Epichloë fungal endophyte interactions in perennial ryegrass (Lolium perenne L.) modified to accumulate foliar lipids for increased energy density

BACKGROUND

Commercial cultivars of perennial ryegrass infected with selected Epichloë fungal endophytes are highly desirable in certain pastures as the resulting mutualistic association has the capacity to confer agronomic benefits (such as invertebrate pest deterrence) largely due to fungal produced secondary metabolites (e.g., alkaloids). In this study, we investigated T2 segregating populations derived from two independent transformation events expressing diacylglycerol acyltransferase (DGAT) and cysteine oleosin (CO) genes designed to increase foliar lipid and biomass accumulation. These populations were either infected with Epichloë festucae var. lolii strain AR1 or Epichloë sp. LpTG-3 strain AR37 to examine relationships between the introduced trait and the endophytic association. Here we report on experiments designed to investigate if expression of the DGAT + CO trait in foliar tissues of perennial ryegrass could negatively impact the grass-endophyte association and vice versa. Both endophyte and plant characters were measured under controlled environment and field conditions.

RESULTS

Expected relative increases in total fatty acids of 17-58% accrued as a result of DGAT + CO expression with no significant difference between the endophyte-infected and non-infected progeny. Hyphal growth in association with DGAT + CO expression appeared normal when compared to control plants in a growth chamber. There was no significant difference in mycelial biomass for both strains AR1 and AR37, however, Epichloë-derived alkaloid concentrations were significantly lower on some occasions in the DGAT + CO plants compared to the corresponding null-segregant progenies, although these remained within the reported range for bioactivity.

CONCLUSIONS

These results suggest that the mutualistic association formed between perennial ryegrass and selected Epichloë strains does not influence expression of the host DGAT + CO technology, but that endophyte performance may be reduced under some circumstances. Further investigation will now be required to determine the preferred genetic backgrounds for introgression of the DGAT + CO trait in combination with selected endophyte strains, as grass host genetics is a major determinant to the success of the grass-endophyte association in this species.

Changes in Leaf-Level Nitrogen Partitioning and Mesophyll Conductance Deliver Increased Photosynthesis for Lolium perenne Leaves Engineered to Accumulate Lipid Carbon Sinks

Diacylglycerol acyl-transferase (DGAT) and cysteine oleosin (CO) expression confers a novel carbon sink (of encapsulated lipid droplets) in leaves of Lolium perenne and has been shown to increase photosynthesis and biomass. However, the physiological mechanism by which DGAT + CO increases photosynthesis remains unresolved. To evaluate the relationship between sink strength and photosynthesis, we examined fatty acids (FA), water-soluble carbohydrates (WSC), gas exchange parameters and leaf nitrogen for multiple DGAT + CO lines varying in transgene accumulation. To identify the physiological traits which deliver increased photosynthesis, we assessed two important determinants of photosynthetic efficiency, CO₂ conductance from atmosphere to chloroplast, and nitrogen partitioning between different photosynthetic and non-photosynthetic pools. We found that DGAT + CO accumulation increased FA at the expense of WSC in leaves of L. perenne and for those lines with a significant reduction in WSC, we also observed an increase in photosynthesis and photosynthetic nitrogen use efficiency. DGAT + CO L. perenne displayed no change in rubisco content or V_cmax but did exhibit a significant increase in specific leaf area (SLA), stomatal and mesophyll conductance, and leaf nitrogen allocated to photosynthetic electron transport. Collectively, we showed that increased carbon demand via DGAT+CO lipid sink accumulation can induce leaf-level changes in L. perenne which deliver increased rates of photosynthesis and growth. Carbon sinks engineered within photosynthetic cells provide a promising new strategy for increasing photosynthesis and crop productivity.

Negative pressure wound therapy, staged excision and definitive closure with split-thickness skin graft for axillary hidradenitis suppurativa: a retrospective study

OBJECTIVE

Bilateral axillary hidradenitis is a chronic, suppurative, and scarring disease that is most effectively treated by complete excision of all hair-bearing tissues. We assessed our staged procedure for excision and placement of a split-thickness skin graft for bilateral axillary hidradenitis in terms of costs, outcomes, and timing of excision.

METHOD

An IRB approved retrospective case analysis was performed on patients that underwent bilateral axillary hidradenitis skin excision with eventual placement of split-thickness skin grafting using the current LSUHSC/University Health hidradenitis surgical treatment protocol. Using ICD-9 codes (705.83) and CPT codes (11041, 11042, 11451, 11600, 11601, 11602, 11603, 11604) we reviewed cases performed at our institution from 1 January 2008 to 24 Febuary 2014 and we selected patients based on bilateral axillary involvement (alone) and >1 year history of active disease. Patients were excluded if resection of tissue encompassed regions outside of the immediately adjacent axillary.

RESULTS

A total of seven patients matching criteria for bilateral axillary hidradenitis were selected for analysis. Clinical course, cost and surgical techniques were assessed. Of the seven patients, six required admission throughout their treatment due to lack of funding making use of negative pressure wound therapy at home not possible. These patients stayed an average of 10 days with a mean hospital charge of $35,178 and a mean hospital provider charge of $10,019. No recurrence was demonstrated. All patients attained full range of motion, post grafting. No patient required a further operation due to graft failure.

