A Comparative Study on Selectivity of α-Conotoxins GI and ImI Using Their Synthetic Analogues and Derivatives

Comparative structure-function studies have been carried out for -conotoxin GI acting on nicotinic acetylcholine receptors (AChR) from mammalian muscles and from the electric organ of the Torpedo californica ray and for -conotoxin ImI, which targets the neuronal a7 AChR. A series of analogs has been prepared for this purpose: chemically modified derivatives, including a covalently linked dimer of GI, as well as analogs wherein one or several amino acid residues have been changed using solid-phase peptide synthesis. The activity of all compounds was assessed in competition with radioiodinated and/or tritiated -conotoxin GI for binding to the membrane-bound AChR of Torpedo californica. Binding of radioiodinated -conotoxin GI dimer was also monitored directly, revealing the largest, as compared to all other analogues, difference in the affinity between the two binding sites in the receptor (K_D 11 and 1200 nM). Comparison of binding data with the results of CD measurements point to important role of the spatial organization of the -conotoxin second loop in manifestation of their muscle or neuronal specificity.     

Dynamics of a Producer–Grazer Model Incorporating the Effects of Excess Food Nutrient Content on Grazer’s Growth

Modeling under the framework of ecological stoichiometric allows the investigation of the effects of food quality on food web population dynamics. Recent discoveries in ecological stoichiometry suggest that grazer dynamics are affected by insufficient food nutrient content (low phosphorus (P)/carbon (C) ratio) as well as excess food nutrient content (high P:C). This phenomenon is known as the “stoichiometric knife edge.” While previous models have captured this phenomenon, they do not explicitly track P in the producer or in the media that supports the producer, which brings questions to the validity of their predictions. Here, we extend a Lotka–Volterra-type stoichiometric model by mechanistically deriving and tracking P in the producer and free P in the environment in order to investigate the growth response of Daphnia to algae of varying P:C ratios. Bifurcation analysis and numerical simulations of the full model, that explicitly tracks phosphorus, lead to quantitative different predictions than previous models that neglect to track free nutrients. The full model shows that the fate of the grazer population can be very sensitive to excess nutrient concentrations. Dynamical free nutrient pool seems to induce extreme grazer population density changes when total nutrient is in an intermediate range.     

Comparative Study on Interaction of DNaseⅠ with Pollen Actin and Rabbit Muscle Actin

Actin purified from maize pollen grains like actin from other sources could considerably inhibit the activity of DNase Ⅰ . A linear relationship existed between inhibition and the concentration of actin. However, DNase Ⅰ was less inhibited by pollen actin than by rabbit muscle actin under the same conditions. The values of Kapp of inhibition were 1.25 μg/mL for pollen actin and 0.75 μg/mL for rabbit muscle actin. DNase Ⅰdepolymerized both pollen and rabbit muscle actin filaments. But the rate of depolymerization of pollen F-actin was higher than that of rabbit muscle F-actin under the same conditions.     

Effects of ω3 Polyunsaturated Fatty Acids on Growth and Tissue Fatty Acid Compositions of Maternal Rats and Their Progeny

The effects of ω3 polyunsaturated fatty acids [PUFA; mainly eicosapentaenoic acid (20: 5, ω3) and docosahexaenoic acid (22:6, ω3)] on the growth, tissue weights and fatty acid compositions of tissue total lipids in female rats and their progeny were investigated. Female rats of the Wistar strain, weighing 77~94g, were fed a 25% casein diet containing 5% of either corn oil (control), sardine oil or PUFA ethyl ester for 8 ~ 9 weeks prior to mating, and during gestation and lactation, and then for a further 2 weeks. The progeny were weaned to the maternal diet and then the latter was administered for a further 2 weeks. Dietary changes in the body weights of the dams were not generally seen, but the body weights at birth and growth of the offspring from the females supplied with the PUFA diet were inferior compared to those of the other groups. The fertility did not differ among the dietary groups. The weights of several tissues in the dams and the progeny increased in proportion to their body weights but not that of the progeny brain, which remained ' almost unchanged by the dietary fats. As to the fatty acid compositions of total lipids in the tissues, on the whole, decreased levels of ωβ fatty acids and increased percentages of ω3 fatty acids were found in the sardine and PUFA groups, the changes being greater in the PUFA group than in the sardine one. Such findings due to the feeding of PUFA were more remarkable in the progeny compared with in the dams. Eicosatrienoic acid (20: 3, ω9) was almost completely undetectable in the tissue total lipids of all the dietary groups.     

