Skeletal development in the fossorial gymnophthalmids Calyptommatus sinebrachiatus and Nothobachia ablephara

The development of the cartilaginous and bony elements that form the skull and axial and appendicular skeleton is described in detail for the post-ovipositional embryonic development of the fossorial gymnophthalmid species Calyptommatus sinebrachiatus and Nothobachia ablephara. Both species have a snake-like morphology, showing an elongated body and reduced or absent limbs, as well as modifications in skull bones for burrowing, such as complex articulation surfaces and development of bony extensions that enclose and protect the brain. Similar morphological changes have originated independently in several squamate groups, including the one that led to the snake radiation. This study characterizes the patterns of chondrogenesis and osteogenesis, with special emphasis on the features associated with the burrowing habit, and may be used for future comparative analyses of the developmental patterns involved in the origin of the convergent serpentiform morphologies. (C) 2012 Elsevier GmbH. All rights reserved.

Morphological aspects of the ovaries of turtle Kinosternon scorpioides raised in captivity

Chaves E.P., Oliveira S.C.R., Araujo L.P.F., Oliveira A.S., Miglino M.A., Abreu-Silva A.L., Melo F.A. & Sousa A.L. 2012. Morphological aspects of the ovaries of turtle Kinosternon scorpioides raised in captivity. Pesquisa Veterinaria Brasileira 32(7):667-671. Departamento das Clinicas, Curso de Medicina Veterinaria, Universidade Estadual do Maranhao, Cidade Universitaria Paulo VI, Tirirical, Sao Luis, MA 65050-150, Brazil. E-mail: alana@elo.com.br The swear turtle "jurara" (Kinosternon scorpioides) is a mud turtle of the Amazon region exposed to disordering capture in the rural areas of Maranhao, Brazil. Despite its popularity in these areas, little meaningful information regarding the reproductive morphology is currently available, fact that impedes the adoption of policies for preservation of the species. To obtain more information, we studied the ovarian morphology adult jurara females kept in captivity by morphological and morphometric analysis in the dry and rainy season. The results revealed that all females were sexually mature and were in a vitellogenic period. The ovaries are two irregular structures composed by follicles in different stages of development (primary, secondary and tertiary) scattered in a stroma of loose connective highly vascularized tissue. The ovary weight was 6.25+/-4.23g and 2.27+/-1.42g, for the right and left one respectively. The gonadosomatic indexes were 2.06% for the dry season and 1.79% for the rainy season. The average of the follicles was 29.83 units per ovary. Microscopically, the mature ovaries revealed a basal layer composed by four cellular layers: the inner and outer theca, stratum granulosum with perivitelline membrane and zona radiata with vitelline membrane. No significant differences were observed in the ovaries either in the dry or wet period.

Embryonic development of the fossorial gymnophthalmid lizards Nothobachia ablephara and Calyptommatus sinebrachiatus

The evolutionary history of the lizard family Gymnophthalmidae is characterized by several independent events of morphological modifications to a snake-like body plan, such as limb reduction, body elongation, loss of external ear openings, and modifications in skull bones, as adaptive responses to a burrowing and fossorial lifestyle. The origins of such morphological modifications from an ancestral lizard-like condition can be traced back to evolutionary changes in the developmental processes that coordinate the building of the organism. Thus, the characterization of the embryonic development of gymnophthalmid lizards is an essential step because it lays the foundation for future studies aiming to understand the exact nature of these changes and the developmental mechanisms that could have been responsible for the evolution of a serpentiform (snake-like) from a lacertiform (lizard-like) body form. Here we describe the post-ovipositional embryonic development of the fossorial species Nothobachia ablephara and Calyptommatus sinebrachiatus, presenting a detailed staging system for each one, with special focus on the development of the reduced limbs, and comparing their development to that of other lizard species. The data provided by the staging series are essential for future experimental studies addressing the genetic basis of the evolutionary and developmental variation of the Gymnophthalmidae. (C) 2012 Elsevier GmbH. All rights reserved.

