Symbiogenesis Research Articles

Viruses and Evolution

The role of viruses within Big History is an important field in understanding the process of evolution; however, it is not yet extensively studied. This is due both to the fact that viruses, being microscopic pathogenic, have left limited physical traces in the geological record, and because there is no firm agreement on the place of viruses in evolution. The purpose of this report is to explore the role of viruses in the context of evolutionary development within the framework of Big History. It aims to provide an overview of current perspectives and challenges associated with understanding the position of viruses in the broader narrative of evolutionary history. According to a dictionary, a virus is defined as ‘any of a large group of submicroscopic infectious agents that are usually regarded as non-living extremely complex molecules. The term ‘agents’ is commonly used in virology due to the difficulty in finding a universal term to describe these unique entities. A virus is not an organism, in our usual sense of the definition, nor is it a chemical compound since viruses have an overly complex structure and behavior that sets them apart. In the field of evolution, viruses pose a perplexing puzzle piece that does not neatly fit into the larger picture. Undeniably, viruses are the most pervasive entities on Earth. However, despite their ubiquitous presence, only a little over 6,000 virus species have been comprehensively described in the existing body of knowledge. In the paper, the author observes evolution and their origins, including regressive, protobiont hypotheses, as well as the symbiotic theory, which according to some researchers was the factor that led to the three cellular domains of life that we now know. The paper also delves into a fascinating aspect of evolution: the unique position of viruses, which exist on the edge of disorder, displaying high instability yet remarkable adaptability. This raises the question of whether viruses can be considered alive or not, leading to an intriguing debate. We also explore the question of whether viruses can be classified as parasites, which may seem simple at first glance but is actually a complex and contradictory topic. The author discusses the role of viruses from an energetic perspective, recognizing their significance in information and energy dynamics within ecosystems. Viruses exert a substantial influence on energy flows in intricate ecological systems. The paper considers viruses from the perspective of information evolution, because in some respects viruses can be regarded as pure information particles. The author also argues that viruses can be considered as basic information agents that transmit genetic information and are thus the basic molecular tool of evolution. Moreover, this tool is beginning to be used by humans for the genetic alteration of many organisms, including ourselves. It is important that viruses will no longer be considered only as dangerous pathogens, since pathogenic viruses make up only a small part of their genus. We argue that breakthroughs in virology in the coming decades could be no less important as a breakthrough in understanding the nature of bacteria, both pathogenic and beneficial. The paper also examines viruses as a complex self-regulating system drawing comparisons to other complex systems such as computer viruses, cancer, and languages. It emphasizes the remarkable similarities between these systems and explores possible explanations for these similarities.

A strategy of building a beautiful and harmonious countryside: Reuse of idle rural residential land based on symbiosis theory

In most of China's rural areas, there lies in a misallocation conflict between abundance of idle rural residential land (IRRL) and the scarcity of land used for the construction of beautiful and harmonious countryside (CBHC). It's a key challenge to effectively utilize and allocate these idle construction land resources to promote CBHC. This study developed a theoretical framework employing symbiosis theory to establish symbiotic system among multiple rural stakeholders, applied the selection principle of symbiotic interface to create the criteria for the IRRL reuse, and selected one IRRL to verify the construction strategy of public spaces. Using Silong village in Chongqing as a case study, the study unveiled the process and allocation mechanisms governing IRRL reuse from a patch-level perspective. The findings demonstrate that: (1) rural multi-subjects can use IRRL as a symbiotic interface to foster symbiotic relationships; (2) 26.92% and 73.08% of IRRL were allocated to public space and industrial land, respectively; (3) 57.14% of the IRRL for public space can serve residents across multiple village groups; and (4) retaining the original landscape pattern, enhancing infrastructure and incorporating local culture elements are principles for reusing IRRL in the development of public spaces. This study holds significant theoretical and practical implications for advancing CBHC, contributing to the United Nations Sustainable Development Goals (SDGs) and providing a Chinese sample for other developing countries worldwide.

