NUCLEATION PROCESSES IN HIGH-RELIEF CARBONATE PLATFORMS: SEDIMENTOLOGIC CHARACTERIZATION, FACIES COMPOSITION AND DEPOSITIONAL EVOLUTION OF THE ESINO LIMESTONE (LADINIAN-LOWER CARNIAN) IN LOMBARDY

High-relief carbonate platforms evolve from a poorly known nucleation stage that has different environmental conditions and depositional processes with respect to the mature stage of the platform. To understand the processes that lead to the development of a high-relief carbonate platform, it is crucial to analyze facies type and distribution during the early phase of their development. The Esino Limestone (up to 800m thick, with a final platform-to-basin relief of 550 m) preserves exposed the inception stage deposits. In its mature configuration the carbonate system was characterized by a wide inner platform (bedded peritidal limestones with stromatolites, oncoids, fenestrae and dasycladaceans), bordered by a narrow reef (Tubiphytes and microbial mounds associated with coral framestones with calcisponges and intrabioclastic packstone) that sourced the breccias of the steep slopes. 20 stratigraphic sections have been measured and about 600 samples for microfacies analysis have been collected in the 30-130 meters-thick succession of the nucleation stage. Facies type and distribution led to the stratigraphic reconstruction and to the identification of major phases in the early platform evolution, which are linked with relative sea-level changes. A first transgression, following the drowning of the antecedent peritidal platform (Camorelli Limestone), is characterized by the deposition of dark bioturbated bio-intraclastic packstone and wackestone passing to bedded black marly limestones and marls (Prezzo Limestone). A general regressive trend is characterized by intraclastic packstones and decreased terrigenous input. Sparse reefal bafflestones (porifera, algae, corals, Tubiphytes) and peritidal facies (stromatolitic bindstone with fenestrae, early marine cements, intrabioclastic packstone) record the final onset of the core of the future high relief carbonate platform. The end of the inception stage is thus controlled by the progradation of sparse patch reefs that fill up the depositional space, leading to the coalescence of isolated small nuclei of carbonate production. This study documented the key role played by antecedent topography and sea-level changes in the localization and growth of the first platform nuclei. Furthermore, environmental conditions (e.g. terrigenous input, water circulation) possibly exerted a control on the organisms\u2019 associations that characterized the first stages of platform evolution

Cancer-associated epithelial cell adhesion molecule (EpCAM; CD326) enables epidermal Langerhans cell motility and migration in vivo

After activation, Langerhans cells (LC), a distinct subpopulation of epidermis-resident dendritic cells, migrate from skin to lymph nodes where they regulate the magnitude and quality of immune responses initiated by epicutaneously applied antigens. Modulation of LC-keratinocyte adhesion is likely to be central to regulation of LC migration. LC express high levels of epithelial cell adhesion molecule (EpCAM; CD326), a cell-surface protein that is characteristic of some epithelia and many carcinomas and that has been implicated in intercellular adhesion and metastasis. To gain insight into EpCAM function in a physiologic context in vivo, we generated conditional knockout mice with EpCAM-deficient LC and characterized them. Epidermis from these mice contained increased numbers of LC with normal levels of MHC and costimulatory molecules and T-cell-stimulatory activity in vitro. Migration of EpCAM-deficient LC from skin explants was inhibited, but chemotaxis of dissociated LC was not. Correspondingly, the ability of contact allergen-stimulated, EpCAM-deficient LC to exit epidermis in vivo was delayed, and strikingly fewer hapten-bearing LC subsequently accumulated in lymph nodes. Attenuated migration of EpCAM-deficient LC resulted in enhanced contact hypersensitivity responses as previously described in LC-deficient mice. Intravital microscopy revealed reduced translocation and dendrite motility in EpCAM-deficient LC in vivo in contact allergen-treated mice. These results conclusively link EpCAM expression to LC motility/migration and LC migration to immune regulation. EpCAM appears to promote LC migration from epidermis by decreasing LC-keratinocyte adhesion and may modulate intercellular adhesion and cell movement within in epithelia during development and carcinogenesis in an analogous fashion

