Symbiotic Forms Research Articles

Dynamics of Hydrogen Peroxide Accumulation During Tip Growth of Infection Thread in Nodules and Cell Differentiation in Pea (Pisum sativum L.) Symbiotic Nodules.

Hydrogen peroxide (H2O2) in plants is produced in relatively large amounts and plays a universal role in plant defense and physiological responses, including the regulation of growth and development. In the Rhizobium-legume symbiosis, hydrogen peroxide plays an important signaling role throughout the development of this interaction. In the functioning nodule, H2O2 has been shown to be involved in bacterial differentiation into the symbiotic form and in nodule senescence. In this study, the pattern of H2O2 accumulation in pea (Pisum sativum L.) wild-type and mutant nodules blocked at different stages of the infection process was analyzed using a cytochemical reaction with cerium chloride. The observed dynamics of H2O2 deposition in the infection thread walls indicated that the distribution of H2O2 was apparently related to the stiffness of the infection thread wall. The dynamics of H2O2 accumulation was traced, and its patterns in different nodule zones were determined in order to investigate the relationship of H2O2 localization and distribution with the stages of symbiotic nodule development in P. sativum. The patterns of H2O2 localization in different zones of the indeterminate nodule have been partially confirmed by comparative analysis on mutant genotypes.

Two members of a Nodule-specific Cysteine-Rich (NCR) peptide gene cluster are required for differentiation of rhizobia in Medicago truncatula nodules.

Legumes have evolved a nitrogen-fixing symbiotic interaction with rhizobia, and this association helps them to cope with the limited nitrogen conditions in soil. The compatible interaction between the host plant and rhizobia leads to the formation of root nodules, wherein internalization and transition of rhizobia into their symbiotic form, termed bacteroids, occur. Rhizobia in the nodules of the Inverted Repeat-Lacking Clade legumes, including Medicago truncatula, undergo terminal differentiation, resulting in elongated and endoreduplicated bacteroids. This transition of endocytosed rhizobia is mediated by a large gene family of host-produced nodule-specific cysteine-rich (NCR) peptides in M. truncatula. Few NCRs have been recently found to be essential for complete differentiation and persistence of bacteroids. Here, we show that a M. truncatula symbiotic mutant FN9285, defective in the complete transition of rhizobia, is deficient in a cluster of NCR genes. More specifically, we show that the loss of the duplicated genes NCR086 and NCR314 in the A17 genotype, found in a single copy in Medicago littoralis R108, is responsible for the ineffective symbiotic phenotype of FN9285. The NCR086 and NCR314 gene pair encodes the same mature peptide but their transcriptional activity varies considerably. Nevertheless, both genes can restore the effective symbiosis in FN9285 indicating that their complementation ability does not depend on the strength of their expression activity. The identification of the NCR086/NCR314 peptide, essential for complete bacteroid differentiation, has extended the list of peptides, from a gene family of several hundred members, that are essential for effective nitrogen-fixing symbiosis in M. truncatula.

Molecular Mimicry of NodA Genes by an N-acetylmuramoyl-L-alanine Amidases Gene in a Nodule Forming Staphylococcus cohnii [RESEARCH NOTE

A rare, nodule-forming, Gram-positive bacterium (Sub4) was isolated from the forage and cover crop Pueraria phaseoloides, which aligned at 99.26% sequence identity to a partial 16S rDNA sequence of Staphylococcus cohnii sp. This was the first record of a strain/species of Staphylococcus capable of independent, unassisted nodule formation in a legume host. When a nodA gene was sought by PCR using a pair of gene-specific primers synthesized using a related (Firmicutes) Paenibacillus sp. nodA gene, the reaction yielded a PCR product of similar size but a distinct identity. The resulting ~400bp PCR product coded for a likely N-acetylmuramoyl-L-alanine amidase and not an acyltransferase. It may be inferred that the N-acetylmuramoyl-L-alanine amidase gene was amplified due to sequence similarities/mimicry between 2 cosmetically unrelated loci. There was also an analogy in protein backbones between homology models of the Sub4 N-acetylmuramoyl-L-alanine amidase and a Paenibacillus nodA gene product, which also suggests that the 2 protein families may have an evolutionary relationship. When the phylogeny of the sequenced locus was inferred, a unique clade with high bootstrap support was formed by the sequence under study with an Azorhizobium nodA gene. Azorhizobia were distinct in relation to their nodule formation on stems and their ability to fix nitrogen in the free-living and the symbiotic forms. N-acetylmuramoyl-L-alanine amidases may have roles to play in remodeling peptidoglycan for LysM receptor interactions, likely without nod factors.

