Effect of climatic variation on the relative abundance of the red alga Gelidium robustum in Baja California Sur, Mexico

The red alga Gelidium robustum is important,because of its commercial exploitation in Mexico as araw material for the agar industry, providing 10% ofthe world production of agarophytes. In recent years,its annual harvest in Mexico has shownobvious,variations partly because of an increasedharvesting effort, but also because of environmentalchanges. An analysis is presented of the effect thatinterannual variability of the sea surfacetemperature, wind speed, and upwelling index had onthe relative abundance of this alga from 1980 to 1990.The results indicate a close relation betweenenvironmental fluctuations and the relative abundanceof this species. The response of G. robustum tothe different environmental conditions has not alwaysbeen equal. During El Niño 1982–84, the seasurface temperature was the most important factor andthere was a high negative correlation with therelative abundance. A lag period of three monthsshowed a positive correlation with upwelling index andwind speed. Under normal conditions and during LaNiña, the relative abundance of the alga showed apositive correlation with the sea surface temperature. For the upwelling index and wind speed, therelationship was similar to that during El Niño.     

Overexpression of <Emphasis Type="Italic">AtGRDP2</Emphasis> gene in common bean hairy roots generates vigorous plants with enhanced salt tolerance

Proteins with glycine-rich repeats have been identified in plants, mammalians, fungi, and bacteria. Plant glycine-rich proteins have been associated to stress response. Previously, we reported that the Arabidopsis thaliana AtGRDP2 gene, which encodes a protein with a glycine-rich domain, plays a role in growth and development of A. thaliana and Lactuca sativa. In this study, we generated composite Phaseolus vulgaris plants that overexpress the AtGRDP2 gene in hairy roots generated by Agrobacterium rhizogenes. We observed that hairy roots harboring the AtGRDP2 gene developed more abundant and faster-growing roots than control hairy roots generated with the wild type A. rhizogenes. In addition, composite common bean plants overexpressing the AtGRDP2 gene in roots were more tolerant to salt stress showing increments in their fresh and dry weight. Our data further support the role of plant GRDP genes in development and stress response.     

Improvement of the transfucosylation activity of α-l-fucosidase from Thermotoga maritima for the synthesis of fucosylated oligosaccharides in the presence of calcium and sodium

The influence of CaCl₂ and NaCl in the hydrolytic activity and the influence of CaCl₂ in the synthesis of fucosylated oligosaccharides using α-l-fucosidase from Thermotoga maritima were evaluated. The hydrolytic activity of α-l-fucosidase from Thermotoga maritima displayed a maximum increase of 67% in the presence of 0.8 M NaCl with water activity (a_w) of 0.9672 and of 138% in the presence of 1.1 M CaCl₂ (a_w 0.9581). In addition, the hydrolytic activity was higher when using CaCl₂ compared to NaCl at a_w of 0.8956, 0.9581 and 0.9672. On the other hand, the effect of CaCl₂ in the synthesis of fucosylated oligosaccharides using 4-nitrophenyl-fucose as donor substrate and lactose as acceptor was studied. In these reactions, the presence of 1.1 M CaCl₂ favored the rate of transfucosylation, and improved the yield of synthesis duplicating and triplicating it with lactose concentrations of 58 and 146 mM, respectively. CaCl₂ did not significatively affect hydrolysis rate in these reactions. The combination of the activating effect of CaCl₂, the decrement in a_w and lactose concentration had a synergistic effect favoring the synthesis of fucosylated oligosaccharides.

     

Reduction of hepatitis C virus NS5A hyperphosphorylation by selective inhibition of cellular kinases activates viral RNA replication in cell culture

Efficient replication of hepatitis C virus (HCV) subgenomic RNA in cell culture requires the introduction of adaptive mutations. In this report we describe a system which enables efficient replication of the Con1 subgenomic replicon in Huh7 cells without the introduction of adaptive mutations. The starting hypothesis was that high amounts of the NS5A hyperphosphorylated form, p58, inhibit replication and that reduction of p58 by inhibition of specific kinase(s) below a certain threshold enables HCV replication. Upon screening of a panel of kinase inhibitors, we selected three compounds which inhibited NS5A phosphorylation in vitro and the formation of NS5A p58 in cell culture. Cells, transfected with the HCV Con1 wild-type sequence, support HCV RNA replication upon addition of any of the three compounds. The effect of the kinase inhibitors was found to be synergistic with coadaptive mutations in NS3. This is the first direct demonstration that the presence of high amounts of NS5A-p58 causes inhibition of HCV RNA replication in cell culture and that this inhibition can be relieved by kinase inhibitors.     

Isolation and genetic characterization of a relapsing fever spirochete isolated from Ornithodoros puertoricensis collected in central Panama

Tick-borne relapsing fever (TBRF) spirochetes are likely an overlooked cause of disease in Latin America. In Panama, the pathogens were first reported to cause human disease in the early 1900s. Recent collections of Ornithodoros puertoricensis from human dwellings in Panama prompted our interest to determine whether spirochetes still circulate in the country. Ornithodoros puertoricensis ticks were collected at field sites around the City of Panama. In the laboratory, the ticks were determined to be infected with TBRF spirochetes by transmission to mice, and we report the laboratory isolation and genetic characterization of a species of TBRF spirochete from Panama. Since this was the first isolation of a species of TBRF spirochete from Central America, we propose to designate the bacteria as Borrelia puertoricensis sp. nov. This is consistent with TBRF spirochete species nomenclature from North America that are designated after their tick vector. These findings warrant further investigations to assess the threat B. puertoricensis sp. nov. may impose on human health.     

Isolation and identification of mycobacteria from livestock specimens and milk obtained in Brazil

The prevalence of Mycobacterium bovis and other mycobacterial species in livestock specimens and milk was evaluated. An emphasis was placed upon the distribution of these organisms in milk that is readily available to the public that was either untreated, pasteurized, or treated using ultra high temperature. Twenty-two pathologic specimens from livestock (bovine, swine and bubaline) in five Brazilian states and 128 bovine milk samples from retail markets in the State of S o Paulo were examined for mycobacteria. Identification was made by classical biochemical tests, thin layer chromatography of mycolic acids and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Mycobacteria were isolated from 15 (68.2%) caseous lesions and from 23 (18%) milk samples. Eleven isolates were identified as M. bovis, and the remaining 27 nontuberculous mycobacterial isolates were represented by five species and six unidentified rapidly growing mycobacterial strains. The data demonstrate that animal products in Brazil are frequent reservoirs of mycobacteria and may pose a risk to the public.     

Do lianas shape ant communities in an early successional tropical forest?

Almost half of lowland tropical forests are at various stages of regeneration following deforestation or fragmentation. Changes in tree communities along successional gradients have predictable bottom‐up effects on consumers. Liana (woody vine) assemblages also change with succession, but their effects on animal succession remain unexplored. Here we used a large‐scale liana removal experiment across a forest successional chronosequence (7–31 years) to determine the importance of lianas to ant community structure. We conducted 1,088 surveys of ants foraging on and living in trees using tree trunk baiting and hand‐collecting techniques at 34 paired forest plots, half of which had all lianas removed. Ant species composition, β‐diversity, and species richness were not affected by liana removal; however, ant species co‐occurrence (the coexistence of two or more species in a single tree) was more frequent in control plots, where lianas were present, versus removal plots. Forest stand age had a larger effect on ant community structure than the presence of lianas. Mean ant species richness in a forest plot increased by ca. 10% with increasing forest age across the 31‐year chronosequence. Ant surveys from forest >20 years old included more canopy specialists and fewer ground‐nesting ant species versus those from forests <20 years old. Consequently, lianas had a minimal effect on arboreal ant communities in this early successional forest, where rapidly changing tree community structure was more important to ant species richness and composition.     

Two new remarkable Nolinaceae from Central Mexico

Two new species of Nolinaceae are described and illustrated. The first is a ponytail palm,Beaucarnea compacta, occuring in xerophytic scrub in the Sierra Madre Oriental near Atarjea, Guanajuato. The second new species isCalibanus glassianus, adding the second species to the genusCalibanus. This new species is found in the transition between tropical deciduous forest to subontane scrub in the Sierra Madre Oriental near Xichú, Guanajuato.

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Se describen e ilustran dos nuevas especies de Nolinaceae. La primera es una pata de elefante o palma petacona,Beaucarnea compacta. Se distribuye en matorrales xerófitos de la Sierra madre Oriental cerca de Atarjea, Guanajuato. La segunda nueva especie esCalibanus glassianus, que adiciona una especie más al géneroCalibanus. Esta nueva especie se encuentra en la transición de bosques tropicales caducifolios con matorrales xerófilos de la sierra Madre Oriental en los alrededores de Xichú, Guanajuato.

     

Production of a Plant-Derived Immunogenic Protein Targeting ApoB100 and CETP: Toward a Plant-Based Atherosclerosis Vaccine

In an effort to initiate the development of a plant-based vaccination model against atherosclerosis, a cholera toxin B subunit (CTB)-based chimeric protein was designed to target both ApoB100 and CETP epitopes associated with immunotherapeutic effects in atherosclerosis. Epitopes were fused at the C-terminus of CTB to yield a protein called CTB:p210:CETPe. A synthetic gene coding for CTB:p210:CETPe was successfully transferred to tobacco plants with no phenotypic alterations. Plant-derived CTB:p210:CETPe was expressed and assembled in the pentameric form. This protein retained the target antigenic determinants, as revealed by GM1-ELISA and Western blot analyses. Higher expresser lines reached recombinant protein accumulation levels up to 10 µg/g fresh weight in leaf tissues and these lines carry a single insertion of the transgene as determined by qPCR. Moreover, when subcutaneously administered, the biomass from these CTB:p210:CETPe-producing plants was able to elicit humoral responses in mice against both ApoB100 and CETP epitopes and human serum proteins. These findings evidenced for the first time that atherosclerosis-related epitopes can be expressed in plants retaining immunogenicity, which opens a new path in the molecular farming field for the development of vaccines against atherosclerosis.