Pigment System Research Articles

Uneven Influx of European-Specific Alleles of SLC45A2, SLC24A5, TYRP1, DRD2, EDAR, and OCA2 Genes into the Gene Pool of the Koryaks

The distribution of alleles highly specific to Europeans in the Koryak gene pool, which formed as a result of intensive interethnic admixture in the Northern Priokhotie, characterized by the prevailing genetic contribution from males of Eastern European origin, was analyzed. The loci rs16891982 (SLC45A2 gene), rs1426654 (SLC24A5 gene), rs1408799 (TYRP1 gene), rs1076563 (DRD2 gene), rs3827760 (EDAR gene), and rs1448485 (OCA2 gene), which are mainly associated with the pigmentation system, were selected for analysis. High heterogeneity was found in the frequency of European-specific alleles, ranging from 1.4% for the variant rs1076563-C of the DRD2 gene to 14.7% for the variant rs1426654-A of the SLC24A5 gene. The reasons for the uneven influx of European-specific alleles into the Koryak gene pool are discussed. It is possible that the formation of genetic structure of modern Koryaks under intensive interethnic admixture was accompanied by the influence of natural selection on some parts of the genome.

Extended perturbative approach including Redfield and Förster limits for qualitative analysis of exciton dynamics in any photosynthetic light harvesting and reaction center

According to many reports, the various structures of photosynthetic light-harvesting/reaction-center complexes and their molecular-dynamics simulations necessitate a numerically efficient and quality-conserved theory of excitation energy transfer and exciton relaxation in large pigment systems. Although exciton dynamics depend on various parameters, such as exciton coupling strength, exciton–phonon coupling, site energy values for each pigment, and temperature, classifying the transition mechanism for any Hamiltonian into perturbatively delocalized or localized theories is challenging. In this study, perturbative quantum master equations of a reduced density matrix for any orthogonal transformation similar to the coherent modified Redfield theory are derived. Our approach qualitatively conserves the dynamics of relevant perturbative approximations in each limiting case. As an application, any orthogonal transformation of a relevant system is optimized using the average of the square of interactions between orthogonal state transitions. The numerical results for two pigment systems are compared with the limiting formalisms of the modified Redfield and Förster theory.

Diversity analysis of cyanobacterial flora from the Tatapani Hot Spring of Chhattisgarh and exploration of their industrially as well as environmentally valuable properties

The present study investigates the cyanobacterial diversity of Tatapani hot spring, Chhattisgarh, India, using a polyphasic approach, their pigment system, biofuel properties and ability to bioremediate emerging pollutant triclosan. While the microscopic analyses of the natural samples reflected high cyanobacterial diversity with all morpho-forms, physicochemical studies revealed temperature being the major factor affecting the cyanobacterial distribution in the hot spring. Among the 22 collected cyanobacterial samples, 14 were grown successfully under laboratory conditions and 10 of them showed optimum growth at 45 °C. However, four strains displayed preference for lower temperature (27 °C) for optimum growth. The polyphasic characterization of 14 strains revealed that all the thermophiles belonged to the genus Mastigocladus whereas the strains Sytonema sp. TPJ-3, Calothrix sp. TPB-2, Westiellopsis sp. TPR-29 and Desikacharya sp. TPB-4 constituted the group of mesophiles. Calothrix sp. TPB-2 was identified as a novel genus (Neocalothrix thermalis) based on distinct morphology and phylogenetic position with unique ITS folding pattern. Additionally, our study disclosed the production of comparatively higher amounts of pigments and medium chain length fatty acids (C16 to C18) by the thermophilic strains, which indicated their potential to be used as feedstocks for pigments and biofuel production respectively. Although the triclosan bioremediation study reflected considerable triclosan removal efficiencies of all the strains, most impressive results were observed in case of Westiellopsis sp. TPR-29 (93.08 %) and Mastigocladus sp. TA-8 (91.92 %). Moreover, the in-silico study-based revelation of high triclosan binding ability of cyanobacterial laccase (−5.8 and − 5.4 kcal/mol) and catechol 2,3-dioxygenase (−5.9 and − 6.0 kcal/mol) suggested the probable triclosan degrading potential of Westiellopsis and Mastigocladus. Conclusively, the Tatapani hot spring represents a unique environment with the dominance of true-branched heterocytous thermophilic cyanobacteria that have enormous potential to remove triclosan and produce high amounts of pigments and medium chain length fatty acids.

