Primary Fiber Research Articles

Calretinin-immunoreactive systems in the cerebellum and cerebellum-related lateral-line medullary nuclei of an elasmobranch, Scyliorhinus canicula

Calretinin immunohistochemistry was used to study the organization of some cerebellar structures and lateral line medullary nuclei of an elasmobranch, the lesser-spotted dogfish Scyliorhinus canicula. In the cerebellar molecular layer, stellate cells are strongly calretinin-immunoreactive (CR-ir). Perikarya and dendrites of Purkinje cells are contacted by numerous stellate cell small CR-ir boutons. Some Purkinje cell perikarya are contacted by CR-ir climbing fibers forming complex axo-somatic contacts. In the granular layer, numerous CR-ir mossy fibers exhibited large swellings. Notable differences in density and diameter of mossy fibers are observed between the auricles and cerebellar body. Thin beaded CR-ir fibers are also present in the granular layer of the body. The lateral line nuclei of the octavolateralis region are comprised of a molecular-like cerebellar crest that covers the dorsal (electroreceptive) and the medial octavolateralis nuclei (mechanoreceptive). The cerebellar crest exhibited numerous CR-ir stellate cells. In the dorsal octavolateralis nucleus, the presence of conspicuous CR-ir cells and neuropil closely associated to the region of primary fiber terminals distinguishes it clearly from the medial nucleus, revealing major differences between the electroreceptive and mechanoreceptive primary nuclei of elasmobranchs. Moreover, CR distribution in the dogfish cerebellum showed interesting differences with those reported in cerebella of other vertebrates, indicating a high variability of cerebellar CR expression in phylogeny.

Transcriptional regulation of mouse alpha A-crystallin gene in a 148kb Cryaa BAC and its derivates

BackgroundαA-crystallin is highly expressed in the embryonic, neonatal and adult mouse lens. Previously, we identified two novel distal control regions, DCR1 and DCR3. DCR1 was required for transgenic expression of enhanced green fluorescent protein, EGFP, in lens epithelium, whereas DCR3 was active during "late" stages of lens primary fiber cell differentiation. However, the onset of transgenic EGFP expression was delayed by 12–24 hours, compared to the expression of the endogenous Cryaa gene.ResultsHere, we used bacterial artificial chromosome (BAC) and standard transgenic approaches to examine temporal and spatial regulation of the mouse Cryaa gene. Two BAC transgenes, with EGFP insertions into the third coding exon of Cryaa gene, were created: the intact αA-crystallin 148 kb BAC (αA-BAC) and αA-BAC(ΔDCR3), which lacks approximately 1.0 kb of genomic DNA including DCR3. Expression of EGFP in the majority of both BAC transgenics nearly recapitulated the endogenous expression pattern of the Cryaa gene in lens, but not outside of the lens. The number of cells expressing αA-crystallin in the lens pit was higher compared to the number of cells expressing EGFP. Next, we generated additional lines using a 15 kb fragment of αA-crystallin locus derived from αA-BAC(ΔDCR3), 15 kb Cryaa/EGFP. A 15 kb region of Cryaa/EGFP supported the expression pattern of EGFP also in the lens pit. However, co-localization studies of αA-crystallin and EGFP indicated that the number of cells that showed transgenic expression was higher compared to cells expressing αA-crystallin in the lens pit.ConclusionWe conclude that a 148 kb αA-BAC likely contains all of the regulatory regions required for αA-crystallin expression in the lens, but not in retina, spleen and thymus. In addition, while the 15 kb Cryaa/EGFP region also supported the expression of EGFP in the lens pit, expression in regions such as the hindbrain, indicate that additional genomic regions may play modulatory functions in regulating extralenticular αA-crystallin expression. Finally, deletion of DCR3 in either αA-BAC(ΔDCR3) or Cryaa (15 kb) transgenic mice result in EGFP expression patterns that are consistent with DCR's previously established role as a distal enhancer active in "late" primary lens fiber cells.

