Mycolic acids from Rhodococcus, Gordonia, and Dietzia

The mycolic acids from 11 species of Rhodococcus, seven species of Gordonia, and one species of Dietzia were analyzed using capillary gas chromatography and mass spectrometry (GLC/MS). All strains tested in this study were divided into three groups according to the degree of double bonds and the average carbon number (Av.Nc.) of their mycolic acids. The genus Gordonia belongs to the first group possessing an Av.Nc. in the upper 50s and 60s with 0 to 5 double bonds. Some Rhodococcus species possessed Av.Nc. in the 40s with a variety of distributions of polyunsaturated fatty acids from 0 to 4. The rest of the Rhodococcus species and the genus Dietzia possessed Av.Nc. in the 30s with saturated fatty acids. We previously reported on Nocardia strains whose Av.Nc. were in the 50s. Considering the identification of mycolic acid-containing Actinomycetales at the generic level, the Av.Nc. proved to be useful as a means of differentiating the genera Rhodococcus, Gordonia and Nocardia. The genus Dietzia was found to have its own characteristic constitution of mycolic acid molecular species. The mycolic acids from D. maris 58001T were characterized by an almost equal amount of constituents of even- and odd-numbered carbon chains, whereas the major components of mycolic acids in all other strains had even-numbered carbon chains. Another characteristic of Dietzia was some even-numbered mycolic acids which contained odd-numbered straight chains with odd-numbered alpha-branches. These characteristics indicated that Dietzia might possess a novel fatty acid biosynthesis system.     

Rhodotorulic acid from species of Leucosporidium, Rhodosporidium, Rhodotorula, Sporidiobolus, and Sporobolomyces, and a new alanine-containing ferrichrome from Cryptococcus melibiosum

An examination of 142 strains within 19 genera of yeasts and yeastlike organisms for formation of hydroxamic acids in low-iron culture showed production of hydroxamates by two unclassified strains and by 52 strains among the genera Aessosporon (3 of 3 strains), Cryptococcus (1 of 43), Leucosporidium (3 of 11), Rhodosporidium (4 of 4), Rhodotorula (27 of 39), Sporidiobolus (2 of 2), and Sporobolomyces (12 of 13). Crystalline rhodotorulic acid was isolated in amounts sufficient to account for most or all of the measured hydroxamate in culture supernatants of 16 strains representative of the five last-mentioned hydroxamate-producing genera. A new alanine-containing ferrichrome was isolated from one strain of Cryptococcus melibiosum. Rhodotorulic acid was a major metabolic product of many of the positive strains when grown in low-iron media, and iron was shown to repress its synthesis and excretion into the culture medium. The taxonomic significance of production of hydroxamic acids is described in connection with the position of these yeast species in the subclass Heterobasidiomycetidae.     

Anostraca,Conchostraca, Cladocera and Copepoda from Tunisia

In samples from 62 localities in Tunisia and La Calla area in N.E. Algeria, 56 species of Entomostraca were found. More than half of these are widespread and give little insight into the origin of the regional fauna. A few are endemic to the area and three groups are of relictual nature. The first one consists of northern species, some of which are known to have reached the central Sahara. It is argued that their populations have an estimated age of about 5–6000 yrs. At first sight, the second and more numerous group of species, the Ethiopian relicts, should be older. However, until historical times pathways around the Sahara may have functioned. One was along the Atlantic coast; a second and older one was via the Nile. The second possibility is almost a certainty, since a third group of relicts, the Oriental one, has migrated into the central Sahara as far as (and therefore probably together with) the northern relicts. This group must have come via the Nile Delta and the Libyan desert. If that pathway has also been used by Ethiopian species, all three groups of relicts are of the same age. In our Tunisian collection, only one Oriental element is represented.From a taxonomical point of view, morphological differences between the Chydorids Alona rectangula Sars and Alona elegans Kurz are sorted out and illustrated. Alona rectangula is best regarded as a superspecies. Hybridisation with A. elegans appears possible.Contribution n° 23 from project Limnology of the Sahara, under Contract n° 2.0009/75 with the Fonds voor Kollektief Fundamenteel Onderzoek, Belgium     

Ribosomes, Polyribosomes, and Deoxyribonucleic Acid from Thermophilic, Mesophilic, and Psychrophilic Clostridia

