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Dorsal Region (dorsal + region)
Selected AbstractsSecond lineage of heart forming region provides new understanding of conotruncal heart defectsCONGENITAL ANOMALIES, Issue 1 2010Yuji Nakajima ABSTRACT Abnormal heart development causes various congenital heart defects. Recent cardiovascular biology studies have elucidated the morphological mechanisms involved in normal and abnormal heart development. The primitive heart tube originates from the lateral-most part of the heart forming mesoderm and mainly gives rise to the left ventricle. Then, during the cardiac looping, the outflow tract is elongated by the addition of cardiogenic cells from the both pharyngeal and splanchnic mesoderm (corresponding to anterior and secondary heart field, respectively), which originate from the mediocaudal region of the heart forming mesoderm and are later located anteriorly (rostrally) to the dorsal region of the heart tube. Therefore, the heart progenitors that contribute to the outflow tract region are distinct from those that form the left ventricle. The knowledge that there are two different lineages of heart progenitors in the four-chambered heart provides new understanding of the morphological and molecular etiology of conotruncal heart defects. [source] Local activation of protein kinase A inhibits morphogenetic movements during Xenopus gastrulationDEVELOPMENTAL DYNAMICS, Issue 1 2003Byung-Ho Song Abstract cAMP-dependent protein kinase (PKA) has various biological roles in many organisms. However, little is known about its role in the developmental processes of vertebrates. In this study, we describe the functional analysis of PKA during gastrulation movements in Xenopus laevis. Overexpression of constitutively active PKA (cPKA) in the dorsal equatorial region of the embryo affects morphogenetic movement during gastrulation. We also show that intrinsic differences of PKA activities along the dorsoventral axis are set up and the level of PKA activity on the dorsal region is lower than that on the ventral region from late blastula to gastrula stages. In addition, PKA activation in animal explants inhibits activin-induced elongation. In cPKA-injected embryos, there were no changes in the expressions of markers involved in mesoderm specification, although the correct expression domains of these genes were altered. The effects of PKA activation can be restored by coexpression of PKI, a pseudosubstrate of PKA. We further analyzed the effects of PKA activation on the behavior of migratory gastrulating cells in vitro. Expression of cPKA in head mesoderm cells causes less polarized and/or randomized migration as demonstrated by a directional cell migration assay. Finally, we show that RhoA GTPase lies downstream of PKA, affecting activin-induced convergent extension movements. Taken together, these results suggest that overexpressed PKA can modulate a pathway responsible for morphogenetic movements during Xenopus gastrulation. Developmental Dynamics 227:91,103, 2003. © 2003 Wiley-Liss, Inc. [source] Muscle thickness and neuron density in the caecum of horses with chronic recurrent caecal impactionEQUINE VETERINARY JOURNAL, Issue S32 2000G. F. SCHUSSER Summary In this study, the hypothesis that caecal smooth muscle layers would be thinner and the linear neuron density of myenteric plexus greater was tested in normal horses compared to those with chronic recurrent caecal impaction. Four normal horses and 18 horses with chronic recurrent caecal impaction were subjected to euthanasia and 7 tissue samples were collected from each horse at different regions of the caecum (apex, dorsal body, cranial base, dorsal base, caudal base, caudal body, ventral body). Twelve horses with chronic recurrent caecal impaction were treated surgically. Only one tissue sample of the cranial part of the caecal base close to the caecocolic orifice was taken during surgery. The thickness of the circular muscle layer of all caecal regions measured in killed horses with chronic recurrent caecal impaction was significantly increased compared to the equivalent caecal region of normal horses. On the other hand, the longitudinal muscle layer was significantly thicker only in the cranial and caudal caecal base and in the dorsal region of the caecal body. The linear neuron densities of all caecal base areas and 2 caecal body regions, the caudal body region and of the apex, of killed horses with chronic recurrent caecal impaction were significantly lower compared with those in clinically normal horses. The circular muscle layer of all caecal regions was thickened (hypertrophied) probably as a consequence of chronic uncoordinated hypercontractility due to neuron deficit in the myenteric