Angiostrongylus cantonensis: Development following pulmonary arterial transfers into permissive and nonpermissive hosts

The survival, growth, and egg-laying capacity of young adult Angiostrongylus cantonensis, surgically transferred from intracranial sites into pulmonary arteries, were studied. A variety of experimental animals (rats, guinea pigs, mice, and mastomys) were chosen as donor animals and as recipient hosts (rats, guinea pigs, and rabbits). These species were specifically chosen to span the spectrum of host permissiveness relative to worm development in an attempt to understand the mechanisms which underlie species-dependent resistance. Recipient animals were monitored not only for the development of parasites per se but also for antibody production and histopathologic changes. The results indicated that these procedures were technically feasible, with good worm development following intra-rat transfers, as early as 15 days after initial exposure. Studies were performed to analyze the constraints of development both on initial, i.e., prelung and subsequent i.e., postlung development. When worms were obtained from permissive species such as rat or mastomys, transfer into rats resulted in good growth and development; however, worms which developed initially in exposed mice or guinea pigs developed less well in the rat. Conversely, worms which developed initially in permissive host such as the rat, when transferred into a variety of less permissive hosts such as the guinea pig and rabbit, apparently did not survive and caused significant morbidity and mortality within the nonpermissive host. Histopathologic evaluation revealed a strong eosinophilic perivascular and peribronchiolar infiltration as well as granulomatous reactions surrounding the worms in the lungs of recipient guinea pigs and rabbits, changes not observed in the lungs of permissive rat recipients. As reaginic antibody responses were also more prominent in nonpermissive than in permissive animals, it is possible that IgE responses may be more directly related to the phenomenon of morbidity and/or permissiveness than are other aspects of immune response. In support of this contention was the finding of nearly equivalent hemagglutinating antibody production between permissive rats and nonpermissive guinea pigs and rabbits.     

Microbiological transformations of delta6a10a-tetrahydrocannabinol.

A screening program was conducted to find microorganisms that catalyze transformation reactions with cannabinoids. Three hundred fifty-eight cultures, consisting of 97 bacteria, 175 actinomycetes, and 86 molds, were incubated in media containing 0.5 mg of Delta(6a,10a)-tetrahydrocannabinol (Delta(6a,10a)-THC) per ml. After 120 h of cultivation, ethyl acetate extracts of the cultures were examined by thin-layer chromatography (TLC) for transformation products. About 18% of the cultures modified Delta(6a,10a)-THC. The ability to modify the substrate did not predominate among any particular group of microorganisms. After purification, the products from three cultures were analyzed by high-resolution mass spectrometry, 100-mHz proton magnetic resonance spectrometry, ultraviolet spectrometry, and infrared spectrometry. These spectral data indicated that a Mycobacterium sp. oxidized Delta(6a,10a)-THC to cannabinol and a diastereomeric pair of 6a-hydroxy-Delta(10,10a)-THC isomers; a Streptomyces sp. and a Bacillus sp. oxidized Delta(6a,10a)-THC to 7-keto-Delta(6a,10a)-THC and 4'-hydroxy-Delta(6a,10a)-THC, respectively. The occurrence of these products and the presence of others that have not yet been isolated or identified indicate that microbial transformation may be a useful tool for the preparation of new cannabinoids that have desirable pharmacological properties.     

Effect of piperonyl butoxide and diphenylamine on lipid peroxidation in ozonated chloroplasts

Lipid peroxide (LPO) formation was remarkable when isolatedtobacco chloroplasts were bubbled with high concentrations ofozone, though the fatty acid composition and the fractionationpattern of glycolipids and phospholipids in the chloroplastlipids changed little after ozone fumigation of the leaves.Piperonyl butoxide (PB), a potent protectant against ozone injury,strongly inhibited LPO formation in ozonated chloroplasts. PBalso prevented ozone-induced decreases in the amounts of linolenicand linoleic acids in the chloroplast lipids. These resultssuggest that PB inhibition of LPO formation may be involvedin the protective mechanism against ozone phytotoxicity. However,the mode of PB action differed on some points from that of diphenylamine,which is an antioxidant and also effective against ozone injury.The mode of PB action is discussed. ¹ Present address: The Central Research Institute, Japan Tobacco& Salt Public Corporation, Umegaoka, Midori-ku, Yokohama227, Japan. (Received July 5, 1976; )     

Orientation of mineral in bovine bone and the anisotropic mechanical properties of plexiform bone.

Angular dependent Young's modulus E phi presented by Bonfield and Grynpas [Nature 270, 453-454 (1977)] was simulated by using the distribution function of the orientation of mineral in plexiform bone introduced on the basis of an X-ray pole figure analysis (XPFA) and a small angle X-ray scattering (SAXS) results. Calculations were performed with the aid of a simple model which expresses well the geometrical characteristic of plexiform bone. Estimated angular dependent Young's modulus in terms of the distribution of mineral orientation reproduced the experimental results. The suitable aspect ratio of bone mineral for the reproduction of the empirical data was a reasonable value compared with the morphological study of bone mineral. It is concluded that the angular dependence of mechanical properties of plexiform bone is explained by the distribution of bone mineral orientation and its morphology.     

