Value of chemical mixture in multiple supralethal X-irradiation of mice

A chemical mixture containing 25 Amoles of MEA, 7 pmoles of AET, and 2 micromoles of 5-HT was found to be of significant value in protecting mice against repeated exposures of 800 R, 1100 R, or 1400 R given at intervals of 28 days. Dose-reduction factors of 2.17, 2.18, 1.95, 2.14, and 1.58 were obtained for the first five exposures. Following the first exposure there was no chemical mortality. The beneficial value of this mixture, however, was limited by the incidence of chemical toxicity which was more prevalent in mice with higher cumulative doses of radiation.     

Nematodes of the family Heligmonellidae (Trichostrongyloidea) collected from rodents of the Ryukyu archipelago and Taiwan

Six species of the family Heligmonellidae (Nematoda: Trichostrongyloidea), including 3 new species, are recorded from rodents of the subfamily Murinae in the Ryukyu Archipelago and Taiwan. Heligmonoides ikeharai n. sp. from Tokudaia osimensis muenninki on Mt. Yonaha, Okinawa Island, is characterized by extremely long spicules and hypertrophied ridges in the prevulval region. Heligmonoides taiwanensis n. sp. from Apodemus draco on Mt. Alishan, Taiwan, is distinguished from other members of the genus in having a markedly asymmetrical bursa and stout bursal rays. Heligmonoides alishanensis n. sp. from Niviventer confucianus on Mt. Alishan differs from the allied forms in lacking hypertrophied ridges at the level of the middle of the spicules and in having longer spicules and a smaller body. Nippostrongylus sp. from N. confucianus on Mt. Alishan resembles Nippostrongylus brasiliensis but is distinguishable in that the externolateral ray is almost the same length as the lateroventral ray in the left lobe, and the fused tips of the spicules are thin and straight. Heligmonoides ryukyensis from Mus caroli and Orientostrongylus tenorai from Bandicota indica are first recorded from Taiwan. Heligmonellid nematodes parasitic in wild rodents in these areas are considered to have been introduced with their hosts from the mainlands of China and Japan through land connections in the Pleistocene.     

Two new nematodes from the Iriomote cat, Prionailurus iriomotensis, from Okinawa: Uncinaria (Uncinaria) maya n. sp. (Ancylostomatoidea) and Molineus springsmithi yayeyamanus n. subsp. (Trichostrongyloidea)

Uncinaria (Uncinaria) maya n. sp. (Nematoda: Ancylostomatidae) and Molineus springsmithi yayeyamanus n. subsp. (Nematoda: Molineidae) are described from the Iriomote cat, Prionailurus iriomotensis, on Iriomote Island, Okinawa, Japan. Uncinaria (U.) maya resembles Uncinaria (Uncinaria) felidis Maplestone, 1939, from Prionailurus bengalensis of India but is distinguished in that the body is much smaller, the ventral rays are set closely with the lateral rays, and the externolateral ray is much shorter than other laterals. Molineus springsmithi yayeyamanus differs from Molineus springsmithi springsmithi Inglis and Ogden, 1965, from Prionailurus bengalensis horsfieldi of East Nepal in that the body is much longer, whereas the esophagus is somewhat shorter and the spicules are divided more distally. Presence of the closely related nematodes in both the Iriomote cat and P. bengalensis suggests a close evolutionary relationship of the 2 hosts.     

SFA-1, a novel cellular gene induced by human T-cell leukemia virus type 1, is a member of the transmembrane 4 superfamily.

A novel cellular gene termed SFA-1 was isolated by differential hybridization of a cDNA library, using probes obtained from an adult T-cell leukemia cell line in comparison with probes obtained from normal CD4+ T cells and the MOLT-4 cell line. The mRNA of the SFA-1 gene is approximately 1.6 kb in size and encodes a protein of 253 amino acids, containing four putative transmembrane domains, a number of cysteine residues, and one potential N-glycosylation site in a major hydrophilic region between the third and fourth transmembrane domains. Expression of the SFA-1 gene was either absent or present at a low level in lymphoid cells but was up-regulated after transformation by human T-cell leukemia virus type 1 and transactivated by Tax. SFA-1 was broadly expressed in many human cell types and conserved in different species. Computer-aided comparison showed that SFA-1 had significant sequence homology and common structural features with members of the transmembrane 4 superfamily. SFA-1 antigen was detected as a 29-kDa membrane protein by immunoblotting, using anti-SFA-1 monoclonal antibody.     

