myosin VIIa mutant mice, suggesting that myosin VIIa conveys harmonin b along the actin core of the developing stereocilia. We propose that the shaping of the hair bundle relies on a functional unit composed of myosin VIIa, harmonin b and cadherin 23 that is essential to ensure the cohesion of the stereocilia. PMID:12485990

FROM SLOW FOOD TO SLOW TOURISM

Directory of Open Access Journals (Sweden)

Bac Dorin Paul

2014-12-01

Full Text Available One of the effects of globalization is the faster pace of our lives. This rhythm can be noticed in all aspects of life: travel, work, shopping, etc. and it has serious negative effects. It has become common knowledge that stress and speed generate serious medical issues. Food and eating habits in the modern world have taken their toll on our health. However, some people took a stand and argued for a new kind of lifestyle. It all started in the field of gastronomy, where a new movement emerged – Slow Food, based on the ideas and philosophy of Carlo Petrini. Slow Food represents an important adversary to the concept of fast food, and is promoting local products, enjoyable meals and healthy food. The philosophy of the Slow Food movement developed in several directions: Cittaslow, slow travel and tourism, slow religion and slow money etc. The present paper will account the evolution of the concept and its development during the most recent years. We will present how the philosophy of slow food was applied in all the other fields it reached and some critical points of view. Also we will focus on the presence of the slow movement in Romania, although it is in a very early stage of development. The main objectives of the present paper are: to present the chronological and ideological evolution of the slow movement; to establish a clear separation of slow travel and slow tourism, as many mistake on for the other; to review the presence of the slow movement in Romania. Regarding the research methodology, information was gathered from relevant academic papers and books and also from interviews and discussions with local entrepreneurs. The research is mostly theoretical and empirical, as slow food and slow tourism are emerging research themes in academic circles.

Actin Filaments and Myosin I Alpha Cooperate with Microtubules for the Movement of LysosomesV⃞

OpenAIRE

Cordonnier, Marie-Neige; Dauzonne, Daniel; Louvard, Daniel; Coudrier, Evelyne

2001-01-01

An earlier report suggested that actin and myosin I alpha (MMIα), a myosin associated with endosomes and lysosomes, were involved in the delivery of internalized molecules to lysosomes. To determine whether actin and MMIα were involved in the movement of lysosomes, we analyzed by time-lapse video microscopy the dynamic of lysosomes in living mouse hepatoma cells (BWTG3 cells), producing green fluorescent protein actin or a nonfunctional domain of MMIα. In GFP-actin cells, lysosomes displayed ...

A comparative study of myosin and its subunits in adult and neonatal-rat hearts and in rat heart cells from young and old cultures.

OpenAIRE

Ghanbari, H A; McCarl, R L

1980-01-01

A possible explanation for the decrease in myosin Ca2+-dependent ATPase activity as rat heart cells age in culture is presented. The subunit structure and enzyme kinetics of myosin from adult and neonatal rat hearts and from rat heart cells of young and old cultures are compared. These studies indicate that the loss in Ca-ATPase activity of myosin from older cultures was an intrinsic property of the myosin itself. Myofibrillar fractions from the indicated four sources showed no qualitative or...

The fungal myosin I is essential for Fusarium toxisome formation

Science.gov (United States)

The mycotoxin deoxynivalenol (DON) is the most frequently detected secondary metabolite produced by Fusarium graminearum and other Fusarium spp. To date, relatively few studies have addressed how mycotoxin biosynthesis occurs in fungal cells. Here we found that myosin I governs translation of DON bi...

A Drosophila model of dominant inclusion body myopathy type 3 shows diminished myosin kinetics that reduce muscle power and yield myofibrillar defects.

Science.gov (United States)

Suggs, Jennifer A; Melkani, Girish C; Glasheen, Bernadette M; Detor, Mia M; Melkani, Anju; Marsan, Nathan P; Swank, Douglas M; Bernstein, Sanford I

2017-06-01

Individuals with inclusion body myopathy type 3 (IBM3) display congenital joint contractures with early-onset muscle weakness that becomes more severe in adulthood. The disease arises from an autosomal dominant point mutation causing an E706K substitution in myosin heavy chain type IIa. We have previously expressed the corresponding myosin mutation (E701K) in homozygous Drosophila indirect flight muscles and recapitulated the myofibrillar degeneration and inclusion bodies observed in the human disease. We have also found that purified E701K myosin has dramatically reduced actin-sliding velocity and ATPase levels. Since IBM3 is a dominant condition, we now examine the disease state in heterozygote Drosophila in order to gain a mechanistic understanding of E701K pathogenicity. Myosin ATPase activities in heterozygotes suggest that approximately equimolar levels of myosin accumulate from each allele. In vitro actin sliding velocity rates for myosin isolated from the heterozygotes were lower than the control, but higher than for the pure mutant isoform. Although sarcomeric ultrastructure was nearly wild type in young adults, mechanical analysis of skinned indirect flight muscle fibers revealed a 59% decrease in maximum oscillatory power generation and an approximately 20% reduction in the frequency at which maximum power was produced. Rate constant analyses suggest a decrease in the rate of myosin attachment to actin, with myosin spending decreased time in the strongly bound state. These mechanical alterations result in a one-third decrease in wing beat frequency and marginal flight ability. With aging, muscle ultrastructure and function progressively declined. Aged myofibrils showed Z-line streaming, consistent with the human heterozygote phenotype. Based upon the mechanical studies, we hypothesize that the mutation decreases the probability of the power stroke occurring and/or alters the degree of movement of the myosin lever arm, resulting in decreased in vitro

A Drosophila model of dominant inclusion body myopathy type 3 shows diminished myosin kinetics that reduce muscle power and yield myofibrillar defects

Directory of Open Access Journals (Sweden)

Jennifer A. Suggs

2017-06-01

Full Text Available Individuals with inclusion body myopathy type 3 (IBM3 display congenital joint contractures with early-onset muscle weakness that becomes more severe in adulthood. The disease arises from an autosomal dominant point mutation causing an E706K substitution in myosin heavy chain type IIa. We have previously expressed the corresponding myosin mutation (E701K in homozygous Drosophila indirect flight muscles and recapitulated the myofibrillar degeneration and inclusion bodies observed in the human disease. We have also found that purified E701K myosin has dramatically reduced actin-sliding velocity and ATPase levels. Since IBM3 is a dominant condition, we now examine the disease state in heterozygote Drosophila in order to gain a mechanistic understanding of E701K pathogenicity. Myosin ATPase activities in heterozygotes suggest that approximately equimolar levels of myosin accumulate from each allele. In vitro actin sliding velocity rates for myosin isolated from the heterozygotes were lower than the control, but higher than for the pure mutant isoform. Although sarcomeric ultrastructure was nearly wild type in young adults, mechanical analysis of skinned indirect flight muscle fibers revealed a 59% decrease in maximum oscillatory power generation and an approximately 20% reduction in the frequency at which maximum power was produced. Rate constant analyses suggest a decrease in the rate of myosin attachment to actin, with myosin spending decreased time in the strongly bound state. These mechanical alterations result in a one-third decrease in wing beat frequency and marginal flight ability. With aging, muscle ultrastructure and function progressively declined. Aged myofibrils showed Z-line streaming, consistent with the human heterozygote phenotype. Based upon the mechanical studies, we hypothesize that the mutation decreases the probability of the power stroke occurring and/or alters the degree of movement of the myosin lever arm, resulting in

Synthesis of total protein (TP) and myosin heavy chain (HC) isozymes in pressure overloaded rabbit hearts

International Nuclear Information System (INIS)

Nagai, R.; Martin, B.J.; Pritzl, N.; Zak, R.; Low, R.B.; Stirewalt, W.S.; Alpert, N.R.; Litten, R.Z.

1986-01-01

Pulmonary artery banding (PO) leads to a rapid increase in right ventricular (RV) weight as well as a shift toward β myosin isozyme. They determined: (1) the contributions of changes in the capacity (RNA content) and efficiency of total protein synthesis to the increase in RV weight; and (2) the relative contributions of translational and pretranslational mechanisms to the shift in myosin HC isotypes. The rates of synthesis in vivo of TP, α- and β-HC were measured by a constant infusion technique using 3 H-leucine. TP synthesis was 7 +/- 2(SD) mg/day in control (RV:367 +/- 70 mg) and was increased by 2.6 fold at day 2 and 2.9 fold at day 4 following PO (p < 0.01). RV RNA content was increased by 83% at day 2 and 103% at day 4 PO (p < 0.05). The efficiency of synthesis (rate/RNA) was also significantly higher at these time points (1.4- and 1.3-fold). β-HC synthesis was 0.6 +/- 0.2 mg/day in control and increased by 2.6 fold at day 2 and 3.5 fold at day 4 following PO. In contrast, the rate of synthesis of α-HC was unchanged. The relative rates of β-HC to total HC synthesis was correlated linearly with the relative levels of β-myosin mRNA as measured by S1 nuclease mapping. They conclude that increases in the proportion of β-HC myosin following PO is due to increases in the relative amount of β-myosin mRNA and therefore involves modulation of a pretranslational mechanism

Myosin XI-Dependent Formation of Tubular Structures from Endoplasmic Reticulum Isolated from Tobacco Cultured BY-2 Cells1[W][OA

Science.gov (United States)

Yokota, Etsuo; Ueda, Haruko; Hashimoto, Kohsuke; Orii, Hidefumi; Shimada, Tomoo; Hara-Nishimura, Ikuko; Shimmen, Teruo

2011-01-01

The reticular network of the endoplasmic reticulum (ER) consists of tubular and lamellar elements and is arranged in the cortical region of plant cells. This network constantly shows shape change and remodeling motion. Tubular ER structures were formed when GTP was added to the ER vesicles isolated from tobacco (Nicotiana tabacum) cultured BY-2 cells expressing ER-localized green fluorescent protein. The hydrolysis of GTP during ER tubule formation was higher than that under conditions in which ER tubule formation was not induced. Furthermore, a shearing force, such as the flow of liquid, was needed for the elongation/extension of the ER tubule. The shearing force was assumed to correspond to the force generated by the actomyosin system in vivo. To confirm this hypothesis, the S12 fraction was prepared, which contained both cytosol and microsome fractions, including two classes of myosins, XI (175-kD myosin) and VIII (BY-2 myosin VIII-1), and ER-localized green fluorescent protein vesicles. The ER tubules and their mesh-like structures were arranged in the S12 fraction efficiently by the addition of ATP, GTP, and exogenous filamentous actin. The tubule formation was significantly inhibited by the depletion of 175-kD myosin from the S12 fraction but not BY-2 myosin VIII-1. Furthermore, a recombinant carboxyl-terminal tail region of 175-kD myosin also suppressed ER tubule formation. The tips of tubules moved along filamentous actin during tubule elongation. These results indicated that the motive force generated by the actomyosin system contributes to the formation of ER tubules, suggesting that myosin XI is responsible not only for the transport of ER in cytoplasm but also for the reticular organization of cortical ER. PMID:21427277

Increased expression of Myosin binding protein H in the skeletal muscle of amyotrophic lateral sclerosis patients.

Science.gov (United States)

Conti, Antonio; Riva, Nilo; Pesca, Mariasabina; Iannaccone, Sandro; Cannistraci, Carlo V; Corbo, Massimo; Previtali, Stefano C; Quattrini, Angelo; Alessio, Massimo

2014-01-01

Amyotrophic lateral sclerosis (ALS) is a severe and fatal neurodegenerative disease of still unknown pathogenesis. Recent findings suggest that the skeletal muscle may play an active pathogenetic role. To investigate ALS's pathogenesis and to seek diagnostic markers, we analyzed skeletal muscle biopsies with the differential expression proteomic approach. We studied skeletal muscle biopsies from healthy controls (CN), sporadic ALS (sALS), motor neuropathies (MN) and myopathies (M). Pre-eminently among several differentially expressed proteins, Myosin binding protein H (MyBP-H) expression in ALS samples was anomalously high. MyBP-H is a component of the thick filaments of the skeletal muscle and has strong affinity for myosin, but its function is still unclear. High MyBP-H expression level was associated with abnormal expression of Rho kinase 2 (ROCK2), LIM domain kinase 1 (LIMK1) and cofilin2, that might affect the actin-myosin interaction. We propose that MyBP-H expression level serves, as a putative biomarker in the skeletal muscle, to discriminate ALS from motor neuropathies, and that it signals the onset of dysregulation in actin-myosin interaction; this in turn might contribute to the pathogenesis of ALS. © 2013 Elsevier B.V. All rights reserved.

Alterations in rat cardiac myosin isozymes induced by whole-body irradiation are prevented by 3,5,3'-L-triiodothyronine

Energy Technology Data Exchange (ETDEWEB)

Litten, R.Z.; Fein, H.G.; Gainey, G.T.; Walden, T.L.; Smallridge, R.C. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

1990-01-01

Changes in cardiac myosin isozymes and serum thyroid hormone levels were investigated in rats following 10 Gy whole-body gamma irradiation. The percent beta-myosin heavy chain increased from 21.3 {plus minus} 1.8 to 28.1 {plus minus} 6.8 (NS) at 3-day postirradiation, 37.7 {plus minus} 1.9 (P less than .001) at 6-day postirradiation, and 43.8 {plus minus} 3.3 (P less than .001) at 9-day postirradiation. Along with the change in myosin isozymes was a significant 53% decrease (P less than .001) in the serum thyroxine (T4) level by day 3 postirradiation, remaining depressed through day 9 postirradiation. The serum 3,5,3'-triiodothyronine (T3) level, however, was normal until day 9, when significant depression was also observed. In contrast, the thyroid-stimulating hormone (TSH) level was significantly increased by fourfold at day 3, returning to near normal values by day 9 postirradiation. Daily injections of physiological doses of T3 (0.3 microgram/100 g body weight) prevented the change in the myosin isozymes following whole-body irradiation. Daily pharmacological injections of T3 (3.0 micrograms/100 g body weight) to the irradiated rats produced a further decrease in the percent beta-myosin heavy chain (below control values) indicating tissue hyperthyroidism. Thus, this study suggests that the change in myosin isozymes following whole-body irradiation is caused by an alteration in thyroid hormone activity.

Stable and dynamic microtubules coordinately shape the myosin activation zone during cytokinetic furrow formation

Science.gov (United States)

Foe, Victoria E.; von Dassow, George

2008-01-01

The cytokinetic furrow arises from spatial and temporal regulation of cortical contractility. To test the role microtubules play in furrow specification, we studied myosin II activation in echinoderm zygotes by assessing serine19-phosphorylated regulatory light chain (pRLC) localization after precisely timed drug treatments. Cortical pRLC was globally depressed before cytokinesis, then elevated only at the equator. We implicated cell cycle biochemistry (not microtubules) in pRLC depression, and differential microtubule stability in localizing the subsequent myosin activation. With no microtubules, pRLC accumulation occurred globally instead of equatorially, and loss of just dynamic microtubules increased equatorial pRLC recruitment. Nocodazole treatment revealed a population of stable astral microtubules that formed during anaphase; among these, those aimed toward the equator grew longer, and their tips coincided with cortical pRLC accumulation. Shrinking the mitotic apparatus with colchicine revealed pRLC suppression near dynamic microtubule arrays. We conclude that opposite effects of stable versus dynamic microtubules focuses myosin activation to the cell equator during cytokinesis. PMID:18955555

A biometric approach to laboratory rodent identification.

Science.gov (United States)

Cameron, Jens; Jacobson, Christina; Nilsson, Kenneth; Rögnvaldsson, Thorsteinn

2007-03-01

Individual identification of laboratory rodents typically involves invasive methods, such as tattoos, ear clips, and implanted transponders. Beyond the ethical dilemmas they may present, these methods may cause pain or distress that confounds research results. The authors describe a prototype device for biometric identification of laboratory rodents that would allow researchers to identify rodents without the complications of other methods. The device, which uses the rodent's ear blood vessel pattern as the identifier, is fast, automatic, noninvasive, and painless.

The Potential of/for 'Slow': Slow Tourists and Slow Destinations

Directory of Open Access Journals (Sweden)

J. Guiver

2016-05-01

Full Text Available Slow tourism practices are nothing new; in fact, they were once the norm and still are for millions of people whose annual holiday is spent camping, staying in caravans, rented accommodation, with friends and relations or perhaps in a second home, who immerse themselves in their holiday environment, eat local food, drink local wine and walk or cycle around the area. So why a special edition about slow tourism? Like many aspects of life once considered normal (such as organic farming or free-range eggs, the emergence of new practices has highlighted differences and prompted a re-evaluation of once accepted practices and values. In this way, the concept of ‘slow tourism’ has recently appeared as a type of tourism that contrasts with many contemporary mainstream tourism practices. It has also been associated with similar trends already ‘branded’ slow: slow food and cittaslow (slow towns and concepts such as mindfulness, savouring and well-being.

Rodent Models for Metabolic Syndrome Research

Directory of Open Access Journals (Sweden)

Sunil K. Panchal

2011-01-01

Full Text Available Rodents are widely used to mimic human diseases to improve understanding of the causes and progression of disease symptoms and to test potential therapeutic interventions. Chronic diseases such as obesity, diabetes and hypertension, together known as the metabolic syndrome, are causing increasing morbidity and mortality. To control these diseases, research in rodent models that closely mimic the changes in humans is essential. This review will examine the adequacy of the many rodent models of metabolic syndrome to mimic the causes and progression of the disease in humans. The primary criterion will be whether a rodent model initiates all of the signs, especially obesity, diabetes, hypertension and dysfunction of the heart, blood vessels, liver and kidney, primarily by diet since these are the diet-induced signs in humans with metabolic syndrome. We conclude that the model that comes closest to fulfilling this criterion is the high carbohydrate, high fat-fed male rodent.

The rodent ultrasound production mechanism.

Science.gov (United States)

Roberts, L H

1975-03-01

Rodents produce two types of sounds, audible and ultrasonic, that differ markedly in physical structure. Studies of sound production in light gases show that whereas the audible cries appear to be produced, as in the case of most other mammals, by vibrating structures in the larynx, the ultrasonic cries are produced by a different mechanism, probably a whistle. 'Bird-call' whistles are shown to have all the properties of rodent ultrasonic cries and to mimic them in almost every detail. Thus it is concluded that rodents have two distinct sound production mechanisms, one for audible cries and one for ultrasonic cries.

Botulinum Toxin Type A Inhibits α-Smooth Muscle Actin and Myosin II Expression in Fibroblasts Derived From Scar Contracture.

Science.gov (United States)

Chen, Minliang; Yan, Tongtong; Ma, Kui; Lai, Linying; Liu, Chang; Liang, Liming; Fu, Xiaobing

2016-09-01

Scar contracture (SC) is one of the most common complications resulting from major burn injuries. Numerous treatments are currently available but they do not always yield excellent therapeutic results. Recent reports suggest that botulinum toxin type A (BTXA) is effective at reducing SC clinically, but the molecular mechanism for this action is unknown. α-Smooth muscle actin (α-SMA) and myosin II are the main components of stress fibers, which are the contractile structures of fibroblasts. The effects of BTXA on α-SMA and myosin II in SC are still unknown. This study aimed to explore the effect of BTXA on α-SMA and myosin II expression in fibroblasts derived from SC and to elucidate its actual mechanism further. Fibroblasts were isolated from tissue specimens of SC. Fibroblasts were cultured in Dulbecco modified Eagle medium with different concentrations of BTXA and their proliferation was analyzed through the tetrazolium-based colorimetric method at 1, 4, and 7 days. Proteins of α-SMA and myosin II were checked using Western blot in fibroblasts treated with different concentrations of BTXA at 1, 4, and 7 days. Fibroblasts without BTXA treatment had a higher proliferation than that in other groups, which indicated that the proliferation of fibroblasts was significantly inhibited by BTXA (P < 0.05). Proteins of α-SMA and myosin II between fibroblasts with BTXA and fibroblasts without BTXA are statistically significant (P < 0.05). These results suggest that BTXA effectively inhibited the growth of fibroblasts derived from SC and reduced the expression of α-SMA and myosin II, which provided theoretical support for the application of BTXA to control SC.

Metastasis-associated protein Mts1 (S100A4) inhibits CK2-mediated phosphorylation and self-assembly of the heavy chain of nonmuscle myosin

DEFF Research Database (Denmark)

Kriajevska, M; Bronstein, I B; Scott, D J

2000-01-01

a regulatory role in the myosin assembly. In the presence of calcium, Mts1 binds at the C-terminal end of the myosin heavy chain close to the site of phosphorylation by protein kinase CK2 (Ser1944). In the present study, we have shown that interaction of Mts1 with the human platelet myosin or C...

Orientation of spin-labeled light chain 2 of myosin heads in muscle fibers.

Science.gov (United States)

Arata, T

1990-07-20

Electron paramagnetic resonance (e.p.r.) spectroscopy has been used to monitor the orientation of spin labels attached rigidly to a reactive SH residue on the light chain 2 (LC2) of myosin heads in muscle fibers. e.p.r. spectra from spin-labeled myosin subfragment-1 (S1), allowed to diffuse into unlabeled rigor (ATP-free) fibers, were roughly approximated by a narrow angular distribution of spin labels centered at 66 degrees relative to the fiber axis, indicating a uniform orientation of S1 bound to actin. On the other hand, spectra from spin-labeled heavy meromyosin (HMM) were roughly approximated by two narrow angular distributions centered at 42 degrees and 66 degrees, suggesting that the LC2 domains of the two HMM heads have different orientations. In contrast to S1 or HMM, the spectra from rigor fibers, in which LC2 of endogenous myosin heads was labeled, showed a random orientation which may be due to distortion imposed by the structure of the filament lattice and the mismatch of the helical periodicities of the thick and thin filaments. However, spectra from the fibers in the presence of ATP analog 5'-adenylyl imidodiphosphate (AMPPNP) were approximated by two narrow angular distributions similar to those obtained with HMM. Thus, AMPPNP may cause the LC2 domain to be less flexible and/or the S2 portion to be more flexible, so as to release the distortion of the LC2 domain and make it return to its natural position. At high ionic strength, AMPPNP disoriented the spin labels as ATP did under relaxing conditions, suggesting that the myosin head is detached from and/or weakly (flexibly) attached to a thin filament.

Altered Right Ventricular Mechanical Properties Are Afterload Dependent in a Rodent Model of Bronchopulmonary Dysplasia

Directory of Open Access Journals (Sweden)

Jitandrakumar R. Patel

2017-10-01

Full Text Available Infants born premature are at increased risk for development of bronchopulmonary dysplasia (BPD, pulmonary hypertension (PH, and ultimately right ventricular (RV dysfunction, which together carry a high risk of neonatal mortality. However, the role alveolar simplification and abnormal pulmonary microvascular development in BPD affects RV contractile properties is unknown. We used a rat model of BPD to examine the effect of hyperoxia-induced PH on RV contractile properties. We measured in vivo RV pressure as well as passive force, maximum Ca2+ activated force, calcium sensitivity of force (pCa50 and rate of force redevelopment (ktr in RV skinned trabeculae isolated from hearts of 21-and 35-day old rats pre-exposed to 21% oxygen (normoxia or 85% oxygen (hyperoxia for 14 days after birth. Systolic and diastolic RV pressure were significantly higher at day 21 in hyperoxia exposed rats compared to normoxia control rats, but normalized by 35 days of age. Passive force, maximum Ca2+ activated force, and calcium sensitivity of force were elevated and cross-bridge cycling kinetics depressed in 21-day old hyperoxic trabeculae, whereas no differences between normoxic and hyperoxic trabeculae were seen at 35 days. Myofibrillar protein analysis revealed that 21-day old hyperoxic trabeculae had increased levels of beta-myosin heavy chain (β-MHC, atrial myosin light chain 1 (aMLC1; often referred to as essential light chain, and slow skeletal troponin I (ssTnI compared to age matched normoxic trabeculae. On the other hand, 35-day old normoxic and hyperoxic trabeculae expressed similar level of α- and β-MHC, ventricular MLC1 and predominantly cTnI. These results suggest that neonatal exposure to hyperoxia increases RV afterload and affect both the steady state and dynamic contractile properties of the RV, likely as a result of hyperoxia-induced expression of β-MHC, delayed transition of slow skeletal TnI to cardiac TnI, and expression of atrial MLC1. These

Real Time RT-PCR with a Newly Designed Set of Promers Confirmed the Presence of 2b and 2x/d Myosim Heavy Chain mRNAs in the Rat Slow Soleus Muscle

Czech Academy of Sciences Publication Activity Database

Žurmanová, Jitka; Půta, F.; Stopková, R.; Soukup, Tomáš

2008-01-01

Roč. 57, č. 6 (2008), s. 973-978 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LC554; GA ČR(CZ) GA305/06/1115; GA ČR(CZ) GA304/08/0256 Grant - others:EC(XE) LSH-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : rat slow soleus muscle * myosin heavy chain isoforms * real time RT-PCR Subject RIV: ED - Physiology Impact factor: 1.653, year: 2008

Effect of 48-h food deprivation on the expressions of myosin heavy-chain isoforms and fiber type-related factors in rats.

Science.gov (United States)

Mizunoya, Wataru; Sawano, Shoko; Iwamoto, Yohei; Sato, Yusuke; Tatsumi, Ryuichi; Ikeuchi, Yoshihide

2013-01-01

The primary aim of this study was to examine the effects of 48-h food deprivation on rat skeletal muscle fiber type, according to myosin heavy-chain (MyHC) isoform composition and some metabolism-related factors in both slow-type dominant and fast-type dominant muscle tissues. Male Wistar rats (7 wk old) were treated with 48-h food deprivation or ad libitum feeding as control. After the treatment, the soleus muscle (slow-type dominant) and the extensor digitorum longus (EDL, fast-type dominant) were excised. We found that 48-h food deprivation did not affect MyHC composition in either the soleus or EDL, compared with fed rats by electrophoretic separation of MyHC isoforms. However, 48-h food deprivation significantly increased the mRNA expression of fast-type MyHC2B in the EDL muscle. Moreover, food deprivation increased fatty acid metabolism, as shown by elevated levels of related serum energy substrates and mRNA expression of mitochondrial uncoupling protein (UCP) 3 and lipoprotein lipase (LPL) in both the soleus and EDL. UCP3 and LPL are generally expressed at higher levels in slow-type fibers. Furthermore, we found that food deprivation significantly decreased the protein amounts of PGC1α and phosphorylated FOXO1, which are known as skeletal muscle fiber type regulators. In conclusion, 48-h food deprivation increased mRNA expression of fast-type MyHC isoform and oxidative metabolism-related factors in EDL, whereas MyHC composition at the protein level did not change in either the soleus or EDL.

Myosin content of single muscle fibers following short-term disuse and active recovery in young and old healthy men

DEFF Research Database (Denmark)

Hvid, Lars G; Brocca, Lorenza; Ørtenblad, Niels

2017-01-01

healthy men. Following disuse, myosin content decreased (p... young and old in both fiber types, with MHC 2a fibers demonstrating an overshooting in young (+31%, pStrong correlations were observed between myosin content and single fiber SF in both young and old, with greater slope steepness in MHC 2a vs 1 fibers indicating an enhanced intrinsic...

Wild Rodent Ectoparasites Collected from Northwestern Iran

Directory of Open Access Journals (Sweden)

Zabihollah Zarei

2017-04-01

Full Text Available Background: Rodents play an important role as reservoir of some pathogens, and the host of some ectoparasites as well. These ectoparasites can transmit rodents’ pathogens to human or animals. The aim of this study was to assess the distribution and infestation load of ectoparasites on rodents in Meshkin-Shahr District, northwestern Iran.Method: Rodents were captured using baited live traps in spring 2014 from Meshkin-Shahr District and were trans­ferred to the laboratory for identification to the species level. Their ectoparasites were collected, mounted and identi­fied.Results: Three rodent species including Meriones persicus (74%, Mus musculus (16.9% and Cricetulus migrato­rius (9% were identified. Among all rodents, 185 specimens (90.69% were infested with a total of 521 ectopara­sites. Overall, 10 arthropods species were collected, including fleas (97.6%, one mite (1.6% and one louse species (0.6% as follows: Xenopsylla nubica, X. astia, X. buxtoni, X. cheopis, Nosopsyllus fasciatus, N. iranus, Cten­ocephalides felis, Ctenophthalmus rettigismiti, Ornithonyssus sp and one species of genus Polyplax. The most prev­alent ectoparasites species was X. nubica (89%.Conclusion: Nearly all rodent species were infested with Xenopsylla species. Monitoring of ectoparasites on infested rodents is very important for awareness and early warning towards control of arthropod-borne diseases.

Characterization of the minimum domain required for targeting budding yeast myosin II to the site of cell division

Directory of Open Access Journals (Sweden)

Tolliday Nicola J

2006-06-01

Full Text Available Abstract Background All eukaryotes with the exception of plants use an actomyosin ring to generate a constriction force at the site of cell division (cleavage furrow during mitosis and meiosis. The structure and filament forming abilities located in the C-terminal or tail region of one of the main components, myosin II, are important for localising the molecule to the contractile ring (CR during cytokinesis. However, it remains poorly understood how myosin II is recruited to the site of cell division and how this recruitment relates to myosin filament assembly. Significant conservation between species of the components involved in cytokinesis, including those of the CR, allows the use of easily genetically manipulated organisms, such as budding yeast (Saccharomyces cerevisiae, in the study of cytokinesis. Budding yeast has a single myosin II protein, named Myo1. Unlike most other class II myosins, the tail of Myo1 has an irregular coiled coil. In this report we use molecular genetics, biochemistry and live cell imaging to characterize the minimum localisation domain (MLD of budding yeast Myo1. Results We show that the MLD is a small region in the centre of the tail of Myo1 and that it is both necessary and sufficient for localisation of Myo1 to the yeast bud neck, the pre-determined site of cell division. Hydrodynamic measurements of the MLD, purified from bacteria or yeast, show that it is likely to exist as a trimer. We also examine the importance of a small region of low coiled coil forming probability within the MLD, which we call the hinge region. Removal of the hinge region prevents contraction of the CR. Using fluorescence recovery after photobleaching (FRAP, we show that GFP-tagged MLD is slightly more dynamic than the GFP-tagged full length molecule but less dynamic than the GFP-tagged Myo1 construct lacking the hinge region. Conclusion Our results define the intrinsic determinant for the localization of budding yeast myosin II and show

Identification and biochemical analysis of Slac2-c/MyRIP as a Rab27A-, myosin Va/VIIa-, and actin-binding protein.

Science.gov (United States)

Kuroda, Taruho S; Fukuda, Mitsunori

2005-01-01

Slac2-c/MyRIP is a specific Rab27A-binding protein that contains an N-terminal synaptotagmin-like protein (Slp) homology domain (SHD, a newly identified GTP-Rab27A-binding motif), but in contrast to the Slp family proteins, it lacks C-terminal tandem C2 domains. In vitro Slac2-c simultaneously directly interacts with both Rab27A and an actin-based motor protein, myosin Va, via its N-terminal SHD and middle region, respectively, consistent with the fact that the overall structure of Slac2-c is similar to that of Slac2-a/melanophilin, a linker protein between Rab27A and myosin Va in the melanosome transport in melanocytes. Unlike Slac2-a, however, the middle region of Slac2-c interacts with two types of myosins, myosin Va and myosin VIIa. In addition, the most C-terminal part of both Slac2-a and Slac2-c functions as an actin-binding domain: it directly interacts with globular and fibrous actin in vitro, and the actin-binding domain of Slac2-a and Slac2-c colocalizes with actin filaments when it is expressed in living cells (i.e., PC12 cells and mouse melanocytes). In this chapter we describe the methods that have been used to analyze the protein-protein interactions of Slac2-c, specifically with Rab27A, myosin Va/VIIa, and actin.

Confinement Sensing and Signal Optimization via Piezo1/PKA and Myosin II Pathways

Directory of Open Access Journals (Sweden)

Wei-Chien Hung

2016-05-01

Full Text Available Summary: Cells adopt distinct signaling pathways to optimize cell locomotion in different physical microenvironments. However, the underlying mechanism that enables cells to sense and respond to physical confinement is unknown. Using microfabricated devices and substrate-printing methods along with FRET-based biosensors, we report that, as cells transition from unconfined to confined spaces, intracellular Ca2+ level is increased, leading to phosphodiesterase 1 (PDE1-dependent suppression of PKA activity. This Ca2+ elevation requires Piezo1, a stretch-activated cation channel. Moreover, differential regulation of PKA and cell stiffness in unconfined versus confined cells is abrogated by dual, but not individual, inhibition of Piezo1 and myosin II, indicating that these proteins can independently mediate confinement sensing. Signals activated by Piezo1 and myosin II in response to confinement both feed into a signaling circuit that optimizes cell motility. This study provides a mechanism by which confinement-induced signaling enables cells to sense and adapt to different physical microenvironments. : Hung et al. demonstrate that a Piezo1-dependent intracellular calcium increase negatively regulates protein kinase A (PKA as cells transit from unconfined to confined spaces. The Piezo1/PKA and myosin II signaling modules constitute two confinement-sensing mechanisms. This study provides a paradigm by which signaling enables cells to sense and adapt to different microenvironments.

Lack of replication for the myosin-18B association with mathematical ability in independent cohorts

Science.gov (United States)

Pettigrew, K A; Fajutrao Valles, S F; Moll, K; Northstone, K; Ring, S; Pennell, C; Wang, C; Leavett, R; Hayiou-Thomas, M E; Thompson, P; Simpson, N H; Fisher, S E; Whitehouse, A J O; Snowling, M J; Newbury, D F; Paracchini, S

2015-01-01

Twin studies indicate that dyscalculia (or mathematical disability) is caused partly by a genetic component, which is yet to be understood at the molecular level. Recently, a coding variant (rs133885) in the myosin-18B gene was shown to be associated with mathematical abilities with a specific effect among children with dyslexia. This association represents one of the most significant genetic associations reported to date for mathematical abilities and the only one reaching genome-wide statistical significance. We conducted a replication study in different cohorts to assess the effect of rs133885 maths-related measures. The study was conducted primarily using the Avon Longitudinal Study of Parents and Children (ALSPAC), (N = 3819). We tested additional cohorts including the York Cohort, the Specific Language Impairment Consortium (SLIC) cohort and the Raine Cohort, and stratified them for a definition of dyslexia whenever possible. We did not observe any associations between rs133885 in myosin-18B and mathematical abilities among individuals with dyslexia or in the general population. Our results suggest that the myosin-18B variant is unlikely to be a main factor contributing to mathematical abilities. PMID:25778778

The effect of the substitution of D{sub 2}O for H{sub 2}O on the degradation of myosin {beta} in solution by heat and by {sup 60}Co {gamma} radiation (1962); Effet de la substitution de D{sub 2}O a H{sub 2}O sur l'alteration de la Myosine B en solution par la chaleur et par les rayons {gamma} du {sup 60}CO (1962)

Energy Technology Data Exchange (ETDEWEB)

Pinset-Harstrom, I.; Fritsch, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-07-01

(1) Alterations of myosin B produced by heat or irradiation are shown to be qualitatively identical as demonstrated by analytical centrifugation. (2) A considerable isotope effect was demonstrated using 75 per cent D{sub 2}O in the solvent. The sensitivity of myosin B to heat and irradiation is discussed in the light of this isotope effect. (3) Polymers appearing upon heat treatment of myosin B seem to be of a very different nature than the polymers occurring alter a similar treatment upon myosin A. Polymers obtained from myosin B can be depolymerized by ATP and they appear in a much narrower temperature range than myosin A polymers. This fact indicates a considerable difference in the activation enthalpies in the two reactions. (authors) [French] (1) Cette etude montre que les alterations de la myosine B provoquees par la chaleur et par l'irradiation aux rayons {gamma} sont - telles qu'elles apparaissent a l'ultracentrifugation analytique - qualitativement semblables. (2) Nous avons observe un effet isotopique considerable de la presence de 75 pour cent de D{sub 2}O dans le solvant sur la sensibilite de la myosine B envers ces deux agents, et nous avons presente une tentative d'explication de ce fait. (3) Les polymeres qui apparaissent apres un traitement par la chaleur de la myosine semblent etre d'une nature tres differente des polymeres que l'on voit apparaitre apres un traitement identique de la myosine A. Ceux obtenus a partir de le myosine B sont depolymerisables par l'intermediaire de l'ATP et apparaissent dans une zone de temperature beaucoup plus etroite que celles de la myosine A. Ce dernier fait indique une difference considerable de l'enthalpie d'activation des deux reactions. (auteurs)

The effect of the substitution of D{sub 2}O for H{sub 2}O on the degradation of myosin {beta} in solution by heat and by {sup 60}Co {gamma} radiation (1962); Effet de la substitution de D{sub 2}O a H{sub 2}O sur l'alteration de la Myosine B en solution par la chaleur et par les rayons {gamma} du {sup 60}CO (1962)

Energy Technology Data Exchange (ETDEWEB)

Pinset-Harstrom, I; Fritsch, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-07-01

(1) Alterations of myosin B produced by heat or irradiation are shown to be qualitatively identical as demonstrated by analytical centrifugation. (2) A considerable isotope effect was demonstrated using 75 per cent D{sub 2}O in the solvent. The sensitivity of myosin B to heat and irradiation is discussed in the light of this isotope effect. (3) Polymers appearing upon heat treatment of myosin B seem to be of a very different nature than the polymers occurring alter a similar treatment upon myosin A. Polymers obtained from myosin B can be depolymerized by ATP and they appear in a much narrower temperature range than myosin A polymers. This fact indicates a considerable difference in the activation enthalpies in the two reactions. (authors) [French] (1) Cette etude montre que les alterations de la myosine B provoquees par la chaleur et par l'irradiation aux rayons {gamma} sont - telles qu'elles apparaissent a l'ultracentrifugation analytique - qualitativement semblables. (2) Nous avons observe un effet isotopique considerable de la presence de 75 pour cent de D{sub 2}O dans le solvant sur la sensibilite de la myosine B envers ces deux agents, et nous avons presente une tentative d'explication de ce fait. (3) Les polymeres qui apparaissent apres un traitement par la chaleur de la myosine semblent etre d'une nature tres differente des polymeres que l'on voit apparaitre apres un traitement identique de la myosine A. Ceux obtenus a partir de le myosine B sont depolymerisables par l'intermediaire de l'ATP et apparaissent dans une zone de temperature beaucoup plus etroite que celles de la myosine A. Ce dernier fait indique une difference considerable de l'enthalpie d'activation des deux reactions. (auteurs)

The force dependence of isometric and concentric potentiation in mouse muscle with and without skeletal myosin light chain kinase.

Science.gov (United States)

Gittings, William; Aggarwal, Harish; Stull, James T; Vandenboom, Rene

2015-01-01

The isometric potentiation associated with myosin phosphorylation is force dependent. The purpose of this study was to assess the influence of a pre-existing period of isometric force on the concentric force potentiation displayed by mouse muscles with and without the ability to phosphorylate myosin. We tested isometric (ISO) and concentric (CON) potentiation, as well as concentric potentiation after isometric force (ISO-CON), in muscles from wild-type (WT) and skeletal myosin light chain kinase-deficient (skMLCK(-/-)) mice. A conditioning stimulus increased (i.e., potentiated) mean concentric force in the ISO-CON and CON conditions to 1.31 ± 0.02 and 1.35 ± 0.02 (WT) and to 1.19 ± 0.02 and 1.21 ± 0.01 (skMLCK(-/-)) of prestimulus levels, respectively (data n = 6-8, p muscles.

Expression of porcine myosin heavy chain 1 gene in Berkshire loins ...

African Journals Online (AJOL)

Expression of porcine myosin heavy chain 1 gene in Berkshire loins with a high pH24 value. Jin Hun Kang, Woo Young Bang, Eun Jung Kwon, Yong Hwa Lee, Da Hye Park, Eun Seok Cho, Min Ji Kim, Jong-Soon Choi, Hwa Chun Park, Beom Young Park, Chul Wook Kim ...

Regulation of nonmuscle myosin II during 3-methylcholanthrene induced dedifferentiation of C2C12 myotubes

Energy Technology Data Exchange (ETDEWEB)

Dey, Sumit K.; Saha, Shekhar; Das, Provas; Das, Mahua R.; Jana, Siddhartha S., E-mail: bcssj@iacs.res.in

2014-08-01

3-Methylcholanthrene (3MC) induces tumor formation at the site of injection in the hind leg of mice within 110 days. Recent reports reveal that the transformation of normal muscle cells to atypical cells is one of the causes for tumor formation, however the molecular mechanism behind this process is not well understood. Here, we show in an in vitro study that 3MC induces fragmentation of multinucleate myotubes into viable mononucleates. These mononucleates form colonies when they are seeded into soft agar, indicative of cellular transformation. Immunoblot analysis reveals that phosphorylation of myosin regulatory light chain (RLC{sub 20}) is 5.6±0.5 fold reduced in 3MC treated myotubes in comparison to vehicle treated myotubes during the fragmentation of myotubes. In contrast, levels of myogenic factors such as MyoD, Myogenin and cell cycle regulators such as Cyclin D, Cyclin E1 remain unchanged as assessed by real-time PCR array and reverse transcriptase PCR analysis, respectively. Interestingly, addition of the myosin light chain kinase inhibitor, ML-7, enhances the fragmentation, whereas phosphatase inhibitor perturbs the 3MC induced fragmentation of myotubes. These results suggest that decrease in RLC{sub 20} phosphorylation may be associated with the fragmentation step of dedifferentiation. - Highlights: • 3-Methylcholanthrene induces fragmentation of C2C12-myotubes. • Dedifferentiation can be divided into two steps – fragmentation and proliferation. • Fragmentation is associated with rearrangement of nonmuscle myosin II. • Genes associated with differentiation and proliferation are not altered during fragmentation. • Phosphorylation of myosin regulatory light chain is reduced during fragmentation.

Template based rodent brain extraction and atlas mapping.

Science.gov (United States)

Weimin Huang; Jiaqi Zhang; Zhiping Lin; Su Huang; Yuping Duan; Zhongkang Lu

2016-08-01

Accurate rodent brain extraction is the basic step for many translational studies using MR imaging. This paper presents a template based approach with multi-expert refinement to automatic rodent brain extraction. We first build the brain appearance model based on the learning exemplars. Together with the template matching, we encode the rodent brain position into the search space to reliably locate the rodent brain and estimate the rough segmentation. With the initial mask, a level-set segmentation and a mask-based template learning are implemented further to the brain region. The multi-expert fusion is used to generate a new mask. We finally combine the region growing based on the histogram distribution learning to delineate the final brain mask. A high-resolution rodent atlas is used to illustrate that the segmented low resolution anatomic image can be well mapped to the atlas. Tested on a public data set, all brains are located reliably and we achieve the mean Jaccard similarity score at 94.99% for brain segmentation, which is a statistically significant improvement compared to two other rodent brain extraction methods.

Acceleration of the sliding movement of actin filaments with the use of a non-motile mutant myosin in in vitro motility assays driven by skeletal muscle heavy meromyosin.

Directory of Open Access Journals (Sweden)

Kohei Iwase

Full Text Available We examined the movement of an actin filament sliding on a mixture of normal and genetically modified myosin molecules that were attached to a glass surface. For this purpose, we used a Dictyostelium G680V mutant myosin II whose release rates of Pi and ADP were highly suppressed relative to normal myosin, leading to a significantly extended life-time of the strongly bound state with actin and virtually no motility. When the mixing ratio of G680V mutant myosin II to skeletal muscle HMM (heavy myosin was 0.01%, the actin filaments moved intermittently. When they moved, their sliding velocities were about two-fold faster than the velocity of skeletal HMM alone. Furthermore, sliding movements were also faster when the actin filaments were allowed to slide on skeletal muscle HMM-coated glass surfaces in the motility buffer solution containing G680V HMM. In this case no intermittent movement was observed. When the actin filaments used were copolymerized with a fusion protein consisting of Dictyostelium actin and Dictyostelium G680V myosin II motor domain, similar faster sliding movements were observed on skeletal muscle HMM-coated surfaces. The filament sliding velocities were about two-fold greater than the velocities of normal actin filaments. We found that the velocity of actin filaments sliding on skeletal muscle myosin molecules increased in the presence of a non-motile G680V mutant myosin motor.

Parathyroid hormone promotes the disassembly of cytoskeletal actin and myosin in cultured osteoblastic cells: Mediation by cyclic AMP

International Nuclear Information System (INIS)

Egan, J.J.; Gronowicz, G.; Rodan, G.A.

