The rabbit alpha-like globin gene cluster is polymorphic both in the sizes of BamHI fragments and in the numbers of duplicated sets of genes

The alpha-like globin gene cluster in rabbits contains embryonic zeta- globin genes, an adult alpha-globin gene, and theta-globin genes of undetermined function. The basic arrangement of genes, deduced from analysis of cloned DNA fragments, is 5'-zeta 0-zeta 1-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3'. However, the pattern of restriction fragments containing zeta- and theta-globin genes varies among individual rabbits. Analysis of BamHI fragments of genomic DNA from 24 New Zealand white rabbits revealed eight different patterns of fragments containing zeta-globin genes. The large BamHI fragments containing genes zeta 0 and zeta 1 are polymorphic in length, whereas a 1.9-kb fragment containing the zeta 2 gene and the 3.5-kb fragment containing the zeta 3 gene do not vary in size. In contrast to this constancy in the size of the restriction fragments, the copy number of the zeta 2 and zeta 3 genes does vary among different rabbits. No length polymorphism was detected in the BamHI fragments containing the theta-globin genes, but again the copy number varies for restriction fragments containing the theta 2 gene. The alpha 1- and theta 1-globin genes are located in a nonpolymorphic 7.2-kb BamHI fragment. The combined data from hybridization with both zeta and theta probes shows that the BamHI cleavage pattern does not vary within the region 5'-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3', but the pattern genomic blot-hybridization patterns for the progeny of parental rabbits with different zeta-globin gene patterns shows that the polymorphic patterns are inherited in a Mendelian fashion. Two different haplotypes have been mapped based on the genomic blot-hybridization data. The variation in the alpha-like globin gene cluster in the rabbit population results both from differences in the copy number of the duplication block containing the zeta-zeta-theta gene set and from the presence or absence of polymorphic BamHI sites.      

Assignment of orthologous relationships among mammalian alpha-globin genes by examining flanking regions reveals a rapid rate of evolution

In order to study the relationships among mammalian alpha-globin genes, we have determined the sequence of the 3' flanking region of the human alpha 1 globin gene and have made pairwise comparisons between sequenced alpha-globin genes. The flanking regions were examined in detail because sequence matches in these regions could be interpreted with the least complication from the gene duplications and conversions that have occurred frequently in mammalian alpha-like globin gene clusters. We found good matches between the flanking regions of human alpha 1 and rabbit alpha 1, human psi alpha 1 and goat I alpha, human alpha 2 and goat II alpha, and horse alpha 1 and goat II alpha. These matches were used to align the alpha-globin genes in gene clusters from different mammals. This alignment shows that genes at equivalent positions in the gene clusters of different mammals can be functional or nonfunctional, depending on whether they corrected against a functional alpha-globin gene in recent evolutionary history. The number of alpha-globin genes (including pseudogenes) appears to differ among species, although highly divergent pseudogenes may not have been detected in all species examined. Although matching sequences could be found in interspecies comparisons of the flanking regions of alpha- globin genes, these matches are not as extensive as those found in the flanking regions of mammalian beta-like globin genes. This observation suggests that the noncoding sequences in the mammalian alpha-globin gene clusters are evolving at a faster rate than those in the beta-like globin gene clusters. The proposed faster rate of evolution fits with the poor conservation of the genetic linkage map around alpha-globin gene clusters when compared to that of the beta-like globin gene clusters. Analysis of the 3' flanking regions of alpha-globin genes has revealed a conserved sequence approximately 100-150 bp 3' to the polyadenylation site; this sequence may be involved in the expression or regulation of alpha-globin genes.      

A comparison of the long-term morbidity following deep circumflex iliac and fibula free flaps for reconstruction following head and neck cancer

Composite free tissue transfer has an established role in head and neck oncology for the reconstruction of the bony defect following tumor ablation, and while donor-site morbidity is variably reported, there is little consensus on the most favorable donor site. The fibula and deep circumflex iliac artery have distinct advantages in terms of the volume and length of bone in mandibular reconstruction. Few studies have compared their donor-site morbidity. The aim of this study was to compare the fibula and deep circumflex iliac artery flaps using a review of the case notes and cross-sectional review of patients attending a research clinic for validated orthopedic examination and completion of health-related quality-of-life questionnaires. Between February of 1993 and May of 2001, 44 fibula free flaps and 73 deep circumflex iliac artery free flaps were performed. Ninety-nine case notes and 36 patients were available for review of donor-site morbidity. Sixteen patients with fibula flaps and 20 patients with deep circumflex iliac artery flaps took part in the clinical examination component of the study, which was composed of a clinical examination by an orthopedic surgeon using the American Orthopedic Foot and Ankle Society ankle scoring system and the Harris hip scoring system, and two patient-completed questionnaires, the University of Washington Questionnaire and the Hospital Anxiety and Depression Scale. Subjective and objective markers of morbidity related to both flaps were similar in most parameters. However, fibula flaps were associated with more problems with donor-site healing, reduced power, and sensation. Poor orthopedic scores for both flaps were associated with notably poor scores on the University of Washington Questionnaire and the Hospital Anxiety and Depression Scale. The study would suggest that both deep circumflex iliac artery and fibula donor sites result in an acceptable and comparable morbidity for most patients, but in cases in which significant donor-site morbidity is encountered, health-related quality of life is significantly compromised.     

