In-mouth amylase activity can reduce perception of saltiness in starch-thickened foods     

Ferry AL  Mitchell JR  Hort J  Hill SE  Taylor AJ  Lagarrigue S  Vallès-Pàmies B 《Journal of agricultural and food chemistry》2006,54(23):8869-8873

Sensory scores for saltiness and thickness obtained for savory liquids thickened with starches or the nonstarch hydrocolloid hydroxypropylmethyl cellulose (HPMC) were correlated with the panelists' amylase activity. Although higher enzyme activities were linked to lower thickness scores for systems thickened by starch, they were also associated with a decreased taste perception, particularly for starches retaining a granular structure after gelatinization (wheat and modified waxy maize). Microscopic evidence showed that the enzyme can disrupt such structures, and this is associated with a decreased mixing efficiency with water and consequently a reduced transport of tastant (sodium) to the saliva (aqueous) phase and to the taste buds. This explains the lower saltiness scores for subjects with higher amylase activity, even if they are associated with a lower perceived thickness.  相似文献   

Molecular phylogeny and evolution of morphology in the social amoebas   总被引：1，自引：0，他引：1  

Schaap P  Winckler T  Nelson M  Alvarez-Curto E  Elgie B  Hagiwara H  Cavender J  Milano-Curto A  Rozen DE  Dingermann T  Mutzel R  Baldauf SL 《Science (New York, N.Y.)》2006,314(5799):661-663

The social amoebas (Dictyostelia) display conditional multicellularity in a wide variety of forms. Despite widespread interest in Dictyostelium discoideum as a model system, almost no molecular data exist from the rest of the group. We constructed the first molecular phylogeny of the Dictyostelia with parallel small subunit ribosomal RNA and a-tubulin data sets, and we found that dictyostelid taxonomy requires complete revision. A mapping of characters onto the phylogeny shows that the dominant trend in dictyostelid evolution is increased size and cell type specialization of fruiting structures, with some complex morphologies evolving several times independently. Thus, the latter may be controlled by only a few genes, making their underlying mechanisms relatively easy to unravel.  相似文献   

Humanization of yeast to produce complex terminally sialylated glycoproteins     

Hamilton SR  Davidson RC  Sethuraman N  Nett JH  Jiang Y  Rios S  Bobrowicz P  Stadheim TA  Li H  Choi BK  Hopkins D  Wischnewski H  Roser J  Mitchell T  Strawbridge RR  Hoopes J  Wildt S  Gerngross TU 《Science (New York, N.Y.)》2006,313(5792):1441-1443

Yeast is a widely used recombinant protein expression system. We expanded its utility by engineering the yeast Pichia pastoris to secrete human glycoproteins with fully complex terminally sialylated N-glycans. After the knockout of four genes to eliminate yeast-specific glycosylation, we introduced 14 heterologous genes, allowing us to replicate the sequential steps of human glycosylation. The reported cell lines produce complex glycoproteins with greater than 90% terminal sialylation. Finally, to demonstrate the utility of these yeast strains, functional recombinant erythropoietin was produced.  相似文献   

Evaluating the spatial range of the effect of synchronized antiparasitic treatments on the abundance of sea lice Caligus rogercresseyi (Boxshall & Bravo, 2000) in Chile          下载免费PDF全文

Gabriel A Arriagada  Sandra L Marín 《Aquaculture Research》2018,49(2):816-831

Sea lice are the most important ectoparasites affecting farmed salmonids in marine water worldwide and pharmacological treatments are widely used to control their abundance. Synchronization of antiparasitic treatments among closely located salmon farms has been recently evaluated as a promising strategy for improving treatment performance. However, the optimum distance at which farms should synchronize their treatments is not clear. We used a repeated measures linear mixed effects model to evaluate the impact of two nationwide treatment synchronization procedures conducted in Chile in 2014 and 2015 on subsequent adult lice counts up to 13 weeks after the procedure. Each treatment synchronization procedure consisted of two 2‐week synchronization windows, in which farms were required to treat their fish. A period of 3 weeks elapsed between the two windows. Treatment synchronization was measured as the number of neighbouring farms that treated their fish within a certain geographical threshold, each of them weighted by its distance from the farm of interest. We tested four different thresholds: 5, 10, 20 and 30 km. The results indicate that the abundance of adult lice on farms that synchronized treatments with their neighbours within a distance of 5 km was lower than the abundance on non‐synchronized farms from weeks 4 to 11 after the procedure. Our findings suggest the treatment synchronization effect was distance dependent and greater when neighbouring farms up to 5 km joined the procedure.  相似文献   

Influence of pheromone emission on the attraction of California red scale males in citrus orchards     

Sandra Vacas  Jaime Primo  Vicente Navarro-Llopis 《国际虫害防治杂志》2017,63(1):10-17

Attraction of California red scale males, Aonidiella aurantii (Maskell), to different release rates of the sex pheromone compound 3-methyl-6-isopropenyl-9-decen-1-yl acetate was evaluated in field trials. This study was aimed to study pheromone emission-response correlations and the existence of an optimum release rate that maximizes trapping efficacy. Release profiles of the pheromone dispensers deployed were determined by gas chromatography to estimate the various emission rates tested. The results reveal that the mean number of A. aurantii males caught correlates with the daily pheromone release rates by means of a quadratic model. The obtained model indicates the existence of a relative maximum of the captures corresponding to an optimum release rate of ca. 300 μg/day. Higher emission rates (up to 1 g/day) resulted in lower captures. Implications for the mating disruption technique are discussed.  相似文献   

Genetic diversity and changes in phenolic contents and antiradical activity of <Emphasis Type="Italic">Vaccinium myrtillus</Emphasis> berries from its southernmost growing area in Italy     

