Adaptation to soil pollution by cadmium excretion in natural populations of Orchesella cincta (L.) (Collembola)

Population differentiation in Orchesella cincta (L.) (Collembola) populations, from various heavy metal contaminated sites, was studied by comparing cadmium excretion efficiency in first generation (F₁) laboratory individuals. Animals from sites with high metal concentrations in the litter and with a long history of contamination showed significantly higher excretion efficiencies than animals from low pollution, or reference sites. Differences found in the F₁ laboratory animals suggest evidence for genetic differences between the populations.Beneficial and detrimental effects of cadmium excretion were studied in relation to body growth and cadmium concentrations. In chronically exposed animals from an unpolluted site, no physiological acclimation was observed. Excretion efficiency was negatively correlated with body concentrations of cadmium. No detrimental effects were found.Whole-body equilibrium concentrations of cadmium and lead were similar in F₁ animals from the reference site and polluted sites. Significant differences in excretion efficiencies imply that the distribution of toxic metals over body compartments differs, tolerant populations having a higher proportion deposited in the gut. Body concentrations of zinc were consistently higher in animals from the polluted site, during both cadmium and zinc exposure. No detrimental effects of increased cadmium excretion on body concentrations of zinc were observed. Population comparisons of cadmium excretion efficiency data and growth reduction in F₁ laboratory animals showed that both parameters were inversely related. Cadmium and lead contamination were not the sole factors determining tolerance differentiation.     

Genetic and demographic responses of mercury-exposed mosquitofish (Gambusia holbrooki) populations: temporal stability and reproductive components of fitness

Two previous mesocosm studies showed changes in glucosephosphate isomerase-2 (Gpi-2) allele frequencies in mosquitofish populations exposed to mercury for 111 d or two years. A previous selection component analysis of single-generation populations exposed for 111 d to 18 microg/L Hg suggested that female sexual selection and fecundity selection could contribute to changes in Gpi-2 allele frequencies. The present multigeneration study was conducted to determine the stability of Gpi-2 allele frequencies over four years of mercury exposure, measure the reproductive fitness of Gpi-2 genotypes inhabiting control and mercury-contaminated mesocosms to determine a mechanism explaining changes in Gpi-2 allele frequencies, investigate differences in the demographic characteristics of mercury-exposed and control populations, and investigate the water quality of the mesocosms to determine if variables other than mercury show concordant patterns among mesocosms. Differences in Gpi-2 allele frequencies between control and mercury-exposed populations were stable over four years (approximately eight generations) of mercury exposure. Mercury-exposed female mosquitofish had a lower probability of being gravid than control females (p = 0.001). Mercury-exposed females also had lower fecundity (total number of eggs and embryos) than control females (p = 0.036). Unlike the results of the more intense mercury exposures in the single generation study, no strong evidence was found that Gpi-2 genotype influenced fecundity or the probability of being gravid in both control and mercury-exposed females. The quantification of fitness components is difficult but has the potential to enhance our understanding of how toxicants alter allele frequencies in exposed populations.     

Genetic polymorphism of MTHFR G1793A in Chinese populations

5,10-methylenetetrahydrofolate reductase (MTHFR) is an important enzyme in folate metabolism. A novel polymorphic site in MTHFR (G1793A) could influence the homocysteine levels and was first described in 2002. Investigations revealed that this allele was associated with susceptibility to several cancers, but its distribution around the world was not adequate. To study the prevalence of the mutant frequency in Chinese populations, 923 healthy individuals from 13 Chinese populations distributing widely from north to south were collected. DNA samples were isolated from peripheral blood samples and genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), with the digestion of restriction endonuclease BsrBI. Of the 923 individuals, 82.1% were GG homozygous, 17.2% were GA heterozygous and 0.7% were AA homozygous. The frequency of the MTHFR 1793A allele in all tested individuals was 9.3%, which was slightly lower than indicated by HapMap (10%, Beiing Han, 45 samples). The frequencies of A allele were generally higher in southern China than that in northern China, and the frequencies had significant variance in 13 Chinese populations (X² = 26.315, P = 0.010). Summarizing of the MTHFR G1793A allele polymorphism, including control groups in the case–control studies, we found only 20 normal peoples with AA homozygous (7 Chineses, 1 Caucasian, 2 Java Indonesias, 2 non-Hispanic whites, 6 Irish women, 2 Indians). The Java Indonesias and Ashkenzai Jevish had the highest (26.6%) and the lowest (1.3%) 1793A frequency, respectively. Together with our previous data, the MTHFR G1793A polymorphism was in linkage disequilibrium with both C677T and A1298C polymorphism sites in Chinese population, but not as strong as presented by HapMap.     

