Complete Closed Genome Sequences of Mannheimia haemolytica Serotypes A1 and A6, Isolated from Cattle.

Mannheimia haemolytica is a respiratory pathogen affecting cattle and related ruminants worldwide. M. haemolytica is commonly associated with bovine respiratory disease complex (BRDC), a polymicrobial multifactorial disease.

Nondestructive volumetric imaging of tissue microstructure with benchtop x-ray phase-contrast tomography and critical point drying.

The in vitro investigation of many optically opaque biological microstructures requires 3D analysis at high resolution over a large field of view. We demonstrate a new nondestructive volumetric imaging technique that eliminates the structural and computational limitations of conventional 2D optical microscopy by combining x-ray phase-contrast tomography with critical point drying sample preparation. We experimentally demonstrate the enhancement of small features afforded by phase-contrast imaging and show the contrast improvement afforded by the drying of a hydrated specimen.

Perturbing the ubiquitin pathway reveals how mitosis is hijacked to denucleate and regulate cell proliferation and differentiation in vivo.

Background: The eye lens presents a unique opportunity to explore roles for specific molecules in cell proliferation, differentiation and development because cells remain in place throughout life and, like red blood cells and keratinocytes, they go through the most extreme differentiation, including removal of nuclei and cessation of protein synthesis. Ubiquitination controls many critical cellular processes, most of which require specific lysines on ubiquitin (Ub). Of the 7 lysines (K) least is known about effects of modification of K6.

Bacterial pathogens of the bovine respiratory disease complex.

Pneumonia caused by the bacterial pathogens discussed in this article is the most significant cause of morbidity and mortality of the BRDC. Most of these infectious bacteria are not capable of inducing significant disease without the presence of other predisposing environmental factors, physiologic stressors, or concurrent infections. Mannheimia haemolytica is the most common and serious of these bacterial agents and is therefore also the most highly characterized.

Alzheimer's disease amyloid-beta links lens and brain pathology in Down syndrome.

Down syndrome (DS, trisomy 21) is the most common chromosomal disorder and the leading genetic cause of intellectual disability in humans. In DS, triplication of chromosome 21 invariably includes the APP gene (21q21) encoding the Alzheimer's disease (AD) amyloid precursor protein (APP). Triplication of the APP gene accelerates APP expression leading to cerebral accumulation of APP-derived amyloid-beta peptides (Abeta), early-onset AD neuropathology, and age-dependent cognitive sequelae.

Tropomodulin1 is required for membrane skeleton organization and hexagonal geometry of fiber cells in the mouse lens.

Hexagonal packing geometry is a hallmark of close-packed epithelial cells in metazoans. Here, we used fiber cells of the vertebrate eye lens as a model system to determine how the membrane skeleton controls hexagonal packing of post-mitotic cells. The membrane skeleton consists of spectrin tetramers linked to actin filaments (F-actin), which are capped by tropomodulin1 (Tmod1) and stabilized by tropomyosin (TM).

Multiple and additive functions of ALDH3A1 and ALDH1A1: cataract phenotype and ocular oxidative damage in Aldh3a1(-/-)/Aldh1a1(-/-) knock-out mice.

ALDH3A1 (aldehyde dehydrogenase 3A1) is abundant in the mouse cornea but undetectable in the lens, and ALDH1A1 is present at lower (catalytic) levels in the cornea and lens. To test the hypothesis that ALDH3A1 and ALDH1A1 protect the anterior segment of the eye against environmentally induced oxidative damage, Aldh1a1(-/-)/Aldh3a1(-/-) double knock-out and Aldh1a1(-/-) and Aldh3a1(-/-) single knock-out mice were evaluated for biochemical changes and cataract formation (lens opacification). The Aldh1a1/Aldh3a1- and Aldh3a1-null mice develop cataracts in the anterior and posterior subcapsular regions as well as punctate opacities in the cortex by 1 month of age.

Age-related cataracts in alpha3Cx46-knockout mice are dependent on a calpain 3 isoform.

Purpose: Previous studies have demonstrated that in 129alpha3Cx46-/- mice, age-related nuclear cataract is formed. In the present study, a more in vivo-relevant model was generated to test the hypothesis that the calpain 3 gene is involved in age-related nuclear cataractogenesis in alpha3Cx46 knockout mice.

Methods: To test the hypothesis that the calpain 3 gene is involved in age-related nuclear cataractogenesis in alpha3Cx46 knockout mice, 129alpha3Cx46-/- and CAPN3-/- mice were mated to generate homozygous double-knockout (dKO) mice.

Transgenic overexpression of connexin50 induces cataracts.

To examine the effects of increased expression of Cx50 in the mouse lens, transgenic mice were generated using a DNA construct containing the human Cx50 coding region and a C-terminal FLAG epitope driven by the chicken betaB1-crystallin promoter. Expression of this protein in paired Xenopus oocytes induced gap junctional currents of similar magnitude to wild type human Cx50. Three lines of transgenic mice expressing the transgenic protein were analyzed.

Quantitative analysis of animal model lens anatomy: accommodative range is related to fiber structure and organization.

Purpose: The results of a recent study on accommodation in humans and baboons has revealed that lens fiber structure and organization are key components of the mechanism of accommodation. Dynamic focusing involves the controlled displacement and replacement, or realignment, of cortical fiber-ends at sutures as the mechanism of accommodation at the fiber level. This emended explanation of the mechanism of accommodation raises the following question: as the structure of crystalline lenses are only similar, not identical between species, is accommodative amplitude related to differences in the structure and organization of fibers between species? To address this question, we have quantitatively examined the structure and organization of fibers in a number of the more commonly used animal models (mice, cattle, frogs, rabbits and chickens) for lens research.