Heterogeneous time-dependent response of adipose tissue during the development of cancer cachexia

Cancer cachexia induces loss of fat mass that accounts for a large part of the dramatic weight loss observed both in humans and in animal models; however, the literature does not provide consistent information regarding the set point of weight loss and how the different visceral adipose tissue depots contribute to this symptom. To evaluate that, 8-week-old male Wistar rats were subcutaneously inoculated with 1 ml (2 x 10(7)) of tumour cells (Walker 256). Samples of different visceral white adipose tissue (WAT) depots were collected at days 0, 4, 7 and 14 and stored at -80 degrees C (seven to ten animals/each day per group). Mesenteric and retroperitoneal depot mass was decreased to the greatest extent on day 14 compared with day 0. Gene and protein expression of PPAR gamma(2) (PPARG) fell significantly following tumour implantation in all three adipose tissue depots while C/EBP alpha (CEBPA) and SREBP-1c (SREBF1) expression decreased over time only in epididymal and retroperitoneal depots. Decreased adipogenic gene expression and morphological disruption of visceral WAT are further supported by the dramatic reduction in mRNA and protein levels of perilipin. Classical markers of inflammation and macrophage infiltration (f4/80, CD68 and MIF-1 alpha) in WAT were significantly increased in the later stage of cachexia (although showing a incremental pattern along the course of cachexia) and presented a depot-specific regulation. These results indicate that impairment in the lipid-storing function of adipose tissue occurs at different times and that the mesenteric adipose tissue is more resistant to the 'fat-reducing effect' than the other visceral depots during cancer cachexia progression. Journal of Endocrinology (2012) 215, 363-373

Morphological records of oocyte maturation in the parthenogenetic tick Amblyomma rotundatum Koch, 1844 (Acari: Ixodidae)

Oocyte maturation in the thelytokous parthenogenetic tick Amblyomma rotundatum was examined for the first time using light and scanning electron microscopy. The panoistic ovary lacks nurse and follicular cells and is a single continuous tubular structure forming a lumen delimited by the ovarian wall. Oocytes of tick species are usually classified according to cytoplasm appearance, the presence of germinal vesicle, the presence of yolk granules, and the chorion. However, for this species, we also use oocyte size as an auxiliary tool since most oocytes were in stages I-Ill and were histologically very similar. Oocytes were classified into five development stages, and specific characteristics were observed: mature oocytes with thin chorion, pedicel cells arranged forming an epithelium with two Or more oocytes attached by the same structure, and a large number of oocytes in the process of reabsorption. (C) 2011 Elsevier GmbH. All rights reserved.

Morphological Alterations in Newly Born Dentate Gyrus Granule Cells That Emerge after Status Epilepticus Contribute to Make Them Less Excitable

Computer simulations of external current stimulations of dentate gyrus granule cells of rats with Status Epilepticus induced by pilocarpine and control rats were used to evaluate whether morphological differences alone between these cells have an impact on their electrophysiological behavior. The cell models were constructed using morphological information from tridimensional reconstructions with Neurolucida software. To evaluate the effect of morphology differences alone, ion channel conductances, densities and distributions over the dendritic trees of dentate gyrus granule cells were the same for all models. External simulated currents were injected in randomly chosen dendrites belonging to one of three different areas of dentate gyrus granule cell molecular layer: inner molecular layer, medial molecular layer and outer molecular layer. Somatic membrane potentials were recorded to determine firing frequencies and inter-spike intervals. The results show that morphologically altered granule cells from pilocarpine-induced epileptic rats are less excitable than control cells, especially when they are stimulated in the inner molecular layer, which is the target area for mossy fibers that sprout after pilocarpine-induced cell degeneration. This suggests that morphological alterations may act as a protective mechanism to allow dentate gyrus granule cells to cope with the increase of stimulation caused by mossy fiber sprouting.

Embryonic and Fetal Development in - Pigmy Rice Rat - Oligoryzomys sp (Rodentia, Sigmodontinae) and its Significance for Being a new Experimental Model

Oligoryzomys (Cricetidae, Sigmodontinae) is a common rodent genus from South America that includes a couple of very similar species. Related species have been used as experimental model for understanding several diseases for which these species are reservoirs. In order to provide a better understanding of the embryological aspects of this group, herein we showed data on the embryonic and fetal development in Oligoryzomys sp. Eight specimens of different stages of gestation were obtained from the Collection of the Zoology Museum of University of Sao Paulo, Brazil. Gestational ages were estimated by crown-rump-length according to Evans and Sack (1973). To address our analysis after examining the gross morphology, tissues from several organs were processed for light and scanning electron microscopy. Morphological data on the systems (nervous system, cardiorespiratory system, intestinal tract and urogenital system) were described in detail. Finally, the findings were compared with what is known about embryological aspects in other rodent species in order to establish similarities and differences during the organogenesis in different species.