Out of Africa and back again: nested cladistic analysis of human Y chromosome variation

We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544 individuals from Africa, Asia, Europe, Oceania, and the New World. Phylogenetic analyses of these nine sites resulted in a tree for 10 distinct Y haplotypes with a coalescence time of approximately 150,000 years. The 10 haplotypes were unevenly distributed among human populations: 5 were restricted to a particular continent, 2 were shared between Africa and Europe, 1 was present only in the Old World, and 2 were found in all geographic regions surveyed. The ancestral haplotype was limited to African populations. Random permutation procedures revealed statistically significant patterns of geographical structuring of this paternal genetic variation. The results of a nested cladistic analysis indicated that these geographical associations arose through a combination of processes, including restricted, recurrent gene flow (isolation by distance) and range expansions. We inferred that one of the oldest events in the nested cladistic analysis was a range expansion out of Africa which resulted in the complete replacement of Y chromosomes throughout the Old World, a finding consistent with many versions of the Out of Africa Replacement Model. A second and more recent range expansion brought Asian Y chromosomes back to Africa without replacing the indigenous African male gene pool. Thus, the previously observed high levels of Y chromosomal genetic diversity in Africa may be due in part to bidirectional population movements. Finally, a comparison of our results with those from nested cladistic analyses of human mtDNA and beta-globin data revealed different patterns of inferences for males and females concerning the relative roles of population history (range expansions) and population structure (recurrent gene flow), thereby adding a new sex-specific component to models of human evolution.      

Bacterial production of free fatty acids from freshwater macroalgal cellulose

The predominant strategy for using algae to produce biofuels relies on the overproduction of lipids in microalgae with subsequent conversion to biodiesel (methyl-esters) or green diesel (alkanes). Conditions that both optimize algal growth and lipid accumulation rarely overlap, and differences in growth rates can lead to wild species outcompeting the desired lipid-rich strains. Here, we demonstrate an alternative strategy in which cellulose contained in the cell walls of multicellular algae is used as a feedstock for cultivating biofuel-producing microorganisms. Cellulose was extracted from an environmental sample of Cladophora glomerata-dominated periphyton that was collected from Lake Mendota, WI, USA. The resulting cellulose cake was hydrolyzed by commercial enzymes to release fermentable glucose. The hydrolysis mixture was used to formulate an undefined medium that was able to support the growth, without supplementation, of a free fatty acid (FFA)-overproducing strain of Escherichia coli (Lennen et. al 2010). To maximize free fatty acid production from glucose, an isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible vector was constructed to express the Umbellularia californica acyl-acyl carrier protein (ACP) thioesterase. Thioesterase expression was optimized by inducing cultures with 50 μM IPTG. Cell density and FFA titers from cultures grown on algae-based media reached 50% of those (～90 μg/mL FFA) cultures grown on rich Luria-Bertani broth supplemented with 0.2% glucose. In comparison, cultures grown in two media based on AFEX-pretreated corn stover generated tenfold less FFA than cultures grown in algae-based media. This study demonstrates that macroalgal cellulose is a potential carbon source for the production of biofuels or other microbially synthesized compounds.     

Recognition of Childhood Overweight during Health Supervision Visits: Does BMI Help Pediatricians?

Objective: To assess, in diverse pediatric practices, the frequency of overweight/obesity (OW/OB) identification during health supervision visits and its association with BMI curve use. Research Methods and Procedures: Pediatricians in public and private practice in St. Louis, MO, participated in a study of the care of chronic conditions during health supervision visits. Requested information from 30 visits per pediatrician of children 6 to 17 years of age included the visit note, the growth chart, and a one‐page questionnaire about patient demographics and visit content. Pediatricians indicated the presence and discussion of common chronic conditions, including OW/OB. Identification was compared with patient BMI category, and associations between identification and patient and visit characteristics, including BMI curve use, were examined. Results: Twenty‐one (40%) of contacted pediatricians returned information from 557 visits. Pediatricians identified OW/OB in 27% of children with a BMI at the 85th to 94th percentile and 86% of children with a BMI at or above the 95th percentile. Identification was higher in adolescents but was not associated with patient sex or race, practice setting, insurance type, or visit length. Only 41% of growth charts were current, and 6.1% had BMI plotted. BMI plotting was associated with OW/OB identification when the BMI was at the 85th to 94th percentile but not when the BMI was at or above the 95th percentile. After controlling for BMI percentile, OW/OB identification was significantly associated with diet counseling (odds ratio, 7.46; 95% confidence interval, 3.42 to 16.24) and exercise counseling (odds ratio, 5.57; 95% confidence interval, 2.61 to 11.90). Discussion: Despite low BMI curve use, pediatricians recognized most overweight/obese children with a BMI at or above the 95th percentile. BMI plotting may increase recognition in mildly overweight children.