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General Morphology (general + morphology)
Selected AbstractsULTRASTRUCTURE AND LSU rDNA,BASED REVISION OF PERIDINIUM GROUP PALATINUM (DINOPHYCEAE) WITH THE DESCRIPTION OF PALATINUS GEN.JOURNAL OF PHYCOLOGY, Issue 5 2009The name Peridinium palatinum Lauterborn currently designates a freshwater peridinioid with 13 epithecal and six cingular plates, and no apical pore complex. Freshwater dinoflagellate floras classify it in Peridinium group palatinum together with P. pseudolaeve M. Lefčvre. General ultrastructure, flagellar apparatus, and pusular components of P. palatinum were examined by serial section TEM and compared to P. cinctum (O. F. Müll.) Ehrenb. and Peridiniopsis borgei Lemmerm., respectively, types of Peridinium and Peridiniopsis. Partial LSU rDNA sequences from P. palatinum, P. pseudolaeve and several peridinioids, woloszynskioids, gymnodinioids, and other dinoflagellates were used for a phylogenetic analysis. General morphology and tabulation of taxa in group palatinum were characterized by SEM. Differences in plate numbers, affecting both the epitheca and the cingulum, combine with differences in plate ornamentation and a suite of internal cell features to suggest a generic-level distinction between Peridinium group palatinum and typical Peridinium. The branching pattern of the phylogenetic tree is compatible with this conclusion, although with low support from bootstrap values and posterior probabilities, as are sequence divergences estimated between species in group palatinum, and typical Peridinium and Peridiniopsis. Palatinus nov. gen. is proposed with the new combinations Palatinus apiculatus nov. comb. (type species; syn. Peridinium palatinum), P. apiculatus var. laevis nov. comb., and P. pseudolaevis nov. comb. Distinctive characters for Palatinus include a smooth or slightly granulate, but not areolate, plate surface, a large central pyrenoid penetrated by cytoplasmic channels and radiating into chloroplast lobes, and the presence of a peduncle-homologous microtubular strand. Palatinus cells exit the theca through the antapical-postcingular area. [source] Gross anatomy of the musculature and a new description of the reproductive system of Tanaisia bragai and Tanaisia inopina (Trematoda: Eucotylidae) analysed by confocal laser scanning microscopyACTA ZOOLOGICA, Issue 2 2010Sthefane D'ávila Abstract D'ávila, S., Manso, P. P. A., Bessa, E. C. A., Rodrigues, M. L. A. and Dias, R. J. P. 2010. Gross anatomy of the musculature and a new description of the reproductive system of Tanaisia bragai and Tanaisia inopina (Trematoda: Eucotylidae) analysed by confocal laser scanning microscopy. ,Acta Zoologica (Stockholm) 91: 139,149 Confocal scanning laser microscopy has become an important tool to clarify the organization of the musculature and innervation, as well as the morphology of the reproductive and alimentary tract of various helminth species. The goal of this work was to describe the morphology of the reproductive system and the gross anatomy of the musculature of adults of the species Tanaisia bragai and Tanaisia inopina by means of confocal scanning laser microscopy. The helminths were found parasitizing the kidney collection ducts of Columba livia, in the municipality of Juiz de Fora, Brazil. These helminths were stained with Mayer's carmalum, mounted on permanent slides and observed through a confocal scanning laser microscope. The tomographic images showed the morphology of the organs and glands of the reproductive system, along with the general morphology of the musculature of the body wall, oral sucker, acetabulum, pharynx, intestinal caeca, oesophagus and reproductive system ducts. The present work is the first re-characterization of the reproductive tract of T. bragai and T. inopina. We also present the first description of the general morphology of the gametes and cells of the glands associated with the reproductive apparatus of these species. [source] Developmental morphology of the neonatal alligator (Alligator mississippiensis) ovaryJOURNAL OF MORPHOLOGY, Issue 3 2008Brandon C. Moore Abstract American alligator (Alligator mississippiensis) ovary development is incomplete at hatching. During the months following hatching, the cortical processes of oogenesis started in ovo continues and folliculogenesis is initiated. Additionally, the medullary region of the gonad undergoes dramatic restructuring. We describe alligator ovarian histology at hatching, 1 week, 1 month, and 3 months of age in order to characterize the timing of morphological development and compare these findings to chicken ovary development. At hatching, the ovarian cortex presents a germinal epithelium containing oogonia and a few primary oocytes irregularly scattered between somatic epithelial cells. The hatchling medulla shows fragmentation indicative of the formation of lacunae. By 1 week of age, oocytes form growing nests and show increased interactions with somatic cells, indicative of the initiation of folliculogenesis. Medullary lacunae increase in diameter and contain secretory material in their lumen. At 1 month, nest sizes and