Distribution of SchistoFLRFamide-like immunoreactivity in the adult ventral nervous system of the locust,Schistocerca gregaria

SchistoFLRFamide (PDVDHVFLRF-NH₂) is one of the major endogenous neuropeptides of the FMRF-amide family found in the nervous system of the locust,Schistocerca gregaria. To gain insights into the potential physiological roles of this neuropeptide we have examined the distribution of SchistoFLRFamide-like immunoreactivity in the ventral nervous system of adult locusts by use of a newly developed N-terminally specific antibody. SchistoFLRFamide-like immunoreactivity in the ventral nerve cord is found in a subgroup of the neurones that are immunoreactive to an antiserum raised against bovine pancreatic polypeptide (BPP). In the suboesophageal ganglion three groups of cells stain, including one pair of large posterior ventral cells. These cells are the same size, in the same location in the ganglion and have the same branching pattern as a pair of BPP immunoreactive cells known to innervate the heart and retrocerebral glandular complex of the locust. In the thoracic and abdominal ganglia two and three sets of cells, respectively, stain with both the SchistoFLRFamide and BPP antisera. In the abdominal ganglia the immunoreactive cells project via the median nerves to the intensely immunoreactive neurohaemal organs.     

Identification and chromosomal mapping of a third mouse runt-like locus

The Drosophila runt gene, which controls early events in embryogenesis, has been shown to have homologues in human and mouse. The human gene on 21q22 is involved in the t(8;21) associated with acute myeloid leukemia. Two mouse runt-like loci encoding DNA-binding proteins have been identified. We report here the isolation and partial sequence of a molecular clone of a third mouse runt-like locus. By using a panel of somatic cell hybrids and interspecific backcross mice, we map the novel locus to the telomeric region of mouse chromosome 4.     

Mutant HLA-A2 antigens as restricting elements for virus-specific cytotoxic T cells

Mutants of the EB virus-transformed cell line T5-1 (HLA-Al, 2; B8, 27), bearing well-characterized alterations in HLA-A2 antigen expression and unable to bind the HLA-A2-specific monoclonal antibody 13137.2, have been tested for their susceptibility to EB virus-specific cytolysis using effector T-cell preparations functionally restricted through relevant HLA antigens. Initial experiments first confirmed that the parent line T5-1 was susceptible to cytolysis by both common A2-restricted and 1327-restricted effector cells. While those T5-1 mutants with little or no surface A2 expression were not lysed by A2-restricted effectors, those targets with quantitatively normal expression of mutant A2 molecules were as susceptible to A2-restricted lysis as the parent line itself. In contrast, all the T5-1 mutant lines were susceptible to B27-restricted cytolysis. The results demonstrate that experimentally induced mutations of HLA-A2 antigen structure, affecting a serologically defined site on the molecule, can occur without altering that same molecule's expression of the T cell-restricting determinant(s). Such experimentally induced mutations are quite different from the naturally occurring variant A2 antigens which are present within the serologically defined A2 antigen group and which show changes at the T cell-restricting site.     

Selection of cell lines resistant to anti-transferrin receptor antibody: evidence for a mutation in transferrin receptor.

Some anti-murine transferrin receptor monoclonal antibodies block iron uptake in mouse cell lines and inhibit cell growth. We report here the selection and characterization of mutant murine lymphoma cell lines which escape this growth inhibition by anti-transferrin receptor antibody. Growth assays and immunoprecipitation of transferrin receptor in hybrids between independently derived mutants or between mutants and antibody-susceptible parental cell lines indicate that all of the selected lines have a similar genetic alteration that is codominantly expressed in hybrids. Anti-transferrin receptor antibodies and transferrin itself still bind to the mutant lines with saturating levels and Kd values very similar to those of the parental lines. However, reciprocal clearing experiments by immunoprecipitation and reciprocal blocking of binding to the cell surface with two anti-transferrin receptor antibodies indicate that the mutant lines have altered a fraction of their transferrin receptors such that the growth-inhibiting antibody no longer binds, whereas another portion of their transferrin receptors is similar to those of the parental lines and binds both antibodies. These results argue that the antibody-selected mutant cell lines are heterozygous in transferrin receptor expression, probably with a mutation in one of the transferrin receptor structural genes.     

