Comparative study of honey bee production with one and three queens by beehive in nueva imperial, IX region, Chile

In the Region of La Araucanía tests have been made where the production of honey of double queen beehives was compared to single queen beehives, with encouraging results. This motivated the accomplishment of this study in the zone of Nueva Imperial, which compared the conventional production of honey of triple queen systems and systems with one queen by beehive. For the accomplishment of this study 12 beehives were used, nine were grouped to form the triple queen systems and the remaining three with one queen were used as control. The research began on November 4th 2004, with weekly visits to control the factors that could affect the honey productions. The crop was made on January 11th 2005, reaching a honey production of 85 kg average for triple queens systems, which was significantly greater to the production obtained by the systems with a single queen which reached 19,17 kg of honey average.En la Región de La Araucanía se han realizado ensayos donde se comparó la producción de miel de colmenas doble reina y colmenas de una sola reina, con resultados alentadores. Esto motivó la realización de este estudio en la zona de Nueva Imperial, el cual comparó la producción de miel de sistemas de triple reina y sistemas convencionales con una reina por colmena. Para la realización de este estudio se utilizaron 12 colmenas, de las cuales nueve se agruparon para formar los sistemas triple reina, y las tres restantes con una reina fueron utilizadas como testigo. La investigación comenzó el 4 de noviembre del 2004, con visitas semanales, para controlar los factores que pudieran incidir en la producción de miel. La cosecha se realizó el 11 de enero de 2005, alcanzándose producciones promedio de 85 kg de miel para los sistemas triple reina, lo cual fue significativamente mayor a la producción lograda por los sistemas con una sola reina que alcanzaron 19,17 kg de miel promedio

Proposal for a method to estimate nutrient shock effects in bacteria

Plating methods are still the golden standard in microbiology; however, some studies have shown that these techniques can underestimate the microbial concentrations and diversity. A nutrient shock is one of the mechanisms proposed to explain this phenomenon. In this study, a tentative method to assess nutrient shock effects was tested. Findings To estimate the extent of nutrient shock effects, two strains isolated from tap water (Sphingomonas capsulata and Methylobacterium sp.) and two culture collection strains (E. coli CECT 434 and Pseudomonas fluorescens ATCC 13525) were exposed both to low and high nutrient conditions for different times and then placed in low nutrient medium (R2A) and rich nutrient medium (TSA). The average improvement (A.I.) of recovery between R2A and TSA for the different times was calculated to more simply assess the difference obtained in culturability between each medium. As expected, A.I. was higher when cells were plated after the exposition to water than when they were recovered from high-nutrient medium showing the existence of a nutrient shock for the diverse bacteria used. S. capsulata was the species most affected by this phenomenon. This work provides a method to consistently determine the extent of nutrient shock effects on different microorganisms and hence quantify the ability of each species to deal with sudden increases in substrate concentration. <br/

O-Glycosylation Regulates Ubiquitination and Degradation of the Anti-Inflammatory Protein A20 to Accelerate Atherosclerosis in Diabetic ApoE-Null Mice

Background: Accelerated atherosclerosis is the leading cause of morbidity and mortality in diabetic patients. Hyperglycemia is a recognized independent risk factor for heightened atherogenesis in diabetes mellitus (DM). However, our understanding of the mechanisms underlying glucose damage to the vasculature remains incomplete. Methodology/Principal Findings: High glucose and hyperglycemia reduced upregulation of the NF-κB inhibitory and atheroprotective protein A20 in human coronary endothelial (EC) and smooth muscle cell (SMC) cultures challenged with Tumor Necrosis Factor alpha (TNF), aortae of diabetic mice following Lipopolysaccharide (LPS) injection used as an inflammatory insult and in failed vein-grafts of diabetic patients. Decreased vascular expression of A20 did not relate to defective transcription, as A20 mRNA levels were similar or even higher in EC/SMC cultured in high glucose, in vessels of diabetic C57BL/6 and FBV/N mice, and in failed vein grafts of diabetic patients, when compared to controls. Rather, decreased A20 expression correlated with post-translational O-Glucosamine-N-Acetylation (O-GlcNAcylation) and ubiquitination of A20, targeting it for proteasomal degradation. Restoring A20 levels by inhibiting O-GlcNAcylation, blocking proteasome activity, or overexpressing A20, blocked upregulation of the receptor for advanced glycation end-products (RAGE) and phosphorylation of PKCβII, two prime atherogenic signals triggered by high glucose in EC/SMC. A20 gene transfer to the aortic arch of diabetic ApoE null mice that develop accelerated atherosclerosis, attenuated vascular expression of RAGE and phospho-PKCβII, significantly reducing atherosclerosis. Conclusions: High glucose/hyperglycemia regulate vascular A20 expression via O-GlcNAcylation-dependent ubiquitination and proteasomal degradation. This could be key to the pathogenesis of accelerated atherosclerosis in diabetes

