Recent Adopted

The influence mechanism of land development intensity of Beijing-Tianjin-Hebei agglomeration from a perspective of administrative spatial spillover effect

WANG PENGRUI , ZENG CHEN

Adopted date: July 17,2024

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Abstract:
In recent years, the spatial non-integration effect of administrative regions and economic zones existed in China, and as an important means of spatial governance, territorial spatial planning is the important foundation for the high-quality development of cross-regional. The research area is Beijing-Tianjin-Hebei agglomeration, explores the spatio-temporal change and driving mechanism of land development intensity, and embeded the adjacency relationship between county-level administrative units into the spatial econometric model to explore the influence mechanism of land development intensity under the different scenarios of administrative spatial spillover effect. The results show that the land development intensity of different county-level administrative unites were quite different in the Beijing-Tianjin-Hebei agglomeration, and the spatio-temporal differentiation and spatial agglomeration was significantly. The land development intensity of most county-level administrative units in the Beijing-Tianjin-Hebei agglomeration were improved, but the spatial pattern of "high in the southeast and low in the northwest" has not change. Population density, the proportion of tertiary industry added value and per capita GDP had significant effects on the land development intensity. The spatial distribution of land development intensity has significant positive spatial correlation, and the direct spatial spillover effect is obvious. From 2010 to 2019, the administrative spatial spillover effect of different adjacent relationships were different, and the spillover of adjacent relationships of different types of county-level administrative units was enhanced. In the future , we should make full use of the spillover effect of administrative space of land development intensity to achieve the sustainable development.

Changes in enzyme activity, nutritional components and antioxidant activity of Lentinula edodes stalk substrate during the solid-state fermentation of Poria cocos

Yu Qingsong , Chen Yuxia , Hu Guoyuan , Ma Xinlong

Adopted date: July 13,2024

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Abstract:
Abstract In order to investigate whether the mycelia of Poria cocos can ferment and utilize Lentinula edodes stalk substrate and improve its nutritional value and biological activity. P. cocos was cultured on the solid medium using L. edodes stalk as the sole substrate. The kinetic changes of enzyme activities, nutrient composition and antioxidant activity were measured. The results showed that the cellulose exonuclease activity reached 46.14 U/g on the 6th day of the fermentation process, subsequently decreased rapidly to 17.15 U/g, and remained essentially unchanged on the 18th day. The activity of carboxymethyl cellulase and xylanase reached 77.70 U/g and 74.23 U/g, respectively, on the 12th days of fermentation and then gradually decreased. The β-glucosidase activity reached 75.06 U/g on the 18th of the fermentation and then gradually decreased. In comparison with the unfermented L. edodes stalk substrate, total sugar, soluble protein and insoluble dietary fiber of fermented L. edodes stalk substrate showed significant decrease, whereas the contents of reducing sugar, polysaccharidecontents, total phenols, total flavone, amino nitrogen and soluble dietary fiber were increased obviously. The antioxidant capacity of water extracts of fermentation substrate was significantly improved as well. The DPPH radical scavenging rate and the hydroxyl radical scavenging rate increased by 97.75% and 38.15% respectively. The results showed that P. cocos could fermet L. edodes stalk, alter the nutritional components of L. edodes stalk, and that the fermentation substrate exhibited enhanced free radical scavenging ability.

Analysis on the structure of bacterial microbial community in wet heartwood of Populus dehoides in the Jianghan Plain

Zhou Jing Yu , Huang Guo Wei , Zhang Ya Dong , Qi Gao Fu , Zhang Xin Ye

Adopted date: July 13,2024

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Abstract:
In order to investigate the role of bacterial microbial communities in the pathogenesis of poplar wet heartwood, the wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. ‘Huashi2’ were studied, and high-throughput sequencing of the V5-V7 region of the 16S rRNA gene was used to sequence and analyze the bacteria informatically. Principal component analysis, α-diversity index analysis and microbial network analysis techniques were used to explore the differences in the structure and composition of the bacterial microbial communities in the wet heartwood and normal timber of 6-year-old poplar. The results showed that:At the genus level of the bacterial microbial community of 6-year-old Populus deltoides Bartr. ‘Huashi2’ wet heartwood and normal timber, the highest bacterial abundance was found in the genera of Ralstonia and Bacteroides, and the genera of Bacteroides , Pleomorphomonas and Hydrogenispora accounted for a significantly higher proportion of the wet heartwood than that of the normal timber ( p<0.05). Functional analysis of microbial communities showed that Ralstonia were mostly phytopathogenic bacteria, which widely existed in wet heartwood. Analysis of the alpha diversity index showed that wet heartwood community diversity and species distribution evenness were higher than that of normal wood, and the total number of species was lower than that of normal wood.. Co-occurrence network study showed that there were more competition and antagonism among bacterial microorganisms in poplar normal timber, and the community was more unstable, while the bacterial microbial community in wet heartwood was more stable. The analysis of key microorganisms showed that the key bacterial microorganisms in the wet heartwood of 6-year-old poplar were Aquabacterium, WCHB1-32, etc., and the key bacterial microorganisms in the normal heartwood of 6-year-old poplar were Pleomorphomonas, Dysgonomonas, etc. These key microorganisms play an important role in stabilizing the microbial network structure of wet heartwood. In this study, we found that poplar wet heartwood formation is influenced by multiple factors and results from the joint action of microbial communities.

