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Insertion Line (insertion + line)
Selected AbstractsThe musculotendinous system of an anguilliform swimmer: Muscles, myosepta, dermis, and their interconnections in Anguilla rostrataJOURNAL OF MORPHOLOGY, Issue 1 2008Nicole Danos Abstract Eel locomotion is considered typical of the anguilliform swimming mode of elongate fishes and has received substantial attention from various perspectives such as swimming kinematics, hydrodynamics, muscle physiology, and computational modeling. In contrast to the extensive knowledge of swimming mechanics, there is limited knowledge of the internal body morphology, including the body components that contribute to this function. In this study, we conduct a morphological analysis of the collagenous connective tissue system, i.e., the myosepta and skin, and of the red muscle fibers that sustain steady swimming, focusing on the interconnections between these systems, such as the muscle-tendon and myosepta-skin connections. Our aim is twofold: (1) to identify the morphological features that distinguish this anguilliform swimmer from subcarangiform and carangiform swimmers, and (2) to reveal possible pathways of muscular force transmission by the connective tissue in eels. To detect gradual morphological changes along the trunk we investigated anterior (0.4L), midbody (0.6L), and posterior body positions (0.75L) using microdissections, histology, and three-dimensional reconstructions. We find that eel myosepta have a mediolaterally oriented tendon in each the epaxial and hypaxial regions (epineural or epipleural tendon) and two longitudinally oriented tendons (myorhabdoid and lateral). The latter two are relatively short (4.5,5% of body length) and remain uniform along a rostrocaudal gradient. The skin and its connections were additionally analyzed using scanning electron microscopy (SEM). The stratum compactum of the dermis consists of ,30 layers of highly ordered collagen fibers of alternating caudodorsal and caudoventral direction, with fiber angles of 60.51 ± 7.05° (n = 30) and 57.58 ± 6.92° (n = 30), respectively. Myosepta insert into the collagenous dermis via fiber bundles that pass through the loose connective tissue of the stratum spongiosum of the dermis and either weave into the layers of the stratum compactum (weaving fiber bundles) or traverse the stratum compactum (transverse fiber bundles). These fiber bundles are evenly distributed along the insertion line of the myoseptum. Red muscles insert into lateral and myorhabdoid myoseptal tendons but not into the horizontal septum or dermis. Thus, red muscle forces might be distributed along these tendons but will only be delivered indirectly into the dermis and horizontal septum. The myosepta-dermis connections, however, appear to be too slack for efficient force transmission and collagenous connections between the myosepta and the horizontal septum are at obtuse angles, a morphology that appears inadequate for efficient force transmission. Though the main modes of undulatory locomotion (anguilliform, subcarangiform, and carangiform) have recently been shown to be very similar with respect to their midline kinematics, we are able to distinguish two morphological classes with respect to the shape and tendon architecture of myosepta. Eels are similar to subcarangiform swimmers (e.g., trout) but are substantially different from carangiform swimmers (e.g., mackerel). This information, in addition to data from kinematic and hydrodynamic studies of swimming, shows that features other than midline kinematics (e.g., wake patterns, muscle activation patterns, and morphology) might be better for describing the different swimming modes of fishes. J. Morphol., 2008. © 2007 Wiley-Liss, Inc. [source] Knockout of major leaf ferredoxin reveals new redox-regulatory adaptations in Arabidopsis thalianaPHYSIOLOGIA PLANTARUM, Issue 3 2008Ingo Voss Ferredoxins are the major distributors for electrons to the various acceptor systems in plastids. In green tissues, ferredoxins are reduced by photosynthetic electron flow in the light, while in heterotrophic tissues, nicotinamide adenine dinucleotide (reduced) (NADPH) generated in the oxidative pentose-phosphate pathway (OPP) is the reductant. We have used a Ds -T-DNA insertion line of Arabidopsis thaliana for the gene encoding the major leaf ferredoxin (Fd2, At1g60950) to