Irradiation-induced effects on the innervation of rat salivary glands: Changes in enkephalin- and bombesin-like immunoreactivity in ganglionic cells and intraglandular nerve fibers

When treating head and neck for cancer with the use of radiotherapy the salivary glands are usually within the treatment volume with ensuing dryness and discomfort. Since the autonomic nervous system is of pivotal importance for the salivary gland function and integrity, the irradiation-induced effects may involve an influence on the innervation of salivary glands. Therefore, the rat submandibular gland, including the submandibular ganglionic cells, has been subjected to immunohistochemical examination with respect to expression of neuropeptides following fractionated irradiation with high energy photons. A markedly enhanced expression of bombesin- and leu-enkephalin-(ENK)-like immunoreactivities (LI) in the ganglionic cells and a pronounced increase in the number of nerve fibers showing these immunoreactivities in the submandibular gland tissue following irradiation were observed 10 days after treatment. On the other hand, no changes in the patterns of VIP (vasoactive intestinal polypeptide)- and NPY (neuropeptide Y)-immunoreactivities occurred. Thus, the present study shows that alterations in the expression of certain neuropeptides take place in the submandibular gland and its associated ganglionic cells in response to irradiation of the head and neck region. These changes may add further explanation to the inherent radiosensitivity of salivary glands.     

Ca-dependent K channels in exocrine salivary glands

In the last 15 years, remarkable progress has been realized in identifying the genes that encode the ion-transporting proteins involved in exocrine gland function, including salivary glands. Among these proteins, Ca²⁺-dependent K⁺ channels take part in key functions including membrane potential regulation, fluid movement and K⁺ secretion in exocrine glands. Two K⁺ channels have been identified in exocrine salivary glands: (1) a Ca²⁺-activated K⁺ channel of intermediate single channel conductance encoded by the KCNN4 gene, and (2) a voltage- and Ca²⁺-dependent K⁺ channel of large single channel conductance encoded by the KCNMA1 gene. This review focuses on the physiological roles of Ca²⁺-dependent K⁺ channels in exocrine salivary glands. We also discuss interesting recent findings on the regulation of Ca²⁺-dependent K⁺ channels by protein–protein interactions that may significantly impact exocrine gland physiology.     

Hormonal control of salivary gland degeneration in the ixodid tick Amblyomma hebraeum

Under normal circumstances, salivary glands of female ixodid ticks begin degenerating within hours of completing the blood meal. We have monitored cytological, functional and biochemical changes in the tissue which are diagnostic of the degenerative process. Although ultimately degeneration also befalls salivary glands of partially fed ticks removed prematurely from the host, the process is considerably delayed. When we transplanted salivary glands from partially fed ticks into the haemocoels of replete specimens, autolysis was induced in the donor tissue, whereas such was not the case when similar glands were transplanted to the haemocoels of other partially fed ticks. We thus suggest that a humoral factor is involved in postprandial resorption of the salivary glands. Succinate dehydrogenase activity decreases, and acid phosphatase activity increases in the salivary glands as a function of time post-engorgement. However, these enzyme assays are not sensitive enough to detect the earliest stages of autolysis.     

The inhibiting effect of the queen bee (Apis mellifera L.) foot-print pheromone on the construction of swarming queen cups

Experiments were conducted to determine the rôle of population density of queenright honey bee colonies, and that of the queen bee pheromonal secretions, on the induction and inhibition of swarming queen cup construction during swarming and non-swarming seasons. Construction of queen cups was induced experimentally in overcrowded queenright colonies, during winter, which is a non-swarming season. This construction was induced by high population density of bee workers: above a threshold of 2.3 bee workers/ml there was a relationship between the number of cups constructed and the colony density. During the swarming season a relationship was established between the free volume of a hive (population density) and the number of queen cups constructed: 1.5 cups in a colony that occupied 80,960 ml, compared with 77 cups in a colony hived within a volume of 20, 240 ml. Observations of the queen's movements upon combs in colonies of high and normal population densities showed that in an overcrowded colony the queen bee was almost absent from the bottom edges of the comb, where queen swarming cups and cells are constructed. The tarsal glands of queens are located in the fifth tarsomere and the glandular oily secretion is deposited by the foot-pads upon the combs surface. The rate of secretion by the queen's tarsal glands was about 13 times higher than by those of the workers. A bioassay for testing the inhibitory effects of the queen's glandular extracts on the construction of queen cups was developed. It was based on increasing worker bee population densities, and can be used effectively throughout the year in a subtropical climate.The application of tarsal and mandibular glands' secretion to comb bottom edges in overcrowded colonies (bioassay) caused the inhibition of queen cup construction. None of these two secretions affected construction of these cups when applied separately. We presume that due to colony overcrowding the queen bee is unable to deposit the non-volatile secretions from tarsal glands along the comb edges and that the deficiency of the foot-print pheromone triggers the construction of swarming cups along the non-inhibited areas.     

Successful Ablation of Antero-septal Accessory Pathway in the Non-Coronary Cusp in a Child

A 15-year-old boy with Wolff-Parkinson-White syndrome underwent an electrophysiology study for symptoms of palpitations and persistence of pre-excitation during peak exercise. He was detected to have right antero-septal accessory pathway with relatively long effective refractory period and no inducible tachycardia. He had only transient normalization with cryoablation. Eight months later, he presented again with two episodes of seizures with preceding palpitations. Neurology evaluation was unremarkable with a normal electroencephalogram. In view of his symptoms in association with evidence of pre-excitation, he underwent a second electrophysiology study with ablation. Cryoablation in the anterior septum again achieved only transient normalization. Mapping in the non-coronary cusp identified an earliest accessory pathway potential. RF ablation was performed in the non-coronary cusp with immediate normalization of his electrocardiogram. At 6 month follow-up, he continues to have no pre-excitation on his EKG. Ablation of the anteroseptal accessory pathway in the non-coronary cusp can be safely performed in patients' refractory to conventional ablation sites and techniques.     

The Bvg accessory factor (Baf) enhances pertussis toxin expression in Escherichia coli and is essential for Bordetella pertussis viability

Pertussis toxin expression in the Gram-negative respiratory pathogen, Bordetella pertussis, is regulated by the BvgAS two-component system. Previous studies suggested that an additional gene encoding a Bvg accessory factor (Baf) was required, along with BvgAS, for expression of a ptx-lacZ fusion in Escherichia coli grown in rich medium. However, other studies showed that BvgAS is sufficient for ptx-lacZ expression in minimal medium. Here we show that Baf acts with BvgAS to further increase ptx-lacZ expression in E. coli grown in minimal media and this is concomitant with a two-fold increase in BvgA protein levels. Gene replacement experiments show that baf is essential for viability of B. pertussis, suggesting that Baf affects the expression of other genes in addition to ptx.     

Données cytochimiques et ultrastructurales sur les tubes sécréteurs des glandes de la glu chez Peripatus acacioi Marcus et Marcus (Onychophore)

Résumé Dans les glandes de la glu, formations propres aux Onychophores, les tubes sécréteurs comprennent un épithélium glandulaire entouré d'une enveloppe conjonctive et musculaire. L'enveloppe conjonctive, délimitée par des membranes basales de mucopolysaccharides neutres et de mucoprotéines, contient deux sortes de fibrilles: des fibrilles collagènes et un type particulier de fibrilles élastiques. Les fibres musculaires, éparses, d'orientation circulaire, montrent une organisation beaucoup plus rudimentaire que dans les muscles somatiques.L'épithélium glandulaire est formé de cellules prismatiques toutes semblables, à gros noyau polyploïde en position basale, avec nucléole très volumineux. L'ensemble du cytoplasme de ces cellules est chargé de ribonucléines sous forme d'ergastoplasme granulifère à citernes concentriques et de nombreux ribosomes libres. Les structures lamellaires concentriques de l'ergastoplasme, qui se différencient du côté basal, près des noyaux, s'accroissent dans la région médiane des cellules et se désorganisent à l'apex, en libérant des grandes quantités de ribosomes. La sécrétion de ces cellules est formée essentiellement de protéines qui s'accumulent dans la région apicale sans passer par l'appareil de Golgi, lequel est d'ailleurs peu développé. Ces protéines ne sont donc pas concentrées en granules de sécrétion, mais déchargées dans la cavité glandulaire, directement à l'état diffus, par l'intermédiaire d'épanchements cytoplasmiques de la face apicale cellulaire dans lesquels passent également de nombreux ribosomes libres. Polyploïdie, grand volume nucléolaire, hyperdéveloppement de l'ergastoplasme granulifère, abondance des ribosomes libres, non-intervention de l'appareil de Golgi et absence de concentration de la sécrétion en granules sont mis en relation avec la synthèse rapide et continue des protéines qui forment le principal constituant de la glu.

