Latitudinal pattern in community-wide herbivory does not match the pattern in herbivory averaged across common plant species

The latitudinal herbivory hypothesis (LHH) predicts that plant losses to herbivores decrease from low to high latitudes. Although the LHH is a community-level hypothesis, it has been rarely tested with data on community-wide herbivory, i.e. the percentage of annual production of foliar biomass consumed by insects from all plant species at a given site. Therefore, we asked whether community-wide leaf herbivory follows the same latitudinal pattern as observed for an unweighted average of herbivory across common plant species. We selected 10 study sites in boreal forests from 60 to 69 degrees N along a 1,000-km long latitudinal gradient in NW Russia. We measured relative foliar losses to insect herbivores in seven woody plant species (jointly comprising over 95% of the community-wide above-ground biomass) and estimated their current-year foliar biomass. We averaged leaf herbivory for all seven species and calculated community-wide leaf herbivory by weighting the relative foliar losses of each plant species against the contribution of that species to the annual foliar biomass production. Leaf herbivory was five-fold higher in deciduous species than in conifers. Latitudinal patterns in herbivory varied from a significant poleward decrease in all deciduous species to a significant poleward increase in Norway spruce. Herbivory values, averaged across seven plant species, decreased with latitude and followed the pattern observed in deciduous plants due to their higher foliar losses compared with conifers. By contrast, community-wide herbivory did not change with latitude. This discrepancy emerged because the proportion of deciduous plant foliage in the community increased with increasing latitude, and this increase counterbalanced the simultaneous poleward decrease in losses of these species to insects. Synthesis. The herbivory measured by averaging relative losses of individual plant species and community-wide herbivory is likely to show different latitudinal patterns in various plant communities. The contributions of plant species to the total foliar biomass production should be taken into account in studies of spatial patterns of herbivory which test community-level hypotheses. This approach may provide new insight into macroecological research on biotic interactions and improve our understanding of the role of insect herbivores in ecosystem-level processes

Orbitally induced hierarchy of exchange interactions in zigzag antiferromagnetic state of honeycomb silver delafossite Ag3Co2SbO6

We report the revised crystal structure, static and dynamic magnetic properties of quasi-two dimensional honeycomb-lattice silver delafossite Ag3Co2SbO6. The magnetic susceptibility and specific heat data are consistent with the onset of antiferromagnetic long range order at low temperatures with N\'eel temperature TN ~ 21.2 K. In addition, the magnetization curves revealed a field-induced (spin-flop type) transition below TN in moderate magnetic fields. The GGA+U calculations show the importance of the orbital degrees of freedom, which maintain a hierarchy of exchange interaction in the system. The strongest antiferromagnetic exchange coupling was found in the shortest Co-Co pairs and is due to direct and superexchange interactions between the half-filled xz+yz orbitals pointing directly to each other. The other four out of six nearest neighbor exchanges within the cobalt hexagon are suppressed, since for these bonds active half-filled orbitals turned out to be parallel and do not overlap. The electron spin resonance (ESR) spectra reveal a Gaussian shape line attributed to Co2+ ion in octahedral coordination with average effective g-factor g=2.3+/-0.1 at room temperature and shows strong divergence of ESR parameters below 120 K, which imply an extended region of short-range correlations. Based on the results of magnetic and thermodynamic studies in applied fields, we propose the magnetic phase diagram for the new honeycomb-lattice delafossite

Molecular genetic methods for identifying raw materials in meat products: Diversity, opportunities and prospects

