Biological effects of marine contaminated sediments on Sparus aurata juveniles

Chemical analysis of the compounds present in sediment, although informative, often is not indicative of the downstream biological effects that these contaminants exert on resident aquatic organisms. More direct molecular methods are needed to determine if marine life is affected by exposure to sediments. In this study, we used an aquatic multi-species microarray and q-PCR to investigate the effects on gene expression in juvenile sea bream (Sparus aurata) of two contaminated sediments defined as sediment 1 and 2, respectively, from marine areas in Northern Italy. Both sediments affected gene expression as evidenced by aquatic multi-species microarray analysis and q-PCR. Exposure of S. aurata juveniles to sediment 1 and sediment 2 altered expression of genes that are biomarkers for endocrine disruption. There were differences between the effects of sediment 1 and sediment 2 on gene expression in S. aurata juveniles indicating that the chemicals in the two sediments had different physiological targets. These results suggest that the classification of sediment solely on the basis of specific chemical profiles is inadequate, and not a true indicator of its potential to cause harmful effects. Our data also indicate that integration of physiochemical analysis and bioassays for monitoring the downstream harmful effects on aquatic organisms are required to gain a complete understanding of the effects of sediment on aquatic life.

ZD6474, a small molecule tyrosine kinase inhibitor, potentiates the anti-tumor and anti-metastasis effects of radiation for human nasopharyngeal carcinoma

PURPOSE

To investigate the capacity for ZD6474, a small molecule tyrosine kinase inhibitor, to enhance anti-tumor and anti-metastasis effects of radiation on human nasopharyngeal carcinoma (NPC).

EXPERIMENTAL DESIGN

NPC cell lines and xenograft models were evaluated following treatment with ZD6474 and radiation alone and in combination compared with untreated control mice.

RESULTS

Treatment with ZD6474 enhanced the anti-proliferative effect of radiation on NPC cell lines as detected by cell proliferation and apoptosis assays. ZD6474 also induced a significant increase in the radiosensitivity of NPC cells, with radiation enhancement ratios (RERs) ranging from 1.2 to 1.6. Despite the cytotoxicity exhibited by NPC cells following radiotherapy, the invasion and migration of NPC cells was found to be unaffected. In contrast, treatment with ZD6474 strongly inhibited the invasion and migration of NPC cells. When the administration of radiation and ZD6474 was investigated in vitro, the ability of ZD6474 to inhibit activation of the pro-survival signaling pathways induced by radiation was demonstrated. In vivo, ZD6474 significantly enhanced the anti-metastasis effects of radiation, while treatment with radiation and ZD6474 was found to be well tolerated and resulted in a strong inhibition of tumor growth.

CONCLUSIONS

Our results suggest the combination of radiation and ZD6474 represents a promising strategy for the treatment of human NPC.

Power generation in MFCs with architectures based on tubular cathodes or fully tubular reactors

Tubular cathodes provide a method to obtain high surface areas for scaling up microbial fuel cells (MFCs), but the importance of the cathode shape is not known. We therefore examined power production using cathodes in various configurations (tubes or flat). The MFC with a single internal carbon cloth tube cathode (71 W/m(3)) produced more power than previously obtained with an ultrafiltration membrane (8 W/m(3)) due to the better performance of carbon material. This power density was slightly less than that of a flat carbon cloth cathode (81 W/m(3); 88 m(2)/m(3)) due to the lower total surface area of the tube (68 m(2)/m(3)) and not as a result of the tubular cathode shape. Adding a second tube increased power (83 W/m(3)) in proportion to specific surface area (93 m(2)/m(3)). Wrapping the cathode completely around the anode formed a fully tubular MFC (external tubular reactor) with a higher surface area that produced 128 W/m(3). Volumetric power density was highly correlated with cathode specific surface area (R(2) = 0.93, p = 0.008) and did not depend on the cathode shape (tubes, completely tubular, or flat). Thus, future MFC designs should focus on increasing cathode specific surface area.

Evidence for Photochemical Formation of H2O2 and Oxidation of SO2 in Authentic Fog Water

When samples of rain and fog water were exposed to ultraviolet and visible light, reactive transients such as hydrogen peroxide were formed and dissolved organic matter and sulfur dioxide were depleted. These results, in conjunction with those from previous studies, imply that dissolved organic compounds and transition metals such as iron ions are involved in the photochemical formation of hydrogen peroxide and other photooxidants in atmospheric waters.

Heparin inhibits P388D1 cells adherence and metastasis to peripheral lymph nodes in vitro and in vivo

Heparin is known to attenuate tumor metastasis mainly by inhibiting the interaction between L-selectin and its ligand. However, the mechanism of heparin on lymphoma is unclear. This report demonstrates that both L-selectin/h IgG chimeric protein and heparin treatment can significantly inhibit the adhesion of P388D1 cells onto lymphatic sinusoids and marginal sinusoids in vitro, that heparin can attenuate P388D1 cell homing to lymph nodes in vivo at 12 hours, and that heparin significantly reduced P388D1 cells metastasis to lymph nodes 18 days after injection. These results indicate that heparin may act as a ligand for L-selectin on the P388D1 macrophage-like lymphoma cell line to attenuate tumor growth and metastasis.

Optimal two-stage design for case-control association analysis incorporating genotyping errors

Two-stage design is a cost effective approach for identifying disease genes in genetic studies and it has received much attention recently. In general, there are two types of two-stage designs that differ on the methods and samples used to measure allele frequencies in the first stage: (1) Individual genotyping is used in the first stage; (2) DNA pooling is used in the first stage. In this paper, we focus on the latter. Zuo et al. (2006) investigated statistical power of such a design, among other things, but the cost of the study was not taken into account. The purpose of this paper is to study the optimal design under the given overall cost. We investigate how to allocate the resources to the two stages. Note that in addition to the measurement errors associated with DNA pooling, genotyping errors are also unavoidable with individual genotyping. Therefore, we discuss the optimal design combining genotyping errors associated with individual genotyping. The joint statistical distributions of test statistics in the first and second stages are derived. For a fixed cost, our results show that the optimal design requires no additional samples in the second stage but only that the samples in the first stage be re-used. When the second stage uses an entirely independent sample, however, the optimal design under a given cost depends on the population allele frequency and allele frequency difference between the case and control groups. For the current genotyping costs, we can roughly allocate 1/3 to 1/2 of the total sample size to the first stage for screening.

