Expression of immune responsive genes in cell lines from two different Anopheline species

Malaria infection results in increased expression of immune responsive genes, including those encoding antimicrobial peptides such as Gambicin (Gam1) and Cecropin A (Cec1). Understanding how these genes are regulated will provide insights how the mosquito immune system is activated by Plasmodium. We previously have shown that Cec1 was primarily regulated by the Imd-Relish (REL2) pathway in the Anopheles gambiae Sua1B cell line. We show here that expression of Defensin A (Def1) and Gam1 was reduced after RNA interference against components of the Imd-REL2 pathway in An. gambiae cell lines. Interestingly, promoter reporters of these antimicrobial peptides were expressed at very low level in the cell line MSQ43 from Anopheles stephensi. Surprisingly, over-expression of either NF-kappaB transcription factor REL1 or REL2 alone is sufficient to induce the expression of Cec1, Gam1 and Def1. These results suggest that expression of these antimicrobial peptides (AMP) in vivo may be regulated by both the Toll and Imd pathways. We also show here for the first time that Tep4, a gene encoding a thioester containing protein, is regulated by REL2. Taken together, these results suggest that there are significant overlaps of genes regulated by the Toll-Rel1 and Imd-Rel2 pathways. Further, the different expression patterns in two different Anopheline cell lines provide a platform to identify other key positive and negative regulators of the antimicrobial peptide genes.

Espins and the actin cytoskeleton of hair cell stereocilia and sensory cell microvilli

The espins are novel actin-bundling proteins that are produced in multiple isoforms from a single gene. They are present at high concentration in the parallel actin bundle of hair cell stereocilia and are the target of deafness mutations in mice and humans. Espins are also enriched in the microvilli of taste receptor cells, solitary chemoreceptor cells, vomeronasal sensory neurons and Merkel cells, suggesting that espins play important roles in the microvillar projections of vertebrate sensory cells. Espins are potent actin-bundling proteins that are not inhibited by Ca2+. In cells, they efficiently elongate parallel actin bundles and, thereby, help determine the steadystate length of microvilli and stereocilia. Espins bind actin monomer via their WH2 domain and can assemble actin bundles in cells. Certain espin isoforms can also bind phosphatidylinositol 4,5-bisphosphate, profilins or SH3 proteins. These biological activities distinguish espins from other actin-bundling proteins and may make them well-suited to sensory cells.

A prospective study of respiratory ciliary structure and function after stem cell transplantation

We prospectively investigated the morphological and ciliary function abnormalities in 19 consecutive Chinese patients undergoing hemopoietic stem cell transplantation (HSCT) and studied their relationship with pulmonary complications. The percentage of structural ciliary abnormalities preceding HSCT was comparable to normal controls, but increased up to 1-year post-HSCT. However, the abnormalities did not correlate with ciliary or pulmonary function. Ciliary beat frequency (CBF) for patients undergoing autologous and allogeneic SCT was lower than that of matched controls, with a further decline at one year. There was, however, no significant change in pulmonary function for the whole cohort. There was considerable variation in CBF and ciliary abnormalities in all cases during 3-month interval assessments. Regular ciliary assessment did not predict the only two patients who eventually suffered from bronchiolitis obliterans (BO). We conclude that structural and functional ciliary abnormalities are common in recipients of HSCT, and predict post-HSCT deterioration. However, there is no evidence to show that CBF monitoring may be of prospective benefit.

Application of principal components analysis to 1H-NMR data obtained from propolis samples of different geographical origin

Propolis is a widely used natural remedy and a range of biological activities have been attributed to it. The chemical composition of propolis is highly variable and its quality is often controlled on the basis of one or two marker compounds. In order to progress towards a method for the quality control of this complex material, HPLC and 1H-NMR approaches as methods of quality control have been compared. HPLC analyses of 43 samples of propolis were carried out and six marker compounds were quantified in each sample. The same samples were analysed using 1H-NMR and the spectra were then converted into their first derivative forms and digitised using the software application MestRe-C. The digitised data were subjected to principal component analysis using the software application Simca-P. It was found that the chemical composition of propolis mapped well according to the geographical origins of the samples studied when the first three principal components were used to display them. In addition, each sample was assessed for anti-oxidant activity, and the results were then overlaid onto the sample groupings according to 1H-NMR data. It was observed that anti-oxidant properties also mapped quite well according to geographical origin.

