Venomics of the ectoparasitoid wasp Bracon nigricans.

BACKGROUND: Venom is one of the most important sources of regulation factors used by parasitic Hymenoptera to redirect host physiology in favour of the developing offspring. This has stimulated a number of studies, both at functional and "omics" level, which, however, are still quite limited for ectophagous parasitoids that permanently paralyze and suppress their victims (i.e., idiobiont parasitoids). RESULTS: Here we present a combined transcriptomic and proteomic study of the venom of the generalist idiobiont wasp Bracon nigricans, an ectophagous larval parasitoid of different lepidopteran species, for which we recently described the host regulation strategy and the functional role of the venom in the induction of physiological changes in parasitized hosts. The experimental approach used led to the identification of the main components of B. nigricans venom involved in host regulation. Enzymes degrading lipids, proteins and carbohydrates are likely involved in the mobilization of storage nutrients from the fat body and may concurrently be responsible for the release of neurotoxic fatty acids inducing paralysis, and for the modulation of host immune responses. CONCLUSION: The present work contributes to fill the gap of knowledge on venom composition in ectoparasitoid wasps, and, along with our previous physiological study on this species, provides the foundation on which to develop a functional model of host regulation, based both on physiological and molecular data. This paves the way towards a better understanding of parasitism evolution in the basal lineages of Hymenoptera and to the possible exploitation of venom as source of bioinsecticidal molecules.

Identification of the main venom protein components of Aphidius ervi, a parasitoid wasp of the aphid model Acyrthosiphon pisum.

BACKGROUND: Endoparasitoid wasps are important natural enemies of the widely distributed aphid pests and are mainly used as biological control agents. However, despite the increased interest on aphid interaction networks, only sparse information is available on the factors used by parasitoids to modulate the aphid physiology. Our aim was here to identify the major protein components of the venom injected at oviposition by Aphidius ervi to ensure successful development in its aphid host, Acyrthosiphon pisum. RESULTS: A combined large-scale transcriptomic and proteomic approach allowed us to identify 16 putative venom proteins among which three γ-glutamyl transpeptidases (γ-GTs) were by far the most abundant. Two of the γ-GTs most likely correspond to alleles of the same gene, with one of these alleles previously described as involved in host castration. The third γ-GT was only distantly related to the others and may not be functional owing to the presence of mutations in the active site. Among the other abundant proteins in the venom, several were unique to A. ervi such as the molecular chaperone endoplasmin possibly involved in protecting proteins during their secretion and transport in the host. Abundant transcripts encoding three secreted cystein-rich toxin-like peptides whose function remains to be explored were also identified. CONCLUSIONS: Our data further support the role of γ-GTs as key players in A. ervi success on aphid hosts. However, they also evidence that this wasp venom is a complex fluid that contains diverse, more or less specific, protein components. Their characterization will undoubtedly help deciphering parasitoid-aphid and parasitoid-aphid-symbiont interactions. Finally, this study also shed light on the quick evolution of venom components through processes such as duplication and convergent recruitment of virulence factors between unrelated organisms.

Five-year results of arthroscopic techniques for the treatment of acetabular chondral lesions in femoroacetabular impingement.

PURPOSE: This study assesses and compares the clinical outcomes of the arthroscopic matrix-induced autologous chondrocyte implant (MACI) and autologous matrix-induced chondrogenesis (AMIC) techniques for the treatment of acetabular chondral defects between 2 and 4 cm(2) consequent to femoral acetabular impingement. METHODS: Fifty-seven consecutive patients were treated with the MACI (n = 26) or AMIC (n = 31) technique. Patients were assessed pre-operatively and up to five years using the modified Harris Hip Score (mHHS) to compare outcomes. RESULTS: In both the MACI and AMIC groups, significant hip score improvements were measured over baseline levels at six months post-op (81.2 ± 8.4 for MACI, 80.3 ± 8.3 for AMIC, both p < 0.001). The mHHS continued to improve up to three years post-op and remained stable over time until the final five year follow-up. Statistically significant differences between the groups were not observed. The mean mHHS improvement at the five year follow-up with respect to preoperative level was 37.8 ± 5.9 and 39.1 ± 5.9 in patients who underwent MACI and AMIC, respectively (NS). Subgroup analysis of both MACI and AMIC treatment outcomes for patients with an initial chondral defect larger than 3 cm(2) yielded comparable results at each time point. CONCLUSIONS: This study suggests that both arthroscopic MACI and AMIC are valid procedures to repair medium-sized chondral defects on the acetabular side of the hip found during treatment of femoroacetabular impingement. Due to its high sustainability and minimal invasiveness, the single-stage AMIC procedure can reduce total treatment time and minimise morbidity while providing the same beneficial effects as the two-stage MACI intervention.