Bicarbonate concentration as affected by soil water content controls iron nutrition of peanut plants in a calcareous soil

Strategy I peanut plants are frequently subjected to iron deficiency when growing in calcareous soils, which contain high concentrations of bicarbonate. In calcareous soils under field conditions, it has been noted that chlorosis increases in severity after excessive rainfall or irrigation, but the chlorosis symptoms of peanuts are alleviated after waterlogged soils dry. A pot experiment was conducted simulating the chlorosis symptom observed in the field when peanut plants are exposed to fluctuating soil water content induced from rainfall or irrigation. We investigated the bicarbonate fluctuations resulting from adjustable soil water content (SWC) that could lead to bicarbonate-induced iron chlorosis of peanuts growing in calcareous soil. The experiments included three treatments of SWC (50% of water holding capacity (WHC), 80% of WHC, and 100% of WHC) under two levels of CaCO(3) concentrations (at 8.67% and 18.67%.) The results showed that the iron nutrition of peanuts could be regulated by different SWC at both CaCO(3) levels. Our observations indicate that iron deficiency chlorosis symptoms in peanuts grown in high soil water content were more severe, compared to those of peanuts in lower soil water content. A shift from high soil water content to lower soil water content could improve or eliminate the iron deficiency chlorosis symptom of peanuts. The HCO(3)(-) concentration in the peanut rhizosphere increased with increasing SWC and CaCO(3) content and it correlated with the level of soil water content. We suggest that variations in the soil water content could induce HCO(3)(-) concentration variation in the rhizosphere of peanuts. Consequently, the high HCO(3)(-) concentration, which is induced by a high water content in calcareous soil and a high CaCO(3) level, could inhibit the physiological response to iron deficiency of peanuts, resulting in iron deficiency chlorosis. The study indicates that a reasonable agricultural practice of irrigation and drainage should be considered to improve and prevent iron deficiency chlorosis of strategy I plants in calcareous soil.

Out of the Smokescreen: does an anti-smoking advertisement affect young women's perception of smoking in movies and their intention to smoke?

OBJECTIVE

To evaluate the effect of an anti-smoking advertisement on young women's perceptions of smoking in movies and their intention to smoke. SUBJECTS/ SETTING: 2038 females aged 12-17 years attending cinemas in New South Wales, Australia. DESIGN/ INTERVENTION: Quasi-experimental study of patrons, who were surveyed after having viewed a movie at their local cinema. The control group was surveyed during week 1 and the intervention group, during week 2. Before seeing the movie in week 2, a 30 second anti-smoking advertisement was shown, which featured a well known female actor drawing attention to the prevalence of smoking in movies.

OUTCOMES

Attitude of current smokers and non-smokers to smoking in the movies; intention of current smokers and non-smokers to be smoking in 12 months time.

RESULTS

Among non-smokers, 48.2% of the intervention subjects thought that the smoking in the movie they viewed was "not OK" compared with 28.3% of the control subjects (p < 0.0001). However, there was no difference among smokers in the intervention (26.4%) and control (16.9%) groups (p = 0.28). A higher percentage of current smokers in the intervention group indicated they were unlikely to smoke in 12 months time (47.8%) than smokers in the control condition (31.9%) (p = 0.03). For non-smokers, there was no difference in smoking intentions between conditions, with 95% saying they would be unlikely to be smoking in 12 months time.

CONCLUSIONS

This "real world" study suggests that placing an anti-smoking advertisement before movies containing smoking scenes can help to "immunise" young women against the influences of film stars smoking.

Anaerobic bio-hydrogen production using pre-heated river sediments as seed sludge

Anaerobic bio-hydrogen production is the focus in the field of bio-energy resources. In this paper, a series of batch experiments were conducted to investigate the effects of several factors on anaerobic bio-hydrogen producing process carried out by pre-heated river sediments. The results showed that several factors such as substrate and its concentration, temperature and the initial pH value could affect the anaerobic bio-hydrogen production in different levels. At 35 degrees C and the initial pH of 6.5, using glucose of 20,000 mg COD/L as substrate, the highest hydrogen production of 323.8 ml-H2/g TVS in a 100 ml batch reactor was reached, the specific hydrogen production rate was 37.7 ml-H2/g TVS h, and the hydrogen content was 51.2%. Thereafter using the same pre-heated river sediments as seed sludge, continuous anaerobic bio-hydrogen production was achieved successfully in a lab-scale CSTR with gas-separator. At the organic loading rate of 36 kg COD/m3 d, the highest hydrogen production was 6.3-6.7 l-H2/l-reactor d, the specific hydrogen production was 1.3-1.4 mol-H2/mol-glucose, and the hydrogen content in the gas was 52.3%. The effluent of the bio-reactor contained some small molecular organics, mainly including ethanol, acetate, butyrate and their molar proportion is 1:1:0.6.

[Observation on the clinical symptoms and sporocyst excretion in human volunteers experimentally infected with Sarcocystis hominis]

AIM

To investigate the excretion of sporocysts and clinical manifestations in humans experimentally infected of Sarcocystis hominis.

METHODS

Three volunteers were infected by eating raw beef containing cysts of S. hominis. One ingested about 1,567 cysts in skeletal muscles of a naturally infected cattle; two volunteers each ingested about 14,740 cysts from an experimentally infected water buffalo meat. Fecal examination by zinc sulfate flotation method was conducted daily since d4 postinfection (pi).

