Abstract As the core microorganism of wine making, Saccharomyces cerevisiae encounter low pH stress at the beginning of fermentation. Effect of initial pH (4.50, 3.00, 2.75, 2.50) on growth and fermentation performance of 3 S. cerevisiae strains Freddo, BH8, Nº.7303, different tolerance at low pH, chosen from 12 strains, was studied. The values of yeast growth (OD 600 , colony forming units, cell dry weight), fermentation efficiency (accumulated mass loss, change of total sugar concentration), and fermentation products (ethanol, glycerol, acetic acid, and l ‐succinic acid) at different pH stress were measured. The results showed that the initial pH of must was a vital factor influencing yeast growth and alcoholic fermentation. Among the 3 strains, strain Freddo and BH8 were more tolerant than Nº.7303, so they were affected slighter than the latter. Among the 4 pH values, all the 3 strains showed adaptation even at pH 2.50; pH 2.75 and 2.50 had more vital effect on yeast growth and fermentation products in contrast with pH 4.50 and 3.00. In general, low initial pH showed the properties of prolonging yeast lag phase, affecting accumulated mass loss, changing the consumption rate of total sugar, increasing final content of acetic acid and glycerol, and decreasing final content of ethanol and l ‐ succinic acid, except some special cases. Based on this study, the effect of low pH on wine products would be better understood and the tolerance mechanism of low pH of S. cerevisiae could be better explored in future.
In this study, we report the effects of hydroxypropyl methylcellulose (HPMC) and KH2PO4 on the water resistance of magnesium oxychloride cement (MOC), a novel bone cement composite. Different MOC samples were soaked in simulated body fluid (SBF). After soaking for 7–56 d, the surfaces of the experimental group (1 wt.% HPMC/2 wt.% KH2PO4-MOC) and control group (2 wt.% KH2PO4-MOC) appeared pores, which grew with increasing immersion time. Compared with the control group, the experimental group had smaller pore sizes and a denser surface. Furthermore, the compressive strength in the experimental group increased from 35.1 ± 1.9 MPa to 41.8 ± 2.3 MPa, and the softening coefficient increased from 0.34 to 0.45. Thus, HPMC could improve the water erosion resistance of the MOC. The implantation study of the femoral defects in rats showed that the sample modified by 1 wt.% HPMC/2 wt.% KH2PO4 had good biocompatibility and biodegradability. The results indicate that the modification of MOC with HPMC and KH2PO4 is a promising technique to form biodegradable bone repair materials and has good application prospects in the field of biomedical materials.
Fusarium root and stem rot in sweetpotato are prevalent in the main sweetpotato-growing areas in China, and fungal isolation, morphological characteristics, and molecular phylogenetic analysis of the disease causal agent ( F. solani-melongenae isolate CRI 24-3) were systematically studied. The genome sequence of F. solani-melongenae isolates CRI 24-3 was first reported, which should provide a basis for genome assembly of other closely related Fusarium species.
Generalized feed-forward Gaussian models have achieved significant progress in sparse-view 3D reconstruction by leveraging prior knowledge from large multi-view datasets. However, these models often struggle to represent high-frequency details due to the limited number of Gaussians. While the densification strategy used in per-scene 3D Gaussian splatting (3D-GS) optimization can be adapted to the feed-forward models, it may not be ideally suited for generalized scenarios. In this paper, we propose Generative Densification, an efficient and generalizable method to densify Gaussians generated by feed-forward models. Unlike the 3D-GS densification strategy, which iteratively splits and clones raw Gaussian parameters, our method up-samples feature representations from the feed-forward models and generates their corresponding fine Gaussians in a single forward pass, leveraging the embedded prior knowledge for enhanced generalization. Experimental results on both object-level and scene-level reconstruction tasks demonstrate that our method outperforms state-of-the-art approaches with comparable or smaller model sizes, achieving notable improvements in representing fine details.
Viruses play a regulatory role in microbial ecology. Traditional fermented foods have complex fermentation environments with abundant viral participation, yet current research on viral communities in fermented foods remains insufficient. Traditional, manually produced solid-state fermented vinegar serves as an excellent model for studying the role of viral communities in fermented foods. Using metagenomic approaches, this study investigates the structure and dynamics of viral communities during the acetic acid fermentation process of Shanxi aged vinegar. All identified viruses were bacteriophages, and the dominant families were identified as Herelleviridae, Autographiviridae, and Stanwilliamsviridae. The richness and diversity of viral communities exhibited significant variations during acetic acid fermentation. Furthermore, correlation analysis revealed a strong association (p < 0.01) between core bacteria and core viruses. Functional annotation revealed the presence of viral genes associated with amino acid and carbohydrate metabolism. Notably, abundant auxiliary carbohydrate-active enzyme (CAZyme) genes were identified in viruses, with glycoside hydrolases (GHs), glycosyltransferases (GTs), and carbohydrate-binding modules (CBMs) demonstrating particularly high abundance. Additionally, several antibiotic resistance genes were detected in viruses. This study elucidates the impact of viral communities on microbial dynamics during food fermentation, advancing our understanding of viral roles in traditional fermented food ecosystems.
