Expression of the alpha 1-proteinase inhibitor gene family during evolution of the genus Mus

alpha 1-Proteinase inhibitors (alpha 1-PIs) are members of the serpin superfamily of proteinase inhibitors, and are important in the maintenance of homeostasis in a wide variety of animal taxa. Previous studies have shown that in mice (genus Mus), evolution of alpha 1-PIs is characterized by gene amplification, region-specific concerted evolution, and rapid accumulation of amino acid substitutions. The latter occurs primarily in the reactive center, which is the region of the alpha 1-PI molecule that determines the inhibitor's specificity for target proteinases. The P1 residue within the reactive center, which is methionine in so-called orthodox alpha 1-PIs and an amino acid other than methionine in unorthodox alpha 1-PIs, is a primary determinant of inhibitor specificity. In the present study, we find that the expression of mRNAs encoding unorthodox alpha 1-PIs is polymorphic within Mus species, i.e., among individuals or inbred strains. This is in striking contrast to mRNAs that encode orthodox alpha 1-PIs, whose concentrations are relatively invariant. The intraspecies variations in mRNA expression represent polymorphisms in the structure of the alpha 1- PI gene family. The results, taken together with previously described aspects of alpha 1-PI evolution, indicate that the dissimilar levels of polymorphism exhibited by orthodox and unorthodox alpha 1-PIs, which likely have distinct physiological functions, may reflect different levels of selective constraint. The significance of this finding to the evolution of gene families is discussed.      

Dual-acting histone deacetylase-topoisomerase I inhibitors

Current chemotherapy regimens are comprised mostly of single-target drugs which are often plagued by toxic side effects and resistance development. A pharmacological strategy for circumventing these drawbacks could involve designing multivalent ligands that can modulate multiple targets while avoiding the toxicity of a single-targeted agent. Two attractive targets, histone deacetylase (HDAC) and topoisomerase I (Topo I), are cellular modulators that can broadly arrest cancer proliferation through a range of downstream effects. Both are clinically validated targets with multiple inhibitors in therapeutic use. We describe herein the design and synthesis of dual-acting histone deacetylase–topoisomerase I inhibitors. We also show that these dual-acting agents retain activity against HDAC and Topo I, and potently arrest cancer proliferation.     

Does Childhood Diarrhea Influence Cognition Beyond the Diarrhea-Stunting Pathway?

Background

Diarrhea is a leading cause of morbidity among children under 5 years of age in low- and middle-income countries yet the additional effects and sequelae, such as cognitive impairment associated with diarrhea, have not been quantified.

Methods

We quantified the association between diarrhea prevalence and cognitive outcomes while controlling for linear growth in 4 study populations. Cognition was assessed using different methods across sites and was expressed in standardized units. We built linear regression models for each study with standardized cognitive score as the outcome and diarrhea prevalence as the main predictor variable. We then conducted meta-analyses of the regression coefficients to generate pooled estimates of the association between diarrhea prevalence and cognition whilst controlling for anthropometric status and other covariates.

Results

Diarrhea was not a significant predictor of cognitive score in any site in the regression models or in the meta-analyses (Coefficient = 0.07; 95% CI: −0.1, 0.2). The length for age Z- score was negatively related to cognition in all sites (0.18; 95% CI: 0.14, 0.21), with coefficients remarkably similar across sites (Coefficient Range: 0.168–0.186).

Conclusions

We did not demonstrate an association between diarrhea and cognition with stunting included in the model. The links between diarrhea, stunting, and cognition provide additional rationale for accelerating interventions to reduce diarrhea.     

Cryptosporidium species: preliminary descriptions of the prevalence and genotype distribution among school children and hospital patients in the Venda region, Limpopo Province, South Africa

In the present study, the prevalence and species distribution of Cryptosporidium among school children and hospital patients in the Venda region of South Africa was determined. Real time PCR (qPCR) was used for initial screening to detect positive samples while a nested PCR followed by restriction fragment length polymorphism was used to determine the species genotype. From a total of 244 stool samples tested, 44 (18%) had Cryptosporidium with no significant difference (chi(2)=0.04; P=0.841) between samples collected from patients attending hospitals 36/197 (18%) and the samples from primary schools 8/47 (17%). The age groups most affected were those from 2 to 5 years old (28.6%) and 50 to 59 years old (50.0%). Cryptosporidium was detected in 4 (12.5%) of the 31 HIV positive individuals. Fifty-seven percent of the Cryptosporidium positive samples were diarrheic and 26 (59.1%) had elevated lactoferrin content. C. hominis (82%) was more common than C. parvum (18%). This study has demonstrated the high prevalence of Cryptosporidium infections in the Venda region and its implications in causing diarrhea and inflammation.     

