Increasing Exercise Intensity Reduces Heterogeneity of Glucose Uptake in Human Skeletal Muscles

Proper muscle activation is a key feature of survival in different tasks in daily life as well as sports performance, but can be impaired in elderly and in diseases. Therefore it is also clinically important to better understand the phenomenon that can be elucidated in humans non-invasively by positron emission tomography (PET) with measurements of spatial heterogeneity of glucose uptake within and among muscles during exercise. We studied six healthy young men during 35 minutes of cycling at relative intensities of 30% (low), 55% (moderate), and 75% (high) of maximal oxygen consumption on three separate days. Glucose uptake in the quadriceps femoris muscle group (QF), the main force producing muscle group in recreational cycling, and its four individual muscles, was directly measured using PET and 18F-fluoro-deoxy-glucose. Within-muscle heterogeneity was determined by calculating the coefficient of variance (CV) of glucose uptake in PET image voxels within the muscle of interest, and among-muscles heterogeneity of glucose uptake in QF was expressed as CV of the mean glucose uptake values of its separate muscles. With increasing intensity, within-muscle heterogeneity decreased in the entire QF as well as within its all four individual parts. Among-muscles glucose uptake heterogeneity also decreased with increasing intensity. However, mean glucose uptake was consistently lower and heterogeneity higher in rectus femoris muscle that is known to consist of the highest percentage of fast twitch type II fibers, compared to the other three QF muscles. In conclusion, these results show that in addition to increased contribution of distinct muscle parts, with increases in exercise intensity there is also an enhanced recruitment of muscle fibers within all of the four heads of QF, despite established differences in muscle-part specific fiber type distributions. Glucose uptake heterogeneity may serve as a useful non-invasive tool to elucidate muscle activation in aging and diseased populations.     

Impact of host cell line choice on glycan profile

Protein glycosylation is post-translational modification (PTM) which is important for pharmacokinetics and immunogenicity of recombinant glycoprotein therapeutics. As a result of variations in monosaccharide composition, glycosidic linkages and glycan branching, glycosylation introduces considerable complexity and heterogeneity to therapeutics. The host cell line used to produce the glycoprotein has a strong influence on the glycosylation because different host systems may express varying repertoire of glycosylation enzymes and transporters that contributes to specificity and heterogeneity in glycosylation profiles. In this review, we discuss the types of host cell lines currently used for recombinant therapeutic production, their glycosylation potential and the resultant impact on glycoprotein properties. In addition, we compare the reported glycosylation profiles of four recombinant glycoproteins: immunoglobulin G (IgG), coagulation factor VII (FVII), erythropoietin (EPO) and alpha-1 antitrypsin (A1AT) produced in different mammalian cells to establish the influence of mammalian host cell lines on glycosylation.     

Genome‐wide Linkage Analysis of Multiple Metabolic Factors: Evidence of Genetic Heterogeneity

The metabolic syndrome is a highly complex disease and has become one of the major public‐health challenges worldwide. We sought to identify genetic loci with potential influence on multiple metabolic factors in a white population in Beaver Dam, Wisconsin, and to explore the possibility of genetic heterogeneity by family history of diabetes (FHD). Three metabolic factors were generated using principal‐component factor analysis, and they represented: (i) glycemia, (ii) blood pressure, and (iii) combined (BMI, high‐density lipoprotein (HDL) cholesterol, and serum uric acid) factors. Multipoint model‐free linkage analysis of these factors with 385 microsatellite markers was performed on 1,055 sib‐pairs, using Haseman–Elston regression. Genome‐wide suggestive evidence of linkage was found at 30 cM on chromosome 22q (empirical P (P_e) = 0.0002) for the glycemia factor, at 188–191 cM on chromosome 1q (P_e = 0.0007) for the blood pressure factor, and at 82 cM on chromosome 17q (P_e = 0.0007) for the combined factor. Subset analyses of the families by FHD showed evidence of genetic heterogeneity, with divergent linkage signals in the subsets on at least four chromosomes. We found evidence of genetic heterogeneity by FHD for the three metabolic factors. The results also confirmed findings of previous studies that mapped components of the metabolic syndrome to a chromosome 1q region.     

