Distribution,dispersal and spread of the invasive social wasp (Vespula germanica) in Argentina

We studied the distribution and spread of the invasive social wasp Vespula germanica in Argentina, focusing on the contribution of queen dispersal to territorial expansion. Vespula germanica is native to Eurasia and has invaded several regions of the world, including Southern Argentina. Flight potential of field‐collected queens was measured using flight mills. Also, by means of an extensive survey we estimated the rate of spread by analysing the relationship between years since arrival and distance from the introduction locality. The mean distance flown by wasp queens in flight mills was 404.7 ± 140.8 m (mean ± SE, n = 59), while the rate of spread of V. germanica was estimated at 37.2 ± 2.1 km year^?1 (mean ± SE, n = 67), although faster towards the south. The observed spread rate of V. germanica wasps in Argentina confirms the invasive potential shown by several Hymenoptera species worldwide. Still, a stratified geographical expansion pattern does not match observed queen dispersal abilities, suggesting that human‐aided transport of hibernating queens is the central driver of the current distribution of these wasps. We suggest that despite several life‐history traits known for social insects that contribute to successful invasion, wasp spread must still rely strongly on human mediated pathways. This observation sheds light on those factors that are crucial for managing invasions of this and related pestiferous wasps.     

Cell Localization and Redistribution of the 67 kD Laminin Receptor and α6βl Integrin Subunits in Response to Laminin Stimulation: An Immunogold Electron Microscopy Study

The 67 kDa laminin receptor (67LR), one of several cell surface laminin-binding proteins, is involved in the interactions between cancer cells and laminin during tumor invasion and metastasis. A 37 kDa polypeptide (37LRP), previously identified as the 67LR precursor, is abundantly present in the cytoplasm and has been implicated in polysome formation. To better understand the cellular localization of the 67LR and its precursor, transmission electron microscopic studies of human melanoma A2058 cells were carried out using immunogold labeling and a variety of antibodies: (a) affinity purified antibodies directed against 37LRP cDNA-derived synthetic peptides; (b) anti-67LR monoclonal antibodies raised against intact human small cell lung carcinoma cells; and (c) monoclonal antibodies against the subunits of the integrin laminin receptor, α6β1. Double-labeling immunocyto-chemistry revealed that anti-67LR monoclonal antibodies as well as anti-37 LRP antibodies recognized antigens that were localized in the cytoplasm in electron dense structures. As expected, cell membrane labeling was also observed. Surprisingly, α6 and β1 integrin subunits were detected in the same cytoplasmic structures positive for the 67LR and the 37LRP. After addition of soluble laminin to A2058 cells in suspension, the number of labeled cytoplasmic structures increased especially in the vicinity of the plasma membrane, and were exported onto the cell surface. Neither fibronectin nor BSA induced such an effect. The data demonstrate that the 67 LR and the 37 LRP antibodies detect colocalized antigens that are in cytoplasmic structures with α6β1 integrin. These laminin binding protein rich structures could potentially form a supply of receptors that are exported to the surface upon exposure of the cells to laminin, with a consequent increase in the number of binding sites for the ligand. This system could define a mechanism through which cancer cells modulate their interaction with laminin.     

Targeting multiple tyrosine kinase receptors with Dovitinib blocks invasion and the interaction between tumor cells and cancer-associated fibroblasts in breast cancer

A constitutive and dynamic interaction between tumor cells and their surrounding stroma is a prerequisite for tumor invasion and metastasis. Fibroblasts and myofibroblasts (collectively called cancer associated fibroblasts, CAFs) often represent the major cellular components of tumor stroma. Tumor cells secret different growth factors which induce CAFs proliferation and differentiation, and, consequently, CAFs secrete different chemokines, cytokines or growth factors which induce tumor cell invasion and metastasis. In this study we showed here that CAFs from breast cancer surgical specimens significantly induced the invasion of breast cancer cells in vitro. Most interestingly, the novel multiple tyrosine kinase inhibitor Dovitinib significantly blocked the CAFs-induced invasion of breast cancer cells by, at least in part, inhibition of the expression and secretion of CCL2, CCL5 and VEGF in CAFs. Inhibition of PI3K/Akt/mTOR signaling could be responsible for the effects of Dovitinib, since Dovitinib antagonized the promoted phosphorylated Akt after treatment with PDGF, FGF or breast cancer cell-conditioned media. Treatment with Dovitinib in combination with PI3K/Akt/mTOR signaling inhibitors Ly294002 or RAD001 resulted in additive inhibition of cell invasion. This is the first in vitro study to show that the multiple tyrosine kinase inhibitor has therapeutic activities against breast cancer metastasis by targeting both tumor cells and CAFs.     

Species-specific impact of introduced largemouth bass Micropterus salmoides in the Groot Marico Freshwater Ecosystem Priority Area,South Africa

Largemouth bass Micropterus salmoides are among the world's 100 worst invaders and negatively affect aquatic biodiversity in many regions worldwide. In South Africa there is a paucity of empirical studies describing their impacts. The impact of M. salmoides on the fish community in the Groot Marico River catchment, an otherwise near-pristine river ecosystem and a freshwater ecosystem priority area, was assessed from surveys conducted in 2012. Fish presence and abundance were enumerated using multiple survey techniques, and their association with key habitat variables and the presence or absence of M. salmoides were assessed. A total of 14 native fish species were recorded, besides introduced M. salmoides, which occupied the majority of the mainstem and several tributaries downstream of barriers to upstream movement. Canonical correspondence analysis showed that only one native species, the Marico barb Barbus motebensis, had a negative spatial association with M. salmoides. Assessment of relative distributions showed this species to be excluded from M. salmoides-invaded river reaches, whereas the other native species were not visibly affected by the invader. This species-specificity of the impact of M. salmoides indicates that their impacts in South African streams may be dependent on predator-naiveté of prey.     

