Views of the public about Snacktivity™: a small changes approach to promoting physical activity and reducing sedentary behaviour.

BACKGROUND: Many people do not meet the recommended health guidance of participation in a minimum of 150-300 min of moderate intensity physical activity per week, often promoted as at least 30 min of physical activity on 5 days of the week. This is concerning and highlights the importance of finding innovative ways to help people to be physically active each day. Snacktivity™ is a novel approach that aims to encourage people to do small, 2-5 min bouts of physical activity 'snacks' throughout the whole day, such that they achieve at least 150 min of moderate intensity activity per week. However, before it can be recommended, there is a need to explore whether the concept is acceptable to the public. METHODS: A survey to assess the views of the public about Snacktivity™ was distributed to adult patients registered at six general practices in the West Midlands, UK and to health care employees in the same region. RESULTS: A total of 5989 surveys were sent to patients, of which 558 were returned (9.3%). A further 166 surveys were completed by health care employees. A total of 85% of respondents liked the Snacktivity™ concept. The flexibility of the approach was highly rated. A high proportion of participants (61%) reported that the ability to self-monitor their behaviour would help them to do Snacktivity™ throughout their day. Physically inactive participants perceived that Snacktivity™ would help to increase their physical activity, more than those who were physically active (OR = 0.41, 95% CI: 0.25-0.67). Approximately 90% of respondents perceived that Snacktivity™ was easy to do on a non-working day compared to 60% on a working day. Aerobic activity 'snacks' were preferred to those which were strength based. CONCLUSIONS: The Snacktivity™ approach to promoting physical activity was viewed positively by the public and interventions to test the merits of such an approach now need to be developed and tested in a variety of everyday contexts.

A limited LCA of bio-adipic acid: manufacturing the nylon-6,6 precursor adipic acid using the benzoic acid degradation pathway from different feedstocks.

A limited life cycle assessment (LCA) was performed on a combined biological and chemical process for the production of adipic acid, which was compared to the traditional petrochemical process. The LCA comprises the biological conversion of the aromatic feedstocks benzoic acid, impure aromatics, toluene, or phenol from lignin to cis, cis-muconic acid, which is subsequently converted to adipic acid through hydrogenation. Apart from the impact of usage of petrochemical and biomass-based feedstocks, the environmental impact of the final concentration of cis, cis-muconic acid in the fermentation broth was studied using 1.85% and 4.26% cis, cis-muconic acid. The LCA focused on the cumulative energy demand (CED), cumulative exergy demand (CExD), and the CO(2) equivalent (CO(2) eq) emission, with CO(2) and N(2) O measured separately. The highest calculated reduction potential of CED and CExD were achieved using phenol, which reduced the CED by 29% and 57% with 1.85% and 4.26% cis, cis-muconic acid, respectively. A decrease in the CO(2) eq emission was especially achieved when the N(2) O emission in the combined biological and chemical process was restricted. At 4.26% cis, cis-muconic acid, the different carbon backbone feedstocks contributed to an optimized reduction of CO(2) eq emissions ranging from 14.0 to 17.4 ton CO(2) eq/ton adipic acid. The bulk of the bioprocessing energy intensity is attributed to the hydrogenation reactor, which has a high environmental impact and a direct relationship with the product concentration in the broth.

Conversion of polyhydroxyalkanoates to methyl crotonate using whole cells.

Isolated polyhydroxyalkanoates (PHA) can be used to produce biobased bulk chemicals. However, isolation is complex and costly. To circumvent this, whole cells containing PHA may be used. Here, PHA containing 3-hydroxybutyrate and small amounts of 3-hydroxyvalerate was produced from wastewater and used in the conversion of the 3-hydroxybutyrate monomer to methyl crotonate. Due to the increased complexity of whole cell reaction mixtures compared to pure PHA, the effect of 3-hydroxyvalerate content, magnesium salts and water content was studied in order to evaluate the need for downstream processing. A water content up to 20% and the presence of 3-hydroxyvalerate have no influence on the conversion of the 3-hydroxybutyrate to methyl crotonate. The presence of Mg(2+)-ions resulted either in an increased yield or in byproduct formation depending on the counter ion. Overall, it is possible to bypass a major part of the downstream processing of PHA for the production of biobased chemicals.