NK cells do not mediate renal injury in murine adriamycin nephropathy

In adriamycin nephropathy (AN), a model of chronic proteinuric renal injury, the absence of functional B and T cells with residual natural killer (NK) cells, and macrophages in severe combined immunodeficient (SCID) mice results in more severe disease than in immunocompetent mice. We have recently shown expression of the stimulatory NK cell molecule NKG2D and its ligand RAE-1 in the adriamycin (ADR) kidney. Therefore, we sought to determine the role of NK cells in AN. We used anti-asialo GM1 NK cell depletion in immunocompetent BALB/c mice with AN, and also compared AN in immunodeficient SCID mice and immunodeficient nonobese diabetic (NOD)-SCID mice (that have impaired NK cell function). The number of NK cells was increased in AN in BALB/c mice compared with normal controls. NK cell depletion or reduction of NK function in NOD-SCID mice did not affect the severity of disease. In both wild type and immunodeficient models, ADR upregulated RAE-1 in the kidney. High levels of Class I major histocompatibility complex molecules were found in both models of AN. In conclusion, NK cells do not play a significant role in AN.

Julibroside J8-induced HeLa cell apoptosis through caspase pathway

The julibroside J8 was isolated from the Albizia julibrissin and evaluated for antiproliferatived on six cancer cell lines (BGC-823, Bel-7402, HeLa, PC-3MIE8, MDA-MB-435 and LH-60) in vitro. Julibroside J8 at 100 microg mL- 1 (46.08 micromol.L- 1) significantly inhibited growth in the first three cell lines. In addition, in HeLa cells typical apoptotic changes in morphology were observed, and further, nuclear damage was observed by Giemsa staining and DNA fragmentation was exhibited. Effects of julibrosideJ8 on induction of DNA fragmentation, caspase-3 activation and downregulation of ICAD expression were effectively inhibited by a caspase-3 inhibitor, z-DEVD-fmk. In addition, apoptosis induced with julibroside J8 was associated with an increase in expression of the apoptosis inducer Bax, and a significant reduction in expression of the apoptosis suppressor Bcl-2 in mitochondria. These results suggest that julibroside J8 induces HeLa death through caspase pathway.

ACognitive Approach to Game Usability and Design: Mental Model Development in Novice Real-Time Strategy Gamers

We developed a technique to observe and characterize a novice real-time-strategy (RTS) player's mental model as it shifts with experience. We then tested this technique using an off-the-shelf RTS game, EA Games Generals. Norman defined mental models as, "an internal representation of a target system that provides predictive and explanatory power to the operator." In the case of RTS games, the operator is the player and the target system is expressed by the relationships within the game. We studied five novice participants in laboratory-controlled conditions playing a RTS game. They played Command and Conquer Generals for 2 h per day over the course of 5 days. A mental model analysis was generated using player dissimilarity-ratings of the game's artificial intelligence (AI) agents analyzed using multidimensional scaling (MDS) statistical methods. We hypothesized that novices would begin with an impoverished model based on the visible physical characteristics of the game system. As they gained experience and insight, their mental models would shift and accommodate the functional characteristics of the AI agents. We found that all five of the novice participants began with the predicted physical-based mental model. However, while their models did qualitatively shift with experience, they did not necessarily change to the predicted functional-based model. This research presents an opportunity for the design of games that are guided by shifts in a player's mental model as opposed to the typical progression through successive performance levels.

Structural and functional insights into the AmtB/Mep/Rh protein family

X-ray crystallography revealed a similar architecture of the ammonium transport protein AmtB from Escherichia coli and the homologous protein Amt-1 from Archaeoglobus fulgidus. Furthermore, the atomic structures suggest that the proteins conduct ammonia (NH3) rather than ammonium ions (NH4+). These findings indicate that the more than 350 members of the ammonium transporter/methylamine permease/Rhesus (Amt/Mep/Rh) protein family found in archaea, bacteria, fungi, plants and animals are ammonia-conducting channels rather than ammonium ion transporters. The essential part of these proteins is the narrow hydrophobic ammonia-conducting pore with two highly conserved histidine residues located in the middle of the pore. A specific ammonium ion binding site is found at the extracellular entry site of E. coli AmtB. E. coli AmtB and its regulator GlnK form an effective ammonium sensory system that couples intracellular gene regulation by the nitrogen control system to external changes in ammonium availability. Based on structural and functional analysis of various mutants, two conserved histidine residues were found to be essential for substrate conductance also in the functional eukaryotic ammonium transporters. The next big challenge in the field surely is to determine the atomic structure of Rh proteins.