CONCLUSION

Split-thickness skin grafting without use of bilayer dermal regenerative templates yielded definitive results with acceptable cosmesis and functionality, without the added cost of treatments such as a bilayer dermal regenerative template.

Knock-down of transcript abundance of a family of Kunitz proteinase inhibitor genes in white clover (Trifolium repens) reveals a redundancy and diversity of gene function

The transcriptional regulation of four phylogenetically distinct members of a family of Kunitz proteinase inhibitor (KPI) genes isolated from white clover (Trifolium repens; designated Tr-KPI1, Tr-KPI2, Tr-KPI4 and Tr-KPI5) has been investigated to determine their wider functional role. The four genes displayed differential transcription during seed germination, and in different tissues of the mature plant, and transcription was also ontogenetically regulated. Heterologous over-expression of Tr-KPI1, Tr-KPI2, Tr-KPI4 and Tr-KPI5 in Nicotiana tabacum retarded larval growth of the herbivore Spodoptera litura, and an increase in the transcription of the pathogenesis-related genes PR1 and PR4 was observed in the Tr-KPI1 and Tr-KPI4 over-expressing lines. RNA interference (RNAi) knock-down lines in white clover displayed significantly altered vegetative growth phenotypes with inhibition of shoot growth and a stimulation of root growth, while knock-down of Tr-KPI1, Tr-KPI2 and Tr-KPI5 transcript abundance also retarded larval growth of S. litura. Examination of these RNAi lines revealed constitutive stress-associated phenotypes as well as altered transcription of cellular signalling genes. These results reveal a functional redundancy across members of the KPI gene family. Further, the regulation of transcription of at least one member of the family, Tr-KPI2, may occupy a central role in the maintenance of a cellular homeostasis.

Genetic transformation of western clover (Trifolium occidentale D. E. Coombe.) as a model for functional genomics and transgene introgression in clonal pasture legume species

BACKGROUND

Western clover (Trifolium occidentale) is a perennial herb with characteristics compatible for its development as an attractive model species for genomics studies relating to the forage legume, white clover (Trifolium repens). Its characteristics such as a small diploid genome, self-fertility and ancestral contribution of one of the genomes of T. repens, facilitates its use as a model for genetic analysis of plants transformed with legume or novel genes.

RESULTS

In this study, a reproducible transformation protocol was established following screening of T. occidentale accessions originating from England, Ireland, France, Spain and Portugal. The protocol is based upon infection of cotyledonary explants dissected from mature seed with the Agrobacterium tumefaciens strain GV3101 carrying vectors which contain the bar selection marker gene. Transformation frequencies of up to 7.5% were achieved in 9 of the 17 accessions tested. Transformed plants were verified by PCR and expression of the gusA reporter gene, while integration of the T-DNA was confirmed by Southern blot hybridisation and segregation of progeny in the T1 generation.

CONCLUSIONS

Development of this protocol provides a valuable contribution toward establishing T. occidentale as a model species for white clover. This presents opportunities for further improvement in white clover through the application of biotechnology.

Mapping, complementation, and targets of the cysteine protease actinidin in kiwifruit

Cysteine proteases (CPs) accumulate to high concentration in many fruit, where they are believed to play a role in fungal and insect defense. The fruit of Actinidia species (kiwifruit) exhibit a range of CP activities (e.g. the Actinidia chinensis variety YellowA shows less than 2% of the activity of Actinidia deliciosa variety Hayward). A major quantitative trait locus for CP activity was mapped to linkage group 16 in a segregating population of A. chinensis. This quantitative trait locus colocated with the gene encoding actinidin, the major acidic CP in ripe Hayward fruit encoded by the ACT1A-1 allele. Sequence analysis indicated that the ACT1A locus in the segregating A. chinensis population contained one functional allele (A-2) and three nonfunctional alleles (a-3, a-4, and a-5) each containing a unique frameshift mutation. YellowA kiwifruit contained two further alleles: a-6, which was nonfunctional because of a large insertion, and a-7, which produced an inactive enzyme. Site-directed mutagenesis of the act1a-7 protein revealed a residue that restored CP activity. Expression of the functional ACT1A-1 cDNA in transgenic plants complemented the natural YellowA mutations and partially restored CP activity in fruit. Two consequences of the increase in CP activity were enhanced degradation of gelatin-based jellies in vitro and an increase in the processing of a class IV chitinase in planta. These results provide new insight into key residues required for CP activity and the in vivo protein targets of actinidin.

Diagnostic monitoring of a changing environment: an alternative UK perspective

Adaptive management of the marine environment requires an understanding of the complex interactions within it. Establishing levels of natural variability within and between marine ecosystems is a necessary prerequisite to this process and requires a monitoring programme which takes account of the issues of time, space and scale. In this paper, we argue that an ecosystem approach to managing the marine environment should take direct account of climate change indicators at a regional level if it is to cope with the unprecedented change expected as a result of human impacts on the earth climate system. We discuss the purpose of environmental monitoring and the importance of maintaining long-term time series. Recommendations are made on the use of these data in conjunction with modern extrapolation and integration tools (e.g. ecosystem models, remote sensing) to provide a diagnostic approach to the management of marine ecosystems, based on adaptive indicators and dynamic baselines.

