Agonosoma trilineatum (Heteroptera: Scutelleridae) a biological control agent of the weed bellyache bush,Jatropha gossypiifolia (Euphorbiaceae)

Bellyache bush, Jatropha gossypiifolia L., is a serious weed of northern Australia. Agonosoma trilineatum (F.) is an insect from tropical America released in Australia in 2003 as a biological control agent against bellyache bush. It feeds on seeds and has the potential to reduce seed production, thereby potentially reducing the rate of spread and recruitment. To test the host specificity of A. trilineatum, four biological responses to host plant species were determined: development of nymphs, oviposition preferences, adult feeding and frequency of mating. Development of nymphs to adults and adult feeding only occurred on three Jatropha spp. These species also supported mating and oogenesis but only J. gossypiifolia was accepted for oviposition. Mating did not occur in the presence of other plant species. The evidence indicates that there is little risk associated with the release of this insect species in Australia and probably other countries where this weed is a problem. The probability of this insect expanding its host range is low because multiple aspects of the biology would need to change simultaneously. A. trilineatum was released in Australia between 2003 and 2007. A Climex model indicated that coastal areas of Queensland and the Northern Territory would be climatically most suitable for this insect.     

Prioritising potential guilds of specialist herbivores as biological control agents for prickly acacia through simulated herbivory

Understanding plant response to herbivory facilitates the prioritisation of guilds of specialist herbivores as biological control agents based on their potential impacts. Prickly acacia ( Acacia nilotica ssp. indica ) is a weed of national significance in Australia and is a target for biological control. Information on the susceptibility of prickly acacia to herbivory is limited, and there is no information available on the plant organ (i.e. leaf, shoot and root in isolation or in combination) most susceptible to herbivory. We evaluated the ability of prickly acacia seedlings, to respond to different types of simulated herbivory (defoliation, shoot damage, root damage and combinations), at varying frequencies (no herbivory, single, two and three events of herbivory) to identify the type and frequency of herbivory that will be required to reduce the growth and vigour. Defoliation and shoot damage, individually, had a significant negative impact on prickly acacia seedlings. For the defoliation to be effective, more than two defoliation events were required, whereas a single bout of shoot damage was enough to cause a significant reduction in plant vigour. A combination of defoliation + shoot damage had the greatest negative impact. The study highlights the need to prioritise specialist leaf and shoot herbivores as potential biological control agents for prickly acacia.     

Ship Mediated Fish Invasions in Australia: Two New Introductions and A Consideration of Two Previous Invasions

Two species of fishes, the northwest Pacific Acentrogobius pflaumi (Bleeker 1853) (Perciformes: Gobiidae) and the New Zealand Forsterygion lapillum Hardy (1989) (Perciformes: Tripterygiidae), are newly reported as recent introductions in Port Phillip Bay, southeastern Australia. Forsterygion lapillum is restricted to a commercial port in the western area of the bay, while A. pflaumi occurs in all areas of the bay except the entrance. Both species are among the most abundant fishes collected in occupied habitats. It seems probable that they were introduced as eggs, larvae or juveniles in ships ballast water. While both A. pflaumi and F. lapillum appear to be well suited to conditions in Australia, populations of two previously introduced marine fishes (the gobiidsAcanthogobius flavimanus and Tridentiger trigonocephalus) have failed to rapidly expand their distributions and seem to be controlled by factors yet to be determined.     

Identification of neutrophil granule protein cathepsin G as a novel chemotactic agonist for the G protein-coupled formyl peptide receptor

The antimicrobial and proinflammatory neutrophil granule protein cathepsin G (CaG) has been reported as a chemoattractant for human phagocytic leukocytes by using a putative G protein coupled receptor. In an effort to identify potential CaG receptor(s), we found that CaG-induced phagocyte migration was specifically attenuated by the bacterial chemotactic peptide fMLP, suggesting these two chemoattractants might share a receptor. In fact, CaG chemoattracts rat basophilic leukemia cells (RBL cells) expressing the high affinity human fMLP receptor FPR, but not parental RBL cells or cells transfected with other chemoattractant receptors. In addition, a specific FPR Ab and a defined FPR antagonist, cyclosporin H, abolished the chemotactic response of phagocytes and FPR-transfected cells to CaG. Furthermore, CaG down-regulated the cell surface expression of FPR in association with receptor internalization. Unlike fMLP, CaG did not induce potent Ca(2+) flux and was a relatively weaker activator of MAPKs through FPR. Yet CaG activated an atypical protein kinase C isozyme, protein kinase Czeta, which was essential for FPR to mediate the chemotactic activity of CaG. Thus, our studies identify CaG as a novel, host-derived chemotactic agonist for FPR and expand the functional scope of this receptor in inflammatory and immune responses.     

