Wasmannia Forel (Hymenoptera: Formicidae: Myrmicinae) in Argentina: systematics and distribution

The ant genus Wasmannia is endemic to the Neotropics, with 10 species occurring within the presumptive native range for the genus from Mexico to Argentina. Only the little fire ant, Wasmannia auropunctata is widely distributed being present from central-eastern Argentina to Bermuda, and has become infamous due to its recent worldwide expansion and status as an invasive pest. The objective of this work was to study the systematics and distribution of Wasmannia in its southern limit of distribution in Argentina. Out of the three species reported so far for Argentina, only W. auropunctata was found to be widely distributed, but abundant only in disturbed habitats mostly in the Northeast. Herein, the distribution of Wasmannia auropunctata is extended and its queen and male castes are redescribed, along with descriptions of gynandromorphs (specimens with left side of the head similar to a male and right side similar to a queen). Wasmannia sulcaticeps and W. williamsoni are much less common and widespread. W. sulcaticepsis mostly found in mountain forests in northwestern Argentina, whereas W. williamsoni is only found in shrublands and grasslands in central eastern Argentina, and most frequently in mountain grasslands. Both species overlap with W. auropunctata, which is more common in the lowlands, between approximately 400 and 1000 m elevation. The queen of W. williamsoni is described and queen and male of W. sulcaticeps are redescribed. A new species, Wasmannia longiseta n. sp. Cuezzo and Calcaterra, recently found in northeastern Argentina is described based on worker morphology. Wasmannia rochai is recorded for the first time in Misiones, extending its distribution range from São Paulo (Brazil) to Misiones in northeastern Argentina. A key to the worker caste is provided. A cladistic analysis based on discrete and continuous morphological characters is presented as a first attempt to clarify the phylogenetic relationships between the known species of Wasmannia.Fil: Cuezzo, Fabiana del Carmen. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo. Instituto Superior de Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Calcaterra, Luis Alberto. Fundación Para El Estudio de Especies Invasivas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chifflet, Lucila. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Follet, P. A.. Pacific Basin Agricultural Research Center; Estados Unido

Contribution of Color Information in Visual Saliency Model for Videos

International audienceMuch research has been concerned with the contribution of the low level features of a visual scene to the deployment of visual attention. Bottom-up saliency models have been developed to predict the location of gaze according to these features. So far, color besides to brightness, contrast and motion is considered as one of the primary features in computing bottom-up saliency. However, its contribution in guiding eye movements when viewing natural scenes has been debated. We investigated the contribution of color information in a bottom-up visual saliency model. The model efficiency was tested using the experimental data obtained on 45 observers who were eye tracked while freely exploring a large data set of color and grayscale videos. The two datasets of recorded eye positions, for grayscale and color videos, were compared with a luminance-based saliency model. We incorporated chrominance information to the model. Results show that color information improves the performance of the saliency model in predicting eye positions

A novel causal mechanism for grey squirrel bark stripping: The Calcium Hypothesis

AbstractGrey squirrels, Sciurus carolinensis, damage trees in the UK by stripping bark and eating the underlying phloem; squirrel motivation for damage is, however, unknown. Damage can result in deterioration of timber quality and a significant economic toll on the forestry industry. Prediction of severe damage followed by targeted killing of squirrels is the current recommended management option. However, the use of warfarin (an anticoagulant poison) is now restricted in the UK and other more humane methods of killing are labour-intensive, so an alternative solution is needed. A better understanding of what motivates grey squirrels to strip bark may enable a preventive approach to be developed. Whilst the bark stripping literature has explored predictive factors affecting the likelihood of damage, causal understanding is lacking. The aim of this review is to introduce the Calcium Hypothesis as a possible explanation for bark stripping, with a view to informing the prevention of damage. The Calcium Hypothesis states that grey squirrels damage trees to ameliorate a calcium deficiency. The main predictive factors of bark stripping behaviour each inform and lend support to the Calcium Hypothesis. Calcium is stored in tree phloem, and damage increases with phloem width, providing squirrels with more calcium per unit area ingested. Calcium levels increase in trees as active growth resumes after winter dormancy, this occurs immediately prior to the main bark stripping season of May–July, and trees growing most vigorously are at increased risk of damage. It is likely grey squirrels also have a requirement for calcium during the bark stripping season. Adult females will be under post-parturition pressures such as lactation, and juveniles will be going through their main period of bone growth, both of which likely represent a requirement for calcium – which supports an observed positive correlation between juvenile abundance and bark stripping. A high autumnal seed crop increases juvenile recruitment the following spring, and could also induce a requirement for calcium to a population due to the high phosphorus to calcium ratio of seeds. To further investigate the hypothesis, the extent to which grey squirrels can utilise calcium oxalate, as calcium occurs in bark, should be determined, and also the extent to which grey squirrels undergo seasonal periods of calcium deficiency. Increasing our causal understanding of bark stripping could inform the future development of preventive measures to aid forest management

