Two new Andean species of Neocorynura (Hymenoptera: Halictidae: Augochlorini) with notes on their biology

We describe and illustrate the male, female, and pupa of two new species of Neocorynura from the Colombian Andes, and provide information on their nesting behavior, host plants and social organization. Nests of Neocorynura iguaquensis sp. nov. Smith‐Pardo & Gonzalez and N. muiscae sp. nov. Smith‐Pardo & Gonzalez were found in flat or vertical banks, and contained one to three adult females. The percentage of multi‐female nests varied considerably from 8.3% to 40% of the total of dissected nests at different times in 2000 and 2003. The ovarian development, wing and mandibular wear of females in the nests with two or more females indicated that they were the offspring that remained in the nest before dispersal or a mother and a newly emerged daughter. Pollen taken from the nest cells and scopae of museum specimens showed that both species rely heavily on pollen of asteraceans and may be active year‐round. Details on the nest architecture and comments on the phylogenetic placement of both species are also provided. Direct observations on the multi‐female nests are required to determine whether or not such nests contain temporary assemblages or truly semisocial colonies.

Resumen

Describimos e ilustramos el macho, hembra y pupa de dos especies nuevas de Neocorynura de los Andes colombianos, y proporcionamos información sobre su biología de nidificación, plantas hospederas y organización social. Los nidos de Neocorynura iguaquensis sp. nov. Smith‐Pardo & Gonzalez y N. muiscae sp. nov. Smith‐Pardo & Gonzalez fueron encontrados en el suelo, en áreas planas o barrancos verticales, y tenían de una a tres hembras adultas. El porcentaje de nidos con más de una hembra varió considerablemente desde 8.3% al 40% del total de nidos disectados a diferentes meses en el año 2000 y 2003. El desarrollo ovárico, desgaste de las alas y mandíbulas de las hembras en los nidos con dos o más hembras indicaron que ellas fueron las crías que permanecieron en el nido antes de dispersarse o una madre con la hija recién nacida. El polen tomado de las celdas de cría y escopas de especimenes de museo mostró que ambas especies dependen principalmente de asteraceas y que podrían estar activas todo el año. También oferecemos detalles de la arquitectura del nidos y comentarios sobre la posición filogenética de ambas especies. Observaciones directas de los nido con más de una hembra son necesarias para determinar si tales nidos son agrupaciones temporales o verdaderas colonias semisociales.     

Inorganic phosphate enhances sensitivity of human osteosarcoma U2OS cells to doxorubicin via a p53‐dependent pathway

Osteosarcoma is the most common malignant primary bone tumor in children and adolescents. The clinical outcome for osteosarcoma remains discouraging despite aggressive surgery and intensive radiotherapy and chemotherapy regimens. Thus, novel therapeutic approaches are needed. Previously, we have shown that inorganic phosphate (Pi) inhibits proliferation and aggressiveness of human osteosarcoma U2OS cells identifying adenylate cyclase, beta3 integrin, Rap1, ERK1/2 as proteins whose expression and function are relevantly affected in response to Pi. In this study, we investigated whether Pi could affect chemosensitivity of osteosarcoma cells and the underlying molecular mechanisms. Here, we report that Pi inhibits proliferation of p53‐wild type U2OS cells (and not of p53‐null Saos and p53‐mutant MG63 cells) by slowing‐down cell cycle progression, without apoptosis occurrence. Interestingly, we found that Pi strongly enhances doxorubicin‐induced cytotoxicity in U2OS, and not in Saos and MG63 cells, by apoptosis induction, as revealed by a marked increase of sub‐G1 population, Bcl‐2 downregulation, caspase‐3 activation, and PARP cleavage. Remarkably, Pi/doxorubicin combination‐induced cytotoxicity was accompanied by an increase of p53 protein levels and of p53 target genes mdm2, p21 and Bax, and was significantly reduced by the p53 inhibitor pifithrine‐alpha. Moreover, the doxorubicin‐induced cytotoxicity was associated with ERK1/2 pathway inhibition in response to Pi. Altogether, our data enforce the evidence of Pi as a novel signaling molecule capable of inhibiting ERK pathway and inducing sensitization to doxorubicin of osteosarcoma cells by p53‐dependent apoptosis, implying that targeting Pi levels might represent a rational strategy for improving osteosarcoma therapy. J. Cell. Physiol. 228: 198–206, 2013. © 2012 Wiley Periodicals, Inc.     

Structural and Compositional Changes in Erythrocyte Membrane of Obese Compared to Normal-Weight Adolescents

Unhealthy dietary habits are key determinants of obesity in adolescents. Assuming that dietary fat profile influences membrane lipid composition, the aim of this study was to analyze structural changes in the erythrocyte membrane of obese compared to normal-weight adolescents. The study was conducted in a group of 11 obese and 11 normal-weight adolescent subjects. The lipid profile, lipid peroxidation and acetylcholinesterase enzyme (AChE) activity were analyzed by conventional methods. The structural properties of reconstituted erythrocyte membrane were characterized by X-ray diffraction. Erythrocyte membrane from obese adolescents had a lipid profile characterized by a higher cholesterol/phospholipid ratio, an increase in saturated fatty acid and a decrease in monounsaturated and n-6 polyunsaturated fatty acid concentrations. Differences in lipid content were associated with changes in the structural properties of reconstituted membranes and the oxidative damage of erythrocyte membrane. The lower oxidative level shown in the obese group (0.15 ± 0.04 vs. 0.20 ± 0.06 nmol/mg for conjugated diene concentrations and 2.43 ± 0.25 vs. 2.83 ± 0.31 nmol/mg protein for malondialdehyde levels) was related to a lower unsaturation index. These changes in membrane structural properties were accompanied by a lower AChE activity (1.64 ± 0.13 vs. 1.91 ± 0.24 nmol AChE/[min mg protein]) in the obese group. The consequences of unhealthy dietary habits in adolescents are reflected in the membrane structural properties and may influence membrane-associated protein activities and functions.     

Interspecific relationships in co‐occurring populations of social parasites and their host ants

Myrmica ant colonies host numerous insect species, including the larvae of Maculinea butterflies and Microdon myrmicae hoverflies. Little is known about the interspecific relationships among these social parasites and their host ants occurring in sympatric populations. We investigated communities of social parasites to assess the strategies allowing them to share the same pool of resources (i.e. Myrmica colonies). The present study was carried out at five sites inhabited by different social parasite communities, each comprising varying proportions of Maculinea teleius, Maculinea nausithous, Maculinea alcon, and Microdon myrmicae. We investigated their spatial distributions, host segregation, the degree of chemical similarity between social parasites and hosts, and temporal overlaps in colony resource exploitation. Spatial segregation among social parasites was found in two populations and it arises from microhabitat preferences and biological interactions. Local conditions can drive selection on one social parasite to use a Myrmica host species that is not exploited by other social parasites. Myrmica scabrinodis and Myrmica rubra nests infested by larvae of two social parasite species were found and the most common co‐occurrence was between Ma. teleius and Mi. myrmicae. The successful coexistence of these two species derives from their exploitation of the host colony resources at different times of the year. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 699–709.     

Application of Hazard Analysis and Critical Control Points (HACCP) to the Cultivation Line of Mushroom and Other Cultivated Edible Fungi

The Hazard analysis and critical control points (HACCP) is a preventive system which seeks to ensure food safety and security. It allows product protection and correction of errors, improves the costs derived from quality defects and reduces the final overcontrol. In this paper, the system is applied to the line of cultivation of mushrooms and other edible cultivated fungi. From all stages of the process, only the reception of covering materials (stage 1) and compost (stage 3), the pre-fruiting and induction (step 6) and the harvest (stage 7) have been considered as critical control point (CCP). The main hazards found were the presence of unauthorized phytosanitary products or above the permitted dose (stages 6 and 7), and the presence of pathogenic bacteria (stages 1 and 3) and/or heavy metals (stage 3). The implementation of this knowledge will allow the self-control of their productions based on the system HACCP to any plant dedicated to mushroom or other edible fungi cultivation.     