1991-01-01

Parathyroid hormone (PTH) alters the shape of osteoblastic cells both in vivo and in vitro. In this study, we examined the effect of PTH on cytoskeletal actin and myosin, estimated by polyacrylamide gel electrophoresis of Triton X-100 (1%) nonextractable proteins. After 2-5 minutes, PTH caused a rapid and transient decrease of 50-60% in polymerized actin and myosin associated with the Triton X-100 nonextractable cytoskeleton. Polymerized actin returned to control levels by 30 min. The PTH effect was dose-dependent with an IC50 of about 1 nM, and was partially inhibited by the (3-34) PTH antagonist. PTH caused a rapid transient rise in cyclic AMP (cAMP) in these cells that peaked at 4 min, while the nadir in cytoskeletal actin and myosin was recorded around 5 min. The intracellular calcium chelator Quin-2/AM (10 microM) also decreased cytoskeletal actin and myosin, to the same extent as did PTH (100 nM). To distinguish between cAMP elevation and Ca++ reduction as mediators of PTH action, we measured the phosphorylation of the 20 kD (PI 4.9) myosin light chain in cells preincubated with [32P]-orthophosphate. The phosphorylation of this protein decreased within 2-3 min after PTH addition and returned to control levels after 5 min. The calcium ionophore A-23187 did not antagonize this PTH effect. Visualization of microfilaments with rhodamine-conjugated phalloidin showed that PTH altered the cytoskeleton by decreasing the number of stress fibers. These changes in the cytoskeleton paralleled changes in the shape of the cells from a spread configuration to a stellate form with retracting processes. The above findings indicate that the alteration in osteoblast shape produced by PTH involve relatively rapid and transient changes in cytoskeletal organization that appear to be mediated by cAMP

Sleep Deprivation and Caffeine Treatment Potentiate Photic Resetting of the Master Circadian Clock in a Diurnal Rodent.

Science.gov (United States)

Jha, Pawan Kumar; Bouâouda, Hanan; Gourmelen, Sylviane; Dumont, Stephanie; Fuchs, Fanny; Goumon, Yannick; Bourgin, Patrice; Kalsbeek, Andries; Challet, Etienne

2017-04-19

Circadian rhythms in nocturnal and diurnal mammals are primarily synchronized to local time by the light/dark cycle. However, nonphotic factors, such as behavioral arousal and metabolic cues, can also phase shift the master clock in the suprachiasmatic nuclei (SCNs) and/or reduce the synchronizing effects of light in nocturnal rodents. In diurnal rodents, the role of arousal or insufficient sleep in these functions is still poorly understood. In the present study, diurnal Sudanian grass rats, Arvicanthis ansorgei , were aroused at night by sleep deprivation (gentle handling) or caffeine treatment that both prevented sleep. Phase shifts of locomotor activity were analyzed in grass rats transferred from a light/dark cycle to constant darkness and aroused in early night or late night. Early night, but not late night, sleep deprivation induced a significant phase shift. Caffeine on its own induced no phase shifts. Both sleep deprivation and caffeine treatment potentiated light-induced phase delays and phase advances in response to a 30 min light pulse, respectively. Sleep deprivation in early night, but not late night, potentiated light-induced c-Fos expression in the ventral SCN. Caffeine treatment in midnight triggered c-Fos expression in dorsal SCN. Both sleep deprivation and caffeine treatment potentiated light-induced c-Fos expression in calbindin-containing cells of the ventral SCN in early and late night. These findings indicate that, in contrast to nocturnal rodents, behavioral arousal induced either by sleep deprivation or caffeine during the sleeping period potentiates light resetting of the master circadian clock in diurnal rodents, and activation of calbindin-containing suprachiasmatic cells may be involved in this effect. SIGNIFICANCE STATEMENT Arousing stimuli have the ability to regulate circadian rhythms in mammals. Behavioral arousal in the sleeping period phase shifts the master clock in the suprachiasmatic nuclei and/or slows down the photic

Blebbistain, a myosin II inhibitor, as a novel strategy to regulate detrusor contractility in a rat model of partial bladder outlet obstruction.

Directory of Open Access Journals (Sweden)

Xinhua Zhang

Full Text Available Partial bladder outlet obstruction (PBOO, a common urologic pathology mostly caused by benign prostatic hyperplasia, can coexist in 40-45% of patients with overactive bladder (OAB and is associated with detrusor overactivity (DO. PBOO that induces DO results in alteration in bladder myosin II type and isoform composition. Blebbistatin (BLEB is a myosin II inhibitor we recently demonstrated potently relaxed normal detrusor smooth muscle (SM and reports suggest varied BLEB efficacy for different SM myosin (SMM isoforms and/or SMM vs nonmuscle myosin (NMM. We hypothesize BLEB inhibition of myosin II as a novel contraction protein targeted strategy to regulate DO. Using a surgically-induced male rat PBOO model, organ bath contractility, competitive and Real-Time-RT-PCR were performed. It was found that obstructed-bladder weight significantly increased 2.74-fold while in vitro contractility of detrusor to various stimuli was impaired ∼50% along with decreased shortening velocity. Obstruction also altered detrusor spontaneous activities with significantly increased amplitude but depressed frequency. PBOO switched bladder from a phasic-type to a more tonic-type SM. Expression of 5' myosin heavy chain (MHC alternatively spliced isoform SM-A (associated with tonic-type SM increased 3-fold while 3' MHC SM1 and essential light chain isoform MLC(17b also exhibited increased relative expression. Total SMMHC expression was decreased by 25% while the expression of NMM IIB (SMemb was greatly increased by 4.5-fold. BLEB was found to completely relax detrusor strips from both sham-operated and PBOO rats pre-contracted with KCl, carbachol or electrical field stimulation although sensitivity was slightly decreased (20% only at lower doses for PBOO. Thus we provide the first thorough characterization of the response of rat bladder myosin to PBOO and demonstrate complete BLEB-induced PBOO bladder SM relaxation. Furthermore, the present study provides valuable

Myosin heavy chain-like localizes at cell contact sites during Drosophila myoblast fusion and interacts in vitro with Rolling pebbles 7

Energy Technology Data Exchange (ETDEWEB)

Bonn, Bettina R.; Rudolf, Anja; Hornbruch-Freitag, Christina; Daum, Gabor; Kuckwa, Jessica; Kastl, Lena; Buttgereit, Detlev [Developmental Biology, Department of Biology, Philipps-Universität Marburg, Karl-von-Frisch-Strasse 8, 35037 Marburg (Germany); Renkawitz-Pohl, Renate, E-mail: renkawit@biologie.uni-marburg.de [Developmental Biology, Department of Biology, Philipps-Universität Marburg, Karl-von-Frisch-Strasse 8, 35037 Marburg (Germany)

2013-02-15

Besides representing the sarcomeric thick filaments, myosins are involved in many cellular transport and motility processes. Myosin heavy chains are grouped into 18 classes. Here we show that in Drosophila, the unconventional group XVIII myosin heavy chain-like (Mhcl) is transcribed in the mesoderm of embryos, most prominently in founder cells (FCs). An ectopically expressed GFP-tagged Mhcl localizes in the growing muscle at cell–cell contacts towards the attached fusion competent myoblast (FCM). We further show that Mhcl interacts in vitro with the essential fusion protein Rolling pebbles 7 (Rols7), which is part of a protein complex established at cell contact sites (Fusion-restricted Myogenic-Adhesive Structure or FuRMAS). Here, branched F-actin is likely needed to widen the fusion pore and to integrate the myoblast into the growing muscle. We show that the localization of Mhcl is dependent on the presence of Rols7, and we postulate that Mhcl acts at the FuRMAS as an actin motor protein. We further show that Mhcl deficient embryos develop a wild-type musculature. We thus propose that Mhcl functions redundantly to other myosin heavy chains in myoblasts. Lastly, we found that the protein is detectable adjacent to the sarcomeric Z-discs, suggesting an additional function in mature muscles. - Highlights: ► The class XVIII myosin encoding gene Mhcl is transcribed in the mesoderm. ► Mhcl localization at contact sites of fusing myoblasts depends on Rols7. ► Mhcl interacts in vitro with Rols7 which is essential for myogenesis. ► Functional redundancy with other myosins is likely as mutants show no muscle defects. ► Mhcl localizes adjacent to Z-discs of sarcomeres and might support muscle integrity.

Myosin heavy chain-like localizes at cell contact sites during Drosophila myoblast fusion and interacts in vitro with Rolling pebbles 7

International Nuclear Information System (INIS)

Bonn, Bettina R.; Rudolf, Anja; Hornbruch-Freitag, Christina; Daum, Gabor; Kuckwa, Jessica; Kastl, Lena; Buttgereit, Detlev; Renkawitz-Pohl, Renate

2013-01-01

Besides representing the sarcomeric thick filaments, myosins are involved in many cellular transport and motility processes. Myosin heavy chains are grouped into 18 classes. Here we show that in Drosophila, the unconventional group XVIII myosin heavy chain-like (Mhcl) is transcribed in the mesoderm of embryos, most prominently in founder cells (FCs). An ectopically expressed GFP-tagged Mhcl localizes in the growing muscle at cell–cell contacts towards the attached fusion competent myoblast (FCM). We further show that Mhcl interacts in vitro with the essential fusion protein Rolling pebbles 7 (Rols7), which is part of a protein complex established at cell contact sites (Fusion-restricted Myogenic-Adhesive Structure or FuRMAS). Here, branched F-actin is likely needed to widen the fusion pore and to integrate the myoblast into the growing muscle. We show that the localization of Mhcl is dependent on the presence of Rols7, and we postulate that Mhcl acts at the FuRMAS as an actin motor protein. We further show that Mhcl deficient embryos develop a wild-type musculature. We thus propose that Mhcl functions redundantly to other myosin heavy chains in myoblasts. Lastly, we found that the protein is detectable adjacent to the sarcomeric Z-discs, suggesting an additional function in mature muscles. - Highlights: ► The class XVIII myosin encoding gene Mhcl is transcribed in the mesoderm. ► Mhcl localization at contact sites of fusing myoblasts depends on Rols7. ► Mhcl interacts in vitro with Rols7 which is essential for myogenesis. ► Functional redundancy with other myosins is likely as mutants show no muscle defects. ► Mhcl localizes adjacent to Z-discs of sarcomeres and might support muscle integrity

Tactile learning in rodents: Neurobiology and neuropharmacology.

Science.gov (United States)

Roohbakhsh, Ali; Shamsizadeh, Ali; Arababadi, Mohammad Kazemi; Ayoobi, Fateme; Fatemi, Iman; Allahtavakoli, Mohammad; Mohammad-Zadeh, Mohammad

2016-02-15

Animal models of learning and memory have been the subject of considerable research. Rodents such as mice and rats are nocturnal animals with poor vision, and their survival depends on their sense of touch. Recent reports have shown that whisker somatosensation is the main channel through which rodents collect and process environmental information. This review describes tactile learning in rodents from a neurobiological and neuropharmacological perspective, and how this is involved in memory-related processes. Copyright © 2016 Elsevier Inc. All rights reserved.

How many food additives are rodent carcinogens?

Science.gov (United States)

Johnson, F M

2002-01-01

One generally assumes that chemical agents added to foods are reasonably free of risks to human health, and practically everyone consumes some additives in his or her food daily throughout life. In the United States, the 1958 Food Additives Amendment to the Federal Food, Drug and Cosmetic Act of 1938 requires food manufacturers to demonstrate the safety of food additives to the Food and Drug Administration (FDA). The Amendment contains a provision that prohibits approval of an additive if it is found to cause cancer in humans or animals. In the present study, data from the National Toxicology Program rodent bioassay (NTPRB) were used to identify a sample of approximately 50 rodent-tested additives and other chemicals added to food that had been evaluated independently of the FDA/food industry. Surprisingly, the sample shows more than 40% of these food chemicals to be carcinogenic in one or more rodent groups. If this percentage is extrapolated to all substances added to food in the United States, it would imply that more than 1000 of such substances are potential rodent carcinogens. The NTP and FDA test guidelines use similar, though not necessarily identical, rodent test procedures, including near lifetime exposures to the maximum tolerated dose. The FDA specifies that test chemicals should be administered by the oral route. However, the oral route includes three methods of delivering chemicals, that is, mixed in the food or water or delivered by stomach tube (gavage). The NTP data show only 1 of 18 food chemicals mixed in the food are rodent carcinogens, but 16 of 23 gavage-administered food chemicals are carcinogenic to rodents. The distribution suggests that among orally delivered chemicals, those administered in the feed will more likely prove to be noncarcinogens than chemicals given by gavage. The rodent data also reveal that effects may vary according to dose and genotype, as well as by route of administration, to further complicate extrapolation to humans

Lead reduces tension development and the myosin ATPase activity of the rat right ventricular myocardium

Directory of Open Access Journals (Sweden)

D.V. Vassallo

2008-09-01

Full Text Available Lead (Pb2+ poisoning causes hypertension, but little is known regarding its acute effects on cardiac contractility. To evaluate these effects, force was measured in right ventricular strips that were contracting isometrically in 45 male Wistar rats (250-300 g before and after the addition of increasing concentrations of lead acetate (3, 7, 10, 30, 70, 100, and 300 µM to the bath. Changes in rate of stimulation (0.1-1.5 Hz, relative potentiation after pauses of 15, 30, and 60 s, effect of Ca2+ concentration (0.62, 1.25, and 2.5 mM, and the effect of isoproterenol (20 ng/mL were determined before and after the addition of 100 µM Pb2+. Effects on contractile proteins were evaluated after caffeine treatment using tetanic stimulation (10 Hz and measuring the activity of the myosin ATPase. Pb2+ produced concentration-dependent force reduction, significant at concentrations greater than 30 µM. The force developed in response to increasing rates of stimulation became smaller at 0.5 and 0.8 Hz. Relative potentiation increased after 100 µM Pb2+ treatment. Extracellular Ca2+ increment and isoproterenol administration increased force development but after 100 µM Pb2+ treatment the force was significantly reduced suggesting an effect of the metal on the sarcolemmal Ca2+ influx. Concentration of 100 µM Pb2+ also reduced the peak and plateau force of tetanic contractions and reduced the activity of the myosin ATPase. Results showed that acute Pb2+ administration, although not affecting the sarcoplasmic reticulum activity, produces a concentration-dependent negative inotropic effect and reduces myosin ATPase activity. Results suggest that acute lead administration reduced myocardial contractility by reducing sarcolemmal calcium influx and the myosin ATPase activity. These results also suggest that lead exposure is hazardous and has toxicological consequences affecting cardiac muscle.

Convergent and Divergent Adaptations of Subterranean Rodents

DEFF Research Database (Denmark)

Fang, Xiaodong

Subterranean rodents comprise approximately 250 species that spend their entire lives in underground, unventilated tunnels, distributed along all continents except Australia and Antarctica. Subterranean rodents escape from predators and extreme climatic fluctuations in their underground habitats,...

Myosin II activity is required for functional leading-edge cells and closure of epidermal sheets in fish skin ex vivo.

Science.gov (United States)

Morita, Toshiyuki; Tsuchiya, Akiko; Sugimoto, Masazumi

2011-09-01

Re-epithelialization in skin wound healing is a process in which epidermal sheets grow and close the wound. Although the actin-myosin system is thought to have a pivotal role in re-epithelialization, its role is not clear. In fish skin, re-epithelialization occurs around 500 μm/h and is 50 times faster than in mammalian skin. We had previously reported that leading-edge cells of the epidermal outgrowth have both polarized large lamellipodia and "purse string"-like actin filament cables in the scale-skin culture system of medaka fish, Oryzias latipes (Cell Tissue Res, 2007). The actin purse-string (APS) is a supracellular contractile machinery in which adherens junctions (AJs) link intracellular myosin II-including actin cables between neighboring cells. In this study, we developed a modified "face-to-face" scale-skin culture system as an ex vivo model to study epidermal wound healing, and examined the role of the actin-myosin system in the rapid re-epithelialization using a myosin II ATPase inhibitor, blebbistatin. A low level of blebbistatin suppressed the formation of APS and induced the dissociation of keratocytes from the leading edge without attenuating the growth of the epidermal sheet or the migration rate of solitary keratocytes. AJs in the superficial layer showed no obvious changes elicited by blebbistatin. However, two epidermal sheets without APSs did not make a closure with each other, which was confirmed by inhibiting the connecting AJs between the superficial layers. These results suggest that myosin II activity is required for functional leading-edge cells and for epidermal closure.

Rodent-borne diseases and their public health importance in Iran.

Directory of Open Access Journals (Sweden)

Mohammad Hasan Rabiee

2018-04-01

Full Text Available Rodents are reservoirs and hosts for several zoonotic diseases such as plague, leptospirosis, and leishmaniasis. Rapid development of industry and agriculture, as well as climate change throughout the globe, has led to change or increase in occurrence of rodent-borne diseases. Considering the distribution of rodents throughout Iran, the aim of this review is to assess the risk of rodent-borne diseases in Iran.We searched Google Scholar, PubMed, Science Direct, Scientific Information Database (SID, and Magiran databases up to September 2016 to obtain articles reporting occurrence of rodent-borne diseases in Iran and extract information from them. Out of 70 known rodent-borne diseases, 34 were reported in Iran: 17 (50% parasitic diseases, 13 (38% bacterial diseases, and 4 (12% viral diseases. Twenty-one out of 34 diseases were reported from both humans and rodents. Among the diseases reported in the rodents of Iran, plague, leishmaniasis, and hymenolepiasis were the most frequent. The most infected rodents were Rattus norvegicus (16 diseases, Mus musculus (14 diseases, Rattus rattus (13 diseases, Meriones persicus (7 diseases, Apodemus spp. (5 diseases, Tatera indica (4 diseases, Meriones libycus (3 diseases, Rhombomys opimus (3 diseases, Cricetulus migratorius (3 diseases, and Nesokia indica (2 diseases.The results of this review indicate the importance of rodent-borne diseases in Iran. Considering notable diversity of rodents and their extensive distribution throughout the country, it is crucial to pay more attention to their role in spreading infectious diseases for better control of the diseases.

Rodent-borne diseases and their public health importance in Iran

Science.gov (United States)

Mahmoudi, Ahmad; Siahsarvie, Roohollah; Kryštufek, Boris; Mostafavi, Ehsan

2018-01-01

Background Rodents are reservoirs and hosts for several zoonotic diseases such as plague, leptospirosis, and leishmaniasis. Rapid development of industry and agriculture, as well as climate change throughout the globe, has led to change or increase in occurrence of rodent-borne diseases. Considering the distribution of rodents throughout Iran, the aim of this review is to assess the risk of rodent-borne diseases in Iran. Methodology/Principal finding We searched Google Scholar, PubMed, Science Direct, Scientific Information Database (SID), and Magiran databases up to September 2016 to obtain articles reporting occurrence of rodent-borne diseases in Iran and extract information from them. Out of 70 known rodent-borne diseases, 34 were reported in Iran: 17 (50%) parasitic diseases, 13 (38%) bacterial diseases, and 4 (12%) viral diseases. Twenty-one out of 34 diseases were reported from both humans and rodents. Among the diseases reported in the rodents of Iran, plague, leishmaniasis, and hymenolepiasis were the most frequent. The most infected rodents were Rattus norvegicus (16 diseases), Mus musculus (14 diseases), Rattus rattus (13 diseases), Meriones persicus (7 diseases), Apodemus spp. (5 diseases), Tatera indica (4 diseases), Meriones libycus (3 diseases), Rhombomys opimus (3 diseases), Cricetulus migratorius (3 diseases), and Nesokia indica (2 diseases). Conclusions/Significance The results of this review indicate the importance of rodent-borne diseases in Iran. Considering notable diversity of rodents and their extensive distribution throughout the country, it is crucial to pay more attention to their role in spreading infectious diseases for better control of the diseases. PMID:29672510

Epidemiology of Leptospira Transmitted by Rodents in Southeast Asia

Science.gov (United States)

Mielcarek, Mathilde; Tatard, Caroline; Chaval, Yannick; Suputtamongkol, Yupin; Buchy, Philippe; Jittapalapong, Sathaporn; Herbreteau, Vincent; Morand, Serge

2014-01-01

Background Leptospirosis is the most common bacterial zoonoses and has been identified as an important emerging global public health problem in Southeast Asia. Rodents are important reservoirs for human leptospirosis, but epidemiological data is lacking. Methodology/Principal Findings We sampled rodents living in different habitats from seven localities distributed across Southeast Asia (Thailand, Lao PDR and Cambodia), between 2009 to 2010. Human isolates were also obtained from localities close to where rodents were sampled. The prevalence of Leptospira infection was assessed by real-time PCR using DNA extracted from rodent kidneys, targeting the lipL32 gene. Sequencing rrs and secY genes, and Multi Locus Variable-number Tandem Repeat (VNTR) analyses were performed on DNA extracted from rat kidneys for Leptospira isolates molecular typing. Four species were detected in rodents, L. borgpetersenii (56% of positive samples), L. interrogans (36%), L. kirschneri (3%) and L. weilli (2%), which were identical to human isolates. Mean prevalence in rodents was approximately 7%, and largely varied across localities and habitats, but not between rodent species. The two most abundant Leptospira species displayed different habitat requirements: L. interrogans was linked to humid habitats (rice fields and forests) while L. borgpetersenii was abundant in both humid and dry habitats (non-floodable lands). Conclusion/Significance L. interrogans and L. borgpetersenii species are widely distributed amongst rodent populations, and strain typing confirmed rodents as reservoirs for human leptospirosis. Differences in habitat requirements for L. interrogans and L. borgpetersenii supported differential transmission modes. In Southeast Asia, human infection risk is not only restricted to activities taking place in wetlands and rice fields as is commonly accepted, but should also include tasks such as forestry work, as well as the hunting and preparation of rodents for consumption, which

Ectoparasites of Rodents Captured in Hamedan, Western Iran

Directory of Open Access Journals (Sweden)

Hamid Zendehfili

2015-10-01

Full Text Available Background: Rodents with a population greater than the entire population of other mammals on earth are the source of economic losses and health conflicts. One of the major health problems with the rodents is their role as reservoir hosts of zoonotic diseases. The aim of this study was to assess the infestation of commensal rodents with ectoparasites in Hamedan City, Western Iran.Methods: The samples were collected by live traps during years 2012–2013. After transferring the samples to the Entomological Laboratory of Hamedan University of Medical Sciences, their ectoparasites were collected andidentified.Results: A total of 171 slides were prepared from 105 captured commensal rodents: Mus musculus, Rattus rattus and R. norvegicus comprising three orders namely Mesostigmata: Hypoaspis (Laelaspis astronomica, Dermanyssius sp, Pachylaelapidae (male. Metastigmata: Rhipicephalus sp and Anoplura: Polyplax spinulosa were recovered in Hamedan City. Seventy (66.6% rodents were found infested with at least one species of ectoparasites.Conclusion: The results of our study indicate that ectoparasites infestation in commensal rodents of Hamedan city is high and more attention by local health authorities is needed to prevent zoonotic diseases.

Polymorphism of myofibrillar proteins of rabbit skeletal-muscle fibres. An electrophoretic study of single fibres.

OpenAIRE

Salviati, G; Betto, R; Danieli Betto, D

1982-01-01

Rabbit predominantly fast-twitch-fibre and predominantly slow-twitch-fibre skeletal muscles of the hind limbs, the psoas, the diaphragm and the masseter muscles were fibre-typed by one-dimensional polyacrylamide-gel electrophoresis of the myofibrillar proteins of chemically skinned single fibres. Investigation of the distribution of fast-twitch-fibre and slow-twitch-fibre isoforms of myosin light chains and the type of myosin heavy chains, based on peptide 'maps' published in Cleveland. Fisch...

Lack of replication for the myosin-18B association with mathematical ability in independent cohorts.

Science.gov (United States)

Pettigrew, K A; Fajutrao Valles, S F; Moll, K; Northstone, K; Ring, S; Pennell, C; Wang, C; Leavett, R; Hayiou-Thomas, M E; Thompson, P; Simpson, N H; Fisher, S E; Whitehouse, A J O; Snowling, M J; Newbury, D F; Paracchini, S

2015-04-01

Twin studies indicate that dyscalculia (or mathematical disability) is caused partly by a genetic component, which is yet to be understood at the molecular level. Recently, a coding variant (rs133885) in the myosin-18B gene was shown to be associated with mathematical abilities with a specific effect among children with dyslexia. This association represents one of the most significant genetic associations reported to date for mathematical abilities and the only one reaching genome-wide statistical significance. We conducted a replication study in different cohorts to assess the effect of rs133885 maths-related measures. The study was conducted primarily using the Avon Longitudinal Study of Parents and Children (ALSPAC), (N = 3819). We tested additional cohorts including the York Cohort, the Specific Language Impairment Consortium (SLIC) cohort and the Raine Cohort, and stratified them for a definition of dyslexia whenever possible. We did not observe any associations between rs133885 in myosin-18B and mathematical abilities among individuals with dyslexia or in the general population. Our results suggest that the myosin-18B variant is unlikely to be a main factor contributing to mathematical abilities. © 2015 The Authors. Genes, Brain and Behavior published by International Behavioural and Neural Genetics Society and John Wiley & Sons Ltd.

Double phosphorylation of the myosin regulatory light chain during rigor mortis of bovine Longissimus muscle.

Science.gov (United States)

Muroya, Susumu; Ohnishi-Kameyama, Mayumi; Oe, Mika; Nakajima, Ikuyo; Shibata, Masahiro; Chikuni, Koichi

2007-05-16

To investigate changes in myosin light chains (MyLCs) during postmortem aging of the bovine longissimus muscle, we performed two-dimensional gel electrophoresis followed by identification with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The results of fluorescent differential gel electrophoresis showed that two spots of the myosin regulatory light chain (MyLC2) at pI values of 4.6 and 4.7 shifted toward those at pI values of 4.5 and 4.6, respectively, by 24 h postmortem when rigor mortis was completed. Meanwhile, the MyLC1 and MyLC3 spots did not change during the 14 days postmortem. Phosphoprotein-specific staining of the gels demonstrated that the MyLC2 proteins at pI values of 4.5 and 4.6 were phosphorylated. Furthermore, possible N-terminal region peptides containing one and two phosphoserine residues were detected in each mass spectrum of the MyLC2 spots at pI values of 4.5 and 4.6, respectively. These results demonstrated that MyLC2 became doubly phosphorylated during rigor formation of the bovine longissimus, suggesting involvement of the MyLC2 phosphorylation in the progress of beef rigor mortis. Bovine; myosin regulatory light chain (RLC, MyLC2); phosphorylation; rigor mortis; skeletal muscle.

A Community-Based Surveillance on Determinants of Rodent Infestation

Directory of Open Access Journals (Sweden)

Hsiu-Hua Pai

2003-01-01

Full Text Available Rodent infestation is an important factor in the transmission of infectious diseases of public health importance. From October to November 1998, surveillance stations were established in 110 boroughs of Kaohsiung City in southern Taiwan. Boroughs were chosen by random sampling 10 boroughs from each of 11 districts (464 boroughs in the city. The extent of rodent infestation was determined by cage trapping. The possibility of applying a community-based control program was evaluated by investigating associated demographic and environmental factors as well as related knowledge, attitudes, and behaviors. A total of 90 rodents were trapped in 41% of the 110 boroughs. Using univariate analyses, 17 factors were significantly associated with rodent infestation. A lack of knowledge that rodent control relies on community cooperation was the most important factor among the seven variables associated with the extent of rodent infestation (OR 3.1 by logistic multiple regression. This revealed the importance of community cooperation in controlling rodent infestation. Moreover, improvement of environmental hygiene associated with garbage problems, such as cleanliness of storage rooms and closets, and the hygiene of empty space and resource recycling stations should not be ignored.

Myosin heavy chain composition of tiger (Panthera tigris) and cheetah (Acinonyx jubatus) hindlimb muscles.

Science.gov (United States)

Hyatt, Jon-Philippe K; Roy, Roland R; Rugg, Stuart; Talmadge, Robert J

2010-01-01

Felids have a wide range of locomotor activity patterns and maximal running speeds, including the very fast cheetah (Acinonyx jubatas), the roaming tiger (Panthera tigris), and the relatively sedentary domestic cat (Felis catus). As previous studies have suggested a relationship between the amount and type of activity and the myosin heavy chain (MHC) isoform composition of a muscle, we assessed the MHC isoform composition of selected hindlimb muscles from these three felid species with differing activity regimens. Using gel electrophoresis, western blotting, histochemistry, and immunohistochemistry with MHC isoform-specific antibodies, we compared the MHC composition in the tibialis anterior, medial gastrocnemius (MG), plantaris (Plt), and soleus muscles of the tiger, cheetah, and domestic cat. The soleus muscle was absent in the cheetah. At least one slow (type I) and three fast (types IIa, IIx, and IIb) MHC isoforms were present in the muscles of each felid. The tiger had a high combined percentage of the characteristically slower isoforms (MHCs I and IIa) in the MG (62%) and the Plt (86%), whereas these percentages were relatively low in the MG (44%) and Plt (55%) of the cheetah. In general, the MHC isoform characteristics of the hindlimb muscles matched the daily activity patterns of these felids: the tiger has daily demands for covering long distances, whereas the cheetah has requirements for speed and power. (c) 2009 Wiley-Liss, Inc.

Connexin 39.9 Protein Is Necessary for Coordinated Activation of Slow-twitch Muscle and Normal Behavior in Zebrafish*

Science.gov (United States)

Hirata, Hiromi; Wen, Hua; Kawakami, Yu; Naganawa, Yuriko; Ogino, Kazutoyo; Yamada, Kenta; Saint-Amant, Louis; Low, Sean E.; Cui, Wilson W.; Zhou, Weibin; Sprague, Shawn M.; Asakawa, Kazuhide; Muto, Akira; Kawakami, Koichi; Kuwada, John Y.

2012-01-01

In many tissues and organs, connexin proteins assemble between neighboring cells to form gap junctions. These gap junctions facilitate direct intercellular communication between adjoining cells, allowing for the transmission of both chemical and electrical signals. In rodents, gap junctions are found in differentiating myoblasts and are important for myogenesis. Although gap junctions were once believed to be absent from differentiated skeletal muscle in mammals, recent studies in teleosts revealed that differentiated muscle does express connexins and is electrically coupled, at least at the larval stage. These findings raised questions regarding the functional significance of gap junctions in differentiated muscle. Our analysis of gap junctions in muscle began with the isolation of a zebrafish motor mutant that displayed weak coiling at day 1 of development, a behavior known to be driven by slow-twitch muscle (slow muscle). We identified a missense mutation in the gene encoding Connexin 39.9. In situ hybridization found connexin 39.9 to be expressed by slow muscle. Paired muscle recordings uncovered that wild-type slow muscles are electrically coupled, whereas mutant slow muscles are not. The further examination of cellular activity revealed aberrant, arrhythmic touch-evoked Ca2+ transients in mutant slow muscle and a reduction in the number of muscle fibers contracting in response to touch in mutants. These results indicate that Connexin 39.9 facilitates the spreading of neuronal inputs, which is irregular during motor development, beyond the muscle cells and that gap junctions play an essential role in the efficient recruitment of slow muscle fibers. PMID:22075003

Allosteric communication in myosin V: from small conformational changes to large directed movements.

Directory of Open Access Journals (Sweden)

M Cecchini

Full Text Available The rigor to post-rigor transition in myosin, a consequence of ATP binding, plays an essential role in the Lymn-Taylor functional cycle because it results in the dissociation of the actomyosin complex after the powerstroke. On the basis of the X-ray structures of myosin V, we have developed a new normal mode superposition model for the transition path between the two states. Rigid-body motions of the various subdomains and specific residues at the subdomain interfaces are key elements in the transition. The allosteric communication between the nucleotide binding site and the U50/L50 cleft is shown to result from local changes due to ATP binding, which induce large amplitude motions that are encoded in the structure of the protein. The triggering event is the change in the interaction of switch I and the P-loop, which is stabilized by ATP binding. The motion of switch I, which is a relatively rigid element of the U50 subdomain, leads directly to a partial opening of the U50/L50 cleft; the latter is expected to weaken the binding of myosin to actin. The calculated transition path demonstrates the nature of the subdomain coupling and offers an explanation for the mutual exclusion of ATP and actin binding. The mechanism of the uncoupling of the converter from the motor head, an essential part of the transition, is elucidated. The origin of the partial untwisting of the central beta-sheet in the rigor to post-rigor transition is described.

Clinical assessment of serum myosin light chain I in patients with dilated cardiomyopathy

Energy Technology Data Exchange (ETDEWEB)

Tsuda, Takashi; Izumi, Tohru; Shibata, Akira (Niigata Univ. (Japan). School of Medicine)

1992-08-01

Serum cardiac myosin light chain I (LCI) levels were quantitated using a radioimmunoassay kit in patients suspected of dilated cardiomyopathy (DCM). In this study, 55 patients were evaluated between 1986 and 1991. They were composed of 40 males and 15 females, and their age was 27-75 years (51[+-]11 years). The patients with renal dysfunction were excluded due to their serum creatinine levels (>2.0 mg/dl). After cardiac catheterization, endomyocardial biopsy and echocardiography, 44 patients were diagnosed as DCM, 2 as ischemic heart disease, 2 as chronic myocarditis, 1 as restrictive cardiomyopathy, 1 as dilated hypertrophic cardiomyopathy, 1 as cardiac amyloidosis, 2 as myopathy, 1 as polymyositis and 1 as hypothyroidism. Only two patients with DCM had elevated LCI. Besides, two patients with myopathy or hypothyroidism had elevated LCI. In the follow-up, one patient died suddenly 6 months later and another showed normal value of LCI four years later. LCI elevation in DCM was not related to either the severity of heart failure or cardiac function and it showed no finding of [sup 201]Tl myocardial defect or elevated CPK. The mechanism for elevated LCI in myopathy is related to a crossreaction with myosin light chain in the skeletal muscle. In hypothyroidism, it may be related to decreased clearance of normal LCI concentration or increased myosin light chain from damaged skeletal muscle. In conclusion, it is evident that the measurement of LCI is not helpful in clinical assessment of patients with DCM, but may be useful in detection of secondary cardiomyopathy. (author).

Clinical assessment of serum myosin light chain I in patients with dilated cardiomyopathy

International Nuclear Information System (INIS)

Tsuda, Takashi; Izumi, Tohru; Shibata, Akira

1992-01-01

Serum cardiac myosin light chain I (LCI) levels were quantitated using a radioimmunoassay kit in patients suspected of dilated cardiomyopathy (DCM). In this study, 55 patients were evaluated between 1986 and 1991. They were composed of 40 males and 15 females, and their age was 27-75 years (51±11 years). The patients with renal dysfunction were excluded due to their serum creatinine levels (>2.0 mg/dl). After cardiac catheterization, endomyocardial biopsy and echocardiography, 44 patients were diagnosed as DCM, 2 as ischemic heart disease, 2 as chronic myocarditis, 1 as restrictive cardiomyopathy, 1 as dilated hypertrophic cardiomyopathy, 1 as cardiac amyloidosis, 2 as myopathy, 1 as polymyositis and 1 as hypothyroidism. Only two patients with DCM had elevated LCI. Besides, two patients with myopathy or hypothyroidism had elevated LCI. In the follow-up, one patient died suddenly 6 months later and another showed normal value of LCI four years later. LCI elevation in DCM was not related to either the severity of heart failure or cardiac function and it showed no finding of 201 Tl myocardial defect or elevated CPK. The mechanism for elevated LCI in myopathy is related to a crossreaction with myosin light chain in the skeletal muscle. In hypothyroidism, it may be related to decreased clearance of normal LCI concentration or increased myosin light chain from damaged skeletal muscle. In conclusion, it is evident that the measurement of LCI is not helpful in clinical assessment of patients with DCM, but may be useful in detection of secondary cardiomyopathy. (author)

Hunting, Food Preparation, and Consumption of Rodents in Lao PDR.

Directory of Open Access Journals (Sweden)

Kanokwan Suwannarong

Full Text Available A cross-sectional study was conducted in 29 villages of Khamkeuth District in Bolikhamxay Province in the Lao PDR during March to May 2013. The study aimed to determine the characteristics associated with rodent consumption and related behaviors among different ethnic groups, ages, and genders. Five-hundred-eighty-four (584 males and females from 18-50 years of age participated in this study. Half of them were Hmong (292, 50% while 152 respondents were Lao-Tai (26% or other ethnic groups (140, 24%. Most of the respondents (79.5% had farming as their main occupation. Prevalences of the studied outcomes were high: 39.9 for hunting or capturing rodents in the previous year, 77.7% for preparing rodents as food, and 86.3% for rodent consumption. Multivariable logistic regression analysis showed that likelihood of these types of rodent contact was more consistently associated with behavioral factors (gathering things from the forest and elsewhere, cultivation-related activities, and taking measures to prevent rodent-borne disease than with socio-demographic, environmental, or cultural factors. The strongest associations were observed for gathering things; these associations were consistently positive and statistically significant. Although this study did not directly assess rodent-borne zoonosis risk, we believe that study findings raise concern that such risk may be substantial in the study area and other similar areas. Further epidemiological studies on the association between rodent-borne disease infection and rodent hunting, preparation for food, and consumption are recommended. Moreover, further studies are needed on the association between these potential exposure factors (i.e., rodent hunting, preparation for food, and consumption and rodent-borne infections, especially among ethnic groups like the Hmong in Lao PDR and those in neighboring countries with similar socio-demographic, environmental, behavioral and cultural contexts.

The importance of subfragment 2 and C-terminus of myosin heavy chain for thick filament assembly in skeletal muscle cells.

Science.gov (United States)

Ojima, Koichi; Oe, Mika; Nakajima, Ikuyo; Shibata, Masahiro; Muroya, Susumu; Chikuni, Koichi; Hattori, Akihito; Nishimura, Takanori

2015-04-01

In skeletal muscle cells, myofibrillar proteins are highly organized into sarcomeres in which thick filaments interdigitate with thin filaments to generate contractile force. The size of thick filaments, which consist mainly of myosin molecules, is strictly controlled. However, little is known about the mechanisms by which myosin molecules assemble into thick filaments. Here, we assessed the ability of each domain of myosin heavy chain (Myh) to form thick filaments. We showed that exogenously expressed subfragment 2 (S2) + light meromyosin (LMM) of Myh was efficiently incorporated into thick filaments in muscle cells, although neither solely expressed S2 nor LMM targeted to thick filaments properly. In nonmuscle COS7 cells, S2+LMM formed more enlarged filaments/speckles than LMM. These results suggest that Myh filament formation is induced by S2 accompanying LMM. We further examined the effects of Myh C-terminus on thick filament assembly. C-terminal deletion mutants were incorporated not into entire thick filaments but rather into restricted regions of thick filaments. Our findings suggest that the elongation of myosin filaments to form thick filaments is regulated by S2 as well as C-terminus of LMM. © 2014 Japanese Society of Animal Science.

Dietary patterns of two herbivorous rodents: and Parotomys brantsii ...

African Journals Online (AJOL)

Frequency of occurrence of plant species in the diets were compared with availability of the plants in the rodents' habitats. Both rodents are generalist herbivores, eating plants species in proportion to the availability in their habitats. Dietary patterns, diversity of diet and degree of overlap between rodent's diets are a function ...

Thermoregulation of the subterranean rodent genus Bathyergus ...

African Journals Online (AJOL)

The thermoregulation of the largest subterranean rodent, genus Bathyergus, comprising two species, B. suillus and B. janetta,occurring in mesic and semiarid habitats respectively, was investigated and compared with that of other subterranean rodents. Both species display low resting metabolic rates and low body ...

A Field Study of Plague and Tularemia in Rodents, Western Iran.

Science.gov (United States)

Mostafavi, Ehsan; Shahraki, Abdolrazagh Hashemi; Japoni-Nejad, Alireza; Esmaeili, Saber; Darvish, Jamshid; Sedaghat, Mohammad Mehdi; Mohammadi, Ali; Mohammadi, Zeinolabedin; Mahmoudi, Ahmad; Pourhossein, Behzad; Ghasemi, Ahmad; Gyuranecz, Miklós; Carniel, Elisabeth

2017-04-01

Kurdistan Province in Iran is a historical focus for plague and tularemia. This study aimed at assessing the current status of these two foci by studying their rodent reservoirs. Rodents were trapped and their ectoparasites were collected. The genus and species of both rodents and ectoparasites were determined. Serological analyses of rodent blood samples were done by enzyme-linked immunosorbent assay for plague and by standard tube agglutination assay for tularemia. Rodent spleen samples were subjected to bacterial culture, microscopic examination, and real-time PCR to search for active plague or tularemia infection. During this study, 245 rodents were trapped, of which the most abundant genera were Apodemus (40%), Mus (24.49%), and Meriones (12.65%). One hundred fifty-three fleas, 37 mites, and 54 ticks were collected on these rodents. The results of all direct and indirect tests were negative for plague. Serological tests were positive for tularemia in 4.8% of trapped rodents. This study is the first report on the presence of tularemia infection in rodents in Western Iran. Since Meriones persicus is a known reservoir for plague and tularemia, and this rodent carried plague and tularemia vectors in Marivan and Sanandaj districts, there is a real potential for the occurrence of these two diseases in this region.

Construction and characterization of the alpha form of a cardiac myosin heavy chain cDNA clone and its developmental expression in the Syrian hamster.

OpenAIRE

Liew, C C; Jandreski, M A

1986-01-01

A cDNA clone, pVHC1, was isolated from a Syrian hamster heart cDNA library and was compared to the rat alpha (pCMHC21) and beta (pCMHC5) ventricular myosin heavy chain cDNA clones. The DNA sequence and amino acid sequence deducted from the DNA show more homology with pCMHC21 than pCMHC5. This indicates that pVHC1 is an alpha ventricular myosin heavy chain cDNA clone. However, even though pVHC1 shows a high degree of nucleotide and amino acid conservation with the rat myosin heavy chain sequen...

Gene transfer, expression, and sarcomeric incorporation of a headless myosin molecule in cardiac myocytes: evidence for a reserve in myofilament motor function

Science.gov (United States)

Vandenboom, Rene; Herron, Todd; Favre, Elizabeth; Albayya, Faris P.

2011-01-01

The purpose of this study was to implement a living myocyte in vitro model system to test whether a motor domain-deleted headless myosin construct could be incorporated into the sarcomere and affect contractility. To this end we used gene transfer to express a “headless” myosin heavy chain (headless-MHC) in complement with the native full-length myosin motors in the cardiac sarcomere. An NH2-terminal Flag epitope was used for unique detection of the motor domain-deleted headless-MHC. Total MHC content (i.e., headless-MHC + endogenous MHC) remained constant, while expression of the headless-MHC in transduced myocytes increased from 24 to 72 h after gene transfer until values leveled off at 96 h after gene transfer, at which time the headless-MHC comprised ∼20% of total MHC. Moreover, immunofluorescence labeling and confocal imaging confirmed expression and demonstrated incorporation of the headless-MHC in the A band of the cardiac sarcomere. Functional measurements in intact myocytes showed that headless-MHC modestly reduced amplitude of dynamic twitch contractions compared with controls (P < 0.05). In chemically permeabilized myocytes, maximum steady-state isometric force and the tension-pCa relationship were unaltered by the headless-MHC. These data suggest that headless-MHC can express to 20% of total myosin and incorporate into the sarcomere yet have modest to no effects on dynamic and steady-state contractile function. This would indicate a degree of functional tolerance in the sarcomere for nonfunctional myosin molecules. PMID:21112946

Vascular O-GlcNAcylation augments reactivity to constrictor stimuli by prolonging phosphorylated levels of the myosin light chain

Energy Technology Data Exchange (ETDEWEB)

Lima, V.V. [Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso, Barra do Garças, MT (Brazil); Lobato, N.S.; Filgueira, F.P. [Curso de Medicina, Setor de Fisiologia Humana, Universidade Federal de Goiás, Jataí, GO (Brazil); Webb, R.C. [Department of Physiology, Georgia Regents University, Augusta, GA (United States); Tostes, R.C. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Giachini, F.R. [Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso, Barra do Garças, MT (Brazil)

2014-08-15

O-GlcNAcylation is a modification that alters the function of numerous proteins. We hypothesized that augmented O-GlcNAcylation levels enhance myosin light chain kinase (MLCK) and reduce myosin light chain phosphatase (MLCP) activity, leading to increased vascular contractile responsiveness. The vascular responses were measured by isometric force displacement. Thoracic aorta and vascular smooth muscle cells (VSMCs) from rats were incubated with vehicle or with PugNAc, which increases O-GlcNAcylation. In addition, we determined whether proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation. PugNAc enhanced phenylephrine (PE) responses in rat aortas (maximal effect, 14.2±2 vs 7.9±1 mN for vehicle, n=7). Treatment with an MLCP inhibitor (calyculin A) augmented vascular responses to PE (13.4±2 mN) and abolished the differences in PE-response between the groups. The effect of PugNAc was not observed when vessels were preincubated with ML-9, an MLCK inhibitor (7.3±2 vs 7.5±2 mN for vehicle, n=5). Furthermore, our data showed that differences in the PE-induced contractile response between the groups were abolished by the activator of AMP-activated protein kinase (AICAR; 6.1±2 vs 7.4±2 mN for vehicle, n=5). PugNAc increased phosphorylation of myosin phosphatase target subunit 1 (MYPT-1) and protein kinase C-potentiated inhibitor protein of 17 kDa (CPI-17), which are involved in RhoA/Rho-kinase-mediated inhibition of myosin phosphatase activity. PugNAc incubation produced a time-dependent increase in vascular phosphorylation of myosin light chain and decreased phosphorylation levels of AMP-activated protein kinase, which decreased the affinity of MLCK for Ca{sup 2+}/calmodulin. Our data suggest that proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation, favoring vascular contraction.