Plastid translocon recycling in dinoflagellates demonstrates the portability of complex plastids between hosts

The plastids of photosynthetic organisms on land are predominantly "primary plastids," derived from an ancient endosymbiosis of a cyanobacterium. Conversely, the plastids of marine photosynthetic organisms were mostly gained through subsequent endosymbioses of photosynthetic eukaryotes generating so-called "complex plastids." The plastids of the major eukaryotic lineages-cryptophytes, haptophytes, ochrophytes, dinoflagellates, and apicomplexans-were posited to derive from a single secondary endosymbiosis of a red alga in the "chromalveloate" hypothesis. Subsequent phylogenetic resolution of eukaryotes has shown that separate events of plastid acquisition must have occurred to account for this distribution of plastids. However, the number of such events and the donor organisms for the new plastid endosymbioses are still not resolved. A perceived bottleneck of endosymbiotic plastid gain is the development of protein targeting from the hosts into the new plastids, and this supposition has often driven hypotheses toward minimizing the number of plastid-gain events to explain plastid distribution in eukaryotes. But how plastid-protein-targeting is established for new endosymbionts is often unclear, which makes it difficult to assess the likelihood of plastid transfers between lineages. Here, we show that Kareniaceae dinoflagellates, which possess complex plastids known to be derived from haptophytes, acquired all the necessary protein import machinery from these haptophytes. Furthermore, cryo-electron tomography revealed that no additional membranes were added to the Kareniaceae complex plastid during serial endosymbiosis, suggesting that the haptophyte-derived import processes were sufficient. Our analyses suggest that complex red plastids are preadapted for horizontal transmission, potentially explaining their widespread distribution in algal diversity.

Organelle and transcriptomic genomes of a freshwater brown alga and further insights on the phylogenetic relationship of red secondary plastid-derived lineages

Freshwater brown algae have been acknowledged as the least diverse of all groups of freshwater algae. Morphological and molecular investigation were conducted on a freshwater brown alga collected in this study. Morphological characterization and phylogenetic tree based on the rbcL gene confirmed its attribution to Heribaudiella fluviatilis. The complete organelle genomes of H. fluviatilis were determined and assembled from high-throughput sequencing. A circular tetrad structure of 128,880 bp was identified for the chloroplast, and the mitochondrial genome was assembled as a circle with 43,657 bp in length. This study provides the first and only record of organelle genomic information of the freshwater Phaeophyceae, which are important for understanding the endosymbiosis theories. Concatenated (Bayesian inference, maximum likelihood under MFP and GHOST models) and coalescent methods were used to construct the phylogenetic relationship among secondary plastid-bearing lineages based on organelle genomes. Obvious conflicts were observed in grouping relationships of chloroplast and mitochondrial genomes, even among different evolutionary models and tree-constructing methods. The transcriptome of H. fluviatilis was sequenced and used to construct the phylogenetic relationship among secondary plastid-bearing lineages. The phylogenetic relationships in nuclear and mitochondrial genomes were consistent in grouping CHSR taxa (cryptophytes, haptophytes, stramenopiles and rhizarians) in an independent branch. The phylogenetic relationship constructed from nuclear transcriptomes was highly reliable by owning robust supporting values on each node and was consistent with the serial endosymbiosis theory on evolution of red secondary plastid-derived lineages.

Novel Framework for Exploring Human–Water Symbiosis Relationship: Analysis, Quantification, Discrimination, and Attribution