Role of gap junction proteins in primary fiber cell elongation

Abstract Purpose During lens development, the elongation of primary fiber cells is the first crucial step after formation of the lens vesicle. According to characterized mouse mutants, this step depends on the activity of at least three genes: Maf, Pparbp and Gjf1, which we reported recently to encode a new connexin. In all these mutants, lens development is inhibited because the primary fiber cells do not elongate and the secondary fiber cells cannot form properly. The Gjf1 gene is altered in the mouse mutant Aey12 being characterized by microphthalmia, frequently associated with cataracts. Methods To identify downstream targets of Gjf1, we performed expression profiling in Gjf1Aey12 mouse embryos at 10.5 days of development. Results At this stage, the lens placode is beginning to form the lens vesicle and histological and morphological differences between wild‐type and mutant eyes are not yet obvious. We assumed that differences in gene expression might precede the morphological Aey12 phenotype. 31 genes were identified as up‐regulated. Among them, Fhod1 shows the highest level of induction; it encodes a Formin homology‐2 domain encoding protein. Another interesting up‐regulated gene is Rai16 (coding for the retinoic acid induced protein 16) providing a new link between lens development and retinoic acid signaling. Conclusion Since retinoic acid was shown recently to be necessary for lens differentiation in quails (Maden et al., 2007), the analysis of our Aey12 mutant might contribute to a better understanding of the role of retinoic acid and connexins during early lens development in mammals.

Notch signaling regulates growth and differentiation in the mammalian lens

The Notch signal transduction pathway regulates the decision to proliferate versus differentiate. Although there are a myriad of mouse models for the Notch pathway, surprisingly little is known about how these genes regulate early eye development, particularly in the anterior lens. We employed both gain-of-function and loss-of-function approaches to determine the role of Notch signaling in lens development. Here we analyzed mice containing conditional deletion of the Notch effector Rbpj or overexpression of the activated Notch1 intracellular domain during lens formation. We demonstrate distinct functions for Notch signaling in progenitor cell growth, fiber cell differentiation and maintenance of the transition zone. In particular, Notch signaling controls the timing of primary fiber cell differentiation and is essential for secondary fiber cell differentiation. Either gain or loss of Notch signaling leads to formation of a dysgenic lens, which in loss-of-function mice undergoes a profound postnatal degeneration. Our data suggest both Cyclin D1 and Cyclin D2, and the p27 Kip1 cyclin-dependent kinase inhibitor act downstream of Notch signaling, and define multiple critical functions for this pathway during lens development.

A Bayesian framework to identify principal intravoxel diffusion profiles based on diffusion-weighted MR imaging

In this paper we introduce a new method to characterize the intravoxel anisotropy based on diffusion-weighted imaging (DWI). The proposed solution, under a fully Bayesian formalism, deals with the problem of joint Bayesian Model selection and parameter estimation to reconstruct the principal diffusion profiles or primary fiber orientations in a voxel. We develop an efficient stochastic algorithm based on the reversible jump Markov chain Monte Carlo (RJMCMC) method in order to perform the Bayesian computation. RJMCMC is a good choice for this problem because of its ability to jump between models of different dimensionality. This methodology provides posterior estimates of the parameters of interest (fiber orientation, diffusivities etc) unconditional of the model assumed. It also gives an empirical posterior distribution of the number of primary nerve fiber orientations given the DWI data. Different probability maps can be assessed using this methodology: 1) the intravoxel fiber orientation map (or orientational distribution function) that gives the probability of finding a fiber in a particular spatial orientation; 2) a three-dimensional map of the probability of finding a particular number of fibers in each voxel; 3) a three-dimensional MaxPro (maximum probability) map that provides the most probable number of fibers for each voxel.In order to study the performance and reliability of the presented approach, we tested it on synthetic data; an ex-vivo phantom of intersecting capillaries; and DWI data from a human subject.