Sequence homology of nuclear and mitochondrial DNAs of different yeasts.

1. Both nuclear and mtDNA of four different yeasts show approximately 10% homology as measured by DNA-DNA filter hybridization. These homologous sequences are mainly attributable to the ribosomal cistrons. 2. Melting curve analysis shows that the heterologous mitochondrial DNA-DNA hybrids contain several times more mismatching than the nuclear DNA-DNA hybrids. 3. DNA-rRNA hybridization shows that the sequences of the ribosomal cistrons in both the nuclear and the mitochondrial genome have been conserved during evolution. 4. However, melting curve analysis of the DNA-RNA hybrids shows that the sequence of the nuclear ribosomal cistrons have undergone considerable fewer nucleotide substitutions than their mitochondrial counterparts. 5. The results suggest that the mitochondrial ribosomal cistrons have evolved more rapidly than the nuclear cistrons. This is discussed in the light of theories on the rat of molecular evolutin.

Expression of chicken hepatic type I and type III iodothyronine deiodinases during embryonic development.

In embryonic chicken liver (ECL) two types of iodothyronine deiodinases are expressed: D1 and D3. D1 catalyzes the activation as well as the inactivation of thyroid hormone by outer and inner ring deiodination, respectively. D3 only catalyzes inner ring deiodination. D1 and D3 have been cloned from mammals and amphibians and shown to contain a selenocysteine (Sec) residue. We characterized chicken D1 and D3 complementary DNAs (cDNAs) and studied the expression of hepatic D1 and D3 messenger RNAs (mRNAs) during embryonic development. Oligonucleotides based on two amino acid sequences strongly conserved in the different deiodinases (NFGSCTSecP and YIEEAH) were used for reverse transcription-PCR of poly(A+) RNA isolated from embryonic day 17 (E17) chicken liver, resulting in the amplification of two 117-bp DNA fragments. Screening of an E17 chicken liver cDNA library with these probes led to the isolation of two cDNA clones, ECL1711 and ECL1715. The ECL1711 clone was 1360 bp long and lacked a translation start site. Sequence alignment showed that it shared highest sequence identity with D1s from other vertebrates and that the coding sequence probably lacked the first five nucleotides. An ATG start codon was engineered by site-directed mutagenesis, generating a mutant (ECL1711M) with four additional codons (coding for MGTR). The open reading frame of ECL1711M coded for a 249-amino acid protein showing 58-62% identity with mammalian D1s. An in-frame TGA codon was located at position 127, which is translated as Sec in the presence ofa Sec insertion sequence (SECIS) identified in the 3'-untranslated region. Enzyme activity expressed in COS-1 cells by transfection with ECL1711M showed the same catalytic, substrate, and inhibitor specificities as native chicken D1. The ECL1715 clone was 1366 bp long and also lacked a translation start site. Sequence alignment showed that it was most homologous with D3 from other species and that the coding sequence lacked approximately the first 46 nucleotides. The deduced amino acid sequence showed 62-72% identity with the D3 sequences from other species, including a putative Sec residue at a corresponding position. The 3'-untranslated region of ECL1715 also contained a SECIS element. These results indicate that ECL1711 and ECL1715 are near-full-length cDNA clones for chicken D1 and D3 selenoproteins, respectively. The ontogeny of D1 and D3 expression in chicken liver was studied between E14 and 1 day after hatching (C1). D1 activity showed a gradual increase from E14 until C1, whereas D1 mRNA level remained relatively constant. D3 activity and mRNA level were highly significantly correlated, showing an increase from E14 to E17 and a strong decrease thereafter. These results suggest that the regulation of chicken hepatic D3 expression during embryonic development occurs predominantly at the pretranslational level.

Characterization of a propylthiouracil-insensitive type I iodothyronine deiodinase.

