A New Network Structure for Speech Emotion Recognition Research.

Deep learning promotes the breakthrough of emotion recognition in many fields, especially speech emotion recognition (SER). As an important part of speech emotion recognition, the most relevant acoustic feature extraction has always attracted the attention of existing researchers. Aiming at the problem that the emotional information contained in the current speech signals is distributed dispersedly and cannot comprehensively integrate local and global information, this paper presents a network model based on a gated recurrent unit (GRU) and multi-head attention. We evaluate our proposed emotion model on the IEMOCAP and Emo-DB corpora. The experimental results show that the network model based on Bi-GRU and multi-head attention is significantly better than the traditional network model at detecting multiple evaluation indicators. At the same time, we also apply the model to a speech sentiment analysis task. On the CH-SIMS and MOSI datasets, the model shows excellent generalization performance.

Responses of microbial community to geochemical parameters on vertical depth in bioheap system of low-grade copper sulfide.

Monitoring of the microbial community in bioleaching system is essential for control process parameters and enhance the leaching efficiency. Due to the difficulty of sampling, microbial distribution, community succession and bioleaching activity along the vertical depth of bioleaching heaps remain unresolved. This study investigated the geochemical parameters and microbial community structure along a depth profile in a bioleaching heap and leachate. 80 ore samples at different heap depths and 9 leaching solution samples from three bioheaps of Zijin Copper Mine were collected. Microbial composition, mineral types and geochemical parameters of these samples were analyzed by 16S rRNA high-throughput sequencing and a series of chemical measurement technologies. The results revealed that the pH, Cu, Fe and the total sulfur contents were the major factors shaping the composition of the microbial communities in the bioleaching system. The extent of mineral oxidation increased as the sample depth increases, followed by the increasing of sulfur oxidizers. The abundance of sulfur and iron oxidizers including members of Acidithiobacillus, Sulfobacillus and Acidiferrobacter were significantly higher in the leaching heap than in the leaching solution, meanwhile, they showed strong positive interactions with other members within the same genera and iron oxidizer Leptospirillum and Ferroplasma. Besides, Acidithiobacillus negatively interacted with heterotrophs such as Sphingobium, Exiguobacterium, Brevundimonas and so on. On the contrast, members of Leptospirillum and unclassified Archaea were significantly abundant in the leaching solution and revealed strong interactions with members of Thermoplasmatales. The main conclusion of this study, especially the leaching potential of microorganisms prevailing in bioheaps and their relationships with geochemical factors, provides theoretical guidance for future process design such as the control of processing parameters and microbial community in heap leaching.

Soil microbiomes divergently respond to heavy metals and polycyclic aromatic hydrocarbons in contaminated industrial sites.

Contaminated sites from electronic waste (e-waste) dismantling and coking plants feature high concentrations of heavy metals (HMs) and/or polycyclic aromatic hydrocarbons (PAHs) in soil. Mixed contamination (HMs + PAHs) hinders land reclamation and affects the microbial diversity and function of soil microbiomes. In this study, we analyzed HM and PAH contamination from an e-waste dismantling plant and a coking plant and evaluated the influences of HM and PAH contamination on soil microbiomes. It was noticed that HMs and PAHs were found in all sites, although the major contaminants of the e-waste dismantling plant site were HMs (such as Cu at 5,947.58 ± 433.44 mg kg-1, Zn at 4,961.38 ± 436.51 mg kg-1, and Mn at 2,379.07 ± 227.46 mg kg-1), and the major contaminants of the coking plant site were PAHs (such as fluorene at 11,740.06 ± 620.1 mg kg-1, acenaphthylene at 211.69 ± 7.04 mg kg-1, and pyrene at 183.14 ± 18.89 mg kg-1). The microbiomes (diversity and abundance) of all sites were determined via high-throughput sequencing of 16S rRNA genes, and redundancy analysis was conducted to investigate the relations between soil microbiomes and contaminants. The results showed that the microbiomes of the contaminated sites divergently responded to HMs and PAHs. The abundances of the bacterial genera Sulfuritalea, Pseudomonas, and Sphingobium were positively related to PAHs, while the abundances of the bacterial genera Bryobacter, Nitrospira, and Steroidobacter were positively related to HMs. This study promotes an understanding of how soil microbiomes respond to single and mixed contamination with HMs and PAHs.