The relative sensitivity of competing hydropsychid species to fluoride toxicity in the Cache la Poudre River (Colorado)

The influence of increased fluoride concentrations generated by a wastewater treatment plant on the spatial distribution and abundance of benthic larvae of Hydropsychidae (Insecta, Trichoptera) species in the Cache la Poudre River (Colorado) was examined. Acute lethal concentrations of fluoride ion (F^–) to these species were determined in soft water (average value of hardness 40.2 mg CaCO₃/L) by static toxicity bioassays. The wastewater treatment plant caused a significant (P<0.05) increase in the fluoride concentration at three downstream sampling sites (mean values 1.17, 0.84, and 0.56 mg F^–/L at 0.1, 1.6, and 9.2 km downstream sites, respectively) compared with the upstream reference station (0.31 mg F^–/L). The 48, 72, 96, 120, and 144-h LC50s (mg F^–/L) were 52.6, 25.8, 17.0, 13.4, and 11.5 for Hydropsyche bronta Ross, 102.0, 53.5, 34.7, 27.0, and 21.4 for Hydropsyche occidentalis Banks, and 128.0, 73.2, 42.5, 31.9, and 24.2 for Cheumatopsyche pettiti (Banks). LC50 values for H. bronta were significantly (P<0.05) lower than LC50 values for the other two test species. Abundance and biomass of all hydropsychid species were significantly (P<0.05) lower at the 0.1 km downstream site than at the upstream reference site. H. occidentalis was usually the most abundant species at the reference and 9.2 km downstream stations, with highest abundances at the 9.2 km downstream site. C. pettiti was dominant at 0.1 and 1.6 km downstream sites, showing higher abundances at the 1.6 km downstream site than at the upstream reference site. H. bronta was never collected at 0.1 and 1.6 km downstream sites, but was abundant at the upstream reference site. It is concluded that the fluoride pollution is not a major factor in determining the spatial distribution and abundance of competing hydropsychid species in the Cache la Poudre River. However, the greater sensitivity of H. bronta larvae to fluoride ions could result in decreased abundances of this species at downstream sampling sites.     

Fluoride Toxicity and Bioaccumulation in the Invasive Amphipod Dikerogammarus villosus (Sowinsky, 1894): a Laboratory Study

The tolerance of the invasive amphipod Dikerogammarus villosus to fluoride (F⁻) toxicity was examined via laboratory experiments. 96-h LC₅₀ and 240-h NOEC values were estimated to be 5.8 and 0.95 mg F⁻/L, respectively. Average whole-body fluoride content in control amphipods was 27.6 μg F⁻/g dry weight, whereas in exposed amphipods it ranged from 3,637 to 16,994 μg F⁻/g dry weight. All these results indicate that D. villosus is a very sensitive species to fluoride toxicity. Overall it is concluded that the potential risk of invasion for D. villosus in either natural or polluted freshwater ecosystems, exhibiting relatively high fluoride levels (at least ten-fold higher than the average freshwater background level of 0.15 mg F⁻/L), must be low.     

Influence of polymorphisms for apolipoprotein B (ins/del,Xbal, EcoRI)and apolipoprotein E on serum lipids and apolipoproteins in a Javanese population

A total of 231 healthy subjects from a central Javanese population were investigated for the distribution of three apolipoprotein B (apo B) polymorphisms (ins/del, XbaI, and EcoRI), as well as apolipoprotein E (apo E) polymorphism in relation to serum lipid and apolipoprotein concentrations. The frequencies of the rarer alleles (del, 0.09; X⁺, 0.1; and R^?, 0.06) were lower than have been found for some Asian and European populations. Distribution of genotypes was in Hardy-Weinburg equilibrium for all the polymorphisms. A linkage disequilibrium was observed only between the ins/del and XbaI site polymorphisms of apo B (χ₄² = 25.3; P < 0.001) consistent with that observed in some other population studies. No polymorphism of the apo B gene had an association with serum lipid or apolipoprotein concentrations in this population except for XabI, which appeared to be associated with serum TG (as the log transform: R² = 8.3; F = 4.8; P < 0.01). The apo E4 allele was found to be associated with significantly higher serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDLC). Apo E polymorphism explained 5.9% of the sample variance of serum LDLC (F = 5.4; P < 0.01). © 1994 Wiley-Liss, Inc.     

Effect of Pollution History on Immunological Responses and Organ Histology in the Marine Mussel Mytilus edulis Exposed to Cadmium

The effect of previous toxicant exposure (i.e., exposure history) on an organism’s response to re-exposure to the toxicant is of considerable interest. The marine mussel Mytilus edulis was collected from reference and polluted sites in southwest England, and groups of mussels from each site were exposed to 20 μg/L CdCl₂ for 0, 1, 4, and 8 days and compared with unexposed controls. End points evaluated were tissue metal and electrolyte concentrations, haemolymph chemistry, haemocyte characteristics [counts, neutral red uptake (NRU), and phagocytosis], histology, and expression of metallothionein gene (mt10) expression in digestive glands. Field-collected animals differed by collection site for some end points at time zero, at which time tissue Fe and Pb concentrations were greater and NRU and condition index lower in mussels from the polluted site. Subsequent exposure to cadmium (Cd) in the laboratory caused Cd accumulation mainly in digestive gland, but there were no site-specific effects on tissue trace-metal concentrations. NRU, phagocytosis, and haemolymph Na⁺ and K⁺ concentrations differed among sites and Cd treatment, but there were no clear trends. Exposure to Cd resulted in lower Ca²⁺ concentrations in gill, digestive gland, and haemolymph in animals from the polluted site compared with controls (Kruskal–Wallis, p ≤ 0.05). Lesions, including necrosis, inflammation, and neoplasia, were observed in animals from the polluted site, but the frequency of these lesions appeared to decrease unexpectedly after Cd exposure. Expression of mt10 increased 3-fold in Cd-exposed animals from the polluted site compared with all other groups (Kruskal–Wallis, p = 0.01). We conclude that Cd exposure affected some immune responses in M. edulis, but pre-exposure history influenced toxicological outcomes of Cd exposure in the laboratory.     

Classification of Groundwater Contamination in Yuxi River Valley,Shaanxi Province,China

This study investigated groundwater contamination in the Yuxi River Valley in northern Shaanxi Province, one of largest energy resource centers in China. Groundwater samples collected from 129 locations in the Yuxi River Valley area were analyzed and evaluated to establish the local groundwater quality zonings. Results indicate that groundwater in the Yuxi River Valley is contaminated, and the dominant contaminants in the groundwater are ammonium (NH₄ ⁺) and nitrite (NO₂ ⁻). Maximal concentration of NH₄ ⁺ was detected at 0.019 and 3.50 mg/L in the samples collected up-gradient and down-gradient, respectively, of the segment of Yuxi River that flows through Yulin City. Concentration of NO₂ ⁻ was detected at 0.0015 and 1.522 mg/L, respectively from the same samples. Zones I through IV, from non-polluted to seriously polluted, were identified for groundwater quality in the Yuxi River Valley. We attribute the groundwater contamination in the Yuxi River valley to sources in the Yulin township, presumably its wastewater discharge.     

Variability of CYP2C8 Polymorphisms in Three Jordanian Populations: Circassians,Chechens and Jordanian-Arabs

CYP2C8 is a member of Cytochrome P450 enzymes system. It plays an important role in metabolizing a wide range of exogenous and endogenous compounds. CYP2C8 is involved in the metabolism of more than 100 drugs, typical substrates include: anticancer agents, antidiabetic agents, antimalarial agents, lipid lowering drugs and many others that constitute 20% of clinically prescribed drugs. Genetic variations of CYP2C8 have been reported with different frequencies in different populations. These genetic polymorphisms can lead to differences in the efficacy and safety of different types of medications metabolized by CYP2C8. The aim of this study was to investigate the allele frequencies of CYP2C8*3 (rs10509681 and rs11572080) and CYP2C8*4 (rs1058930) polymorphisms in three populations living in Jordan; Circassians and Chechens and Jordanian-Arabs and compare those frequencies with other populations. A total of 200 healthy Jordanians, 93 Circassians and 88 Chechens were included in this study. Genotyping of CYP2C8*3 and CYP2C8*4 polymorphisms was done by using polymerase chain reaction (PCR) followed by Restriction Fragment Length Polymorphism (RFLP). Using the Chi-square test, we found that the prevalence of CYP2C8*3 and *4 among the three populations were significantly different. Moreover, the mutant allele CYP2C8*3 (416A) was only detected in the Jordanian-Arab population with an allele frequency of 0.082, while the mutant allele CYP2C8*4 (792G) was detected with frequencies of 0.065, 0.122, 0.017 in Jordanian-Arabs, Circassians and Chechens, respectively. As our results show, CYP2C8*3 was undetectable in our Circassians and Chechens samples, on the other hand, Circassians had the highest allele frequency of CYP2C8*4 compared to Chechens and Jordanian-Arabs. These genetic variations of the gene encoding the CYP2C8 drug metabolizing enzymes can lead to clinical differences in drug metabolism and ultimately variations in drug effectiveness and toxicities. This study provides evidence for the importance of personalized medicine in these populations and can be the foundation for future clinical studies.

