Niosomes encapsulated in biohydrogels for tunable delivery of phytoalexin resveratrol
A series of biohydrogels based on mixtures of kappa-carrageenan (κ-carrageenan, κ-C) and gelatin were evaluated as potential soft delivery vehicles for the encapsulation and subsequent release of non-ionic surfactant vesicles (niosomes) loaded with resveratrol (RSV). The niosomes were prepared using a mixture of amphiphilic lipids Tween 80 and Span 80 in water. The results showed that RSV-niosomes did not significantly affect the hydrogelation properties of the biopolymer mixture. Moreover, in vitro drug release experiments from biohydrogels containing RSV-niosomes were successfully carried out under simulated gastrointestinal conditions. The RSV-niosomal liberation profiles from hydrogels were fitted using first order kinetics, Higuchi, Korsmeyer-Peppas and Weibull drug release models, showing the prevalence of diffusion mechanisms in each case. In addition, the RSV release was easily tuned by adjusting the total concentration of κ-C : gelatin. Interestingly, the niosomal-hydrogel system was also found to prevent the trans-to-cis photoisomerization of RSV.
Do mosses really exhibit so large distribution ranges? Insights from the integrative taxonomic study of the Lewinskya affinis complex (Orthotrichaceae, Bryopsida)
The strikingly lower number of bryophyte species, and in particular of endemic species, and their larger distribution ranges in comparison with angiosperms, have traditionally been interpreted in terms of their low diversification rates associated with a high long-distance dispersal capacity. This hypothesis is tested here with Lewinskya affinis (≡ Orthotrichum affine), a moss species widely spread across Europe, North and East Africa, southwestern Asia, and western North America. We tested competing taxonomic hypotheses derived from separate and combined analyses of multilocus sequence data, morphological characters, and geographical distributions. The best hypothesis, selected by a Bayes factor molecular delimitation analysis, established that L. affinis is a complex of no less than seven distinct species, including L. affinis s.str., L. fastigiata and L. leptocarpa, which were previously reduced into synonymy with L. affinis, and four new species. Discriminant analyses indicated that each of the seven species within L. affinis s.l. can be morphologically identified with a minimal error rate. None of these species exhibit a trans-oceanic range, suggesting that the broad distributions typically exhibited by moss species largely result from a taxonomic artefact. The presence of three sibling western North American species on the one hand, and four Old World sibling species on the other, suggests that there is a tendency for within-continent diversification rather than recurrent dispersal following speciation. The faster rate of diversification as compared to intercontinental migration reported here is in sharp contrast with earlier views of bryophyte species with wide ranges and low speciation rates.
First report of postmortem pH evolution and rigor mortis in guinea pigs
In the Andean region, Philippines, and central Africa most guinea pigs are raised for meat production. Guinea pig meat is of increasing interest to researchers. One of the critical questions in meat production is to know when muscles convert to meat. The objective of this study was to describe the pH evolution in guinea pig muscles and to determine the establishment and resolution time of rigor mortis. Forty-eight guinea pig carcasses were divided into four groups: 12 male and 12 female of 3 month-old fattened animals, and 12 male and 12 female of 12 month-old reproductive animals. The pH was measured using a penetration probe in Longissimus thoracis, Quadriceps femoris, Triceps brachii and Psoas major muscles for 24 h, and rigor mortis was monitored during this time. The initial and final pH ranged between 6.56–7.00 and 5.97–6.27, respectively. Rigor mortis was established at ∼5 h and resolved at ∼15 h postmortem. The Psoas major was the muscle with lower initial pH and higher final pH, while no differences were found between the other muscles. Initial, evolution and final pH were not affected by the sex. No differences were found in the productive-reproductive status between males, whereas the older female guinea pigs presented higher pH in three muscles. In conclusion, in our test conditions final pH in guinea pigs remains high enough to permit microbial growth, which could affect the shelf-life of Guinea pig meat. Moreover, it is recommended to keep guinea pig carcasses in refrigeration until 15 h postmortem, when rigor mortis is resolved, and muscle-to-meat conversion finished. Management of these carcasses should be different depending if the animals belong to a productive or reproductive animal system. It is therefore necessary to chill guinea pig carcasses at least 15 h, to achieve a correct muscle-to-meat conversion.
Sánchez-Macías, David; Cevallos-Velastegui, Lesllie; Nuñez-Valle, Diego; Morales-delaNuez, Antonio