Promotion of Cocklebur Seed Germination by Allyl, Sulfur and Cyanogenic Compounds

The effects of allyl, sulfur and cyanogenic compounds on thegermination of upper cocklebur (Xanthium pennsylvanicum Wallr.)seeds were examined. Mercaptoethanol and methylmercaptan aswell as KCN, substrates for rßcyanoalanine synthase(CAS), and H₂S and thiocyanate, the products of the CAS catalyzingreaction, were effective in promoting germination, suggestingthe involvement of CAS in germination. Most of allyl compounds, especially allylthiourea, as well asethylene which activated CAS [Hasegawa et al. (1994) Physiol.Plant. 91: 141], promoted the germination in an abnormal typewhich occurred by the predominant growth of cotyledons as didC₂H₄ [Katoh and Esashi (1975) Plant Cell Physiol. 16: 687].However, they failed to activate CAS unlike ethylene, and toliberate free ethylene during an incubation period. It was thuspossible that an C₂H₄-like double bond within allyl compoundscan act to promote seed germination. (Received June 10, 1996; Accepted August 21, 1996)     

Phylogenetic relationships among eutherian orders estimated from inferred sequences of mitochondrial proteins: Instability of a tree based on a single gene

The phylogenetic relationships among Primates (human), Artiodactyla (cow), Cetacea (whale), Carnivora (seal), and Rodentia (mouse and rat) were estimated from the inferred amino acid sequences of the mitochondrial genomes using Marsupialia (opossum), Aves (chicken), and Amphibia (Xenopus) as an outgroup. The overall evidence of the maximum likelihood analysis suggests that Rodentia is an outgroup to the other four eutherian orders and that Cetacea and Artiodactyla form a clade with Carnivora as a sister taxon irrespective of the assumed model for amino acid substitutions. Although there remains an uncertainty concerning the relation among Artiodactyla, Cetacea, and Carnivora, the existence of a clade formed by these three orders and the outgroup status of Rodentia to the other eutherian orders seems to be firmly established. However, analyses of individual genes do not necessarily conform to this conclusion, and some of the genes reject the putatively correct tree with nearly 5% significance. Although this discrepancy can be due to convergent or parallel evolution in the specific genes, it was pointed out that, even without a particular reason, such a discrepancy can occur in 5% of the cases if the branching among the orders in question occurred within a short period. Due to uncertainty about the assumed model underlying the phylogenetic inference, this can occur even more frequently. This demonstrates the importance of analyzing enough sequences to avoid the danger of concluding an erroneous tree.     

Presence of β-cyanoalanine synthase in unimbibed dry seeds and its activation by ethylene during pre-germination

Evolution of HCN from both rice ( Oryza sativa ) and cocklebur ( Xanthium pennsylvanicum ) seeds increased during a pre-germination period and preceded the evolution of (C₂H₄). These two species were adopted as the representatives of starchy and fatty seeds, respectively. Ethylene promotes seed germination of many species. However, HCN evolution declined abruptly when the radicles emerged and before the peak in C₂H₄ evolution. More-over, both rice and soybean ( Glycine max ) seeds showed some activity of β-cyanoalanine synthase (CAS, EC 4.4.1.9) even in the unimbibed dry state. The activities of CAS in the lower seed of cocklebur and in soybean seeds increased rapidly after emergence of the radicle. However, the CAS of rice seeds, with high activity in the dry state, exhibited a bimodal change, gradually decreasing until radicle emergence had occurred, but then increaing. It is thus likly that HCN evolution during initial imbibition may be derived from cyanogenic reserves and controlled by both pre-existing and subsequently-developing CAS. The exogenous application of C₂H₄ stimulated the activities of CAS in both rice and upper cocklebur seeds and reduced their cyanogen contents. Therefore, the decline of HCN evolution after germination seems to be due to the increased activities of CAS by endogenously produced C₂H₄.