Alloreactive cloned T cell lines. VII. Comparison of the kinetics of IL 2 release stimulated by alloantigen or Con A

Injection of poly(Glu50Tyr50)(GT) into B10.BR (H-2k) mice induces GT-specific suppressor T cells and a T cell-derived suppressor factor (TsF1), which in turn induces a second-order suppressor T cell (TS2). In the present study, we show that B10.BR GT-TSF1 is composed of separate I-Jk and idiotype-bearing chains linked by disulfide bond(s). Functional suppressive activity requires both chains to be in association. Neither chain alone can induce TS2, indicating that both chains must be seen in association and suggesting a single cellular target for the two chains. Experiments designed to interchange I-J-bearing chains of GT-TSF1 derived from different H-2 haplotypes indicate that only the homologous I-J and idiotype-bearing chains can reassociate into a suppressive moiety. These experiments may imply heterogeneity of I-J region gene products.     

Environmental heterogeneity,species diversity and co‐existence at different spatial scales

The positive relationship between spatial environmental heterogeneity and species diversity is a widely accepted concept, generally associated with niche limitation. However, niche limitation cannot account for negative heterogeneity–diversity relationships (HDR) revealed in several case studies. Here we explore how HDR varies at different spatial scales and provide novel theories for small‐scale species co‐existence that explain both positive and negative HDR. At large spatial scales of heterogeneity (e.g. landscape level), different communities co‐exist, promoting large regional species pool size and resulting in positive HDR. At smaller scales within communities, species co‐existence can be enhanced by increasing the number of different patches, as predicted by the niche limitation theory, or alternatively, restrained by heterogeneity. We conducted meta‐regressions for experimental and observational HDR studies, and found that negative HDRs are significantly more common at smaller spatial scales. We propose three theories to account for niche limitation at small spatial scales. (1) Microfragmentation theory: with increasing spatial heterogeneity, large homogeneous patches lose area and become isolated, which in turn restrains the establishment of new plant individuals and populations, thus reducing species richness. (2) Heterogeneity confounded by mean: when heterogeneity occurs at spatial scales smaller than the size of individual plants, which forage through the patches, species diversity can be either positively or negatively affected by a change in the mean of an environmental factor. (3) Heterogeneity as a separate niche axis: the ability of species to tolerate heterogeneity at spatial scales smaller than plant size varies, affecting HDR. We conclude that processes other than niche limitation can affect the relationship between heterogeneity and diversity.     

Seasonality in the incidence of cervical carcinoma in teenagers and young adults in Northern England, 1968-2005

Infection with human papillomavirus is an established risk factor for cervical carcinoma. However, the role of other environmental factors is less well established. To further investigate whether other agents may be involved, the authors have analyzed seasonal variation in cervical cancer with respect to month of birth and separately month of diagnosis. All 85 cases diagnosed in 15-24-yr-olds during the period 1968-2005 were extracted from the specialist population-based Northern Region Young Persons' Malignant Disease Registry. The chi-square heterogeneity test was used to assess overall nonuniform variation in month of birth and separately month of diagnosis. Poisson regression analysis was used to fit sinusoidal (harmonic) models to the data using month of birth and month of diagnosis in separate models. Based on month of birth, there was statistically significant heterogeneity (p=.03) and a significant sinusoidal pattern, with an incidence peak involving births in the autumn months (p=.03). Based on month of diagnosis, there was marginally significant heterogeneity (p=.06). The evidence of seasonal variation around time of birth for cervical carcinoma is highly novel and suggests possible early etiological involvement of environmental factors.     