The dynamics and associations of airway neutrophilia post lung transplantation

Bronchoalveolar lavage (BAL) neutrophilia has been repeatedly observed in lung transplant recipients with established bronchiolitis obliterans syndrome (BOS). Little is known of the fluctuations in BAL and airway neutrophilic inflammation post-transplant. This prospective longitudinal study aimed to evaluate the dynamic changes of lung allograft neutrophils with time, immunosuppression, infection and BOS. A total of 28, initially healthy, BOS 0, lung transplant recipients underwent 134 bronchoscopic assessments, including BAL and endobronchial biopsies (EBB) (with immunohistochemistry) over 3-year follow up. Subsequently, 21 developed BOS 0p and 16 ultimately BOS. Compared to controls, there was early and persistent BAL neutrophilia (p < 0.05), contrasting with an initially normal EBB that shows a progressive increased airway wall neutrophil infiltrate. BAL neutrophilia (but not airway wall neutrophilia) was most striking when there was concomitant bronchopulmonary infection, particularly in the patients with BOS. Univariate and multivariate analyses suggested that BAL neutrophilia was linked to markers of infection while EBB neutrophilia was linked with coexistent inflammation with macrophages and lymphocytes.

IN CONCLUSION

(i) BAL neutrophilia is predominantly associated with infection; (ii) Airway wall neutrophilia (as monitored by EBB) increases with time post-transplant and is not associated with infection; (iii) By itself, BOS is not the major contributor to BAL and EBB neutrophilia.

Cytotoxicity and apoptosis induction of some selected marine bacteria metabolites

AIMS

To study the potential apoptosis effects of cytotoxic marine bacterial metabolites on human HeLa cell line.

METHODS AND RESULTS

After HeLa cells were routinely cultured, tetrazolium-based colorimetric assay for cytotoxicity was performed to screen the marine bacteria extracts showing 12 strains active. To find the potential active strain with apoptosis mechanism, a battery of apoptosis assays, including AO/EB staining, TUNEL assay (terminal-deoxynucleotidyl transferase mediated nick end labelling), gel electrophoresis and flow cytometry, were used to determine whether apoptosis was involved in HeLa cell cytotoxicity of marine bacterial extracts. The results indicated that four strains could induce cell shrinkage, cell membrane blebbing, formation of apoptotic body and DNA fragmentation.

CONCLUSIONS

Crude extracts of 12 of 153 strains of marine bacteria showed cytotoxic effects with ID50 ranged from 77.20 to 199.84 microg ml(-1), in which eight strains of bacteria were associated bacteria. The metabolites in the strains of QD1-2, NJ6-3-1, NJ1-1-1 and SS6-4 were able to induce HeLa cells apoptosis. Furthermore, the assessment by flow cytometry indicated that the hypodiploid apoptotic cells increased in a time-dependent manner, suggesting that induced apoptosis occurred from 24 h to 48 h after the extracts treatment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results suggested that the compounds from fermentation in these four marine bacterial strains could be candidates for developing apoptosis specific anti-tumour agents with lower toxicity. This study indicated that associated marine bacteria could be good source to find cytotoxic metabolites, and some cytotoxic marine bacterial metabolites could have apoptosis mechanisms.

DNA changes in barley (Hordeum vulgare) seedlings induced by cadmium pollution using RAPD analysis

In recent years, several plant species have been used as bioindicators, and several tests have been developed to evaluate the toxicity of environmental contaminants on vegetal organisms. In this study, barley (Hordeum vulgare L) seedling was used as bioindicator of cadmium (Cd) pollution in the range of 30-120 mgl(-1). Inhibition of root growth and reduction of total soluble protein content in root tips of barley seedlings were observed with the increase of Cd concentrations. The changes occurring in random amplified polymorphic DNA (RAPD) profiles of root tips following Cd treatment included variation in band intensity, loss of normal bands and appearance of new bands compared with the normal seedlings. Additionally, we found that the effect of changes was dose-dependent. These results indicated that genomic template stability (a qualitative measure reflecting changes in RAPD profiles) was significantly affected at the above Cd concentration. Thus, DNA polymorphisms detected by RAPD analysis could be used as an investigation tool for environmental toxicology and as a useful biomarker assay for the detection of genotoxic effects of Cd pollution on plants.

