Public policy and partnership in research on biological control in France

Most public institutions and companies of plant protection industry have a favourable opinion of biological control; they feel concerned by the issue, but weakly engaged in its solution. Biological plant protection is however poorly developed in agriculture, the success of biological control being insufficiently known due to severe competition with chemical pesticides that are reliable, efficient, specific and safer for the environment. In this context, and to improve the implementation of biological control, the following actions are proposed:

1. more interdisciplinarity in research between agronomists, economists and biologists who have to take better advantage of the various concepts of evolutionary biology and to carry out more field experiments on a large scale;
2. wider and more integrated objectives: the successful control of a pest using biological means is not a sufficient aim. We absolutely need to consider all aspects of IPM, in particular resistance to pesticides, cultural means, plant breeding and all alternative biotechnical means;
3. larger partnership: during too many years, only researchers of public institutions were involved in biological control. Today, many partners, including public institutions (Plant Protection Service, Technical Institutes) and private companies (large and small) are engaged in alternative plant protection. To facilitate cooperation between them, a specific committee has been set up in France in order to coordinate experimentations for registration and quality control of biopesticides.

With such improved relationships between all partners, specific arguments and lobbying pressure should be stronger on the distribution and retailers of agricultural goods with a view to promoting plant products obtained via biological or integrated control methods and to seeking public understanding and support.     

Definitive Evidence for the existence of tight junctions in invertebrates

Extensive and unequivocal tight junctions are here reported between the lateral borders of the cellular layer that circumscribes the arachnid (spider) central nervous system. This account details the features of these structures, which form a beltlike reticulum that is more complex than the simple linear tight junctions hitherto found in invertebrate tissues and which bear many of the characteristics of vertebrate zonulae occludentes. We also provide evidence that these junctions form the basis of a permeability barrier to exogenous compounds. In thin sections, the tight junctions are identifiable as punctate points of membrane apposition; they are seen to exclude the stain and appear as election- lucent moniliform strands along the lines of membrane fusion in en face views of uranyl-calcium-treated tissues. In freeze-fracture replicas, the regions of close membrane apposition exhibit P-face (PF) ridges and complementary E-face (EF) furrows that are coincident across face transitions, although slightly offset with respect to one another. The free inward diffusion of both ionic and colloidal lanthanum is inhibited by these punctate tight junctions so that they appear to form the basis of a circumferential blood-brain barrier. These results support the contention that tight junctions exist in the tissues of the invertebrata in spite of earlier suggestions that (a) they are unique to vertebrates and (b) septate junctions are the equivalent invertebrate occluding structure. The component tight junctional 8- to 10-nm-particulate PF ridges are intimately intercalated with, but clearly distinct from, inverted gap junctions possessing the 13-nm EF particles typical of arthropods. Hence, no confusion can occur as to which particles belong to each of the two junctional types, as commonly happens with vertebrate tissues, especially in the analysis of developing junctions. Indeed, their coexistance in this way supports the idea, over which there has been some controversy, that the intramembrane particles making up these two junctional types must be quite distinct entities rather than products of a common precursor.     

CTL-associated antigen-4 ligation induces rapid T cell polarization that depends on phosphatidylinositol 3-kinase, Vav-1, Cdc42, and myosin light chain kinase

CTLA-4 can negatively regulate cytokine production and proliferation, increase motility, and override the TCR-induced stop-signal needed for stable T cell-APC conjugation. Despite this, little is known regarding whether CTLA-4 can alter T cell morphology and the nature of the signaling events that could account for this event. In this study, we demonstrate that anti-CTLA-4 and CD3/CTLA-4 induce rapid T cell polarization (i.e., within 15-30 min) with increases in lamellipodia, filopodia, and uropod formation. This was observed with anti-CTLA-4 and CD80-Ig ligation of CTLA-4, but not with anti-CD3 alone, or anti-CD3/CD28 coligation. Polarization required PI3K, the guanine nucleotide exchange factor Vav1, the GTP-binding protein Cdc42, as well as myosin L chain kinase. By contrast, a key downstream target of PI3K, protein kinase B, as well as Rho kinase and RhoA, were not needed. Our results demonstrate that CTLA-4 is a potent activator T cell polarization needed for motility, and this process involves specific set of signaling proteins that might contribute to coreceptor regulation of T cell function.     

