Polyfunctional Type-1, -2, and -17 CD8+ T Cell Responses to Apoptotic Self-Antigens Correlate with the Chronic Evolution of Hepatitis C Virus Infection

Caspase-dependent cleavage of antigens associated with apoptotic cells plays a prominent role in the generation of CD8⁺ T cell responses in various infectious diseases. We found that the emergence of a large population of autoreactive CD8⁺ T effector cells specific for apoptotic T cell-associated self-epitopes exceeds the antiviral responses in patients with acute hepatitis C virus infection. Importantly, they endow mixed polyfunctional type-1, type-2 and type-17 responses and correlate with the chronic progression of infection. This evolution is related to the selection of autoreactive CD8⁺ T cells with higher T cell receptor avidity, whereas those with lower avidity undergo prompt contraction in patients who clear infection. These findings demonstrate a previously undescribed strict link between the emergence of high frequencies of mixed autoreactive CD8⁺ T cells producing a broad array of cytokines (IFN-γ, IL-17, IL-4, IL-2…) and the progression toward chronic disease in a human model of acute infection.     

In vitro insect-feeding bioassay to determine the resistance of transgenic rice plants transformed with insect resistance genes against striped stem borer (Chilo suppressalis)

Summary To determine the degree of insect resistance in transgenic plants, different bioassays are used which typically use either whole plant or small pieces of leaves or stems of transgenic plants, following culture under greenhouse conditions. An in vitro insect-feeding bioassay is presented which permits the infestation of transgenic plantlets with newly hatched larvae from the striped stem borer. The bioassay consists of the germination of rice seeds in vitro using Murashige and Skoog medium in test tubes, and then infestation of each 3–4 cm long seedling with one neonate larva obtained from surfacesterilized eggs of Chilo suppressalis. The infested in vitro plantlets are kept in culture rooms at 25°C for several days and then the seedling damage and the growth of the larvae are analyzed. Senia (japonica variety) homozygous transgenic rice plants were used for these experiments. The plants were transformed with either the cry1B or the maize proteinase inhibitor (mpi) genes. Both genes confer resistance to Chilo suppressalis. With non-transformed plants the larvae grew and developed normally, feeding on the small rice plantlets. In contrast, with cry1B plants, the neonate larvae died during the first days of the infestation. These plantlets recovered completely and developed similarly to the non-infested control plants. With transgenic plants transformed with the mpi gene, the neonate larvae did not die but grew more slowly compared with the controls. Thus, this in vitro insect-feeding bioassay is a rapid and easy method to detect the resistance of cry and mpi transgenic plants to stem borers such as Chilo suppressalis.     

A historical review of research on the weaver ant Oecophylla in biological control

1 Although the weaver ant Oecophylla is the first written record of biological control, dating from 304 ad , there have been fewer than 70 scientific publications on this predator as a biological control agent in Asia, from the early 1970s onwards, and fewer than 25 in Africa. 2 Apart from crop‐specific ecological and perceptual factors, a historical review shows that political and market forces have also determined the extent to which Oecophylla was incorporated into research and development programmes. 3 In Africa, research on weaver ants in biological control concentrated on export crops, such as coconut and cocoa, whereas, in Asia and Australia, research focused on fruit and nut crops, primarily destined for domestic markets. 4 Increased evidence of pesticide inefficiency under tropical smallholder conditions, changing paradigm shifts in participatory research and a growing scientific interest in local knowledge in the early 1990s opened up new avenues for research on conservation biological control. 5 Lobbying and advocacy have been needed to ensure that Oecophylla was recognized as an effective biological control agent. 6 With an increased market demand for organic produce, holistic approaches such as conservation biological control, particularly the use of Oecophylla, are increasing in importance. 7 Multi‐stakeholder strategies for collaborative learning are proposed for a better control of major fruit, nut and timber tree pests in Africa, Asia and Australia.     