A phase i pharmacokinetic study of the vascular disrupting agent ombrabulin (AVE8062) and docetaxel in advanced solid tumours

Background: The vascular disrupting agent ombrabulin shows synergy with docetaxel in vivo. Recommended phase II doses were determined in a dose escalation study in advanced solid tumours. Methods: Ombrabulin (30-min infusion, day 1) followed by docetaxel (1-h infusion, day 2) every 3 weeks was explored. Ombrabulin was escalated from 11.5 to 42 mg m -2 with 75 mg m -2 docetaxel, then from 30 to 35 mg m -2 with 100 mg m -2 docetaxel. Recommended phase II dose cohorts were expanded. Results: Fifty-eight patients were treated. Recommended phase II doses were 35 mg m -2 ombrabulin with 75 mg m -2 docetaxel (35/75 mg m -2; 13 patients) and 30 mg m -2 ombrabulin with 100 mg m -2 docetaxel (30/100 mg m -2; 16 patients). Dose-limiting toxicities were grade 3 fatigue (two patients; 42/75, 35/100), grade 3 neutropaenic infection (25/75), grade 3 headache (42/75), grade 4 febrile neutropaenia (30/100), and grade 3 thrombosis (35/100). Toxicities were consistent with each agent; mild nausea/vomiting, asthaenia/fatigue, alopecia, and anaemia were common, as were neutropaenia and leukopaenia. Diarrhoea, nail disorders and neurological symptoms were frequent at 100 mg m -2 docetaxel. Pharmacokinetic analyses did not show any relevant drug interactions. Ten patients had partial responses (seven at 30 mg m -2 ombrabulin), eight lasting >3 months. Conclusions: Sequential administration of ombrabulin with 75 or 100 mg m -2 docetaxel every 3 weeks is feasible

PrP Expression, PrPSc Accumulation and Innervation of Splenic Compartments in Sheep Experimentally Infected with Scrapie

BACKGROUND: In prion disease, the peripheral expression of PrP(C) is necessary for the transfer of infectivity to the central nervous system. The spleen is involved in neuroinvasion and neural dissemination in prion diseases but the nature of this involvement is not known. The present study undertook the investigation of the spatial relationship between sites of PrP(Sc) accumulation, localisation of nerve fibres and PrP(C) expression in the tissue compartments of the spleen of scrapie-inoculated and control sheep. METHODOLOGY/PRINCIPAL FINDINGS: Laser microdissection and quantitative PCR were used to determine PrP mRNA levels and results were compared with immunohistochemical protocols to distinguish PrP(C) and PrP(Sc) in tissue compartments of the spleen. In sheep experimentally infected with scrapie, the major sites of accumulation of PrP(Sc) in the spleen, namely the lymphoid nodules and the marginal zone, expressed low levels of PrP mRNA. Double immunohistochemical labelling for PrP(Sc) and the pan-nerve fibre marker, PGP, was used to evaluate the density of innervation of splenic tissue compartments and the intimacy of association between PrP(Sc) and nerves. Some nerve fibres were observed to accompany blood vessels into the PrP(Sc)-laden germinal centres. However, the close association between nerves and PrP(Sc) was most apparent in the marginal zone. Other sites of close association were adjacent to the wall of the central artery of PALS and the outer rim of germinal centres. CONCLUSIONS/SIGNIFICANCE: The findings suggest that the degree of PrP(Sc) accumulation does not depend on the expression level of PrP(C). Though several splenic compartments may contribute to neuroinvasion, the marginal zone may play a central role in being the compartment with most apparent association between nerves and PrP(Sc)