Edgardo Giordani  Stefano Biricolti  Claudia Ancillotti  William Antonio Petrucci  Massimo Gori  Elisa Calistri  Serena Orlandini  Sandra Furlanetto  Massimo Del Bubba 《Genetic Resources and Crop Evolution》2018,65(4):1173-1186

In this study, we evaluated by the RAPD technique the genetic diversity of 42 individual Vaccinium myrtillus L. plant samples, collected from different locations of Tuscan Apennines (Italy), which represent the southernmost growing latitude of this plant. Total polyphenols, total anthocyanins and radical scavenging activity were also determined in two successive harvesting years on bilberry samples obtained from the same individuals characterized by molecular analysis. The RAPD analysis indicated a highly prevalent gamic propagation of bilberry in the investigated area, and, in accordance with genetic findings elsewhere reported for populations of Central and Northern Europe, suggested the presence, from North-to-South Europe, of a clonal-to-gamic genetic gradient of the propagation strategy. In the context of a quite homogeneous panorama of biochemical data, significant variations were occasionally evidenced by comparing closely-located individuals. We tentatively attributed such variations mainly to genetics, due to the very close location of biomes exhibiting different biochemical attributes. However, molecular clustering by RAPD did not show any relationship with biochemical diversity. Strong variations of climatic conditions were probable responsible of the remarkable variability of the investigated biochemical parameters in the two harvesting years.  相似文献   

The relative importance of soil properties and regional climate as drivers of productivity in southern Patagonia’s <Emphasis Type="Italic">Nothofagus antarctica</Emphasis> forests     

Héctor A. Bahamonde  Guillermo Martínez Pastur  María V. Lencinas  Rosina Soler  Yamina M. Rosas  Brenton Ladd  Sandra Duarte Guardia  Pablo L. Peri 《Annals of Forest Science》2018,75(2):45

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Untersuchungen zum notwendigen Maß bei der Anwendung von Pflanzenschutzmitteln in Winterweizen in den Jahren 2004 bis 2016     

Jürgen Schwarz  Bettina Klocke  Christina Wagner  Sandra Krengel 《Gesunde Pflanzen》2018,70(3):119-127

In order to provide recommendations for future cropping systems with regard to the necessary minimum of pesticide use, a long-term field trial at the field site in Dahnsdorf of the Julius Kühn-Institute was conducted in the years 2004 to 2016 to investigate possible reduction of pesticides, taking into account the general principles of integrated pest management (Strategies to reduce the use of plant protection products). Two winter wheats (WW1 and WW2) were part of the crop rotation with six components and different quality classes (A wheat (WW1) and E wheat (WW2)) and resistance levels to important wheat pathogens. In all years, herbicides and fungicides were needed to control weeds and fungal pathogens due to the excess of the control threshold. Insecticides were only necessary in two years. When considering the treatment frequency index (TFI), the mean overall TFI varied with 2.6 in WW1 and 3.5 in WW2, but was significantly lower compared to practice. There were also differences in the mean fungicide TFI of the two crop rotation elements with 1.1 in WW1 and 1.6 in WW2 due to their different resistance level to important fungal pathogens. The same is true with regard to the herbicide TFI with of 1.1 in WW1 and 1.3 in WW2. The treatments in the strategies 2, 3 and 4 mostly resulted in significantly higher yields compared to the non-chemical strategy 1, which can be attributed to the strong weed and fungal infestations in strategy 1 and the good efficacy of the used plant protection products. The tended differences between strategy 2 with a situation-related application rate and the 25 and 50% reduced application rates in strategies 3 and 4, respectively, were not significant. A reduced application rate showed no negative long-term effects on weed emergence even after 13 years, but increased emergence numbers in strategies with reduced herbicide use. The results show that plant protection products savings are possible without significantly reducing yields. However, this requires a high level of human resources for monitoring and scoring the consistent observance of the principles of integrated pest management, such as the consideration of good crop rotation, the cultivation of resistant cultivars and the optimally coordinated treatments after the control threshold has been exceeded.  相似文献   

Effects of drought on weed emergence and growth vary with the seed burial depth and presence of a cover crop          下载免费PDF全文

Stéphane Cordeau  Sandra Wayman  Carole Reibel  Florence Strbik  Bruno Chauvel  Jean‐Philippe Guillemin 《Weed Biology and Management》2018,18(1):12-25

In conservation agriculture, weed seed germination could decrease with the presence of a cover crop, surface weed seed location and temporal drought in summer just after seed shedding. This study simultaneously examined the effects of a cover crop, burial depth (seed location) and hydric stress on weed emergence and early growth. It was hypothesized that drought would reduce weed emergence and the initial growth of weed seeds and that this effect would be greater when the seeds were on the soil surface and in the presence of a cover crop. Four annual weed species were chosen that are frequently found (Anisantha sterilis, Vulpia myuros, Sonchus asper, Veronica persica) and not frequently found (Alopecurus myosuroides, Poa annua, Cyanus segetum, Capsella bursa‐pastoris) in fields that implement conservation agriculture. The unburied seeds had 26% lower emergence, on average, than the buried seeds (significant for six of the eight species), hydric stress reduced emergence by 20% (for seven of the eight species) and the presence of a cover crop reduced the level of emergence by 17% (for all species). The unburied seeds with hydric stress were emerging under the “most stressful” set of factors, with a 45% decrease in emergence, compared with the seeds emerging under the “least stressful” set of factors (buried seeds without hydric stress). All the weed growth measurements (height, dry matter content and number of leaves) decreased with the presence of a cover crop. The species that are found frequently in the fields that implement conservation agriculture, compared with the species that are not frequently found in conservation agriculture fields, had higher rates of germination and a higher tolerance of hydric stress when their seeds were unburied.  相似文献