Protease treatment of nuclear extracts distinguishes between class II MHC X1 box DNA-binding proteins in wild-type and class II-deficient B cells

The X box region is critical for directing the expression of class II major histocompatibility complex genes in B lymphocytes. Although several class II promoter-specific DNA binding factors have been described, only the X box region factor, RFX, shows a genetic correlation with class II expression, being deficient in some B cell lines derived from patients with class II-deficient congenital immunodeficiency. To further evaluate the role of X box DNA-binding proteins in class II gene expression, the role of the X box region was examined in both class II-positive and -negative lymphoid cells. In addition to the wild-type B cell line Raji, two class II transcriptional mutant cell lines, SJO and RJ2.2.5, and Jurkat, a class II negative T cell line, were examined. In contrast to wild-type B cells, neither of the class II mutant cell lines could use the X box region to direct the expression of a transiently transfected reporter gene, indicating that the X box-dependent transcriptional pathway is defective in these cells. The binding activity of the X1 box DNA-binding protein RFX was examined and found to be present in wild-type B cells and the mutant RJ2.2.5 but was absent in SJO and Jurkat. However, other X1 box-specific activities were detected in all these cell lines. To determine whether these different X1 box activities represented distinct DNA binding proteins or multimeric forms of the same factor(s), protease treatment of the crude nuclear extracts followed by DNA-binding assays were carried out and demonstrated that B cell extracts contain at least two X1-specific factors. One of these cleaved products (band 1 pk) correlates with RFX activity. A similar comparison with protease-treated extracts prepared from Jurkat cells demonstrated the presence of the band 1pk activity despite an absence of the native RFX activity. In contrast, protease treatment and analysis of SJO extracts showed no detectable levels of the band 1pk activity. These results demonstrate that multiple X1 box-specific DNA-binding activities exist in all lymphoid cells, but the presence of an actively binding RFX species correlates with class II transcription.

A radio telemetering capsule and demodulator for recording rumen motility

A new pressure sensitive capsule for monitoring rumen activity has been developed. Surgery on the animal is not required for introducing the unit because it is small enough to be placed in the rumen using a stomach tube. The unit will transmit for several weeks and uses an inexpensive, commercially available pressure transducer as a sensor.

Experimental toxoplasmosis in calves and pregnant cows

Experimental Toxoplasma gondii infections were studied in pregnant cows and in calves. In tests to compare their virulence, three strains of the toxoplasmal parasite were red to cats; then fecal oocysts were collected and given per os to calves. In tests to determine their effects, virulent tachyzoites or oocysts were given to 10 calves and to 22 pregnant cows by the oral, IV, or intraamniotic routes. Clinical signs were fever and inappetence. One cow in early gestation aborted 24 days after IV administration of tachyzoites. Gross and microscopic changes were slight and nonspecific. Toxoplasmas were isolaated from brain or liver of 4 cows, placenta of 2 cows, gastric contents of 2 near-term fetuses, and blood and tissues of calves. Toxoplasmas were not isolated from control cows.

A radiotelemetry transmitter for transmitting temperatures from small animals

A small, reliable temperature-telemetry transmitter was designed and tested for use in small laboratory animals. It transmits a continuous signal that makes it very reliable. It can be constructed of standard small parts and contains and electric watch battery as a source of power. Two models were developed. One transmits at 100 MHz and its signal can be received on a standard FM tuner. The other model transmits at 40 MHz and provides a longer battery life.

Effect of environmental temperature stress on intramammary infections of dairy cows and monitoring of body and intramammary temperatures by radiotelemetry