Alicyclobacillus curvatus sp. nov. and Alicyclobacillus mengziensis sp. nov., two acidophilic bacteria isolated from acid mine drainage.

Two acidophilic strains, designated as ALEF1T and S30H14T, were isolated from acid mine drainage sediment. Cells of both strains were Gram-stain-positive, aerobic, endospore-forming rods. Strains ALEF1T and S30H14T were acidophilic and mesophilic, the former grew at 20-40 °C (optimum, 30 °C) and pH 2.5-4.5 (optimum, pH 3.5), while the latter grew at 20-45 °C (optimum, 30 °C) and pH 2.0-5.5 (optimum, pH 4.5). The 16S rRNA gene-based sequence analysis revealed that strains ALEF1T and S30H14T belonged to the genus Alicyclobacillus, and were phylogenetically close to Alicyclobacillus ferrooxydans TC-34T with 97.1 and 97.4% similarity, respectively. The similarity between the two novel strains was 98.6 %. The average nucleotide identity value between the genome sequences of ALEF1T and S30H14T was 79.5 %, and that between each of the two isolates and A. ferrooxydans TC-34T were 72.0 and 74.3 %. In addition, the digital DNA-DNA hybridization value between ALEF1T and S30H14T was 24.9 %, between strain ALEF1T and A. ferrooxydans TC-34T was 21.7 %, and between S30H14T and A. ferrooxydans TC-34T was 26.3 %, far below the interspecies threshold. Both strains could utilize diverse carbon sources for heterotrophic growth; strain ALEF1T could utilize ferrous iron as the energy source for autotrophic growth. Menaquinone 7 was the only quinone detected in either strain. Both strains contained anteiso-C15 : 0 and anteiso-C17 : 0, while ω-alicyclic fatty acids were not detected. Based on their phylogenetic positions, as well as phenotypic and genomic data, it is considered that strains ALEF1T and S30H14T represent two novel species within the genus Alicyclobacillus, for which the names Alicyclobacillus curvatus sp. nov. (type strain ALEF1T=CGMCC 1.17055T=KCTC 43124T) and Alicyclobacillus mengziensis sp. nov. (S30H14T=CGMCC 1.17050T=KCTC 43125T) are proposed.

Key Factors Governing Microbial Community in Extremely Acidic Mine Drainage (pH <3).

The microbial community of acid mine drainage (AMD) fascinates researchers by their adaption and roles in shaping the environment. Molecular surveys have recently helped to enhance the understanding of the distribution, adaption strategy, and ecological function of microbial communities in extreme AMD environments. However, the interactions between the environment and microbial community of extremely acidic AMD (pH <3) from different mining areas kept unanswered questions. Here, we measured physicochemical parameters and profiled the microbial community of AMD collected from four mining areas with different mineral types to provide a better understanding of biogeochemical processes within the extremely acidic water environment. The prominent physicochemical differences across the four mining areas were in SO4 2-, metal ions, and temperature, and distinct microbial diversity and community assemblages were also discovered in these areas. Mg2+ and SO4 2- were the predominant factors determining the microbial structure and prevalence of dominant taxa in AMD. Leptospirillum, Ferroplasma, and Acidithiobacillus were abundant but showed different occurrence patterns in AMD from different mining areas. More diverse communities and functional redundancy were identified in AMD of polymetallic mining areas compared with AMD of copper mining areas. Functional prediction revealed iron, sulfur, nitrogen, and carbon metabolisms driven by microorganisms were significantly correlated with Mg2+ and SO4 2-, Ca2+, temperature, and Fe2+, which distinguish microbial communities of copper mine AMD from that of polymetallic mine AMD. In summary, microbial diversity, composition, and metabolic potential were mainly shaped by Mg2+ and SO4 2- concentrations of AMD, suggesting that the substrate concentrations may contribute to the distinct microbiological profiles of AMD from different mining areas. These findings highlight the microbial community structure in extremely acidic AMD forming by types of minerals and the interactions of physicochemical parameters and microbiology, providing more clues of the microbial ecological function and adaptation mechanisms in the extremely acidic environment.