Cleavage of softwood kraft pulp fibers by HCl and cellulases

A new pulp fibre testing procedure called the HCl method was used to compare different spruce and pine fibres and mixtures of these fibres to calculate number of fibre cleavages in dislocations and other weak points. This method was compared with treatment of softwood kraft pulp fibres using different cellulase mixtures. The HCl method can distinguish between mill- and laboratory-made softwood kraft pulp fibres from the same wood batch. The sugar release is characterized by xylose and other hemicellulose sugars and little glucose. This is in contrast to cellulases, which despite strong fibre cleavage, did not distinguish between mill- and laboratory-made pulp fibres and released large amounts of glucose from the fibres. Hemicellulose degradation by HCl and deep penetration of the acid into the primary and secondary fibre cell walls at 80°C seems to be of major importance for the differentiation between mill and laboratory pulp fibres. Cellulases, in contrast, act mostly on the fibre surfaces, and deep penetration only takes place in amorphous regions of dislocations.

Mutation in a Novel Connexin-like Gene (Gjf1) in the Mouse Affects Early Lens Development and Causes a Variable Small-Eye Phenotype

The purpose of the study was the characterization of the novel small-eye mutant Aey12 in the mouse. The eyes of the mutants were described morphologically and histologically and by in situ hybridization. The homozygotes were viable and fully fertile, which identifies Aey12 as a new microphthalmia phenotype in the mouse, different from Maf or Pax6 mutants. Histologic analysis indicated the presence of the lens vesicle; however, the primary fiber cells did not elongate properly. Genome-wide linkage analysis mapped the mutation to the proximal region of chromosome 10 between the markers D10Mit206 and D10Mit189. Among the positional candidate genes, one EST (expressed sequence tag), D230044M03Rik, encodes a connexin-like protein. A G-->T point mutation was identified at cDNA position 96, resulting in an R32Q amino acid exchange in a transmembrane domain. The mutation leads to a loss of an SsiI restriction site, which is present in five wild-type mouse strains (102, C3H, C57BL/6, DBA, and JF1). The gene is expressed in the posterior part of the lens vesicle, where the primary fiber elongation starts. In the mutants, the expression pattern of Pax6, Prox1, Six3, and Crygd are modified, but not the pattern of Pax2. The mutated mouse gene belongs to the family of connexin-encoding genes (gene symbols Gja-Gje). Together with its rat and human homologues, it defines a new subgroup, referred to as Gjf1. The mouse mutant described herein offers a new functional candidate gene for microphthalmia-related disorders at the corresponding locus on human chromosome 6, area q24.

Study on the Thick Tip of Lamb's Wool of Superfine Merino Sheep

Superfine wool of Merino sheep has many distinct characteristics, especially its higher fineness. Generally, its mean diameter is about 16.5 µm and it is a good material for fine worsted fabrics. However, the region near the tip of a primary fiber has a coarser fiber diameter, with a value of 35—66 µm. The length of such a segment is usually up to 16—22 mm. The secondary fiber also has a small swelling segment near the tip, but the length of this segment is very short and difficult to determine. The existence of such fibers with thick tips would greatly decrease the final product quality. However, the fiber diameter of the wool becomes even and unchangeable along the fiber when a lamb is 4 months old. Therefore, we suggest that lamb's wool should be sheared for other uses on lambs over 4 months of age.

Artificial neural network‐based prediction of aesthetic and functional properties of worsted suiting fabrics

PurposeThe purpose of this paper is to investigate an alternative approach that can predict non‐linear relations.Design/methodology/approachAn engineered approach to fabric development is described in which a radial basis function network is trained with worsted fabric constructional parameters to predict functional and aesthetic properties of fabrics. An objective method of fabric appearance evaluation with the help of digital image processing is introduced. The prediction of fabric properties by the network with changing basic fibre characteristics and fabric constructional parameters is found to have good correlation with the experimental values of fabric functional and aesthetic properties.FindingsThe radial basis function network can successfully predict the fabric functional and aesthetic properties from basic fibre characteristics and fabric constructional parameters with considerable accuracy. The network prediction is in good correlation with the actual experimental data. There is some error in predicting the fabric properties from the constructional parameters. The variation in the actual values and predicted values is because of small sample size. Moreover, the properties of worsted fabrics are greatly influenced by the finishing parameters which are not taken into consideration in the training of the network. Prediction performance can be further improved by including these parameters as input, during the training phase. In few cases, the network has predicted contradictory trends, which are found difficult to be explained.Originality/valueThe paper describes a radial basis function neural network model that can be used for the prediction of the fabric appearance values and comfort properties using fabric constructional parameters and some primary fibre mechanical properties as input parameters of the network.

