Cleavage of DNA without loss of genetic information by incorporation of a disaccharide nucleoside

A ribose residue inserted between the 3′-OH of one nucleotide and the 5′-phosphate group of the next nucleotide, functions as a site-specific cleavage site within DNA. This extra ribose does not interrupt helix formation and it protects duplex DNA against cleavage by restriction enzymes. Cleavage can be obtained with periodate and all ribose fragments can be removed with sodium hydroxide. As a result of this, an intact natural oligodeoxynucleotide is obtained after ligation reaction, which means that site-specific cleavage and recovering of intact DNA occurs without loss of genetic information.     

Barriers to uptake of services for coronary heart disease: qualitative study

ObjectivesTo identify factors within the South Yorkshire coalfields that influence use of health services by people with angina.DesignQualitative study using semistructured individual and group interviews.SettingGeneral practice and community settings in Barnsley and Rotherham health authorities.Participants14 patients with stable angina and nine primary care staff had individual interviews plus five community groups and one group of general practitioners.ResultsA complex web of factors was identified that prevented, delayed, or facilitated referral to secondary care. Delay, denial, and self management by patients meant that the full extent of symptoms often remained hidden from general practitioners, resulting in a delayed or missed referral. Barriers identified fell into six categories: structural, personal, social and cultural, past experience and expectations, diagnostic confusion, and knowledge and awareness.ConclusionsMany of the factors influencing referral operate before general practitioners become involved. Community development could be one way of tackling inequalities and promoting sustainable change. Structural changes are needed to improve access and increase the acceptability of general practice services. Primary care staff should be educated to detect underreporting of symptoms and promote appropriate referral.

What is already known on this topic

An inverse correlation has been shown between deprivation and cardiac revascularisationFear of hospitals, denial of ill health, and low expectations may prevent people with angina accessing health services

What this study adds

Fear, denial, and low expectations were important barriers to accessing health services, reinforcing earlier findingsOther factors may be specific to the study population—for example, coping, independence, and attributing symptoms to industrially related lung diseaseMany of the barriers operate before general practitioners are involved, making it difficult to identify solutions     

Differing effects of endocrine-disrupting chemicals on basal and FSH-stimulated progesterone production in rat granulosa-luteal cells

Previous studies have shown that the phytoestrogen, genistein, inhibits basal and forskolin-stimulated progesterone synthesis in rat granulosa-luteal cells. Genistein, however, not only binds and activates the estrogen receptor (ER), but is also a potent inhibitor of tyrosine kinase. In these studies we have compared the effects of estradiol, two other phytoestrogens, apigenin and coumarin, the pesticide, [2-(chlorphenyl)-2-(4-chlorphenyl)-1,1,1-trichlorethan] (2,4'DDT), and the industrial chemical, 4-octyl-phenol, on basal and follicle stimulating hormone (FSH)-stimulated progesterone production in the same experimental system. Only a supraphysiological dose of estradiol (10(-5) M) significantly inhibited basal and forskolin-stimulated progesterone production in granulosa-luteal cells, but had no effect on FSH-stimulated production. In contrast, apigenin, DDT, and octyl-phenol stimulated basal progesterone production at doses around 10(-8) to 10(-7) M, but this effect was reversed at higher doses. Coumarin was without effect. Like basal production, the two phytoestrogens had opposing effects on FSH-stimulated progesterone production. Genistein at 10(-5) M was inhibitory, while apigenin significantly potentiated the response at 19(-7) M. In contrast, DDT had no effect on the FSH-induced response, though 10(-7) M octyl-phenol nearly doubled the response. While all these chemicals are known to interact with the estrogen receptor to a greater or lesser extent, these studies suggest that like genistein, these different endocrine-disrupting chemicals may have other actions apart from those on the estrogen receptor.     