Forests as Markets

This essay argues for the deep affinities between neoliberalism and environmental thought that embraces such figures as fungi, swarms, and especially trees. While critics like Rob Nixon turn to trees to promote modes of cooperative biology and plant communication as blueprints for more symbiotic forms of sociality that offer alternatives to “hyperindividualism and hyperconsumption,” they share with neoliberalism a more fundamental ontology of what Friedrich Hayek (after Michael Polanyi) calls “spontaneous order.” Drawing on recent revisionary scholarship on neoliberalism, the first half of the essay argues that neoliberalism is less usefully thought of as an individualist anthropology than as a worldview that subordinates individuals to a nontransparent and distributed higher intelligence—that of the market. The second half of the essay illustrates the uncomfortable overlap between neoliberal and environmental imaginaries through a discussion of Richard Powers’s celebrated novel The Overstory. The overwhelmingly positive reception of the novel has praised its power to embody the arboreal life cycle it represents, but it has remained curiously blind to the way the novel’s formal choices ask its characters to submit to the powers of a superior computerized intelligence—a gesture that is conspicuously close to the way neoliberalism compels individuals’ submission to nontransparent market forces. The novel and its critical reception, like particular strands in the environmental humanities more generally, show that the opposition between the environmental imagination and neoliberalism is neutralized by a shared commitment to fictions of spontaneous order.

Ecolichenology of Eastern Ghats diversity against climatic fluctuations in Kolli Hills, India

Abstract. Subbaiyan R, Ganesan A, Dhanuskodi S. 2023. Ecolichenology of Eastern Ghats diversity against climatic fluctuations in Kolli Hills, India. Biodiversitas 24: 625-635. Lichens are major components of earthbound and marine environments. A lichen is a symbiotic form of algae and fungi adapted to survive in different altitudes and environmental conditions. The lichen morphology is divided into three, based on their habitat: crustose, foliose, and fruticose lichens. Eastern Ghats (EG) contribute significantly to both the endemicity and species richness of the Indian region. However, EG forests are relatively unexplored and have received less conservation consideration than the Western Ghats. Unexplored Eastern Ghats were studied to analyze the ecolichenology against climatic fluctuations. The objective of this paper is to build a stock of epiphytic lichens within the Kolli slopes. Kolli Hills are one of the ancient richest floral and faunal biodiversity hotspots of Eastern Ghats. It is assessed from the year 2018 to that 2021 with different climatic seasonal variations. The least diversity was found with the Arthonioid > Usneoid > Scaly > Ramalinoid types. Highly denser than the Parmelioid foliose and Usneoid, the Ramlinoid species was rich in numbers with healthy thallus. The population was stopped, or the least amount of thallus growth was noticed from the high rainfall season and gradual reduction in the summer. The Ramalinoid and Parmelioid lichens were found to be easy identifiers. The richness was reduced dependently and independently with nature. The health of lichens was encountered with only morphological appurtenance. Based on the lichen group, the maximum distribution was observed in Usneoid and Ramalinoid categories. The last distribution was found with Leprose and Scaly lichens. The forest wealth was described with the denser lichen patches and the shrinkages of Parmelioid lichens, especially the Dirinaria and Parmoterma, acting as a wealth analysis tool of the forest ecosystems.

Imaginaries on ice: Sociotechnical futures of data centre development in Norway and Iceland

