Production of mosquitoes in rainwater tanks and wells on Yorke Island, Torres Strait: Preliminary study

The Torres Strait in northernmost Queensland, Australia, is subject to periodic outbreaks of dengue. A large outbreak of dengue 2 in 1996-97 affected five islands, resulting in 200 confirmed cases. On most of the affected islands, rainwater tanks were a common breeding site for vector mosquitoes. Rainwater tanks, wells and household containers filled with water are the most common breeding sites for dengue mosquitoes (Aedes aegypti), the primary vector of dengue in Queensland. We report on surveys conducted in February 2002 to measure the productivity of rainwater tanks and wells on Yorke Is. (Torres Strait), the first time the productivity of rainwater tanks has been measured in Australia. Of 60 rainwater tanks sampled, 10 had broken screens. Using a sticky emergence trap, 179 adult mosquitoes were collected, consisting of 63 Aedes scutellaris and 116 Culex quinquefasciatus. One unscreened tank produced 177 (99%) of the adults. A plankton net was used to sample 16 wells; 12 positive wells yielded 111 immature (larvae and pupae) mosquitoes, consisting of 57% and 43% Ae. scutellaris and Cx. quinquefasciatus, respectively. The apparent displacement of Ae. aegypti by Ae. scutellaris is discussed. Measures to reduce the likelihood of future dengue outbreaks are recommended.

Spatial distribution of vectors of Ross River virus and Barmah Forest virus on Russell Island, Moreton Bay, Queensland

We used a network of 20 carbon dioxide- and octenol-supplemented light traps to sample adult mosquitoes throughout Russell Island in southern Moreton Bay, south-east Queensland. Between February and April 2001, an estimated 1365 564 adult female mosquitoes were collected. In contrast to an average catch of 9754 female mosquitoes per trap night on Russell Island, reference traps set on Macleay Island and on the mainland returned average catches of 3172 and 222, respectively. On Russell Island, Ochlerotatus vigilax (Skuse), Coquillettidia linealis (Skuse), Culex annulirostris Skuse and Verrallina funerea (Theobald), known or suspected vectors of Ross River (RR) and/or Barmah Forest (BF) viruses, comprised 89.6% of the 25 taxa collected. When the spatial distributions of the above species were mapped and analysed using local spatial statistics, all were found to be present in highest numbers towards the southern end of the island during most of the 7 weeks. This indicated the presence of more suitable adult harbourage sites and/or suboptimal larval control efficacy. As immature stages and the breeding habitat of Cq. linealis are as yet undescribed, this species in particular presents a considerable impediment to proposed development scenarios. The method presented here of mapping the numbers of mosquitoes throughout a local government area allows specific areas that have high vector numbers to be defined.

The interaction of water flow and nutrients on aquatic plant growth

A long-term experiment was conducted to compare the effects of flowing and still water on growth, and the relationship between water flow and nutrients, in Aponogeton elongatus, a submerged aquatic macrophyte. A. elongatus plants were grown for 23 weeks with three levels of nutrition (0, 0.5 and 1g Osmocote Plus(R) fertiliser pot(-1)) in aquaria containing stirred or unstirred water. Fertilized plants grew much better than non-fertilized. The highest fertilizer level produced 29% wider leaves and 58% higher total dry weight in stirred water. Stirred water increased leaf area by 40% and tuber size by 81%, but only with the highest level of nutrition. These results suggest that this plant depends on its roots for mineral uptake, rather than from the open water, and the major limitation to growth in still water is the supply of dissolved inorganic carbon. It was the combined effects of nutrient availability and stirring that produced the strongest response in plant growth, morphology and composition. This study provides some explanation for the observations of others that these plants grow best in creeks or river systems with permanently flowing water.

