Major Depletion of Plasmacytoid Dendritic Cells in HIV-2 Infection,an Attenuated Form of HIV Disease

Plasmacytoid dendritic cells (pDC) provide an important link between innate and acquired immunity, mediating their action mainly through IFN-α production. pDC suppress HIV-1 replication, but there is increasing evidence suggesting they may also contribute to the increased levels of cell apoptosis and pan-immune activation associated with disease progression. Although having the same clinical spectrum, HIV-2 infection is characterized by a strikingly lower viremia and a much slower rate of CD4 decline and AIDS progression than HIV-1, irrespective of disease stage. We report here a similar marked reduction in circulating pDC levels in untreated HIV-1 and HIV-2 infections in association with CD4 depletion and T cell activation, in spite of the undetectable viremia found in the majority of HIV-2 patients. Moreover, the same overexpression of CD86 and PD-L1 on circulating pDC was found in both infections irrespective of disease stage or viremia status. Our observation that pDC depletion occurs in HIV-2 infected patients with undetectable viremia indicates that mechanisms other than direct viral infection determine the pDC depletion during persistent infections. However, viremia was associated with an impairment of IFN-α production on a per pDC basis upon TLR9 stimulation. These data support the possibility that diminished function in vitro may relate to prior activation by HIV virions in vivo, in agreement with our finding of higher expression levels of the IFN-α inducible gene, MxA, in HIV-1 than in HIV-2 individuals. Importantly, serum IFN-α levels were not elevated in HIV-2 infected individuals. In conclusion, our data in this unique natural model of “attenuated” HIV immunodeficiency contribute to the understanding of pDC biology in HIV/AIDS pathogenesis, showing that in the absence of detectable viremia a major depletion of circulating pDC in association with a relatively preserved IFN-α production does occur.     

Residues of thiamethoxam, aldicarb and its metabolites in coffee leaves and effect on the control of Leucoptera coffeella (Guérin-Mèneville) (Lepidoptera: Lyonetiidae)

The coffee leaf miner Leucoptera coffeella (Guérin-Mèneville), one of the major pests of coffee crops in Brazil, is mainly controlled with insecticides. The objective of this study was to evaluate the residues and the translocation of the insecticide thiamethoxam in coffee leaves, as well as to study its effect on the coffee leaf miner control, comparing it with aldicarb, used as standard. One experiment was set up in the county of Gar?a, SP from December/2001 to August/2002. The treatments used were: aldicarb 150 G at the rates of 2.25 and 4.50 g a.i./pit, thiamethoxam 10 GR, at the rates of 0.15 and 0.30 g a.i./pit and check. Twig samples were collected prior to and 30 , 60, 90, 120, 150, 180, 210 and 240 days after the application, at three coffee plant heights (lower, middle and upper third), and the percentage of mined leaves was evaluated. The determination of aldicarb residues, including their sulphoxide and sulfone metabolites and of thiamethoxam were performed by gas chromatography with a nitrogen-phosphorus and mass spectrometer detectors, respectively. The results indicated a uniform translocation of both insecticides in all three thirds of the coffee plants when applied to the soil. A higher persistence of thiamethoxam was verified with its residues being found for as far long as eight months following the application, while aldicarb residues, including the sulphoxide and sulfone metabolites, were found only until four to six months after the application. Control of the coffee leaf miner was observed with both insecticides.     

Effect of calcineurin inhibitors on myotoxic activity of crotoxin and Bothrops asper phospholipase A2 myotoxins in vivo and in vitro

Previous studies have shown that calcineurin activity plays a critical role in the myotoxic activity induced by crotoxin (CTX), a group II phospholipase A(2) (PLA(2)) with neurotoxic and myotoxic actions. In order to address whether calcineurin is also important for the activity of non-neurotoxic group II PLA(2) myotoxins we have compared the effects of calcineurin inhibition on the myotoxic capacity of CTX and the non-neurotoxic PLA(2)s, myotoxin II (Mt II) and myotoxin III (Mt III) from Bothrops asper venom. Rats were treated with cyclosporin A (CsA) or FK506, calcineurin inhibitors, and received an intramuscular injection of either CTX, Mt II or Mt III into the tibialis anterior. Animals were killed 24 h after injection of toxins. Tibialis anterior was removed and stored in liquid nitrogen. Myofibers in culture were also treated with CsA or FK506 and exposed to CTX, Mt II and Mt III. It was observed that, in contrast to CTX, CsA and FK506 do not attenuate myotoxic effects induced by both Mt II and Mt III in vivo and in vitro. The results of the present study suggest that calcineurin is not essential for the myotoxic activity of Mt II and Mt III, indicating that distinct intracellular pathways might be involved in myonecrosis induced by neurotoxic CTX and non-neurotoxic Bothrops sp. PLA(2) myotoxins. Alternatively, calcineurin dependent fast fiber type shift might render the muscle resistant to the action of CTX, without affecting its susceptibility to Bothrops sp. myotoxins.     

What’s for dinner? Assessing the value of an edible invasive species and outreach actions to promote its consumption

Biological Invasions - The consumption of edible aquatic invasive species has gained popularity as a means to minimize their impacts while easing pressure on native resources and ecosystems....     

