Effectiveness of freezer storage in fulfilling the chilling requirement of fall-lifted ponderosa pine seedlings     

Steven K. Omi  Robin Rose  Thomas E. Sabin 《New Forests》1991,5(4):307-326

The degree to which freezer storage fulfilled the chilling requirement of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) seedlings of two sources was determined by monitoring their development after potting or planting. The seedlings were lifted in September, October, November, or March and subjected to storage before outplanting. The fulfillment of chilling was assessed by measuring days to budbreak, cumulative percentage of seedlings flushing, foliated shoot length, and rate of bud abortion. The effect of freezer storage depended on stage of seedling development at lifting, length of storage, and seed source. Storage did not totally replace winter conditions, especially for seedlings lifted in September and October. Those from a high-elevation seed source flushed sooner than those from a low-elevation source. Delayed budbreak after planting of early lifted seedlings from the high-elevation source disappeared in the second year, but those from the low-elevation source continued to show effects. Seedlings lifted and stored in November had patterns of budbreak that were similar to those of seedlings that had overwintered in beds.  相似文献   

Effects of soil water content and initial root volume on the nutrient status of 2+0 Douglas-fir seedlings     

Diane L. Haase  Robin Rose 《New Forests》1994,8(3):265-277

Two-year-old bareroot Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco.) seedlings were graded on the basis of four root-volume categories and transplanted to four moisture-stress treatments (6, 12, 18, and 24% soil water content) in pots. Macronutrient concentrations and contents of both old and new foliar tissue were determined. Decreasing soil water content resulted in higher concentrations of phosphorus, potassium, and particularly nitrogen in both old and new foliar tissue. This can be attributed to reduced growth, translocation, metabolic activity, and nutrient requirement in response to moisture stress. Seedlings with relatively higher root volumes exhibited higher nutrient concentrations and contents, as well as increased growth. Thus, increased total root biomass per unit of soil area with increasing seedling root volume may have resulted in greater nutrient use, supply, uptake, and storage.  相似文献   

Influence of soy aglycon isoflavones on bone-related traits and lens protein characteristics of ovariectomized rats and bioactivity performance of osteoprogenitor cells     

Lien TF  Chen W  Hsu YL  Chen HL  Chiou RY 《Journal of agricultural and food chemistry》2006,54(21):8027-8032

Health benefits of soy isoflavones have attracted the concern of the public and the interest of health-care professionals. In this study, two trials were conducted in characterizing bone-related traits and lens proteins as affected by supplementation of soy aglycon isoflavones (SAI). In trial 1, an in vivo study, 20 Sprague-Dawley rats were ovariectomized (OVX) and randomly distributed into OVX and OVX+SAI (135 mg of SAI/kg of feed; 8.33 mg/kg body weight; 2.5 mg/day) groups. Another group containing 10 rats with a sham operation was control (Sham). The experiment period was 3 months, and the rats were subjected to bone-related traits and lens protein characterization. In trial 2, an in vitro study, osteoprogenitor cells (UMR-106) were divided into SAI-supplemented (0.5 mg of SAI/mL of medium) and unsupplemented groups. Results of the in vivo study indicated that daily BW gains in the OVX and OVX+SAI groups were greater than that of the Sham group (p < 0.05). Bone ash and Ca contents of the Sham and OVX+SAI groups were higher than those of the OVX group (p < 0.05), while bone density, strength, and phosphorus contents among groups varied insignificantly (p > 0.05). When the lens proteins were extracted and analyzed with size-exclusion HPLC, the contents of beta- and gamma-crystallins were lowest in the OVX group and the protein solubility decrease could be recovered by dietary SAI supplementation (shown by OVX+SAI group). Based on Raman spectra of the isolated lens proteins, disulfide bonds were observed more in OVX lens than in the Sham and OVX+SAI lens. Results of in vitro study with osteoprogenitor cells revealed that cell viability, alkaline phosphatase activity, osteocalcin, and Ca contents of the SAI-supplemented group were higher than those of the unsupplemented group (p < 0.05). The likely potency to enhance bone and lens health by SAI supplementation is worth pointing out.  相似文献   

A comparison of Shiga-toxin negative Escherichia coli O157 aflagellate and intimin deficient mutants in porcine in vitro and in vivo models of infection     

