Ultrastructure of rat pituitary LH gonadotrophs in relation to serum and pituitary LH levels following repeated LH-RH stimulation

The effects of single and repeated LH-RH injections at 120 min intervals on female rat LH gonadotrophs and on pituitary and serum LH levels were investigated using electronmicroscopy and radioimmunoassay. A temporary stimulation of granule release, of protein and new granule synthesis and of the accumulation of lysosomal structures was found in LH cells after the first LH-RH injection. The temporary stimulations were massively enhanced after the second injection. These consecutive yet in their time-sequence overlapping processes account for the initial depletion of secretory granule content (3--15 min after LH-RH injection), for the subsequent regranulation and accumulation of granules above control levels (60--120 min after injection) and also for the reduction in the number of granules to control levels (150 min after LH-RH injection and thereafter). Increased polymorphic lysosomal structures are believed to be responsible for this reduction of excess granules. The amount of assayable pituitary and serum LH generally corresponds with the morphological changes observed in LH-gonadotrophs, thus further substantiating the above observations. A schema which summarizes the observed morphological and hormonal changes in their time-sequence in response to LH-RH stimulation depicts the short-term regulation of secretory processes in female gonadotrophs.     

The spermatozoon of Oikopleura dioica Fol (Larvacea,Tunicata)

Summary The spermatozoon of Oikopleura dioica is about 30 m long, with a spherical head, about 1 m wide, a 3 m long and 1 m wide midpiece, and a 25 m long tail with a tapered end piece. The head contains a nucleus with the chromatin volume limited to about 0.1 m³. A small acrosome is found in an anterior inpocketing, and a flagellar basal body in a posterior inpocketing of the nucleus. The midpiece contains a single mitochondrion with the flagellar axoneme embedded in a groove along its medial surface. The flagellar axoneme has the typical 9 + 2 substructure, and the basal body the typical 9+0 substructure. A second centriole and special anchoring fibres are absent.     

The H2 18O enrichment in the leaf water of tropic trees: Comparison of species from the tropical rain forest and the semi-arid region in Brazil

Summary The H₂ ¹⁸O enrichment,, in the water of leaves from four Brazilian trees, was studied. In all trees the leaf water showed a periodic variation in, with a maximum in the early afternoon and a minimum around 6 a.m. In general was found to be either higher or lower than the stationary enrichment which is supposed to depend only on the relative atmospheric humidity. This effect is due to the slow response of the system to variations of the humidity. For a special case, where steady-state conditions could be anticipated, the kinetic enrichment was obtained to 20 ± 3, which agrees with theoretical predictions.     

Distribution of myosin and the glial fibrillary acidic protein (GFA Protein) in rat spinal cord and in the human frontal cortex as revealed by immunofluorescence microscopy

Summary The glial fibrillary acidic (GFA) protein and myosin were localized in rat spinal cord and human frontal cortex using specific antibodies against GFA protein from human spinal cord and highly purified smooth myosin from chicken gizzard by means of an indirect immunofluorescence microscopical approach. A strong GFA protein and myosin immunoreactivity was found in astrocytes of the white and grey matter and in the external glial limitans membrane. The very fine branches of astrocytic processes stained with antiGFA protein, but not with anti-myosin. Similar results were obtained with the human frontal cortex, where myosin antibodies failed to reveal the very fine branches of protoplasmic astrocytes.As a whole, staining with the GFA protein antiserum was more crisp than with the myosin antibody.Thanks are due to Professor J.R. Wolff, Max-Planck Institute for Biophysical Chemistry, Göttingen, for stimulating discussions, to Ursula König, Christa Mahlmeister and Renate Steffens for skilful technical assistance, and to Heidi Waluk for the photographic workSupported by grants from Deutsche Forschungsgemeinschaft (Br 634/1, Dr 91/1, Un 34/4, Ste 105/19)Dedicated to Prof. Dr. med. H. Leonhardt on the occasion of his 60. birthday     

Desmosomes: Their occurrence between adjacent primary oocytes in polyovular follicles in the rabbit

Summary In polyovular, primordial follicles in the rabbit, desmosomes are found between apposing oocyte surfaces. Morphologically these desmosomes correspond closely to those described in epithelia of vertebrates. The desmosomes alternate with other junctions which are probably gap junctions.This work was supported in part by the G.R.S.T. Grant n 75.7.1313     

The paramedial neurosecretory cells of the suboesophageal ganglion of the cricket,Teleogryllus commodus (Walk.)