---

Cytochemical and ultrastructural data on the secretory tubes of the slime glands in Peripatus acacioi Marcus and Marcus (Onychophora)

Summary In the peculiar slime glands of the Onychophora, the secretory tubes consist of a glandular epithelium surrounded by a layer of connective and muscular tissue. The connective layer, bounded by basal membranes of neutral mucopolysaccharides and mucoproteins, contains two kinds of fibrils: collagenous fibrils and an especial type of elastic fibrils. The muscle fibers, which are scattered and circularly oriented, are more simply organized than those of the somatic muscles.The glandular epithelium is constituted by prismatic cells of the same type, with a large polyploid basally situated nucleus, containing a very large nucleolus. The cytoplasm of these cells is filled with ribonucleins in form of ergastoplasm and in numerous free ribosomes. Concentric lamellar structures of ergastoplasm, which originate basally close to the nucleus, are well developed in the central region of the cell and become disorganized at the apex, where they liberate great quantities of ribosomes. The secretion of these cells consists essentially of proteins, which accumulate in the apical region without passing through the poorly developed Golgi apparatus. These proteins, therefore, are not concentrated in secretory granules, rather they are released in a diffuse form, into the glandular cavity. They are discharged in cytoplasmic expansions detached from the apical region, together with a large quantity of free ribosomes. Polyploidy, large nucleolus, well developed granular ergastoplasm, abundance of free ribosomes, non-participation of the Golgi apparatus and lack of concentration in secretory granules are correlated with rapid and continuous synthesis of proteins which are the principal component of the slime.

Avec la collaboration technique de Mlle Eliana Parisi et l'aide de la Fundação de Amparo à Pesquisa do Estado de São Paulo.     

Serous cutaneous glands of the Pacific tree-frog Hyla regilla (Anura, Hylidae): patterns of secretory release induced by nor-epinephrine

The serous (poison) cutaneous glands of the Pacific tree-frog Hyla regilla were induced to release their product by 10(-3)M nor-epinephrine stimulation. After discharge structural and ultrastructural features of the cutaneous glands involved in release were observed. Furthermore, the discharged product, consisting of discrete, secretory granules, was collected and processed for transmission electron microscope analysis. As indicated by patterns found in the myoepithelium encircling the syncytial secretory unit, gland discharge is caused by contraction of the peripheral myocytes. Muscle cell compression dramatically affects the syncytium and results in degenerative changes, including expulsion of the secretory unit nuclei. Therefore, the structural collapse in depleted glands has been ascribed to the mechanical activity performed by the myoepithelium during discharge, rather than cytoplasm involution described in conventional, holocrine glands. TEM investigation revealed that the secretory granules collected after discharge maintain their peculiar traits: they consist of recurrent patterns of thin subunits, acquired during serous maturation and provided with remarkable structural stability.     

Homology modeling, docking studies and functional analysis of various azoreductase accessory interacting proteins of Nostoc sp.PCC7120

Azo dyes have become a threat to public health because of its toxicity and carcinogenicity. Azoreductase enzyme plays a pivotal role in the degradation of azodyes released by industrial effluents and other resources. The degradation pathway has to be studied in detail for increasing the activity of azoreductase and for better degradation of azo dyes. But the data available on cyanobacterial azoreductase enzyme and its degradation pathway are still very less. Therefore the present work explored the azoreductase pathway of the cyanobacterium Nostoc sp. PCC7120 for better understanding of the degradation pathway and the other accessory interacting proteins involved. The accessory interacting proteins of azoreductase from cyanobacterium Nostoc sp. PCC7120 were obtained from STRING database. The proteins do not have a comprehensive three dimensional structure and are hypothetical. The secondary structure and functional analysis indicated that the proteins are all soluble proteins, without disulphide bonds and have alpha helices only. The structural prediction and docking study showed that alr2106, alr1063 and alr2326 have best docking result which tally with the STRING database confidence score and thus these proteins could possibly enhance the azoreductase activity and better dye degradation. These results will pave way for further increase in azoreductase activity and for better understanding of the dye degradation pathway.     

Localization and associated histopathology of asexually proliferative Mesocestoides corti tetrathyridia (cestoda) infecting mouse mammary glands

Female mice of pregnant random-bred, or unmated BALB/c groups were exposed per os to Mesocestoides corti tetrathyridia and necropsied at various intervals postexposure. The right posterior subcutaneous fat pad with two mammary glands was removed from each mouse, stained, mounted whole and examined microscopically for localization of worms. The left fat pad/gland set was processed, sectioned and stained using standard histological techniques. In pregnant mice, tetrathyridia were localized primarily in the fat pad's posteroventral lobe. Unmated mice had few worms in the mammary glands or associated fat pads. The difference in infection levels between the two host groups may result from mouse strain difference or the pregnant condition of one group.