Nitric oxide production by Biomphalaria glabrata haemocytes: effects of Schistosoma mansoni ESPs and regulation through the extracellular signal-regulated kinase pathway

BACKGROUND: Schistosoma mansoni uses Biomphalaria glabrata as an intermediate host during its complex life cycle. In the snail, the parasite initially transforms from a miracidium into a mother sporocyst and during this process excretory-secretory products (ESPs) are released. Nitric oxide (NO) and its reactive intermediates play an important role in host defence responses against pathogens. This study therefore aimed to determine the effects of S. mansoni ESPs on NO production in defence cells (haemocytes) from schistosome-susceptible and schistosome-resistant B. glabrata strains. As S. mansoni ESPs have previously been shown to inhibit extracellular signal-regulated kinase (ERK) phosphorylation (activation) in haemocytes from susceptible, but not resistant, B. glabrata the regulation of NO output by ERK in these cells was also investigated. RESULTS: Haemocytes from resistant snails challenged with S. mansoni ESPs (20 mug/ml) over 5 h displayed an increase in NO production that was 3.3 times greater than that observed for unchallenged haemocytes; lower concentrations of ESPs (0.1-10 mug/ml) did not significantly increase NO output. In contrast, haemocytes from susceptible snails showed no significant change in NO output following challenge with ESPs at any concentration used (0.1-20 mug/ml). Western blotting revealed that U0126 (1 muM or 10 muM) blocked the phosphorylation (activation) status of ERK in haemocytes from both snail strains. Inhibition of ERK signalling by U0126 attenuated considerably intracellular NO production in haemocytes from both susceptible and resistant B. glabrata strains, identifying ERK as a key regulator of NO output in these cells. CONCLUSION: S. mansoni ESPs differentially influence intracellular NO levels in susceptible and resistant B. glabrata haemocytes, possibly through modulation of the ERK signalling pathway. Such effects might facilitate survival of S. mansoni in its intermediate host

'Schistosoma mansoni' excretory-secretory products from miracidium to sporocyst stage and their effects on 'Biomphalaria glabrata' defence cells

The processes through which parasites are able to survive in their susceptible host are complex and not fully understood. The platyhelminth parasite, ‘Schistosoma mansoni’, completes part of its life cycle in the snail ‘Biomphalaria glabrata’. During its intra-molluscan development, the parasite produces excretory-secretory products (ESPs), a cocktail of uncharacterised proteins and lipids. ‘Schistosoma mansoni’ ESPs may play a role in modulating snail-host immune responses. Two laboratory strains of ‘B. glabrata’ were used in this study; a schistosome-susceptible strain (NHM1742) and a schistosome-resistant strain (NHM 3017) refractory to infection. Snail haemocytes, the main type of circulating defence cells, which have similar characteristics to macrophages, were investigated. The extracellular signal-regulated kinase (ERK) signalling pathway is known to regulate defence reactions in cells. Activated ERK-like proteins were identified in ‘B. glabrata’ haemocytes using phosphor-specific anti-ERK antibodies. The phosphorylation (or activation) of ERK was reduced by 60% in susceptible snail haemocytes following ‘S. mansoni’ ESP exposure (20 [mu]g/ml for 1 h). In contrast, resistant snail haemocytes did not exhibit any changes in phosphorylated ERK levels following ESP-challenge. Nitric oxide (NO), a reactive molecule, which plays a role in host defence mechanisms, increased 3.3 fold in resistant snail haemocytes when challenged with ESPs. ESP-challenged susceptible snail haemocytes did not show any significant modulation in NO levels. The use of scanning electron microscopy also highlighted an increase in haemocyte spreading (on glass coverslips) in ESP-challenged haemocytes from resistant snails only. Heat shock protein 70 (HSP70), an evolutionarily conserved protein with immune-modulation properties was investigated using western blotting and scanning confocal microscope using anti-HSP70 antibodies. HSP70 was significantly reduced in susceptible (P[less than or equal to]0.01) and resistant (P[less than or equal to]0.05) snail haemocytes following 1 h exposure to 20 [mu]g/ml ESPs. Interestingly, the ERK cell signalling pathway was found to coordinate both NO and HSP70 levels, as the ERK inhibitor, U0126, significantly reduced levels NO output and HSP70 expression in ‘B. glabrata’ haemocytes. Finally, haemocyte gene expression was analysed after ESP-challenge using a ‘B. glabrata’ cDNA microarray. The microarray analysis highlighted differentially expressed genes (DEGs) between ESP exposed resistant and susceptible snail haemocytes. These DEGs transcribe proteins involved in protein degradation, protein transcription, cell-to-cell interaction and immune responses. This study has broadened our knowledge on the differences that exist between resistant and susceptible ‘B. glabrata’ haemocytes and their differential response to ‘S. mansoni’ ESPs; providing important insights into snail-schistosome interactions