Contamination of shellfish from Shanghai seafood markets with paralytic shellfish poisoning and diarrhetic shellfish poisoning toxins determined by mouse bioassay and HPLC

This paper reports the results of investigations of shellfish toxin contamination of products obtained from Shanghai seafood markets. From May to October 2003, 66 samples were collected from several major seafood markets. Paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP) toxins in shellfish samples were monitored primarily by a mouse bioassay, then analysed by HPLC for the chemical contents of the toxins. According to the mouse bioassay, eight samples were detected to be contaminated by PSP toxins and seven samples were contaminated by DSP toxins. Subsequent HPLC analysis indicated that the concentrations of the PSP toxins ranged from 0.2 to 1.9 microg/100 g tissues and the main components were gonyautoxins 2/3 (GTX2/3). As for DSP, okadaic acid was detected in three samples, and its concentration ranged from 3.2 to 17.5 microg/100 g tissues. Beside okadaic acid, its analogues, dinophysistoxins (DTX1), were found in one sample. According to the results, gastropod (Neverita didyma) and scallop (Argopecten irradians) were more likely contaminated with PSP and DSP toxins, and most of the contaminated samples were collected from Tongchuan and Fuxi markets. In addition, the contaminated samples were always found in May, June and July. Therefore, consumers should be cautious about eating the potential toxic shellfish during this specific period.

Espin gene (ESPN) mutations associated with autosomal dominant hearing loss cause defects in microvillar elongation or organisation

BACKGROUND

Espins are actin bundling proteins present in hair cell stereocilia. A recessive mutation in the espin gene (Espn) has been detected in the jerker mouse and causes deafness, vestibular dysfunction, and hair cell degeneration. More recently mutations in the human espin gene (ESPN) have been described in two families affected by autosomal recessive hearing loss and vestibular areflexia.

OBJECTIVE

To report the identification of four additional ESPN mutations (S719R, D744N, R774Q, and delK848) in patients affected by autosomal dominant hearing loss without vestibular involvement.

RESULTS

To determine whether the mutated ESPN alleles affected the biological activity of the corresponding espin proteins in vivo, their ability to target and elongate the parallel actin bundles of brush border microvilli was investigated in transfected LLC-PK1-CL4 epithelial cells. For three mutated alleles clear abnormalities in microvillar length or distribution were obtained.

CONCLUSIONS

The results further strengthen the causative role of the espin gene in non-syndromic hearing loss and add new insights into espin structure and function.

Independent mutations in the Rdl locus confer dieldrin resistance to Anopheles gambiae and An. arabiensis

Substitutions of a conserved alanine residue in the Rdl locus coding for a gamma-aminobutyric acid (GABA) receptor subunit with serine or glycine confer resistance to dieldrin in various insect species. Here, we show that alanine to glycine substitution in the Rdl locus of the malaria vector, Anopheles gambiae, is genetically linked to resistance to dieldrin. An alanine to serine substitution developed independently in a dieldrin resistant strain of An. arabiensis. An allele-specific polymerase chain reaction (PCR) assay was able to differentiate dieldrin resistant and susceptible mosquitoes.

A hospital outbreak of Clostridium difficile disease associated with isolates carrying binary toxin genes

INTRODUCTION

The binary toxin genes cdt and cdtB have been detected in approximately 5% of Clostridium difficile strains. Severe C. difficile disease (CDD) may be associated with strains that carry the binary toxin genes.

METHODS

From April 2001 through March 2002, 8 severe and 41 nonsevere cases of nosocomial CDD were studied. Severe cases of CDD were defined by the presence of >or=2 of the following criteria: (1) abdominal pain, (2) a white blood cell count of >20,000 or <1500 cells/mm(3), and (3) ileus or bowel wall thickening with ascites. Underlying disease was assessed by 2 methods: a modified Horn score and the presence of comorbid conditions. The presence of cdtA, cdtB, and the toxin A and toxin B genes was determined, and molecular subtyping was performed.

RESULTS

All strains were positive for the toxin A and B genes, and 65.3% of the strains carried the cdtA and cdtB genes. Strains that carried the binary toxin genes accounted for 87.5% of the cases of severe CDD and 61.0% of the nonsevere cases (P=.23). Severity of CDD was not associated with either severe underlying disease or comorbid conditions. The strains that caused severe CDD belonged to 4 protein profile groups and >or=3 restriction endonuclease analysis (REA) groups. All (i.e., 5 of 5) strains in REA group BI, compared with none (i.e., 0 of 7) of the strains in REA group J carried the binary toxin genes (P=.001). Strains that belonged to REA groups BK and BR also carried the binary toxin genes.

CONCLUSIONS

The binary toxin genes were present in nearly two-thirds of the C. difficile strains, and they were correlated with the REA group. Severity of CDD was not closely associated with a specific clone or underlying disease, but it may be associated with the presence of the binary toxin genes. Larger studies are needed to discern whether a true association exists and whether the binary toxin alters the pathogenicity of the C. difficile strain.