Zinc is incorporated into cuticular "tools" after ecdysis: the time course of the zinc distribution in "tools" and whole bodies of an ant and a scorpion

An understanding of the developmental course of specialized accumulations in the cuticular "tools" of arthropods will give clues to the chemical form, function and biology of these accumulations as well as to their evolutionary history. Specimens from individuals representing a range of developmental stages were examined using MeV - Ion microscopy. We found that zinc, manganese, calcium and chlorine began to accumulate in the mandibular teeth of the ant Tapinoma sessile after pre-ecdysial tanning, and the zinc mostly after eclosion; peak measured zinc concentrations reached 16% of dry mass. Accumulations in the pedipalp teeth, tarsal claws, cheliceral teeth and sting (aculeus) of the scorpion Vaejovis spinigeris also began after pre-ecdysial tanning and more than 48 h after ecdysis of the second instars. Zinc may be deposited in the fully formed cuticle through a network of nanometer scale canals that we observed only in the metal bearing cuticle of both the ants and scorpions. In addition to the elemental analyses of cuticular "tools", quantitative distribution maps for whole ants were obtained. The zinc content of the mandibular teeth was a small fraction of, and independent of, the total body content of zinc. We did not find specialized storage sites that were depleted when zinc was incorporated into the mandibular teeth. The similarities in the time course of zinc, manganese and calcium deposition in the cuticular "tools" of the ant (a hexapod arthropod) and those of the scorpion (a chelicerate arthropod) contribute to the evidence suggesting that heavy metal-halogen fortification evolved before these groups diverged.

Polymerization of 2'-fluoro- and 2'-O-methyl-dNTPs by human DNA polymerase alpha, polymerase gamma, and primase

Studies were undertaken to assess the ability of human polymerase alpha (pol alpha) and polymerase gamma (pol gamma) to incorporate 2'-fluoro- and 2'-O-methyldeoxynucleotides into DNA. In vitro DNA synthesis systems were used to detect incorporation and determine K(m) and V(max) for 2'-FdATP, 2'-FdUTP, 2'-FdCTP, 2'-FdGTP, 2'-O-MedATP, 2'-O-MedCTP, 2'-O-MedGTP, 2'-O-MedUTP, dUTP, UTP, and FIAUTP, in addition to normal deoxynucleotides. Pol alpha incorporated all 2'-FdNTPs except 2'-FdATP, but not 2'-O-MedNTPs. Pol gamma incorporated all 2'-FdNTPs, but not 2'-O-MedNTPs. In general, 2'-fluorine substitution decreased V(max)/K(m) 2'-FdUTP. Because kinetics of insertion of pol alpha can be affected by the nature of the primer, we examined the ability of pol alpha to polymerize 2'-fluoro- and 2'-O-MedATP and dGTP when elongating a primer synthesized by DNA primase. Under these conditions, both 2'-FdATP and 2'-FdGTP were polymerized, but 2'-O-MedATP and 2'-O-MedGTP were not. Primase alone could not readily polymerize these analogs into RNA primers. Previous studies showed that 2'-deoxy-2'-fluorocytosine (2'-FdC) is incorporated by several non-human DNA polymerases. The current studies showed that human polymerases can polymerize numerous 2'-FdNTPs but cannot polymerize 2'-O-MedNTPs.

An evaluation of the toxicities of 2'-fluorouridine and 2'-fluorocytidine-HCl in F344 rats and woodchucks (Marmota monax)

The toxicities of 2'-fluorouridine (2'-FU) and 2'-fluorocytidine-HCl (2'-FC) were separately evaluated in 2 species, male Fischer 344 (F334) rats and woodchucks. Particular attention was focused on the ability of these nucleosides to induce toxicities similar to those induced by the antiviral drug fialuridine (FIAU). 2'-FU or 2'-FC was administered to F344 male rats by intravenous injection at doses of 5, 50, and 500 mg/kg/day for 90 consecutive days and to male and female woodchucks at doses of 0.75 and 7.5 mg/kg/day for 90 consecutive days. Clinical chemistry, hematology, and urinalysis (woodchuck only) profiles were assessed during and at the termination of the study. At necropsy, organs were weighed and tissues collected for routine histologic analysis. Cytochrome c oxidase activity, citrate synthase activity, and mitochondrial DNA content were measured, and micronucleus formation in the bone marrow (rats only) was evaluated. No adverse clinical effects were observed in either species. Rats treated with high doses of either 2'-FU or 2'-FC had body weights that were 90% of those of controls. 2'-FU and 2'-FC both induced a moderate decrease in the median lymphocyte count, and 2'-FC and 2'-FU induced a mild increase in mean corpuscular hemoglobin and mean corpuscular volume. Both compounds caused slight to moderate, reversible, histologic changes in the spleen and thymus. In the woodchuck, 2'-FC caused a slight increase in mean absolute lymphocytes, and 2'-FC and 2'-FU slightly increased hepatic periportal vacuolation and/or mononuclear cell infiltration. In summary, neither compound showed evidence of the toxicity induced by fialuridine in either species. Although compound effects were observed, none of these effects were considered to be adverse, and the no-observed adverse effect level was determined to be 500 mg/kg/day for both compounds in the male F344 rat and 7.5 mg/kg/day in the woodchuck.

