Common bacterial responses in six ecosystems exposed to 10 years of elevated atmospheric carbon dioxide

Six terrestrial ecosystems in the USA were exposed to elevated atmospheric CO(2) in single or multifactorial experiments for more than a decade to assess potential impacts. We retrospectively assessed soil bacterial community responses in all six-field experiments and found ecosystem-specific and common patterns of soil bacterial community response to elevated CO(2) . Soil bacterial composition differed greatly across the six ecosystems. No common effect of elevated atmospheric CO(2) on bacterial biomass, richness and community composition across all of the ecosystems was identified, although significant responses were detected in individual ecosystems. The most striking common trend across the sites was a decrease of up to 3.5-fold in the relative abundance of Acidobacteria Group 1 bacteria in soils exposed to elevated CO(2) or other climate factors. The Acidobacteria Group 1 response observed in exploratory 16S rRNA gene clone library surveys was validated in one ecosystem by 100-fold deeper sequencing and semi-quantitative PCR assays. Collectively, the 16S rRNA gene sequencing approach revealed influences of elevated CO(2) on multiple ecosystems. Although few common trends across the ecosystems were detected in the small surveys, the trends may be harbingers of more substantive changes in less abundant, more sensitive taxa that can only be detected by deeper surveys. Representative bacterial 16S rRNA gene clone sequences were deposited in GenBank with Accession No. JQ366086–JQ387568.     

Lipid content and apoptosis of in vitro-produced bovine embryos as determinants of susceptibility to vitrification

The objective was to evaluate supplementation of fetal calf serum (FCS) and phenazine ethosulfate (PES), a metabolic regulator that inhibits fatty acid synthesis, in culture media during in vitro production (IVP) of bovine embryos. Taking oocyte fertilization (n = 4,320) as Day 0, four concentrations of FCS (0, 2.5, 5, and 10%) and three periods of exposure to PES (without addition—Control; after 60 h—PES Day 2.5 of embryo culture; and after 96 h—PES Day 4) were evaluated. Increasing FCS concentration in the culture media enhanced lipid accumulation (P < 0.05), increased apoptosis in fresh (2.5%: 19.1 ± 1.8 vs 10%: 28.4 ± 2.3, P < 0.05; mean ± SEM) and vitrified (2.5%: 42.8 ± 2.7 vs 10%: 69.2 ± 3.4, P < 0.05) blastocysts, and reduced blastocoele re-expansion after vitrification (2.5%: 81.6 ± 2.5 vs 10%: 67.3 ± 3.5, P < 0.05). The addition of PES in culture media, either from Days 2.5 or 4, reduced lipid accumulation (P < 0.05) and increased blastocoele re-expansion after vitrification (Control: 72.0 ± 3.0 vs PES Day 2.5: 79.9 ± 2.8 or PES Day 4: 86.2 ± 2.4, P < 0.05). However, just the use of PES from D4 reduced apoptosis in vitrified blastocysts (Control: 52.0 ± 3.0 vs PES Day 4: 39.2 ± 2.4, P < 0.05). Independent of FCS withdrawal or PES addition to culture media, the in vivo control group had lesser lipid accumulation, a lower apoptosis rate, and greater cryotolerance (P < 0.05). The increased lipid content was moderately correlated with apoptosis in vitrified blastocysts (r = 0.64, P = 0.01). In contrast, the increased apoptosis in fresh blastocysts was strongly correlated with apoptosis in vitrified blastocysts (r = 0.94, P < 0.0001). Therefore, using only 2.5% FCS and the addition of PES from Day 4, increased the survival of IVP embryos after vitrification. Moreover, embryo quality, represented by the fresh apoptosis rate, was better than lipid content for predicting embryo survival after vitrification.     

