Comparison of two noninvasive methods for measuring the pigment content in foliose macrolichens.

Chlorophyll content in lichens is routinely used as an accurate indicator of lichen vigor, interspecific differences, and the effect of site-related environmental parameters. Traditional methods of chlorophyll extraction are destructive, time-consuming, expensive, and inoperable, especially when measuring large quantities of chlorophyll. However, non-destructive methods of measurement using portable chlorophyll meters are rarely used for lichens. Considering the characteristics of lichens such as rough blade surface and absence of chlorophyll b in cyanolichens, we compared the non-destructive methods with traditional methods and evaluated their applicability in studying lichen pigment content. Two instruments, SPAD-502 and CCM-300, were used to measure the pigment content of seven foliose lichen species. These pigment readings were compared with those determined using the dimethyl sulphoxide (DMSO) extraction method. Significant correlations were observed between SPAD/CCM values and pigments (chlorophyll and total carotenoids) extracted from chlorolichens, especially species with a smooth surface. The CCM-300 was more accurate in detecting the pigment content of foliose chlorolichens. However, both instruments showed certain limitations in the determination of pigment content in cyanolichens, especially gelatinous species. For example, CCM-300 often failed to give specific values for some cyanolichen samples, and both instruments showed low measurement accuracy for cyanolichens. Based on the high correlation observed between chlorophyll meter readings and pigments extracted from chlorolichens, equations obtained in this study enabled accurate prediction of pigment content in these lichens.

Crocin attenuates acute hypobaric hypoxia-induced cognitive deficits of rats.

This study investigated whether crocin exerted neuroprotective effects against acute hypobaric hypoxia at high altitude in vivo and determined the underlying mechanisms. Male Sprague-Dawley rats were randomly assigned to a normoxic group，a hypoxic group, and three crocin groups at three different doses. The rats were transferred from 50m to 4200m for 3 days after treatment with crocin for 3 days. The learning and memory of the rat were evaluated with the Morris water maze test. Transmission electron microscope (TEM) was used to analyze the changes in the ultrastructure of hippocampal neurons. Peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α) and sirtuin-1 (SIRT1) levels were determined using immunohistochemical staining and western blotting. The escape latency of the crocin group was shorter than that of the hypoxic group, while the frequency of the rats reaching the platform was significantly higher in the crocin group. The structures of nerve cells and mitochondria were destroyed in the hypoxic group, but were repaired in the crocin groups. The expressions of PGC-1α and SIRT1 were decreased in the hypoxic group, but were increased in the crocin group. All the effects improved by crocin were dose-dependent. Crocin attenuates acute hypobaric hypoxia-induced cognitive deficits in rats, accompanied by repairing the structures of hippocampal neurons and improving PGC-1α and SIRT1 levels.