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Spatiotemporal image fusion enables the generation of time-series high spatial resolution (HR) images for monitoring fine-scale land surface dynamics, particularly for long-term (including historical) changes. Despite remarkable improvements, current spatiotemporal fusion methods still face challenges in accurately predicting complex land-cover changes. This article proposes a spatiotemporal image fusion model enhanced by spectrally preserved pre-prediction (PreSTFM) to improve the accuracy of land-cover change detection and reconstruction. The temporary pre-predicted HR image achieves a high level of spectral fidelity, specifically for land-cover changes, by introducing a multiband spectral mapping approach. Moreover, the pre-prediction plays a crucial role in establishing land-cover change-based constraint conditions to address the issue of incorrect similar pixels found in weighting-based methods. In addition to land-cover changes, PreSTFM can ensure that predicted changes align more accurately with actual changes (also including phenological changes) occurring in the landscape owing to spectrally preserved pre-prediction and spatial filtering mechanisms. The proposed PreSTFM was tested using three time-series Landsat and Moderate-Resolution Imaging Spectroradiometer (MODIS) datasets, compared with a flexible spatiotemporal data fusion (FSDAF) model and a robust adaptive spatial and temporal fusion model (RASTFM). The results indicate that PreSTFM outperforms FSDAF and RASTFM, yielding a root-mean-square error (RMSE) reduction of 6.1%–22.7% and 10.4%–27.5%, respectively. In addition, the PreSTFM predictions visually illustrate marked enhancements in capturing complex land-cover changes. These promising improvements highlight an effective and robust way of treating land surface changes, especially land-cover changes in spatiotemporal image fusion.

The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and metabolism in response to nutrients, energy levels, and growth factors. It contains the atypical kinase mTOR and the RAPTOR subunit that binds to the Tor signalling sequence (TOS) motif of substrates and regulators. mTORC1 is activated by the small GTPase RHEB (Ras homologue enriched in brain) and inhibited by PRAS40. Here we present the 3.0 ångström cryo-electron microscopy structure of mTORC1 and the 3.4 ångström structure of activated RHEB–mTORC1. RHEB binds to mTOR distally from the kinase active site, yet causes a global conformational change that allosterically realigns active-site residues, accelerating catalysis. Cancer-associated hyperactivating mutations map to structural elements that maintain the inactive state, and we provide biochemical evidence that they mimic RHEB relieving auto-inhibition. We also present crystal structures of RAPTOR–TOS motif complexes that define the determinants of TOS recognition, of an mTOR FKBP12–rapamycin-binding (FRB) domain–substrate complex that establishes a second substrate-recruitment mechanism, and of a truncated mTOR–PRAS40 complex that reveals PRAS40 inhibits both substrate-recruitment sites. These findings help explain how mTORC1 selects its substrates, how its kinase activity is controlled, and how it is activated by cancer-associated mutations.

This study was designed to examine the immunoregulatory effects of alginate-derived oligosaccharides (ADOs) on farm-cultured Pacific white shrimp Penaeus vannameiand its resistance to Vibrio harveyi. Total hemocyte count, superoxide dismutase (SOD) activity, bacteriolytic activity, phagocytic rate (PR), the average number of beads ingested per cell (ABPC), and the protective efficacy for P. vannameichallenged with Vibrio harveyiwere determined. The study showed that the administration of ADOs at 1.0 g/kg of diet improved SOD activity, bacteriolytic activity, and PR by 25.2, 20.4, and 20.9%, respectively, 30 d after exposure. Total hemocyte count and ABPC showed no significant differences. The 96-h survival of the shrimp reached 46.7% and 90.0% when they were challenged with V. harveyiat concentrations of 1 × 107and 1 × 106cfu/shrimp, which was significantly higher than that in the control group. The results obtained indicate that ADOs can act as an immunoregulant for P. vannamei.