Фотосинтетическая активность подроста хвойных в связи с промышленными рубками

The functioning of coniferous undergrowth of preliminary and subsequent generations after industrial felling was considered in the middle taiga subzone of the Komi Republic. Using spectrophotometric and gasometric methods we analyzed the pigment activity, photosynthetic, and respiratory abilities of the assimilation apparatus of pine (Pinus sylvestris L.) and spruce (Picea obovata Ledeb.) undergrowth at the 3- and 10-year old clearings. The pigment apparatus functional rearrangement of the preliminary generation spruce undergrowth at clearings was found. Needles adapt to environmental conditions at the pigment system level by changing the content and ratio of chlorophylls and carotenoids. Changes in plastids in the spruce undergrowth at the 3-year clearings occurred due to a decrease in chlorophyll and carotenoid concentrations, and at the 10-year clearings due to activation of pigment synthesis which affects the carbon dioxide absorption in chloroplasts. The assimilation apparatus of spruce undergrowth at clearing absorbs CO2 by 1.4 and 1.8 time more actively than that under the forest canopy. The photosynthetic and respiratory abilities of spruce needles at clearings do not differ. This indicates a stable level of important vital processes for the studied undergrowth at clearings during ten years after felling. Pine and spruce undergrowth needles are able to absorb CO2 at a fairly high rate up to 5.73 and 2.7 μmol CO2/(m2 · s) respectively. This rate contributes to the accumulation of assimilates in pine needles and their use for growth which logically increases the productivity of undergrowth at clearings. In general, the functional organization of spruce and pine undergrowth assimilating organs ensures their growth and favors the successful restoration of conifers at clearings in the middle taiga subzone of the European North-East.

Comprehensive assessment of the adaptive capability of representatives of the genus Quercus under arid climate

Woody plants that are promising for agroforestry and protective afforestation in the arid zone are increasingly exposed to the strongest abiotic factors, such as drought and high soil salinity. This influence leads to the weakening or death of woody plants, both native and introduced species. Based on a comprehensive assessment of the adaptive capacity, the pigment system of woody plants changes depending on the species specificity and the intensity of the impact of abiotic factors. Representatives of the genus Oak are widely distributed in the sparsely forested region of the dry steppes of the Volgograd region. In this regard, the aim of the work was to conduct a comprehensive assessment of the adaptive ability of representatives of the Oak genus and to identify the relationship between the integral indicators of the success of introduction and the content of photosynthetic pigments in an arid climate. For the study were selected: two forms of pedunculate oak - sprawling and pyramidal and red oak. Conducting a comprehensive assessment of the success of adaptation showed that the introduced red oak has a good adaptive ability to arid conditions, while the forms of English oak, being aborigines, showed excellent results. The study of the content of pigments of the photosynthetic system made it possible to determine that in two forms of pedunculate oak, the content of pigments is 2-4 times higher than in the introduced red oak (p<0.05). It can be concluded that abiotic factors affect the content of pigments and, in general, the adaptive capacity of woody plants in arid climates. The study made it possible to reveal the existence of a relationship between the adaptive capacity and the content of pigments of the photosynthetic system in representatives of the Oak genus, which are promising introducers of arid territories for solving the problems of agroforestry and protective afforestation.

