Winter is a long period of the annual cycle of many lakes in the northern hemisphere. Low irradiance, ice, and snow cover cause poor light penetration into the water column of these lakes. Therefore, in northern lakes, respiration often exceeds primary production leading to low dissolved oxygen concentrations. This study aimed to quantify under‐ice metabolic processes during winter in an arid zone lake with little snow cover. This study was carried out in a mid‐latitude lake in Inner Mongolia, northern China. The study lake receives relatively high incoming solar radiation on the ice in mid‐winter, and radiation can penetrate down to the bottom sediment as the lake is shallow and the ice lacks snow cover. Primary production and respiration were estimated during two winters using high‐frequency sensor measurements of dissolved oxygen. To quantify under‐ice metabolic processes, sensors were deployed to different depths. During both winters, sensors collected data every 10 min over several weeks. The amount of solar radiation controlled photosynthesis under ice; temperature and photosynthesis together appeared to control respiration. The balance between gross primary production and ecosystem respiration was especially sensitive to changes in snow cover, and the balance between P and R decreased. Our data suggest that photosynthesis by plankton, submerged plants, and epiphytic algae may continue over winter in shallow lakes in mid‐latitudes when there is no snow cover on the ice, as may occur in arid climates. The continuation of photosynthesis under ice buffers against dissolved oxygen depletion and prevents consequent harmful ecosystem effects.

A total of 22 novel stilbene derivatives containing the 1,3,4-oxadiazole moiety and trimethoxybenzene were designed and synthesized. Their chemical structures were characterized by (1)H and (13)C nuclear magnetic resonance, infrared, and high-resolution mass spectrometry. Bioassay results revealed that some of the title compounds showed potent in vivo fungicidal activities against three phytopathogenic fungi (Pseudoperonospora cubensis, Colletotrichum lagenarium, and Septoria cucurbitacearum) from cucurbits at 600 μg/mL. Notably, compounds 4b, 4d, 4i, 4k, and 4l exhibited a broad spectrum and remarkably high activities against those fungi, some of which even showed a comparable control efficacy to that of the commercial fungicides. Three-dimensional quantitative structure-activity relationship based on comparative molecular field analysis with good predictive ability (q(2) = 0.516; r(2) = 0.920) was reasonably discussed. For the first time, the present work suggested that the stilbene derivatives containing the 1,3,4-oxadiazole moiety could be developed as potential fungicides for crop protection.

A lysogenic phage, MZTP02, was produced via induction by mitomycin C from Bacillus thuringiensis (B. thuringiensis) strain MZ1. Plaques were about 3 mm in diameter with a small inner zone consisting of new B. thuringiensis colonies. Electron microscopic analysis showed that MZTP02 had a long tail (220 nm x 18 nm) and an icosahedral head (82 nm x 85 nm). MZTP02 was insensitive to organic solvents such as chloroform, and infected six B. thuringiensis strains. Its complete genome contained 15,717 base pairs (bp) with 37.55% G + C content. Two inverted terminal repeats consisting of 40 bp were 65% identical. Twenty putative open reading frames (ORFs) were found in the MZTP02 genome, and nine predicted proteins, including two terminase subunits, portal protein, minor head protein, scaffold protein, two putative membrane proteins, tail component, and minor structural protein, showed similarity to other phage proteins. But six ORFs were unique. The presence of a terminal protein at the 5'-terminus was demonstrated using proteinase K, lambda exonuclease and E. coli exonuclease III to digest the genome DNA. A TMP phylogenetic tree was constructed based on amino acid sequences from ten phages.

More than half of the world's lakes are seasonally ice-covered (Verpoorter et al., 2014). A large fraction of lakes are located between 60° and 66°N, where the annual ice season lasts more than 150 days (Leppäranta, 2015). An ice and snow covered lake is remarkably different than one with an open water surface with respect to the optical, thermal, and mechanical properties. Freezing of lakes brings a divergent seasonal aquatic environment compared with the open-water period in terms of lake physics, chemistry, and ecology. For instance, the lake ice cover largely reduces the solar radiation into the water body, keeps the water body cold, and shelters the water body from atmospheric deposition and wind stirring, weakening, or even ceasing the hydrodynamics (Kirillin et al., 2012). These physical changes can drive or facilitate the migration and transformation of nutrients and metals (

Gray mold, caused by Botrytis cinerea, is one of the most destructive fungal diseases in crops, responsible for significant economic losses. In search of natural product-based fungicides, we designed and synthesized a series of novel 3,4dichlorophenyl isoxazole-substituted stilbene derivatives, and their in vivo antifungal activities against B. cinerea were evaluated. The results indicated that some of the target molecules demonstrated remarkable efficiency for the control of tomato gray mold. In particular, compound 5r displayed the highest fungicidal potency with an inhibition rate of 56.11% comparable to that of positive control boscalid (66.96%). Moreover, a hologram quantitative structure−activity relationship (HQSAR) model with good predictive capability was developed to provide in-depth insight into the activity profiles of these compounds. Preliminary mechanism studies suggested that compound 5r might exert its antifungal effect by changing hyphal morphology and increasing the membrane permeability. The present study contributes to the development of natural stilbene derivatives as alternative bioactive agents against B. cinerea.