Stock discrimination and movements of narrow-barred Spanish mackerel across northern Australia as indicated by parasites

The parasite fauna of Spanish mackerel Scomberomorus commerson from 10 sites across northern Australia and one site in Indonesia, was examined to evaluate the degree of movement and subsequent stock structure of the fish. Kupang fish (Indonesia) had very few Terranova spp.. Grillotia branchi, Otobothrium cysticum or Pterobothrium sp. compared to Australian fish, indicating that no Australian fish enter the Kupang fishery. Univariate and discriminant function analysis of four 'temporary' parasite species, the copepod Pseudocyenoides armatus and the monogeneans Gotocotyla bivaginalis, Pricea multae and Pseudothoracocotyla ovalis, demonstrated little similarity between areas of northern Australia, indicating minimal short-term exchange between neighbouring groups of S. commerson. Analyses of five 'permanent' parasite species, the larval helminths G. branchi, O. cysticum, Pterobothrium sp., Callitetrarhynchus gracilis and Paranybelinia balli, also revealed large differences between areas thus indicating long-term separation. There are at least six parasitological stocks across northern Australia: Fog Bay/Bathurst Island, Cape Wessel. Groote/Sir Edward Pellew. Mornington Island, Weipa. and the Torres Strait. The occurrence of a few irregular fish in the samples suggested that LIP to 5% of fish moved between stocks during their lifetime. The similarity of within-school variability to that between schools showed that the fish do not form long-term school associations. (C) 2003 The Fisheries Society of the British Isles.

Movements of the ricefield rat, Rattus argentiventer, near a trap-barrier system in rice crops in West Java, Indonesia

The movements of the ricefield rats (Rattus argentiventer) near a trap-barrier system (TBS) were assessed in lowland flood-irrigated rice crops in West Java, Indonesia, to test the hypothesis that a TBS with a 'trap-crop' modifies the movements of rats within 200 m from the trap-crop. The home range use and locations of rat burrows were assessed using radiotelemetry at two sites, one with a TBS with trap-crop (Treatment site, the crop inside the fence was planted 3 weeks earlier than the surrounding crop) and the other with a TBS without trap-crop (Control site, the crop inside the fence was planted at the same time as the surrounding crop). Each TBS was a 50 x 50 m plastic fence with eight multiple-capture rat traps set at the base. More than 700 rats were caught in the TBS with trap-crop, whereas only 10 rats were caught in the TBS without trap-crop. The home range size of females was significantly smaller at the Treatment site (0.96 ha) than the Control site (2.99 ha), but there was no difference for males. Seventy-eight per cent of rats caught in the TBS and fitted with radiocollars had their daytime burrow locations within 200 m of the TBS. We could not determine if the rats caught in the TBS were residents or transients according to demographic parameters. Our results support the hypothesis that a TBS with a trap-crop protects the surrounding rice crop out to a distance of at least 200 m.

Growth hormone receptor and insulin-like growth factor-I immunoreactivity in osteoclast-like cells during tooth eruption in the toothless (Osteopetrotic) rat following treatment with colony-stimulating factor-1

In the toothless (tl/tl) osteopetrotic rat, teeth form but fail to erupt. Treatment of tl/tl rats with colony-stimulating factor-1 (CSF-1) activates bone resorption by osteoclasts, permits tooth eruption, and up-regulates the immunoreactivity of bone marrow mononuclear cells to growth hormone receptor (GHr) and insulin-like growth factor (IGF)-I. This study examined the distribution of tartrate-resistant acid phosphatase (TRAP) and immunoreactivity for GHr and IGF-I in osteoclast-like cells located on the alveolar bone margin, adjacent to the lower first molar crown, in 14-day-old normal and tl/tl rats, following treatment with CSF-1. Osteoclast-like cells demonstrated a positive reaction for TRAP, GHr, and IGF-I in all groups. However, in tl/tl tissue, osteoclast-like cells were generally negative for GHr. There was no significant difference in the total number of TRAP, GHr, and IGF-I-positive osteoclast-like cells on the adjacent bone margin in normal, normal treated with CSF-1, and tl/tl rats. CSF-1 treatment of the tl/tl rat significantly increased the total number of osteoclast-like cells, which were positive for TRAP (p < 0.001), GHr (p < 0.05) and IGF-I (P < 0.01).

