Amino acid transport by small and large intestine of newborn pig

Summary Unidirectional fluxes of different amino acids have been determined across newborn pig small intestine and colon. The systems responsible for amino acid transport are present in the same proportion in both tissues. Colonic transport of amino acids appears to represent a transient overspill function of the small intestine.     

Status and distribution of the Fish Creek Springs tui chub, Gila bicolor euchila

The Fish Creek Springs tui chub, Gila bicolor euchila , is present in large numbers throughout its native habitat in spite of extensive man-caused habitat disturbance. This subspecies occurs further downstream in Fish Creek than previously reported.       

Reproductive traits in the northern scorpion ( Paruroctonus boreus )

Despite its large geographic range, little is known about reproductive traits in the northern scorpion ( Paruroctonus boreus ). We analyzed reproductive traits for 36 females from a population near Billings, Montana. All data were collected within a single year. Litter size, offspring mass, total litter mass (TLM), and relative litter mass (RLM) were within the ranges of values reported for other species in the Vaejovidae. Female size (length or mass) was not correlated with any reproductive trait. Litter size and offspring mass were each positively correlated with RLM, suggesting that females investing relatively larger amounts of energy in reproduction increase both size and number of offspring. Finally, the within-litter coefficient of variation in offspring mass was negatively correlated with RLM, TLM, and mean offspring mass, suggesting that females investing more energy in reproduction produce more-uniformly sized offspring, an observation that appears common in scorpions.     

Human fatalities caused by venomous animals in Utah, 1900-90

An examination of death certificates at the Utah Bureau of Health Statistics from 1900 through 1990 indicates that Utah has a very low incidence of human fatalities due to venomous bites and stings. During this 91-year period, 20 fatalities were recorded from bee (10) or hornet (1) stings, spider bites 94), and rattlesnake bites (5). There were eight additional fatalities during the early part of this century recorded "insect bite," "apparently insect bite," or "unknown agent poisoning," some of which may have included spiders. No deaths were recorded from Gila monster or scorpion evenomizations, although in 1962 one death in San Juan County was recorded as "venom poisoning, unknown agent, possible scorpion." Utah statistics follow the natural pattern, indicating that bee stings cause more fatalities than spider or rattlesnake bites. Raid deaths (within minutes) occurred in the majority of bee sting fatalities, resulting from allergic reactions (anaphylaxis), whereas protracted death times of days or months, resulting from infection, followed most spider or unknown insect bites. Only two spider bite fatalities occurred 1-3 days, suggesting black widow envenomization. Two of the five fatalities from rattlesnake bite resulted from handling the offending snake, one fatality was recorded as a homicide, and one other envenomization occurred in Arizona, with subsequent death in Utah.     

The principle of rigidification

Communicated by C. Truesdell & H. J. M. Bos     

Molecular structure of an aspartic proteinase zymogen, porcine pepsinogen, at 1.8 A resolution

The only well-understood mechanism of zymogen activation is that of the serine proteinases, in which proteolytic cleavage leads to conformational changes resulting in a functional active site. A different mechanism is now unveiled by the crystal structure of pepsinogen. Salt bridges that stabilize the positioning of the N-terminal proenzyme segment across the active site of pepsin are disrupted at low pH, releasing the amino-terminal segment and thereby exposing the catalytic apparatus and the substrate-binding sites.