Cryo-EM demonstrates the in vitro proliferation of an ex vivo amyloid fibril morphology by seeding

Several studies showed that seeding of solutions of monomeric fibril proteins with ex vivo amyloid fibrils accelerated the kinetics of fibril formation in vitro but did not necessarily replicate the seed structure. In this research we use cryo-electron microscopy and other methods to analyze the ability of serum amyloid A (SAA)1.1-derived amyloid fibrils, purified from systemic AA amyloidosis tissue, to seed solutions of recombinant SAA1.1 protein. We show that 98% of the seeded fibrils remodel the full fibril structure of the main ex vivo fibril morphology, which we used for seeding, while they are notably different from unseeded in vitro fibrils. The seeded fibrils show a similar proteinase K resistance as ex vivo fibrils and are substantially more stable to proteolytic digestion than unseeded in vitro fibrils. Our data support the view that the fibril morphology contributes to determining proteolytic stability and that pathogenic amyloid fibrils arise from proteolytic selection.

The problem of vicarious and other categories of species of Euonymus L. (Celastraceae) from Northern Eurasia: The carpological approach

Among the species of Euonymus L. of the flora of Russia and adjacent territories, various scholars identify vicarious, endemic and relict species; their arguments and proofs are often incomplete and controversial. The present paper is dedicated to the critical analysis of all available data used for the substantiation of the status (category) of a given species. The authors employ both original and literature data on morphology, anatomy, chromosome numbers, DNA sequences, geography and ecology of species of Euonymus. The complex of morphological and anatomical traits of fruits instrumental for the existence of closely related species in different conditions is analyzed. Special focus is paid to the correlation between the size of geographical range, fruit and seed structure and dispersal type is discussed, as well as other factors (historical, ecological) affecting taxa migration. This determines the resolving capabilities of carpological approach developed by the authors. As a result of our research, we came to the following conclusions: E. europaeus, E. maackii, E. sieboldianus and E. bungeanus are georgraphic vicariants; E. hamiltonianus and E. sieboldianus are ecological vicariants; E. velutinus is not a vicarious species; E. verrucosus and E. pauciflorus are not vicarious; E. alatus and E. sacrosanctus are hereby considered ecological vicariants; E. nanus and E. koopmannii are geographic vicariants; E. leiophloeus are apparently not vicarious; E. latifolius, E. sachalinensis and E. maximowiczianus are hereby treated as geographic vicariants. E. leiophloeus appears to be a regional endemic; we consider E. maximowiczianus and E. velutinus to be subendemic species. Additionally, E. nanus is considered as relict taxon.

Impact of Germination on the Microstructural and Physicochemical Properties of Different Legume Types

The microstructural and physicochemical compositions of bean (Phaseolus vulgaris), lentil (Lens culinaris Merr.), soybean (Glycine max L.), chickpea (Cicer aretinium L.) and lupine (Lupinus albus) were investigated over 2 and 4 days of germination. Different changes were noticed during microscopic observations (Stereo Microscope, SEM) of the legume seeds subjected to germination, mostly related to the breakages of the seed structure. The germination caused the increase in protein content for bean, lentil, and chickpea and of ash content for lentil, soybean and chickpea. Germination increased the availability of sodium, magnesium, iron, zinc and also the acidity for all legume types. The content of fat decreased for lentil, chickpea, and lupine, whereas the content of carbohydrates and pH decreased for all legume types during the four-day germination period. Fourier transform infrared spectroscopic (FT-IR) spectra show that the compositions of germinated seeds were different from the control and varied depending on the type of legume. The multivariate analysis of the data shows close associations between chickpea, lentil, and bean and between lupine and soybean samples during the germination process. Significant negative correlations were obtained between carbohydrate contents and protein, fat and ash at the 0.01 level.

