Peptidases of Trichobilharzia regenti (Schistosomatidae) and its molluscan host Radix peregra S. Lat. (Lymnaeidae): construction and screening of cDNA library from intramolluscan stages of the parasite

Trichobilharzia regenti is a neurotropic bird schistosome,causing cercarial dermatitis in humans. In this study, ZAP cDNA expression library from Radix peregra s. lat. hepatopancreases containing intramolluscan stages of T. regenti was constructed and screened using PCR with specific and degenerate primers, designed according to previously described serine and cysteine peptidases of other parasite species. Full-length sequences of cathepsins B1 and L, and two serine peptidases, named RpSP1 and RpSP2, were obtained.The protein-protein BLAST analysis and parallel control reactions with template from hepatopancreases of T. regenti non-infected snails revealed that only cathepsin B1 was of parasite origin. The remaining sequences were derived from the snail intermediate host, which implies that the initial source of parasite mRNA was contaminated by snail tissue.Regardless of this contamination, the cDNA library remains an excellent molecular tool for detection and identification of bioactive molecules in T. regenti cercariae.     

Osteomalacia as a result of phosphorus deficiency in beef cattle grazing subtropical native pastures in Uruguay

We investigated 2 outbreaks of osteomalacia as a result of phosphorus (P) deficiency in herds of lactating beef cows grazing subtropical native pastures in Uruguay. Cows exhibited pica, difficulty to stand and walk, rib fractures, and body weight loss even with adequate forage availability. Osteopenia and severe osteomalacia were observed on gross and histologic examination. The concentrations of bicarbonate-extractable P in soil (4.0, 4.1 mg P/kg), total P in pasture (0.9, 1.1 g P/kg), inorganic P in serum (1.0, 0.71 mmol P/L), and P in bone (73 mg P/mL) were all low. Although injectable and mineral salt supplements provided additional P in both outbreaks, these supplementary amounts were insufficient to prevent P deficiency. The P ingested by the cows from the pasture and supplements would have provided 20–55% of their daily P requirements of ~21 g P/d. Osteomalacia occurred in cattle at the 2 ranches as a result of severe P deficiency in the soil and forage, and inadequate P supplementation. Following diagnosis, control of P deficiency in beef cattle requires estimation of the amount of pasture P ingested and provision of sufficient additional supplementary P to meet the animals’ requirements.     

Agroforestry systems recover tree carbon stock faster than natural succession in Eastern Amazon,Brazil

Agroforestry Systems - The potential of agroforestry systems (AFS) for atmospheric carbon sequestration in degraded tropical lands is of key interest for climate change and rural development...     

Abundance and richness of invertebrates in shade-grown versus sun-exposed coffee home gardens in Indonesia

Agroforestry Systems - Complex agroforestry systems are suggested as a possible solution to reduce the effects of deforestation in the tropics while enhancing the livelihoods of local human...     

Enhancing Pinus pinea cone production by grafting in a non-native habitat

New Forests - Pinus pinea is an interesting species for its valued pine nuts. Despite the high demand for this nut, the species is mostly harvested from natural forests, because the time elapsed...     

Global genotype by environment trends in growth traits for Eucalyptus dunnii

New Forests - Eucalyptus dunnii Maiden (Dunn’s white gum) is a fast-growing tall tree with a restricted natural distribution in south-east Australia and favorable wood properties for pulp...     

Structure of genetic variation in vegetative phenology of Cedrela odorata L.: implications for tree breeding

New Forests - The study of vegetative phenology is important to understand adaptation to different environments and potential trade-offs with growth traits. Crown leaf-out and leaf-fall phenology...     

Resistance to amitraz in the parasitic honey bee mite Varroa destructor is associated with mutations in the β-adrenergic-like octopamine receptor

Varroa destructor is considered a major reason for high loss rate of Western honey bee (Apis mellifera) colonies. To prevent colony losses caused by V. destructor, it is necessary to actively manage the mite population. Beekeepers, particularly commercial beekeepers, have few alternative treatments other than synthetic acaricides to control the parasite, resulting in intensive treatment regimens that led to the evolution of resistance in mite populations. To investigate the mechanism of the resistance to amitraz detected in V. destructor mites from French and U.S. apiaries, we identified and characterized octopamine and tyramine receptors (the known targets of amitraz) in this species. The comparison of sequences obtained from mites collected from different apiaries with different treatment regimens, showed that the amino acid substitutions N87S or Y215H in the OctβR were associated with treatment failures reported in French or U.S. apiaries, respectively. Based on our findings, we have developed and tested two high throughput diagnostic assays based on TaqMan technology able to accurately detect mites carrying the mutations in this receptor. This valuable information may be of help for beekeepers when selecting the most suitable acaricide to manage V. destructor.

     

Basis and monitoring of methoxyfenozide resistance in the South American tomato pinworm Tuta absoluta

The South American tomato pinworm, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), is heavily targeted by insecticide applications. Methoxyfenozide is highly effective against T. absoluta with reduced side effects to natural enemies. This work aimed to (1) genetically and biochemically characterize resistance of the T. absoluta GBN population to methoxyfenozide, (2) establish cross resistance profiles with other insecticide groups and (3) monitor resistance in populations with the goal of improving T. absoluta insecticide resistance management (IRM). Methoxyfenozide resistance was completely recessive, polyfactorial and autosomal. Effective dominance revealed that 10 mg methoxyfenozide/L would be enough to eliminate susceptible homozygotes and heterozygotes, thus used to diagnose resistance in field populations. The synergism of methoxyfenozide toxicity in the resistant population for PBO (SR?=?95×), DEF (SR?=?51×) and DEM (SR?=?45×), suggested monooxygenases, esterases and glutathione S-transferases as resistance mechanisms. However, only monooxygenase activity appeared to be involved in methoxyfenozide resistance. Resistance ratio for methoxyfenozide (2352-fold) after selection and cross-resistance ratios of a lab-selected GBN strain (“GBN-Sel”) were significant relative to a susceptible strain “JDR1-Sus” for tebufenozide (656-fold), cartap hydrochloride (10.68-fold), deltamethrin (4.70-fold), abamectin (2.65-fold), lufenuron (2.22-fold) and indoxacarb (1.92-fold), with negative cross-resistance to spinetoram (0.32-fold). Evidence of control failures was observed in 10 field populations of T. absoluta (mortalities between 13 and 76%), and all populations showed frequencies of resistant phenotypes (percentage survivorship ranging between 4 and 96%). A rational basis for managing resistance to bisacylhydrazines is discussed, along with details of recommended T. absoluta resistance management tactics.