Nuclear myosin is ubiquitously expressed and evolutionary conserved in vertebrates

Czech Academy of Sciences Publication Activity Database

Kahle, Michal; Přidalová, Jarmila; Špaček, M.; Dzijak, Rastislav; Hozák, Pavel

2007-01-01

Roč. 127, č. 2 (2007), s. 139-184 ISSN 0948-6143 R&D Projects: GA ČR GA204/04/0108; GA AV ČR IAA5039202; GA MŠk LC545; GA ČR GD204/05/H023 Institutional research plan: CEZ:AV0Z50390512; CEZ:AV0Z50520514 Keywords : Nuclear myosin I * Transcription * Chromatin Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.893, year: 2007

Uus Multiphonic Rodent

Index Scriptorium Estoniae

2009-01-01

Tartus tegutsenud eksperimentaal-rock-duo Opium Flirt Eestisse jäänud liige Erki Hõbe (paarimees Ervin Trofimov tegutseb Ungaris) annab välja oma teise sooloalbumi nime all Multiphonic Rodent, heliplaadi "Astral Dance" esitluskontsert toimub 5. veebruaril Tallinnas baaris Juuksur

Effects of different activity and inactivity paradigms on myosin heavy chain gene expression in striated muscle

Science.gov (United States)

Baldwin, K. M.; Haddad, F.

2001-01-01

The goal of this mini-review is to summarize findings concerning the role that different models of muscular activity and inactivity play in altering gene expression of the myosin heavy chain (MHC) family of motor proteins in mammalian cardiac and skeletal muscle. This was done in the context of examining parallel findings concerning the role that thyroid hormone (T(3), 3,5,3'-triiodothyronine) plays in MHC expression. Findings show that both cardiac and skeletal muscles of experimental animals are initially undifferentiated at birth and then undergo a marked level of growth and differentiation in attaining the adult MHC phenotype in a T(3)/activity level-dependent fashion. Cardiac MHC expression in small mammals is highly sensitive to thyroid deficiency, diabetes, energy deprivation, and hypertension; each of these interventions induces upregulation of the beta-MHC isoform, which functions to economize circulatory function in the face of altered energy demand. In skeletal muscle, hyperthyroidism, as well as interventions that unload or reduce the weight-bearing activity of the muscle, causes slow to fast MHC conversions. Fast to slow conversions, however, are seen under hypothyroidism or when the muscles either become chronically overloaded or subjected to intermittent loading as occurs during resistance training and endurance exercise. The regulation of MHC gene expression by T(3) or mechanical stimuli appears to be strongly regulated by transcriptional events, based on recent findings on transgenic models and animals transfected with promoter-reporter constructs. However, the mechanisms by which T(3) and mechanical stimuli exert their control on transcriptional processes appear to be different. Additional findings show that individual skeletal muscle fibers have the genetic machinery to express simultaneously all of the adult MHCs, e.g., slow type I and fast IIa, IIx, and IIb, in unique combinations under certain experimental conditions. This degree of

A novel de novo mutation of β-cardiac myosin heavy chain gene ...

Indian Academy of Sciences (India)

2014-08-18

Aug 18, 2014 ... It is one of the most important diseases causing a sud- den death in ... familial HCM encode contractile proteins such as β-cardiac myosin ... A previously healthy 12-year-old boy was admitted to our hospital for .... Maron B. J. 2002 Hypertrophic cardiomyopathy: A systematic review. JAMA 287, 1308–1320.

Rodent management: the man/environment interface

International Nuclear Information System (INIS)

Jackson, W.B.

1978-01-01

Rodents which interact with man generally are regarded as undesirable. Attempts at eliminating such rodents by increasing predation (including traps, microbiological agents, toxicants) have been relatively unsuccessful. Management by environmental manipulation must be basic. This then can be supplemented with predation at critical points where public health, use practices, or imperfections in the system demand. Society mores, practices, and economic considerations also have significant impact on the management system

Sarcomere lattice geometry influences cooperative myosin binding in muscle.

Directory of Open Access Journals (Sweden)

Bertrand C W Tanner

2007-07-01

Full Text Available In muscle, force emerges from myosin binding with actin (forming a cross-bridge. This actomyosin binding depends upon myofilament geometry, kinetics of thin-filament Ca(2+ activation, and kinetics of cross-bridge cycling. Binding occurs within a compliant network of protein filaments where there is mechanical coupling between myosins along the thick-filament backbone and between actin monomers along the thin filament. Such mechanical coupling precludes using ordinary differential equation models when examining the effects of lattice geometry, kinetics, or compliance on force production. This study uses two stochastically driven, spatially explicit models to predict levels of cross-bridge binding, force, thin-filament Ca(2+ activation, and ATP utilization. One model incorporates the 2-to-1 ratio of thin to thick filaments of vertebrate striated muscle (multi-filament model, while the other comprises only one thick and one thin filament (two-filament model. Simulations comparing these models show that the multi-filament predictions of force, fractional cross-bridge binding, and cross-bridge turnover are more consistent with published experimental values. Furthermore, the values predicted by the multi-filament model are greater than those values predicted by the two-filament model. These increases are larger than the relative increase of potential inter-filament interactions in the multi-filament model versus the two-filament model. This amplification of coordinated cross-bridge binding and cycling indicates a mechanism of cooperativity that depends on sarcomere lattice geometry, specifically the ratio and arrangement of myofilaments.

Identification and molecular modelling of a mutation in the motor head domain of myosin VIIA in a family with autosomal dominant hearing impairment (DFNA11)

NARCIS (Netherlands)

Luijendijk, M.W.J.; Wijk, E. van; Bischoff, A.M.L.C.; Krieger, E.; Huygen, P.L.M.; Pennings, R.J.E.; Brunner, H.G.; Cremers, C.W.R.J.; Cremers, F.P.M.; Kremer, J.M.J.

2004-01-01

Myosin VIIA is an unconventional myosin that has been implicated in Usher syndrome type 1B, atypical Usher syndrome, non-syndromic autosomal recessive hearing impairment (DFNB2) and autosomal dominant hearing impairment (DFNA11). Here, we present a family with non-syndromic autosomal dominant

Identification and molecular modelling of a mutation in the motor head domain of myosin VIIA in a family with autosomal dominant hearing impairment (DFNA11).

NARCIS (Netherlands)

Luijendijk, M.W.J.; Wijk, E. van; Bischoff, A.M.L.C.; Krieger, E.; Huygen, P.L.M.; Pennings, R.J.E.; Brunner, H.G.; Cremers, C.W.R.J.; Cremers, F.P.M.; Kremer, J.M.J.

2004-01-01

Myosin VIIA is an unconventional myosin that has been implicated in Usher syndrome type 1B, atypical Usher syndrome, non-syndromic autosomal recessive hearing impairment (DFNB2) and autosomal dominant hearing impairment (DFNA11). Here, we present a family with non-syndromic autosomal dominant

Maintenance of muscle myosin levels in adult C. elegans requires both the double bromodomain protein BET-1 and sumoylation

Directory of Open Access Journals (Sweden)

Kate Fisher

2013-10-01

Attenuation of RAS-mediated signalling is a conserved process essential to control cell proliferation, differentiation, and apoptosis. Cooperative interactions between histone modifications such as acetylation, methylation and sumoylation are crucial for proper attenuation in C. elegans, implying that the proteins recognising these histone modifications could also play an important role in attenuation of RAS-mediated signalling. We sought to systematically identify these proteins and found BET-1. BET-1 is a conserved double bromodomain protein that recognises acetyl-lysines on histone tails and maintains the stable fate of various lineages. Unexpectedly, adults lacking both BET-1 and SUMO-1 are depleted of muscle myosin, an essential component of myofibrils. We also show that this muscle myosin depletion does not occur in all animals at a specific time, but rather that the penetrance of the phenotype increases with age. To gain mechanistic insights into this process, we sought to delay the occurrence of the muscle myosin depletion phenotype and found that it requires caspase activity and MEK-dependent signalling. We also performed transcription profiling on these mutants and found an up-regulation of the FGF receptor, egl-15, a tyrosine kinase receptor acting upstream of MEK. Consistent with a MEK requirement, we could delay the muscle phenotype by systemic or hypodermal knock down of egl-15. Thus, this work uncovered a caspase- and MEK-dependent mechanism that acts specifically on ageing adults to maintain the appropriate net level of muscle myosin.

Design considerations in coiled-coil fusion constructs for the structural determination of a problematic region of the human cardiac myosin rod

Energy Technology Data Exchange (ETDEWEB)

Andreas, Michael P.; Ajay, Gautam; Gellings, Jaclyn A.; Rayment, Ivan (UW)

2017-12-01

X-ray structural determination of segments of the myosin rod has proved difficult because of the strong salt-dependent aggregation properties and repeating pattern of charges on the surface of the coiled-coil that lead to the formation of paracrystals. This problem has been resolved in part through the use of globular assembly domains that improve protein folding and prevent aggregation. The primary consideration now in designing coiled-coil fusion constructs for myosin is deciding where to truncate the coiled-coil and which amino acid residues to include from the folding domain. This is especially important for myosin that contains numerous regions of low predicted coiled-coil propensity. Here we describe the strategy adopted to determine the structure of the region that extends from Arg1677 – Leu1797 that included two areas that do not show a strong sequence signature of a conventional left-handed coiled coil or canonical heptad repeat. This demonstrates again that, with careful choice of fusion constructs, overlapping structures exhibit very similar conformations for the myosin rod fragments in the canonical regions. However, conformational variability is seen around Leu1706 which is a hot spot for cardiomyopathy mutations suggesting that this might be important for function.

Can a native rodent species limit the invasive potential of a non-native rodent species in tropical agroforest habitats?

Science.gov (United States)

Stuart, Alexander M; Prescott, Colin V; Singleton, Grant R

2016-06-01

Little is known about native and non-native rodent species interactions in complex tropical agroecosystems. We hypothesised that the native non-pest rodent Rattus everetti may be competitively dominant over the invasive pest rodent Rattus tanezumi within agroforests. We tested this experimentally by using pulse removal for three consecutive months to reduce populations of R. everetti in agroforest habitat, and assessed over 6 months the response of R. tanezumi and other rodent species. Following removal, R. everetti individuals rapidly immigrated into removal sites. At the end of the study period, R. tanezumi were larger and there was a significant shift in their microhabitat use with respect to the use of ground vegetation cover following the perturbation of R. everetti. Irrespective of treatment, R. tanezumi selected microhabitat with less tree canopy cover, indicative of severely disturbed habitat, whereas R. everetti selected microhabitat with a dense canopy. Our results suggest that sustained habitat disturbance in agroforests favours R. tanezumi, while the regeneration of agroforests towards a more natural state would favour native species and may reduce pest pressure in adjacent crops. In addition, the rapid recolonisation of R. everetti suggests this species would be able to recover from non-target impacts of short-term rodent pest control. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Testing the limits of Rodent Sperm Analysis: azoospermia in an otherwise healthy wild rodent population.

Science.gov (United States)

Tannenbaum, Lawrence V; Thran, Brandolyn H; Willams, Keith J

2009-01-01

By comparing the sperm parameters of small rodents trapped at contaminated terrestrial sites and nearby habitat-matched noncontaminated locations, the patent-pending Rodent Sperm Analysis (RSA) method provides a direct health status appraisal for the maximally chemical-exposed mammalian ecological receptor in the wild. RSA outcomes have consistently allowed for as definitive determinations of receptor health as are possible at the present time, thereby streamlining the ecological risk assessment (ERA) process. Here, we describe the unanticipated discovery, at a contaminated US EPA Superfund National Priorities List site, of a population of Hispid cotton rats (Sigmodon hispidus), with a high percentage of adult males lacking sperm entirely (azoospermia). In light of the RSA method's role in streamlining ERAs and in bringing contaminated Superfund-type site investigations to closure, we consider the consequences of the discovery. The two matters specifically discussed are (1) the computation of a population's average sperm count where azoospermia is present and (2) the merits of the RSA method and its sperm parameter thresholds-for-effect when azoospermia is masked in an otherwise apparently healthy rodent population.

Forecasting rodent outbreaks in Africa

DEFF Research Database (Denmark)

Leirs, Herwig; Verhagen, Ron; Verheyen, Walter

1996-01-01

1. Rainfall data were collated for years preceding historical outbreaks of Mastomys rats in East Africa in order to test the hypothesis that such outbreaks occur after long dry periods. 2. Rodent outbreaks were generally not preceded by long dry periods. 3. Population dynamics of Mastomys...... natalensis rats in Tanzania are significantly affected by the distribution of rainfall during the rainy season. 4. All previous rodent outbreaks in Tanzania were preceded by abundant rainfall early in the rainy season, i.e, towards the end of the year. 5. A flow chart is constructed to assess the likelihood...

Old World hantaviruses in rodents in New Orleans, Louisiana.

Science.gov (United States)

Cross, Robert W; Waffa, Bradley; Freeman, Ashley; Riegel, Claudia; Moses, Lina M; Bennett, Andrew; Safronetz, David; Fischer, Elizabeth R; Feldmann, Heinz; Voss, Thomas G; Bausch, Daniel G

2014-05-01

Seoul virus, an Old World hantavirus, is maintained in brown rats and causes a mild form of hemorrhagic fever with renal syndrome (HFRS) in humans. We captured rodents in New Orleans, Louisiana and tested them for the presence of Old World hantaviruses by reverse transcription polymerase chain reaction (RT-PCR) with sequencing, cell culture, and electron microscopy; 6 (3.4%) of 178 rodents captured--all brown rats--were positive for a Seoul virus variant previously coined Tchoupitoulas virus, which was noted in rodents in New Orleans in the 1980s. The finding of Tchoupitoulas virus in New Orleans over 25 years since its first discovery suggests stable endemicity in the city. Although the degree to which this virus causes human infection and disease remains unknown, repeated demonstration of Seoul virus in rodent populations, recent cases of laboratory-confirmed HFRS in some US cities, and a possible link with hypertensive renal disease warrant additional investigation in both rodents and humans.

The local expression of adult chicken heart myosins during development. II. Ventricular conducting tissue

NARCIS (Netherlands)

Sanders, E.; de Groot, I. J.; Geerts, W. J.; de Jong, F.; van Horssen, A. A.; Los, J. A.; Moorman, A. F.

1986-01-01

The development of the ventricular conducting tissue of the embryonic chicken heart has been studied using a previous finding that morphologically recognizable atrial conducting tissue coexpresses the atrial and the ventricular myosin isoforms. It is found that, by these criteria, at 9 days part of

Lassa fever or lassa hemorrhagic fever risk to humans from rodent-borne zoonoses.

Science.gov (United States)

El-Bahnasawy, Mamdouh M; Megahed, Laila Abdel-Mawla; Abdalla Saleh, Hala Ahmed; Morsy, Tosson A

2015-04-01

Viral hemorrhagic fevers (VHFs) typically manifest as rapidly progressing acute febrile syndromes with profound hemorrhagic manifestations and very high fatality rates. Lassa fever, an acute hemorrhagic fever characterized by fever, muscle aches, sore throat, nausea, vomiting, diarrhea and chest and abdominal pain. Rodents are important reservoirs of rodent-borne zoonosis worldwide. Transmission rodents to humans occur by aerosol spread, either from the genus Mastomys rodents' excreta (multimammate rat) or through the close contact with infected patients (nosocomial infection). Other rodents of the genera Rattus, Mus, Lemniscomys, and Praomys are incriminated rodents hosts. Now one may ask do the rodents' ectoparasites play a role in Lassa virus zoonotic transmission. This paper summarized the update knowledge on LHV; hopping it might be useful to the clinicians, nursing staff, laboratories' personals as well as those concerned zoonoses from rodents and rodent control.

Microgenomic analysis in skeletal muscle: expression signatures of individual fast and slow myofibers.

Directory of Open Access Journals (Sweden)

Francesco Chemello

Full Text Available BACKGROUND: Skeletal muscle is a complex, versatile tissue composed of a variety of functionally diverse fiber types. Although the biochemical, structural and functional properties of myofibers have been the subject of intense investigation for the last decades, understanding molecular processes regulating fiber type diversity is still complicated by the heterogeneity of cell types present in the whole muscle organ. METHODOLOGY/PRINCIPAL FINDINGS: We have produced a first catalogue of genes expressed in mouse slow-oxidative (type 1 and fast-glycolytic (type 2B fibers through transcriptome analysis at the single fiber level (microgenomics. Individual fibers were obtained from murine soleus and EDL muscles and initially classified by myosin heavy chain isoform content. Gene expression profiling on high density DNA oligonucleotide microarrays showed that both qualitative and quantitative improvements were achieved, compared to results with standard muscle homogenate. First, myofiber profiles were virtually free from non-muscle transcriptional activity. Second, thousands of muscle-specific genes were identified, leading to a better definition of gene signatures in the two fiber types as well as the detection of metabolic and signaling pathways that are differentially activated in specific fiber types. Several regulatory proteins showed preferential expression in slow myofibers. Discriminant analysis revealed novel genes that could be useful for fiber type functional classification. CONCLUSIONS/SIGNIFICANCE: As gene expression analyses at the single fiber level significantly increased the resolution power, this innovative approach would allow a better understanding of the adaptive transcriptomic transitions occurring in myofibers under physiological and pathological conditions.

The 133-kDa N-terminal domain enables myosin 15 to maintain mechanotransducing stereocilia and is essential for hearing

Science.gov (United States)

Fang, Qing; Indzhykulian, Artur A; Mustapha, Mirna; Riordan, Gavin P; Dolan, David F; Friedman, Thomas B; Belyantseva, Inna A; Frolenkov, Gregory I; Camper, Sally A; Bird, Jonathan E

2015-01-01

The precise assembly of inner ear hair cell stereocilia into rows of increasing height is critical for mechanotransduction and the sense of hearing. Yet, how the lengths of actin-based stereocilia are regulated remains poorly understood. Mutations of the molecular motor myosin 15 stunt stereocilia growth and cause deafness. We found that hair cells express two isoforms of myosin 15 that differ by inclusion of an 133-kDa N-terminal domain, and that these isoforms can selectively traffic to different stereocilia rows. Using an isoform-specific knockout mouse, we show that hair cells expressing only the small isoform remarkably develop normal stereocilia bundles. However, a critical subset of stereocilia with active mechanotransducer channels subsequently retracts. The larger isoform with the 133-kDa N-terminal domain traffics to these specialized stereocilia and prevents disassembly of their actin core. Our results show that myosin 15 isoforms can navigate between functionally distinct classes of stereocilia, and are independently required to assemble and then maintain the intricate hair bundle architecture. DOI: http://dx.doi.org/10.7554/eLife.08627.001 PMID:26302205

A programmable DNA origami nanospring that reveals force-induced adjacent binding of myosin VI heads.

Science.gov (United States)

Iwaki, M; Wickham, S F; Ikezaki, K; Yanagida, T; Shih, W M

2016-12-12

Mechanosensitive biological nanomachines such as motor proteins and ion channels regulate diverse cellular behaviour. Combined optical trapping with single-molecule fluorescence imaging provides a powerful methodology to clearly characterize the mechanoresponse, structural dynamics and stability of such nanomachines. However, this system requires complicated experimental geometry, preparation and optics, and is limited by low data-acquisition efficiency. Here we develop a programmable DNA origami nanospring that overcomes these issues. We apply our nanospring to human myosin VI, a mechanosensory motor protein, and demonstrate nanometre-precision single-molecule fluorescence imaging of the individual motor domains (heads) under force. We observe force-induced transitions of myosin VI heads from non-adjacent to adjacent binding, which correspond to adapted roles for low-load and high-load transport, respectively. Our technique extends single-molecule studies under force and clarifies the effect of force on biological processes.

Expression of smooth muscle and non-muscle myosin heavy chain isoforms in cultured vascular smooth muscle cells

International Nuclear Information System (INIS)

Rovner, A.S.; Murphy, R.A.; Owens, G.K.

1986-01-01

Immunocytochemical studies of cultured smooth muscle cells (SMCs) have disagreed on the nature of myosin expression. This investigation was undertaken to test for the presence of heterogeneous myosin heavy chain (MHC) isoforms in cell culture as a possible explanation for these results. Previously, Rovner et al. detected two MHCs in intact smooth muscles which differed in molecular weight by ca. 4000 daltons (SM1 and SM2) using a 3-4% acrylamide gradient SDS gel system. When sub-confluent primary cultures of rat aorta SMCs were assayed by this system, SM1 and SM2 were seen, along with large amounts of a third, unique MHC, NM, which closely resembled the MHC from human platelet in size and antigenicity. Data from 35 S-methionine autoradiograms showed that the log growth phase SMC cultures were producing almost exclusively NM, but the growth arrest, post-confluent cultures synthesized increased relative amounts of the SM MHC forms and contained comparable amounts of SM1, SM2, and NM. The same patterns of MHC synthesis were seen in sub-passaged SMCs. The expression of the SM-specific forms of myosin in quiescent, post-confluent cultures parallels that of smooth muscle actin suggesting that density induced growth arrest promotes cytodifferentiation in cultured vascular SMCs

Neurobiology of rodent self-grooming and its value for translational neuroscience.

Science.gov (United States)

Kalueff, Allan V; Stewart, Adam Michael; Song, Cai; Berridge, Kent C; Graybiel, Ann M; Fentress, John C

2016-01-01

Self-grooming is a complex innate behaviour with an evolutionarily conserved sequencing pattern and is one of the most frequently performed behavioural activities in rodents. In this Review, we discuss the neurobiology of rodent self-grooming, and we highlight studies of rodent models of neuropsychiatric disorders--including models of autism spectrum disorder and obsessive compulsive disorder--that have assessed self-grooming phenotypes. We suggest that rodent self-grooming may be a useful measure of repetitive behaviour in such models, and therefore of value to translational psychiatry. Assessment of rodent self-grooming may also be useful for understanding the neural circuits that are involved in complex sequential patterns of action.

The IQ motif drives the nuclear translocation of nuclear myosin I

Czech Academy of Sciences Publication Activity Database

Dzijak, Rastislav; Yildirim, Sukriye; Kahle, Michal; Hozák, Pavel

2008-01-01

Roč. 275, č. 1 (2008), s. 67-67 E-ISSN 1742-4658. [FEBS Congress /33rd/, IUBMB conference /11th/. 28.06.2008-03.07.2008, Athens] R&D Projects: GA MŠk LC545; GA ČR(CZ) GA204/07/1592 Grant - others:GAČR(CZ) GD204/05/H023 Program:GD Institutional research plan: CEZ:AV0Z50520514 Keywords : nuclear myosin * nuclear transport Subject RIV: EB - Genetics ; Molecular Biology

Is enteral administration of fluorine-18-fluorodeoxyglucose (F-18 FDG) a palatable alternative to IV injection? Pre-clinical evaluation in normal rodents

Energy Technology Data Exchange (ETDEWEB)

Higashi, T. E-mail: higashi@kuhp.kyoto-u.ac.jp; Fisher, S.J.; Nakada, K.; Romain, D.J.; Wahl, R.L

2002-04-01

To establish effective methods of enteral 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) administration, the efficiency of FDG absorption in the gastrointestinal tracts following enteral administrations was evaluated using the FDG biodistribution in normal rodents, in combination with various fasting conditions and FDG diluents. The blood FDG curve using hypotonic solution showed a rapid increase, while that in iso- and hypertonic groups showed slow rises. Brain FDG uptake had a close positive correlation with blood AUC (area under curve) and an inverse relationship with the stomach contents.

Is enteral administration of fluorine-18-fluorodeoxyglucose (F-18 FDG) a palatable alternative to IV injection? Pre-clinical evaluation in normal rodents

International Nuclear Information System (INIS)

Higashi, T.; Fisher, S.J.; Nakada, K.; Romain, D.J.; Wahl, R.L.

2002-01-01

To establish effective methods of enteral 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) administration, the efficiency of FDG absorption in the gastrointestinal tracts following enteral administrations was evaluated using the FDG biodistribution in normal rodents, in combination with various fasting conditions and FDG diluents. The blood FDG curve using hypotonic solution showed a rapid increase, while that in iso- and hypertonic groups showed slow rises. Brain FDG uptake had a close positive correlation with blood AUC (area under curve) and an inverse relationship with the stomach contents

Technetium-99m labeling of antibodies to cardiac myosin Fab and to human fibrinogen

International Nuclear Information System (INIS)

Khaw, B.A.; Strauss, H.W.; Carvalho, A.; Locke, E.; Gold, H.K.; Haber, E.

1982-01-01

A method of labeling biologically active labile macromolecules, such as human fibrinogen (HF) and anticardiac-myosin Fab (AM-Fab), with Tc-99m at neutral pH was developed. This method uses dithionite reduction of pertechnetate and subsequent labeling to test the method with acid-labile macromolecules. Complexes of diethylene triamine pentaacetic acid with macromolecules such as human fibrinogen (D-HF) and anticardiac-myosin Fab (D-AM-Fab) were labeled and utilized in in vitro and in vivo studies. In biodistribution studies, the Tc-99m D-HF had a two-component blood clearance (half-times 1 hr and 15 hr) and was 80-88% coagulable. The Tc-99m AM-Fab retained its immunoreactivity as tested by affinity chromatography; also during in vivo localization in experimental myocardial infarction. This labeling technique provides an easy and efficient approach to the Tc-99m labeling of other biologically active and acid-labile macromolecules

Clot retraction is mediated by factor XIII-dependent fibrin-αIIbβ3-myosin axis in platelet sphingomyelin-rich membrane rafts.

Science.gov (United States)

Kasahara, Kohji; Kaneda, Mizuho; Miki, Toshiaki; Iida, Kazuko; Sekino-Suzuki, Naoko; Kawashima, Ikuo; Suzuki, Hidenori; Shimonaka, Motoyuki; Arai, Morio; Ohno-Iwashita, Yoshiko; Kojima, Soichi; Abe, Mitsuhiro; Kobayashi, Toshihide; Okazaki, Toshiro; Souri, Masayoshi; Ichinose, Akitada; Yamamoto, Naomasa

2013-11-07

Membrane rafts are spatially and functionally heterogenous in the cell membrane. We observed that lysenin-positive sphingomyelin (SM)-rich rafts are identified histochemically in the central region of adhered platelets where fibrin and myosin are colocalized on activation by thrombin. The clot retraction of SM-depleted platelets from SM synthase knockout mouse was delayed significantly, suggesting that platelet SM-rich rafts are involved in clot retraction. We found that fibrin converted by thrombin translocated immediately in platelet detergent-resistant membrane (DRM) rafts but that from Glanzmann's thrombasthenic platelets failed. The fibrinogen γ-chain C-terminal (residues 144-411) fusion protein translocated to platelet DRM rafts on thrombin activation, but its mutant that was replaced by A398A399 at factor XIII crosslinking sites (Q398Q399) was inhibited. Furthermore, fibrin translocation to DRM rafts was impaired in factor XIII A subunit-deficient mouse platelets, which show impaired clot retraction. In the cytoplasm, myosin translocated concomitantly with fibrin translocation into the DRM raft of thrombin-stimulated platelets. Furthermore, the disruption of SM-rich rafts by methyl-β-cyclodextrin impaired myosin activation and clot retraction. Thus, we propose that clot retraction takes place in SM-rich rafts where a fibrin-αIIbβ3-myosin complex is formed as a primary axis to promote platelet contraction.

Slow Movement/Slow University: Critical Engagements. Introduction to the Thematic Section

Directory of Open Access Journals (Sweden)

Maggie O'Neill

2014-09-01

Full Text Available This thematic section emerged from two seminars that took place at Durham University in England in November 2013 and March 2014 on the possibilities for thinking through what a change movement towards slow might mean for the University. Slow movements have emerged in relation to a number of topics: Slow food, Citta slow and more recently, slow science. What motivated us in the seminars was to explore how far these movements could help us address the acceleration and intensification of work within our own and other universities, and indeed, what new learning, research, philosophies, practices, structures and governance might emerge. This editorial introduction presents the concept of the "slow university" and introduces our critical engagements with slow. The articles presented here interrogate the potentialities, challenges, problems and pitfalls of the slow university in an era of corporate culture and management rationality. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1403166

Specific nuclear localizing sequence directs two myosin isoforms to the cell nucleus in calmodulin-sensitive manner.

Science.gov (United States)

Dzijak, Rastislav; Yildirim, Sukriye; Kahle, Michal; Novák, Petr; Hnilicová, Jarmila; Venit, Tomáš; Hozák, Pavel

2012-01-01

Nuclear myosin I (NM1) was the first molecular motor identified in the cell nucleus. Together with nuclear actin, they participate in crucial nuclear events such as transcription, chromatin movements, and chromatin remodeling. NM1 is an isoform of myosin 1c (Myo1c) that was identified earlier and is known to act in the cytoplasm. NM1 differs from the "cytoplasmic" myosin 1c only by additional 16 amino acids at the N-terminus of the molecule. This amino acid stretch was therefore suggested to direct NM1 into the nucleus. We investigated the mechanism of nuclear import of NM1 in detail. Using over-expressed GFP chimeras encoding for truncated NM1 mutants, we identified a specific sequence that is necessary for its import to the nucleus. This novel nuclear localization sequence is placed within calmodulin-binding motif of NM1, thus it is present also in the Myo1c. We confirmed the presence of both isoforms in the nucleus by transfection of tagged NM1 and Myo1c constructs into cultured cells, and also by showing the presence of the endogenous Myo1c in purified nuclei of cells derived from knock-out mice lacking NM1. Using pull-down and co-immunoprecipitation assays we identified importin beta, importin 5 and importin 7 as nuclear transport receptors that bind NM1. Since the NLS sequence of NM1 lies within the region that also binds calmodulin we tested the influence of calmodulin on the localization of NM1. The presence of elevated levels of calmodulin interfered with nuclear localization of tagged NM1. We have shown that the novel specific NLS brings to the cell nucleus not only the "nuclear" isoform of myosin I (NM1 protein) but also its "cytoplasmic" isoform (Myo1c protein). This opens a new field for exploring functions of this molecular motor in nuclear processes, and for exploring the signals between cytoplasm and the nucleus.

Multiple Co-infections of Rodents with Hantaviruses, Leptospira, and Babesia in Croatia

Science.gov (United States)

Turk, Nenad; Korva, Miša; Margaletić, Josip; Beck, Relja; Vucelja, Marko; Habuš, Josipa; Svoboda, Petra; Županc, Tatjana Avšič; Henttonen, Heikki; Markotić, Alemka

2012-01-01

Abstract Hantaviruses, Leptospira spp., and Babesia spp. are rodent-borne pathogens present worldwide. We studied multiple co-infections of small rodents in Croatia with all three pathogens. Twenty-eight Apodemus flavicollis and 16 Myodes glareolus were tested for the presence of hantavirus RNA by real-time RT-PCR, Leptospira strains by renoculture method and Babesia DNA by PCR. Anti-hantavirus antibodies and anti-Leptospira antibodies were detected by serological methods. Very high infection rates with each pathogen were found in A. flavicollis: 20 of 28 rodents (71%) were infected with Dobrava virus, 13 rodents (46%) were infected with Leptospira, and 5 rodents (18%) were infected with Babesia. Multiple co-infections with all three pathogens were found in 3 of 28 (11%) A. flavicollis animals, suggesting that the same rodent host can be infected with several pathogens at the same time. Dual infections with both hantaviruses and Leptospira were found in 7 of 44 rodents (16%), with hantaviruses and Babesia in 2 rodents (5%), and double infection with both Leptospira and Babesia were found in 1 rodent (2%). Since hantaviruses, Leptospira, and Babesia have similar geographical distributions, it is to be expected that in other parts of the world multiple co-infections, representing a serious threat to public health, can be found. PMID:22217170

Improved protocols for the study of urinary electrolyte excretion and blood pressure in rodents: use of gel food and stepwise changes in diet composition.

Science.gov (United States)

Nizar, Jonathan M; Bouby, Nadine; Bankir, Lise; Bhalla, Vivek

2018-06-01

Many experimental protocols in rodents require the comparison of groups that are fed different diets. Changes in dietary electrolyte and/or fat content can influence food intake, which can potentially introduce bias or confound the results. Unpalatable diets slow growth or cause weight loss, which is exacerbated by housing the animals in individual metabolic cages or by surgery. For balance studies in mice, small changes in body weight and food intake and low urinary flow can amplify these challenges. Powder food can be administered as gel with the addition of a desired amount of water, electrolytes, drugs (if any), and a small amount of agar. We describe here how the use of gel food to vary water, Na, K, and fat content can reduce weight loss and improve reproducibility of intake, urinary excretion, and blood pressure in rodents. In addition, mild food restriction reduces the interindividual variability and intergroup differences in food intake and associated variables, thus improving the statistical power of an experiment. Finally, we also demonstrate the advantages of using gel food for weight-based drug dosing. These protocols can improve the accuracy and reproducibility of experimental data where dietary manipulations are needed and are especially advisable in rodent studies related to water balance, obesity, and blood pressure.

Leptospira and rodents in Cambodia : environmental determinants of infection

OpenAIRE

Ivanova, S.; Herbreteau, Vincent; Blasdell, K.; Chaval, Y.; Buchy, P.; Guillard, B.; Morand, S.

2012-01-01

We investigated infection of rodents and shrews by Leptospira spp. in two localities of Cambodia (Veal Renh, Kaev Seima) and in four types of habitat (forests, non-flooded lands, lowland rain-fed paddy fields, houses) during the wet and the dry seasons. Habitat preference was common, and rodent and shrew species were found only in houses or in rain-fed paddy fields or in forests. Among 649 small mammals trapped belonging to 12 rodent species and 1 shrew species, 71 of 642 animals tested were ...

Myosin II Motor Activity in the Lateral Amygdala Is Required for Fear Memory Consolidation

Science.gov (United States)

Gavin, Cristin F.; Rubio, Maria D.; Young, Erica; Miller, Courtney; Rumbaugh, Gavin

2012-01-01

Learning induces dynamic changes to the actin cytoskeleton that are required to support memory formation. However, the molecular mechanisms that mediate filamentous actin (F-actin) dynamics during learning and memory are poorly understood. Myosin II motors are highly expressed in actin-rich growth structures including dendritic spines, and we have…

Tularemia and plague survey in rodents in an earthquake zone in southeastern Iran

Science.gov (United States)

Gyuranecz, Miklós

2015-01-01

OBJECTIVES: Earthquakes are one the most common natural disasters that lead to increased mortality and morbidity from transmissible diseases, partially because the rodents displaced by an earthquake can lead to an increased rate of disease transmission. The aim of this study was to evaluate the prevalence of plague and tularemia in rodents in the earthquake zones in southeastern Iran. METHODS: In April 2013, a research team was dispatched to explore the possible presence of diseases in rodents displaced by a recent earthquake magnitude 7.7 around the cities of Khash and Saravan in Sistan and Baluchestan Province. Rodents were trapped near and in the earthquake zone, in a location where an outbreak of tularemia was reported in 2007. Rodent serums were tested for a serological survey using an enzyme-linked immunosorbent assay. RESULTS: In the 13 areas that were studied, nine rodents were caught over a total of 200 trap-days. Forty-eight fleas and 10 ticks were obtained from the rodents. The ticks were from the Hyalomma genus and the fleas were from the Xenopsylla genus. All the trapped rodents were Tatera indica. Serological results were negative for plague, but the serum agglutination test was positive for tularemia in one of the rodents. Tatera indica has never been previously documented to be involved in the transmission of tularemia. CONCLUSIONS: No evidence of the plague cycle was found in the rodents of the area, but evidence was found of tularemia infection in rodents, as demonstrated by a positive serological test for tularemia in one rodent. PMID:26602769

Slow waves, sharp waves, ripples, and REM in sleeping dragons.

Science.gov (United States)

Shein-Idelson, Mark; Ondracek, Janie M; Liaw, Hua-Peng; Reiter, Sam; Laurent, Gilles

2016-04-29

Sleep has been described in animals ranging from worms to humans. Yet the electrophysiological characteristics of brain sleep, such as slow-wave (SW) and rapid eye movement (REM) activities, are thought to be restricted to mammals and birds. Recording from the brain of a lizard, the Australian dragon Pogona vitticeps, we identified SW and REM sleep patterns, thus pushing back the probable evolution of these dynamics at least to the emergence of amniotes. The SW and REM sleep patterns that we observed in lizards oscillated continuously for 6 to 10 hours with a period of ~80 seconds. The networks controlling SW-REM antagonism in amniotes may thus originate from a common, ancient oscillator circuit. Lizard SW dynamics closely resemble those observed in rodent hippocampal CA1, yet they originate from a brain area, the dorsal ventricular ridge, that has no obvious hodological similarity with the mammalian hippocampus. Copyright © 2016, American Association for the Advancement of Science.

Compositional and expression analyses of the glideosome during the Plasmodium life cycle reveal an additional myosin light chain required for maximum motility.

Science.gov (United States)

Green, Judith L; Wall, Richard J; Vahokoski, Juha; Yusuf, Noor A; Ridzuan, Mohd A Mohd; Stanway, Rebecca R; Stock, Jessica; Knuepfer, Ellen; Brady, Declan; Martin, Stephen R; Howell, Steven A; Pires, Isa P; Moon, Robert W; Molloy, Justin E; Kursula, Inari; Tewari, Rita; Holder, Anthony A

2017-10-27

Myosin A (MyoA) is a Class XIV myosin implicated in gliding motility and host cell and tissue invasion by malaria parasites. MyoA is part of a membrane-associated protein complex called the glideosome, which is essential for parasite motility and includes the MyoA light chain myosin tail domain-interacting protein (MTIP) and several glideosome-associated proteins (GAPs). However, most studies of MyoA have focused on single stages of the parasite life cycle. We examined MyoA expression throughout the Plasmodium berghei life cycle in both mammalian and insect hosts. In extracellular ookinetes, sporozoites, and merozoites, MyoA was located at the parasite periphery. In the sexual stages, zygote formation and initial ookinete differentiation precede MyoA synthesis and deposition, which occurred only in the developing protuberance. In developing intracellular asexual blood stages, MyoA was synthesized in mature schizonts and was located at the periphery of segmenting merozoites, where it remained throughout maturation, merozoite egress, and host cell invasion. Besides the known GAPs in the malaria parasite, the complex included GAP40, an additional myosin light chain designated essential light chain (ELC), and several other candidate components. This ELC bound the MyoA neck region adjacent to the MTIP-binding site, and both myosin light chains co-located to the glideosome. Co-expression of MyoA with its two light chains revealed that the presence of both light chains enhances MyoA-dependent actin motility. In conclusion, we have established a system to study the interplay and function of the three glideosome components, enabling the assessment of inhibitors that target this motor complex to block host cell invasion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Comparative genomic analysis of the arthropod muscle myosin heavy chain genes allows ancestral gene reconstruction and reveals a new type of 'partially' processed pseudogene

Directory of Open Access Journals (Sweden)

Kollmar Martin

2008-02-01

Full Text Available Abstract Background Alternative splicing of mutually exclusive exons is an important mechanism for increasing protein diversity in eukaryotes. The insect Mhc (myosin heavy chain gene produces all different muscle myosins as a result of alternative splicing in contrast to most other organisms of the Metazoa lineage, that have a family of muscle genes with each gene coding for a protein specialized for a functional niche. Results The muscle myosin heavy chain genes of 22 species of the Arthropoda ranging from the waterflea to wasp and Drosophila have been annotated. The analysis of the gene structures allowed the reconstruction of an ancient muscle myosin heavy chain gene and showed that during evolution of the arthropods introns have mainly been lost in these genes although intron gain might have happened in a few cases. Surprisingly, the genome of Aedes aegypti contains another and that of Culex pipiens quinquefasciatus two further muscle myosin heavy chain genes, called Mhc3 and Mhc4, that contain only one variant of the corresponding alternative exons of the Mhc1 gene. Mhc3 transcription in Aedes aegypti is documented by EST data. Mhc3 and Mhc4 inserted in the Aedes and Culex genomes either by gene duplication followed by the loss of all but one variant of the alternative exons, or by incorporation of a transcript of which all other variants have been spliced out retaining the exon-intron structure. The second and more likely possibility represents a new type of a 'partially' processed pseudogene. Conclusion Based on the comparative genomic analysis of the alternatively spliced arthropod muscle myosin heavy chain genes we propose that the splicing process operates sequentially on the transcript. The process consists of the splicing of the mutually exclusive exons until one exon out of the cluster remains while retaining surrounding intronic sequence. In a second step splicing of introns takes place. A related mechanism could be responsible for

The bioeconomics of controlling an African rodent pest species

DEFF Research Database (Denmark)

Skonhoft, Anders; Leirs, Herwig; Andreassen, Harry P

2006-01-01

The paper treats the economy of controlling an African pest rodent, the multimammate rat, causing major damage in maize production. An ecological population model is presented and used as a basis for the economic analyses carried out at the village level using data from Tanzania. This model...... incorporates both density-dependent and density-independent (stochastic) factors. Rodents are controlled by applying poison, and the costs are made up of the cost of poison plus the damage to maize production. We analyse how the present-value costs of maize production are affected by various rodent control...

Finding the Cell Center by a Balance of Dynein and Myosin Pulling and Microtubule Pushing: A Computational Study

Science.gov (United States)

Zhu, Jie; Burakov, Anton; Rodionov, Vladimir

2010-01-01

The centrosome position in many types of interphase cells is actively maintained in the cell center. Our previous work indicated that the centrosome is kept at the center by pulling force generated by dynein and actin flow produced by myosin contraction and that an unidentified factor that depends on microtubule dynamics destabilizes position of the centrosome. Here, we use modeling to simulate the centrosome positioning based on the idea that the balance of three forces—dyneins pulling along microtubule length, myosin-powered centripetal drag, and microtubules pushing on organelles—is responsible for the centrosome displacement. By comparing numerical predictions with centrosome behavior in wild-type and perturbed interphase cells, we rule out several plausible hypotheses about the nature of the microtubule-based force. We conclude that strong dynein- and weaker myosin-generated forces pull the microtubules inward competing with microtubule plus-ends pushing the microtubule aster outward and that the balance of these forces positions the centrosome at the cell center. The model also predicts that kinesin action could be another outward-pushing force. Simulations demonstrate that the force-balance centering mechanism is robust yet versatile. We use the experimental observations to reverse engineer the characteristic forces and centrosome mobility. PMID:20980619

Myosin light chain kinase knockout improves gut barrier function and confers a survival advantage in polymicrobial sepsis.

Science.gov (United States)

Lorentz, C Adam; Liang, Zhe; Meng, Mei; Chen, Ching-Wen; Yoseph, Benyam P; Breed, Elise R; Mittal, Rohit; Klingensmith, Nathan J; Farris, Alton B; Burd, Eileen M; Koval, Michael; Ford, Mandy L; Coopersmith, Craig M

2017-06-07

Sepsis-induced intestinal hyperpermeability is mediated by disruption of the epithelial tight junction, which is closely associated with the peri-junctional actin-myosin ring. Myosin light chain kinase (MLCK) phosphorylates the myosin regulatory light chain, resulting in increased permeability. The purpose of this study was to determine whether genetic deletion of MLCK would alter gut barrier function and survival from sepsis. MLCK -/- and wild type (WT) mice were subjected to cecal ligation and puncture and assayed for both survival and mechanistic studies. Survival was significantly increased in MLCK -/- mice (95% vs. 24%, p<0.0001). Intestinal permeability increased in septic WT mice compared to unmanipulated mice. In contrast, permeability in septic MLCK -/- mice was similar to that seen in unmanipulated animals. Improved gut barrier function in MLCK -/- mice was associated with increases in the tight junction mediators ZO-1 and claudin 15 without alterations in claudin 1, 2, 3, 4, 5, 7, 8, 13, occludin or JAM-A. Other components of intestinal integrity (apoptosis, proliferation and villus length) were unaffected by MLCK deletion as were local peritoneal inflammation and distant lung injury. Systemic IL-10 was decreased greater than 10-fold in MLCK -/- mice; however, survival was similar between septic MLCK -/- mice given exogenous IL-10 or vehicle. These data demonstrate that deletion of MLCK improves survival following sepsis, associated with normalization of intestinal permeability and selected tight junction proteins.