RESULTS

Free sporocysts and oocysts were found in their faeces from d11-40, d12-23, d10-30 pi, and peaked at d18, d14, d14. All of them presented clinical symptoms such as abdominal pain, distension, watery diarrhea and eosinophilia 1 wk approximately 4 wk pi and were spontaneously cured within 29 days pi without taking any medicine.

CONCLUSION

All the experimentally infected persons had gastrointestinal symptoms and passed sporocysts and oocysts in faeces 10-12 days after infection and persisted for 11-29 days.

Dual action of n-alcohols on neuronal nicotinic acetylcholine receptors

Alcohol is known to modulate the activity of a variety of neuroreceptors and ion channels. Recently, neuronal nicotinic acetylcholine receptors (nnAChRs) have become a specific focus of study because not only are they potently modulated by alcohol but also they regulate the release of various transmitters, including gamma-aminobutyric acid (GABA) and dopamine, which play an important role in the behavioral effects of ethanol. Whereas the potency of normal alcohols (n-alcohols) to potentiate GABA(A) receptors and to inhibit N-methyl-D-aspartate receptors increases with carbon chain length, we have found that n-alcohols, depending on the carbon chain length, exert a dual action, potentiation and inhibition, on nnAChRs in primary cultured rat cortical neurons. The mechanism of dual action of n-alcohols on nnAChRs was further analyzed using human embryonic kidney cells expressing the alpha 4 beta 2 subunits. Shorter chain alcohols from methanol to n-propanol potentiated acetylcholine (ACh)-induced currents, whereas longer chain alcohols from n-pentanol to n-dodecanol inhibited the currents. n-Butanol either potentiated or inhibited the currents depending on the concentrations of ACh and butanol. The parameters for both potentiation (log EC(200)) and inhibition (log IC(50)) were linearly related to carbon number, albeit with different slopes. The slope for potentiation was -0.299, indicating a change in free energy change (Delta Delta G) of 405 cal/mol/methylene group, whereas the slope for inhibition was -0.584, indicating a Delta Delta G of 792 cal/mol. These results suggest that potentiating and inhibitory actions are exerted through two different binding sites. Ethanol decreased the potency of n-octanol to inhibit ACh currents, possibly resulting from an allosteric mechanism.

Separation and determination of flavonoids and other phenolic compounds in cranberry juice by high-performance liquid chromatography

A HPLC method was developed for the separation and determination of flavonoid and phenolic antioxidants in cranberry juices. Free flavonoid and phenolic compounds were fractionated into neutral and acidic groups by means of a solid-phase extraction method, followed by subsequent HPLC separations. Combined flavonoids and phenolics were hydrolyzed by acid before HPLC analysis. This developed method provides a fast and high resolution of individual flavonoid and phenolic compounds. In cranberry fruit, flavonoids and phenolic acids exist predominantly in combined forms, such as glycosides and esters. A total of 400 mg of total flavonoids and phenolic compounds/l of sample was found in a freshly squeezed cranberry juice, which was distributed as about 44% of phenolic acids and 56% of flavonoids. Benzoic acid was the major phenolic compound. Major flavonoids in the freshly squeezed cranberry juice were quercetin and myricetin.

[A study on bacterial contamination of dental handpieces]

OBJECTIVE

The aim of this study is to evaluate the effects of different factors, including concentration of the bacterial suspension, number of stops set on handpieces, and different disinfectants, on bacterial contamination of handpieces and their clinical significance.

METHODS

Bacterial contamination of 20 handpieces were analyzed in different concentration of bacterial suspension, number of stops set on handpieces and after using different out surface disinfectants.

RESULTS

Statistical increment (P < 0.05) of handpieces inside contamination was observed relevant to increment of the bacterial suspension concentration. No statistical relevance was seen between handpiece inside contamination and the number of stops set on handpieces(P > 0.05). Disinfection with different disinfectants significantly decreased out surface contamination(P < 0.05), but no statistical change of bacteria (P > 0.05) was observed inside handpieces.

CONCLUSION

As the concentration of bacterial suspension is the key factor affecting the inside contamination of handpieces, oral cavity cleanness is essential before dental therapy. The surface disinfection of handpieces is necessary after dental therapy, but cannot prevent cross-contamination between patients.

Modulation of neuronal nicotinic acetylcholine receptors by halothane in rat cortical neurons

Inhalational general anesthetics have recently been shown to inhibit neuronal nicotinic acetylcholine (ACh) receptors (nnAChRs) expressed in Xenopus laevis oocytes and in molluscan neurons. However, drug actions on these systems are not necessarily the same as those seen on native mammalian neurons. Thus, we analyzed the detailed mechanisms of action of halothane on nnAChRs using rat cortical neurons in long-term primary culture. Currents induced by applications of ACh via a U-tube system were recorded by the whole-cell, patch-clamp technique. ACh evoked two types of currents, alpha-bungarotoxin-sensitive, fast desensitizing (alpha 7-type) currents and alpha-bungarotoxin-insensitive, slowly desensitizing (alpha 4 beta 2-type) currents. Halothane suppressed alpha 4 beta 2-type currents more than alpha 7-type currents with IC(50) values of 105 and 552 microM, respectively. Halothane shifted the ACh dose-response curve for the alpha 4 beta 2-type currents in the direction of lower ACh concentrations and slowed its apparent rate of desensitization. The rate of recovery after washout from halothane block was much faster than the rate of recovery from ACh desensitization. Thus, the halothane block was not caused by receptor desensitization. Chlorisondamine, an irreversible open channel blocker for nnAChRs, caused a time-dependent block that was attenuated by halothane. These results could be accounted for by kinetic simulation based on a model in which halothane causes flickering block of open channels, as seen in muscle nAChRs. Halothane block of nnAChRs is deemed to play an important role in anesthesia via a direct action on the receptor and an indirect action to suppress transmitter release.