Quantitative and qualitative differences in the metabolism of 14C-1,3-butadiene in rats and mice: relevance to cancer susceptibility

1,3-Butadiene (butadiene) is a potent carcinogen in mice, but not in rats. Metabolic studies may provide an explanation of these species differences and their relevance to humans. Male Sprague-Dawley rats and B6C3F1 mice were exposed for 6 h to 200 ppm [2,3-14C]-butadiene (specific radioactivity [sa] 20 mCi/mmol) in a Cannon nose-only system. Radioactivity in urine, feces, exhaled volatiles and 14C-CO2 were measured during and up to 42 h after exposure. The total uptake of butadiene by rats and mice under these experimental conditions was 0.19 and 0.38 mmol (equivalent to 3.8 and 7.5 mCi) per kg body weight, respectively. In the rat, 40% of the recovered radioactivity was exhaled as 14C-CO2, 70% of which was trapped during the 6-h exposure period. In contrast, only 6% was exhaled as 14C-CO2 by mice, 3% during the 6-h exposure and 97% in the 42 h following cessation of exposure. The formation of 14C-CO2 from [2,3-14C]-labeled butadiene indicated a ready biodegradability of butadiene. Radioactivity excreted in urine accounted for 42% of the recovered radioactivity from rats and 71% from mice. Small amounts of radioactivity were recovered in feces, exhaled volatiles and carcasses. Although there was a large measure of commonality, the exposure to butadiene also led to the formation of different metabolites in rats and mice. These metabolites were not found after administration of [4-14C]-1,2-epoxy-3-butene to animals by i.p. injection. The results show that the species differences in the metabolism of butadiene are not simply confined to the quantitative formation of epoxides, but also reflect a species-dependent selection of metabolic pathways. No metabolites other than those formed via an epoxide intermediate were identified in the urine of rats or mice after exposure to 14C-butadiene. These findings may have relevance for the prediction of butadiene toxicity and provide a basis for a revision of the existing physiologically based pharmacokinetic models.

Identification of novel metabolites of butadiene monoepoxide in rats and mice

Differences in the metabolism of 1,3-butadiene (Bd) in rats and mice may account for the observed species difference in carcinogenicity. Previous studies of the metabolic fate of Bd have identified epoxide formation as a key metabolic transformation which gives 1, 2-epoxy-3-butene (BMO), although some evidence of aldehyde metabolites is reported. In this study, male Sprague-Dawley rats and male B6C3F1 mice received single doses of [4-14C]BMO at 1, 5, 20, and 50 mg/kg of body weight (0.014, 0.071, 0.286, and 0.714 mmol/kg of body weight). Analysis of urinary metabolites indicated that both species preferentially metabolize BMO by direct reaction with GSH when given by ip administration. The excretion of (R)-2-(N-acetyl-L-cystein-S-yl)-1-hydroxybut-3-ene (IIa), 1-(N-acetyl-L-cystein-S-yl)-2-(S)-hydroxybut-3-ene (IIb), 1-(N-acetyl-L-cystein-S-yl)-2-(R)-hydroxybut-3-ene (IIc), and (S)-2-(N-acetyl-L-cystein-S-yl)-1-hydroxybut-3-ene (IId) accounted for 48-64% of urinary radioactivity in rats and 46-54% in mice. The metabolites originating from the R-stereoisomer of BMO (IIc and IId) predominated over those arising from the S-stereoisomer (IIa and IIb) in both species. IIc was formed preferentially in mice and IId in rats. The corresponding mercaptoacetic acids, S-(1-hydroxybut-3-en-2-yl)mercaptoacetic acid (IIf) and S-(2-hydroxybut-3-en-1-yl)mercaptoacetic acid (IIg), were identified only in mouse urine (ca. 20% of the recovered radioactivity). 4-(N-Acetyl-L-cystein-S-yl)-1,2-dihydroxybutane (Ia), a metabolite derived from hydrolysis of BMO, accounted for 10-17% of the radioactivity in rat and 6-10% in mouse urine. 4-(N-Acetyl-L-cystein-S-yl)-2-hydroxybutanoic acid (Ib), 3-(N-acetyl-L-cystein-S-yl)propan-1-ol (Ic), and 3-(N-acetyl-L-cystein-S-yl)propanoic acid (Id), also derived from the hydrolysis of BMO, were only present in the rat. Metabolites of 1,2,3,4-diepoxybutane (DEB) were not detected after administration of BMO in rat or mouse urine. This study showed both quantitative and qualitative differences in the metabolism of BMO with varying doses and between species. The data aid in the safety evaluation of Bd and contribute to the interpretation of mathematical models developed for quantitative risk assessment and extrapolation of animals to humans.

Association study of the 5' flanking regions of endothelial-nitric oxide synthase and endothelin-1 genes in familial primary open-angle glaucoma