Fluorescent Risedronate Analogues Reveal Bisphosphonate Uptake by Bone Marrow Monocytes and Localization Around Osteocytes In Vivo

Bisphosphonates are effective antiresorptive agents owing to their bone-targeting property and ability to inhibit osteoclasts. It remains unclear, however, whether any non-osteoclast cells are directly affected by these drugs in vivo. Two fluorescent risedronate analogues, carboxyfluorescein-labeled risedronate (FAM-RIS) and Alexa Fluor 647–labeled risedronate (AF647-RIS), were used to address this question. Twenty-four hours after injection into 3-month-old mice, fluorescent risedronate analogues were bound to bone surfaces. More detailed analysis revealed labeling of vascular channel walls within cortical bone. Furthermore, fluorescent risedronate analogues were present in osteocytic lacunae in close proximity to vascular channels and localized to the lacunae of newly embedded osteocytes close to the bone surface. Following injection into newborn rabbits, intracellular uptake of fluorescently labeled risedronate was detected in osteoclasts, and the active analogue FAM-RIS caused accumulation of unprenylated Rap1A in these cells. In addition, CD14high bone marrow monocytes showed relatively high levels of uptake of fluorescently labeled risedronate, which correlated with selective accumulation of unprenylated Rap1A in CD14+ cells, as well as osteoclasts, following treatment with risedronate in vivo. Similar results were obtained when either rabbit or human bone marrow cells were treated with fluorescent risedronate analogues in vitro. These findings suggest that the capacity of different cell types to endocytose bisphosphonate is a major determinant for the degree of cellular drug uptake in vitro as well as in vivo. In conclusion, this study shows that in addition to bone-resorbing osteoclasts, bisphosphonates may exert direct effects on bone marrow monocytes in vivo. © 2010 American Society for Bone and Mineral Researc

A new murine model of osteoblastic/osteolytic lesions from human androgen-resistant prostate cancer

BACKGROUND: Up to 80% of patients dying from prostate carcinoma have developed bone metastases that are incurable. Castration is commonly used to treat prostate cancer. Although the disease initially responds to androgen blockade strategies, it often becomes castration-resistant (CRPC for Castration Resistant Prostate Cancer). Most of the murine models of mixed lesions derived from prostate cancer cells are androgen sensitive. Thus, we established a new model of CRPC (androgen receptor (AR) negative) that causes mixed lesions in bone. METHODS: PC3 and its derived new cell clone PC3c cells were directly injected into the tibiae of SCID male mice. Tumor growth was analyzed by radiography and histology. Direct effects of conditioned medium of both cell lines were tested on osteoclasts, osteoblasts and osteocytes. RESULTS: We found that PC3c cells induced mixed lesions 10 weeks after intratibial injection. In vitro, PC3c conditioned medium was able to stimulate tartrate resistant acid phosphatase (TRAP)-positive osteoclasts. Osteoprotegerin (OPG) and endothelin-1 (ET1) were highly expressed by PC3c while dikkopf-1 (DKK1) expression was decreased. Finally, PC3c highly expressed bone associated markers osteopontin (OPN), Runx2, alkaline phosphatase (ALP), bone sialoprotein (BSP) and produced mineralized matrix in vitro in osteogenic conditions. CONCLUSIONS: We have established a new CRPC cell line as a useful system for modeling human metastatic prostate cancer which presents the mixed phenotype of bone metastases that is commonly observed in prostate cancer patients with advanced disease. This model will help to understand androgen-independent mechanisms involved in the progression of prostate cancer in bone and provides a preclinical model for testing the effects of new treatments for bone metastases