Enhanced selection for MHC diversity in social tuco-tucos

To explore the effects of behavior and demography on balancing selection at major histocompatibility complex (MHC) loci, we examined allelic diversity at exon 2 of the MHC class II DQbeta locus in a social and a solitary species of tuco-tuco (Rodentia: Ctenomyidae: Ctenomys), both of which occur in the same valley in southwestern Argentina. By comparing patterns of diversity at this MHC gene to the diversity evident at fifteen microsatellite loci, we demonstrate that balancing selection at the DQbeta locus is enhanced in the social species compared to its solitary congener. These findings have intriguing implications for the role of behavioral and demographic parameters in maintaining diversity at MHC loci.     

Comparative activity of baculoviruses against the codling moth Cydia pomonella and three other tortricid pests of tree fruit

The granulovirus of Cydia pomonella (L.) (CpGV) offers potential for selective control of codling moth. Two major limitations of CpGV are its narrow host range and lack of persistence in the orchard agroecosystem. The nucleopolyhedroviruses of the alfalfa looper Autographa californica (Speyer) (AcMNPV) and those of the celery looper Anagrapha falcifera (Kirby) (AfMNPV) have broad host ranges. Comparative assays of CpGV, AcMNPV, and AfMNPV against codling moth neonate larvae revealed a 54-93-fold greater susceptibility of codling moth to the granulovirus than to the two nucleopolyhedroviruses based on the LC(50) values for each virus. The LC(50)s for CpGV, AfMNPV, and AcMNPV were 32.7 capsules/mm(2), 1.77 x 10(3) occlusion bodies (OBs)/mm(2), and 3.05 x 10(3)OBs/mm(2), respectively. The LT(50) determined for AfMNPV using an approximate LC(95) of the virus against neonate larvae was 3.6 days. Histological examination of tissues in moribund codling moth larvae that had been treated with AfMNPV revealed the presence of nonoccluded and unenveloped virus rods in midgut tissue. Neither OBs nor signs of infection were detected in other tissues. The activity of AfMNPV was also evaluated in three other tortricid apple pests (obliquebanded leafroller, Choristoneura rosaceana (Harris); Pandemis leafroller, Pandemis pyrusana Kearfott; and the oriental fruit moth, Grapholitha molesta (Busck)). Codling and Oriental fruit moths were significantly more susceptible to AfMNPV than were the two leafroller species.     

Functional analysis by site-directed mutagenesis of the NAD(+)-reducing hydrogenase from Ralstonia eutropha

The tetrameric cytoplasmic [NiFe] hydrogenase (SH) of Ralstonia eutropha couples the oxidation of hydrogen to the reduction of NAD(+) under aerobic conditions. In the catalytic subunit HoxH, all six conserved motifs surrounding the [NiFe] site are present. Five of these motifs were altered by site-directed mutagenesis in order to dissect the molecular mechanism of hydrogen activation. Based on phenotypic characterizations, 27 mutants were grouped into four different classes. Mutants of the major class, class I, failed to grow on hydrogen and were devoid of H(2)-oxidizing activity. In one of these isolates (HoxH I64A), H(2) binding was impaired. Class II mutants revealed a high D(2)/H(+) exchange rate relative to a low H(2)-oxidizing activity. A representative (HoxH H16L) displayed D(2)/H(+) exchange but had lost electron acceptor-reducing activity. Both activities were equally affected in class III mutants. Mutants forming class IV showed a particularly interesting phenotype. They displayed O(2)-sensitive growth on hydrogen due to an O(2)-sensitive SH protein.     

Enrichment of a microbial culture capable of degrading endosulphate, the toxic metabolite of endosulfan

AIMS: The aim of this study was to isolate a source of enzymes capable of degrading endosulphate (endosulfan sulphate), the toxic metabolite of the pesticide endosulfan. METHODS AND RESULTS: A microbial broth culture capable of degrading endosulphate was enriched from endosulfan-contaminated soil by providing the metabolite as the sole source of sulphur in broth culture. No microbial growth was observed in the absence of endosulphate. In the presence of endosulphate, growth of the culture occurred with the concomitant formation of three chlorine-containing compounds. Thin layer chromatography and gas chromatography--mass spectral analysis identified these metabolites as endosulfan monoaldehyde, 1,2,3,4,7,7-hexachloro-5,6-bis(methylene)bicyclo[2.2.1]-2-heptene and 1,2,3,4,7,7-hexachloro-5-hydroxymethylene-6-methylenebicyclo[2.2.1]-2-heptene. The second and third compounds have not been reported in previous metabolic studies. The enriched culture was also able to utilize alpha- and beta-endosulfan as sulphur sources, each producing the hydrolysis product endosulfan monoaldehyde as the sole chlorine-containing metabolite. Alpha-endosulfan was more readily hydrolysed than the beta-isomer. CONCLUSIONS: This study isolated a mixed microbial culture capable of degrading endosulphate. The products of degradation were characterized as novel endosulfan metabolites. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes the isolation of a mixed microbial culture that is potentially a valuable source of hydrolysing enzymes for use in enzymatic bioremediation, particularly of endosulphate and alpha-endosulfan residues.     

