Distribution of glycosphingolipids in the serum lipoproteins of normal human subjects and patients with hypo- and hyperlipidemias.

Five glycosphingolipids (GSL), glucosylceramide, lactosylceramide, trihexosylceramide, globoside, and hematoside (GM3) were studied in serum from normal human subjects and patients with dyslipoproteinemia and found to be exclusively associated with the various classes of serum lipoproteins. Based on a unit weight of lipoprotein protein, the total amount of GSL in serum normal subjects was twice as high in very low density lipoprotein (VLDL) (d less than 1.006 g/ml) and low density lipoprotein (LDL) (d 1.019-1.063 g/ml) as in high density lipoproteins HDL2 (d 1.063-1.125 g/ml) or HDL3 (d 1.125-1.21 g/ml). In abetalipoproteinemia the levels of serum GSL were slightly reduced when compared to normal serum and were all found in the only existing lipoprotein, HDL; this contained 2-3 moles of GSL/ mole of lipoprotein as compared to 0.5 GSL/mole in normal HDL. In hypobetalipoproteinemia and Tangier disease, the serum glycosphingolipids were 10 to 30% reduced in concentration compared to the 75% reduction in other lipids, and were again found to be associated only with the serum lipoproteins. The relative proportions of GSL did not vary substantially in the normo- and hypolipidemic subjects studied. Only in patients with homozygous familial hypercholesterolemia was there a significant (3-4-fold) elevation of all of the five GSL species and this elevation of all of the five GSL species and this elevation correlated well with that of the circulating cholesterol and LDL. On a molar basis the LDL of these patients contained the same amount of GSL as normal subjects (5 moles GSL/mole protein). It is concluded that: (1) glycosphingolipids are associated only with the major lipoprotein classes in both normal and dyslipoproteinemic serum; (2) the relative proportions of the five glycosphingolipids are not significantly affected by dyslipoproteinemia; (3) only in severe hypolipoproteinemia do the remaining serum lipoproteins carry a complement of glycosphingolipids greater than normal. Although our results establish that glycosphingolipids are intimately associated with serum lipoproteins, the mode of association or the structural and functional significance of such an association remains undetermined.     

Arabidopsis glucan synthase-like 10 functions in male gametogenesis

Callose or beta-1,3-glucan performs multiple functions during male and female gametophyte development. Callose is synthesized by 12 members of the glucan synthase-like (GSL) gene family in Arabidopsis thaliana. To elucidate the biological roles of Arabidopsis GSL family members during sexual development, we initiated a reverse genetic approach with T-DNA insertional mutagenesis lines. We screened T-DNA insertion lines for all members of the GSL gene family and detected homozygous mutant seedlings for all members except GSL10. Three independent alleles in GSL10, gsl10-1, gsl10-3 and gsl10-4 showed distorted segregation (1:1:0) of T-DNA inserts rather than Mendelian segregation (1:2:1). By genetic analysis through reciprocal cross, we determined that gsl10 pollen could not be transmitted to descendent. The mutant pollen of GSL10/gsl10 plants at tetrad and microspore stages were not different from that of wild type, suggesting that GSL10 is not essential for normal microspore growth. Analysis of GSL10/gsl10 hemizygous pollen during development revealed abnormal function in asymmetric microspore division. gsl10 mutant microspores failed to enter into mitosis. Unlike the previously described functions of GSL1, GSL2 and GSL5, GSL10 involves an independent process of pollen development at the mitotic division stage.     

The impact of growing-season length variability on carbon assimilation and evapotranspiration over 88 years in the eastern US deciduous forest

