Population structure of geographical cultures of European spruce in the estimates of the pigment composition of needles

Изучали содержание и соотношение пластидных пигментов в хвое представителей разных популяций ели европейской, введенных в состав географических культур на территории Нижегородской области. Применяли спектрофотометрический метод выявления количественных оценок пигментного состава листового аппарата с обеспечением принципа единственного логического различия и основных требований к организации опыта. Проведены натурные обследования насаждений и лабораторные анализы биологических проб. Выявлены различия между представителями удаленных друг от друга популяций ели европейской при их совместном выращивании в составе географических культур по комплексу показателей пигментного состава однолетней хвои. Наибольшее содержание хлорофилла-а (3,25±0,06 мг/г) отмечено у семенного потомства популяций из Псковской области, что в 1,26 раза превосходит соответствующий минимум (2,57±0,04 мг/г), зафиксированный у представителей популяций из Калининградской области. Зафиксированы сходные масштабы соотношения оценок содержания хлорофилла-b, притом что максимальные значения (1,37±0,05 мг/г и 1,37±0,06 мг/г) наблюдались у происхождений из Костромской и Карельской областей, а минимальные (1,07±0,03 мг/г и 1,09±0,03 мг/г) – у представителей популяций из Архангельской и Калининградской областей. Подтверждена существенность различий между популяциями ели европейской по всем рассматриваемым показателям пигментного состава. Обнаружено сходство в сложении трех группировок популяций, возникших при выполнении факторного и кластерного анализа. Коэффициенты плотности кластера (средняя евклидова дистанция его сложения) каждой их них составили: 6,258 единиц евклидовой дистанции (у первой); 4,374 ед. (у второй); 7,818 ед. (у третьей) и 6,150 ед. (общая средняя дистанция). Среднее межкластерное расстояние при этом достигло 20,414 ед., что принципиально больше величин внутрикластерных дистанций и позволяет признать корректным выделение кластеров. Обоснован устойчивый характер соотношения популяций ели европейской, имеющих различное географическое происхождение, по пигментному составу хвои. The content and ratio of plastid pigments in the conifers of representatives of different populations of Norway spruce introduced into the geographic test-cultures in the Nizhny Novgorod region were studied. A spectrophotometric method was used to identify quantitative estimates of the pigment composition of the leaf apparatus, ensuring the principle of a single logical difference and the basic requirements for the organization of the experiment. Field surveys of plantings and laboratory analyses of biological samples were carried out. The differences between representatives of Norway spruce populations that are remote from each other were revealed when they were grown together as part of geographical crops according to the complex of indicators of the pigment composition of annual needles. The highest content of chlorophyll-a (3.25±0.06 mg/g) was observed in the seed offspring of populations from the Pskov region, which is 1.26 times higher than the corresponding minimum (2.57±0.04 mg/g) recorded in representatives of populations from the Kaliningrad region. Similar scales of the ratio of estimates of the content of chlorophyll-b were recorded, despite the fact that the maximum values (1.37±0.05 mg/g and 1.37±0.06 mg/g) were observed in the origin from the Kostroma and Karelian regions, and the minimum values (1.07±0.03 mg/g and 1.09±0.03 mg/g) were observed in representatives of populations from the Arkhangelsk and Kaliningrad regions. The significance of differences between the populations of Norway spruce in all the considered indicators of pigment composition was confirmed. A similarity was found in the addition of three groups of populations that arose during factor and cluster analysis. The cluster density coefficients (the average Euclidean distance of its addition) of each of them were: 6,258 units of the Euclidean distance (for the first one); 4,374 units. (in the second); 7,818 units. (at the third) and 6,150 units. (total average distance). The average inter-cluster distance at the same time reached 20,414 units, which is fundamentally greater than the values of intra-cluster distances and allows us to recognize the correct allocation of clusters. The stable nature of the ratio of populations of Norway spruce with different geographical origin, according to the pigment composition of needles, is justified.

