Development of electrospun mats based on hydrophobic hydroxypropyl cellulose derivatives.

In this work, hydroxypropyl cellulose esters (HPCE) with long aliphatic chains were prepared and innovatively used in electrospinning to obtain hydroxypropyl cellulose (HPC)-based mats with enhanced resistance to moist environments. The described approach is very simple and does not require any post-treatment (e.g. cross-linking step) to overcome a major problem concerning the premature loss of properties of cellulose-based materials when in contact with moisture. HPCE-based electrospun mats were characterized in terms of their morphology, swelling ability and in vitro hydrolytic degradation. The mats exhibited a swelling capacity of over 115%, depending on the degree of substitution. The in vitro hydrolytic degradation tests showed the high structural integrity of the mats (< 5% weight loss) over a period of 30 days. The in vitro cytotoxicity tests showed that the mats of HPC esters are cytocompatible and promote the adhesion, proliferation and spreading of NIH3T3 fibroblast cells. These data suggest that the HPCE mats may be interesting materials for wound dressings, as well as for other tissue engineering applications.

Negative impact on the reproductive potential of blue jack mackerel Trachurus picturatus by Kudoa infection of the ovary.

Reproduction of Trachurus picturatus off the western Portuguese coast was studied over 1 yr. During histological analyses, the presence of Kudoa sp. was detected in advanced vitellogenic oocytes. Kudoa infections are known to cause economic loss through the induction of post-mortem liquefaction of fish muscles, but ovarian infection as reported in this study will seriously affect the reproductive potential of the species and thus impact fisheries productivity. Only females showed gonad infection which led to total degradation of advanced vitellogenic oocytes. No macroscopic, somatic or condition indices revealed differences between infected and uninfected females, rendering this infection event a concealed suppression of reproduction.

Warm vegetarians? Heat waves and diet shifts in tadpoles.

Temperature can play an important role in determining the feeding preferences of ectotherms. In light of the warmer temperatures arising with the current climatic changes, omnivorous ectotherms may perform diet shifts toward higher herbivory to optimize energetic intake. Such diet shifts may also occur during heat waves, which are projected to become more frequent, intense, and longer lasting in the future. Here, we investigated how heat waves of different duration affect feeding preferences in omnivorous anuran tadpoles and how these choices affect larval life history. In laboratory experiments, we fed tadpoles of three species on animal, plant, or mixed diet and exposed them to short heat waves (similar to the heat waves these species experience currently) or long heat waves (predicted to increase under climate change). We estimated the dietary choices of tadpoles fed on the mixed diet using stable isotopes and recorded tadpole survival and growth, larval period, and mass at metamorphosis. Tadpole feeding preferences were associated with their thermal background, with herbivory increasing with breeding temperature in nature. Patterns in survival, growth, and development generally support decreased efficiency of carnivorous diets and increased efficiency or higher relative quality of herbivorous diets at higher temperatures. All three species increased herbivory in at least one of the heat wave treatments, but the responses varied among species. Diet shifts toward higher herbivory were maladaptive in one species, but beneficial in the other two. Higher herbivory in omnivorous ectotherms under warmer temperatures may impact species differently and further contribute to changes in the structure and function of freshwater environments.