Four dairy cows were stressed by exposure to hot and cold environments in tests to determine the effect of environment on milk yield, somatic cell counts, and California mastitis test scores of milk from all mammary quarters and on bacterial counts of milk from infected quarters. Two cows were held in temperature-controlled rooms for successive 5-day periods at moderate (21 to 28 C), cold (-16 C), moderate, hot (36 to 37 C), and moderate environments. The cold and hot sequences were reversed for the other 2 cows. Temperature transmitters were surgically implanted in the skeletal muscles of the loin and gluteal regions; however, only one of these transmitters (gluteal region) functioned continuously throughout the experiment. At the end of this experiment, a transmitter was implanted in the gland cistern of a rear quarter of 1 cow, and the sequence of holding in the cold before the hot environment was used. Mean body temperature was approximately 1 degree higher (39.2 C) in the hot room (1 cow) and 3 to 4 degrees lower (35 C and 33 C), respectively, for 2 cows) in the cold room than that during the moderate temperature periods. A similar comparison showed that the mean intramammary temperature was 1 to 2 degrees higher (39.5 C) in the hot room and approximately 9 degrees lower (29.4 C) in the cold room. Exposure of the cows to hot and cold environments caused a greater loss in milk production in the 2 medium-yielding cows (23 to 28 kg/day) than in the 2 low-yielding cows (9 to 13 kg/day). The effect of the extreme temperatures on the somatic cell counts in uninfected quarters was limited to only a few quarters and was inconsistent (mean counts increased and decreased at both temperatures). The California mastitis test reactions showed no consistent changes during periods of heat and cold stress. Also, the effect of the environmental temperature on the intramammary infections also was inconsistent. The effect on bacterial counts appeared to vary with the type of organism. Some mean counts decreased in the heat and cold (Streptococcus agalactiae, Micrococcus sp), some increased (Pseudomonas sp), and another seemed independent (Streptococcus uberis) of the environmental temperature at which the cow was held.

Comparison of techniques for measuring the local and systemic responses to tuberculin in cattle

Thermography of tuberculin skin reactions in cattle sensitized with Mycobacterium avium, Mycobacterium bovis, or Mycobacterium paratuberculosis was rapid and sensitive, but was not as specifically related to the homologous sensitization as was increased skin thickness at 48 and 72 hours. Systemic temperature responses were more completely monitored by radiotelemetry of intraperitoneally located temperature transmitters than by rectal thermometry, but the temperatures indicated by the 2 methods were nearly identical. The intraperitoneal transmitters showed that the systemic responses consisted of 1, 2, or 3 temperature peaks, and in 1 animal which had previously been exposed to a heterologous tuberculin, a hypothermic response developed. The systemic temperature responses were more specifically related to homologous sensitization than were dermal responses, but were more cumbersome to measure.

Upper respiratory infection of lactating sows with transmissible gastroenteritis virus following contact exposure to infected piglets

Ten breeding sows were left in direct contact with their newborn piglets that had been experimentally infected with transmissible gastroenteritis (TGE) virus. All sows became infected with the virus. The sows developed fever and showed mild clinical signs of the disease for a few days. The sows excreted virus in the nasal secretion, feces, and milk during the acute febrile phase of illness. Virus was isolated from the nasal secretion of one sow as early as 20 hours after contact exposure to the infected piglets. At necropsy, the virus was more frequently isolated from the tissues of the upper respiratory tract than from small intestines; this finding indicated that the TGE coronavirus replicated in the upper respiratory tract and induced an acute respiratory infection in susceptible adult swine. Neutralizing antibody was present in the sera 8 sows after 12 to 36 days during the convalescent period. From these results, we conclude that susceptible sows in direct contact with ill piglets can become infected and by excreting virus can serve as a source of TGE virus for other susceptible pigs on the premises.

Physiologic studies of experimentally grain-engorged cattle and sheep

Seven sheep weighing 34 to 41 kg, each, 3 steers and 1 heifer weighing 230 to 460 kg each, were experimentally, "overfed" (induced grain engorgement). The most significant changes occurred in ruminal ingesta pH, blood pH, packed cell volume (PCV), hemoglobin (Hb), carbon dioxide pressure (PCO2, total CO2 (volume %), blood D-lactic acid, blood HCO3, and base excess. There was no common denominator that was especially pathognomonic.

Changes in motility and ph in the digestive tract of experimentally overfed sheep

Motility of the digestive tract of 4 sheep was studied with radiotelemetric equipment. After base line records were made, each sheep was overfed with 70 g of grain per kilogram of body weight. The ruminoreticulum did not become static until the ingesta pH was less than 5. The cecum had the same patterns of motility and pH as did the ruminoreticulum, but these returned to normal more quickly in surviving sheep. The motility patterns of the abomasum and the small intestine were more erratic. Results indicated that considerable quantities of grain (substrate for microbial growth) reached the cecum before ruminoreticular motility was inhibited.

Self-sterilizing inoculating loop

A self-sterilizing inoculating loop consisting of a step-down transformer and an adjustable timing circuit are described.