Field evaluation of a sentinel mosquito (Diptera : culicidae) trap system to detect Japanese encephalitis in remote Australia

Incursions of Japanese encephalitis (JE) virus into northern Queensland are currently monitored using sentinel pigs. However, the maintenance of these pigs is expensive, and because pigs are the major amplifying hosts of the virus, they may contribute to JE transmission. Therefore, we evaluated a mosquito-based detection system to potentially replace the sentinel pigs. Single, inactivated JE-infected Culex annulirostris Skuse and C. sitiens Wiedemann were placed into pools of uninfected mosquitoes that were housed in a Mosquito Magnet Pro (MM) trap set under wet season field conditions in Cairns, Queensland for 0, 7, or 14 d. JE viral RNA was detected (cycling threshold [CT] = 40) in 11/ 12, 10/14, and 2/5 pools containing 200, 1,000, and 5,000 mosquitoes, respectively, using a TaqMan real-time reverse transcription-polymerase chain reaction (RT-PCR). The ability to detect virus was not affected by the length of time pools were maintained under field conditions, although the CT score tended to increase with field exposure time. Furthermore, JE viral RNA was detected in three pools of 1,000 mosquitoes collected from Badu Island using a MM trap. These results indicated that a mosquito trap system employing self-powered traps, such as the MosquitoMagnet, and a real-time PCR system, could be used to monitor for JE in remote areas.

Mosquito host-feeding patterns and implications for Japanese encephalitis virus transmission in northern Australia and Papua New Guinea

Japanese encephalitis (JE) virus spread to northern Australia during the 1990s, transmitted by Culex annulirostris Skuse and other mosquitoes (Diptera: Culicidae). To determine the relative importance of various hosts for potential vectors of JE virus, we investigated the host-feeding patterns of mosquitoes in northern Australia and Western Province of Papua New Guinea, with particular attention to pigs, Sus scrofa L. - the main amplifying host of JE virus in South-east Asia. Mosquitoes were collected by CDC light traps baited with dry ice and 1-octen-3-ol, run 16.00-08.00 hours, mostly set away from human habitations, if possible in places frequented by feral pigs. Bloodmeals of 2569 mosquitoes, representing 15 species, were identified by gel diffusion assay. All species had fed mostly on mammals: only 30%) were trapped where domestic pigs were kept close to human habitation. From seven of eight locations on the Australian mainland, the majority of Cx. annulirostris had obtained their bloodmeals from marsupials, probably the Agile wallaby Macropus agilis (Gould). Overall proportions of mosquito bloodmeals identified as marsupial were 60% from the Gulf Plains region of Australia, 78% from the Cape York Peninsula and 64% from the Daru area of Papua New Guinea. Thus, despite the abundance of feral pigs in northern Australia, our findings suggest that marsupials divert host-seeking Cx. annulirostris away from pigs. As marsupials are poor JE virus hosts, the prevalence of marsupials may impede the establishment of JE virus in Australia.

Characterization of E-cadherin endocytosis in isolated MCF-7 and Chinese hamster ovary cells - The initial fate of unbound E-cadherin

The endocytosis of E-cadherin has recently emerged as an important determinant of cadherin function with the potential to participate in remodeling adhesive contacts. In this study we focused on the initial fate of E-cadherin when it predominantly exists free on the cell surface prior to adhesive binding or incorporation into junctions. Surface-labeling techniques were used to define the endocytic itinerary of E-cadherin in MCF-7 cells and in Chinese hamster ovary cells stably expressing human E-cadherin. We found that in this experimental system E-cadherin entered a transferrin-negative compartment before transport to the early endosomal compartment, where it merged with classical clathrin-mediated uptake pathways. E-cadherin endocytosis was inhibited by mutant dynamin, but not by an Eps15 mutant that effectively blocked transferrin internalization. Furthermore, sustained signaling by the ARF6 GTPase appeared to trap endocytosed E-cadherin in large peripheral structures. We conclude that in isolated cells unbound E-cadherin on the cell surface is predominantly endocytosed by a clathrin-independent pathway resembling macropinocytotic internalization, which then fuses with the early endosomal system. Taken with earlier reports, this suggests the possibility that multiple pathways exist for E-cadherin entry into cells that are likely to reflect cell context and regulation.

