Investigation of yeast genes possibly involved in mtDNA stability using the nematode Caenorhabditis elegans

Screening of Caenorhabditis elegans genes possibly involved in the mitochondrial genome maintenance was performed using our previous validated method of RNAi combined with ethidium bromide. This was to knock down C. elegans genes homologous to yeast genes known to be involved in mtDNA stability but of unknown molecular function or to identify transient components that could play important role on the stability of mtDNA in a temporal and/or spatial manner. C. elegans homologs for 11 genes among 27 yeast genes for which deletion leads to a rho0 state were found, however, only 5 genes were present in the RNAi library. Out of these 5 genes, 1 gene (homolog of GEM1) gave a clear L3 arrest on RNAi and ethidium bromide indicating its involvement on mtDNA stability. Four other genes homologs of MTG2, YER087W, AVL9 and RRG3 did not lead to L3 arrest even though their deletion in Saccharomyces cerevisiae leads to rho0 state. Although MTG2 has been reported to be important in the function and structure on mtDNA stability in yeast, our results did not support those findings in C. elegans. The human homolog of this gene (MIRO1) can be considered as a candidate gene involved in mtDNA stability and sequenced in patients with mtDNA depletion diseases.Keywords: mtDNA, Caenorhabditis elegans, nucleoid, RNAi, candidate genes, homolog, MIRO

Gene expression clines reveal local adaptation and associated trade-offs at a continental scale

Local adaptation, where fitness in one environment comes at a cost in another, should lead to spatial variation in trade-offs between life history traits and may be critical for population persistence. Recent studies have sought genomic signals of local adaptation, but often have been limited to laboratory populations representing two environmentally different locations of a species' distribution. We measured gene expression, as a proxy for fitness, in males of Drosophila subobscura, occupying a 20° latitudinal and 11 °C thermal range. Uniquely, we sampled six populations and studied both common garden and semi-natural responses to identify signals of local adaptation. We found contrasting patterns of investment: transcripts with expression positively correlated to latitude were enriched for metabolic processes, expressed across all tissues whereas negatively correlated transcripts were enriched for reproductive processes, expressed primarily in testes. When using only the end populations, to compare our results to previous studies, we found that locally adaptive patterns were obscured. While phenotypic trade-offs between metabolic and reproductive functions across widespread species are well-known, our results identify underlying genetic and tissue responses at a continental scale that may be responsible for this. This may contribute to understanding population persistence under environmental change

The genome of the seagrass Zostera marina reveals angiosperm adaptation to the sea

Seagrasses colonized the sea(1) on at least three independent occasions to form the basis of one of the most productive and widespread coastal ecosystems on the planet(2). Here we report the genome of Zostera marina (L.), the first, to our knowledge, marine angiosperm to be fully sequenced. This reveals unique insights into the genomic losses and gains involved in achieving the structural and physiological adaptations required for its marine lifestyle, arguably the most severe habitat shift ever accomplished by flowering plants. Key angiosperm innovations that were lost include the entire repertoire of stomatal genes(3), genes involved in the synthesis of terpenoids and ethylene signalling, and genes for ultraviolet protection and phytochromes for far-red sensing. Seagrasses have also regained functions enabling them to adjust to full salinity. Their cell walls contain all of the polysaccharides typical of land plants, but also contain polyanionic, low-methylated pectins and sulfated galactans, a feature shared with the cell walls of all macroalgae(4) and that is important for ion homoeostasis, nutrient uptake and O-2/CO2 exchange through leaf epidermal cells. The Z. marina genome resource will markedly advance a wide range of functional ecological studies from adaptation of marine ecosystems under climate warming(5,6), to unravelling the mechanisms of osmoregulation under high salinities that may further inform our understanding of the evolution of salt tolerance in crop plants(7)

Clinical and microbiological predictors of healing in Buruli ulcer disease.

