On the evolutionary significance of encephalization in some eutherian mammals: effects of adaptive radiation, domestication, and feralization.

Allometries of the brain to body size relationship in eutherian mammals are examined in this study as they can be used for comparative analyses concerning encephalization. In contrast with some modern presentations of this issue, an older concept is revived and expanded through this author's current study. Three allometries with clearly different slopes are valid and lead to reliable results: interspecific, intraspecific, and ontogenetic allometries. Interspecific allometries follow lines with slope values of 0.56 or 0.63 for larger and smaller species, respectively, and characterize different average encephalization plateaus with rodents and lagomorphs generally more strongly encephalized compared to basal insectivores. Artiodactyls, perissodactyls and carnivores as a whole are again on a higher but rather similar plateau. Several species of carnivores have reached different encephalization levels with respect to their average plateau indicating diverse radiations. A phylogenetic brain size increase from fossil to recent radiations is also evident. Intraspecific allometries have slope values of about 0.25. These are of help in comparing brain sizes of ancestral species with their domesticated relatives. Domestication has generally led to a brain size decrease, but species on higher encephalization plateaus show this trend more strongly than species on a lower level of encephalization. Several brain parts and the sense organs also decrease in size during the domestication process, but vary arbitrarily and to different degrees. Ontogenetic growth allometries are species-specific, but are especially different between altricial and precocial mammals. A very steep 1st phase slope of highly encephalized species is particularly useful for understanding evolutionary and adaptive phenomena. Domesticated mammals that have become feral do not show an increase in brain size despite living many generations in wild habitats.

Biological potency of porcine, bovine and human insulins in the rabbit bioassay system.

Potency determination of porcine, bovine and human insulins relative to the International Standard in the pharmacopoeial rabbit bioassay system requires that the log-dose response curves are parallel. Furthermore, the same relative potency should be obtained independent of how the hypoglycaemic response is defined. The results of 508 rabbit blood glucose assays have been analyzed by new multivariate statistical methods. No deviations from parallelism of the log-dose response curves were detected. However, the potencies showed significant variation depending on the blood sampling times. Pure porcine and human (semisynthetic and biosynthetic) insulin potencies decreased by 12% and 18%, respectively, from the 30-min to the 2.5-h response, whereas bovine insulin potencies increased by 9%. Since the standard is a 52:48 mixture of bovine and porcine insulins, these results could be due to porcine and human insulins having a quicker onset and shorter duration of hypoglycaemic effect than bovine insulin. This was confirmed in assays of bovine relative to porcine insulin and by direct comparison of mean blood glucose curves. It is concluded that there is a response time-dependent variation in potency when the test and standard insulin have a different species composition. Hence, pure species insulin standards - a porcine, a bovine and a human standard - are needed for assay of the three insulins.

Mycotoxin-producing potential of mold flora of dried beans.

To evaluate the potential for mycotoxin production by molds in dried beans, the mold flora of 114 samples was determined both before and after surface disinfection of the beans with 5% NaOCl. Surface disinfection substantially reduced mold incidence, indicating that contamination was mainly on the surface. The flora, both before and after disinfection, was dominated by species of the Aspergillus glaucus group, the toxicogenic species A ochracues, Penicillium cyclopium, and P. viridicatum, and species of Alternaria, Cladosporium, and Fusarium. The toxicogenic species Aspergillus flavis, A. versicolor, Penicillium Citrinum, P. expansum, P. islandicum, and P. urticae were encountered less frequently. Of 209 species of Aspergillus and Penicillium screened for mycotoxin production on sterile rice substrate, 114 produced one or more of the following mycotoxins: A. flavus, aflatoxins; A. ochraceus, ochratoxins; A. nidulans, A. unguis, and A. versicolor, sterigmatocystin; P. cyclopium, penicillic acid; P. citrinum and P. viridicatum, citrinin; P. urticae, patulin and griseofulvin. Sterigmatocystin production by A. unguis is reported for the first time.