New genus and species of the family stichaeidae from Hokkaido,Japan

Specimens of a new genus and species of the stichaeid fish,Leptostichaeus pumilus, were collected from the Okhotsk Sea off Hokkaido in Japan. The present new genus and species clearly differs from all the other genera and species of the stichaeid fishes in the following characters: 3 or 4 pectoral fin rays; 10 or fewer caudal principal rays; 79–82 dorsal spines; no pelvic fin; last interneural spine supporting a single dorsal spine; infraorbital, occipital and lateral line canals absent; moderate size of dorsal spine shorter than eye diameter; membranes of dorsal and anal fins widely connected with caudal fin; a large black spot divided by a yellow band present just above gill cover.     

Study on membrane recycling in the rat visceral yolk-sac endoderm using concanavalin-A conjugates

Summary The internalization and intracellular movements of apical-cell-membrane material were investigated in the endodermal cells of cultured visceral yolk-sacs of rats (whole-embryo culture; explanted at 10.5 days of gestation and cultured for 24h) using horseradish peroxidase- and ferritin-labelled concanavalin A (Con-A HRP, Con-A Fer). When visceral yolk-sac endoderm was exposed to Con-A HRP or Con-A Fer for 5 min at 4°C, the apical cell membranes containing a well-developed fuzzy coat were heavily labelled, whereas apical vacuoles, lysosomes and apical canaliculi were not. Incubation of Con-A-labelled endoderm for 5 60 min at 20° and 37°C in Con-A-free serum resulted in a temperature-dependent internalization of membranebound lectin into coated vesicles, apical vacuoles and lysosomes, and the apical cell membranes were cleared of the heavy labelling. With increasing incubation time, the number of labelled vacuolar structures and the intensity of their labelling decreased gradually, whereas the number of labelled apical canaliculi increased. Thus, after 30 and 60 min at 37°C, most of the apical canaliculi contained high concentrations of the markers. It was possible to observe labelled apical canaliculi that were in continuity with labelled apical vacuoles and lysosomes as well as with the apical cell membrane. These findings in rat endodermal cells indicate that constitutents of the apical cell membrane are internalized in apical vacuoles and lysosomes, and are then brought back to the apical cell membrane by the apical canaliculi, which concentrate and store this membrane material.Supported by the Deutsche Forschungsgemeinschaft (SFB 105)     

Gene structures of low-neurovirulent vaccinia virus LC16m0, LC16m8, and their Lister original (LO) strains

Vaccinia viruses LC16m0 and LC16m8 are temperature-sensitive and low-neurovirulent variants derived from the Lister (Elstree) (LO) strain. Analyses of genome DNAs by digestion with restriction endonucleases and cross-hybridization of the digested fragments revealed that LC16m0 and LC16m8 possess a new XhoI site in addition to the 14 XhoI sites of LO. This new site is located at about 12 X 10(6) daltons from the right terminal end. There was no significant difference in the genome structures between the LC16 variants and LO except the new XhoI site and their terminal fragments which were not identified in LO owing to their heterogeneity. With HindIII digested fragments, there was no difference among the three viruses. This complete mapping raised the possibility that the putative gene responsible for temperature sensitivity and neurovirulence is located at the region of the XhoI site found in LC16m0 and LC16m8.     

Mechanism of phorbol myristate acetate-induced lymphotoxin production by a human T cell hybridoma

Various hydroxyl radical scavengers markedly inhibited phorbol myristate acetate (PMA)-induced lymphotoxin (LT) production by a human T cell hybridoma, AC5-8. Among those we tested, tetramethylurea (TMU) was the most potent scavenger, and it was revealed that TMU must be added before 2 h have elapsed after PMA addition in order for LT production to be inhibited. In concordance with this fact, soluble NADPH dependent O2- forming enzyme(s) were activated several fold by PMA. PMA also induced DNA strand breaks, a process markedly inhibited by TMU. As expected, ADP-ribosyl transferase (ADPRT), which is well known to require DNA strand breaks for its enzymatic activity, was activated by PMA treatment. In addition, specific inhibitors for ADPRT, namely 3-amino-benzamide and nicotinamide, inhibited PMA-induced LT production. Taken together, these three successive events, activation of soluble NADPH dependent O2- forming enzyme(s), DNA strand breaks and activation of ADPRT, may be required for PMA-induced LT production by AC5-8.     

Inhibition by estrogen of autofeedback regulation of prolactin secretion

The effect of estradiol-17 beta (E2) on autofeedback regulation of prolactin (PRL) secretion was tested in ovariectomized rats after s.c. implantation of an (E2)-containing or empty silastic capsule, followed by i.v. injection of bovine PRL (b-PRL) or bovine serum albumin (BSA; 500 micrograms/100 g B.W.). Implantation of an E2 capsule (day 0), 2.5 mm or 5.0 mm in length, produced plasma E2 concentrations of 79 +/- 6 (9) and 140 +/- 8 pg/ml (8), respectively. Assay of PRL in plasma samples collected at 1 h intervals between 1100-1800 h on days 3, 4 and 5, after E2 capsule implantation showed a daily afternoon PRL surge. Empty capsule-treated rats did not show any afternoon PRL surge. Injection of b-PRL, but not BSA, at 1200 h on day 3 reduced basal PRL release both on days 3 and 4 in empty capsule-treated rats. In ovariectomized rats treated with a smaller E2 capsule (2.5 mm), b-PRL injection at 1200 h on day 3 reduced the amplitude of the afternoon surge of PRL and the total amount of PRL released on day 4. b-PRL, however, was ineffective in reducing PRL release in rats bearing the large E2 capsule (5.0 mm). These results suggest that high E2 levels in the blood can block the negative feedback action of PRL on PRL release.     

