scholarly journals Soil Heterotrophic Respiration Potential and Maximum Respiration Rate of Differently Managed Meadows

2013 ◽  
Vol 1 (No. 4) ◽  
pp. 153-157
Author(s):  
Formánek Pavel ◽  
Vranová Lukáš Kisza and Valerie
Keyword(s):  
Respiration Rate ◽  
Soil Samples ◽  
Sampling Time ◽  
Sampling Occasion ◽  
Glucose Addition ◽  
Soil Heterotrophic Respiration ◽  
C Mineralisation ◽  
Mountain Meadows ◽  
Sampling Times ◽  
Respiratory Potential

In this study were compared heterotrophic respiratory potential (VDS/VMAX) expressing an increase in C mineralisation rate after drying and re-wetting the soil to 60% soil water content (v/w)(VDS) in relation to maximum respiration rate (VMAX) after glucose addition, and VMAX in organomineral soil (Ah horizon) of mod­erately mown and for 11 years abandoned mountain meadows in Moravian-Silesian Beskids Mts. VDS/VMAX and VMAX were assessed in soil samples taken in 30-day intervals throughout the period of May–September 2004. The results obtained showed higher VDS/VMAX on the abandoned meadow throughout the whole experiment except the last sampling occasion, and higher VMAX throughout the whole experiment. Significantly (P < 0.05) higher VDS/VMAX on the abandoned meadow was found in May and July, VMAX was significantly higher on the same meadow (P < 0.05) only in September. From the parameters studied, the time of sampling had no significant (P > 0.05) effect on VMAX when the data from the moderately mown meadow were evaluated. On the abandoned meadow, VMAX found was significantly (P < 0.05) different when the samples from May and September or July and September were compared. A significant (P < 0.05) effect of the sampling time on VDS/VMAX on the moderately mown meadow was presented by differences between May and other sampling times, on the abandoned meadow differences between September and other times of sampling except May were significant (P < 0.05).

scholarly journals The 28 + 28 day design is an effective sampling time for analyzing mutant frequencies in rapidly proliferating tissues of MutaMouse animals

2021 ◽  
Vol 95 (3) ◽  
pp. 1103-1116
Author(s):  
Francesco Marchetti ◽  
Gu Zhou ◽  
Danielle LeBlanc ◽  
Paul A. White ◽  
Andrew Williams ◽  
...  
Keyword(s):  
Germ Cells ◽  
False Negative ◽  
Sampling Time ◽  
Male Germ Cells ◽  
Negative Results ◽  
False Negative Results ◽  
Detection Of Mutations ◽  
The Impact ◽  
Sampling Times

AbstractThe Organisation for Economic Co-Operation and Development Test Guideline 488 (TG 488) uses transgenic rodent models to generate in vivo mutagenesis data for regulatory submission. The recommended design in TG 488, 28 consecutive daily exposures with tissue sampling three days later (28 + 3d), is optimized for rapidly proliferating tissues such as bone marrow (BM). A sampling time of 28 days (28 + 28d) is considered more appropriate for slowly proliferating tissues (e.g., liver) and male germ cells. We evaluated the impact of the sampling time on mutant frequencies (MF) in the BM of MutaMouse males exposed for 28 days to benzo[a]pyrene (BaP), procarbazine (PRC), isopropyl methanesulfonate (iPMS), or triethylenemelamine (TEM) in dose–response studies. BM samples were collected + 3d, + 28d, + 42d or + 70d post exposure and MF quantified using the lacZ assay. All chemicals significantly increased MF with maximum fold increases at 28 + 3d of 162.9, 6.6, 4.7 and 2.8 for BaP, PRC, iPMS and TEM, respectively. MF were relatively stable over the time period investigated, although they were significantly increased only at 28 + 3d and 28 + 28d for TEM. Benchmark dose (BMD) modelling generated overlapping BMD confidence intervals among the four sampling times for each chemical. These results demonstrate that the sampling time does not affect the detection of mutations for strong mutagens. However, for mutagens that produce small increases in MF, sampling times greater than 28 days may produce false-negative results. Thus, the 28 + 28d protocol represents a unifying protocol for simultaneously assessing mutations in rapidly and slowly proliferating somatic tissues and male germ cells.