Determining the impact of oxidation on the motility of single muscle-fibres expressing different myosin isoforms

DEFF Research Database (Denmark)

Spanos, Dimitrios; Li, M.; Baron, Caroline P.

2013-01-01

heavy chain (MyHC) isoforms has not been previously investigated. Oxidation of myosin isolated from muscle fibres originating from various porcine muscles with a different metabolic profile was studied using a single muscle fibre in-vitro motility assay, allowing measurements of catalytic properties...... (motility speed) and force-generation capacity of specific MyHC isoforms. In the experimental procedure, single muscle fibres were split in different segments and each segment was exposed to a different concentration of hydrogen peroxide. Speed and force measurements were recorded and compared, to assess...... the effect of myosin oxidation on motility and force. The MyHC isoform expression in the single muscle fibre was subsequently determined on silver-stained gel SDS-PAGE. Preliminary results indicate a decrease of directionality and speed of the in-vitro motility as a result of an oxidative environment...

Positron imaging feasibility studies: characteristics of 2-deoxyglucose uptake in rodent and canine neoplasms

International Nuclear Information System (INIS)

Larson, S.M.; Weiden, P.L.; Grunbaum, J.

1981-01-01

Uptake of [ 3 H]2-deoxyglucose was studied in BALB/c mice with EMT-6 sarcoma, in Buffalo rats with Morris 7777 hepatoma, and in eight dogs with spontaneous neoplasms: five osteosarcomas and three diffuse lymphomas. High tumor-to-tissue ratios were observed for all tumor types studies. In rodents, peak levels of uptake occurred between 30 min and 1 hr, with a slow loss from the tumor of about 10% per hour thereafter. In dogs there was considerable variability in uptake, both between individuals and at different tumor sites within an individual. Necrotic tumor did not take up the radiotracer. Absolute uptakes, when normalized for body weight, were similar for spontaneous and transplanted neoplasms. These studies provide additional support for the concept that positron emission tomography can be used to obtain functional images of important metabolic processes of tumors, including glycolysis

Association of Myosin Va and Schwann cells-derived RNA in mammal myelinated axons, analyzed by immunocytochemistry and confocal FRET microscopy.

Science.gov (United States)

Canclini, Lucía; Wallrabe, Horst; Di Paolo, Andrés; Kun, Alejandra; Calliari, Aldo; Sotelo-Silveira, José Roberto; Sotelo, José Roberto

2014-03-15

Evidence from multiple sources supports the hypothesis that Schwann cells in the peripheral nervous system transfer messenger RNA and ribosomes to the axons they ensheath. Several technical and methodological difficulties exist for investigators to unravel this process in myelinated axons - a complex two-cell unit. We present an experimental design to demonstrate that newly synthesized RNA is transferred from Schwann cells to axons in association with Myosin Va. The use of quantitative confocal FRET microscopy to track newly-synthesized RNA and determine the molecular association with Myosin Va, is described in detail. Copyright © 2013 Elsevier Inc. All rights reserved.

Semi-Autonomous Rodent Habitat for Deep Space Exploration

Science.gov (United States)

Alwood, J. S.; Shirazi-Fard, Y.; Pletcher, D.; Globus, R.

2018-01-01

NASA has flown animals to space as part of trailblazing missions and to understand the biological responses to spaceflight. Mice traveled in the Lunar Module with the Apollo 17 astronauts and now mice are frequent research subjects in LEO on the ISS. The ISS rodent missions have focused on unravelling biological mechanisms, better understanding risks to astronaut health, and testing candidate countermeasures. A critical barrier for longer-duration animal missions is the need for humans-in-the-loop to perform animal husbandry and perform routine tasks during a mission. Using autonomous or telerobotic systems to alleviate some of these tasks would enable longer-duration missions to be performed at the Deep Space Gateway. Rodent missions performed using the Gateway as a platform could address a number of critical risks identified by the Human Research Program (HRP), as well as Space Biology Program questions identified by NRC Decadal Survey on Biological and Physical Sciences in Space, (2011). HRP risk areas of potentially greatest relevance that the Gateway rodent missions can address include those related to visual impairment (VIIP) and radiation risks to central nervous system, cardiovascular disease, as well as countermeasure testing. Space Biology focus areas addressed by the Gateway rodent missions include mechanisms and combinatorial effects of microgravity and radiation. The objectives of the work proposed here are to 1) develop capability for semi-autonomous rodent research in cis-lunar orbit, 2) conduct key experiments for testing countermeasures against low gravity and space radiation. The hardware and operations system developed will enable experiments at least one month in duration, which potentially could be extended to one year in duration. To gain novel insights into the health risks to crew of deep space travel (i.e., exposure to space radiation), results obtained from Gateway flight rodents can be compared to ground control groups and separate groups

Study of hantavirus infection in captive breed colonies of wild rodents

Directory of Open Access Journals (Sweden)

RC Oliveira

2004-10-01

Full Text Available Wild sigmondontine rodents are known to be the reservoir of several serotypes of New World hantaviruses. The mechanism of viral transmission is by aerosol inhalation of the excreta from infected rodents. Considering that the captive breed colonies of various wild mammals may present a potencial risk for hantaviral transmission, we examined 85 speciemens of Thrichomys spp. (Echimyidae and 17 speciemens of Nectomys squamipes (Sigmodontinae from our colony for the presence of hantavirus infections. Blood samples were assayed for the presence of antibodies to Andes nucleocapsid antigen using enzyme-linked immunosorbent assay (ELISA. Additionally, serum samples from workers previously exposed to wild rodents, in the laboratories where the study was conducted, were also tested by ELISA to investigate prevalence of anti-hantavirus IgG antibodies. All blood samples were negative for hantavirus antibodies. Although these results suggest that those rodent's colonies are hantavirus free, the work emphasizes the need for hantavirus serological monitoring in wild colonized rodents and secure handling potentially infected rodents as important biosafety measures.

Thieving rodents as substitute dispersers of megafaunal seeds

Science.gov (United States)

Jansen, Patrick A.; Hirsch, Ben T.; Emsens, Willem-Jan; Zamora-Gutierrez, Veronica; Wikelski, Martin; Kays, Roland

2012-01-01

The Neotropics have many plant species that seem to be adapted for seed dispersal by megafauna that went extinct in the late Pleistocene. Given the crucial importance of seed dispersal for plant persistence, it remains a mystery how these plants have survived more than 10,000 y without their mutualist dispersers. Here we present support for the hypothesis that secondary seed dispersal by scatter-hoarding rodents has facilitated the persistence of these large-seeded species. We used miniature radio transmitters to track the dispersal of reputedly megafaunal seeds by Central American agoutis, which scatter-hoard seeds in shallow caches in the soil throughout the forest. We found that seeds were initially cached at mostly short distances and then quickly dug up again. However, rather than eating the recovered seeds, agoutis continued to move and recache the seeds, up to 36 times. Agoutis dispersed an estimated 35% of seeds for >100 m. An estimated 14% of the cached seeds survived to the next year, when a new fruit crop became available to the rodents. Serial video-monitoring of cached seeds revealed that the stepwise dispersal was caused by agoutis repeatedly stealing and recaching each other’s buried seeds. Although previous studies suggest that rodents are poor dispersers, we demonstrate that communities of rodents can in fact provide highly effective long-distance seed dispersal. Our findings suggest that thieving scatter-hoarding rodents could substitute for extinct megafaunal seed dispersers of tropical large-seeded trees. PMID:22802644

/sup 99m/Tc labeling of antibodies to cardiac myosin Fab and to human fibrinogen

International Nuclear Information System (INIS)

Khaw, B.A.; Strauss, H.W.; Carvalho, A.; Locke, E.; Gold, H.K.; Haber, E.

1982-01-01

We have developed a method of labeling biologically active labile macromolecules, such as human fibrinogen (HF) and anticardiac-myosin Fab (AM-Fab), with /sup 99m/Tc at neutral pH. This method uses dithionite reduction of pertechnetate and subsequent labeling, to test the method with acid-labile macromolecules. Complexes of diethylene triamine pentaacetic acid with macromolecules such as human fibrinogen (D-HF) and anticardiac-myosin Fab (D-AM-Fab) were labeled and utilized in in vitro and in vivo studies. In biodistribution studies, the /sup 99m/Tc D-HF had a two-component blood clearance (half-times 1 hr and 15 hr) and was 80--88% coagulable. The /sup 99m/Tc AM-Fab retained its immunoreactivity as tested by affinity chromatography; also during in vivo localization in experimental myocardial infarction. This labeling technique provides an easy and efficient approach to the /sup 99m/Tc labeling of other biologically active and acid-labile macromolecules

SNPs within the beta myosin heavy chain (MYH7 and the pyruvate kinase muscle (PKM2 genes in horse

Directory of Open Access Journals (Sweden)

Vincenzo Russo

2010-01-01

Full Text Available Two highly expressed skeletal muscle genes (the MYH7 gene encoding the myosin heavy chain slow/β-cardiac isoform and the PKM2 gene encoding the pyruvate kinase muscle isoforms were investigated with the objective to identify DNA markers in horses. A panel of DNA samples from different horse breeds was analysed using a PCR-single strand conformation polymorphism (SSCP approach. Four and two alleles were identified for the MYH7 and PKM2 loci, respectively. Mendelian inheritance of alleles of the two investigated genes was confirmed analysing horse families. Sequencing of PCR products obtained from the MYH7 and PKM2 genes made it possible to characterise two SSCP alleles for each gene. The polymorphisms found in the MYH7 and PKM2 genes were further studied in 61 and 68 horses of three (Italian Heavy Draught Horse, Italian Saddler and Murgese and five (Franches-Montagnes, Haflinger, Italian Heavy Draught Horse, Murgese and Standardbred breeds, respectively. Allele frequencies of the two loci varied among the considered breeds. The SNPs discovery in MYH7 and PKM2 genes makes it possible to locate new molecular markers to ECA1. The identified markers could be used in association analysis with performance traits in horses.

The role of rodents in avian influenza outbreaks in poultry farms: a review.

Science.gov (United States)

Velkers, Francisca C; Blokhuis, Simon J; Veldhuis Kroeze, Edwin J B; Burt, Sara A

2017-12-01

Wild migratory birds are associated with global avian influenza virus (AIV) spread. Although direct contact with wild birds and contaminated fomites is unlikely in modern non-free range poultry farms applying biosecurity measures, AIV outbreaks still occur. This suggests involvement of other intermediate factors for virus transmission between wild birds and poultry. This review describes current evidence of the potential role of rodents in AIV transmission from wild birds to poultry and between poultry houses. Rodents can be abundant around poultry houses, share their habitat with waterfowl and can readily enter poultry houses. Survival of AIV from waterfowl in poultry house surroundings and on the coat of rodents suggests that rodents are likely to act as mechanical vector. AIVs can replicate in rodents without adaptation, resulting in high viral titres in lungs and nasal turbinates, virus presence in nasal washes and saliva, and transmission to naïve contact animals. Therefore, active AIV shedding by infected rodents may play a role in transmission to poultry. Further field and experimental studies are needed to provide evidence for a role of rodents in AIV epidemiology. Making poultry houses rodent-proof and the immediate surroundings unattractive for rodents are recommended as preventive measures against possible AIV introduction.

Human myosin VIIA responsible for the Usher 1B syndrome: a predicted membrane-associated motor protein expressed in developing sensory epithelia.

Science.gov (United States)

Weil, D; Levy, G; Sahly, I; Levi-Acobas, F; Blanchard, S; El-Amraoui, A; Crozet, F; Philippe, H; Abitbol, M; Petit, C

1996-04-16

The gene encoding human myosin VIIA is responsible for Usher syndrome type III (USH1B), a disease which associates profound congenital sensorineural deafness, vestibular dysfunction, and retinitis pigmentosa. The reconstituted cDNA sequence presented here predicts a 2215 amino acid protein with a typical unconventional myosin structure. This protein is expected to dimerize into a two-headed molecule. The C terminus of its tail shares homology with the membrane-binding domain of the band 4.1 protein superfamily. The gene consists of 48 coding exons. It encodes several alternatively spliced forms. In situ hybridization analysis in human embryos demonstrates that the myosin VIIA gene is expressed in the pigment epithelium and the photoreceptor cells of the retina, thus indicating that both cell types may be involved in the USH1B retinal degenerative process. In addition, the gene is expressed in the human embryonic cochlear and vestibular neuroepithelia. We suggest that deafness and vestibular dysfunction in USH1B patients result from a defect in the morphogenesis of the inner ear sensory cell stereocilia.

Towards sustainable management of rodents in organic animal husbandry

NARCIS (Netherlands)

Meerburg, B.G.; Bonde, M.; Brom, F.W.A.; Endepols, S.; Jensen, A.N.; Leirs, H.; Lodal, J.; Singleton, G.R.; Pelz, H.J.; Rodenburg, T.B.; Kijlstra, A.

2004-01-01

From 26 to 28 May 2004 an international seminar was held in Wageningen, the Netherlands, about current knowledge and advice on rodent management on organic pig and poultry farms in Western Europe. This paper summarizes the discussions. Rodent management is necessary to protect the food production

Nonmuscle myosin IIB as a therapeutic target for the prevention of relapse to methamphetamine use

Science.gov (United States)

Young, Erica J.; Blouin, Ashley M.; Briggs, Sherri B.; Sillivan, Stephanie E.; Lin, Li; Cameron, Michael D.; Rumbaugh, Gavin; Miller, Courtney A.

2015-01-01

Memories associated with drug use increase vulnerability to relapse in substance use disorder (SUD) and there are no pharmacotherapies for the prevention of relapse. Previously, we reported a promising finding that storage of memories associated with methamphetamine (METH), but not memories for fear or food reward, is vulnerable to disruption by actin depolymerization in the basolateral amygdala complex (BLC). However, actin is not a viable therapeutic target because of its numerous functions throughout the body. Here we report the discovery of a viable therapeutic target, nonmuscle myosin II (NMIIB), a molecular motor that supports memory by directly driving synaptic actin polymerization. A single intra-BLC treatment with Blebbistatin, a small molecule inhibitor of class II myosin isoforms, including NMIIB, produced a long-lasting disruption of context-induced drug seeking (at least 30 days). Further, post-consolidation genetic knockdown of Myh10, the heavy chain of the most highly expressed NMII in the BLC, was sufficient to produce METH-associated memory loss. Blebbistatin was found to be highly brain penetrant. A single systemic injection of the compound selectively disrupted the storage of METH-associated memory and reversed the accompanying increase in BLC spine density. This effect was specific to METH-associated memory, as it had no effect on an auditory fear memory. The effect was also independent of retrieval, as METH-associated memory was disrupted twenty-four hours after a single systemic injection of Blebbistatin delivered in the home cage. Together, these results argue for the further development of small molecule inhibitors of nonmuscle myosin II as potential therapeutics for the prevention of SUD relapse triggered by drug associations. PMID:26239291

Rigor force responses of permeabilized fibres from fast and slow skeletal muscles of aged rats.

Science.gov (United States)

Plant, D R; Lynch, G S

2001-09-01

1. Ageing is generally associated with a decline in skeletal muscle mass and strength and a slowing of muscle contraction, factors that impact upon the quality of life for the elderly. The mechanisms underlying this age-related muscle weakness have not been fully resolved. The purpose of the present study was to determine whether the decrease in muscle force as a consequence of age could be attributed partly to a decrease in the number of cross-bridges participating during contraction. 2. Given that the rigor force is proportional to the approximate total number of interacting sites between the actin and myosin filaments, we tested the null hypothesis that the rigor force of permeabilized muscle fibres from young and old rats would not be different. 3. Permeabilized fibres from the extensor digitorum longus (fast-twitch; EDL) and soleus (predominantly slow-twitch) muscles of young (6 months of age) and old (27 months of age) male F344 rats were activated in Ca2+-buffered solutions to determine force-pCa characteristics (where pCa = -log(10)[Ca2+]) and then in solutions lacking ATP and Ca2+ to determine rigor force levels. 4. The rigor forces for EDL and soleus muscle fibres were not different between young and old rats, indicating that the approximate total number of cross-bridges that can be formed between filaments did not decline with age. We conclude that the age-related decrease in force output is more likely attributed to a decrease in the force per cross-bridge and/or decreases in the efficiency of excitation-contraction coupling.

Population dynamics of Rodents and Insectivores in lowland tropical ...

African Journals Online (AJOL)

The community structure of rodents and insectivores in the lowland tropical rainforest of Okomu National Park, Edo State, Nigeria was assessed using a combination of live-trapping and sighting techniques during the dry and wet seasons. Seventeen species (14 species of rodent, 3 species of insectivores) were captured, ...

Multiple infections of rodents with zoonotic pathogens in Austria.

Science.gov (United States)

Schmidt, Sabrina; Essbauer, Sandra S; Mayer-Scholl, Anne; Poppert, Sven; Schmidt-Chanasit, Jonas; Klempa, Boris; Henning, Klaus; Schares, Gereon; Groschup, Martin H; Spitzenberger, Friederike; Richter, Dania; Heckel, Gerald; Ulrich, Rainer G

2014-07-01

Rodents are important reservoirs for a large number of zoonotic pathogens. We examined the occurrence of 11 viral, bacterial, and parasitic agents in rodent populations in Austria, including three different hantaviruses, lymphocytic choriomeningitis virus, orthopox virus, Leptospira spp., Borrelia spp., Rickettsia spp., Bartonella spp., Coxiella burnetii, and Toxoplasma gondii. In 2008, 110 rodents of four species (40 Clethrionomys glareolus, 29 Apodemus flavicollis, 26 Apodemus sylvaticus, and 15 Microtus arvalis) were trapped at two rural sites in Lower Austria. Chest cavity fluid and samples of lung, spleen, kidney, liver, brain, and ear pinna skin were collected. We screened selected tissue samples for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, Leptospira, Borrelia, Rickettsia, Bartonella spp., C. burnetii, and T. gondii by RT-PCR/PCR and detected nucleic acids of Tula hantavirus, Leptospira spp., Borrelia afzelii, Rickettsia spp., and different Bartonella species. Serological investigations were performed for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, and Rickettsia spp. Here, Dobrava-Belgrade hantavirus-, Tula hantavirus-, lymphocytic choriomeningitis virus-, orthopox virus-, and rickettsia-specific antibodies were demonstrated. Puumala hantavirus, C. burnetii, and T. gondii were neither detected by RT-PCR/PCR nor by serological methods. In addition, multiple infections with up to three pathogens were shown in nine animals of three rodent species from different trapping sites. In conclusion, these results show that rodents in Austria may host multiple zoonotic pathogens. Our observation raises important questions regarding the interactions of different pathogens in the host, the countermeasures of the host's immune system, the impact of the host-pathogen interaction on the fitness of the host, and the spread of infectious agents among wild rodents and from those to other animals or humans.

Revealing the cluster of slow transients behind a large slow slip event.

Science.gov (United States)

Frank, William B; Rousset, Baptiste; Lasserre, Cécile; Campillo, Michel

2018-05-01

Capable of reaching similar magnitudes to large megathrust earthquakes [ M w (moment magnitude) > 7], slow slip events play a major role in accommodating tectonic motion on plate boundaries through predominantly aseismic rupture. We demonstrate here that large slow slip events are a cluster of short-duration slow transients. Using a dense catalog of low-frequency earthquakes as a guide, we investigate the M w 7.5 slow slip event that occurred in 2006 along the subduction interface 40 km beneath Guerrero, Mexico. We show that while the long-period surface displacement, as recorded by Global Positioning System, suggests a 6-month duration, the motion in the direction of tectonic release only sporadically occurs over 55 days, and its surface signature is attenuated by rapid relocking of the plate interface. Our proposed description of slow slip as a cluster of slow transients forces us to re-evaluate our understanding of the physics and scaling of slow earthquakes.

Farmer survey in the hinterland of Kisangani (Democratic Republic of Congo) on rodent crop damage and rodent control techniques used

DEFF Research Database (Denmark)

Drazo, Nicaise Amundala; Kennis, Jan; Leirs, Herwig

2008-01-01

We conducted a survey on rodent crop damage among farmers in the hinterland of Kisangani (Democratic Republic of Congo). We studied the amount of crop damage, the rodent groups causing crop damage, the growth stages affected and the control techniques used. We conducted this survey in three...... municipalities using a standard questionnaire form translated into local languages, between November 2005 and June 2006 and during July 2007. We used the Quotas method and interviewed 70 households per municipality. Farmers indicated rodent groups implicated in crop damage on color photographs. Two types...... of survey techniques were used: individual and focus-group surveys. The sugar cane rat, Thryonomys sp. and Lemniscomys striatus caused most damage to crops, but inside granaries, Rattus rattus was the primary pest species eating stored food supplies and causing damage to stored goods. Cassava and maize were...

Altered fast- and slow-twitch muscle fibre characteristics in female mice with a (S248F) knock-in mutation of the brain neuronal nicotinic acetylcholine receptor.

Science.gov (United States)

Cannata, David J; Finkelstein, David I; Gantois, Ilse; Teper, Yaroslav; Drago, John; West, Jan M

2009-01-01

We generated a mouse line with a missense mutation (S248F) in the gene (CHRNA4) encoding the alpha4 subunit of neuronal nicotinic acetylcholine receptor (nAChR). Mutant mice demonstrate brief nicotine induced dystonia that resembles the clinical events seen in patients with the same mutation. Drug-induced dystonia is more pronounced in female mice, thus our aim was to determine if the S248F mutation changed the properties of fast- and slow-twitch muscle fibres from female mutant mice. Reverse transcriptase-PCR confirmed CHRNA4 gene expression in the brain but not skeletal muscles in normal and mutant mice. Ca(2+) and Sr(2+) force activation curves were obtained using skinned muscle fibres prepared from slow-twitch (soleus) and fast-twitch (EDL) muscles. Two significant results were found: (1) the (pCa(50) - pSr(50)) value from EDL fibres was smaller in mutant mice than in wild type (1.01 vs. 1.30), (2) the percentage force produced at pSr 5.5 was larger in mutants than in wild type (5.76 vs. 0.24%). Both results indicate a shift to slow-twitch characteristics in the mutant. This conclusion is supported by the identification of the myosin heavy chain (MHC) isoforms. Mutant EDL fibres expressed MHC I (usually only found in slow-twitch fibres) as well as MHC IIa. Despite the lack of spontaneous dystonic events, our findings suggest that mutant mice may be having subclinical events or the mutation results in a chronic alteration to muscle neural input.

Age- and Activity-Related Differences in the Abundance of Myosin Essential and Regulatory Light Chains in Human Muscle

Directory of Open Access Journals (Sweden)

James N. Cobley

2016-04-01

Full Text Available Traditional methods for phenotyping skeletal muscle (e.g., immunohistochemistry are labor-intensive and ill-suited to multixplex analysis, i.e., assays must be performed in a series. Addressing these concerns represents a largely unmet research need but more comprehensive parallel analysis of myofibrillar proteins could advance knowledge regarding age- and activity-dependent changes in human muscle. We report a label-free, semi-automated and time efficient LC-MS proteomic workflow for phenotyping the myofibrillar proteome. Application of this workflow in old and young as well as trained and untrained human skeletal muscle yielded several novel observations that were subsequently verified by multiple reaction monitoring (MRM. We report novel data demonstrating that human ageing is associated with lesser myosin light chain 1 content and greater myosin light chain 3 content, consistent with an age-related reduction in type II muscle fibers. We also disambiguate conflicting data regarding myosin regulatory light chain, revealing that age-related changes in this protein more closely reflect physical activity status than ageing per se. This finding reinforces the need to control for physical activity levels when investigating the natural process of ageing. Taken together, our data confirm and extend knowledge regarding age- and activity-related phenotypes. In addition, the MRM transitions described here provide a methodological platform that can be fine-tuned to suite multiple research needs and thus advance myofibrillar phenotyping.

MR microscopy of the lung in small rodents

International Nuclear Information System (INIS)

Takahashi, Masaya; Kubo, Shigeto; Kiryu, Shigeru; Gee, James; Hatabu, Hiroto

2007-01-01

Understanding how the mammalian respiratory system works and how it changes in disease states and under the influence of drugs is frequently pursued in model systems such as small rodents. These have many advantages, including being easily obtained in large numbers as purebred strains. Studies in small rodents are valuable for proof of concept studies and for increasing our knowledge about disease mechanisms. Since the recent developments in the generation of genetically designed animal models of disease, one needs the ability to assess morphology and function in in vivo systems. In this article, we first review previous reports regarding thoracic imaging. We then discuss approaches to take in making use of small rodents to increase MR microscopic sensitivity for these studies and to establish MR methods for clinically relevant lung imaging

Ecology of rodents at an old quarry in Zambia

African Journals Online (AJOL)

Ecology of rodents at an old quarry in Zambia. E.N. Chidumayo. Livingstone Museum, Zambia. An old quarry, 2,5 hain size near Livingstone in southern. Zambia was kill- and live-trapped between September 1974 and December 1976 to determine ecological relations among. rodent species inhabiting it. Seven species ...

Time course of myosin heavy chain transitions in neonatal rats: importance of innervation and thyroid state

Science.gov (United States)

Adams, G. R.; McCue, S. A.; Zeng, M.; Baldwin, K. M.

1999-01-01

During the postnatal period, rat limb muscles adapt to weight bearing via the replacement of embryonic (Emb) and neonatal (Neo) myosin heavy chains (MHCs) by the adult isoforms. Our aim was to characterize this transition in terms of the six MHC isoforms expressed in skeletal muscle and to determine the importance of innervation and thyroid hormone status on the attainment of the adult MHC phenotype. Neonatal rats were made hypothyroid via propylthiouracil (PTU) injection. In normal and PTU subgroups, leg muscles were unilaterally denervated at 15 days of age. The MHC profiles of plantaris (PLN) and soleus (Sol) muscles were determined at 7, 14, 23, and 30 days postpartum. At day 7, the Sol MHC profile was 55% type I, 30% Emb, and 10% Neo; in the PLN, the pattern was 60% Neo and 25% Emb. By day 30 the Sol and PLN had essentially attained an adult MHC profile in the controls. PTU augmented slow MHC expression in the Sol, whereas in the PLN it markedly repressed IIb MHC by retaining neonatal MHC expression. Denervation blunted the upregulation of IIb in the PLN and of Type I in the Sol and shifted the pattern to greater expression of IIa and IIx MHCs in both muscles. In contrast to previous observations, these findings collectively suggest that both an intact thyroid and innervation state are obligatory for the attainment of the adult MHC phenotype, particularly in fast-twitch muscles.

Cell differentiation through tissue elasticity-coupled, myosin-driven remodeling.

Science.gov (United States)

Zajac, Allison L; Discher, Dennis E

2008-12-01

Cells may lack eyes to see and ears to hear, but cells do seem to have a sense of 'touch' that allows them to feel their microenvironment. This is achieved in part through contractility coupled adhesion to physically flexible 'soft' tissue. Here we summarize some of the known variations in elasticity of solid tissue and review some of the long-term effects of cells 'feeling' this elasticity, focusing on differentiation processes of both committed cell types and stem cells. We then highlight what is known of molecular remodeling in cells under stress on short time scales. Key roles for forces generated by ubiquitous and essential myosin-II motors in feedback remodeling are emphasized throughout.

Natural Intestinal Protozoa in Rodents (Rodentia: Gerbillinae, Murinae, Cricetinae in Northwestern Iran

Directory of Open Access Journals (Sweden)

Mehdi MOHEBALI

2017-09-01

Full Text Available Background: Majority of parasitic infections in rodents have zoonotic importance. This study aimed to determine the frequency and intensity of intestinal protozoa infections of rodents including Meriones persicus, Mus musculus and, Cricetulus migratorius.Methods: This survey was conducted in Meshkin Shahr district in northwestern Iran from Mar. to Dec. of 2014. Intestinal samples of 204 rodents including M. persicus (n=117, M. musculus (n=63 and C. migratorius (n=24 were parasitologically examined. Formalin-ether concentration method was done for all of rodents stool samples and observed with light microscope. All of suspected cases were stained with trichorome staining Method. Cultivation in dichromate potassium 2.5% was carried out for all of coccidian positive samples. Acid fast and aniline blue staining methods were used for detecting of coccidian oocysts and intestinal microsporidial spores, respectively.Results: About 121(59.3% of the caught rodents were generally infected with intestinal protozoa. Entamoeba muris 14(6.9%, Trichomonas muris 55(27.0%, Chilomastix betencourtti 17 (8.3%, Giardia muris 19(9.3%, Eimeria spp. 46(22.5%, Isospora spp. 4(2% and Cryptosporidium spp. 1(0.5% were found from the collected rodents. Microsporidian spores were identified in 63 (31% out of the 204 collected rodents using aniline blue staining method.Conclusion: Since some of the infections are zoonotic importance thus, control of rodents can be decreased new cases of the parasitic zoonoses in humans.

Natural Intestinal Protozoa in Rodents (Rodentia: Gerbillinae, Murinae, Cricetinae) in Northwestern Iran

Science.gov (United States)

MOHEBALI, Mehdi; ZAREI, Zabiholah; Khanaliha, Khadijeh; KIA, Eshrat Beigom; MOTAVALLI-HAGHI, Afsaneh; DAVOODI, Jaber; REZAEIAN, Tahereh; TARIGHI, Fathemeh; REZAEIAN, Mostafa

2017-01-01

Background: Majority of parasitic infections in rodents have zoonotic importance. This study aimed to determine the frequency and intensity of intestinal protozoa infections of rodents including Meriones persicus, Mus musculus and, Cricetulus migratorius. Methods: This survey was conducted in Meshkin Shahr district in northwestern Iran from Mar. to Dec. of 2014. Intestinal samples of 204 rodents including M. persicus (n=117), M. musculus (n=63) and C. migratorius (n=24) were parasitologically examined. Formalin-ether concentration method was done for all of rodents stool samples and observed with light microscope. All of suspected cases were stained with trichorome staining Method. Cultivation in dichromate potassium 2.5% was carried out for all of coccidian positive samples. Acid fast and aniline blue staining methods were used for detecting of coccidian oocysts and intestinal microsporidial spores, respectively. Results: About 121(59.3%) of the caught rodents were generally infected with intestinal protozoa. Entamoeba muris 14(6.9%), Trichomonas muris 55(27.0%), Chilomastix betencourtti 17 (8.3%), Giardia muris 19(9.3%), Eimeria spp. 46(22.5%), Isospora spp. 4(2%) and Cryptosporidium spp. 1(0.5%) were found from the collected rodents. Microsporidian spores were identified in 63 (31%) out of the 204 collected rodents using aniline blue staining method. Conclusion: Since some of the infections are zoonotic importance thus, control of rodents can be decreased new cases of the parasitic zoonoses in humans. PMID:28979348

Early Eocene rodents (Mammalia) from the Subathu Formation of ...

Indian Academy of Sciences (India)

1997a, b). Most of the rodents from this stratigraphic level have been referred to a rather diverse family Cha- pattimyidae ... Herein we describe a new early Eocene rodent assemblage .... thick zone of brownish red shales that occur as a ..... 1997b;. Plate 3, figure 31). ...... northwestern Pakistan and remarks on the collision.

Research Note. Occurrence of gastrointestinal helminths in commensal rodents from Tabasco, Mexico

Directory of Open Access Journals (Sweden)

Cigarroa-Toledo N.

2017-06-01

Full Text Available The aim of this study was to determine the prevalence and species composition of helminths in commensal rodents captured inside private residences in the city of Villahermosa in Tabasco, Mexico. Trapping was performed at each house for three consecutive nights from October to December 2015. Fifty commensal rodents were captured: 23 Rattus norvegicus, 16 Mus musculus and 11 Rattus rattus. Rodents were transported alive to the laboratory and held in cages until they defecated. Feces were analyzed for helminth eggs using the Sheather’s flotation technique. The overall prevalence of helminths in rodents was 60 %: R. norvegicus was more likely to be parasitized (87.0 % than R. rattus (63.6 % and M. musculus (18.8 %. Eggs from at least 13 species of helminths were identified: Hymenolepis diminuta, Rodentolepis nana, Moniliformis moniliformis, Heligmosomoides polygyrus, Heterakis spumosa, Mastophorus muris, Nippostrongylus brasiliensis, Strongyloides ratti, Syphacia obvelata, Syphacia muris, Toxocara sp., Trichosomoides crassicauda, and Trichuris muris. This is the first study to report the presence of H. polygyrus, S. ratti and T. crassicauda in commensal rodents in Mexico. In conclusion, our results suggest that helminths commonly infect commensal rodents in Villahermosa and therefore rodents present a health risk to inhabitants in this region.

Hypericum perforatum as a cognitive enhancer in rodents: A meta-analysis

Science.gov (United States)

Ben-Eliezer, Daniel; Yechiam, Eldad

2016-01-01

Considered an antidepressant and anti-anxiety agent, Hypericum perforatum affects multiple neurotransmitters in a non-competitive synergistic manner, and may have nootropic potential. We quantitatively reviewed the pre-clinical literature to examine if there is a cognitive-enhancing effect of H. perforatum in healthy rodents. Additionally, within these studies, we compared the effects observed in intact rodents versus those whose performance has been impaired, mostly through stress manipulations. The meta-analysis incorporated studies that examined the effect of H. perforatum versus placebo on memory indices of task performance. All analyses were based on weighting different studies according to their inverse variance. Thirteen independent studies (published 2000–2014) involving 20 experimental comparisons met our inclusion criteria. The results showed a large positive effect of H. perforatum on cognitive performance for intact, healthy rodents (d = 1.11), though a larger effect emerged for stress-impaired rodents (d = 3.10 for restraint stress). The positive effect on intact rodents was observed in tasks assessing reference memory as well as working memory, and was not moderated by the type of memory or motivation (appetitive versus aversive). Thus, while primarily considered as a medication for depression, H. perforatum shows considerable nootropic potential in rodents. PMID:27762349

Neurogenic inflammation in human and rodent skin

DEFF Research Database (Denmark)

Schmelz, M; Petersen, Lars Jelstrup

2001-01-01

The combination of vasodilation and protein extravasation following activation of nociceptors has been termed "neurogenic inflammation." In contrast to rodents, no neurogenic protein extravasation can be elicited in healthy human skin. Dermal microdialysis has considerably increased our knowledge...... about neurogenic inflammation in human skin, including the involvement of mast cells.......The combination of vasodilation and protein extravasation following activation of nociceptors has been termed "neurogenic inflammation." In contrast to rodents, no neurogenic protein extravasation can be elicited in healthy human skin. Dermal microdialysis has considerably increased our knowledge...

Public Health Implications of Changing Rodent Importation Patterns - United States, 1999-2013.

Science.gov (United States)

Lankau, E W; Sinclair, J R; Schroeder, B A; Galland, G G; Marano, N

2017-04-01

The United States imports a large volume of live wild and domestic animal species; these animals pose a demonstrated risk for introduction of zoonotic diseases. Rodents are imported for multiple purposes, including scientific research, zoo exhibits and the pet trade. Current U.S. public health regulatory restrictions specific to rodent importation pertain only to those of African origin. To understand the impacts of these regulations and the potential public health risks of international rodent trade to the United States, we evaluated live rodent import records during 1999-2013 by shipment volume and geographic origin, source (e.g. wild-caught versus captive- or commercially bred), intended purpose and rodent taxonomy. Live rodent imports increased from 2737 animals during 1999 to 173 761 animals during 2013. Increases in both the number and size of shipments contributed to this trend. The proportion of wild-captured imports declined from 75% during 1999 to guinea pigs and hamsters arriving from other countries in North America were predominant taxa underlying this trend. After 2003, African-origin imports became sporadic events under the federal permit process. These patterns suggest development of large-scale captive rodent breeding markets abroad for commercial sale in the United States. While the shift from wild-captured imports alleviates many conservation concerns and risks for novel disease emergence, such consolidated sourcing might elevate exposure risks for zoonotic diseases associated with high-density rodent breeding (e.g. lymphocytic choriomeningitis or salmonellosis). A responsive border health system must periodically re-evaluate importation regulations in conjunction with key stakeholders to ensure a balance between the economic benefits of rodent trade against the potential public health risks. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

The Revised Neurobehavioral Severity Scale (NSS-R) for Rodents.

Science.gov (United States)

Yarnell, Angela M; Barry, Erin S; Mountney, Andrea; Shear, Deborah; Tortella, Frank; Grunberg, Neil E

2016-04-08

Motor and sensory deficits are common following traumatic brain injury (TBI). Although rodent models provide valuable insight into the biological and functional outcomes of TBI, the success of translational research is critically dependent upon proper selection of sensitive, reliable, and reproducible assessments. Published literature includes various observational scales designed to evaluate post-injury functionality; however, the heterogeneity in TBI location, severity, and symptomology can complicate behavioral assessments. The importance of choosing behavioral outcomes that can be reliably and objectively quantified in an efficient manner is becoming increasingly important. The Revised Neurobehavioral Severity Scale (NSS-R) is a continuous series of specific, sensitive, and standardized observational tests that evaluate balance, motor coordination, and sensorimotor reflexes in rodents. The tasks follow a specific order designed to minimize interference: balance, landing, tail raise, dragging, righting reflex, ear reflex, eye reflex, sound reflex, tail pinch, and hindpaw pinch. The NSS-R has proven to be a reliable method differentiating brain-injured rodents from non-brain-injured rodents across many brain injury models. Copyright © 2016 John Wiley & Sons, Inc.

Contractile properties of motor units and expression of myosin heavy chain isoforms in rat fast-type muscle after volitional weight-lifting training.

Science.gov (United States)

Łochyński, Dawid; Kaczmarek, Dominik; Mrówczyński, Włodzimierz; Warchoł, Wojciech; Majerczak, Joanna; Karasiński, Janusz; Korostyński, Michał; Zoladz, Jerzy A; Celichowski, Jan

2016-10-01

Dynamic resistance training increases the force and speed of muscle contraction, but little is known about modifications to the contractile properties of the main physiological types of motor units (MUs) that contribute to these muscle adaptations. Although the contractile profile of MU muscle fibers is tightly coupled to myosin heavy chain (MyHC) protein expression, it is not well understood if MyHC transition is a prerequisite for modifications to the contractile characteristics of MUs. In this study, we examined MU contractile properties, the mRNA expression of MyHC, parvalbumin, and sarcoendoplasmic reticulum Ca 2+ pump isoforms, as well as the MyHC protein content after 5 wk of volitional progressive weight-lifting training in the medial gastrocnemius muscle in rats. The training had no effect on MyHC profiling or Ca 2+ -handling protein gene expression. Maximum force increased in slow (by 49%) and fast (by 21%) MUs. Within fast MUs, the maximum force increased in most fatigue-resistant and intermediate but not most fatigable MUs. Twitch contraction time was shortened in slow and fast fatigue-resistant MUs. Twitch half-relaxation was shortened in fast most fatigue-resistant and intermediate MUs. The force-frequency curve shifted rightward in fast fatigue-resistant MUs. Fast fatigable MUs fatigued less within the initial 15 s while fast fatigue-resistant units increased the ability to potentiate the force within the first minute of the standard fatigue test. In conclusion, at the early stage of resistance training, modifications to the contractile characteristics of MUs appear in the absence of MyHC transition and the upregulation of Ca 2+ -handling genes. Copyright © 2016 the American Physiological Society.

Myosin binding protein-C activates thin filaments and inhibits thick filaments in heart muscle cells.

Science.gov (United States)

Kampourakis, Thomas; Yan, Ziqian; Gautel, Mathias; Sun, Yin-Biao; Irving, Malcolm

2014-12-30

Myosin binding protein-C (MyBP-C) is a key regulatory protein in heart muscle, and mutations in the MYBPC3 gene are frequently associated with cardiomyopathy. However, the mechanism of action of MyBP-C remains poorly understood, and both activating and inhibitory effects of MyBP-C on contractility have been reported. To clarify the function of the regulatory N-terminal domains of MyBP-C, we determined their effects on the structure of thick (myosin-containing) and thin (actin-containing) filaments in intact sarcomeres of heart muscle. We used fluorescent probes on troponin C in the thin filaments and on myosin regulatory light chain in the thick filaments to monitor structural changes associated with activation of demembranated trabeculae from rat ventricle by the C1mC2 region of rat MyBP-C. C1mC2 induced larger structural changes in thin filaments than calcium activation, and these were still present when active force was blocked with blebbistatin, showing that C1mC2 directly activates the thin filaments. In contrast, structural changes in thick filaments induced by C1mC2 were smaller than those associated with calcium activation and were abolished or reversed by blebbistatin. Low concentrations of C1mC2 did not affect resting force but increased calcium sensitivity and reduced cooperativity of force and structural changes in both thin and thick filaments. These results show that the N-terminal region of MyBP-C stabilizes the ON state of thin filaments and the OFF state of thick filaments and lead to a novel hypothesis for the physiological role of MyBP-C in the regulation of cardiac contractility.

Slow and fast fatigable frog muscle fibres: electrophysiological and histochemical characteristics.

Science.gov (United States)

Vydevska-Chichova, M; Mileva, K; Todorova, R; Dimitrova, M; Radicheva, N

2005-12-01

Continuous activity of isolated frog gastrocnemius muscle fibres provoked by repetitive stimulation of 5 Hz was used as an experimental model for fatigue development in different fibre types. Parameter changes of the elicited intracellular action potentials and mechanical twitches during the period of uninterrupted activity were used as criteria for fatigue evaluation. Slow fatigable muscle fibre (SMF) and fast fatigable muscle fibre (FMF) types were distinguished depending on the duration of their uninterrupted activity, which was significantly longer in SMFs than in FMFs. The normalized changes of action potential amplitude and duration were significantly smaller in FMFs than in SMFs. The average twitch force and velocity of contraction and relaxation were significantly higher in FMFs than in SMFs. Myosin ATPase (mATPase) and succinate dehydrogenase activity were studied by histochemical assessment in order to validate the fibre type classification based on their electrophysiological characteristics. Based on the relative mATPase reactivity, the fibres of the studied muscle were classified as one of five different types (1-2, 2, 2-3, 3 and tonic). Smaller sized fibres (tonic and type 3) expressed higher succinate dehydrogenase activity than larger sized fibres (type 1-2, 2), which is related to the fatigue resistance. The differences between fatigue development in SMFs and FMFs during continuous activity were associated with fibre-type specific mATPase and succinate dehydrogenase activity.

Public Health and Rodents: A Game of Cat and Mouse

NARCIS (Netherlands)

Meerburg, B.G.

2015-01-01

Rodents are the most abundant order of living mammals, distributed on every continent except Antarctic and represent 43 % of all mammalian species. Beside causing food losses and infrastructural damage, rodents can harbour pathogens that may cause serious problems to human and animal health.

Septin 7 reduces nonmuscle myosin IIA activity in the SNAP23 complex and hinders GLUT4 storage vesicle docking and fusion

Energy Technology Data Exchange (ETDEWEB)

Wasik, Anita A.; Dumont, Vincent [Department of Pathology, University of Helsinki, 00014 Helsinki (Finland); Tienari, Jukka [Department of Pathology, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, 05850 Hyvinkää (Finland); Nyman, Tuula A. [Institute of Biotechnology, University of Helsinki, 00014 Helsinki (Finland); Fogarty, Christopher L.; Forsblom, Carol; Lehto, Markku [Folkhälsan Institute of Genetics, Folkhälsan Research Center, 00290 Helsinki (Finland); Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, 000290 Helsinki (Finland); Diabetes& Obesity Research Program, Research Program´s Unit, 00014 University of Helsinki (Finland); Lehtonen, Eero [Department of Pathology, University of Helsinki, 00014 Helsinki (Finland); Laboratory Animal Centre, University of Helsinki, 00014 Helsinki (Finland); Groop, Per-Henrik [Folkhälsan Institute of Genetics, Folkhälsan Research Center, 00290 Helsinki (Finland); Abdominal Center Nephrology, University of Helsinki and Helsinki University Hospital, 000290 Helsinki (Finland); Diabetes& Obesity Research Program, Research Program´s Unit, 00014 University of Helsinki (Finland); Baker IDI Heart & Diabetes Institute, 3004 Melbourne (Australia); Lehtonen, Sanna, E-mail: sanna.h.lehtonen@helsinki.fi [Department of Pathology, University of Helsinki, 00014 Helsinki (Finland)

2017-01-15

Glomerular epithelial cells, podocytes, are insulin responsive and can develop insulin resistance. Here, we demonstrate that the small GTPase septin 7 forms a complex with nonmuscle myosin heavy chain IIA (NMHC-IIA; encoded by MYH9), a component of the nonmuscle myosin IIA (NM-IIA) hexameric complex. We observed that knockdown of NMHC-IIA decreases insulin-stimulated glucose uptake into podocytes. Both septin 7 and NM-IIA associate with SNAP23, a SNARE protein involved in GLUT4 storage vesicle (GSV) docking and fusion with the plasma membrane. We observed that insulin decreases the level of septin 7 and increases the activity of NM-IIA in the SNAP23 complex, as visualized by increased phosphorylation of myosin regulatory light chain. Also knockdown of septin 7 increases the activity of NM-IIA in the complex. The activity of NM-IIA is increased in diabetic rat glomeruli and cultured human podocytes exposed to macroalbuminuric sera from patients with type 1 diabetes. Collectively, the data suggest that the activity of NM-IIA in the SNAP23 complex plays a key role in insulin-stimulated glucose uptake into podocytes. Furthermore, we observed that septin 7 reduces the activity of NM-IIA in the SNAP23 complex and thereby hinders GSV docking and fusion with the plasma membrane. - Highlights: • Septin 7, nonmuscle myosin heavy chain IIA (NMHC-IIA) and SNAP23 form a complex. • Knockdown of septin 7 increases NM-IIA activity in the SNAP23 complex. • Insulin decreases septin 7 level and increases NM-IIA activity in the SNAP23 complex. • Septin 7 hinders GSV docking/fusion by reducing NM-IIA activity in the SNAP23 complex.