Changes in cell-wall polysaccharides in relation to seedling development and the mobilisation of reserves in the cotyledons of Lupinus angustifolius cv. Unicrop

Some 22% of the dry weight of the cotyledons of resting seeds of Lupinus angustifolius cv. Unicrop has been shown to be non-starch polysaccharide material comprising the massively thickened walls of the storage mesophyll cells. On hydrolysis this material released galactose (76%), arabinose (13%), xylose (4%), uronic acid (7%): only traces of glucose were detected indicating the virtual absence of cellulose from the walls. Changes in the amount and composition of this material following germination have been studied in relation to parameters of seedling development and the mobilisation of protein, lipid and oligosaccharide reserves. Starch, which was not present in the resting seed, appeared transitorily following germination: under conditions of continuous darkness starch levels were reduced. During the period of bulk-reserve mobilisation, 92% of the non-starch polysaccharide material disappeared from the cotyledons. The residual cell-wall material released galactose (14%), arabinose (19%), xylose (24%) and uronic acid (43%). The galactose and arabinose residues of the cotyledonary cell walls clearly constitute a major storage material, quantitatively as important as protein. The overall role of the wall polysaccharides in seedling development is discussed.     

The nucleoside sequence of tyrosine tRNA from Bacillus stearothermophilus.

The nucleotide sequence of tRNATyr from B. stearothermophilus has been determined: pG-G-A-G-G-G-G-s4U-A-G-C-G-A-A-G-U-Gm-G-C-U-A-A-m1A-C-G-C-G-G-C-G-G-A-C-U-Q-U-A-ms2i6A-A-psi-C-C-G-C-U-C-C-C-U-U-U-G-G-G-U-U-C-G-G-C-G-G-T-psi-C-G-A-A-U-C-C-G-U-C-C-C-C-C-U-C-C-A-C-C-AOH. A combination of classical fingerprinting methods, partial nuclease P1 digestion and two-dimensional homochromatography and a rapid "read off" sequencing gel technique were used to establish the complete nucleotide sequence.     

Sublethal stress in Escherichia coli: a function of salinity.

Sublethal stress in Escherichia coli was detected in various test media after exposure (in vitro) to seawater of various salinites. Stress was measured with an electrochemical detection technique and a beta-galactosidase assay. Test media included EC medium, medium A-1, and tryptic soy broth modified to contain lactose for beta-galactosidase assay experiments. Stress was defined as the difference between a predicted electrochemical response time calculated for unstarved cells from a standard curve and the observed electrochemical response time for cells starved in seawater. The higher the salinity, the greater the stress for all test media examined. Stress was most pronounced in EC and was attributed primarily to initial die-off of starved cells exposed to the test medium at the elevated temperature of 44.5 degrees C. Lag time and growth rates in test media were not significantly affected by salinity. beta-Galactosidase specific activity, assayed in starved cells after transfer to an induction medium at 44.5 degrees C for 150 min, was inversely related to the salinity of the starved cell suspension. The consequences of these observations with respect to coliform enumeration methods are discussed.     