Impact of commercial fishing on Trindade Island and Martin Vaz Archipelago, Brazil : characteristics, conservation status of the species involved and prospects for preservation

Reportamos atividades de pesca comerciais no complexo insular mais afastado da costa brasileira: Ilha da Trindade e Arquipélago Martin Vaz. As atividades foram estudadas através de embarques e entrevistas com os mestres e pescadores das embarcações durante uma expedição cientifica realizada entre fevereiro e abril de 2007. Quatro modalidades de atividades de pesca são realizadas na região, capturando ao menos sete espécies que possuem algum risco de extinção. O estabelecimento de normas específicas de restrição para atividades que pescam sobre os recifes das ilhas é uma alternativa para a conservação das espécies ameaçadas. O monitoramento das embarcações pode ocorrer via satélite através do programa nacional de rastreamento de embarcações pesqueiras (PREPS).

Variação na dieta da tartaruga verde, Chelonia mydas, e o impacto da ingestão de lixo ao longo da costa brasileira

Neste trabalho nós estudamos a dieta da tartaruga verde, Chelonia mydas, e os fatores envolvidos na variação de sua ecologia alimentar. Avaliamos também o impacto da ingestão de lixo, e os fatores que podem explicar a elevada ingestão destes resíduos entre os animais marinhos. No estudo da ecologia alimentar, nós avaliamos mais de 400 indivíduos, entre dados originais e da literatura, distribuídos ao longo de um gradiente latitudinal e diversos ambientes. As tartarugas se alimentaram majoritariamente de macroalgas, porém apresentaram uma grande plasticidade alimentar, tanto em relação à estratégia de forrageamento quanto à dieta. Nas regiões mais frias e com menor disponibilidade de algas, as tartarugas mudaram de uma dieta herbívora, para uma dieta baseada em matéria animal. Esta mudança de dieta acarretou também em uma mudança de estratégia de forrageamento, saindo da alimentação bentônica para uma alimentação pelágica. Estratégia esta que também foi encontrada nas áreas estuarinas. A plasticidade alimentar se deve à interação de fatores intrínsecos (restrições fisiológicas) e extrínsecos (regionais e locais). As diferenças nas estratégias de forragenamento acarretam também em diferenças na exposição a ameaças. Um exemplo disso é a ingestão de lixo, que apesar de ter sido registrada em mais de 70% das tartarugas (N = 265), representou uma ameaça maior aos animais com estratégia de forrageamento pelágica. O plástico foi o material mais ingerido, tendo como principal fonte itens relacionados à alimentação e sacolas plásticas. O estudo também mostrou que uma quantidade pequena de lixo (0,5 g) é suficiente para causar a morte. Este resultado revelou que o potencial de letalidade por ingestão de lixo é muito maior que a mortalidade observada. A verdadeira ameaça da ingestão de lixo está sendo mascarada pela elevada mortalidade relacionada às atividades pesqueiras. A ingestão de lixo é normalmente atribuída à confusão de um item alimentar específico com o resíduo, como águas-vivas e sacolas plásticas. Porém, nós mostramos que se trata de uma questão mais ampla, e usamos a tartaruga verde, aves marinhas e peixes para ressaltar a importância de outros fatores como: abundância do lixo no ambiente, estratégia de forrageamento, capacidade de detecção do resíduo e amplitude da dieta. Nós acreditamos que a ingestão de lixo ocorre devido a uma armadilha evolutiva muito mais ampla do que a previamente sugerida, e que deve afetar muito mais espécies que as que foram até hoje reportadas. Desarmar esta armadilha será particularmente difícil devido ao contínuo e crescente despejo de plástico no ambiente marinho e sua alta persistência no ambiente.