Septin 7 reduces nonmuscle myosin IIA activity in the SNAP23 complex and hinders GLUT4 storage vesicle docking and fusion

International Nuclear Information System (INIS)

Wasik, Anita A.; Dumont, Vincent; Tienari, Jukka; Nyman, Tuula A.; Fogarty, Christopher L.; Forsblom, Carol; Lehto, Markku; Lehtonen, Eero; Groop, Per-Henrik; Lehtonen, Sanna

2017-01-01

Glomerular epithelial cells, podocytes, are insulin responsive and can develop insulin resistance. Here, we demonstrate that the small GTPase septin 7 forms a complex with nonmuscle myosin heavy chain IIA (NMHC-IIA; encoded by MYH9), a component of the nonmuscle myosin IIA (NM-IIA) hexameric complex. We observed that knockdown of NMHC-IIA decreases insulin-stimulated glucose uptake into podocytes. Both septin 7 and NM-IIA associate with SNAP23, a SNARE protein involved in GLUT4 storage vesicle (GSV) docking and fusion with the plasma membrane. We observed that insulin decreases the level of septin 7 and increases the activity of NM-IIA in the SNAP23 complex, as visualized by increased phosphorylation of myosin regulatory light chain. Also knockdown of septin 7 increases the activity of NM-IIA in the complex. The activity of NM-IIA is increased in diabetic rat glomeruli and cultured human podocytes exposed to macroalbuminuric sera from patients with type 1 diabetes. Collectively, the data suggest that the activity of NM-IIA in the SNAP23 complex plays a key role in insulin-stimulated glucose uptake into podocytes. Furthermore, we observed that septin 7 reduces the activity of NM-IIA in the SNAP23 complex and thereby hinders GSV docking and fusion with the plasma membrane. - Highlights: • Septin 7, nonmuscle myosin heavy chain IIA (NMHC-IIA) and SNAP23 form a complex. • Knockdown of septin 7 increases NM-IIA activity in the SNAP23 complex. • Insulin decreases septin 7 level and increases NM-IIA activity in the SNAP23 complex. • Septin 7 hinders GSV docking/fusion by reducing NM-IIA activity in the SNAP23 complex.

First Isolates of Leptospira spp., from Rodents Captured in Angola

Science.gov (United States)

Fortes-Gabriel, Elsa; Carreira, Teresa; Vieira, Maria Luísa

2016-01-01

Rodents play an important role in the transmission of pathogenic Leptospira spp. However, in Angola, neither the natural reservoirs of these spirochetes nor leptospirosis diagnosis has been considered. Regarding this gap, we captured rodents in Luanda and Huambo provinces to identify circulating Leptospira spp. Rodent kidney tissue was cultured and DNA amplified and sequenced. Culture isolates were evaluated for pathogenic status and typing with rabbit antisera; polymerase chain reaction (PCR) and sequencing were also performed. A total of 37 rodents were captured: Rattus rattus (15, 40.5%), Rattus norvegicus (9, 24.3%), and Mus musculus (13, 35.2%). Leptospiral DNA was amplified in eight (21.6%) kidney samples. From the cultures, we obtained four (10.8%) Leptospira isolates belonging to the Icterohaemorrhagiae and Ballum serogroups of Leptospira interrogans and Leptospira borgpetersenii genospecies, respectively. This study provides information about circulating leptospires spread by rats and mice in Angola. PMID:26928840

Harmonic Force Spectroscopy Reveals a Force-Velocity Curve from a Single Human Beta Cardiac Myosin Motor

DEFF Research Database (Denmark)

Sung, Jongmin; Nag, Suman; Vestergaard, Christian L.

2014-01-01

human beta cardiac myosin S1. We also compare load-velocity curves for wild-type motors with load-velocity curves of mutant forms that cause hypertrophic or dilated-cardiomyopathy (HCM or DCM), in order to understand the effects of mutations on the contractile cycle at the single molecule level....

Matching of sarcoplasmic reticulum and contractile properties in rat fast- and slow-twitch muscle fibres.

Science.gov (United States)

Trinh, Huong H; Lamb, Graham D

2006-07-01

1. The twitch characteristics (fast-twitch or slow-twitch) of skeletal muscle fibres are determined not only by the contractile apparatus properties of the fibre, but also by the time-course of Ca2+ release and re-uptake by the sarcoplasmic reticulum (SR). The present study examined, in individual fibres from non-transforming muscle of the rat, whether particular SR properties are matched to the contractile apparatus properties of the fibre, in particular in the case of fibres with fast-twitch contractile apparatus located in a slow-twitch muscle, namely the soleus. 2. Force was recorded in single, mechanically skinned fibres from extensor digitorum longus (EDL), gastrocnemius, peroneus longus and soleus muscles. Using repeated cycles in which the SR was emptied of all releasable Ca2+ and then reloaded, it was possible to determine the relative amount of Ca2+ present in the SR endogenously, the maximum SR capacity and the rate of Ca2+ loading. The sensitivity of the contractile apparatus to Ca2+ and Sr2+ was used to classify the fibres as fast-twitch (FT), slow-twitch (ST) or mixed (fibres examined) and thereby identify the likely troponin C and myosin heavy chain types present. 3. There was no significant difference in SR properties between the groups of FT fibres obtained from the four different muscles, including soleus. Despite some overlap in the SR properties of individual fibres between the FT and ST groups, the properties of the FT fibres in all four muscles studied were significantly different from those of the ST and mixed fibres. 4. In general, in FT fibres the SR had a larger capacity and the endogenous Ca2+ content was a relatively lower percentage of maximum compared with ST fibres. Importantly, in terms of their SR properties, FT fibres from soleus muscle more closely resembled FT fibres from other muscles than they did ST fibres from soleus muscle.

Molecular Survey of Zoonotic Agents in Rodents and Other Small Mammals in Croatia.

Science.gov (United States)

Tadin, Ante; Tokarz, Rafal; Markotić, Alemka; Margaletić, Josip; Turk, Nenad; Habuš, Josipa; Svoboda, Petra; Vucelja, Marko; Desai, Aaloki; Jain, Komal; Lipkin, W Ian

2016-02-01

Croatia is a focus for many rodent-borne zoonosis. Here, we report a survey of 242 rodents and small mammals, including 43 Myodes glareolus, 131 Apodemus flavicollis, 53 Apodemus agrarius, three Apodemus sylvaticus, six Sorex araneus, four Microtus arvalis, one Microtus agrestis, and one Muscardinus avellanarius, collected at eight sites in Croatia over an 8-year period. Multiplex MassTag polymerase chain reaction (PCR) was used for detection of Borrelia, Rickettsia, Bartonella, Babesia, Ehrlichia, Anaplasma, Francisella tularensis, and Coxiella burnetii. Individual PCR assays were used for detection of Leptospira, lymphocytic choriomeningitis virus, orthopoxviruses, flaviviruses, hantaviruses, and Toxoplasma gondii. Of the rodents, 52 (21.5%) were infected with Leptospira, 9 (3.7%) with Borrelia miyamotoi, 5 (2%) with Borrelia afzelii, 29 (12.0%) with Bartonella, 8 (3.3%) with Babesia microti, 2 (0.8%) with Ehrlichia, 4 (1.7%) with Anaplasma, 2 (0.8%) with F. tularensis, 43 (17.8%) with hantaviruses, and 1 (0.4%) with an orthopoxvirus. Other agents were not detected. Multiple infections were found in 32 rodents (13.2%): dual infections in 26 rodents (10.7%), triple infections in four rodents (2.9%), and quadruple infections in two rodents (0.8%). Our findings indicate that rodents in Croatia harbor a wide range of bacteria and viruses that are pathogenic to humans. © The American Society of Tropical Medicine and Hygiene.

A Collapsin Response Mediator Protein 2 Isoform Controls Myosin II-Mediated Cell Migration and Matrix Assembly by Trapping ROCK II

Science.gov (United States)

Morgan-Fisher, Marie; Wait, Robin; Couchman, John R.; Wewer, Ulla M.

2012-01-01

Collapsin response mediator protein 2 (CRMP-2) is known as a regulator of neuronal polarity and differentiation through microtubule assembly and trafficking. Here, we show that CRMP-2 is ubiquitously expressed and a splice variant (CRMP-2L), which is expressed mainly in epithelial cells among nonneuronal cells, regulates myosin II-mediated cellular functions, including cell migration. While the CRMP-2 short form (CRMP-2S) is recognized as a substrate of the Rho-GTP downstream kinase ROCK in neuronal cells, a CRMP-2 complex containing 2L not only bound the catalytic domain of ROCK II through two binding domains but also trapped and inhibited the kinase. CRMP-2L protein levels profoundly affected haptotactic migration and the actin-myosin cytoskeleton of carcinoma cells as well as nontransformed epithelial cell migration in a ROCK activity-dependent manner. Moreover, the ectopic expression of CRMP-2L but not -2S inhibited fibronectin matrix assembly in fibroblasts. Underlying these responses, CRMP-2L regulated the kinase activity of ROCK II but not ROCK I, independent of GTP-RhoA levels. This study provides a new insight into CRMP-2 as a controller of myosin II-mediated cellular functions through the inhibition of ROCK II in nonneuronal cells. PMID:22431514

Wild Rodents as Experimental Intermediate Hosts of Lagochilascaris minor Leiper, 1909

Directory of Open Access Journals (Sweden)

Julieta Machado Paçô

1999-07-01

Full Text Available A total of 25 specimens of Cavia porcellus (guinea pig, 5 Dasyprocta agouti (agouti, and 22 Calomys callosus (vesper mice were inoculated with infective eggs of Lagochilascaris minor. The inoculum was prepared with embryonated eggs and orally administered to each individual animal through an esophagus probe. In parallel, 100 specimens of Felis catus domesticus were individually fed with 55-70 nodules containing 3rd-stage larvae encysted in tissues of infected rodents. Animals were examined and necropsied at different time intervals. The migration and encystment of L3 larva was observed in viscera, skeletal muscle, adipose and subcutaneous tissues from all rodents. Adult worms localized at abscesses in the cervical region, rhino, and oropharynx were recovered from domestic cats inoculated with infected rodent tissues. Through this study we can conclude that: (1 wild rodents act as intermediate hosts, characterizing this ascarid heteroxenic cycle; (2 in natural conditions rodents could possibly act as either intermediate hosts or paratenic hosts of Lagochilascaris minor; (3 despite the occurrence of an auto-infecting cycle, in prime-infection of felines (definite hosts the cycle is only completed when intermediate hosts are provided; and (4 in the wild, rodents could serve as a source of infection for humans as they are frequently used as food in regions with the highest incidence of human lagochilascariasis.

Mathematical modeling of Myosin induced bistability of Lamellipodial fragments.

Science.gov (United States)

Hirsch, S; Manhart, A; Schmeiser, C

2017-01-01

For various cell types and for lamellipodial fragments on flat surfaces, externally induced and spontaneous transitions between symmetric nonmoving states and polarized migration have been observed. This behavior is indicative of bistability of the cytoskeleton dynamics. In this work, the Filament Based Lamellipodium Model (FBLM), a two-dimensional, anisotropic, two-phase continuum model for the dynamics of the actin filament network in lamellipodia, is extended by a new description of actin-myosin interaction. For appropriately chosen parameter values, the resulting model has bistable dynamics with stable states showing the qualitative features observed in experiments. This is demonstrated by numerical simulations and by an analysis of a strongly simplified version of the FBLM with rigid filaments and planar lamellipodia at the cell front and rear.

Lessons from a tarantula: new insights into muscle thick filament and myosin interacting-heads motif structure and function.

Science.gov (United States)

Alamo, Lorenzo; Koubassova, Natalia; Pinto, Antonio; Gillilan, Richard; Tsaturyan, Andrey; Padrón, Raúl

2017-10-01

The tarantula skeletal muscle X-ray diffraction pattern suggested that the myosin heads were helically arranged on the thick filaments. Electron microscopy (EM) of negatively stained relaxed tarantula thick filaments revealed four helices of heads allowing a helical 3D reconstruction. Due to its low resolution (5.0 nm), the unambiguous interpretation of densities of both heads was not possible. A resolution increase up to 2.5 nm, achieved by cryo-EM of frozen-hydrated relaxed thick filaments and an iterative helical real space reconstruction, allowed the resolving of both heads. The two heads, "free" and "blocked", formed an asymmetric structure named the "interacting-heads motif" (IHM) which explained relaxation by self-inhibition of both heads ATPases. This finding made tarantula an exemplar system for thick filament structure and function studies. Heads were shown to be released and disordered by Ca 2+ -activation through myosin regulatory light chain phosphorylation, leading to EM, small angle X-ray diffraction and scattering, and spectroscopic and biochemical studies of the IHM structure and function. The results from these studies have consequent implications for understanding and explaining myosin super-relaxed state and thick filament activation and regulation. A cooperative phosphorylation mechanism for activation in tarantula skeletal muscle, involving swaying constitutively Ser35 mono-phosphorylated free heads, explains super-relaxation, force potentiation and post-tetanic potentiation through Ser45 mono-phosphorylated blocked heads. Based on this mechanism, we propose a swaying-swinging, tilting crossbridge-sliding filament for tarantula muscle contraction.

Responses of nocturnal rodents to shrub encroachment in Banni grasslands, Gujarat, India

Science.gov (United States)

Jayadevan, A.

2016-12-01

Shrub encroachment is one of the greatest threats to grasslands globally. These woodlands can strongly influence the behaviour of small mammals adapted to more open habitats, which rely on high visibility for early detection of predators. In semi-arid grasslands, rodents are considered keystone species. Although shrub encroachment is known to negatively affect rodent assemblages, its impact on the foraging behaviour of rodents, which is known to vary in response to risky situations, is unknown. Understanding whether shrub encroachment alters such antipredator behaviour is important as antipredator behaviour can alter the distribution, abundance and ultimately, survival of prey species. In this study, I explored the effects of shrub encroachment on the foraging behaviour of nocturnal rodent communities in the Banni grasslands, India. I examined foraging behaviour, quantified using the giving-up density (GUD) framework and the number of rodent crossings around food patches, in two habitats that differed in the extent of shrub encroachment. Under the GUD framework, the amount of food left behind by a forager in a food patch reflects the costs of feeding at the patch. Higher GUDs imply higher foraging costs. I also investigated how removal of an invasive woody plant, Prosopis juliflora would affect foraging behaviour of nocturnal rodents. High shrub encroachment was associated with higher foraging costs (higher GUDs) and lower activity than the sparsely wooded habitat, likely due to low visibility in the densely wooded habitat. The dense habitat also supported a higher richness and relative abundance of generalist rodents than the sparse habitat, likely due to the increased heterogeneity of the habitat. The tree removal experiment revealed that rodents had lower GUDs (i.e., low foraging costs) after the event of tree cutting. This may be due to the reduction of cover in the habitat, leading to higher visibility and lower predation risk. My results suggest that shrub

Effect of woodland patch size on rodent seed predation in a fragmented landscape

Directory of Open Access Journals (Sweden)

J. Loman

2007-05-01

Full Text Available Predation on large woody plant seeds; chestnuts, acorns and sloe kernels, was studied in deciduous forests of two size classes: small woodlots (<1 ha and large woods (at least 25 ha in southern Sweden. Seeds used for the study were artificially distributed on the forest ground and seed predation measured as seed removal. Predation rate was similar in both types of woods. However, rodent density was higher in small woodlots and a correction for differences in rodent density showed that predation rate per individual rodent was higher in the large woods. This suggests that the small woodlots (including the border zone and their adjacent fields have more rodent food per area unit. A small woodlot cannot be considered a representative sample of a large continuous forest, even if the habitats appear similar. There was a strong effect of rodent density on seed predation rate. This suggests that rodents are major seed predators in this habitat.

Rodent Species Distribution and Hantavirus Seroprevalence in Residential and Forested areas of Sarawak, Malaysia.

Science.gov (United States)

Hamdan, Nur Elfieyra Syazana; Ng, Yee Ling; Lee, Wei Bin; Tan, Cheng Siang; Khan, Faisal Ali Anwarali; Chong, Yee Ling

2017-01-01

Rodents belong to the order Rodentia, which consists of three families in Borneo (i.e., Muridae, Sciuridae and Hystricidae). These include rats, mice, squirrels, and porcupines. They are widespread throughout the world and considered pests that harm humans and livestock. Some rodent species are natural reservoirs of hantaviruses (Family: Bunyaviridae) that can cause zoonotic diseases in humans. Although hantavirus seropositive human sera were reported in Peninsular Malaysia in the early 1980s, information on their infection in rodent species in Malaysia is still lacking. The rodent populations in residential and forested areas in Sarawak were sampled. A total of 108 individuals from 15 species of rodents were collected in residential ( n = 44) and forested ( n = 64) areas. The species diversity of rodents in forested areas was significantly higher (H = 2.2342) compared to rodents in residential areas (H = 0.64715) ( p Sarawak, East Malaysia. The results suggested that hantavirus was not circulating in the studied rodent populations in Sarawak, or it was otherwise at a low prevalence that is below the detection threshold. It is important to remain vigilant because of the zoonotic potential of this virus and its severe disease outcome. Further studies, such as molecular detection of viral genetic materials, are needed to fully assess the risk of hantavirus infection in rodents and humans in this region of Malaysia.

Nutritional Evaluation of NASA's Rodent Food Bar Diet

Science.gov (United States)

Barrett, Joyce E.; Yu, Diane S.; Dalton, Bonnie P.

2000-01-01

Tests are being conducted on NASA's rodent Food Bar in preparation for long-term use as the rat and mouse diet aboard the International Space Station. Nutritional analyses are performed after the bars are manufactured and then repeated periodically to determine nutritional stability. The primary factors analyzed are protein, ash, fat, fiber, moisture, amino acids, fatty acids, and minerals. Nutrient levels are compared to values published in the National Research Council's dietary requirements for rodents, and also to those contained in several commonly used commercial rodent lab diets. The Food Bar is manufactured from a powdered diet to which moisture is added as it is processed through an extruder. The bars are dipped into potassium sorbate, vacuum-sealed, and irradiated. In order to determine nutrient changes during extrusion and irradiation, the powdered diet, the non-irradiated bars, and the irradiated bars are all analyzed. We have observed lower values for some nutrients (iodine, vitamin K, and iron) in the Food Bars compared with NRC requirements. Many nutrients in the Food Bars are contained at a higher level than levels in the NRC requirements. An additional factor we are investigating is the 26% moisture level in the Food Bars, which drops to about 15% within a week, compared to a stable 10% moisture in many standard lab chow diets. In addition to the nutritional analyses, the food bar is being fed to several strains of rats and mice, and feeding study and necropsy results are being observed (Barrett et al, unpublished data). Information from the nutritional analyses and from the rodent studies will enable us to recommend the formulation that will most adequately meet the rodent Food Bar requirements for long-term use aboard the Space Station.

The hip adductor muscle group in caviomorph rodents: anatomy and homology.

Science.gov (United States)

García-Esponda, César M; Candela, Adriana M

2015-06-01

Anatomical comparative studies including myological data of caviomorph rodents are relatively scarce, leading to a lack of use of muscular features in cladistic and morphofunctional analyses. In rodents, the hip adductor muscles constitute an important group of the hindlimb musculature, having an important function during the beginning of the stance phase. These muscles are subdivided in several distinct ways in the different clades of rodents, making the identification of their homologies hard to establish. In this contribution we provide a detailed description of the anatomical variation of the hip adductor muscle group of different genera of caviomorph rodents and identify the homologies of these muscles in the context of Rodentia. On this basis, we identify the characteristic pattern of the hip adductor muscles in Caviomorpha. Our results indicate that caviomorphs present a singular pattern of the hip adductor musculature that distinguishes them from other groups of rodents. They are characterized by having a single m. adductor brevis that includes solely its genicular part. This muscle, together with the m. gracilis, composes a muscular sheet that is medial to all other muscles of the hip adductor group. Both muscles probably have a synergistic action during locomotion, where the m. adductor brevis reinforces the multiple functions of the m. gracilis in caviomorphs. Mapping of analyzed myological characters in the context of Rodentia indicates that several features are recovered as potential synapomorphies of caviomorphs. Thus, analysis of the myological data described here adds to the current knowledge of caviomorph rodents from anatomical and functional points of view, indicating that this group has features that clearly differentiate them from other rodents. Copyright © 2015 Elsevier GmbH. All rights reserved.

Helminth Infections of Rodents and Their Zoonotic Importance in Boyer-Ahmad District, Southwestern Iran.

Science.gov (United States)

Ranjbar, Mohammad Javad; Sarkari, Bahador; Mowlavi, Gholam Reza; Seifollahi, Zeinab; Moshfe, Abdolali; Abdolahi Khabisi, Samaneh; Mobedi, Iraj

2017-01-01

Rodents are considered as reservoirs of various zoonotic diseases including helminthic infections. The current study aimed to evaluate the prevalence of helminth infections in rodents, in Boyer-Ahmad district, Southwestern Iran. Overall, 52 rodents were captured from various areas of the district by Sherman live traps. The animals were then euthanized and dissected. During necropsy, each organ was examined macroscopically for presence of any cyst or visible parasite. The gastrointestinal tract was removed and their contents were evaluated for larva or adult worms. Trichinella larvae in the rodents' muscles were investigated by both digestion and pathological methods. Twenty-eight (53.8%) of the trapped rodents were male. The rodents were including 25 (48.1%) Meriones persicus , 1(1.9%) Calomyscus bailwardi , 1 (1.9%) Arvicola terresterris , 7 (13.5%) Rattus rattus , 8 (15.4%) R. norvegicus , and 10 (19.2%) Apodemus sylvaticus . Of them, 38 (73.0%) were infected with at least one helminth. Collected rodents were infected with Hymenolepis diminuta (50%), Hymenolepis nana fraterna (28.8%), Skrjabinotaenia sp. (15.4%), Anoplocephalidae sp. (15.4%), Cysticercus fasciolaris (5.8%), Trichuris muris (36.5%), Aspiculuris tetraptera (15.4%), Syphacia sp. (5.7%), Rictularia sp. (15.4%), Trichostrongylus sp. (3.8%), and Gongylonema sp. (3.8%). M. persicus was the most (84%) infected rodent, yet the differences between rodent genus and helminth infectivity were not statistically significant ( P >0.05). The rodents in Boyer-Ahmad district are infected with different helminths infections that some of them are recognized as threat to human health.

Bone morphology of the hind limbs in two caviomorph rodents.

Science.gov (United States)

de Araújo, F A P; Sesoko, N F; Rahal, S C; Teixeira, C R; Müller, T R; Machado, M R F

2013-04-01

In order to evaluate the hind limbs of caviomorph rodents a descriptive analysis of the Cuniculus paca (Linnaeus, 1766) and Hydrochoerus hydrochaeris (Linnaeus, 1766) was performed using anatomical specimens, radiography, computed tomography (CT) and full-coloured prototype models to generate bone anatomy data. The appendicular skeleton of the two largest rodents of Neotropical America was compared with the previously reported anatomical features of Rattus norvegicus (Berkenhout, 1769) and domestic Cavia porcellus (Linnaeus, 1758). The structures were analyzed macroscopically and particular findings of each species reported. Features including the presence of articular fibular projection and lunulae were observed in the stifle joint of all rodents. Imaging aided in anatomical description and, specifically in the identification of bone structures in Cuniculus paca and Hydrochoerus hydrochaeris. The imaging findings were correlated with the anatomical structures observed. The data may be used in future studies comparing these animals to other rodents and mammalian species. © 2012 Blackwell Verlag GmbH.

First Isolates of Leptospira spp., from Rodents Captured in Angola.

Science.gov (United States)

Fortes-Gabriel, Elsa; Carreira, Teresa; Vieira, Maria Luísa

2016-05-04

Rodents play an important role in the transmission of pathogenic Leptospira spp. However, in Angola, neither the natural reservoirs of these spirochetes nor leptospirosis diagnosis has been considered. Regarding this gap, we captured rodents in Luanda and Huambo provinces to identify circulating Leptospira spp. Rodent kidney tissue was cultured and DNA amplified and sequenced. Culture isolates were evaluated for pathogenic status and typing with rabbit antisera; polymerase chain reaction (PCR) and sequencing were also performed. A total of 37 rodents were captured: Rattus rattus (15, 40.5%), Rattus norvegicus (9, 24.3%), and Mus musculus (13, 35.2%). Leptospiral DNA was amplified in eight (21.6%) kidney samples. From the cultures, we obtained four (10.8%) Leptospira isolates belonging to the Icterohaemorrhagiae and Ballum serogroups of Leptospira interrogans and Leptospira borgpetersenii genospecies, respectively. This study provides information about circulating leptospires spread by rats and mice in Angola. © The American Society of Tropical Medicine and Hygiene.

Rodent Research on the International Space Station - A Look Forward

Science.gov (United States)

Kapusta, A. B.; Smithwick, M.; Wigley, C. L.

2014-01-01

Rodent Research on the International Space Station (ISS) is one of the highest priority science activities being supported by NASA and is planned for up to two flights per year. The first Rodent Research flight, Rodent Research-1 (RR-1) validates the hardware and basic science operations (dissections and tissue preservation). Subsequent flights will add new capabilities to support rodent research on the ISS. RR-1 will validate the following capabilities: animal husbandry for up to 30 days, video downlink to support animal health checks and scientific analysis, on-orbit dissections, sample preservation in RNA. Later and formalin, sample transfer from formalin to ethanol (hindlimbs), rapid cool-down and subsequent freezing at -80 of tissues and carcasses, sample return and recovery. RR-2, scheduled for SpX-6 (Winter 20142015) will add the following capabilities: animal husbandry for up to 60 days, RFID chip reader for individual animal identification, water refill and food replenishment, anesthesia and recovery, bone densitometry, blood collection (via cardiac puncture), blood separation via centrifugation, soft tissue fixation in formalin with transfer to ethanol, and delivery of injectable drugs that require frozen storage prior to use. Additional capabilities are also planned for future flights and these include but are not limited to male mice, live animal return, and the development of experiment unique equipment to support science requirements for principal investigators that are selected for flight. In addition to the hardware capabilities to support rodent research the Crew Office has implemented a training program in generic rodent skills for all USOS crew members during their pre-assignment training rotation. This class includes training in general animal handling, euthanasia, injections, and dissections. The dissection portion of this training focuses on the dissection of the spleen, liver, kidney with adrenals, brain, eyes, and hindlimbs. By achieving and

Public health implications of changing rodent importation patterns— United States, 1999–2013

Science.gov (United States)

Lankau, Emily W.; Sinclair, Julie R.; Schroeder, Betsy A.; Galland, G. Gale; Marano, Nina

2015-01-01

Summary The United States imports a large volume of live wild and domestic animal species; these animals pose a demonstrated risk for introduction of zoonotic diseases. Rodents are imported for multiple purposes, including scientific research, zoo exhibits, and the pet trade. Current U.S. public health regulatory restrictions specific to rodent importation pertain only to those of African origin. To understand the impacts of these regulations and the potential public health risks of international rodent trade to the United States, we evaluated live rodent import records during 1999 –2013 by shipment volume and geographic origin, source (e.g., wild -caught versus captive-or commercially bred), intended purpose, and rodent taxonomy. Live rodent imports increased from 2,737 animals during 1999 to 173,761 animals during 2013. Increases in both the number and size of shipments contributed to this trend. The proportion of wild-captured imports declined from 75% during 1999 to guinea pigs, and hamsters arriving from other countries in North America were predominant taxa underlying this trend . After 2003, African-origin imports became sporadic events under the federal permit process. These patterns suggest development of large -scale captive rodent breeding markets abroad for commercial sale in the United States. While the shift from wild-captured imports alleviates many conservation concerns and risks for novel disease emergence, such consolidated sourcing might elevate exposure risks for zoonotic diseases associated with high-density rodent breeding(e.g. , lymphocytic choriomeningitis or salmonellosis). A responsive border health system must periodically re-evaluate importation regulations in conjunction with key stakeholders to ensure a balance between the economic benefits of rodent trade against the potential public health risks. PMID:26245515

Harvesting behaviour of three central European rodents: Identifying the rodent pest in cereals

Czech Academy of Sciences Publication Activity Database

Heroldová, Marta; Tkadlec, Emil

2011-01-01

Roč. 30, č. 1 (2011), s. 82-84 ISSN 0261-2194 R&D Projects: GA MZe QH72075 Institutional research plan: CEZ:AV0Z60930519 Keywords : Apodemus sylvaticus * Apodemus uralensis * feeding behaviour * lab experiments * Microtus arvalis * rodent pest control Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 1.402, year: 2011

Slow briefs: slow food....slow architecture

OpenAIRE

Crotch, Joanna

2012-01-01

We are moving too fast…fast lives, fast cars, fast food…..and fast architecture. We are caught up in a world that allows no time to stop and think; to appreciate and enjoy all the really important things in our lives. Recent responses to this seemingly unstoppable trend are the growing movements of Slow Food and Cittaslow. Both initiatives are, within their own realms, attempting to reverse speed, homogeny, expediency and globalisation, considering the values of regionality, patience, craft, ...

Protein Supplementation Does Not Further Increase Latissimus Dorsi Muscle Fiber Hypertrophy after Eight Weeks of Resistance Training in Novice Subjects, but Partially Counteracts the Fast-to-Slow Muscle Fiber Transition

Directory of Open Access Journals (Sweden)

Antonio Paoli

2016-06-01

Full Text Available The response to resistance training and protein supplementation in the latissimus dorsi muscle (LDM has never been investigated. We investigated the effects of resistance training (RT and protein supplementation on muscle mass, strength, and fiber characteristics of the LDM. Eighteen healthy young subjects were randomly assigned to a progressive eight-week RT program with a normal protein diet (NP or high protein diet (HP (NP 0.85 vs. HP 1.8 g of protein·kg−1·day−1. One repetition maximum tests, magnetic resonance imaging for cross-sectional muscle area (CSA, body composition, and single muscle fibers mechanical and phenotype characteristics were measured. RT induced a significant gain in strength (+17%, p < 0.0001, whole muscle CSA (p = 0.024, and single muscle fibers CSA (p < 0.05 of LDM in all subjects. Fiber isometric force increased in proportion to CSA (+22%, p < 0.005 and thus no change in specific tension occurred. A significant transition from 2X to 2A myosin expression was induced by training. The protein supplementation showed no significant effects on all measured outcomes except for a smaller reduction of 2X myosin expression. Our results suggest that in LDM protein supplementation does not further enhance RT-induced muscle fiber hypertrophy nor influence mechanic muscle fiber characteristics but partially counteracts the fast-to-slow fiber shift.

The response of human and rodent cells to hyperthermia

International Nuclear Information System (INIS)

Roizin-Towle, L.; Pirro, J.P.

1991-01-01

Inherent cellular radiosensitivity in vitro has been shown to be a good predictor of human tumor response in vivo. In contrast, the importance of the intrinsic thermosensitivity of normal and neoplastic human cells as a factor in the responsiveness of human tumors to adjuvant hyperthermia has never been analyzed systematically. A comparison of thermal sensitivity and thermo-radiosensitization in four rodent and eight human-derived cell lines was made in vitro. Arrhenius plots indicated that the rodent cells were more sensitive to heat killing than the human, and the break-point was 0.5 degrees C higher for the human than rodent cells. The relationship between thermal sensitivity and the interaction of heat with X rays at low doses was documented by thermal enhancement ratios (TER's). Cells received either a 1 hr exposure to 43 degrees C or a 20 minute treatment at 45 degrees C before exposure to 300 kVp X rays. Thermal enhancement ratios ranged from 1.0 to 2.7 for human cells heated at 43 degrees C and from 2.1 to 5.3 for heat exposures at 45 degrees C. Thermal enhancement ratios for rodent cells were generally 2 to 3 times higher than for human cells, because of the fact that the greater thermosensitivity of rodent cells results in a greater enhancement of radiation damage. Intrinsic thermosensitivity of human cells has relevance to the concept of thermal dose; intrinsic thermo-radiosensitization of a range of different tumor cells is useful in documenting the interactive effects of radiation combined with heat

Cortical mechanics and myosin-II abnormalities associated with post-ovulatory aging: implications for functional defects in aged eggs

Science.gov (United States)

Mackenzie, Amelia C.L.; Kyle, Diane D.; McGinnis, Lauren A.; Lee, Hyo J.; Aldana, Nathalia; Robinson, Douglas N.; Evans, Janice P.

2016-01-01

STUDY HYPOTHESIS Cellular aging of the egg following ovulation, also known as post-ovulatory aging, is associated with aberrant cortical mechanics and actomyosin cytoskeleton functions. STUDY FINDING Post-ovulatory aging is associated with dysfunction of non-muscle myosin-II, and pharmacologically induced myosin-II dysfunction produces some of the same deficiencies observed in aged eggs. WHAT IS KNOWN ALREADY Reproductive success is reduced with delayed fertilization and when copulation or insemination occurs at increased times after ovulation. Post-ovulatory aged eggs have several abnormalities in the plasma membrane and cortex, including reduced egg membrane receptivity to sperm, aberrant sperm-induced cortical remodeling and formation of fertilization cones at the site of sperm entry, and reduced ability to establish a membrane block to prevent polyspermic fertilization. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Ovulated mouse eggs were collected at 21–22 h post-human chorionic gonadotrophin (hCG) (aged eggs) or at 13–14 h post-hCG (young eggs), or young eggs were treated with the myosin light chain kinase (MLCK) inhibitor ML-7, to test the hypothesis that disruption of myosin-II function could mimic some of the effects of post-ovulatory aging. Eggs were subjected to various analyses. Cytoskeletal proteins in eggs and parthenogenesis were assessed using fluorescence microscopy, with further analysis of cytoskeletal proteins in immunoblotting experiments. Cortical tension was measured through micropipette aspiration assays. Egg membrane receptivity to sperm was assessed in in vitro fertilization (IVF) assays. Membrane topography was examined by low-vacuum scanning electron microscopy (SEM). MAIN RESULTS AND THE ROLE OF CHANCE Aged eggs have decreased levels and abnormal localizations of phosphorylated myosin-II regulatory light chain (pMRLC; P = 0.0062). Cortical tension, which is mediated in part by myosin-II, is reduced in aged mouse eggs when compared with

Radioimmunoassay of myosin heavy beta chains in human serum for the evaluation of the size of myocardial infarction: correlation with myocardial Tl-201 SPECT and cardiac angioscintigraphy

International Nuclear Information System (INIS)

Facello, A.; Gries, P.; Demangeat, C.; Brunot, B.; Roul, G.; Demangeat, J.L.; Moulichon, M.; Bareiss, P.; Sacrez, A.; Constantinesco, A.

1990-01-01

To determine the relationship between serum levels of myosin heavy beta chains assessed by an IRMA technique and other radionuclide and enzymatic parameters in the evaluation of the size of myocardial infarction, we studied 22 patients with acute myocardial infarction. Blood samples taken daily between 1st to 13th day of evolution allow the determination of peak and integral of myosine release that showed a good correlation (p [fr

Visual Landmarks Facilitate Rodent Spatial Navigation in Virtual Reality Environments

Science.gov (United States)

Youngstrom, Isaac A.; Strowbridge, Ben W.

2012-01-01

Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain…

C0 and C1 N-terminal Ig domains of myosin binding protein C exert different effects on thin filament activation.

Science.gov (United States)

Harris, Samantha P; Belknap, Betty; Van Sciver, Robert E; White, Howard D; Galkin, Vitold E

2016-02-09

Mutations in genes encoding myosin, the molecular motor that powers cardiac muscle contraction, and its accessory protein, cardiac myosin binding protein C (cMyBP-C), are the two most common causes of hypertrophic cardiomyopathy (HCM). Recent studies established that the N-terminal domains (NTDs) of cMyBP-C (e.g., C0, C1, M, and C2) can bind to and activate or inhibit the thin filament (TF). However, the molecular mechanism(s) by which NTDs modulate interaction of myosin with the TF remains unknown and the contribution of each individual NTD to TF activation/inhibition is unclear. Here we used an integrated structure-function approach using cryoelectron microscopy, biochemical kinetics, and force measurements to reveal how the first two Ig-like domains of cMyPB-C (C0 and C1) interact with the TF. Results demonstrate that despite being structural homologs, C0 and C1 exhibit different patterns of binding on the surface of F-actin. Importantly, C1 but not C0 binds in a position to activate the TF by shifting tropomyosin (Tm) to the "open" structural state. We further show that C1 directly interacts with Tm and traps Tm in the open position on the surface of F-actin. Both C0 and C1 compete with myosin subfragment 1 for binding to F-actin and effectively inhibit actomyosin interactions when present at high ratios of NTDs to F-actin. Finally, we show that in contracting sarcomeres, the activating effect of C1 is apparent only once low levels of Ca(2+) have been achieved. We suggest that Ca(2+) modulates the interaction of cMyBP-C with the TF in the sarcomere.

Relationships between rodent white adipose fat pads and human white adipose fat depots

Directory of Open Access Journals (Sweden)

Daniella E. Chusyd

2016-04-01

Full Text Available The objective of this review was to compare and contrast the physiological and metabolic profiles of rodent white adipose fat pads with white adipose fat depots in humans. Human fat distribution and its metabolic consequences have received extensive attention, but much of what has been tested in translational research has relied heavily on rodents. Unfortunately, the validity of using rodent fat pads as a model of human adiposity has received less attention. There is a surprisingly lack of studies demonstrating an analogous relationship between rodent and human adiposity on obesity-related comorbidities. Therefore, we aimed to compare known similarities and disparities in terms of white adipose tissue development and distribution, sexual dimorphism, weight loss, adipokine secretion, and aging. While the literature supports the notion that many similarities exist between rodents and humans, notable differences emerge related to fat deposition and function of white adipose tissue. Thus, further research is warranted to more carefully define the strengths and limitations of rodent white adipose tissue as a model for humans, with a particular emphasis on comparable fat depots, such as mesenteric fat.

The Ethics of Rodent Control

NARCIS (Netherlands)

Meerburg, B.G.; Brom, F.W.A.; Kijlstra, A.

2008-01-01

Because western societies generally see animals as objects of moral concern, demands have been made on the way they are treated, e.g. during animal experimentation. In the case of rodent pests, however, inhumane control methods are often applied. This inconsistency in the human-animal relationship

Muscle protein analysis. II. Two-dimensional electrophoresis of normal and diseased human skeletal muscle

Energy Technology Data Exchange (ETDEWEB)

Giometti, C.S. (Argonne National Lab., IL); Barany, M.; Danon, M.J.; Anderson, N.G.

1980-07-01

High-resolution two-dimensional electrophoresis was used to analyze the major proteins of normal and pathological human-muscle samples. The normal human-muscle pattern contains four myosin light chains: three that co-migrate with the myosin light chains from rabbit fast muscle (extensor digitorum longus), and one that co-migrates with the light chain 2 from rabbit slow muscle (soleus). Of seven Duchenne muscular dystrophy samples, four yielded patterns with decreased amounts of actin and myosin relative to normal muscle, while three samples gave patterns comparable to that for normal muscle. Six samples from patients with myotonic dystrophy also gave normal patterns. In nemaline rod myopathy, in contrast, the pattern was deficient in two of the fast-type myosin light chains.

An adhesome comprising laminin, dystroglycan and myosin IIA is required during notochord development in Xenopus laevis.

Science.gov (United States)

Buisson, Nicolas; Sirour, Cathy; Moreau, Nicole; Denker, Elsa; Le Bouffant, Ronan; Goullancourt, Aline; Darribère, Thierry; Bello, Valérie

2014-12-01

Dystroglycan (Dg) is a transmembrane receptor for laminin that must be expressed at the right time and place in order to be involved in notochord morphogenesis. The function of Dg was examined in Xenopus laevis embryos by knockdown of Dg and overexpression and replacement of the endogenous Dg with a mutated form of the protein. This analysis revealed that Dg is required for correct laminin assembly, for cell polarization during mediolateral intercalation and for proper differentiation of vacuoles. Using mutations in the cytoplasmic domain, we identified two sites that are involved in cell polarization and are required for mediolateral cell intercalation, and a site that is required for vacuolation. Furthermore, using a proteomic analysis, the cytoskeletal non-muscle myosin IIA has been identified for the first time as a molecular link between the Dg-cytoplasmic domain and cortical actin. The data allowed us to identify the adhesome laminin-Dg-myosin IIA as being required to maintain the cortical actin cytoskeleton network during vacuolation, which is crucial to maintain the shape of notochordal cells. © 2014. Published by The Company of Biologists Ltd.

The water economy of South American desert rodents: from integrative to molecular physiological ecology.

Science.gov (United States)

Bozinovic, Francisco; Gallardo, Pedro

2006-01-01

Rodents from arid and semi-arid habitats live under conditions where the spatial and temporal availability of free water is limited, or scarce, thus forcing these rodents to deal with the problem of water conservation. The response of rodents to unproductive desert environments and water deficits has been intensively investigated in many deserts of the world. However, current understanding of the cellular, systemic and organismal physiology of water economy relies heavily on short-term, laboratory-oriented experiments, which usually focus on responses at isolated levels of biological organization. In addition, studies in small South American mammals are scarce. Indeed xeric habitats have existed in South America for a long time and it is intriguing why present day South American desert rodents do not show the wide array of adaptive traits to desert life observed for rodents on other continents. Several authors have pointed out that South American desert rodents lack physiological and energetic specialization for energy and water conservation, hypothesizing that their success is based more on behavioral and ecological strategies. We review phenotypic flexibility and physiological diversity in water flux rate, urine osmolality, and expression of water channels in South American desert-dwelling rodents. As far as we know, this is the first review of integrative studies at cellular, systemic and organismal levels. Our main conclusion is that South American desert rodents possess structural as well as physiological systems for water conservation, which are as remarkable as those found in "classical" rodents inhabiting other desert areas of the world.

Helminth Infections of Rodents and Their Zoonotic Importance in Boyer-Ahmad District, Southwestern Iran

Directory of Open Access Journals (Sweden)

Mohammad Javad RANJBAR

2017-12-01

Full Text Available AbstractBackground: Rodents are considered as reservoirs of various zoonotic diseases including helminthic infections. The current study aimed to evaluate the prevalence of helminth infections in rodents, in Boyer-Ahmad district, Southwestern Iran.Methods: Overall, 52 rodents were captured from various areas of the district by Sherman live traps. The animals were then euthanized and dissected. During necropsy, each organ was examined macroscopically for presence of any cyst or visible parasite. The gastrointestinal tract was removed and their contents were evaluated for larva or adult worms. Trichinella larvae in the rodents’ muscles were investigated by both digestion and pathological methods.Results: Twenty-eight (53.8% of the trapped rodents were male. The rodents were including 25 (48.1% Meriones persicus, 1(1.9% Calomyscus bailwardi, 1 (1.9% Arvicola terresterris, 7 (13.5% Rattus rattus, 8 (15.4% R. norvegicus, and 10 (19.2% Apodemus sylvaticus. Of them, 38 (73.0% were infected with at least one helminth. Collected rodents were infected with Hymenolepis diminuta (50%, Hymenolepis nana fraterna (28.8%, Skrjabinotaenia sp. (15.4%, Anoplocephalidae sp. (15.4%, Cysticercus fasciolaris (5.8%, Trichuris muris (36.5%, Aspiculuris tetraptera (15.4%, Syphacia sp. (5.7%, Rictularia sp. (15.4%, Trichostrongylus sp. (3.8%, and Gongylonema sp. (3.8%. M. persicus was the most (84% infected rodent, yet the differences between rodent genus and helminth infectivity were not statistically significant (P>0.05.Conclusion: The rodents in Boyer-Ahmad district are infected with different helminths infections that some of them are recognized as threat to human health.

