Extremely short duration high intensity interval training substantially improves insulin action in young healthy males

Background

Impaired glucose tolerance (IGT) is a prediabetic state. If IGT can be prevented from progressing to overt diabetes, hyperglycemia-related complications can be avoided. The purpose of the present study was to examine whether pioglitazone (ACTOS^®) can prevent progression of IGT to type 2 diabetes mellitus (T2DM) in a prospective randomized, double blind, placebo controlled trial.

Methods/Design

602 IGT subjects were identified with OGTT (2-hour plasma glucose = 140–199 mg/dl). In addition, IGT subjects were required to have FPG = 95–125 mg/dl and at least one other high risk characteristic. Prior to randomization all subjects had measurement of ankle-arm blood pressure, systolic/diastolic blood pressure, HbA_1C, lipid profile and a subset had frequently sampled intravenous glucose tolerance test (FSIVGTT), DEXA, and ultrasound determination of carotid intima-media thickness (IMT). Following this, subjects were randomized to receive pioglitazone (45 mg/day) or placebo, and returned every 2–3 months for FPG determination and annually for OGTT. Repeat carotid IMT measurement was performed at 18 months and study end. Recruitment took place over 24 months, and subjects were followed for an additional 24 months. At study end (48 months) or at time of diagnosis of diabetes the OGTT, FSIVGTT, DEXA, carotid IMT, and all other measurements were repeated. Primary endpoint is conversion of IGT to T2DM based upon FPG ≥ 126 or 2-hour PG ≥ 200 mg/dl. Secondary endpoints include whether pioglitazone can: (i) improve glycemic control (ii) enhance insulin sensitivity, (iii) augment beta cell function, (iv) improve risk factors for cardiovascular disease, (v) cause regression/slow progression of carotid IMT, (vi) revert newly diagnosed diabetes to normal glucose tolerance.

Conclusion

ACT NOW is designed to determine if pioglitazone can prevent/delay progression to diabetes in high risk IGT subjects, and to define the mechanisms (improved insulin sensitivity and/or enhanced beta cell function) via which pioglitazone exerts its beneficial effect on glucose metabolism to prevent/delay onset of T2DM.

Trial Registration

clinical trials.gov identifier: NCT00220961     

Gene flow and range expansion in a mountain‐dwelling passerine with a fragmented distribution

We studied gene flow and bottleneck events in the population history of locally isolated citril finches endemic to European mountains. For the present study, we used two genetic markers with different rates of evolution: a fast evolving mitochondrial marker (ATPase6/8) and a more slowly evolving nuclear marker (02401). Populations north of the Pyrenees showed in general fewer haplotypes and a considerable lower nucleotide and gene diversity than the Iberian populations. Unexpectedly, we found very little genetic variability in the fast evolving mitochondrial marker, arguing for a strong and relatively recent bottleneck event in the species population history. This pattern potentially reflects a sudden decrease of crucial resources during Mid‐Holocene (mountain pine, Scots pine, and black pine) and a subsequent breakdown of the population. The bottleneck could also have been caused or coincide with a selective sweep in the mitochondrion. By contrast, the slowly evolving nuclear marker showed a much higher variability. This marker probably reflects major gene flow along a potential expansion pathway from the Eastern Pyrenees, northwards to the populations of Central Europe, and southwards to the more fragmented populations of central and southern Spain. The population of the Western Pyrenees (Navarra) appears to be cut‐off from this major gene flow and our data indicate a certain degree of partial isolation, probably reflecting more ancient events (e.g. the separation in distinct refuge sites during the last glacial maximum). © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 707–721.     

Mercator: a fast and simple web server for genome scale functional annotation of plant sequence data

Next‐generation technologies generate an overwhelming amount of gene sequence data. Efficient annotation tools are required to make these data amenable to functional genomics analyses. The Mercator pipeline automatically assigns functional terms to protein or nucleotide sequences. It uses the MapMan ‘BIN’ ontology, which is tailored for functional annotation of plant ‘omics’ data. The classification procedure performs parallel sequence searches against reference databases, compiles the results and computes the most likely MapMan BINs for each query. In the current version, the pipeline relies on manually curated reference classifications originating from the three reference organisms (Arabidopsis, Chlamydomonas, rice), various other plant species that have a reviewed SwissProt annotation, and more than 2000 protein domain and family profiles at InterPro, CDD and KOG. Functional annotations predicted by Mercator achieve accuracies above 90% when benchmarked against manual annotation. In addition to mapping files for direct use in the visualization software MapMan, Mercator provides graphical overview charts, detailed annotation information in a convenient web browser interface and a MapMan‐to‐GO translation table to export results as GO terms. Mercator is available free of charge via http://mapman.gabipd.org/web/guest/app/Mercator .     

