Genetic networks regulated by ASYMMETRIC LEAVES1 (AS1) and AS2 in leaf development in Arabidopsis thaliana: KNOX genes control five morphological events

The asymmetric leaves 1 ( as1 ) and as2 mutants of Arabidopsis thaliana exhibit pleiotropic phenotypes. Expression of a number of genes, including three class-1 KNOTTED -like homeobox ( KNOX ) genes ( BP , KNAT2 and KNAT6 ) and ETTIN / ARF3 , is enhanced in these mutants. In the present study, we attempted to identify the phenotypic features of as1 and as2 mutants that were generated by ectopic expression of KNOX genes, using multiple loss-of-function mutations of KNOX genes as well as as1 and as2 . Our results revealed that the ectopic expression of class-1 KNOX genes resulted in reductions in the sizes of leaves, reductions in the size of sepals and petals, the formation of a less prominent midvein, the repression of adventitious root formation and late flowering. Our results also revealed that the reduction in leaf size and late flowering were caused by the repression, by KNOX genes, of a gibberellin (GA) pathway in as1 and as2 plants. The formation of a less prominent midvein and the repression of adventitious root formation were not, however, related to the GA pathway. The asymmetric formation of leaf lobes, the lower complexity of higher-ordered veins, and the elevated frequency of adventitious shoot formation on leaves of as1 and as2 plants were not rescued by multiple mutations in KNOX genes. These features must, therefore, be controlled by other genes in which expression is enhanced in the as1 and as2 mutants.     

Interaction of Allium sativum leaf agglutinin with midgut brush border membrane vesicles proteins and its stability in Helicoverpa armigera

Allium sativum leaf agglutinin (ASAL) binds to several proteins in the midgut of Helicoverpa armigera and causes toxicity. Most of these were glycosylated. Six ASAL-binding proteins were selected for identification. PMF and MS/MS data showed their similarity with midgut aminopeptidase APN2, polycalins and alkaline phosphatase of H. armigera, cadherin-N protein (partial AGAP009726-PA) of Acyrthosiphon pisum, cytochrome P450 (CYP315A1) of Manduca sexta and alkaline phosphatase of Heliothis virescens. Some of the ASAL-binding midgut proteins were similar to the larval receptors responsible for the binding of δ-endotoxin proteins of Bacillus thuringiensis. Galanthus nivalis agglutinin also interacted with most of the ASAL-binding proteins. The ASAL showed resistance to midgut proteases and was detected in the larval hemolymph and excreta. Immunohistochemical staining revealed the presence of ASAL in the body tissue also.     

Ozone‐induced reductions in below‐ground biomass: an anatomical approach in potato

Potato plants were grown in open‐top chambers under three ozone concentrations during two complete cropping seasons (93 and 77 d in 2004 and 2005, respectively). The effects of chronic exposure to ozone on leaf anatomy, cell ultrastructure and crop yield were studied. Severe cell damage was found, even at ambient ozone levels, mainly affecting the spongy parenchyma and areas near the stomata. Damage to the cell wall caused loss of cell contact, and loss of turgor pressure due to tonoplast disintegration, contributed to cell collapse. Phloem sieve plates were obstructed by callose accumulation, and damaged mesophyll cells increased their starch stores. Tuber yield fell sharply (24–44%), due to the biggest tubers becoming smaller, which affected commercial yield. These anatomical findings show the mechanisms of ozone effect on assimilate partitioning, and thus crop yield decrease, in potato. Further implications of ozone causing reductions in below‐ground biomass are also discussed.     

Interaction of the N-terminal segment of HCV protein NS5A with model membranes

We have identified a membrane-active region in the HCV NS5A protein by performing an exhaustive study of membrane rupture induced by a NS5A-derived peptide library on model membranes having different phospholipid compositions. We report the identification in NS5A of a highly membranotropic region located at the suggested membrane association domain of the protein. We report the binding and interaction with model membranes of two peptides patterned after this segment, peptides 1A and 1B, derived from the strains 1a_H77 and 1b_HC-4J respectively. We show that they insert into phospholipid membranes, interact with them, and are located in a shallow position in the membrane. The NS5A region where this segment resides might have an essential role in the membrane replication and/or assembly of the viral particle through the modulation of the replication complex, and consequently, directly implicated in the HCV life cycle.     

Cotranslational Folding Increases GFP Folding Yield

Protein sequences evolved to fold in cells, including cotranslational folding of nascent polypeptide chains during their synthesis by the ribosome. The vectorial (N- to C-terminal) nature of cotranslational folding constrains the conformations of the nascent polypeptide chain in a manner not experienced by full-length chains diluted out of denaturant. We are still discovering to what extent these constraints affect later, posttranslational folding events. Here we directly address whether conformational constraints imposed by cotranslational folding affect the partitioning between productive folding to the native structure versus aggregation. We isolated polyribosomes from Escherichia coli cells expressing GFP, analyzed the nascent chain length distribution to determine the number of nascent chains that were long enough to fold to the native fluorescent structure, and calculated the folding yield for these nascent chains upon ribosome release versus the folding yield of an equivalent concentration of full-length, chemically denatured GFP polypeptide chains. We find that the yield of native fluorescent GFP is dramatically higher upon ribosome release of nascent chains versus dilution of full-length chains from denaturant. For kinetically trapped native structures such as GFP, folding correctly the first time, immediately after release from the ribosome, can lead to lifelong population of the native structure, as opposed to aggregation.     

