Sequence and diversity of MHC <Emphasis Type="Italic">DQA</Emphasis> and<Emphasis Type="Italic"> DQB</Emphasis> genes of the owl monkey<Emphasis Type="Italic"> Aotus nancymaae</Emphasis>

The New World primate Aotus nancymaae has been recommended by the World Health Organization (WHO) as a model for evaluation of malaria vaccine candidates, given its susceptibility to experimental infection with the human malaria parasites Plasmodium falciparum and Plasmodium vivax. We present here the nucleotide sequences of the complete cDNA of MHC-DQA1 and of the polymorphic exon 2 segments of MHC-DQB1/DQB2. In a group of three nonrelated animals captured in the wild, five alleles of MHC-DQA1 could be identified. They all belong to one lineage, namely Aona-DQA1*27. This lineage has not been described in any other New World monkey species studied. In a group of 19 unrelated animals, 14 Aona-DQB1 alleles could be identified which are grouped into the two lineages Aona-DQB1*22 and Aona-DQB1*23. These lineages have been described previously in the common marmoset and cotton-top tamarin. In addition, two Aona-DQB2 sequences could be identified which are highly similar to HLA-DQB2 sequences. Essential amino acid residues contributing to MHC DQ peptide binding pockets number 1 and 4 are conserved or semi-conserved between HLA-DQ and Aona-DQ molecules, indicating a capacity to bind similar peptide repertoires. These results fully support the use of Aotus monkeys as an animal model for evaluation of future subunit vaccine candidates.     

Sequence and diversity of DRB genes of Aotus nancymaae, a primate model for human malaria parasites

 The New World primate Aotus nancymaae is susceptible to infection with the human malaria parasite Plasmodium falciparum and Plasmodium vivax and has therefore been recommended by the World Health Organization as a model for evaluation of malaria vaccine candidates. We present here a first step in the molecular characterization of the major histocompatibility complex (MHC) class II DRB genes of Aotus nancymaae (owl monkey or night monkey) by nucleotide sequence analysis of the polymorphic exon 2 segments. In a group of 15 nonrelated animals captivated in the wild, 34 MHC DRB alleles could be identified. Six allelic lineages were detected, two of them having human counterparts, while two other lineages have not been described in any other New World monkey species studied. As in the common marmoset, the diversity of DRB alleles appears to have arisen largely by point mutations in the β-pleated sheets and by frequent exchange of fixed sequence motifs in the α-helical portion. Pairs of alleles differing only at amino acid position b86 by an exchange of valine to glycine are present in Aotus, as in humans. Essential amino acid residues contributing to MHC DR peptide binding pockets number 1 and 4 are conserved or semiconserved between HLA-DR and Aona-DRB molecules, indicating a capacity to bind similar peptide repertoires. These results support fully our using Aotus monkeys as an animal model for evaluation of future subunit vaccine candidates. Received: 10 August 1999 / Revised: 11 October 1999     

The broad-spectrum antiviral ribonucleoside ribavirin is an RNA virus mutagen

The ribonucleoside analog ribavirin (1-beta-D-ribofuranosyl-1,2, 4-triazole-3-carboxamide) shows antiviral activity against a variety of RNA viruses and is used in combination with interferon-alpha to treat hepatitis C virus infection. Here we show in vitro use of ribavirin triphosphate by a model viral RNA polymerase, poliovirus 3Dpol. Ribavirin incorporation is mutagenic, as it templates incorporation of cytidine and uridine with equal efficiency. Ribavirin reduces infectious poliovirus production to as little as 0. 00001% in cell culture. The antiviral activity of ribavirin correlates directly with its mutagenic activity. These data indicate that ribavirin forces the virus into 'error catastrophe'. Thus, mutagenic ribonucleosides may represent an important class of anti-RNA virus agents.     