In 2018, Norway promoted itself as a ‘Datacentre Nation’. In terms of low cost, renewably generated sources of electricity and low ambient temperatures, Nordic countries and the data centre sector are potentially mutual beneficiaries – yet, there are also negative impacts associated with the necessary electric power production. With this as a starting point, for Norway and Iceland, we explore how data centre proponents promulgate similar techno-environmental imaginaries, but achieve differing degrees of stabilisation. To this end, we use three sources of imaginaries relating to data centre development in Iceland and Norway: those implicit in promotional imagery originating within the countries concerned; those implicit in international newspapers, as indicative of external perceptions; and those implicit in focus groups with the Norwegian and Icelandic public. We show how data centre advocates deploy visual imagery to create a promotional techno-environmental imaginary that marries nature with the digital in a symbiotic form, and we observe that this is largely consistent with the more mundane international imaginary of Norwegian data centres. For Iceland, however, the external imaginary is dominated by associations of excess energy consumption by bitcoin mining. For the publics questioned, there are multiple imaginaries of data centres, with significant notes of moral and other forms of scepticism. Looking ahead, we suggest that for long-term stabilisation of positive data centre imaginaries, conducive to investment, the capacity of Iceland and Norway to equitably supply sufficient renewable power will need to be addressed as a matter of urgency.

A variable gene family encoding nodule-specific cysteine-rich peptides in pea (Pisum sativum L.)

Various legume plants form root nodules in which symbiotic bacteria (rhizobia) fix atmospheric nitrogen after differentiation into a symbiotic form named bacteroids. In some legume species, bacteroid differentiation is promoted by defensin-like nodule-specific cysteine-rich (NCR) peptides. NCR peptides have best been studied in the model legume Medicago truncatula Gaertn., while in many other legumes relevant information is still fragmentary. Here, we characterize the NCR gene family in pea (Pisum sativum L.) using genomic and transcriptomic data. We found 360 genes encoding NCR peptides that are expressed in nodules. The sequences of pea NCR genes and putative peptides are highly variable and differ significantly from NCR sequences of M. truncatula. Indeed, only one pair of orthologs (PsNCR47–MtNCR312) has been identified. The NCR genes in the pea genome are located in clusters, and the expression patterns of NCR genes from one cluster tend to be similar. These data support the idea of independent evolution of NCR genes by duplication and diversification in related legume species. We also described spatiotemporal expression profiles of NCRs and identified specific transcription factor (TF) binding sites in promoters of “early” and “late” NCR genes. Further, we studied the expression of NCR genes in nodules of Fix– mutants and predicted potential regulators of NCR gene expression, one among them being the TF ERN1 involved in the early steps of nodule organogenesis. In general, this study contributes to understanding the functions of NCRs in legume nodules and contributes to understanding the diversity and potential antibiotic properties of pea nodule-specific antimicrobial molecules.

DNA Methylation Patterns Differ between Free-Living Rhizobium leguminosarum RCAM1026 and Bacteroids Formed in Symbiosis with Pea (Pisum sativum L.).

Rhizobium leguminosarum (Rl) is a common name for several genospecies of rhizobia able to form nitrogen-fixing nodules on the roots of pea (Pisum sativum L.) while undergoing terminal differentiation into a symbiotic form called bacteroids. In this work, we used Oxford Nanopore sequencing to analyze the genome methylation states of the free-living and differentiated forms of the Rl strain RCAM1026. The complete genome was assembled; no significant genome rearrangements between the cell forms were observed, but the relative abundances of replicons were different. GANTC, GGCGCC, and GATC methylated motifs were found in the genome, along with genes encoding methyltransferases with matching predicted target motifs. The GGCGCC motif was completely methylated in both states, with two restriction–modification clusters on different replicons enforcing this specific pattern of methylation. Methylation patterns for the GANTC and GATC motifs differed significantly depending on the cell state, which indicates their possible connection to the regulation of symbiotic differentiation. Further investigation into the differences of methylation patterns in the bacterial genomes coupled with gene expression analysis is needed to elucidate the function of bacterial epigenetic regulation in nitrogen-fixing symbiosis.

Research on the Symbiosis of Public Art and Urban Art

Public art and urban art are two independent and interdependent concepts. Public art is characterized by publicity, which refers to the unique artistic features displayed in the urban public domain. Urban art is relatively restrained and implicit, which refers to the historical culture accumulated in the historical development of the city. However, there is a certain commonality between them, which can influence each other, promote each other and develop each other, and have an important impact on contemporary urban development and urban construction. This paper mainly explores the symbiosis between public art and urban art, and further analyzes and explains the symbiotic forms between public art and urban art.

