Fused Tricyclic Guanidine Alkaloids: Insights into Their Structure,Synthesis and Bioactivity

A marine natural product possesses a diverse and unique scaffold that contributes to a vast array of bioactivities. Tricyclic guanidine alkaloids are a type of scaffold found only in marine natural products. These rare skeletons exhibit a wide range of biological applications, but their synthetic approaches are still limited. Various stereochemical assignments of the compounds remain unresolved. Batzelladine and ptilocaulins are an area of high interest in research on tricyclic guanidine alkaloids. In addition, mirabilins and netamines are among the other tricyclic guanidine alkaloids that contain the ptilocaulin skeleton. Due to the different structural configurations of batzelladine and ptilocaulin, these two main skeletons are afforded attention in many reports. These two main skeletons exhibit different kinds of compounds by varying their ester chain and sidechain. The synthetic approaches to tricyclic guanidine alkaloids, especially the batzelladine and ptilocaulin skeletons, are discussed. Moreover, this review compiles the first and latest research on the synthesis of these compounds and their bioactivities, dating from the 1980s to 2022.     

Superoxide dismutase activity as a measure of hepatic oxidative stress in cattle following ethionine administration

The goal of this study was to assess if oxidative stress, as measured by alterations in the concentrations of antioxidant enzymes in the liver and erythrocytes of cattle, could be induced following dl-ethionine administration. Whole blood, serum and liver biopsy samples were collected 0, 4, 7 and 10 days after intra-peritoneal ethionine administration to five cows. The activities of the antioxidant enzymes copper zinc superoxide dismutase (Cu, Zn SOD) and catalase were assessed in the liver biopsies which were also examined histopathologically.Significant increases in hepatic Cu, Zn SOD concentrations (P < 0.01) were noted on days 7 and 10 post-treatment. Hepatic catalase activity decreased significantly (P < 0.01) on days 4, 7 and 10 post-treatment and erythrocyte Cu, Zn SOD activity was significantly increased on day 10. Serum biochemical analysis revealed a significant increase (P < 0.01) in non-esterified fatty acid concentrations on day 4 and significant decreases in total cholesterol and phospholipid levels on days 4 (P < 0.05), 7 (P < 0.01) and 10 (P < 0.01). In this model system, dl-ethionine administration was effective in inducing oxidative stress particularly reflected in the liver.     

Cottonseed, Protein and Oil Yields, and Oil Properties as Affected by Nitrogen and Phosphorus Fertilization and Growth Regulators

Two experiments were carried out at Giza Agric. Res. St., Agric. Res. Centre, Ministry of Agric, Egypt, during 1981 and 1982 seasons on cotton cultivar Giza 75 ( Gossypium barbadense L.) to investigate the influence of nitrogen fertilization rates (72, 144 or 216 kg N/ha), phosphorus levels (36 or 72 kg P₂O₅/ha) and three growth regulators (IAA, IBA or NAA), each was applied to cotton plants at 10 ppm and sprayed three times (70, 85 and 100 days after sowing), on cotton seed, protein and oil yields and oil properties. A randomized complete block design, with four replications treatment combinations was used.
The combined analysis of the results of the two seasons revealed that, cottonseed, oil and protein yields/ha increased by raising N- and P-levels and under the application of growth regulators. Seed index increased by raising the added-N and the applied growth regulants. No detectable effect of P-levels was observed. The seed oil percentage decreased, while the protein percentage increased by raising N-rate. Application of growth regulators and high P-level increased the seed oil percentage, while the seed protein percentage was not affected. The seed oil properties, i.e. acidity, saponification and iodine values, tended to decrease slightly by increasing N-rate and the application of growth substances, while a reverse trend was noticed by raising P-level. The mean values of oil specific gravity and refractive index did not show any definite response.     

Effects of Exogenous Putrescine Application on Hormone Content of Citrus aurantium L. Seedling under Salt Stress

A pot experiment was conducted in lath house to study the response of six month-old seedlings of sour orange （Citrus aurantium L.） irrigated with salinity water （1, 2 or 4 ds/m） for four month. The seedling was sprayed with putrescine at 0, 150 or 300 mg/L concentrations for three times with month interval, for investigation the effects of putrrescine spraying on hormonal changes in sour orange seedlings under salt stress. One month after the last putrescine application, the leaves of the vegetative shoots were picked for endogenous plant hormone determination. The results indicate that increasing level of irrigation water salinity to 4 ds/m significantly increased ABA, Put and SA; whereas, decreasing IAA and GA in leave. Spraying vegetative canopy with putreseine at 300 mg/L increased 1AA, SA, ABA and Put, while decreased GA. It can be concluded that the adverse effects of high salinity irrigated water on endogenous plant hormone can be ameliorated, to some extent, by exogenous application of Put at 150 mg/L or 300 mg/L concentration.     