Lost in translation – a history of systematic confusion and comments on the type species of Squalodon and Patriocetus (Cetacea,Odontoceti)

Abstract: The two odontocete taxa Squalodon grateloupii and Patriocetus ehrlichii, both the type species of their respective genera, have been at the centre of a great deal of taxonomic confusion. Originally regarded to be conspecific, these two taxa have been the subject of a bewildering taxonomic debate lasting for more than a century, which recently led to the suggestion to abandon these widely used names and replace S. grateloupii with the similar, yet independently and later proposed name S. gratelupi as the type species of Squalodon. Here, we attempt to summarise the events leading to the current confused situation in the hope of resolving this issue once and for all and argue that the name Squalodon grateloupii, as originally proposed, should be reinstated.     

Soybean Roots Retain the Seed Urease Isozyme Synthesized during Embryo Development

Roots of young soybean (Glycine max [L.] Merr.) plants (up to 25 days old) contain two distinct urease isozymes, which are separable by hydroxyapatite chromatography. These two urease species (URE1 and URE2) differ in: (a) electrophoretic mobility in native gels, (b) pH dependence, and (c) recognition by a monoclonal antibody specific for the seed (“embryo-specific”) urease. By these parameters root URE1 urease is similar to the abundant embryo-specific urease isozyme, while root URE2 resembles the “ubiquitous” urease which has previously been found in all soybean tissues examined (leaf, embryo, seed coat, and cultured cells). The embryo-specific and ubiquitous urease isozymes are products of the Eu1 and Eu4 structural genes, respectively. Roots of the eu1-sun/eu1-sun genotype, which lacks the embryo-specific urease (i.e. `seed urease-null'), contain no URE1 urease activity. Roots of eu4/eu4, which lacks ubiquitous urease, lack the URE2 (leaflike) urease activity. From these genetic and biochemical criteria, then, we conclude that URE1 and URE2 are the embryo-specific and ubiquitous ureases, respectively. Adventitious roots generated from cuttings of any urease genotype lack URE1 activity. In seedling roots the seedlike (URE1) activity declines during development. Roots of 3-week-old plants contain 5% of the total URE1 activity of the radicle of 4-day-old seedlings, which, in turn, has approximately the same urease activity level as the dormant embryonic axis. The embryo-specific urease incorporates label from [³⁵S]methionine during embryo development but not during germination, indicating that there is no de novo synthesis of the embryo-specific (URE1) urease in the germinating root. We conclude that the seedlike urease (URE1) found in roots of young soybean plants is a remnant of the Eu1-encoded, abundant, embryo-specific urease which accumulates in the embryonic root axis during seed development.     

The inheritance of a urease-null trait in soybeans

Summary Four soybean seed urease nulls (lacking both the activity and antigen of the embryo-specific urease) were intermated and the F₁ and F₂ seed examined for urease activity. Both generations were without urease activity, and the nulls were therefore considered noncomplementing. In crosses of each null line to cultivars homozygous for the allelic, codominantly inherited urease slow or fast isozyme, the F₁ seed expressed the embryo-specific urease isozyme of the urease-expressing parent. A 3 1 segregation for presence and absence of urease was observed in progeny from F₁ and heterozygous F₂ plants. The F₂ and F₃ from fastXnull combinations revealed that urease-positive seed were all phenotypically urease fast, while the same seed from slowXnull combinations showed a segregation of one seed containing a fast urease, either exclusively or in a heterozygous state with the slow isozyme, for every 69 phenotypic slows. Data pooled from F₂ plants which segregate for both the presence (Sun) and absence (Sun) of urease and for the fast (Eu1-b) or slow (Eu1-a) urease allele indicate that the null lesion (Sun) is linked to Eu1 by approximately one map unit. The evidence is consistent with two models: (1) sun is an allele at the embryo-specific urease isozyme locus (Eu1) and that a high degree of exchange (and/or conversion) within the locus results in a 1% recombination frequency between the null trait and urease allozyme; (2) sun is at a distinct locus which is separated by one map unit from the embryo-specific urease isozyme locus (Eu1) upon which it acts in the cis position. Polyadenylated embryo RNA from one of the null lines, PI 229324, exhibited no urease template activity in vitro. Thus, the lack of urease antigen is due to lack of accumulation of translatable urease mRNA. The availability of soybeans lacking seed urease should be extremely useful to breeders as a trait for linkage studies and to geneticists as a transformation marker.Portions of this work were funded by the Illinois and Missouri Agricultural Experiment Stations, the SOHIO-University of Illinois Center of Excellence in Crop Molecular Genetics and Genetic Engineering and by grants PCM-8219652 from the National Science Foundation and USDA/SEA-CRCR-1-1374 from the USDA Competitive Grants Office     