A mutation in a novel connexin‐like gene affects early lens development in the mouse

Abstract Purpose: Aim of the study was the morphological and genetical characterization of Aey12, a novel dominant mouse mutant suffering from microphthalmia, lens and corneal opacities. Methods: A genome wide linkage analysis was performed using micro‐satellite markers. The Aey12 mutation was identified by sequence analysis of positional candidate genes. Histological analysis and in‐situ hybridizations were performed at the stages E10.5 ‐ E17.5. Results: Aey12 (abnormality of the eye) is a new dominant mouse mutant, which was recovered in an ENU mutagenesis program at the GSF. Aey12 animals are characterized by small eyes with cornea opacities and lenses with cataracts and vacuoles. Both, heterozygotes and homozygotes, are viable and fully fertile. As major histological defect, the elongation of the primary lens fibres is blocked resulting in the stop of lens development at this stage. Genome‐wide linkage analysis mapped the Aey12 mutation on mouse chromosome 10 between the markers D10Mit206 and D10Mit189. Among the positional candidate genes, one EST (D230044M03Rik) encodes a connexin‐like protein, which is similar to Connexin 43.4. A G‐T point mutation was identified at cDNA position 96 resulting in an R32Q amino acid exchange in a transmembrane domain. D230044M03Rik is expressed in the posterior part of the lens vesicle exactly at the position where the primary fiber elongation starts. Furthermore, an additional expression was observed in many other tissues like brain, lung, heart, liver and kidney. Conclusions: The new mouse mutant Aey12 is characterized by an early block of the eye development caused by a point mutation in a novel connexin‐like gene.

