Interpopulation Variability in the Essential Oil Composition of Cistus creticus subsp. eriocephalus from Sardinia.

Cistus genus is widespread in the Mediterranean regions with several species and is traditionally known as a natural remedy, but few previous phytochemical researches have been reported on Cistus species growing in Sardinia. The aim of this work was to study the interpopulation variability of the volatiles of C. creticus subsp. eriocephalus to find out the natural chemotypes of this taxon for chemotaxonomic purposes. Plant material was collected from seven wild populations in Sardinia. The oils from aerial part were obtained by hydrodistillation and analyzed by GC/MS enabling to identify 185 compounds. The seven samples showed appreciable variations in their chemical composition. MA was found almost exclusively linear hydrocarbons (85%) and MN presented fatty acids (36.97%) as major fraction. CP and MN had high quantity of non-terpenic carbonylic compounds (63% and 69%, respectively) and in CP was found also sclareol, a well-known antimicrobial compound. PCA analysis showed the existence of a high interpopulation variability within the essential oils of C. creticus subsp. eriocephalus growing in Sardinia. For example, MN and CP are very close to each other as CG is close to PM. BN is isolated from the others Cistus populations due to lacking essential oil. These data suggest that the basis of variation in the volatile composition of seven C. creticus subsp. eriocephalus populations depends on hybridization and that the sample without essential oil is the only one no-hybridized.

Indication of the impact of environmental stress on the responses of the bivalve mollusk Unio tumidus to ibuprofen and microplastics based on biomarkers of reductive stress and apoptosis.

The vulnerability of bivalve mollusks to micropollutants is estimated mainly in single model exposures. However, chronic environmental stress and complex exposures can modulate their responses. To evaluate the impact of population-dependent adaptations on the ability to react to common micropollutants, we compared freshwater bivalves Unio tumidus from two distinct populations, pure (Pr) and contaminated (Ct), in their exposures to microplastics (MP, 1 mg L-1, size 0.1-0.5 mm), pharmaceutical ibuprofen (IBU, 0.8 µg L-1), or their combination (Mix) for 14 days. Control groups from both sites showed remarkable differences, with lower levels of total antioxidant capacity (TAC), metallothionein protein (MTSH), NADH and NAD+, cytochrome P450-related EROD, glutathione-S transferase (GST), and citrate synthase (CS) but higher levels of GSH, GSSG, caspase-3 and cathepsin D (CTD) in the Ct-control group. These data indicate a chronic stress impact in the Ct population. Under exposures, we found an almost common strategy in both populations for NAD+/NADH and MTSH suppression and CTD induction. Additionally, Mix exposure caused an increase in CS, and IBU did not change GSH in both populations. However, the expected response to IBU - the suppression of caspase-3 - was indicated only in PrIBU- and PrMix-mollusks. CTD efflux increased dramatically only in PrMP- and PrMix- groups, and suppression of EROD and GST was detected in the PrMix-group. According to discriminant analysis, exposed Pr-groups were highly differentiated from control, whereas Ct-control and exposed groups had common localization demonstrating high resistance to environmental stress. Thus, the same exposures resulted in different adverse outcome pathways depending on the population.

Morphological variability and genetic diversity in Carex buxbaumii and Carex hartmaniorum (Cyperaceae) populations.

BACKGROUND: Carex buxbaumii and C. hartmaniorum are sister species of the clade Papilliferae within the monophyletic section Racemosae. An unambiguous identification of these species is relatively difficult due to the interspecific continuum of some morphological characters as well as the intraspecific variability. The study was aimed at determining the range of variability, both morphological and genetic, within and between these two closely related and similar species. METHODS: The sedges were collected during botanical expeditions to Armenia, Estonia, the Netherlands, and Poland. The morphological separation of the two species and their populations was tested using the Discriminant Function Analysis (DFA). The genetic variability of the 19 Carex populations was assessed in the presence of eight Inter Simple Sequence Repeat (ISSR) primers. RESULTS: Results of the study indicate a considerable genetic affinity between the two sedge species (mean Si = 0.619). However, the populations of C. hartmaniorum are, morphologically and genetically, more homogenous than the populations of C. buxbaumii. Compared to C. hartmaniorum, C. buxbaumii usually has wider leaf blades, a shorter inflorescence, a lower number of spikes which are shorter, but wider, and longer bracts and utricles. The AMOVA showed a larger variation between the populations of C. buxbaumii, representing 25.65% of the total variation in the taxon. Two populations of C. buxbaumii (from Poland and Estonia) are separated from the remaining populations, both genetically and morphologically; their individuals show shorter utricles and glumes, compared to the typical specimens of C. buxbaumii, and correspond with the morphology of putative infraspecific taxa described by Cajander (var. brevisquamosa and var. confusa). CONCLUSIONS: The taxonomic status of the putative infraspecific taxa within C. buxbaumii requires further studies throughout the distribution range of C. buxbaumii, addressing habitats, morphology and genetics (including a chromosome count or a combination of different genetic methods), particularly as the variability in C. buxbaumii may be associated with the species' polyploid origin.

