Induction of the acrosome reaction in ejaculated goat spermatozoa by preincubation in chemically defined medium

The aim of the present study was to examine the effects of the elimination of energy substrate from the medium and the effects of the preincubation vessel, temperature, and time on the induction of the acrosome reaction in ejaculated goat spermatozoa in chemically defined medium. Washed spermatozoa were resuspended in Brackett-Oliphant (BO) medium or substrate-free BO medium to give a high concentration and preincubated in open test tubes or sealed glass tubes at 37.0 or 39.5 degrees C for 1, 2, or 3 h. Sperm acrosome reaction was evaluated using a simplified triple-stain technique and a hamster test. It was found that the goat sperm acrosome reaction occurred more readily in the sealed glass tubes than in open test tubes, in substrate-free BO medium than in BO medium, and at 39.5 than at 37.0 degrees C. During preincubation with substrate-free BO medium in sealed glass tubes at 39.5 degrees C, the optimum time necessary to induce the acrosome reaction in goat spermatozoa was 2-3 h.     

Evidence suggesting that L-fucose is part of a recognition signal for sperm-zona pellucida attachment in mammals

Experiments were designed to test the effects of simple sugars and complex polysaccharides on the attachment of mammalian spermatozoa with the zona pellucida. In the guinea pig, L-fucose was a twofold better inhibitor of the attachment compared to other sugars at 50 mM. Fucoidin, an algal polysaccharide rich in sulfated L-fucose, was a very potent inhibitor, completely blocking attachment at a concentration of 100 μg/ml. Several other highly sulfated glycosaminoglycans showed no inhibitory activity, suggesting the fucoidin effect was not simply due to its charge or sulfate. In addition, fragments of fucoidin, generated by partial hydrolysis and isolated using Biogel P-2, were nearly as inhibitory as the native molecule on a weight basis. Fucoidin also inhibited sperm-zona attachment in the hamster and human; thus, its effect is not species specific. The data suggest that L-fucose may be part of a recognition signal between mammalian gametes.     

Gas chromatographic—mass fragmentographic determination of homopantothenic acid in plasma

A gas chromatographic—mass fragmentographic method was developed for the determination of homopantothenic acid in plasma. Acidified plasma was deproteinized by extraction with chloroform and subsequently the aqueous layer was extracted with ethyl acetate. The organic layer containing homopantothenic acid was reduced to dryness, and the resulting residue was redissolved in N,O-bis(trimethylsilyl)trifluoroacetamide—pyridine solution to allow trimethylsilylation. Aliquots of this solution were injected into the gas chromatograph—mass spectrometer and analyzed by the selected ion monitoring method using l-ascorbic acid as an internal standard. The detection limit for homopantothenic acid was 5 ng/ml of plasma.A precise and sensitive assay for the determination of homopantothenic acid in plasma was established.     

(−)-Epilamprolobine and its N-oxide,lupin alkaloids from Sophora tomentosa

From the fresh leaves of Sophora tomentosa, three new lupin alkaloids, (?)-epilamprolobine, (+)-epilamprolobine N-oxide and 5-(3′-methoxycarbonylbutyroyl)aminomethyl-trans-quinolizidine N-oxide, have further been isolated along with (+)-matrine, (+)-matrine N-oxide, (+)-sophocarpine N-oxide, (?)-anagyrine, (?)- baptifoline, (?)-cytisine, (?)-N-methylcytisine, (?)-N-formylcytisine, (?)-N-acetylcytisine and (±)-ammodendrine. The absolute configurations of (+)-epilamprolobine N-oxide (1R:5R:6S) and (?)-epilamprolobine (5R:6S) have also been established by spectroscopic data and by comparison with synthetic (+)-epilamprolobine (5S:6R)derived from (?)-lupinine (5R:6R). (?)-Epilamprolobine is a diastereomer of (+)-lamprolobine (5R:6R) in Lamprolobium fruticosum and 5-(3′-methoxycarbonylbutyroyl) aminomethyl-trans-quinolizidine N-oxide is presumed to be an artefact. A biosynthetic pathway for the formation of (?)-epilamprolobine is also proposed.     