Analysis of deoxyribonucleic acid (DNA) from four species of Clostridium, including two thermophiles, a mesophile, and a psychrophile, revealed no obvious relationship between growth temperature and DNA base composition. The melting temperatures (T(m)) of the DNA from the four species varied no more among the thermophilic, mesophilic, and psychrophilic species than among many related mesophilic species. Characterization of ribosomes from the clostridia by means of optical rotatory dispersion yielded similar spectra in common with other unrelated organisms. Only small differences were noted in the base composition of ribosomal ribonucleic acid (RNA) and in the amino acid composition of ribosomal proteins, including half-cystine content, as determined by cysteic acid analysis, and accessible sulfhydryl groups, as determined by titration with dithiobis (2-nitrobenzoic acid). Except for the two thermophiles, the ribosomal protein electrophoretic patterns were dissimilar. No unusual thermal stability was manifested in the T(m) values of thermophile ribosomal RNA. However, thermophile ribosome T(m) values (69 C) were higher than were mesophile and psychrophile T(m) values (64 C). Ribosomes from the four clostridial species were also examined in regard to the effect of heat on their functional integrity, measured by their activity in poly U-directed (14)C-phenylaline incorporation, and their gross physical integrity, measured by sucrose gradient analysis. The T(d, 5) values (temperature which produces 50% inactivation after 5 min) was found to be 70 and 72 C for the two thermophiles C. tartarivorum and C. thermosaccharolyticum, respectively; 57 C for a mesophile, C. pasteurianum; and 53 C for a psychrophile, Clostridium sp. strain 69. At 55 C, little effect was seen on the thermophile ribosomes, but the mesophile ribosomes lost 90% of their activity in 1 hr, and psychrophile ribosomes lost 100% of their activity within 10 min. According to sucrose gradient profiles, heating at 55 C results in dissociation of mesophile ribosomes and aggregation of psychrophile ribosomes. Thermophile S-100 fractions were also more thermostable than were mesophile or psychrophile S-100 fractions. The T(d, 5) values were 69 C for C. tartarivorum and C. thermosaccharolyticum S-100 and 41 C for C. pasteurianum and Clostridium sp. strain 69 S-100. The effect of heat on the endogenous incorporation of (14)C-valine by polysomes was also examined. In the case of thermophile polysomes, the extent of incorporation at 55 and 37 C was about equal. In the case of mesophile and psychrophile polysomes, the extent at 55 C was 44 and 39%, respectively, of the value at 37 C. The initial rates of incorporation in all four cases were greater at 55 C than at 37 C.     

Hybrid 80S monomers formed from subunits of ribosomes from protozoa,fungi, plants,and mammals

Free 80S ribosomes of eukaryotic organisms are dissociated by KCl (0.8–1.0 m) in the presence of 2-mercaptoethanol and magnesium ions (10–15mm); the large and small subunits so formed can be recombined to yield 80S monomers. We have now studied the ability of ribosomal subunits from protozoa (Tetrahymena pyriformis), fungi (Allomyces arbuscula, Saccharomyces cerevisiae), plants (pea, wheat), and mammals (rat, mouse, rabbit) to combine to form hybrid ribosomes. In general, both subunits of the species studied participate in the formation of hybrid particles, with the exception of the 60S subunit of Tetrahymena, which does not combine with the small subunit of fungal, plant, or mammalian ribosomes. The interaction of subunits from rat and Tetrahymena ribosomes has been visualized by an electron microscope study of negatively stained preparations. The base sequences of the ribosomal RNAs of these organisms have been compared to those of Saccharomyces by nucleic acid hybridization-competition.This work was supported by a fellowship #PF-529 from the American Cancer Society and by United States Public Health Service, National Institutes of Health grant GM 12449.     

Altitude, radiation, and mortality from cancer and heart disease

The variation in background radiation levels is an important source of information for estimating human risks associated with low-level exposure to ionizing radiation. Several studies conducted in the United States, correlating mortality rates for cancer with estimated background radiation levels, found an unexpected inverse relationship. Such results have been interpreted as suggesting that low levels of ionizing radiation may actually confer some benefit. An environmental factor strongly correlated with background radiation is altitude. Since there are important physiological adaptations associated with breathing thinner air, such changes may themselves influence risk. We therefore fit models that simultaneously incorporated altitude and background radiation as predictors of mortality. The negative correlations with background radiation seen for mortality from arteriosclerotic heart disease and cancers of the lung, the intestine, and the breast disappeared or became positive once altitude was included in the models. By contrast, the significant negative correlations with altitude persisted with adjustment for radiation. Interpretation of these results is problematic, but recent evidence implicating reactive forms of oxygen in carcinogenesis and atherosclerosis may be relevant. We conclude that the cancer correlational studies carried out in the United States using vital statistics data do not in themselves demonstrate a lack of carcinogenic effect of low radiation levels, and that reduced oxygen pressure of inspired air may be protective against certain causes of death.     