Summary Ovariectomy, performed immediately after the final hatch, caused a reduction of stainable (neurosecretory?) material in the paramedial neurosecretory cells (PNC) (A-type) of the suboesophageal ganglion in 10 day-old females of Teleogryllus commodus (Walk.). A concomitant increase in nuclear volume and in the incorporation of ³⁵S-cysteine indicates increased synthesis of neurosecretory material. From these findings it is concluded that more stainable material is secreted in the cerebral neurohaemal organ after Ovariectomy. A functional relationship between the PNC and the ovaries is suggested.     

Myxobacterial slime and proteolytic activity

An extracellular protein-polysaccharide-lipide (PPL) complex from exponentially growing cultures of Myxococcus virescens was purified by phosphate precipitation and gel chromatography. The high molecular weight slime polymer appeared homogenous upon isoelectric focusing. The PPL complex exhibited proteolytic activity against gelatin and the activity was only partly reduced by heat treatment. The function of the slime polymer as protein denatured was studied. The complex formed micelles similar to anionic detergents and it inhibited the precipitation and coagulation of proteins by trichloroacetic acid. Lysozyme was totally inactivated when treated with the PPL complex. By gel chromatography binding studies, the PPl complex was found to bind lysozyme in the ratio of 1 to 5.8 (w/w). After separation of added protein from the complex the anticoagulation effect on the protein remained. The biological function of the PPL complex was demonstrated with hemoglobin. When all susceptible peptide bonds in PPL-treated hemoglobin were hydrolyzed by trypsin only 20% in the urea-denatured protein were attacked. The combined role of slime and proteolytic activity is discussed.Abbreviations Used PPL protein-polysaccharide-lipide - TCA trichloroacetic acid - BSA bovine serum albumin - Tris tris-(hydroxymethyl)aminomethane - CMC critical micelle concentration - DNFB 2,4-dinitrofluorobenzene - DNP N-dinitrophenyl - SDS sodium dodecylsulphate - H.U. Hultin units     

Subcellular distribution of enzymes involved in α-glucan utilization in Klebsiella pneumoniae

The double-isotopic labelling technique was used to identify comprehensively proteins involved in α-glucan catabolism in Klebsiella pneumoniae NCTC 9633. Cells were grown with either glycerol in the presence of ³H-leucine or with glycerol plus maltose in the presence of ¹⁴C-leucine. Each labelled culture was then fractionated into the main subcellular components, i.e. the cytoplasm, periplasm, cytoplasmic and outer membrane. Corresponding fractions derived from ³H-labelled and ¹⁴C-labelled cells were combined, and the proteins were analyzed by polyacrylamide gel electrophoresis under denaturing conditions. Gel slices were then counted for ³H- and ¹⁴C-radioactivity, a positive deviation from the standard ¹⁴C/³H ratio being evidence for the presence of a protein specifically induced by maltose in the culture medium. The protein pattern thus obtained was compared with the properties of proteins comprising a similar pathway for maltodextrin utilization in Escherichia coli K-12. Ample information which has been obtained mainly by genetic analysis is available about maltodextrin-utilizing enzymes in E. coli K-12.

1. Cytoplasm. Neither amylomaltase nor maltodextrin phosphorylase, well-known soluble enzymes, were identifiable by the double-labelling technique, presumably because these enzymes constitute only a very minor portion of all soluble proteins in the cytoplasm.
2. Periplasm. A prominent protein with a mass of 43000 daltons (43 kD) was found similar to the maltose-binding protein of E. coli K-12 (44 kD).
3. Cytoplasmic membrane. At least 2 proteins with a mass between 40 and 50 kD were detected, minor proteins were seen at ≈ 15 and ≈ 20 kD. One or 2 of the proteins may function as a permease catalyzing the active transport of maltodextrins.
4. Outer membrane. The major protein had a mass of 55 kD, other proteins were found with ≈ 18, ≈48, and ≈140 kD. The major protein may have the same function as the maltodextrin pore protein in E. coli K-12 (55 kD), because K. pneumoniae could grow on 10 μM maltose at practically the same rate as on 10 mM maltose. The 140 kD protein is pullulanase.

     

Effects of isoniazid (INH) on the oogenesis of mice

Summary Mutagenic damages in female germ, cells of mice have been tested with the dominant, lethal assay and the cytogenetic analysis of unfertilized M II-oocytes. Concluding one can say that from the experimental data presented here do not show any mutagenic effect of INH on oogenesis of different strains of mice can be stated.