plexus of the caecal base. [source] cDNA cloning and characterization of a novel calmodulin-like protein from pearl oyster Pinctada fucataFEBS JOURNAL, Issue 19 2005Shuo Li Calcium metabolism in oysters is a very complicated and highly controlled physiological and biochemical process. However, the regulation of calcium metabolism in oyster is poorly understood. Our previous study showed that calmodulin (CaM) seemed to play a regulatory role in the process of oyster calcium metabolism. In this study, a full-length cDNA encoding a novel calmodulin-like protein (CaLP) with a long C-terminal sequence was identified from pearl oyster Pinctada fucata, expressed in Escherichia coli and characterized in vitro. The oyster CaLP mRNA was expressed in all tissues tested, with the highest levels in the mantle that is a key organ involved in calcium secretion. In situ hybridization analysis reveals that CaLP mRNA is expressed strongly in the outer and inner epithelial cells of the inner fold, the outer epithelial cells of the middle fold, and the dorsal region of the mantle. The oyster CaLP protein, with four putative Ca2+ -binding domains, is highly heat-stable and has a potentially high affinity for calcium. CaLP also displays typical Ca2+ -dependent electrophoretic shift, Ca2+ -binding activity and significant Ca2+ -induced conformational changes. Ca2+ -dependent affinity chromatography analysis demonstrated that oyster CaLP was able to interact with some different target proteins from those of oyster CaM in the mantle and the gill. In summary, our results have demonstrated that the oyster CaLP is a novel member of the CaM superfamily, and suggest that the oyster CaLP protein might play a different role from CaM in the regulation of oyster calcium metabolism. [source] Neural correlates of noncanonical syntactic processing revealed by a picture-sentence matching taskHUMAN BRAIN MAPPING, Issue 9 2008Ryuta Kinno Abstract It remains controversial whether the left inferior frontal gyrus subserves syntactic processing or short-term memory demands. Here we devised a novel picture-sentence matching task involving Japanese sentences with different structures to clearly contrast syntactic reanalysis processes. Using event-related functional magnetic resonance imaging (fMRI), activations under three main conditions were directly compared: a canonical/subject-initial active sentence (AS), a noncanonical/subject-initial passive sentence (PS), and a noncanonical/object-initial scrambled sentence (SS). We found that activation in the dorsal region of the left inferior frontal gyrus (dF3t) was enhanced more by the noncanonical processing under the PS and SS conditions than by the canonical processing under the AS condition, and this enhancement was independent of domain-general factors, such as general memory demands and task difficulty. Moreover, the left posterior superior/middle temporal gyrus (pSTG/MTG) showed more enhanced responses to object-initial sentences under the SS condition than to subject-initial sentences under the AS and PS conditions, which were not significantly affected by task difficulty. Furthermore, activation in the left lateral premotor cortex (LPMC) increased under the AS, PS, and SS conditions, in that order. It is possible that task difficulty affects the left LPMC, but the three distinct activations patterns suggest that these frontal and temporal regions work in concert to process syntactic structures, with their respective contributions dynamically regulated by linguistic requirements. Hum Brain Mapp 2008. © 2007 Wiley-Liss, Inc. [source] A histo-morphological study of the testis of the sharptooth catfish (Clarias gariepinus) as reference for future toxicological assessmentsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2008J. C. Van Dyk Summary The sharptooth catfish (Clarias gariepinus) has recently been shown to be a useful indicator species of oestrogen polluted waters in South Africa (Barnhoorn et al., 2004). Knowledge of the normal reproductive biology of this species is important to be able to assess the morphological changes caused by the exposure to potentially harmful toxicants including endocrine disruptor chemicals (EDCs). Eleven sexually mature C. gariepinus males were selected from an aquarium population bred through hormone induced spawning in reconstituted reverse osmosis water. The fish were reared under controlled conditions averting exposure to potentially EDCs and allowing the description of the normal testis histomorphology of unexposed healthy specimens. The testes of C. gariepinus are paired elongated organs situated in the dorsal region of the visceral cavity. Histologically, the testes possess a lobular organization enclosed by a thin tunica