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Various Lineages (various + lineage)
Selected AbstractsRudabánya: A late miocene subtropical swamp deposit with evidence of the origin of the African apes and humansEVOLUTIONARY ANTHROPOLOGY, Issue 2 2002László Kordos Abstract Rudabánya, a rich late Miocene fossil site in northern central Hungary, has yielded an abundant record of fossil primates, including the primitive catarrhine Anapithecus and the early great ape Dryopithecus. While the affinities of Anapithecus are not clear, Dryopithecus is clearly a great ape sharing numerous characteristics of its dental, cranial and postcranial anatomy with living great apes. Like all Miocene hominids (great apes and humans), Dryopithecus is more primitive in a number of ways than any living hominid, which is probably related to the passage of time since the divergence of the various lineages of living hominids, allowing for similar refinements in morphology and adaptation to take place independently. On the other hand, Dryopithecus (and Ouranopithecus) share derived characters with hominines (African apes and humans), and Sivapithecus (and Ankarapithecus) share derived characters with orangutans, thus dating the split between pongines and hominines to a time before the evolution of these fossil great apes. Pongines and hominines follow similar fates in the late Miocene, the pongines moving south into Southeast Asia from southern or eastern Asia and the hominines moving south into East Africa from the Mediterranean region, between 6 to 9 Ma. [source] Generation of mice harboring a Sox6 conditional null allele,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 5 2006Bogdan Dumitriu Abstract Sox6 belongs to the family of Sry-related HMG box transcription factors, which determine cell fate and differentiation in various lineages. Sox6 is expressed in several tissues, including cartilage, testis, neuronal, and erythropoietic tissues. Mice lacking Sox6 have revealed critical roles for Sox6 in several of these tissues, but their multiple defects and early lethality has limited studies in specific cell types and in postnatal mice. We show here that we have generated mice harboring a Sox6 conditional null allele (Sox6fl+) by flanking the second coding exon with loxP sites. This allele encodes wildtype Sox6 protein, is expressed normally, and is efficiently converted into a null allele (Sox6fl,) by Cre-mediated recombination in somatic and germ cells. Sox6fl+/fl+ mice are indistinguishable from wildtype mice, and Sox6fl,/fl, mice from Sox6,/, mice. These Sox6 conditional null mice will thus be valuable for further uncovering the roles of Sox6 in various processes in vivo. genesis 44:219,224, 2006. Published 2006 Wiley-Liss, Inc. [source] Cadherins in neural crest cell development and transformationJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2001Patrick Pla Cadherins constitute a superfamily of cell adhesion molecules involved in cell-cell interaction, histogenesis and cellular transformation. They have been implicated in the development of various lineages, including derivatives of the neural crest. Neural crest cells (NCC) emerge from the dorsal part of the neural tube after an epithelio-mesenchymal transition (EMT) and migrate through the embryo. After homing and differentiation, NCC give rise to many cell types, such as neurons, Schwann cells and melanocytes. During these steps, the pattern of expression of the various cadherins studied is very dynamic. Cadherins also display plasticity of expression during the transformation of neural crest cell derivatives. Here, we review the pattern of expression and the role of the main cadherins involved in the development and transformation of neural crest cell derivatives. © 2001 Wiley-Liss, Inc. [source] Evolution of the spermatozoon in muroid rodentsJOURNAL OF MORPHOLOGY, Issue 3 2005William G. Breed Abstract In the rodent superfamily Muroidea, a model for the evolution of sperm form has been proposed in which it is suggested that a hook-shaped sperm head and long tail evolved from a more simple, nonhooked head and short tail in several different subfamilies. To test this model the shape of the sperm head, with particular emphasis on its apical region, and length of sperm tail were matched to a recent phylogeny based on the nucleotide sequence of several protein-coding nuclear genes from 3 families and 10 subfamilies of muroid rodents. Data from the two other myomorph superfamilies, the Dipodoidea and kangaroo rats in the Geomyoidea, were used for an outgroup comparison. In most species in all 10 muroid subfamilies, apart from in the Murinae, the sperm head has a long rostral hook largely composed of acrosomal material, although its length and cross-sectional