1. Endothelium-derived substances are important regulators of the microcirculation. Endothelium-derived nitric oxide (NO), which is catalysed by nitric oxide synthase (NOS), is a potent modulator of vascular tone in the human ophthalmic artery, which is normally in a state of constant vasodilation due to the actions of NO. Endothelin-1 (ET-1) produces vasoconstriction of the anterior optic nerve vasculature and may be associated with glaucomatous optic neuropathy. The aetiology of primary open-angle glaucoma (POAG) remains largely unknown. Thus, alterations in the regulatory sequences of the genes coding for endothelium-derived NOS (eNOS) and ET-1 may have important effects in the development of POAG and were looked for in the present study. 2. In 56 patients with familial POAG and in 100 control subjects with no family history of hypertension or POAG, we examined the 5' flanking sequences of the eNOS and ET-1 genes, which contain many positive and negative regulatory regions affecting gene transcription, using polymerase chain reaction-based single strand conformation polymorphism analysis, to search for alterations. No variant in the promoter region of the ET-1 gene was observed in familial POAG or controls. Using three primer sets spanning 706 b.p. of the eNOS gene, we observed alterations in 11 of 56 (20%) familial POAG members and in seven of 100 (7%) controls. Sequence analysis demonstrated a C/T substitution at the 5' sequence position nucleotide (nt) -690 from the transcription start site, which lies between the cAMP regulatory element (nt -726 to -732) and an activator protein-1 binding domain (nt -655 to -661). 3. In summary, genotypic and allelic frequency analysis found no association between alterations in the promoter region of the ET-1 gene and familial POAG. A variant in the promoter region of the eNOS gene was seen in a significant percentage of familial POAG patients. Future expression studies will determine whether this polymorphism results in altered eNOS gene expression.

Public health approaches to community-based needs. Boston's infant mortality crisis as a case study

In light of a 10-year infant mortality crisis in Boston, a comprehensive public health approach was undertaken in which an extensive community-based needs assessment was used to develop a citywide maternal and child health improvement agenda. On the basis of the needs assessment, recommendations were made calling for community-based perinatal initiatives and midwifery services as critical elements in care for underserved communities and enhancement of perinatal services. A case description of one perinatal initiative illustrates the challenges of public health practice and describes a practice setting in which midwives provided leadership and guidance by using an interdisciplinary team approach in the implementation of a community empowerment project.

PCR-SSCP analysis of the glucocorticoid-responsive element of the atrial natriuretic peptide gene in familial primary open-angle glaucoma

1. Familial primary open-angle glaucoma (POAG) is a heterogeneous disease of unknown aetiology and the elucidation of the underlying genetic mechanisms contributing to phenotypic expression will be essential if earlier diagnosis of at-risk individuals and more specific medical treatment can be achieved. In a significant percentage of patients with POAG, intraocular pressure increases in response to topical ocular glucocorticoids. 2. Atrial natriuretic peptide (ANP) assists in the regulation of intraocular pressure levels and binding of the glucocorticoid receptor dimer to the glucocorticoid-responsive element in intron 2 of the ANP gene has been shown to increase ANP mRNA levels in vitro. We amplified and examined this sequence in the ANP gene by PCR-SSCP analysis in 100 patients with familial POAG and in 60 normal control subjects. No base alterations in the amplified product were found. 3. Thus, the present study found no evidence for an alteration in the sequence of the glucocorticoid-responsive element of the ANP gene that could alter ANP gene transcription in patients with familial POAG. The mechanism responsible for the increase in intraocular pressure levels in response to glucocorticoids is most likely independent of the glucocorticoid-responsive element in the ANP gene.

Insertion/deletion polymorphism of the angiotensin-converting enzyme gene and loss of the insertion allele in aldosterone-producing adenoma

The genetic mechanisms responsible for the formation of adrenocortical adenomas which autonomously produce aldosterone are largely unknown. The adrenal renin-angiotensin system has been implicated in the pathophysiology of these tumours. Angiotensin-converting enzyme (ACE) catalyses the generation of angiotensin II, and the insertion/deletion (I/D) polymorphism of the ACE gene regulates up to 50% of plasma and cellular ACE variability in humans. We therefore examined the genotypic and allelic frequency distributions of the ACE gene I/D polymorphism in 55 patients with aldosterone-producing adenoma, APA, (angiotensin-unresponsive APA n = 28, angiotensin-responsive APA n = 27), and 80 control subjects with no family history of hypertension. We also compared the ACE gene I/D polymorphism allelic pattern in matched tumour and peripheral blood DNA in the 55 patients with APA. The frequency of the D allele was 0.518 and 0.512 and the I allele was 0.482 and 0.488 in the APA and control subjects respectively. Genotypic and allelic frequency analysis found no significant differences between the groups. Examination of the matched tumour and peripheral blood DNA samples revealed the loss of the insertion allele in four of the 25 patients who were heterozygous for the ACE I/D genotype. The I/D polymorphism of the ACE gene does not appear to contribute to the biochemical and phenotypic characteristic of APA, however, the deletion of the insertion allele of the ACE gene I/D polymorphism in 16% of aldosterone-producing adenomas may represent the loss of a tumour suppressor gene/s or other genes on chromosome 17q which may contribute to tumorigenesis in APA.

Biological monitoring of butadiene exposure by measurement of haemoglobin adducts

The measurement of haemoglobin (Hb) adducts is an important tool for monitoring exposures to industrial chemicals such as ethylene, ethylene oxide and propylene oxide. The aim of the present study was to use this method to monitor occupational exposure to butadiene. The methodology was evaluated with Hb samples obtained by reacting butadiene monoepoxide (BMO), the primary reactive metabolite of 1,3-butadiene, with blood and by dosing BMO to rats and mice. The Hb adducts: N-(2-hydroxy-3-buten-1-yl)valine and N-(1-hydroxy-3-buten-2-yl)valine were determined as the pentaflurophenylthiohydantoin derivatives using the modified Edman degradation procedure and gas chromatography with negative ion chemical ionisation mass spectrometry. The adducts were quantified using d4-N-(2-hydroxyethyl)valine as an internal reference chemical. Relatively high background signals were observed which made accurate quantitation difficult. The lower limit of detection was estimated as 10-20 pmol/g globin. The experiments have demonstrated that appropriate reference samples are required for accurate quantitation and the method requires further refinement to improve the sensitivity of the analysis.