When size makes a difference: allometry, life-history and morphological evolution of capuchins (Cebus) and squirrels (Saimiri) monkeys (Cebinae, Platyrrhini)

Abstract Background How are morphological evolution and developmental changes related? This rather old and intriguing question had a substantial boost after the 70s within the framework of heterochrony (changes in rates or timing of development) and nowadays has the potential to make another major leap forward through the combination of approaches: molecular biology, developmental experimentation, comparative systematic studies, geometric morphometrics and quantitative genetics. Here I take an integrated approach combining life-history comparative analyses, classical and geometric morphometrics applied to ontogenetic series to understand changes in size and shape which happen during the evolution of two New World Monkeys (NWM) sister genera. Results Cebus and Saimiri share the same basic allometric patterns in skull traits, a result robust to sexual and ontogenetic variation. If adults of both genera are compared in the same scale (discounting size differences) most differences are small and not statistically significant. These results are consistent using both approaches, classical and geometric Morphometrics. Cebus is a genus characterized by a number of peramorphic traits (adult-like) while Saimiri is a genus with paedomorphic (child like) traits. Yet, the whole clade Cebinae is characterized by a unique combination of very high pre-natal growth rates and relatively slow post-natal growth rates when compared to the rest of the NWM. Morphologically Cebinae can be considered paedomorphic in relation to the other NWM. Geometric morphometrics allows the precise separation of absolute size, shape variation associated with size (allometry), and shape variation non-associated with size. Interestingly, and despite the fact that they were extracted as independent factors (principal components), evolutionary allometry (those differences in allometric shape associated with intergeneric differences) and ontogenetic allometry (differences in allometric shape associated with ontogenetic variation within genus) are correlated within these two genera. Furthermore, morphological differences produced along these two axes are quite similar. Cebus and Saimiri are aligned along the same evolutionary allometry and have parallel ontogenetic allometry trajectories. Conclusion The evolution of these two Platyrrhini monkeys is basically due to a size differentiation (and consequently to shape changes associated with size). Many life-history changes are correlated or may be the causal agents in such evolution, such as delayed on-set of reproduction in Cebus and larger neonates in Saimiri.

Automatic lumen segmentation in IVOCT images using binary morphological reconstruction

Abstract Background Atherosclerosis causes millions of deaths, annually yielding billions in expenses round the world. Intravascular Optical Coherence Tomography (IVOCT) is a medical imaging modality, which displays high resolution images of coronary cross-section. Nonetheless, quantitative information can only be obtained with segmentation; consequently, more adequate diagnostics, therapies and interventions can be provided. Since it is a relatively new modality, many different segmentation methods, available in the literature for other modalities, could be successfully applied to IVOCT images, improving accuracies and uses. Method An automatic lumen segmentation approach, based on Wavelet Transform and Mathematical Morphology, is presented. The methodology is divided into three main parts. First, the preprocessing stage attenuates and enhances undesirable and important information, respectively. Second, in the feature extraction block, wavelet is associated with an adapted version of Otsu threshold; hence, tissue information is discriminated and binarized. Finally, binary morphological reconstruction improves the binary information and constructs the binary lumen object. Results The evaluation was carried out by segmenting 290 challenging images from human and pig coronaries, and rabbit iliac arteries; the outcomes were compared with the gold standards made by experts. The resultant accuracy was obtained: True Positive (%) = 99.29 ± 2.96, False Positive (%) = 3.69 ± 2.88, False Negative (%) = 0.71 ± 2.96, Max False Positive Distance (mm) = 0.1 ± 0.07, Max False Negative Distance (mm) = 0.06 ± 0.1. Conclusions In conclusion, by segmenting a number of IVOCT images with various features, the proposed technique showed to be robust and more accurate than published studies; in addition, the method is completely automatic, providing a new tool for IVOCT segmentation.

Morphological characterization of the nasopalatine region in human fetuses and its association to pathologies