Optimizing Cardiovascular Benefits of Exercise: A Review of Rodent Models

Science.gov (United States)

Davis, Brittany; Moriguchi, Takeshi; Sumpio, Bauer

2013-01-01

Although research unanimously maintains that exercise can ward off cardiovascular disease (CVD), the optimal type, duration, intensity, and combination of forms are yet not clear. In our review of existing rodent-based studies on exercise and cardiovascular health, we attempt to find the optimal forms, intensities, and durations of exercise. Using Scopus and Medline, a literature review of English language comparative journal studies of cardiovascular benefits and exercise was performed. This review examines the existing literature on rodent models of aerobic, anaerobic, and power exercise and compares the benefits of various training forms, intensities, and durations. The rodent studies reviewed in this article correlate with reports on human subjects that suggest regular aerobic exercise can improve cardiac and vascular structure and function, as well as lipid profiles, and reduce the risk of CVD. Findings demonstrate an abundance of rodent-based aerobic studies, but a lack of anaerobic and power forms of exercise, as well as comparisons of these three components of exercise. Thus, further studies must be conducted to determine a truly optimal regimen for cardiovascular health. PMID:24436579

PTP1B triggers integrin-mediated repression of myosin activity and modulates cell contractility

Directory of Open Access Journals (Sweden)

Ana E. González Wusener

2016-01-01

Full Text Available Cell contractility and migration by integrins depends on precise regulation of protein tyrosine kinase and Rho-family GTPase activities in specific spatiotemporal patterns. Here we show that protein tyrosine phosphatase PTP1B cooperates with β3 integrin to activate the Src/FAK signalling pathway which represses RhoA-myosin-dependent contractility. Using PTP1B null (KO cells and PTP1B reconstituted (WT cells, we determined that some early steps following cell adhesion to fibronectin and vitronectin occurred robustly in WT cells, including aggregation of β3 integrins and adaptor proteins, and activation of Src/FAK-dependent signalling at small puncta in a lamellipodium. However, these events were significantly impaired in KO cells. We established that cytoskeletal strain and cell contractility was highly enhanced at the periphery of KO cells compared to WT cells. Inhibition of the Src/FAK signalling pathway or expression of constitutive active RhoA in WT cells induced a KO cell phenotype. Conversely, expression of constitutive active Src or myosin inhibition in KO cells restored the WT phenotype. We propose that this novel function of PTP1B stimulates permissive conditions for adhesion and lamellipodium assembly at the protruding edge during cell spreading and migration.

PTP1B triggers integrin-mediated repression of myosin activity and modulates cell contractility

Science.gov (United States)

González Wusener, Ana E.; González, Ángela; Nakamura, Fumihiko; Arregui, Carlos O.

2016-01-01

ABSTRACT Cell contractility and migration by integrins depends on precise regulation of protein tyrosine kinase and Rho-family GTPase activities in specific spatiotemporal patterns. Here we show that protein tyrosine phosphatase PTP1B cooperates with β3 integrin to activate the Src/FAK signalling pathway which represses RhoA-myosin-dependent contractility. Using PTP1B null (KO) cells and PTP1B reconstituted (WT) cells, we determined that some early steps following cell adhesion to fibronectin and vitronectin occurred robustly in WT cells, including aggregation of β3 integrins and adaptor proteins, and activation of Src/FAK-dependent signalling at small puncta in a lamellipodium. However, these events were significantly impaired in KO cells. We established that cytoskeletal strain and cell contractility was highly enhanced at the periphery of KO cells compared to WT cells. Inhibition of the Src/FAK signalling pathway or expression of constitutive active RhoA in WT cells induced a KO cell phenotype. Conversely, expression of constitutive active Src or myosin inhibition in KO cells restored the WT phenotype. We propose that this novel function of PTP1B stimulates permissive conditions for adhesion and lamellipodium assembly at the protruding edge during cell spreading and migration. PMID:26700725

Stress, social behavior, and resilience: Insights from rodents

Science.gov (United States)

Beery, Annaliese K.; Kaufer, Daniela

2014-01-01

The neurobiology of stress and the neurobiology of social behavior are deeply intertwined. The social environment interacts with stress on almost every front: social interactions can be potent stressors; they can buffer the response to an external stressor; and social behavior often changes in response to stressful life experience. This review explores mechanistic and behavioral links between stress, anxiety, resilience, and social behavior in rodents, with particular attention to different social contexts. We consider variation between several different rodent species and make connections to research on humans and non-human primates. PMID:25562050

Research Note. Occurrence of gastrointestinal helminths in commensal rodents from Tabasco, Mexico

OpenAIRE

Cigarroa-Toledo N.; Santos-Martinez Y. De Los; Zaragoza-Vera C. V.; Garcia-Rodriguez M. M.; Baak-Baak C. M.; Machain-Williams C.; Garcia-Rejon J. E.; Panti-May J. A.; Torres-Chable O. M.

2017-01-01

The aim of this study was to determine the prevalence and species composition of helminths in commensal rodents captured inside private residences in the city of Villahermosa in Tabasco, Mexico. Trapping was performed at each house for three consecutive nights from October to December 2015. Fifty commensal rodents were captured: 23 Rattus norvegicus, 16 Mus musculus and 11 Rattus rattus. Rodents were transported alive to the laboratory and held in cages until they defecated. Feces were analyz...

Structural insights into the globular tails of the human type v myosins Myo5a, Myo5b, And Myo5c.

Directory of Open Access Journals (Sweden)

Hana Velvarska

Full Text Available Vertebrate type V myosins (MyoV Myo5a, Myo5b, and Myo5c mediate transport of several different cargoes. All MyoV paralogs bind to cargo complexes mainly by their C-terminal globular domains. In absence of cargo, the globular domain of Myo5a inhibits its motor domain. Here, we report low-resolution SAXS models for the globular domains from human Myo5a, Myo5b, and Myo5c, which suggest very similar overall shapes of all three paralogs. We determined the crystal structures of globular domains from Myo5a and Myo5b, and provide a homology model for human Myo5c. When we docked the Myo5a crystal structure into a previously published electron microscopy density of the autoinhibited full-length Myo5a, only one domain orientation resulted in a good fit. This structural arrangement suggests the participation of additional region of the globular domain in autoinhibition. Quantification of the interaction of the Myo5a globular domain with its motor complex revealed a tight binding with dissociation half-life in the order of minutes, suggesting a rather slow transition between the active and inactive states.

Myosin dephosphorylation during rapid relaxation of hog carotid artery smooth muscle.

Science.gov (United States)

Driska, S P; Stein, P G; Porter, R

1989-02-01

Changes in myosin light chain phosphorylation were measured during histamine-induced rhythmic contractions of hog carotid artery smooth muscle strips. Histamine made the muscle strips contract spontaneously every 1-5 min, and this allowed measurement of the time course of phosphorylation in relation to force development under conditions where diffusion of the agonist through tissue would not complicate the interpretation of the data. In the absence of histamine, phosphorylation was low [0.12 +/- 0.04 mol P/mol of the 20,000-Da light chain (LC 20)]. Phosphorylation was slightly (but not significantly) higher in the presence of 10 microM histamine in the relaxed state between contractions (0.20 +/- 0.03 mol P/mol LC 20). In muscle strips frozen during force development, when force had reached half of its peak value, phosphorylation was 0.38 +/- 0.06 mol P/mol LC 20. The highest levels of phosphorylation (0.49 +/- 0.04 mol P/mol LC 20) were found in strips frozen at the peak of the rhythmic contractions. Strips frozen when force had declined to half of the peak force showed low levels of phosphorylation (0.17 +/- 0.07 mol P/mol LC 20), indicating that the myosin light chain phosphatase activity was quite high. Mathematical modeling of the kinase and phosphatase reactions suggested that the apparent first-order phosphatase rate constant was at least 0.08 s-1 under these conditions. To obtain a better estimate of this rate constant, a second series of phosphorylation measurements were made early in the relaxation phase of the rhythmic contractions. The highest phosphatase rate constant obtained from these measurements was 0.23 s-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction between cardiac myosin-binding protein C and formin Fhod3.

Science.gov (United States)

Matsuyama, Sho; Kage, Yohko; Fujimoto, Noriko; Ushijima, Tomoki; Tsuruda, Toshihiro; Kitamura, Kazuo; Shiose, Akira; Asada, Yujiro; Sumimoto, Hideki; Takeya, Ryu

2018-05-08

Mutations in cardiac myosin-binding protein C (cMyBP-C) are a major cause of familial hypertrophic cardiomyopathy. Although cMyBP-C has been considered to regulate the cardiac function via cross-bridge arrangement at the C-zone of the myosin-containing A-band, the mechanism by which cMyBP-C functions remains unclear. We identified formin Fhod3, an actin organizer essential for the formation and maintenance of cardiac sarcomeres, as a cMyBP-C-binding protein. The cardiac-specific N-terminal Ig-like domain of cMyBP-C directly interacts with the cardiac-specific N-terminal region of Fhod3. The interaction seems to direct the localization of Fhod3 to the C-zone, since a noncardiac Fhod3 variant lacking the cMyBP-C-binding region failed to localize to the C-zone. Conversely, the cardiac variant of Fhod3 failed to localize to the C-zone in the cMyBP-C-null mice, which display a phenotype of hypertrophic cardiomyopathy. The cardiomyopathic phenotype of cMyBP-C-null mice was further exacerbated by Fhod3 overexpression with a defect of sarcomere integrity, whereas that was partially ameliorated by a reduction in the Fhod3 protein levels, suggesting that Fhod3 has a deleterious effect on cardiac function under cMyBP-C-null conditions where Fhod3 is aberrantly mislocalized. Together, these findings suggest the possibility that Fhod3 contributes to the pathogenesis of cMyBP-C-related cardiomyopathy and that Fhod3 is critically involved in cMyBP-C-mediated regulation of cardiac function via direct interaction.

A fast-slow logic system

International Nuclear Information System (INIS)

Kawashima, Hideo.

1977-01-01

A fast-slow logic system has been made for use in multi-detector experiments in nuclear physics such as particle-gamma and particle-particle coincidence experiments. The system consists of a fast logic system and a slow logic system. The fast logic system has a function of fast coincidences and provides timing signals for the slow logic system. The slow logic system has a function of slow coincidences and a routing control of input analog signals to the ADCs. (auth.)

Comparison of food hoarding of two sympatric rodent species under interspecific competition.

Science.gov (United States)

Zhang, Yi-Feng; Tong, Lei; Ji, Wei-Hong; Lu, Ji-Qi

2013-01-01

Competition can greatly affect the food hoarding strategies of rodents and the fate of seeds hoarded. In order to understand the influence of interspecific competition on food caching behavior of sympatric rodents, we investigated food hoarding patterns of two sympatric rodent species, buff-breasted rat (Rattus flavipectus) and Chinese white-bellied rat (Niviventor confucianus), and compared their responses and adjustment in hoarding behavior under interspecific competition. The results showed that: (1) the buff-breasted rat larder hoarded seeds only, while Chinese white-bellied rat hoarded seeds in both larder and scatter forms; (2) two species of rodents both larder hoarded more seeds when competitors were present; and (3) the Chinese white-bellied rats adjusted their seed hoarding from scatter to larder when competitors were introduced, which reduced the seed availability. Therefore, we concluded that rodents would adjust their food hoarding strategy when interspecific competitors were present, and this may produce a different effect on the fate of seeds and the recruitment of plants. This article is part of a Special Issue entitled: insert SI title. Copyright © 2012. Published by Elsevier B.V.

Tick parasites of rodents in Romania: host preferences, community structure and geographical distribution.

Science.gov (United States)

Mihalca, Andrei D; Dumitrache, Mirabela O; Sándor, Attila D; Magdaş, Cristian; Oltean, Miruna; Györke, Adriana; Matei, Ioana A; Ionică, Angela; D'Amico, Gianluca; Cozma, Vasile; Gherman, Călin M

2012-11-21

Ticks are among the most important vectors of zoonotic diseases in temperate regions of Europe, with widespread distribution and high densities, posing an important medical risk. Most ticks feed on a variety of progressively larger hosts, with a large number of small mammal species typically harbouring primarily the immature stages. However, there are certain Ixodidae that characteristically attack micromammals also during their adult stage. Rodents are widespread hosts of ticks, important vectors and competent reservoirs of tick-borne pathogens. Micromammal-tick associations have been poorly studied in Romania, and our manuscript shows the results of a large scale study on tick infestation epidemiology in rodents from Romania. Rodents were caught using snap-traps in a variety of habitats in Romania, between May 2010 and November 2011. Ticks were individually collected from these rodents and identified to species and development stage. Frequency, mean intensity, prevalence and its 95% confidence intervals were calculated using the EpiInfo 2000 software. A p value of Romania for the presence of ticks. Each collected tick was identified to species level and the following epidemiological parameters were calculated: prevalence, mean intensity and mean abundance. The total number of ticks collected from rodents was 483, with eight species identified: Ixodes ricinus, I. redikorzevi, I. apronophorus, I. trianguliceps, I. laguri, Dermacentor marginatus, Rhipicephalus sanguineus and Haemaphysalis sulcata. The overall prevalence of tick infestation was 29.55%, with a mean intensity of 3.86 and a mean abundance of 1.14. Only two polyspecific infestations were found: I. ricinus + I. redikorzevi and I. ricinus + D. marginatus. Our study showed a relatively high diversity of ticks parasitizing rodents in Romania. The most common tick in rodents was I. ricinus, followed by I. redikorzevi. Certain rodents seem to host a significantly higher number of tick species than others, the

The need to implement the landscape of fear within rodent pest management strategies.

Science.gov (United States)

Krijger, Inge M; Belmain, Steven R; Singleton, Grant R; Groot Koerkamp, Peter Wg; Meerburg, Bastiaan G

2017-12-01

Current reactive pest management methods have serious drawbacks such as the heavy reliance on chemicals, emerging genetic rodenticide resistance and high secondary exposure risks. Rodent control needs to be based on pest species ecology and ethology to facilitate the development of ecologically based rodent management (EBRM). An important aspect of EBRM is a strong understanding of rodent pest species ecology, behaviour and spatiotemporal factors. Gaining insight into the behaviour of pest species is a key aspect of EBRM. The landscape of fear (LOF) is a mapping of the spatial variation in the foraging cost arising from the risk of predation, and reflects the levels of fear a prey species perceives at different locations within its home range. In practice, the LOF maps habitat use as a result of perceived fear, which shows where bait or traps are most likely to be encountered and used by rodents. Several studies have linked perceived predation risk of foraging animals with quitting-harvest rates or giving-up densities (GUDs). GUDs have been used to reflect foraging behaviour strategies of predator avoidance, but to our knowledge very few papers have directly used GUDs in relation to pest management strategies. An opportunity for rodent control strategies lies in the integration of the LOF of rodents in EBRM methodologies. Rodent management could be more efficient and effective by concentrating on those areas where rodents perceive the least levels of predation risk. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Human faces are slower than chimpanzee faces.

Directory of Open Access Journals (Sweden)

Anne M Burrows

Full Text Available While humans (like other primates communicate with facial expressions, the evolution of speech added a new function to the facial muscles (facial expression muscles. The evolution of speech required the development of a coordinated action between visual (movement of the lips and auditory signals in a rhythmic fashion to produce "visemes" (visual movements of the lips that correspond to specific sounds. Visemes depend upon facial muscles to regulate shape of the lips, which themselves act as speech articulators. This movement necessitates a more controlled, sustained muscle contraction than that produced during spontaneous facial expressions which occur rapidly and last only a short period of time. Recently, it was found that human tongue musculature contains a higher proportion of slow-twitch myosin fibers than in rhesus macaques, which is related to the slower, more controlled movements of the human tongue in the production of speech. Are there similar unique, evolutionary physiologic biases found in human facial musculature related to the evolution of speech?Using myosin immunohistochemistry, we tested the hypothesis that human facial musculature has a higher percentage of slow-twitch myosin fibers relative to chimpanzees (Pan troglodytes and rhesus macaques (Macaca mulatta. We sampled the orbicularis oris and zygomaticus major muscles from three cadavers of each species and compared proportions of fiber-types. Results confirmed our hypothesis: humans had the highest proportion of slow-twitch myosin fibers while chimpanzees had the highest proportion of fast-twitch fibers.These findings demonstrate that the human face is slower than that of rhesus macaques and our closest living relative, the chimpanzee. They also support the assertion that human facial musculature and speech co-evolved. Further, these results suggest a unique set of evolutionary selective pressures on human facial musculature to slow down while the function of this muscle

Zoonotic pathogens in Atlantic Forest wild rodents in Brazil: Bartonella and Coxiella infections.

Science.gov (United States)

Rozental, Tatiana; Ferreira, Michelle Santos; Guterres, Alexandro; Mares-Guia, Maria Angélica; Teixeira, Bernardo R; Gonçalves, Jonathan; Bonvicino, Cibele Rodrigues; D'Andrea, Paulo Sergio; de Lemos, Elba Regina Sampaio

2017-04-01

Zoonotic pathogens comprise a significant and increasing fraction of all emerging and re-emerging infectious diseases that plague humans. Identifying host species is one of the keys to controlling emerging infectious diseases. From March 2007 until April 2012, we collected a total of 131 wild rodents in eight municipalities of Rio de Janeiro, Brazil. We investigated these rodents for infection with Coxiella burnetii, Bartonella spp. and Rickettsia spp. In total, 22.1% (29/131) of the rodents were infected by at least one pathogen; co-infection was detected in 1.5% (2/131) of rodents. Coxiella burnetii was detected in 4.6% (6/131) of the wild animals, 17.6% of the rodents harbored Bartonella spp. No cases of Rickettsia were identified. Bartonella doshiae and Bartonella vinsonii were the species found on the wild mammals. This report is the first to note C. burnetii, B. doshiae and B. vinsonii natural infections in Atlantic Forest wild rodents in Brazil. Our work highlights the potential risk of transmission to humans, since most of the infected specimens belong to generalist species that live near human dwellings. Copyright © 2017 Elsevier B.V. All rights reserved.

Neurogenetics of aggressive behavior: studies in rodents.

Science.gov (United States)

Takahashi, Aki; Miczek, Klaus A

2014-01-01

Aggressive behavior is observed in many animal species, such as insects, fish, lizards, frogs, and most mammals including humans. This wide range of conservation underscores the importance of aggressive behavior in the animals' survival and fitness, and the likely heritability of this behavior. Although typical patterns of aggressive behavior differ between species, there are several concordances in the neurobiology of aggression among rodents, primates, and humans. Studies with rodent models may eventually help us to understand the neurogenetic architecture of aggression in humans. However, it is important to recognize the difference between the ecological and ethological significance of aggressive behavior (species-typical aggression) and maladaptive violence (escalated aggression) when applying the findings of aggression research using animal models to human or veterinary medicine. Well-studied rodent models for aggressive behavior in the laboratory setting include the mouse (Mus musculus), rat (Rattus norvegicus), hamster (Mesocricetus auratus), and prairie vole (Microtus ochrogaster). The neural circuits of rodent aggression have been gradually elucidated by several techniques, e.g., immunohistochemistry of immediate-early gene (c-Fos) expression, intracranial drug microinjection, in vivo microdialysis, and optogenetics techniques. Also, evidence accumulated from the analysis of gene-knockout mice shows the involvement of several genes in aggression. Here, we review the brain circuits that have been implicated in aggression, such as the hypothalamus, prefrontal cortex (PFC), dorsal raphe nucleus (DRN), nucleus accumbens (NAc), and olfactory system. We then discuss the roles of glutamate and γ-aminobutyric acid (GABA), excitatory and inhibitory amino acids in the brain, as well as their receptors, in controlling aggressive behavior, focusing mainly on recent findings. At the end of this chapter, we discuss how genes can be identified that underlie individual

The influence of temperature on the distribution and intensity of the reaction product in rat muscle fibers obtained with the histochemical method for myosin ATPase

DEFF Research Database (Denmark)

Kirkeby, S; Tuxen, A

1989-01-01

The influence of temperature in the incubation medium on the localization and intensity of myosin ATPase was investigated in striated muscles from the rat using a conventional histochemical technique. It was found that the enzyme reaction was temperature-dependent since the activity in some fibers...... was raised and in others was depressed by alteration of the incubation temperature. There was no obvious correlation between the temperature sensitivity of ATPase in the muscle fibers and their activity for succinic dehydrogenase. It is proposed that the histochemical method for myosin ATPase can be used...

Very slow neutrons

International Nuclear Information System (INIS)

Frank, A.

1983-01-01

The history is briefly presented of the research so far of very slow neutrons and their basic properties are explained. The methods are described of obtaining very slow neutrons and the problems of their preservation are discussed. The existence of very slow neutrons makes it possible to perform experiments which may deepen the knowledge of the fundamental properties of neutrons. Their wavelength approximates that of visible radiation. The possibilities and use are discussed of neutron optical systems (neutron microscope) which could be an effective instrument for the study of the detailed arrangement, especially of organic substances. (B.S.)

The valproic acid-induced rodent model of autism.

Science.gov (United States)

Nicolini, Chiara; Fahnestock, Margaret

2018-01-01

Autism is a lifelong neurodevelopmental disorder characterized by impairments in social communication and interaction and by repetitive patterns of behavior, interests and activities. While autism has a strong genetic component, environmental factors including toxins, pesticides, infection and drugs are known to confer autism susceptibility, likely by inducing epigenetic changes. In particular, exposure to valproic acid (VPA) during pregnancy has been demonstrated to increase the risk of autism in children. Furthermore, rodents prenatally exposed to this drug display behavioral phenotypes characteristics of the human condition. Indeed, in utero exposure of rodents to VPA represents a robust model of autism exhibiting face, construct and predictive validity. This model might better represent the many cases of idiopathic autism which are of environmental/epigenetic origins than do transgenic models carrying mutations in single autism-associated genes. The VPA model provides a valuable tool to investigate the neurobiology underlying autistic behavior and to screen for novel therapeutics. Here we review the VPA-induced rodent model of autism, highlighting its importance and reliability as an environmentally-induced animal model of autism. Copyright © 2017 Elsevier Inc. All rights reserved.

The unappreciated slowness of conventional tourism

Directory of Open Access Journals (Sweden)

G.R. Larsen

2016-05-01

Full Text Available Most tourists are not consciously engaging in ‘slow travel’, but a number of travel behaviours displayed by conventional tourists can be interpreted as slow travel behaviour. Based on Danish tourists’ engagement with the distances they travel across to reach their holiday destination, this paper explores unintended slow travel behaviours displayed by these tourists. None of the tourists participating in this research were consciously doing ‘slow travel’, and yet some of their most valued holiday memories are linked to slow travel behaviours. Based on the analysis of these unintended slow travel behaviours, this paper will discuss the potential this insight might hold for promotion of slow travel. If unappreciated and unintentional slow travel behaviours could be utilised in the deliberate effort of encouraging more people to travel slow, ‘slow travel’ will be in a better position to become integrated into conventional travel behaviour.

Guide to Commensal Rodent Control

Science.gov (United States)

1991-12-01

in many detergents also fluoresce. For positive identification, place the suspect material on Urease Siom lhymol Blue test paper, moisten with water...are applied in a thin layer in protected rat and mouse r’unways, baitboxes, or tubes along walls. The powder is picked up by the rodents on their feet

Occurrence and distribution of Giardia species in wild rodents in Germany.

Science.gov (United States)

Helmy, Yosra A; Spierling, Nastasja G; Schmidt, Sabrina; Rosenfeld, Ulrike M; Reil, Daniela; Imholt, Christian; Jacob, Jens; Ulrich, Rainer G; Aebischer, Toni; Klotz, Christian

2018-03-27

Giardiasis is an important gastrointestinal parasitic disease in humans and other mammals caused by the protozoan Giardia duodenalis. This species complex is represented by genetically distinct groups (assemblages A-H) with varying zoonotic potential and host preferences. Wild rodents can harbor potentially zoonotic assemblages A and B, and the rodent-specific assemblage G. Other Giardia spp. found in these animals are Giardia muris and Giardia microti. For the latter, only limited information on genetic typing is available. It has been speculated that wild rodents might represent an important reservoir for parasites causing human giardiasis. The aim of this study was to investigate the occurrence and distribution of Giardia spp. and assemblage types in wild rodents from different study sites in Germany. Screening of 577 wild rodents of the genera Apodemus, Microtus and Myodes, sampled at eleven study sites in Germany, revealed a high overall Giardia prevalence. Giardia species determination at the SSU rDNA gene locus revealed that Apodemus mice, depending on species, were predominantly infected with one of two distinct G. muris sequence types. Giardia microti was the predominant parasite species found in voles of the genera Microtus and Myodes. Only a few animals were positive for potentially zoonotic G. duodenalis. Subtyping at the beta-giardin (bg) and glutamine dehydrogenase (gdh) genes strongly supported the existence of different phylogenetic subgroups of G. microti that are preferentially harbored by distinct host species. The present study highlights the preference of G. muris for Apodemus, and G. microti for Microtus and Myodes hosts and argues for a very low prevalence of zoonotic G. duodenalis assemblages in wild rodents in Germany. It also provides evidence that G. muris and G. microti subdivide into several phylogenetically distinguishable subgroups, each of which appears to be preferentially harbored by species of a particular rodent host genus

The bioeconomics of controlling an African rodent pest species

OpenAIRE

Skonhoft, Anders; Herwig, Leirs; Andreassen, Harry Peter; Mulungu, Loth S. A.; Stenseth, Nils Christian

2006-01-01

The paper treats the economy of controlling an African pest rodent, the multimammate rat, causing major damage in maize production. An ecological population model is presented and used as a basis for the economic analyses carried out at the village level using data from Tanzania. This model incorporates both density-dependent and density-independent (stochastic) factors. Rodents are controlled by applying poison, and the economic benefits depend on the income from maize production minus the c...

Domestic cats and dogs create a landscape of fear for pest rodents around rural homesteads.

Directory of Open Access Journals (Sweden)

Themb'alilahlwa A M Mahlaba

Full Text Available Using domestic predators such as cats to control rodent pest problems around farms and homesteads is common across the world. However, practical scientific evidence on the impact of such biological control in agricultural settings is often lacking. We tested whether the presence of domestic cats and/or dogs in rural homesteads would affect the foraging behaviour of pest rodents. We estimated giving up densities (GUDs from established feeding patches and estimated relative rodent activity using tracking tiles at 40 homesteads across four agricultural communities. We found that the presence of cats and dogs at the same homestead significantly reduced activity and increased GUDs (i.e. increased perception of foraging cost of pest rodent species. However, if only cats or dogs alone were present at the homestead there was no observed difference in rodent foraging activity in comparison to homesteads with no cats or dogs. Our results suggest that pest rodent activity can be discouraged through the presence of domestic predators. When different types of predator are present together they likely create a heightened landscape of fear for foraging rodents.

Planar polarization of Vangl2 in the vertebrate neural plate is controlled by Wnt and Myosin II signaling

Directory of Open Access Journals (Sweden)

Olga Ossipova

2015-07-01

Full Text Available The vertebrate neural tube forms as a result of complex morphogenetic movements, which require the functions of several core planar cell polarity (PCP proteins, including Vangl2 and Prickle. Despite the importance of these proteins for neurulation, their subcellular localization and the mode of action have remained largely unknown. Here we describe the anteroposterior planar cell polarity (AP-PCP of the cells in the Xenopus neural plate. At the neural midline, the Vangl2 protein is enriched at anterior cell edges and that this localization is directed by Prickle, a Vangl2-interacting protein. Our further analysis is consistent with the model, in which Vangl2 AP-PCP is established in the neural plate as a consequence of Wnt-dependent phosphorylation. Additionally, we uncover feedback regulation of Vangl2 polarity by Myosin II, reiterating a role for mechanical forces in PCP. These observations indicate that both Wnt signaling and Myosin II activity regulate cell polarity and cell behaviors during vertebrate neurulation.

Protozoan Parasites of Rodents and Their Zoonotic Significance in Boyer-Ahmad District, Southwestern Iran

Directory of Open Access Journals (Sweden)

Zeinab Seifollahi

2016-01-01

Full Text Available Backgrounds. Wild rodents are reservoirs of various zoonotic diseases, such as toxoplasmosis, babesiosis, and leishmaniasis. The current study aimed to assess the protozoan infection of rodents in Boyer-Ahmad district, southwestern Iran. Materials and Methods. A total of 52 rodents were collected from different parts of Boyer-Ahmad district, in Kohgiluyeh and Boyer-Ahmad province, using Sherman live traps. Each rodent was anesthetized with ether, according to the ethics of working with animals, and was dissected. Samples were taken from various tissues and stool samples were collected from the contents of the colon and small intestines. Moreover, 2 to 5 mL of blood was taken from each of the rodents and the sera were examined for anti-Leishmania antibodies, by ELISA, or anti-T. gondii antibodies, by modified agglutination test (MAT. DNA was extracted from brain tissue samples of each rodent and PCR was used to identify the DNA of T. gondii. Results. Of the 52 stool samples of rodents studied by parasitological methods, intestinal protozoa infection was seen in 28 cases (53.8%. From 52 rodents, 19 (36.5% were infected with Trichomonas, 10 (19.2% with Giardia muris, and 11 (21.2% with Entamoeba spp. Also, 10 cases (19.2% were infected with Blastocystis, 3 (5.8% were infected with Chilomastix, 7 (13.5% were infected with Endolimax, 1 (1.9% was infected with Retortamonas, 3 (5.77% were infected with T. gondii, and 6 (11.54% were infected with Trypanosoma lewisi. Antibodies to T. gondii were detected in the sera of 5 (9.61% cases. Results of the molecular study showed T. gondii infection in 3 (5.77% of the rodents. Findings of this study showed that rodents in Kohgiluyeh and Boyer-Ahmad province, southwestern Iran, are infected with several blood and intestinal parasites; some of them might be potential risks to residents and domestic animals in the region.

Population response of rodents to control with rodenticides

Directory of Open Access Journals (Sweden)

A.V. TCHABOVSKY

2009-04-01

Full Text Available We summarize theoretical approaches and practice of rodent pest control in Russia and former USSR during last 50 years. We review literature as well as original data to understand mechanisms of rodent populations recovery after chemical control campaigns in urban areas, agricultural lands and natural foci of plague. Laboratory and field experiments indicate that inherent individual variation in behavioural, physiological and life-history traits provides survival of heterogeneous mix of individuals in residual population with increased resistance to poisonous baits and high reproductive potential that leads to fast recovery of a population. In a series of field experiments with various rodent and lagomorph species (Mus musculus, Rattus norvegicus, Meriones unguiculatus, M.meridianus, M.tamariscinus, Ochotona pallasii we have shown that patterns of recolonization of depopulated area and mechanisms of population recovery vary among species and depend on species-specific social organization. After control territorial and group-living species demonstrated an increase in mobility and affiliative and marking behaviour and a decrease in intraspecific aggression. The rate of recolonization of treated areas was high due to redistribution of survived individuals and immigration by neighbors. Population recovered to original level due to increased breeding performance and fecundity of both survived residents and immigrants. In contrast, socially-independent species exhibited minor changes in behaviour. Recolonization was mainly due to better survival and recruitment of youngs, so the rate of recolonization was low. Species-specificity of behavioural compensation mechanisms to control should be considered when developing ecologically based rodent management strategies.

an ecological study on rodents of natural vegetation and farm lands ...

African Journals Online (AJOL)

preferred customer

habitat association of rodents was conducted in Siltie natural vegetation and nearby farmlands ... In each habitat type, one representative grid was selected for live trapping. In addition, rodents were also snap- trapped from these habitats. A total of 562 captures was made .... into seeds, leaves, roots, earthworms and arthro-.

Small rodents as paratenic or intermediate hosts of carnivore parasites in Berlin, Germany.

Science.gov (United States)

Krücken, Jürgen; Blümke, Julia; Maaz, Denny; Demeler, Janina; Ramünke, Sabrina; Antolová, Daniela; Schaper, Roland; von Samson-Himmelstjerna, Georg

2017-01-01

Rodents are important intermediate and paratenic hosts for carnivore parasites, including the important zoonotic agents Toxoplasma, Echinococcus and Toxocara. Monitoring of such parasites in rodents can be used to detect increasing risks for human and veterinary public health. Rodents were trapped at four sites in Berlin, two near the city center, two at the periphery. PCRs were conducted to detect Coccidia (target ITS-1) and specifically Toxoplasma gondii (repetitive element) in brain and ascarids (ITS-2) in muscle or brain tissue. During necropsies, metacestodes were collected and identified using ITS-2 and 12S rRNA PCRs. An ELISA to detect antibodies against Toxocara canis ES antigens was performed. Within the 257 examined rodents, the most frequently observed parasite was Frenkelia glareoli predominantly found in Myodes glareolus. T. gondii was only detected in 12 rodents and Microtus spp. (although strongly underrepresented) had a significantly increased chance of being positive. Neither Echinococcus nor typical Taenia parasites of dogs and cats were found but Mesocestoides litteratus and Taenia martis metacestodes were identified which can cause severe peritoneal or ocular cysticercosis in dogs, primates and humans. Using PCR, the ascarids T. canis (n = 8), Toxocara cati (4) and Parascaris sp. (1) were detected predominantly in muscles. Seroprevalence of T. canis was 14.2% and ELISA was thus more sensitive than PCR to detect infection with this parasite. Non-parametric multidimensional scaling and cluster analysis revealed that parasite communities could be grouped into an urban and a peri-urban cluster with high frequency of ascarid-positive rodents in urban and high frequency of F. glareoli in peri-urban sites. Prevalence rates of parasites in rodents with potential impact for human or veterinary public health are considerable and the monitoring of transmission cycles of carnivore parasites in intermediate rodent hosts is recommended to estimate the health

Small rodents as paratenic or intermediate hosts of carnivore parasites in Berlin, Germany.

Directory of Open Access Journals (Sweden)

Jürgen Krücken

Full Text Available Rodents are important intermediate and paratenic hosts for carnivore parasites, including the important zoonotic agents Toxoplasma, Echinococcus and Toxocara. Monitoring of such parasites in rodents can be used to detect increasing risks for human and veterinary public health. Rodents were trapped at four sites in Berlin, two near the city center, two at the periphery. PCRs were conducted to detect Coccidia (target ITS-1 and specifically Toxoplasma gondii (repetitive element in brain and ascarids (ITS-2 in muscle or brain tissue. During necropsies, metacestodes were collected and identified using ITS-2 and 12S rRNA PCRs. An ELISA to detect antibodies against Toxocara canis ES antigens was performed. Within the 257 examined rodents, the most frequently observed parasite was Frenkelia glareoli predominantly found in Myodes glareolus. T. gondii was only detected in 12 rodents and Microtus spp. (although strongly underrepresented had a significantly increased chance of being positive. Neither Echinococcus nor typical Taenia parasites of dogs and cats were found but Mesocestoides litteratus and Taenia martis metacestodes were identified which can cause severe peritoneal or ocular cysticercosis in dogs, primates and humans. Using PCR, the ascarids T. canis (n = 8, Toxocara cati (4 and Parascaris sp. (1 were detected predominantly in muscles. Seroprevalence of T. canis was 14.2% and ELISA was thus more sensitive than PCR to detect infection with this parasite. Non-parametric multidimensional scaling and cluster analysis revealed that parasite communities could be grouped into an urban and a peri-urban cluster with high frequency of ascarid-positive rodents in urban and high frequency of F. glareoli in peri-urban sites. Prevalence rates of parasites in rodents with potential impact for human or veterinary public health are considerable and the monitoring of transmission cycles of carnivore parasites in intermediate rodent hosts is recommended to

Human Masseter Muscle Fibers From the Elderly Express Less Neonatal Myosin Than Those of Young Adults

Czech Academy of Sciences Publication Activity Database

Cvetko, E.; Karen, Petr; Janáček, Jiří; Kubínová, Lucie; Plasencia, A.L.; Eržen, I.

2012-01-01

Roč. 295, č. 8 (2012), s. 1364-1372 ISSN 1932-8486 R&D Projects: GA MŠk(CZ) LC06063; GA MŠk(CZ) MEB090910 Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : aging * confocal microscopy * myosin heavy chain * immunohistochemistry * muscle fiber types Subject RIV: FH - Neurology Impact factor: 1.343, year: 2012

Bulkiness or aromatic nature of tyrosine-143 of actin is important for the weak binding between F-actin and myosin-ADP-phosphate

Energy Technology Data Exchange (ETDEWEB)

Gomibuchi, Yuki [Graduate School of Science and Engineering, Teikyo University, Toyosatodai 1-1, Utsunomiya 320-8551 (Japan); Uyeda, Taro Q.P. [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Wakabayashi, Takeyuki, E-mail: tw007@nasu.bio.teikyo-u.ac.jp [Graduate School of Science and Engineering, Teikyo University, Toyosatodai 1-1, Utsunomiya 320-8551 (Japan); Department of Judo Therapy, Faculty of Medical Technology, Teikyo University, Toyosatodai 1-1, Utsunomiya 320-8551 (Japan)

2013-11-29

Highlights: •The effect of mutation of Tyr143 that becomes more exposed on assembly was examined. •Mutation of tyrosine-143 of Dictyostelium actin changed actin polymerizability. •The bulkiness or aromatic nature of Tyr143 is important for the weak binding. •The weak interaction between myosin and actin strengthened by Tyr143Trp mutation. -- Abstract: Actin filaments (F-actin) interact with myosin and activate its ATPase to support force generation. By comparing crystal structures of G-actin and the quasi-atomic model of F-actin based on high-resolution cryo-electron microscopy, the tyrosine-143 was found to be exposed more than 60 Å{sup 2} to the solvent in F-actin. Because tyrosine-143 flanks the hydrophobic cleft near the hydrophobic helix that binds to myosin, the mutant actins, of which the tyrosine-143 was replaced with tryptophan, phenylalanine, or isoleucine, were generated using the Dictyostelium expression system. It polymerized significantly poorly when induced by NaCl, but almost normally by KCl. In the presence of phalloidin and KCl, the extents of the polymerization of all the mutant actins were comparable to that of the wild-type actin so that the actin-activated myosin ATPase activity could be reliably compared. The affinity of skeletal heavy meromyosin to F-actin and the maximum ATPase activity (V{sub max}) were estimated by a double reciprocal plot. The Tyr143Trp-actin showed the higher affinity (smaller K{sub app}) than that of the wild-type actin, with the V{sub max} being almost unchanged. The K{sub app} and V{sub max} of the Tyr143Phe-actin were similar to those of the wild-type actin. However, the activation by Tyr143Ile-actin was much smaller than the wild-type actin and the accurate determination of K{sub app} was difficult. Comparison of the myosin ATPase activated by the various mutant actins at the same concentration of F-actin showed that the extent of activation correlates well with the solvent-accessible surface areas (ASA

Prevalence and genetic diversity of Bartonella strains in rodents from northwestern Mexico.

Science.gov (United States)

Rubio, André V; Ávila-Flores, Rafael; Osikowicz, Lynn M; Bai, Ying; Suzán, Gerardo; Kosoy, Michael Y

2014-12-01

Bartonella infections were investigated in wild rodents from northwestern Chihuahua, Mexico. A total of 489 rodents belonging to 14 species were surveyed in four areas. Bartonella bacteria were cultured from 50.1% of rodent samples (245/489). Infection rates ranged from 0% to 83.3% per rodent species, with no significant difference between sites except for Cynomys ludovicianus. Phylogenetic analyses of the citrate synthase gene (gltA) of the Bartonella isolates revealed 23 genetic variants (15 novel and 8 previously described), clustering into five phylogroups. Three phylogroups were associated with Bartonella vinsonii subsp. vinsonii, B. vinsonii subsp. arupensis, and B. washoensis, respectively. The other two phylogroups were not genetically related to any known Bartonella species. The genetic variants and phylogenetic groups exhibited a high degree of host specificity, mainly at the genus and family levels. This is the first study that describes the genetic diversity of Bartonella strains in wild rodents from Mexico. Considering that some variants found in this study are associated with Bartonella species that have been reported as zoonotic, more investigations are needed to further understand the ecology of Bartonella species in Mexican wildlife and their implications for human health.

Synanthropic rodents as possible reservoirs of shigatoxigenic Escherichia coli strains

Directory of Open Access Journals (Sweden)

Ximena eBlanco Crivelli

2012-11-01

Full Text Available Shigatoxigenic Escherichia coli (STEC strains are worldwide zoonotic pathogen responsible for different cases of human disease including hemolytic uremic syndrome (HUS. Transmission of STEC to humans occurs through the consumption of food and water contaminated by faeces of carriers and by person-to-person contact.The objective of this study was twofold: (a to investigate whether synanthropic rodents are possible reservoirs of STEC in the urban area and (b whether a particular genus out of synanthropic rodent is the principal carrier of STEC.One hundred forty-five rodents were captured in Buenos Aires City. Screening for stx1/stx2 and rfbO157 was done by PCR from the confluence zone. STEC isolates were further characterized with biochemical tests by standard methods. Additional virulence factors (eae, ehxA and saa were also determined by PCR. Forty-one of the rodents were necropsied and sample of kidney and small and large intestine were taken for histopathological diagnosis. The samples sections were stained with hematoxylin-eosin, and observed by light microscopy to evaluate the systemic involvement of these species in natural infections. STEC was isolated from seven out of twenty seven suspect animals at screening. The following genotypes were found in the STEC strains: stx1/stx2/ehxA (1, stx2 (4, stx2/ehxA (1, stx2/ehxA/eae (1. Neither gross nor microscopic lesions compatible with those produced by Shiga toxin were observed in the studied organs of necropsied rodents.The bivariate analysis including the hundred forty-five rodents data showed that the isolation of STEC is associated positively to Rattus genus. This synanthropic species may play a role in the transmissibility of the agent thus being a risk to the susceptible population. Their control should be included specifically in actions to dismiss the contamination of food and water by STEC in the urban area, as additional strategies for epidemiological control.

β-Arrestin regulation of myosin light chain phosphorylation promotes AT1aR-mediated cell contraction and migration.

Directory of Open Access Journals (Sweden)

Elie Simard

Full Text Available Over the last decade, it has been established that G-protein-coupled receptors (GPCRs signal not only through canonical G-protein-mediated mechanisms, but also through the ubiquitous cellular scaffolds β-arrestin-1 and β-arrestin-2. Previous studies have implicated β-arrestins as regulators of actin reorganization in response to GPCR stimulation while also being required for membrane protrusion events that accompany cellular motility. One of the most critical events in the active movement of cells is the cyclic phosphorylation and activation of myosin light chain (MLC, which is required for cellular contraction and movement. We have identified the myosin light chain phosphatase Targeting Subunit (MYPT-1 as a binding partner of the β-arrestins and found that β-arrestins play a role in regulating the turnover of phosphorylated myosin light chain. In response to stimulation of the angiotensin Type 1a Receptor (AT1aR, MLC phosphorylation is induced quickly and potently. We have found that β-arrestin-2 facilitates dephosphorylation of MLC, while, in a reciprocal fashion, β-arrestin 1 limits dephosphorylation of MLC. Intriguingly, loss of either β-arrestin-1 or 2 blocks phospho-MLC turnover and causes a decrease in the contraction of cells as monitored by atomic force microscopy (AFM. Furthermore, by employing the β-arrestin biased ligand [Sar(1,Ile(4,Ile(8]-Ang, we demonstrate that AT1aR-mediated cellular motility involves a β-arrestin dependent component. This suggests that the reciprocal regulation of MLC phosphorylation status by β-arrestins-1 and 2 causes turnover in the phosphorylation status of MLC that is required for cell contractility and subsequent chemotaxic motility.

Movement - uncontrolled or slow

Science.gov (United States)

Dystonia; Involuntary slow and twisting movements; Choreoathetosis; Leg and arm movements - uncontrollable; Arm and leg movements - uncontrollable; Slow involuntary movements of large muscle groups; Athetoid movements

BEHAVIOURAL STUDIES ON SOME RHODESIAN RODENTS

African Journals Online (AJOL)

behaviour, . courtship, parental and juvenile behaviour and activity patterns. ... behavioural observations were facilitated by the development of a glass-fronted ~'double-storey" cage which ..... Adolescent siblings in both single sex and mixed groups ..... Wild rodents as Laboratory Animals and their contribution to medical.

Vision in laboratory rodents-Tools to measure it and implications for behavioral research.

Science.gov (United States)

Leinonen, Henri; Tanila, Heikki

2017-07-29

Mice and rats are nocturnal mammals and their vision is specialized for detection of motion and contrast in dim light conditions. These species possess a large proportion of UV-sensitive cones in their retinas and the majority of their optic nerve axons target superior colliculus rather than visual cortex. Therefore, it was a widely held belief that laboratory rodents hardly utilize vision during day-time behavior. This dogma is being questioned as accumulating evidence suggests that laboratory rodents are able to perform complex visual functions, such as perceiving subjective contours, and that declined vision may affect their performance in many behavioral tasks. For instance, genetic engineering may have unexpected consequences on vision as mouse models of Alzheimer's and Huntington's diseases have declined visual function. Rodent vision can be tested in numerous ways using operant training or reflex-based behavioral tasks, or alternatively using electrophysiological recordings. In this article, we will first provide a summary of visual system and explain its characteristics unique to rodents. Then, we present well-established techniques to test rodent vision, with an emphasis on pattern vision: visual water test, optomotor reflex test, pattern electroretinography and pattern visual evoked potentials. Finally, we highlight the importance of visual phenotyping in rodents. As the number of genetically engineered rodent models and volume of behavioral testing increase simultaneously, the possibility of visual dysfunctions needs to be addressed. Neglect in this matter potentially leads to crude biases in the field of neuroscience and beyond. Copyright © 2017 Elsevier B.V. All rights reserved.

