Reproductive cycle and gonad development of the Northern Argentinean Mesodesma mactroides (Bivalvia: Mesodesmatidae)

The reproductive cycle and gonad development of the yellow clam Mesodesma mactroides was studied over a period of 24 months (January 2005?December 2006) at the Argentinean sandy beach Santa Teresita. Histological examination of gonadal tissue revealed that sex ratios did notsignificantly deviate from the proportion of 1:1 and no case of hermaphroditism was found. The reproductive cycle of M. mactroides followed an annual cyclicality, which was significantly correlated to monthly mean sea surface temperatures (SST). Oocytes showed highest abundance in winter, indicating a process of gonadal development and sexual maturation. The mean oocyte size decreased significantly during spring. Modal oocyte sizes decreased significantly during winter and late spring of each year, suggesting spawning events. The condition index was not useful in describing the annual reproductive cycle of M. mactroides. Ash-free, shell-free dry mass was chosen to detect the condition of the specimens, and this significantly correlated with monthly mean SST and the gametogenic cycle. Annual recruitment patterns during summer?autumn indicated a 3-month-long planktonic phase of M. mactroides. The reproduction cycle and gonad development of M. mactroides showed only weak differences between data from the present study and those collected 40 years ago.Fil: Herrmann, Marko. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Alfred Wegener Institute for Polar and Marine Research; AlemaniaFil: Fernandez Alfaya, Jose Elias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lepore, Mauro L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Laudien, Jurgen. Alfred Wegener Institute for Polar and Marine Research; Alemani

Application of calcein for estimating growth of the yellow clam Mesodesma mactroides Reeve, 1854

La tasa de crecimiento de un organismo provee información ecológica básica e importante para el estudio de su dinámica poblacional. En los bivalvos, dado que muchas especies son importantes en la industria pesquera, este parámetro se ha estudiado detalladamente mediante numerosos métodos, entre ellos, análisis de distribuciones de frecuencia de tallas, análisis de anillos de crecimiento de la concha y análisis de incrementos de talla siguiendo experimentos de marcaje-recaptura. Las estimaciones de crecimiento y longevidad resultantes de métodos diferentes son a veces contradictorias, por ejemplo Capezzani et al. (1971) reportaron una longevidad de ~ 8 años para Mesodesma mactroides Reeve, 1854, mientras que Defeo et al. (1988) sugirieron ~ 3,5 años para la misma especie. Los métodos actuales para la determinación del crecimiento y la edad de los bivalvos tienen sus limitaciones específicas. Los análisis de distribuciones de frecuencia de tallas (DFT) requieren cohortes de edad bien definida y, normalmente, gran tamaño muestral. La cuantificación de anillos de crecimiento de la concha es afectada por la erosión superficial y los eventos disruptivos (para revisiones de métodos de crecimiento ver Richardson 2001), mientras que los métodos de marcaje-recaptura invasivos promueven disturbios físicos y, eventualmente, tasas de crecimiento no-características. Diferentes estudios han probado varios químicos como marcadores del crecimiento de la concha en diferentes invertebrados marinos (Nakahara 1961, Monaghan 1993, Pricker & Schie 1993, Day et al. 1995, Peck et al. 1996); dentro de la diversidad de marcadores, se ha demostrado que la calceína es apropiada para investigar los incrementos de crecimiento en bivalvos después del marcaje (Kaehler & McQuaid 1999, Fujikura et al. 2003, Heilmayer et al. 2005, Riascos et al. 2006, Riascos et al. 2008, Herrmann et al. 2009). La calceína polianiónica es un compuesto fluorescente que se une con el carbonato de calcio en estructuras en crecimiento biomineralizadas (como las conchas) de organismos y que emite un color verde lima fluorescente cuando se ve bajo luz azul (Wilson et al. 1987). El objetivo del presente trabajo fue determinar la tasa de crecimiento diario in situ de la almeja amarilla Mesodesma mactroides Reeve, 18541 (Bivalvia: Mesodesmatidae) sobre la base a un experimento de marcaje fluorescente in situ (MFI). Además, estimar los parámetros de la ecuación de crecimiento de von Bertalanffy (ECVB) para comparar los resultados con los parámetros de crecimiento estimados a partir de DFT, comparando los residuos y aplicando un índice de eficiencia del crecimiento (EC, traducido del término en inglés `overall growth performance' OGP).Growth rates of Mesodesma mactroides were estimated comparing two different methods at the intertidal of the exposed sandy beach Santa Teresita, Argentina. Results of a short tagging-recapture experiment using the in situ fluorescent marking (MFI) method and subsequent size-increment analysis were compared with results from length-frequency distributions (DFT) analysis from a 25 month quantitative sampling. Residuals, derived from MFI method and DFT analysis, were of similar magnitude and distribution, suggesting that both methods are equally appropriate to estimate growth of M. mactroides. Calcein was useful as non-lethal growth marker for M. mactroides, emitting a bright green fluorescence band under blue light.Fil: Lepore, Mauro L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Penchaszadeh, Pablo Enrique. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Fernandez Alfaya, Jose Elias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Herrmann, Marko. Alfred Wegener Institute for Polar and Marine Research; Alemani

