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151.
The marine sponge of the genus Geodia, Jaspis, Rhabdastrella, and Stelletta are characterized chemically by a variety of isomalabaricane triterpenes. This class of compounds drew spotlights in marine lead discovery due to their profound anti-proliferative properties. Further research on exploring its chemical diversity led to the identifications of two new isomalabaricane-type triterpenes rhabdastin H (1) and rhabdastin I (2). Their structures were unraveled using a series of spectroscopic approaches. These isolates were found to exhibit unique structural features with the only reported tetrahydrofuran functionality among all marine-derived isomalabaricanes. Both compounds 1 and 2 showed activities against K562 (IC50 11.7 and 9.8 μM) and Molt4 (IC50 16.5 and 11.0 μM) leukemic cells in MTT cell proliferative assay.  相似文献   
152.
Toxicity effects and field persistence of the insect growth regulators lufenuron, flufenoxuron and triflumuron were assessed in the laboratory using second and fourth larval instars of Spodoptera littoralis. Laboratory bioassays indicated that lufenuron was more effective on both 2nd and 4th larval instars, as well as killing both larval instars faster than flufenoxuron or triflumuron. Field-laboratory experiments were conducted to show direct and residual effects of the tested IGRs in terms of toxicity and stability. They indicated that all the tested insecticides were stable under field conditions and give high percentages of mortality. Overall, lufenuron was more efficient than the other tested insecticides. In addition, it gave a faster kill in some testing periods. Data presented in this work show greater efficiency of lufenuron in controlling S. littoralis than flufenoxuron or triflumuron. Using this insecticide for cotton leafworm control in cotton fields may give better results under field condition.  相似文献   
153.
Chemical investigation of the Mediterranean sponge Sarcotragus spinosulus led to the isolation of a new hydroxylated nonaprenylhydroquinone, along with two known metabolites, hepta- and octaprenylhydroquinones. The structure of the new metabolite was assigned by extensive 1D and 2D NMR analyses and MS studies. The antileukemic effect of the three compounds towards the chronic myelogenous leukemia (CML) cells line K562 was also evaluated.  相似文献   
154.
Purslane (Portulaca oleracea), grown under greenhouse conditions, was harvested at three growth stages and analyzed for total solids, total protein, ash, soluble carbohydrate, and fructose/fructane in whole plants, leaves, stems, and roots. Significant increases were observed in total solids and protein during plant maturation. Leaves had the highest amount of protein in the third growth stage (44.25g/100g dry matter). Roots showed a decline in protein level as the plant aged. Soluble carbohydrate was significantly higher in growth states 1 and 3. Significant variation among growth stages was found with regard to total phosphorous, calcium, potassium, iron, managanese, and copper. Total phosphorus (P) content in leaves was significantly higher than P found in stems and roots. Iron (Fe) content varied significantly among growth stages, and roots and leaves had the highest Fe content (121.47 and 33.21 mg, respectively). Significant accumulation of managanese (Mn) was found in different growth stages. Leaves and roots had significantly higher Mn content than stems.  相似文献   
155.
Gorgostane steroids are isolated from marine organisms and consist of 30 carbon atoms with a characteristic cyclopropane moiety. From the pioneering results to the end of 2021, isolation, biosynthesis, and structural elucidation using 13C-NMR will be used. Overall, 75 compounds are categorized into five major groups: gorgost-5-ene, 5,6-epoxygorgostane, 5,6-dihydroxygorgostane, 9,11-secogorgostane, and 23-demethylgorgostane, in addition to miscellaneous gorgostane. The structural diversity, selectivity for marine organisms, and biological effects of gorgostane steroids have generated considerable interest in the field of drug discovery research.  相似文献   
156.
Several natural products recovered from a marine-derived Aspergillus niger were tested for their inhibitory activity against SARS CoV-2 in vitro. Aurasperone A (3) was found to inhibit SARS CoV-2 efficiently (IC50 = 12.25 µM) with comparable activity with the positive control remdesivir (IC50 = 10.11 µM). Aurasperone A exerted minimal cytotoxicity on Vero E6 cells (CC50 = 32.36 mM, SI = 2641.5) and it was found to be much safer than remdesivir (CC50 = 415.22 µM, SI = 41.07). To putatively highlight its molecular target, aurasperone A was subjected to molecular docking against several key-viral protein targets followed by a series of molecular dynamics-based in silico experiments that suggested Mpro to be its primary viral protein target. More potent anti-SARS CoV-2 Mpro inhibitors can be developed according to our findings presented in the present investigation.  相似文献   
157.
Marine environment has been identified as a huge reservoir of novel biometabolites that are beneficial for medical treatments, as well as improving human health and well-being. Sponges have been highlighted as one of the most interesting phyla as new metabolites producers. Dactylospongia elegans Thiele (Thorectidae) is a wealth pool of various classes of sesquiterpenes, including hydroquinones, quinones, and tetronic acid derivatives. These metabolites possessed a wide array of potent bioactivities such as antitumor, cytotoxicity, antibacterial, and anti-inflammatory. In the current work, the reported metabolites from D. elegans have been reviewed, including their bioactivities, biosynthesis, and synthesis, as well as the structural-activity relationship studies. Reviewing the reported studies revealed that these metabolites could contribute to new drug discovery, however, further mechanistic and in vivo studies of these metabolites are needed.  相似文献   
158.

In the North Nile Delta of Egypt, the impacts of overplanting paddy rice on water delivery performance have not been discussed quantitatively. Further, the amount of water that could have been saved if farmers would follow the planned area is unknown. In this study, water delivery performance was assessed by comparison of actual paddy rice planting and the government’s planned conditions. For both conditions, performance indicators relating to adequacy, equity, and dependability were analyzed across six locations in conjunction with the branch canal water level in 2013 and 2014. Based on the difference between the actual water supply and planned water demand, the amount of water that could have been saved for downstream uses was calculated. The average adequacy for the investigation period was good at one location, fair at 2 locations, and poor at 3 locations in both years. Further, adequacy under both actual and planned conditions was poor in late July at all locations. The planned adequacy and dependability downstream and equity among locations improved compared to the actual condition in both years. Under the condition that paddy rice area is the upper limit planned by the government, about 12.3% and 9.6% of water could be potentially saved in each year. The difference between actual and planned water delivery performance is caused by the branch canal’s low water level. Control of overplanting paddy rice and coordination of water distribution among water user associations would improve stable water level in the canal and, eventually, water delivery performance.

  相似文献   
159.
Although the pineapple leaf fibers (PALF) are long known as domestic threading material in Malaysia, they are currently of little use despite being mechanically and environmentally sound. This study evaluated some selected properties of Josapine PALF and PALF-vinyl ester composites as well as the effects of simple abrasive combing and pretreatments on fiber and composite properties. Using PALF vascular bundles extracted from different parts of the leaves did not significantly affect PALF-vinyl ester composite mechanical properties. At low weight fraction and consolidating pressure, PALF fibers regardless of diameters and locations performed equally well in enhancing composite flexural properties under static loading. Finer bundles enhanced PALF-vinyl ester composite toughness indicated by tests at higher speeds. Abrasive combing produces cleaner and finer bundles suitable for reinforcing composites for applications not requiring high toughness.  相似文献   
160.
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