Mammalian type I iodothyronine deiodinase (D1) activates and inactivates thyroid hormone by outer ring deiodination (ORD) and inner ring deiodination (IRD), respectively, and is potently inhibited by propylthiouracil (PTU). Here we describe the cloning and characterization of a complementary DNA encoding a PTU-insensitive D1 from teleost fish (Oreochromis niloticus, tilapia). This complementary DNA codes for a protein of 248 amino acids, including a putative selenocysteine (Sec) residue, encoded by a TGA triplet, at position 126. The 3' untranslated region contains two putative Sec insertion sequence (SECIS) elements. Recombinant enzyme expressed in COS-1 cells catalyzes both ORD of T4 and rT3 and IRD of T3 and T3 sulfate with the same substrate specificity as native tilapia D1 (tD1), i.e. rT3 >> T4 > T3 sulfate > T3. Native and recombinant tD1 show equally low sensitivities to inhibition by PTU, iodoacetate, and gold thioglucose compared with the potent inhibitions observed with mammalian D1s. Because the residue 2 positions downstream from Sec is Pro in tD1 and in all (PTU-insensitive) type II and type III iodothyronine deiodinases but Ser in all PTU-sensitive D1s, we prepared the Pro128Ser mutant of tD1. The mutant enzyme showed strongly decreased ORD and somewhat increased IRD activity, but was still insensitive to PTU. These results provide new information about the structure-activity relationship of D1 concerning two characteristic properties, i.e. catalysis of both ORD and IRD, and inhibition by PTU.

Cloning and characterization of type III iodothyronine deiodinase from the fish Oreochromis niloticus.

Type III iodothyronine deiodinase (D3) catalyzes the inner ring deiodination (IRD) of T4 and T3 to the inactive metabolites rT3 and 3,3'-diiodothyronine (3,3'-T2), respectively. Here we describe the cloning and characterization of complementary DNA (cDNA) coding for D3 in fish (Oreochromis niloticus, tilapia). This cDNA contains 1478 nucleotides and codes for a protein of 267 amino acids, including a putative selenocysteine (Sec) residue, encoded by a TGA triplet, at position 131. The deduced amino acid sequence shows 57-67% identity with frog, chicken, and mammalian D3, 33-39% identity with frog, fish (Fundulus heteroclitus) and mammalian D2, and 30-35% identity with fish (tilapia), chicken, and mammalian D1. The 3' UTR contains a putative Sec insertion sequence (SECIS) element. Recombinant tilapia D3 (tD3) expressed in COS-1 cells and native tD3 in tilapia brain microsomes show identical catalytic activities, with a strong preference for IRD of T3 (Km approximately 20 nM). IRD of [3,5-125I]T3 by native and recombinant tD3 are equally sensitive to inhibition by substrate analogs (T3 > T4 >> rT3) and inhibitors (gold thioglucose >> iodoacetate > propylthiouracil). Northern analysis using a tD3 riboprobe shows high expression of a 1.6-kb messenger RNA in gill and brain, although D3 activity is much higher in brain than in gill. The characterization of tD3 cDNA provides new information about the structure-activity relationship of iodothyronine deiodinases and an important tool to study the regulation of thyroid hormone bioactivity in fish.

A multistate outbreak of Salmonella enterica Serotype Newport infection linked to mango consumption: impact of water-dip disinfestation technology.

Fresh produce increasingly is recognized as an important source of salmonellosis in the United States. In December 1999, the Centers for Disease Control and Prevention detected a nationwide increase in Salmonella serotype Newport (SN) infections that had occurred during the previous month. SN isolates recovered from patients in this cluster had indistinguishable pulsed-field gel electrophoresis (PFGE) patterns (which identified the outbreak strain), suggesting a common source. Seventy-eight patients from 13 states were infected with the outbreak strain. Fifteen patients were hospitalized; 2 died. Among 28 patients enrolled in the matched case-control study, 14 (50%) reported they ate mangoes in the 5 days before illness onset, compared with 4 (10%) of the control subjects during the same period (matched odds ratio, 21.6; 95% confidence interval, 3.53- infinity; P=.0001). Traceback of the implicated mangoes led to a single Brazilian farm, where we identified hot water treatment as a possible point of contamination; this is a relatively new process to prevent importation of an agricultural pest, the Mediterranean fruit fly. This is the first reported outbreak of salmonellosis implicating mangoes. PFGE was critical to the timely recognition of this nationwide outbreak. This outbreak highlights the potential global health impact of foodborne diseases and newly implemented food processes.