Resource use efficiency in urban and peri-urban sheep, goat and cattle enterprises

Urban livestock husbandry receives growing attention given the increasing urban demand for livestock products. At the same time, little is known about the resource use efficiency in urban livestock enterprises and eventual negative externalities. In livestock production, feeds are an important resource whose nutrients are transformed into products (meat and milk) to generate financial return to the producer. The lack of knowledge on nutrient supply through feed might lead to oversupply with severe environmental impacts. In Niamey, a typical West African city and capital of the Republic of Niger, urban livestock production is constrained by feed scarcity, especially during the dry season. Here, the issue of resource use efficiency was studied in 13 representative and differently managed sheep/goat and cattle enterprises characterized by high and low feed inputs, respectively, during a period of 28 months. Nitrogen (N), phosphorus (P) and potassium (K) inflows into each farm through livestock feeds and outflows through manure were determined using a semi-structured questionnaire; interviews were accompanied by regular weighing of feed supplied and dung produced. Live weight gain (LWG) and efficiency of conversion of total feed dry matter offered (kg TDMO/kg LWG) were computed along with nutrient balances (NBs) per metabolic body mass (kg0.75). NBs (per kg0.75/day) in the high-input (HI) sheep/goat enterprises were +1762.4 mg N, +127.2 mg P and +1363.5 mg K and were significantly greater (P < 0.05) than those in low-input (LI) units (+69.1 mg N, -98.3 mg P and +16.5 mg K). In HI cattle enterprises, daily balances averaged +454.1 mg N, +40.1 mg P and +341.8 mg K compared to +34.4 mg N, -9.0 mg P and +68.3 mg K (P > 0.05) in LI cattle systems. All systems were characterized by poor conversion efficiencies of offered feed, which ranged from 13.5 to 46.1 kg TDMO/kg LWG in cattle and from 15.7 to 43.4 kg TDMO/kg LWG in sheep/goats. LWG in HI sheep/goats was 53 g/day in the rainy season, 86 g/day in the hot dry season and 104 g/day in the cool dry season, while HI cattle lost 79 g/day in the hot dry season and gained 121 g/day and 92 g/day in the cool dry and rainy seasons, respectively. The data indicate that there is nutrient wasting and scope for improvement of feeding strategies in Niamey's livestock enterprises, which might also decrease nutrient losses to the urban environment.     

Shoot anatomy and secretory structures in Hypericum species (Hypericaceae)

The anatomy and ultrastructure of internodes, leaves and petals were compared in Hypericum elegans, H. inodorum, H. olympicum, H. forrestii and two genotypes of H. perforatum. Internode anatomy was variable between species with respect to the structure of the cortical and pith parenchyma, including the presence of secretory reservoirs. Also, the secondary growth was more extensive in shrubs, i.e. H. inodorum and H. forrestii. In leaves, phloem secretory reservoirs were formed in all species, mesophyll secretory reservoirs were absent only in H. elegans and internal nodules were present only in H. elegans and H. perforatum. The petals differed between species in the mesophyll structure and the occurrence and location of secretory structures. The phloem secretory reservoirs lacked sheaths, whereas these were distinct in the mesophyll reservoirs. Other ultrastructural traits of the reservoirs were similar in all the species studied, with the exception of the leucoplast ultrastructure. In internal nodules, the inner cells vs. sheath cells differed in the number of vesicles and other membranous structures and plastid ultrastructure. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 70–86.     

Influence of castration-induced testosterone and estradiol deficiency on obesity and glucose metabolism in male Göttingen minipigs

Low testosterone and estradiol concentrations are predictive for the development of the metabolic syndrome in men and women, respectively. The aim of this study was to investigate the influence of sex hormone deficiency on food intake, body weight, body composition and glucose metabolism in male Göttingen minipigs.Five adult male Göttingen minipigs were studied before castration (pre-cast), 10-18 days (post-cast 1) and 10-11 weeks (post-cast 2) after castration. Parameters of interest were food intake, body weight, body fat percentage and sex hormone concentrations. Furthermore glucose tolerance, glucagon suppression, insulin resistance, beta cell function and disposition index were evaluated by oral and intravenous glucose tolerance tests.Castration led to almost complete disappearance of circulating testosterone and estradiol and secondarily to increased food intake, body weight and body fat percentage. Ten-eighteen days sex hormone deficiency (post-cast 1) did not significantly change any of the investigated metabolic parameters compared to pre-cast levels. Ten weeks after castration (post-cast 2) significant insulin resistance, glucose intolerance and hyperglucagonemia was found, and the beta cell function and the disposition index both were decreased.In conclusion, castration-induced sex hormone deficiency in male Göttingen minipigs results in hyperphagia, obesity and disturbed glucose metabolism, which are some of the features typical for the human metabolic syndrome.