Best A  La Ragione RM  Clifford D  Cooley WA  Sayers AR  Woodward MJ 《Veterinary microbiology》2006,113(1-2):63-72

Isolation of Shiga-toxin (Stx) positive Escherichia coli O157:H7 from commercially grown pigs has been reported. Furthermore, experimental infection studies have demonstrated that Stx-positive E. coli O157:H7 can persist in 12-week-old experimentally orally inoculated conventional pigs for up to 2 months and that persistence was not dependent upon intimin. We have shown that the flagellum of Stx-negative E. coli O157:H7 does not have a role to play in pathogenesis in ruminant models whereas, in poultry, the flagellum of E. coli O157:H7 was important for long-term persistent infection. The contribution of the flagellum of Stx-negative E. coli O157 in the colonisation of pigs was investigated by adherence assays on a porcine (IPI-21) cell line, porcine in vitro organ culture (IVOC) and experimental oral inoculation of conventional 14-week-old pigs. E. coli O157:H7 NCTC12900nal(r) and isogenic aflagellate and intimin deficient mutants adhered equally well to IPI-21 cells. In porcine IVOC association assays, E. coli O157:H7 NCTC12900nal(r) was associated in significantly higher numbers to tissues from the caecum and the terminal rectum than other sites. The aflagellate and intimin deficient mutants significantly adhered in greater numbers to more IVOC gastrointestinal tissues than the parent. Groups of 14-week-old pigs were dosed orally with 10(10)CFU/10ml of either E. coli O157:H7 NCTC12900nal(r) or isogenic aflagellate and intimin deficient mutants and recovery of each test strain was similar. Histological analysis of pig tissues at post mortem examination revealed that E. coli O157 specifically stained bacteria were associated with the mucosa of the ascending and spiral colon. These data suggest that colonisation and persistence of Stx-negative E. coli O157:H7 in pigs, involves mechanisms that do not require the flagellum or intimin.  相似文献   

The detection of Mycoplasma (formerly Eperythrozoon) wenyonii by 16S rDNA PCR and denaturing gradient gel electrophoresis     

McAuliffe L  Lawes J  Bell S  Barlow A  Ayling R  Nicholas R 《Veterinary microbiology》2006,117(2-4):292-296

Although the role of Mycoplasma wenyonii in disease is still subject to some debate, infections have been reported to result in parasitaemia, anaemia, scrotal and hind limb oedema, tachycardia, pyrexia, infertility, swollen teats, prefemoral lymphadenopathy and decreased milk production. Previously, diagnosis of M. wenyonii has been based on blood smears but is not specific for M. wenyonii and can be difficult to interpret. We have previously described the use of PCR and denaturing gradient gel electrophoresis (DGGE) for the detection and differentiation of Mycoplasma species. DGGE enables the rapid and specific identification of Mycoplasma species and is ideally suited to detecting both mixed infections and new and unusual species. In this study, we have used DGGE with universal primers to detect M. wenyonii DNA from blood samples. DGGE can be used on blood samples as a rapid and specific test for M. wenyonii and can also be used as a screening test for other blood borne pathogens.  相似文献   

Forced resonant migration of Pluto's outer satellites by Charon     

Ward WR  Canup RM 《Science (New York, N.Y.)》2006,313(5790):1107-1109

Two small moons of Pluto have been discovered in low-eccentricity orbits exterior to Pluto's large satellite, Charon. All three satellite orbits are nearly coplanar, implying a common origin. It has been argued that Charon formed as a result of a giant impact with primordial Pluto. The orbital periods of the two new moons are nearly integer multiples of Charon's period, suggesting that they were driven outward by resonant interactions with Charon during its tidal orbital expansion. This could have been accomplished if Charon's orbit was eccentric during most of this orbital evolution, with the small moons originating as debris from the collision that produced Charon.  相似文献   

Biosynthesis enhancement and antioxidant and anti-inflammatory activities of peanut (Arachis hypogaea L.) arachidin-1, arachidin-3, and isopentadienylresveratrol     

Chang JC  Lai YH  Djoko B  Wu PL  Liu CD  Liu YW  Chiou RY 《Journal of agricultural and food chemistry》2006,54(26):10281-10287

