Effects of Microbial Organic Fertilizer (MOF) Application on Desert Soil Enzyme Activity and Jujube Yield and Quality

Developing effective regulatory strategies to enhance irrigation water and fertilizer efficiency in the southern Xinjiang region of China, while simultaneously combatting desertification, is of paramount significance. This study focuses on Chinese jujube in Xinjiang and presents findings from a two-year field experiment aimed at investigating the optimal application strategy of microbial organic fertilizer (MOF). The research aims to provide a scientific foundation for achieving high-quality jujube production. The experiment involved a control group (utilizing only freshwater, referred to as CK) and various combinations of MOF treatments. In 2021, these treatments included M1 (0.6 t/ha), M2 (1.2 t/ha), M3 (1.8 t/ha), and M4 (2.4 t/ha), while in 2022, they encompassed M1 (0.6 t/ha), M2 (1.2 t/ha), M4 (2.4 t/ha), and M5 (4.8 t/ha). Over the two-year trial period, we assessed various indices, including the soil’s physical properties, hydraulic characteristics, soil enzyme activities, and relative chlorophyll content. Additionally, we evaluated jujube yield, quality, and economic benefits. The results indicate that MOF application led to significant improvements in soil conditions. Specifically, the average moisture content and profile water storage of the 0–50 cm soil layer increased by 10.98% to 36.42% and 1.8% to 26.8%, respectively. Moreover, in both the 2021 and 2022 experiments, soil saturated water content (SSWC) and water-holding capacity (WHC) increased by 6.25% to 15.98%, while soil hydraulic conductivity (Ks) and bulk density (BD) decreased by 2.91% to 9.88% and 0.63% to 8.08%, respectively. In 2021, MOF application resulted in significant enhancements in soil enzyme activities, with urease activity increasing by approximately 22.5% to 100.5%, peroxidase activity rising by around 24.2% to 148.5%, and invertase activity augmenting by about 5.4% to 32.9%. Notably, the M4 treatment in 2021 demonstrated a substantial jujube yield increase of approximately 19.22%, elevating from 7.65 t/ha to 9.12 t/ha. Based on comprehensive analysis, this study recommends an optimal MOF application rate of approximately 2.4 t/ha. This approach not only provides robust support for the sustainable development of the jujube industry but also serves as a valuable reference for enhancing local soil resilience against desertification

Realization of broadband polarization-insensitive negative refraction using water-based metamaterial

We propose a water-based metamaterial to realize the broadband polarization insensitive negative refraction. The designed metamaterial exhibits the multiple resonances in broadband region and displays negative permittivity and permeability simultaneously with a broadband negative refractive index. Simulated result shows that two separated wide bandwidths of negative refractive index are formed at 12.5–22.7 GHz, and 26.2–28.0 GHz, and the relative bandwidths of which are 58.0%, and 6.7%, respectively. In addition, beam shifting simulation is carried out to verify the retrieved effective refractive index from the scatter parameters, and the calculated results based on beam shifting simulation are agreed well with the retrieved effective refractive indices. Finally, the microwave measurement is performed to exam the simulated and calculated results, and three results of simulation, calculation, and measurement are consistent with each other. The design using water-based metamaterial provides an alternative approach to realize a broadband negative refraction

Insight into Dominant Cellulolytic Bacteria from Two Biogas Digesters and Their Glycoside Hydrolase Genes

<div><p>Diverse cellulolytic bacteria are essential for maintaining high lignocellulose degradation ability in biogas digesters. However, little was known about functional genes and gene clusters of dominant cellulolytic bacteria in biogas digesters. This is the foundation to understand lignocellulose degradation mechanisms of biogas digesters and apply these gene resource for optimizing biofuel production. A combination of metagenomic and 16S rRNA gene clone library methods was used to investigate the dominant cellulolytic bacteria and their glycoside hydrolase (GH) genes in two biogas digesters. The 16S rRNA gene analysis revealed that the dominant cellulolytic bacteria were strains closely related to <i>Clostridium straminisolvens</i> and an uncultured cellulolytic bacterium designated BG-1. To recover GH genes from cellulolytic bacteria in general, and BG-1 in particular, a refined assembly approach developed in this study was used to assemble GH genes from metagenomic reads; 163 GH-containing contigs ≥ 1 kb in length were obtained. Six recovered GH5 genes that were expressed in <i>E</i>. <i>coli</i> demonstrated multiple lignocellulase activities and one had high mannanase activity (1255 U/mg). Eleven fosmid clones harboring the recovered GH-containing contigs were sequenced and assembled into 10 fosmid contigs. The composition of GH genes in the 163 assembled metagenomic contigs and 10 fosmid contigs indicated that diverse GHs and lignocellulose degradation mechanisms were present in the biogas digesters. In particular, a small portion of BG-1 genome information was recovered by PhyloPythiaS analysis. The lignocellulase gene clusters in BG-1 suggested that it might use a possible novel lignocellulose degradation mechanism to efficiently degrade lignocellulose. Dominant cellulolytic bacteria of biogas digester possess diverse GH genes, not only in sequences but also in their functions, which may be applied for production of biofuel in the future.</p></div