Serologic dissection of HLA-D specificities by the use of monoclonal antibodies

To study the gene products of the HLA complex, we produced two monoclonal antibodies, termed HU-18 and HU-23. They were active in complement-dependent cytotoxicity and detected B-cell alloantigens encoded by a locus (or loci) linked to HLA. When three types of HLA-DR4 homozygous B-cell lines with different HLA-D specificities were tested for reactivity with HU-18 and HU-23, they displayed distinct reaction patterns depending on the HLA-D specificities they possessed: EBV-Wa (HLA-DYT homozygous), negative for both HU-18 and HU-23; KT2 and KOB (HLA-DKT2 homozygous), positive only for HU-18; and ER (HLA-Dw4 homozygous), positive for both. These differential reaction patterns were further confirmed by testing against a panel of 17 HLA-DR4-positive peripheral blood lymphocytes with known HLA-D specificities. Thus, these monoclonal antibodies allow us to identify HLA-DYT, HLA-DKT2, and HLA-Dw4 solely by serologic methods. This is the first clearcut serologic identification of these three HLA-DR4-associated HLA-D specificities, which have been indistinguishable by conventional serology and identified only by cellular techniques. It is hoped that immunochemical investigations using HU-18 and HU-23 will advance our understanding of the HLA-D region on a molecular level.     

Human T-cell hybridomas producing lymphokines. II. Enhancement of lymphotoxin secretion from human T-cell hybridomas by phorbol myristate acetate

Human lymphotoxin (LT)-producing T-cell hybridomas were constructed by fusing concanavalin A-activated human peripheral blood lymphocytes with emetine-actinomycin D-pretreated human acute lymphatic leukemia cells. LT secretion from these hybridomas was considerably enhanced by stimulation with phorbol-12-myristate-13-acetate (PMA) and concanavalin A or PMA alone. A study using cloned hybrid lines revealed that PMA/Con A acted directly on the LT-producing clones. Furthermore, PMA/Con A stimulated A-B9-24, one of the cloned hybridomas, and secreted fourfold larger amounts of LT under serum-free conditions than under serum-containing conditions. However, MIF/MAF and LT-producing cloned hybrid line E10-20 secreted rather decreased amounts of MIF/MAF when stimulated with PMA, while the LT secretion from the same hybridoma was enhanced with PMA.     

Step response of lung surface-to-volume ratio by light-scattering stereology

By means of backscattered light from a pointlike source on the pleural surface, we investigated the dynamic behavior of the surface-to-volume ratio (S/V) in excised dog lobes subjected to small volume steps both in and out on both the inflation and deflation limb of standard pressure-volume maneuvers. The technique utilizes the established correlation of the pattern of backscattered light with morphometric mean linear intercept and is suitable for dynamic studies. We hypothesized that 1) there would be a difference in the timing of stress relaxation or recovery between alveolar septa and the fibromuscular tissue in the alveolar duct that would reveal itself as a temporally changing S/V after a step-volume change and 2) that geometric hysteresis (looping of S/V with volume), as seen with large volume excursion histories, would be similarly present in small tidal volume loops. Our experimental results contradicted both hypotheses. In particular, we found virtually no change in S/V after a step-volume change, even in the presence of substantial stress adaptation. In addition, when geometric hysteresis of small loops was present, it was always in the sense opposite to the geometric hysteresis of large loops. We conclude that 1) there is a functional "matching" of the stress-adaptive timing between alveolar septa and ductal mouths and 2) during small volume looping, the stress hysteresis (looping of stress with volume) in the ductal tissue may be larger than that of the septa, including surface tension.     

Factors affecting the use of chloramphenicol acetyltransferase as a marker for Brassica genetic transformation

The CAT gene which codes for the enzyme chloramphenicol acetyltransferase was found to be ineffective as a reporter gene in cells and tissues of Brassica species. High levels of endogenous CAT activity were found to be widespread among this genus and did not appear to be distributed in a tissue- or cell-specific manner. Moreover, the presence of an inhibitor of CAT activity was discovered in Brassica napus and Brassica juncea. This inhibitor appeared to act selectively on bacterial CAT in transgenic plants. These findings provided an explanation for difficulties experienced in the detection of transgenic CAT activity in B. napus.     

Close linkage of MEN2A with RBP3 locus in Japanese kindreds

Summary The gene responsible for multiple endocrine neoplasia type 2A (MEN2A) has recently been assigned to the pericentromeric region of chromsome 10 in European Caucasian kindreds by linkage analysis using a DNA marker, interstitial retinol-binding protein 3 (RBP3). We have found tight linkage between the MEN2A and RBP3 loci in Japanese MEN2A kindreds. The maximum lod score is 5.19 at a recombination fraction of 0.00. This result suggests that mutation of a certain gene close to RBP3 is responsible for MEN2A irrespective of ethnic backgrounds.