Biology of mammary fat pad in fetal mouse: capacity to support development of various fetal epithelia in vivo

Epithelia from the lobular part of submandibular salivary gland, glandular stomach, intestine and colon of 14-day C3H/HeN fetuses, and from pituitary gland and pancreas of 12-day fetuses were recombined with 14-day mammary fat pad precursor tissue and syngrafted under the kidney capsule. The normal organogenetic development typical of the epithelium occurred. The same epithelia taken from earlier stage fetuses did not develop normally. Thus, 14-day fetal mouse mammary fat pad precursor tissue has the capacity to support normal organogenesis of various fetal epithelia of developmentally advanced stages. This supportive capacity is decreased in the fat pad precursor tissue of 17- to 18-day fetal mice and is entirely lost postnatally.     

Involvement of the acyl chain of ceramide in carbohydrate recognition by an anti-glycolipid monoclonal antibody: the case of an anti-melanoma antibody,M2590, to GM3-ganglioside

The effect of the chain length of the fatty acid residue of the ceramide moiety of ganglioside G_M3 on the binding ability of monoclonal antibody M2590, which is specific for the carbohydrate structure of G_M3-ganglioside, was examined by means of a direct binding assay on thin layer chromatography plates (TLC immunostaining) and a quantitative enzyme-linked immunosorbent assay (ELISA). Derivatives of G_M3 with a long fatty acid chain reacted with the M2590 antibody, but those with a short fatty acid chain showed no reaction in either assay system. These results suggested that the acyl fatty acid moiety of the ganglioside played an important role in the formation or maintenance of the antigenic structure of the carbohydrate moiety of the ganglioside.     

The production of pheromone clouds by spraying in the melon fly,Dacus cucurbitae coquillett (Diptera: Tephritidae)

Pheromone clouds sprayed by melon fly males were visually detected by focusing a beam of light at them during dusk when the males were vibrating their wings. The clouds were sprayed to the front, rear and upper sides of the male. We found that special morphological structures are used for spraying the pheromone clouds. When a male melon fly engages in calling behavior, sex pheromone droplets are excreted from his anus. This excretion is wiped off with the tarsus of his hind leg, and then it is deposited on the sexually dimorphic cubital cell hairs on the wing. During wing vibration, the targal bristles on the 3rd abdominal segment, which are peculiar to males, are rubbed against the specialized hairs of the cubital cell. Calling males sprayed clouds of pheromone with these actions. This paper was presented at the 32nd Annual Meeting of the Japanese Society of Applied Entomology and Zoology (Kochi, April, 1988).     

Replication of ColE2 and ColE3 plasmids: Two ColE2 incompatibility functions

Summary We have identified and localized two incompatibility determinants (IncA and IncB) within a 1.3 kb segment of ColE2 sufficient for autonomous replication. The IncA determinant is localized in a region shorter than 250 bp and expresses incompatibility against both ColE2 and ColE3. The region which determines sensitivity to the IncA determinant seems to overlap with the region specifying the IncA determinant. The expression of the trans-acting factor(s) specifically required for replication of ColE2 interferes with expression of the IncA determinant against ColE2 but not against ColE3. The IncA determinant might be at least partly responsible for the copy number control of the plasmid. The IncB determinant is localized in a 50 bp region (origin) which is sufficient for initiation of replication in the presence of the trans-acting factor(s). The IncB determinant is specific for ColE2 and seems to be due to titration of the trans-acting essential replication factor(s) by binding.     

Generation of 19 STS markers that can be anchored at specific sites on human chromosome 21.

Sequence-tagged sites (STSs) are short stretches of DNA that can be specifically detected by the polymerase chain reaction (PCR) and can be used to construct long-range physical maps of chromosomal DNA. These STSs can be detected by PCR assays developed by reference to data obtained from the sequencing of restriction fragment length polymorphism-DNA markers for chromosome 21, which were derived from recombinant lamba-phage and plasmid clones made from DNA of a human-hamster hybrid cell line. In this report, we describe the generation of 19 new STSs that are specific for human chromosome 21.     

Association of Lps gene with natural resistance of mouse macrophages against Legionella pneumophila

We have cloned a 1.6-kb region of chromosomal DNA from Thermoplasma acidophilum into Escherichia coli using as a probe part of the Methanococcus vannielii fus-gene. The sequence of the clone was highly homologous to part of the corresponding Methanococcus vannielii gene. By chromosome walking, a 4.7-kb EcoRI fragment containing the complete gene was isolated. Nucleotide sequencing revealed an open reading frame of 2196 nucleotides. The deduced amino acid sequence contains the known peptide sequence around the ADP-ribosylation site of T. acidophilum elongation factor 2, which unequivocally confirms that the fus-gene has been cloned. The amino acid sequence was compared to that of hamster and E. coli, as well as to known archaebacterial EF-2 sequences.     