ARTIFICIAL INTELLIGENCE AS A TOOL FOR CREATING AND ANALYSING WORKS OF ART

The purpose of the article is to reveal the specifics of creating new works of art using artificial intelligence technologies. The research methodology is based on the application of the dialectical method with its principles of consistency, development and unity of polarities since artificial intelligence as a complex sociocultural phenomenon provides unambiguous definitions and at the same time forces to interpret its essence and relations dialectically to its application field. The scientific novelty of the obtained results lies in the fact that artificial intelligence is considered a component of artistic creativity, one of which is to introduce technical innovations in human culture. Conclusions. The article focuses on the fact that the artificial intelligence issue is beyond the cultural discourse, and separating the artificial intelligence issue from culture inevitably leads to a simplified understanding. It is noted that the relevance of cultural research of artificial intelligence (AI) is determined by the spread of symbiotic forms of interaction between the user and global software, which requires not so much evaluating and correcting the negative consequences of the spread of technology but rather the development of meta technology to prevent them. For its part, the reflection of culture, when the latter rejects the ideas of the techno apocalypse and the rise of machines, can give an impetus to the emergence of new meanings and perspectives for man and culture. Finally, the article provides examples of the AI technologies use (in particular, Gan and CAN) in contemporary art. However, the more AI technologies are used in creating works of art, the more valuable an idea or a concept becomes. Today, when the performance and physical implementation of a project can be “shifted” to AI, new ideas become the main driving force in the development of art. The ideas generation may become the primary option not of a person but of a “machine”, which, once again, proves the correctness of the assumption that every year such human abilities as creativity, generation of new extraordinary ideas and solutions will become more valuable. And the routine performance, the analysis of big data, etc., are the tasks for machines, and they perform this work better than a human.

Better off alone? New insights in the symbiotic relationship between the flatworm Symsagittifera roscoffensis and the microalgae Tetraselmis convolutae

The acoel flatworm Symsagittifera roscoffensis lives in obligatory symbiosis with the microalgal chlorophyte Tetraselmis convolutae. Although this interaction has been studied for more than a century, little is known on the potential reciprocal benefits of both partners, a subject that is still controversial. In order to provide new insights into this question, we have compared the photophysiology of the free-living microalgae to the symbiotic form in the flatworm, both acclimated at different light irradiances. Photosynthesis – Irradiance curves showed that the free-living T. convolutae had greater photosynthetic performance (i.e., oxygen production rates, ability to harvest light) than their symbiotic form, regardless of the light acclimation. However, they were affected by photoinhibition under high irradiances, which did not happen for the symbiotic form. The resistance of symbiotic microalgae to photoinhibition were corroborated by pigment analyses, which evidenced the induction of photoprotective mechanisms such as xanthophyll cycle as well as lutein and β-carotene accumulation. These processes were induced even under low light acclimation and exacerbated upon high light acclimation, suggesting a global stress situation for the symbiotic microalgae. We hypothesize that the internal conditions in the sub-epidermal zone of the flatworm (e.g., osmotic and pH), as well as the phototaxis toward high light imposed by the worm in its environment, would be major reasons for this chronic stress situation. Overall, our study suggests that the relationship between S. roscoffensis and T. convolutae may be a farming strategy in favor of the flatworm rather than a symbiosis with mutual benefits.

Metabolic Analyses of Nitrogen Fixation in the Soybean Microsymbiont Sinorhizobium fredii Using Constraint-Based Modeling.

