Isolation of two endo-beta-N-acetylglucosaminidases with different specificities from Pseudomonas sp.

Two endo-beta-N-acetylglucosaminidases (PI and PII) have been isolated from the culture fluid of Pseudomonas sp. The substrate specificity of the PI enzyme was very similar to that of Endo-H from Streptomyces plicatus. On the contrary, the PII enzyme had a novel substrate specificity that degraded both high-mannose type and hybrid type oligosaccharides derived from ovalbumin, and the core structure of complex type oligosaccharides derived from human transferrin and porcine pancreatic lipase.     

Hypothalamic potentials evoked by electrical stimulation of the vaginal cervix in the estrous guinea-pig

Summary Evoked potentials were recorded from the hypothalamus of acutely-prepared estrous guinea-pigs responding to electrical stimulation of the vaginal cervix. The latency ranged from 38 to 60 msec. The peak of the first positive wave appeared 50 to 90 msec after the stimulation, usually followed by a negative wave in 120 msec. These responses were obtained from the mid-hypothalamus. The cervical stimulation subsequently induced the release of hypophysial luteotropin (LTH) as indicated by the occurrence of pseudopregnancy. According to the results, the mechanism triggering hypothalamic potential changes was discussed in connection with the LTH secretion.Research Fellow of the Alexander von Humboldt-Foundation in 1967/68.     

Diets and body condition of polar cod (<Emphasis Type="Italic">Boreogadus saida</Emphasis>) in the northern Bering Sea and Chukchi Sea

To understand trophic responses of polar cod Boreogadus saida (a key species in Arctic food webs) to changes in zooplankton and benthic invertebrate communities (prey), we compared its stomach contents and body condition between three regions with different environments: the northern Bering Sea (NB), southern Chukchi Sea (SC), and central Chukchi Sea (CC). Polar cod were sampled using a bottom trawl, and their potential prey species in the environment were sampled using a plankton net and a surface sediment sampler. Polar cod fed mainly on appendicularians in the NB and SC where copepods were the most abundant in the environment, while they fed on copepods, euphausiids, and gammarids in the CC where barnacle larvae were the most abundant species in plankton samples on average. The stomach fullness index of polar cod was higher in the NB and SC than CC, while their body condition index did not differ between these regions. The lower lipid content of appendicularians compared to other prey species is the most plausible explanation for this inconsistency.     

Transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae.

Endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae has transglycosylation activity. Treatment of (Man)6(GlcNAc)2Asn with the enzyme in the presence of free N-acetylglucosamine gave a mixture of (Man)6GlcNAc and (Man)6GlcNAc beta 1----4GlcNAc mixture. N-Acetylglucosamine at the reducing end of the latter sugar chain was found by HPLC of the carbohydrate composition and of an exoglycosidase digest of the pyridylamino derivative of the reducing-end residue, and by 400 MHz 1H-NMR spectroscopy.     

Seed culture affects the completion time of L-lactate fermentation using electrodialysis culture

Electrodialysis culture (ED-C) and control culture of Lactococcus lactis IO-1 were inoculated with 3 and 12 h seed cultures. Regardless of seed culture age, control cultures needed 30 h for the completion of L-lactate fermentation. By contrast, the fermentation times for ED-Cs inoculated with 3 and 12 h seed cultures were reduced by 38 and 27% when compared to those of control cultures. Seed culture age can be varied to reduce the fermentation time for ED-C.     

Cytotoxicity and Glycan-Binding Profile of a <Emphasis Type="SmallCaps">d</Emphasis>-Galactose-Binding Lectin from the Eggs of a Japanese Sea Hare (<Emphasis Type="Italic">Aplysia kurodai</Emphasis>)

A divalent cation-independent 16 kDa d-galactose binding lectin (AKL-2) was isolated from eggs of sea hare, Aplysia kurodai. The lectin recognized d-galactose and d-galacturonic acid and had a 32 kDa dimer consisting of two disulfide-bonded 16 kDa subunits. Eighteen N-terminus amino acids were identified by Edman degradation, having unique primary structure. Lectin blotting analysis with horseradish peroxidase-conjugated lectins has shown that AKL-2 was a glycoprotein with complex type oligosaccharides with N-acetyl d-glucosamine and mannose at non-reducing terminal. Two protein bands with 38 and 36 kDa in the crude extract of sea hare eggs after purification of the lectin was isolated by AKL-2-conjugated Sepharose column and elution with 0.1 M lactose containing buffer. It suggested that the lectin binds with an endogenous ligand in the eggs. AKL-2 kept extreme stability on haemagglutination activity if it was treated at pH 3 and 70 °C for 1 h. Glycan binding profile of AKL-2 by frontal affinity chromatography technology using 15 pyridylamine labeled oligosaccharides has been appeared that the lectin uniquely recognized globotriose (Galα1-4Galβ1-4Glc; Gb3) in addition to bi-antennary complex type N-linked oligosaccharides with N-acetyllactosamine. Surface plasmon resonance analysis of AKL-2 against a neo-glycoprotein, Gb3-human serum albumin showed the k _ass and k _diss values are 2.4 × 10³ M^?1 s^?1 and 3.8 × 10^?3 s^?1, respectively. AKL-2 appeared cytotoxicity against both Burkitt’s lymphoma Raji cell and erythroleukemia K562. The activity to Raji by the lectin was preferably cancelled by the co-presence of melibiose mimicing Gb3. On the other hand, K562 was cancelled effectively by lactose than melibiose. It elucidated that AKL-2 had cytotoxic ability mediated glycans structure to cultured cells.