create a situation of high electron pressure in the thylakoids. Although these plants (Fd2-KO) possess only the minor fraction of leaf Fd1 (At1g10960), they grow photoautotrophically on soil, but with a lower growth rate and less chlorophyll. The more oxidized conditions in the stroma due to the formation of reactive oxygen species are causing a re-adjustment of the redox state in these plants that helps them to survive even under high light. Redox homeostasis is achieved by regulation at both, the post-translational and the transcriptional level. Over-reduction of the electron transport chain leads to increased transcription of the malate-valve enzyme NADP-malate dehydrogenase (MDH), and the oxidized stroma leads to an increased transcription of the OPP enzyme glucose-6-P dehydrogenase. In isolated spinach chloroplasts, oxidized conditions give rise to a decreased activation state of NADP-MDH and an activation of glucose-6-P dehydrogenase even in the light. In Fd2-KO plants, NADPH-requiring antioxidant systems are upregulated. These adjustments must be caused by plastid signals, and they prevent oxidative damage under rather severe conditions. [source] Molecular and Physiological Characterisation of an Insertion Mutant in the ARR21 Putative Response Regulator Gene from Arabidopsis thalianaPLANT BIOLOGY, Issue 3 2003J. Horák Abstract: In our search for insertion mutants of Arabidopsis response regulator (ARR) genes, we identified a candidate for an ARR21 dSpm transposon insertion line in the SLAT collection by searching the SINS sequence database. Molecular characterisation of this line revealed that the transposon is integrated as a single copy 1727 bases downstream of the ATG signal, within the third intron of the ARR21 gene. The transposon insertion segregated in a Mendelian fashion from heterozygous plants that were allowed to self-pollinate. RT-PCR-based expression analysis showed that ARR21 transcript predominantly accumulates in siliques. In contrast, the full-length ARR21 transcript was not detectable in the ARR21 transposon insertion line, indicating that it harbours an insertion of dSpm transposon in the ARR21 gene. The ARR21 insertion mutant (arr21-1) was subjected to several physiological tests for a possible insertion-linked phenotype. However, our results revealed that the insertion in the ARR21 gene did not cause any alterations in viability and fertility, flowering time, sensitivity to ethylene, cytokinin or red light. We discuss these results in the light of recent findings about the function of the other members of the response regulator gene family of Arabidopsis. [source] A leucine-rich repeat protein is required for growth promotion and enhanced seed production mediated by the endophytic fungus Piriformospora indica in Arabidopsis thalianaTHE PLANT JOURNAL, Issue 1 2007Bationa Shahollari Summary Piriformospora indica, a basidiomycete of the Sebacinaceae family, promotes the growth, development and seed production of a variety of plant species. Arabidopsis plants colonized with the fungus produce 22% more seeds than uncolonized plants. Deactivating the Arabidopsis single-copy gene DMI-1, which encodes an ion carrier required for mycorrihiza formation in legumes, does not affect the beneficial interaction between the two symbiotic partners. We used cellular and molecular responses initiated during the establishment of the interaction between P. indica and Arabidopsis roots to isolate mutants that fail to respond to the fungus. An ethylmethane sulfonate mutant (Piriformospora indica - insensitive-2; pii-2), and a corresponding insertion line, are impaired in a leucine-rich repeat protein (At1g13230). The protein pii-2, which contains a putative endoplasmic reticulum retention signal, is also found in Triton X-100-insoluble plasma membrane microdomains, suggesting that it is present in the endoplasmic reticulum/plasma membrane continuum in Arabidopsis roots. The microdomains also contain an atypical receptor protein (At5g16590) containing leucine-rich repeats, the message of which is transiently upregulated in Arabidopsis roots in response to P. indica. This response is not detectable in At1g13230 mutants, and the protein is not detectable in the At1g13230 mutant microdomains. Partial deactivation of a gene for a sphingosine kinase, which is required for the biosynthesis of sphingolipid found in plasma