Chemical characterization (GC/MS and NMR Fingerprinting) and bioactivities of South-African Pelargonium capitatum (L.) L' Her. (Geraniaceae) essential oil

Chemical fingerprinting of commercial Pelargonium capitatum (Geraniaceae) essential oil samples of south African origin was performed by GC, GC/MS, and (13) C- and (1) H-NMR. Thirty-seven compounds were identified, among which citronellol (32.71%) and geraniol (19.58%) were the most abundant. NMR Spectra of characteristic chemicals were provided. Broad-spectrum bioactivity properties of the oil were evaluated and compared with those of commercial Thymus vulgaris essential oil with the aim to obtain a functional profile in terms of efficacy and safety. P. capitatum essential oil provides a good performance as antimicrobial, with particular efficacy against Candida albicans strains. Antifungal activity performed against dermatophyte and phytopathogen strains revealed the latter as more sensitive, while antibacterial activity was not remarkable against both Gram-positive and Gram-negative bacteria. P. capitatum oil provided a lower antioxidant activity (IC(50) ) than that expressed by thyme essential oil, both in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and β-carotene bleaching tests. Results in photochemiluminescence (PCL) assay were negligible. To test the safety aspects of P. capitatum essential oil, mutagenic and toxicity properties were assayed by Ames test, with and without metabolic activation. Possible efficacy of P. capitatum essential oil as mutagenic protective agent against NaN(3) , 2-nitrofluorene, and 2-aminoanthracene was also assayed, providing interesting and significant antigenotoxic properties.     

PRKX critically regulates endothelial cell proliferation, migration, and vascular-like structure formation

Angiogenesis is a fundamental step in several important physiological events and pathological conditions including embryonic development, wound repair, tumor growth and metastasis. PRKX was identified as a novel type-I cAMP-dependent protein kinase gene expressed in multiple developing tissues. PRKX has also been shown to be phylogenetically and functionally distinct from PKA. This study presents the first evidence that PRKX stimulates endothelial cell proliferation, migration, and vascular-like structure formation, which are the three essential processes for angiogenesis. In contrast, classic PKA demonstrated an inhibitory effect on endothelia vascular-like structure formation. Our findings suggest that PRKX is an important protein kinase engaged in the regulation of angiogenesis and could play critical roles in various physiological and pathological conditions involving angiogenesis. PRKX binds to Pin-1, Magi-1 and Bag-3, which regulate cell proliferation, apoptosis, differentiation and tumorigenesis. The interaction of PRKX with Pin-1, Magi-1 and Bag-3 could contribute to the stimulating role of PRKX in angiogenesis.     

Insect cells and their potential as stabilization barriers for DNA of multiple and single nucleopolyhedroviruses against ultraviolet-B-simulated sunlight inactivation

A cell line from Trichoplusia ni (TN-CL1) infected with the Autographa californica multiple nucleopolyhedrovirus (AcMNPV-HPP) and a cell line from Helicoverpa zea (BCIRL-HZ-AM1) infected with the Helicoverpa zea single nucleopolyhedrovirus (HzSNPV/BrCL2) were subjected to ultraviolet-B (UV-B) irradiation at a predetermined level of exposure that would inactivate greater than 95% of the virus suspended in the liquid. The working hypothesis was that the homologous insect cells would utilize their inherent deoxyribonucleic acid (DNA) repair mechanism(s) to prevent, repair, or at least mitigate the damaging effects of UV-B light on viral DNA synthesis. We attempted to determine this by using infected cells that were subjected to UV-B irradiation at different postinoculation periods under two experimental conditions of exposure: (1) shielded, and (2) nonshielded. Of the two cell lines infected with their respective homologous viruses, the virus from TN-CL1 cells was the least sensitive to UV-B light because the extracellular virus (ECV) and occlusion body (OB) levels of virus-infected TN-CL1 cells were higher than those of the virus-infected BCIRL-HZ-AM1 cells. Production of ECV and OB from both cell lines was lower in the exposed, nonshielded treatment than in the exposed, shielded treatment. However, AcMNPV-HPP was produced in enough quantity to indicate that TN-CL1 might impart a level of protection to the virus against UV light.     

Increased isolation of two Biosphere Reserves and surrounding protected areas (WAP ecological complex, West Africa)

Protected areas such as nature reserves have been found to be effective in preventing habitat destruction and protecting ecosystems within their borders. Recent studies however found extensive loss of tropical forest habitat around protected areas, vastly contributing to increase the levels of ecological isolation. Using high-resolution satellite data we investigated the isolation trend occurring in the W-Arly-Pendjari (WAP) ecological complex in West Africa. A land-cover change analysis was performed for the period 1984–2002: savanna vegetation extension and loss were derived within the complex and in a 30 km peripheral buffer. Sample regions in the buffer were also analysed using selected spatial indicators to quantify temporal trends in habitat fragmentation. Implications for change in relative capacity to conserve biodiversity were discussed through the calculation of the species richness capacity (SRC). More than 14.5% of savanna habitat was lost in the WAP peripheral areas, while 0.3% was converted inside the complex. The degree of fragmentation of remnant savanna habitat has also drastically increased. Despite the effectiveness of the park conservation programme, we found through the SRC approach that the WAP complex is decreasing its potential capacity to conserve species richness. This process is mainly due to the rapid and extended agricultural expansion taking place around the complex. A better understanding of the ecological dynamics occurring in the peripheral regions of reserves and the consideration of development needs are key variables to achieve conservation goals in protected areas.     