INTRODUCTION: Wound measurements are relevant in monitoring the rate of healing (RoH) and may predict time to healing. Predicting the time to healing can help improve the management of Buruli ulcer. We examine three methods for the determination of RoH and their use as predictors of time to healing. METHODS: Lesion measurements of Buruli ulcer patients treated from 2007 to 2022 were obtained with acetate sheet tracings (2D) or Aranz software (3D) fortnightly. RoH was determined using the absolute area, percentage area reduction and linear methods at 4 weeks post onset of antibiotic treatment. Predicted time to healing was compared to the actual healing time. Baseline characteristics were assessed for associations with healing. RESULTS: All three methods for calculating the RoH significantly distinguished between fast and slow healers (p < 0.0001). The predicted healing time using the linear method was comparable to the actual healing time for fast healers (p = 0.34). The RoH was influenced by the form of lesion, with plaques [OR 2.19 5 %CI (1.2-3.6), p = 0.009], and oedemas [OR 8.5; 95 %CI (1.9--36.9), p = 0.004] being associated with delayed healing. The proportion of patients with paradoxical reactions 16 % vs 3 %, p < 0.0001), higher baseline bacterial load (75/104;72 % vs 21/47;45 %, p = 0.001) and delayed clearance of viable organisms (71/104;68 % vs 9/47;19 %, p < 0.0001) was higher in the slow healers than the fast healers. CONCLUSION: Predicted healing rates were comparatively lower for slow healers than fast healers. Baseline characteristics associated with healing can be explored for an improved disease management plan to reduce patient and caregiver anxiety

Improved protocols for isolation of Mycobacterium ulcerans from clinical samples

Background The isolation and culture of Mycobacterium ulcerans (Mu) as a primary diagnostic modality for Buruli ulcer (BU) disease are limiting due to their low sensitivity and slow-growing nature. M. ulcerans cultures can also be overgrown with other bacteria and fungi. Culture, however, remains an important tool for the study of persisting viable M. ulcerans, drug susceptibility tests, and other molecular assays to improve management of the disease. The challenge of contamination with other fast-growing bacteria necessitates decontamination of clinical samples prior to culturing, but current methods may be too harsh, resulting in low yields of M. ulcerans. We aimed to evaluate a Tika-Kic decontamination process for M. ulcerans that uses supplements to stimulate M. ulcerans growth to improve recovery. Methods Swab and Fine Needle Aspirate (FNA) samples were collected from 21 individuals with confirmed BU at baseline (week 0) and weeks 2 and 4 after initiating antibiotic treatment. Samples were decontaminated with Tika-Kic decontamination medium and the modified Petroff (NaOH) methods then inoculated each into Mycobacterium Growth Indicator Tube (MGIT) or Löwenstein Jensen (LJ) medium. Time to growth detection and confirmation by qPCR as well as the proportion of positive cultures for all three methods and the proportion of positive cultures for all three time points were documented. Common contaminating bacteria were also isolated and identified. Results The proportion of M. ulcerans positive cultures obtained was higher for Tika-MGIT samples [14/43 (32%)] compared to Petroff-MGIT samples [10/43 (23%)] and Petroff-LJ samples [8/43 (19%)]. Baseline samples had a higher isolate proportion [17 (53%)] compared to samples collected after treatment initiation [9 (28%) for week 2 and 6 (19%) for week 4]. Contaminating bacteria isolated include Burkholderia cepacia, Pseudomonas aeruginosa, Pasteurella pneumotropica, Proteus mirabilis, Morganella morganii, Staphylococcus aureus and Enterococcus. Conclusion Our study shows an advantage for culturing Mycobacterium ulcerans from clinical samples using the Tika-Kic decontamination and growth medium. Further research is needed to refine sample processing to improve M. ulcerans recovery

Oral health related behaviors among adult Tanzanians: a national pathfinder survey