AbstractThis study was designed to examine the immunoregulatory effects of alginate-derived oligosaccharides (ADOs) on farm-cultured Pacific white shrimp Penaeus vannameiand its resistance to Vibrio harveyi. Total hemocyte count, superoxide dismutase (SOD) activity, bacteriolytic activity, phagocytic rate (PR), the average number of beads ingested per cell (ABPC), and the protective efficacy for P. vannameichallenged with Vibrio harveyiwere determined. The study showed that the administration of ADOs at 1.0 g/kg of diet improved SOD activity, bacteriolytic activity, and PR by 25.2, 20.4, and 20.9%, respectively, 30 d after exposure. Total hemocyte count and ABPC showed no significant differences. The 96-h survival of the shrimp reached 46.7% and 90.0% when they were challenged with V. harveyiat concentrations of 1 × 107and 1 × 106cfu/shrimp, which was significantly higher than that in the control group. The results obtained indicate that ADOs can act as an immunoregulant for P. vannamei.Received February 11, 2017; accepted July 29, 2017Published online September 18, 2017

AbstractInhibition of the binding of pathogenic adhesins to host glycans by suitable oligosaccharides forms the basis of antiadhesion therapies. Experiments were carried out to study the inhibition capability of oligosaccharides on the adhesion of four microorganisms (Escherichia coli, Vibrio cholerae, Campylobacter jejuni, and SalmonellaTyphimurium) to HT-29 cells. Results showed that, in the absence of oligosaccharides, all of the four pathogens efficiently adhered to the cells. Cell adhesion with different bacteria was inhibited by distinct oligosaccharides (e.g., the adhesion number relative to control of V. choleraecould be significantly decreased by pectin oligosaccharide and chitooligosaccharide to about 16.1% and 18.9%, respectively). Saturation studies showed that the extent of antiadhesive effect for most of the suitable carbohydrates was dependent on their concentration. The observations from the study suggest that various carbohydrates may have antiadhesive activity and may be useful in future therapeutic study.

Abstract A series of mannuronic acid (M-block) and guluronic acid (G-block) fractions (M1–M5 and G1–G5) with different molecular weights were obtained by lyase depolymerization of alginate and evaluated for in vitro antibacterial activity against 19 bacterial strains. The antibacterial data revealed that both types of fractions generally showed activity against certain tested bacteria, whereas M-block fractions showed broader spectra and more potent inhibition than G-block fractions. Among these fractions, M3 (molecular weight 4.235 kDa) exhibited the broadest spectrum of inhibition and high inhibitory activity against Escherichia coli (minimal inhibitory concentration, MIC = 0.312 µg mL-1), Salmonella paratyphi B (MIC = 0.225 µg mL-1), Staphylococcus aureus (MIC = 0.016 µg mL-1) and Bacillus subtilis (MIC = 0.325 µg mL-1).

In order to prepare the active agar oligosaccharide, agarase extracted from a strain of unidentified marine bacterium from the South China Sea coast was selected for the agar depolymerization. The optimum decomposing conditions were determined to be pH 7.0, 35 °C and halophilic properties 2%. Three main degraded products, AOS-1, AOS-2 and AOS-3, were separated by ethanol fractionation and anion exchange chromatography. The molecular mass was analyzed by MALDI-TOF-MS. The agar oligosaccharides exhibited antioxidative activities in scavenging hydroxyl free radical, scavenging superoxide anion radical and inhibiting lipid peroxidation. The fragment with the sulfate group showed stronger antioxidative activities than that without the sulfate group. Higher antioxidative activities were found when the molecular mass was increased. The results indicated that the antioxidative activities were closely related to the molecular mass of the agar oligosaccharides and the substitute groups binding the carbohydrate ring.

The influence of alginate-derived oligosaccharide (molecular weight 1445 Da) was tested on the maize seed germination at different concentrations. Assays of α-and β-amylase and protease activities showed the highest response at 0.75‰.Compared with the control, root growth on days 3 and 7 showed increases of 34% and18%, respectively; and shoot growth on day 7 an increase of 46%. In the case of protease activity, treatments with both 0.75‰ and 1.50‰ alginate-derived oligosaccharide gave higher activities than the control. These results indicate that the rate of seed germination was enhanced by increasing the activities of several enzymes beneficial for germination.

Hyaluronic acid (HA) hydrogels for injection were fabricated using 1, 4-butanediol diglycidyl ether (BDDE) as a cross-linker. We used hyaluronidase fermented by the marine bacteria Arthrobacter globiformis A152, to comprehensively investigate the effects of BDDE concentration on swelling degree, modification degree, morphology, HA content, anti-enzyme ability, and residual free cross-linker. The results showed that within a certain range, the measured modification degrees of the HA hydrogels and HA contents changed linearly with increased concentration of the cross-linker. However, the change in anti-enzyme ability was not linear, potentially reflecting the influence of the spatial network structure.