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C[O.sub.2] emissions from soils were measured under 3 land-use types at the adjacent plots of forest plantation, grassland, and cropland from January 2005 to December 2006. Mean soil C[O.sub.2] efflux rates measured during the 2-year study varied from 59 to 527 mg C[O.sub.2]/[m.sup.2].h in forest plantation, 37 to 498 mg C[O.sub.2]/[m.sup.2].h in grassland, and 32 to 397 mg C[O.sub.2]/[m.sup.2].h in cropland. Soil respiration in the 3 types of land-use showed a similar seasonal pattern in variation during both years, in which the single-peaked curve occurred in early summer and the minimum in winter. In particular, the date of maximum soil C[O.sub.2] efflux rate in cropland occurred about 30 days earlier than in forest and grassland in both 2005 and 2006. The relationship of soil respiration rate (R) with soil temperature (T) and soil moisture (W) fitted well to the equation [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (a, b, c were constants) than other univariate models which consider soil water content or soil temperature alone. Soil temperature and soil moisture together explained 69-92% of the temporal variation in soil respiration in the 3 land-use types. Temperature sensitivity of soil respiration ([Q.sub.10]) was affected positively by soil moisture of top 0.1 m layer and negatively by soil temperature at 0.05 m depth. The relationship between [Q.sub.10] values and soil temperature (T) or soil moisture (W) indicated that a 1°C increase in soil temperature at 0.05 m depth will reduce the [Q.sub.10] value by 0.07, 0.05, and 0.06 in forest, grassland, and cropland, respectively. Similarly, a 1% decrease in soil moisture of the top 0.1 m layer will reduce the [Q.sub.10] value by 0.10, 0.09, and 0.11 in forest, grassland, and cropland. Additional keywords: soil respiration, [Q.sub.10] value, soil temperature, soil moisture., Introduction As an important component of terrestrial carbon cycling, soil respiration has received considerable attention in recent years because of the release of large quantities of C[O.sub.2] from the soils [...]

Two Artemia culture experiments were conducted in a zero water exchange system at salinity 80 g L−1. In Experiment I, different carbon sources including molasses, glucose, sucrose and corn flour were given to supplement suboptimal feeding with the microalgae Dunaliella viridis, whereas the control was fed only D. viridis. In Experiment II, molasses was supplemented to the culture medium, as well as the bacteria Alkalibacterium sp. or the archaea Halobacterium sp., isolated from the brine in the local saltponds. The control groups were fed only with D. viridis or with D. viridis and molasses. Our study shows that in laboratory culture biofloc development can be stimulated under hypersaline conditions. Supplementation of carbon sources, bacteria and archaea benefited biofloc development, water quality in terms of nitrogen load and enhanced Artemia production. Denaturing gradient gel electrophoresis analysis on the bioflocs also indicates an increased biodiversity and richness of the microbial community in the culture medium. These results need to be confirmed for large scale Artemia pond production, in which case, we recommend molasses as carbon source. [ABSTRACT FROM AUTHOR]

Penicillium decumbens has been used in the industrial production of lignocellulolytic enzymes in China for more than 15 years. Conidiation is essential for most industrial fungi because conidia are used as starters in the first step of fermentation. To investigate the mechanism of conidiation in P. decumbens, we generated mutants defective in two central regulators of conidiation, FluG and BrlA. Deletion of fluG resulted in neither “fluffy” phenotype nor alteration in conidiation, indicating possible different upstream mechanisms activating brlA between P. decumbens and Aspergillus nidulans. Deletion of brlA completely blocked conidiation. Further investigation of brlA expression in different media (nutrient-rich or nutrient-poor) and different culture states (liquid or solid) showed that brlA expression is required but not sufficient for conidiation. The brlA deletion strain exhibited altered hyphal morphology with more branches. Genome-wide expression profiling identified BrlA-dependent genes in P. decumbens, including genes previously reported to be involved in conidiation as well as previously reported chitin synthase genes and acid protease gene ( pepB). The expression levels of seven secondary metabolism gene clusters (from a total of 28 clusters) were drastically regulated in the brlA deletion strain, including a downregulated cluster putatively involved in the biosynthesis of the mycotoxins roquefortine C and meleagrin. In addition, the expression levels of most cellulase genes were upregulated in the brlA deletion strain detected by real-time quantitative PCR. The brlA deletion strain also exhibited an 89.1 % increase in cellulase activity compared with the wild-type strain. The results showed that BrlA in P. decumbens not only has a key role in regulating conidiation, but it also regulates secondary metabolism extensively as well as the expression of cellulase genes. [ABSTRACT FROM AUTHOR]

