Immunohistochemistry of tonin in rat submandibular gland during development, lactation and secretion

Tonin is a serine protease found in high concentrations in the submandibular gland (SMG) of the adult rat where it has been localized by immunohistochemistry in the granular ducts. The present study examined the development of tonin in the SMG, the effect of lactation and of stimulation of tonin release, using the peroxidase-antiperoxidase technique and antitonin. Tonin-like immunoreactivity first appeared in the primitive striated duct of the SMG on day 19 foetal and increased in intensity as the ducts developed into granular ducts. Reaction product in granules was seen on day 17 postpartum. Its localization within granules was established by immunochemistry of Sepharose beads to which had been coupled the contents of granules isolated from adult rats. The granular ducts of female rats, which are less developed than in the male, showed a marked increase in tonin-immunoreactivity during lactation. Stimulation of tonin secretion by isoprenaline caused massive discharge of tonin-like immunoreactivity into the lumen of the granular ducts during in vitro incubation. However, within one hour complete regranulation was apparent. The secretion was prevented by propranolol. The results indicate that tonin or a tonin-like substance appears in the rat submandibular gland late in gestation in ducts that presumably develop into granular ducts where it is found in abundance in granules in the adult, that the amount in females is increased during lactation, and that most of the granules are discharged during stimulation, only to be rapidly replaced.     

Vasopressin-immunoreactive cells in the dorsomedial hypothalamic region,medial amygdaloid nucleus and locus coeruleus of the rat

Summary Recently, the existence of a vasopressin-immunoreactive cell group was described in the bed nucleus of the stria terminalis (van Leeuwen and Caffé 1983). In the present investigation additional nuclei containing vasopressin-immunoreactive cells were found, after colchicine pretreatment, in the dorsomedial hypothalamus, medial amygdaloid nucleus and the locus coeruleus.Vasopressin-immunoreactive cells in the dorsomedial hypothalamus and medial amygdaloid nucleus are small (8–14 m and 10–14 m, respectively), while those in the locus coeruleus are medium-sized (20–25 m). Incubation with anti-bovine neurophysin II and anti-rat neurophysin revealed staining of the same cell group in the above-mentioned areas. None of these cell groups show stained cells after incubation with anti-oxytocin and anti-bovine neurophysin I. When sections of the homozygous Brattleboro rat, which shows a deficiency in vasopressin synthesis, are incubated with anti-vasopressin, anti-bovine neurophysin II, or anti-rat neurophysin, no immunoreactivity can be observed in these brain regions.The above-mentioned cell groups may contribute to the vasopressinergic innervation of brain sites that have been reported to persist after lesioning of the suprachiasmatic, paraventricular and bed nuclei of the stria terminalis.     

Ontogenetic development of the pineal organ,parapineal organ,and retina of the three-spined stickleback,Gasterosteus aculeatus L. (Teleostei)

The ontogenetic developments of the pineal organ, parapineal organ, and retina were studied by the use of light and electron microscopy in embryos and fry of the teleost, Gasterosteus aculeatus, from 60 to 168 h after fertilization. Sixty to 66 h after fertilization, the primordium of the pineal complex is discernible in the diencephalic roofplate; the parapineal anlage is located rostral to the pineal anlage. Photoreceptor cells endowed with outer segments are present in the embryonic pineal organ already after 72 h, whereas outer segments of retinal photoreceptors could not be demonstrated before 144 h (hatching occurs between 120-144 h). Furthermore, neuropil formations with synaptic specializations are present in the rostral part of the pineal organ 108 h after fertilization. At 72 h, the embryonic parapineal parenchyma is already differentiated into parapinealocytes, which give rise to the parapineal tract, and glia-resembling elements. Although parapinealocytes carry cilia (9 X 2 + 0), only a single outer segment of the photoreceptor type could be demonstrated in the parapineal organ of one adult stickleback. Photoreceptors present in the pineal organ of unhatched embryos are hardly involved in visual functions, but may already at this early developmental stage serve as photoneuroendocrine transducers.     

Cerebrospinal fluid-contacting neurons of the central canal and terminal ventricle in various vertebrates

Cell and Tissue Research - Cerebrospinal fluid (CSF)-contacting neurons were studied by means of electron microscopy in the spinal cord and/or terminal ventricle of the ray, Raja clavata...     

The human thyroglobulin gene contains two 15-17 kb introns near its 3''-end.

We have cloned overlapping segments of the human thyroglobulin gene from a genomic cosmid library. Restriction mapping and electron microscopy show that a region of 38 kb at or near the 3'-end of this gene encodes only 850 nucleotides or 10% of the messenger RNA (mRNA) sequence. The region contains five exons of 130-210 nucleotides, split by introns of 1 to 15-17 kb. This represents the lowest ratio of coding to non-coding DNA (2.2%) found thus far in any eukaryotic gene. Blot hybridization under non-stringent conditions shows the presence of only one copy of this gene in the human genome and the absence of other closely related sequences.     

A double helix B-type geometry based on high-resolution proton NMR of single-helical DNA fragments: d(TA)5 x d(TA)5.

A single-helical B-type geometry is presented based on 1H NMR observations on d(TATA) and several other small single-helical DNA fragments. The structure is extended to one complete turn of double-helical DNA and its characteristics are compared with other known B-type structures.     

Synthesis of short RNA fragments by the benzotriazolyl phosphotriester approach

Analytical and experimental evidence will be presented to show that addition of a slight excess of 2-chlorophenyl-0,0-bis[1-benzotriazolyl]phosphate to a properly 2',5'-protected ribonucleoside gives an intermediate 3'-phosphotriester, which, after addition of a 2'-protected ribonucleoside, affords a dimer containing solely a 3'-5'-internucleotide linkage. The above phosphorylation procedure has been used in the synthesis of the pentamer UpApCpGpC.     

Application of silver stains to gastric endocrine cells in plastic sections

Summary A simultaneous light and electron microscopic study of mouse gastric mucosa was made to determine whether the silver nitrate methenamine stain of Duk-Ho Lee could be used to stain gastric endocrine-like cells in plastic embedded tissue. Examination of consecutive thick and thin sections showed that this stain blackened the granules of the predominant type of endocrine-like cell present. Blackening of the granules with silver occured in tissue fixed in osmium tetroxide solution with or without dichromate salt or in tissue fixed in glutaraldehyde then treated with osmium. The intensity of staining was deepest in the osmium-dichromate fixed tissue, but the glutaraldehyde-osmium procedure gave less interference from diffuse silver impregnation and better preservation of detail for electron microscopy.     

The Mechanism of Microbiological Leaker Spoilage of Canned Foods: A Review

S ummary : This review summarizes the work on the subject carried out mainly in the authors'laboratories but also in the associated laboratories of Metal Box Co. Ltd., London, and Plat Manufaktor, Malmö, Sweden. Special attention is paid to the mechanism of bacterial reinfection and how it is influenced by deviations in can construction or can handling procedures. Methods of preventing bacterial reinfection at the most critical points in the canning operation are considered and certain guiding principles are derived.     

Electronmicroscopic Observations on the Degradation of Cellulose Fibres by Cellvibrio fulvus and Sporocytophaga myxococcoides

S ummary : Cellvibrio fulvus and Sporocytophaga myxococcoides were grown on different types of cellulose fibres and the degradation was followed by means of light and electron microscopy. The very compact fibres prepared from cotton were degraded slowly by C. fulvus. The bacteria penetrated into the lumen of the fibres, accumulated there in large numbers, and degraded the fibres from within. Sporocytophaga myxococcoides attacked fibres both from the outside and from within by making close contact with the cellulose. Lignin free pulp fibres, which have a very open structure, were rapidly degraded by both kinds of bacteria. Cellvibrio fulvus also degraded these fibres from within. It is concluded that structure of the fibre greatly influences the rate at which different kinds of cellulolytio bacteria decompose cellulose.