A new embryonic pattern in parasitic wasps: divergence in early development may not be associated with lifestyle.

Comparative embryogenesis of Encarsia formosa and Encarsia pergandiella (Hymenoptera Aphelinidae), two endoparasitoids of whiteflies (Hemiptera Aleyrodidae), revealed two strongly diverging developmental patterns. Indeed, the centrolecithal anhydropic egg of E. formosa developed through a superficial cleavage, as it occurs in Nasonia vitripennis, Apis mellifera, and Drosophila melanogaster. In contrast, the alecithal hydropic egg of E. pergandiella developed through holoblastic cleavage within a specialized extra-embryonic membrane (EEM). Since this developmental pattern evolved independently in several lineages of hymenopteran endoparasitoids, departures from the superficial cleavage mode have been argued to be strongly canalized in response to a shift from ecto- to endoparasitic lifestyle. Coexistence of both developmental patterns in two congeneric species suggests that alterations of early embryonic development may not be correlated with lifestyle. In addition, embryogenesis of E. pergandiella exhibited the following developmental novelties compared to other species possessing a hydropic egg: (i) polar body derivatives early acquired a cytoskeletal boundary prior to any other cellularization event; (ii) cellularization was asynchronous, starting with an early differentiation of a single apical blastomere at the end of the third cleavage; (iii) appearance of cytoskeletal boundaries of embryo blastomeres occurred between the third and fourth cleavages; (iv) the EEM originated through asynchronous participation of three separate lineages of cleavage nuclei, one of which associated with the polar body derivatives in a syncytium. Our results confirm a scenario of high plasticity in the early developmental strategies of hymenopteran endoparasitoids.

To divide or not to divide: An alternative behavior for teratocytes in Encarsia pergandiella (Hymenoptera: Aphelinidae).

Encarsia pergandiella (Hymenoptera: Aphelinidae) is an endoparasitoid with an unusual embryonic development compared to most of congeneric species and all other members of the superfamily Chalcidoidea. The developmental background of this wasp is based on an alecithal hydropic egg, with the embryo developing inside an extra-embryonic membrane which dissociates at hatching into special larva-assisting cells, the teratocytes. In E. pergandiella many teratocytes at hatching were multinucleated syncytial cells with no evidence of a cellular membrane separating the nuclei. These teratocytes during larval development produced smaller uninucleated teratocytes, through successive divisions obtained by progressive ingrowth of the plasmatic membrane, accompanied by appearance of degeneration symptoms, such as protrusions and blebs. As a consequence of this divisional process teratocytes showed a size reduction and an increase in number of about four times during the second day of larval development. Only on the third day of larval life teratocytes started to decrease in number, until total disappearance at larval maturation. This behaviour is in striking contrast with all other studied systems in which teratocytes do not divide and progressively decrease in number as the parasitoid larva develops.

Hip osteochondral lesions: arthroscopic evaluation.

BACKGROUND: Hip arthroscopy has allowed the diagnosis and treatment of chondral injuries. METHODS: We retrospectively analysed the intraoperative data of 359 patients treated with hip arthroscopy from January 2012 to December 2013. We estimated the frequency, location and extension of acetabular cartilage (AC) injuries and their correlation to femoroacetabular impingement (FAI). RESULTS: Grade 1 and 2 acetabular chondral lesions were not statistically significant in incidence, location and extension. Chondral lesions were absent on the acetabulum in 3.9% of cases, significantly lower compared to the femoral head (32.0%). 101 (28.1%) were affected by an acetabular chondral lesion. In 244 (68.0%) the chondral lesion was located on both acetabulum and femoral head. On the acetabulum, peripheral superior and superior-posterior area were frequently involved. Grade 4 acetabular chondral defects showed a significant high location on the superior-anterior, superior and superior-posterior area, involving both the peripheral and central surface. Delamination was present in 113 (31.5%) patients. Patients affected by acetabular delamination showed a reduced injury extension if compared to grade 3 or 4. 81 patients (25%) revealed acetabular chondral lesions grade 2a, 3 and 4 without any radiological, clinical or arthroscopic sign of FAI. CONCLUSIONS: Location, extension and degree of hip chondral lesions show a progression toward a progressive degeneration. The high percentage of chondral delamination in the hip must be taken in consideration. The presence of symptomatic chondral lesion in cases with no radiological evidence of FAI, suggests that their aetiopathogenesis could be related to biomechanical alterations.