Effects of Nitrogen Source and Bacterial Elicitor on Isoflavone Accumulation in Root Cultures of Albizzia kalkora （Roxb.） Prain

Changes in cellular isoflavone （daidzein and genistein） contents were monitored in root cultures of Albizzia kalkora （Roxb.） Prain after feeding different ratios of NH4^＋/NO3^- and treatment with a biotic elicitor （three strains of Rhizobium sp.）. The NH4^＋/NO3^- ratio appears to be positively correlated with daidzein content in the roots and shows a negative correlation with genistein. Among the three different strains of Rhizobium used, the strain ATCC 15834 caused a 35% increase in daidzein production by infection. In the case of genistein, maximum production （94%） was obtained when cultures were treated on Day 6 by the strains ATCC 15834 and KCTC 1541. The biosynthetic pathway of the two isoflavones apparently reacts differently to the same culture conditions and the same strains of Rhizobium. Therefore, the present data suggest that the production of daidzein and genistein could be modulated by changing the NH4^＋/NO3^- ratio and the application of Rhizobium.     

Binding Modes of Phthalocyanines to Amyloid β Peptide and Their Effects on Amyloid Fibril Formation

The inherent tendency of proteins to convert from their native states into amyloid aggregates is associated with a range of human disorders, including Alzheimer’s and Parkinson’s diseases. In that sense, the use of small molecules as probes for the structural and toxic mechanism related to amyloid aggregation has become an active area of research. Compared with other compounds, the structural and molecular basis behind the inhibitory interaction of phthalocyanine tetrasulfonate (PcTS) with proteins such as αS and tau has been well established, contributing to a better understanding of the amyloid aggregation process in these proteins. We present here the structural characterization of the binding of PcTS and its Cu(II) and Zn(II)-loaded forms to the amyloid β-peptide (Aβ) and the impact of these interactions on the peptide amyloid fibril assembly. Elucidation of the PcTS binding modes to Aβ₄₀ revealed the involvement of specific aromatic and hydrophobic interactions in the formation of the Aβ₄₀-PcTS complex, ascribed to a binding mode in which the planarity and hydrophobicity of the aromatic ring system in the phthalocyanine act as main structural determinants for the interaction. Our results demonstrated that formation of the Aβ₄₀-PcTS complex does not interfere with the progression of the peptide toward the formation of amyloid fibrils. On the other hand, conjugation of Zn(II) but not Cu(II) at the center of the PcTS macrocyclic ring modified substantially the binding profile of this phthalocyanine to Aβ₄₀ and became crucial to reverse the effects of metal-free PcTS on the fibril assembly of the peptide. Overall, our results provide a firm basis to understand the structural rules directing phthalocyanine-protein interactions and their implications on the amyloid fibril assembly of the target proteins; in particular, our results contradict the hypothesis that PcTS might have similar mechanisms of action in slowing the formation of a variety of pathological aggregates.     

Synergetic Effects of Lactobacillus plantarum and β-Glucan on Digestive Enzyme Activity,Intestinal Morphology,Growth, Fatty Acid,and Glucose-Related Gene Expression of Genetically Improved Farmed Tilapia

Probiotics and Antimicrobial Proteins - The current study was conducted to evaluate the synergetic effects of heat-killed Lactobacillus plantarum (HK L-137) and β-glucan (BG) on digestive...     