DEFINITION OF ORCHIDS (ORCHIDACEAE) OF THE SOCHI BLACK SEA REGION BY MICROMORPHOLOGICAL CHARACTERISTICS OF SEEDS

According to the results of preliminary studies of the micromorphology of orchids seeds in the Sochi Black Sea region, a key has been compiled to identify 25 species and subspecies from 13 genera by seed. The most valuable features of seed structure for diagnosis were identified from the previously described characteristics: seed shape, its length, the number of cells in testa, their shape in different parts of testa. Limodorum-type seeds have fusiform, linear or balloon-shape and Orchis-type seeds are pear-shaped or club-shaped. The shape of the cells is the same throughout the testa or contrasting one – elongated in the micropylar and medial parts and isodiametric at the chalazal pole. This trait also distinguishes the type of seed. Some genera are characterized by convoluted or smooth anticlinal cell walls. The periclinal walls of the cells have sculptural thickenings of different patterns, or no pattern. This feature consistently characterizes different genera and even species. Frequent or rare stripes of the sculpture, mostly straight or curved, forming gaps at the borders of cells or not – these features are species-specific. Relative sizes, in particular, the ratio of the length of a seed to the length of an embryo, as well as the proportion of sizes of parts of seed coats have great specificity. On the contrary, orientation of the strokes of the sculpture, the presence of suspension residues and the degree of homogeneity of an embryo are not reliable diagnostic features. The key is useful for field researches for studying the distribution of orchids in the period after flowering and until the seeds are completely dispersed.

Yield and seed structure of the spring wheat

We presented analysis of the influence of spring wheat seeds sowing qualities on the yield. Experimental studies were carried out in 2010-2017 in Altai Krai. The seed divided into fractions in the air stream differs significantly in its characteristics. The ratio of fractions significantly depends on the conditions of the year and has a significant impact on the formation of the potential yield of spring wheat. Seeds isolated at an air speed of 8 m/s are a highly significant limiting factor in achieving the maximum yield of spring wheat. An increase in their share for every 10% in the seed can lead to a yield shortfall of up to 5.5 c/ha. Sowing should be carried out with the most complete seed fractions, with a 1000 grain weight of 31.8-38.0 g, obtained at an air flow rate of 9 m/s. Their share in the seed used by the farms of the region is 34.8 - 52.7%.

Functional role of yeasts, lactic acid bacteria and acetic acid bacteria in cocoa fermentation processes

ABSTRACT Cured cocoa beans are obtained through a post-harvest, batchwise process of fermentation and drying carried out on farms in the equatorial zone. Fermentation of cocoa pulp-bean mass is performed mainly in heaps or boxes. It is made possible by a succession of yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) activities. Yeasts ferment the glucose of the cocoa pulp into ethanol, perform pectinolysis and produce flavour compounds, such as (higher) alcohols, aldehydes, organic acids and esters. LAB ferment the glucose, fructose and citric acid of the cocoa pulp into lactic acid, acetic acid, mannitol and pyruvate, generate a microbiologically stable fermentation environment, provide lactate as carbon source for the indispensable growth of AAB, and contribute to the cocoa and chocolate flavours by the production of sugar alcohols, organic acids, (higher) alcohols and aldehydes. AAB oxidize the ethanol into acetic acid, which penetrates into the bean cotyledons to prevent seed germination. Destruction of the subcellular seed structure in turn initiates enzymatic and non-enzymatic conversions inside the cocoa beans, which provides the necessary colour and flavour precursor molecules (hydrophilic peptides, hydrophobic amino acids and reducing sugars) for later roasting of the cured cocoa beans, the first step of the chocolate-making.

Internal Seed Structure of Alpine Plants and Extreme Cold Exposure

Cold tolerance in seeds is not well understood compared to mechanisms in aboveground plant tissue but is crucial to understanding how plant populations persist in extreme cold conditions. Counter-intuitively, the ability of seeds to survive extreme cold may become more important in the future due to climate change projections. This is due to the loss of the insulating snow bed resulting in the actual temperatures experienced at soil surface level being much colder than without snow cover. Seed survival in extremely low temperatures is conferred by mechanisms that can be divided into freezing avoidance and freezing tolerance depending on the location of ice crystal formation within the seed. We present a dataset of alpine angiosperm species with seed mass and seed structure defined as endospermic and non-endospermic. This is presented alongside the locations of temperature minima per species which can be used to examine the extent to which different seed structures are associated with snow cover. We hope that the dataset can be used by others to demonstrate if certain seed structures and sizes are associated with snow cover, and if so, would they be negatively impacted by the loss of snow resulting from climate change.