Wolbachia Utilize Host Actin for Efficient Maternal Transmission in Drosophila melanogaster

Wolbachia pipientis is a ubiquitous, maternally transmitted bacterium that infects the germline of insect hosts. Estimates are that Wolbachia infect nearly 40% of insect species on the planet, making it the most prevalent infection on Earth. The bacterium, infamous for the reproductive phenotypes it induces in arthropod hosts, has risen to recent prominence due to its use in vector control. Wolbachia infection prevents the colonization of vectors by RNA viruses, including Drosophila C virus and important human pathogens such as Dengue and Chikungunya. Here we present data indicating that Wolbachia utilize the host actin cytoskeleton during oogenesis for persistence within and transmission between Drosophila melanogaster generations. We show that phenotypically wild type flies heterozygous for cytoskeletal mutations in Drosophila profilin (chic²²¹/+ and chic¹³²⁰/+) or villin (qua^6-396/+) either clear a Wolbachia infection, or result in significantly reduced infection levels. This reduction of Wolbachia is supported by PCR evidence, Western blot results and cytological examination. This phenotype is unlikely to be the result of maternal loading defects, defects in oocyte polarization, or germline stem cell proliferation, as the flies are phenotypically wild type in egg size, shape, and number. Importantly, however, heterozygous mutant flies exhibit decreased total G-actin in the ovary, compared to control flies and chic²²¹ heterozygous mutants exhibit decreased expression of profilin. Additionally, RNAi knockdown of profilin during development decreases Wolbachia titers. We analyze evidence in support of alternative theories to explain this Wolbachia phenotype and conclude that our results support the hypothesis that Wolbachia utilize the actin skeleton for efficient transmission and maintenance within Drosophila.     

Semiotics of Communication: From Semiosis of Nature to Culture

Communication Studies currently undergoes a crisis of paradigms that requires an ontological review that must begin with a debate about the conditions of possibility of every communicational phenomena. In this article we argue that semiosis offers a conceptual framework that allows for the study of communication as qualitative action. Semiosis, or the action of the sign, is here defined as a fundamental process based on perception that models the world of species, creating cognition and culture. At the core of semiosis are dynamic structures that the authors have defined as ‘ontological diagrams’. The first purpose of Semiotics of Communication is to understand how these modeling systems evolve ontologically and phylogenically, producing, in the case of human culture, means of communication ever more varied and technologically advanced.     

Winter survival of North American grassland birds is driven by weather and grassland condition in the Chihuahuan Desert

Populations of grassland birds that overwinter in the Chihuahuan Desert are declining more rapidly than other grassland birds, and survival during the non‐breeding season may have a strong influence on population trends of these species. Habitat loss and deterioration due to desertification may be contributing to these declines, and the winter ecology of grassland birds under these changing environmental conditions remains relatively unexplored. To fill this information gap, we estimated the survival of two grassland‐obligate sparrows, Baird's Sparrows (Ammodramus bairdii) and Grasshopper Sparrows (A. savannarum), on their wintering grounds in the Chihuahuan Desert, and investigated the role of habitat structure and weather on survival rates. We deployed radio‐transmitters on Baird's (N = 49) and Grasshopper (N = 126) sparrows near Janos, Chihuahua, and tracked birds from November to March during the winters of 2012–2013 and 2013–2014. Causes of mortality included avian predators, mammals, and possibly weather. We estimated an overall weekly winter survival probability of ? = 92.73% (95% CI[s] = 88.63–95.44%) for Baird's Sparrows in 2012–2013. We estimated a weekly winter survival probability of ? = 93.48% (95% CI[s] = 90.29–96.67%) and ? = 98.78% (95% CI[s] = 97.88–99.68%) for Grasshopper Sparrow in 2012–2013 and 2013–2014, respectively. Weekly winter survival was lower with colder daily minimum temperatures for both species and in areas with taller shrubs for Grasshopper Sparrows, with the shrubs potentially increasing predation risk by providing perches for Loggerhead Shrikes (Lanius ludovicianus). Our results highlight the need to maintain healthy grass structure in wintering areas to provide birds with food, protection from predators, and adequate cover from inclement weather. Our results also demonstrate that the presence of shrubs can lower winter survival, and suggest that shrub encroachment into the winter habitat of these sparrows may be an important driver of their population declines. Shrub removal could increase survival of wintering sparrows in the Chihuahuan Desert by reducing availability of perches for avian predators, thus reducing predation risk.     

In vitro androgen metabolism in mouse kidney: High 3-keto-reductase (3α-hydroxysteroid dehydrogenase) activity relative to 5α-reductase

The $\text{in vitro}$ metabolism of testosterone and dihydrotestosterone was studied in slices and cell fractions of mouse kidney. When testosterone was used as substrate, very little metabolism to dihydrotestosterone occurred suggesting very low 5α-reductase activity. When dihydrotestosterone was substrate, it was rapidly converted to 5α-androstane-3α, 17β-diol by a potent 3-keto-reductase. Ninety-five percent of this latter enzyme is located in cytosol and it requires NADPH as cofactor. The 3-keto-reductase may exist in two molecular forms which can be separated by polyacrylamide gel electrophoresis. Form A and B have mean molecular radii which correspond to molecular weights of 38, 700 and 28, 700, respectively. Sufficient 3-keto-reductase activity is present in cytosol at 0°C to reduce physiological concentrations (2×10^?9 M) of dihydrotestosterone without the addition of cofactor. 3-Keto-reductase activity is higher in intact male than in castrate male or female mice and increases with androgen treatment.From these studies we conclude: (a) The virtual absence of 5α-reductase in mouse kidney is consistent with the thesis that testosterone rather than dihydrotestosterone may be the intracellular androgen in this organ. (b) Kinetic studies which depend upon the $\text{in vitro}$ uptake and retention of dihydrotestosterone by receptor proteins may be difficult to interpret due to rapid metabolism of ligand.     

Life cycle assessment of emerging environmental technologies in the early stage of development: A case study on nanostructured materials

The use of nanostructured materials has been recently proposed in the field of environmental nanoremediation. This approach consists in using nanomaterials not directly, but as building blocks for the design of nano‐porous micro‐dimensional systems, overcoming the eco‐ and health‐toxicology risks generally associated with the use of nano‐sized technologies. Herein we report the use of life cycle assessment (LCA) as an eco‐design tool for optimizing the production of cellulose nanosponges (CNS), nanostructured materials recently developed for water remediation purposes. LCA was applied from the acquisition of raw materials to the synthesis of CNS (from cradle‐to‐gate), considering three production systems, from the lab‐level to a modeled scale‐up system. The lab‐scale LCA identified the main environmental hotspots, namely the energy‐consuming steps and the final purification of the material (washing step). In a second lab‐scale production, an improvement action could be implemented, switching the washing solvent from methanol to water and decreasing the washing temperature. A second LCA showed a reduced contribution to the impacts from the materials, while the global impacts remained within the same order of magnitude. A simulated scale‐up of the process allowed to optimize the energy‐consuming steps and the water consumption, through internal recycling. A third LCA assessed the resulting benefits and a decrease in the global impacts by two orders of magnitude. Our study contributes to the discussion of LCA community, providing a focus on the importance of scaling‐up of emerging technologies, namely nanostructured porous materials, highlighting the benefits of a LCA based approach since the very beginning of product design (eco‐design).     

Traumatic brain injury as a risk factor for Alzheimer disease. Comparison of two retrospective autopsy cohorts with evaluation of ApoE genotype

Background and Purpose  

The impact of traumatic brain injury (TBI) on the pathogenesis of Alzheimer disease (AD) is still controversial. The aim of our retrospective autopsy study was to assess the impact of TBE and ApoE allele frequency on the development of AD.     

Increased Zinc and Manganese in Parallel with Neurodegeneration,Synaptic Protein Changes and Activation of Akt/GSK3 Signaling in Ovine CLN6 Neuronal Ceroid Lipofuscinosis

Mutations in the CLN6 gene cause a variant late infantile form of neuronal ceroid lipofuscinosis (NCL; Batten disease). CLN6 loss leads to disease clinically characterized by vision impairment, motor and cognitive dysfunction, and seizures. Accumulating evidence suggests that alterations in metal homeostasis and cellular signaling pathways are implicated in several neurodegenerative and developmental disorders, yet little is known about their role in the NCLs. To explore the disease mechanisms of CLN6 NCL, metal concentrations and expression of proteins implicated in cellular signaling pathways were assessed in brain tissue from South Hampshire and Merino CLN6 sheep. Analyses revealed increased zinc and manganese concentrations in affected sheep brain in those regions where neuroinflammation and neurodegeneration first occur. Synaptic proteins, the metal-binding protein metallothionein, and the Akt/GSK3 and ERK/MAPK cellular signaling pathways were also altered. These results demonstrate that altered metal concentrations, synaptic protein changes, and aberrant modulation of cellular signaling pathways are characteristic features in the CLN6 ovine form of NCL.