The use of cytogenetic tools for studies in the crop-to-wild gene transfer scenario

Interspecific hybridization in plants is an important evolutionary phenomenon involved in the dynamics of speciation that receives increasing interest in the context of possible gene escapes from transgenic crop varieties. Crops are able to cross-pollinate with a number of wild related species and exchange chromosome segments through homoeologous recombination. In this paper, we review a set of cytogenetic techniques that are appropriate to document the different steps required for the stable introgression of a chromosome segment from a donor species (i.e., the crop) into a recipient species (i.e., the wild). Several examples in hybrids and derivatives are given to illustrate how these approaches may be used to evaluate the potential for gene transfer between crops and wild relatives. Different techniques, from classical chromosome staining methods to recent developments in molecular cytogenetics, can be used to differentiate genomes and identify the chromosome regions eventually involved in genetic exchanges. Some clues are also given for the study of fertility restoration in the interspecific hybrid forms.

Grinding up wheat: a massive loss of nucleotide diversity since domestication

Several demographic and selective events occurred during the domestication of wheat from the allotetraploid wild emmer (Triticum turgidum ssp. dicoccoides). Cultivated wheat has since been affected by other historical events. We analyzed nucleotide diversity at 21 loci in a sample of 101 individuals representing 4 taxa corresponding to representative steps in the recent evolution of wheat (wild, domesticated, cultivated durum, and bread wheats) to unravel the evolutionary history of cultivated wheats and to quantify its impact on genetic diversity. Sequence relationships are consistent with a single domestication event and identify 2 genetically different groups of bread wheat. The wild group is not highly polymorphic, with only 212 polymorphic sites among the 21,720 bp sequenced, and, during domestication, diversity was further reduced in cultivated forms--by 69% in bread wheat and 84% in durum wheat--with considerable differences between loci, some retaining no polymorphism at all. Coalescent simulations were performed and compared with our data to estimate the intensity of the bottlenecks associated with domestication and subsequent selection. Based on our 21-locus analysis, the average intensity of domestication bottleneck was estimated at about 3--giving a population size for the domesticated form about one third that of wild dicoccoides. The most severe bottleneck, with an intensity of about 6, occurred in the evolution of durum wheat. We investigated whether some of the genes departed from the empirical distribution of most loci, suggesting that they might have been selected during domestication or breeding. We detected a departure from the null model of demographic bottleneck for the hypothetical gene HgA. However, the atypical pattern of polymorphism at this locus might reveal selection on the linked locus Gsp1A, which may affect grain softness--an important trait for end-use quality in wheat.

Preparation and ecotoxicity assessment of new biodegradable polyurethane foams

Flexible biodegradable polyurethane foams (BIO-PUR) were prepared by a one-shot process using commercially available coreactants and modified by substituting biodegradable additive based on the acetylated starch (AS), acetylcellulose (AC), 2-hydroxyethylcellulose (HEC) and carboxymethylcellulose sodium salt (CMC) for 5 or 10 wt% of commercial polyether polyol. The BIO-PUR foams were characterized by FTIR, TGA and polarization microscopy. Ecotoxicity of BIO-PUR foams freshwater extracts was evaluated using the alternative crustacean toxicity test Thamnotoxkit F. Values of toxicity were expressed as percentage mortality of the instars II-III larvae of freshwater fairy shrimps (Thamnocephalus platyurus) dependence on the effect criterion of the respective assay. The leaches of BIO-PUR foams modified with 5 or 10 wt% of HEC showed higher toxicity then other BIO-PUR foams, whereas leaches of BIO-PUR with 5wt% of AS and 10wt% of AC were even less toxic than REF. PUR foam.