scholarly journals Impact of Exposure to Low Temperature Degrees in Field Conditions on Leaf Pigments and Chlorophyll Fluorescence in Leaves of Mango Trees

2020 ◽  
Vol 10 ◽  
pp. 30-45
Author(s):  
Ali A.S. Sayed ◽  
Farouk M. Gadallah ◽  
Mohamed A. Seif El-Yazal ◽  
Gamal A. Abdel-Samad
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
Chlorophyll Concentration ◽  
Ambient Air ◽  
Sampling Time ◽  
Chlorophyll B ◽  
Physiological And Biochemical ◽  
Sampling Times ◽  
Fayoum Governorate

This experiment was conducted to found the connection between low temperature stress in vivo conditions (ambient-air temperature) and the changes in some physiological and biochemical events (leaf pigments and chlorophyll fluorescence) of mango trees in response to exposure to natural low temperature (cold). To verify this objective, 12 popular commonly mango cultivars (25 years old) which grown in private orchard in Fayoum Governorate, Egypt were selected for this study which carried out during the period from November to March of years; 2012 and 2013. The selected cultivars were: Alphonso, Baladi, Bullock's Heart, Helmand, Hindi Besennara, Mabrouka, Mestekawy, Nabeeh, Oweisi, Spates, Taimour and Zebda. Based on the obtained results, it can be stated that, chlorophyll (a) concentration in the leaves was significantly differed among the cultivars throughout the whole sampling times, in this respect, Helmand one gave the highest one while, and the highest one by sampling times was November one. The concentration of chlorophyll (b) was significant as effected by the effect of cultivars and sampling time recorded the highest value by the cultivar of Spates and December sample, respectively. Total chlorophyll concentration in the leaves reached its peak by the cultivar of Nabeeh and sampling time of December as compared to others. The both of Ewais cultivar and the sample of March showed the highest values of carotenoids concentration in the leaves. The levels of anthocyanin in leaves were significantly differed as affected by the cultivars and sampling times, indicating that the cultivar of Helmand and November sample recorded the highest values of anthocyanin in leaves. The greatest reductions in Fv/Fmratio were recorded at month of November and indicated that the reductions were in the order of Alphonso˃ Mabrouka˃Taimour˃ others. The effect of sampling time, cultivars and their interaction on Fv/Fm were significant, but small between some values of Fv/Fm.

Comparison of Two Sampling Methods for Escherichia coli O157:H7 Detection in Feedlot Cattle

2005 ◽  
Vol 68 (8) ◽  
pp. 1724-1728 ◽  
Author(s):  
M. L. KHAITSA ◽  
M. L. BAUER ◽  
P. S. GIBBS ◽  
G. P. LARDY ◽  
D. DOETKOTT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sampling Methods ◽  
Feedlot Cattle ◽  
Sampling Time ◽  
Escherichia Coli O157 ◽  
Confounding Factors ◽  
Rank Tests ◽  
E Coli ◽  
Signed Rank ◽  
Sampling Times

Two sampling methods (rectoanal swabs and rectal fecal grabs) were compared for their recovery of Escherichia coli O157:H7 from feedlot cattle. Samples were collected from 144 steers four times during the finishing period by swabbing the rectoanal mucosa with cotton swabs and immediately obtaining feces from the rectum of each individual steer. The number of steers with detectable E. coli O157:H7 increased from 2 of 144 (1.4%) cattle on arrival at the feedlot to 10 of 144 (6.9%) after 1 month, 76 of 143 (52.8%) after 7 months, and 30 of 143 (20.8%) at the last sampling time before slaughter. Wilcoxon signed-rank tests indicated that the two sampling methods gave different results for sampling times 3 and 4 (P < 0.05) but not for sampling time 2 (P = 0.16). Agreement between the two sampling methods was poor (kappa < 0.2) for three of the four sampling times and moderate (kappa = 0.6) for one sampling time, an indication that in this study rectoanal swabs usually were less sensitive than rectal fecal grabs for detection of E. coli O157:H7 in cattle. Overall, the herd of origin was not significantly associated with E. coli O157:H7 results, but the weight of the steers was. Further investigation is needed to determine the effects of potential confounding factors (e.g., size and type of swab, consistency of feces, site sampled, and swabbing technique) that might influence the sensitivity of swabs in recovering E. coli O157:H7 from the rectoanal mucosa of cattle.

316 Does sampling time matter? Relationships of circulating metabolites at various neonatal sampling times in beef calves

2016 ◽  
Vol 94 (suppl_2) ◽  
pp. 148-149
Author(s):  
J. M. Larson ◽  
B. L. Vander Ley ◽  
S. M. Bolen ◽  
N. B. Duncan ◽  
A. M. Meyer
Keyword(s):  
Sampling Time ◽  
Beef Calves ◽  
Sampling Times

scholarly journals Sarpa salpa herbivory on shallow reaches of Posidonia oceanica beds

2014 ◽  
Vol 37 (1) ◽  
pp. 49-57 ◽  
Author(s):  
L. Steele ◽  
◽  
K. M. Darnelli ◽  
J. Cebrián ◽  
J. L. Sánchez-Lizaso ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Leaf Area ◽  
Posidonia Oceanica ◽  
Sampling Time ◽  
Herbivorous Fish ◽  
Small Scale ◽  
Bite Size ◽  
Sarpa Salpa ◽  
Sampling Times

Here, we examined the temporal and small–scale spatial variability of grazing by the herbivorous fish Sarpa salpa on shallow beds of the temperate seagrass Posidonia oceanica. Herbivory intensity expressed as the percent of leaf area taken by fish bites was higher in September 2006 than in February 2007, and at 0.5 m than at 1.5 m during both sampling times. All S. salpa feeding at the shallow locations studied were juveniles, with bite sizes ranging from 0.03 to 0.62 cm2. Juveniles feeding at 1.5 m were larger in February 2007 than in September 2006, as evidenced by significant differences in mean bite size per shoot. However, the larger juveniles feeding at 1.5 m in February 2007 did not appear to feed as frequently as the comparatively smaller juveniles feeding at the same depth in September 2006, as suggested by significant differences in number of bites per shoot. The number of bites per shoot was also lower at 1.5 m than at 0.5 m in February 2007, although mean bite size did not differ significantly between the two depths at that sampling time. In general S. salpa juveniles did not select a particular range of leaf ages when feeding in the study locations, although the juveniles feeding at 1.5 m in September 2006 appeared to select mid–aged leaves. Fish did not show a preference for more epiphytized leaves. These results show that grazing activity by S. salpa juveniles in shallow reaches of P. oceanica meadows may vary temporally and across small changes in depth, which in turn may affect the overall intensity of herbivory on the seagrass.

scholarly journals Novel Primers and Sampling for PCR Detection of Xylella fastidiosa in Peach

2019 ◽  
Vol 109 (2) ◽  
pp. 307-317 ◽  
Author(s):  
Chunxian Chen ◽  
Clive H. Bock ◽  
Phillip M. Brannen
Keyword(s):  
Prunus Persica ◽  
Xylella Fastidiosa ◽  
Southeastern United States ◽  
Sampling Time ◽  
Pcr Detection ◽  
Detection Sensitivity ◽  
Tissue Type ◽  
Conventional Pcr ◽  
Reliable Detection ◽  
Sampling Times