Intra- and Intergenomic Variation of Ribosomal RNA Operons in Concurrent Alteromonas macleodii Strains

Biodiversity estimates based on ribosomal operon sequence diversity rely on the premise that a sequence is characteristic of a single specific taxon or operational taxonomic unit (OTU). Here, we have studied the sequence diversity of 14 ribosomal RNA operons (rrn) contained in the genomes of two isolates (five operons in each genome) and four metagenomic fosmids, all from the same seawater sample. Complete sequencing of the isolate genomes and the fosmids establish that they represent strains of the same species, Alteromonas macleodii, with average nucleotide identity (ANI) values >97 %. Nonetheless, we observed high levels of intragenomic heterogeneity (i.e., variability between operons of a single genome) affecting multiple regions of the 16S and 23S rRNA genes as well as the internally transcribed spacer 1 (ITS-1) region. Furthermore, the ribosomal operons exhibited intergenomic heterogeneity (i.e., variability between operons located in separate genomes) in each of these regions, compounding the variability. Our data reveal the extensive heterogeneity observed in natural populations of A. macleodii at a single point in time and support the idea that distinct lineages of A. macleodii exist in the deep Mediterranean. These findings highlight the potential of rRNA fingerprinting methods to misrepresent species diversity while simultaneously failing to recognize the ecological significance of individual strains.     

The heterogeneity of rat kidney lysosomes revealed by immunoelectron microscopic staining for cathepsins B and H

The heterogeneity of lysosomes was studied by analyzing the immunostaining behavior of cathepsins B and H in rat kidney proximal tubule cells. Rat kidneys were fixed by perfusion and embedded in Lowicryl K4M. A protein A-gold technique was applied to serial sections and a double labeling technique to conventional sections. By analyzing the immunostaining behavior of cathepsins B and H in the same lysosomes which were cut into separate sections, four types of lysosomes were found: Type 1 positive for both proteinases; type 2 strongly positive for cathepsin B, but weakly or negative for cathepsin H; type 3 strongly positive for cathepsin H, but weakly or negative for cathepsin B; and type 4 negative for both proteinases. The double labeling by two different sizes of the protein A-gold probes showed these four types of lysosomes. The results indicate that there exists the lysosomal heterogeneity of the proteinase content in the kidney proximal tubule cells.     

The heterogeneity of rat kidney lysosomes revealed by immunoelectron microscopic staining for cathepsins B and H

Summary The heterogeneity of lysosomes was studied by analyzing the immunostaining behavior of cathepsins B and H in rat kidney proximal tubule cells. Rat kidneys were fixed by perfusion and embedded in Lowicryl K4M. A protein A-gold technique was applied to serial sections and a double labeling technique to conventional sections. By analyzing the immunostaining behavior of cathepsins B and H in the same lysosomes which were cut into separate sections, four types of lysosomes were found: Type 1 positive for both proteinases; type 2 strongly positive for cathepsin B, but weakly or negative for cathepsin H; type 3 strongly positive for cathepsin H, but weakly or negative for cathepsin B; and type 4 negative for both proteinases. The double labeling by two different sizes of the protein A-gold probes showed these four types of lysosomes. The results indicate that there exists the lysosomal heterogeneity of the proteinase content in the kidney proximal tubule cells.     

Serological and structural features of Hafnia alvei lipopolysaccharides containing d-3-hydroxybutyric acid

Abstract The serological heterogeneity of Hafnia alvei lipopolysaccharides from strains ATCC 13337, 1187, 1221, 114/60, 1211 and 1216, that contain d -3-hydroxybutyric acid, was analyzed by rocket immunoelectrophoresis, immunoblotting and passive hemagglutination. The significance of d -3-hydroxybutyric acid component for their cross-reactivity has been discussed. The results obtained allowed us to place four H. alvei strains (ATCC 13337, 1187, 1221 and 114/60) in one serotype (A) and to consider two other strains (1211 and 1216) as separate serotypes (B and C, respectively).     