Oral cleanliness of 12-13-year-old and 15-year-old school children of Sunsari District, Nepal

The aim of the study was to evaluate the oral cleanliness of school children in the District of Sunsari, Nepal. A multi-stage random sampling oral epidemiological survey was conducted in private and government, urban, rural town and rural village schools in 15 illakas of Sunsari District, Eastern Nepal. A total of 600, 12-13-year-old and 600 15-year-old school children were examined by trained examiners using the simplified oral hygiene index (OHI-S). The average age-group, debris and calculus index scores were combined to obtain the simplified oral hygiene index (OHI-S). The mean OHI-S scores were compared and evaluated using the parametric t-test for two independent samples. The mean OHI-S for urban 12-13-year-old school children was 0.98 compared to 1.34 for school children of rural towns and 1.44 for school children of rural villages and these differences in mean OHI-S were statistically significant (P < 0.005). In the 15-year-old age group, urban school children had a mean OHI-S score of 1.00 compared to 1.37 for rural towns and 1.43 for rural villages. The variance in the mean OHI-S scores were statistically significant (P < 0.005). The overall level of cleanliness in the school children surveyed was good. Children of urban schools had the lowest scores followed by school children from rural towns and then rural villages. When the mean OHI-S scores were compared with the DMFT scores, there was an inverse relationship between oral cleanliness and dental caries. Frequency of sugar consumption and the availability and affordability of fluoridated toothpaste may be important factors in the development of dental caries than oral cleanliness.

Dental caries and associated factors in 12-year-old schoolchildren in Thiruvananthapuram, Kerala, India

OBJECTIVES

The aims of the present study were to describe the dental health status of 12-year-old schoolchildren in Thiruvananthapuram, Kerala, India, and to identify sociodemographic factors, oral health behaviours, attitudes and knowledge related to dental caries experience.

METHODS

The study took the form of a cross-sectional survey of 838 children in upper primary schools. A two-stage cluster sampling technique was used. Dental caries was measured using World Health Organization criteria. Sociodemographic factors, oral health behaviours, attitudes and knowledge were assessed by a self-administered questionnaire.

RESULTS

The prevalence of dental caries in the permanent dentition was 27%. The mean number of decayed, missing and filled teeth was 0.5 (SD=0.9). The decayed component (D) constituted 91% of the total number of decayed, missing and filled teeth (DMFT). Multiple logistic regression analysis showed that children had a higher risk of having dental caries if they lived in urban area [OR=1.5, 95% confidence interval (CI)=1.1-2.1], had visited a dentist (OR=1.6, 95% CI=1.2-2.2), did not use a toothbrush (OR=1.9, 95% CI=1.2-2.9), consumed sweets (OR=1.4, 95% CI=1.0-1.9) or performed poorly in school (OR=1.7, 95% CI=1.0-2.3).

CONCLUSIONS

The prevalence of caries in this sample of 12-year-old schoolchildren was low compared to that in other developing countries. The present study indicated that urban living conditions were associated with more dental caries. Since urbanization is rapid in India, oral health promotion at the present time would be valuable to prevent increased caries prevalence.

Differential chromosome pairing affinities at meiosis in polyploid sugarcane revealed by molecular markers

Chromosome pairing at meiosis is an essential feature in cell biology, which determines trait inheritance and species evolution. Complex polyploids may display diverse pairing affinities and offer favorable situations for studying meiosis. The genus Saccharum encompasses diverse forms of polyploids with predominantly bivalent pairing. We have focused on a modern cultivar of sugarcane, R570, and taken advantage of a particular single copy probe (BNL 12.06) revealing 11 alleles by restriction fragment length polymorphism (RFLP). As for other cultivars, R570 is highly polyploid (2n=ca. 115) and indirectly derived from interspecific hybridization between Saccharum officinarum (2n=80, x=10) and S. spontaneum (2n=40-128, x=8). Here we determined the doses of the various BNL12.06 RFLP alleles among 282 progeny of R570 and estimated the mutual pairing frequencies among the corresponding homo- or homoeologous chromosomes using a maximum likelihood method. The result is an atypical picture, with pairing frequencies ranging from 0 to 40% and differential affinities leading to the identification of several chromosome subsets. This example illustrates the unsystematic meiotic behavior in a complex polyploid. It highlights a continuous range of pairing affinities between chromosomes and pinpoints a strong role of individual chromosome features, partly related to their ancestral origin, in the determination of these affinities.