Rhizobia are soil bacteria able to establish symbiosis with diverse host plants. Specifically, Sinorhizobium fredii is a soil bacterium that forms nitrogen-fixing root nodules in diverse legumes, including soybean. The strain S. fredii CCBAU45436 is a dominant sublineage of S. fredii that nodulates soybeans in alkaline-saline soils in the Huang-Huai-Hai Plain region of China. Here, we present a manually curated metabolic model of the symbiotic form of Sinorhizobium fredii CCBAU45436. A symbiosis reaction was defined to describe the specific soybean-microsymbiont association. The performance and quality of the reconstruction had a 70% score when assessed using a standardized genome-scale metabolic model test suite. The model was used to evaluate in silico single-gene knockouts to determine the genes controlling the nitrogen fixation process. One hundred forty-one of 541 genes (26%) were found to influence the symbiotic process, wherein 121 genes were predicted as essential and 20 others as having a partial effect. Transcriptomic profiles of CCBAU45436 were used to evaluate the nitrogen fixation capacity in cultivated versus in wild soybean inoculated with the microsymbiont. The model quantified the nitrogen fixation activities of the strain in these two hosts and predicted a higher nitrogen fixation capacity in cultivated soybean. Our results are consistent with published data demonstrating larger amounts of ureides and total nitrogen in cultivated soybean than in wild soybean. This work presents the first metabolic network reconstruction of S. fredii as an example of a useful tool for exploring the potential benefits of microsymbionts to sustainable agriculture and the ecosystem.IMPORTANCE Nitrogen is the most limiting macronutrient for plant growth, and rhizobia are important bacteria for agriculture because they can fix atmospheric nitrogen and make it available to legumes through the establishment of a symbiotic relationship with their host plants. In this work, we studied the nitrogen fixation process in the microsymbiont Sinorhizobium fredii at the genome level. A metabolic model was built using genome annotation and literature to reconstruct the symbiotic form of S. fredii Genes controlling the nitrogen fixation process were identified by simulating gene knockouts. Additionally, the nitrogen-fixing capacities of S. fredii CCBAU45436 in symbiosis with cultivated and wild soybeans were evaluated. The predictions suggested an outperformance of S. fredii with cultivated soybean, consistent with published experimental evidence. The reconstruction presented here will help to understand and improve nitrogen fixation capabilities of S. fredii and will be beneficial for agriculture by reducing the reliance on fertilizer applications.

The Abundance of Arbuscular Mycorrhiza Infective Propagules Under Galam Stand at Shallow Peat of South Kalimantan

Colonization of arbuscular mycorrhiza on plants has been reported to give benefit to p lants, especially at extreme sites such as degraded peatland. Galam (Mela leuca ca juputi) is an indigenous peatland species which grows on acidic condition. The number of arbuscular mycorrhiza infective propagules is important to be determined concerning the galam regeneration due to its offered benefits that support colonization. This research aims to determine the abundance of arbuscular mycorrhiza infective propagules under galam stand and to describe symbiotic forms of AMF colonization on the roots of galam. The Most Probable Number (MPN) method, wet sieving, and root staining from the modification of Vierherlig et al., 1996, and the calculation of root’s mycorrhizal colonization by grid line technique were the methods that were used in this research. The research used Complete Randomized Design (CRD) with a 5-fold factorial pattern. The results of this study indicated a significant difference between the abundance of AMF under galam stands at the depth of 0-15 cm and 15-30 cm respectively . The results of spores identification showed 4 genera of spores, namely: Glomus, Gigaspora, Scutellospora, and Acaulospora. The structure of root colonizations were hyphae, spores, vesicles, and arbuscular.

Influence of dietary sodium alginate and Pediococcus acidilactici on liver antioxidant status, intestinal lysozyme gene expression, histomorphology, microbiota, and digestive enzymes activity, in Asian sea bass (Lates calcarifer) juveniles

A 42-day study was conducted to determine the effect of incorporating dietary low molecular weight sodium alginate (LMWSA), extracted from the brown algae, Undaria pinnatifida and Macrocystis pyritera, and Pediococcus acidilactici MA 18/5 M (PA), Lallemand Animal Nutrition S.A., Blagnac, France, on growth performance, antioxidant defense activity, intestinal lysozyme gene (LYZ) expression, histo-morphology, microbiota, and digestive enzymes activity of Asian sea bass (Lates calcarifer) juveniles. Six experimental diets were formulated including: Diet (1) a basal diet (Control), Diet (2) 5 g LMWSA kg−1 diet, Diet (3) 10 g LMWSA kg−1 diet, Diet (4) 0.9 × 107 CFU PA g−1 diet, Diet (5) 5 g LMWSA kg−1 diet + 0.9 × 107 CFU PA g−1 diet, and Diet (6) 10 g LMWSA kg−1 diet + 0.9 × 107 CFU PA g−1 diet were fed to Asian sea bass, L. calcarifer (12.0 ± 0.2 g). The results showed that fish fed PA alone (Diet 4) and the combination of both supplements (Diet 5) had the greatest weight gain. Fish fed Diet 6 and those fed Diet 1 (Control) had the highest and lowest villus height, apparent villus surface and crypt depth, respectively. Fish fed diets administered with PA (Diet 4) or synbiotics (Diets 5 and 6) showed higher total viable and lactic acid bacteria counts than all the other groups. The evaluated digestive enzymes activities including total protease, trypsin, lipase, and α-amylase remarkably increased by administration of LMWSA or its combination with PA. Moreover, liver antioxidant enzymes activities including superoxide dismutase, catalase, and Glutathione S-transferase pronouncedly enhanced following the administration of LMWSA or its combination with PA. Supplementing diet with blends of 10 g kg−1 of LMWSA and PA (Diet 6) more pronouncedly enhanced c-type and g-types LYZ expression in comparison with those fed 5 g kg−1 of LMWSA and PA (Diet 5). Based on the results obtained, it can be claimed incorporating diet with LMWSA and PA separately or in symbiotic form had promising results as functional feed additives in juvenile Asian sea bass L. calcarifer.

