A Study of Gene Expression in the Nematode Resistant Wild Peanut Relative, Arachis stenosperma, in Response to Challenge with Meloidogyne arenaria

Peanut (Arachis hypogaea) is amongst the most important legume crops in the world. One of its main yield constraints is the root-knot nematode Meloidogyne arenaria. A number of wild Arachis species, including A. stenosperma, are resistant to nematodes, and are a potential source of new resistance alleles for cultivated peanut. Using in silico subtraction of ESTs and macroarray analysis, we identified genes differentially expressed in A. stenosperma roots during its resistance response to M. arenaria. The three most differentially expressed genes [Auxin Repressed Protein (AsARP), Cytokinin Oxidase (AsCKX) and Metallothionein Type 2 (AsMET2)] were further analyzed using northern-blot and showed distinct expression profiles in the resistant A. stenosperma and susceptible A. hypogaea, both after, and sometimes even before, challenge with nematodes. Of the three most differentially expressed genes, AsARP and AsCKX are potentially involved in plant hormonal balance, and AsMET2 may be related to the reactive oxygen reaction triggered by the hypersensitive response (HR).     

Seven days of aerobic exercise training improves conduit artery blood flow following glucose ingestion in patients with type 2 diabetes

The vasodilatory effects of insulin account for up to 40% of insulin-mediated glucose disposal; however, insulin-stimulated vasodilation is impaired in individuals with type 2 diabetes, limiting perfusion and delivery of glucose and insulin to target tissues. To determine whether exercise training improves conduit artery blood flow following glucose ingestion, a stimulus for increasing circulating insulin, we assessed femoral blood flow (FBF; Doppler ultrasound) during an oral glucose tolerance test (OGTT; 75 g glucose) in 11 overweight or obese (body mass index, 34 ± 1 kg/m2), sedentary (peak oxygen consumption, 23 ± 1 ml·kg?1·min?1) individuals (53 ± 2 yr) with non-insulin-dependent type 2 diabetes (HbA1c, 6.63 ± 0.18%) before and after 7 days of supervised treadmill and cycling exercise (60 min/day, 60-75% heart rate reserve). Fasting glucose, insulin, and FBF were not significantly different after 7 days of exercise, nor were glucose or insulin responses to the OGTT. However, estimates of whole body insulin sensitivity (Matsuda insulin sensitivity index) increased (P < 0.05). Before exercise training, FBF did not change significantly during the OGTT (1 ± 7, -7 ± 5, 0 ± 6, and 0 ± 5% of fasting FBF at 75, 90, 105, and 120 min, respectively). In contrast, after exercise training, FBF increased by 33 ± 9, 39 ± 14, 34 ± 7, and 48 ± 18% above fasting levels at 75, 90, 105, and 120 min, respectively (P < 0.05 vs. corresponding preexercise time points). Additionally, postprandial glucose responses to a standardized breakfast meal consumed under "free-living" conditions decreased during the final 3 days of exercise (P < 0.05). In conclusion, 7 days of aerobic exercise training improves conduit artery blood flow during an OGTT in individuals with type 2 diabetes.     

Isolation and characterization of two binding proteins for advanced glycosylation end products from bovine lung which are present on the endothelial cell surface.

Nonenzymatic glycosylation of proteins, as occurs at an accelerated rate in diabetes, can lead to the formation of advanced glycosylation end products of proteins (AGEs), which can bind to endothelial cells, thereby altering cellular function in a manner which could contribute to the pathogenesis of diabetic angiopathy. In this report, we describe the isolation of two endothelial cell surface-associated proteins which mediate, at least in part, the interaction of AGEs with endothelium. Based on pilot studies demonstrating AGE binding activity with comparable characteristics in bovine endothelial cell and lung extracts, the material from lung was sequentially subjected to chromatography on hydroxylapatite, fast protein liquid chromatography Mono S, and gel filtration. Two distinct polypeptides, approximately 35 and approximately 80 kDa, were purified to homogeneity, each of which bound AGEs as demonstrated by competitive binding assays using cellular binding proteins immobilized on a plastic surface. NH2-terminal sequence analysis indicated that the approximately 35-kDa protein was novel, whereas the NH2-terminal sequence of the approximately 80-kDa protein was identical to that of lactoferrin. Immunocytologic studies using polyclonal antibody prepared to each of the purified polypeptides demonstrated the presence of immunoreactive material on the surface of bovine endothelial cells maintained under serum-free conditions. Furthermore, immunoelectron microscopic studies with antibodies to the approximately 35- and approximately 80-kDa AGE-binding proteins conjugated to different size colloidal gold particles confirmed the presence of the target antigens on the cell surface and suggested that they were closely associated. IgG purified from polyclonal antisera to either the 35- or 80-kDa AGE-binding proteins blocked the binding of 125I-AGE-albumin to the cell surface. These results indicate that endothelial cells express specific cell surface molecules which mediate AGE-endothelial interaction. These polypeptides represent a novel class of cell surface acceptor molecules for glucose-modified proteins which may promote degradation and/or transcytosis of the ligand, and modulation of cellular function.     

