X-Linked mental retardation with fragile X. a pedigree showing transmission by apparently unaffected males and partial expression in female carriers

Summary A large family is reported in which mental retardation associated with the fragile site at Xq28 was found. Three normal males seemed to have transmitted the trait through their daughters to affected grandchildren.A total of 19 family members were investigated cytogenetically. Mentally retarded males showed macroorchidism and the fragile X. Three mentally retarded females were found, with the fragile X in a high percentage of cells; in contrast, the obligate carriers showed no or only few cells with the fragile X.     

Comparative analysis of autosomes in karyotypes from pig and rabbit using RBG-banding and in situ hybridization

The chromosomal location of the porcine gene for glucose phosphate isomerase (GPI) was previously mapped to 6p 12----6q21 in the pig karyotype. The replication patterns and morphology of this chromosome are very similar to those of chromosome 14 in the rabbit karyotype. With combined in situ hybridization and RBG-band induction it was demonstrated that the porcine GPI-probe hybridized most frequently to 14p11----14q12 in the rabbit karyotype, indicating a close relationship between morphology, replication pattern and gene location.     

A nondestructive method for peptide bond conjugation of antigenic haptens to a diphtheria toxoid carrier, exemplified by two antisera specific to acetolactate synthase.

A method for the preparation of an activated protein carrier is described: Protein carboxyl groups are transformed into N-hydroxysulfosuccinimide esters, a structure that will react with primary amino groups under amide bond formation. Although the activated ester is unstable under aqueous conditions, a significant amount of hapten molecules can be bound covalently to the carrier under very mild conditions. Ligands can be peptides or other molecules possessing a primary amino group. The method avoids the risk of ligand polymerization and no derivatization of the ligand prior to conjugation is needed. Residual unreacted ligand molecules can therefore be recovered in their native form by size exclusion chromatography. The method was used to conjugate two synthetic sugar beet acetolactate synthetase (E.C. 4.1.3.18) peptides to diphtheria toxoid. Antibodies were raised against both of the conjugates. The specificity of these antibodies against sugar beet acetolactate synthetase was verified using immunoblotting, ELISA, and immunoprecipitation.     

Determination of the three-dimensional solution structure of barnase using nuclear magnetic resonance spectroscopy

The solution conformation of the ribonuclease barnase has been determined by using 1H nuclear magnetic resonance (NMR) spectroscopy. The 20 structures were calculated by using 853 interproton distance restraints obtained from analyses of two-dimensional nuclear Overhauser spectra, 72 phi and 53 chi 1 torsion angle restraints, and 17 hydrogen-bond distance restraints. The calculated structures contain two alpha-helices (residues 6-18 and 26-34) and a five-stranded antiparallel beta-sheet (residues 50-55, 70-75, 85-91, 94-101, and 105-108). The core of the protein is formed by the packing of one of the alpha-helices (residues 6-18) onto the beta-sheet. The average RMS deviation between the calculated structures and the mean structure is 1.11 A for the backbone atoms and 1.75 A for all atoms. The protein is least well-defined in the N-terminal region and in three large loops. When these regions are excluded, the average RMS deviation between the calculated structures and the mean structure for residues 5-34, 50-56, 71-76, 85-109 is 0.62 A for the backbone atoms and 1.0 A for all atoms. The NMR-derived structure has been compared with the crystal structure of barnase [Mauguen et al. (1982) Nature (London) 297, 162-164].     

The membrane fraction of homogenized rat kidney contains an enzyme that releases epidermal growth factor from the kidney membranes

High levels of epidermal growth factor (EGF) are excreted in the urine and high levels of mRNA for the EGF-precursor have been demonstrated in the kidney. The EGF-precursor is a membrane bound peptide in the kidney, but little is known about the renal processing of the precursor. The present study shows that the membrane fraction of homogenized rat kidney contains an enzyme that releases immuno and receptor reactive EGF from the kidney membranes when incubated at 37 degrees C. Gel filtration shows that the EGF reactivity released from the membranes is similar to the EGF reactivity in rat urine. The EGF releasing enzyme is inhibited by the serine proteinase inhibitor aprotinin and by low temperatures (4 degrees C). The pH optimum of the reaction is pH 7.5-8.0.     

A model for population regulation with density- and frequency-dependent selection

The life-cycle of a species with separate generations is divided into a reproduction phase and a growing-up phase. In the reproduction phase we assume random mating and selection due to genotype differences in fecundity of the parents and viability of the offspring. During the growing-up phase we assume a (deterministic) death process in continuous time with death rates for the genotypes which increase linearly with the genotype population sizes.In the absence of genotype differences the model gives logistic population regulation. With genotype differences the model generalizes the usual separate generations selection patterns. In addition to these we exhibit cases with three polymorphic equilibria or with a stable cycle.     

SDS removal from protein by polystyrene beads

The applications of sodium dodecyl sulfate (SDS) to molecular weight determination (1,2) and for the separation of protein subunits (3) have been of immense value in biochemical studies [see Waehneldt (4) for a general review]. The tight stoichiometric binding of SDS to polypeptide chains has proven to be a nuisance if one desires to recover the activity of the isolated polypeptides. Removal of the SDS has been affected by the use of anion exchangers in the presence (5,6) and absence of urea (6). However, the residual levels of SDS or urea are often quite unsatisfactory for further protein studies.We have attempted to adapt the procedure of Holloway for the removal of Triton X-100 by Bio-Beads to the removal of SDS. We chose bovine serum albumin as a test protein since it has well-established strong binding properties for linear-chain fatty acids (7).     

Image processing and pattern recognition algorithms for evaluation of crossed immunoelectrophoretic patterns (crossed radioimmunoelectrophoresis analysis manager; CREAM)

A computerized method for automatic evaluation and comparison of crossed immunoelectrophoretic and crossed radioimmunoelectrophoretic patterns that requires limited hardware resources has been developed. For the initial reading of the plates an ordinary video camera is used. Feature extractors that allow the computer to recognize a point on the precipitation curve as being a peak point have been developed. After this automatic procedure the program allows for an interactive menu-driven proofreading phase during which it is possible to force the system to take into consideration any number of extra points along the precipitation curve in the curve-fitting process. The system has been tested on crossed immunoelectrophoretic patterns as well as crossed radioimmunoelectrophoretic patterns and it has been shown that the system can recognize the same precipitation curves on different immunoplates and autoradiographs. In addition, the system reports the mean, the variance, and the area of the precipitation curves, thus allowing not only a qualitative comparison of two or more plates but also a quantitation of individual antigens or antibodies.     

Identification of Trichoderma strains from building materials by ITS1 ribotyping, UP-PCR fingerprinting and UP-PCR cross hybridization

To study the role of Trichoderma in sick building syndrome, it is essential to be able to accurately identify species. Forty-four strains of Trichoderma spp. isolated from Danish buildings damaged by water leaks were identified using ITS1 ribotyping and universally primed PCR, UP-PCR. Ribotyping allowed the assignment of the strains into three distinct groups. High similarity of UP-PCR banding profiles of the strains allowed species designation for almost all strains (43 out of 44) when compared with the UP-PCR banding profiles obtained from reference strains of T. atroviride, T. citrinoviride, T. harzianum, T. longibrachiatum and T. viride. However, cross hybridization of UP-PCR products showed that the latter strain had high DNA homology to the ex-type strain of T. hamatum. The combined approach is a convenient way for reliable identification of Trichoderma strains.