The yeast phosphotyrosyl phosphatase activator protein, yPtpa1/Rrd1, interacts with Sit4 phosphatase to mediate resistance to 4-nitroquinoline-1-oxide and UVA

We previously reported the isolation of mutants hypersensitive to the genotoxic agent 4-nitroquinoline-1-oxide, a potent inducer of oxidative stress. One of the mutants was defective in a gene designated yPTPA1, encoding a protein related to the human phosphotyrosyl phosphatase activator hPTPA, which is believed to play a role in activating the serine/threonine phosphatase PP2A. Yeast yptpa1Delta mutants are also sensitive to the UVA component of sunlight known to produce reactive oxygen species, suggesting a role for yPtpa1 in oxidative stress response. We now report the characterization of another 4-nitroquinoline-1-oxide-sensitive mutant, EBY20. We show that this mutant is defective in the SIT4 gene encoding a catalytic subunit of the PP2A phosphatases and that sit4Delta mutants exhibit hypersensitivity to 4-nitroquinoline-1-oxide and UVA, but not to UVC at 254 nm. Like the yptpa1Delta mutants, sit4Delta mutants are also defective in the repair of 4-nitroquinoline-1-oxide-induced DNA lesions. Genetic analysis revealed that both yPtpa1 and Sit4 function in the same pathway to protect cells against the lethal effects of 4-nitroquinoline-1-oxide and UVA. Moreover, we demonstrate that yPtpa1-affinity columns specifically retain Sit4, confirming a previous report that these two proteins indeed belong to a complex. Cellular localization studies using GFP-tagged proteins reveals that yPtpa1 is localized to the cytoplasm and the nucleus, while the Sit4 protein shows an intense staining spot in the cytoplasm and diffused staining in this organelle. We suggest that the yPtpa1-Sit4 complex may participate in a novel mechanism that mediates repair of oxidative DNA damage caused by 4-nitroquinoline-1-oxide and UVA.

Dissecting cellulitis of the scalp with associated spondylarthropathy: case report and review

Arthritis is a well-recognized but uncommon accompaniment to several chronic cutaneous inflammatory conditions in which severe acne is one component. We report the case of a man with dissecting cellulitis of the scalp who developed severe peripheral and axial arthritis.

Yap1 overproduction restores arsenite resistance to the ABC transporter deficient mutant ycf1 by activating ACR3 expression

Ycf1 and Acr3 are transporters that have been previously shown to protect Saccharomyces cerevisiae cells from the toxic effects of arsenite. Ycf1 and Acr3 are positively regulated by distinct, but related bZIP transcriptional activators, Yap1 and Yap8, respectively. In this study, we show that overexpression of Yap1 complemented the arsenite hypersensitivity of the ycf1 null mutant, but only if the ACR3 gene is functional. We further show that the expression of either an ACR3-lacZ promoter fusion reporter or the endogenous ACR3 gene was stimulated by the overproduction of Yap1 upon exposure to arsenite. These data suggest that Yap1 confers arsenite resistance to the ycf1 null mutant by activating expression of the Yap8-dependent target gene, ACR3. Our data also show Yap8-dependent ACR3-lacZ expression was greatly stimulated by arsenite in a dose-dependent manner in the parental strain. However, overproduction of Yap1 in the parental strain severely limited dose-dependent activation of the reporter by arsenite. We conclude that Yap1 may compete with Yap8 for binding to the ACR3 promoter, but is unable to act as a potent activator.