Testis Developmental Phenotypes in Neurotropin Receptor trkA and trkC Null Mutations: Role in Formation of Seminiferous Cords and Germ Cell Survival

The objective of the present study was to determine if the neurotropin receptors trkC and trkA are involved in embryonic testis development. These receptors bind neurotropin 3 and nerve growth factor, respectively. The hypothesis tested was that the absence of trkC or trkA receptors will have detrimental effects on testis development and morphology. The trkA and trkC homozygote knockout (KO) mice generally die either at or shortly after birth. Therefore, heterozygote mice were mated to obtain homozygote gene KO mice at Embryonic Day (E) 13, E14, E17, and E19 of gestation, with E0 being the plug date. Gonads from approximately 80 embryos were collected and fixed, and each embryo was genotyped. To determine gonadal characteristics for each genotype, the number of germ cells, number of seminiferous cords, seminiferous cord area, and interstitial area were calculated at each developmental age. Germ cell numbers varied in trkA gene KO mice from those of wild-type mice at each age evaluated. In trkC gene KO mice, differences were detected in germ cell numbers when compared to wild-type mice at E17 and E19. At E19, germ cell numbers were reduced in both trkA and trkC gene KO mice when compared to wild-type animals. Apoptosis was evaluated in testes of wild-type, trkC gene KO, and trkA gene KO mice to determine if the alteration in germ cell numbers at each developmental age was influenced by different patterns of germ cell survival or apoptosis. No differences were found in germ cell apoptosis during embryonic testis development. Interestingly, trkA gene KO mice that survived to Postnatal Day 19 had a 10-fold increase in germ cell apoptosis when compared to germ cells in wild-type mice. Evaluation of other morphological testis parameters demonstrated that trkC KO testes had reduced interstitial area at E13, reduced number of seminiferous cords at E14, and reduced seminiferous cord area at E19. The trkA gene KO testes had a reduction in the number of seminiferous cords at E14. Histology of both trkA and trkC gene KO testes demonstrated that these gonads appear to be developmentally delayed when compared to their wild-type testis counterparts at E13 during testis development. The current study demonstrates that both trkA and trkC neurotropin receptors influence germ cell numbers during testis development and events such as seminiferous cord formation

Transition between terrestrial-submerged walking and swimming revealed by Early Permian amphibian trackways and a new proposal for the nomenclature of compound trace fossils

Exceptionally preserved Early Permian tetrapod trackways from the Orobic Basin (Central-Western Southern Alps) offer a unique opportunity to investigate in detail locomotion in fossil vertebrates that lived on continental European landmasses. Herein are reported the results of a study on several tetrapod trackways that display a large variety of behavioral, gait and substrate related extramorphologies. They clearly document the transition from terrestrial-underwater walking to swimming and are assigned to the compound ichnotaxon Batrachichnus C Lunichnium. The use of the "C" symbol is here introduced for the first time as nomenclatural indication of a Compound trace. Producers were probably small-sized temnospondyl or lepospondyl (microsaurs) amphibians. Comparisons with living urodelan anatomy and mechanics provide evidence for conservatism of locomotor mechanics in evolutionary history among amphibians. The derived model for locomotor kinematics in Early Permian amphibians provides a reference for interpreting transitional land-to-water trackways. The shift from walking to swimming behavior in early tetrapods, as in extant urodelan amphibians, is described as a complex balance between different dynamics