albuginea. Depending on the tissue region, each seminiferous lobule contains some or all of the various developmental stages of spermatogenesis including a single primary spermatogonia, groups of secondary spermatogonia, cysts of primary and secondary spermatocytes, spermatids, and spermatozoa. Nutritive Sertoli cells are visible on the periphery of the seminiferous lobules. Interstitial tissue (including groups of Leydig cells) and blood vessels constitute most of the interlobular space. It is expected that the histological results of this study will contribute to a currently limited, but growing gonadal histological database for southern African freshwater fish species to serve as reference in future toxicity assessments. [source] Reduced swimming abilities in fast-growing transgenic common carp Cyprinus carpio associated with their morphological variationsJOURNAL OF FISH BIOLOGY, Issue 1 2009D. Li Critical swimming speeds (Ucrit) and morphological characters were compared between the F4 generation of GH-transgenic common carp Cyprinus carpio and the non-transgenic controls. Transgenic fish displayed a mean absolute Ucrit value 22·3% lower than the controls. Principal component analysis identified variations in body shape, with transgenic fish having significantly deeper head, longer caudal length of the dorsal region, longer standard length (LS) and shallower body and caudal region, and shorter caudal length of the ventral region. Swimming speeds were related to the combination of deeper body and caudal region, longer caudal length of the ventral region, shallower head depth, shorter caudal length of dorsal region and LS. These findings suggest that morphological variations which are poorly suited to produce maximum thrust and minimum drag in GH-transgenic C. carpio may be responsible for their lower swimming abilities in comparison with non-transgenic controls. [source] Conservation and diversification of the symmetry developmental program among close relatives of snapdragon with divergent floral morphologiesNEW PHYTOLOGIST, Issue 3 2009Jill C. Preston Summary ,,Multiple evolutionary shifts in floral symmetry and stamen number have occurred in the snapdragon (Antirrhinum majus) family Veronicaceae. In Mohavea, Veronica and Gratiola there have been independent evolutionary reductions in stamen number and modifications to corolla shape. It is hypothesized that changes in the regulation of homologs of snapdragon dorsal flower identity genes CYCLOIDEA (CYC) and RADIALIS (RAD) underlie these floral transitions. ,,CYC -like and RAD -like genes from Veronica montana and Gratiola officinalis were cloned and sequenced, compared with homologs from other Veronicaceae species using phylogenetic analysis, and their expression was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization. ,,VmCYC1, GoCYC1, GoCYC2 and RAD -like genes are expressed exclusively in the dorsal region of floral meristems and developing flowers. Their expression patterns do not correlate with patterns of stamen arrest. VmCYC2 and GoCYC3 are expressed in both vegetative and floral tissues, with VmCYC2 being most abundant in all regions of the floral meristem and all petals. ,,These results support conservation of the floral symmetry gene network for Veronicaceae RAD -like and some CYC -like paralogs, suggest regulatory evolution of other CYC -like genes following gene duplication and implicate different genetic mechanisms underlying dorsal versus ventral stamen abortion within Veronica and Gratiola. [source] Hypoandrogenism related to early skin wound healing resistance in ratsANDROLOGIA, Issue 2 2010A. Petroianu Summary The purpose of this study was to verify the effect of testosterone depletion on healing of surgical skin wounds at different ages and post-operative periods. Forty-four Wistar male rats were divided into four groups: Group 1Y (n = 11) , young control, sham-operated rats (30-day old); Group 1A (n = 10) , adult control, sham-operated rats (3 to 4-month old); Group 2Y (n = 10) , young rats after bilateral orchiectomy; and Group 2A (n = 11) , adult rats after bilateral orchiectomy. After 6 months, a linear incision was performed on the dorsal region of the animals. The resistance of the wound healing was measured in a skin fragment using a tensiometer, on the 7th and 21st post-operative days. The wound healing resistance was higher in Group 1Y than in Group 2Y after 7 days (P < 0.05). Wound healing resistance at 21 days was higher than at 7 days in all groups (P < 0.05). Late wound healing resistance was not different between young and adult rats. It is concluded that bilateral orchiectomy diminished the wound healing resistance only in young animals at the 7th post-operative day. [source] | ||||||||||||||||