Overexpression of a mutant form of TGFBI/BIGH3 induces retinal degeneration in transgenic mice

PURPOSE: Despite ubiquitous expression of the keratoepithelin (KE) protein encoded by the transforming growth factor beta induced/beta induced gene human clone 3 (TGFBI/BIGH3) gene, corneal dystrophies are restricted to the cornea, and no other tissues are affected. We investigated the role of TGFBI/BIGH3 in Groenouw corneal dystrophies by generating transgenic mice overexpressing TGFBI/BIGH3 containing the R555W mutation. METHODS: Transgenic animals expressing the Groenouw mutation of human TGFBI/BIGH3 were generated using lentiviral vectors. The line expressed TGFBI/BIGH3 containing the R555W mutation under the control of the phosphoglycerate kinase (PGK) promoter. Expression of the transgene was monitored by Southern and western blotting and by RT-PCR. Electroretinogram analysis was performed and four mice were subjected to complete necroscopy. RESULTS: Transgene expression was observed in different organs although without specific expression in the cornea. The overall morphology of the transgenic animals was not severely affected by KE overexpression. However, we observed an age-dependent retinal degeneration both functionally and histologically. Female-specific follicular hyperplasia in the spleen and increased levels of lipofuscin in the adrenal gland were also seen in transgenic animals. CONCLUSIONS: Cellular degeneration in the retina of transgenic animals suggest that perturbation of the transforming growth factor beta (TGFbeta) family regulation may affect photoreceptor survival and may induce possible accelerated aging in several tissues. No corneal phenotype could be observed, probably due to the lack of transgene expression in this tissue

allodb: An R package for biomass estimation at globally distributed extratropical forest plots

Allometric equations for calculation of tree above-ground biomass (AGB) form the basis for estimates of forest carbon storage and exchange with the atmosphere. While standard models exist to calculate forest biomass across the tropics, we lack a standardized tool for computing AGB across boreal and temperate regions that comprise the global extratropics. Here we present an integrated R package, allodb, containing systematically selected published allometric equations and proposed functions to compute AGB. The data component of the package is based on 701 woody species identified at 24 large Forest Global Earth Observatory (ForestGEO) forest dynamics plots representing a wide diversity of extratropical forests. A total of 570 parsed allometric equations to estimate individual tree biomass were retrieved, checked and combined using a weighting function designed to ensure optimal equation selection over the full tree size range with smooth transitions across equations. The equation dataset can be customized with built-in functions that subset the original dataset and add new equations. Although equations were curated based on a limited set of forest communities and number of species, this resource is appropriate for large portions of the global extratropics and can easily be expanded to cover novel forest types

An HLA-E-targeted TCR bispecific molecule redirects T cell immunity against Mycobacterium tuberculosis

Peptides presented by HLA - E, a molecule with very limited polymorphism, represent attractive targets for T cell receptor (TCR) - based immunotherapies to circumvent the limitations imposed by the high polymorphism of classical HLA genes in the human population. Here, we describe a TCR - based bispecific molecule that potently and selectively binds HLA - E in complex with a peptide encoded by the inhA gene of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis in humans. We reveal the biophysical and structural bases underpinning the potency and specificity of this molecule and demonstrate its ability to redirect polyclonal T cells to target HLA - E - expressing cells transduced with mycobacterial inhA as well as primary cells infected with virulent Mtb. Additionally, we demonstrate elimination of Mtb - infected cells and reduction of intracellular Mtb growth. Our study suggests an approach to enhance host T cell immunity against Mtb and provides proof of principle for an innovative TCR - based therapeutic strategy overcoming HLA polymorphism and therefore applicable to a broader patient population

MAIT cells launch a rapid, robust and distinct hyperinflammatory response to bacterial superantigens and quickly acquire an anergic phenotype that impedes their cognate antimicrobial function: Defining a novel mechanism of superantigen-induced immunopathology and immunosuppression

