Bioactive Compounds Produced by Endophytic Bacteria and Their Plant Hosts-An Insight into the World of Chosen Herbaceous Ruderal Plants in Central Europe.

The natural environment has been significantly impacted by human activity, urbanization, and industrialization, leading to changes in living organisms and their adaptation to harsh conditions. Species, including plants, adapt to these changes by creating mechanisms and modifications that allow them to survive in harsh environments. Also, endophytes, microorganisms that live inside plants, can support plant growth and defense mechanisms in these conditions by synthesizing antimicrobial secondary metabolites. What is more, endophytes produce bioactive metabolites, including alkaloids, amines, and peptides, which play a crucial role in the relationship between endophytes and their host organisms. Endophytes themselves benefit from this by creating a stable environment for their survival and development. The aim of this review is to gain insight into endophytic bioactive metabolites from chosen synanthropic ruderal plants. Industrial activities release pollutants like heavy metals, by-products, and waste, which challenge living organisms and require adaptation. Synanthropic plants, where endophytes are abundant, are particularly valuable for their bioactive compounds, which are used in agriculture and medicine. This review presents, among others, endophytes of herbaceous ruderal plants from central Europe-Chelidonium majus L., Urtica dioica L., Plantago lanceolata L., Matricaria chamomilla L., Equisetum arvense L., Oenothera biennis L., Silybum marianum L., and Mentha piperita L.

Endophytic bacteria isolated from Urtica dioica L.- preliminary screening for enzyme and polyphenols production.

Endophytes, especially those isolated from herbal plants, may act as a reservoir of a variety of secondary metabolites exhibiting biological activity. Some endophytes express the ability to produce the same bioactive compounds as their plant hosts, making them a more sustainable industrial supply of these substances. Urtica dioica L. (common stinging nettle) is a synanthropic plant that is widely used in herbal medicine due to the diversity of bioactive chemicals it contains, e.g., polyphenols, which demonstrate anti-inflammatory, antioxidant, and anti-cancerous capabilities. This study aimed at isolating endophytic bacteria from stinging nettles for their bioactive compounds. The endophytic isolates were identified by both biochemical and molecular methods (16S rRNA) and investigated for enzymes, biosurfactants, and polyphenols production. Each of the isolated bacterial strains was capable of producing biosurfactants and polyphenols. However, three of the isolated endophytes, identified as two strains of Bacillus cereus and one strain of Bacillus mycoides, possessed the greatest capacity to produce biosurfactants and polyphenols. The derivatized extracts from culture liquid showed the 1.633 mol l-1 (9.691 mg l-1) concentration of polyphenol compounds. Therefore, the present study signifies that endophytic B. cereus and B. mycoides isolated from Urtica dioica L. could be a potential source of biosurfactants and polyphenols. However, further study is required to understand the mechanism of the process and achieve efficient polyphenol production by endophytic bacteria.

Plants as the Extended Phenotype of Endophytes-The Actual Source of Bioactive Compounds.

For thousands of years, plants have been used for their medicinal properties. The industrial production of plant-beneficial compounds is facing many drawbacks, such as seasonal dependence and troublesome extraction and purification processes, which have led to many species being on the edge of extinction. As the demand for compounds applicable to, e.g., cancer treatment, is still growing, there is a need to develop sustainable production processes. The industrial potential of the endophytic microorganisms residing within plant tissues is undeniable, as they are often able to produce, in vitro, similar to or even the same compounds as their hosts. The peculiar conditions of the endophytic lifestyle raise questions about the molecular background of the biosynthesis of these bioactive compounds in planta, and the actual producer, whether it is the plant itself or its residents. Extending this knowledge is crucial to overcoming the current limitations in the implementation of endophytes for larger-scale production. In this review, we focus on the possible routes of the synthesis of host-specific compounds in planta by their endophytes.

Attentional Prioritization of Complex, Naturalistic Stimuli Maintained in Working-Memory-A Dot-Probe Event-Related Potentials Study.

Recent studies suggest that a stimulus actively maintained in working memory (WM) automatically captures visual attention when subsequently perceived. Such a WM-based guidance effect has been consistently observed for stimuli defined by simple features, such as color or orientation, but studies using more complex stimuli provided inconclusive results. Therefore, we investigated whether the WM-based guidance effect occurs also for naturalistic stimuli, whose identity is defined by multiple features and relations among them, specifically for faces and houses. The experiment consisted of multiple blocks in which participants (N = 28) either memorized or merely saw (WM or exposure condition, respectively) a template stimulus and then performed several dot-probe trials, with pairs of stimuli (template and control) presented laterally as distractors and followed by a target-asterisk. Analysis of reaction-times (RT) in the dot-probe task shows that memorized stimuli were prioritized by attention and points toward attention-hold, rather than capture, as a mechanism of attentional prioritization. Consistent with this interpretation, memorized items did not evoke a lateralized N2pc ERP component, thought to indicate attention shifts. However, in an exploratory ERP analysis we found evidence for a very early (100-200 ms post-stimulus) prioritization specific to the memorized faces, which is in line with the sensory recruitment theory of WM. In conclusion, our data provide evidence that complex stimuli are prioritized by attention when maintained in WM, and that the mechanism of such prioritization is based on a prolonged hold of spatial attention.

The role of individual differences in attentional blink phenomenon and real-time-strategy game proficiency.

The impact of action videogame playing on cognitive functioning is the subject of debate among scientists, with many studies showing superior performance of players relative to non-players on a number of cognitive tasks. Moreover, the exact role of individual differences in the observed effects is still largely unknown. In our Event-Related Potential (ERP) study we investigated whether training in a Real Time Strategy (RTS) video game StarCraft II can influence the ability to deploy visual attention measured by the Attentional Blink (AB) task. We also asked whether individual differences in a psychophysiological response in the AB task predict the effectiveness of the video game training. Forty-three participants (non-players) were recruited to the experiment. Participants were randomly assigned to either experimental (Variable environment) or active control (Fixed environment) group, which differed in the type of training received. Training consisted of 30 h of playing the StarCraft II game. Participants took part in two EEG sessions (pre- and post-training) during which they performed the AB task. Our results indicate that both groups improved their performance in the AB task in the post-training session. What is more, in the experimental group the strength of the amplitude of the P300 ERP component (which is related to a conscious visual perception) in the pre training session appeared to be predictive of the level of achievement in the game. In the case of the active control group in-game behaviour appeared to be predictive of a training-related improvement in the AB task. Our results suggest that differences in the neurophysiological response might be treated as a marker of future success in video game acquisition, especially in a more demanding game environment.