Respiration and Motility in Starfish Spermatozoa at Various Times in the Breeding Season

In the spermatozoa of Asterias amurensis , patterns of changes in the respiratory rate and motility following dilution of dry sperm in sea water varied among batches and were classified into three types. The type I spermatozoa were immotile and exhibited quite low respiratory rate. Ethylenediamine tetraacetic acid made the type I spermatozoa motile and elevated their respiratory rate. The type II spermatozoa were also immotile and the respiratory rate remained quite low for about 5 min after the dilution. Thereafter, they spontaneously became motile and the respiratory rate increased. The type III spermatozoa became motile upon their dilution and exhibited high respiratory rate. Differences in the motility and respiratory rate of spermatozoa among batches probably result from degree of their maturation. In moving spermatozoa, the ADP and AMP levels increased at the expense of ATP. 2,4-Dinitrophenol elevated the respiratory rate only in immotile spermatozoa, which showed a high ATP level and quite low ADP level, but did not made them motile. Oligomycin inhibited the respiration of both motile and immotile spermatozoa. Probably, the respiratory rate is made low by a shortage of ADP in immotile spermatozoa and is enhanced by ADP production due to the initiation of their movement.     

Pneumocystis carinii: Freeze-fracture study of stages of the organism

The morphology and life cycle of Pneumocystis carinii were studied in cortico-steroid-treated rats by ultrathin section and freeze-fracture electron microscopy. The following stages of P. carinii were noted: trophic, precyst, and cyst. The crescent-shaped cysts appeared to be intermediate forms between precyst and cyst. The cell wall of the trophic stage showed membrane structures suggestive of protozoan endocytosis, whereas the surface of the precyst stage was smooth. The cell wall of the cyst lacked the specialized structural differentiation of yeasts and resembled that of Plasmodium spp. We conclude that P. carinii belongs to the Protozoa, and is presumably Rhizopoda.     

Semisynthesis and properties of some insulin analogs

The trypsin-catalyzed coupling of bovine (Boc)₂-desoctapeptide (B23-B30)-insulin with synthetic octapeptides, H-Gly-X₂-X₃-X₄-Thr-Pro-Lys(Boc)-Thr-OH (X₂ = Phe or Ala, X₃ = Phe or Ala, X₄ = Tyr or Ala), followed by deprotection and purification produced the [Ala^B24, Thr^B30]-, [Ala^B25, Thr^B30]-, and [Ala^B26, Thr^B30]-analogs of bovine insulin in yields of 32, 35, and 32%, respectively. The biological activity of these analogs decreased in the order, normal insulin ([Thr^B30]-bovine insulin) = Ala^B26-insulin > Ala^B25-insulin > Ala^B24-insulin, as assayed for receptor binding and some other biological effects, in contrast with the corresponding Leu-analogs of human insulin, in which the activity decreased in the order, normal insulin > Leu^B24-insulin > Leu^B25-insulin. The affinity to insulin antibodies greatly diminished in both Ala^B24-insulin and Leu^B24-insulin but not in the B25-substituted analogs. The CD spectra of the Leu- and the Ala-analogs were compared with those of normal insulins to show that no apparent correlation seems to exist between the decrease in biological activity and the conformational changes observed in solution. The effects of organic solvents on the peptide-bond equilibrium and on the stability of trypsin are also discussed.     

Kinetics of the oxidation of Rhus vernicifera stellacyanin by the Co(EDTA)-- ion.

A kinetic study of the oxidation of the copper(I) form of the blue copper protein stellacyanin (St(I) by Co(EDTA)-- has been performed. Observed rate constants approach a saturation limit with increasing [Co(EDTA)--] at pH 7, consistent with a mechanism involving rapid pre-equilibrium oxidant-protein complex formation followed by rate-limiting intramolecular Cu(I) to Co(III) electron transfer: Co(EDTA)-- + St(i Qp in equilibrium Co(EDTA)-- ---St(I) Co(EDTA)-- ---St(I) k2 leads to Co(EDTA)2-- ---St(II) (Qp = 149 M--1, k2 = 0.169 sec--1; 25.1 degrees, pH 7.0 mu 0.5 M (phosphate)). Activation parameters based on k2 (deltaH not equal to = 1.8 kcal/mol, deltaS not equal to = --56 cal/mol-deg) indicate that the electron transfer process is substantially nondiabatic, in marked contrast with results obtained for Co(phen) 3 3+ as the oxidant. Linear kobsd VS. [Co(EDTA)--] plots are reported for the Co(EDTA)-- oxidation of cuprous stellacyanin at pH 10 (k = 8.9 M--1 sec--1; 25.0, pH 10, mu 0.5 M (carbonate); DELTaH not equal to 11.3 kcal/mol, deltaS not equal to = -16 cal/mol-deg) and at pH 7 in the presence of excess EDTA (k = 21.2 M--1 sec--1; 25.1 degree, pH 7.0, mu 0.5 M (phosphate), [EDTA] tot = 5 X 10(--4) M; deltaH not equal to = 5.9 kcal/mol, delta S not equal to = --33 cal/mol-deg). It is concluded that Co(EDTA)-- adopts an electron transfer mechanism similar to that preferred by Co(phen)33+ under conditions where the oxidant is prevented from binding strongly to reduced stellacyanin.     