The atrial natriuretic peptide gene in patients with familial primary open-angle glaucoma

Family history is a major risk factor in the development of primary open-angle glaucoma. The atrial natriuretic peptide system has been implicated in the underlying pathophysiology of the disease. This study looked for any alterations in the ANP gene and 5' proximal promoter regions of the ANP gene, in 53 patients from familial primary open-angle glaucoma families. The ANP gene was amplified by a long-PCR technique from peripheral blood DNA. Gross insertions or deletions in the gene were sought and allelic frequencies at two restriction fragment length polymorphism (RFLP) sites within the gene (Sca I, Hpa II) were compared with allelic frequencies obtained from 60 normal controls with no known family history of glaucoma or ocular hypertension. PCR-based single strand conformation polymorphism analysis was then used to search for possible point mutations in the 5' proximal promoter region of the ANP gene, which is known to contain regulatory elements which modify gene transcription. No gross alterations in the ANP gene or differences in allelic frequencies at the RFLP sites within the gene were observed. PCR-SSCP analysis of the 5' proximal promoter region of the gene revealed mutations in 10 patients in the -595 to -384bp region (19% of patients). Mutations in the 5' proximal promoter region of the ANP gene may contribute to altered ANP transcription in at least a proportion of patients with familial glaucoma.

The effects of cross-link density and chemical exchange on magnetization transfer in polyacrylamide gels

The effects of polymer structure and water-macromolecule interactions on proton relaxation in an aqueous model polymer have been investigated using quantitative measurements of magnetization transfer. Polyacrylamide gels composed of 95% water, 5% comonomers acrylamide and N,N'-methylene-bis-acrylamide were studied. The structure and rigidity were varied by changing the cross-linking density of the polymer. The polymer showed a biphasic change in transverse relaxation with increasing cross-linking density which was accompanied by a sudden increase in magnetization transfer above 40% cross linking. This change may be attributed to the formation of rigid domains in the polymer which exhibit solid-like behavior with a short T2 (11 microseconds) and a Gaussian lineshape. Water-macromolecule interactions were controlled by varying the pH of the gel. At high pH (> 8), there was an increase in magnetization transfer and transverse relaxivity consistent with a chemical-exchange-mediated interaction between water protons and the polymer. By analyzing the system as two proton reservoirs coupled by magnetization exchange, the proton populations, intrinsic relaxation rates, and exchange rates were estimated, for different degrees of cross linking and pH. This model affords useful insights into the relevance of both supramolecular structure and chemical exchange on relaxation in tissues.

Long-PCR of the ANP gene and PCR-SSCP analysis of the proximal promoter region of the ANP gene in patients with aldosterone producing adenoma

Previous studies have shown a significant association between allelic frequencies at the ANP gene locus and aldosterone responsiveness to angiotensin in aldosterone-producing adenoma (APA). We searched for any gross insertions or deletions in the ANP gene in APA and any associations between allelic frequencies at the Hpa II and Sca I RFLP sites within the ANP gene and angiotensin-responsive and unresponsive APA and normal subjects. We also searched for possible point mutations in the promoter region of the ANP gene (-595 to transcription start site) in peripheral blood and tumor DNA from 59 patients with APA and in peripheral blood DNA from 39 normal subjects by polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) analysis. No large alterations in the ANP gene were observed, and no difference in allelic frequencies at the RFLP sites were seen between the two tumor subtypes, angiotensin-responsive and angiotensin-unresponsive APA, or between the APA group and normal subjects. SSCP analysis, however, did reveal mutations in the promoter region of the ANP gene (-375 to -595) in both peripheral blood and tumor DNA from 8 of 59 (14%) patients with APA, compared with only one of 39 normal controls (2.6%). This study suggests that alterations in the proximal promoter region of the ANP gene in APA may be important in the regulation of ANP transcription and may be involved in the underlying pathophysiology of aldosterone-producing adenoma in at least some patients.

The evaluation of methapyrilene for bacterial mutation with metabolic activation by Aroclor-induced, methapyrilene-induced and noninduced rat-liver S9

The antihistamine methapyrilene (MP) has been shown to be a potent hepatocarcinogen in rats. However, it has demonstrated little genotoxic activity in a wide variety of short-term tests. In this study, Fischer 344 rats were fed a carcinogenic dose of 0.1% methapyrilene in the diet for 10 weeks prior to sacrifice. S9 was prepared from the livers of the control, MP-treated and Aroclor-induced Fischer 344 rats. Each type of S9 was analyzed for mixed function oxidase activity, cytochrome P-450, and protein content. MP was then evaluated for mutagenicity in 6 strains of S. typhimurium (TA1535, TA1537, TA98, TA100, TA2638 and TA104) and one strain of E. coli (WP2uvrA-) using the standard plate-incorporation assay. MP was not mutagenic in any of the 7 bacterial strains when tested at concentrations < or = 10 mg/ml in the presence of each type of S9. However, in the absence of metabolic activation, an approximate 2-fold increase in revertants was noted with strain TA1535. The data from this study show that MP was not converted to a mutagenic metabolite by any of the three S9 types examined. However, the "weak" positive response with strain 1535 in the absence of metabolic activation indicates that further research is needed to elucidate the mechanism of action of this rat carcinogen.