Allosteric Modulation of NMDARs Reverses Patients' Autoantibody Effects in Mice

Background and ObjectivesTo demonstrate that an analog (SGE-301) of a brain-derived cholesterol metabolite, 24(S)-hydroxycholesterol, which is a selective positive allosteric modulator (PAM) of NMDA receptors (NMDARs), is able to reverse the memory and synaptic alterations caused by CSF from patients with anti-NMDAR encephalitis in an animal model of passive transfer of antibodies.MethodsFour groups of mice received (days 1–14) patients' or controls' CSF via osmotic pumps connected to the cerebroventricular system and from day 11 were treated with daily subcutaneous injections of SGE-301 or vehicle (no drug). Visuospatial memory, locomotor activity (LA), synaptic NMDAR cluster density, hippocampal long-term potentiation (LTP), and paired-pulse facilitation (PPF) were assessed on days 10, 13, 18, and 26 using reported techniques.ResultsOn day 10, mice infused with patients' CSF, but not controls' CSF, presented a significant visuospatial memory deficit, reduction of NMDAR clusters, and impairment of LTP, whereas LA and PPF were unaffected. These alterations persisted until day 18, the time of maximal deficits in this model. In contrast, mice that received patients' CSF but from day 11 were treated with SGE-301 showed memory recovery (day 13), and on day 18, all paradigms (memory, NMDAR clusters, and LTP) had reversed to values similar to those of controls. On day 26, no differences were observed among experimental groups.DiscussionAn oxysterol biology-based PAM of NMDARs is able to reverse the synaptic and memory deficits caused by CSF from patients with anti-NMDAR encephalitis. These findings suggest a novel adjuvant treatment approach that deserves future clinical evaluation.

Nanoscale Organisation of Ryanodine Receptors and Junctophilin-2 in the Failing Human Heart

The disrupted organisation of the ryanodine receptors (RyR) and junctophilin (JPH) is thought to underpin the transverse tubule (t-tubule) remodelling in a failing heart. Here, we assessed the nanoscale organisation of these two key proteins in the failing human heart. Recently, an advanced feature of the t-tubule remodelling identified large flattened t-tubules called t-sheets, that were several microns wide. Previously, we reported that in the failing heart, the dilated t-tubules up to ~1 μm wide had increased collagen, and we hypothesised that the t-sheets would also be associated with collagen deposits. Direct stochastic optical reconstruction microscopy (dSTORM), confocal microscopy, and western blotting were used to evaluate the cellular distribution of excitation-contraction structures in the cardiac myocytes from patients with idiopathic dilated cardiomyopathy (IDCM) compared to myocytes from the non-failing (NF) human heart. The dSTORM imaging of RyR and JPH found no difference in the colocalisation between IDCM and NF myocytes, but there was a higher colocalisation at the t-tubule and sarcolemma compared to the corbular regions. Western blots revealed no change in the JPH expression but did identify a ~50% downregulation of RyR (p = 0.02). The dSTORM imaging revealed a trend for the smaller t-tubular RyR clusters (~24%) and reduced the t-tubular RyR cluster density (~35%) that resulted in a 50% reduction of t-tubular RyR tetramers in the IDCM myocytes (p < 0.01). Confocal microscopy identified the t-sheets in all the IDCM hearts examined and found that they are associated with the reticular collagen fibres within the lumen. However, the size and density of the RyR clusters were similar in the myocyte regions associated with t-sheets and t-tubules. T-tubule remodelling is associated with a reduced RyR expression that may contribute to the reduced excitation-contraction coupling in the failing human heart.

Exploring the step function distribution of the threshold fraction of adopted neighbors versus minimum fraction of nodes as initial adopters to assess the cascade blocking intra-cluster density of complex real-world networks

We first propose a binary search algorithm to determine the minimum fraction of nodes in a network to be used as initial adopters ($$f_{IA}^{\min }$$ f IA min ) for a particular threshold fraction (q) of adopted neighbors (related to the cascade capacity of the network) leading to a complete information cascade. We observe the q versus $$f_{IA}^{\min }$$ f IA min distribution for several complex real-world networks to exhibit a step function pattern wherein there is an abrupt increase in $$f_{IA}^{\min }$$ f IA min beyond a certain value of q (qstep); the $$f_{IA}^{\min }$$ f IA min values at qstep and the next measurable value of q are represented as $$\underline{{f_{IA}^{\min } }}$$ f IA min ̲ and $$\overline{{f_{IA}^{\min } }}$$ f IA min ¯ respectively. The difference $$\overline{{f_{IA}^{\min } }} - \underline{{f_{IA}^{\min } }}$$ f IA min ¯ - f IA min ̲ is observed to be significantly high (a median of 0.44 for a suite of 40 real-world networks studied in this paper) such that we claim the 1 − qstep value (we propose to refer 1 − qstep as the Cascade Blocking Index, CBI) for a network could be perceived as a measure of the intra-cluster density of the blocking cluster of the network that cannot be penetrated without including an appreciable number of nodes from the cluster to the set of initial adopters (justifying a relatively larger $$\overline{{f_{IA}^{\min } }}$$ f IA min ¯ value).