Analysis of intraspecific seed diversity in Astragalus aquilanus (Fabaceae), an endemic species of Central Apennine.

This work aims to study seeds of the endemic species Astragalus aquilanus from four different populations of central Italy. We investigated seed morpho-colorimetric features (shape and size) and chemical differences (through infrared spectroscopy) among populations and between dark and light seeds. Seed morpho-colorimetric quantitative variables, describing shape, size and colour traits, were measured using image analysis techniques. Fourier transform infrared (FT-IR) spectroscopy was used to attempt seed chemical characterisation. The measured data were analysed by step-wise linear discriminant analysis (LDA). Moreover, we analysed the correlation between the four most important traits and six climatic variables extracted from WorldClim 2.0. The LDA on seeds traits shows clear differentiation of the four populations, which can be attributed to different chemical composition, as confirmed by Wilk's lambda test (P < 0.001). A strong correlation between morphometric traits and temperature (annual mean temperature, mean temperature of the warmest and coolest quarter), colorimetric traits and precipitation (annual precipitation, precipitation of wettest and driest quarter) was observed. The characterisation of A. aquilanus seeds shows large intraspecific plasticity both in morpho-colorimetric and chemical composition. These results confirm the strong relationship between the type of seed produced and the climatic variables.

Population-associated heterogeneity of the digestive Cys protease complement in Colorado potato beetle, Leptinotarsa decemlineata.

Herbivorous insects use complex protease complements to process plant proteins, useful to adjust their digestive functions to the plant diet and to elude the antidigestive effects of dietary protease inhibitors. We here assessed whether basic profiles and diet-related adjustments of the midgut protease complement may vary among populations of the insect herbivore Colorado potato beetle (Leptinotarsa decemlineata). Two laboratory colonies of this insect were used as models, derived from insect samples collected in potato fields ∼1200km distant from each other in North America. Synchronized 4th-instar larvae reared on potato were kept on this plant, or switched to tomato or eggplant, to compare their midgut cathepsin activities and content of intestain Cys proteases under different diet regimes. Cathepsin D activity, cathepsin L activity, cathepsin B activity and total intestain content shortly after larval molting on potato leaves were about two times lower in one population compared to the other. By comparison, cathepsin D activity, cathepsin B activity, total intestain content and relative abundance of the most prominent intestain families were similar in the two populations after three days regardless of the plant diet, unlike cathepsin L activity and less prominent intestain families showing population-associated variability. Variation in Cys protease profiles translated into the differential efficiency of a Cys protease inhibitor, tomato cystatin SlCYS8, to inhibit cathepsin L activity in midgut extracts of the two insect groups. Despite quantitative differences, SlCYS8 single variants engineered to strongly inhibit Cys proteases showed improved potency against cathepsin L activity of either population. These data suggest the feasibility of designing cystatins to control L. decemlineata that are effective against different populations of this insect. They underline, on the other hand, the practical relevance of considering natural variability of the protease complement among L. decemlineata target populations, eventually determinant in the success or failure of cystatin-based control strategies on a large-scale basis.

By-product of Lavandula latifolia essential oil distillation as source of antioxidants.

The objective of this work was to evaluate the antioxidant properties of Lavandula latifolia waste obtained after essential oil distillation. Samples of 12 wild populations of the Lavandula genus collected between 2009 and 2010 were hydrodistilled and their by-products were analyzed using the Folin-Ciocalteu, free radical scavenging activity (2,2-diphenyl-1-picrylhydrazyl), and the ferric reducing antioxidant power (FRAP) methods. Rosmarinic acid, apigenin, and luteolin contents were analyzed by high-performance liquid chromatography-diode array detection. The mean of total phenolic content ranged from 1.89 ± 0.09 mg gallic acid equivalents/g dry weight to 3.54 ± 0.22 mg gallic acid equivalents/g dry weight. The average value of the half maximal effective concentration (EC50) for scavenging activity ranged from 5.09 ± 0.17 mg/mL to 14.30 ± 1.90 mg/mL and the variability of the EC50 in FRAP ranged from 3.72 ± 0.12 mg/mL to 18.55 ± 0.77 mg/mL. Annual variation was found among this samples and the environmental conditions of 2009 were found to be more favorable. The plants collected from Sedano showed the highest antioxidant power. Our results show that rosmarinic acid and apigenin in L. latifolia contributed to the antioxidant properties of the waste. In conclusion, the by-product of the distillation industry could be valorizing as a source of natural antioxidants.