Ionic mechanism of 5-hydroxytryptamine induced hyperpolarization and inhibitory junctional potential in body wall muscle cells of Hirudo medicinalis

Five-hydroxy tryptamine (5-HT) causes a hyperpolarization and increased conductance of the leech body wall muscle cell membrane. If 5-HT is applied in the absence of the Cl^?ion, the response appears as a depolarization, whereas if 5-HT is applied in the absence of the K⁺ion, the response is a hyperpolarization. In both cases, the conductance of the muscle cell membrane is increased. Stimulation of the peripheral nerve to the body wall muscle produces a complex junctional potential in muscle cells. Exposing the muscle to d-tubocurarine (d-TC) eliminates the excitatory component (EJP) of the complex potential. The inhibitory potential (IJP) that remains has an equilibrium potential at approximately 65 m V. Furthermore, this IJP appears as a depolarization when the nerve is stimulated in the presence of d-TC and low CL^?, whereas this is not the case if the nerve is stimulated in the presence of d-TC and low K⁺. The drugs BOL-148 and cyproheptadine block the IJP's in the body wall muscle. These data are interpreted as indicating that 5'HT acts on leech body wall muscle cells by increasing the conductance to the Cl^?ion and that the IJP's caused by nerve stimulation are probably the result of 5-HT release at nerve terminals. As a final point, it has been shown that the inhibition by 5-HT of the spontaneous EJP's that occur on the leech body wall muscle results from an inhibition of central neurons and not from any direct effect on the muscle cell or on peripheral synapses.     

Mutation of Bacillus subtilis causing hyperproduction of alpha-amylase and protease, and its synergistic effect.

Mutants that had a genetic lesion increasing the production of alpha-amylase and protease simultaneously were isolated from a transformable strain of Bacillus subtilis Marburg by N-methyl-N'-nitro-N-nitrosoguanidine treatment. These mutants produced two to three times more alpha-amylase and five to 16 times more protease than their parent and were tentatively referred to as AP mutants. As this mutation seems to have occurred at a single gene of the bacterial chromosome and was not located near the alpha-amylase structural gene, the gene was designated as "pap." When pap- and amyR2 (an alpha amylase regulator gene) or pap- and ProH coexisted in the same cell, synergistic effects of the two genetic characters were observed on the alpha-amylase and protease production, respectively. Upon introduction of the pap mutation, the following phenotypic changes were observed in addition to changes in alpha-amylase and protease productivity. (i) Mutants lost the character of competence for the transformation. (ii) When cells were cultured at 30 C for 30 h, mutant cells became filament owing to the formation of chains of cells. (iii) Autolysis of cells was decreased in the mutants. When pap- was transferred to the wild strain by deoxyribonucleic acid-mediated transformation, the transformants showed all these phenotypic alterations simultaneously.     

The fine structure of ependymal cells part II: An electron microscopic study of the soft-shelled turtle paraventricular organ,with special reference to the fine structure of ependymal cells and so-called albuminous substance

Summary The present study deals with the electron microscopic observations on the softshelled turtle paraventricular organ, with special reference to the relationship of the ependymal cells and the so-called albuminous substances. It is shown that the so-called albuminous substances consist of the tips of neuronal processes extending into the ventricular lumen. They probably arise from the nerve cells lying within the hypendymal or the underlying tissue. The ependymal cells of the PVO themselves are basically similar in structure to those of any other animal.The processes observed contain two types of vesicles, namely: the clear vesicle, 500 to 1600 Å in diameter, and the cored vesicle, measuring 600 to 1500 Å in diameter, which has a distinct membrane enclosing an extremely dense core of variable sizes. The functional significance of these vesicles is discussed in relation to that of inclusions in the neurosecretory and the autonomic nerve fibers in the hypothalamus.The findings indicate that in the terminal endings of the processes a production or formation of vesicles might occur and that these vesicles might be discharged into the cerebrospinal fluid by microapocrine secretion.The author's grateful thanks are due to Prof. E. Yamada for his continuously kind guidances and due to Prof. T. Sakurai for his constant encouragement.     

Microflow system promotes acetaminophen crystal nucleation

It is known that interfaces have various impacts on crystallization from a solution. Here, we describe crystallization of acetaminophen using a microflow channel, in which two liquids meet and form a liquid–liquid interface due to laminar flow, resulting in uniform mixing of solvents on the molecular scale. In the anti‐solvent method, the microflow mixing promoted the crystallization more than bulk mixing. Furthermore, increased flow rate encouraged crystal formation, and a metastable form appeared under a certain flow condition. This means that interface management by the microchannel could be a beneficial tool for crystallization and polymorph control.