Candidatus Kaistella beijingensis sp. nov., Isolated from a Municipal Wastewater Treatment Plant, Is Involved in Sludge Foaming.

Biological foaming (or biofoaming) is a frequently occurring problem in wastewater treatment plants (WWTPs) and is attributed to the overwhelming growth of filamentous bulking and foaming bacteria (BFB). Biological foaming has been intensively investigated, with BFB like Microthrix and Skermania having been identified from WWTPs and implicated in foaming. Nevertheless, studies are still needed to improve our understanding of the microbial diversity of WWTP biofoams and how microbial activities contribute to foaming. In this study, sludge foaming at the Qinghe WWTP of China was monitored, and sludge foams were investigated using culture-dependent and culture-independent microbiological methods. The foam microbiomes exhibited high abundances of Skermania, Mycobacterium, Flavobacteriales, and Kaistella. A previously unknown bacterium, Candidatus Kaistella beijingensis, was cultivated from foams, its genome was sequenced, and it was phenotypically characterized. Ca. K. beijingensis exhibits hydrophobic cell surfaces, produces extracellular polymeric substances (EPS), and metabolizes lipids. Ca. K. beijingensis abundances were proportional to EPS levels in foams. Several proteins encoded by the Ca. K. beijingensis genome were identified from EPS that was extracted from sludge foams. Ca. K. beijingensis populations accounted for 4 to 6% of the total bacterial populations in sludge foam samples within the Qinghe WWTP, although their abundances were higher in spring than in other seasons. Cooccurrence analysis indicated that Ca. K. beijingensis was not a core node among the WWTP community network, but its abundances were negatively correlated with those of the well-studied BFB Skermania piniformis among cross-season Qinghe WWTP communities. IMPORTANCE Biological foaming, also known as scumming, is a sludge separation problem that has become the subject of major concern for long-term stable activated sludge operation in decades. Biological foaming was considered induced by foaming bacteria. However, the occurrence and deterioration of foaming in many WWTPs are still not completely understood. Cultivation and characterization of the enriched bacteria in foaming are critical to understand their genetic, physiological, phylogenetic, and ecological traits, as well as to improve the understanding of their relationships with foaming and performance of WWTPs.

Mobile genetic elements mediate the mixotrophic evolution of novel Alicyclobacillus species for acid mine drainage adaptation.

Alicyclobacillus species inhabit diverse environments and have adapted to broad ranges of pH and temperature. However, their adaptive evolutions remain elusive, especially regarding the role of mobile genetic elements (MGEs). Here, we characterized the distributions and functions of MGEs in Alicyclobacillus species across five environments, including acid mine drainage (AMD), beverages, hot springs, sediments, and soils. Nine Alicyclobacillus strains were isolated from AMD and possessed larger genome sizes and more genes than those from other environments. Four AMD strains evolved to be mixotrophic and fell into distinctive clusters in phylogenetic tree. Four types of MGEs including genomic island (GI), insertion sequence (IS), prophage, and integrative and conjugative element (ICE) were widely distributed in Alicyclobacillus species. Further, AMD strains did not possess CRISPR-Cas systems, but had more GI, IS, and ICE, as well as more MGE-associated genes involved in the oxidation of iron and sulfide and the resistance of heavy metal and low temperature. These findings highlight the differences in phenotypes and genotypes between strains isolated from AMD and other environments and the important role of MGEs in rapid environment niche expansions.

