The induction of pyrenoid synthesis by hyperoxia and its implications for the natural diversity of photosynthetic responses in Chlamydomonas

In algae, it is well established that the pyrenoid, a component of the carbon-concentrating mechanism (CCM), is essential for efficient photosynthesis at low CO2. However, the signal that triggers the formation of the pyrenoid has remained elusive. Here, we show that, in Chlamydomonas reinhardtii, the pyrenoid is strongly induced by hyperoxia, even at high CO2 or bicarbonate levels. These results suggest that the pyrenoid can be induced by a common product of photosynthesis specific to low CO2 or hyperoxia. Consistent with this view, the photorespiratory by-product, H2O2, induced the pyrenoid, suggesting that it acts as a signal. Finally, we show evidence for linkages between genetic variations in hyperoxia tolerance, H2O2 signaling, and pyrenoid morphologies.

Geodiversity Assessment as a First Step in Designating Areas of Geotourism Potential. Case Study: Western Carpathians

Geodiversity is the natural diversity of features of geological structure, relief, and soil cover, including the relationships between these features, their properties, and their impact on other elements of the natural and cultural environment. It is described and analyzed using various types of quantitative, qualitative, or quantitative–qualitative methods. The concept of a geodiversity map presented in this article belongs to the third of these groups of methods. Despite the use of optimization methods in the form of a hexagon grid or the analytic hierarchy process calculator, it still remains partially subjective. The use of this method to calculate the geodiversity of an entire province (the Western Carpathians) gives a general view of the natural diversity of this area and allows regions to be selected for more detailed analyses or comparisons to be made between them. The geodiversity map is also a very good background on which to illustrate geotourist potential, which is expressed in terms of the number and distribution of geosites. However, in the case of the Western Carpathians, these two variables do not correlate with each other.

WASTE MANAGEMENT PROJECTIONS IN BULGARIA

Waste management is among the priority areas in the policy of Bulgaria, as part of the EU. Improving the environment by reducing landfilled waste, achieving balance and sustainability in different regions of our country, priority orientation to products from biodegradable household waste, effective reduction of greenhouse gas emissions, improving the condition of soils in Bulgaria, and preserving natural diversity are among the key objectives. Bulgaria's developed National Waste Plan until 2028 is a serious query to find ways to solve the problem of garbage in the country and create conditions for a successful transition to a circular economy. The purpose of the report is to analyze the costs of waste management in Bulgaria for the period 2015-2020 and to characterize the National Plan for Waste Management in Bulgaria until 2028.

2′O-Ribose Methylation of Ribosomal RNAs: Natural Diversity in Living Organisms, Biological Processes, and Diseases

Recent findings suggest that ribosomes, the translational machineries, can display a distinct composition depending on physio-pathological contexts. Thanks to outstanding technological breakthroughs, many studies have reported that variations of rRNA modifications, and more particularly the most abundant rRNA chemical modification, the rRNA 2′O-ribose methylation (2′Ome), intrinsically occur in many organisms. In the last 5 years, accumulating reports have illustrated that rRNA 2′Ome varies in human cell lines but also in living organisms (yeast, plant, zebrafish, mouse, human) during development and diseases. These rRNA 2′Ome variations occur either within a single cell line, organ, or patient’s sample (i.e., intra-variability) or between at least two biological conditions (i.e., inter-variability). Thus, the ribosomes can tolerate the absence of 2′Ome at some specific positions. These observations question whether variations in rRNA 2′Ome could provide ribosomes with particular translational regulatory activities and functional specializations. Here, we compile recent studies supporting the heterogeneity of ribosome composition at rRNA 2′Ome level and provide an overview of the natural diversity in rRNA 2′Ome that has been reported up to now throughout the kingdom of life. Moreover, we discuss the little evidence that suggests that variations of rRNA 2′Ome can effectively impact the ribosome activity and contribute to the etiology of some human diseases.

Cation and Anion Channelrhodopsins: Sequence Motifs and Taxonomic Distribution

Channelrhodopsins are widely used in neuroscience and cardiology as research tools and are considered prospective therapeutics, but their natural diversity and mechanisms remain poorly characterized. Genomic and metagenomic sequencing projects are producing an ever-increasing wealth of data, whereas biophysical characterization of the encoded proteins lags behind.

Coarse-graining ecological dynamics in the face of unknown microscopic details

Any description of an ecosystem necessarily ignores some details of the underlying diversity. What predictions can be robust to such omissions? Here, building on the theoretical framework of resource competition, we introduce an eco-evolutionary model that allows organisms to be described at an arbitrary, potentially infinite, level of detail, enabling us to formally study the hierarchy of possible coarse-grained descriptions. Within this model, we demonstrate that a coarse-graining scheme may enable ecological predictions despite grouping together functionally diverse strains. However, this requires two conditions: the strains we study must remain in a diverse ecological context, and this diversity must be derived from a sufficiently similar environment. Our model suggests that studying individual strains of a species away from their natural eco-evolutionary context may eliminate the very reasons that make a species-level characterization an adequate coarse-graining of the natural diversity.