Computer modeling of secondary fiber development and growth: I. Nonprimate lenses.

Purpose: The purpose of this study was to use qualitative and quantitative structural data from nonprimate lenses with branched (Y and line) sutures to generate computer models (animations) of secondary fiber development and suture formation.

Methods: A minimum of 12-18 adult lenses/species (mice, cows, frogs, and rabbits) were used in this study. Lenses were analyzed by light (LM), transmission (TEM), and scanning electron microscopy (SEM).

First safety study of femtosecond laser photodisruption in animal lenses: tissue morphology and cataractogenesis.

Purpose: To determine through safety studies the tissue effects and potential cataractogenesis of laser modification of the crystalline lens (photophaco modulation).

Setting: Laser Zentrum Hannover, Hannover, Germany.

Methods: Six fresh porcine lenses and 6 living rabbit eyes (with the contralateral eye as a control) were radiated with a low-energy femtosecond laser to induce lens fiber disruption.

Molecular phylogeny of coral-reef sea cucumbers (Holothuriidae: Aspidochirotida) based on 16S mitochondrial ribosomal DNA sequence.

Members of the Holothuriidae, found globally at low to middle latitudes, are often a dominant component of Indo-West Pacific coral reefs. We present the first phylogeny of the group, using 8 species from the 5 currently recognized genera and based on approximately 540 nucleotides from a polymerase chain reaction-amplified and conserved 3' section of 16S mitochondrial ribosomal DNA. Parsimony and likelihood analyses returned identical topologies, permitting several robust inferences to be drawn.

Development of lens sutures.

Cylindrical map projections (CMPs) have been used for centuries as an effective means of plotting the features of a 3D spheroidal surfaces (e.g. the earth) on a 2D rectangular map.

Fibre cell organization in crystalline lenses.

This review qualitatively and quantitatively compares the gross shape and size of lenses from different species as a function of their fibre cell organization. Grossly, all vertebrate lenses are asymmetrical, oblate spheroids with size and spheroidicity that varies considerably between species. Correlative LM and SEM analysis of the basic structural element of lenses, the fibre cell, shows that the average equatorial fibre width and thickness is relatively constant between most species.

Lens structure in MIP-deficient mice.

In this study we used correlative light, scanning, and transmission (freeze-etch) electron microscopy to characterize lens structure in normal mice and compare it with that in mice deficient in the major intrinsic protein (MIP) of fiber cells. Grossly, wild-type lenses were transparent and had typical Y sutures at all of the ages examined. These lenses had fibers of uniform shape (hexagonal in cross section) arranged in ordered concentric growth shells and radial cell columns.

Morphology and organization of posterior fiber ends during migration.

Purpose: To characterize structural parameters of the basal membrane complex (BMC) and to determine the arrangement and organization of posterior fiber ends during elongation/migration in lenses with branched sutures.

Methods: Lenses from normal, juvenile (4-6 week old) Sprague-Dawley rats (n=16) were utilized. Posterior fiber ends were assessed on both whole mounts of lens capsules and on decapsulated lenses.

Knockout of the intermediate filament protein CP49 destabilises the lens fibre cell cytoskeleton and decreases lens optical quality, but does not induce cataract.

In this report, the phenotype associated with the first targeted knockout of the lens specific intermediate filament gene CP49 is described. Several surprising observations have been made. The first was that no cataract was observed despite the fact that the beaded filaments of the lens fibre cells had been disrupted.

Discordant expression of the sterol pathway in lens underlies simvastatin-induced cataracts in Chbb: Thom rats.

Simvastatin rapidly induced cataracts in young Chbb:Thom (CT) but not Sprague Dawley (SD) or Hilltop Wistar (HW) rats. Oral treatment for 14 but not 7 days committed CT rat lenses to cataract formation. The cholesterol to phospholipid molar ratio in lenses of treated CT rats was unchanged.

Neurologic defects and selective disruption of basement membranes in mice lacking entactin-1/nidogen-1.

Entactin-1 (nidogen-1) is an ubiquitous component of basement membranes. From in vitro experiments, entactin-1 was assigned a role in maintaining the structural integrity of the basement membrane because of its binding affinity to other components, such as type IV collagen and laminin. Entactin-1 also interacts with integrin receptors on the cell surface to mediate cell adhesion, spreading, and motility.

Suppression of post-vitrectomy lens changes in the rabbit by novel benzopyranyl esters and amides.

This study reports for the first time a therapeutic modality for the suppression of posterior subcapsular cataract (PSC) formation in an animal model (rabbit) of vitrectomy. This therapeutic modality may also have the potential to attenuate/prevent the high incidence of loss of vision due to cataract formation in patients that undergo vitrectomy. Unilateral, partial vitrectomy was performed on 2.

A quantitative analysis of sutural contributions to variability in back vertex distance and transmittance in rabbit lenses as a function of development, growth, and age.

Purpose: To correlate specific parameters of lens structure (anterior and posterior suture branch length and planar area) with variability in back vertex distance (BVD) and scatter in rabbit lenses as a function of development, growth, and age.

Methods: Lenses from juvenile (n = 9), adult (n = 9), and aged (n = 10) New Zealand White rabbits were utilized in this study. After sacrifice, lens suture patterns were photographed using a stereo surgical dissecting microscope.

Optical dysfunction of the crystalline lens in aquaporin-0-deficient mice.

Aquaporin-0 (AQP0), a water transport channel protein, is the major intrinsic protein (MIP) of lens fiber cell plasma membranes. Mice deficient in the gene for AQP0 (Aqp0, Mip) were generated from a library of gene trap embryo stem cells. Sequence analysis showed that the gene trap vector had inserted into the first exon of Aqp0, causing a null mutation as verified by RNA blotting and immunochemistry.