Physiological Biochemical Changes Research Articles

The Effecting Mechanisms of 100 nm Sized Polystyrene Nanoplastics on the Typical Coastal Alexandrium tamarense.

Due to the increase in nanoplastics (NPs) abundance in aquatic environments, their effects on phytoplankton have aroused large research attention. In this study, 100 nm sized polystyrene NPs were chosen to investigate their effecting performance and mechanisms on a typical dinoflagellates Alexandrium tamarense. The results indicated the population growth and photosynthetic efficiencies of A. tamarense were significantly inhibited by NPs exposure, as well as the increase in cellular total carotenoids and paralytic shellfish toxins (PSTs). Meanwhile, the cellar ROS levels increased, corresponding to the increased activities or contents of multiple antioxidant components, including SOD, CAT, GPX, GR, GSH and GSSG. The transcriptional results support the physiological-biochemical results and further revealed the down-regulation of genes encoding the light reaction centers (PSI and PSII) and up-regulation of genes encoding the antioxidant components. Up-regulation of genes encoding key enzymes of the Calvin cycle and glycolytic pathway together with the TCA cycle could accelerate organic carbon and ATP production for A. tamarense cells resistant to NPs stress. Finally, more Glu and acetyl-CoA produced by the enhanced GSH cycle and the glycolytic pathway, respectively, accompanied by the up-regulation of Glu and Arg biosynthesis genes supported the increase in the PST contents under NPs exposure. This study established a data set involving physiological-biochemical changes and gene information about marine dinoflagellates responding to NPs, providing a data basis for further evaluating the ecological risk of NPs in marine environments.

Physiological and Biochemical Background of Deacclimation in Plants, with Special Attention Being Paid to Crops: A Minireview

Global climate change, which is connected to global warming and changes in weather patterns, affects various parts of the environment, including the growth/development of plants. Generally, a number of plant species are capable of acquiring tolerance to frost after exposure to cold (in the cold-acclimation/cold-hardening process). In the last few decades, there have been more and more frequent periods of higher temperatures—warm periods that, e.g., break down the process of cold acclimation. This generates deacclimation, which could stimulate growth and lower frost tolerance in plants. Generally, deacclimation causes the reversal of changes induced by cold acclimation (i.e., in concentration of sugars, accumulation of protective proteins, or hormonal homeostasis). Unlike cold acclimation, the phenomenon of deacclimation has been less studied. The aim of this article was (1) to briefly describe the problem of deacclimation, with more attention being paid to its significance for economically important winter crop species, (2) to review and characterize the physiological-biochemical changes that are induced in plants by deacclimation, and (3) to discuss the possibilities of detecting deacclimation earlier in order to counteract its effects on crops.

Changes in the sugar-acid ratio in apple fruits depending on the applied storage technology

Physiological-biochemical changes that occur during the post-harvest period lead to the deterioration of the quality of agricultural products. The main biochemical indices of fruit quality, which determine their taste and consistency, are sugars and organic acids. As the apples ripen, the total amount of sugars increases and the acidity decreases. The taste of the fruits is determined not only by the absolute content of organic acids and sugars, but mainly by their ratio in the fruit. The fruits treated post-harvest with the Fitomag preparation were characterized at the time of release from storage by a more harmonious taste, compared to the control fruits. The sugar-acid ratio can be used as a diagnostic indicator of quality, by monitoring the biochemical content of fruits in storage.

Influence of silver nitrate and copper sulfate on somatic embryogenesis, shoot morphogenesis, multiplication, and associated physiological biochemical changes in Gladiolus hybridus L.

Influence of silver nitrate and copper sulfate on somatic embryogenesis, shoot morphogenesis, multiplication, and associated physiological biochemical changes in Gladiolus hybridus L.

The molecular response mechanisms of a diatom Thalassiosira pseudonana to the toxicity of BDE-47 based on whole transcriptome analysis

Polybrominated diphenyl ethers (PBDEs) are ubiquitously distributed persistent organic pollutants (POPs) in marine environments. Phytoplankton are the entrance of PBDEs entering to biotic environments from abiotic environments, while the responding mechanisms of phytoplankton to PBDEs have not been full established. Therefore, we chose the model diatom Thalassiosira pseudonana in this study, by integrating whole transcriptome analysis with physiological-biochemical data, to reveal the molecular responding mechanisms of T. pseudonana to the toxicity of BDE-47. Our results indicated the changes of genes expressions correlated to the physiological-biochemical changes, and there were multiple molecular mechanisms of T. pseudonana responding to the toxicity of BDE-47: Gene expressions evidence explained the suppression of light reaction and proved the occurrence of cellular oxidative stress; In the meanwhile, up-regulations of genes in pathways involving carbon metabolisms happened, including the Calvin cycle, glycolysis, TCA cycle, fatty acid synthesis, and triacylglycerol synthesis; Lastly, DNA damage was found and three outcome including DNA repair, cell cycle arrest and programmed cell death (PCD) happened, which could finally inhibit the cell division and population growth of T. pseudonana. This study presented the most complete molecular responding mechanisms of phytoplankton cells to PBDEs, and provided valuable information of various PBDEs-sensitive genes with multiple functions for further research involving organic pollutants and phytoplankton.

