The genus Gymnoascus Baranetzky

Summary The genusGymnoascus Baranetzky is monographed and found to include five valid species including one previously recognized species,G. reessii, one new combination,G. johnstoni, two new species,G. longitrichus andG. corniculatus, and a species originally described as aGymnoascus but included inMyxotrichum since 1893,G. uncinatus. Twenty species previously described as belonging toGymnoascus are excluded from the genus or are considered as doubtful representatives.Supported in part by Botany Department Research Grant # 1344, University of California, Los Angeles, California.     

PRIMARY CUTANEOUS COCCIDIOIDOMYCOSIS—The Criteria for Diagnosis and a Report of a Case

Study was made of a case of coccidioidomycosis known to have resulted from primary inoculation of the organisms into the skin. Clinical observations and laboratory data were obtained at the time of clinical illness and for a period of five years thereafter. From the information thus obtained and correlation of it with what already was known of coccidioidomycosis, it was concluded that the disease originates very rarely as the result of primary cutaneous inoculation. In most instances lesions suspected to be of this type have actually resulted by dissemination of the organisms to the skin from a previously unrecognized pulmonary focus.Primary cutaneous coccidioidomycotic lesions closely resemble the primary cutaneous lesions (chancres) in other infectious granulomata, such as syphilis, tuberculosis and sporotrichosis. Spontaneous involution should occur within three months and then there should be immunity to reinfection in all but one or two per thousand instances.From these observations certain criteria were evolved by which to determine in a case of coccidioidomycosis with cutaneous manifestations whether or not the infecting organism entered through the skin.     

Genome sequencing on both strands: the Janus strategy.

The design of large scale DNA sequencing projects such as genome analysis demands a new approach to sequencing strategy, since neither a purely random nor a purely directed method is satisfactory. We have developed a strategy that combines these two methods in a way that preserves the advantages of both while avoiding their particular limitations. Computer simulations showed that a specific balance of random and directed sequencing was required for the most efficient strategy, termed the Janus strategy, which has been used in the Escherichia coli genome sequencing project. This approach depended on obtaining sequence easily from either strand of a cloned insert, and was facilitated by inversion of the insert in the engineered M13 vector Janus, by site-specific recombination. The inversion was accomplished simply by growth on the appropriate host strain, when the DNA strand incorporated into the new single stranded phage was complementary to that in the original phage, and was sequenced by the same simple protocol as the first strand.     

The onset of DNA synthesis and its relation to morphogenetic events of the pronuclei in activated eggs of the sea urchin, Arbacia punctulata

Experiments were carried out in order to investigate the onset of DNA synthesis and its possible relation to pronuclear morphogenesis prior to, during, and following pronuclear fusion in the sea urchin, Arbacia punctulata. Analysis of the acid-soluble radioactivity of zygotes continuously incubated in tritiated thymidine (³H-TdR) at 22°C demonstrated the production of thymidine triphosphate prior to and during pronuclear migration (5–10 min post-insemination) which continued to increase until prophase (about 45 min post-insemination). DNA synthesis was initiated subsequent to pronuclear fusion, i.e., 15–20 min post-insemination. Little or no cytoplasmic label was detected during fertilization. Silver grains were first detected over the zygote nucleus in sections prepared for light and electron microscopic radioautography from zygotes fixed at 18 min post-insemination. Incubation of Arbacia zygotes at 12°C dramatically slowed development but did not alter the temporal relation between pronuclear fusion and DNA synthesis. Radioautographs of polyspermic zygotes demonstrated that unfused male pronuclei were able to synthesize DNA and substantiate the claim that pronuclear fusion is not required for the initiation of DNA synthesis. Analysis of autoradiographs of artificially activated eggs also lead to the same conclusion. Uptake of ³H-TdR or ³H-bromodeoxyuridine was not found in spermatozoa incorporated into polyspermic oocytes regardless of whether or not they had initiated or developed into male pronuclei. It is concluded that the relation between DNA synthesis and pronuclear fusion is not close or a direct one, i.e., pronuclear fusion does not appear to be a prerequisite for the onset of DNA synthesis in Arbacia.     

High-affinity angiotensin receptors in rat adrenal medulla

Angiotensin II receptors have been quantitated in single rat adrenal medullas by incubation of tissue sections with 125I-[Sar1]-AII, autoradiography with exposure to 3H-sensitive Ultrofilm, computerized densitometry and comparison with 125I-labelled standards. Rat adrenal medulla contains a single class of high affinity AII receptors with a Ka of 0.84 +/- 0.02 X 10(9) M-1 and a Bmax of 3259 +/- 502 fmol/mg protein, one of the highest densities in AII receptors found in rat tissues. These observations provide evidence for a local site of action of AII in the release of adrenal medullary catecholamines.     

Resistance to mutagenesis of cells biochemically transformed by herpesvirus DNA fragments

LM(TK-) mouse fibroblast cells that were biochemically transformed to the dThd kinase-positive phenotype by restriction nuclease fragments of herpes simplex virus or marmoset herpesvirus DNA, all of which contained the virus dThd kinase coding region, or by HeLa S3 DNA were more resistant to mutagenesis by N-methyl-N'-nitro-N-nitrosoguanidine or 5-bromodeoxyuridine than were dThd kinase-positive LM and LM(TK-) cells. Measurements of dNTP pool sizes did not reveal relative imbalances for representative cell lines under several conditions of growth.