Epidemics of phony peach disease (PPD), caused by Xylella fastidiosa, are of increasing concern to peach (Prunus persica) producers in the southeastern United States. Primers suitable for both conventional PCR (cPCR) and quantitative PCR (qPCR), along with optimal tissue and sampling time, are needed for comparative and reliable detection of X. fastidiosa. In this study, we developed and assessed novel primers for X. fastidiosa and for peach and compared detection of X. fastidiosa in four peach tissue types sampled at three time points using both cPCR and qPCR. Primer C06Xf-bamA was extensively tested for reliable detection of X. fastidiosa due to the more consistent intensity of the cPCR products and the marginally lower average quantification cycle (Cq) values of the qPCR products, compared with the other primers screened. Among the four peach tissue types tested, only root samples demonstrated reliable and consistent detection of X. fastidiosa; stem, petiole, and leaf samples, regardless of source trees, primers used, sampling times, or PCR methods (cPCR or qPCR), were unreliable for detection, due to insufficient quantity of DNA of X. fastidiosa in these samples based on the relative quantification assay. The Cq means and ratios were compared and statistically analyzed, to ascertain effects of source tree, tissue type, sampling time, and primer. Differences in detection sensitivity and the Cq means among sampled trees, sampling times, tested primers, and tissues (except root) were not significant or were inconsistent precluding further exploitation. In summary, these novel primers are a useful resource for detecting X. fastidiosa, and based on our results, root is the only tissue type reliable for year-round detection of X. fastidiosa in peach. Further research on potential utilization of above-ground tissues for PCR detection of X. fastidiosa are discussed.

Validation of saliva and urine use and sampling time on the doubly labelled water method to measure energy expenditure, body composition and water turnover in male and female cats

2020 ◽  
Vol 124 (4) ◽  
pp. 457-469
Author(s):  
Camila Goloni ◽  
Francine M. Peres ◽  
Igor L. S. Senhorello ◽  
Ludmilla G. Di Santo ◽  
Fernanda S. Mendonça ◽  
...  
Keyword(s):  
Body Composition ◽  
Energy Expenditure ◽  
Sampling Time ◽  
Isotope Enrichment ◽  
Water Turnover ◽  
Doubly Labelled Water ◽  
Male And Female ◽  
Before And After ◽  
Linear Elimination ◽  
Sampling Times

AbstractLess invasive protocols are necessary to study energy expenditure (EE) of cats living in homes for expressing their normal living conditions. The present study compared sampling times and the use of saliva, urine and blood to measure 2H and 18O to apply the doubly labelled water method. In the first study, four cats were used to evaluate the enrichment (2, 4, 6, 7 and 8 h) and elimination (2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 d) of 2H and 18O (subcutaneously injected). The maximum enrichment was after 5 h (R2 0·82) of injection, with an Ln linear elimination of both isotopes (P < 0·001; R2 0·99). The results of EE were similar, regardless of the sampling time used (P = 0·999). In the second study, seven male cats and seven female cats were used. Before and after isotope injection (5 h, 7 d, 10 d and 14 d), blood, saliva and urine were collected. Isotope enrichment was lower in urine (P < 0·05) and at the similar level in blood and saliva. Isotope elimination was similar for all fluids (P < 0·473). The EE calculated with blood and saliva was similar but higher for urine (P = 0·015). According to Bland–Altman statistics, blood and saliva presented low bias and high correlation (P < 0·001), but this was not observed for urine (P = 0·096). Higher EE was observed for male cats (384 (se 39) kJ/kg0·67 per d) than for female cats (337 (se 34) kJ/kg0·67 per d; P < 0·05). The sampling time for the method is flexible, and saliva can be used as a substitute for blood.

Changes in cortical and wood terpenes in Sitka spruce in response to wounding

2001 ◽  
Vol 31 (9) ◽  
pp. 1561-1568 ◽  
Author(s):  
J R Nault ◽  
Rene I Alfaro
Keyword(s):  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Sampling Time ◽  
Minor Effect ◽  
White Pine ◽  
Pissodes Strobi ◽  
Significant Difference ◽  
A Minor ◽  
Artificial Wounding ◽  
Sampling Times

Terpene levels were measured in bark and wood samples of Sitka spruce (Picea sitchensis (Bong.) Carrière) trees. The trees that had been selected as early or late flushing were subjected to artificial wounding to simulate attack by the white pine weevil, Pissodes strobi (Peck). Samples were taken at four times during the growing season: before wounding, shortly after wounding, and two times later in the season. Terpenes were extracted with hexane and quantified by capillary gas chromatography. There were no significant differences in total bark terpenes between early- and late-flushing trees or between control and wounded trees over all sampling times. There were no significant differences in total wood terpenes between early- and late-flushing trees or among sampling times, but a statistically significant difference was found between control and wounded trees. Eleven individual terpenes accounted for the majority of the terpenes in the extracts. Four bark terpenes showed significant differences with sampling time, two with flushing class, and none with treatment. Five wood terpenes showed significant differences with sampling time, two with flushing class, and nine with treatment. We concluded that flushing had only a minor effect on bark and wood terpene profiles and that wounding significantly increased terpene concentration in wood shortly after injury.

