A Comparative 2-Dimensional Gel Protein Database of the Intact and Regenerating Newt Limbs

In this paper we describe a two-dimensional gel database of the regenerating newt limb. Protein synthesis was compared in the intact limb, in the 1-week regenerating limb, representing the dedifferentiation stage, and in the 2-week regenerating limb, representing the formation of the blastema. This comparative database provided data on differential expression of about 800 proteins during the process of limb regeneration. In addition, a map has been generated for these proteins for future guidance in characterizing further new, unknown proteins. The overall expression patterns of the proteins indicated that the dedifferentiation stage was marked by down-regulation of most proteins, while the blastema formation was marked by the appearance of many new proteins. The potential use of such a database in isolating factors involved during limb regeneration is discussed

Patterns of Gene Expression in Microarrays and Expressed Sequence Tags from Normal and Cataractous Lenses

In this contribution, we have examined the patterns of gene expression in normal and cataractous lenses as presented in five different papers using microarrays and expressed sequence tags. The purpose was to evaluate unique and common patterns of gene expression during development, aging and cataracts

Identification of MicroRNAs and Other Small RNAs from the Adult Newt Eye

MicroRNAs (miRNAs) are capable of controlling gene expression by targeting complimentary sequences in many mRNAs. Thus, a small number of miRNAs are capable of regulating expression of many different genes. miRNAs have been found in all animals from Drosophila to human and they are highly conserved. This work was undertaken in order to identify such RNAs in the newt eye

The Future of Carbon-Based Scaffolds in Foot and Ankle Surgery

Autologous grafts have been the gold standard in tissue replacement and the most accurate means of recapitulating both the biological and mechanical properties of tissue. However, autologous grafts have had complications and drawbacks. Skin grafting, a prime example of an autologous tissue graft, has been limited by the size of graft, availability, and secondary donor site morbidity. Use of cadaveric tissues circumvents several limitations of autologous grafts; however, sterilization processes used to reduce the risk of disease transmission potentially weaken tissues and eliminate living cells and some growth factors from scaffolds, making them suboptimal tissue replacements. Chemical cross-linkage of tissue scaffolds has been used in some circumstances to strengthen weak tissues, but can result in a prolonged inflammatory response and limit graft integration in vivo. Partial enzymatic digestion of cadaveric tissues has also been used to improve graft porosity, which potentially assists with graft neovascularization, although this procedure has not been overwhelmingly successful. Proprietary methods of chemically and physically stripping tissues of cellular materials have been commercially developed to minimize graft rejection and loss of essential biological factors; however, these methods cannot be universally applied to all tissues. GraftJacket Matrix (GJ) (Wright Medical, Arlington, TN, USA), an acellular human dermis–derived graft, is an example of a commercially available graft that is commonly used in surgery for soft-tissue augmentation and repair. The elastic properties of skin-derived scaffolds make GJ an inferior replacement for stiffer tissues such as tendon. Hence, current limitations in tissue processing have spawned interest in emerging technologies that enable precise engineering and manufacturing of scaffold materials on a nanoscale that recapitulate the unique mechanical needs of a variety of tissues while promoting tissue repair that also occurs on a nanoscale

A Novel Approach to Control Growth, Orientation, and Shape of Human Osteoblasts

Carbon-based materials are considered to be promising materials as implants because of their unique mechanical and biocompatibility properties. The current paper investigates the use of carbon-based materials as a functional interface for tissue scaffolds and medical implants. Three basic parameters were explored such as graphene orientation, crystallinity and surface interaction. To explore the effect of the orientation, samples were made with and without a preferred carbon orientation. Conversely, the crystallinity was studied using graphitic and carbonaceous matrices. Fluorescent, confocal and environmental scanning microscopy was used to visualize cell response. The cell attachment, proliferation and elongation were prevalent on the unidirectional carbon preform. It seems that the cells tended to orient parallel to the fiber axis (i.e. parallel to the 002 graphene plane) and proliferate as a function of higher crystallinity. In conclusion, the osteoblast (the bone-forming cells) attachment and growth rate is a function of carbon structure, more specifically, the crystallite size, graphene orientation and carbon graphitizability