The frequency of common skin conditions in preschool-age children in Australia: atopic dermatitis

OBJECTIVE

To determine the prevalence and severity of atopic dermatitis in a stratified cross-section of preschool-age children examined throughout Victoria, Australia.

DESIGN

A cross-sectional skin survey using a selected cluster sample of the various centers throughout Victoria.

SETTING

The study population included Victorian children attending child-care centers, preschools, and Maternal and Child Health Centres, with the reference population being Australian children aged 5 years and younger.

PARTICIPANTS

Of 1634 potential participants, 1116 children (68.3%) were examined.

INTERVENTION

A dermatologist performed a total skin examination, including head and neck, limbs, and trunk, on all children. The diaper area was examined in children younger than 12 months.

MAIN OUTCOME MEASURE

All parents were administered a questionnaire to elicit demographic information, history of skin conditions, and family history of skin problems or related diseases. The examiner recorded the presence, site, and severity of atopic dermatitis for calculation of age- and sex-specific prevalence rates.

RESULTS

The age- and sex-adjusted point prevalence was 30.8% (95% confidence interval [CI], 28.0%-33.5%). Most children (63.7%) were classified as having minimal or mild disease. Only 5.8% of children with atopic dermatitis did not have face or flexural involvement. Of the 237 children with atopic dermatitis and information available, 209 used 1 or more products to treat their condition.

CONCLUSIONS

Atopic dermatitis is common, decreasing in prevalence after the first 3 years of life. Most children have mild disease requiring little if any treatment, and much could be prevented with simple measures. Educational programs directed at those caring for preschool-age children that provide information on simple preventive measures, where practical, and sources of advice for treatment, if necessary, could substantially reduce the morbidity of this condition in predisposed children.

Exoribonuclease superfamilies: structural analysis and phylogenetic distribution

Exoribonucleases play an important role in all aspects of RNA metabolism. Biochemical and genetic analyses in recent years have identified many new RNases and it is now clear that a single cell can contain multiple enzymes of this class. Here, we analyze the structure and phylogenetic distribution of the known exoribonucleases. Based on extensive sequence analysis and on their catalytic properties, all of the exoribonucleases and their homologs have been grouped into six superfamilies and various subfamilies. We identify common motifs that can be used to characterize newly-discovered exoribonucleases, and based on these motifs we correct some previously misassigned proteins. This analysis may serve as a useful first step for developing a nomenclature for this group of enzymes.

[Expression of c-jun, c-fos and MDM2 mRNA in cultured kerotinocytes through transfecting HPV16]

OBJECTIVE

To study the expression of c-jun, c-fos and MDM2 mRNA in cultured kerotinocytes through transfecting HPV16.

METHODS

Keratinocytes were cultured in serum-free medium, and secondary cultures continued in a suitable time. Plasmid pSV(2)-neo/HPV16 was transfected into cultured kerotinocytes using FuGENE(TM)6. Reverse-transcriptase polymerase chain reaction (RT-PCR) was used to detect c-jun, c-fos and MDM2 mRNA in keratinocytes of normal and transfected keratinocytes.

RESULTS

After transfection, the morphology and structure of the keratinocytes were changed. The cells became larger and their nuclei became looser. There were particles in the cytoplasm. The expression of HPV16 mRNA was detected in the keratinocytes after transfecting pSV(2)-neo/HPV16 and the product was 110 bp fragment. The DNA fragment (7.9 kb) of HPV16 was also detected. In the transfected keratinocytes, the exprssions of c-jun, c-fos and MDM2 mRNA were detected and the products were 196 bp, 332 bp and 548 bp fragments, respectively. However, the above-mentioned expressions those were not detected in normal keratinocytes.

CONCLUSION

HPV leads to cell proliferation by expressing c-jun, c-fos and MDM2.

A tetravalent single-chain antibody-streptavidin fusion protein for pretargeted lymphoma therapy

Single-chain Fv antibody fragments from the CD20-specific murine monoclonal antibody B9E9 were genetically engineered as streptavidin fusions [single-chain Fv-streptavidin (scFvSA) fusion protein] for use in pretargeted radioimmunotherapy. The scFvSA constructs were expressed as soluble, tetrameric species in the periplasm of Escherichia coli. Expression levels were affected by the order of the variable regions and the length and composition of the single-chain Fv linker. The best expressor was obtained with the variable regions in the heavy chain-light chain configuration separated by a 25-mer Gly4Ser linker. This construct produced 250-300 mg of soluble, tetrameric fusion protein per liter of fermentor culture. The fusion protein (Mr 173,600) was purified from crude lysates by iminobiotin affinity chromatography with an overall yield of about 50% and was analyzed for functionality both in vitro and in vivo. Immunoreactivity of the scFvSA fusion protein and its nanomolar affinity to CD20-positive Ramos cells were comparable with the B9E9 monoclonal antibody. The fusion protein had a biotin dissociation rate identical to recombinant streptavidin and bound an average of 3.6 biotins/molecule of a possible 4 biotins/molecule. Labeled fusion protein cleared from the blood of BALB/c mice with a P half-life of about 16 h. In nude mice bearing Ramos xenografts, the fusion protein demonstrated sufficient tumor localization of functional streptavidin to enable efficient, tumor-specific targeting of a subsequently administered radionuclide-chelate/biotin molecule. These results suggest that large quantities of functional scFvSA can be produced for clinical testing as a therapy for non-Hodgkin's lymphoma.