Dosing Time Optimizes Sustained-Release Ketoprofen Treatment of Osteoarthritis

A double-blind randomized parallel-group trial was undertaken to evaluate the influence of the dosing time of sustained-release ketoprofen (SRK) on its acceptability and efficacy. The SRK was prescribed for 2 weeks (200 mg once a day) to 117 outpatients with osteoarthritis of the knee and/ or hip. One group received SRK in the morning (at 8 a.m.) and the other group in the evening (at 8 p.m.). The principal aim of the trial concerned the acceptability, whereas efficacy was its secondary aim. The principal trial criterion was defined as the number of spontaneous recordings of adverse effects. Results showed clearly that the acceptability of SRK in the SRK morning group was worse than that in the evening group (39% of patients with one or more adverse effects in the SRK morning group versus 19% in the evening group; p = 0.019). It is important to stress the difference concerning the number of adverse effects (48 for SRK morning group versus 23 for SRK evening group; p = 0.0234). The analgesic efficacy seemed to be similar, but one criterion was statistically significant: The duration of analgesic efficacy was more important for the SRK evening group than for the morning group (9.37 and 5.47 h, respectively; p = 0.001). To increase its acceptability, evening administration of SRK seems to be preferred over morning administration in osteoarthritis. However, other trials of the same type, assessing other antiinflammatory agents, are necessary before a general extrapolation of such results can be undertaken.     

Inducible expression of V600EBraf using tyrosinase-driven Cre recombinase results in embryonic lethality

We recently demonstrated that expression of ^V600EBraf in mature mouse melanocytes induces melanoma. Here, we show that expression of ^V600EBraf using the tyrosinase promoter leads to an unexpected embryonic lethality, with the animals dying before, at, or shortly after birth. The mice suffer from a range of developmental defects in the skin, the brain, the eyes and the heart, tissues that are normally colonized by melanocytes. We show that the ^V600EBraf expressing cells are potential melanocytic precursors that are fully transformed, suggesting that ^V600EBraf stimulates proliferation and blocks differentiation of these cells. Our data suggests that the presence of these cells in the organs that are normally occupied by melanocytes leads to severe developmental disruption, resulting in catastrophic defects and leading to death of the individual.     

Metastatic bladder cancer cells distinctively sense and respond to physical cues of collagen fibril-mimetic nanotopography

Tumor metastasis is characterized by enhanced invasiveness and migration of tumor cells through the extracellular matrix (ECM), resulting in extravasation into the blood and lymph and colonization at secondary sites. The ECM provides a physical scaffold consisting of components such as collagen fibrils, which have distinct dimensions at the nanoscale. In addition to the interaction of peptide moieties with tumor cell integrin clusters, the ECM provides a physical guide for tumor cell migration. Using nanolithography we set out to mimic the physical dimensions of collagen fibrils using lined nanotopographical silicon surfaces and to explore whether metastatic tumor cells are uniquely able to respond to these physical dimensions. Etched silicon surfaces containing nanoscale lined patterns with varying trench and ridge sizes (65–500 nm) were evaluated for their ability to distinguish between a non-metastatic (253J) and a highly metastatic (253J-BV) derivative bladder cancer cell line. Enhanced alignment was distinctively observed for the metastatic cell lines on feature sizes that mimic the dimensions of collagen fibrils (65–100 nm lines, 1:1–1:1.5 pitch). Further, these sub-100 nm lines acted as guides for migration of metastatic cancer cells. Interestingly, even at this subcellular scale, metastatic cell migration was abrogated when cells were forced to move perpendicular to these lines. Compared to flat surfaces, 65 nm lines enhanced the formation of actin stress fibers and filopodia of metastatic cells. This was accompanied by increased formation of focal contacts, visualized by immunofluorescent staining of phospho-focal adhesion kinase along the protruding lamellipodia. Simple lined nanotopography appears to be an informative platform for studying the physical cues of the ECM in a pseudo-3D format and likely mimics physical aspects of collagen fibrils. Metastatic cancer cells appear distinctively well adapted to sense these features using filopodia protrusions to enhance their alignment and migration.     

Wild Turkey (Meleagris gallopavo) association to roads: implications for distance sampling

Road-based distance sampling is a common technique used to estimate the density of many wildlife species but potential biases exist unless the target population is randomly distributed around roads. Our objective was to determine if and when Rio Grande wild turkeys (Meleagris gallopavo intermedia; RGWT) were randomly distributed around roads to identify time periods in which road-based surveys would be most appropriate. We used triangulated locations obtained from radiotelemetry of RGWTs in the Edwards Plateau (2001?C2003), Rolling Plains (2000?C2006), and South Texas (2003?C2006) ecoregions. Using a geographic information system, we conducted a use and availability analysis by sex, season, and time of day for each ecoregion to determine RGWT use of areas near roads (<200 m). We found the most appropriate time to conduct road-based distance sampling was from 1 December to 15 March during morning or afternoon. Our results suggested road-based surveys conducted during these periods should yield generally unbiased results in the Rolling Plains and Edwards Plateau ecoregions. We recommend researchers and managers investigate animal distributions around roads before implementing road-based monitoring programs for other wildlife species.     

