Female‐borne cues affecting Psyttalia concolor (Hymenoptera: Braconidae) male behavior during courtship and mating

Knowledge of the mechanisms that regulate courtship and mating behavior in Psyttalia concolor (Szépligeti)–a koinobiont endophagous solitary parasitoid of the olive fruit fly, Bactrocera oleae (Rossi), and of other fruit flies–is essential to its mass rearing and management. Augmentative releases of P. concolor for olive fruit fly control started in the Mediterranean areas in the 1950s and still continue with limited success. We determined the influence of visual and chemical cues on courtship and mating behavior of this braconid and the possible effect of the mating status of males and females in the perception of these cues. Our results suggest that integration of visual and chemical stimuli are fundamental for mate location and courtship. Indeed, the optimal response of the male was achieved when physical and chemical cues were simultaneously presented and vision and olfaction worked synergistically.     

Quality of Visual Cue Affects Visual Reweighting in Quiet Standing

Sensory reweighting is a characteristic of postural control functioning adopted to accommodate environmental changes. The use of mono or binocular cues induces visual reduction/increment of moving room influences on postural sway, suggesting a visual reweighting due to the quality of available sensory cues. Because in our previous study visual conditions were set before each trial, participants could adjust the weight of the different sensory systems in an anticipatory manner based upon the reduction in quality of the visual information. Nevertheless, in daily situations this adjustment is a dynamical process and occurs during ongoing movement. The purpose of this study was to examine the effect of visual transitions in the coupling between visual information and body sway in two different distances from the front wall of a moving room. Eleven young adults stood upright inside of a moving room in two distances (75 and 150 cm) wearing a liquid crystal lenses goggles, which allow individual lenses transition from opaque to transparent and vice-versa. Participants stood still during five minutes for each trial and the lenses status changed every one minute (no vision to binocular vision, no vision to monocular vision, binocular vision to monocular vision, and vice-versa). Results showed that farther distance and monocular vision reduced the effect of visual manipulation on postural sway. The effect of visual transition was condition dependent, with a stronger effect when transitions involved binocular vision than monocular vision. Based upon these results, we conclude that the increased distance from the front wall of the room reduced the effect of visual manipulation on postural sway and that sensory reweighting is stimulus quality dependent, with binocular vision producing a much stronger down/up-weighting than monocular vision.     

HPV18 Utilizes Two Alternative Branch Sites for E6~*I Splicing to Produce E7 Protein

Human papillomavirus 18(HPV18) E6 and E7 oncogenes are transcribed as a single bicistronic E6 E7 pre-mRNA. The E6 ORF region in the bicistronic E6 E7 pre-mRNA contains an intron. Splicing of this intron disrupts the E6 ORF integrity and produces a spliced E6~*I RNA for efficient E7 translation. Here we report that the E6 intron has two overlapped branch point sequences(BPS) upstream of its 30 splice site, with an identical heptamer AACUA■C, for E6~*I splicing. One heptamer has a branch site adenosine(underlined) at nt 384 and the other at nt 388. E6~*I splicing efficiency correlates to the expression level of E6 and E7 proteins and depends on the selection of which branch site. In general, E6~*I splicing prefers the 30 ss-proximal branch site at nt 388 over the distal branch site at nt 384. Inactivation of the nt 388 branch site was found to activate a cryptic acceptor site at nt 636 for aberrant RNA splicing. Together, these data suggest that HPV18 modulates its production ratio of E6 and E7 proteins by alternative selection of the two mapped branch sites for the E6~*I splicing, which could be beneficial in its productive or oncogenic infection according to the host cell environment.     

Conformation-sensitive antibodies against alzheimer amyloid-beta by immunization with a thioredoxin-constrained B-cell epitope peptide

Immunotherapy against the amyloid-beta (Abeta) peptide is a valuable potential treatment for Alzheimer disease (AD). An ideal antigen should be soluble and nontoxic, avoid the C-terminally located T-cell epitope of Abeta, and yet be capable of eliciting antibodies that recognize Abeta fibrils and neurotoxic Abeta oligomers but not the physiological monomeric species of Abeta. We have described here the construction and immunological characterization of a recombinant antigen with these features obtained by tandem multimerization of the immunodominant B-cell epitope peptide Abeta1-15 (Abeta15) within the active site loop of bacterial thioredoxin (Trx). Chimeric Trx(Abeta15)n polypeptides bearing one, four, or eight copies of Abeta15 were constructed and injected into mice in combination with alum, an adjuvant approved for human use. All three polypeptides were found to be immunogenic, yet eliciting antibodies with distinct recognition specificities. The anti-Trx(Abeta15)4 antibody, in particular, recognized Abeta42 fibrils and oligomers but not monomers and exhibited the same kind of conformational selectivity against transthyretin, an amyloidogenic protein unrelated in sequence to Abeta. We have also demonstrated that anti-Trx(Abeta15)4, which binds to human AD plaques, markedly reduces Abeta pathology in transgenic AD mice. The data indicate that a conformational epitope shared by oligomers and fibrils can be mimicked by a thioredoxin-constrained Abeta fragment repeat and identify Trx(Abeta15)4 as a promising new tool for AD immunotherapy.     