lacunar diameters continue to enlarge. Pachytene oocytes surrounded by somatic cells are more frequent. Trabeculae composed of dense irregular connective tissue divide cortical nests. Three months after hatching oocytes in meiotic stages of prophase I up to diplotene are present. The ovary displays many enlarged follicles with oocytes in diplotene arrest, thecal layers, lampbrush chromosomes, and complete layers of follicular cells. The medulla is an elaborated complex of vascularized lacunae underlying the cortex and often containing discrete lymphoid aggregates. While the general morphology of the alligator ovary is similar to that of the chicken ovary, the progression of oogenesis and folliculogenesis around hatching is notably slower in alligators. Diplotene oocytes are observed at hatching in chickens, but not until 3 months in alligators. Folliculogenesis is completed at 3 weeks in chickens whereas it is still progressing at 3 months in alligators. J. Morphol., 2008. © 2007 Wiley-Liss, Inc. [source] Fine structure and development of the retina of the grenadier anchovy Coilia nasus (Engraulididae, Clupeiformes)JOURNAL OF MORPHOLOGY, Issue 1 2001Christoph Haacke Abstract A study of the morphogenesis of the grenadier anchovy retina was undertaken using light and electron microscopy. Five developmental stages from prelarvae 3 days after fertilization to adult fish were studied. In addition to the general morphology of the eye and retina, special emphasis was given to the development of the photoreceptors and pigment epithelium (PE). The earliest retinae showing structural features indicative of a functioning eye are pure cone retinae composed of rows of alternating long and short cones forming a transient, tesselated pattern. At this stage there is a conventional PE containing melanin. In older stages cone rows are separated by the newly formed rods and by PE wedges filled with diffusely reflecting guanine crystallites. The findings are compared with the retinae of other engraulidids and with the development of teleost retinae in general. Moreover, the observed structural changes are discussed with respect to the photic habitat conditions of these anadromous fish that move between coastal waters, estuary, and river. J. Morphol. 248:41,55, 2001. © 2001 Wiley-Liss, Inc. [source] DESCRIPTION OF A NEW GENUS OF PFIESTERIA -LIKE DINOFLAGELLATE, LUCIELLA GEN.JOURNAL OF PHYCOLOGY, Issue 4 2007INCLUDING TWO NEW SPECIES: LUCIELLA MASANENSIS SP., NOV. (DINOPHYCEAE) A new genus of Pfiesteria -like heterotrophic dinoflagellate, Luciella gen. nov., and two new species, Luciella masanensis sp. nov. and Luciella atlantis sp. nov., are described. These species commonly occur with other small (<20 ,m) heterotrophic and mixotrophic dinoflagellates in estuaries from Florida to Maryland and the southern coast of Korea, suggesting a possible global distribution. An SEM analysis indicates that members of the genus Luciella have the enhanced Kofoidian plate formula of Po, cp, X, 4,, 2a, 6,, 6c, PC, 5+s, 5,, 0p, and 2,,. The two four-sided anterior intercalary plates are diamond shaped. The genus Luciella differs from the other genera in the Pfiesteriaceae by a least one plate in the plate tabulation and in the configuration of the two anterior intercalary plates. An SSU rDNA phylogenetic analysis confirmed the genus as monophyletic and distinct from the other genera in the Pfiesteriaceae. The morphology of Luciella masanensis closely resembles Pfiesteria piscicida Steid. et J. M. Burkh. and other Pfiesteria -like dinoflagellates in size and shape, making it easily misidentified using LM. Luciella atlantis, in contrast, has a more distinctive morphology. It can be distinguished from L. masanensis and other Pfiesteria -like organisms by a larger cell size, a more conical-shaped epitheca and hypotheca, larger rhombic-shaped intercalary plates, and an asymmetrical hypotheca. The genus Luciella is assigned to the order Peridiniales and the family Pfiesteriaceae based on plate tabulation, plate pattern, general morphology, and phylogenetic analysis. [source] Evolution rampant: house mice on MadeiraMOLECULAR ECOLOGY, Issue 21 2009R. J. BERRY House mice are extra-ordinary animals ,extra -ordinary in the literal sense of that word. They are pests , but also a valued laboratory animal. They are generalized rodents , and successful in habitats from tundra to tropics and from sea-level to high altitudes. They have differentiated into a perplexity of taxa, yet differ little in their general morphology. They were long scorned by ecologists as recently arrived commensals, but are increasingly illuminating evolutionary processes as new techniques are applied to their study. Local forms, once valued only by taxonomists, are proving ever more interesting as their genetics are probed. In 1992, Mathias & Mira described the apparently unexciting characteristics of mice living on the two main islands of the Madeira group, 600 km west of continental Portugal. Then in 2000, Britton-Davidian et al. discovered that there were at least six chromosomal (Robertsonian) races on the main island. In the past decade, studies of molecular and