Exosomal Lipids Impact Notch Signaling and Induce Death of Human Pancreatic Tumoral SOJ-6 Cells

Exosomes are of increasing interest as alternative mode of cell-to-cell communication. We previously reported that exosomes secreted by human SOJ-6 pancreatic tumor cells induce (glyco)protein ligand-independent cell death and inhibit Notch-1 pathway, this latter being particularly active during carcinogenesis and in cancer stem cells. Therefore, we asked whether exosomal lipids were key-elements for cell death and hypothesized that cholesterol-rich membrane microdomains were privileged sites of exosome interactions with tumor cells. To address these questions and based on the lipid composition of exosomes from SOJ-6 cells (Ristorcelli et al. (2008) FASEB J. 22; 3358–3369) enriched in cholesterol and sphingomyelin (lipids forming liquid-ordered phase, Lo) and depleted in phospholipids (lipids forming liquid-disordered phase, Ld), we designed Synthetic Exosome-Like Nanoparticles (SELN) with ratios Lo/Ld from 3.0 to 6.0 framing that of SOJ-6 cell exosomes. SELN decreased tumor cell survival, the higher the Lo/Ld ratio, the lower the cell survival. This decreased survival was due to activation of cell death with inhibition of Notch pathway. FRET analyses indicated fusions/exchanges of SELN with cell membranes. Fluorescent SELN co-localized with the ganglioside GM1 then with Rab5A, markers of lipid microdomains and of early endosomes, respectively. These interactions occurred at lipid microdomains of plasma and/or endosome membranes where the Notch-1 pathway matures. We thus demonstrated a major role for lipids in interactions between SELN and tumor cells, and in the ensued cell death. To our knowledge this is the first report on such effects of lipidic nanoparticles on tumor cell behavior. This may have implications in tumor progression.     

Parasites of fishes in the recently inundated ephemeral Lake Liambezi,Namibia

Lake Liambezi forms the periodic connection between the upper Zambezi, Kwando and Okavango rivers. A full parasitological assessment was conducted on 86 fish, representing 14 species in six families sampled in August 2011. Parasite diversity was low and dominated by species with complex life cycles involving intermediate hosts. Most prevalent were larval nematodes (Contracaecum sp.) infecting 12 and Trypanasoma sp. infecting nine of the 14 host species. The intra-erythrocytic parasite Babesiosoma mariae was found in the blood of Coptodon rendalli and Oreochromis andersonii with prevalence of 50% and 60%, respectively. The host-specific monogenean Annulotrema hepseti was recorded only from H. cuvieri with a prevalence of 100%. Notable absences were the copepod and branchiuran parasites that have direct lifecycles and usually occur in high prevalence and abundance in the region. Because parasites with direct life cycles can only be transported into the lake on the host fish, their absence suggests limited immigration of infected fishes into the lake. This suggests that internal recruitment dominates over immigration in the fish population dynamics in Lake Liambezi.     

Glycoengineering of alphaGal xenoantigen on recombinant peptide bearing the J28 pancreatic oncofetal glycotope

In human pancreatic adenocarcinoma, alterations of glycosylation processes leads to the expression of tumor-associated carbohydrate antigens, representing potential targets for cancer immunotherapy. Among these pancreatic tumor-associated carbohydrate antigens, the J28 glycotope located within the O-glycosylated mucin-like C-terminal domain of the fetoacinar pancreatic protein (FAPP) and expressed at the surface of human tumoral tissues, can be a good target for anticancer therapeutic vaccines. However, the oncodevelopmental self character of the J28 glycotope associated with the low immunogenicity of tumor-associated carbohydrate antigens may be a major obstacle to effective anti-tumor vaccine therapy. In this study, we have investigated a method to increase the immunogenicity of the recombinant pancreatic oncofetal J28 glycotope by glycoengineering Galalpha1,3Galss1,4GlcNAc-R (alphaGal epitope) which may be recognized by natural anti-alphaGal antibody present in humans. For this purpose, we have developed a stable Chinese hamster ovary cell clone expressing the alphaGal epitope by transfecting the cDNA encoding the alpha1,3galactosyltransferase. These cells have been previously equipped to produce the recombinant O-glycosylated C-terminal domain of FAPP carrying the J28 glycotope. As a consequence, the C-terminal domain of FAPP produced by these cells carries the alphaGal epitope on oligosaccharide structures associated with the J28 glycotope. Furthermore, we show that this recombinant "alpha1,3galactosyl and J28 glycotope" may not only be targeted by human natural anti-alphaGal antibodies but also by the mAbJ28, suggesting that the J28 glycotope remains accessible to the immune system as vaccinating agent. This approach may be used for many identified tumor-associated carbohydrate antigens which can be glycoengineered to carry a alphaGal epitope to increase their immunogenicity and to develop therapeutic vaccines.