 Recent research suggests that increases in growing-season length (GSL) in mid-northern latitudes may be partially responsible for increased forest growth and carbon sequestration. We used the BIOME-BGC ecosystem model to investigate the impacts of including a dynamically regulated GSL on simulated carbon and water balance over a historical 88-year record (1900–1987) for 12 sites in the eastern USA deciduous broadleaf forest. For individual sites, the predicted GSL regularly varied by more than 15 days. When grouped into three climatic zones, GSL variability was still large and rapid. There is a recent trend in colder, northern sites toward a longer GSL, but not in moderate and warm climates. The results show that, for all sites, prediction of a long GSL versus using the mean GSL increased net ecosystem production (NEP), gross primary production (GPP), and evapotranspiration (ET); conversely a short GSL is predicted to decrease these parameters. On an absolute basis, differences in GPP between the dynamic and mean GSL simulations were larger than the differences in NEP. As a percentage difference, though, NEP was much more sensitive to changes in GSL than were either GPP or ET. On average, a 1-day change in GSL changed NEP by 1.6%, GPP by 0.5%, and ET by 0.2%. Predictions of NEP and GPP in cold climates were more sensitive to changes in GSL than were predictions in warm climates. ET was not similarly sensitive. First, our results strongly agree with field measurements showing a high correlation between NEP and dates of spring growth, and second they suggest that persistent increases in GSL may lead to long-term increases in carbon storage. Received: 26 May 1998 / Accepted: 6 July 1998     

Growth and ultrastructure of Streptomyces venezuelae during chloramphenicol production.

Streptomyces venezuelae (3022a) was grown in flask cultures and fermentors, using three media having differential effects on chloramphenicol production. Micromorphology, ultrastructure and chloramphenicol concentrations were studied during the growth cycle in each medium. Chloramphenicol production was greatest in the glycerol-serine-lactate (GSL) medium, less in the glycerol-nutrient broth-yeast extract (GNY) medium and very low in glucose-mineral salts (GA) medium. In GSL and GA, much growth was in the form of microcolonies, especially in flask cultures, while short hyphal fragments predominated in GNY. The major ultrastructural features were the high frequency of mesosomes in fragmenting hyphae in GNY, and electron-transparent zones which appeared during chloramphenicol synthesis in GSL. None of the structural abnormalities induced by chloramphenicol in sensitive organisms were observed in S. venezuelae despite high levels of the antibiotic in GSL medium.     

Glucosinolate survey of cultivated and feral mashua (Tropaeolum tuberosum Ruíz & PavÓn) in the Cuzco region of Peru

Glucosinolates (GSL) present in cultivated and feral accessions of mashua (Tropaeolum tuberosum í & Pavón) were identified and quantfied by High Performance Liquid Chromatography (HPLC) analysis. The nwin glucosinolates detected were aromatic: 4—Hydroxybenzyl GSL (OHB, Glucosinalbin), Benzyl GSL (B, Glucotropaeolin), and m—Methoxybenzyl GSL (MOB, Glucolimnathin). The total amount of GSL observed ranged from 0.27 to 50.74 micromols per gram (μMol/g) of dried tuber tissue. Most of the low-content GSL accessions are distributed within the cultivated population with a total GSL concentration lower than 5.00 μMol/g of dried tuber tissue. The highest total and specific GSL (OHB, B, and MOB) contents (more than 25.00 μMol/g of dried tuber tissue) were observed in the feral population with few exceptions. in addition, only six different GSL profiles were found: Only MOB; only B; OHB and B; OHB and MOB; B and MOB; and OHB, B and MOB.

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Contenido de Glucosinolatos en mashuas (Tropaeolum tuberosum Ruiz & Pavon) cultivadas y silvestres de la region del Cusco, Peru

Se identifico y cuantificó mediante “High Performance Liquid Chromatograph” los glucosinolatos (GSL) presentes en mashua cultivada (Tropaeolum tuberosum Ruíz & Pavón) y sus parientes silvestres. Los compuestos principales descubiertos fueron los siguentes glucosinolatos aromáticos: 4—Hydroxybenzyl GSL (OHB, Glucosinalbin), Benzyl GSL (B, Glucotropaeolin) y m—Methoxybenzyl GSL (MOB, Glucolimnathin). El contenido total de GSLfluctuó entre 0.27 a 50.74 μMol/g de tejido del tubérculo seco. La mayorIa de las accesiones con bajo contenido de GSL estuvieron distribuidos dentro de la población cultivada con una concentración total de GSL menor a 5.00 μMol/g de tejido del tubérculo seco, mientras que el mas alto contenido total (mds de 25.00 μMol/g de tejido del tubérculo seco) y la mas alta concentración de GSL individuales (OHB, B y MOB) se observó en Ia población silvestre con pocas excepciones. Además, seis fenotipos de GSL diferentesfueron determinados: Sólo MOB; sólo B; OHB y B; OHB y MO; B y MOB; y OHB, B y MOB.