A test of five mechanisms of species coexistence between rodents in ...

African Journals Online (AJOL)

A test of five mechanisms of species coexistence between rodents in a southern African savanna. M.R. Perrin, B.P. Kotler. Abstract. The operation of five different mechanisms of species coexistence in a community of rodents was examined in a semi-arid Kalahari savanna in southern Africa. The two most common species ...

KEK-IMSS Slow Positron Facility

Energy Technology Data Exchange (ETDEWEB)

Hyodo, T; Wada, K; Yagishita, A; Kosuge, T; Saito, Y; Kurihara, T; Kikuchi, T; Shirakawa, A; Sanami, T; Ikeda, M; Ohsawa, S; Kakihara, K; Shidara, T, E-mail: toshio.hyodo@kek.jp [High Energy Accelerator Research Organization (KEK) 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan)

2011-12-01

The Slow Positron Facility at the Institute of Material Structure Science (IMSS) of High Energy Accelerator Research Organization (KEK) is a user dedicated facility with an energy tunable (0.1 - 35 keV) slow positron beam produced by a dedicated 55MeV linac. The present beam line branches have been used for the positronium time-of-flight (Ps-TOF) measurements, the transmission positron microscope (TPM) and the photo-detachment of Ps negative ions (Ps{sup -}). During the year 2010, a reflection high-energy positron diffraction (RHEPD) measurement station is going to be installed. The slow positron generator (converter/ moderator) system will be modified to get a higher slow positron intensity, and a new user-friendly beam line power-supply control and vacuum monitoring system is being developed. Another plan for this year is the transfer of a {sup 22}Na-based slow positron beam from RIKEN. This machine will be used for the continuous slow positron beam applications and for the orientation training of those who are interested in beginning researches with a slow positron beam.

Two-boundary first exit time of Gauss-Markov processes for stochastic modeling of acto-myosin dynamics.

Science.gov (United States)

D'Onofrio, Giuseppe; Pirozzi, Enrica

2017-05-01

We consider a stochastic differential equation in a strip, with coefficients suitably chosen to describe the acto-myosin interaction subject to time-varying forces. By simulating trajectories of the stochastic dynamics via an Euler discretization-based algorithm, we fit experimental data and determine the values of involved parameters. The steps of the myosin are represented by the exit events from the strip. Motivated by these results, we propose a specific stochastic model based on the corresponding time-inhomogeneous Gauss-Markov and diffusion process evolving between two absorbing boundaries. We specify the mean and covariance functions of the stochastic modeling process taking into account time-dependent forces including the effect of an external load. We accurately determine the probability density function (pdf) of the first exit time (FET) from the strip by solving a system of two non singular second-type Volterra integral equations via a numerical quadrature. We provide numerical estimations of the mean of FET as approximations of the dwell-time of the proteins dynamics. The percentage of backward steps is given in agreement to experimental data. Numerical and simulation results are compared and discussed.

Bifunctional Rhodamine Probes of Myosin Regulatory Light Chain Orientation in Relaxed Skeletal Muscle Fibers

Science.gov (United States)

Brack, Andrew S.; Brandmeier, Birgit D.; Ferguson, Roisean E.; Criddle, Susan; Dale, Robert E.; Irving, Malcolm

2004-01-01

The orientation of the regulatory light chain (RLC) region of the myosin heads in relaxed skinned fibers from rabbit psoas muscle was investigated by polarized fluorescence from bifunctional rhodamine (BR) probes cross-linking pairs of cysteine residues introduced into the RLC. Pure 1:1 BR-RLC complexes were exchanged into single muscle fibers in EDTA rigor solution for 30 min at 30°C; ∼60% of the native RLC was removed and stoichiometrically replaced by BR-RLC, and >85% of the BR-RLC was located in the sarcomeric A-bands. The second- and fourth-rank order parameters of the orientation distributions of BR dipoles linking RLC cysteine pairs 100-108, 100-113, 108-113, and 104-115 were calculated from polarized fluorescence intensities, and used to determine the smoothest RLC orientation distribution—the maximum entropy distribution—consistent with the polarized fluorescence data. Maximum entropy distributions in relaxed muscle were relatively broad. At the peak of the distribution, the “lever” axis, linking Cys707 and Lys843 of the myosin heavy chain, was at 70–80° to the fiber axis, and the “hook” helix (Pro830–Lys843) was almost coplanar with the fiber and lever axes. The temperature and ionic strength of the relaxing solution had small but reproducible effects on the orientation of the RLC region. PMID:15041671

Conformational distributions and proximity relationships in the rigor complex of actin and myosin subfragment-1.

Science.gov (United States)

Nyitrai, M; Hild, G; Lukács, A; Bódis, E; Somogyi, B

2000-01-28

Cyclic conformational changes in the myosin head are considered essential for muscle contraction. We hereby show that the extension of the fluorescence resonance energy transfer method described originally by Taylor et al. (Taylor, D. L., Reidler, J., Spudich, J. A., and Stryer, L. (1981) J. Cell Biol. 89, 362-367) allows determination of the position of a labeled point outside the actin filament in supramolecular complexes and also characterization of the conformational heterogeneity of an actin-binding protein while considering donor-acceptor distance distributions. Using this method we analyzed proximity relationships between two labeled points of S1 and the actin filament in the acto-S1 rigor complex. The donor (N-[[(iodoacetyl)amino]ethyl]-5-naphthylamine-1-sulfonate) was attached to either the catalytic domain (Cys-707) or the essential light chain (Cys-177) of S1, whereas the acceptor (5-(iodoacetamido)fluorescein) was attached to the actin filament (Cys-374). In contrast to the narrow positional distribution (assumed as being Gaussian) of Cys-707 (5 +/- 3 A), the positional distribution of Cys-177 was found to be broad (102 +/- 4 A). Such a broad positional distribution of the label on the essential light chain of S1 may be important in accommodating the helically arranged acto-myosin binding relative to the filament axis.

Studies into abnormal aggression in humans and rodents: Methodological and translational aspects.

Science.gov (United States)

Haller, Jozsef

2017-05-01

Here we review the principles based on which aggression is rendered abnormal in humans and laboratory rodents, and comparatively overview the main methodological approaches based on which this behavior is studied in the two categories of subjects. It appears that the discriminating property of abnormal aggression is rule breaking, which renders aggression dysfunctional from the point of view of the perpetrator. We show that rodent models of abnormal aggression were created by the translation of human conditions into rodent equivalents, and discuss how findings obtained with such models may be "translated back" to human conditions when the mechanisms underlying aggression and its possibilities of treatment are investigated. We suggest that the complementary nature of human and rodent research approaches invite a more intense cross-talk between the two sides of aggression research than the one presently observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Too slow, for Milton

OpenAIRE

Armstrong, N.

2011-01-01

Too slow, for Milton was written in 2011, as part of a memorial project for Milton Babbitt. The piece borrows harmonies from Babbitt's Composition for 12 Instruments (harmonies which Babbitt had in turn borrowed from Schoenberg's Ode to Napoleon), but unfolds them as part of a musical texture characterised by repetition, resonance, and a slow rate of change. As Babbitt once told me that my music was 'too slow', this seemed an appropriately obstinate form of homage.

Correlates of Recent Declines of Rodents in Northern and Southern Australia: Habitat Structure Is Critical.

Directory of Open Access Journals (Sweden)

Michael J Lawes

Full Text Available Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in the south. We examine potential regional effects (northern versus southern Australia on biological and ecological correlates of range decline in Australian rodents. We demonstrate that rodent declines have been greater in the south than in the tropical north, are strongly influenced by phylogeny, and are consistently greater for species inhabiting relatively open or sparsely vegetated habitat. Unlike in marsupials, where some species have much larger body size than rodents, body mass was not an important predictor of decline in rodents. All Australian rodent species are within the prey-size range of cats (throughout the continent and red foxes (in the south. Contrary to the hypothesis that mammal declines are related directly to ecosystem productivity (annual rainfall, our results are consistent with the hypothesis that disturbances such as fire and grazing, which occur in non-rainforest habitats and remove cover used by rodents for shelter, nesting and foraging, increase predation risk. We agree with calls to introduce conservation management that limits the size and intensity of fires, increases fire patchiness and reduces grazing impacts at ecological scales appropriate for rodents. Controlling feral predators, even creating predator-free reserves in relatively sparsely-vegetated habitats, is urgently required to ensure the survival of rodent species, particularly in northern Australia where declines are not yet as severe as those in the south.

Intestinal Helminths in Different Species of Rodents in North Khorasan Province, Northeast of Iran

Directory of Open Access Journals (Sweden)

Kourosh ARZAMANI

2017-06-01

Full Text Available Background: Rodents are an important source of zoonotic diseases for human. The aim of this study was to determine the infectivity of rodents with intestinal helminths in North Khorasan Province, Iran.Methods: One hundred and thirteen rodents were collected using different collection methods such as kill and live traps, digging of their burrow, filling of their hiding places with water and hand net during 2011-2013. Their alimentary canals were removed in the laboratory and helminths were determined in the department of parasitology, Tehran University of Medical Sciences.Results: Thirteen species of helminths parasites were found in 13 species of rodents, including Aspiculuris tetraptera, Hymenolepis diminuta, Nippostrongylus brasiliensis, Protospirura Seurat, Rictolaria ratti, Skrjabinitaenia lobata, Streptopharagus kuntzi, Syphacia obvelata, Taenia taeniaeformis, Trichuris muris, Cysticercus fasciolaris, Acanthocephal. spp and Trichuris spp. Some of them were reported for the first time in new host in Iran. S. obvelata and A. tetraptera were the most frequent parasites and P. Seurat, R. ratti and C. fasciolaris were found only in one rodent.Conclusion: This is the first study to investigate the intestinal parasites in rodents in this area. Among different species identified, some of helminths were reported in new host.

Intestinal Helminths in Different Species of Rodents in North Khorasan Province, Northeast of Iran.

Science.gov (United States)

Arzamani, Kourosh; Salehi, Mitra; Mobedi, Iraj; Adinezade, Amir; Hasanpour, Hamid; Alavinia, Mohammad; Darvish, Jamshid; Shirzadi, Mohammad Reza; Mohammadi, Zeinolabedin

2017-01-01

Rodents are an important source of zoonotic diseases for human. The aim of this study was to determine the infectivity of rodents with intestinal helminths in North Khorasan Province, Iran. One hundred and thirteen rodents were collected using different collection methods such as kill and live traps, digging of their burrow, filling of their hiding places with water and hand net during 2011-2013. Their alimentary canals were removed in the laboratory and helminths were determined in the department of parasitology, Tehran University of Medical Sciences. Thirteen species of helminths parasites were found in 13 species of rodents, including Aspiculuris tetraptera, Hymenolepis diminuta, Nippostrongylus brasiliensis, Protospirura Seurat, Rictolaria ratti, Skrjabinitaenia lobata, Streptopharagus kuntzi, Syphacia obvelata, Taenia taeniaeformis, Trichuris muris, Cysticercus fasciolaris, Acanthocephal. spp and Trichuris spp . Some of them were reported for the first time in new host in Iran. S. obvelata and A. tetraptera were the most frequent parasites and P. Seurat, R. ratti and C. fasciolaris were found only in one rodent. This is the first study to investigate the intestinal parasites in rodents in this area. Among different species identified, some of helminths were reported in new host.

Pesquisa de marcadores para os genes da cadeia pesada da beta-miosina cardíaca e da proteína C de ligação à miosina em familiares de pacientes com cardiomiopatia hipertrófica Research of markers for the genes of the heavy chain of cardiac beta-myosin and myosin binding protein C in relatives of patients with hypertrophic cardiomyopathy

Directory of Open Access Journals (Sweden)

Adriana Paula Tirone

2005-06-01

Full Text Available OBJETIVO: Estudar os marcadores moleculares para os genes da cadeia pesada da beta-miosina cardíaca e da proteína-C de ligação à miosina em familiares de portadores de cardiomiopatia hipertrófica. MÉTODOS: Foram estudadas 12 famílias que realizaram anamnese, exame físico, eletrocardiograma, ecocardiograma e coleta de sangue para o estudo genético através da reação em cadeia da polimerasse. RESULTADOS: Dos 227 familiares 25% eram acometidos, sendo 51% do sexo masculino com idade média de 35±19 (2 a 95 anos. A análise genética mostrou ligação com o gene da b-miosina cardíaca em uma família e, em outra, ligação com o gene da proteína C de ligação à miosina. Em cinco famílias foram excluídas ligações com os dois genes; em duas, a ligação com o gene da proteína C de ligação à miosina, porém para o gene da b-miosina os resultados foram inconclusivos; em duas famílias os resultados foram inconclusivos para os dois genes e em uma foi excluída ligação para o gene da b-miosina mas ficou inconclusivo para o gene da proteína C de ligação à miosina. CONCLUSÃO: Em nosso meio, talvez predominem outros genes que não aqueles descritos na literatura, ou que existam outras diferenças genéticas relacionadas com a origem de nossa população e/ou fatores ambientais.OBJECTIVE: To study the molecular markers for the genes of the heavy chain of cardiac beta-myosin and the myosin binding protein C in relatives of carriers of hypertrophic cardiomyopathy. METHODS: Twelve families who had anamnesis, physical exam, electrocardiogram, echocardiogram and blood collection for the genetic study through the chain reaction of polymerase. RESULTS: From the 227 relatives, 25% were ill-taken, with 51% men, with an average age of 35±19 (2 to 95 years old. The genetic analysis showed a connection with the gene of the cardiac b-myosin in a family and, in another, a connection with the gene of the myosin-binding protein C. In five

Anatomy and Histology of Rodent and Human Major Salivary Glands

Science.gov (United States)

Amano, Osamu; Mizobe, Kenichi; Bando, Yasuhiko; Sakiyama, Koji

2012-01-01

Major salivary glands of both humans and rodents consist of three pairs of macroscopic glands: parotid, submandibular, and sublingual. These glands secrete serous, mucous or mixed saliva via the proper main excretory ducts connecting the glandular bodies with the oral cavity. A series of discoveries about the salivary ducts in the 17th century by Niels Stensen (1638–1686), Thomas Wharton (1614–1673), and Caspar Bartholin (1655–1738) established the concept of exocrine secretion as well as salivary glands. Recent investigations have revealed the endocrine functions of parotin and a variety of cell growth factors produced by salivary glands. The present review aims to describe macroscopic findings on the major salivary glands of rodents and the microscopic differences between those of humans and rodents, which review should be of interest to those researchers studying salivary glands. PMID:23209333

Occurrence of ectoparasitic arthropods associated with rodents in Hail region northern Saudi Arabia.

Science.gov (United States)

Asiry, Khalid A; Fetoh, Badr El-Sabah A

2014-09-01

Ectoparasitic arthropods are a diverse element of the Saudi fauna. Due to this, a survey of ectoparasites associated with rodents was conducted as a preliminary study in five districts of Hail region of northern Saudi Arabia for the first time. Ectoparasites extracted from 750 rodents were sampled and identified by recording their frequency of appearance. Results revealed that 1,287 ectoparasites infested 316 of the captured rodent hosts. These ectoparasites parasitized on four species of rodents including three species of rats Rattus rattus rattus, Rattus rattus frugivorus, and Rattus rattus alexandrinus and one species of mouse Acomys dimidiatus (Rodentia: Muridae). The ectoparasites belong to four different groups: ticks, fleas, lice, and mites. Ticks were the highest in the number, while fleas were the lowest among all the extracted ectoparasite groups. The collected ectoparasitic arthropods consisted of seven species. Ticks were of two species: Rhipicephalus turanicus and Rhipicephalus sanguineus (Acari: Ixodidae), fleas were of two species: Xenopsylla cheopis and Xenopsyllus conformis mycerini (Siphonaptera: Pulicidae), lice was a single species: Polyplax serrata (Anoplura: Hoplopleuridae), and mites were of two species: Laelaps nuttali and Laelaps echidninus (Mesostigmata: Laelapidae). The findings of the study showed that the intensity of infestation was varied between rodent host sexes, wherein females had the highest rate of parasitic infestation, and the parasitic index of appearance was very high for one group of parasites (i.e., ticks). The parasitic prevalence was 42.13 % on rodents, and mites were the most prevalent parasite species. Overall, this study was carried out to establish baseline data for ectoparasite-infested rodents in Hail region, Saudi Arabia, and may help for appropriate planning to control zoonotic diseases in this area.

Homeobox Genes in the Rodent Pineal Gland

DEFF Research Database (Denmark)

Rath, Martin Fredensborg; Rohde, Kristian; Klein, David C

2013-01-01

The pineal gland is a neuroendocrine gland responsible for nocturnal synthesis of melatonin. During early development of the rodent pineal gland from the roof of the diencephalon, homeobox genes of the orthodenticle homeobox (Otx)- and paired box (Pax)-families are expressed and are essential...... for normal pineal development consistent with the well-established role that homeobox genes play in developmental processes. However, the pineal gland appears to be unusual because strong homeobox gene expression persists in the pineal gland of the adult brain. Accordingly, in addition to developmental...... functions, homeobox genes appear to be key regulators in postnatal phenotype maintenance in this tissue. In this paper, we review ontogenetic and phylogenetic aspects of pineal development and recent progress in understanding the involvement of homebox genes in rodent pineal development and adult function...

The role of rodents in the ecology of Ixodes ricinus and associated pathogens in Central and Eastern Europe.

Science.gov (United States)

Mihalca, Andrei D; Sándor, Attila D

2013-01-01

Rodents comprise more species than any other mammal order. Most rodents are considered keystone species in their ecological communities, hence the survival of many other species in the ecosystem depend on them. From medical point of view, this is particularly important for rodent-dependent pathogens. In the particular case of tick-borne diseases, rodents are important as hosts for vector ticks and as reservoir hosts (Lyme borreliosis, human granulocytic anaplasmosis, Crimean-Congo hemorrhagic fever, Tick-borne relapsing fevers, tick-borne rickettsioses, babesiosis). Community and population ecology of rodents was shown to be correlated with disease ecology in the case of many tick-borne diseases. In Eastern Europe, several adult hard-tick species use rodents as their principal hosts: Ixodes apronophorus, I. crenulatus, I. laguri, I. redikorzevi, I. trianguliceps. However, the majority of ticks feeding on rodents are immature stages of ticks which as adults are parasitic on larger mammals. Larvae and nymphs of Ixodes ricinus, the most abundant and medically important tick from Europe, are commonly found on rodents. This is particularly important, as many rodents are synanthropic and, together with other micromammals and birds are often the only available natural hosts for ticks in urban environments. This work reviews the correlated ecology of rodents and I. ricinus.

Helminth Infections of Rodents and Their Zoonotic Importance in Boyer-Ahmad District, Southwestern Iran

OpenAIRE

RANJBAR, Mohammad Javad; SARKARI, Bahador; MOWLAVI, Gholam Reza; SEIFOLLAHI, Zeinab; MOSHFE, Abdolali; ABDOLAHI KHABISI, Samaneh; MOBEDI, Iraj

2017-01-01

AbstractBackground: Rodents are considered as reservoirs of various zoonotic diseases including helminthic infections. The current study aimed to evaluate the prevalence of helminth infections in rodents, in Boyer-Ahmad district, Southwestern Iran.Methods: Overall, 52 rodents were captured from various areas of the district by Sherman live traps. The animals were then euthanized and dissected. During necropsy, each organ was examined macroscopically for presence of any cyst or visible parasit...

Adaptation for rodent pollination in Leucospermum arenarium (Proteaceae) despite rapid pollen loss during grooming.

Science.gov (United States)

Johnson, Christopher Michael; Pauw, Anton

2014-05-01

Plants are adapted for rodent pollination in diverse and intricate ways. This study explores an extraordinary example of these adaptations in the pincushion Leucospermum arenarium (Proteaceae) from South Africa. Live trapping and differential exclusion experiments were used to test the role of rodents versus birds and insects as pollinators. To explore the adaptive significance of geoflory, inflorescences were raised above ground level and seed production was compared. Captive rodents and flowers with artificial stigmas were used to test the effect of grooming on the rate of pollen loss. Microscopy, nectar composition analysis and manipulative experiments were used to investigate the bizarre nectar production and transport system. Differential exclusion of rodents, birds and insects demonstrated the importance of rodents in promoting seed production. Live trapping revealed that hairy-footed gerbils, Gerbillurus paeba, and striped field mice, Rhabdomys pumilio, both carried L. arenarium pollen on their forehead and rostrum, but much larger quantities ended up in faeces as a result of grooming. Terrarium experiments showed that grooming exponentially diminished the pollen loads that they carried. The nectar of L. arenarium was found to be unusually viscous and to be presented in a novel location on the petal tips, where rodents could access it without destroying the flowers. Nectar was produced inside the perianth, but was translocated to the petal tips via capillary ducts. In common with many other rodent-pollinated plants, the flowers are presented at ground level, but when raised to higher positions seed production was not reduced, indicating that selection through female function does not drive the evolution of geoflory. Despite the apparent cost of pollen lost to grooming, L. arenarium has evolved remarkable adaptations for rodent pollination and provides the first case of this pollination system in the genus.

An inducible mouse model for microvillus inclusion disease reveals a role for myosin Vb in apical and basolateral trafficking

NARCIS (Netherlands)

Schneeberger, Kerstin; Vogel, Georg F; Teunissen, Hans; van Ommen, Domenique D; Begthel, Harry; El Bouazzaoui, Layla; van Vugt, Anke H M; Beekman, Jeffrey M; Klumperman, Judith; Müller, Thomas; Janecke, Andreas; Gerner, Patrick; Huber, Lukas A; Hess, Michael W; Clevers, Hans; van Es, Johan H; Nieuwenhuis, Edward E S; Middendorp, Sabine

2015-01-01

Microvillus inclusion disease (MVID) is a rare intestinal enteropathy with an onset within a few days to months after birth, resulting in persistent watery diarrhea. Mutations in the myosin Vb gene (MYO5B) have been identified in the majority of MVID patients. However, the exact pathophysiology of

Serological Survey of Zoonotic Viruses in Invasive and Native Commensal Rodents in Senegal, West Africa.

Science.gov (United States)

Diagne, Christophe A; Charbonnel, Nathalie; Henttonen, Heikki; Sironen, Tarja; Brouat, Carine

2017-10-01

Increasing studies on rodent-borne diseases still highlight the major role of rodents as reservoirs of numerous zoonoses of which the frequency is likely to increase worldwide as a result of accelerated anthropogenic changes, including biological invasions. Such a situation makes pathogen detection in rodent populations important, especially in the context of developing countries characterized by high infectious disease burden. Here, we used indirect fluorescent antibody tests to describe the circulation of potentially zoonotic viruses in both invasive (Mus musculus domesticus and Rattus rattus) and native (Mastomys erythroleucus and Mastomys natalensis) murine rodent populations in Senegal (West Africa). Of the 672 rodents tested, we reported 22 seropositive tests for Hantavirus, Orthopoxvirus, and Mammarenavirus genera, and no evidence of viral coinfection. This study is the first to report serological detection of Orthopoxvirus in rodents from Senegal, Mammarenavirus in R. rattus from Africa, and Hantavirus in M. m. domesticus and in M. erythroleucus. Further specific identification of the viral agents highlighted here is urgently needed for crucial public health concerns.

Substituted N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamides: potent anticonvulsants that affect frequency (use) dependence and slow inactivation of sodium channels.

Science.gov (United States)

Lee, Hyosung; Park, Ki Duk; Torregrosa, Robert; Yang, Xiao-Fang; Dustrude, Erik T; Wang, Yuying; Wilson, Sarah M; Barbosa, Cindy; Xiao, Yucheng; Cummins, Theodore R; Khanna, Rajesh; Kohn, Harold

2014-07-24

We prepared 13 derivatives of N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamide that differed in type and placement of a R-substituent in the terminal aryl unit. We demonstrated that the R-substituent impacted the compound's whole animal and cellular pharmacological activities. In rodents, select compounds exhibited excellent anticonvulsant activities and protective indices (PI=TD50/ED50) that compared favorably with clinical antiseizure drugs. Compounds with a polar, aprotic R-substituent potently promoted Na+ channel slow inactivation and displayed frequency (use) inhibition of Na+ currents at low micromolar concentrations. The possible advantage of affecting these two pathways to decrease neurological hyperexcitability is discussed.

LET-99 functions in the astral furrowing pathway, where it is required for myosin enrichment in the contractile ring.

Science.gov (United States)

Price, Kari L; Rose, Lesilee S

2017-09-01

The anaphase spindle determines the position of the cytokinesis furrow, such that the contractile ring assembles in an equatorial zone between the two spindle poles. Contractile ring formation is mediated by RhoA activation at the equator by the centralspindlin complex and midzone microtubules. Astral microtubules also inhibit RhoA accumulation at the poles. In the Caenorhabditis elegans one-cell embryo, the astral microtubule-dependent pathway requires anillin, NOP-1, and LET-99. LET-99 is well characterized for generating the asymmetric cortical localization of the Gα-dependent force-generating complex that positions the spindle during asymmetric division. However, whether the role of LET-99 in cytokinesis is specific to asymmetric division and whether it acts through Gα to promote furrowing are unclear. Here we show that LET-99 contributes to furrowing in both asymmetrically and symmetrically dividing cells, independent of its function in spindle positioning and Gα regulation. LET-99 acts in a pathway parallel to anillin and is required for myosin enrichment into the contractile ring. These and other results suggest a positive feedback model in which LET-99 localizes to the presumptive cleavage furrow in response to the spindle and myosin. Once positioned there, LET-99 enhances myosin accumulation to promote furrowing in both symmetrically and asymmetrically dividing cells. © 2017 Price and Rose. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Dependence of myosin-ATPase on structure bound creatine kinase in cardiac myfibrils from rainbow trout and freshwater turtle

DEFF Research Database (Denmark)

Haagensen, L.; Jensen, D.H.; Gesser, Hans

2008-01-01

The influence of myofibrillar creatine kinase on the myosin-ATPase activity was examined in cardiac ventricular myofibrils isolated from rainbow trout (Oncorhynchus mykiss) and freshwater turtle (Trachemys scripta). The ATPase rate was assessed by recording the rephosphorylation of ADP by the pyr......The influence of myofibrillar creatine kinase on the myosin-ATPase activity was examined in cardiac ventricular myofibrils isolated from rainbow trout (Oncorhynchus mykiss) and freshwater turtle (Trachemys scripta). The ATPase rate was assessed by recording the rephosphorylation of ADP...... by the pyruvate kinase reaction alone or together with the amount of creatine formed, when myofibrillar bound creatine kinase was activated with phosphocreatine. The steady-state concentration of ADP in the solution was varied through the activity of pyruvate kinase added to the solution. For rainbow trout...... myofibrils at a high pyruvate kinase activity, creatine kinase competed for ADP but did not influence the total ATPase activity. When the ADP concentration was elevated within the physiological range by lowering the pyruvate kinase activity, creatine kinase competed efficiently and increased the ATPase...

Isolating human DNA repair genes using rodent-cell mutants

International Nuclear Information System (INIS)

Thompson, L.H.; Weber, C.A.; Brookman, K.W.; Salazar, E.P.; Stewart, S.A.; Mitchell, D.L.

1987-01-01

The DNA repair systems of rodent and human cells appear to be at least as complex genetically as those in lower eukaryotes and bacteria. The use of mutant lines of rodent cells as a means of identifying human repair genes by functional complementation offers a new approach toward studying the role of repair in mutagenesis and carcinogenesis. In each of six cases examined using hybrid cells, specific human chromosomes have been identified that correct CHO cell mutations affecting repair of damage from uv or ionizing radiations. This finding suggests that both the repair genes and proteins may be virtually interchangeable between rodent and human cells. Using cosmid vectors, human repair genes that map to chromosome 19 have cloned as functional sequences: ERCC2 and XRCC1. ERCC1 was found to have homology with the yeast excision repair gene RAD10. Transformants of repair-deficient cell lines carrying the corresponding human gene show efficient correction of repair capacity by all criteria examined. 39 refs., 1 fig., 1 tab

Slow Tourism: Exploring the discourses

Directory of Open Access Journals (Sweden)

J. Guiver

2016-05-01

Full Text Available ‘Slow travel’ and ‘slow tourism’ are relatively new, but contested, concepts. This paper examines the meanings ascribed to them in the academic literature and websites targeted at potential tourists. It finds concurrence on aspects of savouring time at the destination and investing time to appreciate the locality, its people, history, culture and products, but detects different emphases. The academic literature stresses the benefits to the destination and global sustainability, while the websites focus on the personal benefits and ways of becoming a ‘slow tourist’. Food and drink epitomise the immersion in and absorption of the destination and the multi-dimensional tourism experience, contrasted with the superficiality of mainstream tourism. The paper discusses whether tourists practising slow tourism without using the label are slow tourists or not.

Changes in myosin S1 orientation and force induced by a temperature increase.

Science.gov (United States)

Griffiths, Peter J; Bagni, Maria A; Colombini, Barbara; Amenitsch, Heinz; Bernstorff, Sigrid; Ashley, Christopher C; Cecchi, Giovanni; Ameritsch, Heinz

2002-04-16

Force generation in myosin-based motile systems is thought to result from an angular displacement of the myosin subfragment 1 (S1) tail domain with respect to the actin filament axis. In muscle, raised temperature increases the force generated by S1, implying a greater change in tail domain angular displacement. We used time-resolved x-ray diffraction to investigate the structural corollary of this force increase by measuring M3 meridional reflection intensity during sinusoidal length oscillations. This technique allows definition of S1 orientation with respect to the myofilament axis. M3 intensity changes were approximately sinusoid at low temperatures but became increasingly distorted as temperature was elevated, with the formation of a double intensity peak at maximum shortening. This increased distortion could be accounted for by assuming a shift in orientation of the tail domain of actin-bound S1 toward the orientation at which M3 intensity is maximal, which is consistent with a tail domain rotation model of force generation in which the tail approaches a more perpendicular projection from the thin filament axis at higher temperatures. In power stroke simulations, the angle between S1 tail mean position during oscillations and the position at maximum intensity decreased by 4.7 degrees, corresponding to a mean tail displacement toward the perpendicular of 0.73 nm for a temperature-induced force increase of 0.28 P(0) from 4 to 22 degrees C. Our findings suggest that at least 62% of crossbridge compliance is associated with the tail domain.

A higher-taxon approach to rodent conservation priorities for the 21st century

Directory of Open Access Journals (Sweden)

Amori, G.

2003-12-01

Full Text Available Although rodents are not considered among the most threatened mammals, there is ample historical evidence concerning the vulnerability to extinction of several rodent phylogenetic lineages. Owing to the high number of species, poor taxonomy and the lack of detailed information on population status, the assessment of threat status according to IUCN criteria has still to be considered arbitrary in some cases. Public appreciation is scarce and tends to overlook the ecological role and conservation problems of an order representing about 41 percent of mammalian species. We provide an overview of the most relevant information concerning the conservation status of rodents at the genus, subfamily, and family level. For species¿poor taxa, the importance of distinct populations is highlighted and a splitter approach in taxonomy is adopted. Considering present constraints, strategies for the conservation of rodent diversity must rely mainly on higher taxon and hot-spot approaches. A clear understanding of phyletic relationships among difficult groups -such as Rattus, for instance- is an urgent goal. Even if rodent taxonomy is still unstable, high taxon approach is amply justified from a conservation standpoint as it offers a more subtle overview of the world terrestrial biodiversity than that offered by large mammals. Of the circa 451 living rodent genera, 126 (27,9 %, representing 168 living species, deserve conservation attention according to the present study. About 76 % of genera at risk are monotypic, confirming the danger of losing a considerable amount of phylogenetic distinctiveness.

Allometric disparity in rodent evolution

OpenAIRE

Wilson LAB

2013-01-01

In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results ...

Genotyping and subtyping of Giardia and Cryptosporidium isolates from commensal rodents in China.

Science.gov (United States)

Zhao, Z; Wang, R; Zhao, W; Qi, M; Zhao, J; Zhang, L; Li, J; Liu, A

2015-05-01

Cryptosporidium and Giardia are two important zoonotic intestinal parasites responsible for diarrhoea in humans and other animals worldwide. Rodents, as reservoirs or carriers of Cryptosporidium and Giardia, are abundant and globally widespread. In the present study, we collected 232 fecal specimens from commensal rodents captured in animal farms and farm neighbourhoods in China. We collected 33 Asian house rats, 168 brown rats and 31 house mice. 6.0% (14/232) and 8.2% (19/232) of these rodents were microscopy-positive for Giardia cysts and Cryptosporidium oocysts, respectively. All 14 Giardia isolates were identified as Giardia duodenalis assemblage G at a minimum of one or maximum of three gene loci (tpi, gdh and bg). By small subunit rRNA (SSU rRNA) gene sequencing, Cryptosporidium parvum (n = 12) and Cryptosporidium muris (n = 7) were identified. The gp60 gene encoding the 60-kDa glycoprotein was successfully amplified and sequenced in nine C. parvum isolates, all of which belonged to the IIdA15G1 subtype. Observation of the same IIdA15G1 subtype in humans (previously) and in rodents (here) suggests that rodents infected with Cryptosporidium have the potential to transmit cryptosporidiosis to humans.

Two new rodent models for actinide toxicity studies

International Nuclear Information System (INIS)

Taylor, G.N.; Jones, C.W.; Gardner, P.A.; Lloyd, R.D.; Mays, C.W.; Charrier, K.E.

1981-01-01

Two small rodent species, the grasshopper mouse (Onychomys leucogaster) and the deer mouse (Peromyscus maniculatus), have tenacious and high retention in the liver and skeleton of plutonium and americium following intraperitoneal injection of Pu and Am in citrate solution. Liver retention of Pu and Am in the grasshopper mouse is higher than liver retention in the deer mouse. Both of these rodents are relatively long-lived, breed well in captivity, and adapt suitably to laboratory conditions. It is suggested that these two species of mice, in which plutonium retention is high and prolonged in both the skeleton and liver, as it is in man, may be useful animal models for actinide toxicity studies

Angiotensin II induces reorganization of the actin cytoskeleton and myosin light-chain phosphorylation in podocytes through rho/ROCK-signaling pathway

NARCIS (Netherlands)

Wang, Siyuan; Chen, Cheng; Su, Ke; Zha, Dongqing; Liang, Wei; Hillebrands, J L; van Goor, Harry; Ding, Guohua

2016-01-01

Aims In the present study, we have evaluated the effect of angiotensin II (Ang II) on actin cytoskeleton reorganization and myosin light-chain (MLC) phosphorylation in podocytes to demonstrate whether the Rho/Rho-associated coiled kinase (ROCK) pathway is involved podocyte injury. Methods Eighteen

Effects of anatomy and diet on gastrointestinal pH in rodents.

Science.gov (United States)

Kohl, Kevin D; Stengel, Ashley; Samuni-Blank, Michal; Dearing, M Denise

2013-04-01

The pH of the gastrointestinal tract can have profound influences on digestive processes. Rodents exhibit wide variation in both stomach morphology and dietary strategies, both of which may influence gut pH. Various rodent species have evolved bilocular (or semi-segmented) stomachs that may allow for more microbial growth compared to unilocular (single-chambered) stomachs. Additionally, herbivory has evolved multiple times in rodents. The high dietary fiber typical of an herbivorous diet is known to induce secretion of bicarbonate in the gut. We predicted that stomach segmentation might facilitate the separation of contents in the proximal chamber from that of the gastric stomach, facilitating a chemical environment suitable to microbial growth. To investigate the effect of stomach anatomy and diet on gut pH, several species of rodent with varying stomach morphology were fed either a high or low-fiber diet for 7 days, and pH of the proximal stomach, gastric stomach, small intestine, and cecum were measured. We discovered that rodents with bilocular stomach anatomy maintained a larger pH gradient between the proximal and gastric stomach compartments, and were able to achieve a lower absolute gastric pH compared to those with unilocular stomachs. Dietary fiber increased the pH of the small intestine, but not in any other gut regions. The stomach pH data supports the century old hypothesis that bilocular stomach anatomy creates an environment in the proximal stomach that is suitable for microbial growth. Additionally, the alkaline small intestinal pH on a high fiber diet may enhance digestion. Copyright © 2013 Wiley Periodicals, Inc.

Mechanical Defects of Muscle Fibers with Myosin Light Chain Mutants that Cause Cardiomyopathy

OpenAIRE

Roopnarine, Osha

2003-01-01

Familial hypertrophic cardiomyopathy is a disease caused by single mutations in several sarcomeric proteins, including the human myosin ventricular regulatory light chain (vRLC). The effects of four of these mutations (A13T, F18L, E22K, and P95A) in vRLC on force generation were determined as a function of Ca2+ concentration. The endogenous RLC was removed from skinned rabbit psoas muscle fibers, and replaced with either rat wildtype vRLC or recombinant rat vRLC (G13T, F18L, E22K, and P95A). ...

Fire ignition during laser surgery in pet rodents

Directory of Open Access Journals (Sweden)

Collarile Tommaso

2012-09-01

Full Text Available Abstract Background Laser surgery is an attractive alternative to other means of section device in terms of tissue inflammation and interaction, which has been extensively used in human and veterinary medicine. Although accidental ignition during laser surgeries is sporadically reported in human medical literature, to the authors’ knowledge this is the first report regarding laser-dependent fire ignition during surgery in veterinary medicine. Case presentation Two rodents, a 13-month old, 27-gram, male pet mouse (Mus musculus and a 1-year old, female Russian hamster (Phodopus sungorus, underwent surgical removal of masses with diode laser. During the surgical procedures fires ignited from the face masks. The mouse presented severe burns on the head and both forelimbs, it was hospitalized and approximately 2 months after surgery burns were resolved. The hamster presented severe burns on the face and the proximal regions of the body. At 72 hours from the accident the hamster was euthanized. Conclusion The present report suggests that fire ignition is a potential life-threatening complication of laser surgery in non-intubated rodents maintained under volatile anesthesia. High oxygen concentrations, the presence of combustible, and the narrowness of the surgical field with the face mask during laser surgery on rodents are risk factors for fire ignition.

Identification of collected ectoparasites of rodents in the west of Khuzestan Province (Ahvaz and Hovizeh, southwest of Iran

Directory of Open Access Journals (Sweden)

Mahmood Rahdar

2015-08-01

Full Text Available Objective: To determine possible parasitic arthropods fauna in certain rodent species in the west of Khuzestan Province including Ahvaz and its suburb and suburb of Hovizeh, southwest of Iran. Methods: In the current study Sherman live traps were used to catch the rodents. The rodents were identified using Iranian keys of rodents. The ectoparasites were picked up in different ways from bodies of the anesthetized rodents and stored in 70% ethanol to preserve and identified using international keys. Results: In the present study 3 species and 4 genera of ectoparasites and 4 species of rodents were identified. Conclusions: It is important to explain that the great ectoparasite biodiversity in the west of Khuzestan, with small sampling of rodents, described a high risk factor to transmit the different infectious diseases among domestic animals and humans.

Slow Earthquake Hunters: A New Citizen Science Project to Identify and Catalog Slow Slip Events in Geodetic Data

Science.gov (United States)

Bartlow, N. M.

2017-12-01

Slow Earthquake Hunters is a new citizen science project to detect, catalog, and monitor slow slip events. Slow slip events, also called "slow earthquakes", occur when faults slip too slowly to generate significant seismic radiation. They typically take between a few days and over a year to occur, and are most often found on subduction zone plate interfaces. While not dangerous in and of themselves, recent evidence suggests that monitoring slow slip events is important for earthquake hazards, as slow slip events have been known to trigger damaging "regular" earthquakes. Slow slip events, because they do not radiate seismically, are detected with a variety of methods, most commonly continuous geodetic Global Positioning System (GPS) stations. There is now a wealth of GPS data in some regions that experience slow slip events, but a reliable automated method to detect them in GPS data remains elusive. This project aims to recruit human users to view GPS time series data, with some post-processing to highlight slow slip signals, and flag slow slip events for further analysis by the scientific team. Slow Earthquake Hunters will begin with data from the Cascadia subduction zone, where geodetically detectable slow slip events with a duration of at least a few days recur at regular intervals. The project will then expand to other areas with slow slip events or other transient geodetic signals, including other subduction zones, and areas with strike-slip faults. This project has not yet rolled out to the public, and is in a beta testing phase. This presentation will show results from an initial pilot group of student participants at the University of Missouri, and solicit feedback for the future of Slow Earthquake Hunters.

A slowing-down problem

Energy Technology Data Exchange (ETDEWEB)

Carlvik, I; Pershagen, B

1958-06-15

An infinitely long circular cylinder of radius a is surrounded by an infinite moderator. Both media are non-capturing. The cylinder emits neutrons of age zero with a constant source density of S. We assume that the ratios of the slowing-down powers and of the diffusion constants are independent of the neutron energy. The slowing-down density is calculated for two cases, a) when the slowing-down power of the cylinder medium is very small, and b) when the cylinder medium is identical with the moderator. The ratios of the slowing-down density at the age {tau} and the source density in the two cases are called {psi}{sub V}, and {psi}{sub M} respectively. {psi}{sub V} and {psi}{sub M} are functions of y=a{sup 2}/4{tau}. These two functions ({psi}{sub V} and {psi}{sub M}) are calculated and tabulated for y = 0-0.25.

Myosin light chain 2-based selection of human iPSC-derived early ventricular cardiac myocytes.

Science.gov (United States)

Bizy, Alexandra; Guerrero-Serna, Guadalupe; Hu, Bin; Ponce-Balbuena, Daniela; Willis, B Cicero; Zarzoso, Manuel; Ramirez, Rafael J; Sener, Michelle F; Mundada, Lakshmi V; Klos, Matthew; Devaney, Eric J; Vikstrom, Karen L; Herron, Todd J; Jalife, José

2013-11-01

Applications of human induced pluripotent stem cell derived-cardiac myocytes (hiPSC-CMs) would be strengthened by the ability to generate specific cardiac myocyte (CM) lineages. However, purification of lineage-specific hiPSC-CMs is limited by the lack of cell marking techniques. Here, we have developed an iPSC-CM marking system using recombinant adenoviral reporter constructs with atrial- or ventricular-specific myosin light chain-2 (MLC-2) promoters. MLC-2a and MLC-2v selected hiPSC-CMs were purified by fluorescence-activated cell sorting and their biochemical and electrophysiological phenotypes analyzed. We demonstrate that the phenotype of both populations remained stable in culture and they expressed the expected sarcomeric proteins, gap junction proteins and chamber-specific transcription factors. Compared to MLC-2a cells, MLC-2v selected CMs had larger action potential amplitudes and durations. In addition, by immunofluorescence, we showed that MLC-2 isoform expression can be used to enrich hiPSC-CM consistent with early atrial and ventricular myocyte lineages. However, only the ventricular myosin light chain-2 promoter was able to purify a highly homogeneous population of iPSC-CMs. Using this approach, it is now possible to develop ventricular-specific disease models using iPSC-CMs while atrial-specific iPSC-CM cultures may require additional chamber-specific markers. © 2013.

Anatomy and histochemistry of spread-wing posture in birds. 2. Gliding flight in the California gull, Larus californicus: a paradox of fast fibers and posture.

Science.gov (United States)

Meyers, R A; Mathias, E

1997-09-01

Gliding flight is a postural activity which requires the wings to be held in a horizontal position to support the weight of the body. Postural behaviors typically utilize isometric contractions in which no change in length takes place. Due to longer actin-myosin interactions, slow contracting muscle fibers represent an economical means for this type of contraction. In specialized soaring birds, such as vultures and pelicans, a deep layer of the pectoralis muscle, composed entirely of slow fibers, is believed to perform this function. Muscles involved in gliding posture were examined in California gulls (Larus californicus) and tested for the presence of slow fibers using myosin ATPase histochemistry and antibodies. Surprisingly small numbers of slow fibers were found in the M. extensor metacarpi radialis, M. coracobrachialis cranialis, and M. coracobrachialis caudalis, which function in wrist extension, wing protraction, and body support, respectively. The low number of slow fibers in these muscles and the absence of slow fibers in muscles associated with wing extension and primary body support suggest that gulls do not require slow fibers for their postural behaviors. Gulls also lack the deep belly to the pectoralis found in other gliding birds. Since bird muscle is highly oxidative, we hypothesize that fast muscle fibers may function to maintain wing position during gliding flight in California gulls.