<p>Abstract</p> <p>Background</p> <p>The oral health education programs which have been organised and delivered in Tanzania were not based on a thorough understanding of behaviours which influence oral health. Therefore, evaluation of these programs became difficult. This study aimed at investigating the oral health related behaviours and their determinants among Tanzanian adults.</p> <p>Methods</p> <p>A national pathfinder cross sectional survey was conducted in 2006 involving 1759 respondents from the six geographic zones of mainland Tanzania. Frequency distributions, Chi square and multiple logistic regression analyses were performed using SPSS version 13.0.</p> <p>Results</p> <p>The rates of abstinence from alcohol for the past 30 days and life time smoking were 61.6% and 16.7% respectively, with males being more likely to smoke (OR 9.2, CI 6.3 -12.9, p < 0.001) and drink alcohol (OR 1.5, CI 1.2 -1.8, p < 0.001). Multiple regression analysis revealed that; having dental pain (OR 0.7, CI 0.5-0.8; p < 0.001) and being minimally educated (OR 0.48, CI 0.4-0.6; p < 0.001) reduced the likelihood of having a high sugar score. Whereas being male (OR 1.5, CI 1.2- 1.8; p < 0.001), urban (OR 1.9, CI 1.5 -2.3; p < 0.001), and young (OR 1.5, CI 1.2 -1.8; p < 0.001) increased the likelihood of having a high sugar score. Urban residents were less likely to take alcohol (OR 0.7, CI 0.6-0.9; p < 0.01), or smoke cigarette (OR = 0.7, CI = 0.6-0.9); less likely to be those who do not use fruits (OR 0.3, CI 0.2-0.4; p < 0.001); dental clinic (OR 0.5, CI 0.4-0.7; p < 0.001); factory made tooth brushes (OR 0.1, CI 0.08-0.17; p < 0.001) and toothpaste (OR 0.1, CI 0.1-0.2; p < 0.001) than their rural counterparts. More rural (13.2%) than urban (4.6%) residents used charcoal.</p> <p>Conclusion</p> <p>The findings of this study demonstrated social demographic disparities in relation to oral health related behaviors, while dental pain was associated with low consumption of sugar and high likelihood to take alcohol.</p

Poverty, dirt, infections and non-atopic wheezing in children from a Brazilian urban center

BACKGROUND: The causation of asthma is poorly understood. Risk factors for atopic and non-atopic asthma may be different. This study aimed to analyze the associations between markers of poverty, dirt and infections and wheezing in atopic and non-atopic children. METHODS: 1445 children were recruited from a population-based cohort in Salvador, Brazil. Wheezing was assessed using the ISAAC questionnaire and atopy defined as allergen-specific IgE ≥ 0.70 kU/L. Relevant social factors, environmental exposures and serological markers for childhood infections were investigated as risk factors using multivariate multinomial logistic regression. RESULTS: Common risk factors for wheezing in atopic and non-atopic children, respectively, were parental asthma and respiratory infection in early childhood. No other factor was associated with wheezing in atopic children. Factors associated with wheezing in non-atopics were low maternal educational level (OR 1.49, 95% CI 0.98-2.38), low frequency of room cleaning (OR 2.49, 95% CI 1.27-4.90), presence of rodents in the house (OR 1.48, 95% CI 1.06-2.09), and day care attendance (OR 1.52, 95% CI 1.01-2.29). CONCLUSIONS: Non-atopic wheezing was associated with risk factors indicative of poverty, dirt and infections. Further research is required to more precisely define the mediating exposures and the mechanisms by which they may cause non-atopic wheeze

Magnitude and Complexity of Rectal Mucosa HIV-1-Specific CD8+ T-Cell Responses during Chronic Infection Reflect Clinical Status