The activity of the coat protein promoter of chloris striate mosaic virus is enhanced by its own and C1-C2 gene products

DNA fragments from the bidirectional promoter region of the geminivirus chloris striate mosaic virus (CSMV) were cloned into the pUC18-based vector, pG1 producing transcriptional fusions with the beta-glucuronidase (GUS) gene and nopaline synthase terminator sequence. The relative activity of each promoter construct was analyzed by a GUS expression assay of extracts from Zea mays (maize) Black Mexican Sweet protoplasts coelectroporated with the GUS reporter constructs and constructs in which individual CSMV open reading frames (ORFs) were placed under control of a cauliflower mosaic virus 35 S promoter. Weak promoter activity was observed for the promoter of the C1 and C2 ORFs (C1-C2 gene) and for the promoter of the V1 ORF. The activity of these promoters was unaffected by coelectroporation with the CSMV ORF constructs. Moderate activity was observed for the promoter of the V2 ORF (coat protein gene) which was enhanced by coelectroporation of the C1-C2 ORF construct. Sequences within the C1-C2 gene responsible for transactivation of the V2 ORF promoter were mapped close to the A site of a conserved NTP-binding sequence pattern within the C2 ORF. To a lesser extent activity for the promoter of the V2 ORF was enhanced by the V2 ORF construct providing evidence for positive autoregulation of the CSMV coat protein gene.

The nucleotide sequence of the infectious cloned DNA component of tobacco yellow dwarf virus reveals features of geminiviruses infecting monocotyledonous plants

An infectious clone of the Australian geminivirus tobacco yellow dwarf virus (TobYDV) was constructed from virus-specific double-stranded DNA isolated from infected tobacco and used to demonstrate a single-component genome. The nucleotide sequence of TobYDV DNA comprises 2580 nucleotides. TobYDV DNA has three coding regions, two in the virion sense and one in the complementary sense, homologous to those identified for other geminiviruses, particularly those infecting monocotyledonous (monocot) plants. The complementary sense coding region is comprised of two overlapping reading frames, with an intron of 86 nucleotides. Efficient splicing of the mRNA for this coding region was observed in the infected dicotyledonous (dicot) hosts bean and tobacco despite the intron having an A + U content (57%) more typical of geminiviruses of monocot plants. TobYDV encapsidates a small oligonucleotide able to prime synthesis of the complementary DNA strand in vitro. The TobYDV genome organization, low A + U intron, and encapsidated oligonucleotide primer resemble those of the monocot-infecting geminiviruses. These results strongly suggest that TobYDV is a monocot geminivirus which has become adapted to dicot hosts.

Synthesis and function of 8 alpha,25-dihydroxy-3-oxoneocholecalciferol in liver

25-Hydroxycholecalciferol (25-OHD3) is converted to 8 alpha,25-dihydroxy-3-oxoneocholecalciferol [8,25-(OH)2-3-oxoneo-D3] by liver microsomes, alveolar macrophages and myeloid leukemia cells. The characteristics of this reaction in liver microsomes have been determined. Omission of an NADPH-generating system or NADH resulted in a greater than 75% reduction in the production of 8,25-(OH)2-3-oxoneo-D3. In the absence of the cytosolic fraction, 25-OHD3 was converted to products that comigrated with 8,25-(OH)2-3-oxoneo-D3 on a silica column developed with hexane-isopropanol, thereby preventing quantitation. Production of 8,25-(OH)2-3-oxoneo-D3 was unaffected by EDTA and was stimulated by N,N'-diphenyl-p-phenylenediamine. Both progesterone and pregnenolone inhibited production of 8,25-(OH)2-3-oxoneo-D3; inhibition by progesterone was greater than that by pregnenolone. 8,25-(OH)2-3-Oxoneo-D3 did not bind the thymus receptor for 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] at concentrations 10-fold higher than that of 1,25-(OH)2D3. The lack of affinity of 8,25-(OH)2-3-oxoneo-D3 for the 1,25-(OH)2D3 receptor suggests that this metabolite is a degradative product of 25-OHD3, which might be produced when 25-OHD3 concentrations in the liver are excessive. Synthesis of this metabolite in the liver may be catalyzed by enzymes that also metabolize other steroids.

Metabolism in the rat of a model xenobiotic plant metabolite S-benzyl-N-malonyl-L-cysteine

1. The metabolism of a model xenobiotic plant metabolite S-benzyl-N-malonyl-L-cysteine (BMC) administered to rat at 10 mg/kg has been studied using a combination of radio-t.l.c. and h.p.l.c. 2. The major route of excretion for the administered 14C was via the urine (79% in 3 days). 3. The major metabolite was hippuric acid. The extent of biotransformation of BMC indicated the lability of the N-malonyl bond whose hydrolytic removal initiated a metabolic sequence which involved the action of C-S lyase to produce benzyl thiol. 4. A comparison of the findings from this study with those from experiments with N-acetyl-S-benzyl-L-cysteine and S-benzyl-L-cysteine is made to support the metabolic pathway proposed.

