Evidence for the Widespread Occurrence of Bacteria Implicated in Acute Oak Decline from Incidental Genetic Sampling

Acute Oak Decline (AOD) is complex syndrome affecting Britain’s keystone native oak species, (Quercus robur L. and Q. petraea L. (Matt.) Liebl.), in some cases causing mortality within five years of symptom development. The most distinguishable symptom is weeping stem lesions, from which four species of bacteria have been isolated: Brenneria goodwinii, Gibbsiella quercinecans, Lonsdalea britannica and Rahnella victoriana. We do not yet know where else these bacteria exist, and little is known about the relationship of the wider oak leaf microbiome (phyllosphere) to acute oak decline. Here we investigate whether incidental evidence from a large oak genome re-sequencing dataset could be used to detect these bacteria in oak foliage, and whether bacterial incidence co-varied with AOD status or location. Oak leaves and buds were sampled from 421 trees at five sites in England. Whole genomic DNA from these samples was shot-gun sequenced with short reads. Non-oak reads were extracted from these data and queried to microbial databases. Reads uniquely matching AOD-associated bacterial genomes were found to be present on trees from all five sites and included trees with active lesions, trees with historic lesions and trees without AOD symptoms. The abundance of the AOD-associated bacteria did not differ between tree health categories but did differ among sites. We conclude that the AOD-associated bacteria may be members of the normal oak microbiome, whose presence on a tree is not sufficient to cause AOD symptoms.

ANALYSIS OF THE ECOLOGICAL STATE OF THE AIR ENVIRONMENT IN THE CITY OF KINESHMA IN THE IVANOVSK REGION BY THE METHOD OF FLUCTUATING ASYMMETRY

Morphological changes occur in the leaves of trees under the influence of various air pollutants. Recording and assessing these changes reflects the state of the environment. The aim of the study was to assess the level of air pollution in the city of Kineshma, Ivanovo region, using the bioindication method. The technique of morphometry of pedunculate oak leaves and calculation of the index of fluctuating asymmetry were used. In all points of the city, a high asymmetry of oak leaf blades was noted, which indicates a critical level of atmospheric pollution. Ecotoxicants contained in emissions from enterprises and vehicles significantly violate the bilateral symmetry of oak leaf blades.

Evidence for the Widespread Occurrence of Bacteria Implicated in Acute Oak Decline from Incidental Genetic Sampling

Acute Oak Decline (AOD) is complex syndrome affecting Britain’s keystone native oak species, (Quercus robur L. and Q. petraea L. (Matt.) Liebl.), in some cases causing mortality within five years of symptom development. The most distinguishable symptom is weeping stem lesions, from which four species of bacteria have been isolated: Brenneria goodwinii, Gibbsiella quercinecans, Lonsdalea britannica and Rahnella victoriana. We do not yet know where else these bacteria exist, and little is known about the relationship of the wider oak leaf microbiome (phyllosphere) to acute oak decline. Here we investigate whether incidental evidence from a large oak genome re-sequencing dataset could be used to detect these bacteria in oak foliage, and whether bacterial incidence co-varied with AOD status or location. Oak leaves and buds were sampled from 421 trees at five sites in England. Whole genomic DNA from these samples was shot-gun sequenced with short reads. Non-oak reads were extracted from these data and queried to microbial databases. Reads uniquely matching AOD-associated bacterial genomes were found to be present on trees from all five sites and included trees with active lesions, trees with historic lesions and trees without AOD symptoms. The abundance of the AOD-associated bacteria did not differ between tree health categories but did differ among sites. We conclude that the AOD-associated bacteria may be members of the normal oak microbiome, whose presence on a tree is not sufficient to cause AOD symptoms.