Ontogeny of iodothyronine deiodinases in human liver.

The role of the deiodinases D1, D2, and D3 in the tissue-specific and time-dependent regulation of thyroid hormone bioactivity during fetal development has been investigated in animals but little is known about the ontogeny of these enzymes in humans. We analyzed D1, D2, and D3 activities in liver microsomes from 10 fetuses of 15-20 weeks gestation and from 8 apparently healthy adult tissue transplant donors, and in liver homogenates from 2 fetuses (20 weeks gestation), 5 preterm infants (27-32 weeks gestation), and 13 term infants who survived up to 39 weeks postnatally. D1 activity was determined using 1 microM [3',5'-125I]rT3 as substrate and 10 mM dithiothreitol (DTT) as cofactor, D2 activity using 1 nM [3',5'-125I]T4 and 25 mM DTT in the presence of 1 mM 6-propyl-2-thiouracil (to block D1 activity) and 1 microM T3 (to block D3 activity), and D3 activity using 10 nM [3,5-125I]T3 and 50 mM DTT, by quantitation of the release of 125I. The assays were validated by high performance liquid chromatography of the products, and kinetic analysis [Michaelis-Menten constant (Km) of rT3 for D1: 0.5 microM; Km of T3 for D3: 2 nM]. In liver homogenates, D1 activity was not correlated with age, whereas D3 activity showed a strong negative correlation with age (r -0.84), with high D3 activities in preterm infants and (except in 1 infant of 35 weeks) absent D3 activity in full-term infants. In microsomes, D1 activities amounted to 4.3-60 pmol/min/mg protein in fetal livers and to 170-313 pmol/min/mg protein in adult livers, whereas microsomal D3 activities were 0.15-1.45 pmol/min/mg protein in fetuses and <0.1 pmol/min/mg protein in all but one adult. In the latter sample, D3 activity amounted to 0.36 pmol/min/mg protein. D2 activity was negligible in both fetal and adult livers. These findings indicate high D1 and D3 activities in fetal human liver, and high D1 and mostly absent D3 activities in adult human liver. Therefore, the low serum T3 levels in the human fetus appear to be caused by high hepatic (and placental) D3 activity rather than caused by low hepatic D1 activity. The occasional expression of D3 in adult human liver is intriguing and deserves further investigation.

Acute pretranslational regulation of type III iodothyronine deiodinase by growth hormone and dexamethasone in chicken embryos.

Both growth hormone (GH) and glucocorticoids are regulators of thyroid hormone metabolism in vertebrates. Studies on chicken embryos demonstrated that intravenous (i.v.) injection of chicken GH or glucocorticoids results in increased plasma 3,3',5-triiodothyronine (T3) concentrations, and this through a reduction of hepatic type III iodothyronine deiodinase (D3) activity. The recent cloning of chicken type I iodothyronine deiodinase (D1) and D3 offers the tools to investigate at what level (pre- or posttranslational) this downregulation of D3 occurs. Eighteen day old chicken embryos were injected with either 0.9% NaCl (control), 50 microg dexamethasone (DEX), or 20 microg cGH per animal. Plasma and tissue samples were taken 5, 10, 30, 60, 120, and 240 min post-injection. Plasma T3 and thyroxine (T4) were determined as well as in vitro hepatic D1 and D3 activities. Hepatic D1 and D3 mRNA levels were measured by both Northern analysis and competitive reverse transcription polymerase chain reaction (RT-PCR). Injection of GH or DEX resulted in a significant increase in plasma T3 when compared to controls within 30 min post-injection. This increase remained until the end of the experiment in the DEX-treated group, but not in the GH group. GH administration had no influence on plasma T4 levels, whereas DEX significantly reduced plasma T4 from 30 min onwards. Hepatic D1 activity and D1 mRNA levels showed no changes. Hepatic D3 activity, however, decreased within 10 min after DEX administration and somewhat slower after GH administration (within 30 min). Hepatic D3 activity remained low for the remainder of the experiment in the DEX-treated group, whereas D3 activity gradually returned to control levels in the GH group. This change in hepatic D3 activity was paralleled by the changes in hepatic D3 mRNA levels (r = 0.88, P = 0.0001) as confirmed by both Northern analysis and competitive RT-PCR. In conclusion, these results demonstrate that in embryonic chicken GH and DEX acutely increase plasma T3 levels by decreasing hepatic D3 activity, a decrease that seems to be regulated predominantly at the pretranslational level. These results are also an indication for the short half life (t(1/2)) of the D3 enzyme. The time lag between the effect of GH and DEX on hepatic D3 mRNA may be due to differences in the mechanism of action between both hormones, a subject that needs further investigation.