KGF pretreatment decreases B7 and granzyme B expression and hastens repair in lungs of mice after allogeneic BMT

We investigated keratinocyte growth factor (KGF) as a pretreatment therapy for idiopathic pneumonia syndrome (IPS) generated as a result of lung damage and allogeneic T cell-dependent inflammatory events occurring in the early peri-bone marrow (BM) transplant (BMT) period. B10.BR (H2(k)) recipient mice were transplanted with C57BL/6 (H2(b)) BM with spleen cells after lethal irradiation with and without cyclophosphamide conditioning with and without subcutaneous KGF pretreatment. KGF-pretreated mice had fewer injured alveolar type II (ATII) cells at the time of BMT and exhibited ATII cell hyperplasia at day 3 post-BMT. The composition of infiltrating cells on day 7 post-BMT was not altered by KGF pretreatment, but the frequencies of cells expressing the T-cell costimulatory molecules B7.1 and B7.2 and mRNA for the cytolysin granzyme B (usually increased in IPS) were decreased by KGF. Sera from KGF-treated mice had increases in the Th2 cytokines interleukin (IL)-4, IL-6, and IL-13 4 days after cessation of KGF administration (i.e., at the time of BMT). These data suggest that KGF hinders IPS by two modes: 1) stimulation of alveolar epithelialization and 2) attenuation of immune-mediated injury as a consequence of failure to upregulate cytolytic molecules and B7 ligand expression and the induction of anti-inflammatory Th2 cytokines in situ.     

Variation in the Bemisia tabaci s. l. species complex (Hemiptera: Aleyrodidae) and its natural enemies leading to successful biological control of Bemisia biotype B in the USA

Parasitoids of the Bemisia tabaci (Gennadius) species complex collected in Spain and Thailand were evaluated as biological control agents of B. tabaci biotype B in cole crops in Texas, USA. Parasitoids were identified by morphological and RAPD-PCR analyses. The most abundant parasitoid from Spain was Eretmocerus mundus Mercet with apparent field parasitism of 39-44%. In Thailand, Encarsia formosa Gahan, E. transvena Timberlake, E. adrianae Lopez-Avila, Eretmocerus sp. 1 and sp. 2 emerged, with apparent field parasitism of 1-65%. Identification and molecular classification of B. tabaci associated with parasitoid collections and in the release site in Texas were accomplished using morphological traits and nucleotide sequence comparison of the mitochondrial cytochrome oxidase I gene (COI) (700-720 bp). Collections of B. tabaci from Thailand grouped separately from B types from Arizona and Florida and the target B type from Texas, USA, a cluster from India, and other New World B. tabaci. The Spanish B. tabaci host of E. mundus which was laboratory and field-tested to achieve biological control of the B type was most closely related to non-B type B. tabaci populations from Spain and Sudan, the latter which formed a second group within the larger clade that also contained the B type cluster. Laboratory tests indicated that E. mundus from Spain parasitized more B. tabaci type B than did Eretmocerus spp. native to Texas and other exotic parasitoids evaluated. Eretmocerus mundus from Spain also successfully parasitized B. tabaci type B when field-released in a 0.94 million ha test area in Texas, and has significantly enhanced control of B. tabaci type B in California, USA. In contrast, parasitoids from Thailand failed to establish in the field in Texas, collectively suggesting a positive correlation between the centres of diversity of compatible parasitoid-host complexes.