Natural products specimens

The first step in discovering a marine natural product lead compound involves accumulating collections of the source organisms. Ideally the collections would include as many species as possible collected from a large number of sites reflecting the wide diversity of habitats found in the world s oceans. The development of SCUBA and both manned and remotely operated (ROV) submersibles has provided the technology required to effectively collect algae and invertebrate specimens from most marine habitats. Consequently, the major issue... 

Koike, Y., Wada, K., Kusano, G., Nozoe, S. Yokoyama, K. (1981). Isolation of psilocybin from Psilocybe argentipes and its determination in specimens of some mushrooms. Journal of Natural Products, 44, 362-365. 

Leather is a natural product and is subject to extensive variability. The physical and chemical properties vary considerably depending on the location from which the leather test sample is taken. The standard test method from the American Society for Testing and Materials (ASTM D2813, 1997) ensures random sampling of finished leather and fabricated leather items for physical and chemical tests. Test specimens should be cut from only one side of the backbone with their long dimension perpendicular to the backbone line. Test specimens should be taken from different parts of the shoulder, belly and tail of the leather. The number of specimens taken depends on the reliability of the test results, the deviation and the error of the testing procedures and should be recorded on the test report. Physical tests of leather and leather products, unless otherwise specified, should be performed under the standard atmospheric conditions of 50 4% relative humidity at 23 1 °C. 

Another problem is posed by the fact that the number of known species that can be collected in large quantities (often those species considered pests) represents only a small fraction of overall arthropod species diversity. Most arthropod species are rare, and can only be collected sporadically, often with dramatic seasonal or yearly variations in availability. It is unfortunately all too common to identify what appears to be a promising species for further research, often with considerable investment of time in collecting preliminary data, only to realize subsequently that additional specimens cannot be obtained. This problem is compounded by the fact that many insect species are difficult or even impossible to raise in captivity. Such instances bring to the foreground what may be the biggest challenge in insect natural products research lack of sufficient sample amounts for detailed analyses. 

The root bark yielded l-isobutyl-l,2,3,4-tetrahydro-j3-carboline (B.HCl, mp 257-259°). A synthetic specimen prepared by the condensation of tryptamine with isovaleraldehyde was identical with the natural product (89). 

In fact, the one feature most preventive to the application of the enormous amount of natural product chemistry data in life sciences is that these data are nearly always determined on populations of organisms as opposed to individuals. Most often the populations are not even clones but represent genetically different specimens. As discussed later there may be large individual chemical variations in specimens of a given population. At present we are also badly in need of more specific information regarding the location (organ or organelle) of metabolites. 

The sea hare Dolabella auricularia (Aplysiidae) has been extensively investigated as a rich source of bioactive natural products, and a number of bioactive peptides and depsipeptides such as dolastatin 10 were isolated from both Western Indian Ocean specimens and Japanese specimens of this animal [for example, 134, 135]. This mollusk was also found to contain macrolide-type natural products. From D. auricularia, collected by hand at a depth of 0-1 m off the coast of the Shima Peninsula, Mie Prefecture, Japan, a 22-membered macrolide, dolabe-lide A (65), was isolated as a cytotoxin with an IC50 value of 6.3 pg/ml against HeLa-S3 cells. The gross structure of 65 was determined by spectroscopic analysis, and its absolute stereochemistry was elucidated by a combination of chemical means and the NMR spectroscopic method [136]. 

As with all specimens collected for natural products research, all collections of marine organisms should be made with the informed consent of the host country or state. Permits are required for most collections of marine organisms and come under local and/or federal laws. Some marine species are protected by CITES and cannot be collected or exported without special permits. A review by Baker et al. (22) outlines general philosophies and policies with respect to the collection of both terrestrial and marine organisms. 

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