Prematurity and orgasmic coitus during pregnancy: data on a small sample.

Nineteen mothers of premature infants were interviewed in an attempt to determine a possible relationship between prematurity and orgasmic coitus during pregnancy. Although the limited number of subjects precludes tests of statistical significance and definite conclusions, the findings do suggest possible associations. While there appeared to be no relationship between prematurity and coitus per se during pregnancy, the association of frequent or intense orgasm with prematurity does raise some questions that further investigation might answer. Because of the hazard of prematurity to the subsequent development of the child, further exploration of the possible relationship of prematurity to orgasmic coitus during pregnancy appears warranted.

[Farmers in biotechnology]. / Boeren in biotechnologie.

Biotechnology experienced a stormy development during the past decade. The development of r-DNA technology was of major importance both to the world of science and to that of commerce. Biotechnological developments in the field of veterinary medicine will be commented upon and illustrated in a number of instances in which animals are central. Products which could so far only be obtained from animals, can be isolated from microorganisms on an unlimited scale today. The essential advantages of the biotechnological production of these products will be illustrated in the examples. In addition, it will be possible to use a large number of other products in the field of veterinary science. Both the current results of biotechnological studies and the rapidly increasing prospects for the future will be elaborated.

Effects of thermo-chemical pre-treatment on anaerobic biodegradability and hydrolysis of lignocellulosic biomass.

The effects of different thermo-chemical pre-treatment methods were determined on the biodegradability and hydrolysis rate of lignocellulosic biomass. Three plant species, hay, straw and bracken were thermo-chemically pre-treated with calcium hydroxide, ammonium carbonate and maleic acid. After pre-treatment, the plant material was anaerobically digested in batch bottles under mesophilic conditions for 40 days. From the pre-treatment and subsequent anaerobic digestion experiments, it was concluded that when the lignin content of the plant material is high, thermo-chemical pre-treatments have a positive effect on the biodegradability of the substrate. Calcium hydroxide pre-treatment improves the biodegradability of lignocellulosic biomass, especially for high lignin content substrates, like bracken. Maleic acid generates the highest percentage of dissolved COD during pre-treatment. Ammonium pre-treatment only showed a clear effect on biodegradability for straw.

The organization of genes in yeast mitochondrial DNA II. The physical map of EcoRI and HindII + III fragments.

1. We have isolated large fragments of the mtDNA of the yeast Saccharomyces carlsbergensis and digested these with restriction endonucleases. The digestion products were separated by electrophoresis in agarose gels. 2. Endonucleases EcoRI, HindII + III, HpaI, HindIII and HapII yield 9, 11, 6, 0 and greater than 80 fragments, respectively. 3. By analysis of partial digestion products and by redigesting the fragments obtained with one endonuclease with a second, we have established the order of all EcoRI and HindII + III fragments. The map is circular and its contour length is 22.1 +/- 0.35 mum, in good agreement with earlier estimates of the size of yeast mtDNA, using electron microscopy and renaturation kinetics. 4. A comparison of the fragmentation pattern of mtDNAs from S. carlsbergensis and various strains of Saccharomyces cerevisiae with endonuclease HindII + III suggests that the overall gene order is similar.