Neuromuscular partitioning, architectural design, and myosin fiber types of the M. vastus lateralis of the llama (Lama glama).

Science.gov (United States)

Graziotti, Guillermo H; Palencia, Pablo; Delhon, Gustavo; Rivero, José-Luis L

2004-11-01

The llama (Lama glama) is one of the few mammals of relatively large body size in which three fast myosin heavy chain isoforms (i.e., IIA, IIX, IIB) are extensively expressed in their locomotory muscles. This study was designed to gain insight into the morphological and functional organization of skeletal musculature in this peculiar animal model. The neuromuscular partitioning, architectural design, and myosin fiber types were systematically studied in the M. vastus lateralis of adult llamas (n = 15). Four nonoverlapping neuromuscular partitions or compartments were identified macroscopically (using a modified Sihler's technique for muscle depigmentation), although they did not conform strictly to the definitions of "neuromuscular compartments." Each neuromuscular partition was innervated by primary branches of the femoral nerve and was arranged within the muscle as paired partitions, two in parallel (deep-superficial compartmentalization) and the other two in-series (proximo-distal compartmentalization). These neuromuscular partitions of the muscle varied in their respective architectural designs (studied after partial digestion with diluted nitric acid) and myosin fiber type characteristics (identified immunohistochemically with specific anti-myosin monoclonal antibodies, then examined by quantitative histochemistry and image analysis). The deep partitions of the muscle had longer fibers, with lower angles of pinnation, and higher percentages of fast-glycolytic fibers than the superficial partitions of the muscle. These differences clearly suggest a division of labor in the whole M. vastus lateralis of llamas, with deep partitions exhibiting features well adapted for dynamic activities in the extension of stifle, whereas superficial portions seem to be related to the antigravitational role of the muscle in preserving the extension of the stifle during standing and stance phase of the stride. This peculiar structural and functional organization of the llama M

A collapsin response mediator protein 2 isoform controls myosin II-mediated cell migration and matrix assembly by trapping ROCK II

DEFF Research Database (Denmark)

Yoneda, Atsuko; Morgan-Fisher, Marie; Wait, Robin

2012-01-01

Collapsin response mediator protein 2 (CRMP-2) is known as a regulator of neuronal polarity and differentiation through microtubule assembly and trafficking. Here, we show that CRMP-2 is ubiquitously expressed and a splice variant (CRMP-2L), which is expressed mainly in epithelial cells among...... nonneuronal cells, regulates myosin II-mediated cellular functions, including cell migration. While the CRMP-2 short form (CRMP-2S) is recognized as a substrate of the Rho-GTP downstream kinase ROCK in neuronal cells, a CRMP-2 complex containing 2L not only bound the catalytic domain of ROCK II through two......-2L but not -2S inhibited fibronectin matrix assembly in fibroblasts. Underlying these responses, CRMP-2L regulated the kinase activity of ROCK II but not ROCK I, independent of GTP-RhoA levels. This study provides a new insight into CRMP-2 as a controller of myosin II-mediated cellular functions...

Fluorescent modification and orientation of myosin sulfhydryl 2 in skeletal muscle fibers

International Nuclear Information System (INIS)

Ajtai, K.; Burghardt, T.P.

1989-01-01

The authors describe a protocol for the selective covalent labeling of the sulfhydryl 2 (SH2) on the myosin cross-bridge in glycerinated muscle fibers using the sulfhydryl-selective label 4-[N-[(iodoacetoxy)ethyl]-N-methylamino]-7-nitrobenz-2-oxa-1,3-diazole (IANBD). The protocol promotes the specificity of IANBD by using the ability to protect sulfhydryl 1 (SH1) from modification by binding the cross-bridge to the actin filament and using cross-bridge-bound MgADP to promote the accessibility of SH2. They determined the specificity of the probe using fluorescence gel scanning of fiber-extracted proteins to isolate the probe on myosin subfragment 1 (S1), limited proteolysis of the purified S1 to isolate the probe on the 20-kilodalton fragment of S1, and titration of the free SH1's on purified S1 using the radiolabeled SH1-specific reagent [ 14 C]iodoacetamide or enzymatic activity measurements. They characterized the angular distribution of the IANBD on cross-bridges in fibers when the fibers are in rigor, in relaxation, in the presence of MgADP, and in isometric contraction using wavelength-dependent fluorescence polarization. They find that the SH2 probe distinguishes the different states of the fiber such that rigor and MgADP are ordered and maintain a similar orientation throughout the excitation wavelength domain. The relaxed cross-bridge is ordered and has an orientation that is distinct from the orientation of the cross-bridge in rigor and MgADP over the entire wavelength domain. The active isometric cross-bridge is also oriented differently from the other states, suggesting the presence of a predominant actin-bound cross-bridge state that precedes the power stroke during muscle contraction

Survey for hantaviruses, tick-borne encephalitis virus, and Rickettsia spp. in small rodents in Croatia.

Science.gov (United States)

Svoboda, Petra; Dobler, Gerhard; Markotić, Alemka; Kurolt, Ivan-Christian; Speck, Stephanie; Habuš, Josipa; Vucelja, Marko; Krajinović, Lidija Cvetko; Tadin, Ante; Margaletić, Josip; Essbauer, Sandra

2014-07-01

In Croatia, several rodent- and vector-borne agents are endemic and of medical importance. In this study, we investigated hantaviruses and, for the first time, tick-borne encephalitis virus (TBEV) and Rickettsia spp. in small wild rodents from two different sites (mountainous and lowland region) in Croatia. In total, 194 transudate and tissue samples from 170 rodents (A. flavicollis, n=115; A. agrarius, n=2; Myodes glareolus, n=53) were tested for antibodies by indirect immunofluorescence assays (IIFT) and for nucleic acids by conventional (hantaviruses) and real-time RT-/PCRs (TBEV and Rickettsia spp.). A total of 25.5% (24/94) of the rodents from the mountainous area revealed specific antibodies against hantaviruses. In all, 21.3% (20/94) of the samples from the mountainous area and 29.0% (9/31) from the lowland area yielded positive results for either Puumala virus (PUUV) or Dobrava-Belgrade virus (DOBV) using a conventional RT-PCR. All processed samples (n=194) were negative for TBEV by IIFT or real-time RT-PCR. Serological evidence of rickettsial infection was detected in 4.3% (4/94) rodents from the mountainous region. Another 3.2% (3/94) rodents were positive for Rickettsia spp. by real-time PCR. None of the rodents (n=76) from the lowland area were positive for Rickettsia spp. by real-time PCR. Dual infection of PUUV and Rickettsia spp. was found in one M. glareolus from the mountainous area by RT-PCR and real-time PCR, respectively. To our knowledge, this is the first detection of Rickettsia spp. in small rodents from Croatia. Phylogenetic analyses of S- and M-segment sequences obtained from the two study sites revealed well-supported subgroups in Croatian PUUV and DOBV. Although somewhat limited, our data showed occurrence and prevalence of PUUV, DOBV, and rickettsiae in Croatia. Further studies are warranted to confirm these data and to determine the Rickettsia species present in rodents in these areas.

Forest rodents provide directed dispersal of Jeffrey pine seeds

Science.gov (United States)

Briggs, J.S.; Wall, S.B.V.; Jenkins, S.H.

2009-01-01

Some species of animals provide directed dispersal of plant seeds by transporting them nonrandomly to microsites where their chances of producing healthy seedlings are enhanced. We investigated whether this mutualistic interaction occurs between granivorous rodents and Jeffrey pine (Pinus jeffreyi) in the eastern Sierra Nevada by comparing the effectiveness of random abiotic seed dispersal with the dispersal performed by four species of rodents: deer mice (Peromyscus maniculatus), yellow-pine and long-eared chipmunks (Tamias amoenus and T. quadrimaculatus), and golden-mantled ground squirrels (Spermophilus lateralis). We conducted two caching studies using radio-labeled seeds, the first with individual animals in field enclosures and the second with a community of rodents in open forest. We used artificial caches to compare the fates of seeds placed at the range of microsites and depths used by animals with the fates of seeds dispersed abiotically. Finally, we examined the distribution and survival of naturally establishing seedlings over an eight-year period.Several lines of evidence suggested that this community of rodents provided directed dispersal. Animals preferred to cache seeds in microsites that were favorable for emergence or survival of seedlings and avoided caching in microsites in which seedlings fared worst. Seeds buried at depths typical of animal caches (5–25 mm) produced at least five times more seedlings than did seeds on the forest floor. The four species of rodents differed in the quality of dispersal they provided. Small, shallow caches made by deer mice most resembled seeds dispersed by abiotic processes, whereas many of the large caches made by ground squirrels were buried too deeply for successful emergence of seedlings. Chipmunks made the greatest number of caches within the range of depths and microsites favorable for establishment of pine seedlings. Directed dispersal is an important element of the population dynamics of Jeffrey pine, a

Leptospira interrogans in Rodents from Cape Verde.

Science.gov (United States)

Plata-Luis, Josué; Foronda, Pilar; Martín-Alonso, Aaron; Feliu, Carlos; Alves, Joana; Gil, Horacio; Valladares, Basilio

2016-11-01

Leptospirosis is an important worldwide zoonotic disease that can infect both animals and humans. In most cases, leptospirosis is a nonspecific self-limiting illness, but some patients can develop a severe form with a high mortality. This study was carried out in Santiago Island, Cape Verde, in 2012-2013. A total of 62 wild rodents (Rattus rattus and Mus domesticus) were analyzed. The lipL32 gene, present only in pathogenic Leptospira spp., was amplified by PCR, and 16 samples were positive (25.8%). In both rodent species, Leptospira interrogans was identified. The results show the presence of pathogenic Leptospira in the three localities analyzed in Santiago. The presence of L. interrogans demonstrates a serious health risk for the population, since this species has been associated with the most severe form of leptospirosis, the Weil's disease in humans, a severe infection with jaundice, renal failure, and hemorrhage.

Comparison of new ELISA method with established SDS-PAGE method for determination of muscle myosin heavy chain isoforms

Czech Academy of Sciences Publication Activity Database

Říčný, Jan; Soukup, Tomáš

2011-01-01

Roč. 60, č. 6 (2011), s. 899-904 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA304/08/0256 Grant - others:EC(XE) LSH-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : muscle fiber types * myosin heavy chains * SDS - PAGE * immunoreactions * thyroid hormones * ELISA Subject RIV: EA - Cell Biology Impact factor: 1.555, year: 2011

The in vivo rodent test systems for assessment of carcinogenic potential

DEFF Research Database (Denmark)

van der Laan, Jan-Willem; Spindler, Per

2002-01-01

A Drug Information Association (DIA) workshop was held in May 2001 to discuss the outcome of the International Life Sciences Institute-Health and Environmental Sciences Institute (ILSI-HESI) project on alternative models for carcinogenicity assessment such as the P53(+/-) and XPA(+/-) knockout...... mouse models, the RasH2 and Tg.AC transgenic mouse models, and the neonatal mouse model. The "ICH Guideline S1B on Testing for Carcinogenicity of Pharmaceuticals" advocates that carcinogenicity testing of pharmaceuticals, when needed, might be carried out choosing one 2-year rodent carcinogenicity study...... (rat) plus one other study that supplements the 2-year study and providing additional information that is not readily available from the 2-year study: either (1) a short- or medium-term in vivo rodent test system or (2) a 2-year carcinogenicity study in a second rodent species (mouse). Another topic...

Rodent movements, densities and radionuclide concentrations at a liquid radioactive waste disposal area

International Nuclear Information System (INIS)

Halford, D.K.

1983-01-01

Movements and densities of rodents at a liquid radioactive waste disposal area were studied from June to September 1981 using trap line and assessment line techniques. The average distance between points of successive capture was 42 +- 25 (SD) m for deer mice (Peromyscus maniculatus) and 37 +- 21 m for kangaroo rats (Dipodomys ordii). Densities of deer mice averaged 10.2/ha with a population estimate of 57 within the area of rodent captures. The population estimate of 4 species of small mammals at the waste pond complex was 93. Radionuclide concentrations averaged 133 +- 97 pCi/g for rodents captured inside the disposal area boundary, 18 +- 22 pCi/g for those captured outside of the dispoal area fence and 0.50 +- 0.6 pCi/g for control animals. Species captured outside of the waste area boundary had significantly lower (P 137 Cs, 134 Cs, 60 Co and 65 Zn) in rodents at the liquid waste disposal area was estimated to be about 162 nCi

Connecting slow earthquakes to huge earthquakes

OpenAIRE

Obara, Kazushige; Kato, Aitaro

2016-01-01

Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of th...

Integrated Photonics Enabled by Slow Light

DEFF Research Database (Denmark)

Mørk, Jesper; Chen, Yuntian; Ek, Sara

2012-01-01

In this talk we will discuss the physics of slow light in semiconductor materials and in particular the possibilities offered for integrated photonics. This includes ultra-compact slow light enabled optical amplifiers, lasers and pulse sources.......In this talk we will discuss the physics of slow light in semiconductor materials and in particular the possibilities offered for integrated photonics. This includes ultra-compact slow light enabled optical amplifiers, lasers and pulse sources....

Indirect effects of rodents on arthropods in a Scandinavian boreal forest

OpenAIRE

Malá, Barbora

2016-01-01

Rodents in boreal forest are an important component of food webs. Their role as drivers of the boreal forest ecosystem is debated. As herbivores they affect plant communities and alter qualities of plants. Consequently availability of food resources for other herbivorous species is altered. In my thesis I studied whether rodents indirectly influence communities of arthropods via plant resources. It is assumed that phytophagous arthropods respond to changes in plant resources by different feed...

Endotoxin, Coliform, and Dust Levels in Various Types of Rodent Bedding

OpenAIRE

Whiteside, Tanya E; Thigpen, Julius E; Kissling, Grace E; Grant, Mary G; Forsythe, Diane B

2010-01-01

Endotoxins in grain dust, household dust, and animal bedding may induce respiratory symptoms in rodents and humans. We assayed the endotoxin, coliform, and dust levels in 20 types of rodent bedding. Endotoxin concentrations were measured by using a commercial test kit, coliform counts were determined by using conventional microbiologic procedures, and dust content was evaluated by using a rotating–tapping shaker. Paper bedding types contained significantly less endotoxin than did other beddin...

Fast and slow spindles during the sleep slow oscillation: disparate coalescence and engagement in memory processing.

Science.gov (United States)

Mölle, Matthias; Bergmann, Til O; Marshall, Lisa; Born, Jan

2011-10-01

Thalamo-cortical spindles driven by the up-state of neocortical slow (memory consolidation during sleep. We examined interactions between SOs and spindles in human slow wave sleep, focusing on the presumed existence of 2 kinds of spindles, i.e., slow frontocortical and fast centro-parietal spindles. Two experiments were performed in healthy humans (24.5 ± 0.9 y) investigating undisturbed sleep (Experiment I) and the effects of prior learning (word paired associates) vs. non-learning (Experiment II) on multichannel EEG recordings during sleep. Only fast spindles (12-15 Hz) were synchronized to the depolarizing SO up-state. Slow spindles (9-12 Hz) occurred preferentially at the transition into the SO down-state, i.e., during waning depolarization. Slow spindles also revealed a higher probability to follow rather than precede fast spindles. For sequences of individual SOs, fast spindle activity was largest for "initial" SOs, whereas SO amplitude and slow spindle activity were largest for succeeding SOs. Prior learning enhanced this pattern. The finding that fast and slow spindles occur at different times of the SO cycle points to disparate generating mechanisms for the 2 kinds of spindles. The reported temporal relationships during SO sequences suggest that fast spindles, driven by the SO up-state feed back to enhance the likelihood of succeeding SOs together with slow spindles. By enforcing such SO-spindle cycles, particularly after prior learning, fast spindles possibly play a key role in sleep-dependent memory processing.

Prenatal stressors in rodents: Effects on behavior

Directory of Open Access Journals (Sweden)

Marta Weinstock

2017-02-01

Full Text Available The current review focuses on studies in rodents published since 2008 and explores possible reasons for any differences they report in the effects of gestational stress on various types of behavior in the offspring. An abundance of experimental data shows that different maternal stressors in rodents can replicate some of the abnormalities in offspring behavior observed in humans. These include, anxiety, in juvenile and adult rats and mice, assessed in the elevated plus maze and open field tests and depression, detected in the forced swim and sucrose-preference tests. Deficits were reported in social interaction that is suggestive of pathology associated with schizophrenia, and in spatial learning and memory in adult rats in the Morris water maze test, but in most studies only males were tested. There were too few studies on the novel object recognition test at different inter-trial intervals to enable a conclusion about the effect of prenatal stress and whether any deficits are more prevalent in males. Among hippocampal glutamate receptors, NR2B was the only subtype consistently reduced in association with learning deficits. However, like in humans with schizophrenia and depression, prenatal stress lowered hippocampal levels of BDNF, which were closely correlated with decreases in hippocampal long-term potentiation. In mice, down-regulation of BDNF appeared to occur through the action of gene-methylating enzymes that are already increased above controls in prenatally-stressed neonates. In conclusion, the data obtained so far from experiments in rodents lend support to a physiological basis for the neurodevelopmental hypothesis of schizophrenia and depression.

Euthanasia using gaseous agents in laboratory rodents.

Science.gov (United States)

Valentim, A M; Guedes, S R; Pereira, A M; Antunes, L M

2016-08-01

Several questions have been raised in recent years about the euthanasia of laboratory rodents. Euthanasia using inhaled agents is considered to be a suitable aesthetic method for use with a large number of animals simultaneously. Nevertheless, its aversive potential has been criticized in terms of animal welfare. The data available regarding the use of carbon dioxide (CO2), inhaled anaesthetics (such as isoflurane, sevoflurane, halothane and enflurane), as well as carbon monoxide and inert gases are discussed throughout this review. Euthanasia of fetuses and neonates is also addressed. A table listing currently available information to ease access to data regarding euthanasia techniques using gaseous agents in laboratory rodents was compiled. Regarding better animal welfare, there is currently insufficient evidence to advocate banning or replacing CO2 in the euthanasia of rodents; however, there are hints that alternative gases are more humane. The exposure to a volatile anaesthetic gas before loss of consciousness has been proposed by some scientific studies to minimize distress; however, the impact of such a measure is not clear. Areas of inconsistency within the euthanasia literature have been highlighted recently and stem from insufficient knowledge, especially regarding the advantages of the administration of isoflurane or sevoflurane over CO2, or other methods, before loss of consciousness. Alternative methods to minimize distress may include the development of techniques aimed at inducing death in the home cage of animals. Scientific outcomes have to be considered before choosing the most suitable euthanasia method to obtain the best results and accomplish the 3Rs (replacement, reduction and refinement). © The Author(s) 2015.

Discovery of Novel Alphacoronaviruses in European Rodents and Shrews

Directory of Open Access Journals (Sweden)

Theocharis Tsoleridis

2016-03-01

Full Text Available Eight hundred and thirteen European rodents and shrews encompassing seven different species were screened for alphacoronaviruses using PCR detection. Novel alphacoronaviruses were detected in the species Rattus norvegicus, Microtus agrestis, Sorex araneus and Myodes glareolus. These, together with the recently described Lucheng virus found in China, form a distinct rodent/shrew-specific clade within the coronavirus phylogeny. Across a highly conserved region of the viral polymerase gene, the new members of this clade were up to 22% dissimilar at the nucleotide level to the previously described Lucheng virus. As such they might represent distinct species of alphacoronaviruses. These data greatly extend our knowledge of wildlife reservoirs of alphacoronaviruses.

Short interspersed elements (SINEs) of the Geomyoidea superfamily rodents.

Science.gov (United States)

Gogolevsky, Konstantin P; Kramerov, Dmitri A

2006-05-24

A new short interspersed element (SINE) was isolated from the genome of desert kangaroo rat (Dipodomys deserti) using single-primer PCR. This SINE consists of two monomers: the left monomer (IDL) resembles rodent ID element and other tRNAAla(CGC)-derived SINEs, whereas the right one (Geo) shows no similarity with known SINE sequences. PCR and hybridization analyses demonstrated that IDL-Geo SINE is restricted to the rodent superfamily Geomyoidea (families Geomyidea and Heteromyidea). Isolation and analysis of IDL-Geo from California pocket mouse (Chaetodipus californicus) and Botta's pocket gopher (Thomomys bottae) revealed some species-specific features of this SINE family. The structure and evolution of known dimeric SINEs are discussed.

Light storage via slow-light four-wave mixing

International Nuclear Information System (INIS)

Fan, Yun-Fei; Wang, Hai-Hua; Wei, Xiao-Gang; Li, Ai-Jun; Kang, Zhi-Hui; Wu, Jin-Hui; Zhang, Han-Zhuang; Xu, Huai-Liang; Gao, Jin-Yue

2012-01-01

We experimentally demonstrate a light storage via slow-light four-wave mixing in a solid-state medium with a four-level double lambda scheme. Using slow light based on electromagnetically induced transparency, we obtain a slowed four-wave mixing signal pulse together with the slowed probe pulse. During the propagation of light pulses, the storage and retrieval of both the slowed four-wave mixing pulse and the slowed probe pulse are studied by manipulating the intensities of the control fields. -- Highlights: ► A light storage via slow-light four-wave mixing is observed in a solid. ► The probe pulse is slowed under electromagnetically induced transparency. ► A slowed four-wave mixing pulse is obtained by slow light. ► The storage of slowed double pulses is studied.

Hantavirus pulmonary syndrome and rodent reservoirs in the savanna-like biome of Brazil's southeastern region.

Science.gov (United States)

Limongi, J E; Oliveira, R C; Guterres, A; Costa Neto, S F; Fernandes, J; Vicente, L H B; Coelho, M G; Ramos, V N; Ferreira, M S; Bonvicino, C R; D'Andrea, P S; Lemos, E R S

2016-04-01

This paper describes the diversity of rodent fauna in an area endemic for hantavirus cardiopulmonary syndrome (HCPS) in Brazil, the population dynamics and the relationship of rodents with hantavirus in the Cerrado (savanna-like) biome. Additionally, an analysis is made of the partial S segment sequences of the hantaviruses obtained from serologically confirmed human HCPS cases and from rodent specimens. Rodents were collected during four campaigns. Human serum samples were collected from suspected cases of HCPS at hospitals in the state of Minas Gerais. The samples antibody-reactive by ELISA were processed by RT-PCR. The PCR product was amplified and sequenced. Hantavirus was detected only in Necromys lasiurus, the wild rodent species most prevalent in the Cerrado biome (min-max: 50-83·7%). All the six human serum samples were hantavirus seropositive and five showed amplified PCR products. The analysis of the nucleotide sequences showed the circulation of a single genotype, the Araraquara hantavirus. The environmental changes that have occurred in the Cerrado biome in recent decades have favoured N. lasiurus in interspecific competition of habitats, thus increasing the risk of contact between humans and rodent species infected with hantavirus. Our data corroborate the definition of N. lasiurus as the main hantavirus reservoir in the Cerrado biome.

Detection and Characterization of Homologues of Human Hepatitis Viruses and Pegiviruses in Rodents and Bats in Vietnam.

Science.gov (United States)

Van Nguyen, Dung; Van Nguyen, Cuong; Bonsall, David; Ngo, Tue Tri; Carrique-Mas, Juan; Pham, Anh Hong; Bryant, Juliet E; Thwaites, Guy; Baker, Stephen; Woolhouse, Mark; Simmonds, Peter

2018-02-28

Rodents and bats are now widely recognised as important sources of zoonotic virus infections in other mammals, including humans. Numerous surveys have expanded our knowledge of diverse viruses in a range of rodent and bat species, including their origins, evolution, and range of hosts. In this study of pegivirus and human hepatitis-related viruses, liver and serum samples from Vietnamese rodents and bats were examined by PCR and sequencing. Nucleic acids homologous to human hepatitis B, C, E viruses were detected in liver samples of 2 (1.3%) of 157 bats, 38 (8.1%), and 14 (3%) of 470 rodents, respectively. Hepacivirus-like viruses were frequently detected (42.7%) in the bamboo rat, Rhizomys pruinosus , while pegivirus RNA was only evident in 2 (0.3%) of 638 rodent serum samples. Complete or near-complete genome sequences of HBV, HEV and pegivirus homologues closely resembled those previously reported from rodents and bats. However, complete coding region sequences of the rodent hepacivirus-like viruses substantially diverged from all of the currently classified variants and potentially represent a new species in the Hepacivirus genus. Of the viruses identified, their routes of transmission and potential to establish zoonoses remain to be determined.

Rough-legged buzzards, Arctic foxes and red foxes in a tundra ecosystem without rodents.

Directory of Open Access Journals (Sweden)

Ivan Pokrovsky

Full Text Available Small rodents with multi-annual population cycles strongly influence the dynamics of food webs, and in particular predator-prey interactions, across most of the tundra biome. Rodents are however absent from some arctic islands, and studies on performance of arctic predators under such circumstances may be very instructive since rodent cycles have been predicted to collapse in a warming Arctic. Here we document for the first time how three normally rodent-dependent predator species-rough-legged buzzard, arctic fox and red fox - perform in a low-arctic ecosystem with no rodents. During six years (in 2006-2008 and 2011-2013 we studied diet and breeding performance of these predators in the rodent-free Kolguev Island in Arctic Russia. The rough-legged buzzards, previously known to be a small rodent specialist, have only during the last two decades become established on Kolguev Island. The buzzards successfully breed on the island at stable low density, but with high productivity based on goslings and willow ptarmigan as their main prey - altogether representing a novel ecological situation for this species. Breeding density of arctic fox varied from year to year, but with stable productivity based on mainly geese as prey. The density dynamic of the arctic fox appeared to be correlated with the date of spring arrival of the geese. Red foxes breed regularly on the island but in very low numbers that appear to have been unchanged over a long period - a situation that resemble what has been recently documented from Arctic America. Our study suggests that the three predators found breeding on Kolguev Island possess capacities for shifting to changing circumstances in low-arctic ecosystem as long as other small - medium sized terrestrial herbivores are present in good numbers.

Translational Rodent Models for Research on Parasitic Protozoa-A Review of Confounders and Possibilities.

Science.gov (United States)

Ehret, Totta; Torelli, Francesca; Klotz, Christian; Pedersen, Amy B; Seeber, Frank

2017-01-01

Rodents, in particular Mus musculus , have a long and invaluable history as models for human diseases in biomedical research, although their translational value has been challenged in a number of cases. We provide some examples in which rodents have been suboptimal as models for human biology and discuss confounders which influence experiments and may explain some of the misleading results. Infections of rodents with protozoan parasites are no exception in requiring close consideration upon model choice. We focus on the significant differences between inbred, outbred and wild animals, and the importance of factors such as microbiota, which are gaining attention as crucial variables in infection experiments. Frequently, mouse or rat models are chosen for convenience, e.g., availability in the institution rather than on an unbiased evaluation of whether they provide the answer to a given question. Apart from a general discussion on translational success or failure, we provide examples where infections with single-celled parasites in a chosen lab rodent gave contradictory or misleading results, and when possible discuss the reason for this. We present emerging alternatives to traditional rodent models, such as humanized mice and organoid primary cell cultures. So-called recombinant inbred strains such as the Collaborative Cross collection are also a potential solution for certain challenges. In addition, we emphasize the advantages of using wild rodents for certain immunological, ecological, and/or behavioral questions. The experimental challenges (e.g., availability of species-specific reagents) that come with the use of such non-model systems are also discussed. Our intention is to foster critical judgment of both traditional and newly available translational rodent models for research on parasitic protozoa that can complement the existing mouse and rat models.

Translational Rodent Models for Research on Parasitic Protozoa—A Review of Confounders and Possibilities

Directory of Open Access Journals (Sweden)

Totta Ehret

2017-06-01

Full Text Available Rodents, in particular Mus musculus, have a long and invaluable history as models for human diseases in biomedical research, although their translational value has been challenged in a number of cases. We provide some examples in which rodents have been suboptimal as models for human biology and discuss confounders which influence experiments and may explain some of the misleading results. Infections of rodents with protozoan parasites are no exception in requiring close consideration upon model choice. We focus on the significant differences between inbred, outbred and wild animals, and the importance of factors such as microbiota, which are gaining attention as crucial variables in infection experiments. Frequently, mouse or rat models are chosen for convenience, e.g., availability in the institution rather than on an unbiased evaluation of whether they provide the answer to a given question. Apart from a general discussion on translational success or failure, we provide examples where infections with single-celled parasites in a chosen lab rodent gave contradictory or misleading results, and when possible discuss the reason for this. We present emerging alternatives to traditional rodent models, such as humanized mice and organoid primary cell cultures. So-called recombinant inbred strains such as the Collaborative Cross collection are also a potential solution for certain challenges. In addition, we emphasize the advantages of using wild rodents for certain immunological, ecological, and/or behavioral questions. The experimental challenges (e.g., availability of species-specific reagents that come with the use of such non-model systems are also discussed. Our intention is to foster critical judgment of both traditional and newly available translational rodent models for research on parasitic protozoa that can complement the existing mouse and rat models.

Advances in quantum simulations of ATPase catalysis in the myosin motor.

Science.gov (United States)

Kiani, Farooq Ahmad; Fischer, Stefan

2015-04-01

During its contraction cycle, the myosin motor catalyzes the hydrolysis of ATP. Several combined quantum/classical mechanics (QM/MM) studies of this step have been published, which substantially contributed to our thinking about the catalytic mechanism. The methodological difficulties encountered over the years in the simulation of this complex reaction are now understood: (a) Polarization of the protein peptide groups surrounding the highly charged ATP(4-) cannot be neglected. (b) Some unsuspected protein groups need to be treated QM. (c) Interactions with the γ-phosphate versus the β-phosphate favor a concurrent versus a sequential mechanism, respectively. Thus, these practical aspects strongly influence the computed mechanism, and should be considered when studying other catalyzed phosphor-ester hydrolysis reactions, such as in ATPases or GTPases. Copyright © 2015 Elsevier Ltd. All rights reserved.

A comparison of bats and rodents as reservoirs of zoonotic viruses: are bats special?

Science.gov (United States)

Luis, Angela D.; Hayman, David T. S.; O'Shea, Thomas J.; Cryan, Paul M.; Gilbert, Amy T.; Pulliam, Juliet R. C.; Mills, James N.; Timonin, Mary E.; Willis, Craig K. R.; Cunningham, Andrew A.; Fooks, Anthony R.; Rupprecht, Charles E.; Wood, James L. N.; Webb, Colleen T.

2013-01-01

Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs. PMID:23378666

A comparison of bats and rodents as reservoirs of zoonotic viruses: are bats special?

Science.gov (United States)

Luis, Angela D.; Hayman, David T.S.; O'Shea, Thomas J.; Cryan, Paul M.; Gilbert, Amy T.; Pulliam, Juliet R.C.; Mills, James N.; Timonin, Mary E.; Willis, Craig K.R.; Cunningham, Andrew A.; Fooks, Anthony R.; Rupprecht, Charles E.; Wood, James L.N.; Webb, Colleen T.

2013-01-01

Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs.

Hepatozoon spp. infections in wild rodents in an area of endemic canine hepatozoonosis in southeastern Brazil.

Science.gov (United States)

Demoner, Larissa de Castro; Magro, Natalia Mizuhira; da Silva, Maria Regina Lucas; de Paula Antunes, João Marcelo Azevedo; Calabuig, Cecilia Irene Pérez; O'Dwyer, Lucia Helena

2016-07-01

Hepatozoon canis is a tick-borne parasite that occurs worldwide. In rural areas of Brazil, H. canis vectors remain unknown, which has led to speculation about alternative routes of transmission. Small rodents can play a role in the transmission (via predation) of Hepatozoon americanum, which led us to question whether predation might be an alternative mode of transmission for H. canis. Thus, this study investigated whether Hepatozoon spp. are present in wild small rodents in forest fragments that surround rural areas in Botucatu County, São Paulo, Brazil, where canine hepatozoonosis is endemic. The study included blood samples from 158 dogs, which were screened by microscopy and molecular analysis. Blood samples and tissues from 67 rodents were obtained for histopathology and molecular detection. The prevalence of H. canis was high (66.45%) in dogs from rural areas of Botucatu, São Paulo, Brazil. The molecular analysis showed that wild rodent species in Brazil were infected with Hepatozoon spp. other than H. canis. Therefore, although the hypothesis that sylvatic rodents act as reservoirs for H. canis was not supported, the presence of monozoic cysts in the rodents suggests that, in addition to intermediate hosts, wild small rodents in Brazil might act as paratenic hosts of Hepatozoon spp. because they harbor infective stages for intermediate host predators. Copyright © 2016 Elsevier GmbH. All rights reserved.

Verification of natural infection of peridomestic rodents by PCV2 on commercial swine farms.

Science.gov (United States)

Pinheiro, Albanno Leonard Braz Campos; Bulos, Luiz Henrique Silva; Onofre, Thiago Souza; de Paula Gabardo, Michelle; de Carvalho, Otávio Valério; Fausto, Mariana Costa; Guedes, Roberto Maurício Carvalho; de Almeida, Márcia Rogéria; Silva Júnior, Abelardo

2013-06-01

The porcine circovirus-2 (PCV2) is the main agent responsible for porcine circovirus associated diseases (PCVAD). Few studies have been done regarding PCV2 infection in other species. The purpose of this study was to investigate the occurrence of PCV2 infection in the peridomestic rodent species Mus musculus and Rattus rattus on commercial pig farms in Brazil. Immunohistochemistry assay demonstrated PCV2 in the spleen, lung and kidney. Viral DNA was detected in tissues by nested PCR assay. Partial sequences of PCV2 genomes detected in the rodents had strong identity with gene sequences of PCV2 isolates from pigs. These results show that the studied peridomestic rodent species can be naturally infected by PCV2. However, further studies are needed to confirm PCV2 transmission from rodents to pigs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Taxonomical studies of ticks infesting wild rodents from Asir Province in Saudi Arabia.

Science.gov (United States)

Al-Mohammed, Hamdan I

2008-04-01

Ticks infesting rodents in Asir Province, which is about 3000 meter above sea level, were surveyed in Wadi Dalaghan and Wadi Bin Hachbal. They were examined from September to December 2006, where ten local life baited traps were distributed for 3 days each month. The rodents were Acomys c. dimitatus (20), Meriones rex (19) & one Gerbillus cheesmani. Fifty three nymphs were dropped off from the rodents in the laboratory 3 to 12 days post-trapping. Forty eight nymphs were reared to adults for identification and 5 ones died. The reared ticks were Rhipicephalus turanicus and R. sanguineus. The medical and veterinary importance was discussed.

Long-lived cancer-resistant rodents as new model species for cancer research

Directory of Open Access Journals (Sweden)

Jorge eAzpurua

2013-01-01

Full Text Available Most rodents are small and short-lived, but several lineages have independently evolved long lifespans without a concomitant increase in body mass. Most notably, the two subterranean species naked mole rat (NMR and blind mole rat (BMR which have maximum lifespans of 32 and 21 years respectively. The longevity of these species has sparked interest in the tumor suppression strategies that may have also evolved, because for many rodent species (including mice, rats, guinea pigs, gerbils and hamsters tumors are major source of late-life mortality. Here, we review the recent literature on anticancer mechanisms in long-lived rodents. Both NMR and BMR seem to have developed tumor defenses that rely on extra-cellular signals. However, while the NMR relies on a form of contact inhibition to suppress growth, the BMR evolved a mechanism mediated by the release of interferon and rapid necrotic cell death. Although both organisms ultimately rely on canonical downstream tumor suppressors (pRB and p53 the studies reveal species can evolve different strategies to achieve tumor-resistance. Importantly, studies of these cancer-resistant rodents may benefit human health if such mechanisms can be activated in human cells.

A glimpse on the pattern of rodent diversification

DEFF Research Database (Denmark)

Fabre, Pierre-Henri Fréderic; Hautier, Lionel; Dimitrov, Dimitar Stefanov

2012-01-01

BACKGROUND:Development of phylogenetic methods that do not rely on fossils for the study of evolutionary processes through time have revolutionized the field of evolutionary biology and resulted in an unprecedented expansion of our knowledge about the tree of life. These methods have helped to shed...... molecular works. A relaxed molecular clock dating approach provided a time framework for speciation events. We found that the Myomorpha clade shows a greater degree of variation in diversification rates than Sciuroidea, Caviomorpha, Castorimorpha and Anomaluromorpha. We identified a number of shifts...... imbalances and the time line we discuss the potential role of different diversification factors that might have shaped the rodents radiation. CONCLUSIONS:The present glimpse on the diversification pattern of rodents can be used for further comparative meta-analyses. Muroid lineages have a greater degree...

Ionic interaction of myosin loop 2 with residues located beyond the N-terminal part of actin probed by chemical cross-linking.

Science.gov (United States)

Pliszka, Barbara; Martin, Brian M; Karczewska, Emilia

2008-02-01

To probe ionic contacts of skeletal muscle myosin with negatively charged residues located beyond the N-terminal part of actin, myosin subfragment 1 (S1) and actin split by ECP32 protease (ECP-actin) were cross-linked with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). We have found that unmodified S1 can be cross-linked not only to the N-terminal part, but also to the C-terminal 36 kDa fragment of ECP-actin. Subsequent experiments performed on S1 cleaved by elastase or trypsin indicate that the cross-linking site in S1 is located within loop 2. This site is composed of Lys-636 and Lys-637 and can interact with negatively charged residues of the 36 kDa actin fragment, most probably with Glu-99 and Glu-100. Cross-links are formed both in the absence and presence of MgATP.P(i) analog, although the addition of nucleotide decreases the efficiency of the cross-linking reaction.

Slow rupture of frictional interfaces

Science.gov (United States)

Bar Sinai, Yohai; Brener, Efim A.; Bouchbinder, Eran

2012-02-01

The failure of frictional interfaces and the spatiotemporal structures that accompany it are central to a wide range of geophysical, physical and engineering systems. Recent geophysical and laboratory observations indicated that interfacial failure can be mediated by slow slip rupture phenomena which are distinct from ordinary, earthquake-like, fast rupture. These discoveries have influenced the way we think about frictional motion, yet the nature and properties of slow rupture are not completely understood. We show that slow rupture is an intrinsic and robust property of simple non-monotonic rate-and-state friction laws. It is associated with a new velocity scale cmin, determined by the friction law, below which steady state rupture cannot propagate. We further show that rupture can occur in a continuum of states, spanning a wide range of velocities from cmin to elastic wave-speeds, and predict different properties for slow rupture and ordinary fast rupture. Our results are qualitatively consistent with recent high-resolution laboratory experiments and may provide a theoretical framework for understanding slow rupture phenomena along frictional interfaces.

The Upper Miocene rodents from the Pezinok in the Danube Basin, Slovakia

OpenAIRE

Peter Joniak

2016-01-01

Rodent assemblages are described from two sampled sites at the Pezinok clay pit in the Danube Basin. Although these assemblages contain material poor in specimens, the following eleven rodent taxa are distinguished and described: Progonomys hispanicus, Kowalskia sp., Microtocricetus molassicus, Anomalomys gaillardi, Graphiurops austriacus, Paraglirulus sp., Eomyops catalaunicus, Keramidomys sp., Spermophilinus sp., Albanensia sp. and Euroxenomys minutum. The co-occurrence of very primitive Pr...

Increased myosin heavy chain-beta with atrial expression of ventricular light chain-2 in canine cardiomyopathy.

Science.gov (United States)

Fuller, Geraldine A; Bicer, Sabahattin; Hamlin, Robert L; Yamaguchi, Mamoru; Reiser, Peter J

2007-10-01

Dilated cardiomyopathy is a naturally occurring disease in humans and dogs. Human studies have shown increased levels of myosin heavy chain (MHC)-beta in failing ventricles and the left atria (LA) and of ventricular light chain (VLC)-2 in the right atria in dilated cardiomyopathy. This study evaluates the levels of MHC-beta in all heart chambers in prolonged canine right ventricular pacing. In addition, we determined whether levels of VLC2 were altered in these hearts. Failing hearts demonstrated significantly increased levels of MHC-beta in the right atria, right atrial appendage, LA, left atrial appendage (LAA), and right ventricle compared with controls. Significant levels of VLC2 were detected in the right atria of paced hearts. Differences in MHC-beta expression were observed between the LA and the LAA of paced and control dogs. MHC-beta expression was significantly greater in the LA of paced and control dogs compared with their respective LAA. The cardiac myosin isoform shifts in this study were similar to those observed in end-stage human heart failure and more severe than those reported in less prolonged pacing models, supporting the use of this model for further study of end-stage human heart failure. The observation of consistent differences between sampling sites, especially LA versus LAA, indicates the need for rigorous sampling consistency in future studies.

Mutation profile of all 49 exons of the human myosin VIIA gene, and haplotype analysis, in Usher 1B families from diverse origins.

Science.gov (United States)

Adato, A; Weil, D; Kalinski, H; Pel-Or, Y; Ayadi, H; Petit, C; Korostishevsky, M; Bonne-Tamir, B

1997-10-01

Usher syndrome types I (USH1A-USH1E) are a group of autosomal recessive diseases characterized by profound congenital hearing loss, vestibular areflexia, and progressive visual loss due to retinitis pigmentosa. The human myosin VIIA gene, located on 11q14, has been shown to be responsible for Usher syndrome type 1B (USH1B). Haplotypes were constructed in 28 USH1 families by use of the following polymorphic markers spanning the USH1B locus: D11S787, D11S527, D11S1789, D11S906, D11S4186, and OMP. Affected individuals and members of their families from 12 different ethnic origins were screened for the presence of mutations in all 49 exons of the myosin VIIA gene. In 15 families myosin VIIA mutations were detected, verifying their classification as USH1B. All these mutations are novel, including three missense mutations, one premature stop codon, two splicing mutations, one frameshift, and one deletion of >2 kb comprising exons 47 and 48, a part of exon 49, and the introns between them. Three mutations were shared by more than one family, consistent with haplotype similarities. Altogether, 16 USH1B haplotypes were observed in the 15 families; most haplotypes were population specific. Several exonic and intronic polymorphisms were also detected. None of the 20 known USH1B mutations reported so far in other world populations were identified in our families.

Endotoxin, coliform, and dust levels in various types of rodent bedding.

Science.gov (United States)

Whiteside, Tanya E; Thigpen, Julius E; Kissling, Grace E; Grant, Mary G; Forsythe, Diane

2010-03-01

Endotoxins in grain dust, household dust, and animal bedding may induce respiratory symptoms in rodents and humans. We assayed the endotoxin, coliform, and dust levels in 20 types of rodent bedding. Endotoxin concentrations were measured by using a commercial test kit, coliform counts were determined by using conventional microbiologic procedures, and dust content was evaluated by using a rotating-tapping shaker. Paper bedding types contained significantly less endotoxin than did other bedding types; the highest levels of endotoxin were detected in hardwood and corncob beddings. The range of endotoxin content for each bedding type was: corncob bedding, 1913 to 4504 endotoxin units per gram (EU/g); hardwood bedding, 3121 to 5401 EU/g; corncob-paper mixed bedding, 1586 to 2416 EU/g; and paper bedding, less than 5 to 105 EU/g. Coliform counts varied from less than 10 to 7591 cfu/g in corncob beddings, 90 to 4010 cfu/g in corncob-paper mixed beddings, less than 10 to 137 cfu/g in hardwood beddings, and less than 10 cfu/g in paper beddings. Average dust content was less than 0.15% in all commercial bedding types. We conclude that paper bedding is the optimal bedding type for conducting LPS inhalation studies and that rodent bedding containing high levels of endotoxin may alter the results of respiratory and immunologic studies in rodents.

Cardiac Myosin Binding Protein-C Autoantibodies Are Potential Early Indicators of Cardiac Dysfunction and Patient Outcome in Acute Coronary Syndrome

Directory of Open Access Journals (Sweden)

Thomas L. Lynch, IVPhD

2017-04-01

Full Text Available Summary: The degradation and release of cardiac myosin binding protein-C (cMyBP-C upon cardiac damage may stimulate an inflammatory response and autoantibody (AAb production. We determined whether the presence of cMyBP-C-AAbs associated with adverse cardiac function in cardiovascular disease patients. Importantly, cMyBP-C-AAbs were significantly detected in acute coronary syndrome patient sera upon arrival to the emergency department, particularly in ST-segment elevation myocardial infarction patients. Patients positive for cMyBP-C-AAbs had reduced left ventricular ejection fraction and elevated levels of clinical biomarkers of myocardial infarction. We conclude that cMyBP-C-AAbs may serve as early predictive indicators of deteriorating cardiac function and patient outcome in acute coronary syndrome patients prior to the infarction. Key Words: acute myocardial infarction, autoantibodies, cardiac myosin binding protein-c, cardiomyopathy

Rodent malaria parasites : genome organization & comparative genomics

NARCIS (Netherlands)