Plant cystatins

Plant cystatins have been the object of intense research since the publication of a first paper reporting their existence more than 20 years ago. These ubiquitous inhibitors of Cys proteases play several important roles in plants, from the control of various physiological and cellular processes in planta to the inhibition of exogenous Cys proteases secreted by herbivorous arthropods and pathogens to digest or colonize plant tissues. After an overview of current knowledge about the evolution, structure and inhibitory mechanism of plant cystatins, we review the different roles attributed to these proteins in plants. The potential of recombinant plant cystatins as effective pesticidal proteins in crop protection is also considered, as well as protein engineering approaches adopted over the years to improve their inhibitory potency and specificity towards Cys proteases of biotechnological interest.     

Immune fingerprinting through repertoire similarity

Immune repertoires provide a unique fingerprint reflecting the immune history of individuals, with potential applications in precision medicine. However, the question of how personal that information is and how it can be used to identify individuals has not been explored. Here, we show that individuals can be uniquely identified from repertoires of just a few thousands lymphocytes. We present “Immprint,” a classifier using an information-theoretic measure of repertoire similarity to distinguish pairs of repertoire samples coming from the same versus different individuals. Using published T-cell receptor repertoires and statistical modeling, we tested its ability to identify individuals with great accuracy, including identical twins, by computing false positive and false negative rates < 10⁻⁶ from samples composed of 10,000 T-cells. We verified through longitudinal datasets that the method is robust to acute infections and that the immune fingerprint is stable for at least three years. These results emphasize the private and personal nature of repertoire data.     

Bioremediation potential and lead removal capacity of heavy metal-tolerant yeasts isolated from Dayet Oum Ghellaz Lake water (northwest of Algeria)

International Microbiology - Seven metal-resistant yeast strains were isolated and selected from Dayet Oum Ghellaz Lake water (northwest of Algeria) known as a highly polluted area by lead and...     

Contrasting effects of peroxisome-proliferator-activated receptor (PPAR)γ agonists on membrane-associated prostaglandin E2 synthase-1 in IL-1β-stimulated rat chondrocytes: evidence for PPARγ-independent inhibition by 15-deoxy-Δ12,14prostaglandin J2

Microsomal prostaglandin E synthase (mPGES)-1 is a newly identified inducible enzyme of the arachidonic acid cascade with a key function in prostaglandin (PG)E₂ synthesis. We investigated the kinetics of inducible cyclo-oxygenase (COX)-2 and mPGES-1 expression with respect to the production of 6-keto-PGF_1α and PGE₂ in rat chondrocytes stimulated with 10 ng/ml IL-1β, and compared their modulation by peroxisome-proliferator-activated receptor (PPAR)γ agonists. Real-time PCR analysis showed that IL-1β induced COX-2 expression maximally (37-fold) at 12 hours and mPGES-1 expression maximally (68-fold) at 24 hours. Levels of 6-keto-PGF_1α and PGE₂ peaked 24 hours after stimulation with IL-1β; the induction of PGE₂ was greater (11-fold versus 70-fold, respectively). The cyclopentenone 15-deoxy-Δ^12,14prostaglandin J₂ (15d-PGJ₂) decreased prostaglandin synthesis in a dose-dependent manner (0.1 to 10 μM), with more potency on PGE₂ level than on 6-keto-PGF_1α level (-90% versus -66% at 10 μM). A high dose of 15d-PGJ₂ partly decreased COX-2 expression but decreased mPGES-1 expression almost completely at both the mRNA and protein levels. Rosiglitazone was poorly effective on these parameters even at 10 μM. Inhibitory effects of 10 μM 15d-PGJ₂ were neither reduced by PPARγ blockade with GW-9662 nor enhanced by PPARγ overexpression, supporting a PPARγ-independent mechanism. EMSA and TransAM^? analyses demonstrated that mutated IκBα almost completely suppressed the stimulating effect of IL-1β on mPGES-1 expression and PGE₂ production, whereas 15d-PGJ₂ inhibited NF-κB transactivation. These data demonstrate the following in IL-1-stimulated rat chondrocytes: first, mPGES-1 is rate limiting for PGE₂ synthesis; second, activation of the prostaglandin cascade requires NF-κB activation; third, 15d-PGJ₂ strongly inhibits the synthesis of prostaglandins, in contrast with rosiglitazone; fourth, inhibition by 15d-PGJ₂ occurs independently of PPARγ through inhibition of the NF-κB pathway; fifth, mPGES-1 is the main target of 15d-PGJ₂.     

Physiological and biochemical effects of Olea europaea leaf extracts from four phenological growth stages on the oogenesis of female locust Locusta migratoria

The effects of olive leaf extract (OLE) are studied on several reproductive variables and the ovarian biochemical composition of Locusta migratoria (Orthoptera: Acrididae) adult females. The methanolic extracts are prepared from the leaves sampled during four phenological growth stages of olive tree: cluster formation (Cf), swelling inflorescence buds (Sib), full flowering (Ff) and endocarp hardening (Eh). When applied to adult females during the pre‐ovipositional phase, the treatment elicites a significant adverse effect on their reproductive potential. Indeed, OLE significantly reduces both fecundity and fertility and affects oocyte growth during the first gonadotrophic cycle, as indicated by measurements of ovarian weight, length of terminal oocytes and ovarian index. Furthermore, OLE is examined with respect to ovarian biochemical components. Biochemical analyses reveal a significant reduction of ovarian contents of proteins, lipids and carbohydrates, suggesting a disruption in the incorporation of the haemolymph metabolites in the oocytes and an interference of OLE with the vitellogenesis process. The antigonadotrophic effect is confirmed by a histological study of the ovaries, which clearly shows a delay in ovarian development and in yolk accumulation in the basal oocytes of treated females. The most effect is noted with the extract prepared from the leaves collected at the swelling inflorescence buds for all measured parameters, which appears to be related to its high content of polyphenols.