Biofilm formation and antimicrobial sensitivity of lactobacilli contaminants from sugarcane-based fuel ethanol fermentation

Industrial ethanol fermentation is subject to bacterial contamination that causes significant economic losses in ethanol fuel plants. Chronic contamination has been associated with biofilms that are normally more resistant to antimicrobials and cleaning efforts than planktonic cells. In this study, contaminant species of Lactobacillus isolated from biofilms (source of sessile cells) and wine (source of planktonic cells) from industrial and pilot-scale fermentations were compared regarding their ability to form biofilms and their sensitivity to different antimicrobials. Fifty lactobacilli were isolated and the most abundant species were Lactobacillus casei, Lactobacillus fermentum and Lactobacillus plantarum. The majority of the isolates (87.8%) were able to produce biofilms in pure culture. The capability to form biofilms and sensitivity to virginiamycin, monensin and beta-acids from hops, showed inter- and intra-specific variability. In the pilot-scale fermentation, Lactobacillus brevis, L. casei and the majority of L. plantarum isolates were less sensitive to beta-acids than their counterparts from wine; L. brevis isolates from biofilms were also less sensitive to monensin when compared to the wine isolates. Biofilm formation and sensitivity to beta-acids showed a positive and negative correlation for L. casei and L. plantarum, respectively.     

Variation among vocalizations of Taraba major (Aves: Thamnophilidae) subspecies

Geographical variation of bird vocalizations may be related to factors influencing sound production and sound propagation. If birds, e.g. the Great Antshrike (Taraba major), produce vocalizations that develop normally in the absence of learning, these variations may reflect evolutionary divergence within species. In this case, vocal variation could be influenced by habitat structure, since abiotic features and vegetal cover affect sound propagation through environment. Selective pressures may be acting on populations in different ways, which could culminate in a process of speciation. Thus, we searched for structural variation of Great Antshrike vocalizations between subspecies and sought for relationships between these vocal variation and environmental structure. We found variations in frequency and time features of vocalizations among subspecies, which are correlated to latitude, elevation and climate. We also observed an increase in vocal differences along with an increase in distances between individuals, which could reflect isolation of subspecies and the vocal adaptation to different environments.     

<Emphasis Type="Italic">Anemia tomentosa</Emphasis> var. <Emphasis Type="Italic">anthriscifolia</Emphasis> in vitro culture: sporophyte development and volatile compound profile of an aromatic fern

Anemia tomentosa var. anthriscifolia is an aromatic fern with a pleasant woody aroma and antimycobacterial activity. In this paper, we describe for the first time its spore-derived gametophyte development and the effect of indole-3-acetic acid and jasmonic acid on in vitro gametophyte/sporophyte development, as well as volatile compound production. Volatiles were obtained by simultaneous distillation and extraction (SDE) and analyzed by high resolution gas chromatography coupled with mass spectrometry. Spore-derived gametophytes were able to develop into sporophytes independently of the media culture composition, even when no plant growth regulator was added. Fifty different substances were detected in all in vitro A. tomentosa SDE extracts, while 20 were detected in the wild SDE plant extract. Monoterpenes were more prevalent (69.8–89.8%) than sesquiterpenes (9.4–28.7%) in in vitro plants, while sesquiterpenes represent 97.5% of the volatiles produced by the wild-grown plants. The major monoterpene components in in vitro plants were α-pinene (9.3–24.3%), trans-pinocarveol (20.6–27.9%), pinocarvone (15.4–25.1%) and myrtenyl acetate (6.4–12.3%). The triquinane sesquiterpenes silphiperfol-6-ene (0.6–2.9%), α-guaiene (0.5–2.5%), β-barbatene (1.1–3.9%) and 9-epi-presilphiperfolan-1-ol (2.5–5.6%) represent the most abundant sesquiterpenes. The changes in the monoterpene/sesquiterpene rates between micropropagated and wild plants are not related to the presence of JA or IAA in the media culture. Further studies are still needed to obtain a complete understanding of the factors leading to these results, which could be related to differences in the irradiance levels of in vitro plants versus those from a wild environment, as well as the developmental stage of the plants. This is the first report of the use of plant growth regulators on Anemia tomentosa in vitro culture development and their effects on volatile profiles.     