Augmented Phytoextraction of Lead (Pb2+)-Polluted Soils: A Comparative Study of the Effectiveness of Plant Growth Regulators,EDTA, and Plant Growth–Promoting Rhizobacteria

Abstract

The role of gibberellic acid (GA3), indole-3-acetic acid (IAA), plant growth–promoting bacteria (Rhizobium and Azotobacter), and a synthetic chelator (EDTA; ethylenediaminetetraacetic acid) in lead (Pb) phytoextraction was evaluated using Parthenium hysterophorus (dicot, unpalatable noncrop) and Zea mays (monocot food/forage crop) plants at the flowering stage. Various plant parts were analyzed by atomic absorption/flame spectrophotometer for their Pb content. Both plant growth regulators and both growth-promoting bacteria significantly increased the plant growth in Pb-polluted soils, whereas EDTA significantly decreased growth and biomass of both plants. EDTA increased the Pb uptake (μg g^?1 dry biomass), but the total plant Pb accumulation was decreased. GA3 and IAA significantly increased both uptake and translocation, and the maximum total Pb in the entire plant of Parthenium was found with GA3 foliar spray, whereas in Z. mays the total Pb was maximum in the plant treated with GA3 in combination with EDTA, followed by the GA3 foliar spray treatment. Overall, the GA3 foliar application showed superior response compared with all other treatments. Further research is recommended to observe the role of endogenous GA3 levels in correlation with metal phytoextraction in different plants.     

A Comparative Study on Biosurfactant Activity of Crude Oil–Degrading Bacteria and Its Correlation to Total Petroleum Hydrocarbon Degradation

In this study, 11 bacteria isolated from Tapis crude oil–contaminated sites were identified by using biochemical tests and 16S rDNA gene sequencing. Their abilities to biodegrade Tapis crude oil was determined by gas chromatography before they were further screened for biosurfactant activity by employing qualitative (blood agar hemolysis, microplate assay, drop-collapse test), semiquantitative (emulsification formation), and quantitative (surface tension measurement) methods. Four isolates, namely, Acinetobacter baumanii UKMP-12T, Pseudomonas aeruginosa UKMP-14T, Rhodococcus sp. UKMP-5T, and Rhodococcus sp. UKMP-7T, exhibited high percentages in total petroleum hydrocarbon (TPH) degradation. A strong correlation between the emulsification index (E ₂₄) and surface tension measurement (r _s = +.866) as shown by Spearman rank correlation analysis suggested that these two methods were more reliable to predict biosurfactant activity. The TPH removal was also positively correlated to the ability of bacterial isolates to reduce the surface tension of growth medium, as revealed by Pearson correlation test (r_p = +.886). In conclusion, not all the biosurfactant detection protocols employed were effective. Nevertheless, the measurement of surface tension and E ₂₄ determination provided a rather rapid, easy, reproducible, and accurate result in identifying bacteria with biosurfactant-producing ability.     

A Comparative Study of the Diagnostic Value of Contrast-Enhanced Breast MR Imaging and Mammography on Patients with BI-RADS 3–5 Microcalcifications

Objective

To retrospectively investigate the diagnostic value of breast MRI in patients with BI-RADS 3–5 microcalcifications in mammography.

Methods

Eighty-four patients with BI-RADS 3–5 microcalcifications on mammography underwent breast MR exams before surgical biopsy with a hookwire position under mammographic guidance. Two radiologists reviewed each lesion with BI-RADS by consensus. The diagnostic value of mammography and MRI was compared.

Results

Histopathological examination revealed 49 benign lesions and 42 malignant lesions. In the assessments of mammography, 21 lesions (23.1%) were assigned to category 3, 51 lesions (56.0%) to category 4, and 19 lesions (20.9%) to category 5. The area under the receiver operating characteristic(ROC) curve for mammography and MR assessment was 0.844, and 0.945, respectively (p<0.05). In cases of category 3 microcalcifications, the specificity of mammography and MR was 100%, and 95.2% (p = 1.000), respectively. In cases of category 4 microcalcifications, the specificity, PPV and accuracy of mammography was 0%, 45.1% and 45.1%; whereas those for MR was 82.1% (p<0.05), 80.8% (P = 0.003) and 86.3% (p<0.05). All microcalcifications of category 5 were correctly diagnosed by mammography and MR.

Conclusions

Breast MRI has the potential to significantly improve the diagnosis of category 4 microcalcifications on mammography. Among mammographic category 4 microcalcifications, about 82% of benign lesions can be degraded to BI-RADS 1∼3 by MRI. However for microcalcifications of category 3 and 5, MR exams do not show significant improvement over mammography.     