There is an interdependent symbiotic relationship between humans and water; scientific and effective assessment of the human–water symbiosis relationship is of great significance for the promotion of sustainable development. This study developed a novel framework of the human–water symbiosis relationship under an integrated perspective, which included theoretical interpretation, quantitative assessment, pattern discrimination, and an attribution analysis. Based on the symbiosis theory, the theoretical analysis of the human–water relationship was carried out to analyze the three basic elements of the human–water system, and then the evaluation index system of the human–water symbiosis system was constructed to quantitatively assess the development level of the human system and the water system. The Lotka–Volterra model was used to identify the symbiotic pattern, and the human–water symbiosis index was calculated to characterize the health state of the human–water symbiosis system. The main influencing factors of the human–water symbiosis system were further identified through an attribution analysis. Finally, a case study was carried out with 18 cities in Henan Province. Results reveal that (a) the proposed method can effectively realize the quantitative characterization of the human–water symbiosis relationship, with good applicability and obvious advantages; (b) the human–water symbiosis pattern of cities in Henan Province is dominated by the “human system parasitizes water system (H+W−)” pattern, and more attention should be paid to the water system in the subsequent development of it; and (c) the main factors influencing the human system, the water system, and the human–water symbiosis system are the research and development (R&D) personnel equivalent full-time (H7), per capita water resources (W1), and proportion of water conservancy and ecological water conservancy construction investment (W6), respectively. The findings can provide theoretical and methodological support for the study of the human–water symbiosis relationship and sustainable development in other regions.

Development Path of Macao Tourism Symbiosis Integration from the Configuration Perspective

The concept of symbiotic and integrated development represents the adaptive response of Macao tourism to the necessity of diversified development. It is the inevitable path for Macao tourism to achieve high-quality sustainable development. In accordance with the principles of the symbiosis theory, this paper presents an analytical framework and employs Qualitative Comparative Analysis (QCA) to examine the intricate causal processes that simultaneously influence the symbiosis integration development of Macao tourism. The results of the empirical test demonstrate that: (1) The development of Macao tourism symbiosis and integration is influenced by five factors: external policy (EP), regional integration (RI), new digital technology (DT), gaming industry (GI), and cultural element (CE); (2) There are three configuration paths for Macao’s tourism symbiosis, integration, and high-quality development, including an industrial synergy mode, innovation-leading mode, and value-sharing mode; (3) There are two configuration paths formed by the non-high-quality symbiotic integration of Macao tourism, namely, the government absence type and the market failure type; (4) RI and GI are the core conditions for the symbiotic and integrated development of Macao tourism, and there is a certain substitution relationship between EP, DT, and CE. This study advances the academic understanding of the asymmetric causal relationship between various factors and the symbiotic integration of tourism. It enhances the application of the symbiotic theory in the practise of tourism and reveals differences in the path of Macao tourism development under the combination of multiple factors. The findings provide a theoretical basis for the Macao government to optimise the tourism spatial layout and enhance tourism sustainability, build a multi-level “tourism+” symbiotic industrial structure, and establish a modern tourism governance system.

The Influence of Local Cultural Factors on the Development of Pingxiang Spring Gongs - Based on the Perspective of Symbiosis Theory

As an important factor in the development of spring gongs in Pingxiang, Jiangxi Province, local cultural factors play an increasingly important role in the symbiosis theory environment. In order to deeply study the influence of local cultural factors on the development of Pingxiang spring gongs, the article divides the local cultural factors into geographic environment, historical background, folk tradition and so on. Based on the perspective of symbiosis theory, the influence of local cultural factors on the development of Pingxiang spring gongs in Jiangxi Province is analyzed theoretically, and local cultural symbiosis is added as a mediating variable, a theoretical model is constructed according to the assumptions, and the following conclusions are drawn from the qualitative and quantitative research by taking Pingxiang spring gongs in Jiangxi Province as the object of the study and applying questionnaire survey method, fieldwork method, in-depth interview method, etc.: the local language, folklore and customs, and local cultural identity have a significant impact on the development level of Pingxiang spring gongs, and this impact is realized through local cultural heritage and development as a mediating variable. In the course of the research, we will pay attention to the key variables of local cultural identity, artistic performance, symbiotic relationship and sustainable development, aiming to provide useful references for the inheritance and development of Pingxiang spring gongs.