Spermine cytotoxicity to human colon carcinoma-derived cells (CaCo-2)

Spermine is a constituent of all vertebrate cells. Nevertheless, it exerts toxic effects if it accumulates in cells. Spermine is a natural substrate of the FAD-dependent polyamine oxidase, a constitutive enzyme of many cell types. It has been reported that the toxicity of spermine was enhanced if polyamine oxidase was inhibited. We were interested to examine spermine toxicity to human colon carcinoma-derived CaCo-2 cells because, in contrast to most tumor cell lines, CaCo-2 cells undergo differentiation, which is paralleled by changes in polyamine metabolism. CaCo-2 cells were remarkably resistant to spermine accumulation, presumably because spermine is degraded by polyamine oxidase at a rate sufficient to provide spermidine for the maintenance of growth. Inactivation of polyamine oxidase increased the sensitivity to spermine. A major reason for the enhanced spermine cytotoxicity at low polyamine oxidase activity is presumably the profound depletion of spermidine, and the consequent occupation of spermidine binding sites by spermine. Hydrogen peroxide and the aldehydes 3-aminopropanal and 3-acetamidopropanal, the products of polyamine oxidase-catalyzed splitting of spermine and N ¹-acetylspermine, contribute little to spermine cytotoxicity. Activation of caspase by spermine was insignificant, and the formation of DNA ladders, another indicator of apoptotic cell death, could not be observed. Thus it appears that cell death due to excessive accumulation of spermine in CaCo-2 cells was mainly nonapoptotic. The content of brush border membranes did not change between days 6 and 8 after seeding, and it was not affected by exposure of the cells to spermine. However, the activities of alkaline phosphatase, sucrase, and aminopeptidase in nontreated cells were considerably enhanced during this period, but remained low if cells were exposed to spermine. These changes appear to indicate that differentiation is prevented by intoxication with spermine, although other explanations cannot be excluded. This revised version was published online in July 2006 with corrections to the Cover Date.     

Specificity of RNA Binding by CPEB: Requirement for RNA Recognition Motifs and a Novel Zinc Finger

CPEB is an RNA binding protein that interacts with the maturation-type cytoplasmic polyadenylation element (CPE) (consensus UUUUUAU) to promote polyadenylation and translational activation of maternal mRNAs in Xenopus laevis. CPEB, which is conserved from mammals to invertebrates, is composed of three regions: an amino-terminal portion with no obvious functional motif, two RNA recognition motifs (RRMs), and a cysteine-histidine region that is reminiscent of a zinc finger. In this study, we investigated the physical properties of CPEB required for RNA binding. CPEB can interact with RNA as a monomer, and phosphorylation, which modifies the protein during oocyte maturation, has little effect on RNA binding. Deletion mutations of CPEB have been overexpressed in Escherichia coli and used in a series of RNA gel shift experiments. Although a full-length and a truncated CPEB that lacks 139 amino-terminal amino acids bind CPE-containing RNA avidly, proteins that have had either RRM deleted bind RNA much less efficiently. CPEB that has had the cysteine-histidine region deleted has no detectable capacity to bind RNA. Single alanine substitutions of specific cysteine or histidine residues within this region also abolish RNA binding, pointing to the importance of this highly conserved domain of the protein. Chelation of metal ions by 1,10-phenanthroline inhibits the ability of CPEB to bind RNA; however, RNA binding is restored if the reaction is supplemented with zinc. CPEB also binds other metals such as cobalt and cadmium, but these destroy RNA binding. These data indicate that the RRMs and a zinc finger region of CPEB are essential for RNA binding.     

Costs and Epidemiological Changes of Chronic Diseases: Implications and Challenges for Health Systems

Background

The need to integrate economic and epidemiological aspects in the clinical perspective leads to a proposal for the analysis of health disparities and to an evaluation of the health services and of the new challenges which are now being faced by health system reforms in middle income countries.

Objective

To identify the epidemiological changes, the demand for health services and economic burden from chronic diseases (diabetes and hypertension) in a middle income county.

Methods

We conducted longitudinal analyses of costs and epidemiological changes for diabetes and hypertension in the Mexican health system. The study population included both the insured and uninsured populations. The cost-evaluation method was used, based on the instrumentation and consensus techniques. To estimate the epidemiological changes and financial consequences for 2014–2016, six models were constructed according to the Box-Jenkins technique, using confidence intervals of 95%, and the Box-Pierce test.

Results

Regarding epidemiological changes expected in both diseases for 2014 vs. 2016, an increase is expected, although results predict a greater increase for diabetes, 8–12% in all three studied institutions, (p < .05). Indeed, in the case of diabetes, the increase was 41469 cases for uninsured population (SSA) and 65737 for the insured population (IMSS and ISSSTE). On hypertension cases the increase was 38109 for uninsured vs 62895 for insured. Costs in US$ ranged from $699 to $748 for annual case management per patient in the case of diabetes, and from $485 to $622 in patients with hypertension. Comparing financial consequences of health services required by insured and uninsured populations, the greater increase (23%) will be for the insured population (p < .05). The financial requirements of both diseases will amount to 19.5% of the total budget for the uninsured and 12.5% for the insured population.