The influence of agrochemicals of regulatory action on tea plants’ pigment System

The influence of agrochemicals of regulatory action on tea plants’ pigment System

The content of photosynthetic pigments in thallomas of Parmelia sulcata Taylor in recreational areas of the city of Tver and the Spirovsky district of the Tver region

To date, the assessment of the qualitative and quantitative content of assimilating pigments in lichen thallomas is one of the most common indicators for identifying the degree of damage to these organisms in conditions of environmental pollution. The aim of the work is to assess the content of photosynthetic pigments (chlorophyll a and b) in the thallus of Parmelia sulcata Taylor lichen in the ecosystems of Tver and the Spirovsky district of the Tver region with varying degrees of anthropogenic transformation. The study of the pigment content in the samples of lichen P. sulcata collected in the recreational areas of the city of Tver and the village of Spirovo with different levels of anthropogenic transformation and pollution. Significant differences in the content of chlorophylls a and b were found, which indicates a high plasticity of the photosynthetic system. The level of Cl a content in recreational areas is higher than in background conditions. The high variability of the values of the concentrations of Cl b indicates the priority value of the pigment system during adaptation.

Investigating the Interplay between Tomato Leaf Curl New Delhi Virus Infection, Starch Metabolism and Antioxidant Defence System in Potato (Solanum tuberosum L.).

The potato apical leaf curl disease is caused by tomato leaf curl New Delhi virus-potato (ToLCNDV-potato), which severely alters a plant's starch metabolism, starch hydrolysing enzymes, and antioxidant mechanism. In this study, the result suggested that ToLCNDV-potato significantly (p < 0.01) affected the morphological parameters and photosynthetic pigment system in both the cultivars of potato, viz., Kufri Pukhraj (susceptible) and Kufri Bahar (tolerant). However, the impact of ToLCNDV-potato was lower in Kufri Bahar. Moreover, the viral infection in potato showed significant (p < 0.01) enhancement in the leakage of plant oxidative metabolites such as proline and malondialdehyde (MDA) which was further confirmed with higher electrolyte leakage. The viral infection imbalance of starch metabolism in the leaves ultimately affects the carbohydrate profile. ToLCNDV-potato significantly lowered starch synthesis, enhanced the accumulation of sucrose, glucose, fructose and-which was further validated by enzymatic estimation of β-amylase-α-amylase and phosphorylase activity in the leaves of both cultivars. The antioxidant enzymes, viz., catalase, ascorbate peroxidase, and superoxide dismutase, were reported to be enhanced in both the cultivars due to ToLCNDV-potato infection. The higher enhancement of antioxidant enzyme activity was observed in Kufri Bahar, which signifies its resistant attributes. These findings in the potato plant broaden our understanding of the regulatory mechanisms of starch metabolism and antioxidant activity and provide proof of concept for breeding potato for ToLCNDV-potato tolerance.

Plant growth promoting potential of urea doped calcium phosphate nanoparticles in finger millet (Eleusine coracana (L.) Gaertn.) under drought stress.

