VITPOR AI, A Coagulation Factor XIIa Inhibitor from Porphyra yezoensis: In Vivo Mode of Action and Assessment of Platelet Function Analysis.

BACKGROUND: Thrombosis represents as the prime contributor to the burden of diseases, worldwide. Conventional anticoagulants for thrombosis therapy have a common bleeding side effect. Bioactive peptides are studied to be an effective alternative for currently available therapeutic drugs. OBJECTIVE: In this study, VITPOR AI peptide, a previously reported coagulation FXIIa inhibitor from Nori (Porphyra yezoensis), was assessed for its inhibitory activity against FXIIa and its in vivo mode of action. METHODS: In vivo efficacy as well as the antithrombotic property of the peptide was evaluated in mice model by ex vivo activated Partial Thromboplastin Time assay, tail transection model and whole blood clotting time. The enzyme kinetics was studied using chromogenic substrate assay. RESULTS: The kinetic behaviour of VITPOR AI showed that the peptide is a competitive inhibitor of FXIIa. Peptide showed significant inhibition of platelet adhesion and aggregation. VITPOR AI exhibited significant antithrombotic activity. Furthermore, ex vivo activated Partial Thromboplastin Time assay revealed that VITPOR AI exhibited potent anticoagulant activity in vivo. Tail bleeding assay revealed that the peptide did not prolong bleeding time in mice even at a higher dose of 5 mg/kg. Cytotoxicity studies of the peptide against human blood leukocytes indicated the safety of the peptide. CONCLUSION: VITPOR AI could be prospected as a potent anticoagulant with Factor XIIa inhibition, antiplatelet aggregation and antithrombotic activity. It was also studied to have no bleeding side effect.

Dynamics of δ(15)N isotopic signatures of different intertidal macroalgal species: Assessment of bioindicators of N sources in coastal areas.

δ(15)N of annual (Ulva sp., Porphyra sp.) and perennial intertidal seaweed species (Chondrus crispus, Fucus sp.) collected on 17 sampling points along the French coast of the English Channel in 2012 and 2013 were assessed on their suitability as bioindicators of N pollution in coastal areas. A sine function applied for δ(15)N time series data showed for all the species the same seasonal trend with lowest δ(15)N values in April and highest in summer but with no significant interspecific differences of amplitude (α) and phase angle (ϕ). This model provides a useful tool for monitoring the inter-annual changes of N pollution. An interspecific variability of δ(15)N values was observed, probably due to their tolerance to emersion. An in vitro study for comparing the kinetic acquisition of the isotopic signal and N uptake mechanisms of each species underlined the influence of algal physiology on the δ(15)N interspecific variability.

Construction of a dense genetic linkage map and mapping quantitative trait loci for economic traits of a doubled haploid population of Pyropia haitanensis (Bangiales, Rhodophyta).

BACKGROUND: Pyropia haitanensis is one of the most economically important mariculture crops in China. A high-density genetic map has not been published yet and quantitative trait locus (QTL) mapping has not been undertaken for P. haitanensis because of a lack of sufficient molecular markers. Specific length amplified fragment sequencing (SLAF-seq) was developed recently for large-scale, high resolution de novo marker discovery and genotyping. In this study, SLAF-seq was used to obtain mass length polymorphic markers to construct a high-density genetic map for P. haitanensis. RESULTS: In total, 120.33 Gb of data containing 75.21 M pair-end reads was obtained after sequencing. The average coverage for each SLAF marker was 75.50-fold in the male parent, 74.02-fold in the female parent, and 6.14-fold average in each double haploid individual. In total, 188,982 SLAFs were detected, of which 6731 were length polymorphic SLAFs that could be used to construct a genetic map. The final map included 4550 length polymorphic markers that were combined into 740 bins on five linkage groups, with a length of 874.33 cM and an average distance of 1.18 cM between adjacent bins. This map was used for QTL mapping to identify chromosomal regions associated with six economically important traits: frond length, width, thickness, fresh weight, growth rates of frond length and growth rates of fresh weight. Fifteen QTLs were identified for these traits. The value of phenotypic variance explained by an individual QTL ranged from 9.59 to 16.61 %, and the confidence interval of each QTL ranged from 0.97 cM to 16.51 cM. CONCLUSIONS: The first high-density genetic linkage map for P. haitanensis was constructed, and fifteen QTLs associated with six economically important traits were identified. The results of this study not only provide a platform for gene and QTL fine mapping, map-based gene isolation, and molecular breeding for P. haitanensis, but will also serve as a reference for positioning sequence scaffolds on a physical map and will assist in the process of assembling the P. haitanensis genome sequence. This will have a positive impact on breeding programs that aim to increase the production and quality of P. haitanensis in the future.