The Product of the LEU-3 Cistron as a Regulatory Element for the Production of the Leucine Biosynthetic Enzymes of Neurospora

A class of intracistronic (or closely linked) partial reversions of leu-3 mutations has been found to be conditionally constitutive with respect to the synthesis of isopropylmalate isomerase (specified by the leu-2 cistron) and beta-isopropylmalate dehydrogenase (specified by the leu-1 cistron), two of the enzymes of leucine biosynthesis in Neurospora. The intermediate level of enzyme production by these leu-3(cc) mutants is independent of the obligatory inducer effector, alpha-isopropylmalate, but dependent upon the presence of the branched-chain amino acids, isoleucine, valine and leucine. The properties of leu-3+, leu-3 and leu-3(cc) in heterokaryons indicate that the transnuclear regulatory activity of the leu-3 product varies specifically as a function of available effector molecules. The information presented suggests that the leu-3 cistron is responsible not only for the production of a "positive" regulatory substance necessary for the expression of the leu-1 and leu-2 cistrons, but that it probably serves also a coordinating role in the expression of many of the genes involved in branched-chain amino acid metabolism.     

Soybean Leaf Urease: A Seed Enzyme?

The soybean (Glycine max L. [Merrill]) var Itachi has 0.2 to 0.3% the urease activity found in developing embryos of a normal line, Prize. The hydroxyurea sensitivity and pH preference of this basal seed urease indicate that it represents a unique enzyme rather than an unusually low level of the normal seed urease. Itachi's seed urease is less sensitive to hydroxyurea inhibition (65-80% inhibition) than Prize seed urease (85-95% inhibition) and is more active at pH 6.1 and 8.8 than at 7.4, whereas the normal seed urease is least active at pH 8.8. Both properties of the basal seed urease are in agreement with the behavior of the leaf urease in extracts of Prize and Itachi leaves.

Neither the leaf urease nor the Itachi seed urease is immuneprecipitated by affinity-purified seed urease antibodies. However, when antibody is in excess, Staphylococcus aureus (Cowan) cell walls containing protein A can precipitate soluble antibody-urease complexes (47-68% of total enzyme) from both leaf (Itachi and Prize) and Itachi seed extracts. Under identical conditions, greater than 90% of Prize seed urease is precipitated. At a 100-fold dilution of antibody, 60% of Prize seed urease is still antibody-complexed while the antibody recognition of the leaf or Itachi seed urease is reduced to 2 to 24%.

The cell culture urease also resembles leaf urease by the criteria of pH preference, hydroxyurea sensitivity, and recognition by seed urease antibodies. In the presence of cycloheximide, nickel stimulates cell culture urease levels (14- or 35-fold depending on assay pH) indicating that cell cultures make a preponderance of apourease under nickel-limiting conditions.

Inasmuch as the ureases of leaf, cell culture, and Itachi seeds are more closely related to each other than they are to the abundant (Prize) seed urease, suggests that the three tissues either contain an identical urease or related tissue-specific isozymes. This second form of urease may have an assimilatory role since it is found in both leaf and seed sink tissues and is required for urea assimilation in cell culture (Polacco 1977 Plant Physiol 59: 827-830).

     

Ubiquitous urease affects soybean susceptibility to fungi

The soybean ubiquitous urease (encoded by GmEu4) is responsible for recycling metabolically derived urea. Additional biological roles have been demonstrated for plant ureases, notably in toxicity to other organisms. However, urease enzymatic activity is not related to its toxicity. The role of GmEu4 in soybean susceptibility to fungi was investigated in this study. A differential expression pattern of GmEu4 was observed in susceptible and resistant genotypes of soybeans over the course of a Phakopsora pachyrhizi infection, especially 24 h after infection. Twenty-nine adult, transgenic soybean plants, representing six independently transformed lines, were obtained. Although the initial aim of this study was to overexpress GmEu4, the transgenic plants exhibited GmEu4 co-suppression and decreased ureolytic activity. The growth of Rhizoctonia solani, Phomopsis sp., and Penicillium herguei in media containing a crude protein extract from either transgenic or non-transgenic leaves was evaluated. The fungal growth was higher in the protein extracts from transgenic urease-deprived plants than in extracts from non-transgenic controls. When infected by P. pachyrhizi uredospores, detached leaves of urease-deprived plants developed a significantly higher number of lesions, pustules and erupted pustules than leaves of non-transgenic plants containing normal levels of the enzyme. The results of the present work show that the soybean plants were more susceptible to fungi in the absence of urease. It was not possible to overexpress active GmEu4. For future work, overexpression of urease fungitoxic peptides could be attempted as an alternative approach.