Reassembly of a large multisubunit protein promoted by nonprotein factors. Effects of calcium and glycerol on the association of extracellular hemoglobin

The effects of cations and glycerol on the dissociation induced by pressure and on the reassembly of Glossoscolex paulistus hemoglobin were examined by light scattering, gel filtration, and electron microscopy. Calcium stabilized the quaternary structure of the hemoglobin against pressure dissociation. In the presence of 50 mM Ca2+, the half-dissociation pressure (p 1/2) increased by 400 bar, which corresponds to an average stabilization of -0.62 kcal/mol of dissociating subunit. Calcium also promoted a large increase in the yield of recovery of fully assembled hemoglobin at the expense of the partially dissociated (one-twelfth subunit) and fully dissociated forms. Glycerol protected the hemoglobin from pressure dissociation, increasing the half-dissociation pressure (p 1/2) and promoted an increase in the yield of recovery of fully assembled hemoglobin by about 40%. Addition of calcium after return to atmospheric pressure increased recovery of the fully associated form only in a long time scale (many days). The existence of time-dependent changes in the conformation of the dissociated subunits is suggested to explain the partial association to one-twelfth subaggregates (drifted forms) that lack the ability to reassemble to native hemoglobin. The promotion of reassembly by nonprotein factors (calcium and glycerol) is suggested to occur by preventing the formation of wrong intermediate forms (drifted one-twelfth subunits).     

Epipelagic siphonophore assemblages associated with water masses along a transect between Chile and Easter Island (eastern South Pacific Ocean)

We analyze for the first time the spatial distribution of siphonophoresin relation to water masses along a 3750-km oceanic transectbetween the Chilean coast and the Easter Island (27° S),a sector scarcely known of eastern South Pacific Ocean. Thirty-onesiphonophore species were identified; Sulculeolaria turgidaand Vogtia glabra were recorded for the first time in this sector.The most abundant species were Muggiaea atlantica (29.2%), Eudoxoidesspiralis (24.5%) and Lensia subtilis (13.1%). Two differentsiphonophore assemblages east and west of 76 W, associated respectivelywith Subantarctic Water and Subtropical Water masses, can beused as water mass indicators. The former included the threemost abundant species, whereas the latter showed greater speciesrichness. This study provides basic knowledge on spatial distributionof siphonophores, which is important to develop future researchfocused on understanding the ecological role and biologicalprocesses driven by planktonic organisms in the southeasternPacific Ocean.     

VGJ phi, a novel filamentous phage of Vibrio cholerae, integrates into the same chromosomal site as CTX phi

We describe a novel filamentous phage, designated VGJ phi, isolated from strain SG25-1 of Vibrio cholerae O139, which infects all O1 (classical and El Tor) and O139 strains tested. The sequence of the 7,542 nucleotides of the phage genome reveals that VGJ phi has a distinctive region of 775 nucleotides and a conserved region with an overall genomic organization similar to that of previously characterized filamentous phages, such as CTX phi of V. cholerae and Ff phages of Escherichia coli. The conserved region carries 10 open reading frames (ORFs) coding for products homologous to previously reported peptides of other filamentous phages, and the distinctive region carries one ORF whose product is not homologous to any known peptide. VGJ phi, like other filamentous phages, uses a type IV pilus to infect V. cholerae; in this case, the pilus is the mannose-sensitive hemagglutinin. VGJ phi-infected V. cholerae overexpresses the product of one ORF of the phage (ORF112), which is similar to single-stranded DNA binding proteins of other filamentous phages. Once inside a cell, VGJ phi is able to integrate its genome into the same chromosomal attB site as CTX phi, entering into a lysogenic state. Additionally, we found an attP structure in VGJ phi, which is also conserved in several lysogenic filamentous phages from different bacterial hosts. Finally, since different filamentous phages seem to integrate into the bacterial dif locus by a general mechanism, we propose a model in which repeated integration events with different phages might have contributed to the evolution of the CTX chromosomal region in V. cholerae El Tor.     

New circuits for old memories: the role of the neocortex in consolidation

Studies of learning and memory have provided a great deal of evidence implicating hippocampal mechanisms in the initial storage of facts and events. However, until recently, there were few hints as to how and where this information was permanently stored. A recent series of rodent molecular and cellular cognition studies provide compelling evidence for the involvement of specific neocortical regions in the storage of information initially processed in the hippocampus. Areas of the prefrontal cortex, including the anterior cingulate and prelimbic cortices, and the temporal cortex show robust increases in activity specifically following remote memory retrieval. Importantly, damage to or inactivation of these areas produces selective remote memory deficits. Additionally, transgenic studies provide glimpses into the molecular and cellular mechanisms underlying cortical memory consolidation. The studies reviewed here represent the first exciting steps toward the understanding of the molecular, cellular, and systems mechanisms of how the brain stores our oldest and perhaps most defining memories.     

The surface free energy of Leishmania mexicana amazonensis.

Surface charge of Leishmania mexicana amazonensis was investigated by direct zeta-potential determination and ultrastructural cytochemistry, and its surface tension was studied by measurements of the advancing contact angle formed by the parasite monolayers with drops of liquids of different polarities. Both virulent and avirulent promastigotes exhibited negatively charged surfaces with a zeta-potential of about -15 mV. Treatment of these cells with trypsin, alkaline phosphatase, or phospholipase C rendered their surfaces less negatively charged, whereas neuraminidase did not alter the parasite negativeness. Cytochemically, we could observe a reduction in the cationized ferritin binding after the parasite treatment with each of the former enzymes, but not with neuraminidase. The surface free energy of parasites was calculated by taken to account the London dispersion, the Keeson dipole-dipole, and the Debye dipole-induced forces, as well as the surface polarity of the parasites and their zeta-potentials, by considering their adhesion to polystyrene surfaces. The delta G values of -6.4 and -18.1 mJ.m-2 were obtained for avirulent and virulent promstigotes, respectively.     

Morphology and Phylogeny of Calyptospora paranaidji n. sp. (Eimeriorina: Calyptosporidae), an Apicomplexan Parasite of the Hepatic Tissue of Cichla piquiti Kullander & Ferreira, 2006, From a Reservoir in the Brazilian Amazon Region

The coccidians of the family Calyptosporidae are parasites of the tissue and organs of fish and aquatic invertebrates, in particular in the tropical region. In contrast with other apicomplexans of the suborder Eimeriorina, the diversity and ecology of the species of the genus Calyptospora have been poorly investigated, resulting in a lacuna that restricts the understanding of the distribution and prevalence of this group of eukaryote microparasites in the Amazon region. In the present study, the integrated comparative analysis of morphological characteristics, histological and structural traits, and the sequences of a fragment of the 18S rRNA gene, provides support for the identification of a new species of Calyptospora, found parasitizing the hepatic tissue of the piscivorous blue peacock bass, Cichla piquiti, captured in the reservoir of the Estreito hydroelectric dam on the middle Tocantins River in northern Brazil. This new species was named Calyptospora paranaidji n. sp.     

Candidiasis: Predisposing Factors,Prevention, Diagnosis and Alternative Treatment

Candidiasis is the most common opportunistic yeast infection. Candida species and other microorganisms are involved in this complicated fungal infection, but Candida albicans continues to be the most prevalent. In the past two decades, it has been observed an abnormal overgrowth in the gastrointestinal, urinary and respiratory tracts, not only in immunocompromised patients, but also related to nosocomial infections and even in healthy individuals. There is a widely variety of causal factors that contribute to yeast infection which means that candidiasis is a good example of a multifactorial syndrome. Due to rapid increase in the incidence in these infections, this is the subject of numerous studies. Recently, the focus of attention is the treatment and, above all, the prevention of those complications. The diagnosis of candidiasis could become quite complicated. Prevention is the most effective “treatment,” much more than eradication of the yeast with antifungal agents. There are several aspects to consider in the daily routine that can provide a strength protection. However, a therapeutic approach is necessary when the infection is established, and therefore, other alternatives should be explored. This review provides an overview on predisposition factors, prevention and diagnosis of candidiasis, highlighting alternative approaches for candidiasis treatment.     

Fraying around the edges: negative effects of the invasive Tradescantia zebrina Hort. ex Bosse (Commelinaceae) on tree regeneration in the Atlantic Forest under different competitive and environmental conditions

Aims Invasive plants modify the structure and functioning of natural environments and threat native plant communities. Invasive species are often favored by human interference such as the creation of artificial forest edges. Field removal experiments may clarify if invasive plants are detrimental to native plant regeneration and how this is related to other local factors. We assessed the joint effect of environment and competition with the invasiveTradescantia zebrinaon tree species recruitment in an Atlantic Forest fragment.