Genome Size: A Novel Genomic Signature in Support of Afrotheria

Molecular phylogenetic analyses suggest an emerging phylogeny for the extant Placentalia (eutherian) that radically departs from morphologically based constructions of the past. Placental mammals are partitioned into four supraordinal clades: Afrotheria, Xenarthra, Laurasiatheria, and Euarchontoglires. Afrotheria form an endemic African clade that includes elephant shrews, golden moles, tenrecs, aardvarks, hyraxes, elephants, dugongs, and manatees. Datamining databases of genome size (GS) shows that till today just one afrotherian GS has been evaluated, that of the aardvark Orycteropus afer. We show that the GSs of six selected representatives across the Afrotheria supraordinal group are among the highest for the extant Placentalia, providing a novel genomic signature of this enigmatic group. The mean GS value of Afrotheria, 5.3 ± 0.7 pg, is the highest reported for the extant Placentalia. This should assist in planning new genome sequencing initiatives. [Reviewing Editor: Dmitri Petrov]     

Identification of new antigenic peptide presented by HLA-Cw7 and encoded by several MAGE genes using dendritic cells transduced with lentiviruses

Antigens encoded by MAGE genes are of particular interest for cancer immunotherapy because they are tumor specific and shared by tumors of different histological types. Several clinical trials are in progress with MAGE peptides, proteins, recombinant poxviruses, and dendritic cells (DC) pulsed with peptides or proteins. The use of gene-modified DC would offer the major advantage of a long-lasting expression of the transgene and a large array of antigenic peptides that fit into the different HLA molecules of the patient. In this study, we tested the ability of gene-modified DC to prime rare Ag-specific T cells, and we identified a new antigenic peptide of clinical interest. CD8(+) T lymphocytes from an individual without cancer were stimulated with monocyte-derived DC, which were infected with a second-generation lentiviral vector encoding MAGE-3. A CTL clone was isolated that recognized peptide EGDCAPEEK presented by HLA-Cw7 molecules, which are expressed by >40% of Caucasians. Interestingly, this new tumor-specific antigenic peptide corresponds to position 212-220 of MAGE-2, -3, -6, and -12. HLA-Cw7 tumor cell lines expressing one of these MAGE genes were lysed by the CTL, indicating that the peptide is efficiently processed in tumor cells and can therefore be used as target for antitumoral vaccination. The risk of tumor escape due to appearance of Ag-loss variants should be reduced by the fact that the peptide is encoded by several MAGE genes.     

Firing rates of motor units in human vastus lateralis muscle during fatiguing isometric contractions.

We investigated the firing rate of motor units in the vastus lateralis muscle in five healthy young men (mean = 21.4 yr, SD = 0.9) during a sequence of isometric constant-torque contractions repeated to exhaustion. The contractions were sustained at 20% of the maximal voluntary level, measured at the beginning of the test sequence. Electromyographic (EMG) signals were recorded via quadrifilar fine-wire electrodes and subsequently decomposed into their constituent motor unit action potentials to obtain the motor unit firing times. In addition, we measured the whole muscle mechanical properties during the fatigue task using electrical stimulation. The firing rate of motor units first decreased within the first 10-20% of the endurance time of the contractions and then increased. The firing rate increase was accompanied by recruitment of additional motor units as the force output remained constant. The elicited twitch and tetanic torque responses first increased and then decreased. The two processes modulated in a complementary fashion at the same time. Our data suggest that, when the vastus lateralis muscle is activated to maintain a constant torque output, its motoneuron pool receives a net excitatory drive that first decreases to compensate for the short-lived potentiation of the muscle force twitch and then increases to compensate for the diminution of the force twitch. The underlying inverse relationship between the firing rate and the recruitment threshold that has been reported for nonfatigued contractions is maintained. We, therefore, conclude that the central nervous system control of vastus lateralis motor units remains invariant during fatigue in submaximal isometric isotonic contractions.     

Host Determinants of Helicobacter pylori Infection and Its Clinical Outcome

Greater than one-half of the world's population harbors Helicobacter pylori. The majority of infected individuals, however, remain asymptomatic, with only 10% to 20% developing diseases, including peptic ulcer disease, gastric cancer, and gastric mucosa–associated lymphoid tissue lymphoma. This article reviews host factors that may predispose an individual to both the acquisition of H. pylori infection and subsequent clinical outcome. Individuals with specific blood group antigens and human leukocyte antigen genotypes may be more susceptible to H. pylori infection. Additional factors, such as the age of acquisition, the host immune response, the site of infection, acid secretion, and interactions with nonhost factors (including bacterial virulence factors and environmental influences) may play a role in determining clinical outcome. Further investigation is required to clarify the mechanisms by which these interactions occur and, more critically, to determine their relative importance. This knowledge will enable the identification of individuals at risk of developing clinical disease with H. pylori infection.