MIF regulates innate immune responses through modulation of Toll-like receptor 4

Macrophages are pivotal effector cells of the innate immune system, which is vital for recognizing and eliminating invasive microbial pathogens. When microbial products bind to pathogen-recognition receptors, macrophages become activated and release a broad array of cytokines that orchestrate the host innate and adaptive immune responses. Initially identified as a T-cell cytokine, macrophage migration inhibitory factor (MIF) is also a macrophage cytokine and an important mediator of inflammation and sepsis. Here we report that MIF is an essential regulator of macrophage responses to endotoxin (lipopolysaccharide) and Gram-negative bacteria. Compared with wild-type cells, MIF-deficient macrophages are hyporesponsive to lipopolysaccharide and Gram-negative bacteria, as shown by a profound reduction in the activity of NF-kappaB and the production of tumour-necrosis factor-alpha. This reduction is due to a downregulation of Toll-like receptor 4 (TLR4), the signal-transducing molecule of the lipopolysaccharide receptor complex, and is associated with decreased activity of transcription factor PU.1, which is required for optimal expression of the Tlr4 gene in myeloid cells. These findings identify an important role for MIF in innate immunity and provide a molecular basis for the resistance of MIF-deficient mice to endotoxic shock.

Interaction of flunarizine with sodium valproate or ethosuximide in gamahydroxybutyrate induced absence seizures in rats

Sodium valproate(VPA), ethosuximide(ESM), 200 mg/kg ip and flunarizine (FLU) 5 or 10 mg/kg ip were first administered independently to rats in order to study their effects on behavioural and EEG aspects of spike and wave discharges (SWDs) induced by y- hydroxybutyrate (GHB,100 mg/kg ip). GHB treated rats show behavioural changes and concomitant repetitive EEG episodes of 7 to 9 Hz SWDs, mimicking human absence seizures (AS), and can be used as a pharmacological model. The number and duration of SWDs were calculated for 1 hr from the EEG and were parameters for drug evaluation. VPA and ESM at 200 mg/kg, significantly reduced SWD number and duration/hr, while FLU showed significant reduction only at 10 but not at 5 mg/kg. Combination of FLU, 10 mg/kg with either VPA or ESM showed significant reduction of SWD number and duration, suggesting an additive effect of the anti-absence agents with the calcium channel blocker, FLU, on experimental absence seizures in rats.

Detection of West Nile virus in mosquitoes by RT-PCR

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay employing <<TaqMan>> detection technology was developed to identify West Nile virus in experimentally infected mosquitoes. The specificity of the assay was evaluated with the following viruses: eastern equine encephalitis, Ilheus, West Nile and yellow fever viruses. The limits of detection were determined using West Nile viral RNA extracted from serial dilutions of virus culture in infected mosquitoes. Limit of detection was 5 PFU from extracted mosquitoes. We were able to detect the presence of one infected mosquito in a pool of 50 repeatedly. When the RT-PCR was used with coded samples of intrathoracically-infected and uninfected mosquitoes, the assay detected the virus in all infected mosquitoes. Analytic sensitivity and specificity were 100%. This assay offers an efficient and rapid method of identifying West Nile virus in infected mosquitoes or cell culture.

Azithromycin versus ceftriaxone for the treatment of uncomplicated typhoid fever in children

A total of 108 children aged 4-17 years were randomized to receive 7 days of azithromycin (10 mg/kg/day; maximum, 500 mg/day) or ceftriaxone (75 mg/kg/day; maximum, 2.5 g/day), to assess the efficacy of the agents for the treatment of uncomplicated typhoid fever. Salmonella typhi was isolated from the initial cultures of blood samples from 64 patients. A total of 31 (91%) of the 34 patients treated with azithromycin and 29 (97%) of the 30 patients treated with ceftriaxone were cured (P>.05). All 64 isolates were susceptible to azithromycin and ceftriaxone. Of the patients treated with ceftriaxone, 4 subsequently had relapse of their infection. No serious side effects occurred in any study subject. Oral azithromycin administered once daily appears to be effective for the treatment of uncomplicated typhoid fever in children. If these results are confirmed, the agent could be a convenient alternative for the treatment of typhoid fever, especially in individuals in developing countries where medical resources are scarce.