shape vary across the various subfamilies. Nevertheless, in a few species of various lineages a very different sperm morphology occurs in which an apical hook is lacking. In the outgroups the three species of dipodid rodents have a sperm head that lacks a hook, whereas in the heteromyids an acrosome-containing apical hook is present. It is concluded that, as the hook-shaped sperm head and long sperm tail occur across the muroid subfamilies, as well as in the heteromyid rodents, it is likely to be the ancestral condition within each of the subfamilies with the various forms of nonhooked sperm heads, that are sometimes associated with short tails, being highly derived states. These findings thus argue against a repeated evolution in various muroid lineages of a complex, hook-shaped sperm head and long sperm tail from a more simple, nonhooked sperm head and short tail. An alternative proposal for the evolution of sperm form within the Muroidea is presented in the light of these data. J. Morphol. © 2005 Wiley- Liss, Inc. [source] Phylogenetic relationships of the spider family Tetragnathidae (Araneae, Araneoidea) based on morphological and DNA sequence dataCLADISTICS, Issue 2 2009Fernando Álvarez-Padilla The monophyly of Tetragnathidae including the species composition of the family (e.g., Are Nephila and their relatives part of this lineage?), the phylogenetic relationships of its various lineages, and the exact placement of Tetragnathidae within Araneoidea have been three recalcitrant problems in spider systematics. Most studies on tetragnathid phylogeny have focused on morphological and behavioral data, but little molecular work has been published to date. To address these issues we combine previous morphological and behavioral data with novel molecular data including nuclear ribosomal RNA genes 18S and 28S, mitochondrial ribosomal RNA genes 12S and 16S and protein-coding genes from the mitochondrion [cytochrome c oxidase subunit I (COI)] and from the nucleus (histone H3), totaling ca. 6.3 kb of sequence data per taxon. These data were analyzed using direct optimization and static homology using both parsimony and Bayesian methods. Our results indicate monophyly of Tetragnathidae, Tetragnathinae, Leucauginae, the "Nanometa clade" and the subfamily Metainae, which, with the exception of the later subfamily, received high nodal support. Morphological synapomorphies that support these clades are also discussed. The position of tetragnathids with respect to the rest of the araneoid spiders remains largely unresolved but tetragnathids and nephilids were never recovered as sister taxa. The combined dataset suggests that Nephilidae is sister to Araneidae; furthermore, the sister group of Nephila is the clade composed by Herennia plus Nephilengys and this pattern has clear implications for understanding the comparative biology of the group. Tetragnathidae is most likely sister to some members of the "reduced piriform clade" and nephilids constitute the most-basal lineage of araneids. [source] Immunostimulatory Effects of Mesenchymal Stem Cell-Derived Neurons: Implications for Stem Cell Therapy in Allogeneic TransplantationsCLINICAL AND TRANSLATIONAL SCIENCE, Issue 1 2008Marianne D. Castillo Abstract Mesenchymal stem cells (MSCs) differentiate along various lineages to specialized mesodermal cells and also transdifferentiate into cells such as ectodermal neurons. MSCs are among the leading adult stem cells for application in regenerative medicine. Advantages include their immune-suppressive properties and reduced ethical concerns. MSCs also show immune-enhancing functions. Major histocompatibility complex II (MHC-II) is expected to be downregulated in MSCs during neurogenesis. Ideally, "off the shelf" MSCs would be suited for rapid delivery into patients. The question is whether these MSC-derived neurons can reexpress MHC-II in a milieu of inflammation. Western analyses demonstrated gradual decrease in MHC-II during neurogenesis, which correlated with the expression of nuclear CIITA, the master regulator of MHC-II expression. MHC-II expression was reversed by exogenous IFNY. One-way mixed lymphocyte reaction with partly differentiated neurons showed a stimulatory effect, which was partly explained by the release of the proinflammatory neurotransmitter substance P (SP), cytokines, and decreases in miR-130a and miR-206. The anti-inflammatory neurotransmitters VIP and CGRP were decreased at the peak time of immune stimulation. In summary, MSC-derived neurons show decreased MHC-II expression, which could be reexpressed by IFNY. The release of neurotransmitters could be involved in initiating inflammation, underscoring the relevance of immune responses as consideration for stem cell therapies. [source] | ||||||||||