Purification and properties of an ethylene-forming enzyme from Pseudomonas syringae pv. phaseolicola PK2.

A novel ethylene-forming enzyme that catalyses the formation of ethylene from 2-oxoglutarate was purified from a cell-free extract of Pseudomonas syringae pv. phaseolicola PK2. It was purified about 2800-fold with an overall yield of 53% to a single band of protein after SDS-PAGE. The purified enzyme had a specific activity of 660 nmol ethylene min-1 (mg protein)-1. The molecular mass of the enzyme was approximately 36 kDa by gel filtration and 42 kDa by SDS-PAGE. The isoelectric point and optimum pH were 5.9 and ca. 7.0-7.5, respectively. There was no homology between the N-terminal amino acid sequence of the ethylene-forming enzyme of Ps. syringae pv. phaseolicola PK2 and the sequence of the ethylene-forming enzyme of the fungus Penicillium digitatum IFO 9372. However, the two enzymes have the following properties in common. The presence of 2-oxoglutarate, L-arginine, Fe2+ and oxygen is essential for the enzymic reaction. The enzymes are highly specific for 2-oxoglutarate as substrate and L-arginine as cofactor. EDTA, Tiron, DTNB [5,5'-dithio-bis(2-nitrobenzoate)] and hydrogen peroxide are all effective inhibitors.     

Early Determination of Developmental Fate in Presumptive Intestinal Endoderm of the Chicken Embryo

The endodermal epithelia of esophagus, proventriculus and gizzard of 6-day chicken embryos can form glands and express embryonic chicken pepsinogen (ECPg), when they are subjected to the influence of proventricular mesenchyme, while intestinal epithelium of the same age cannot respond to the inductive influence of proventricular mesenchyme. We attempted in this paper to know whether this regional difference of epithelia to respond to mesenchymal influence originates very early in development or it is established gradually in the course of development of digestive tract.
The young presumptive intestinal endoderm taken from embryos having 15–20 somites was associated and cultivated with 6-day proventricular mesenchyme. The presumptive intestinal endoderm never expressed ECPg although it formed gland-like structures. In the control explants composed of presumptive stomach endoderm and proventricular mesenchyme, glands were formed and gland cells expressed ECPg detected by immunocytochemistry and in situ hybridization.
These results indicate that the developmental fate of presumptive intestinal endoderm is determined rather strictly at very early developmental stage, and suggest that the segregation of at least two cell lineages occurs early in the development; one which can express ECPg under the influence of proventricular mesenchyme, and another one which cannot express ECPg and differentiates mainly into intestinal epithelium.     

Gray and Red Fragments of the Egg of the Ascidian Ciona savignyi: Preferential Development of Muscle Cells from Gray Fragments

The egg of the ascidian Ciona savignyi is pinkish red with brownish myoplasm that contains the putative determinants responsible for differentiation of muscle cells. When dechorionated unfertilized eggs were centrifuged at moderate speed, eggs were divided into centripetal, small gray fragments and centrifugal, large red fragments. The former contained the female pronucleus and clear cytoplasm, while most of the latter was filled with yolk granules. An antibody raised against the myoplasm of C. intestinalis eggs extensively stained the cortical region of gray fragments, while the antibody stained only small regions of the red fragments. After insemination, both fragments cleaved and gave rise to partial embryos. When development of muscle and epidermal cells in the partial embryos was examined with specific antibodies, muscle development was conspicuous in gray partial embryos, while epidermal differentiation was extensive in red partial embryos. Furthermore, when expression of markers of differentiation was examined in cleavage-arrested gray and red fragments, the number of arrested gray fragments exhibiting the muscle marker was about three-fold greater than in controls. These results suggest that putative muscle determinants are concentrated into gray fragments.     

Genes encoding peroxisomal enzymes are not necessarily assigned on the same chromosome of an n-alkane-utilizable yeast Candida tropicalis

We have resolved eight chromosomal bands from an n-alkane-assimilating yeast, Candida tropicalis pK 233, by using contour-clamped homogeneous electric field gel electrophoresis (CHEF). From the results of hybridization of DNA probes of yeast peroxisomal enzymes--catalase, acyl-CoA oxidase, carnitine acetyltransferase, isocitrate lyase, malate synthase, acetoacetyl-CoA thiolase, and 3-ketoacyl-CoA thiolase--to Southern transfers of CHEF gels, these genes were proven not necessarily to be located on the same chromosome. This fact shows that the genes encoding the enzymes tested were not distributed to be cistronic, although simultaneous and inducible synthesis of peroxisomal enzymes occurred in harmony with the proliferation of peroxisomes, suggesting that their co-ordinated expression might be mainly regulated by certain trans-acting factors.