Mucociliary clearance in chronic sinusitis: related human nasal clearance and in vitro bullfrog palate clearance

Nasal mucociliary clearance was measured in both healthy subjects and patients with chronic sinusitis using saccharin granule technique. Nasal mucociliary transit time (ST) was significantly slower in the patients with chronic sinusitis compared with that in controls (p less than 0.005). Nasal mucus collected from each nasal cavity was used for in vitro bullfrog palate clearance studies and compared to the in vivo nasal ST. Mucociliary clearance rate (MTR) on frog palate was 12.5 +/- 2.5 mm/min in the mucus from control subjects, 6.1 +/- 1.5 mm/min in the mucus from the patients. The difference was statistically significant (p less than 0.005). The MTR on frog palate in the patients whose nasal ST was within normal range was significantly slower than that in controls (p less than 0.005), but not significantly different from that in the patients whose nasal ST was over the normal range. These results suggest that the nasal mucous properties which decreased the mucociliary clearance on frog palate did not contribute to the mucociliary clearance of the patients who had a normal one. No significant correlation existed between MTR on frog palate and nasal ST in both control and chronic sinusitis. In chronic sinusitis patients, decelerated nasal ST was recovered significantly by normal saline nebulization compared with the value before the nebulization (p less than 0.01). None of the significant change of ST was observed in control before and after the nebulization.     

Structure of chicken 16-kDa beta-galactoside-binding lectin. Complete amino acid sequence, cloning of cDNA, and production of recombinant lectin

The complete primary structure of chicken 16-kDa beta-galactoside-binding lectin (C-16) was determined. It was composed of 134 amino acid residues and has an acetylated NH2 terminus. A cDNA was also cloned, but no signal sequence was found in the initiator region. The initiator methionine remained as the NH2 terminus of the mature lectin. Although C-16 is distinct from chicken 14-kDa beta-galactoside-binding lectin (C-14), it proved to be a member of the vertebrate 14-kDa-type lectin family. Comparison of the primary structures between the vertebrate 14-kDa-type lectins suggests that C-14 and C-16 were produced by gene duplication of an ancestral lectin gene at a time close to the divergence of birds and mammals. Northern and Southern blot analysis indicated that these isolectins are encoded by individual genes which are differently regulated during the development of the embryo. A recombinant C-16 lectin was produced in Escherichia coli. The product was indistinguishable from the authentic C-16 lectin except that the NH2 terminus of the former was found to begin with free methionine.     

Hormonal induction of all stages of spermatogenesis in germ-somatic cell coculture from immature Japanese eel testis

In cultivated male eel, spermatogonia are the only germ cells present in testis. Our previous studies using an organ culture system have shown that gonadotropin and 11-ketotestosterone (11-KT, a potent androgen in teleost fishes) can induce all stages of spermatogenesis in vitro. for detailed investigation of the control mechanisms of spermatogenesis, especially of the interaction between germ cells and testicular somatic cells during 11-KT-induced spermatogenesis in vitro, we have established a new culture system in which germ cells and somatic cells are cocultured after they are aggregated into pellets by centrifugation. Germ cells (spermatogonia) and somatic cells (mainly Sertoli cells) were isolated from immature eel testis. Coculture of the isolated germ cells and somatic cells without forming aggregation did not induce spermatogenesis, even in the presence of 11-KT. In contrast, when isolated germ cells and somatic cells were formed into pellets by centrifugation and were then cultured with 11-KT for 30 days, the entire process of spermatogenesis from premitotic spermatogonia to spermatozoa was induced. However, in the absence of 11-KT in the culture medium spermatogenesis was not induced, even when germ cell and somatic cells were aggregated. These results demonstrate that physical contact of germ cells to Sertoli cells is required for inducing spermatogenesis in response to 11-KT.     

Negative-ion fast atom bombardment and electrospray ionization tandem mass spectrometry for characterization of sulfated and sialyl Lewis-type glycosphingolipids

Structural characterization of sulfated and sialyl Lewis (Le)-type glycosphingolipids performed by fast atom bombardment (FAB) and electrospray ionization (ESI) mass spectrometry is described. Both FAB and ESI collision-induced dissociation tandem mass spectrometry (CID-MS/MS) of acidic glycosphingolipids allowed identification of the sulfated or sialyl sugar, and provided information on the saccharide chain sequence. The negative-ion tandem FABMS of sulfated Le-type glycosphingolipids having the non-reducing end trisaccharide ion as the precursor can be used to differentiate the Le^a- and Le^X-type oligosaccharides. The ESI CID-MS/MS of multiple-charged ions provided even more detailed structural information, and some of the useful daughter ions appeared with higherm/z values than the precusor because of a lower charge-state. These methodologies can be applied to the structural analyses of glycoconjugates with much larger molecular masses and higher polarity, such as the poly-sulfated and sialyl analogues.Abbreviations CID collision-induced dissociation - ESI electrospray ionization - FABMS fast atom bombardment mass spectrometry - Fuc fucose - Gal galactose - GlcNAc N-acetylglucosamine - Le Lewis - Le^a Lewis^a - Le^X Lewis^X - MS/MS mass spectrometry/mass spectrometry - NeuAc N-acetylneuraminic acid - 3-SO₄-Le^a 3-sulfated Le^a pentaosyl ceramide - 3-SO₄-Le^X 3-sulfated Le^X pentaosyl ceramide - 2,3-SO₄-Le^X 2,3-disulfated Le^X pentaosyl ceramide - 3-S-Le^a 3-sialyl Le^a pentaosyl ceramide - 3-S-Le^x 3-sialyl Le^X heptaosyl ceramide - 3-S-Le^X-Le^X 3-sialyl-Le^x-Le^x octaosyl ceramide.