Antioxidant effects of isorhamnetin 3,7-di-O-beta-D-glucopyranoside isolated from mustard leaf (Brassica juncea) in rats with streptozotocin-induced diabetes

To investigate the effects of isorhamnetin 3,7-di-O-beta-D-glucopyranoside (isorhamnetin diglucoside), a major flavonoid compound of mustard leaf, on oxidative stress due to diabetes mellitus, in vivo and in vitro studies were carried out. Oral administration of isorhamnetin diglucoside (10 or 20 mg/kg of body weight/day for 10 days) to rats with streptozotocin-induced diabetes significantly reduced serum levels of glucose and 5-(hydroxymethyl)furfural (5-HMF), which is glycosylated with hemoglobin and is an indicator of oxidative stress. After intraperitoneal administration, isorhamnetin diglucoside did not show these activities. In addition, after oral administration, the thiobarbituric acid-reactive substance levels of serum, and liver and kidney mitochondria declined significantly compared with the control group in a dose-dependent manner, whereas after intraperitoneal administration these levels fell only slightly. On the basis of the oral and intraperitoneal results, it was hypothesized that isorhamnetin diglucoside was converted to its metabolite in vivo, and its conversion to its aglycone, isorhamnetin, by beta-glucosidase was confirmed; isorhamnetin acted as an antioxidant. Moreover, it was observed that isorhamnetin diglucoside had no effect on the 1,1-diphenyl-2-picrylhydrazyl radical, whereas isorhamnetin showed a potent antioxidant effect in vitro. In addition, intraperitoneal administration of isorhamnetin reduced serum glucose and 5-HMF levels. Furthermore, lipid peroxidation in blood, liver, and kidney associated with diabetes mellitus declined after the administration of isorhamnetin. These results suggest that isorhamnetin diglucoside is metabolized in vivo by intestinal bacteria to isorhamnetin and that isorhamnetin plays an important role as an antioxidant.     

Pelagic fishing at 42,000 years before the present and the maritime skills of modern humans

By 50,000 years ago, it is clear that modern humans were capable of long-distance sea travel as they colonized Australia. However, evidence for advanced maritime skills, and for fishing in particular, is rare before the terminal Pleistocene/early Holocene. Here we report remains of a variety of pelagic and other fish species dating to 42,000 years before the present from Jerimalai shelter in East Timor, as well as the earliest definite evidence for fishhook manufacture in the world. Capturing pelagic fish such as tuna requires high levels of planning and complex maritime technology. The evidence implies that the inhabitants were fishing in the deep sea.     

刺五加反季生产技术

刺五加属中草药、菜两用植物,具有很好的药用价值和广阔的市场前景。但由于近年滥砍乱伐和肓目开采．使有限的野生资源遭到严重破坏。尽快恢复野生资源,建立苗木繁育基地进行人工栽培势在必行。通过介绍刺五加反季生产技术．为农民栽培刺五加提供技术支持。     

Comment on "A centrosome-independent role for gamma-TuRC proteins in the spindle assembly checkpoint"

Müller et al. (Reports, 27 October 2006, p. 654) proposed a role for microtubule nucleation in mitotic checkpoint signaling. However, their observations of spindle defects and mitotic delay after depletion of gamma-tubulin ring complex (gamma-TuRC) components are fully consistent with activation of the established pathway of checkpoint signaling in response to incomplete or unstable interactions between kinetochores of mitotic chromosomes and spindle microtubules.     

试析省属农业高校的经费困难与对策

分析了省属农业高校经费困难的现状与原因，提出了克服困难的对策。     

Angiotensin-converting enzyme I inhibitory activity of phlorotannins from Ecklonia stolonifera

ABSTRACT:   As part of our study of the isolation of antihypertensive agents derived from natural marine products, the bioactivity of 10 edible Korean seaweeds were screened by angiotensin converting enzyme (ACE) inhibitory and peroxynitrite assays. Among the crude extracts of selected seaweeds, including five Phaeophyta ( Ecklonia stolonifera , E. cava , Pelvetia siliquosa , Hizikia fusiforme , and Undaria pinnatifida ), four Rhodophyta ( Gigartina tenella , Gelidium amansii , Chondria crassicaulis , and Porphyra tenera ) and one Chlorophyta ( Capsosiphon fulvescens ), the ethanol extracts of E. stolonifera , E. cava , P. siliquosa , U. pinnatifida , and G. tenella exhibited significant inhibitory properties against ACE at more than 50% inhibition at a concentration of 163.93 µg/mL. Phloroglucinol 1 , eckstolonol 2 , eckol 3 , phlorofucofuroeckol A 4 , and dieckol 5 had been isolated previously, and triphlorethol-A 6 and fucosterol 7 were isolated for the first time from E. stolonifera. Also, the ACE inhibitory and peroxynitrite scavenging properties of phlorotannins 1–6 were evaluated, along with fucosterol 7 obtained from E. stolonifera . Among profound peroxynitrite scavenging compounds 1–6 , phlorotannins 3 , 4 and 5 were also determined to manifest marked inhibitory activity against ACE, with 50% inhibition concentration (IC₅₀) values of 70.82 ± 0.25, 12.74 ± 0.15, and 34.25 ± 3.56 µM, respectively.     

