Praziquantel-induced secretion of proteolytic enzyme from Schistosoma mansoni cercariae

The effect of praziquantel (PZQ) on secretion of proteolytic enzyme by Schistosoma mansoni cercariae was examined using an azocoll assay. The cercariae secreted proteolytic enzyme in various concentrations of PZQ (0.1, 1, and 10 micrograms/ml), but secretion of enzyme was highest at the lowest concentration. PZQ-induced secretion of proteolytic enzyme was partially inhibited by treatment with verapamil and ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetra-acetic acid but not by calmodulin antagonist W-7 and protein kinase C inhibitor H-7.     

Localization of the antigen for the monoclonal antibody ②9F11-B-E4 interspecific cross-reaction in the freshwater triclads

The localization of the antigen for monoclonal antibody 9F11-B-E₄ was clarified by immuno-electron microscopy. The antigens were localized on the mitochondria and Golgi bodies in the male germ cells and on the secretory granules of various glands cells in the penis bulb and subepidermal parenchymal tissue of Phagocata vivida. The results of the interspecific cross-reaction tests with seven other freshwater triclads showed that these secretory granules are species-specific. A positive interspecific reaction was showed with Dugesia (family Dugesiidae), but not with Polycelis within the same family Planariidae which suggests the position of Phagocata within the Planariidae needs to be reassesed.     

Oxidation and reduction of plastoquinone by photosynthetic and respiratory electron transport in a cyanobacterium Synechococcus sp.

The I-D dip, an early transient of the fluorescence induction, was examined as a means to monitor redox changes of plastoquinone in cells of a cyanobacterium, Synechococcus sp. That the occurrence of the dip depends upon the reduced state of the plastoquinone pool was indicated by observations that 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone and 3-(3,4-dichlorophenyl)-1,1-dimethylurea did not affect the initial rise to I but abolished the subsequent decline from I to D and that illumination of the cells with light 1, prior to fluorescence measurements, eliminated the transient. The I-D dip was prominent in freshly harvested cells containing abundant endogenous substrates, disappeared slowly as the cells were starved by aeration but reappeared on addition of fructose to the starved cells in the dark. The dip that had been induced by a brief illumination of the starved cells with light 2 was rapidly diminished in the dark and KCN inhibited the dark decay of the transient. The results indicate that plastoquinone is reduced with endogenous as well as exogenous substrates and oxidized by a KCN-sensitive oxidase in the dark, thus providing strong support for the view that plastoquinone of photosynthetic electron transport also functions in respiration. In addition, the occurrence of a cyclic pathway of electrons from Photosystem I to plastoquinone, possibly via ferredoxin or NADP, was suggested. Several lines of evidence indicate that, under a strong light 2, Photosystem I-dependent oxidation of plastoquinone predominates over Photosystem II-dependent reduction of the quinone in the cyanobacterium which contains Photosystem I more abundantly than Photosystem II.     

Ejaculations induced by p-chloroamphetamine (PCA) in rats, hamsters and mice.

The ejaculatory response induced by p-chloroamphetamine (PCA) in male rats, hamsters and mice was observed during 2 hours after the injection. The animals were treated intraperitoneally with PCA at doses ranging from 0.78125 to 160 mg/kg. The ED50 (effective dose in 50% of animals) values of PCA for the initiation of ejaculation in rats and hamsters were 1.3397 (1.0732-1.6725) and 0.1105 (0.0802-0.1522) mg/kg, respectively. On the other hand, no ejaculation was observed in any mice at any doses examined. So we concluded that there are species differences in the ejaculatory response, induced by PCA, among rats, hamsters and mice.     

Pre- and post-implantation losses of embryos in aging female IVCS mice

Mated female mice of the IVCS strain, aged 90 (control group), 180, 210, 240, 270, 300, 330, 360 and 420 days old, were studied for pre- and post-implantation loss of embryos. The percentage of pre-implantation loss in mice aged 90 to 210 days was 1.7/11.8 (14.4%) to 2.7/11.7 (23.1%). In mice aged 240 to 300 days it increased significantly as compared to the controls (46.5-90.2% versus 14.4%). It reached 100% in 300-days-old mice. The post-implantation loss of embryos and/or fetuses in mice aged 90 to 240 days was 1.0/10.2 (9.8%) to 2.5/9.0 (27.8%). In mice aged 270 to 300 days it increased significantly compared to the controls (100% versus 9.8%). The decrease in reproductive activity appeared first in a decrease in litter size, followed by a decrease in the number of blastocyst and implantation sites, and finally by anovulation during the process of aging in IVCS mice.     

ATP-dependent strontium uptake by basolateral membrane vesicles from rat renal cortex in the absence or presence of calcium

ATP-dependent Sr²⁺ transport was examined in vitro using basolateral membrane (BLM) vesicles isolated from rat renal cortex to clarify the discrimination mechanisms between strontium (Sr) and calcium (Ca) in renal tubules during reabsorption. ATP-dependent Sr²⁺ uptake and Ca²⁺ uptake were observed in renal BLM vesicles and were inhibited by vanadate. Hill plots indicate similar kinetic behavior for Ca²⁺ and Sr²⁺ uptake. The apparentK _m andV _max of ATP-dependent Sr²⁺ uptake were both higher than those for Ca²⁺ uptake. ATP-dependent Sr²⁺ uptake by BLM vesicles diminished in the presence of 0.1 μM Ca²⁺ and was more markedly inhibited by 1 μM Ca²⁺. Hill plots of Sr²⁺ uptake data with and without 0.1 μM Ca²⁺ showed that the cooperative behavior of Sr²⁺ uptake was not changed by Ca²⁺. In the presence of 0.1 μM Ca²⁺, the affinity of the transport system for Sr²⁺ and the velocity of Sr²⁺ uptake in the BLM were both decreased. However, the rate of Ca²⁺ uptake was not diminished by Sr²⁺ concentrations of <1.6 μM. These results suggest that Ca²⁺ is preferentially transported in the renal cortex BLM when Ca²⁺ and Sr²⁺ are present at the same time.     

Effects of chitin/chitosan and their oligomers/monomers on release of type I collagenase from fibroblasts

The effects of chitin/chitosan and their oligomers/monomers on the release of type I collagenase (MMP-1) from fibroblasts were evaluated using adult (adFB) and neonatal human fibroblasts (neFB) by a immunological assay. Release of MMP-1 from adFB increased significantly or tended to increase for all samples, while there was no significant change in MMP-1 levels with neFB. Because the oligomers and monomers of chitin and chitosan influenced MMP-1 activity, it was suggested that the elevated MMP-1 activity would continue until biodegradation of chitin and chitosan was complete.     

Correction to: Comparative analysis of sperm motility in liquid and seminal coagulum portions between Bornean orangutan (Pongo pygmaeus) and chimpanzee (Pan troglodytes)

Primates - In the original publication of the article, the coauthor “Takashi Hayakawa” was wrongly assigned as co-corresponding author.