mitochondrial genomes have shown an array of variables and posed questions about the origins and subsequent evolution of these island mice. In this issue of Molecular Ecology, Förster et al. report on the mtDNA haplotypes found on the island and in mainland Portugal, discuss the probable source of the island colonizers, and consider data which might give information about the timing of the colonizing event(s). [source] Cattle Pathogen Tritrichomonas foetus (Riedmüller, 1928) and Pig Commensal Tritrichomonas suis (Gruby & Delafond, 1843) Belong to the Same SpeciesTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2002JAN TACHEZY ABSTRACT. A number of reports suggest that the sexually transmitted pathogen of cattle, Tritrichomonas foetus, and a gastrointestinal commensal of pigs, Tritrichomonas suis, are very similar and may be co-specific. A conclusive review of the taxonomic and nomenclatural status of these species has not been presented so far. Toward this end, we reexamined and compared porcine and bovine trichomonads with regard to their morphology, pathogenic potential, and DNA polymorphism. Using light and electron microscopy, no distinguishing features between T. foetus and T. suis strains were found in size, general morphology, and karyomastigont structure. Both bovine and porcine trichomonads showed pathogenic potential in the subcutaneous mouse assays and did not separate into distinct groups according to strain virulence. Three DNA fingerprinting methods (i.e. RFLP, RAPD, and PCR-based analysis of variable-length DNA repeats) that produce species-specific DNA fragment patterns did not distinguish between the bovine and porcine strains. Sequencing of a variable 502-bp DNA fragment as well as comparison of 16S rRNA gene sequences did not reveal species-specific differences between the cattle and porcine strains. Therefore, we conclude that T. foetus and T. suis belong to the same species. To prevent confusion that may arise from T. foetus-T. suis synonymy, we propose to suppress the older name suis and maintain its accustomed junior synonym foetus as a nomen protection for both cattle and porcine trichomonads. The case has been submitted to the International Commision on Zoological Nomenclature for ruling under its plenary power. [source] Interaction of radio jets with clouds in the ambient medium: Numerical simulationsASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009S. JeyakumarArticle first published online: 13 FEB 200 Abstract Hydrodynamical simulations of jets interacting with clouds moving in the ambient medium of the host galaxy are presented. Clouds with sizes of the order of the jet diameter and smaller, crossing the path of the jet with different speeds are considered. In the case of slow moving clouds the jet is stopped over the brief period of time taken by the cloud to cross the jet. The jet maintains its general morphology in the case of fast moving clouds. Erosion of the clouds leads to redistribution of cloud material to large distances. Such interaction may explain the large outflow velocities observed from pc to kpc scales in the compact radio sources (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A review of the thoracic splanchnic nerves and celiac gangliaCLINICAL ANATOMY, Issue 5 2010Marios Loukas Abstract Anatomical variation of the thoracic splanchnic nerves is as diverse as any structure in the body. Thoracic splanchnic nerves are derived from medial branches of the lower seven thoracic sympathetic ganglia, with the greater splanchnic nerve comprising the more cranial contributions, the lesser the middle branches, and the least splanchnic nerve usually T11 and/or T12. Much of the early anatomical research of the thoracic splanchnic nerves revolved around elucidating the nerve root level contributing to each of these nerves. The celiac plexus is a major interchange for autonomic fibers, receiving many of the thoracic splanchnic nerve fibers as they course toward the organs of the abdomen. The location of the celiac ganglia are usually described in relation to surrounding structures, and also show variation in size and general morphology. Clinically, the thoracic splanchnic nerves and celiac ganglia play a major role in pain management for upper abdominal disorders, particularly chronic pancreatitis and pancreatic cancer. Splanchnicectomy has been a treatment option since Mallet-Guy became a major proponent of the procedure in the 1940s. Splanchnic nerve dissection and thermocoagulation are two common derivatives of splanchnicectomy that are commonly used today. Celiac plexus block is also a treatment option to compliment splanchnicectomy in pain management. Endoscopic ultrasonography (EUS)-guided celiac injection and percutaneous methods of celiac plexus block have been heavily studied and are two important methods used today. For both splanchnicectomies and celiac plexus block, the innovation of ultrasonographic imaging technology has improved efficacy and accuracy of these procedures and continues to make pain management for these diseases more successful. Clin. Anat. 23:512,522, 2010. © 2010 Wiley-Liss, Inc. [source] | ||||||||||