The Impact of work-life connectivity on professional women: A case study of telecom industry

The purpose of this research was to test work life border theory against job/life satisfaction. The impact of work-life connectivity on professional women working in telecom industry was checked. This quantitative research was conducted by collecting secondary data gathered through world recognized questionnaires. A sample size of 285 respondents was collected through Qualtrics and self-administered questionnaires. This sample was adequate as using Power and Precision software a minimum sample of 175 was computed. Cluster sampling technique in combination with stratified sampling was used to collect data from women in Telecom Industry from major cities of Pakistan. Data collected was analyzed in SPSS and SEM was run on AMOS. Pearson r correlation and regression tests were run to study the effect of the understudy variables. The study found that both types of connectivity, work- to- family and family- to-work directly influence job and family satisfaction of women. The results suggest that family-friendly policies and organizational support can bring substantial benefits to women workers and the organization as a whole

Disruption of ERK signalling in Biomphalaria glabrata defence cells by Schistosoma mansoni: implications for parasite survival in the snail host

Biomphalaria glabrata is an intermediate snail host for the human blood fluke Schistosoma mansoni. To survive in B. glabrata, S. mansoni must suppress the snail's haemocyte-mediated defence response; the molecular mechanisms by which this is achieved remain largely unknown. We report here that S. mansoni excretory-secretory products (ESPs) attenuate phosphorylation of extracellular signal-regulated kinase (ERK) in haemocytes from a B. glabrata strain susceptible to S. mansoni. Whole S. mansoni sporocysts also impair ERK signalling in these cells. In striking contrast, ERK signalling in haemocytes from a B. glabrata strain refractory to schistosome infection is unaffected by ESPs or sporocysts. Effects of ESPs on ERK are similar in the presence or absence of snail plasma, thus ESPs seem to affect haemocytes directly. These findings reveal novel schistosome interference mechanisms; as ERK regulates various haemocyte defence reactions, we propose that disruption of ERK signalling in haemocytes facilitates S. mansoni survival within susceptible B. glabrata

Comparison of the QuikRead go® point-of-care faecal immunochemical test for haemoglobin with the FOB Gold Wide® laboratory analyser to diagnose colorectal cancer in symptomatic patients

Objectives Faecal immunochemical testing for haemoglobin (FIT) is used to triage patients for colonic investigations. Point-of-care (POC) FIT devices on the market have limited data for their diagnostic accuracy for colorectal cancer (CRC). Here, a POC FIT device is compared with a laboratory-based FIT system using patient collected samples from the urgent referral pathway for suspected CRC. Methods A prospective, observational cohort study. Patients collected two samples from the same stool. These were measured by POC QuikRead go® (Aidian Oy, Espoo, Finland) and laboratory-based FOB Gold Wide® (Sentinel Diagnostics, Italy). Faecal haemoglobin <10 μg haemoglobin/g of faeces was considered as negative. At this threshold, comparisons between the two systems were made by calculating percentage agreement and Cohen’s kappa coefficient. Proportion of negative results were compared with Chi squared testing. Sensitivities for CRC were calculated. Results A total of 629 included patients provided paired samples for FIT to compare the QuikRead go® and FOB Gold Wide®. The agreement around the negative threshold was 83.0% and Cohen’s kappa coefficient was 0.54. The QuikRead go® reported 440/629 (70.0% of samples) as negative compared to 523/629 (83.1%) for the FOB Gold Wide®, this difference was significant (p-value<0.001). Sensitivities for CRC detection by the QuikRead go® and FOB Gold Wide® were 92.9% (95% confidence interval (CI): 68.5–98.7%) and 100% (CI: 78.5–100%) respectively. Conclusions Both systems were accurate in their ability to detect CRC. Whilst good agreement around the negative threshold was identified, more patients would be triaged to further colonic investigation if using the QuikRead go®

Differences in the gene expression profiles of Haemocytes from Schistosome-susceptible and -resistant Biomphalaria glabrata exposed to Schistosoma mansoni excretory-secretory products.