Anatomy and Ultrastructure of Galls Induced by Neuroterus quercusbaccarum (Hymenoptera: Cynipidae) on Oak Leaves (Quercus robur)

The structure and ultrastructure of two developmental stages of the spangle gall induced by Neuroterus quercusbaccarum (Hymenoptera, Cynipidae) were investigated using light microscopy (LM), fluorescence microscopy (FM), and transmission (TEM) and scanning (SEM) electron microscopy. The general design of the gall structure was typical of Cynipidae, but some structural features distinguished the spangle gall. Previously undescribed, characteristic multicellular epidermal protuberances with large openings were observed in autumn on the surface of galls. These may facilitate the gas exchange between the atmosphere and the inside of the gall, thus assisting larval respiration. The larval chamber is surrounded by both a sclerenchymatous capsule and numerous cells containing calcium oxalate crystals that may both serve as protective barriers. In young galls, the nutritive tissue is a wall-less protoplasmic mass, potentially easily accessible to young larvae with delicate mandibles. Cell walls only develop at a later stage. The nutritive tissue was found to be rich in proteins and lipids, but starch grains were not observed. Cellular topology suggests that spangle galls grow by anticlinal division of marginal epidermal cells and periclinal division of subepidermal cells. Cellular proliferation (hyperplasia) also occurs in the leaf tissue near the connection with the gall peduncle, which eventually lignifies.

The Symbolism of Oak Leaves in Dostoevsky’s Notebooks (Drafts) to Crime and Punishment (with illustrations)

The article offers a new interpretation of the various expressions of the motif or sign of oak leaves, contained in the manuscript drafts of the novel Crime and Punishment. The expressions of the motif are decoded in the style of 3D letters, pointing to the key words of the third draft of the novel: “Dostoevsky”, “Journal”, “Routine”. These signs, which are part of Dostoevsky’s ideographic language, belong to the period of work on the novel from October to December 1865. It is the period in which the hero’s ideology was radically transformed, and the philanthropic motivation of the murders (to help the mother and the sister) was substituted by the “Napoleonic idea” (“am I a trembling worm or do I have the right”). The examination of these signs in conjunction with the writer’s notes contiguous with them, leads to the inference that these signs are genetically connected with the heraldry of the Dostoevsky clan, as well as with the symbolism of the 19th century “mundir” (uniform) attributions: the oak leaves were embroidery adorning a general’s “mundir”, and were a sign of recognition “for outstanding service”. Napoleon’s uniform, at the time of the Battle of Marengo, also had oak leaves embroidery; the battle is mentioned twice by Dostoevsky in the course of work on Crime and Punishment.

Oak leaf (Quercus spp.) intoxication in a sheep

A twenty-year-old ewe presented with acute lateral decubitus, tremor and dyspnea, followed by death. Post-mortem examination revealed a large amount of oak leaves in the rumen, reticulum and omasum. The duodenum had a focal hemorrhagic content and multifocal hemorrhages were present in several organs. Histopathological examination of the kidneys showed characteristic lesions of oak intoxication, such as intratubular hemorrhage, tubular degeneration and necrosis. This case report illustrates the importance to include oak intoxication in the differential diagnosis of acute death in sheep and the value of post-mortem and histopathological examination.

The state of the adaptive potential of Quercus robur L. in field-protective forest belts based on the study of substances of secondary metabolism

The paper studies various groups of substances of secondary metabolism of phenolic nature in the leaves of model trees of English oak growing in the field-protective forest belts of the agroforestry complex Kamennaya Steppe. A physiological and biochemical analysis was carried out on samples of oak leaves from each tree in two stages - in the first decade of June and in early August. From each model tree 4-6 shoots of the lower tier of the southern exposure were selected. Significant biochemical diversity of the control and experimental groups of model oak trees was revealed. It is shown that the most significant fluctuations in the level of phenolic substances occur at the beginning of the growing season and then their content is stabilized. The informativeness of biochemical monitoring studies in the complex assessment of the current state of oak stands was confirmed. It is proved that the content of substances of secondary metabolism of phenolic nature and their combination can serve as a criterion of potential energy efficiency.