Preparation of a pure autologous biodegradable fibrin matrix for tissue engineering

Parallel to the growing role of tissue engineering, the need for cell embedding materials, which allow cells to stabilise in a three-dimensional distribution, has increased. Although several substances have been tested, fibrin is thus far the only one that permits the clinical application of cultured tissue. To date, autologous fibrinogen has usually been polymerised with bovine thrombin, which can cause severe immunological side effects. The objective of this study was to explore the practicability of obtaining autologous thrombin from a single patient in an adequate concentration and amount. Fibrinogen was cryoprecipitated from 200 ml of freshly-frozen plasma. Thrombin was isolated from the supernatant through ion-exchange chromatography. The thrombin was first bound to Sephadex A-50 and then eluated using 2 ml of a salt buffer (2.0 M NaCl in 0.015 M trisodiumcitrate, pH 7.0). The activity of the thrombin (51 NIH x ml(-1) to 414 NIH x ml(-1) reached levels comparable to those in commercially available fibrin glues (4-500 NIH x ml(-1)). The study has shown that it is possible to obtain a sufficient amount of autologous thrombin from a single donor to create a fibrin matrix of high efficiency without the risk of immunological and infectious side effects.

Expression and coreceptor function of APJ for primate immunodeficiency viruses

APJ is a seven transmembrane domain G-protein-coupled receptor that functions as a coreceptor for some primate immunodeficiency virus strains. The in vivo significance of APJ coreceptor function remains to be elucidated, however, due to the lack of an antibody that can be used to assess APJ expression, and because of the absence of an antibody or ligand that can block APJ coreceptor activity. Therefore, we produced a specific monoclonal antibody (MAb 856) to APJ and found that it detected this receptor in FACS, immunofluorescence, and immunohistochemistry studies. MAb 856 also recognized APJ by Western blot, enabling us to determine that APJ is N-glycosylated. Using this antibody, we correlated APJ expression with coreceptor activity and found that APJ had coreceptor function even at low levels of expression. However, we found that APJ could not be detected by FACS analysis on cell lines commonly used to propagate primate lentiviruses, nor was it expressed on human PBMC cultured under a variety of conditions. We also found that some viral envelope proteins could mediate fusion with APJ-positive, CD4-negative cells, provided that CD4 was added in trans. These findings indicate that in some situations APJ use could render primary cell types susceptible to virus infection, although we have not found any evidence that this occurs. Finally, the peptide ligand for APJ, apelin-13, efficiently blocked APJ coreceptor activity.

Comparative profiles of sodium valproate and ethosuximide on electro-behavioural correlates in gamma-hydroxybutyrate and pentylenetetrazol induced absence seizures in rats

Sodium valproate (VPA) and ethosuximide (ESM) were compared on behavioural and EEG changes in gamma-hydroxybutyrate (GHB) and pentylenetetrazole (PTZ) rat models of Absence Seizures (AS). Both GHB, 100 mg/kg i.p. and PTZ, 20 mg/kg i.p., produced repetitive episodes of staring and immobility with concomitant 6 to 9 Hz spike and wave discharges (SWDs) in the EEG. The parameters used for drug evaluation were the number and duration of SWDs/hour. Though the number of SWDs/hour produced by GHB and PTZ were not significantly different, the duration of SWDs was significantly longer in GHB treated rats (P < 0.001) VPA and ESM, at 200 mg/kg i.p., reduced SWD number and duration in GHB pretreated rats, whereas ESM, 50 mg/kg i.p., was four times more effective than VPA, 200 mg/kg i.p., in the PTZ model. Phenytoin (PHY) 20 and Carbamazepine (CBZ) 10 mg/kg i.p., worsened AS, a feature which has also been reported clinically. Both rat models of experimental AS can be used to defect potential anti-absence activity in new chemical entities.