Distribution of Bactrocera oleae (Rossi, 1790) throughout the Iberian Peninsula based on a maximum entropy modelling approach

The Iberian Peninsula (Portugal and Spain) is a great production area of olives. The fruit production can be severely affected by the olive fruit fly, Bactrocera oleae (Rossi, 1790) (Diptera). Detailed geographical distribution maps of key pests, such as B. oleae, are essential for their integrated management. Although different sources reporting the occurrence of B. oleae are available for sub-regions of Portugal and Spain, the data available are dispersed and centralisation of this information considering the Iberian Peninsula as a faunistic geographical unit is currently lacking. In this work, we built two distribution maps of B. oleae throughout the Iberian Peninsula, one based on occurrence sites and another based on its bioclimatic habitat suitability. After modelling the bioclimatic suitability of B. oleae using a maximum entropy model, three potential distribution areas beyond the previously known occurrence range of the olive fruit fly were identified corresponding to the autonomous community of Galicia (Spain), the Spanish and Portuguese sides of the International Douro Natural Park, and the autonomous community of Castilla y León (Spain). Interestingly, each region houses nowadays autochthonous olive cultivars. The drivers that most contributed to the model were the precipitation of the coldest quarter and the precipitation of driest month which agrees with the B. oleae bioecology. Although our approach is not fully-comprehensive in terms of occurrence sites, we show how a maxent modelling approach can be useful to identify potential risk areas of B. oleae occurrence throughout a target geographical extent such as the Iberian Peninsula.     

Coastal upwelling supplies oxygen-depleted water to the Columbia River estuary

Low dissolved oxygen (DO) is a common feature of many estuarine and shallow-water environments, and is often attributed to anthropogenic nutrient enrichment from terrestrial-fluvial pathways. However, recent events in the U.S. Pacific Northwest have highlighted that wind-forced upwelling can cause naturally occurring low DO water to move onto the continental shelf, leading to mortalities of benthic fish and invertebrates. Coastal estuaries in the Pacific Northwest are strongly linked to ocean forcings, and here we report observations on the spatial and temporal patterns of oxygen concentration in the Columbia River estuary. Hydrographic measurements were made from transect (spatial survey) or anchor station (temporal survey) deployments over a variety of wind stresses and tidal states during the upwelling seasons of 2006 through 2008. During this period, biologically stressful levels of dissolved oxygen were observed to enter the Columbia River estuary from oceanic sources, with minimum values close to the hypoxic threshold of 2.0 mg L(-1). Riverine water was consistently normoxic. Upwelling wind stress controlled the timing and magnitude of low DO events, while tidal-modulated estuarine circulation patterns influenced the spatial extent and duration of exposure to low DO water. Strong upwelling during neap tides produced the largest impact on the estuary. The observed oxygen concentrations likely had deleterious behavioral and physiological consequences for migrating juvenile salmon and benthic crabs. Based on a wind-forced supply mechanism, low DO events are probably common to the Columbia River and other regional estuaries and if conditions on the shelf deteriorate further, as observations and models predict, Pacific Northwest estuarine habitats could experience a decrease in environmental quality.     

A contribution to the diagnosis of Capillaria hepatica infection by indirect immunofluorescence test

A highly specific pattern of immunofluorescence was noted when sera from Capillaria hepatica-infected rats were tested against the homologous worms and eggs present either in paraffin or cryostat sections from mouse liver. The pattern was represented by a combined apple green fluorescence of the internal contents of worms and eggs, which persisted in serum-dilutions of 1:400 up to 1:1600. Unequivocal fluorescent pattern was observed from 15 days up to 3 months following inoculation of rats with embryonated C. hepatica eggs and such result was confirmed by the ELISA. After the 4th month of infection, the indirect immunofluorescence test turned negative, probably revealing the extinction of parasitism, however the ELISA was contradictory, disclosing high levels of antibodies in this period. The IIF was also negative when control normal rat sera and sera from rats administered by gavage with immature C. hepatica eggs (spurious infection), or for reactions made against Schistosoma mansoni eggs, although a weakly positive pattern occurred with Fasciola hepatica eggs. The indirect immunofluorescence test may be recommended for use with human sera to detect early C. hepatica infection in special clinical instances and in epidemiological surveys, since it is a simple, inexpensive, and reliable test, presenting excellent sensitivity and specificity. Although the diagnosis is positive only during early infection, this is the period when the symptoms are usually more severe and the need for differential diagnosis is greater.     

Mitochondrial gene order is not conserved in arthropods: prostriate and metastriate tick mitochondrial genomes

The entire mitochondrial genome was sequenced in a prostriate tick, Ixodes hexagonus, and a metastriate tick, Rhipicephalus sanguineus. Both genomes encode 22 tRNAs, 13 proteins, and two ribosomal RNAs. Prostriate ticks are basal members of Ixodidae and have the same gene order as Limulus polyphemus. In contrast, in R. sanguineus, a block of genes encoding NADH dehydrogenase subunit 1 (ND1), tRNA(Leu)(UUR), tRNA(Leu)(CUN), 16S rDNA, tRNA(Val), 12S rDNA, the control region, and the tRNA(Ile) and tRNA(Gln) have translocated to a position between the tRNA(Glu) and tRNA(Phe) genes. The tRNA(Cys) gene has translocated between the control region and the tRNA(Met) gene, and the tRNA(Leu)(CUN) gene has translocated between the tRNA(Ser)(UCN) gene and the control region. Furthermore, the control region is duplicated, and both copies undergo concerted evolution. Primers that flank these rearrangements confirm that this gene order is conserved in all metastriate ticks examined. Correspondence analysis of amino acid and codon use in the two ticks and in nine other arthropod mitochondrial genomes indicate a strong bias in R. sanguineus towards amino acids encoded by AT-rich codons.      

Competition or inhibition? Developmental strategies in the establishment of peripheral projections by leech neurons

Leech neurons, like those of other invertebrates and those of vertebrates, undergo specific interactions during development which serve to define their adult morphologies and synaptic connections. We review here several observations and experiments that illustrate these interactions. In particular, we consider how they shape and constrain peripheral arborizations and whether the evidence favors competition or inhibition as their mode of action.