Contrasting patterns of selection between MHC I and II across populations of Humboldt and Magellanic penguins

The evolutionary and adaptive potential of populations or species facing an emerging infectious disease depends on their genetic diversity in genes, such as the major histocompatibility complex (MHC). In birds, MHC class I deals predominantly with intracellular infections (e.g., viruses) and MHC class II with extracellular infections (e.g., bacteria). Therefore, patterns of MHC I and II diversity may differ between species and across populations of species depending on the relative effect of local and global environmental selective pressures, genetic drift, and gene flow. We hypothesize that high gene flow among populations of Humboldt and Magellanic penguins limits local adaptation in MHC I and MHC II, and signatures of selection differ between markers, locations, and species. We evaluated the MHC I and II diversity using 454 next‐generation sequencing of 100 Humboldt and 75 Magellanic penguins from seven different breeding colonies. Higher genetic diversity was observed in MHC I than MHC II for both species, explained by more than one MHC I loci identified. Large population sizes, high gene flow, and/or similar selection pressures maintain diversity but limit local adaptation in MHC I. A pattern of isolation by distance was observed for MHC II for Humboldt penguin suggesting local adaptation, mainly on the northernmost studied locality. Furthermore, trans‐species alleles were found due to a recent speciation for the genus or convergent evolution. High MHC I and MHC II gene diversity described is extremely advantageous for the long‐term survival of the species.     

Age‐related effects of DHEA on peripheral markers of oxidative stress

Ageing is an inevitable biological process characterized by a general decline in various physiological functions. DHEA and DHEAS levels are maximal between the second and third life decades, then start to decline 2% per year, leaving a residual of 10–20% of the peak production by the eighth decade. Erythrocytes are exposed to frequent oxidative stress due to the oxygen radicals continuously generated by haemoglobin auto‐oxidation. We investigated DHEA chronic (10 mg/kg, subcutaneously, for 5 weeks) effects over oxidative stress markers in erythrocytes of male Wistar rats of 3, 13 and 18 month‐old. In the 13 month‐old group, we found increased lipid peroxidation (LPO), superoxide dismutase (SOD), glutathione‐S‐transferase and catalase activities when compared to the other age groups. DHEA produced a marked increase in LPO of 13 month‐old group when compared to its control. DHEA exerted this pro‐oxidant effects in all ages studied, especially in age 13 month‐old. It seems that at 13 month‐old there would be an important depletion of some specific anti‐oxidant in order to determine such susceptibility to DHEA effects. Since this approach allows a minimally invasive assessment, it would be useful as a routine method in human clinical studies investigating DHEA effects during the ageing process. Copyright © 2009 John Wiley & Sons, Ltd.     

Mitotic activity and nuclear/cytoplasmatic ratio of the lachrymal and Harderian glands of the rat during postnatal life.

The authors performed a study of the mitotic activity and the nuclear/cytoplasmic (N/C) ratio during postnatal life of the lachrymal and Harderian glands of the rat. Based on the results, they concluded: (1) during the first days of postnatal life the development of lachrymal and Harderian glands was characterized by an intense mitotic activity and a low N/C ratio; (2) the period prior to eyelid disjunction was characterized by a diminished mitotic activity and a progressive and slow increase of the N/C ratio; (3) after eyelid disjunction, mitotic activity was reduced and an abrupt increase of the N/C ratio occurred, more evident in the Harderian gland; (4) during the final period of postnatal life studied mitotic activity was absent and the N/C ratio presented a higher, more constant level, which was always higher for the Harderian gland.