Creating and sustaining mutualistic well-being: Toward a theory of family and business symbiosis

This paper addresses a question that is fundamental to the domain of family business research yet still inadequately addressed by the field’s predominant theories: Why are some family business systems able to create and sustain the simultaneous health of both the business and the family over generations, whereas many others experience an erosion in the well-being of one sphere relative to the other? Invoking analogical theorizing, we demonstrate the fruitfulness of applying key concepts from biological research on symbiotic relationships between organisms of different species. More specifically, we suggest that the area’s distinction between mutualism, commensalism, and parasitism provides a useful vocabulary for conceptualizing the heterogeneity evident amongst family business systems. By delineating factors that are likely to influence the nature and strength of a family business system’s symbiotic relationship, we hope that our conceptual framework helps guide future research on why, when, and how the interdependence between family and business can range—and sometimes shift—along a continuum from strong mutualism to strong parasitism.

Forum: Debating the Chinese School(s) of IR Theory

Abstract The papers in this Forum, along with eight papers consecutively published in previous and current issues of this journal, constitute a special symposium, which engages in a dialogue between the “Chinese School” of International Relations (IR) theory and “Western” IR theories. The contributors are renowned Western theorists representing various Western paradigms and leading Chinese theorists from the three branches of the Chinese School, namely “moral realism,” “relational theory,” and “symbiosis theory.” The dialogue between the Chinese School and Western theories has become feasible due to recent theoretical breakthroughs achieved by the former and the observed efforts to enhance theoretical diversity in the latter. Contributors from both sides are committed to fostering an equal, comprehensive, and constructive dialogue. Western theorists provide an evaluation of the Chinese School as a whole and delve into the specifics of its branches. They compare the Chinese School with Western theories, highlighting similarities and differences, reflecting on shared issues, identifying both contributions and shortcomings of the Chinese School, and proposing solutions for its further development. In response, Chinese School scholars reiterate their theoretical concerns and refine their theoretical stances accordingly. This dialogue demonstrates the potential for Chinese and Western theorists to overcome language and cultural barriers to achieve mutual understanding and valuable collaboration.

The Significance of Evolutionary Concepts in Biology for the Formation of Evolutionary and Ecological Thinking

This article is devoted to the philosophical analysis of the theoretical and methodological foundations of evolutionary and ecological thinking. The conceptual development of such thinking is a crucial direction in the advancement of modern life sciences. However, within the foundations of evolutionary and ecological interpretation across various biological fields, contradictions between evolutionary and ecological approaches are explicitly evident. This situation arises because the ecological approach views humans as an active factor in the evolution of their environment while simultaneously assuming their natural immutability, i.e., considering them the pinnacle of evolution. The author attempts to identify the principles for selecting evolutionary theories and concepts that underpin the formation of evolutionary and ecological thinking. In this context, the author addresses various branches of evolutionism, such as classical Darwinism, the synthetic theory of evolution, nomogenesis, autogenesis, orthogenesis, catastrophism, neo-Lamarckism, Autopoietic Theory, mutual aid, and symbiosis in evolution. The conclusion is drawn that effective evolutionary and ecological thinking cannot rely solely on the biological characteristics of evolutionism but requires a philosophical understanding of the cultural and historical status of humans in the world.

Evaluation of Urban–Rural Total Factor Flow Efficiency Based on Multiple Symbiosis: Insights from 27 Provinces in China

The rational flow of production factors is crucial for promoting benign interactions between urban and rural areas. To unveil the intrinsic mechanisms of factor flow pathways promoting mutual symbiosis between urban and rural areas, this study, based on symbiosis theory, takes total factor flow including land, technology, capital, and labor as inputs and urban–rural symbiosis level as output. Utilizing the Super-Efficiency Slack-Based Measure (SBM) model, this study calculates the urban–rural total factor flow efficiency of 27 provinces in China from 2011 to 2021 and explores specific improvement directions of urban–rural factor flow based on projection analysis. This study revealed the following findings: (1) The overall efficiency of urban–rural total factor flow in China shows a fluctuating upward trend but has not yet reached an effective state. There are significant regional disparities, with 8 provinces such as Guangdong and Fujian reaching Pareto optimality, while the remaining 19 provinces exhibit varying degrees of inefficiency. (2) Provinces with insufficient symbiotic production are mainly concentrated in the central and western regions and the northeast region, with 14 provinces including Inner Mongolia showing the inadequate transformation of urban–rural symbiosis. However, except for Hainan, the situation is gradually improving in other regions annually. (3) There is input redundancy in total factor, where land, labor, and capital redundancy are the main reasons for the inefficiency of urban–rural total factor flow in China. However, trends show that the redundancy of land, labor, and capital elements is improving annually, while technology redundancy is worsening. (4) Through a comprehensive analysis of input redundancy, output deficiency, symbiosis coefficient, and efficiency, this study categorizes the impact of factor flow on urban–rural symbiosis level into basic matching, redundancy, and comprehensive scarcity types. The research provides scientific guidance for promoting sustainable development through the rational flow of total factors and offers valuable insights for similar countries.