DAAM1 and DAAM2 are co-required for myocardial maturation and sarcomere assembly

AbstractWnt ligands regulate heart morphogenesis but the underlying mechanisms remain unclear. Two Formin-related proteins, DAAM1 and 2, were previously found to bind the Wnt effector Disheveled. Here, since DAAM1 and 2 nucleate actin and mediate Wnt-induced cytoskeletal changes, a floxed-allele of Daam1 was used to disrupt its function specifically in the myocardium and investigate Wnt-associated pathways. Homozygous Daam1 conditional knockout (CKO) mice were viable but had misshapen hearts and poor cardiac function. The defects in Daam1 CKO mice were observed by mid-gestation and were associated with a loss of protrusions from cardiomyocytes invading the outflow tract. Further, these mice exhibited noncompaction cardiomyopathy (NCM) and deranged cardiomyocyte polarity. Interestingly, Daam1 CKO mice that were also homozygous for an insertion disrupting Daam2 (DKO) had stronger NCM, severely reduced cardiac function, disrupted sarcomere structure, and increased myocardial proliferation, suggesting that DAAM1 and DAAM2 have redundant functions. While RhoA was unaffected in the hearts of Daam1/2 DKO mice, AKT activity was lower than in controls, raising the issue of whether DAAM1/2 are only mediating Wnt signaling. Daam1-floxed mice were thus bred to Wnt5a null mice to identify genetic interactions. The hearts of Daam1 CKO mice that were also heterozygous for the null allele of Wnt5a had stronger NCM and more severe loss of cardiac function than Daam1 CKO mice, consistent with DAAM1 and Wnt5a acting in a common pathway. However, deleting Daam1 further disrupted Wnt5a homozygous-null hearts, suggesting that DAAM1 also has Wnt5a-independent roles in cardiac development

The Cytoskeletal Adaptor Protein Band 4.1B Is Required for the Maintenance of Paranodal Axoglial Septate Junctions in Myelinated Axons

Precise targeting and maintenance of axonal domains in myelinated axons is essential for saltatory conduction. Caspr and Caspr2, which localize at paranodal and juxtaparanodal domains, contain binding sites for the cytoskeletal adaptor protein 4.1B. The exact role of 4.1B in the organization and maintenance of axonal domains is still not clear. Here we report the generation and characterization of 4.1B null mice. We show that loss of 4.1B in the PNS results in mislocalization of Caspr at paranodes and destabilization of paranodal axo-glial septate junctions (AGSJs) as early as postnatal day 30. In the CNS, Caspr localization is progressively disrupted and ultrastructural analysis showed paranodal regions that were completely devoid of AGSJs, with axolemma separated from the myelin loops, and loops coming off the axolemma. Most importantly, our phenotypic analysis of previously generated 4.1B mutants, used in Horresh et al. (2010), showed that Caspr localization was not affected in the PNS, even after one year; and 4.1R was neither expressed, nor enriched at the paranodes. Furthermore, ultrastructural analysis of these 4.1B mutants showed destabilization of CNS AGSJs at about one year. We also discovered that the 4.1B locus is differentially expressed in the PNS and CNS, and generates multiple splice isoforms in the PNS, suggesting 4.1B may function differently in the PNS versus CNS. Together, our studies provide direct evidence that 4.1B plays a pivotal role in interactions between the paranodal AGSJs and axonal cytoskeleton, and that 4.1B is critically required for long-term maintenance of axonal domains in myelinated axons

Soja resistente à ferrugem: participação de compostos voláteis nas respostas de defesa?

A ferrugem asiática da soja (FAS), causada por Phakopsora pachyrhizi, é uma grande ameaça à sojicultura brasileira. A avaliação das atividades de enzimas marcadoras de indução de resistência pode auxiliar na elucidação de mecanismos envolvidos em respostas de defesa das plantas. Proteína total e atividades de enzimas marcadoras da indução de resistência foram determinadas em extratos de folhas de plantas dos genótipos PI561356 (resistente, PI) e Embrapa 48 (susceptível, E48), inoculadas ou não com P. pachyrhizi. Respostas muito discrepantes entre os dois genótipos e entre os tempos de coleta (12, 72 e 168 h após inoculação) foram observadas, em especial para lipoxigenases e B-1, 3-glucanases. Diferentemente de E48, plantas de PI responderam tardiamente à inoculação pelo fungo com a redução da concentração da proteína total e de atividades enzimáticas. Os dados indicam que as vias que envolvem ação dessas duas enzimas devem participar ativamente da defesa das plantas de soja de E48, mas não de PI. Uma hipótese para explicar a resistência de PI é que voláteis produzidos por plantas inoculadas atuam como moduladores da resposta de defesa