Drought is a leading threat that impinges on plant growth and productivity. Nanotechnology is considered an adequate tool for resolving various environmental issues by offering avant-garde and pragmatic solutions. Using nutrients in the nano-scale including CaP-U NPs is a novel fertilization strategy for crops. The present study was conducted to develop and utilize environment-friendly urea nanoparticles (NPs) based nano-fertilizers as a crop nutrient. The high solubility of urea molecules was controlled by integrating them with a matrix of calcium phosphate nanoparticles (CaP NPs). CaP NPs contain high phosphorous and outstanding biocompatibility. Scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD) were used to characterize the fabricated NPs. FE-SEM determined no areas of phase separation in urea and calcium phosphate, indicating the successful formation of an encapsulated nanocomposite between the two nano matrices. TEM examination confirmed a fiber-like structure of CaP-U NPs with 15 to 50 nm diameter and 100 to 200 nm length. The synthesized CaP-U NPs and bulk urea (0.0, 0.1% and 0.5%) were applied by foliar sprays at an interval of 15 days on pre-sowed VL-379 variety of finger millet (Eleusine coracana (L.) Gaertn.), under irrigated and drought conditions. The application of the CaP-U NPs significantly enhanced different plant growth attributes such as shoot length (29.4 & 41%), root length (46.4 & 51%), shoot fresh (33.6 & 55.8%) and dry weight (63 & 59.1%), and root fresh (57 & 61%) and dry weight (78 & 80.7%), improved pigment system (chlorophyll) and activated plant defense enzymes such as proline (35.4%), superoxide dismutase (47.7%), guaiacol peroxidase (30.2%), ascorbate peroxidase (70%) under both irrigated and drought conditions. Superimposition of five treatment combinations on drought suggested that CaP-U NPs at 0.5 followed by 0.1% provided the highest growth indices and defense-related enzymes, which were significantly different. Overall, our findings suggested that synthesized CaP-U NPs treatment of finger millet seeds improved plant growth and enzymatic regulation, particularly more in drought conditions providing insight into the strategy for not only finger millet but probably for other commercial cereals crops which suffer from fluctuating environmental conditions.

A study of auditory brainstem response in vitiligo patients

Introduction and Aim: Vitiligo is a hypomelanotic, idiopathic disease influencing entire pigmentary system which includes stria vascularis of internal ear described by depigmented patches in the skin because of absence of melanin and functioning melanocytes in the epidermis. The aim of this study was to assess the audiological irregularities by assessing the brain stem auditory evoked potential in vitiligo patients and comparing with the healthy controls. Materials and Methods: Forty clinically confirmed vitiligo patients of 20 to 40 years of both genders, with or without therapy were enlisted from the Dermatology and cosmetology outpatient clinics, Government Stanley Hospital. Forty controls with similar ages and genders were chosen. The Neuro perfect Medicaid polyrite instrument was used in recording Brainstem Evoked Reaction Audiometry (BERA) in both vitiligo individuals and controls. Inter-Peak Latencies (IPL) and Absolute Wave Latencies (AWL)were measured and analysed by using SPSS version 17. Student's independent 't' test was done for comparing the groups. Results: AWL and IPL of the two ears were measured and both were compared in the study and control groups. In the left ear, AWL III of study subjects had a significant increase 3.34+0.16 than that of controls 3.27+0.19; IPL I-III also significantly increased in the study subjects 1.91+0.16 than the controls 1.77+0.17. In the right ear, AWL III of study subjects had a significant increase 3.18+0.17 than the controls 3.06+0.15; IPL I-III also significantly increased in the study subjects 1.79+0.17 than the controls 1.64+0.16. Conclusion: BERA findings were abnormal in clinically asymptomatic research subjects, suggesting that this test should be included in the routine follow-up of vitiligo patients to detect audiological subclinical involvement.

Photoinduced Dynamics of 13,13'-Diphenylpropyl-β-carotene.

Carotenoids are ubiquitous pigment systems in nature which are relevant to a range of processes, such as photosynthesis, but the detailed influence of substitutions at the polyene backbone on their photophysics is still underexplored. Here, we present a detailed experimental and theoretical investigation of the carotenoid 13,13'-diphenylpropyl-β-carotene using ultrafast transient absorption spectroscopy and steady-state absorption experiments in n-hexane and n-hexadecane, complemented by DFT/TDDFT calculations. In spite of their bulkiness and their potential capability to "fold back" onto the polyene system, which could result in π-stacking effects, the phenylpropyl residues have only a minor impact on the photophysical properties compared with the parent compound β-carotene. Ultrafast spectroscopy finds lifetimes of 200-300 fs for the S2 state and 8.3-9.5 ps for the S1 state. Intramolecular vibrational redistribution with time constants in the range 0.6-1.4 ps is observed in terms of a spectral narrowing of the S1 spectrum over time. We also find clear indications of the presence of vibrationally hot molecules in the ground electronic state (S0*). The DFT/TDDFT calculations confirm that the propyl spacer electronically decouples the phenyl and polyene π-systems and that the substituents in the 13 and 13' positions point away from the polyene system.