     

Characterization of neutral glycosphingolipids from porcine erythrocyte membranes

1. Six neutral GSL fractions were purified from porcine erythrocyte membranes. 2. They were identified to be LacCer (14% of total neutral GSLs), 2-hydroxy acid-rich and -poor Gb3Cer (3 and 7%, respectively) and Gb4Cer (71%) by means of NMR spectrometry. 3. Monohexosylceramides (5%) were composed of GlcCer and GalCer with near amount. 4. All these GSL classes contained a high concentration (more than 20% of total acids in each class) of 2-hydroxy fatty acids. 5. GalCer and GlcCer contained considerable amounts of C16- and C18-acids, and of C18-phytosphingosine, whereas C24-acids and C18-sphingosine were predominant in the other GSLs. 6. A minor GSL fraction (less than 1% of total neutral GSLs) which migrated more slowly than Gb5Cer on a thin layer plate and composed of several GSL components contained L-fucose.     

Overexpression of glycogen synthase in mouse muscle results in less branched glycogen

Glycogen, a branched polymer of glucose, serves as an energy reserve in many organisms. The degree of branching likely reflects the balance between the activities of glycogen synthase and branching enzyme. Mice overexpressing constitutively active glycogen synthase in skeletal muscle (GSL30) have elevated muscle glycogen. To test whether excess glycogen synthase activity affected glycogen branching, we examined the glycogen from skeletal muscle of GSL30 mice. The absorption spectrum of muscle glycogen determined in the presence of iodine was shifted to higher wavelengths in the GSL30 animals, consistent with a decrease in the degree of branching. As judged by Western blotting, the levels of glycogenin and the branching enzyme were also elevated. Branching enzyme activity also increased approximately threefold. However, this compared with an increase in glycogen synthase of some 50-fold, so that the increase in branching enzyme in response to overexpression of glycogen synthase was insufficient to synthesize normally branched glycogen.     

中国植被生长期的时空变化

基于822个气象站点1951—2017年的日均温度数据,采用世界气象组织给定的植被生长期(GSL)定义,利用Slope、Mann-Kendall和Hurst指数分析中国各省(区)不同时期的GSL变化趋势及相应时期150、200、250、300和350 d的GSL等值线移动速度。结果表明: 研究期间中国北方地区GSL变化显著。GSL增长速度表现为北方快于南方、高海拔快于低海拔。中国大部分地区未来GSL变化趋势与当前的变化趋势相同。北方绝大部分省(区)GSL增长速度在0.1~0.2 d·a^-1,西藏的增速最快,为0.44 d·a^-1。1981—2000年是中国各省(区)GSL变化最显著的时段。除新疆GSL延长是生长期终日(GSE)主导外,其他各省(区)GSL延长总体是生长期始日(GSS)占主导。在高纬度和高海拔省(区),GSL变化对年均温度的变化更敏感。年均温越高的省(区)GSL也普遍越长。1951年以来,中国150、200、250、300和350 d的GSL等值线出现了明显移动,东北地区200 d等值线的移动速度最快,其平均北移速度为6.11 km·a^-1。中国GSL等值线总体移动规律为:等值线数值越大,北移速度越慢。其中,350 d等值线在部分区段甚至出现了南移的情况。中国GSL延长将导致农作物种植边界北移,自然植被生长期延长。该变化对中国农作物的品质、产量和生态系统碳固定的影响还有待深入研究。     

人参茎叶皂甙对高胆固醇饮食大鼠再灌注性心律失常和脂质过氧化的影响(英文)

研究人参茎叶皂甙(GSL)对高胆固醇饮食大鼠心肌再灌注性心律失常(RPA_r)和脂质过氧化的影响。方法:将胆固醇乳剂用灌胃法饲养大鼠14d,建立高脂血症模型,各组大鼠进行心肌缺血再灌注实验,观察高脂血症和GSL对大鼠心肌缺血再灌注2h后血丙二醇(MDA),超氧化物歧化酶(SOD)和一氧化氮(NO)水平的影响和对再灌注性心律失常发生率的影响。结果显示:(1)用胆固醇乳剂饲养大鼠14d,成功建立高脂血症模型。同时给予GSL14d有明显降脂作用。(2)高脂血症状态下,心肌缺血再灌注2h后,血MDA升高(p<0.01),SOD降低(p<0.01)和NO(p<0.05)降低,再灌注10min内RPAr的发生率增高。(3)GSL组再灌注后2h的血MDA降低,而SOD和NO水平显著升高;使RPAr发生率大为降低,无VF发生。实验显示高脂血症加重心肌缺血再灌注损伤和提高RPAr发生率及动物死亡率,GSL可减少高脂饮食大鼠脂质过氧化和诱导体内NO生成而减轻缺血再灌注心肌损伤,降低缺血再灌注性心律失常发生率。     

A unified view of the DNA-damage checkpoint

Recent investigation of the DNA-damage checkpoint in several organisms has highlighted the conservation of this pathway. The checkpoint's signal transduction pathway consists of four conserved classes of molecules: two large protein kinases having homology to phosphatidylinositol 3-kinases, three "sensor" proteins with homology to proliferating cell nuclear antigen, two serine/threonine (S/T) kinases, and two adaptors for the S/T kinases. This review compares the role of these four classes of checkpoint proteins in humans and model organisms.     

人参茎叶皂甙对高胆固醇饮食大鼠再灌注性心律失常和脂质过氧化的 …

To explore the effects of GSL on myocardial reperfusion arrhythmia and lipid superoxidation in high cholesterol diet rats. Hyperlipidemia model was set up with administered high cholesterol emulsion 15 ml/kg to rats orally for 14 days. In GSL group, rats were given GSL i.p. 75 mg/kg simultaneously when administered high cholesterol emulsion. The experiment of myocardial ischemia reperfusion was performed on all rats. The results showed: (1) After administration of high cholesterol emulsion to rats orally for 14 days, hyperlipidemia model was set up successfully, simultaneously treatment with GSL. It lowered serum lipid; (2) In hyperlipidemia state, serum MDA increased (p < 0.01, SOD and NO decreased markedly (p < 0.01 and p < 0.05 respectively) after 2 h of myocardial reperfusion; the rate of reperfusion arrhythmia (RPAr) increased within 10 min of reperfusion, four out of nine rats died of ventricular fibrillation (VF); and (3) GSL decreased MDA, increased SOD and NO after 2 h of myocardial reperfusion. All changes were significant (p < 0.01); the rate of RPAr decreased, no VF occurred and all rats survived. Hyperlipidemia aggravated myocardial ischemia reperfusion injury and increased the incidence of RPAr. The results suggested that GSL reduced myocardial ischemia reperfusion injury and RPAr in high cholesterol diet state through antiperoxidating and inducing the production of NO.     

An Arabidopsis Callose Synthase, GSL5, Is Required for Wound and Papillary Callose Formation

Arabidopsis was transformed with double-stranded RNA interference (dsRNAi) constructs designed to silence three putative callose synthase genes: GLUCAN SYNTHASE-LIKE5 (GSL5), GSL6, and GSL11. Both wound callose and papillary callose were absent in lines transformed with GSL5 dsRNAi and in a corresponding sequence-indexed GSL5 T-DNA insertion line but were unaffected in GSL6 and GSL11 dsRNAi lines. These data provide strong genetic evidence that the GSL genes of higher plants encode proteins that are essential for callose formation. Deposition of callosic plugs, or papillae, at sites of fungal penetration is a widely recognized early response of host plants to microbial attack and has been implicated in impeding entry of the fungus. Depletion of callose from papillae in gsl5 plants marginally enhanced the penetration of the grass powdery mildew fungus Blumeria graminis on the nonhost Arabidopsis. Paradoxically, the absence of callose in papillae or haustorial complexes correlated with the effective growth cessation of several normally virulent powdery mildew species and of Peronospora parasitica.     

