Behavioral phenodeviance: A Lerneresque conjecture

Developmental instability, detectable in morphological and meristic characters, is typically associated with reduced fitness. The actual mechanism by which fitness is reduced in these cases is difficult to identify. We propose that developmental instability also manifests itself at the behavioral level and that when this occurs, behavioral phenodeviance is the result. According to this model, abnormal or phenodeviant behavior compromises fitness. Examples are provided fromDrosophila and man.     

Heart Rate and Systolic Blood Pressure Variability in the Time Domain in Patients with Recent and Long-Standing Diabetes Mellitus

Diabetes Mellitus (DM) affects the cardiovascular response of patients. To study this effect, interbeat intervals (IBI) and beat-to-beat systolic blood pressure (SBP) variability of patients during supine, standing and controlled breathing tests were analyzed in the time domain. Simultaneous noninvasive measurements of IBI and SBP for 30 recently diagnosed and 15 long-standing DM patients were compared with the results for 30 rigorously screened healthy subjects (control). A statistically significant distinction between control and diabetic subjects was provided by the standard deviation and the higher moments of the distributions (skewness, and kurtosis) with respect to the median. To compare IBI and SBP for different populations, we define a parameter, α, that combines the variability of the heart rate and the blood pressure, as the ratio of the radius of the moments for IBI and the same radius for SBP. As diabetes evolves, α decreases, standard deviation of the IBI detrended signal diminishes (heart rate signal becomes more “rigid”), skewness with respect to the median approaches zero (signal fluctuations gain symmetry), and kurtosis increases (fluctuations concentrate around the median). Diabetes produces not only a rigid heart rate, but also increases symmetry and has leptokurtic distributions. SBP time series exhibit the most variable behavior for recently diagnosed DM with platykurtic distributions. Under controlled breathing, SBP has symmetric distributions for DM patients, while control subjects have non-zero skewness. This may be due to a progressive decrease of parasympathetic and sympathetic activity to the heart and blood vessels as diabetes evolves.     

In vitro metabolism of [2-13C]-ethanol by 1H NMR spectroscopy using 13C decoupling with the reverse dept polarization-transfer pulse sequence

The metabolism of [2-13C]-ethanol by alcohol dehydrogenase purified from Drosophila melanogaster has been observed by proton nuclear magnetic resonance spectroscopy (NMR). The reverse-DEPT pulse sequence, with composite pulse 13C decoupling to simplify and increase the signal-to-noise of spectra, has been used to eliminate the strong water signal while still observing the proton signals of metabolites of interest. Using these techniques the rates of synthesis of acetaldehyde, its diol and acetate from [2-13C] ethanol by alcohol dehydrogenase were measured simultaneously.     

Interaction of the unique N-terminal region of tyrosine kinase p56lck with cytoplasmic domains of CD4 and CD8 is mediated by cysteine motifs

p56lck, a lymphocyte-specific member of the src family of cytoplasmic protein-tyrosine kinases, is associated noncovalently with the cell surface glycoproteins CD4 and CD8, which are expressed on functionally distinct subpopulations of T cells. Using transient coexpression of p56lck with CD4 or CD8 alpha in COS-7 cells, we show that the unique N-terminal region of p56lck binds to the membrane-proximal 10 and 28 cytoplasmic residues of CD8 alpha and CD4, respectively. Two cysteine residues in each of the critical sequences in CD4, CD8 alpha, and p56lck are required for association. Our results suggest a novel role for cysteine-mediated interactions between unrelated proteins and provide a model for the association of other src-like cytoplasmic kinases with transmembrane proteins.     