Abstract: Terrestrial carbon sequestration involves a series of processes, including photosynthesis, plant autotrophic respiration and soil microbial heterotrophic respiration. Field measurements of carbon dioxide (CO2) using either eddy covariance or chamber methods usually provide bulk CO2 fluxes from more than one sink or source. For the purpose of estimating the C budget in ecosystems, it is inherently important to determine the individual sinks or sources. This report describes how we tested the Forest-DNDC model using a dataset collected at a subtropical forest site in Sichuan Province, China. One-year field measurements were conducted using a chamber method at four plots with different treatments that were specifically designed to distinguish the CO2 fluxes produced from three sources: root respiration, forest floor respiration and mineral soil respiration. The obtained datasets were utilized to verify the modeled CO2 fluxes from the corresponding sources for the tested forest ecosystem. Results from the tests indicated that Forest-DNDC was capable not only of quantifying the total CO2 emissions but also of distinguishing their sources related to plant autotrophic and soil microbial heterotrophic respiration. Because measuring root respiration is always difficult in field investigations, adopting Forest-DNDC for quantifying root respiration represents an appropriate complement to most field measurements. [Copyright &y& Elsevier]

Viburnum japonicum is a rare plant species and endemic to the coastal region of Eastern Asia with extremely small populations. Within mainland China, this species can be only found in narrow habitats of the northeast coastal islands of Zhejiang Province. However, there are scarce conservation genetic studies on V. japonicum , which has limited the effective conservation and management of this rare species. Here, 51 individuals in four natural populations covering the Chinese geographic range of the species were sampled to assess the genetic diversity and population structure. A total of 445,060 high-quality single nucleotide polymorphisms (SNPs) were identified using double digest restriction-site associated sequencing (ddRAD-seq). The overall average values of observed heterozygosity ( Ho ), expected heterozygosity ( He ), and average nucleotide diversity ( π ), were 0.2207, 0.2595, and 0.2741, respectively. The DFS-2 population exhibited the highest level of genetic diversity among all the populations. Genetic differentiation between populations was moderate ( F ST = 0.1425), and there was selfing between populations ( F IS = 0.1390, S = 24.52%). Of the total genetic variation, 52.9% was found among populations through AMOVA analysis. The Mantel test ( r = 0.982, p = 0.030) combined with analyses of the Maximum Likelihood (ML) phylogenetic tree, ADMIXTURE, and principal component analysis (PCA), revealed that populations of V. japonicum were genetically segregated and significantly correlated with their geographical distribution. Our study demonstrated that V. japonicum maintained a medium level of genetic diversity and differentiation with a strong population structure, and the results were mainly affected by its island distribution pattern and self-crossing characteristics. These results provide insights into the genetic diversity and population history of V. japonicum , critical information for conserving and sustainably developing its genetic resources., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Zhu, Liu, Gao, Yue and Li.)

The shikimate pathway serves an essential role in many organisms. Not only are the three aromatic amino acids synthesized through this pathway, but many secondary metabolites also derive from it. Decades of effort have been invested into engineering Saccharomyces cerevisiae to produce shikimate and its derivatives. In addition to the ability to express cytochrome P450, S. cerevisiae is generally recognized as safe for producing compounds with nutraceutical and pharmaceutical applications. However, the intrinsically complicated regulations involved in central metabolism and the low precursor availability in S. cerevisiae has limited production levels. Here we report the development of a new platform based on Scheffersomyces stipitis, whose superior xylose utilization efficiency makes it particularly suited to produce the shikimate group of compounds. Shikimate was produced at 3.11 g/L, representing the highest level among shikimate pathway products in yeasts. Our work represents a new exploration toward expanding the current collection of microbial factories.

The distribution of DTPA-Zn was influenced by other zinc forms in soil profile. In order to approach the mechanism of zinc deficiency in calcareous purple soil widely distributed in hilly regions of central Sichuan Province, four profiles(paddy field, dry land, K1c forest land and J3p forest land) under different land use were selected to study the distribution of other zinc forms. The results indicated that the distribution complication of zinc forms was in order of paddy field > dry land > forest land. The quantities of CAB-Zn(3.65%), TOM-Zn(2.81%) and COFe-Zn(22.04%) in farmland were evidently more than those (1.86%, 0.84%, 11.59%) in paddy field.