Harvesting Samples

Sampling can be as simple as picking fruit from a tree and digging potatoes from the ground or as complex as harvesting with a mechanical harvester. Samples should be harvested is such a way as to prevent bias in the samples (OPPTS 860.1500, p. 2). 

Table IV gives the data from seven plots of Winesap and Rome Beauty apples in the Mississippi Valley. The spray schedules are similar to those used for the plots included in Table III, except that an additional parathion spray was applied on plots 9, 11, 14, and 4 on August 19, and the final harvest sample was taken on October 5. Only on the plot that was sprayed seven times with the 8-ounce strength of parathion (plot 14) did the spray residue at harvest approximate 0.1 p.p.m.

Harvested samples should be immediately prepared for the SEM by fixation in a 0.5% osmium tetroxide solution in the dark for 1 h. If the sample is collected in the field, store in buffered 3% glutaraldehyde solution (pH 7.2) until samples can be fixed. 

An important finding of USGS research was the occurrence of triazine herbicides in surface water. In a study by Thurman et al. (1991, 1994) measurable amounts of atrazine, the most frequently detected herbicide, occurred in 91% of the pre-planting samples, 98% of the post-planting samples, and 76% of the harvest samples. The atrazine degradation product DEA was found in many of the samples that contained atrazine. The frequency of detection or apparent order of stability of the herbicides and their degradation products is as follows atrazine, DEA, DIA, and cyanazine. This stability order is based on results of field-dissipation studies on atrazine and cyanazine (Meyer, 1994 Mills and Thurman, 1994). 

To terminate the assay and harvest samples for quantitative analysis of HBV virion DNA, remove the culture medium 24 h following d 9 of treatment, and store the culture medium in 96-well U-bottomed culture plates. Cover the U-bottomed plates tightly with parafilm to prevent evaporation. Store these samples at 4°C until blotting is performed. Samples can eventually be transferred to -20°C for long-term storage. 

Fig. 6.7 TMAE analytical HPLC chromatogram, showing 260 nm absorbance traces of an non-in-fected cell harvest control (A) and adenovirus infected cell harvest sample (B). Chromatograms were generated using a HP 1100 system with a Fractogel EMD Tentacle Ion-Exchanger resin in a...

One amino acid, aspartic acid, whose concentration changes are shown in Figure 4 shows quite different responses to the other amino acids. Here the two prematurely harvested samples (El, E2) show an increase in aspartic acid concentration on storage but that harvested fiilly ripe shows a decrease. 

Virus loads in unprocessed, prepurified bulk (harvest samples) are quantified, typically via transmission by electron microscopy or infectivity, to estimate actual virus load versus the expected virus removal capacity of the process [47,50]. Total virus clearance should exceed measured levels by at least 3-5 logs [47]. An example of a typical virus load is 10 to 10 RVLPs (retrovirus-like particles) per milliliter of unprocessed bulk from CHO cells [3]. Clearance factors of 15-20 logs are typical for murine retroviruses [3] and slightly more than for lipid-enveloped viruses. For most viruses besides endogenous retroviruses, however, there is no reasonable way to establish virus load in the bulk because these types of viruses should not normally be present. In addition direct testing methods are limited inherently because they are designed to detect only known and not known contaminants [5]. Thus, the... 

Carrots were harvested by hand and shipped unwashed to NRRC in plastic bags. Analysis of the four varieties was completed 1 to 2 weeks after each harvest sample was received. Carrots grown in Illinois (NRRC) were harvested by hand and analyzed immediately. 

Harvest samples, wash quickly in IX PBS, and then flash freeze in liquid nitrogen. These samples can then be stored at -70°C or used immediately for mRNA isolation... 

Peas grow best on well-drained loams and lighter soils. The pH should be aborrt 6-6.5 if it is too high, manganese deficiency is likely and may reduce the quahty of the harvested sample. Lodging may be a problem where fertility is high and so suitable varieties should be chosen. 

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