Behavior of the Nucleoside Triphosphate Diphosphatase in Pea Cotyledon Chromatin during Germination

The behavior of nucleoside triphosphate diphosphatase (NTDPase)of pea cotyledon chromatin was investigated by a comparisonof the activities of amylase and protease in the cytoplasm.The activities of NTDPase and amylase increased from the 3rdto the 5th day during germination, but the activity of proteaseincreased more rapidly at the stage of imbibition. The inhibitorsactinomycin D and cycloheximide markedly inhibited the increasein the activities of NTDPase and amylase, but their inhibitionof protease was much less. Inhibition of germination by saltstress was accompanied by reductions in the increases in NTDPaseand protease activities, but not by a reduction in amylase activity.Removal of the embryo from dormant seeds had the same effecton these activities as salt stress did. These results suggestthat formation of the NTDPase in the chromatin of the cotyledonis under the control of the embryonic tissue. (Received October 22, 1980; Accepted January 20, 1981)     

Effects of the umuC36 mutation on ultraviolet-radiation-induced base-change and frameshift mutations in Escherichia coli

The effects of the umuC36 mutation on the induction of base-change and frameshift mutations were studied. An active umuC gene was necessary in either the uvr⁺ or uvr^? strains of Escherichia coli K12 for UV- and X-ray-induced mutations to His⁺, ColE^R and Spc^R, which are presumably base-change mutations, but it was not essential for ethyl methanesulphonate or N-methyl-N′-nitro-N-nitrosoguanidine-induced His⁺ mutations. In contrast, only 1 out of 13 trp^? frameshift mutations examined was UV reversible, and the process of mutagenesis was umuC⁺-dependent, whereas a potent frameshift mutagen, ICR191, effectively induced Trp⁺ mutations in most of the strains regardless of the umu⁺ or umuC genetic background. These results suggest that base substitutions are a major mutational type derived from the umuC⁺-dependent pathway of error-prone repair.     

Seed production of Arabidopsis thaliana under hypobaric conditions.

In the present study, we examined carbohydrate contents of Arabidopsis thaliana seeds during seed development under hypobaric conditions in order to characterize the mechanism of low pressure-induced seed damage, and to determine critical pressures for seed development under low total and/or low oxygen partial pressures. We analyzed contents of starch, sucrose, glucose, and fructose in seeds at different developmental stages at 101 kPa total pressure with 21 kPa O2 partial pressure (control conditions), and at various low pressure conditions (23 kPa Ptot/21 kPa pO2, 101 kPa Ptot/2 kPa pO2, 53 kPa Ptot/2 kPa pO2, 23 kPa Ptot/2 kPa pO2, 12 kPa Ptot/10 kPa pO2, and 12 kPa Ptot/2 kPa pO2). Our results indicate that maintaining an adequate oxygen partial pressure inside the siliques is necessary for seed production under hypobaric conditions.     

Structural alteration of linear plasmids encoding the genes for polychlorinated biphenyl degradation in Rhodococcus strain RHA1

Polychlorinated biphenyl (PCB) tolerant derivatives of a strong PCB degrader, Rhodococcus strain RHA1, were selected after growth in the presence of 100 g/ml PCBs. Some of the derivatives did not grow on biphenyl but accumulated a yellow coloured metabolite suggesting a defect in the meta-ring-cleavage compound hydrolase step encoded by the bphD gene. Other derivatives failed to grow on biphenyl and exhibited little PCB transformation activity suggesting a defect in the initial ring-hydroxylation dioxygenase step encoded by the bphA gene. These organisms had a structural alteration in the linear plasmids coding for the bph genes in RHA1, which included the bph gene deletion. When a bphD containing plasmid was introduced into a tolerant derivative, RCD1, which was shown to have a bphD deletion, the defect in the growth on biphenyl of RCD1 was overcome. The bph gene deletion seems to play a key role in these tolerant derivatives thereby suggesting that the toxic metabolic intermediate would be a main cause of the growth inhibition of RHA1 in the presence of high concentration PCBs.