Phylogenetic diversification of immunoglobulin genes and the antibody repertoire

Immunoglobulins are encoded by a large multigene system that undergoes somatic rearrangement and additional genetic change during the development of immunoglobulin-producing cells. Inducible antibody and antibody-like responses are found in all vertebrates. However, immunoglobulin possessing disulfide-bonded heavy and light chains and domain-type organization has been described only in representatives of the jawed vertebrates. High degrees of nucleotide and predicted amino acid sequence identity are evident when the segmental elements that constitute the immunoglobulin gene loci in phylogenetically divergent vertebrates are compared. However, the organization of gene loci and the manner in which the independent elements recombine (and diversify) vary markedly among different taxa. One striking pattern of gene organization is the "cluster type" that appears to be restricted to the chondrichthyes (cartilaginous fishes) and limits segmental rearrangement to closely linked elements. This type of gene organization is associated with both heavy- and light-chain gene loci. In some cases, the clusters are "joined" or "partially joined" in the germ line, in effect predetermining or partially predetermining, respectively, the encoded specificities (the assumption being that these are expressed) of the individual loci. By relating the sequences of transcribed gene products to their respective germ-line genes, it is evident that, in some cases, joined-type genes are expressed. This raises a question about the existence and/or nature of allelic exclusion in these species. The extensive variation in gene organization found throughout the vertebrate species may relate directly to the role of intersegmental (V<==>D<==>J) distances in the commitment of the individual antibody-producing cell to a particular genetic specificity. Thus, the evolution of this locus, perhaps more so than that of others, may reflect the interrelationships between genetic organization and function.      

The Ontogeny of Vocal Sequences: Insights from a Newborn Wild Chimpanzee (Pan troglodytes schweinfurthii)

International Journal of Primatology - Observations of early vocal behaviours in non-human primates (hereafter primates) are important for direct comparisons between human and primate vocal...     

Feeding ecology and dietary differences between blue monkey (Cercopithecus mitis stuhlmanni Matschie) groups in logged and unlogged forest, Budongo Forest Reserve, Uganda

Several studies have investigated the effects of logging on primate population density, and attempted to relate density differences to changes in vegetation composition. As population density in some forest primates may be considerably influenced by dietary quality, it is important to understand how the effects of vegetation changes commonly associated with logging influence primate feeding ecology. Results are presented from a study carried out in the Budongo Forest Reserve in Uganda to investigate differences in blue monkey (Cercopithecus mitis stuhlmanni) feeding ecology in forest blocks with different logging history. Dietary composition differed between logged and unlogged forest, with a higher proportion of unripe fruit consumed in logged forest. By contrast, the proportion of young leaves, invertebrates and seeds in the diet was higher in unlogged forest. Variations in the intake of fruit was also higher in unlogged forest, but feeding patterns on other dietary items were more selective. These differences in diet reflect differences in availability of different categories of food items, as determined by tree species composition, abundance and plant phenological patterns. The observed differences between feeding ecology in logged and unlogged forest are discussed in relation to primate feeding ecology and habitat composition in Budongo.     

What can we learn from noncoding regions of similarity between genomes?

Background  

In addition to known protein-coding genes, large amounts of apparently non-coding sequence are conserved between the human and mouse genomes. It seems reasonable to assume that these conserved regions are more likely to contain functional elements than less-conserved portions of the genome.     

An interlaboratory comparison of physiological and genetic properties of four Saccharomyces cerevisiae strains

To select a Saccharomyces cerevisiae reference strain amenable to experimental techniques used in (molecular) genetic, physiological and biochemical engineering research, a variety of properties were studied in four diploid, prototrophic laboratory strains. The following parameters were investigated: 1) maximum specific growth rate in shake-flask cultures; 2) biomass yields on glucose during growth on defined media in batch cultures and steady-state chemostat cultures under controlled conditions with respect to pH and dissolved oxygen concentration; 3) the critical specific growth rate above which aerobic fermentation becomes apparent in glucose-limited accelerostat cultures; 4) sporulation and mating efficiency; and 5) transformation efficiency via the lithium-acetate, bicine, and electroporation methods. On the basis of physiological as well as genetic properties, strains from the CEN.PK family were selected as a platform for cell-factory research on the stoichiometry and kinetics of growth and product formation.     

