Immunochemical characterisation of parathyroid hormone-related protein from tumor and non-tumor cells

The molecular forms of parathyroid hormone-related protein (PTHRP) in conditioned media from the BEN human lung cancer cell line, rat parathyroid cells (PT-r) and human keratinocytes were studied by gel-filtraton chromatography with assay of PTHRP by immunoassays and bioassay. Immunoreactivity (1–86 and 1–34) and bioactivity (1–34) in conditioned media eluted as a coincident major peak (approx. molecular mass 19–22 kDa) and there was evidence of amino-terminal species in the molecular mass range 10–16 kDa in BEN and keratinocyte media. Western blotting of PTHRP affinity purified by monoclonal antibodies directed at regions 1–34 or 37–67, identified a major species in all cell cytosols and media with an apparent molecular mass of 24–25 kDa, consistently slighty larger than recombinant PTHRP(1–141) (mobility of 21 kDa) which may represent an intact or native form of PTHRP. Additional amino-terminal species were identified in medium from keratinocytes (16 and 7 kDa), BEN cells (18 and 14 kDa) and PT-R cells (17 kDa), suggesting that processing occurs at the C-terminus and within the mid-region to form a range of amino-terminal fragments.     

The species composition,occurrence and temporal stability of submerged aquatic macrophyte patches along the main channel border of pool 5A,Upper Mississippi River

Species composition, relative abundance, distribution and physical habitat associations of submerged aquatic macrophytes in the main channel border (MCB) habitat of Pool 5A, Upper Mississippi River (UMR) were investigated during the summers of 1980 and 1983. The submerged aquatic macrophytes in Pool .5A MCB were a small and stable component of the river ecosystem. Submerged plants occurred primarily in small, monospecific clumps. Clumps in close proximity to each other formed plant patches. Plant patches were stable in location and number between 1980 and 1983; 82.5% of the patches first observed in 1980 were present in 1983. Submerged macrophytes covered about 10–12 ha of the 201 ha MCB in Pool 5A. Submerged plants were most common in the lower two-thirds of the pool. Ten species of aquatic macrophytes occurred on rock channel-training structures and eleven occurred on non-rock substrates in the MCB. The most common submerged plants, in order of abundance, were Vallisneria americana Michx., Heteranthra dubia Jacq., Potamogeton pectinatus L., Ceratophyllum demersum L. and Potamogeton americanus C. & S.     

Benzo[a]pyrene diol epoxide induces viral reactivation at concentrations that block DNA elongation in mammalian cells

The survival of UV-irradiated Simian virus 40 (SV40) in CV-1P African green monkey kidney cells treated with (+/-)7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BP-diol epoxide I) was studied. Enhanced survival of UV damaged SV40 was detected when CV-1P cells were treated with dose levels of BP-diol epoxide I corresponding to the exponential portion (0.33-1.11 microM) of a CV-1P cell survival curve. Dose levels of BP-diol epoxide I corresponding to the shoulder region (less than or equal to 0.16 microM) of a CV-1P survival curve did not induce viral reactivation. The shoulder region concentrations of BP-diol epoxide I selectively inhibited DNA initiation while the concentrations on the exponential portion of the curve preferentially inhibited DNA elongation. It was shown in a time course of enhanced viral survival at 0.66 microM BP-diol epoxide I that the reactivation response was fully induced by 24 h. In conclusion, the viral reactivation response was associated with concentrations of BP-diol epoxide I which induced lethal damage and preferentially inhibited DNA elongation.     

Microcalorimetry studies of energy changes during the growth of Klebsiella aerogenes in simple salts/glucose media: growth in phosphate-limited medium

The power-time traces for cells of Klebsiella aerogenes grown in phosphate-limited media were unlike those for cells grown in phosphate-sufficient media. At a phosphate concentration of 18 mumol dm-3 three phases of growth were recognized: the exponential growth phase during which phosphate became exhausted; a slower growth phase to the exhaustion of glucose, and a period of minimal growth when acetate, formed as secondary metabolite, was metabolized. At a concentration of 40 mumol dm-3 only two phases were identified. From the measured values of biomass, carbon dioxide output, glucose and acetate, mass and energy balances were established for each phase of growth and for overall growth. The results are discussed in terms of the energy stored as biomass, that wasted as heat and that required for maintenance and biosynthetic processes when the cells are grown under normal and stressful conditions.     