Effects of Biochar and Phosphorus Fertilizers on Phosphorus Fractions,Wheat Yield and Microbial Biomass Carbon in Vertic Torrifluvents

The present work was carried out to investigate the effect of biochar and phosphorus (P) fertilizer application, on phosphorus fractions, soil microbial biomass carbon in a Vertisol during two seasons for wheat in field experiments. Phosphorus was added at 0%, 50%, 100% and 150% P of recommended P fertilizers, with or without biochar at a rate of 10 t h^?1 arranged in a randomized complete block design with three replicates. Results showed that the wheat grain yield increased by 56% to 69% in plots treated with the interaction of biochar and P mineral during the 2015 and 2016 growing seasons. Co-application of biochar with inorganic P produced up to 1.5 fold more microbial biomass C than either biochar or inorganic P applied alone. Sequential extraction of the biochar-treated with P revealed that HCl-P decreased, whereas others fractions increased with increasing P rate. The inorganic and organic P fractions were increased significantly when the biochar was combined with fertilizer P as compared to the biochar or inorganic P applied alone. The results of this study reveal that the co-application of biochar with inorganic P can be a promising strategy to improve soil productivity and soil quality in alkaline soil.     

Underground Vetch (Vicia sativa ssp. amphicarpa): A Potential Pasture and Forage Legume for Dry Areas in West Asia

Subterranean vetch [Vicia sativa ssp. amphicarpa (Dorth.) Aschers & Graebn.] is native to disturbed grasslands of the Mediterranean basin where heavy grazing, seasonal drought and erosion act as strong selection forces. It produces two pod types, above‐ground and 5 cm below the soil surface. Unlike subterranean clover (Trifolium subterranean L.), which buries its seeds after flowering above‐ground, subterranean vetch flowers and forms pods beneath the soil surface on underground stems. The aerial pods are produced after vegetative development ceases, while the underground pods are produced in ontogeny. The ability of this unusual vetch to survive in marginal areas with low rainfall (about 250 mm year^?1) and to produce nutritious herbage and pods is an important characteristic which helps address rehabilitation of degraded rangelands and increase feed production for small ruminants. Research at the International Center for Agricultural Research in the Dry Areas (ICARDA) during the 1988–93 growing seasons has assessed the herbage and seed productivity of underground vetch, its ability to grow in rotation with barley in marginal low‐rainfall areas, and its capacity to regenerate after heavy grazing. Drier conditions in 1989 favoured earlier underground flowering; the number of underground pods was higher than that of aerial pods. Grain yield of barley (var. Atlas) was around 2.0 t ha^?1 after underground vetch and only 1.2 t ha^?1 after barley. Grazing underground vetch had no effect on the productivity of the succeeding barley crop. The aerial and underground pods serve two distinct functions; aerial pods increase dissemination within suitable habitats, while underground pods increase the probability of plant survival under adverse conditions such as drought and heavy grazing. Underground vetch has two potential uses, namely the rehabilitation of marginal areas and production in rotation with barley.     

Bosonic stimulation in the formation of a bose-einstein condensate

The formation of a Bose-Einstein condensate of a dilute atomic gas has been studied in situ with a nondestructive, time-resolved imaging technique. Sodium atoms were evaporatively cooled close to the onset of Bose-Einstein condensation and then suddenly quenched to below the transition temperature. The subsequent equilibration and condensate formation showed a slow onset distinctly different from simple relaxation. This behavior provided evidence for the process of bosonic stimulation, or coherent matter-wave amplification, crucial to the concept of an atom laser.     

Lack of inhibitory effects of several fluoroquinolones on cytochrome P-450 3A activities at clinical dosage in dogs

Inhibitory effects of several fluoroquinolones (FQs) on liver CYP3A activities were examined by in vitro and in vivo tests in dogs. Midazolam (MDZ) hydroxylation rate was used to determine the CYP3A activities in liver microsomes. Enrofloxacin (EFX), ofloxacin (OFX) orbifloxacin (OBFX) and ciprofloxacin (CFX) were tested. None of the FQs changed Vmax, Km or intrinsic clearance (Vmax/Km) of MDZ. For in vivo test, we examined the effects of oral administration of EFX and OFX on the pharmacokinetics of quinidine (QN), a CYP3A substrate. EFX or OFX (10 mg/kg) was administered once a day for 3 days. QN (2 mg/kg) was intravenously injected at 2 h after the final dose of FQs administration. The same dose of QN was intravenously injected 3 weeks before the start of FQs administration for control. Neither EFX nor OFX changed the pharmacokinetic parameters of QN. These in vitro and in vivo consisted results suggest that these FQs lack the inhibitory effects on CYP3A activities in dogs. Hence, given these results, the risk of drug-drug interaction is unlikely to occur between FQs and CYP3A substrates in clinical situation in dogs.