The story of melanocyte: a long way from bench to bedside.

Skin is composed of major layers, namely a superficial epidermis and a deeper dermis. The color of skin is influenced by a number of pigments, including melanin, which is produced by cells called melanocytes. Most skin disorders are relatively benign, but a few, including melanomas, can be fatal. A number of more noticeable disorders, namely albinism and vitiligo, affect the appearance of the skin and its accessory organs. Vitiligo is associated with significant psycho-social morbidity and a major effect on quality of life. Topical steroids, calcineurin inhibitors, phototherapy and surgery are the most common treatments for melanoma. However, there are many patients who do not respond to any of these modalities. The transplantation of cultured or non-cultured melanocyte is the most important treatment for hypopigmentory disorders. This study aims at reviewing the history of melanocyte cultivation, and evaluating the effectiveness of transplantation of cultured cells. For this purpose, the authors examined the initial process of isolation, characterization, and transplantation of epidermal cells. This review, thus, summarizes the current understanding of the cutaneous pigmentary system from the start of synthesis in the pigment cells, along with the response of repigmentation. During the production of melanin, melanosomes are transferred to neighboring keratinocyte in order to form perinuclear melanin caps. The objective of this review is to analyze the melanocytes transplantation in the last century to date, and explore the methods epidermal cells can increase pigmentation in hypo-pigmented areas in skin disorders. Moreover, the focus is on the story of the melanocyte back to 1950s. In addition, prior systemic therapy was associated with a significant increase, based on combined additional therapy, achieving desired results and improved outcomes. Despite the short study of a long way of melanocyte assessment and following up patient treatment, results of the all reports confirmed the efficacy of the method used in the treatment of stable vitiligo patients, who did not respond to the common algorithms of non-invasive treatments.

Pigment cell progenitor heterogeneity and reiteration of developmental signaling underlie melanocyte regeneration in zebrafish.

Tissue-resident stem and progenitor cells are present in many adult organs, where they are important for organ homeostasis and repair in response to injury. However, the signals that activate these cells and the mechanisms governing how these cells renew or differentiate are highly context-dependent and incompletely understood, particularly in non-hematopoietic tissues. In the skin, melanocyte stem and progenitor cells are responsible for replenishing mature pigmented melanocytes. In mammals, these cells reside in the hair follicle bulge and bulb niches where they are activated during homeostatic hair follicle turnover and following melanocyte destruction, as occurs in vitiligo and other skin hypopigmentation disorders. Recently, we identified melanocyte progenitors in adult zebrafish skin. To elucidate mechanisms governing melanocyte progenitor renewal and differentiation we analyzed individual transcriptomes from thousands of melanocyte lineage cells during the regeneration process. We identified transcriptional signatures for progenitors, deciphered transcriptional changes and intermediate cell states during regeneration, and analyzed cell-cell signaling changes to discover mechanisms governing melanocyte regeneration. We identified KIT signaling via the RAS/MAPK pathway as a regulator of melanocyte progenitor direct differentiation and asymmetric division. Our findings show how activation of different subpopulations of mitfa-positive cells underlies cellular transitions required to properly reconstitute the melanocyte pigmentary system following injury.

Short-term effects of α-melanocyte-stimulating hormone in three distinct melanin-pigmented cell types of Anura.