Analysis of active renin heterogeneity

Active renin is a heterogeneous enzyme that can be separated into multiple forms with high-resolution isoelectric focusing. The isoelectric heterogeneity may result from differences in glycosylation between the different forms. In order to determine the relationship between active renin heterogeneity and differences in composition or attachment of oligosaccharides, two separate experiments were performed: (i) Tunicamycin, which interferes with normal glycosylation processing, increased the proportion of relatively basic renin forms secreted into the incubation media by rat renal cortical slices. (ii) Endoglycosidase F, which enzymatically removes carbohydrate from some classes of glycoprotein, similarly increased the proportion of relatively basic forms when incubated with active human recombinant renin. In addition, further studies with inhibitors of human renin activity revealed that the heterogeneous renin forms were similarly inhibited by two separate renin inhibitors. These results are consistent with the hypothesis that renin isoelectric heterogeneity is due in part to differences in carbohydrate moiety attachment and that the heterogeneity of renin does not influence access of direct renin inhibitors to the active site of renin.     

Mitochondrial DNA Variation in Northwestern Bering Sea Walleye Pollock, Theragra chalcogramma (Pallas)

Genetic variability of the highly valuable gadid species, walleye pollock, Theragra chalcogramma (Pallas 1811), from five spatially separated northwestern Bering Sea areas (Ozernoi Bay, Olutorskyi Bay, Koryak shelf, Navarin region, and Anadyr Gulf) was investigated. Haplotype diversity within the samples ranged from 0.8788±0.0393 to 0.9436±0.0162. Nucleotide diversity within the samples ranged from 0.0108 to 0.0127. Nucleotide diversity among the regional collections ranged from 0% to 0.18%. Walleye pollock from the Anadyr Gulf appeared genetically separate from the other four samples in a clustering of genetic distances. Total heterogeneity among all five samples was significant, while there was no heterogeneity among the four samples excluding that from the Anadyr Gulf. Pair-wise comparisons using tests for heterogeneity and F_st supported the dendrogram of genetic distances in that only the collection from the Anadyr Gulf was significantly different from the others. The observed pattern of genetic differentiation among walleye pollock from the northwestern Bering Sea presumably emerged as a result of a population of the species subdividing in the northernmost part of its geographic range, though further analysis is needed to verify this supposition.     

Characterization of the cysteinyl-containing peptides of the gamma subunit of coupling factor 1

The cysteinyl peptides of the gamma subunit of chloroplast coupling factor 1 (CF1) have been analyzed by high performance liquid chromatography. Analysis of the reduced enzyme alkylated with 4-vinylpyridine showed that the gamma subunit contains four cysteinyl residues. Two of these residues are involved in a disulfide linkage in CF1 either in solution or bound to washed thylakoid membranes. Two free sulfhydryls, one that is readily attacked by alkylating reagents and another that is less reactive, were also detected. Each of these four cysteinyl residues is present in a separate tryptic peptide derived from the gamma subunit. These results show that 4-vinylpyridine is an excellent reagent for the analysis of cysteinyl-containing peptides and support our analyses of the roles of cysteinyl residues in the gamma subunit in ATP synthesis and hydrolysis.     

Effects of search experience in a resource-heterogeneous environment on the oviposition decisions of the seed beetle, Callosobruchus maculatus (F.)

