Acute toxicity effects of ibuprofen on behaviour and haematological parameters of African catfish Clarias gariepinus (Burchell, 1822)

Indiscriminate discharge of pharmaceutical waste into the aquatic ecosystem may pose serious health challenges to aquatic biota. The effect of acute exposure to ibuprofen was evaluated using changes in behaviour and haematological parameters under static bio-assay method in Clarias gariepinus. Test specimens were exposed to acute concentrations of ibuprofen (0.28, 0.33, 0.38, 0.43 and 0.48 mg l^?1) for 24, 48, 72 and 96 h durations respectively. Behavioural and phenotypic changes were observed in surviving fish. There were significant (p < 0.05) concentration and duration-dependent increases in erythrocyte (RBC), haemoglobin (Hb), pack cell volume (PCV) and leukocytes (WBC) in treated fish compared to the control. Insignificant decreases (p > 0.05) in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were observed in treated fish compared to the control. Ibuprofen elicited dose and duration- dependent decrease in neutrophil counts with the decreases being significant (p < 0.05) in the higher doses of 0.43 and 0.48 mg l^?1. Ibuprofen did not elicit any significant changes in monocytes, basophils and eosinophils. Changes observed in this study showed that ibuprofen negatively affected the health of the fish and we recommend that discharge of ibuprofen into the aquatic environment should be monitored and controlled.     

Dysbiotic drift and biopsychosocial medicine: how the microbiome links personal,public and planetary health

The emerging concept of planetary health emphasizes that the health of human civilization is intricately connected to the health of natural systems within the Earth’s biosphere; here, we focus on the rapidly progressing microbiome science - the microbiota-mental health research in particular - as a way to illustrate the pathways by which exposure to biodiversity supports health. Microbiome science is illuminating the ways in which stress, socioeconomic disadvantage and social polices interact with lifestyle and behaviour to influence the micro and macro-level biodiversity that otherwise mediates health. Although the unfolding microbiome and mental health research is dominated by optimism in biomedical solutions (e.g. probiotics, prebiotics), we focus on the upstream psychosocial and ecological factors implicated in dysbiosis; we connect grand scale biodiversity in the external environment with differences in human-associated microbiota, and, by extension, differences in immune function and mental outlook. We argue that the success of planetary health as a new concept will be strengthened by a more sophisticated understanding of the ways in which individuals develop emotional connections to nature (nature relatedness) and the social policies and practices which facilitate or inhibit the pro-environmental values that otherwise support personal, public and planetary health.     

Volatility of internal eliminated segments in germ line genes of hypotrichous ciliates.

Germ line micronuclear genes in ciliated protozoa contain two types of interrupting sequences. Some genes contain introns, but internal eliminated segments (IESs) are much more prevalent. IESs are AT-rich DNA segments that separate macronucleus-destined segments (MDSs) in micronuclear genes. All IESs are excised and destroyed when a micronucleus develops into a macronucleus after each cell mating. IESs have no discernible function. Therefore, an investigation of the behavior of IESs in evolution has been undertaken to assess their possible significance. The IESs in the micronuclear gene encoding the beta-subunit of the telomere-binding protein (beta-TP) are not conserved in number, position, sequence, or length during the evolution of four oxytrichid ciliates. In contrast, the scrambled pattern of MDSs and IESs of the micronuclear actin I gene has been conserved during evolution; however, the precise positions, sequences, and lengths of the IESs differ among species, and in some organisms the actin I gene contains an additional IES and MDS. Corresponding IESs in the actin I genes among the different organisms have shifted positions by 1 to 14 bp, presumably by a mutation-shifting mechanism, creating differences in the repeat sequences flanking IESs. Thus, conservation of a particular repeat sequence among species is not required for IES excision. The changes in IES number and position in the beta-TP genes among ciliates are in sharp contrast to the stability of the intron position. Therefore, IESs are volatile, hypermutable elements that are inserted, removed, shifted, and modified continuously in the germ line through evolutionary time.     

Evolution of internal eliminated segments and scrambling in the micronuclear gene encoding DNA polymerase alpha in two Oxytricha species.

To learn about the evolution of internal eliminated segments (IESs) and gene scrambling in hypotrichous ciliates we determined the structure of the micronuclear (germline) gene encoding DNA polymerasealpha(DNA polalpha) in Oxytricha trifallax and compared it to the previously published structure of the germline DNA polalphagene in Oxytricha nova . The DNA polalphagene of O.trifallax contains 51 macronuclear-destined segments (MDSs) separated by 50 IESs, compared to 45 MDSs and 44 IESs in the O.nova gene. This means that IESs and MDSs have been gained and/or lost during evolutionary divergence of the two species. Most of the MDSs are highly scrambled in a similar non-random pattern in the two species. We present a model to explain how IESs, non-scrambled MDSs and scrambled MDSs may be added and/or eliminated during evolution. Corresponding IESs in the two species differ totally in sequence, and junctions between MDSs and IESs are shifted by 1-18 bp in O.trifallax compared to the O.nova gene. In both species a short region of the gene is distantly separated from the main part of the gene. Comparison of the gene in the two species shows that IESs and scrambling are highly malleable over evolutionary time.     

The metabolism of pyrimidine compounds by Tetrahymena pyriformis

The pyrimidine requirements for growth of T. pyriformis and for reversal of the growth inhibition caused by folate deprivation have been studied. The effects of thymidine and 5-fluorodeoxyuridine have been shown to be quantitatively different from the effects of these compounds on growth and the rate of DNA synthesis in mammalian cells. Labelled nucleosides added to the medium have been found to be converted to the corresponding bases with the exception of deoxycytidine, which is first deaminated to deoxyuridine. As a result no deoxynucleosides other than thymidine specifically label DNA. The results allow deductions to be made concerning the enzymes involved in pyrimidine utilization by this organism. It is suggested that pyrimidine utilization is always channeled through uracil in the case of those compounds that can supply the pyrimidine requirement for growth.     

Establishment and Maintenance of the Interferon-Induced Antiviral State: Studies in Enucleated Cells

Requirements for the physical presence of the cell's nucleus for the establishment and maintenance of the interferon-induced antiviral state were investigated. Enucleated chicken embryo fibroblasts were obtained by cytochalasin B treatment during centrifugation. The inhibition of vaccinia virus cytoplasmic DNA synthesis, monitored by autoradiography, was used to measure the antiviral activity resulting from interferon treatment. The antiviral state is not established in cells treated with interferon after removal of their nuclei. On the other hand, cells first treated with interferon for 6 or 12 h and then enucleated express the antiviral state. Furthermore, the antiviral state is maintained in enucleated cells for 16 h after enucleation. The antiviral state appears to be more stable in enucleates than in the residual nucleated cells found in the same cultures. Single cells of antiviral populations are found to be either fully permissive or fully restrictive to vaccinia DNA synthesis. The effect of an increasing intracellular multiplicity of infectious virus is to overcome the antiviral cell's block against viral DNA synthesis.