Pavlína Kyjaková

Fatty acid profiles of ecotypes of hyperaccumulator Noccaea caerulescens growing under cadmium stress

Changes in the fatty acid (FAs) composition in response to the extent of Cd contamination of soils (0, 30, 60 and 90 mg Cd kg(-1)) differed between ecotypes of Noccaea caerulescens originating from France - Ganges, Slovenia - Mežica and Austria - Redlschlag. Mežica ecotype accumulated more Cd in aboveground biomass compared to Ganges and Redlschlag ecotypes. Hyperaccumulators contained saturated fatty acids (SFAs) rarely occurring in plants, as are cerotic (26:0), montanic (28:0), melissic (30:0) acids, and unusual unsaturated fatty acids (USFAs), as are 16:2, 16:3, 20:2 and 20:3. Typical USFAs occurring in the family Brassicaceae, such as erucic, oleic and arachidonic acids, were missing in tested plants. Our results clearly indicate a relationship between Cd accumulation and the FAs composition. The content of SFAs decreased and the content of USFAs increased in aboveground biomass of Ganges and Mežica ecotypes with increasing Cd concentration. Opposite trend of FAs content was determined in Redlschlag ecotype. Linoleic (18:2n-6), α-linolenic (18:3n-3) and palmitic (16:0) acids were found in all ecotypes. The results observed in N. caerulescens ecotypes, showed that mainly Mežica ecotype has an efficient defense strategies which can be related on changes in FAs composition, mainly in VLCFAs synthesis. The most significant effect of ecotype on FAs composition was confirmed using multivariate analysis of variance.

Changes in the contents of amino acids and the profile of fatty acids in response to cadmium contamination in spinach.

Changes of amino acid (AAs) contents (glutamic acid – Glu, aspartic acid – Asp) and fatty acids profile (FAs) in spinach under cadmium (Cd) soil contamination (Cd1 = 30, Cd2 = 60, Cd3 = 90 mg/kg soil) are reported here. Spinach plants were sampled 25, 40, 55 and 75 days after sowing. Growing Cd soil contamination was associated with the strong inhibition of above-ground biomass (23.5–6.3 g dry matter per pot) and with the enhancement of Cd content (0.60–72.38 mg/kg dry matter) in leaves. During 55 days of plant growing the increase of Glu and Asp content was associated with the enhancement of Cd content. The highest accumulation of AAs was determined on Cd3 treatment after 55 days of cultivation. Strong decreases of both AAs were confirmed in the last sampling peri od for Cd treatments (reduction of Glu content of Cd3 treatment to ca. 64% and Asp content to ca. 72% in contrast to control). The content of saturated fatty acids increased (mainly palmitic acid) and the content of unsaturated fatty acids decreased in spinach aboveground biomass with increasing Cd concentration. Results of multivariate analysis of variance MANOVA showed the significant effect of Cd contamination for FAs metabolism, but the most significant effect was confirmed for plant growing period.

Smells Like Home: Chemically Mediated Co-Habitation of Two Termite Species in a Single Nest

Termite nests often are referred to as the most elaborate constructions of animals. However, some termite species do not build a nest at all and instead found colonies inside the nests of other termites. Since these so-called inquilines do not need to be in direct contact with the host population, the two colonies usually live in separate parts of the nest. Adaptations of both the inquiline and its host are likely to occur to maintain the spatial exclusion and reduce the costs of potential conflicts. Among them, mutual avoidance, based on chemical cues, is expected. We investigated chemical aspects of cohabitation between Constrictotermes cavifrons (Nasutitermitinae) and its obligatory inquiline Inquilinitermes inquilinus (Termitinae). Inquiline soldiers produce in their frontal glands a blend of wax esters, consisting of the C12 alcohols (3Z)-dodec enol, (3Z,6Z)-dodecadienol, and dodecanol, esterified with different fatty acids. The C12 alcohols appear to be cleaved gradually from the wax esters, and they occur in the frontal gland, in soldier headspace, and in the walls of the inquiline part of the nest. Electrophysiological experiments revealed that (3Z)-dodecenol and (3Z,6Z)-dodecadienol are perceived by workers of both species. Bioassays indicated that inquiline soldier heads, as well as the two synthetic compounds, are attractive to conspecific workers and elicit an arresting behavior, while host soldiers and workers avoid these chemicals at biologically relevant amounts. These observations support the hypothesis that chemically mediated spatial separation of the host and the inquiline is an element of a conflict-avoidance strategy in these species.