The nasopalatine region is composed of structures such as the vomeronasal organ and nasopalatine duct. The nasopalatine duct may provide the communication of the mouth to the nasal cavity in human fetuses and can be obliterated in an adult human. Knowledge on the development of the nasopalatine region and nasopalatine duct in humans is necessary for understanding the morphology and etiopathogenesis of lesions that occur in this region. Objective: The aim of the present study was to describe the morphological aspects of the nasopalatine region in human fetuses and correlate these aspects with the development of pathologies in this region. Material and Methods: Five human fetuses with no facial or palatine abnormalities were used for the acquisition of specimens from the nasopalatine region. After demineralization, the specimens were histologically processed. Histological cuts were stained with methylene blue to orient the cutting plane and hematoxylin-eosin for the descriptive histological analysis. Results: The age of the fetuses was 8.00, 8.25, 9.00 and 9.25 weeks, and it was not possible to determine the age in the last one. The incisive canal was observed in all specimens as an opening delimited laterally by the periosteum and connecting oral and nasal cavity. The nasopalatine duct is an epithelial structure with the greatest morphological variation, with either unilateral or bilateral occurrence and total patent, partial patent and islet forms. The vomeronasal organ is a bilateral epithelized structure located alongside the nasal septum above the incisive canal in all the fetuses. Conclusions: The incisive canal, nasopalatine duct and vomeronasal organ are distinct anatomic structures. The development of nasopalatine duct cysts may occur in all forms of the nasopalatine duct.

Morphometric analysis of the placenta in the New World mouse Necromys lasiurus (Rodentia, Cricetidae): a comparison of placental development in cricetids and murids

Background: Stereology is an established method to extrapolate three-dimensional quantities from two-dimensional images. It was applied to placentation in the mouse, but not yet for other rodents. Herein, we provide the first study on quantitative placental development in a sigmodontine rodent species with relatively similar gestational time. Placental structure was also compared to the mouse, in order to evaluate similarities and differences in developmental patterns at the end of gestation. Methods: Fetal and placental tissues of Necromys lasiurus were collected and weighed at 3 different stages of gestation (early, mid and late gestation) for placental stereology. The total and relative volumes of placenta and of its main layers were investigated. Volume fractions of labyrinth components were quantified by the One Stop method in 31 placentae collected from different individuals, using the Mercator® software. Data generated at the end of gestation from N. lasiurus placentae were compared to those of Mus musculus domesticus obtained at the same stage. Results: A significant increase in the total absolute volumes of the placenta and its main layers occurred from early to mid-gestation, followed by a reduction near term, with the labyrinth layer becoming the most prominent area. Moreover, at the end of gestation, the total volume of the mouse placenta was significantly increased compared to that of N. lasiurus although the proportions of the labyrinth layer and junctional zones were similar. Analysis of the volume fractions of the components in the labyrinth indicated a significant increase in fetal vessels and sinusoidal giant cells, a decrease in labyrinthine trophoblast whereas the proportion of maternal blood space remained stable in the course of gestation. On the other hand, in the mouse, volume fractions of fetal vessels and sinusoidal giant cells decreased whereas the volume fraction of labyrinthine trophoblast increased compared to N. lasiurus placenta. Conclusions: Placental development differed between N. lasiurus and M. musculus domesticus. In particular, the low placental efficiency in N. lasiurus seemed to induce morphological optimization of fetomaternal exchanges. In conclusion, despite similar structural aspects of placentation in these species, the quantitative dynamics showed important differences.

Morphological and molecular studies on the Brazilian native red seaweed Laurencia oliveirana (Rhodomelaceae, Ceramiales)

Morphological and molecular studies were carried out on Laurencia oliveirana from the type locality (Arraial do Cabo, Rio de Janeiro, Brazil). This species is easily recognized by its small size, sub-erect habit forming intricate cushion-like tufts and unilateral pectinate branching. The species displays all the typical characters of the genus Laurencia, such as the production of the first pericentral cell underneath the basal cell of the trichoblast, tetrasporangia produced from particular pericentral cells, with the third and fourth pericentral cells becoming fertile, without production of additional pericentral cells, spermatangial branches produced from one of two laterals on the suprabasal cell of trichoblasts, and procarp-bearing segment with five pericentral cells. Details of tetrasporangial plants and development of procarp and male plants are described for the first time for the species. The phylogenetic position of L. oliveirana was inferred by analysis of the chloroplast-encoded rbcL gene sequences from 57 taxa. In all phylogenetic analyses, L. oliveirana grouped with L. caraibica, L. caduciramulosa, L. venusta and L. natalensis, forming a monophyletic clade within the Laurencia sensu stricto. The genetic divergence between L. oliveirana and the molecularly closest species, L. caraiba collected in Brazil, was 2.3%.