A System for Culturing Iris Pigment Epithelial Cells to Study Lens Regeneration in Newt

Salamanders like newt and axolotl possess the ability to regenerate many of its lost body parts such as limbs, the tail with spinal cord, eye, brain, heart, the jaw 1. Specifically, newts are unique for its lens regeneration capability. Upon lens removal, IPE cells of the dorsal iris transdifferentiate to lens cells and eventually form a new lens in about a month 2,3. This property of regeneration is never exhibited by the ventral iris cells. The regeneration potential of the iris cells can be studied by making transplants of the in vitro cultured IPE cells. For the culture, the dorsal and ventral iris cells are first isolated from the eye and cultured separately for a time period of 2 weeks (Figure 1). These cultured cells are reaggregated and implanted back to the newt eye. Past studies have shown that the dorsal reaggregate maintains its lens forming capacity whereas the ventral aggregate does not form a lens, recapitulating, thus the in vivo process (Figure 2) 4,5. This system of determining regeneration potential of dorsal and ventral iris cells is very useful in studying the role of genes and proteins involved in lens regeneration

Regeneration of Retinotectal Projections After Optic Tectum Removal in Adult Newts

Purpose: When injured, the adult newt possesses the remarkable capability to regenerate tissues and organs with return of function and physiology. One example is the newt eye, in which regeneration can restore normal vision if the retina or lens has been removed. We wanted to examine how the retinotectal projections regenerate after removal of the brain’s optic tectum and establish this animal as a model for retinal projection as well as a central nervous system regeneration model

Lens Regeneration in Axolotl: New Evidence of Developmental Plasticity

Background: Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration. Frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. The axolotl is another salamander which, like the newt, regenerates its limbs or its tail with the spinal cord, but up until now all reports have shown that it does not regenerate the lens

Conservation of the Three-Dimensional Structure in Non-Homologous Or Unrelated Proteins

In this review, we examine examples of conservation of protein structural motifs in unrelated or non-homologous proteins. For this, we have selected three DNA-binding motifs: the histone fold, the helix-turn-helix motif, and the zinc finger, as well as the globin-like fold. We show that indeed similar structures exist in unrelated proteins, strengthening the concept that three-dimensional conservation might be more important than the primary amino acid sequence

A Linkage Map for the Newt \u3cem\u3eNotophthalmus viridescens\u3c/em\u3e: Insights in Vertebrate Genome and Chromosome Evolution

Genetic linkage maps are fundamental resources that enable diverse genetic and genomic approaches, including quantitative trait locus (QTL) analyses and comparative studies of genome evolution. It is straightforward to build linkage maps for species that are amenable to laboratory culture and genetic crossing designs, and that have relatively small genomes and few chromosomes. It is more difficult to generate linkage maps for species that do not meet these criteria. Here, we introduce a method to rapidly build linkage maps for salamanders, which are known for their enormous genome sizes. As proof of principle, we developed a linkage map with thousands of molecular markers (N=2349) for the Eastern newt (Notophthalmus viridescens). The map contains 12 linkage groups (152.3–934.7cM), only one more than the number of chromosome pairs. Importantly, this map was generated using RNA isolated from a single wild caught female and her 28 offspring. We used the map to reveal chromosome-scale conservation of synteny among N. viridescens, A. mexicanum (Urodela), and chicken (Amniota), and to identify large conserved segments between N. viridescens and Xenopus tropicalis (Anura). We also show that met1, a major effect QTL that regulates the expression of alternate metamorphic and paedomorphic modes of development in Ambystoma, associates with a chromosomal fusion that is not found in the N. viridescens map. Our results shed new light on the ancestral amphibian karyotype and reveal specific fusion and translocation events that shaped the genomes of three amphibian model taxa. The ability to rapidly build linkage maps for large salamander genomes will enable genetic and genomic analyses within this important vertebrate group, and more generally, empower comparative studies of vertebrate biology and evolution