Mitochondrial and chemical profiles reveal a new genus and species of Neotropical termite with snapping soldiers, Palmitermes impostor (Termitidae : Termitinae)

Abstract. Since the inception of Linnaean taxonomy, termite species and genus descriptions have been mostly based on the morphology of soldiers, sometimes complemented by alate characters, though these are seldom discriminant. However, narrowly soldier-based descriptions may overemphasise ancestral characters and lead to the establishment of non-monophyletic taxa. In this paper, we used an integrative taxonomic approach that incorporates the morphology of all castes, including workers, as well as molecular and chemical data, to describe Palmitermes impostor Hellemans & Roisin, 2017 (Termitidae : Termitinae), a new termite genus and species from French Guiana. Although the soldiers of P. impostor resemble those of Termes Linnaeus, 1758, the digestive tract and mandibles of workers suggest that Palmitermes is closely related to Cavitermes Emerson, 1925. The sister-group relationship between Palmitermes and Cavitermes was confirmed by a phylogenetic reconstruction based on full mitochondrial genome sequences as well as by the comparison of the profiles of cuticular hydrocarbons of workers with those of related taxa. Our study illustrates the benefits of using an integrative taxonomic approach to describe new taxa and the pitfalls of using soldier morphology as the exclusive set of characters in termite systematics.

Regulation of odd-numbered fatty acid content plays an important part in the metabolism of the hyperaccumulator Noccaea spp. adapted to oxidative stress

Relatively little is known about why odd-numbered fatty acids (OFAs) can be synthesized only by some plant species. We aimed at determining whether there is a relationship between the effects of Cd-induced oxidative stress on unsaturated fatty acids (USFAs) and their degradation products, especially OFAs. Plants with different ability to accumulate Cd - Noccaea praecox from Mežica, Slovenia (Me) and two ecotypes of Noccaea caerulescens from Ganges, France (Ga) and Redlschlag, Austria (Re) were cultivated in pot experiments. Only Me plants contained OFA 13:0, while all plants contained OFAs 15:0, 17:0 and 23:0 but in different proportions. Mutual correlations showed a significant effect of Cd contamination on the content of OFAs and USFAs in Me, a less pronounced effect in Re and the lowest one in Ga plants. The most significant correlation between the contents of USFAs and OFAs was also calculated for Me plants. The correlations between OFAs and USFAs indicate an active participation of OFA in FAs metabolism. Increased efficiency of utilization of the assimilated carbon via OFAs metabolism of Me plants in contrast to Re and Ga is also reflected in the increase of tolerance of Me plants to Cd toxicity in plant cells.

Identification and Enantiodivergent Synthesis of (5Z,9S)-Tetradec-5-en-9-olide, a Queen-Specific Volatile of the Termite Silvestritermes minutus

The queens of social insects differ from sterile colony members in many aspects of their physiology. Besides adaptations linked with their specialization for reproduction and extended lifespan, the queens also invest in the maintenance of their reproductive dominance by producing exocrine chemicals signaling their presence to the nestmates. The knowledge of the chemistry of queen-specific cues in termites is scarce. In addition to the contact recognition based on cuticular hydrocarbons, long-range signals mediated by volatiles are expected to participate in queen signaling, especially in populous colonies of higher termites (Termitidae). In queens of the higher termite Silvestritermes minutus (Syntermitinae), we have detected a previously undescribed volatile. It is present in important quantities on the body surface and in the headspace, ovaries, and body cavity. MS and GC-FTIR data analyses led us to propose the structure of the compound to be a macrolide 10-pentyl-3,4,5,8,9,10-hexahydro-2 H-oxecin-2-one. We performed enantiodivergent syntheses of two possible enantiomers starting from enantiopure ( S)-glycidyl tosylate. The synthetic sequence involved macrolide-closing metathesis quenched with a ruthenium scavenging agent. The absolute and relative configuration of the compound was assigned to be (5 Z,9 S)-tetradec-5-en-9-olide. Identification and preparation of the compound allow for investigation of its biological significance.