Extreme differences in rates of molecular evolution of foraminifera revealed by comparison of ribosomal DNA sequences and the fossil record

Foraminifera have one of the best known fossil records among the unicellular eukaryotes. However, the origin and phylogenetic relationships of the extant foraminiferal lineages are poorly understood. To test the current paleontological hypotheses on evolution of foraminifera, we sequenced about 1,000 base pairs from the 3' end of the small subunit rRNA gene (SSU rDNA) in 22 species representing all major taxonomic groups. Phylogenies were derived using neighbor- joining, maximum-parsimony, and maximum-likelihood methods. All analyses confirm the monophyletic origin of foraminifera. Evolutionary relationships within foraminifera inferred from rDNA sequences, however, depend on the method of tree building and on the choice of analyzed sites. In particular, the position of planktonic foraminifera shows important variations. We have shown that these changes result from the extremely high rate of rDNA evolution in this group. By comparing the number of substitutions with the divergence times inferred from the fossil record, we have estimated that the rate of rDNA evolution in planktonic foraminifera is 50 to 100 times faster than in some benthic foraminifera. The use of the maximum-likelihood method and limitation of analyzed sites to the most conserved parts of the SSU rRNA molecule render molecular and paleontological data generally congruent.      

Use of dissolved ozone for controlling planktonic and sessile bacteria in industrial cooling systems

Cooling water treatment requires effective, environmentally-safe biocides compatible with system operation. The unique combination of high biocidal activity during use with no toxic discharge, could render dissolved ozone a safe biocide for cooling water treatment. Planktonic and sessile cells of Pseudomonas fluorescens (a frequent microbial contaminant of industrial systems) were used in this work to assess the biocidal effectiveness of ozone. Dissolved ozone showed to be effective at concentrations between 0.1 and 0.3 ppm, to eliminate completely the levels of planktonic cells used in this paper (10⁷–10⁸ cell/ml) within a range of contact times between 10 and 30 min. However, ozone at 0.15 ppm was only able to diminish sessile cell population by two or three orders of magnitude. This minor biocidal effectiveness of ozone against bacterial biofilms is discussed in this paper, taking into account recent concepts on structure and dynamics of biofilms. Different metallic substrata were assayed to verify if there was any effect of metal nature on the biocidal action. Open circuit potentials vs. time experiments and potentiodynamic polarization curves were made for assessing the effect of dissolved ozone on the corrosion behavior of the metals tested.     

Effects of copper ions released from metallic copper on CHO-K1 cells

The aim of this study was to investigate the cytotoxic and genotoxic effect of copper extracts obtained from metallic copper in Chinese hamster ovary (CHO-K1) cell line using neutral red (NR), sister chromatid exchange (SCE), chromosomal aberrations (CA) and cell-cycle kinetics tests. Cells were cultured in Ham-F10 with different copper-containing extracts obtained after the immersion of copper disks for 1, 2, 3, 9, 12, 24, 48 and 72 h in culture medium. Results from cytotoxicity assay showed an inverted U-shape response evidenced in changes in lysosomal activity and mitotic index. The analysis of CA revealed an increase of abnormal metaphases for copper concentration (cCu) in the 5.67-7.42 mg/L dose-range (p<0.001). In addition, SCE frequencies were higher for treated cells when compared with controls in the 1.56-7.42 mg/L concentration range (p<0.001). The absence of metaphases indicated cytotoxicity for cCu≥10.85 mg/L. Results show that cells close to copper-containing materials releasing copper ions are susceptible to cytotoxic and genotoxic effects.     

Global transcriptional response of pig brain and lung to natural infection by Pseudorabies virus

Background  

Pseudorabies virus (PRV) is an alphaherpesviruses whose native host is pig. PRV infection mainly causes signs of central nervous system disorder in young pigs, and respiratory system diseases in the adult.     

Defining the healthy "core microbiome" of oral microbial communities

Background  

Most studies examining the commensal human oral microbiome are focused on disease or are limited in methodology. In order to diagnose and treat diseases at an early and reversible stage an in-depth definition of health is indispensible. The aim of this study therefore was to define the healthy oral microbiome using recent advances in sequencing technology (454 pyrosequencing).