During its life cycle, the helminth parasite Schistosoma mansoni uses the freshwater snail Biomphalaria glabrata as an intermediate host to reproduce asexually generating cercariae for infection of the human definitive host. Following invasion of the snail, the parasite develops from a miracidium to a mother sporocyst and releases excretory-secretory products (ESPs) that likely influence the outcome of host infection. To better understand molecular interactions between these ESPs and the host snail defence system, we determined gene expression profiles of haemocytes from S. mansoni-resistant or -susceptible strains of B. glabrata exposed in vitro to S. mansoni ESPs (20 μg/ml) for 1 h, using a 5K B. glabrata cDNA microarray. Ninety-eight genes were found differentially expressed between haemocytes from the two snail strains, 57 resistant specific and 41 susceptible specific, 60 of which had no known homologue in GenBank. Known differentially expressed resistant-snail genes included the nuclear factor kappa B subunit Relish, elongation factor 1α, 40S ribosomal protein S9, and matrilin; known susceptible-snail specific genes included cathepsins D and L, and theromacin. Comparative analysis with other gene expression studies revealed 38 of the 98 identified genes to be uniquely differentially expressed in haemocytes in the presence of ESPs, thus identifying for the first time schistosome ESPs as important molecules that influence global snail host-defence cell gene expression profiles. Such immunomodulation may benefit the schistosome, enabling its survival and successful development in the snail host

Effects of hydrated sodium calcium aluminum silicates (HSCAS) in experimentally induced cadmium toxicity in male Japanese quail (Coturnix japonica)

Cadmium (Cd) is an environmental pollutant and is toxic to animal species. The objective of this study was to evaluate the toxico-pathological effects of Cd and the effects of hydrated sodium calcium aluminum silicates (HSCAS) on Cd-induced pathological alterations in male Japanese quails (Coturnix japonica). A total of 180 male C. japonica at 25 d of age were divided into nine equal groups, i.e. A–I. Group A was kept as control while groups B and C were administered with Cd @ 100 and 200 mg/kg feed. Groups D and E were fed HSCAS @ 5 and 10 g/kg feed. Groups F, G, H, and I were administered with HSCAS along with Cd in different combinations. The total duration of the experiment was 35 d (at experimental day 0, bird age was 21 d). Gross changes in Cd-fed groups included enlargement of the liver and atrophied testes. Histopathological picture of groups B (100 mg Cd/kg) and C (200 mg Cd/kg) showed fatty change, individual cell necrosis, and proliferation of bile ducts at hepatic triad. Testes showed testicular degeneration which included absence of spermatogenesis, pyknotic, and dark nuclei between the spermatids and absence of spermatids and spermatozoa. No parameter studied showed any adverse effect of HSCAS given to the quail @ 5 and 10 g/kg feed. Groups of quail-fed Cd and HSCS concurrently in different combinations did not show any adverse effect suggesting an amelioration of Cd-induced pathological changes in the birds. It was concluded that concurrent administration of HSCAS and Cd protected the quail from adverse effects of Cd toxicity

Genes differentially expressed between haemocytes from schistosome-resistant and -susceptible <i>B. glabrata</i> exposed to <i>S. mansoni</i> ESPs.

<p>Only genes with known homologues are shown. Each bar represents the mean (±SD) normalised expression for the identified differentially expressed gene (p≤0.05, n = 4). A positive value indicates the gene is expressed in susceptible snail haemocytes whereas a negative value indicates the gene is expressed in resistant snail haemocytes. Multiple genes matching the same protein are shaded in a similar colour.</p