Conclusions

If the risk factors and the different health care models remain as they currently are, the economic impact of expected epidemiological changes on the social security system will be particularly strong. Another relevant challenge is the appearance of internal competition in the use and allocation of financial resources with programs for other chronic and infectious diseases.     

Developing a Workflow to Identify Inconsistencies in Volunteered Geographic Information: A Phenological Case Study

Recent improvements in online information communication and mobile location-aware technologies have led to the production of large volumes of volunteered geographic information. Widespread, large-scale efforts by volunteers to collect data can inform and drive scientific advances in diverse fields, including ecology and climatology. Traditional workflows to check the quality of such volunteered information can be costly and time consuming as they heavily rely on human interventions. However, identifying factors that can influence data quality, such as inconsistency, is crucial when these data are used in modeling and decision-making frameworks. Recently developed workflows use simple statistical approaches that assume that the majority of the information is consistent. However, this assumption is not generalizable, and ignores underlying geographic and environmental contextual variability that may explain apparent inconsistencies. Here we describe an automated workflow to check inconsistency based on the availability of contextual environmental information for sampling locations. The workflow consists of three steps: (1) dimensionality reduction to facilitate further analysis and interpretation of results, (2) model-based clustering to group observations according to their contextual conditions, and (3) identification of inconsistent observations within each cluster. The workflow was applied to volunteered observations of flowering in common and cloned lilac plants (Syringa vulgaris and Syringa x chinensis) in the United States for the period 1980 to 2013. About 97% of the observations for both common and cloned lilacs were flagged as consistent, indicating that volunteers provided reliable information for this case study. Relative to the original dataset, the exclusion of inconsistent observations changed the apparent rate of change in lilac bloom dates by two days per decade, indicating the importance of inconsistency checking as a key step in data quality assessment for volunteered geographic information. Initiatives that leverage volunteered geographic information can adapt this workflow to improve the quality of their datasets and the robustness of their scientific analyses.     

Ubiquitination pathway as a target to develop abiotic stress tolerance in rice

Abiotic stresses may result in significant losses in rice grain productivity. Protein regulation by the ubiquitin/proteasome system has been studied as a target mechanism to optimize adaptation and survival strategies of plants to different environmental stresses. This article aimed at highlighting recent discoveries about the roles ubiquitination may play in the exposure of rice plants to different abiotic stresses, enabling the development of modified plants tolerant to stress. Responses provided by the ubiquitination process include the regulation of the stomatal opening, phytohormones levels, protein stabilization, cell membrane integrity, meristematic cell maintenance, as well as the regulation of reactive oxygen species and heavy metals levels. It is noticeable that ubiquitination is a potential means for developing abiotic stress tolerant plants, being an excellent alternative to rice (and other cultures) improvement programs.     

Host‐associated differentiation in a highly polyphagous,sexually reproducing insect herbivore

Insect herbivores may undergo genetic divergence on their host plants through host‐associated differentiation (HAD). Much of what we know about HAD involves insect species with narrow host ranges (i.e., specialists) that spend part or all their life cycle inside their hosts, and/or reproduce asexually (e.g., parthenogenetic insects), all of which are thought to facilitate HAD. However, sexually reproducing polyphagous insects can also exhibit HAD. Few sexually reproducing insects have been tested for HAD, and when they have insects from only a handful of potential host‐plant populations have been tested, making it difficult to predict how common HAD is when one considers the entire species' host range. This question is particularly relevant when considering insect pests, as host‐associated populations may differ in traits relevant to their control. Here, we tested for HAD in a cotton (Gossypium hirsutum) pest, the cotton fleahopper (CFH) (Pseudatomoscelis seriatus), a sexually reproducing, highly polyphagous hemipteran insect. A previous study detected one incidence of HAD among three of its host plants. We used Amplified fragment length polymorphism (AFLP) markers to assess HAD in CFH collected from an expanded array of 13 host‐plant species belonging to seven families. Overall, four genetically distinct populations were found. One genetically distinct genotype was exclusively associated with one of the host‐plant species while the other three were observed across more than one host‐plant species. The relatively low degree of HAD in CFH compared to the pea aphid, another hemipteran insect, stresses the likely importance of sexual recombination as a factor increasing the likelihood of HAD.