Scavenging behaviour and size-dependent carcass consumption of the black bullhead (Ameiurus melas)

This study examined the size-dependent scavenging behaviour of black bullheads Ameiurus melas under laboratory conditions, using common bleak Alburnus alburnus and pumpkinseed Lepomis gibbosus carcasses. Video camera observations showed that the activity of A. melas was higher at night, but substantial daytime activity was also recorded. Larger A. melas were more active than their smaller conspecifics, especially at night. All size classes exhibited a well-defined sequence of consuming different parts of the carcasses independent of size, but larger individuals tended to consume carcasses more efficiently. Carcasses of the softer-bodied A. alburnus were consumed more readily than those of the bonier L. gibbosus, independent of size. This scavenging behaviour of A. melas might facilitate the invasion success of the species.     

Establishment,spread, and impact of an invasive planthopper on its invasive host plant: Prokelisia marginata (Homoptera: Delphacidae) exploiting Spartina anglica (Poales: Poaceae) in Britain

1. Since its recent arrival in Britain, the planthopper Prokelisia marginata has spread widely around saltmarshes on the east and south coast of England and south Wales, feeding on Common Cordgrass, Spartina anglica, itself an invasive non-native species. 2. Results suggest that P. marginata populations in Britain benefit from a degree of natural enemy release. No evidence of parasitism was found in over 71 000 eggs, nymphs, and adults inspected. The only potential natural enemy control was suggested by a positive correlation between the densities of planthoppers and generalist spiders. 3. Experimental exposure under both glasshouse and field conditions to typical field densities of planthoppers resulted in significant negative effects on a number of host plant performance metrics. 4. Spartina anglica is important for stabilising estuarine sediments and has been deliberately planted for this purpose in the past. Its weakening as a result of heavy planthopper herbivory could have serious consequences for the long-term stability of Britain's vulnerable saltmarsh habitats.     

ARPC4 promotes bladder cancer cell invasion and is associated with lymph node metastasis

The significance of actin-related protein 2/3 complex subunit 4 (ARPC4) expression in bladder cancer, and its potential role in the invasion and migration of bladder cancer cells, has yet to be determined. This study was to identify the correlation between ARPC4 and lymph node metastasis, and to determine the role of ARPC4 in the invasive migration of T24 bladder cancer cells. One hundred and ninety-eight bladder cancer tissues and 40 normal bladder and lymph node tissues were examined. Tissue microarrays were constructed and subjected to immunohistochemical stating for ARPC4. Multiple logistic analysis was used to determine risk factors associated with bladder cancer metastasis. ARPC4 expression in T24 bladder cancer cells was suppressed using small interfering RNA and changes in protein levels were determined by Western blot analysis. The proliferation of bladder cancer cells after knocking down of ARPC4 was determined by cell counting kit-8. The effects of ARPC4 knockdown on T24 cell invasion and migration was determined using transwell and wound healing assays. Immunofluorescence analysis was performed to examine changes in pseudopodia formation and actin cytoskeleton structure. The expression of ARPC4 was elevated in bladder cancer tissues than normal tissues (84.3% vs 27.5%, P < 0.001). The multivariate logistic analysis demonstrated that the level of ARPC4, as a risk factor, was correlated with lymphatic metastasis (P < 0.05). ARPC4 knockdown attenuated proliferation, migration, invasion, and pseudopodia formation in T24 cells. ARPC4 expression, as a risk factor, is associated with lymphatic metastasis and is upregulated in bladder cancer tissues in comparison with normal tissues. Inhibition of ARPC4 expression significantly attenuates the proliferation, migration, and invasion of bladder cancer cell, possibly due to defects in pseudopodia formation.     

ROR2 promotes the epithelial-mesenchymal transition by regulating MAPK/p38 signaling pathway in breast cancer

Receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a tyrosine-protein kinase receptor highly implicated in the growth plate and cartilage development, which may be involved in epithelial-mesenchymal transition (EMT) in breast cancer (BC) cells. Although ROR2 is known to promote the migration of BC cells, the detailed mechanism of this event is still not clear. Here, we found that ROR2 expression was significantly increased in BC lymphatic metastatic tissue as well as BC samples compared to normal adjacent breast tissues. A higher expression of ROR2 in MDA-MB-231 and a lower expression of ROR2 in MCF-7 cells were observed. MDA-MB-231-siROR2 cells with ROR2 knockdown inhibited MDA-MB-231 cell invasion, migration, and clonal formation, while MCF-7-OvROR2 cells with overexpression showed the opposite results. The underlying mechanisms involved in ROR2-induced EMT in MDA-MB-231 and MCF-7 cells were further investigated. ROR2 may activate EMT progression in BC cells by altering MAPK kinase 3/6 (MKK3/6) expression. The expressions of transforming growth factor-β, matrix metalloproteinase-2 (MMP-2), and MMP-9, which were related to tumor cell invasion activities, were notably increased in MCF-7-OvROR2 cells. The EMT markers, including snail, N-cadherin, tissue inhibitor of metalloproteinases-1, and vimentin, were significantly upregulated in MCF-7-OvROR2 cells. On the contrary, E-cadherin was obviously reduced expressed in MCF-7-OvROR2 cells. ROR2 may regulate the malignant phenotype of BC cells possibly via activation of mitogen-activated protein kinase (MAPK)/p38 signaling pathway. Collectively, ROR2 promotes BC carcinogenesis by mediating the MAPK/p38 pathway, which is independent of Wnt5α.