Inhibitory activity of Ecklonia stolonifera and its isolated phlorotannins against Cu2+-induced low-density lipoprotein oxidation

Since the oxidation of low-density lipoprotein (LDL) is one of the main causes of atherosclerosis, Cu²⁺-induced LDL oxidation and conjugated diene formation is currently being explored for the development of pharmaceutical drugs or functional foods for the treatment of atherosclerosis. The present work investigated the inhibitory effects on in vitro Cu²⁺-induced human LDL oxidation and conjugated diene formation of the methanol (MeOH) extract of the edible brown alga (Ecklonia stolonifera) and its different solvent-soluble fractions, as well as the phlorotannins isolated from them. The most active ethyl acetate fraction was selected for chromatographic separation to isolate six phlorotannins: phloroglucinol (1), dioxinodehydroeckol (2), eckol (3), phlorofucofuroeckol A (4), dieckol (5), and 7-phloroeckol (6). Compounds 3?C6 showed potent inhibitory activity against Cu²⁺-induced LDL oxidation as compared with probucol, a well-known clinical therapeutic agent for hypercholesterolemia. Moreover, when compound 5 (at levels of 9 and 4.5???M) was used in combination with probucol (4.5???M), they additively inhibited Cu²⁺-induced LDL oxidation. In addition, 3?C5 significantly prolonged the lag time of conjugated diene formation at 10???M. These results suggest that the potent antiatherosclerotic effects of E. stolonifera and its isolated phlorotannins may be partly attributed to the inhibition of Cu²⁺-induced LDL oxidation and conjugated diene formation.     

Effect of dietary n-3 series fatty acids on sperm production in the freshwater crayfish, Astacus leptodactylus (Eschscholtz) (Astacidae)

The objective of the present work was to evaluate the effects of three different rates of long chain n-3 polyunsaturated fatty acid (LC n-3 PUFA) on the sperm number of Astacus leptodactylus. The experiment was carried out with the four following treatments: control group (not supplemented LC n-3 PUFA), D1 (1 %), D2 (2 %) and D3 (3 %). The sperm number of A. leptodactylus was counted; the reproductive system was weighted; and the macroscopical analysis of the testes and vasa deferentia (DVD) were conducted. In addition, gonado-somatic index (GI) and testes index (TI) were also calculated. The results showed that there was a significant difference between the crayfish fed LC n-3 PUFA supplemented diets (D1, D2, D3) and control in mean sperm number (P < 0.05). The highest sperm number was found for the crayfish fed D3 (6.27 ± 0.14 × 10⁸ sperm/distal vas deferens section). The results also showed that the reproductive system of the crayfish fed D3 and D2 was significantly heavier than that of the crayfish fed the control and D1 (P < 0.05). On the other hand, there was not a significant difference in the testes weight and vasa deferentia weight between the crayfish fed the control and D1, and between the crayfish fed D2 and D3 (P < 0.05). GI of the crayfish fed D3 and D2 was significantly higher than that of the crayfish fed control and D1 (P > 0.05), but there was not a significant difference in the TI of the crayfish fed control, D1, D2 and D3 (P > 0.05). In conclusion, diets containing different levels of LC n-3 PUFA significantly increase the sperm number of A. leptodactylus, and they are crucial for the production of higher number of sperm in this species.     

Effects of slaughter methods on physical,biochemical and microbiological quality of rainbow trout <Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis> and mirror carp <Emphasis Type="Italic">Cyprinus carpio</Emphasis> filleted in pre-, in- or post-rigor periods

Rainbow trout Oncorhynchus mykiss and mirror carp Cyprinus carpio were slaughtered by either percussion or asphyxiation. For determination of the physical (texture value) and biochemical quality attributes [pH, lactic acid, total volatile basic nitrogen (TVB-N), and malondialdehyde (MDA) values] of trout and carp, the fish were filleted immediately (within 2 h), 12 h after harvest (pre-rigor), 24 and 36 h after harvest (in-rigor), and finally 48 and 60 h after harvest (post-rigor). For microbiological quality attribute (mesophilic and psychrophilic bacteria count) analyses, the fish were filleted immediately (within 2 h) after harvest (pre-rigor), 24 h after harvest (in-rigor) and 48 and 72 h after harvest (post-rigor). By percussion slaughtering followed by pre-rigor filleting, it was possible to process rainbow trout and mirror carp without inflicting excessive handling stress. Percussion slaughter delayed onset of rigor and the percussion-slaughtered fish exhibited a long pre-rigor period (≈24 h), giving plenty time for pre-rigor processing. Percussion slaughtering and pre-rigor filleting of fish was considered to be superior to the traditional asphyxiation slaughtering with respect to texture, TVB-N and MDA attributes.