Casimicrobium huifangae gen. nov., sp. nov., a Ubiquitous "Most-Wanted" Core Bacterial Taxon from Municipal Wastewater Treatment Plants.

Microorganisms in wastewater treatment plants (WWTPs) play a key role in the removal of pollutants from municipal and industrial wastewaters. A recent study estimated that activated sludge from global municipal WWTPs harbors 1 × 109 to 2 × 109 microbial species, the majority of which have not yet been cultivated, and 28 core taxa were identified as "most-wanted" ones (L. Wu, D. Ning, B. Zhang, Y. Li, et al., Nat Microbiol 4:1183-1195, 2019, https://doi.org/10.1038/s41564-019-0426-5). Cultivation and characterization of the "most-wanted" core bacteria are critical to understand their genetic, physiological, phylogenetic, and ecological traits, as well as to improve the performance of WWTPs. In this study, we isolated a bacterial strain, designated SJ-1, that represents a novel cluster within Betaproteobacteria and corresponds to OTU_16 within the 28 core taxa in the "most-wanted" list. Strain SJ-1 was identified and nominated as Casimicrobium huifangae gen. nov., sp. nov., of a novel family, Casimicrobiaceae. C. huifangae is ubiquitously distributed and is metabolically versatile. In addition to mineralizing various carbon sources (including carbohydrates, aromatic compounds, and short-chain fatty acids), C. huifangae is capable of nitrate reduction and phosphorus accumulation. The population of C. huifangae accounted for more than 1% of the bacterial population of the activated sludge microbiome from the Qinghe WWTP, which showed seasonal dynamic changes. Cooccurrence analysis suggested that C. huifangae was an important module hub in the bacterial network of Qinghe WWTP.IMPORTANCE The activated sludge process is the most widely applied biotechnology and is one of the best ecosystems to address microbial ecological principles. Yet, the cultivation of core bacteria and the exploration of their physiology and ecology are limited. In this study, the core and novel bacterial taxon C. huifangae was cultivated and characterized. This study revealed that C. huifangae functioned as an important module hub in the activated sludge microbiome, and it potentially plays an important role in municipal wastewater treatment plants.

[Microbial community structure and function in acid mine drainage from Mengzi, Yunnan Province].

In order to explore the microbial communities and functions in distinct environments of acid mine drainage (AMD) ecosystem and fully comprehend the patterns of AMD formation and development, high-throughput sequencing technology was used to study the prokaryotic community composition in AMD puddles and surrounding rills in a mining area in Mengzi, Yunnan Province, China. By combining with physicochemical properties of the samples, we distinguished the key factors affecting the community structure and analyzed the environmental functions of the microflora. We discovered that the main phyla in AMD puddles were Euryarchaeota, Proteobacteria (including the class α-, γ- and δ-Proteobacteria), Nitrospirae, Firmicutes, Actinobacteria, and Acidobacteria. Community structure of the AMD puddles apparently differed from that of the surrounding rills. Microbial diversity was significantly positively correlated with pH, whereas the relative abundance of Thermoplasmata was negatively correlated with pH and this class might play a predominant role in community structure. There was high relative abundance of the genus Ferroplasma (6.60%-86.34%) in different samples of AMD puddles. Acidithiobacillus spp. were the major iron- and/or sulfur-oxidizing bacteria in AMD solutions and sediments, whereas relative abundance of the obligate iron-oxidizer Leptospirillum spp. was lower, and Ferrovum spp. were almost only present in the AMD solutions. In addition, acidophilic or acid-tolerant heterotrophic bacteria were widely distributed in the AMD solutions and sediments, which might promote the growth of iron- and/or sulfur-oxidizers and catalyze the oxidative/reductive dissolution of metal ores. Our results suggested that pH significantly impacted the microbial community structure of AMD environment by affecting the microbial diversity and microflora distribution.