Embryonic development and larval stages of Steindachneridion parahybae (Siluriformes: Pimelodidae): implications for the conservation and rearing of this endangered Neotropical species

Steindachneridion parahybae is a freshwater catfish endemic to the Paraíba do Sul River and is classified as an endangered Neotropical species. An increasing number of conservation biologists are incorporating morphological and physiological research data to help conservation managers in rescue these endangered species. This study investigated the embryonic and larval development of S. parahybae in captivity, with emphasis in major events during the ontogeny of S. parahybae. Broodstocks were artificially induced to reproduce, and the extrusion occurred 200-255 degree-hours after hormonal induction at 24°C. Larval ontogeny was evaluated every 10 minutes under microscopic/stereomicroscopic using fresh eggs samples. The main embryogenic development stages were identified: zygote, cleavage, including the morula, blastula, gastrula phase, organogenesis, and hatching. The extruded oocytes showed an average diameter of 1.10 ± 0.10 mm, and after fertilization and hydration of eggs, the average diameter of eggs increased to about 1.90 ± 0.60 mm, characterized by a large perivitelline space that persisted up to embryo development, the double chorion, and the poles (animal and vegetative). Cell division started about 2 minutes after fertilization (AF), resulting in 2, 4, 8 (4 x 2 arrangement of cells), 16 (4 x 4), 32 (4 x 8) and 64 (2 x 4 x 8) cells. Furthermore, the blastula and gastrula stages followed after these cells divisions. The closed blastopore occurred at 11 h 20 min AF; following the development, the organogenetic stages were identified and subdivided respectively in: early segmentation phase and late segmentation phase. In the early segmentation phase, there was the establishment of the embryonic axis, and it was possible to distinguish between the cephalic and caudal regions; somites, and the optic vesicles developed about 20 h AF. Total hatching occurred at 54 h AF, and the larvae average length was 4.30 ± 0.70 mm. Gradual yolk sac reduction was observed during the first two days of larval development. The first feeding occurred at the end of the second day. During the larval phase, cannibalism, heterogeneous larval growth and photophobia were also observed. This information will be important in improving the artificial reproduction protocols of S. parahybae in controlled breeding programs.

On the morphological differentiation between Libinia spinosa and L. ferreirae (Crustacea: Brachyura: Majoidea: Epialtidae)

Libinia spinosa H. Milne Edwards in Guérin, 1832 and L. ferreirae Brito Capello, 1871, inhabit very similar environments, and their geographic and bathymetric distributions overlap for about 3000 km along the southwestern Atlantic. Both species are commonly caught in the same haul and differentiating between them can often be difficult. Traditionally, morphological differentiation between L. spinosa and L. ferreirae has been based exclusively on the number of spines along the median, longitudinal line of the carapace and the development of a process at the anterolateral angle of the basal segment of the antenna. Because Libinia spinosa and L. ferreirae share similar numbers of median spines (7 and 6, respectively), and the number of median spines of the carapace and the process at the anterolateral angle of the basal antennal segment are variable, they are of little value in separating these species. It is shown herein that unequivocal identification can be easily achieved based on features of the male and female thoracic sternum, pereiopod dactyli, and infraorbital notch. A lectotype is designated for L. spinosa and its authorship and date are corrected. Libinia gibbosa A. Milne-Edwards, 1878, is demonstrated to be a junior synonym of L. ferreirae. The holotype of L. gibbosa is figured for the first time.

Submandibular glands and the regulation of gastric proliferation and TGFα distribution during rat postnatal development

Rodent gastric mucosa grows and differentiates during suckling-weaning transition. Among the molecules in rat milk, EGF and TGFβ are important peptides in the control of cell proliferation, and together with TGFα, they are also produced by submandibular glands. We aimed to determine the effect of saliva and milk on epithelial cell proliferation in the stomach of rat pups. We also examined the distribution of TGFα in the gastric mucosa after sialoadenectomy (SIALO) and fasting in order to determine whether this growth factor is affected by the deprivation of molecules derived from saliva and milk. SIALO was performed at 14 days and fasting was induced 3 days later. Cell proliferation was evaluated through metaphasic index and TGFα was detected by immunohistochemistry. We observed that whereas SIALO did not alter cell division, since the metaphasic index (MI) was unchanged, fasting stimulated cell proliferation (P < 0.05). After SIALO and fasting, MI was reduced when compared to the fasted group (P < 0.05). We found that TGFα is distributed along gastric gland and SIALO did not interfere in the localization and number of immunolabeled cells, but fasting increased their density when compared to the control (P < 0.05). The association of SIALO and fasting reduced TGFα immunostaining (P < 0.05). Therefore, during fasting, high MI was parallel to increased TGFα in gastric epithelium, but interestingly, this effect was found only in the presence of submandibular glands. We suggest that during suckling, peptides derived from saliva and milk are important to regulate gastric growth.