Production of cabbage grown in pots containing legumes' root and shoot

Roots effect is not generally considered in studies assessing the performance of crops in response to green manuring. However, such effect can contribute to a better understanding of crop rotation. The aim of this study was to assess the effect of root and shoot of two legumes on the production of cabbage. The experiment was conducted in pots of 10 liters containing substrate of 2:1 soil/sand. The experiment was arranged in a factorial scheme (2x3 + 2) in a randomized block design with five replicates using two legume species (Crotalaria juncea L. and Canavalia ensiformis L), three plant parts (root, shoot, or whole plant), and two additional treatments (mineral fertilization with 100% and 50% of the recommended dose of N for growing cabbage). Pots with legume treatments received mineral fertilizer with 50% of the recommended dose of N for growing cabbage. The experimental plot consisted of a pot containing one plant of cabbage. Legumes were grown in pots and harvested at 78 days. The root biomass was determined in extra pots. Production was assessed using head fresh and dry weight. The application of the whole plant of both legume species reduced cabbage production. However, root or shoot of both legume species was equivalent to 50% of mineral N fertilization required for the cultivation of cabbage.

Silicate fertilizer and irrigation depth in corn production

Calcium-magnesium silicates improve the soil physicochemical properties and provide benefits to plant nutrition, since they are sources of silica, calcium and magnesium. The objective of this study was to evaluate the grain yield of irrigated corn fertilized with calcium-magnesium silicate. The experiment was carried out in a greenhouse in Campina Grande - PB, Brazil, using plastic pots containing 80 kg of soil. The treatments consisted of the combination of four irrigation depths, related to water replacement of 50, 75, 100 and 125% of the crop evapotranspiration, with fertilizer levels of 0, 82, 164 and 246 g of calcium-magnesium silicate, with three replications. The experimental design was in randomized blocks, with the irrigation depths distributed in bands while the silicon levels constituted the subplots. Corn yield was influenced by calcium-magnesium silicate and by irrigation depth, obtaining the greatest grain yield with the dose of 164 g pot-1 irrigated at the highest water level. The water-use efficiency of in corn production tended to decrease when the irrigation depth was increased. The best water-use efficiency was observed when the irrigation level was between 87 and 174 mm, and the dose of silicate was 164 g pot-1.

Juvenile tree growth correlates with photosynthesis and leaf phosphorus content in central Amazonia

Light and soil water availability may limit carbon uptake of trees in tropical rainforests. The objective of this work was to determine how photosynthetic traits of juvenile trees respond to variations in rainfall seasonality, leaf nutrient content, and opening of the forest canopy. The correlation between leaf nutrient content and annual growth rate of saplings was also assessed. In a terra firme rainforest of the central Amazon, leaf nutrient content and gas exchange parameters were measured in five sapling tree species in the dry and rainy season of 2008. Sapling growth was measured in 2008 and 2009. Rainfall seasonality led to variations in soil water content, but it did not affect leaf gas exchange parameters. Subtle changes in the canopy opening affected CO2 saturated photosynthesis (A pot, p = 0.04). Although A pot was affected by leaf nutrient content (as follows: P > Mg > Ca > N > K), the relative growth rate of saplings correlated solely with leaf P content (r = 0.52, p = 0.003). At present, reduction in soil water content during the dry season does not seem to be strong enough to cause any effect on photosynthesis of saplings in central Amazonia. This study shows that leaf P content is positively correlated with sapling growth in the central Amazon. Therefore, the positive effect of atmospheric CO2 fertilization on long-term tree growth will depend on the ability of trees to absorb additional amount of P