Effects of native plants extracts from Córdoba Argentina over foraging activity of the cutting ant Acromyrmex lundi (Guérin)

In the search for new alternatives for insect pest management, natural products from plants are an option currently studied for being substances of low toxicity and biodegradable. The leaf-cutting ant Acromyrmex lundi is a very important herbivorous species in the Argentine Chaco phytogeographic region as it can cut various parts of plants and attack almost all cultivated species. The objectives of this study were: 1. determine the effect of plant extracts native of Córdoba-Argentina on the foraging activity of A. lundi in an artificial nest. 2. evaluate the crude extract with highest activity in foraging activity field tests. Extracts were prepares with aerial parts of plants belonging to 28 botanical families. In the laboratory, an artificial nest was installed, which consisted of a main chamber where the queen, the immature and the fungus remained, and smaller chambers that operated as dump and foraging areas. The work was carried out under controlled conditions (27°C, 12:12 hs light/darkness and Hº 25± 3). In free-choice tests, 8 discs of rose leaves of 1 cm of diameter were impregnated with 10μl per cm2 of a 1% solution (10 ug / ul) of each extract or solvent (control). The Inhibitory Dose 50 (ID50) was determined for all the extracts that showed 100% repellency. Aristolochia argentina Griseb. showed the lowest DI50 values, for what it was chosen for field trials. Rose leaves treated with A. argentina extract (1% and 5%) and others with acetone (control) were placed on either side of an actively foraging path of six active nests of A. lundi, 50cm from the nest opening. The percentage of removed material was registered within two hours of observation and on two consecutive days, ending the trial when removed 50% of the total substrate provided. Also, foraging activity was determined by counting at a fixed point and for a period of three minutes, the number of workers who went towards the mound charged. In field trials, the 1% extract of A. argentina (n = 6) did not affect foraging activity (P> 0.05), whereas the 5% dose (n = 5) showed significant differences between treatments (P <0.05). From these preliminary results, future studies arise to deepen different effects of the compound oriented to leaf-cutting ants management.Fil: Nolli, L.C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Entomología; Argentina.Fil: Nolli, L.C. Centro de Investigaciones Entomológicas de Córdoba; Argentina.Fil: Buffa, L.M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Entomología; Argentina.Fil: Buffa, L.M. Centro de Investigaciones Entomológicas de Córdoba; Argentina.Fil: Defagó, M. T. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Entomología; Argentina.Fil: Defagó, M. T. Centro de Investigaciones Entomológicas de Córdoba; Argentina.Fil: Diaz Napal, G. Universidad Católica de Córdoba. Facultad de Ciencias Químicas. Laboratorio de Química Fina y Productos Naturales; Argentina.Fil: Palacios, S. M. Universidad Católica de Córdoba. Facultad de Ciencias Químicas. Laboratorio de Química Fina y Productos Naturales; Argentina.Zoología, Ornitología, Entomología, Etologí

Pharmacological prevention of type 2 diabetes.

audience: researcher, professional, studen

Áfidos (Hemptera, Aphididae) de interés económico en la provincia de Santa Cruz

Los pulgones o áfidos (Aphididae), debido a sus características biológicas e impacto económico en los cultivos, representan uno de los grupos de insectos más importantes desde el punto de vista agronómico. Por ello, es de gran importancia toda información relacionada con la distribución de cada especie y las relaciones con sus plantas hospedantes. Con el propósito de conocer la riqueza de áfidos de interés económico y las plantas cultivadas que colonizan en la provincia de Santa Cruz, se realizaron muestreos durante las estaciones favorables de 2003-2004 (primavera-verano) en ambientes antropizados representativos de dicha provincia. Se recolectaron los áfidos que colonizaban árboles de interés forestal y frutícola, cultivos hortícolas, plantas ornamentales y otras especies cultivadas con distintos propósitos. En total, se registraron 109 asociaciones áfido-planta cultivada, en las que participaron 49 especies de áfidos y 76 de plantas. El 59% de estas asociaciones incluyeron plantas ornamentales y de interés forestal; el 27% plantas de interés hortícola, especies frutales y cultivadas como aromáticas; el 15% restante comprendió otras asociaciones con especies botánicas aprovechadas como forrajeras, pasturas, etc. También se encontraron áfidos conocidos como eficientes vectores de virus fitopatógenos

Lipolytic enzymes and hydrolytic rancidity

Lipolysis, the enzymic hydrolysis of milk lipids to free fatty acids and partial glycerides, is a constant concern to the dairy industry because of the detrimental effcts it can have on the flvor and other properties of milk and milk products. However, free fatty acids also contribute to the desirable flavor of milk and milk products when present at low concentrations and, in some cheeses, when present at high concentrations. The enzymes responsible for the detrimental effects of lipolysis are of two main types: those indigenous to milk, and those of microbial origin. The major indigenous milk enzyme is lipoprotein lipase. It is active on the fat in natural milk fat globules only after their disruption by physical treatments or if certain blood serum lipoproteins are present. The major microbial lipases are produced by psychrotrophic bacteria. Many of these enzymes are heat stable and are particularly significant in stored products. Human milk differs from cows' milk in that it contains two lipases, a lipoprotein lipase and a bile salt-stimulated lipase. The ability of the latter to cause considerable hydrolysis of ingested milk lipids has important nutritional implications

Multi-messenger Observations of a Binary Neutron Star Merger

International audienceOn 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta