Development of mucociliary transport in the postnatal ferret trachea.

Little is known of the developmental aspects of mucociliary transport. Previous studies have documented that newborn ferret trachea has very few ciliated cells but numerous immature secretory cells in the epithelium and only rudimentary submucosal glands. Rapid and complete maturation occurs in the first postnatal month. This study examines mucociliary transport during this period of rapid maturation. We made direct observations of particle movement across the epithelium of ferret tracheas. No mucus transport could be demonstrated on the first day of life. Transport was discernible, although sporadic and slow, by 7 days and reached adult levels (10.7 +/- 3.7 mm/min) by 28 postnatal days. The emergence of transport capability correlated well with previously described developmental changes in ciliation, mucus secretion, and ion permeability and transport. Threshold mucus transport occurred at 1 wk of age when 20-25% of the surface cells are ciliated. The neonatal ferret appears to be a useful model for assessing integrated epithelial structure-function relationships that are important not only during early development but also during repair after airway injury involving deciliation.     

The genetic defect in multiple endocrine neoplasia type 2A maps next to the centromere of chromosome 10

Multiple endocrine neoplasia type 2A (MEN2A) is a rare cancer syndrome that is inherited in an apparently autosomal dominant fashion. Previous linkage studies had assigned the MEN2A locus to chromosome 10 in the pericentromeric region. We recently have described several new easily scorable RFLPs for the chromosome 10-specific alpha satellite DNA (the D10Z1) locus that is known, on the basis of previous in situ hybridization experiments, to lie at the centromere. We report here tight linkage between MEN2A and D10Z1, as demonstrated by a maximum lod score of 12.02 at the recombination frequency of zero (1-lod-unit support interval 0-4 cM), indicating that the genetic defect in MEN2A lies in the immediate vicinity of the centromere. By means of a set of ordered polymorphic DNA markers from the pericentromeric region, multipoint as well as pairwise linkage analyses place the MEN2A locus at the middle of a small region (approximately 11 cM) bracketing the centromere with FNRB (at 10p11.2) and RBP3 (at 10q11.2) on either side, providing further support for the centromeric location of the MEN2A locus. Marked sex difference in recombination frequencies exists in this pericentromeric region: significantly (P less than .01) more female than male crossovers were observed across all of the adjacent intervals D10S24-FNRB, FNRB-D10Z1, and D10Z1-RBP3. However, a sex difference was not seen in the 7-cM interval from RBP3 to D10S5, suggesting that large variation in the sex difference in recombination can occur over small chromosomal regions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antifeedant effects of azadirachtin and structurally related compounds on lepidopterous larvae

The antifeedant activity of azadirachtin, azadirachtin-derivatives and related limonoids was assessed in choice and no-choice bioassays against four species of Lepidoptera: Spodoptera littoralis, Spodoptera frugiperda, Heliothis virescens and Heliothis armigera. The choice bioassay showed that the feeding behaviour of S. littoralis was affected by more of the compounds than that of either S. frugiperda or H. virescens. H. armigera was the least affected. Azadirachtin and dihydroazadirachtin were the most potent of the 40 compounds tested. The results showed that hydrogenation of the C-22,23 double bond did not decrease antifeedant activity and the nature of the substitutes at C-1, C-3 and C-11 were important. Molecules with bulky substitutes at either C-22 or C-23 were usually ineffective antifeedants as were compounds lacking an epoxide. Compounds recorded as active antifeedants in the choice bioassay were not always as active in the no-choice test. The value of the bioassays in assessing the mode of action of the compounds is discussed.

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Résumé L'activité phagodissuadante de l'azadirachtine, de ses dérivés et des limonoïdes voisins sur 4 espèces de lépidoptères: Spodoptera littoralis, S. frugiperda, Heliothis virescens et H. armigera a été évaluée par des expériences avec et sans choix. Les expériences de choix ont montré que le comportement alimentaire de S. littoralis était modifié par plus de substances que celui de S. frugiperda ou H. virescens. Celui de H. armigera était le moins modifié. Les 2 substances les plus puissantes parmi les 40 examinées, ont été l'azadirachtine et le dihydroazadirachtine. Ces résultats montrent que l'hydrogénation de la double liaison C-22,23 ne réduit pas l'activité phagodissuadante et que la nature des substitutions en C-1, C-3 et C-11 sont importantes. Les molécules avec des substitutions volumineuses en C-22 ou C-23 sont généralement des phagodissuadants aussi inefficaces que ceux ayant perdu un époxide. Les substances notées comme phagodissuadants actifs dans les expériences de choix ne sont pas toujours aussi actives en absence de choix. La valeur des tests dans l'évaluation du mode d'action des substances est discuté.