In the current economic situation, after easing the Covid pandemic restrictions, almost all laboratories, which are focused on evaluation of the conformity of food products, have faced issues in supplying for their laboratories. In this regard, in the last years many laboratories have been forced to validate new approaches and introduce new methods for assessing conformity of the food products. Very often it is not possible to use only one method to resolve the issue of the food product ingredients, especially for the purpose of traceability of their names and the used raw materials, listed on the label. Survey of the raw food materials to determine whether they correspond to the type name is a simpler task, in contrast to survey of the multicomponent food product. Many researchers have to estimate the opportunities and feasibility of application of various methodologies in their workplaces. Therefore, this review is relevant for the researchers in this field, as it focuses on aspects and special features of similar methodologies. The prospect of molecular genetic methods for identification of the raw materials used for manufacturing of meat products is presented below. This review also represents characteristics of methods for identification of the sources of raw materials used for the manufacturing of the meat products, based on the recognition of species-specific sections within the nucleic acids structures. The variety of methods (hybridization methods, polymerase chain reaction, different types of isothermal amplifications, methods using CRISPR/Cas systems), the principles of their implementation, and achieved analytical characteristics are considered. The capacities and competitive potential of various methods are discussed, as well as approaches being developed to overcome the existing limitations.In the current economic situation, after easing the Covid pandemic restrictions, almost all laboratories, which are focused on evaluation of the conformity of food products, have faced issues in supplying for their laboratories. In this regard, in the last years many laboratories have been forced to validate new approaches and introduce new methods for assessing conformity of the food products. Very often it is not possible to use only one method to resolve the issue of the food product ingredients, especially for the purpose of traceability of their names and the used raw materials, listed on the label. Survey of the raw food materials to determine whether they correspond to the type name is a simpler task, in contrast to survey of the multicomponent food product. Many researchers have to estimate the opportunities and feasibility of application of various methodologies in their workplaces. Therefore, this review is relevant for the researchers in this field, as it focuses on aspects and special features of similar methodologies. The prospect of molecular genetic methods for identification of the raw materials used for manufacturing of meat products is presented below. This review also represents characteristics of methods for identification of the sources of raw materials used for the manufacturing of the meat products, based on the recognition of species-specific sections within the nucleic acids structures. The variety of methods (hybridization methods, polymerase chain reaction, different types of isothermal amplifications, methods using CRISPR/Cas systems), the principles of their implementation, and achieved analytical characteristics are considered. The capacities and competitive potential of various methods are discussed, as well as approaches being developed to overcome the existing limitations

Study of composite coal-water fuel rheological properties

© Published under licence by IOP Publishing Ltd. The rheological characteristics of composite water-coal fuel, as well as the possibility of reducing the viscosity of composite water-coal fuel due to the use of nanomaterials, are studied. Improved rheological properties of composite fuel containing small additions of these substances: carbon nanomaterial at a concentration of 0.005 wt. % or 0.3 wt. % of the dehydrated carbonate slurry. Possible mechanisms for changing the viscosity properties of fuel are considered

Synthesis and characterization of MnCrO4, a new mixed-valence antiferromagnet

A new orthorhombic phase, MnCrO4, isostructural with MCrO 4 (M = Mg, Co, Ni, Cu, Cd) was prepared by evaporation of an aqueous solution, (NH4)2Cr2O7 + 2 Mn(NO 3)2, followed by calcination at 400 C. It is characterized by redox titration, Rietveld analysis of the X-ray diffraction pattern, Cr K edge and Mn K edge XANES, ESR, magnetic susceptibility, specific heat and resistivity measurements. In contrast to the high-pressure MnCrO4 phase where both cations are octahedral, the new phase contains Cr in a tetrahedral environment suggesting the charge balance Mn2+Cr 6+O4. However, the positions of both X-ray absorption K edges, the bond lengths and the ESR data suggest the occurrence of some mixed-valence character in which the mean oxidation state of Mn is higher than 2 and that of Cr is lower than 6. Both the magnetic susceptibility and the specific heat data indicate an onset of a three-dimensional antiferromagnetic order at TN ≈ 42 K, which was confirmed also by calculating the spin exchange interactions on the basis of first principles density functional calculations. Dynamic magnetic studies (ESR) corroborate this scenario and indicate appreciable short-range correlations at temperatures far above T N. MnCrO4 is a semiconductor with activation energy of 0.27 eV; it loses oxygen on heating above 400 C to form first Cr 2O3 plus Mn3O4 and then Mn 1.5Cr1.5O4 spinel. © 2013 American Chemical Society

ИДЕНТИФИКАЦИЯ И КОЛИЧЕСТВЕННОЕ ОПРЕДЕЛЕНИЕ МЫШЕЧНОЙ ТКАНИ НА ОСНОВЕ КОНТРОЛЯ ПРОТОТИПИЧЕСКИХ ПЕПТИДОВ С ИСПОЛЬЗОВАНИЕМ МЕТОДА МОНИТОРИНГА ЗАДАННЫХ РЕАКЦИЙ