EHPnet: NARSAD: The Mental Health Research Association

Vol. 115, No. 8 EnvironewsOpen AccessEHPnet: NARSAD: The Mental Health Research Association Erin E. Dooley Erin E. Dooley Search for more papers by this author Published:1 August 2007https://doi.org/10.1289/ehp.115-a403Cited by:9AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit In the early 1980s, three leading national mental health groups came together to form the American Schizophrenia Association. Since that time the organization has evolved in both name and scope; it is now known as NARSAD: The Mental Health Research Association to reflect its current focus on a wide range of mental disorders. NARSAD works not only to fund research to prevent, diagnose, and treat psychiatric diseases, but also to educate the public about these conditions. Visitors can find information on these initiatives and more at http://www.narsad.org/.The Diseases and Conditions section of the NARSAD site is divided into six main sections: schizophrenia, depression, bipolar disorder, anxiety, childhood disorders, and other disorders. Each section offers a brief overview of the illness on which it focuses and a summary of symptoms and treatments. Insight into NARSAD’s research into the illness is also available. In addition, feature stories on related topics are provided, as is information for people recently diagnosed with the illness, including resources for learning about the illness they have been diagnosed with and the medications they have been prescribed.The Research Center portion of the NARSAD site provides information for potential grant recipients on how to apply for funding, provides a list of grantees, and notifies visitors of NARSAD grant deadlines. A section of project summaries gives visitors a look at the work NARSAD supports. Among other projects are a twin study to tease out the nongenetic family background contributions to depression and a mouse study of how changes in maternal behavior associated with a genetic modification may be passed to offspring that do not possess the modification.FiguresReferencesRelatedDetailsCited by Surah S, Sirohi S, Nain R and Kumar G (2018) Antimicrobial activity of TiO2 nanostructures synthesized by hydrothermal method INTERNATIONAL CONFERENCE ON STRUCTURAL ANALYSIS OF ADVANCED MATERIALS: ICSAAM 2017, 10.1063/1.5024188, , (030038) Ge G, Wu H, Xiong F, Zhang Y, Guo Z, Bian Z, Xu J, Gu C, Gu N, Chen X and Yang D (2013) The cytotoxicity evaluation of magnetic iron oxide nanoparticles on human aortic endothelial cells, Nanoscale Research Letters, 10.1186/1556-276X-8-215, 8:1, (215), . Saptarshi S, Duschl A and Lopata A (2013) Interaction of nanoparticles with proteins: relation to bio-reactivity of the nanoparticle, Journal of Nanobiotechnology, 10.1186/1477-3155-11-26, 11:1, (26), . Osmond-McLeod M, Osmond R, Oytam Y, McCall M, Feltis B, Mackay-Sim A, Wood S and Cook A (2013) Surface coatings of ZnO nanoparticles mitigate differentially a host of transcriptional, protein and signalling responses in primary human olfactory cells, Particle and Fibre Toxicology, 10.1186/1743-8977-10-54, 10:1, (54), . Sriram M, Kalishwaralal K, Barathmanikanth S and Gurunathani S (2012) Size-based cytotoxicity of silver nanoparticles in bovine retinal endothelial cells, Nanoscience Methods, 10.1080/17458080.2010.547878, 1:1, (56-77), Online publication date: 1-Jan-2012. Raemy D, Grass R, Stark W, Schumacher C, Clift M, Gehr P and Rothen-Rutishauser B (2012) Effects of flame made zinc oxide particles in human lung cells - a comparison of aerosol and suspension exposures, Particle and Fibre Toxicology, 10.1186/1743-8977-9-33, 9:1, (33), . Dua P, Chaudhari K, Lee C, Chaudhari N, Hong S, Yu J, Kim S and Lee D (2011) Evaluation of Toxicity and Gene Expression Changes Triggered by Oxide Nanoparticles, Bulletin of the Korean Chemical Society, 10.5012/bkcs.2011.32.6.2051, 32:6, (2051-2057), Online publication date: 20-Jun-2011. Kai W, Xiaojun X, Ximing P, Zhenqing H and Qiqing Z (2011) Cytotoxic effects and the mechanism of three types of magnetic nanoparticles on human hepatoma BEL-7402 cells, Nanoscale Research Letters, 10.1186/1556-276X-6-480, 6:1, (480), . Kim Y, Fazlollahi F, Kennedy I, Yacobi N, Hamm-Alvarez S, Borok Z, Kim K and Crandall E (2010) Alveolar Epithelial Cell Injury Due to Zinc Oxide Nanoparticle Exposure, American Journal of Respiratory and Critical Care Medicine, 10.1164/rccm.201002-0185OC, 182:11, (1398-1409), Online publication date: 1-Dec-2010. Vol. 115, No. 8 August 2007Metrics About Article Metrics Publication History Originally published1 August 2007Published in print1 August 2007 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. 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The arrangement and function of octopus arm musculature and connective tissue

The morphology of the musculature and connective tissues of the arms of Octopus bimaculoides was analyzed with light microscopy. We also studied O. briareus and O. digueti, which possess relatively more elongate and less elongate arms, respectively. The morphology of the arms was found to be remarkably uniform among species. The arms consist of a densely packed three-dimensional arrangement of muscle fibers and connective tissue fibers surrounding a central axial nerve cord. Three primary muscle fiber orientations were observed: 1) transverse muscle fibers oriented in planes perpendicular to the long axis of the arm; 2) longitudinal muscle fibers oriented parallel to the long axis; and 3) oblique muscle fibers arranged in helixes around the arm. The proportion of the arm cross section occupied by each of these muscle fiber groups (relative to the total cross sectional area of the musculature) remains constant along the length of the arm, even though the arm tapers from base to tip. A thin circular muscle layer wraps the arm musculature on the aboral side only. Much of this musculature has its origin and insertion on several robust connective tissue sheets including a layer surrounding the axial nerve cord and crossed-fiber connective tissue sheets located on the oral and the aboral sides of the arm. An additional thin layer of connective tissue wraps the arm musculature laterally and also serves as a site of origin and insertion of some of the muscle fibers. The fibers of the oral and aboral crossed-fiber connective tissue sheets are arranged oblique to the long axis of the arm with the same fiber angle as the oblique muscle layers that originate and insert on the sheets. The oblique muscle layers and the crossed-fiber connective tissue sheets thus form composite right- and left-handed helical fiber arrays. Analysis of arm morphology from the standpoint of biomechanics suggests that the transverse musculature is responsible for elongation of the arms, the longitudinal musculature is responsible for shortening, and the oblique muscle layers and associated connective tissues create torsion. Arm bending may involve unilateral contraction of longitudinal muscle bundles in combination with resistance to arm diameter increase due to contraction of the transverse musculature or passive stiffness of the arm tissues. The arms may also be bent by a combination of decrease in diameter due to contraction of the transverse musculature and maintenance of constant length on one side of the arm by unilateral activity of longitudinal muscle bundles. An increase in flexural stiffness of the arm may be achieved by cocontraction of the transverse and longitudinal muscle. Torsional stiffness may be increased by simultaneous contraction of both the right- and left-handed oblique muscle layers.

Design and analysis of stiffened composite panels including post-buckling and collapse

The European aircraft industry demands reduced development and operating costs, by 20% and 50% in the short and long term, respectively. Contributions to this aim are provided by the completed project POSICOSS (5th FP) and the running follow-up project COCOMAT (6th FP), both supported by the European Commission. As an important contribution to cost reduction a decrease in structural weight can be reached by exploiting considerable reserves in primary fibre composite fuselage structures through an accurate and reliable simulation of post-buckling up to collapse. The POSICOSS team developed fast procedures for the post-buckling analysis of stiffened fibre composite panels, created comprehensive experimental data bases and derived suitable design guidelines. COCOMAT builds up on the POSICOSS results and considers in addition the simulation of collapse by taking degradation into account. The results comprise an extended experimental data base, degradation models, and improved certification and design tools as well as extended design guidelines. One major task of POSICOSS and COCOMAT is the development of improved analysis tools that are validated by experiments performed within the framework of the projects. Because the new tools must comprise a wide range of various aspects a considerable number of different structures had to be tested. These structures were designed under different objectives (e.g. large post-buckling region). For the design process, the consortiums applied state-of-the-art simulation tools and brought in their own design experience. This paper deals with the design process as performed within both projects and with the applied analysis procedures. It is focused on the DLR experience in the design and analysis of stringer-stiffened CFRP panels gained within the scope of these two projects.

EXPERIMENTS ON BUCKLING AND POSTBUCKLING OF THIN-WALLED CFRP STRUCTURES USING ADVANCED MEASUREMENT SYSTEMS

The aircraft and space industry strives for significantly reduced development and operating costs. Reduction of structural weight at safe design is one possibility to reach this objective which is aimed by the following two running research projects: the EC project "COCOMAT" and the ESA study "Probabilistic Aspects of Buckling Knock Down Factors". These projects develop improved concepts and tools for a fast and reliable simulation of the buckling and the postbuckling behavior of thin-walled structures up to collapse, respectively, which allow the exploitation of considerable reserves in primary fibre composite structures in aerospace applications. For the validation of the concepts and tools, a sound database of experiments is needed which is also performed within these projects. This paper focuses on the experimental activities within these projects performed at the buckling test facility of the Institute of Composite Structures and Adaptive Systems (DLR). It presents an overview about the DLR buckling, postbuckling and collapse tests which are already finished and gives an outlook to the results which are expected until the end of the running projects. This paper explains the working of the buckling test facility, the advanced measurement systems, which are running in parallel to the tests, and gives exemplarily two test results. The structures considered are unstiffened cylinders (ESA study) as well as panels, which are understood as sections of cylinders, stiffened by stringers (COCOMAT project). The unstiffened cylinders are more related to space applications (e.g. Ariane busters or parts of the international space station ISS) and the stiffened panels focus more on aircraft structures (e.g. fuselage). The load case considered for all investigations presented in this paper is axial compression under static loading although the test facility is also ready to apply torsion and internal pressure, as well as dynamic axial impact.

Comparative study of different process steps for the near-field optical probes manufacturing

This paper deals with different methods for the manufacturing of near-field optical probes with nanometric aperture. After the wet chemical etching of the fiber, two metallization processes are compared: the well-known thermal evaporation versus the novel arrangement of plasma sputtering. Further, it is reported an original controlled nano-indentation in the smooth softness surface to produce the apex aperture of the tapered fiber. These apertures present thin protrusions, but they show good optical and topographic resolutions. Besides, the probe sensitivity is discussed with respect to the multi- and single-mode of the primary optical fiber for imaging sub-wavelength dimension objects in the collection mode.

Distinct Embryonic Expression and Localization of CBP and p300 Histone Acetyltransferases at the Mouse αA-Crystallin Locus in Lens

Mouse αA-crystallin gene encodes the most abundant protein of the mammalian lens. Expression of αA-crystallin is regulated temporally and spatially during lens development with initial expression in the lens vesicle followed by strong upregulation in the differentiating primary lens fibers. Lens-specific expression of αA-crystallin is mediated by DNA-binding transcription factors Pax6, c-Maf and CREB bound to its promoter region. Its 5′-distal enhancer, DCR1, mediates regulation of αA-crystallin via FGF signaling, while its 3′-distal enhancer, DCR3, functions only in elongated primary lens fibers via other lens differentiation pathways. DCR1 and DCR3 establish outside borders of a lens-specific chromatin region marked by histone H3 K9 acetylation. Here, we identified CREB-binding protein (CBP) and p300 as major histone acetyltransferases (HATs) associated in vivo with the mouse αA-crystallin locus. Both HATs are expressed in embryonic lens. Expression of CBP in primary lens fiber cells coincides with αA-crystallin. In the chromatin of lens epithelial cells, chromatin immunoprecipitations (ChIPs) show that the αA-crystallin promoter is notably devoid of any significant presence of CBP and p300, though DCR1 and a few other regions show the presence of these HATs. In the chromatin obtained from newborn lens, CBP was localized specifically at the promoter region with about ten times higher abundance compared to the entire αA-crystallin locus. In contrast, p300 is distributed more evenly across the entire locus. Analysis of total histone H3 and H3 K9 acetylation revealed potential lower density of nucleosomes 2 kb upstream from the promoter region. Collectively, our data suggest that moderate level of αA-crystallin gene expression in lens epithelial cells does not require the presence of CBP and p300 in the promoter. However, the lens-specific chromatin domain contains both promoter localized CBP on the “background” of locus-spread presence of CBP and p300.

Functional expression of aquaporins in embryonic, postnatal, and adult mouse lenses.

Aquaporin 0 (AQP0) and AQP1 are expressed in the lens, each in a different cell type, and their functional roles are not thoroughly understood. Our previous study showed that these two AQPs function as water transporters. In order to further understand the functional significance of these two different aquaporins in the lens, we investigated their initiation and continued expression. AQP0 transcript and protein were first detected at embryonic stage (E) 11.25 in the differentiating primary fiber cells of the developing lens; its synthesis continued through the adult stage in the secondary fiber cells. Low levels of AQP1 expression were first seen in lens anterior epithelial cells at E17.5; following postnatal day (P) 6.5, the expression gradually progressed towards the equatorial epithelial cells. In the postnatal lens, the increase in membrane water permeability of epithelial cells and lens transparency coincides with the increase in AQP1 expression. AQP1 expression reaches its peak at P30 and continues through the adult stage both in the anterior and equatorial epithelial cells. The enhancement in AQP1 expression concomitant with the increase in the size of the lens suggests the progression in the establishment of the lens microcirculatory system. In vitro and in vivo studies show that both aquaporins share at least one important function, which is water transport in the lens microcirculatory system. However, the temporal expression of these two AQPs suggests an apparently unique role/s in lens development and transparency. To our knowledge, this is the first report on the expression patterns of AQP0 and AQP1 during lens development and differentiation and their relation to lens transparency.

Development and adult morphology of the eye lens in the zebrafish

The zebrafish has become an important vertebrate model organism to study the development of the visual system. Mutagenesis projects have resulted in the identification of hundreds of eye mutants. Analysis of the phenotypes of these mutants relies on in depth knowledge of the embryogenesis in wild-type animals. While the morphological events leading to the formation of the retina and its connections to the central nervous system have been described in great detail, the characterization of the development of the eye lens is still incomplete. In the present study, we provide a morphological description of embryonic and larval lens development as well as adult lens morphology in the zebrafish. Our analyses show that, in contrast to other vertebrate species, the zebrafish lens delaminates from the surface ectoderm as a solid cluster of cells. Detachment of the prospective lens from the surface ectoderm is facilitated by apoptosis. Primary fibre cell elongation occurs in a circular fashion resulting in an embryonic lens nucleus with concentric shells of fibres. After formation of a monolayer of lens epithelial cells, differentiation and elongation of secondary lens fibres result in a final lens morphology similar to that of other vertebrate species. As in other vertebrates, secondary fibre cell differentiation includes the programmed degradation of nuclei, the interconnection of adjacent fibres via protrusions at the fibre cells' edges and the establishment of gap junctions between lens fibre cells. The very close spacing of the nuclei of the differentiating secondary fibres in a narrow zone close to the equatorial epithelium, however, suggests that secondary fibre cell differentiation deviates from that described for mammalian or avian lenses. In summary, while there are similarities in the development and final morphology of the zebrafish lens with mammalian and avian lenses, there are also significant differences, suggesting caution when extrapolating findings on the zebrafish to, for example, human lens development or function.

The Effects of Organic and Inorganic Nitrogen Fertilizer on the Morphology and Anatomy of Cannabis sativa “Fédrina” (Industrial Fibre Hemp) Grown in Northern British Columbia, Canada

Abstract The effects of organic and inorganic nitrogen fertilizer on the morphology and anatomy of Cannabis sativa “Fedrina” (industrial fibre hemp) was investigated in both a greenhouse and field setting in Northern British Columbia. Plots (90 stems/m2) treated with 0, 75, 150 or 300 kg N/ha of inorganic nitrogen, or fish meal, blood meal or sea star organic fertilizers were also replicated with 90 kg inorganic P2O5/ha application. The application of 150 and/or 300 kg N/ha of any nitrogen fertilizer type benefited field-grown plant morphology, secondary phloem fibre and xylem development, while greenhouse-grown plant morpology, secondary phloem fibre and xylem were positively influenced by 90 kg P2O5/ha. Primary phloem fibre characteristics of both greenhouse and field-grown plants were benefited by the absence of either nitrogen or phosphorus fertilizer. This study determined that the response of C. sativa “Fedrina” fibre production to organic nitrogen application was comparable to that of inorganic nit...

Ras signaling is essential for lens cell proliferation and lens growth during development

The vertebrate ocular lens is a simple and continuously growing tissue. Growth factor-mediated receptor tyrosine kinases (RTKs) are believed to be required for lens cell proliferation, differentiation and survival. The signaling pathways downstream of the RTKs remain to be elucidated. Here, we demonstrate the important role of Ras in lens development by expressing a dominant-negative form of Ras (dn-Ras) in the lens of transgenic mice. We show that lens in the transgenic mice was smaller and lens growth was severely inhibited as compared to the wild-type lens. However, the lens shape, polarity and transparency appeared normal in the transgenic mice. Further analysis showed that cell proliferation is inhibited in the dn-Ras lens. For example, the percentage of 5-bromo-2′-deoxyuridine (BrdU)-labeled cells in epithelial layer was about 2- to 3-fold lower in the transgenic lens than in the wild-type lens, implying that Ras activity is required for normal cell proliferation during lens development. We also found a small number of apoptotic cells in both epithelial and fiber compartment of the transgenic lens, suggesting that Ras also plays a role in cell survival. Interestingly, although there was a delay in primary fiber cell differentiation, secondary fiber cell differentiation was not significantly affected in the transgenic mice. For example, the expression of β- and γ-crystallins, the marker proteins for fiber differentiation, was not changed in the transgenic mice. Biochemical analysis indicated that ERK activity, but not Akt activity, was significantly reduced in the dn-Ras transgenic lenses. Overall, our data imply that the RTK-Ras-ERK signaling pathway is essential for cell proliferation and, to a lesser extent, for cell survival, but not for crystallin gene expression during fiber differentiation. Thus, some of the fiber differentiation processes are likely mediated by RTK-dependent but Ras-independent pathways.