Ectothermic animals present melanin-containing cells in their integument and viscera. Besides cutaneous melanophores, amphibians have melanomacrophages in the hepatic parenchyma and melanocytes in the viscera, which are also present in their testicular stroma. The native melanocyte stimulating hormone (α-MSH) is the main hormone that modulates the color change in melanophores. However, we still know too little about how the α-MSH acts in vivo on visceral melanin-containing cells. In this study, we collected 30 adult males of Physalaemus nattereri (Anura, Leptodactylidae) to evaluate the short-term effects of α-MSH on melanophores, melanocytes and melanomacrophages under light microscopy. For this, we injected 0.05 ml of a single intraperitoneal dose containing 2.5x10-7 mmol/10g of α-MSH, diluted in ringer solution, in five experimental groups with five individuals each one. The different groups were analyzed after 1, 3, 6, 12 and 24h. The control group with five other individuals received only 0.05 ml of ringer solution. The skin pigmentation increased quickly after animals received the hormone α-MSH with the consequent darkening of the body (body darkness). Melanophores, melanocytes and melanomacrophages responded similarly to the test, with an increase in the area containing melanin. However, melanophores and melanomacrophages reached their darkest pigmentation in a shorter period of time in comparison to the testicular melanocytes, probably due to specific metabolic characteristics of each organ. Thus, we verified that the three types of cells, although present in different organs, are responsive to the native hormone α-MSH, which enables us to treat them as a pigmentary system.

Особливості функціонування пігментного комплексу та урожайність агрусу (Ribes uva-crispa L.) вітчизняної селекції у Західному Лісостепу України

We diagnosed the functional state and potential productivity of the pigment complex of the gooseberry of domestic selection in the conditions of the Western Lisosteppe of Ukraine. We established relationships between functional stability, efficiency of the photosynthetic apparatus and economic productivity of valuable forms of this culture. In comparison with the control variant of gooseberry variety Nesluhivskyi, the hybrid forms of selection of IH NAAS Lasunok, Medovyi, as well as varieties Petrivka, Kholodnyi Yar surpassed the control in terms of individual indicators of potential productivity and functional state of the photosynthetic apparatus. Our study of the relationship between the actual productivity of gooseberry and the features of the functioning of the pigment complex showed that the economic productivity was ensured to a greater extent by the productivity potential of the pigment complex in terms of maximum fluorescence and the rate of energy transfer to the synthesis of organic matter. This is confirmed by the inversely proportional correlation between the actual productivity of experimental gooseberry plants and their productivity potential according to the first wave of fluorescence (r = -0.60). This wave (Fmax1) characterizes the potential of the pigment system regarding the transformation of accumulated energy into compounds of organic synthesis. A medium-level negative correlation (r = -0.58) was also established between productivity and Ki1. The last coefficient reveals the efficiency of light transmission near the reaction centers of photosystem II. At the same time, he takes into account the influence of stress factors that prevent the normal operation of the photosynthetic system in the light phase. The functional state of all experimental plants was high. Accordingly, the level of correlation between yield and functional state (as a factor at the maximum) of plants in the studies was low (less than ± 0.2). According to the set of fluorescent indicators considered in the article, the varieties and hybrid forms of gooseberry were characterized by sufficient stability of functioning and productivity of the pigment complex of leaves to ensure economic productivity in the conditions of the Western Lisosteppe of Ukraine. In terms of productivity potential, the investigated variants were superior to Nesluhivskyi (control), one of the best varieties of domestic selection. The promising hybrid form of gooseberry Medovyi, and varieties Petrivka, Kholodnyi Yar were noted for intensive accumulation of organic compounds. These three options were marked by the highest actual productivity (on average over the years of research, 15.7-17.0 t/ha). According to the results of the initial varietal study, gooseberries Kholodnyi Yar, Petrivka were submitted to the state register of Ukraine. Promising hybrid forms Lasunok, Medovyi are undergoing the final stages of initial varietal study. Key words: gooseberry, variety, hybrid forms, chlorophyll fluorescence, photosynthesis, leaf apparatus, potential productivity, productivity.

Peculiarities of the Influence of Oil Products on the Content and Ratio of Photosynthetic Pigments of Ceratophyllum demersum L.

As a result of the performed investigations, it has been found that at the concentration of oil products, including petrol and diesel fuel, of 5.0 and 10.0 mg/L the content of photosynthetic pigments (chlorophylls &lt;i&gt;a&lt;/i&gt; and &lt;i&gt;b&lt;/i&gt; and carotenoids), and also (chlorophyll &lt;i&gt;a&lt;/i&gt;/chlorophyll &lt;i&gt;b&lt;/i&gt;) and (chlorophyll &lt;i&gt;a&lt;/i&gt; &amp;#43; chlorophyll &lt;i&gt;b&lt;/i&gt;)/carotenoids ratios significantly decreased, which is indicative of inhibiting the vital activity of macrophytes. It has been shown that the pigment system of &lt;i&gt;C. demersum &lt;/i&gt;proved to be rather resistant to the influence of the concentrations of petrol and diesel fuel of 0.5 and 1.0 mg/L. This fact suggests that this species of higher aquatic plants can be used for phytoremediation of the aquatic environment moderately contaminated by oil products.

Полиморфизм локуса rs4264393 гена PRDM7 в популяциях коренного населения Сибири: возможная связь с особенностями пигментации кожи в условиях Крайнего Севера

The rs4264393-G allele of the PRDM7 gene belongs to the polymorphic variants very frequent only in indigenous populations of northeastern Siberia: in Eskimos, Chukchi, and Koryaks, its frequency is 64 %. The results of the paleogenomic data analysis suggest that the rs4264393-G variant was present in the north of modern Yakutia (Duvannyi Yar site) about 10 thousand years ago and probably appeared in Northeast Asia even earlier, during the presumed migrations of East Asian populations (20-18 thousand years ago), which mixed with the Upper Paleolithic groups of North Siberia and gave rise to the ancestors of Paleosiberian populations and Amerindians. The PRDM7 gene encodes for a methyltransferase, involved in histone modification, and appears to be an active regulator of gene activity in melanocytes. The findings are discussed in connection with the peculiarities of Eskimo and Paleo-Asiatic skin pigmentation and the possibility that the rs4264393-G variant of the PRDM7 gene may be involved in the evolution of the Arctic peoples pigmentation system.

NRF2 in the Epidermal Pigmentary System.

Melanogenesis is a major part of the environmental responses and tissue development of the integumentary system. The balance between reduction and oxidation (redox) governs pigmentary responses, for which coordination among epidermal resident cells is indispensable. Here, we review the current understanding of melanocyte biology with a particular focus on the "master regulator" of oxidative stress responses (i.e., the Kelch-like erythroid cell-derived protein with cap'n'collar homology-associated protein 1-nuclear factor erythroid-2-related factor 2 system) and the autoimmune pigment disorder vitiligo. Our investigation revealed that the former is essential in pigmentogenesis, whereas the latter results from unbalanced redox homeostasis and/or defective intercellular communication in the interfollicular epidermis (IFE). Finally, we propose a model in which keratinocytes provide a "niche" for differentiated melanocytes and may "imprint" IFE pigmentation.

Функциональная характеристика хвои подроста ели сибирской под пологом и на вырубке ельника черничного в подзоне средней тайги

Currently, the coniferous undergrowth preservation in the cuttings of the boreal zone is of great importance for the accelerated restoration of coniferous forests. When assessing the natural regeneration of forests in clear cuttings of the North, it is important to know the basic life activity processes of the undergrowth that survived after logging. An attempt to consider these issues from a physiological point of view has been made. The pigment activity and carbon dioxide gas exchange of spruce undergrowth needles caused by industrial logging in the middle taiga subzone of the Komi Republic was studied. This article provides a comparative analysis of the photosynthetic apparatus physiological parameters of the 20-year-old spruce undergrowth under the canopy of the bilberry spruce forest and in the 8-10-year-old clear cutting. Changes in the undergrowth pigment pool due to spruce forest felling were revealed. In a damp spruce bilberry forest, the spruce undergrowth needles accumulate chlorophylls and carotenoids; 1.08–1.63 and 0.26–0.37 mg/g of dry weight, respectively. The concentration of green and yellow pigments in the spruce undergrowth needles is 18–25 and 18–35 % higher in the clear cutting than under the canopy. The undergrowth photosynthetic apparatus in the clear cutting adapts to environmental conditions at the pigment system level by activating the synthesis of chlorophylls and carotenoids. The seasonal rhythm of pigment content was the same in the spruce undergrowth in the clear cuttings and under the canopy of the bilberry spruce forest. The greatest amount of pigments was observed in autumn, which is an adaptive trait that ensures the resistance of the assimilation apparatus to the Northern conditions along with other mechanisms. We have found that the photosynthetic capacity (2.69 μmol CO2/(m2 ∙ s)) of the spruce undergrowth needles in the cutting is 1.5 times higher than in the bilberry spruce forest, which contributes to the assimilates accumulation and their use in growth processes. The spruce undergrowth needles in the cutting have a low respiratory capacity (0.20 μmol CO2/(m2 ∙ s)), which leads to an improved carbon balance. The obtained data provide the basis for modeling the behavior of natural regeneration of forests and can be used to address issues of improving the functioning of spruce forests during their intensive operation in the Komi Republic. Acknowledgements: The research was carried out within the framework of the state assignment of the Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences (state registration No. 1021051101417-8-1.6.19). For citation: Tuzhilkina V.V. Functional Characteristics of Siberian Spruce Undergrowth Needles under the Canopy and in the Cutting of Bilberry Spruce Forest in the Middle Taiga Subzone. Lesnoy Zhurnal = Russian Forestry Journal, 2022, no. 6, pp. 107–116. (In Russ.). https://doi.org/10.37482/0536-1036-2022-6-107-116

Стрес-індуковані реакції мохів на періодичне короткочасне і тривале висушування залежно від водного режиму їхніх місцевиростань

Bryophytes are poikilohydric higher plants and their water content as well as metabolic activity depend on the water regime of the environment. The aim of the study was to establish the features of stress-induced reactions of mosses under controlled conditions of short-term and long-term drying depending on the water regime of their habitats. A culture of shoots of the same age from agar mediums the same level of relative humidity was used to study the effect of periodic drying. Dehydration was carried out within 24 hours, removing the polyethylene cover from the pots with moss culture. Plant watering was carried out twice a week in the variant of the experiment with short-term drying: immediately after dehydration and on the third day after drying. In the variant with long-term drying plants were watered once a week – on the third day after 24-hour dehydration. Control plants were sprayed twice a week. A significant decrease in the size of shoots, leaves and an increase in the density of moss turf under the influence of short-term and long-term drying have been established, based on the analysis of morphometric parameters of Barbula unguiculata Hedw. and Physcomitrella patens (Hedw.) Bruch &amp; Schimp. In the moss Weissia longifolia Mitt. long-term drying caused a slight increase in leaf size and elongation of shoots, comparing with control and short-term drying, and at the same time activated the formation of chloronеmal dendroids, which proved its greatest adaptability and ability to adapt to perio­dic changes in humidity. A higher sensitivity of the pigment system of B. unguiculata and P. patens to drying compared to W. longifolia was established. It was found that in the pigment system of the hygromesophytic moss P. patens the significant role belongs to chlorophyll b and pheophytin b, functioning of the assimilation complex of the xeromesophytic moss Barbula unguiculata depends on chlorophyll a and pheophytin a, in xerophytic moss W. longifolia – due to the stability of chlorophyll a and the strength of the bound of carotenoids with protein complexes of the pigment system. The dependence of the component composition of the pigment apparatus, the strength of the bond of pigment-protein complexes (PPC), the activity of chlorophyllase, and the total carbohydrate content of the studied mosses on the duration of drying and their species characteristics was determined.