One of the main problems of modern production of meat products is the quality of raw meat, which depends on various factors including genetic components, conditions of transportation, production and processing. The most important components of meat are proteins, the total content, structure and functional state of which in this complex biological system with many interacting components is constantly changing. In order to study the interspecific and intraspecific features of meat proteins, their transformations in the process of maturation and processing requires modern analytical technologies based on the systematic approach to the analysis. Proteomics, as a methodology for studying proteins in a certain system and at a certain time, opens wide opportunities in this direction, allowing to identify and develop accurate analytical methods for searching biomarkers and identifying unfair practices. Given the high added value and multicomponent composition, finished meat products are among the most susceptible to adulteration. Current paper presents a technique of high-performance liquid chromatography with mass spectrometric detector (HPLC-MS) adapted for the detection and quantification of two different types of meat (beef and pork) in a complex biological matrix such as structureless minced meat. After the protein isolation and trypsin cleavage, species-specific peptide markers were selected for each animal species for the quantification. The technique was tested on model samples of a mixture of muscle tissue of the two species of animals. A good sensitivity was established with the possibility of quantitative determination of muscle tissue of each animal species using special calibration graphs. The developed technique can find wide application at the supervising organizations aimed at counteracting the discrepancies in the hidden replacement of types of meat by cheaper or low-grade raw materials.Keywords: Biomarker, prototypical peptides, HPLC-MS, species identification(Russian) DOI: http://dx.doi.org/10.15826/analitika.2019.23.4.012D.V. Khvostov1, N.L. Vostrikova1, A.V. Zherdev2, E.A. Zvereva2, A.A. Kurzova1  1V.M. Gorbatov Federal Research Center for Food Systems of Russian Academy of Sciences, 109316 Moscow, Russian Federation 2Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», Leninsky prospect, 33, build. 2, 119071 Moscow, Russian FederationОдной из основных проблем современного производства мясных продуктов является качество мясного сырья, которое зависит от разных факторов, включая генетические составляющие, условия транспортирования, производства и переработки. К наиболее значимым компонентам мяса относятся белки, общее содержание, структура и функциональное состояние которых в составе этой сложной биологической системы, с большим количеством взаимодействующих составляющих, постоянно изменяется. Для изучения межвидовых и внутривидовых особенностей белков мяса, трансформации их в процессе созревания и технологической обработки требуются современные аналитические технологии, основанные на системном подходе к анализу. Широкие возможности в этом направлении открывает протеомика, как методологии изучения белков в определенной системе и в определенное время, позволяющая идентифицировать и разрабатывать точные аналитические методы поиска биомаркеров и выявления недобросовестных практик. Учитывая высокую добавленную стоимость и многокомпонентность состава, готовые мясные продукты относятся к числу наиболее подверженных фальсификации. В работе представлена методика высокоэффективной жидкостной хроматографии с масс-спектрометрическим детектором (ВЭЖХ-МС), адаптированная для обнаружения и количественного определения двух различных видов мяса (говядина и свинина) в сложной биологической матрице, такой как бесструктурные фарши. После выделения белков и расщепления их трипсином были выбраны видоспецифичные пептидные маркеры для каждого вида животного с целью количественного определения. Методика была апробирована на модельных образцах смеси мышечной ткани двух видов животных. Установлена хорошая чувствительность с возможностью количественного определения мышечной ткани каждого вида животного, при использовании специальных градуировочных графиков. Разработанная методика может найти широкое применение у контролирующих организаций, направленных на противодействие несоответствиям по скрытой замене видов мяса более дешевым или низкосортными сырьем.Ключевые слова: Биомаркер, прототипические пептиды, ВЭЖХ-МС, видовая идентификацияDOI: http://dx.doi.org/10.15826/analitika.2019.23.4.01

Complex formation of d-metal ions at the interface of Tb III-doped silica nanoparticles as a basis of substrate-responsive TbIII-centered luminescence

The complex formation of d-metal ions at the interface of Tb III-doped silica nanoparticles modified by amino groups is introduced as a route to sensing d-metal ions and some organic molecules. Diverse modes of surface modification (covalent and noncovalent) are used to fix amino groups onto the silica surface. The interfacial binding of d-metal ions and complexes is the reason for the TbIII-centered luminescence quenching. The regularities and mechanisms of quenching are estimated for the series of d-metal ions and their complexes with chelating ligands. The obtained results reveal the interfacial binding of CuII ions as the basis of their quantitative determination in the concentration range 0.1-2.5 μM by means of steady-state and time-resolved fluorescence measurements. The variation of chelating ligands results in a significant effect on the quenching regularities due to diverse binding modes (inner or outer sphere) between amino groups at the interface of nanoparticles and FeIII ions. The applicability of the steady-state and time-resolved fluorescence measurements to sense both Fe III ions and catechols in aqueous solution by means of Tb III-doped silica nanoparticles is also introduced. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim