Nitric Oxide Functions as a Positive Regulator of Root Hair Development

The root epidermis is composed of two cell types: trichoblasts (or hair cells) and atrichoblasts (or non-hair cells). In lettuce (Lactuca sativa cv. Grand Rapids var. Rapidmor oscura) plants grown hydroponically in water, the root epidermis did not form root hairs. The addition of 10 µM sodium nitroprusside (SNP), a nitric oxide (NO) donor, resulted in almost all rhizodermal cells differentiated into root hairs. Treatment with the synthetic auxin 1-naphthyl acetic acid (NAA) displayed a significant increase of root hair formation (RHF) that was prevented by the specific NO scavenger carboxy-PTIO (cPTIO). In Arabidopsis, two mutants have been shown to be defective in NO production and to display altered phenotypes in which NO is implicated. Arabidopsis nos1 has a mutation in an NO synthase structural gene (NOS1), and the nia1 nia2 double mutant is null for nitrate reductase (NR) activity. We observed that both mutants were affected in their capacity of developing root hairs. Root hair elongation was significantly reduced in nos1 and nia1 nia2 mutants as well as in cPTIO-treated wild type plants. A correlation was found between endogenous NO level in roots detected by the fluorescent probe DAF-FM DA and RHF. In Arabidopsis, as well as in lettuce, cPTIO blocked the NAA-induced root hair elongation. Taken together, these results indicate that: (1) NO is a critical molecule in the process leading to RHF and (2) NO is involved in the auxin-signaling cascade leading to RHF.Key Words: auxin, nitric oxide, root hair, lettuce, arabidopsis, nos1 mutant, nia1, nia2 mutant     

Antisettlement activity of synthetic analogues of polymeric 3-alkylpyridinium salts isolated from the sponge Reniera sarai

Based on the high, non-toxic and reversible antifouling activity of the polymeric 3-alkylpyridinium salts isolated from the sponge Reniera sarai, the anti-settlement activity and toxicity of a series of synthetic analogues has been studied. All the test compounds were less efficient than the natural polymers, suggesting that the high and reversible anti-macrofouling activity of the natural polymers could derive from their detergent-like properties. The values obtained for EC50sett. of inhibition of cyprid settlement and EC50imm. as naupliar toxicity for the synthetic compounds indicate that the presence of single or multiple charges in the structure is not relevant for the antifouling activity which, conversely, is favoured by increasing the length of the alkyl chain, or by the presence of uncharged pyridine units. The compound 1,8-di(3-pyridyl)octane was the most efficient (EC50sett. = 0.44 microgml(-1)), although with a higher toxicity on naupliar stage of B. amphitrite than the natural polymers.     

PERMANENT GENETIC RESOURCES: Isolation and characterization of microsatellite loci from the Arctic cisco (Coregonus autumnalis)

Eight polymorphic microsatellite loci were isolated and characterized for the Arctic cisco, Coregonus autumnalis. Loci were evaluated in 21 samples from the Colville River subsistence fishery. The number of alleles per locus ranged from two to 18. Observed heterozygosity of loci varied from 0.10 to 1.00, and expected heterozygosity ranged from 0.09 to 0.92. All eight microsatellite markers were in Hardy-Weinberg equilibrium. The loci presented here will be useful in describing population structure and exploring populations of origin for Arctic cisco.     

Contribution to the environmental ecology of Cryptogramma crispa (L.) R. Br. ex Hooker in the Alps

We studied the habitat characteristics in a number of Cryptogramma crispa stations throughout the Alps. Our objectives were: (1) to define the environmental ecology of C. crispa in the southern part of its distributional area in Europe; (2) to test the reliability of ecological indicator values of soil reaction, nutrient and dispersion status, light and temperature for this species. The habitats of C. crispa mostly consisted in coarse-grained stable screes (on rock slide deposits, talus cones, talus sheets, stone fields and moraines), within a broad elevation range with maximum frequency in the subalpine and lower alpine vegetation belts. At higher altitudes, C. crispa was mostly found on South-exposed slopes with high potential irradiance, whereas at low altitude it was most abundant on North-exposed rather gentle slopes formed of big boulders. The screes colonized by C. crispa were formed of acid metamorphic rocks or igneous rocks and had a coarse texture. The soil accumulated in the spaces among boulders had sandy texture and acidic reaction, with medium to high carbon and total nitrogen contents. Calcium lacks entirely in the soil. Our field data gave support to the Ellenberg–Landolt ecological indicator values of light and temperature, but not to those of soil reaction and soil nutrient content, for which some changes are proposed.     

Enhancing the immunogenicity of a permissive binding T cell epitope derived from the simian immunodeficiency virus-encoded negative regulatory factor.