Structural and functional reorganization of the photosynthetic apparatus in adaptation to cold of wheat plants

In seedlings of a cold-resistant wheat variety, the dynamics was studied of the main structural-functional parameters of the photosynthetic apparatus (PSA) and of cold resistance of leaf cells in low-temperature plant adaptation. It has been established that a complex of structural-functional PSA changes takes place in seedling leaves under the influence of cold. As a result, as early as in the first hours of hardening, the formation of chloroplasts begins to occur in mesophyll cells of larger sizes and with a thylakoid system of the “sun type.” Owing to structural and functional readjustment (a change of content of pigments, stabilization of pigment-protein complexes, and enhancement of nonphotochemical quenching of excess energy) in the process of cold adaptation, the rate of photosynthesis stabilizes. It is suggested that the observed structural-functional PSA rearrangement is a necessary condition for formation of increased cold resistance of leaf cells; this, alongside with other physiological-biochemical changes occurring in parallel in cells and tissues of the plants, provides their survival under conditions of low temperatures.

Dynamics of glucocorticoids in the ontogenesis of freshwater crawfish Astacus leptodactylus Esch

Dynamics of changes in glucocorticoid (hydrocortisone and corticosterone) levels was studied in the ontogenesis of freshwater crawfish Astacus Leptodactylus Esch. It was shown that steroid concentrations increase during the embryogenesis period. Decrease in the glucocorticoid levels during postembryonic development is most probably related to the stabilization of young fish growth and the attainment of hormone levels typical for adult individuals. The correlation ofglucocorticoid levels with physiological-biochemical changes at different stages of ontogenesis indicates that these steroids play an essential role in the regulation of freshwater crawfish vital functions.

Acid phosphatase activity in the intestine and caeca of bluegill, exposed to methyl mercuric chloride.

The toxic effects of mercury on fish can be measured accurately by studying the enzymes and other biochemical indicators. The gross organismic changes in fish due to mercury toxicity occur only after significant damage to the internal tissue or physiological-biochemical changes in the tissue. The intestine has contact with the external environment via food. Therefore, any significant alteration in the environment may induce some changes in the structure and function of the digestive tract. An attempt has been made to measure the changes in acid phosphatase activity in different regions of intestine and intestinal diverticulae of bluegill fish as these enzymes are highly sensitive to methyl mercury.

A GRAPE VARIETIES RESISTANCE TO LOW WINTER TEMPERATURES

In the conditions of frequently repeated in recent years, temperature fluctuations in the Anao-Taman zone of the Krasnodar region, where the main areas of grape plantings are concentrated, the resistance issues of grapes to low temperatures of the winter period are particularly relevant, since sharp differences in the air temperature in the autumn-winter period contribute to the decrease in winter resistance Grape vines. The article presents the results of the assessment of physiological biochemical changes, which are a fundamental adaptive reaction of plants associated with the frost resistance of grapes of various ecological and geographical origin: Dostoyny, Krasnostop, Kristall, Vostorg, Aligote, Zarif. As a result of research in grape varieties, Krasnostop, Crystal, Vostorg was revealed to maximize kidney hydrogen decreased (by 11.7-15.3%) and increased accumulation of water-soluble sugars (at 2.67-3.29 times) in comparison with other studied varieties, What speaks of their larger resistance to low temperatures. The variety of the Vostorg was discovered an increase in the content of proline by 40.5 times, indicating its active participation in the formation of a protective response to low temperatures. In all studied grape varieties have a closer connection between the kidney hydrogen and the content of soluble sugars in the core than with the content of the proline. Of all varieties, the waters of the grape vines, the content of soluble sugars and proline, the varieties of the Krasnostop, Crystal, Vostorg are allocated as the most resistant to low temperatures in the conditions of the Anao Taman zone of the Krasnodar Territory, which makes it possible to conclude the possibility of their use in the selection process in quality sources of frost resistance.