The Role of Silicon in Antiherbivore Phytohormonal Signalling

The role of plant silicon (Si) in the alleviation of abiotic and biotic stress is now widely recognised and researched. Amongst the biotic stresses, Si is known to increase resistance to herbivores through biomechanical and chemical mechanisms, although the latter are indirect and remain poorly characterised. Chemical defences are principally regulated by several antiherbivore phytohormones. The jasmonic acid (JA) signalling pathway is particularly important and has been linked to Si supplementation, albeit with some contradictory findings. In this Perspectives article, we summarise existing knowledge of how Si affects JA in the context of herbivory and present a conceptual model for the interactions between Si and JA signalling in wounded plants. Further, we use novel information from the model grass Brachypodium distachyon to underpin aspects of this model. We show that Si reduces JA concentrations in plants subjected to chemical induction (methyl jasmonate) and herbivory (Helicoverpa armigera) by 34% and 32%, respectively. Moreover, +Si plants had 13% more leaf macrohairs than −Si plants. From this study and previous work, our model proposes that Si acts as a physical stimulus in the plant, which causes a small, transient increase in JA. When +Si plants are subsequently attacked by herbivores, they potentially show a faster induction of JA due to this priming. +Si plants that have already invested in biomechanical defences (e.g. macrohairs), however, have less utility for JA-induced defences and show lower levels of JA induction overall

Absorption, metabolism and biological role of nucleic acids present in food

Kwasy nukleinowe należą do niedocenianych składników żywności, szczególnie surowej lub nisko przetworzonej. W niniejszej publikacji skupiono się na omówieniu przemian, jakim podlegają kwasy nukleinowe w przewodzie pokarmowym człowieka, procesie absorpcji nukleotydów oraz nukleozydów z przewodu pokarmowego, a także przedstawiono podstawowe etapy ich metabolizmu w komórkach organizmu. Produkty trawienia kwasów nukleinowych stanowią źródło ważnych cząsteczek sygnalizacyjnych i prekursorowych, mogą być również ponownie wykorzystane do budowy nowych cząsteczek kwasów nukleinowych w organizmie człowieka. W ostatnich latach największe zainteresowanie wzbudzają niskocząsteczkowe kwasy nukleinowe, takie jak niekodujące RNA (ncRNA), także obecne w żywności. Sugeruje się możliwość oddziaływania pokarmowego ncRNA na poziomie regulacji ekspresji genów w komórkach przewodu pokarmowego, a być może i innych tkankach konsumenta. Zarówno wartość odżywcza, jak i wpływ spożywanych kwasów nukleinowych na funkcjonowanie genomu i transkryptomu wskazują na konieczność rozpatrywania żywienia człowieka w kontekście nutrigenomiki.Nucleic acids are one of the underestimated ingredients in food, especially in the raw or low-processed food products. The paper focuses on discussing conversions in nucleic acids that occur in the human digestive tract, on absorption processes of nucleosides and nucleotides from the gastrointestinal tract; also, the basic steps of their metabolism in the cells of the organism are presented. Digestion products of the nucleic acids are a valuable source of important signalling and precursor molecules. They may also be utilized to form new nucleic acid molecules in the human body. In recent years, low-molecular weight nucleic acids catch most interest, such as non-coding RNA (ncRNA), which are also present in food. It is suggested that the dietary ncRNA can probably impact the regulation of gene expression in the cells of the gastrointestinal tract, and perhaps in other tissues of the consumer. Both the nutritional value and the impact of nucleic acids consumed on the functioning of the genome and transcriptome suggest the need to look into human nutrition in the context of nutrigenomics

Subcommutativity of integrals and quasi-arithmetic means

Let $(X, \mathscr{L}, \lambda)$ and $(Y, \mathscr{M}, \mu)$ be finite measure spaces for which there exist $A \in \mathscr{L}$ and $B \in \mathscr{M}$ with either $0 < \lambda(A) < 1 < \lambda(X)$ and $0 < \mu(B) < \mu(Y)$, or the other way around. In addition, let $I \subseteq \mathbb{R}$ be a non-empty open interval, and suppose that $f,g\colon I \to \mathbb{R}_{+}$ are homeo\-morphisms with $g$ increasing. We prove that the functional inequality $$f^{-1}\!\left(\int_X f\!\left(g^{-1}\!\left(\int_Y g \circ h\;d\mu\right)\right)d \lambda\right)\! \le g^{-1}\!\left(\int_Y g\!\left(f^{-1}\!\left(\int_X f \circ h\;d\lambda\right)\right)d \mu\right)$$ is satisfied by every $\mathscr{L} \otimes \mathscr{M}$-measurable simple function $h: X \times Y \to I$ if and only if $f=a g^b$ for some $a,b \in \mathbb{R}_{+}$ with $b\ge 1$. An analogous characterization is given for probability spaces

Commutativity of Integral Quasi-Arithmetic Means on Measure Spaces

Let (X, L, λ) and (Y, M, μ) be finite measure spaces for which there exist A∈ L and B∈ M with 0 &lt; λ(A) &lt; λ(X) and 0 &lt; μ(B) &lt; μ(Y) , and let I⊆ R be a non-empty interval. We prove that, if f and g are continuous bijections I→ R+, then the equation (Formula Presented.) is satisfied by every L⊗ M-measurable simple function h: X× Y→ I if and only if f = cg for some c∈ R+ (it is easy to see that the equation is well posed). An analogous, but essentially different result, with f and g replaced by continuous injections I→ R and λ(X) = μ(Y) = 1 , was recently obtained in [7]