Exploring the Role of Carbon Monoxide in Seed Physiology: Implications for Stress Tolerance and Practical Uses.

Carbon monoxide (CO) is recognized as a signaling molecule in plants, inducing various physiological responses. This article briefly examines the physiological functions of CO in seed biology and seedlings' responses to environmental stresses. The activity of heme oxygenase (HO), the main enzyme responsible for CO synthesis, is a key factor controlling CO levels in plant cells.

The Roles of RNA Modifications in Regulating Chloroplast Performance and Photosynthesis Efficiency.

The regulation of gene expression is crucial for maintaining cellular activities and responding to environmental stimuli. RNA molecules are central to this regulatory network, influencing transcription, post-transcriptional processing, and translation. Recent advancements have expanded our understanding of RNA modifications beyond the nucleus, highlighting their impact on chloroplast function and photosynthesis efficiency.

S2P2-the chloroplast-located intramembrane protease and its impact on the stoichiometry and functioning of the photosynthetic apparatus of .

S2P2 is a nuclear-encoded protease, potentially located in chloroplasts, which belongs to the zinc-containing, intramembrane, site-2 protease (S2P) family. In cells, most of the S2P proteases are located within the chloroplasts, where they play an important role in the development of chloroplasts, maintaining proper stoichiometric relations between polypeptides building photosynthetic complexes and influencing the sensitivity of plants to photoinhibitory conditions. Among the known chloroplast S2P proteases, S2P2 protease is one of the least known.

The role of EGY2 protease in response to high light stress.

In this study, we investigated the importance of one of the intramembrane proteases, EGY2, for the proper functioning of PSII under short-term high light stress conditions. EGY2 is a chloroplast intramembrane protease of the S2P family, whose absence in Arabidopsis thaliana affects PSII protein composition. The egy2 mutants exhibited a slower degradation of PsbA and decreased content of PsbC and PsbD.

Stress-related expression of the chloroplast EGY3 pseudoprotease and its possible impact on chloroplasts' proteome composition.

The EGY3 is a pseudoprotease, located in the thylakoid membrane, that shares homology with the family of site-2-proteases (S2P). Although S2P proteases are present in the cells of all living organisms, the EGY3 was found only in plant cells. The sequence of the pseudoprotease is highly conserved in the plant kingdom; however, little is known about its physiological importance.

Live Impedance Measurements and Time-lapse Microscopy Observations of Cellular Adhesion, Proliferation and Migration after Ionizing Radiation.

Background: Changes in the cellular behavior depend on environmental and intracellular interactions. Cancer treatments force the changes, first on the molecular level, but the main visible changes are macroscopic. During radiotherapy, cancer cell's adhesion, proliferation and migration should be well monitored.

UV radiation in HCT 116 cells influences intracellular H2O2 and glutathione levels, antioxidant expression, and protein glutathionylation.

UV radiation influences cellular levels of hydrogen peroxide (H2O2) and glutathione (GSH) and alters the expression of antioxidant genes in the human colorectal cancer cell line HCT116. In this study, cells were irradiated with UV light of different wavelength (A, B, or C). A surge in H2O2 concentration and total glutathione (level occurred 6 hours later.

The adipokine vaspin reduces apoptosis in human hepatocellular carcinoma (Hep-3B) cells, associated with lower levels of NO and superoxide anion.

Background: Among adipose-derived factors, adipocytokines play roles as hormones and signaling mediators for apoptotic pathway. Among of them, vaspin, regulates the metabolism of adipose tissue itself as an endocrine organ, and stimulates adipocytes to maturation, differentiation, etc. Damaged adipocytes, present in obesity and hepatocellular carcinoma (HCC) respond with over-production of inflammatory cytokines.

Arabidopsis thaliana egy2 mutants display altered expression level of genes encoding crucial photosystem II proteins.

EGY2 is a zinc-containing, intramembrane protease located in the thylakoid membrane. It is considered to be involved in the regulated intramembrane proteolysis - a mechanism leading to activation of membrane-anchored transcription factors through proteolytic cleavage, which causes them to be released from the membrane. The physiological functions of EGY2 in chloroplasts remains poorly understood.

Teaching about Water Relations in Plant Cells: An Uneasy Struggle.

University students often struggle to understand the role of water in plant cells. In particular, osmosis and plasmolysis appear to be challenging topics. This study attempted to identify student difficulties (including misconceptions) concerning osmosis and plasmolysis and examined to what extent the difficulties could be revised during a plant physiology course.

Excitation energy transfer and charge separation are affected in Arabidopsis thaliana mutants lacking light-harvesting chlorophyll a/b binding protein Lhcb3.

The composition of LHCII trimers as well as excitation energy transfer and charge separation in grana cores of Arabidopsis thaliana mutant lacking chlorophyll a/b binding protein Lhcb3 have been investigated and compared to those in wild-type plants. In grana cores of lhcb3 plants we observed increased amounts of Lhcb1 and Lhcb2 apoproteins per PSII core. The additional copies of Lhcb1 and Lhcb2 are expected to substitute for Lhcb3 in LHCII trimers M as well as in the LHCII "extra" pool, which was found to be modestly enlarged as a result of the absence of Lhcb3.

Monte Carlo simulations of excitation and electron transfer in grana membranes.

Time-resolved fluorescence measurements on grana membranes with instrumental response function of 3 ps reveal faster excitation dynamics (120 ps) than those reported previously. A possible reason for the faster decay may be a relatively low amount of "extra" LHCII trimers per reaction center of Photosystem II. Monte Carlo modeling of excitation dynamics in C2S2M2 form of PSII-LHCII supercomplexes has been performed using a coarse grained model of this complex, constituting a large majority of proteins in grana membranes.

The irradiance dependent transcriptional regulation of AtCLPB3 expression.

Transcript abundance analysis was applied to determine whether expression of genes coding for 50 principal constituents of chloroplast and mitochondria proteolytic machinery, i.e. isoforms of proteases and regulatory subunits of Clp and FtsH families as well as Deg group of chymotrypsin family are differentially expressed in response to acclimation to elevated irradiance.

Redox state of plastoquinone pool regulates expression of Arabidopsis thaliana genes in response to elevated irradiance.

DNA microarray technology was applied to gain insight into the role of the redox state of PQ pool as a retrograde factor mediating differential expression of Arabidopsis nuclear genes during the acclimation to changing irradiance. DNA microarray chips containing probes corresponding to 24,000 Arabidopsis nuclear genes were screened with cRNA samples prepared from leaves of plants exposed for 5 h to low irradiance (control) vs. medium, high and excessive irradiances (MI, HI and EI, respectively).

[Molecular responses of photosynthetic apparatus of plants to long term irradiance changes].

In response to long term (at least 1-3 h) irradiance changes the responses are elicited at the level of structure and function of photosynthetic apparatus of plants which are thought to be aimed to keep the balance between the level of excitation energy funneled to the reaction centers of the photosystems by energetic antennae and the utilization of this energy in the form of photosynthetic electron transfer and dark reactions. At high vs medium irradiances the rate of excitation energy transfer via LHCII is reduced while the rate of electron flow and photosynthetic dark reactions is increased. The reaction at LHCII level stems from the reduction of its pool per PSII reaction center and the regulatory events comprise changes in the expression of LHCII apoproteins and/or chi b biosynthesis.