Description of a new genus and species of Chrysopetalidae (Annelida: Polychaeta) from the NE Atlantic, with some further records of related species

Five chrysopetalid species are reported from samples collected at bathyal depths in three NE Atlantic regions: the Bay of Biscay, the Horseshoe Abyssal Plain and the Gulf of Cadiz. Arichlidon reyssi (Katzmann et al., 1974), Dysponetus caecus (Langerhans, 1880) and D. profundus Böggemann, 2009 are free-living forms found mainly on biogenic substrates (e.g., coral and sunken wood). A brief description and taxonomical remarks are given for each of these species and their geographical distributions and habitat records were updated accordingly. Natsushima bifurcata Miura & Laubier, 1990 and Craseoschema thyasiricola gen. et sp. nov. are symbionts inhabiting the mantle cavity of chemosynthesis-based bivalves known from four mud volcanoes from the Gulf of Cadiz. Craseoschema thyasiricola gen. et sp. nov. was found inside a thyasirid bivalve and presents mixed morphological characteristics of free-living and symbiotic forms within Calamyzinae Hartmann-Schröder, 1971. A full description of the new species is given together with DNA sequences of the genes COI, 16S and H3 that were used in a phylogenetic analysis to indicate the position of the new genus within the family.

Potential survival of the lichen Caloplaca flavovirescens under high helium-beam doses.

Testing the limits of survivability in space is the primary focus in astrobiological research. Although a number of previous studies have examined terrestrial life survival in an extraterrestrial environment, only a few have investigated how life systems respond to high doses of alpha cosmic ray, the main component of cosmic rays. We used respiration and photosynthetic rates as indicators of the vital signs of the lichen Caloplaca flavovirescens, which is a symbiotic life form including fungi and algae. Our experiment demonstrated that the photosynthetic rate decreased with increased helium-beam doses, whereas the respiration rate was relatively unaffected. Specifically, under a helium-beam dose greater than 10Gy, the respiration rate remained nearly constant regardless of further increases in the radiation rate. Our results indicate that the different metabolic systems of terrestrial life forms might exhibit different survival characteristics when they are in space.

Hybrids, Chimeras, Aberrant Nuptials:

The essay examines different cases of bioart, which, by combining biological materials and technological processes, present new forms of biological assemblages. For example, such collectives as Tissue Culture and Art Project and Art Orienté Objet, artists Eduardo Kac, ORLAN, Maja Smrekar and Robertina Šebjanič invent new forms of hybridization and symbiotic forms of cohabitation. The essay will question what is so specific in bioart and in what respect does it differ from scientific research conducted in laboratories, or fromsome biological phenomena found in the natural world. My hypothesis is that bioart introduces a specific mode of bio-performativity and creates a unique moment of bio-presence: it does not represent but presents and produces new material bodies, which are living and decaying in our presence. The essay will seek to discuss the specific time in which these Semi-Living objects perform their existence: this time, which is “the time of the now”, can be called (in Giorgio Agamben’s terms) kairos and contrasted with our habitual chronological time.Kairos is a messianic time, a contraction of time (similar to time in specific laboratory conditions), which helps to imagine new ways of organizing living materials. In this sense, bio-presence and bio-performativity can be seen as a resistance to the habitual arrangement of space and time and its biopolitical implications

Interaction and Regulation of Carbon, Nitrogen, and Phosphorus Metabolisms in Root Nodules of Legumes.