A field study of nitrogen dynamics and spring barley growth as affected by the quality of incorporated residues from white clover and ryegrass

Biofumigation refers to the suppression of soil-borne pests and pathogens by biocidal compounds released by Brassicaceous green manure and rotation crops when glucosinolates (GSLs) in their tissues are hydrolysed. We investigated the effect of environment and ontogeny on the GSL production, and thus biofumigation potential, of eight entries from five Brassica species. The environments included autumn and spring sown field plots (FA and FS) and potted plants grown under ambient conditions (PAM) or in a temperature controlled glasshouse at 20 °C/12 °C (PTC). GSL concentration was measured in the root and shoot tissue at buds-raised, flowering and maturity. Of particular interest was the suitability of the pot-grown plants for screening large numbers of brassicas for GSL production. The type of GSLs present in the tissues and their relative proportions remained relatively constant across environments and at different growth stages, with the exception of an increase in indolyl GSLs in the FS environment suspected of being induced by insect attack. Total GSL concentration generally declined from buds-raised to flowering in all environments, and was lowest at maturity. The exceptions were B. campestris, which had higher GSL concentration at flowering than at buds-raised, and the PTC environment in which most species also showed an increase at flowering. Despite GSL types and their proportions remaining relatively constant, the total GSL concentration in the root and shoot tissue of all entries varied significantly with environment (3–10-fold) and was generally ranked FS>PAM>FA>PTC. Interactions between species and environments meant that the ranking of the Brassica entries for total shoot and root GSL concentration changed with environment. However within three entries from B. napus, the ranking was consistent across the environments. The added effect of environment on phenological development and biomass production further influenced GSL production (the product of GSL concentration and biomass) on a ground area basis. The results suggest that glasshouse environments can be used to determine the types and proportions of GSLs present, and to rank entries within, but not between species for the total concentration in the tissues. However the influence of the environment on both GSL concentration and biomass production suggests that an accurate estimate of GSL production on a ground area basis to assess biofumigation potential will require measurement in the target environment.     

Species: the concept, category and taxon

The term species by itself is vague because it refers to the species concept, the species category and the species taxon, all of which are distinct although related to one another. The species concept is not primarily a part of systematics, but has always been an integral part of basic biological theory, It is based on evolutionary theory and applies only to sexually reproducing organisms. The species concept and the phyletic lineage concept are quite distinct although they are related to one another. The important aspect of the species concept is lack of gene flow between different species, and hence the defining criterion of the species is genetic isolation. The species concept is often considered as non‐dimensional, both in time and space. Species possess three different major properties, namely genetic isolation, reproductive isolation and ecological isolation; these properties evolve at different times and under the effect of different causes during the speciation process. Speciation requires an external isolating barrier during the initial allopatric phase in which genetic isolation evolves and must reach 100% efficiency. The subsequent sympatric phase of speciation occurs after the disappearance of the external isolating barrier when members of the two newly evolved species can interact with one another and exert mutual selective demands on one another. Much of the reproductive and ecological isolation evolves during this secondary sympatric phase. The species category is a rank in the taxonomic hierarchy and serves as the basis on which the diversity of organisms is described; it is not the same as the species concept. The species category applied to all organisms, sexually and asexually reproducing. The species taxon is the practical application of the species category in systematics with the recognition of species taxa requiring many arbitrary decisions. No single set of rules exist by which the species category can be applied to all organisms. Recognition of species taxa in asexually reproducing organisms is based on amount of variation and gaps in the variation of phenotypic features associated with ecological attributes of these organisms as compared with similar attributes in sympatric species taxa of sexually reproducing organisms. Species taxa are multidimensional in that they exist over space–time and often have fuzzy borders. Because recognition of species taxa, including those in sexually reproducing organisms, depends on many arbitrary decisions especially when dealing with broad geographical and temporal ranges, species taxa cannot be used as the foundation for developing and testing theoretical concepts in evolutionary theory which can only be done with the non‐dimensional species concept.     

Age-specific life history tactics in organisms with determinate growth: Optimal models for non-optimal behavior?

Among organisms with determinate growth, optimization models predict that reproductive effort should increase as individuals approach old age, but the assumptions of these models may be inappropriate because the senescence that generates the necessary selective pressure may be not itself be optimal. Population genetics models were constructed to examine whether genes for age-specific changes in reproductive effort could invade a population in which senescence was maintained at equilibrium levels by a balance between mutation and selection. In asexually reproducing organisms, it was found that strategies of increasing reproductive effort could not normally invade the population. In sexually reproducing organisms, however, recombination was found to be important and genes for age-specific changes in effort could spread in the population under most circumstances.     