Implication of Temporal Dynamics of Microbial Abundance and Nutrients to Soil Fertility under Biochar Application – Field Experiments Conducted in a Brown Soil Cultivated with Soybean, North China

2012 ◽  
Vol 518-523 ◽  
pp. 384-394 ◽  
Author(s):  
Da Quan Sun ◽  
Meng Jun ◽  
Wei Ming Zhang ◽  
Xue Chao Guan ◽  
Yu Wei Huang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Fertility ◽  
Community Composition ◽  
Field Experiments ◽  
Microbial Community Composition ◽  
Sampling Time ◽  
Microbial Abundance ◽  
Total N ◽  
Brown Soil ◽  
Sampling Times

A short-term experiment was conducted to investigate responses of microbial community composition and nutrients dynamics to biochar-amended brown soil. We examined the effect of biochar on microbial abundance by plate counting method and microbial community composition changes by DGGE, as well as effect on total and available nutrients N, P and K content. Soil pH measurement was also incorporated into our study. The overall results showed that bacterial abundance increased more than actinomycetes, but fungal abundance decreased slightly in biochar amended soil in later sampling times. In terms of microbial community composition, DGGE analysis for bacteria exhibited some specific lanes in biochar treatments. Bacterial community was more sensitive to sampling time, but fungal community was influenced greatly by biochar addition. In our study, total C content increased significantly, as biochar rate and sampling time preceded. Total N increased slightly in later sampling time, and thus C and N ratio increase was obtained. Total P and K changes were not obvious. Extractable N and pH increased. Microbial utilization was assumed to contribute to extractable P and K decrease in later sampling times. Results suggested that biochar incorporation to brown soil might bring potential benefit to soil fertility from N retention in soil. Microbial turnover may feedback P and K to soil as well in the long term. There may also be an implication of beneficial effect on disease alleviation lead by microbial community imbalance.

scholarly journals Attributes of the soil with cactus pear under organic fertilization, different spacings and sampling times

2020 ◽  
Vol 24 (7) ◽  
pp. 444-450
Author(s):  
Milton C. Padilha Junior ◽  
Sérgio L. R. Donato ◽  
Paulo E. R. Donato ◽  
João A. da Silva
Keyword(s):  
Organic Matter ◽  
Block Design ◽  
Organic Fertilizer ◽  
Sampling Time ◽  
Organic Fertilization ◽  
Cactus Pear ◽  
Randomized Block Design ◽  
Chemical Attributes ◽  
Sampling Times ◽  
Different Doses

ABSTRACT The objective of this study was to evaluate the chemical attributes of the soil cultivated with ‘Gigante’ cactus pear under different doses of organic fertilizer, planting spacings and sampling times. Four doses of organic fertilizer with bovine manure (0, 30, 60 and 90 Mg ha-1 year-1), three spacings (1.0 x 0.5, 2.0 x 0.25 and 3.0 x 1.0 x 0.25 m) and three sampling times (0, 390 and 600 days after planting) corresponding to the periods prior to planting, growth and harvest of the first cycle, were evaluated in a randomized block design in a 4 x 3 x 3 factorial scheme, with three repetitions. The pH in water, macronutrients (P, K, Ca, Mg), micronutrients (B, Cu, Fe, Mn, Zn), variables of the soil sorption complex (H + Al, SB, CEC, T, V) and soil organic matter (SOM) were determined. Organic fertilization increased the values of SOM, P, K, Ca, Mg, SB, CEC, T and V and reduced H + Al in soils cultivated with ‘Gigante’ cactus pear at different times. The doses of manure increased pH and Mn, regardless of sampling time and spacing. The spacings did not influence the chemical attributes of the soil.

Sign in / Sign up

Export Citation Format

Share Document