Abstract.  1. This study investigates how female seed beetles, Callosobruchus maculatus , distribute their eggs on various-sized seeds when the size of seed was varied during the egg-laying period.
2. Beetles were allowed to lay eggs on one of three arrays of 64 adzuki beans ( Vigna angularis ). Each array contained four size classes of seed, ranging from small (5.0–5.5 mm diameter) to large (6.5–7.0 mm), but differed in how they were distributed within the environment. In the most heterogeneous condition (the 64-patch design), the four sizes were interspersed, while in the least heterogeneous condition (the four-patch design) they were grouped into four separate blocks. Thus, a beetle exploring the 64-patch design would frequently encounter all four seed sizes, whereas a beetle exploring the four-patch design would only rarely encounter a change in bean size.
3. Beetles experiencing greater seed size heterogeneity were more likely to lay eggs on larger seeds, whereas those in the blocked condition were more likely to oviposit on small seeds. Beetle responses to seed size heterogeneity suggest that the degree of preference for large seeds depends on a female's recent experience.
4. Female beetles exhibited size discrimination throughout their egg-laying process; however, there was a trade-off between seed size and egg discrimination (i.e. avoiding those seeds already containing developing eggs) in response to the change in fitness gained from either laying on larger seeds or lower egg-load seeds during the egg-laying process.
5. Our model provides the first evidence that evolving seed size discrimination ability is adaptive for the seed beetle with egg-discrimination ability.     

Distribution patterns of four Orthoptera species in relation to microhabitat heterogeneity in an ecotonal area

Microhabitat heterogeneity is considered to be one of the main factors affecting the structure and diversity of natural communities. This study evaluated: (i) whether it is possible to associate the distribution of four orthopteran species with small-scale spatial microhabitat heterogeneity based on floristic composition; and (ii) whether interspecific differences exist in microhabitat was among the different orthopteran species over a gradient of vegetation succession induced by abandonment of meadows. Orthoptera and plant species were sampled on 72 plots across an ecotonal area on Monte Bondone in the Southern Italian Alps. Microhabitats were identified based on grassland and undergrowth vegetation composition and by classifying sample plots using cluster analysis. Eight microhabitats were identified, each corresponding to a separate successional stage, and microhabitat use by each species was assessed. The distribution of orthopteran species revealed a different use of microhabitats. Species also had differing patterns of distribution, and a shift in distribution occurred following a change in microhabitat structure caused by mowing. The importance of the maintenance of a mosaic of microhabitats, with differently managed adjacent areas is discussed.     

Does increased baseline ventilation heterogeneity following chest wall strapping predispose to airway hyperresponsiveness?

Baseline ventilation heterogeneity is associated with airway hyperresponsiveness (AHR) in asthma; however, it is unknown whether increased baseline ventilation heterogeneity leads to AHR or both are independent effects of similar disease pathophysiology. Reducing functional residual capacity (FRC) in healthy subjects increases baseline ventilation heterogeneity and airway responsiveness, but the relationship between the two is unclear. The aim was to determine whether an increase in baseline ventilation heterogeneity due to a reduction in FRC correlated with the increase in response to methacholine. In 13 healthy male subjects, ventilation heterogeneity was measured by multiple-breath N(2) washout before a cumulative high-dose (0.79-200 μmol) methacholine challenge. On a separate day, the protocol was performed with chest wall strapping (CWS) to reduce FRC. Indexes of ventilation heterogeneity in the convection-dependent (Scond) and diffusion-convection-dependent (Sacin) airways were calculated from the multiple-breath N(2) washout. CWS decreased FRC by 15.6 ± 2.7% (P < 0.0001). CWS increased the percent fall in forced expiratory volume in 1 s during bronchial challenge (P = 0.006), and the magnitude of this effect was independently determined by the effect of CWS on Sacin and FRC (r(adj)(2) = 0.55, P = 0.02). This suggests that changes in baseline ventilation heterogeneity in healthy subjects are sufficient to increase airway responsiveness, independent of the presence of disease pathology.     

Temporal and Microgeographic Variation in Allozyme Frequencies in a Natural Population of DROSOPHILA BUZZATII