Review the Mechanisms of Bacterial Adhesion in the Rhizosphere Interface

Yanzhao Chen , Shulin Xu , Chenchen Qu , Ming Zhang , Chunhui Gao , Yichao Wu , Ke Dai , Qiaoyun Huang , Peng Cai

Adopted date: July 13,2024

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Abstract:
Interfacial interactions form the foundation for bacterial adhesion, colonization, biofilm formation, and control the ecological function of bacteria in the environment. Meanwhile, the processes also play a crucial role in nutrient absorption and against pathogenic microorganisms by plants. Research on microbe-plant rhizosphere interactions has predominantly studied from the ecological and molecular biological perspectives, employing various omics techniques to study the effects of root exudates on the quantity, community composition, and physiological functions of rhizosphere microorganisms. However, the physical and chemical interfacial mechanisms involved in bacterial colonization have been overlooked. This review explores the mechanisms of interfacial interactions, discussing the regulatory effects of different types of root exudates on bacterial surface properties, extracellular polymeric substances (EPS) molecular composition, and their adhesion functions. Furthermore, the research methods related to the dynamics, structure, and energy of rhizosphere bacterial adhesion and the research frontiers, such as rhizosphere biomolecular characterization, adhesion functionality of these biomolecules, and in situ observation methods were summarized. Interfacial regulation is a key approach for the targeted selection of rhizosphere microorganisms. Advancing our knowledge of the molecular mechanisms of microbial rhizosphere adhesion can help us better use of beneficial microbes in agriculture and develop more effective bio-organic fertilizers.

Efficient solid-phase microextraction tubes used for on-site sampling of trace polycyclic aromatic hydrocarbons in environmental water

ZHENG Meijie , HUANG Yu , LI Xiujuan

Adopted date: July 12,2024

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Abstract:
In order to realize on-site sampling of trace pollutants in environmental water, a large-capacity solid-phase microextraction (SPME) tube was developed, and an on-site SPME sampling device was constructed. The performance of the SPME tube and the on-site SPME device was evaluated using gas chromatography-flame ionization detector for the analysis of phthalates and polycyclic aromatic hydrocarbons (PAHs). Results show that the extraction performance of the tube is stable and reproducible, and the sampling device is flexible to be assembled and easy to carry. The detection limits obtained by the on-site SPME device with 3 SPME tubes were 0.01~0.04 ng/L, which were 6~14 times higher than that of a single SPME tube, and 36~53 times higher than that of the SPME fiber. The recoveries were 92.0%~115.7% and the relative standard deviations were 1.5%~13.1% at different spiking levels. The device has a strong enrichment capacity, and can be flexibly constructed and automated, which can be used for efficient monitoring of different pollutants in environmental water.

Research Progress on the Microbial Synthesis of Gamma-aminobutyric Acid

Wang Shiyi , Zhao Yiwen , Jia Tianli , Chen Shouwen

Adopted date: July 09,2024

[Abstract](39) [HTML](0) [PDF 0.00 Byte](0)

Abstract:
Gamma-aminobutyric acid (GABA) is a four carbon, non-protein amino acid with widely application prospects in food, agriculture, medicine, chemical and other fields. The production of GABA through microbial synthesis has been gaining increasing attention due to its mildness and sustainable development advantages. Therefore, in order to achieve an environmentally, convenient, and more efficient metabolic production pathway for GABA that meets the stringent requirements for additives in the food, pharmaceutical, and livestock industries, the main synthesis pathways of GABA and the research progress of microbial synthesis of GABA are introduced systematically, and the future research directions and development trends are prospected.

Comparison of quality differences in the preparation of high-temperature Daqu using synthetic microbial communities replacing traditional Muqu

GUO Xiaolong , DENG Can , ZHANG Mingchun , GAO Ruijie , LIU Pulin , ZHANG Enhua , LIANG Xiaotong , YU Li , XIONG Lijun , MIAO Lihong