     

The nitrogen requirements ofGluconobacter,Acetobacter andFrateuria

The nitrogen requirements of 96Gluconobacter, 55Acetobacter and 7Frateuria strains were examined. Only someFrateuria strains were able to grow on 0.5% yeast extract broth or 0.5% peptone broth. In the presence ofd-glucose ord-mannitol as a carbon source, ammonium was used as the sole source of nitrogen by all three genera. With ethanol, only a fewAcetobacter strains grew on ammonium as a sole nitrogen source. Singlel-amino acids cannot serve as a sole source of carbon and nitrogen for growth ofGluconobacter, Acetobacter orFrateuria. The singlel-amino acids which were used by most strains as a sole nitrogen source for growth are: asparagine, aspartic acid, glutamine, glutamic acid, proline and alanine. SomeAcetobacter andGluconobacter strains deaminated alanine, asparagine, glutamic acid, threonine, serine and proline. NoFrateuria strain was able to develop on cysteine, glycine, threonine or tryptophan as a sole source of nitrogen for growth. An inhibitory effect of valine may explain the absence of growth on this amino acid. No amino acid is “essential” forGluconobacter, Acetobacter orFrateuria.     

Immunocytochemical demonstration of nerve growth factor and histofluorescence of catecholaminergic nerves in the salivary glands of diabetic mice

Summary Nerve growth factor (NGF) was localized in the submandibular, sublingual, and parotid salivary glands of male and female diabetic mice and their normal littermates by immunoperoxidase staining usingp-phenylenediamine-pyrocatechol as a chromogen for the cytochemical demonstration of peroxidase activity. In the normal male submandibular gland, immunoreactive NGF was localized in the apical regions of granular, intercalated and collecting duct cells, while in the normal female submandibular gland, NGF was present throughout the cytoplasm of granular duct cells. The localization of NGF in the diabetic male and female submandibular glands was similar and resembled that of the normal female. NGF immunoreactivity was also observed in the striated duct cells in the sublingual and parotid glands of all four types of mice.The sympathetic innervation of the submandibular glands of normal and diabetic mice was demonstrated using glyoxylic acid-induced histofluorescence. The pattern of sympathetic innervation and the intensity of catecholamine fluorescence was consistently different in the four types of mice. In the normal male submandibular gland the fluorescence was very intense, particularly in nerves adjacent to the granular ducts. In the normal female submandibular gland, the fluorescence was weak, while in the diabetic male and female the fluorescence was moderate.The correlation between the intensity of the immunocytochemical staining for NGF and the catecholamine fluorescence adjacent to the granular ducts suggests a trophic influence of the NGF-containing granular ducts on their sympathetic innervation.     

Selective killing of Leishmania infected mouse macrophages by 6-methylpurine 2′-deoxyriboside

6-methylpurine 2′-deoxyriboside killed mouse macrophages infected with amastigotes of $\text{Leishmania donovani}$ and $\text{Leishmania mexicana}$, but did not affect the growth of non-parasitized cells. $\text{Leishmania}$ extracts cleaved the non-toxic 6-methylpurine 2′-deoxyriboside to 6-methylpurine, a potent adenine antimetabolite for mammalian cells. By eliminating macrophages latently infected with $\text{Leishmania donovani}$ amastigotes, 6-methylpurine 2′-deoxyriboside could augment the effects of leishmanicidal agents $\text{in vivo}$.     

Cytochromes c-556 from three genetic races of Agrobacterium. Purification and comparison of their properties

1. The soluble cytochromes c-556 from three strains of Agrobacterium tumefaciens, B6, II Chrys and Apple 185 have been purified to homogeneity. The strains are representative members of the three main genetic races of Agrobacterium. The purity of the final preparations was established by electrophoresis with an without sodium dodecyl sulphate, by analytical isoelectric focusing and ultracentrifugation, and by N-terminal analysis. 2. Properties of these cytochromes were compared wih those of cytochrome c-556 from A. tumefaciens, strain B2a, a member of the same genetic race as strain B6. The four cytochromes are monohaem proteins with molecular weights of about 12300 (determined by four different methods). The isoelectric points of those from strains B6 and B2a are identical at pH 5.5, but they differ from the cytochromes of the other genetic races: cytochrome c-556 from strain Apple 185 is more acidic (ph 5.2) and that from strain II Chrys more basic (pH 6.2). The cytochromes from strains b6 and B2a have very similar but not identical amino acid compositions; both of them differ more from Apple 185 than from II Chrys c-556. 3. Comparison of the tryptic, chymotryptic and thermolytic fingerprints of cytochrome c-556 from strains B2a and II Chrys reveals strong homology between the primary structures of these cytochromes. Therefore and because of the sequence identity of the first eight residues, the cytochromes c-556 from strains II Chrys, B6 and B2a are most likely C-terminal haem-bound, of the same type as the cytochrome c' from photosynthetic bacteria.