Nuclear factor-erythroid-2 related transcription factor-1 (Nrf1) is regulated by O-GlcNAc transferase

The Nrf1 (Nuclear factor E2-related factor 1) transcription factor performs a critical role in regulating cellular homeostasis. Using a proteomic approach, we identified Host Cell Factor-1 (HCF1), a co-regulator of transcription, and O-GlcNAc transferase (OGT), the enzyme that mediates protein O-GlcNAcylation, as cellular partners of Nrf1a, an isoform of Nrf1. Nrf1a directly interacts with HCF1 through the HCF1 binding motif (HBM), while interaction with OGT is mediated through HCF1. Overexpression of HCF1 and OGT leads to increased Nrf1a protein stability. Addition of O-GlcNAc decreases ubiquitination and degradation of Nrf1a. Transcriptional activation by Nrf1a is increased by OGT overexpression and treatment with PUGNAc. Together, these data suggest that OGT can act as a regulator of Nrf1a

Lines Of Curvature On Surfaces Immersed In ℝ4

The differential equation of the lines of curvature for immersions of surfaces into ℝ4 is established. It is shown that, for a class of generic immersions of a surface into ℝ4 in the Cr-topology, r ≥ 4, all of the umbilic points are locally topologically stable. This type of umbilic points is described. © 1997, Sociedade Brasileira de Matemática.282233251Burnside, W.S., Panton, A.W., (1912) The Theory of Equations, , [B-P] Dover Publications, Inc. New YorkGuadalupe, I., Gutiérrez, C., Sotomayor, J., Tribuzy, R., Principal Lines on Surfaces Minimally Immersed in Constantly Curved 4-spaces (1987) Dynamical Systems and Bifurcation Theory, Pitman Research Notes in Mathematics Series, 160, pp. 91-120. , [GGST]Gutierrez, C., Sotomayor, J., Principal Lines on Surfaces Immersed with Constant Mean Curvature (1986) Trans, of the Ame. Math. Soc., 293 (2), pp. 751-766. , [G-S]Jacobowitz, H., The Gauss-Codazzi Equations (1982) Tensor, N., S., 39, pp. 15-22. , [Jac]Little, J.A., On Singularities of Submanifolds of a Higher Dimensional Euclidean Space (1969) Ann. Mat. Pura App., 83, pp. 261-335. , [Lit]Palis, J., De Melo, W., (1982) Geometric Theory of Dynamical Systems, , [M-P] Springer-VerlagRamírez-Galarza, A., Sánchez-Bringas, F., Lines of Curvature near Umbilic Points on Surfaces Immersed in ℝ4 (1995) Annals of Global Analysis and Geometry, 13, pp. 129-140. , [R-S]Spivak, M., (1979) A Comprehensive Introduction to Differential Geometry, 5. , [Spi] Publish or Perish Inc., Berkele

Invasion of a rocky intertidal shore by the tunicate Pyura praeputialis in the Bay of Antofagasta, Chile

Invasion by marine nonindigenous species (NIS) is a spread phenomenon. The tunicate Pyura praeputialis shows pronounced disjoint geographical distribution: along thousands of kilometers in wave-swept headlands on the southeastern coast of Australia, from where it appears to have originated, and exclusively along 60–70 km inside the Bay of Antofagasta, Chile. mtDNA sequences suggested that the species invaded this rocky shore recently. We used field manipulations and juvenile P. praeputialis transplant techniques to test hypotheses regarding the capacity of the tunicate to survive and grow at different sites and tidal heights inside and outside Antofagasta, and its competitive performance for primary space (inside the Bay) against the native mussel Perumytilus purpuratus. We conclude that survival and growth of P. praeputialis showed no significant differences among sites inside and outside the Bay, and suggest that the restrictive distribution of the species in Chile is caused by a specific oceanographic retention mechanism and/or its brief larval dispersal. We demonstrated that, inside the Bay, P. praeputialis outcompetes Perumytilus from the Mid–Low intertidal, constraining Perumytilus to the Upper Mid-Intertidal, modifying the local pattern of intertidal zonation. We show that predation on P. praeputialis juveniles by starfish and snails constitutes a regulatory mechanism for the setting of its low intertidal limit. Major ecological impacts caused by NIS invasions to rocky shores by aggressive primary space users may result in negative aspects, but also may contribute to biodiversity enhancement. We call attention to the need for increment manipulations and testing of ecological hypotheses regarding marine NIS