[Identification of cry-type genes of 31 Bacillus thuringiensis isolates and analysis of their expression product]

In this study, cry-type gene of 31 isolates of Bt had been identified using PCR-RFLP identification system, and SDS-PAGE analysis and bioassay had been performed. 25 strains containing cry1 type gene express 130-150 kD protein and 16 of them contain cry1I gene, which codes 80 kD protein and is larvicidal to both lepidopteran and coleopteran species. 15 strains contain both cry1 and cry2 type gene; 10 strains contain unknown cry-type gene; 6 strains don't contain seven identified cry-type gene. Result of bioassay shows that the strains containing both cry1 and cry2 gene have high toxicity to lepidopteran order, 7 of them are strongly insecticidal to Pristiphora beijingensis and Lymantria dispar larvae; the strains containing cry1Ab + 1Ac + 2A or cry1Aa + 1Ac + 2A have high activity to Heliothis armigera; no cry gene, no activity. It is indicated that identification of cry-type gene and its analysis of SDS-PAGE protein can predict insecticidal activity of Bt isolates, and it is no pertinency between cry-type gene and serotype of Bt strain.

The frequency of common nonmalignant skin conditions in adults in central Victoria, Australia

BACKGROUND

Nonmalignant skin conditions are believed to be common in adults, although there are very few community-based studies to determine their exact frequency.

OBJECTIVE

To record the prevalence of common, nonmalignant skin conditions in adults in central Victoria, Australia.

METHODS

A total of 1457 respondents from a random selection of adults aged 20 years and over from Maryborough, central Victoria, were given a total body examination by a dermatologist or dermatology trainee. People with any nail or skin signs suggestive of tinea had scrapings taken for fungal culture.

RESULTS

The age- and sex-adjusted prevalence of warts was 7.1% (95% confidence interval (CI), 5.8-8.4%), acne 12.8% (95% CI, 11.0-14.5%), atopic dermatitis 6.9% (95% CI, 5.6-8.3%), seborrheic dermatitis 9. 7% (95% CI, 8.2-11.2%), asteatotic dermatitis 8.6% (95% CI, 7.1-10. 0%), psoriasis 6.6% (95% CI, 5.7-7.9%), culture-positive tinea 12% (95% CI, 10.3-13.6%), seborrheic keratoses 58.2% (95% CI, 55.6-60. 7%), and Campbell de Morgan spots (cherry angiomas) 54.4% (95% CI, 51.9-57.0%). There was variation in the prevalence of many of these conditions with age.

CONCLUSIONS

This study demonstrates that nonmalignant skin conditions are common in adults in Australia. Their diagnosis and management represent a considerable burden not only to those suffering from the conditions, but also to the health system which provides for their care.

The DNase activity of RNase T and its application to DNA cloning

RNase T is one of eight distinct 3'-->5' exoribonucleases present in Escherichia coli. The enzyme plays an important role in stable RNA metabolism, including tRNA end turnover and 3' maturation of most stable RNAs because it is the only RNase that can efficiently remove residues near a double-stranded (ds) stem. In the course of study of its specificity and mechanism, we found that RNase T also has single-strand-specific DNase activity. Purified RNase T degrades both single-stranded (ss)RNA and ssDNA in a non-processive manner. However, in contrast to its action on RNA, RNase T binds ssDNA much more tightly and shows less sequence specificity. As with RNA, DNA secondary structure strongly affects its degradation by RNase T. Thus, RNase T action on a dsDNA with a single-stranded 3'-extension efficiently generates blunt-ended DNA. This property of RNase T suggested that it might be a useful enzyme for blunt-ended DNA cloning. We show here that RNase T provides much higher cloning efficiency than the currently used mung bean nuclease.

SSA/Ro antigen expressed on membrane of UVB-induced apoptotic keratinocytes is pathogenic but not detectable in supernatant of cell culture

OBJECTIVES

To better understand the potential effect of ultraviolet light on the photosensitivity of patients with lupus erythematosus (LE), to elucidate the mechanisms of SSA/Ro antibody formation after UV exposure, and to investigate the role of this autoantibody in the pathogenesis of skin lesions.

METHODS

Primary human keratinocytes were cultured in Medium-154. After ultraviolet-B light (UVB) irradiation, the keratinocytes were treated with affinity-purified anti-SSA/Ro sera and stained with FITC-labeled goat-anti-human IgG and propidium iodide (PI), followed by enzyme digestion with RNase, RNase-free DNase or RNase plus DNase. As target cells, the irradiated keratinocytes were incubated with affinity-purified anti-SSA/Ro sera, with or without fresh human sera as complement. The supernatants of irradiated keratinocytes were analyzed with ELISA method for SSA/Ro antigens.

RESULTS

UVB irradiation induced apoptotic blebs on the cell surface. The blebs were composed of ribonucleoproteins and contained SSA/Ro antigens. SSA/Ro antigens expressed on UVB irradiated keratinocytes bound to affinity-purified anti-SSA/Ro sera, leading to complement-dependent cytotoxicity. However, no SSA/Ro antigens were detected in the supernatants.

CONCLUSIONS

SSA/Ro, a ribonucleoprotein antigen expressed on UVB irradiated keratinocytes, may be recognized and presented to immune cells by a direct cell-cell contact other than be eliminated into the circulation.

Prenatal alcohol use and offspring size at 10 years of age

The Maternal Health Practices and Child Development Project is a longitudinal study of the effects of prenatal exposure to alcohol and other substances. Women were selected from a prenatal clinic and interviewed at the 4th and 7th months of pregnancy. Their offspring were examined at delivery, at 8 and 18 months, and at 3, 6, and 10 years. This report examined 610 offspring, at age 10, who were exposed prenatally to alcohol. Most alcohol use in this low-income cohort was light to moderate, although the entire spectrum of alcohol use is represented. The weight, length, head circumference, and skinfold thickness of the offspring were measured. At each assessment phase, we found a significant association between size and prenatal exposure to alcohol. At age 10, the children who were prenatally exposed to alcohol continued to be significantly smaller in weight, height, head circumference, and skinfold thickness. These results indicate that prenatal alcohol exposure has a long-term impact on offspring growth.