Identification of 8 alpha,25-dihydroxy-9,10-seco-4,6,10(19)-cholestatrien-3-one as a product of metabolism of 25-hydroxycholecalciferol by liver microsomes

The ability of liver microsomes, sites of synthesis of 25-hydroxycholecalciferol, to further metabolize 25-hydroxycholecalciferol has been assessed. When liver microsomes were incubated with 25-hydroxycholecalciferol in the presence of cytosol, a metabolite was isolated that comigrated with 8 alpha,25-dihydroxy-9,10-seco-4,6,10(19)-cholestatrien-3- one in three different chromatographic systems. The ultraviolet spectrum (220-350 nm) and mass spectrum of the purified metabolite were identical to that of synthetic 8 alpha,25-dihydroxy-9,10-seco-4,6,10(19)-cholestatrien-3-one. This study indicates that liver microsomes convert 25-hydroxycholecalciferol to 8 alpha,25-dihydroxy-9,10-seco-4,6,10(19)-cholestatrien-3-one. The significance of this metabolite, which has been shown previously by others to be produced by alveolar macrophages, has yet to be determined.

Cassava latent virus infections mediated by the Ti plasmid of Agrobacterium tumefaciens containing either monomeric or dimeric viral DNA

Plant infections with cassava latent virus (CLV) were mediated by the Ti plasmid of Agrobacterium tumefaciens containing either monomeric or dimeric copies of the virus genome. The CLV DNAs caused typical symptoms when they were inoculated in Agrobacterium strains C58, LBA4404 and a virE mutant A1026, but not other Agrobacterium strains with mutations in other vir loci or an E. coli polA strain. Virus-specific DNA forms characteristic of normal CLV infections were found after such infection. Characterization of progeny CLV DNA from selected plants identified several infectious mutants. These were found to be small insertions and/or deletions in the coat protein gene of DNA 1 and in the intergenic region of DNA 2.

Nucleotide sequence of the geminivirus chloris striate mosaic virus

The genome of chloris striate mosaic virus (CSMV) comprises a single circular DNA as determined by analyses on virion single-stranded (ss) DNA and virus-specific covalently closed circular (ccc) DNA isolated from infected plants. The nucleotide sequence of CSMV DNA was determined from cccDNA and the data were accommodated into one DNA circle of 2750 nucleotides. Comparison of the nucleotide sequence with those of maize streak virus (MSV), wheat dwarf virus (WDV), and digitaria streak virus (DSV) showed 49, 47, and 48% DNA homology, respectively. The sequence has four potential open reading frames for proteins of greater than 10,000 mol wt, two in the viral (+) sense and two in the complementary (-) sense. Three of these potential coding regions have homologous counterparts, by comparison of the amino acid sequences, among the open reading frames reported for MSV, WDV, and DSV. CSMV encapasidates primer molecules able to prime the synthesis in vitro of a complementary strand to virion DNA, initiating this reaction at one site on the genome. The CSMV primer comprising approximately 88 nucleotides was located within the smaller of two intergenic or noncoding regions.

Assessment of the genotoxic potential of unleaded gasoline and 2,2,4-trimethylpentane in human lymphoblasts in vitro

The potential of unleaded gasoline and 2,2,4-trimethylpentane to induce gene locus mutation and sister-chromatid exchange in human lymphoblasts in vitro was determined. Neither unleaded gasoline, at its maximum tolerated concentration in the medium, nor 2,2,4-trimethylpentane, at its limit of solubility, induced mutation at the thymidine kinase locus. Negative results were seen both in the presence and absence of a rat liver homogenate metabolizing system. Sister-chromatid exchange analyses of the cultures treated with unleaded gasoline and 2,2,4-trimethylpentane were also negative. Therefore the carcinogenicity and nephrotoxicity of unleaded gasoline and 2,2,4-trimethylpentane observed in vivo are not correlated with any marked genotoxicity in these in vitro tests.

Alpha-particle activity of apollo 11 samples

Nine polishled thin sectionis have been exposed to nulclear track plates, three have been counted by alplia-particle spectrometry, and one has been examined by electron mocroprobe. Interpretation of the results is in a preliminary stage. Alpha track distribiutioni in the autoradiograph of a breccia forms a network that appears related to the rims of accretionary lapilli comiiposinig the breccia. Thorium in a coarse-grained crystalline rock is concenitrated in micron-sized, zirconium-rich crystals. Alplia count rates agree with what would be predicted from previously reported thorium and uranium contents of the same rocks, suggesting secular equilibriunm for the thorium and uranium decay series.

Meteorite Fail at Pueblito de Allende, Chihuahua, Mexico: Preliminary Information

Specimens from the meteorite fall at 1:05 a. m., on 8 February 1969 at Pueblito de Allende, Chihuahua, Mexico, have been recovered. The meteorite is a chondrite (C3 and C4) with both opaque and microcrystalline matrices. Specimens were brought to a low background gamma counter less than 4 (1/2) days after the fall, and gamma rays from short-lived isotopes have been observed.

Lunar Receiving Laboratory

The Lunar Receiving Laboratory will be the permanent depository of a portion of the collection of lunar samples; it will safeguard the collection, providing continuing security and ensuring scientific integrity. In carrying out the time-dependent experiments and continuing functions of the laboratory, NASA will rely on visiting expert scientists supplementing a relatively small resident staff; outside scientists will be relied upon for most investigations and detailed analyses of samples. It is believed that the designed procedures and facilities provided will ensure the maximum scientific return from the Apollo Program in the way of information from lunar samples.