Antenatal Syphilis Screening Using Point-Of-Care Testing in Low- and Middle-Income Countries in Asia and Latin America: A Cost-Effectiveness Analysis

BackgroundUntreated syphilis in pregnancy is associated with adverse clinical outcomes to the infant. In low- and middle-income countries in Asia and Latin America, 20%-30% of women are not tested for syphilis during pregnancy. We evaluated the cost-effectiveness of increasing the coverage for antenatal syphilis screening in 11 Asian and 20 Latin American countries, using a point-of-care immunochromatographic strip (ICS) test.MethodsThe decision analytical cost-effectiveness models reported incremental costs per disability-adjusted life years (DALYs) averted from the perspectives of the national health care payer. Clinical outcomes were stillbirths, neonatal deaths, and congenital syphilis. DALYs were computed using WHO disability weights. Costs included the ICS test, three injections of benzathine penicillin, and nurse wages. Country-specific inputs included the antenatal prevalence of syphilis and the proportion of women in the antenatal care setting that are screened for syphilis infection as reported in the 2014 WHO baseline report on global sexually transmitted infection surveillance. Country-specific data on the annual number of live births, proportion of women with at least one antenatal care visit, and per capita gross national income were also included in the model.ResultsThe incremental cost/DALY averted of syphilis screening is US$53 (range: US$10-US$332; Prob<1*per capita GDP=99.71%) in Asia and US$60 (range: US$5-US$225; Prob<1*per capita GDP=99.77%) in Latin America. Universal screening may reduce the annual number of stillbirths by 20,344 and 4,270, neonatal deaths by 8,201 and 1,721, cases of congenital syphilis by 10,952 and 2,298, and avert 925,039 and 197,454 DALYs in the aggregate Asian and Latin American panel, respectively.ConclusionAntenatal syphilis screening is highly cost-effective in all the 11 Asian and 20 Latin American countries assessed. Our findings support the decision to expand syphilis screening in countries with currently low screening rates or continue national syphilis screening programs in countries with high rates.     

“I Spent a Full Month Bleeding,I Thought I Was Going to Die…” A Qualitative Study of Experiences of Women Using Modern Contraception in Wakiso District,Uganda

Introduction

There is high unmet need for family planning (FP) in Uganda as well as high contraceptive discontinuation rates. These contribute to the high fertility rates that in part are due to unplanned pregnancies. There are gaps in knowledge about experiences that couples go through while using contraceptives in their lives. This study explored women’s experiences during the course of their contraceptive use.

Methods

We conducted a qualitative study involving 30 women who had used modern contraception for at least one year in Wakiso district, central Uganda. We used in-depth interviews to obtain their personal accounts. Index women were approached through health officers at four health centres in the district. All ethical approvals and informed consent were obtained. We used conventional content analysis; identifying codes through open coding, on which basis categories were developed and grouped into overarching themes.

Results

Women’s accounts were summarised in the following themes: negative experiences with modern contraceptive use, motivation to continue using FP in spite of these negative experiences, the role of influential people, and discontinuation of use. Negative accounts dominated the experiences of most women but they expressed strong desire to continue using modern contraception even amidst all challenges. Health workers emerged as the most influential people that played a vital role in women’s decisions.

Conclusion

Varied negative experiences with modern contraception and misperceptions exist amidst a determination to continue use. Partner engagement, health service strengthening to improve side effects management and health worker skills, and engaging older women that have successfully used contraception as community champions, are potential strategies to support women’s contraceptive decisions.