Drug Repurposing of Selected Antibiotics: An Emerging Approach in Cancer Drug Discovery.

Drug repurposing is a method of investigating new therapeutic applications for previously approved medications. This repurposing approach to "old" medications is now highly efficient, simple to arrange, and cost-effective and poses little risk of failure in treating a variety of disorders, including cancer. Drug repurposing for cancer therapy is currently a key topic of study. It is a way of exploring recent therapeutic applications for already-existing drugs. Theoretically, the repurposing strategy has various advantages over the recognized challenges of creating new molecular entities, including being faster, safer, easier, and less expensive. In the real world, several medications have been repurposed, including aspirin, metformin, and chloroquine. However, doctors and scientists address numerous challenges when repurposing drugs, such as the fact that most drugs are not cost-effective and are resistant to bacteria. So the goal of this review is to gather information regarding repurposing pharmaceuticals to make them more cost-effective and harder for bacteria to resist. Cancer patients are more susceptible to bacterial infections. Due to their weak immune systems, antibiotics help protect them from a variety of infectious diseases. Although antibiotics are not immune boosters, they do benefit the defense system by killing bacteria and slowing the growth of cancer cells. Their use also increases the therapeutic efficacy and helps avoid recurrence. Of late, antibiotics have been repurposed as potent anticancer agents because of the evolutionary relationship between the prokaryotic genome and mitochondrial DNA of eukaryotes. Anticancer antibiotics that prevent cancer cells from growing by interfering with their DNA and blocking growth of promoters, which include anthracyclines, daunorubicin, epirubicin, mitoxantrone, doxorubicin, and idarubicin, are another type of FDA-approved antibiotics used to treat cancer. According to the endosymbiotic hypothesis, prokaryotes and eukaryotes are thought to have an evolutionary relationship. Hence, in this study, we are trying to explore antibiotics that are necessary for treating diseases, including cancer, helping people reduce deaths associated with various infections, and substantially extending people's life expectancy and quality of life.

Functional Characterization of the First Bona Fide Phytoene Synthase in Red Algae from Pyropia yezoensis.

The formation of phytoene by condensing two geranylgeranyl diphosphate molecules catalyzed by phytoene synthase (PSY) is the first committed and rate-limiting step in carotenoid biosynthesis, which has been extensively investigated in bacteria, land plants and microalgae. However, this step in macroalgae remains unknown. In the present study, a gene encoding putative phytoene synthase was cloned from the economic red alga Pyropia yezoensis-a species that has long been used in food and pharmaceuticals. The conservative motifs/domains and the tertiary structure predicted using bioinformatic tools suggested that the cloned PyPSY should encode a phytoene synthase; this was empirically confirmed by pigment complementation in E. coli. This phytoene synthase was encoded by a single copy gene, whose expression was presumably regulated by many factors. The phylogenetic relationship of PSYs from different organisms suggested that red algae are probably the progeny of primary endosymbiosis and plastid donors of secondary endosymbiosis.

The role of the "gut microbiota-mitochondria" crosstalk in the pathogenesis of multiple sclerosis.