Using the murine system we have analyzed an immunogenic T cell peptide epitope corresponding to amino acids 96-112 of the simian immunodeficiency virus-negative regulatory protein sequence. This epitope was unusual in that it was strongly immunogenic in mice of five of the six H-2 haplotypes tested. We generated a T cell hybridoma (SVNF) specific for this peptide in order to determine how manipulating the peptide might alter its immunogenicity. Substitution analysis showed that His 103, Pro 104, Val 106, and Pro 107 were important amino acids for stimulating SVNF because substitutions at these positions diminished the reactivity of SVNF. However, we also found that substituting an Ala for a Val at position 100 or a Val for an Ala at position 110 enhanced reactivity of SVNF. We were able to further enhance the immunogenicity of this epitope by extending the carboxyl terminus two amino acids and making the resulting carboxyl-terminal Lys an amide and by adding a Glu to the amino terminus. These modifications shifted the in vitro activity of SVNF at least two orders of magnitude. We also compared the ability of this modified peptide and the wild-type SIV nef 96-112 to prime a T cell response in vivo. We primed mice with various doses of either the wild-type or the modified peptide and looked at the ability of the draining lymph node cells to proliferate to wild-type peptide. We found that the modified peptide was 10- to 100-fold better at priming a T cell response than the wild-type peptide. Therefore, we were able to create a peptide that was more immunogenic than the wild-type peptide in vivo as well as in vitro. Manipulations such as these that enhance the immunogenicity of T cell epitopes must be considered in developing peptide vaccines against HIV or other infectious agents.     

Selection and validation of a set of reliable reference genes for quantitative RT-PCR studies in the brain of the Cephalopod Mollusc Octopus vulgaris

Background  

Quantitative real-time polymerase chain reaction (RT-qPCR) is valuable for studying the molecular events underlying physiological and behavioral phenomena. Normalization of real-time PCR data is critical for a reliable mRNA quantification. Here we identify reference genes to be utilized in RT-qPCR experiments to normalize and monitor the expression of target genes in the brain of the cephalopod mollusc Octopus vulgaris, an invertebrate. Such an approach is novel for this taxon and of advantage in future experiments given the complexity of the behavioral repertoire of this species when compared with its relatively simple neural organization.     

Effects of a vitamin D3 analog on diabetes in the bio breeding (BB) rat

Non-hypercalcemic analogs of vitamin D(3) modulate the immune response through antigen-presenting cells (APCs) and activated T-cells. A large population-base case-control showed that vitamin D(3) intake significantly decreases the risk of type 1 diabetes development. The aim of this study was, therefore, to observe the in vivo effects of a vitamin D(3) analog administered to Bio Breeding (BB) rats. 1,25-Dihydroxy-16,23Z-diene-26,27-hexafluoro-19-nor vitamin D(3) (BXL-219, formerly Ro 26-2198) (BioXell, Milan, Italy) was administered in vivo to BB rats from days 42 to 110 of life at 0.2 microg/Kg BW. Control animals received only vehicle (olive oil, 4.8 microl/100 g BW). The animals of these two groups were subjected to insulin treatment as they became diabetic. Insulin (Humulin, 28.6 UI/day) was administered irrespective of diabetes occurrence to another group of rats for comparison. Blood glucose, insulin levels, glycosuria, degree of islet infiltration, and the expression of some antigens were observed. Results showed that the vitamin D(3) analog reduced diabetes incidence, although limitedly, in BB rats while administration of oral insulin increased diabetes incidence. In addition, the vitamin D(3) analog did not stimulate an enhancement in the expression of CD4 and CD25 in BB rats as it does in NOD mice, which may explain the failure of this as well as other antidiabetic treatments in the BB animal model of type 1 diabetes.     

Hydroxytyrosol from olive fruits prevents blue-light-induced damage in human keratinocytes and fibroblasts

Skin aging is a complex biological process influenced by a combination of endogenous or intrinsic and exogenous or extrinsic factors due to environmental damage. The primary environmental factor that causes human skin aging is the ultraviolet irradiation from the sun. Recently, it was established that the long-term exposure to light-emitting-diode-generated blue light (LED-BL) from electronic devices seems to have a relevant implication in the molecular mechanisms of premature photoaging. BL irradiation induces changes in the synthesis of various skin structures through DNA damage and overproduction of reactive oxygen species (ROS), matrix metalloproteinase-1 and -12, which are responsible for the loss of the main components of the extracellular matrix of skin like collagen type I and elastin. In the current study, using human keratinocytes and fibroblasts exposed to specific LED-BL radiation doses (45 and 15 J/cm ²), we produced an in vitro model of skin photoaging. We verified that, compared with untreated controls, the treatment with LED-BL irradiation results in the alteration of metalloprotease-1 (collagenase), metalloprotease-12 (elastase), 8-dihydroxy-2′-deoxyguanosine, proliferating cell nuclear antigen, and collagen type I. Moreover, we showed that the photoaging prevention is possible via the use of hydroxytyrosol extracted from olive fruits, well known for antioxidant properties. Our results demonstrated that hydroxytyrosol protects keratinocytes and fibroblasts from LED-BL-induced damage. Thus, hydroxytyrosol might be proposed as an encouraging candidate for the prevention of BL-induced premature photoaging.