Th1 type CD4+ T cells may be a potent effector against poorly immunogenic syngeneic tumors

Biotherapy - We examined the possibility that Th1 type CD4+ T cells may be an effector against three kinds of syngeneic tumors such as highly immunogenic B16 melanoma (B16) and two poorly...     

Analysis of mushroom diversity in successional young forests and equilibrium evergreen broad-leaved forests

Eight examination stations were constructed in young red pine forests and mature evergreen broad-leaved woods. A total of 32 quadrats of 10 × 10 m each were examined for vegetation and mushroom distribution and diversity once a week for one year. A total of 9707 individual mushrooms, amounting to 1470.23 g in dry weight, were analyzed for fungal communities. The results were arranged in a sequence of succession. The mushroom diversities, expressed as Shannon's , increased constantly to the equilibrium at around 3.0 in the climax forests. The distribution of the proportion of saprophytic fungi depicted a similar curve and reached equilibrium at around 0.3. The seasonal segregation in mushroom fruiting also developed and reached equilibrium. Ecological distances between the forests were estimated from the mushroom results and were compared with those estimated from the woody plant diversities. Fungal succession took place more rapidly or was more exaggerated than that of woody plants. From these results, the fungal succession and diversity in the climax forest was discussed.     

Hemoglobin Bali (bovine): βA18(Bl)Lys → his: One of the “missing links” between βA and βB of domestic cattle exists in the Bali cattle (Bovinae,Bos banteng)

The structure of the beta chain of adult bovine hemoglobin Bali of the Bali cattle was determined and compared to those of beta A, beta B, and other beta-chain variants of domestic cattle reported previously. The lysine residue at beta A18 was substituted by histidine in beta Bali18. This change requires two base substitutions at the codon and is also found in beta B18. The beta B chain differs from the beta A chain at residue Nos. 15, 18, and 119. It was concluded that a common ancestor of the beta B and beta Bali first diverged from the beta A chain through the Lys leads to His substitution. This fact indicates that the high degree of dimorphism of the beta A and beta B chains in Indian humped cattle is a result of its hybrid origin. An evolutionary tree for the bovine hemoglobin beta-chain variants was constructed based on parsimonious evolution and homology with related species.     

Plausible function of Golgi cells in the cerebellar cortex

The function of Golgi cells in the cerebellar cortex is quantitatively examined in consideration of the nonlinear input-output characteristics and convergence and divergence numbers of cells. It is strongly suggested that the two signal paths to Golgi cells have different function. The feed-forward path will have the same function as assumed in the previous theories of the cerebellar cortex, that is, to keep the firing rate of granule cells approximately constant over considerable variation in the firing rate of mossy fibers. The feedback path will, on the other hand, have a new function which has not been assumed in the previous theories. The function is to cause oscillation of the firing rate of granule cells for stationary mossy fiber inputs. The assumption of the new function enables us to explain cerebellar function to keep stationary posture.     

Selective inhibition of prostaglandin endoperoxide thromboxane isomerase by 1-carboxyalkylimidazoles

1-Carboxyalkylimidazoles inhibited the conversion of prostaglandin H₂ to thromboxane B₂ and 12L-hydroxy-5, 8, 10- heptadecatrienoic acid by a partially purified enzyme (prostaglandin endoperoxide thromboxane isomerase) from bovine platelet microsomes. The degree of the inhibition was dependent on the length of carboxyalkyl chain. 1-Carboxyheptylimidazole was the most potent inhibitor, and an almost complete inhibition was obtained at a concentration on the order of 1 μM. The inhibition, as examined with 1-carboxyheptylimidazole, was of noncompetitive type. These 1-carboxyalkylimidazoles did not affect the formation of prostaglandin H₂ from arachidonic acid. Such a selective inhibition was also demonstrated by the reaction of bovine platelet microsomes with arachidonic acid in the presence of 1-carboxyheptylimidazole, resulting in the accumulation of prostaglandin H₂ as an intermediate. Furthermore, a series of 1-alkylimidazoles with no carboxyl group also inhibited the isomerase at higher concentrations. However, the inhibition was not specific for the isomerase; namely, the prostaglandin H₂ formation from arachidonic acid was also affected.     

The finding and partial purification and characterization of thymone C

A fraction, isolated from bovine thymus by sequences of $\text{ca.}$ ten steps of extractions, gel filtrations, ion exchange chromatography, etc., stimulated the synthesis of both cAMP and cGMP at a level of 100 μg/ml. Thymone A stimulated cAMP, but is chromatographically remote from the fraction. Essentially pure thymone B, which stimulates cGMP, did not stimulate cAMP even at a high level of 100 μg/ml. The presence of thymone B in this fraction is supported by TLC data. This fraction also stimulated the mixed lymphocyte reaction. The cAMP-stimulating entity is designated thymone C until it is characterized and related to or differentiated from products of other investigators.     

New sweet diterpene glucosides from Stevia rebaudiana

From the leaves of Stevia rebaudiana, two new sweet glucosides, rebaudiosides A and B, were isolated besides the known glucosides, stevioside and steviolbioside. On the basis of IR, MS, ¹H and ¹³C NMR as well as chemical evidences, the structure of rebaudioside B was assigned as 13-O-[β-glucosyl(1-2)-β-glucosyl(1-3)]-β-glucosyl-steviol and rebaudioside A was formulated as its β-glucosyl ester.     

Differentiation of restriction sites in ribosomal DNA in the genusApodemus

Southern blot analysis of ribosomal DNA (rDNA) from seven species ofApodemus was carried out in order to examine the genetic relationships between the species. Analysis of heterogeneity in rDNA spacers inA. sylvaticus, A. flavicollis, A. semotus, A. agrarius, A. argenteus, A. speciosus, andA. peninsulae, using 13 different restriction enzymes and cloned mouse rDNA probes, revealed that the families of rDNA in these species can be characterized by restriction maps which show the major constituents of rDNA repeating units (repetypes). Based on differences in the arrangement of restriction sites, sequence divergence among the different major repetypes was estimated. Among the seven species ofApodemus examined, the major repetypes ofA. flavicollis andA. sylvaticus were the most closely related, having only 1.0% sequence divergence. These repetypes and those of the remaining five species differ substantially from one another, with 4.3–8.5% divergence.This study was supported in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, Japan.