FNDC5/Irisin Is Not Only a Myokine but Also an Adipokine

Exercise provides clear beneficial effects for the prevention of numerous diseases. However, many of the molecular events responsible for the curative and protective role of exercise remain elusive. The recent discovery of FNDC5/irisin protein that is liberated by muscle tissue in response to exercise might be an important finding with regard to this unsolved mechanism. The most striking aspect of this myokine is its alleged capacity to drive brown-fat development of white fat and thermogenesis. However, the nature and secretion form of this new protein is controversial. The present study reveals that rat skeletal muscle secretes a 25 kDa form of FNDC5, while the 12 kDa/irisin theoretical peptide was not detected. More importantly, this study is the first to reveal that white adipose tissue (WAT) also secretes FNDC5; hence, it may also behave as an adipokine. Our data using rat adipose tissue explants secretomes proves that visceral adipose tissue (VAT), and especially subcutaneous adipose tissue (SAT), express and secrete FNDC5. We also show that short-term periods of endurance exercise training induced FNDC5 secretion by SAT and VAT. Moreover, we observed that WAT significantly reduced FNDC5 secretion in fasting animals. Interestingly, WAT of obese animals over-secreted this hormone, which might suggest a type of resistance. Because 72% of circulating FNDC5/irisin was previously attributed to muscle secretion, our findings suggest a muscle-adipose tissue crosstalk through a regulatory feedback mechanism.     

Synthetic Cyclolipopeptides Selective against Microbial,Plant and Animal Cell Targets by Incorporation of D-Amino Acids or Histidine

Cyclolipopeptides derived from the antimicrobial peptide c(Lys-Lys-Leu-Lys-Lys-Phe-Lys-Lys-Leu-Gln) (BPC194) were prepared on solid-phase and screened against four plant pathogens. The incorporation at Lys⁵ of fatty acids of 4 to 9 carbon atoms led to active cyclolipopeptides. The influence on the antimicrobial activity of the Lys residue that is derivatized was also evaluated. In general, acylation of Lys¹, Lys² or Lys⁵ rendered the sequences with the highest activity. Incorporation of a D-amino acid maintained the antimicrobial activity while significantly reduced the hemolysis. Replacement of Phe with a His also yielded cyclolipopeptides with low hemolytic activity. Derivatives exhibiting low phytotoxicity in tobacco leaves were also found. Interestingly, sequences with or without significant activity against phytopathogenic bacteria and fungi, but with differential hemolysis and phytotoxicity were identified. Therefore, this study represents an approach to the development of bioactive peptides with selective activity against microbial, plant and animal cell targets. These selective cyclolipopeptides are candidates useful not only to combat plant pathogens but also to be applied in other fields.     

A recipe for postfledging survival in great tits Parus major: be large and be early (but not too much)

Survival of juveniles during the postfledging period can be markedly low, which may have major consequences on avian population dynamics. Knowing which factors operating during the nesting phase affect postfledging survival is crucial to understand avian breeding strategies. We aimed to obtain a robust set of predictors of postfledging local survival using the great tit (Parus major) as a model species. We used mark–recapture models to analyze the effect of hatching date, temperatures experienced during the nestling period, fledging size and body mass on first‐year postfledging survival probability of great tit juveniles. We used data from 5192 nestlings of first clutches ringed between 1993 and 2010. Mean first‐year postfledging survival probability was 15.2%, and it was lower for smaller individuals, as well as for those born in either very early or late broods. Our results stress the importance of choosing an optimum hatching period, and raising large chicks to increase first‐year local survival probability in the studied population.