Reproductive studies of Brahman cattle V. The effect of various dose levels of estradiol-17β upon serum luteinizing hormone in ovariectomized Brahman cows

Twelve mature chronically-ovariectomized Brahman cows were randomly assigned to receive three of six different dosages of estradiol-17_b (E2) at three different time periods such that at the termination of the trial six animals received each E2 dosage. The E2 was suspended in 0, 1, 2.5, 5, 10 and 20 milligrams. A two week period was maintained between injections. The cows were bled via coccygeal vessel puncture immediately before E2 injection, every 2 hr from 0 to 18 hr, every hr from 18 to 42 hr and every 2 hr from 42 to 48 hr postinjection. Blood was processed to yield serum and stored at ?20 Celsius. Serum luteinizing hormone (LH) was quantitated by validated radioimmunoassay. An LH surge was defined as a sustained elevation of LH at least two standard deviations above the level of LH prior to the rise and was observed in $\text{0}\text{6}$, $\text{3}\text{6}$, $\text{5}\text{6}$, $\text{5}\text{6}$, $\text{5}\text{6}$, and $\text{6}\text{6}$ cows administered 0, 1, 2.5, 5, 10, and 20 mg of E2, respectively. All animals injected with E2 responded with a significant initial decrease (independent of E2 dosage) in LH that persisted from 2 through 12 hr post E2 injection. No significant decrease in LH levels was recorded in animals injected with the corn oil vehicle. The time to the LH surge differed (P<.05) between 1 mg E2 (10 hr) vs 20 mg E2 (19.5 hr), 1 mg E2 vs 10 mg E2 (16.2 hr), and 2.5 mg E2 (12.4 hr) vs 20 mg estradiol-17_β. Luteinizing hormone concentrations at the onset of the surge did not differ (P>.10) between E2 dosages. The elapsed time from E2 injection to the peak LH value differed (P<.05) between 1 mg E2 (20.3 hr) vs 20 mg E2 (26.8 hr), and 2.5 mg E2 (21.2 hr) vs 20 mg estradiol-17_β. The peak LH value, the area under the LH curve and the duration of the LH surge did not differ (P>.10) with E2 dosage. The time to the end of the LH surge differed (P<.05) between 1 mg E2 (25.3 hr) vs 2.5 mg E2 (31.6 hr), 1 mg E2 vs 5 mg (34.4 hr), 1 mg E2 vs 10 mg E2 (34.8 hr), 1 mg E2 vs 20 mg E2 (37.3 hr), and 2.5 mg E2 vs 20 mg estradiol-17_β. Luteinizing hormone values at the termination of the surge did not differ (P>.10) between dosages nor did the LH values at the termination of the surge differ (P>.10) from LH concentrations observed at the onset of the LH surge.     

Effect of variable suckling intensity and estrogen administration upon serum luteinizing hormone in Brahman cows

Ten mature Brahman cows were randomly allotted within calving intervals to either a suckled (S) or nonsuckled (NS) treatment group. All cows received a 20 mg intramuscular injection of estradiol-17beta (E2), suspended in 2 ml of corn oil, to determine the effect of suckling on the estrogen induced LH surge. Starting on day 21 postpartum the S cows were suckled at six hour intervals for 24 hours, at which time they were challenged with a 20 mg E2 injection. The suckling regimen was continued for 48 hours postinjection. The NS cows were separated from their calves on day 21 postpartum and received no suckling stimulus for 72 hours. At 24 hours after calf separation, the NS cows were challenged with a 20 mg E2 injection. Blood samples were removed at two hour intervals beginning 10 hours post E2 injection until 36 hours postinjection, at which time blood samples were removed at four hour intervals until 48 hours postinjection. Blood samples were processed to yield serum and assayed for luteinizing hormone (LH) via radioimmunoassay. The injection of a 20 mg dose of E2 induced an LH surge in all cows. The NS cows were found to exhibit a longer (P<.05) duration of the estrogen induced LH surge than the S cows, 15.6 +/- .98 and 12.4 +/- .75 hours, respectively. The timing parameters (time to start of LH surge, time to peak LH value and time to end of surge) and LH concentration parameters (LH concentration at start of LH surge, peak value of LH surge and LH concentration at end of LH surge) were not different between suckling regimens. No blockage of the LH response to estrogen challenge was found on day 22 postpartum. Suckling did depress the duration of the LH surge indicating some blockage due to suckling stimuli.