Kunitz-type protease inhibitors group B from Solanum palustre

Five Kunitz protease inhibitor group B genes were isolated from the genome of the diploid non-tuber-forming potato species Solanum palustre. Three of five new genes share 99% identity to the published KPI-B genes from various cultivated potato accessions, while others exhibit 96% identity. Spls-KPI-B2 and Spls-KPI-B4 proteins contain unique substitutions of the most conserved residues usually involved to trypsin and chymotrypsin-specific binding sites of Kunitz-type protease inhibitor (KPI)-B, respectively. To test the inhibition of trypsin and chymotrypsin by Spls-KPI proteins, five of them were produced in E. coli purified using a Ni-sepharose resin and ion-exchange chromatography. All recombinant Spls-KPI-B inhibited trypsin; K(i) values ranged from 84.8 (Spls-KPI-B4), 345.5 (Spls-KPI-B1), and 1310.6 nM (Spls-KPI-B2) to 3883.5 (Spls-KPI-B5) and 8370 nM (Spls-KPI-B3). In addition, Spls-KPI-B1 and Spls-KPI-B4 inhibited chymotrypsin. These data suggest that regardless of substitutions of key active-center residues both Spls-KPI-B4 and Spls-KPI-B1 are functional trypsin-chymotrypsin inhibitors.     

The N-Myc down regulated Gene1 (NDRG1) Is a Rab4a effector involved in vesicular recycling of E-cadherin

Cell to cell adhesion is mediated by adhesion molecules present on the cell surface. Downregulation of molecules that form the adhesion complex is a characteristic of metastatic cancer cells. Downregulation of the N-myc down regulated gene1 (NDRG1) increases prostate and breast metastasis. The exact function of NDRG1 is not known. Here by using live cell confocal microscopy and in vitro reconstitution, we report that NDRG1 is involved in recycling the adhesion molecule E-cadherin thereby stabilizing it. Evidence is provided that NDRG1 recruits on recycling endosomes in the Trans Golgi network by binding to phosphotidylinositol 4-phosphate and interacts with membrane bound Rab4aGTPase. NDRG1 specifically interacts with constitutively active Rab4aQ67L mutant protein and not with GDP-bound Rab4aS22N mutant proving NDRG1 as a novel Rab4a effector. Transferrin recycling experiments reveals NDRG1 colocalizes with transferrin during the recycling phase. NDRG1 alters the kinetics of transferrin recycling in cells. NDRG1 knockdown cells show a delay in recycling transferrin, conversely NDRG1 overexpressing cells reveal an increase in rate of transferrin recycling. This novel finding of NDRG1 as a recycling protein involved with recycling of E-cadherin will aid in understanding NDRG1 role as a metastasis suppressor protein.     

Role of yeasts in the qualitative structuring of extra virgin olive oil

This review sought to describe the role played by some components of the microbiota of extra virgin olive oil (EVOO), particularly yeasts, in structuring the physicochemical and sensorial quality of freshly produced olive oil. Yeasts can survive during the entire storage period of the product. To date, approximately 25 yeast species isolated from oil produced in more than six countries have been identified, eight of which are classified as new species. Some yeast species improve the health qualities of oil, whereas many others improve the chemical composition and sensory characteristics based on β-glucosidase and esterase enzymes, which are involved in the hydrolysis of the bitter glucoside known as oleuropein. However, some species, which are typically favoured by the high water content in the oily matrix, such as lipase-producing yeasts, can worsen the initial chemical characteristics of EVOO oil during storage. Some physical treatments that are compatible with the EVOO production specification affect the biotic component of the oil by reducing the concentration of yeasts. The possibility of minimizing the invasive action on the biotic component of the oil by appropriately selecting the physical treatment for each oil is discussed.     

Associative learning in immature lacewings (Ceraeochrysa cubana)

It is known that many social insects and arthropod predators and parasitoids can learn the association between a resource and volatile cues. Although there are various studies on the effect of experience in immature arthropods on behavior later in adult life, not much is known about the effects of such experiences on immature behavior. This was investigated here in the lacewing Ceraeochrysa cubana (Hagen) (Neuroptera: Chrysopidae). Whereas adults of this lacewing feed on plant‐provided food and honeydew, larvae are voracious polyphagous predators of several insect pests, and therefore important for biological control. Hence, studying the foraging behavior and the effects of learning in immatures of this species is important. We exposed immatures to the volatile methyl salicylate (MeSA), which was either associated with food or with the absence of food. Subsequently, their response to this volatile was tested in an olfactometer. Immatures that had experienced the association of MeSA with food were attracted to it and immatures that were exposed to MeSA during food deprivation were repelled. Subsequently, predator immatures that had experienced the association between MeSA and food were released on a plant without food and were found to use this volatile in locating patches with food. In contrast, larvae without such experience were found equally on food patches with and without the volatile. We conclude that these immature predators are capable of learning the association between volatiles and food, or the absence of food, and use this during foraging.