Identification of a receptor-binding pocket on the envelope protein of friend murine leukemia virus

Based on previous structural and functional studies, a potential receptor-binding site composed of residues that form a pocket at one end of the two long antiparallel helices in the receptor-binding domain of Friend 57 murine leukemia virus envelope protein (RBD) has been proposed. To test this hypothesis, directed substitutions for residues in the pocket were introduced and consequences for infection and for receptor binding were measured. Receptor binding was measured initially by a sensitive assay based on coexpression of receptor and RBD in Xenopus oocytes, and the findings were confirmed by using purified proteins. Three residues that are critical for both binding and infection (S84, D86, and W102), with side chains that extend into the pocket, were identified. Moreover, when mCAT-1 was overexpressed, the infectivity of Fr57-MLV carrying pocket substitutions was partially restored. Substitutions for 18 adjacent residues and 11 other previously unexamined surface-exposed residues outside of the RBD pocket had no detectable effect on function. Taken together, these findings support a model in which the RBD pocket interacts directly with mCAT-1 (likely residues, Y235 and E237) and multiple receptor-envelope complexes are required to form the fusion pore.

Flagellar duplication and migration during the Trichomonas vaginalis cell cycle

Trichomonas vaginalis is a flagellated protozoan, a representative of 1 of the earliest known eukaryotic lineages. Trichomonas vaginalis lacks centrioles but possesses basal bodies. We report here the cell cycle-dependent flagellar dynamics of T. vaginalis. By immunofluorescence, we found that T. vaginalis flagella duplicated during S-phase, segregated toward the nuclear poles, and then emanated from the spindle poles at mitosis. This behavior strongly parallels that of centrioles and other spindle pole-associated structures variously termed centrosomes, spindle pole bodies, or microtubule organizing centers. These observations support the hypothesis that flagellar forces may have provided motile forces for spindle pole alignment in an ancestral eukaryote.

The vacB gene required for virulence in Shigella flexneri and Escherichia coli encodes the exoribonuclease RNase R

vacB, a gene previously shown to be required for expression of virulence in Shigella and enteroinvasive Escherichia coli, has been found to encode the 3'-5' exoribonuclease, RNase R. Thus, cloning of E. coli vacB led to overexpression of RNase R activity, and partial deletion or interruption of the cloned gene abolished this overexpression. Interruption of the chromosomal copy of vacB eliminated endogenous RNase R activity; however, the absence of RNase R by itself had no effect on cell growth. In contrast, cells lacking both RNase R and polynucleotide phosphorylase were found to be inviable. These data indicate that RNase R participates in an essential cell function in addition to its role in virulence. The identification of the vacB gene product as RNase R should aid in understanding how the virulence phenotype in enterobacteria is expressed and regulated. On the basis of this information we propose that vacB be renamed rnr.

[The experimental study of Pseudomonas contamination in soft drinks]

Bymeans of this study, we have found out about the situation of Pseudomons contamination in the soft drinks which are manufactured and sold at the area of Nanchang City. In the course of this study, we examined total 416 specimens, in which we found that 69 specimens were positive reaction. The positive rate made up 16.59% of the total specimens. From these 69 positive specimens we separate isolated andidentified the following Pseudomonas 111 strains including 16 different species: P. aeruginosa, 9; P. fluorescens biovars; 11; P. putida biovars, 14; P. syringae pathovars, 5; P. mendocina, 5; P. alcaligenes, 23; P. pseudoalcaligenes, 10; P. cepacia, 17; P. solanacearum, 1; P. testosteroni, 1; P. delafieldii, 3; P. facilis, 6; P. flava 1; P. psenudoflava, 2; P. palleronii, 1; and a new species of Pseudomonas--P. halosensibilis. The achievement of this study will provide scientific basis for working out the standards of food safety control and inspection, raising the level of food hygieneinspection, and directing the drinks menufacturers and selling units to strengthen the food safety control and inspection.

Identification of the antithrombin III heparin binding site

The heparin binding site of the anticoagulant protein antithrombin III (ATIII) has been defined at high resolution by alanine scanning mutagenesis of 17 basic residues previously thought to interact with the cofactor based on chemical modification experiments, analysis of naturally occurring dysfunctional antithrombins, and proximity to helix D. The baculovirus expression system employed for this study produces antithrombin which is highly similar to plasma ATIII in its inhibition of thrombin and factor Xa and which resembles the naturally occurring beta-ATIII isoform in its interactions with high affinity heparin and pentasaccharide (Ersdal-Badju, E., Lu, A., Peng, X., Picard, V., Zendehrouh, P., Turk, B., Björk, I., Olson, S. T., and Bock, S. C. (1995) Biochem. J. 310, 323-330). Relative heparin affinities of basic-to-Ala substitution mutants were determined by NaCl gradient elution from heparin columns. The data show that only a subset of the previously implicated basic residues are critical for binding to heparin. The key heparin binding residues, Lys-11, Arg-13, Arg-24, Arg-47, Lys-125, Arg-129, and Arg-145, line a 50-A long channel on the surface of ATIII. Comparisons of binding residue positions in the structure of P14-inserted ATIII and models of native antithrombin, derived from the structures of native ovalbumin and native antichymotrypsin, suggest that heparin may activate antithrombin by breaking salt bridges that stabilize its native conformation. Specifically, heparin release of intramolecular helix D-sheet B salt bridges may facilitate s123AhDEF movement and generation of an activated species that is conformationally primed for reactive loop uptake by central beta-sheet A and for inhibitory complex formation. In addition to providing a structural explanation for the conformational change observed upon heparin binding to antithrombin III, differences in the affinities of native, heparin-bound, complexed, and cleaved ATIII molecules for heparin can be explained based on the identified binding site and suggest why heparin functions catalytically and is released from antithrombin upon inhibitory complex formation.

