Growth of ectomycorrhizal fungi stimulated by lipids from a pine root exudate

Summary The content of fatty acids was analysed in an exudate from roots of pine seedlings grown axenically in vermiculite with a synthetic nutrient medium. The dominating fatty acdis were fewer in the exudate than in the roots. Unsaturated fatty acids were predominant. The total lipid fraction of the exudate promoted mycelial growth in two of the three ectomycorrhizal fungi tested.     

Differential permeabilization of membranes by saponin treatment of isolated rat hepatocytes. Release of secretory proteins.

Monolayer cultures of rat hepatocytes were treated with increasing concentrations of saponin (prepared from Gypsophila plants) for 30 min at 6 degrees C. Differential permeabilization of the intracellular membranes could be demonstrated: at 0.040 mg of saponin/ml the plasma membrane was permeabilized, as assessed by the release of 50% of the total cellular amount of lactate dehydrogenase, and at 0.20 mg/ml the endoplasmic reticulum was permeabilized, as measured by the release of 50% of pulse-35S-labelled albumin. The Golgi complex was permeabilized at an intermediate saponin concentration, as indicated by the release of homogeneously 35S-labelled albumin; about half the intracellular albumin is located in this organelle. At 1.0 up to 5.0 mg of saponin/ml 90-95% of the radioactively labelled albumin was released. Even at 5.0 mg/ml less than 10% of the membrane of the endoplasmic reticulum was solubilized, as judged by the degree of release of a membrane-bound enzyme specific for this organelle. These results demonstrate the usefulness of saponin as a tool for investigating the interior of different intracellular compartments.     

The loci for parathyroid hormone and beta-globin are closely linked and map to chromosome 15 in cattle

We report linkage of the loci for beta-globin (HBB) and parathyroid hormone (PTH) in cattle and the assignment of both loci to the bovine chromosome region 15q13-q23. Linkage was analyzed in a family of paternal half-sibs by the use of restriction fragment length polymorphisms detected with bovine probes derived from the HBB and PTH genes. The HBB polymorphism was detected by digestion with restriction endonuclease HindIII and the PTH polymorphism with MspI. The maximum lod score for linkage of PTH with HBB was zeta = 4.52 at theta = 0, suggesting very close linkage of the two loci. The finding of the PTH/HBB linkage is corroborated by the physical assignment of both loci to the region 15q13-q23 by in situ hybridization with bovine genomic probes derived from PTH and HBB, respectively. Since HBB and PTH are syntenic in man and mouse, these results in cattle represent another example of conservation of synteny in the evolution of mammalian chromosomes.     

Comparison of diagnostic methods for detection of low infestation levels ofVarroa jacobsoni in honey-bee (Apis mellifera) colonies

Thirty-five honey-bee colonies, originally free fromVarroa jacobsoni (Oudemans) were monitored approximately every third week for the presence of the mite during 16 months following an initial introduction of five to eight adultVarroa females in early July. Investigations of hive debris detected the presence ofV. jacobsoni in 22 colonies (63%) within three months of the mite introduction. During the first winter period (October–April), mites were found in the hive debris of 13 colonies (37%). In terms of detectingVarroa during the summer in colonies with sealed brood, investigations of hive debris were more effective than sampling of brood. Brood sampling was more effective than sampling of live bees. In colonies without sealed brood, investigations of hive debris or of live bee samples seemed approximately equally efficient. The highest correlation between sampling methods was found between daily mite downfall and mites per live bee (r=0.81) in colonies with sealed brood. During the winter, investigations of dead bees and hive debris were approximately equally efficient in detectingVarroa.     

Role of serum and urinary Tamm-Horsfall protein in the surveillance of kidney transplants

The study of 24-h urinary excretion proves to be quite interesting from a theoretical point of view on account of its topographic origin in the nephron and from a practical point of view to control renal transplant patients with favourable or unfavourable course. In both cases, the results we obtain are in accordance with that of blood creatinine assay and ratio N-acetyl-beta-D-glucosaminidase (NAG)/creatinine in urine. The prolonged study of serum THG concentration confirms the previous data regarding the outcome of renal grafts. Moreover, particularly low concentration rates probably imply the interference of factors such as: renal toxins or anti-THG autoantibodies.     

Assignment of the porcine major histocompatibility complex to chromosome 7 by in situ hybridization

The major histocompatibility complex (SLA) of the domestic pig (Sus scrofa) was regionally mapped to 7p12----q12 by in situ hybridization with an SLA class I-specific recombinant DNA probe. This localization contradicts linkage data suggesting a possible assignment of the SLA locus to porcine chromosome 15.     

Lymphocyte ecto-5'-nucleotidase activity in infancy: increasing activity in peripheral blood B cells precedes their ability to synthesize IgG in vitro

Ecto-5'-nucleotidase activity was measured in peripheral blood lymphocytes isolated from serial specimens from nine healthy full-term infants and two premature infants at 0, 2, 4, and 6 mo of age. The postnatal nadir in activity was 7.1 +/- 2.0 nmol/hr/10(6) cells, which is the same as the activity in cord blood lymphocytes (7.0 +/- 2 nmol/hr/10(6) cells). The activity rose twofold to 13.2 +/- 3.8 nmol/hr/10(6) cells at 6 mo of age (p less than 0.001, paired t-test), which is similar to the activity in adult peripheral blood lymphocytes (14.1 +/- 6.3 nmol/hr/10(6) cells). This increased activity in total lymphocytes reflects increased activity in the B cell population. B cell ecto-5'-nucleotidase activity in two infants at 12 to 13 mo of age was 19.3 and 25.2 nmol/hr/10(6) cells, values that are four-to fivefold higher than for cord blood B cells (5.6 +/- 2.8 nmol/hr/10(6) cells) and within the normal range for adult B cells (27.9 +/- 12 nmol/hr/10(6) cells). In spite of a greatly expanded peripheral blood B cell population, studies of immunoglobulin biosynthesis in vitro demonstrated that infant peripheral blood B cells are functionally immature with no synthesis of IgG in response to Epstein Barr virus. Thus, the increase in peripheral blood B lymphocyte ecto-5'-nucleotidase activity in infants precedes their acquisition of a capacity for IgG synthesis in vitro. Data from a hypogammaglobulinemic infant revealed a persistently low ecto-5'-nucleotidase activity over a 10-mo period until at 14 mo of age the activity was 8.8 nmol/hr/10(6) cells in total lymphocytes and 13.0 nmol/hr/10(6) cells in B cells, which correlated with in vivo and in vitro evidence of delayed B cell maturation. Thus, ecto-5'-nucleotidase activity may be a useful cell surface marker in studies of human postnatal B cell maturation.