Multiple Sclerosis (MS) is a neurologic autoimmune disease whose exact pathophysiologic mechanisms remain to be elucidated. Recent studies have shown that the onset and progression of MS are associated with dysbiosis of the gut microbiota. Similarly, a large body of evidence suggests that mitochondrial dysfunction may also have a significant impact on the development of MS. Endosymbiotic theory has found that human mitochondria are microbial in origin and share similar biological characteristics with the gut microbiota. Therefore, gut microbiota and mitochondrial function crosstalk are relevant in the development of MS. However, the relationship between gut microbiota and mitochondrial function in the development of MS is not fully understood. Therefore, by synthesizing previous relevant literature, this paper focuses on the changes in gut microbiota and metabolite composition in the development of MS and the possible mechanisms of the crosstalk between gut microbiota and mitochondrial function in the progression of MS, to provide new therapeutic approaches for the prevention or reduction of MS based on this crosstalk.

The Chinese School of IR Theory: Ignored Process, Controversial Progress, and Uncertain Prospects

Abstract This article reviews issues relevant to the Chinese School of International Relations (IR) theory. After 20 or more years of relentless effort, the Chinese School has achieved concrete breakthroughs, evident in the emergence of Relational Theory, Moral Realism, and Symbiosis Theory. The Chinese School has thus entered a new stage, its primary task having been upgraded from theory innovation to theory development. But to proceed further, the Chinese School needs critical responses from its Western counterparts. Owing primarily to the language barrier, as well as to the non-confrontational academic tradition within Chinese IR, and the ethnocentrism that both sides practice, the few dialogues that have taken place between the Chinese School and Western theories have tended to be problematic, with important issues either ignored or misrepresented. In order to further study a comprehensive and intensive exchange of ideas between the Chinese School and Western theories, this article categorises issues relevant to the Chinese School into three areas. They are: process of evolution; progress in theoretical studies; and the Chinese School’s future relationship with other theoretical entities (in particular, Global IR). Predominantly reliant upon the discourse analysis of Chinese School publications, this contribution seeks to provide a foundation for further exchanges between Western theories and the Chinese School.

Multi-group symbiotic evolutionary mechanisms of a digital innovation ecosystem: Numerical simulation and case study.

In the digital innovation ecosystem, the symbiosis mode formed between ecosystem members not only relates to their survival and development but also affects the ecosystem's symbiosis evolution mechanism. Based on symbiosis theory, this study first explores the evolutionary equilibrium strategy and its stability for three types of populations-core enterprises, digital platforms, and university research institutes-and then uses numerical simulation and a case study to explore the symbiotic evolution mechanism of the digital innovation ecosystem. The results show that: First, the digital innovation ecosystem is a complex adaptive system in which the three types of populations form different symbiotic relationships under different symbiotic modes and conduct symbiotic activities, such as value co-creation, to characterize the unique symbiotic evolutionary structure. Second, in this ecosystem, the symbiotic relationship formed by the combined values of different symbiotic coefficients between populations determines the outcome of symbiotic evolution. Third, the ideal direction of the evolution of the digital innovation ecosystem is a mutually beneficial symbiotic relationship. Thus, the symbiotic relationship between populations should be transformed into a mutually beneficial symbiotic relationships as much as possible. This study makes theoretical contributions by shedding light on the symbiotic evolution mechanism of the digital innovation ecosystem. It also offers countermeasures for the digital innovation cooperation of various stakeholders in China's digital innovation ecosystem.

New plastids, old proteins: repeated endosymbiotic acquisitions in kareniacean dinoflagellates

Dinoflagellates are a diverse group of ecologically significant micro-eukaryotes that can serve as a model system for plastid symbiogenesis due to their susceptibility to plastid loss and replacement via serial endosymbiosis. Kareniaceae harbor fucoxanthin-pigmented plastids instead of the ancestral peridinin-pigmented ones and support them with a diverse range of nucleus-encoded plastid-targeted proteins originating from the haptophyte endosymbiont, dinoflagellate host, and/or lateral gene transfers (LGT). Here, we present predicted plastid proteomes from seven distantly related kareniaceans in three genera (Karenia, Karlodinium, and Takayama) and analyze their evolutionary patterns using automated tree building and sorting. We project a relatively limited ( ~ 10%) haptophyte signal pointing towards a shared origin in the family Chrysochromulinaceae. Our data establish significant variations in the functional distributions of these signals, emphasizing the importance of micro-evolutionary processes in shaping the chimeric proteomes. Analysis of plastid genome sequences recontextualizes these results by a striking finding the extant kareniacean plastids are in fact not all of the same origin, as two of the studied species (Karlodinium armiger, Takayama helix) possess plastids from different haptophyte orders than the rest.