Anemia and perinatal death result from loss of the murine ecotropic retrovirus receptor mCAT-1

The mCAT-1 gene encodes a basic amino acid transporter that also acts as the receptor for murine ecotropic leukemia viruses. Targeted mutagenesis in embryonic stem cells has been used to introduce a germ-line null mutation into this gene. This mutation removes a domain critical for virus binding and inactivates amino acid transport activity. Homozygous mutant pups generated from these cells were approximately 25% smaller than normal littermates, very anemic, and died on the day of birth. Peripheral blood from homozygotes contained 50% fewer red blood cells, reduced hemoglobin levels, and showed a pronounced normoblastosis. Histological analyses of bone marrow, spleen, and liver showed a decrease in both erythroid progenitors and mature red blood cells. Mutant fetal liver cells behaved normally in in vitro hematopoietic colony-forming assays but generated an anemia when transplanted into irradiated C.B.-17 SCID mice. Furthermore, reconstitution of the white cell compartment of SCID mice by mutant fetal liver cells was less complete than that observed with a mixed population of wild-type and heterozygous fetal liver cells. Primary embryo fibroblasts from mutant mice were completely resistant to ecotropic retrovirus infection. Thus, mCAT-1 not only appears to be the sole receptor for a group of murine ecotropic retroviruses associated with hematological disease but also plays a critical role in both hematopoiesis and growth control during mouse development.

Large-scale production of class I bound peptides: assigning a signature to HLA-B*1501

A peptide-based vaccine must be bound and presented by major histocompatibility complex class I molecules to elicit a CD8(+) T-cell response. Because class I HLA molecules are highly polymorphic, it has yet to be established how well a vaccine peptide that stimulates one individual's CD8(+) cytotoxic T lymphocytes will be presented by a second individual's different class I molecules. Therefore, to facilitate precise comparisons of class I peptide binding overlaps, we uniquely combined hollow-fiber bioreactors and mass spectrometry to assign precise peptide binding signatures to individual class I HLA molecules. In applying this strategy to HLA-B*1501, we isolated milligram quantities of B*1501-bound peptides and mapped them using mass spectrometry. Repeated analyses consistently assign the same peptide binding signature to B*1501; the degree of peptide binding overlap between any two class I molecules can thus be determined through comparison of their peptide signatures.

Biochemical evidence that patched is the Hedgehog receptor

The protein Sonic hedgehog (Shh) is essential for a variety of patterning events during development. It is the signal from the notochord that induces ventral cell fate in the neural tube and somites, and is the polarizing signal for patterning of the anterior-posterior axis of the developing limb bud. Because of these and other inductive functions of Shh, it is important to understand how the Hedgehog (Hh) signal is received by the target cells. Here we describe binding studies using labelled Shh that strongly suggest that the Hh receptor is encoded by patched (ptc), a gene first identified in genetic screens in Drosophila.

Candidacidal activity of human salivary histatin recombinant variants produced by site-directed mutagenesis

Histatin 5 (Hst5) is a 24-amino acid (aa) member of the Hst family that is found in human salivary secretions and exhibits candidacidal activity. Hst5 contains a 13-aa region that alone is capable of killing fungal pathogens and is referred to as the functional domain. To investigate the role of specific aa located within the functional domain, the pRSET bacterial expression system was used to produce recombinant Hst5 (re-Hst5) and several re-variants that were generated by site-directed mutagenesis. The vector pRSETC expresses genes of interest as fusion proteins attached to the carboxy end of an N-terminal His6 tag that binds to nickel (Ni2+). The re-variants were generated using the polymerase chain reaction (PCR) and had Gly substituted for either the His, Glu or Lys/Arg within the functional domain. PCR products that encoded either the wild-type or variant forms of re-Hst5 were inserted into pRSETC and produced as fusion proteins which were affinity purified from cell lysates by Ni(2+)-Sepharose chromatography. Fusion proteins were digested with CNBr and re-Hsts were purified by reversed-phase high performance liquid chromatography (RP-HPLC). Re-Hsts were tested in bioassays to measure the ability to kill both Candida albicans (C. albicans) blastoconidia and spheroplasts which were generated by removal of the cell wall. In both assays, re-Hst5 displayed dose-dependent candidacidal activity that was nearly identical to that of native Hst5 purified from human salivary secretions. Re-Hst5 variants with either Glu or Lys/Arg substitutions demonstrated significantly lower candidacidal activity in both assays, while the variant with His mutated showed essentially no activity at physiological concentrations. These results indicate that acidic and basic aa within the functional domain contribute to candidacidal activity and that the His are essential for candidacidal activity. Additionally, since C. albicans spheroplasts were also susceptible to Hsts, the cell wall is not an essential component in the Hst mechanism of candidacidal action.

Digestion responses to low oligosaccharide soybean meal by ileally-cannulated dogs

We investigated digestion responses to conventional and low oligosaccharide soybean meal (SBM) incorporation into diets for dogs. Five female dogs were fitted with T-type cannulas at the terminal ileum and fed five diets in a 5 x 5 Latin square design. Corn grain + poultry meal-based diets containing different levels and types of SBM (0% SBM, 18.55% conventional SBM, 18.55% low oligosaccharide SBM, 37.1% conventional SBM, 37.1% low oligosaccharide SBM) were formulated. Each period consisted of 11 d (7-d diet adaptation; 4-d collection of ileal digesta and feces). Intakes of DM, OM, CP, fat, and GE were not affected (P > .10) by treatment. Higher (P < .01) starch intakes and higher (P < .05) total dietary fiber (TDF) intakes were noted for dogs fed diets with SBM. Digestibilities of CP (P < .04) and starch (P < .002) at the ileum were higher for dogs fed the higher levels of SBM. Ileal digestibilities of most individual amino acids followed the CP response. Total tract digestibility of CP was higher (P < .006) in dogs fed the SBM diets. There were no significant differences in nutrient digestibilities between conventional and low oligosaccharide SBM. Stachyose and raffinose intakes by dogs were decreased dramatically (P < .001) as a result of substituting the low oligosaccharide SBM for conventional SBM at the higher dietary concentration, although sucrose intake by dogs fed low oligosaccharide SBM was higher (P < .001). Galactinol was present in low oligosaccharide SBM but not in conventional SBM. Total tract digestion of all oligosaccharides was near 100%. The low oligosaccharide SBM was digested as extensively, but no better than, conventional SBM.