Microbial quality of water in rural communities of Trinidad

A cross-sectional study was conducted in four rural communities of northeastern Trinidad to determine the microbial quality of water supply to households and that quality's relationship to source and storage device. Of the 167 household water samples tested, total coliforms were detected in 132 of the samples (79.0%), fecal coliforms in 102 (61.1%), and E. coli in 111 (66.5%). There were significant differences among the towns in the proportion of the samples contaminated with coliforms (P < 0.001) and E. coli (P < 0.001). Of 253 strains of E. coli studied, 4 (1.6%) were mucoid, 9 (3.6%) were hemolytic, and 37 (14.6%) were nonsorbitol fermenters. Of 69 isolates of E. coli tested, 10 (14.5%) were verocytotoxigenic. Twenty-eight (14.0%) of 200 E. coli isolates tested belonged to enteropathogenic serogroups. Standpipe, the most common water source, was utilized by 57 (34.1%) of the 167 households. Treated water (pipeborne in homes, standpipes, or truckborne) was supplied to 119 households (71.3%), while 48 households (28.7%) used water from untreated sources (rain, river/stream, or well) as their primary water supply. The type of household storage device was associated with coliform contamination. Water stored in drums, barrels, or buckets was more likely to harbor fecal coliforms (74.2% of samples) than was water stored in tanks (53.3% of samples), even after controlling for water source (P = 0.04). Compared with water from other sources, water piped into homes was significantly less likely to be contaminated with total coliforms (56.9% versus 88.8%, P < 0.001) and fecal coliforms (41.2% versus 69.8%, P < 0.01), even when the type of storage device was taken into account. However, fecal contamination was not associated with whether the water came from a treated or untreated source. We concluded that the drinking water in rural communities in Trinidad was grossly unfit for human consumption, due both to contamination of various water sources and during household water storage.

Randomized, placebo-controlled, crossover trial of low-dose oral methotrexate in children with extended oligoarticular or systemic arthritis

OBJECTIVE

Juvenile idiopathic arthritis (JIA) can persist through adolescence and adulthood, resulting in significant disability. The use of low-dose oral methotrexate (MTX) for persistent polyarthritis has been shown to be effective by the USA/USSR collaborative study group. However, 2 of the most disabling subgroups of JIA, systemic and extended oligoarthritis, were underrepresented in that study. The present study was therefore conducted to investigate the efficacy of MTX in these 2 subgroups.

METHODS

Patients under the age of 16 years who fulfilled the International League of Associations for Rheumatology criteria for systemic or extended oligoarticular arthritis were eligible for this multicenter, double-blind, placebo-controlled crossover trial. Forty-five patients with systemic and 43 with extended oligoarticular arthritis were enrolled. The dosage of MTX or placebo was 15 mg/m2, which could be increased to 20 mg/m2 after 2 months. Core outcome variables were considered as primary measures, giving a final score of "improved" or "not improved." Secondary measures included scores of systemic features and biochemical laboratory measures. Assessment of function was not included since there were no validated functional measures at the start of this trial in 1991.

RESULTS

In the extended oligoarticular arthritis group, MTX treatment produced significant improvement in 3 of 5 core variables (erythrocyte sedimentation rate, physician's global assessment of disease activity, and parent's global assessment of disease activity). By the primary improvement criteria, there was significant overall improvement during MTX treatment. In the systemic arthritis group, only 2 of 5 core variables were significantly improved (physician's and parent's global assessment of disease activity). Systemic features were not part of the core variables, but the systemic feature score was not significantly different between MTX and placebo treatment. There was no significant overall improvement in this group during MTX treatment. However, no significant interaction between disease subgroup and treatment effect was demonstrated. When the data from both disease subgroups were combined, there was significant clinical improvement during MTX treatment (P = 0.006).

CONCLUSION

MTX 15-20 mg/m2 given orally once a week was found to be an effective treatment for both extended oligoarticular and systemic JIA in this shortterm trial. Long-term efficacy needs to be addressed in future studies.

[Phenotypic convergence among pentacrines Endoxocrinus and Diplocrinus related to environmental constraints]

Morphological converging and diverging trends are demonstrated using detailed biometric analyses of the skeleton in pentacrinid populations of the Diplocrininae subfamily living in tropical western Atlantic and in the Pacific Ocean. According to environmental data obtained by in situ submersible observations, water flow characteristics (laminar or with eddies) appear to be the main factor controlling phenotypes through ontogeny. Evidence of convergence between different taxa may be explained by ecological niches with eddies.