RNA-Catalyzed CoA, NAD, and FAD synthesis from phosphopantetheine, NMN, and FMN

A novel in vitro selection method was developed to isolate RNA sequences with coenzyme-synthesizing activities. We used size-heterogeneous libraries containing randomized ribonucleotide sequences of four different lengths (30N, 60N, 100N, and 140N), all with 5'-ATP initiation. Two RNAs, CoES7 (30N) and CoES21 (60N), are able to catalyze the synthesis of three common coenzymes, CoA, NAD, and FAD, from their precursors, 4'-phosphopantetheine, NMN, and FMN, respectively. Both ribozymes require divalent manganese for activities. The results support the availability of these coenzymes in an RNA world, and point to a chemical explanation for the complex bipartite structures of many coenzymes.     

Nitrotyrosine, dityrosine, and nitrotryptophan formation from metmyoglobin, hydrogen peroxide, and nitrite

The biological relevance of tyrosine nitration is a subject of much interest, because extensive evidence supports formation of 3-nitrotyrosine in vivo under a variety of different pathological conditions. Several reagents are likely to be responsible for nitration in vivo, among others peroxynitrite and nitrite in the presence of H(2)O(2)/peroxidases. In this work we show that also metmyoglobin and methemoglobin can nitrate free tyrosine in the presence of nitrite and H(2)O(2). The results of these studies are simulated rather well by using a scheme that comprehends all the possible reactions that can take place in the system. Thus, a good understanding of the factors that determine the yields is achieved. Finally, we demonstrate that the system metMb/H(2)O(2)/NO(2)(-) can also lead to the nitration of tryptophan and produces, in particular, 6-, 4-, and 5-nitrotryptophan.     

Derivation and characterisation of hESC lines from supernumerary embryos, experience from Odense, Denmark

The derivation and characterisation of human embryonic stem cells provides a source of pluripotent stem cells with potential for clinical applications. Utilising locally sourced embryos from two IVF clinics, we derived and characterised five new cell lines for use in a non-clinical setting. Analysis of clinical data showed that the majority of embryos (94.5%) failed to reach the blastocyst stage of development and of all embryos, regardless of developmental status, 248 embryos were needed to create one stem cell line. From the number of embryos (69) which developed to the blastocyst stage 8.7% developed into cell lines. Using outgrowth of the whole blastocyst, we derived five new, unreported cell lines in Odense, Denmark between 2005 and 2006. Characterisation was carried out using RT-PCR, staining, karyotyping, EB formation and teratoma formation. The KMEB hESC lines will, in the future, be made available through the UK Stem Cell Bank (http://www.ukstemcellbank.org.uk/).     

Fossil sedges, macroplants, and roots from Olduvai Gorge, Tanzania

A variety of macroplants has been recorded and collected from the eastern paleolake margin of Olduvai Gorge, Tanzania, from Upper Bed I and Lower Bed II, dated at ∼1.7-1.85 Ma. The plant groups represented are sedges, grasses, and woody and herbaceous dicotyledons. Most of these plants are fragmented, but the roots are in situ. The modes and quality of preservation, however, are very variable. Silicification is the dominant type of preservation; it ranges from high quality faithful replacement of cells resulting in silicified wood and sedge culms that are identifiable on the basis of their internal anatomy, to poor quality biotubes lacking internal anatomy or external features that prevent assignment to a specific plant or invertebrate origin. In between this range are silicified roots and grass culms identified by their external anatomy, and leaf and stem impressions. Interpretation of the paleoecology is limited by the quality of preservation. The in situ root horizons are useful for recognizing paleo-surfaces. The best quality preservation where internal anatomy is preserved occurs at HWK E and MCK, localities that are in the middle of the fault compartments so the vegetation can be reconstructed for these sites. Some sedge culms are described, illustrated, and identified as possible species of Cyperus, Fuirena, and Schoenoplectus.     

Conodurine,conoduramine, and ervahanine derivatives from Tabernaemontana corymbosa

Four bisindole alkaloids, viz., 19'(S)-hydroxyconodurine, conodurinine, 19'(S)-hydroxyconoduramine, and 19'(S)-hydroxyervahanine A, in addition to conodurine and ervahanine A, were obtained from the leaf and stem-bark extracts of Tabernaemontana corymbosa. The structures of the new alkaloids were determined using NMR and MS analysis.     

Eudesmanolides,guaianolides, germacranolides and elemanolides from Zinnia species

The investigation of six Zinnia species afforded in addition to already known compounds two eudesmanolides, five guaianolides, three germacranolides, five elemanolides and a dihydroxygeranylgeraniol. The structures were elucidated by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.