An ancestral Ashkenazi haplotype at the HMPS/CRAC1 locus on 15q13-q14 is associated with hereditary mixed polyposis syndrome

The putative locus for hereditary mixed polyposis syndrome (HMPS) in a large family of Ashkenazi descent (SM96) was previously reported to map to chromosome sub-bands 6q16-q21. However, new clinical data, together with molecular data from additional family members, have shown 6q linkage to be incorrect. A high-density genomewide screen for the HMPS gene was therefore performed on SM96, using stringent criteria for assignment of affection status to minimize phenocopy rates. Significant evidence of linkage was found only on a region on chromosome 15q13-q14. Since this region encompassed CRAC1, a locus involved in inherited susceptibility to colorectal adenomas and carcinomas in another Ashkenazi family (SM1311), we determined whether HMPS and CRAC1 might be the same. We found that affected individuals from both families shared a haplotype between D15S1031 and D15S118; the haplotype was rare in the general Ashkenazi population. A third informative family, SM2952, showed linkage of disease to HMPS/CRAC1 and shared the putative ancestral haplotype, as did a further two families, SMU and RF. Although there are probably multiple causes of the multiple colorectal adenoma and cancer phenotype in Ashkenazim, an important one is the HMPS/CRAC1 locus on 15q13-q14.     

Kinetic and molecular analysis of nuclear export factor CRM1 association with its cargo in vivo

The nucleocytoplasmic transport receptor CRM1 mediates the export of macromolecules from the nucleus to the cytoplasm by forming a ternary complex with a cargo molecule and RanGTP. The in vivo mechanism of CRM1 export complex formation and its mobility throughout the nucleus have not been fully elucidated. More information is required to fully understand complex formation and the dynamics of CRM1-cargo-RanGTP complexes in space and time. We demonstrate true molecular interaction of CRM1 with its Rev cargo in living cells by using fluorescence resonance energy transfer (FRET). Interestingly, we found that the inhibitory effect of leptomycin B on this CRM1-cargo interaction is Ran dependent. Using fluorescence recovery after photobleaching (FRAP), we show that CRM1 moves at rates similar to that of free green fluorescent protein in the nucleoplasm. A slower mobility was detected on the nuclear membrane, consistent with known CRM1 interactions with nuclear pores. Based on these data, we propose an in vivo model in which CRM1 roams through the nucleus in search of high-affinity binding sites. CRM1 is able to bind Rev cargo in the nucleolus, and upon RanGTP binding a functional export complex is produced that is exported to the cytoplasm.     

Quantification of epithelial cells in coculture with fibroblasts by fluorescence image analysis

BACKGROUND: To demonstrate that senescent fibroblasts stimulate the proliferation and neoplastic transformation of premalignant epithelial cells (Krtolica et al.: Proc Natl Acad Sci USA 98:12072-12077, 2001), we developed methods to quantify the proliferation of epithelial cells cocultured with fibroblasts. METHODS: We stained epithelial-fibroblast cocultures with the fluorescent DNA-intercalating dye 4,6-diamidino-2-phenylindole (DAPI), or expressed green fluorescent protein (GFP) in the epithelial cells, and then cultured them with fibroblasts. The cocultures were photographed under an inverted microscope with appropriate filters, and the fluorescent images were captured with a digital camera. We modified an image analysis program to selectively recognize the smaller, more intensely fluorescent epithelial cell nuclei in DAPI-stained cultures and used the program to quantify areas with DAPI fluorescence generated by epithelial nuclei or GFP fluorescence generated by epithelial cells in each field. RESULTS: Analysis of the image areas with DAPI and GFP fluorescences produced nearly identical quantification of epithelial cells in coculture with fibroblasts. We confirmed these results by manual counting. In addition, GFP labeling permitted kinetic studies of the same coculture over multiple time points. CONCLUSIONS: The image analysis-based quantification method we describe here is an easy and reliable way to monitor cells in coculture and should be useful for a variety of cell biological studies.