Inhibitory Effects of Cycasin on Germination,Growth and α-Amylase Biosynthesis in Rice Plants

Cycasin, the toxic glycoside of cycad plants, interfered with seed germination and seedling growth of Gramineae, Crucifereae and Leguminosae. The shoots and roots of seedlings showed wilting, chlorosis and necrosis. Rice plants were most sensitive and soybean plants rather tolerant.

Respiration and α-amylase activity were markedly low in the rice seedlings treated with cycasin. Both cycasin and its aglycone, methylazoxymethanol, did not inhibit the activity of α-amylase, but did suppress the formation of α-amylase in rice endosperms. Exogenous gibberellin considerably reversed the inhibition of germination and growth, and the suppression of α-amylase formation caused by these toxins.     

Comparative Effects of β-Propiolactone on Mice, Mouse-derived Cell Cultures, and Venezuelan Equine Encephalomyelitis Virus

Studies were made comparing the toxicity of β-propiolactone (BPL) for mammalian (mouse) cells in vitro and for mice and for Venezuelan equine encephalomyelitis (VEE) virus which is highly cytopathogenic for each. The mammalian cells grown in tissue culture were found to be adversely affected by BPL in concentrations ranging from 0.001 to 0.1 mg/ml of supernatant fluid. The difference in response was influenced by the menstruum in which the BPL was suspended and the difference in cell types tested. Tenfold less BPL appeared to be required to destroy the cells when it was suspended in a balanced salt solution than when it was suspended in protein-containing solutions such as beef heart infusion broth or medium 199 plus 20% horse serum. Secondary embryonic mouse lung cells seemed slightly more adversely affected by BPL than the established embryonic lung or L cells. BPL given to mice by intranasal instillation and by intracerebral injection was lethal to half of the animals within 2 days at doses of 0.31 and 0.39 mg, respectively. Higher concentrations of BPL were required to rapidly inactivate the virus in vitro than were required to kill mice or to cause a toxic effect on cells in culture. It required 10 mg/ml of BPL to completely inactivate a high-titered VEE virus preparation in 5 min and 1 mg/ml to inactivate most, but not all, of the virus in 15 min. A concentration of 0.1 mg/ml of BPL had only a slight effect on the virus after a period as long as 60 min. Evidence is presented indicating that simultaneous inactivation of all of the properties of the VEE virus particles by BPL aerosols did not occur at the same time but that, after treatment, the virus possessed a limited ability to immunize mice despite a loss in infectivity.     

Fine Root Growth and Vertical Distribution in Response to Elevated CO<Subscript>2</Subscript>, Warming and Drought in a Mixed Heathland–Grassland

Belowground plant responses have received much less attention in climate change experiments than aboveground plant responses, thus hampering a holistic understanding of climate change effects on plants and ecosystems. In addition, responses of plant roots to climate change have mostly been studied in single-factor experiments. In a Danish heathland ecosystem, we investigated both individual and combined effects of elevated CO₂, warming and drought on fine root length, net production and standing biomass by the use of minirhizotrons, ingrowth cores and soil coring. Warming increased the net root production from ingrowth cores, but decreased fine root number and length in minirhizotrons, whereas there were no significant main effects of drought. Across all treatments and soil depths, CO₂ stimulated both the total fine root length (+44%) and the number of roots observed (+39%), with highest relative increase in root length in the deeper soil layers. Our results suggest that under future climate, plants may allocate considerable resources into roots compared to aboveground biomass. Increased carbon (C) allocation to roots may have a great impact on the overall ecosystem C balance and must be considered in modelling of future ecosystem responses to climate change. To provide models with necessary validation data, more studies are needed to investigate if higher C allocation to roots will lead to long-term C storage in more recalcitrant soil C pools or if this potential increase in soil carbon storage may be offset by increased priming activity and turnover rates for soil organic matter.     

