Triazolide strigolactone mimics as potent selective germinators of parasitic plant Phelipanche ramosa     

Marcela Dvorakova  Adela Hylova  Petr Soudek  Sarka Petrova  Lukas Spichal  Tomas Vanek 《Pest management science》2019,75(7):2049-2056

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Microtubule stabilization reduces scarring and causes axon regeneration after spinal cord injury     

Hellal F  Hurtado A  Ruschel J  Flynn KC  Laskowski CJ  Umlauf M  Kapitein LC  Strikis D  Lemmon V  Bixby J  Hoogenraad CC  Bradke F 《Science (New York, N.Y.)》2011,331(6019):928-931

Hypertrophic scarring and poor intrinsic axon growth capacity constitute major obstacles for spinal cord repair. These processes are tightly regulated by microtubule dynamics. Here, moderate microtubule stabilization decreased scar formation after spinal cord injury in rodents through various cellular mechanisms, including dampening of transforming growth factor-β signaling. It prevented accumulation of chondroitin sulfate proteoglycans and rendered the lesion site permissive for axon regeneration of growth-competent sensory neurons. Microtubule stabilization also promoted growth of central nervous system axons of the Raphe-spinal tract and led to functional improvement. Thus, microtubule stabilization reduces fibrotic scarring and enhances the capacity of axons to grow.  相似文献   

A review of carbon isotopes of phytoliths: implications for phytolith-occluded carbon sources     

Yang  Shilei  Hao  Qian  Wang  Hailong  Van Zwieten  Lukas  Yu  Changxun  Liu  Taoze  Yang  Xiaomin  Zhang  Xiaodong  Song  Zhaoliang 《Journal of Soils and Sediments》2020,20(4):1811-1823

Journal of Soils and Sediments - Phytolith-occluded carbon (PhytOC) is mainly derived from the products of photosynthesis, which can be preserved in soils and sediments for hundreds-to-thousands of...  相似文献   

Dynamics of globular clusters     

Spitzer L 《Science (New York, N.Y.)》1984,225(4661):465-472

In their attempt to reach kinetic equilibrium, through gravitational encounters between separate stars, globular clusters are driven to destruction, with their cores collapsing and their outer regions expanding. The effects of core collapse, which apparently produces x-ray sources, are not yet fully understood, but white dwarfs and neutron stars, probably in binary systems, are thought to be involved, and possibly black holes as well.  相似文献   

The "soil" of Mars (viking 1)     

Shorthill RW  Moore HJ  Scott RF  Hutton RE  Liebes S  Spitzer CR 《Science (New York, N.Y.)》1976,194(4260):91-97

The location of the Viking 1 lander is most ideal for the study of soil properties because it has one footpad in soft material and one on hard material. As each soil sample was acquired, information on soil properties was obtained. Although analysis is still under way, early results on bulk density, particle size, angle of internal friction, cohesion, adhesion, and penetration resistance of the soil of Mars are presented.  相似文献   

Viking magnetic properties investigation: further results     

Hargraves RB  Collinson DW  Arvidson RE  Spitzer CR 《Science (New York, N.Y.)》1976,194(4271):1303-1309

The amounts of magnetic particles held on the reference test chart and backhoe magnets on lander 2 and lander 1 are comparable, indicating the presence of an estimated 3 to 7 percent by weight of relatively pure, strongly magnetic particles in the soil at the lander 2 sampling site. Preliminary spectrophotometric analysis of the material held on the backhoe magnets on lander 1 indicates that its reflectance characteristics are indistinguishable from material within a sampling trench with which it has been compared. The material on the RTC magnet shows a different spectrum, but it is suspected that the difference is the result of a reflectance contribution from the magnesium metal covering on the magnet. It is argued that the results indicate the presence, now or originally, of magnetite, which may be titaniferous.  相似文献   

Effects of accelerators on mobility of 14C-2,4-dichlorophenoxy butyric acid in plant cuticles depends on type and concentration of accelerator     

Shi T  Simanova E  Schönherr J  Schreiber L 《Journal of agricultural and food chemistry》2005,53(6):2207-2212