Dissection of genetic architecture for glucosinolate accumulations in leaves and seeds of Brassica napus by genome‐wide association study

Glucosinolates (GSLs), whose degradation products have been shown to be increasingly important for human health and plant defence, compose important secondary metabolites found in the order Brassicales. It is highly desired to enhance pest and disease resistance by increasing the leaf GSL content while keeping the content low in seeds of Brassica napus, one of the most important oil crops worldwide. Little is known about the regulation of GSL accumulation in the leaves. We quantified the levels of 9 different GSLs and 15 related traits in the leaves of 366 accessions and found that the seed and leaf GSL content were highly correlated (r = 0.79). A total of 78 loci were associated with GSL traits, and five common and eleven tissue‐specific associated loci were related to total leaf and seed GSL content. Thirty‐six candidate genes were inferred to be involved in GSL biosynthesis. The candidate gene BnaA03g40190D (BnaA3.MYB28) was validated by DNA polymorphisms and gene expression analysis. This gene was responsible for high leaf/low seed GSL content and could explain 30.62% of the total leaf GSL variation in the low seed GSL panel and was not fixed during double‐low rapeseed breeding. Our results provide new insights into the genetic basis of GSL variation in leaves and seeds and may facilitate the metabolic engineering of GSLs and the breeding of high leaf/low seed GSL content in B. napus.     

Isolation and structural elucidation of 4-(beta-D-glucopyranosyldisulfanyl)butyl glucosinolate from leaves of rocket salad (Eruca sativa L.) and its antioxidative activity

A structurally unique glucosinolate (GSL) was identified to be 4-(beta-D-glucopyranosyldisulfanyl)butyl GSL in rocket leaves. The positive-ion electrospray ionization mass spectrometry (ESI-MS) data indicated that the new GSL had a molecular weight of 521 (m/z 522, [M+H](+), as desulfo-GSL). The molecular formula of the substance was determined to be C(17)H(32)O(11)NS(3) (m/z 522.1143, [M+H](+)) based on its positive-ion high-resolution fast atom bombardment mass spectrometry (HR-FAB-MS) data. For the further confirmation, desulfated GSL of 4-(beta-D-glucopyranosyldisulfanyl)butyl GSL was prepared by commercial 1-thio-beta-D-glucose and dimeric 4-mercaptobutyl desulfo-GSL, which was also isolated from rocket leaves, and its chemical structure was then confirmed by MS data and nuclear magnetic resonance (NMR) spectroscopy. In addition, the antioxidative activity of 4-(beta-D-glucopyranosyldisulfanyl)butyl desulfo-GSL was measured by means of chemiluminescence (CL) for evaluating the functional properties. The antioxidative activity (2.089 unit/g) was relatively higher than that of dimeric 4-mercaptobutyl desulfo-GSL (1.227).     

Comprehensive characterization of complex glycosphingolipids in human pancreatic cancer tissues

Pancreatic ductal adenocarcinoma (PDAC) is one of the most common causes of cancer-related deaths worldwide, accounting for 90% of primary pancreatic tumors with an average 5-year survival rate of less than 10%. PDAC exhibits aggressive biology, which, together with late detection, results in most PDAC patients presenting with unresectable, locally advanced, or metastatic disease. In-depth lipid profiling and screening of potential biomarkers currently appear to be a promising approach for early detection of PDAC or other cancers. Here, we isolated and characterized complex glycosphingolipids (GSL) from normal and tumor pancreatic tissues of patients with PDAC using a combination of TLC, chemical staining, carbohydrate-recognized ligand-binding assay, and LC/ESI-MS². The major neutral GSL identified were GSL with the terminal blood groups A, B, H, Le^a, Le^b, Le^x, Le^y, P1, and PX2 determinants together with globo- (Gb₃ and Gb₄) and neolacto-series GSL (nLc₄ and nLc₆). We also revealed that the neutral GSL profiles and their relative amounts differ between normal and tumor tissues. Additionally, the normal and tumor pancreatic tissues differ in type 1/2 core chains. Sulfatides and GM₃ gangliosides were the predominant acidic GSL along with the minor sialyl-nLc₄/nLc₆ and sialyl-Le^a/Le^x. The comprehensive analysis of GSL in human PDAC tissues extends the GSL coverage and provides an important platform for further studies of GSL alterations; therefore, it could contribute to the development of new biomarkers and therapeutic approaches.