Functional comparison of native and recombinant human salivary histatin 1

Histatin 1 is a histidine-rich phosphoprotein present in human parotid saliva that possesses candidacidal activity and functions in mineralization by adsorbing to hydroxyapatite. The objective of the present study was to develop a system for recombinant production of histatin 1 and to examine the role of phosphorylation in the functional activities of this molecule. Native histatin 1 (containing a phosphoserine at residue 2) was purified from parotid saliva, whereas a bacterial expression system was used to produce a recombinant form of histatin 1 (re-Hst1) that lacked phosphorylated serine. Histatin 1 cDNA was inserted into the vector pGEX-3X, which expresses foreign genes as soluble fusion proteins attached to the carboxyl-terminus of glutathione S-transferase (GST). The GST/re-Hst1 fusion protein was isolated from cell lysates by affinity chromatography on glutathione (GSH)-Sepharose and digested with cyanogen bromide to separate re-Hst1 from the GST fusion partner. The digest was subjected to reversed-phase high-performance liquid chromatography on a C18 column, and re-Hst1 was eluted as a well-defined peak. The yield of re-Hst1 was 4 mg/L of bacterial culture. Amino-terminal sequencing and amino acid analysis confirmed the final product as re-Hst1. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that native histatin 1 and re-Hst1 had the same apparent molecular weights, while cationic PAGE showed that re-Hst1 was more basic. Phosphate analysis indicated 1 mol phosphate/mol of native histatin 1, while re-Hst1 lacked any detectable phosphate. Re-Hst1 demonstrated candidacidal activity comparable to that of native histatin 1, but displayed substantially lower binding to hydroxyapatite. These results show that phosphorylation of histatin 1 at residue 2 contributes significantly to its ability to bind to hydroxyapatite.

Immunoglobulin depositions in peripheral nerves in polymyositis

An immunocytochemical study was performed in 6 peripheral nerve specimens from 6 cases of polymyositis. The results revealed that depositions of IgG, IgM, IgA and C3 were found in the epineurium, perineurium and the walls of capillaries. These findings demonstrated that depositions of immunoglobulins and the complement-mediated immunoreaction may play an important role in pathogenesis of polymyositis with peripheral nerve involvements.

Differences in the effect of acute ischemia on late potentials in susceptible and resistant dogs for sudden cardiac death

The low predictive value of the signal averaged ECG (SAECG) at rest may be due to the absence of any physiological perturbation. This study assessed changes of late potentials (LP) in the SAECG due to acute ischemia in five susceptible (S) and five resistant (R) dogs for sudden cardiac death. SAECGs were measured at rest prior to and during the last 3 min of 4 min transient occlusion of the left circumflex artery (CAO). At rest no significant differences were seen in the QRS duration (QRSD), the low amplitude signal duration (LAS40) and the root mean square voltage (RMS20) between S and R dogs. However, acute ischemia caused significant increases in QRSD and LAS40, but only in the S dogs. These results indicate differences in the ischemic modulation of the arrhythmogenic substrate in S and R group. Analysis of LP during acute ischemia may provide an important increase in the positive predictive value of the SAECG.

Recombinant histatins: functional domain duplication enhances candidacidal activity

Histatin 3 (Hst3) is a 32-amino-acid (aa) His-rich protein with antimicrobial activity found in human salivary secretions. To explore further the structure/function relationship of Hst, we utilized a bacterial system for the efficient production of recombinant Hst3 (re-Hst3) and Hst variants. Previously, we demonstrated that the middle portion of Hst3 (aa 13-24) contains the functional domain responsible for killing Candida albicans. Using PCR and splice overlap extension, a Hst variant (re-Hst3rep) was made in which the functional domain was repeated in tandem. Using the pRSET bacterial expression system, re-Hst3 and the variant re-Hst3rep were produced as chimeric fusions and were isolated from bacterial sonicates by affinity chromatography. Affinity purified fusion proteins were digested with CNBr and re-Hst were separated from their fusion partners by reverse-phase high-performance liquid chromatography. The activity of re-Hst3 and re-Hst3rep was compared to that of native Hst3 from human salivary secretions in the C. albicans killing assay. The LD50 values for candidacidal activity of native Hst3, re-Hst3 and re-Hst3rep were 7.2, 6.8 and 4.1 nmol/ml, respectively. At lower concentrations re-Hst3rep was five times more active than native Hst3 or re-Hst3 and at even lower concentrations re-Hst3rep exhibited significant candidacidal activity while native Hst3 and re-Hst3 were inactive. These results demonstrate an expression system for production of biologically active functional Hst and Hst variants and shows that repetition of the functional domain of Hst3 enhances candidacidal activity.

Oligonucleotide probes for mutans streptococci

Oligodeoxyribonucleotide probes complementary to hypervariable regions of the 16S ribosomal RNA were designed for specificity toward Streptococcus mutans and Streptococcus sobrinus. The probes were tested for specificity and sensitivity by hybridization with nucleic acid from over 100 mutans and non-mutans oral streptococci and other common oropharyngeal bacteria. Probes designated SM002 and SM010 were 100% sensitive and > 99% specific for S. mutans. Probe SSP001, designed to detect both S. mutans and S. sobrinus, was 88% sensitive and > 99% specific. The probes were able to detect nucleic acid extracted from 3 x 10(4)-1 x 10(5) homologous bacteria. Sensitivity did not vary significantly with the growth state of the cells, except for diminished signals when using nucleic acid extracted from very old cultures. The probes correctly identified 72 S. mutans colonies isolated from 10 volunteer saliva samples, using sugar utilization patterns as a reference standard. Ten isolates resembling S. mutans by colony morphology but not by sugar utilization patterns were correctly distinguished from mutans streptococci by the probes. These results demonstrate that oligonucleotide probes can accurately identify S. mutans in saliva samples.