membrane microdomains, also affects the Arabidopsis/P. indica interaction. Thus, pii-2, and presumably also At5g16590, two proteins present in plasma membrane microdomains, appear to be involved in P. indica -induced growth promotion and enhanced seed production in Arabidopsis thaliana. [source] Disruption and overexpression of auxin response factor 8 gene of Arabidopsis affect hypocotyl elongation and root growth habit, indicating its possible involvement in auxin homeostasis in light conditionTHE PLANT JOURNAL, Issue 3 2004Chang-en Tian Summary Auxin response factor (ARF) family genes play a central role in controlling sensitivity to the plant hormone auxin. We characterized the function of ARF8, in Arabidopsis by investigating a T-DNA insertion line (arf8-1) and overexpression lines (ARF8 OX) of ARF8. arf8-1 showed a long-hypocotyl phenotype in either white, blue, red or far-red light conditions, in contrast to ARF8 OX that displayed short hypocotyls in the light. Stronger and weaker apical dominance, and promotion and inhibition of lateral root formation were observed in arf8-1 and ARF8 OX respectively. Sensitivity to auxin was unaltered in arf8-1 hypocotyls with respect to growth inhibition caused by exogenously applied auxin and growth promotion induced by higher temperatures. ARF8 expression was observed constitutively in shoot and root apexes, and was induced in the light condition in hypocotyls. Free IAA contents were approximately 30% reduced in light-grown hypocotyls of ARF8 OX, but were similar between those of arf8-1 and wild type. Expression of the three GH3 genes was reduced in arf8-1 and increased in ARF8 OX, indicating that they are targets of ARF8 transcriptional control. Because the three GH3 proteins may be involved in the conjugation of IAA as suggested by Staswick et al. (2002), and because two of the three GH3 genes are auxin inducible, ARF8 may control the free IAA level in a negative feedback fashion by regulating GH3 gene expression. ARF family genes seem to control both auxin sensitivity and homeostasis in Arabidopsis. [source] Morphological Examination of the Intraorbital Muscles (Musculi Bulbi) in Dogs in the Perinatal PeriodANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2006J. Kle, kowska Summary Twelve American Staffordshire terriers, gestational day 60, and 10 dogs de Bordeaux, gestational day 57 were examined in respect of the morphology and morphometry of their intraorbital muscles. The location of the retractor bulbi, recti and oblique muscles was described and the length of the muscles, the length and breadth of their tendons as well as the distance of the distal insertions of the muscle tendons from the corneal limbus were measured. Similarly, the shape of the line of distal insertions was investigated. The measurements were taken with an electronic caliper to the nearest 0.1 mm. The distance insertion,corneal limbus was measured by means of the Hifny and Misk method (1982). The following differences between the breeds in the morphometry of the intraorbital muscles and their tendons were found out. The distal insertions of the tendons of the dorsal, ventral and lateral recti muscles are further from the corneal limbus in American Staffordshire terriers than in dogs de Bordeaux. The muscular funiculi of the retractor bulbi muscle are further from the corneal limbus in dogs de Bordeaux, except the dorsolateral funiculus (1.96/1.94 mm). In addition, there are differences in the morphometry of the intraorbital muscles and their tendons. No differences, however, were found in the morphology of the intraorbital muscle tendons (their insertion line) and their location. The study can be applied to clinical sciences (surgery) and veterinary ophthalmology, in particular. [source] Genome-wide P -element screen for Drosophila synaptogenesis mutantsDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2006Faith L.W. Liebl Abstract A molecular understanding of synaptogenesis is a critical step toward the goal of understanding how brains "wire themselves up," and then "rewire" during development and experience. Recent genomic and molecular advances have made it possible to study synaptogenesis on a genomic scale. Here, we describe the results of a screen for genes involved in formation and development of the glutamatergic Drosophila neuromuscular junction (NMJ). We screened 2185 P -element transposon