Symbiosis Evolution of Regional Knowledge Innovation Ecosystem: The Relevance of Lotka–Volterra Model

Knowledge innovation is the driving force and guarantee of regional development. Inspired by population ecology, this article uses symbiosis theory to explore the symbiotic relationship of subjects in the regional knowledge innovation ecosystem. The nonlinear Lotka–Volterra model is constructed with the main subjects to measure the knowledge innovation ability of knowledge innovation subjects. The symbiotic relationships among the knowledge innovation subjects in each region are identified. Taking Beijing, Shanghai, and Guangzhou as examples, a sensitivity analysis of the initial value and coopetition relationship is conducted. The results show that the initial value change has no significant effect on the development of knowledge innovation subjects. The interaction relationships among subjects directly affect the symbiotic evolution trend. The study extends the application scope of the symbiosis theory and develops a theoretical framework for the development of subjects in regional knowledge innovation ecosystem. It offers regions a reference to use Lotka–Volterra model adjusting the knowledge innovation structure in various regions.

Evaluation of regional integration in urban agglomeration area from the perspective of urban symbiosis

Integrated development of urban agglomeration is a process involves both interactive elements flow between cities and cohesive function advancement within each city. However, existing researches struggle to effectively evaluate urban integration considering both urban interaction and urban function. Taking Yunnan Central urban agglomeration (CYUA) as a case study, we adopt the framework of symbiosis theory to analyze integrated degree of urban agglomeration by combining urban interaction and function. Urban vitality, urban spilled function, intermediate intervention of urban interaction, urban functional distance were detected to identify urban symbiotic modes and project into evaluating urban integration. The results show that, (1) focus on the symbiotic environment, a spatial pattern of “one core and multiple weak” is exhibited, the key role of downtown Kunming is obviously identified; (2) focus on the symbiotic modes, suboptimal condition of urban symbiosis is observable based on the dominant symbiotic mode and its dynamic; (3) CYUA is still in the embryonic stage of integration. To mature the urban agglomeration, more attention should be paid on strengthening urban interaction by constructing interactive channel, adjusting urban function by analyzing regional industrial link, and finally improving urban symbiotic mode based on the optimization of symbiotic environment and interface.

Exploring Integrative Development of Urban Agglomeration from the Perspective of Urban Symbiosis and Production–Living–Ecological Function

Integrative development is an effective way to enhance urban potential and implement resource-optimal relocation, especially in urban agglomeration regions. Conventionally, the evaluation of urban integration is usually studied from one aspect of urban interaction intensity or urban functional similarity, but considering both together can better reflect the integrative condition of urban agglomeration. This paper introduces the symbiosis theory into the exploration of urban integration. The production–living–ecological function is taken to analyze urban function, and the improved radiation model is adopted to measure urban interaction. Under the framework of symbiosis theory, we integrate urban function and urban interaction to indicate the integrative condition of urban agglomeration from a production–living–ecological aspect. Urban agglomeration in the Central Yunnan Urban Agglomeration is taken as the study area. The results show that (1) spatial variations occur in high-value areas with distinct functions. The east emphasizes production and living, while the west leans towards ecology. (2) Urban agglomeration is in its early developmental stages without stable symbiosis. Interactions among counties mostly show sporadic point symbiosis, lacking stability. It mainly radiates outward from the central area, with more stable interactions in high-value areas, often causing inter-city competition. (3) Urban agglomeration integration is generally low, with distinct high-value production and ecological areas. The central, eastern, and southern regions exhibit strong production and living interactions, while the west benefits from ecological interactions. These findings can offer some insights for informing relevant policies and fostering the integrated development of urban agglomerations.