Members of the plant family Leguminosae (Fabaceae) are unique in that they have evolved a symbiotic relationship with rhizobia (a group of soil bacteria that can fix atmospheric nitrogen). Rhizobia infect and form root nodules on their specific host plants before differentiating into bacteroids, the symbiotic form of rhizobia. This complex relationship involves the supply of C4-dicarboxylate and phosphate by the host plants to the microsymbionts that utilize them in the energy-intensive process of fixing atmospheric nitrogen into ammonium, which is in turn made available to the host plants as a source of nitrogen, a macronutrient for growth. Although nitrogen-fixing bacteroids are no longer growing, they are metabolically active. The symbiotic process is complex and tightly regulated by both the host plants and the bacteroids. The metabolic pathways of carbon, nitrogen, and phosphate are heavily regulated in the host plants, as they need to strike a fine balance between satisfying their own needs as well as those of the microsymbionts. A network of transporters for the various metabolites are responsible for the trafficking of these essential molecules between the two partners through the symbiosome membrane (plant-derived membrane surrounding the bacteroid), and these are in turn regulated by various transcription factors that control their expressions under different environmental conditions. Understanding this complex process of symbiotic nitrogen fixation is vital in promoting sustainable agriculture and enhancing soil fertility.

Physiological analysis of growth and nitrogen metabolism of intercropped pasture species subterranean clover (Trifolium subterraneum L.) and cocksfoot (Dactylis glomerata L.) supplemented with different forms of inorganic nitrogen

ABSTRACTGrowth and physiological parameters of intercropped subterranean clover (Trifolium subterraneum L.) and cocksfoot (Dactylis glomerata L.) were investigated under controlled and field conditions. Nitrogen nutrition was accomplished in symbiotic and heterotrophic forms in both the species studied under controlled concentration of mineral elements in the media and by in oculation with appropriate rhizobial strain. Intercropped variants were also grown in sand culture as follows: subterranean clover – 100%, cocksfoot – 100%, subterranean clover:cocksfoot– 75:25(%), subterranean clover: cocksfoot– 50:50(%), and subterranean clover:cocksfoot– 25:75(%). In hydroponic cultures, subterranean clover to cocksfoot proportion was always 50:50(%). Subterranean clover reacted positively with growth up to 1.25 mM nitrate concentration in the medium with stimulation of number of nodules formed and their nitrogenase activity. When separately grown, both subclover and cocksfoot reacted with higher plant biomass formation under higher nitrate nutrition. When intercropped, the process of growth stimulation in subclover was more prominent than in cocksfoot.

ОПТИМІЗАЦІЯ ДІАГНОСТИЧНО-ТЕРАПЕВТИЧНИХ ЗАХОДІВ ПРИ СПОНТАНОМУ І ЗВИКЛОМУ НЕВИНОШУВАННІ ВАГІТНОСТЕЙ В АНАМНЕЗІ АСОЦІЙОВАНИХ З ДИСБІОЗОМ ПІХВИ

Мета дослідження – удосконалення лікувально-профілактичних заходів з метою зниження ранніх втрат вагітності на тлі дисбіозу піхви.Матеріали та методи. З метою оцінки ефективності селективного симбіотика (Lactobacterium Breve BROZ), мікроінвазивної форми прогестерону, фолієвої кислоти, актовегіну і комбінованого препарату, складниками якого є омега-3 поліненасичені жирні кислоти, вітаміни А і D2 та калію йодид, вагітні жінки були розподілені на дві репрезентативні групи: І група – 50 жінок, які склали основну групу; ІІ група – 50 осіб які отримували базисну терапію.Результати дослідження та їх обговорення. Використання селективного симбіотика в поєднанні з мікроінвазивною формою прогестерону, актовегіном, фолієвою кислотою в комплексі з комбінованим препаратом, до складу якого входять: омега-3 поліненасичені жирні кислоти, вітаміни А і D2 та калію йодид природного сполучення, дозволяє навіть після першого курсу терапії відновити мікробіоценоз піхви до нормоценозу у вагітних у І групі в 68,0 % проти 58,0 % – у другій та знизити загрозу переривання вагітності у 2,6 раза, септичні ускладнення в пуерперії – у 2,9 раза, інфекційні ускладнення в неонатальному періоді – в 2,5 раза та ранню неонатальну смертність – у 2,2 раза.Висновок. Запропонована терапія сприяє більш швидкій нормалізації біоценозу секрету піхви та позитивно впливає на наслідки гестаційного процесу, що підтверджено клінічним ефектом.