Superantigens (SAgs) are potent exotoxins secreted by Staphylococcus aureus and Streptococcus pyogenes. They target a large fraction of T cell pools to set in motion a "cytokine storm" with severe and sometimes life-threatening consequences typically encountered in toxic shock syndrome (TSS). Given the rapidity with which TSS develops, designing timely and truly targeted therapies for this syndrome requires identification of key mediators of the cytokine storm's initial wave. Equally important, early host responses to SAgs can be accompanied or followed by a state of immunosuppression, which in turn jeopardizes the host's ability to combat and clear infections. Unlike in mouse models, the mechanisms underlying SAg-associated immunosuppression in humans are ill-defined. In this work, we have identified a population of innate-like T cells, called mucosa-associated invariant T (MAIT) cells, as the most powerful source of pro-inflammatory cytokines after exposure to SAgs. We have utilized primary human peripheral blood and hepatic mononuclear cells, mouse MAIT hybridoma lines, HLA-DR4-transgenic mice, MAIThighHLA-DR4+ bone marrow chimeras, and humanized NOD-scid IL-2Rγnull mice to demonstrate for the first time that: i) mouse and human MAIT cells are hyperresponsive to SAgs, typified by staphylococcal enterotoxin B (SEB); ii) the human MAIT cell response to SEB is rapid and far greater in magnitude than that launched by unfractionated conventional T, invariant natural killer T (iNKT) or γδ T cells, and is characterized by production of interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-2, but not IL-17A; iii) high-affinity MHC class II interaction with SAgs, but not MHC-related protein 1 (MR1) participation, is required for MAIT cell activation; iv) MAIT cell responses to SEB can occur in a T cell receptor (TCR) Vβ-specific manner but are largely contributed by IL-12 and IL-18; v) as MAIT cells are primed by SAgs, they also begin to develop a molecular signature consistent with exhaustion and failure to participate in antimicrobial defense. Accordingly, they upregulate lymphocyte-activation gene 3 (LAG-3), T cell immunoglobulin and mucin-3 (TIM-3), and/or programmed cell death-1 (PD-1), and acquire an anergic phenotype that interferes with their cognate function against Klebsiella pneumoniae and Escherichia coli; vi) MAIT cell hyperactivation and anergy co-utilize a signaling pathway that is governed by p38 and MEK1/2. Collectively, our findings demonstrate a pathogenic, rather than protective, role for MAIT cells during infection. Furthermore, we propose a novel mechanism of SAg-associated immunosuppression in humans. MAIT cells may therefore provide an attractive therapeutic target for the management of both early and late phases of severe SAg-mediated illnesses

Overexpression of a mutant form of TGFBI/BIGH3 induces retinal degeneration in transgenic mice

Purpose: Despite ubiquitous expression of the keratoepithelin (KE) protein encoded by the transforming growth factor beta induced/beta induced gene human clone 3 (TGFBI/BIGH3) gene, corneal dystrophies are restricted to the cornea, and no other tissues are affected. We investigated the role of TGFBI/BIGH3 in Groenouw corneal dystrophies by generating transgenic mice overexpressing TGFBI/BIGH3 containing the R555W mutation

Growth study of the Argentinean wedge clam Donax hanleyanus: A comparative analysis between length-frequency distribution and in situ fluorescent marking method

Growth rates of the Argentinean wedge clam Donax hanleyanus were estimated comparing two different methods in the intertidal of the exposed sandy beach Mar de las Pampas: (i) results of a relatively shortly (49 days) tagging-recapture experiment using the in situ fluorescent marking (IFM) method and subsequent size-increment analyses were compared with results from (ii) length-frequency distributions (LFD) analysis originating from a time consuming 25 month quantitative sampling. Residuals, derived from IFM method and LFD analysis, were of similar magnitude and distribution, indicating that both methods are equally appropriate to estimate growth of D. hanleyanus. Comparing overall growth performance indices (OGPs) of several Donax species from different climate areas it resulted that growth of temperate bivalves can be estimated well by carrying out a relatively short-time tagging-recapture experiment using IFM but it is recommended to use both, the IFM as well as the LFD method to determine growth of tropical bivalves. Furthermore, an in vitro suitability test of the three stains strontium chloride hexahydrate, alizarin red and calcein resulted that the latter is useful as non-lethal growth marker for D. hanleyanus, emitting a bright green fluorescence band under blue light

A U-Th dating approach to understanding past coral reef dynamics and geomorphological constraints on future reef growth potential; Mazie Bay, Southern Great Barrier Reef

Reconstructing coral reef histories provides a window of understanding into reef response to changing environmental and climatic conditions over various temporal scales. Here we present the results of 117 U-Th dates from emergent reef flat and slope cores and surface death assemblages, combined with previously published fossil microatoll data, to capture the entire sequence of reef growth at Mazie Bay, inshore Southern Great Barrier Reef (GBR). Coral U-Th dates indicate that Mazie Bay reef initiated ~6,900 years before present (yr. BP) quickly filling accommodation space. While rates of vertical reef accretion (5.3 ± 1.0 mm year) were comparable to the GBR average during the mid-Holocene (~5.0 mm year), reef flat progradation occurred at a rate 1.5- to 6-fold previous GBR rates until 5,100 yr. BP (~70.4 cm year). Average progradation slowed to ~7.1 cm year in the subsequent ~4,000 years and reef slope cores indicate this reef had largely “turned-off” by 400 yr. BP, with modern coral communities existing as a veneer over the largely senescent framework. Death assemblage dates highlight coral disturbance and recovery regimes in response to increased cyclone activity 1960–1985 AD and recent extreme sea surface temperature and flood events post 2000 AD. U-Th dating of mid-Holocene to modern coral deposits from Mazie Bay reef provides a unique insight into past reef development, response to recent disturbance regimes, and potential for future reef growth. In the case of Mazie Bay, our data suggest limited accommodation space and increased occurrence of sea surface temperature extremes will restrict future reef growth at this site