Sequence and characterization of twoHSP70 genes in the colonial protochordateBotryllus schlosseri

Two genes belonging to the heat shock protein 70 gene family have been cloned from the colonial protochordateBotryllus schlosseri. The two intronless genes(HSP70.1 andHSP70.2) exhibit 93.6% sequence identity within the predicted coding region, and 83.3% and 81.7% sequence identity in the 5′ and 3′ flanking regions, respectively. The predicted amino acid sequences are 95% identical and contain several signatures characteristic of cytoplasmic eukaryoticHSP70 genes (Gupta et al. 1994; Rensing and Maier 1994). Northern blotting and sequence analysis suggest that both genes are heat-inducible merebees of theHSP70 gene family. Given these characteristics,HSP70.1 andHSP70.2 appear to be good candidates for protochordate homologues of the major histocompatibility complex-linkedHSP70 genes of human, mouse, and rat (Milner and Campbell 1990; Walter et al. 1994). Further experiments to determine whether there is functional evidence for such similarity are in progress. The nucleotide sequence data reported in this paper have been submitted to the EMBL/GenBank nucleotide sequence databases and have been assigned the accession numbers US 1901 (HSP70.1) and US 1902 (HSP70.2)     

Sucrose supply can increase longevity of broccoli (Brassica oleracea) branchlets kept at 22°C

Sucrose was supplied several hours after harvest to broccoli branchlets via the transpiration stream in order to increase the amount of sucrose available for respiration and to determine its influence on longevity at 22°C. Calculations based on solution uptake indicated that an 8% (w/v) sucrose solution supplied sufficient substrate for respiration, but the pattern of respiratory decline after harvest was not altered by supply of exogenous sucrose, and yellowing of floret sepals began after 2 days. However, when sucrose was supplied immediately after harvest, yellowing was delayed. Treatment with cytokinin (50 ppm 6-benzylaminopurine), to delay yellowing, had no effect on levels of sucrose in branchlets after 4.5 days, but retarded loss of chlorophyll. Floret tissues appear to sense the decline in sucrose after harvest, the result being induction of senescence as judged by yellowing. 6-benzylaminopurine may block the sensing mechanism.Abbreviations BAP 6-benzylaminopurine     

Recent Developments in Human Behavioral Genetics: Past Accomplishments and Future Directions

The field of behavioral genetics has enormous potential to uncover both genetic and environmental influences on normal and deviant behavior. Behavioral-genetic methods are based on a solid foundation of theories and methods that successfully have delineated components of complex traits in plants and animals. New resources are now available to dissect the genetic component of these complex traits. As specific genes are identified, we can begin to explore how these interact with environmental factors in development. How we interpret such findings, how we ask new questions, how we celebrate the knowledge, and how we use or misuse this knowledge are all important considerations. These issues are pervasive in all areas of human research, and they are especially salient in human behavioral genetics.     

Differential Localization of Glutathione-S-Transferase Yp and Yb Subunits in Oligodendrocytes and Astrocytes of Rat Brain

Glutathione-S-transferase Yb subunits were recently identified in rat brain and localized to astrocytes, ependymal cells lining the ventricles, subventricular zone cells, and tanycytes. Another isoform, Yp (pi family), was detected in rat brain by immunoblotting, and its mRNA was detected by Northern hybridizations. Double immunofluorescence localized Yb and Yp in different glial cells. The strongly Yp-positive cells were identified as oligodendrocytes by virtue of their arrangement in rows in white-matter tracts, colocalization in strongly carbonic anhydrase-positive cells, and association with myelinated tracts in the corpus striatum. Ependymal cells in the choroid plexus and ventricular lining were also strongly Yp positive, whereas Yb was not detected in the choroid plexus. The occurrence of Yp at low levels in astrocytes was indicated after immunostaining by a sensitive peroxidase-antiperoxidase method, which revealed weak staining of those cells in the molecular layer of the cortex. The data suggest that Yb and Yp subunits are primarily localized to astrocytes and oligodendrocytes, respectively, and that both are absent from neurons. The glutathione-S-transferase in oligodendrocytes may participate in the removal of toxins from the vicinity of the myelin sheath. The finding of glutathione-S-transferases in ependymal cells and astrocytes in the brain also suggests that this enzyme could be a first line of defense against toxic substances.