Peanut is a potent plant to be induced to synthesize bioactive stilbenoids. Bioactivities of those stilbenoids except resveratrol have been meagerly investigated. When peanut kernels (Tainan 14, a Spanish cultivar) were imbibed, incubated 3 days for germination, sliced, incubated with artificial aeration, periodically sampled, lyophilized, extracted with methanol, and subjected to reverse-phase HPLC analysis, four major fractionations were detected and identified as trans-resveratrol (Res), trans-arachidin-1 (Ara-1), trans-arachidin-3 (Ara-3), and trans-isopentadienylresveratrol (IPD). During incubation of the peanut slices, contents of Res, Ara-1, and Ara-3 increased tremendously from initially trace or not detectable amounts up to 147.3, 495.7, and 2414.8 microg/g, corresponding to 20, 16, and 24 h of incubation, while IPD contents continued to increase up to 28 h (4474.4 microg/g). When the four stilbenoids and butylated hydroxytoluene (BHT) were subjected to antioxidant characterization by various measures, all have exhibited varied potencies of antioxidant activity. In particular, retardation of absorbance increase at 234 nm as formation of the conjugated diene hydroperoxides in a real pork oil system stored at 60 degrees C, supplement of Ara-1 at 100 microM has shown equivalent or even greater activity than did BHT. When the media were supplemented with Res, Ara-1, Ara-3, and IPD at 15 microM for cultivation of mouse macrophage RAW 264.7 cells activated by lipopolysaccharide (LPS), the LPS-induced extracellular production of prostaglandin E2 (PGE2) and nitric oxide (NO) was significantly inhibited by Ara-1 (p < 0.001), Res (p < 0.001), Ara-3 (p < 0.01), and IPD (p < 0.01). It is noteworthy and of merit that all test stilbenoids have exhibited potent antioxidant and anti-inflammatory activities and varied as affected by number of hydroxyl groups and isopentenyl or isopentadienyl moiety. Keywords: Arachis hypogaea L.; peanut; groundnut; resveratrol; stilbenoids; arachidin; antioxidant; anti-inflammation.  相似文献   

Broad spectrum antimicrobial activity of leukocyte extracts from the American alligator (Alligator mississippiensis)     

Merchant ME  Leger N  Jerkins E  Mills K  Pallansch MB  Paulman RL  Ptak RG 《Veterinary immunology and immunopathology》2006,110(3-4):221-228

Leukocytes were isolated from whole blood of wild alligators by differential sedimentation. The leukocytes were disrupted in 5% AcOH and the crude extracts processed by ultrafiltration. The extracts were subjected to solvent exchange (0.1% AcOH) and the fraction that contained macromolecules between 1 and 10 kDa were subjected to further analyses. The acid extracts of the alligator leukocytes exhibited substantial antimycotic activities against six of eight species of Candida yeast tested. In addition, the alligator leukocyte extracts were effective as antimicrobial agents against 10 of 12 bacterial species, and displayed moderate activity against two enveloped viruses (human immunodeficiency virus-1 and herpes simplex virus-1_HF). Kinetic analyses revealed that the antimycotic effects of the leukocyte extract occurred rapidly, with 64% fungal growth inhibition within 3 min of exposure. The molecule(s) responsible for the antimicrobial activities were sensitive to proteases, heat-stable, acid soluble, and in the 1–10 kDa range. These data suggest that alligator leukocytes express cationic peptides that are responsible for their antimicrobial properties.  相似文献   

Molecular tools--advances, opportunities and prospects     

Gasser RB 《Veterinary parasitology》2006,136(2):69-89

Modern molecular technologies are having a substantial impact in many fundamental and applied areas of parasitology. In particular, polymerase chain reaction (PCR)-coupled approaches have found broad applicability because their sensitivity permits the enzymatic amplification of gene fragments from minute quantities of nucleic acids from tiny amounts of parasite material. Also, high-resolution electrophoretic and genomic methods are finding increased utility. This paper briefly discusses some developments and applications of DNA methods to parasites and highlights their usefulness or potential for those of veterinary importance. Selected examples of applications with implications in fundamental (systematics, population genetics, epidemiology and ecology) and applied (diagnosis, prevention and control) areas are presented. The focus is mainly on tools for the accurate identification of parasitic nematodes and protozoa of socio-economic importance, the diagnosis of infections and the detection of genetic variability using PCR-coupled mutation scanning technology.  相似文献   

Wilderness Image: Aconitum napellus,beautiful but deadly     

Robin J. Slaughter 《The Forestry Chronicle》2012,23(4):380

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