Adopted date: July 08,2024

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Abstract:
Using wheat as raw material, Bacillus licheniformis BL44, Saccharomyces cerevisiae SCY62, Paecilomyces variotii PV3, Rhizomucor pusillus RP1 and Thermoascus crustaceus TC1, which were isolated and screened from the high-temperature Daqu, were prepared into a solid agent and two synthetic microbial communities were constructed according to different addition ratios. The synthetic microbial community was used to replace the traditional Muqu (CK) to make high-temperature Daqu and carry out comparative laboratory brewing experiments. High-throughput sequencing results revealed that the dominant fungal genus of the three kinds of Daqu was Lichtheimia, and the dominant bacterial genus was Bacillus. The results of physicochemical indexes of the Daqu showed that the liquefaction and saccharification abilities of the high-temperature Daqu inoculated with the synthetic microbial communities were significantly improved compared to CK. The results of gas chromatography-mass spectrometry analysis showed that there were 69 types of volatile compounds produced by artificially synthesized microbial communities in Daqu, which was higher than the 68 types inoculated with traditional Muqu. In addition, inoculating artificial synthetic microbial communities instead of traditional Muqu can significantly increase the content of tetramethylpyrazine in Daqu and fermented grains. The content of tetramethylpyrazine in Daqu inoculated with artificial synthetic microbial group 1 and microbial group 2 were 31903.5 μg/kg and 56733.6 μg/kg respectively, increased by 2.80 and 4.99 times respectively compared to CK. In the high-temperature stacked fermentation mash, the content of tetramethylpyrazine inoculated with artificial synthetic bacterial group 1 and bacterial group 2 were 755.8 μg/kg and 2741.4 μg/kg respectively, increased by 4.03 and 14.61 times respectively compared to CK. This study provides a certain theoretical basis for the application of synthetic microbial community in Daqu.

Progress and prospects on studying beneficial interactions between algae and bacteria in aquatic environments

Wu xinyan , Li Xin , Yu Jie , Zhao Na , Zhang Xu , Xie Bo

Adopted date: July 07,2024

[Abstract](27) [HTML](0) [PDF 0.00 Byte](0)

Abstract:
Algae and bacteria play important roles in the biogeochemical cycle, energy flows of important elements in the ecosystem. Some bacteria can have beneficial interactions with algae by promoting the growth of algae and helping algae resist stress, thereby having important impacts on the survival, competition, and physiological functions of both partners. This article reviewed the main ways of interaction, microbial communities, molecular mechanisms, and the recent applications of beneficial interactions between algae and bacteria in the treatment of environmental pollution, biomass energy, and synthetic biology to in-depth study the beneficial interactions between algae and bacteria. The studies on the beneficial interactions between algae and bacteria were prospected. It will not only play an important role in understanding the structure and function of microbial community in aquatic environments, and the mechanisms and effects of relationships among microbial species, but also provide important scientific basis for maintaining the health of ecosystems, mining and utilizing the biological resources for the benefit of humanity.

Predation mechanism and application prospect of bdellovibrio-and-like organisms (BALOs)

陈雯莉 , Tan Shuxin , Huang Qiaoyun

Adopted date: July 07,2024

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Abstract:
The specialist predator bacteria bdellovibrio-and-like organisms (BALOs) are highly valued for their potential applications in agriculture, industry and medicine, especially in the treatment of antibiotic-resistant pathogenic bacterial infections. However, many basic scientific questions about BALOs have been unclear in the past decades, which is the fundamental reason why this type of bacteria has not been effectively developed and utilized for the time being. Recently, many progresses have been made concerning their life cycle, predation mechanisms, resource distribution and diversity, and their applications in medicine, agriculture, or industry. Especially since the formal establishment of the phylum Bdellovibrionota in 2021, there has been an explosive growth in related research. This review will systematically review the previous advances of BALOs and highlight the recently reported outstanding achievements, such as the study of predation mechanism, to promote the understanding and further applications of the resources of BALOs and to guide the future research on BALOs.

Research on cooperative control of sinking and floating motion of mariculture cage

Han Hao , Xia Yingkai , Li Jiawei , Wu Zhe , Guo Zhengjiang

Adopted date: July 05,2024

[Abstract](19) [HTML](0) [PDF 0.00 Byte](0)

Abstract:
Sinking and floating motion control is an important means to improve the quality of mariculture cages and ensure the safety of aquaculture. However, it is difficult to achieve accurate sinking and floating control due to multiple factors such as complex sea conditions and uneven loads. Aiming at the problem of sinking and floating control of a mariculture cage, this paper carries out modeling and collaborative control strategy research. Firstly, based on the analysis of the characteristics of cage structure, actuator and other objects, the dynamic model of sinking and floating is established. Secondly, based on the principle of parallel drive, a double closed-loop master-slave cooperative cage sinking and floating motion control strategy is proposed : the outer loop realizes the cooperative water inflow planning of multi-ballast tanks based on PID master-slave synchronization strategy ; the inner loop designs an efficient water inlet controller based on fuzzy sliding mode control and Lyapunov theory. Finally, through multi-condition digital simulation, the ballast tank water control algorithm and the cage sinking and floating cooperative motion control scheme are verified. The research results show that the control algorithm proposed in this paper can realize efficient water inflow control of ballast tanks, and can achieve high-precision sinking-floating coordinated control under different wave disturbances, which can provide technical support for practical applications.

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