Effects of diethyl suberate (DESU), diethyl sebacate (DES), dibutyl suberate (DBSU), dibutyl sebacate (DBS), and tributyl phosphate (TBP) on diffusion of 14C-2,4-dichlorophenoxy butyric acid (2,4-DB) across cuticular membranes (CM) was studied. Astomatous CM were isolated enzymatically from Stephanotis floribunda Brongn. leaves, and diffusion was measured at 20 degrees C. The alkyl-substituted dicarboxylic acids constitute a homologous series with carbon numbers increasing from C12 to C18. Molecular weights increased only moderately from 230.0 (DESU) to 314.5 (DBS), while partition coefficients varied over orders of magnitude from 92 (DESU), to 1213 (DES), to 15,988 (DBSU), to 210,762 (DBS). All the above compounds turned out to be accelerators as they increased 2,4-DB mobility by up to 40-fold with accelerator concentrations in the CM ranging from only 9.2 to 105 g kg(-1). Efficacy (2,4-DB mobility in the presence/mobility in the absence of accelerators) increased with increasing concentrations of accelerators in CM or in reconstituted cuticular waxes. Plotting efficacy vs accelerator concentration in the CM resulted in straight lines, and their slopes increased in the order DBS (0.14), DBSU (0.31), DES (0.51), and DESU (0.85). Hence, DESU was the most powerful accelerator in this series as it increased 2,4-DB mobility in the CM about 6 times more than DBSU. Waxes constitute the major barrier in plant cuticles, and plots of efficacy vs accelerator concentration in Stephanotis wax were also linear, but compared to CM slopes were steeper by factors of 3.20 (DBS), 2.97 (DBSU), 2.70 (DES), and 1.62 (DESU). TBP was similarly effective as DESU, but plots of efficacy vs concentration were not linear, and curves approached a plateau at 60-80 g kg(-1). These data are discussed with regard to suitability of these accelerators for formulating systemic pesticides.  相似文献   

Maintenance of pregnancy in postpartum beef cows that have short-lived corpora lutea.     

R L Butcher  J E Reber  A W Lishman  K F Breuel  F N Schrick  J C Spitzer  E K Inskeep 《Journal of animal science》1992,70(12):3831-3837

The first two experiments examined the role of the uterus in low pregnancy rates of beef cows induced to ovulate by early weaning. At 20 to 25 d postpartum, one-half of the cows in Exp. 1 and 2 received a s.c. implant containing 6 mg of norgestomet (NOR) for 9 d (NOR-pretreated) and the remaining cows were untreated controls (CON). Lengths of first postpartum luteal phase after weaning of calves at d 7 after implant insertion were expected to be normal in NOR-pretreated and short in CON cows. In Exp. 1, cows of both groups received an implant containing 3 mg of NOR at d 4 after first estrus and a silastic implant with 15 or 25 mg of NOR at d 7 after first estrus. At 7 d after first estrus, two embryos were transferred into the uterus of each cow and pregnancy was diagnosed by ultrasonography at d 35. Blood samples were collected daily from onset of treatment to d 8 after estrus and then every other day to d 24. Only 4 of 22 cows were pregnant at d 35, concentrations of estradiol (E2) were elevated after luteolysis, and large follicles were present at d 35. In Exp. 2, all cows were injected with 100 mg of progesterone (P4) twice daily from d 4 to 35 after first estrus. Embryos were transferred, pregnancy was diagnosed, and blood samples were collected as in Exp. 1, except blood sampling was continued to d 34.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Phagocytic activity of neutrophilic granulocytes and antibody formation in swine with positive and negative reactions to halothane     

G Schlenker  M Westendorff  R Sedlag  L Jugert  E Spitzer 《Archiv fuer experimentelle veterinaermedizin》1986,40(2):272-276

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Relationship between fecal crude protein concentration and diet organic matter digestibility in cattle     

Lukas M  Südekum KH  Rave G  Friedel K  Susenbeth A 《Journal of animal science》2005,83(6):1332-1344

The positive relationship between fecal CP concentration and diet OM digestibility in cattle, which is based on increasing undigested microbial CP and decreasing fecal OM as OM digestibility increases, may be used as an indirect method for estimating diet OM digestibility from fecal CP concentration. Results of digestibility trials (445 individual observations) conducted at Hohenheim and Braunschweig, Germany, and at Gumpenstein, Austria, were used to study the relationship between CP concentration in feces (x, g/kg OM) and OM digestibility (y, %). The best fit was obtained with the curvilinear relationship y = ai -107.7e(-0.01515 x x), with a1 = 79.76 and a2 = 72.86 (R2 = 0.82; residual SD = 2.7; SE = 0.13), which takes into account the effects of location (i = 1 for Braunschweig and Hohenheim, and i = 2 for Gumpenstein). Dietary CP and crude fat concentration, and DMI had no effect on fecal CP content, whereas crude fiber content, proportion of concentrate in the diet, and forage type significantly affected CP concentration in feces; however, the magnitude of these effects was less than 2 percentage units, and the direction of the effect of proportion of concentrate in the diet was not uniform. The curvilinear relationship between fecal CP concentration (observed range, 100 to 300 g/kg of OM) and diet OM digestibility (observed range = 57 to 80%) may be used to estimate diet OM digestibility, particularly for field trials, as it requires no feed samples and does not physically restrict the animal.  相似文献