Antibodies designed as effective cancer vaccines

Antigen/antibody complexes can efficiently target antigen presenting cells to allow stimulation of the cellular immune response. Due to the difficulty of manufacture and their inherent instability complexes have proved inefficient cancer vaccines. However, anti-idiotypic antibodies mimicking antigens have been shown to stimulate both antibody and T cell responses. The latter are due to T cell mimotopes expressed within the complementarity-determining regions (CDRs) of antibodies that are efficiently presented to dendritic cells in vivo. Based on this observation we have designed a DNA vaccine platform called ImmunoBody™, where cytotoxic T lymphocyte (CTL) and helper T cell epitopes replace CDR regions within the framework of a human IgG1 antibody. The ImmunoBody™ expression system has a number of design features which allow for rapid production of a wide range of vaccines. The CDR regions of the heavy and light chain have been engineered to contain unique restriction endonuclease sites, which can be easily opened, and oligonucleotides encoding the T cell epitopes inserted. The variable and constant regions of the ImmunoBody™ are also flanked by restriction sites, which permit easy exchange of other IgG subtypes. Here we show a range of T cell epitopes can be inserted into the ImmunoBody™ vector and upon immunization these T cell epitopes are efficiently processed and presented to stimulate high frequency helper and CTL responses capable of anti-tumor activity.Key words: DNA vaccines, cancer vaccines, melanoma, CTL, helper T cells     

Synthesis and structure-activity relationship of histone deacetylase (HDAC) inhibitors with triazole-linked cap group

Histone deacetylase (HDAC) inhibition is a recent, clinically validated therapeutic strategy for cancer treatment. Small molecule HDAC inhibitors identified so far fall in to three distinct structural motifs: the zinc-binding group (ZBG), a hydrophobic linker, and a recognition cap group. Here we report the suitability of a 1,2,3-triazole ring as a surface recognition cap group-linking moiety in suberoylanilide hydroxamic acid-like (SAHA-like) HDAC inhibitors. Using “click” chemistry (Huisgen cycloaddition reaction), several triazole-linked SAHA-like hydroxamates were synthesized. Structure–activity relationship revealed that the position of the triazole moiety as well as the identity of the cap group markedly affected the in vitro HDAC inhibition and cell growth inhibitory activities of this class of compounds.     

Glutamine transporter in crypts compensates for loss of villus absorption in bovine cryptosporidiosis

Cryptosporidium parvum infection represents a significant cause of diarrhea in humans and animals. We studied the effect of luminally applied glutamine and the PG synthesis inhibitor indomethacin on NaCl absorption from infected calf ileum in Ussing chambers. Infected ileum displayed a decrease in both mucosal surface area and NaCl absorption. Indomethacin and glutamine or its stable derivative alanyl-glutamine increased the net absorption of Na(+) in infected tissue in an additive manner and to a greater degree than in controls. Immunohistochemical and Western blot studies showed that in control animals neutral amino acid transport system ASC was present in villus and crypts, whereas in infected animals, ASC was strongly present only on the apical border of crypts. These results are consistent with PGs mediating the altered NaCl and water absorption in this infection. Our findings further illustrate that the combined use of a PG synthesis inhibitor and glutamine can fully stimulate Na(+) and Cl(-) absorption despite the severe villous atrophy, an effect associated with increased expression of a Na(+)-dependent amino acid transporter in infected crypts.     

Do orthologous gene phylogenies really support tree-thinking?

Background  

Since Darwin's Origin of Species, reconstructing the Tree of Life has been a goal of evolutionists, and tree-thinking has become a major concept of evolutionary biology. Practically, building the Tree of Life has proven to be tedious. Too few morphological characters are useful for conducting conclusive phylogenetic analyses at the highest taxonomic level. Consequently, molecular sequences (genes, proteins, and genomes) likely constitute the only useful characters for constructing a phylogeny of all life. For this reason, tree-makers expect a lot from gene comparisons. The simultaneous study of the largest number of molecular markers possible is sometimes considered to be one of the best solutions in reconstructing the genealogy of organisms. This conclusion is a direct consequence of tree-thinking: if gene inheritance conforms to a tree-like model of evolution, sampling more of these molecules will provide enough phylogenetic signal to build the Tree of Life. The selection of congruent markers is thus a fundamental step in simultaneous analysis of many genes.