Temporal variation in allozyme frequencies at six loci was studied by making monthly collections over 4 yr in one population of the cactophilic species Drosophila buzzatii. Ten sites were defined within the study locality, and for all temporal samples, separate collections were made at each of these sites. Population structure over microgeographic space and changes in population structure over time were analyzed using F-statistic estimators, and multivariate analyses of allele and genotype frequencies with environmental variables were carried out. Allele frequencies showed significant variation over time, although there were no clear cyclical or seasonal patterns. A biplot analysis of allele frequencies over seasons within years and over years showed clear discrimination among years by alleles at four loci. During the 4 yr, three alleles showed directional changes which were associated with directional changes in environmental variables. Significant associations with one or more environmental variables were found for allele frequencies at every locus and for both expected and observed heterozygosities (except those for Est-1 and Est-2). Thus, variation in allele frequencies over time cannot be attributed solely to drift. Significant linkage disequilibria were detected among three loci (Est-2, Hex and Aldox), but there was no evidence for spatial or temporal patterns. The F-statistic analyses showed significant differentiation among months within years for all loci, but the statistic used (coancestry) was heterogeneous among loci. Estimates of F (inbreeding) for all loci were significantly different from zero, with the loci in four groups, Adh-1 (negative), Pgm(small positive), Est-2 and Hex (intermediate) and Est-1 and Aldox (high positive). The correlation of genes within individuals within populations (f) for each locus in each month by site sample differed among loci, as did the (f) for each locus in each month by site sample differed among loci, as did the patterns of change in f over time (seasons). Heterogeneity in the F-statistic estimates indicates that natural selection is directly or indirectly affecting allele and genotype frequencies at some loci. However, the F-statistic analyses showed essentially no microgeographic structure (i.e., among sites), although there was significant heterogeneity in allele frequencies among flies emerging from individual rots. Thus, microspatial heterogeneity probably is most important at the level of individual rots, and coupled with habitat selection, it could be a major factor promoting diversifying selection and the maintenance of polymorphism.(ABSTRACT TRUNCATED AT 400 WORDS)     

Molecular heterogeneity of pro-atrial natriuretic factor

Analysis by two-dimensional gel electrophoresis and Western blotting of the atrial natriuretic factor (ANF) content of atrial granules revealed the presence of at least 15 immunoreactive spots whose molecular mass distribution ranged from 16.8 to 35 kDa and their pI values from 5.12 to 5.98. About 90% of the immunoreactive ANF material was contained within four spots (spot 1: 34.8 kDa, pI 5.67; spot 5: 16.8 kDa, pI 5.50; spot 6: 16.8 kDa, pI 5.67; spot 7: 16.8 kDa, pI 5.98). Investigation of the molecular nature of spot 1 indicated that it is a dimer of pro-ANF since it possesses the same immunoreactivity, the same charge, double its mass, and can be converted with dithiothreitol into a 16.8-kDa pro-ANF form. Alkaline phosphatase and protein kinase A treatments indicated that spots 5, 6, and 7 are probably not phosphorylated forms of pro-ANF. Carboxypeptide A and B treatments in conjunction with amino acid analysis suggested that spot 7 is ANF-(1-128); spot 6, the major one, ANF-(1-126); and spot 5, ANF-(1-123) or ANF-(1-124). Water deprivation or morphine injection, two maneuvers which are known to influence ANF secretion and atrial ANF content, failed to affect the molecular heterogeneity of pro-ANF except for spot 1. The formation of the dimer appeared to be time-dependent. These results emphasize the heterogeneity of the pro-ANF molecule stored in atrial granules. We suggest that this heterogeneity may be due, in part, to the action of some proteases, such as carboxypeptidase E or a tripeptidyl carboxyhydrolase.     

Use of SSR fragment length homozygotes for orangutan systematics

The use of simple sequence repeat (SSR) loci lacking length polymorphisms among their alleles (defined here as homozygotes) in systemtic studies has thus far been largely ignored due to their apparent lack of genetic heterogeneity. However, in this paper we show that point mutations, insertions, and deletions within SSR loci of identical size can be highly informative for population genetic and evolutionary studies. Our preliminary study of the von Willebrand factor (vWF) locus shows that there is a significant level of divergence among the Bornean Orangutans which implies that present orangutan subbopulations in Borneo are genetically isolated from each other. However, our findings do not confirm that the Bornean and Sumatran Orangutans form two separate clades.