A systematic study of the whole genome sequence of Amycolatopsis methanolica strain 239T provides an insight into its physiological and taxonomic properties which correlate with its position in the genus

The complete genome of methanol-utilizing Amycolatopsis methanolica strain 239T was generated, revealing a single 7,237,391 nucleotide circular chromosome with 7074 annotated protein-coding sequences (CDSs). Comparative analyses against the complete genome sequences of Amycolatopsis japonica strain MG417-CF17T, Amycolatopsis mediterranei strain U32 and Amycolatopsis orientalis strain HCCB10007 revealed a broad spectrum of genomic structures, including various genome sizes, core/quasi-core/non-core configurations and different kinds of episomes. Although polyketide synthase gene clusters were absent from the A. methanolica genome, 12 gene clusters related to the biosynthesis of other specialized (secondary) metabolites were identified. Complete pathways attributable to the facultative methylotrophic physiology of A. methanolica strain 239T, including both the mdo/mscR encoded methanol oxidation and the hps/hpi encoded formaldehyde assimilation via the ribulose monophosphate cycle, were identified together with evidence that the latter might be the result of horizontal gene transfer. Phylogenetic analyses based on 16S rDNA or orthologues of AMETH_3452, a novel actinobacterial class-specific conserved gene against 62 or 18 Amycolatopsis type strains, respectively, revealed three major phyletic lineages, namely the mesophilic or moderately thermophilic A. orientalis subclade (AOS), the mesophilic Amycolatopsis taiwanensis subclade (ATS) and the thermophilic A. methanolica subclade (AMS). The distinct growth temperatures of members of the subclades correlated with corresponding genetic variations in their encoded compatible solutes. This study shows the value of integrating conventional taxonomic with whole genome sequence data

The characterization of six GH5 genes expressed in <i>E</i>.<i>coli</i>.

<p>¹Nearest neighbor represented nearest protein sequence for each GH5 genes.</p><p>²All activity assays were performed at pH7.4 and 50°C. The substrates used to determine activities of endoglucanase, mannanase, xylanase and exocellulase were CMC, locust bean gum, xylan (beechwood) and pNPC. The unit of enzyme activity is U/mg protein.</p><p>³Activity was not detected.</p><p>⁴Activity was less than 1 U/mg protein.</p><p>⁵Cel5 and Cel6 were also mentioned as man1 and en2 in elsewhere (Yan <i>et al</i>., 2013), but were not expressed before.</p><p>The characterization of six GH5 genes expressed in <i>E</i>.<i>coli</i>.</p

The hypothetical lignocellulose degradation mechanism predicted from gene 34 to gene 61 in contig FC1 of BG-1.

<p>The 28 genes were predicted to encode two LacI family transcriptional regulators (purple), one GntR family transcriptional regulator (purple), PAS fold and methyl-accepting chemotaxis protein (light green), proteins of four different ABC transport system (green), six GHs (2GH5, Cel5 and Cel6; one GH9; one GH8; 2 GH2, GH2_1 and GH2_2) (red) and other functional proteins. The chemotaxis-like regulatory system described in the black box was inferred from other BG-1 genome information.</p

The number of metagenomic reads and contigs assigned to different GH family.

<p>(a) The number of metagenomic reads assigned to the encoding genes of different GH family. (b) The number of contigs recovered from the metagenomic short reads by the refined assembly approach assigned to the encoding genes of different GH family. U1, U2 and U3 refer to unclassified α-L-arabinofuranosidase, unclassified xylosidase and unclassified α-amylase, respectively.</p

The most dominant OTUs and their compositions in the bacterial 16S rRNA gene clone libraries and metagenomes of Z7 and Z8.

<p>¹The identity of 16S rRNA genes between representative sequence of each dominant OTU and their nearest bacteria or type strains.</p><p>²Z7_PCR and Z8_PCR represent the proportion of each OTU in the 16S rRNA gene clone library of Z7 and Z8.</p><p>³Z7_META and Z8_META represent the proportion of each OTU in all the 16S rRNA genes recovered from Z7 and Z8 metagenomic data.</p><p>* Significant differential OTUs between Z7 and Z8 16S rRNA clone libraries were identified and filtered (q-value, <0.001) using STAMP (permutation test).</p><p>The most dominant OTUs and their compositions in the bacterial 16S rRNA gene clone libraries and metagenomes of Z7 and Z8.</p

Selected carbohydrate-active gene modules detected in the fungus-cultivating termite gut metagenome.

*<p>The carbohydrate-active enzymes database (CAZy), <a href="http://www.CAZy.org" target="_blank">http://www.CAZy.org</a>.</p>§<p>Known CAZy activities were given according to the CAZy database.</p>†<p>Carbohydrate-active enzymes were detected with the set of CAZy family-specific HMMs defined by Yin et al <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069184#pone.0069184-Yin1" target="_blank">[24]</a>, as deposited on dbCAN (<a href="http://csbl.bmb.uga.edu/dbCAN/" target="_blank">http://csbl.bmb.uga.edu/dbCAN/</a>), in the BLAST searches (E≤10⁻⁴). All identified CAZymes were listed in Table S2. Besides, searches for GHs-associated domains were also performed and indexed in Table S3.</p