Effect of Dietary Supplementation With α-Galactosidase Preparation and Stachyose on Growth Performance,Nutrient Digestibility and Intestinal Bacterial Populations of Piglets

Two experiments were conducted to investigate the effect of dietary supplementation with f -galactosidase preparation and stachyose on growth performance, nutrient digestibility and intestinal bacterial populations of piglets. In Experiment I 72 crossbred piglets were allotted to three treatments, i.e. 1) control (basal) diet, 2) f -Gal1 and 3) f -Gal5, the basal diet supplemented with 0.01% and 0.05% f -galactosidase preparation ( f -Gal), respectively. Average daily gain, average daily feed intake and feed conversion ratio were not influenced by f -Gal supplementation. In Experiment II 72 crossbred weanling piglets were randomly assigned to four treatments with a complete factorial design, i.e. 1) basal diet, 2) basal diet with 0.01% f -Gal supplementation, 3) basal diet with 1% stachyose supplementation and 4) basal diet with 1% stachyose and 0.01% f -Gal supplementation. Average daily gain and feed conversion ratio were influenced by f -Gal and stachyose supplementation. The ileal digestibility of stachyose, raffinose, gross energy and crude protein was improved significantly by f -Gal supplementation. The microbial populations in the intestine were modified by both f -Gal and stachyose supplementation. The data suggested that stachyose supplementation had an adverse effect on the growth performance of piglets and f -Gal supplementation could ameliorate it, especially in younger pigs.     

Synbiotic Effects of Aspergillus oryzae and β-Glucan on Growth and Oxidative and Immune Responses of Nile Tilapia,Oreochromis niloticus

Probiotics and Antimicrobial Proteins - Probiotic, prebiotic, and synbiotic application have got considerable attention in aquaculture as a functional feed additive. This trial was considered to...     

Effects of Moranoline, 4-O-α-D-Glucopyranosylmoranoline and Their N-Substituted Derivatives on Thermostability of Cyclodextrin Glycosyltransferase,Glucoamylase, and β-Amylase

In repeated glycosylmoranolines synthetic reaction at 55°C, cyclodextrin glycosyltransferase (CGT-ase, EC 2.4.1.19) from Bacillus stearothermophilus retained its activity for more than 600 days. A main stabilizing compound. was found to be 4-O-α-D-glucopyranosylmoranoline.

The thermostabilizing activities of moranoline, 4-O-α-D-glucopyranosylmoranoline, and their N-substituted derivatives were studied. Moranoline and its N-substituted derivatives stabilized glucoamylase. 4-O-α-D-Glucopyranosylmoranoline and its N-substituted derivatives stabilized CGT-ase and β-amylase.     

Pastoral Sedentarization and Its Effects on Children’s Diet,Health, and Growth Among Rendille of Northern Kenya

Throughout the arid regions of Africa formerly mobile pastoral populations are becoming sedentary. Although pastoral sedentarization is encouraged by international development agencies and national governments as solutions to food insecurity, poor health care, and problems of governance, it has not been demonstrated that abandoning the pastoral way of life, and particularly childrens access to milk and other livestock products, is beneficial to the health and well-being of pastoral populations. This paper reports the results of a 3-year study of one pastoral and four settled Rendille communities of northern Kenya based on data from 17 repeated bimonthly surveys of childhood dietary, growth, and morbidity patterns and household level economic strata. Bivariate analysis of 5,535 measurements from 488 children from birth to 9 years revealed that age-specific height and weight measurements for the pastoral community are uniformly heavier and taller than children from the sedentary villages. Multivariate analysis using Generalized Estimating Equations methodology showed that the amount of milk consumed was always a statistically significant determinant of child weight and height growth, regardless of drought or non-drought times and breastfeeding status. Other significant determinants of child growth include morbidity and poverty, both associated with sedentary communities. These results indicate that international development assistance should not neglect improvements in livestock production and support of pastoral movements in Africas arid lands.     

Endless Urban Growth? On the Mismatch of Population,Household and Urban Land Area Growth and Its Effects on the Urban Debate

In European cities, the rate of population growth has declined significantly, while the number of households has increased. This increase in the number of households is associated with an increase in space for housing. To date, the effects of both a declining population and decreasing household numbers remain unclear. In this paper, we analyse the relationship between population and household number development in 188 European cities from 1990–2000 and 2000–2006 to the growth of urban land area and per capita living space. Our results support a trend toward decreasing population with simultaneously increasing household number. However, we also found cites facing both a declining population and a decreasing household number. Nevertheless, the urban land area of these “double-declining” cities has continued to spread because the increasing per capita living space counteracts a reduction in land consumption. We conclude that neither a decline in population nor in household number “automatically” solve the global problem of land consumption.