The intestinal mucosa displays robust virus replication and pronounced CD4+ T-cell loss during acute human immunodeficiency virus type 1 (HIV-1) infection. The ability of HIV-specific CD8+ T-cells to modulate disease course has prompted intensive study, yet the significance of virus-specific CD8+ T-cells in mucosal sites remains unclear.We evaluated five distinct effector functions of HIVgag-specific CD8+ T-cells in rectal mucosa and blood, individually and in combination, in relationship to clinical status and antiretroviral therapy (ART). In subjects not on ART, the percentage of rectal Gag-specific CD8+ T-cells capable of 3, 4 or 5 simultaneous effector functions was significantly related to blood CD4 count and inversely related to plasma viral load (PVL) (p<0.05). Polyfunctional rectal CD8+ T-cells expressed higher levels of MIP-1beta and CD107a on a per cell basis than mono- or bifunctional cells. The production of TNFalpha, IFN-gamma, and CD107a by Gag-specific rectal CD8+ T-cells each correlated inversely (p<0.05) with PVL, and MIP-1beta expression revealed a similar trend. CD107a and IFN-gamma production were positively related to blood CD4 count (p<0.05), with MIP-1beta showing a similar trend. IL-2 production by rectal CD8+ T-cells was highly variable and generally low, and showed no relationship to viral load or blood CD4 count.The polyfunctionality of rectal Gag-specific CD8+ T-cells appears to be related to blood CD4 count and inversely related to PVL. The extent to which these associations reflect causality remains to be determined; nevertheless, our data suggest a potentially important role for mucosal T-cells in limiting virus replication during chronic infection

DNA methylation patterns in bladder cancer and washing cell sediments: a perspective for tumor recurrence detection

<p>Abstract</p> <p>Background</p> <p>Epigenetic alterations are a hallmark of human cancer. In this study, we aimed to investigate whether aberrant DNA methylation of cancer-associated genes is related to urinary bladder cancer recurrence.</p> <p>Methods</p> <p>A set of 4 genes, including <it>CDH1 </it>(E-cadherin), <it>SFN </it>(stratifin), <it>RARB </it>(retinoic acid receptor, beta) and <it>RASSF1A </it>(Ras association (RalGDS/AF-6) domain family 1), had their methylation patterns evaluated by MSP (Methylation-Specific Polymerase Chain Reaction) analysis in 49 fresh urinary bladder carcinoma tissues (including 14 cases paired with adjacent normal bladder epithelium, 3 squamous cell carcinomas and 2 adenocarcinomas) and 24 cell sediment samples from bladder washings of patients classified as cancer-free by cytological analysis (control group). A third set of samples included 39 archived tumor fragments and 23 matched washouts from 20 urinary bladder cancer patients in post-surgical monitoring. After genomic DNA isolation and sodium bisulfite modification, methylation patterns were determined and correlated with standard clinic-histopathological parameters.</p> <p>Results</p> <p><it>CDH1 </it>and <it>SFN </it>genes were methylated at high frequencies in bladder cancer as well as in paired normal adjacent tissue and exfoliated cells from cancer-free patients. Although no statistically significant differences were found between <it>RARB </it>and <it>RASSF1A </it>methylation and the clinical and histopathological parameters in bladder cancer, a sensitivity of 95% and a specificity of 71% were observed for <it>RARB </it>methylation (Fisher's Exact test (p < 0.0001; OR = 48.89) and, 58% and 17% (p < 0.05; OR = 0.29) for <it>RASSF1A </it>gene, respectively, in relation to the control group.</p> <p>Conclusion</p> <p>Indistinct DNA hypermethylation of <it>CDH1 </it>and <it>SFN </it>genes between tumoral and normal urinary bladder samples suggests that these epigenetic features are not suitable biomarkers for urinary bladder cancer. However, <it>RARB </it>and <it>RASSF1A </it>gene methylation appears to be an initial event in urinary bladder carcinogenesis and should be considered as defining a panel of differentially methylated genes in this neoplasia in order to maximize the diagnostic coverage of epigenetic markers, especially in studies aiming at early recurrence detection.</p