mutants representing insertions in ,16% of the entire Drosophila genome. We first identified recessive lethal mutants, based on the hypothesis that mutations causing severe disruptions in synaptogenesis are likely to be lethal. Two hundred twenty (10%) of all insertions were homozygous lethal. Two hundred five (93%) of these lethal mutants developed at least through late embryogenesis and formed neuromusculature. We examined embryonic/larval NMJs in 202 of these homozygous mutants using immunocytochemistry and confocal microscopy. We identified and classified 88 mutants with altered NMJ morphology. Insertion loci in these mutants encode several different types of proteins, including ATP- and GTPases, cytoskeletal regulators, cell adhesion molecules, kinases, phosphatases, RNA regulators, regulators of protein formation, transcription factors, and transporters. Thirteen percent of insertions are in genes that encode proteins of novel or unknown function. Complementation tests and RT-PCR assays suggest that approximately 51% of the insertion lines carry background mutations. Our results reveal that synaptogenesis requires the coordinated action of many different types of proteins,perhaps as much as 44% of the entire genome,and that transposon mutageneses carry important caveats that must be respected when interpreting results generated using this method. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] AKIN,1 is Involved in the Regulation of Nitrogen Metabolism and Sugar Signaling in ArabidopsisJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 5 2009Xiao-Fang Li Abstract Sucrose non-fermenting-1-related protein kinase 1 (SnRK1) has been located at the heart of the control of metabolism and development in plants. The active SnRK1 form is usually a heterotrimeric complex. Subcellular localization and specific target of the SnRK1 kinase are regulated by specific beta subunits. In Arabidopsis, there are at least seven genes encoding beta subunits, of which the regulatory functions are not yet clear. Here, we tried to study the function of one beta subunit, AKIN,1. It showed that AKIN,1 expression was dramatically induced by ammonia nitrate but not potassium nitrate, and the investigation of AKIN,1 transgenic Arabidopsis and T-DNA insertion lines showed that AKIN,1 negatively regulated the activity of nitrate ruductase and was positively involved in sugar repression in early seedling development. Meanwhile AKIN,1 expression was reduced upon sugar treatment (including mannitol) and did not affect the activity of sucrose phosphate synthase. The results indicate that AKIN,1 is involved in the regulation of nitrogen metabolism and sugar signaling. [source] A collection of 11 800 single-copy Ds transposon insertion lines in ArabidopsisTHE PLANT JOURNAL, Issue 6 2004Takashi Kuromori Summary More than 10 000 transposon-tagged lines were constructed by using the Activator (Ac)/Dissociation (Ds) system in order to collect insertional mutants as a useful resource for functional genomics of Arabidopsis. The flanking sequences of the Ds element in the 11 800 independent lines were determined by high-throughput analysis using a semi-automated method. The sequence data allowed us to map the unique insertion site on the Arabidopsis genome in each line. The Ds element of 7566 lines is inserted in or close to coding regions, potentially affecting the function of 5031 of 25 000 Arabidopsis genes. Half of the lines have Ds insertions on chromosome 1 (Chr. 1), in which donor lines have a donor site. In the other half, the Ds insertions are distributed throughout the other four chromosomes. The intrachromosomal distribution of Ds insertions varies with the donor lines. We found that there are hot spots for Ds transposition near the ends of every chromosome, and we found some statistical preference for Ds insertion targets at the nucleotide level. On the basis of systematic analysis of the Ds insertion sites in the 11 800 lines, we propose the use of Ds -tagged lines with a single insertion in annotated genes for systematic analysis of phenotypes (phenome analysis) in functional genomics. We have opened a searchable database of the insertion-site sequences and mutated genes (http://rarge.gsc.riken.go.jp/) and are depositing these lines in the RIKEN BioResource Center as available resources (http://www.brc.riken.go.jp/Eng/). [source] | ||||||||||