The Myxococcus xanthus rfbABC operon encodes an ATP-binding cassette transporter homolog required for O-antigen biosynthesis and multicellular development.

A wild-type sasA locus is critical for Myxococcus xanthus multicellular development. Mutations in the sasA locus cause defective fruiting body formation, reduce sporulation, and restore developmental expression of the early A-signal-dependent gene 4521 in the absence of A signal. The wild-type sasA locus has been located on a 14-kb cloned fragment of the M. xanthus chromosome. The nucleotide sequence of a 7-kb region containing the complete sasA locus was determined. Three open reading frames encoded by the genes, designated rfbA, B and C were identified. The deduced amino acid sequences of rfbA and rfbB show identity to the integral membrane domains and ATPase domains, respectively, of the ATP-binding cassette (ABC) transporter family. The highest identities are to a set of predicted ABC transporters required for the biosynthesis of lipopolysaccharide O-antigen in certain gram-negative bacteria. The rfbC gene encodes a predicted protein of 1,276 amino acids. This predicted protein contains a region of 358 amino acids that is 33.8% identical to the Yersinia enterocolitica O3 rfbH gene product, which is also required for O-antigen biosynthesis. Immunoblot analysis revealed that the sasA1 mutant, which was found to encode a nonsense codon in the beginning of rfbA, produced less O-antigen than sasA+ strains. These data indicate that the sasA locus is required for the biosynthesis of O-antigen and, when mutated, results in A-signal-independent expression of 4521.     

Inheritance of Strain Instability (Sectoring) in the Commercial Button Mushroom, Agaricus bisporus

The button mushroom, Agaricus bisporus, is a commercially important cultivated filamentous fungus. During the last decade, the button mushroom industry has depended mainly on two strains (or derivatives of these two strains). Using one of these highly successful strains (strain U1) we examined the phenomenon of strain instability, specifically, the production of irreversible sectors. Three “stromatal” and three “fluffy” sectors were compared with a healthy type U1 strain and with a wild-collected isolate. Compost colonization and fruit body morphology were examined. The main objective of this study, however, was to examine the meiotic stability of the sectored phenotype. Single basidiospores were isolated and subjected to a grain bioassay in which the ability to produce sectors was measured. Our results were as follows: (i) basidiospore cultures obtained from a wild-collected isolate showed no tendency to produce sectors; (ii) approximately 5% of the basidiospore cultures obtained from healthy type U1 strains produced irreversible sectors in the grain bioassay; (iii) the five primary sectors examined produced basidiospore cultures, half of which produced normal-looking growth in the grain bioassay and half of which produced some degree of sectoring; and (iv) the one sectored isolate that represented the F2 generation gave ratios similar to the 1:1 ratio observed for the F1 cultures.     

Multiple glucose 6-phosphate dehydrogenase-deficient variants correlate with malaria endemicity in the Vanuatu archipelago (southwestern Pacific).

In studying the relationship between genetic abnormalities of red blood cells and malaria endemicity in the Vanuatu archipelago in the southwestern Pacific, we have found that of 1,442 males tested, 98 (6.8%) were G6PD deficient. The prevalence of GdPD deficiency varied widely (0%-39%), both from one island to another and in different parts of the same island, and generally correlated positively with the degree of malaria transmission. The properties of G6PD from GdPD-deficient subjects were analyzed in a subset of 53 samples. In all cases the residual red-blood-cell activity was < 10%. There were three phenotypic patterns. PCR amplification and sequencing of the entire coding region of the G6PD gene showed that the first of these patterns corresponded to G6PD Union (nucleotide 1360C-->T; amino acid 454Arg-->Cys), previously encountered elsewhere. Analysis of samples exhibiting the second pattern revealed two new mutants: G6PD Vanua Lava (nucleotide 383T-->C; amino acid 128Leu-->Pro) and G6PD Namoru (nucleotide 208T-->C; amino acid 70Tyr-->His); in three samples, the underlying mutation has not yet been identified. Analysis of the sample exhibiting the third pattern revealed another new mutant: G6PD Naone (nucleotide 497G-->A; amino acid 166Arg-->His). Of the four mutations, G6PD Union and G6PD Vanua Lava have a polymorphic frequency in more than one island; and G6PD Vanua Lava has also been detected in a sample from Papua New Guinea. G6PD deficiency is of clinical importance in Vanuatu because it is a cause of neonatal jaundice and is responsible for numerous episodes of drug-induced acute hemolytic anemia.