     

The cerebellar GABAAR α6-R100Q polymorphism alters ligand binding in outbred Sprague–Dawley rats in a similar manner as in selectively bred AT and ANT rats

The alcohol-tolerant AT and alcohol-nontolerant ANT rat lines have been selectively bred for innate sensitivity to ethanol-induced motor impairment. The cerebellar GABA_A receptor (GABA_AR) α6 subunit alleles α6-100R and α6-100Q are segregated in the AT and ANT rats, respectively. This α6 polymorphism might explain various differences in pharmacological properties and density of GABA_ARs between the rat lines. In the present study, we have used nonselected outbred Sprague–Dawley rats homozygous for the α6-100RR (RR) and α6-100QQ (QQ) genotypes to show that these RR and QQ rats display similar differences between genotypes as AT and ANT rat lines. The genotypes differed in their affinity for [³H]Ro 15-4513 and classic benzodiazepines (BZs) to cerebellar “diazepam-insensitive” (DZ-IS) binding sites, in density of cerebellar [³H]muscimol binding and in the antagonizing effect of furosemide on GABA-induced inhibition of [³H]EBOB binding. The results suggest the involvement of α6-R100Q polymorphism in these line differences and in the differences previously found between AT and ANT rats. In addition, the α6-R100Q polymorphism induces striking differences in [³H]Ro 15-4513 binding kinetics to recombinant α6β3γ2s receptors and cerebellar DZ-IS sites. Association of [³H]Ro 15-4513 binding was ∼10-fold faster and dissociation was ∼3–4-fold faster in DZ-IS α6βγ2 receptors containing the α6-100Q allele, with a resulting change of ∼2.5-fold in equilibrium dissociation constant (K_D). The results indicate that in addition to the central role of the homologous α6-100R/Q (α1-101H) residue in BZ binding and efficacy, this critical BZ binding site residue has a major impact on BZ binding kinetics.     

Copper Binding by Dissolved Organic Matter in Freshwaters in Kenya

The binding of Cu2+ to dissolved organic matter in eight different natural water samples obtained from different locations in Kenya was studied by potentiometric titration method. The DOC contents of the eight natural water samples ranged from 2.71 to 374 mg/L. The water samples were adjusted to a uniform background electrolyte concentration of 0.5 M NaNO₃ and pH 6 and the temperature maintained at 20°C during the assay. A Nernst equation E (mV) = −32.175 pCu + 305.5 (R ²=0.9996) obtained for the Cu2+ calibration standards (10^–4–10^–6 M) was used to determine the concentration of free and bound Cu2+, respectively. The bound [Cu2+] varied by a factor of 2, ranging from 2.67 × 10⁻³ mol/kg DOC (in a high DOC alkaline lake water sample) to 3.2962 × 10⁻¹ mol/kg (in a low DOC river water sample). The binding constants (Log K) varied by a factor of 2 and ranged from 3.43 to 5.57. The percentage binding ranged from 87% to almost 100% in the eight natural water samples. A Suwannee River Fulvic Acid standard sample (40 mg/L DOC) was used for comparison and for validation of the method.     

Effect of the induction of transgenerational obesity on maternal-fetal parameters

Maternal obesity can cause complications for both women and their offspring for generations. Therefore, we intended to verify the repercussions of induction of transgenerational obesity on biochemical parameters, reproductive performance, and congenital anomaly frequency in Wistar rats. Female rats were used from successive generations. The female rats of parental generation (F₀, n=10) were mated to obtain their offspring (F₁ generation). F₁ female rats received a monosodium glutamate (MSG) solution to induce obesity (n=07) or vehicle (control, n=06) during the neonatal period. These adult female rats were classified as normal or obese using the Lee Index, mated, and delivered offspring (F₂ generation), which were also evaluated for obesity using the Lee Index in adult life (F₂MSG, n=13, born from obese dams) or non-obesity status (F₂Control, n=12, born from control dams), and were mated in adulthood. During pregnancy, glycemia and an oral glucose tolerance test (OGTT) were analyzed. At term pregnancy, the females were sacrificed for serum biochemical profile, maternal reproductive outcomes, and fetal development. In F₂MSG rats, body weight gain at early pregnancy, glycemia by OGTT, total cholesterol, high-density-lipoprotein, and alanine transaminase activity were higher compared with those of F₂Control rats. F₂MSG rats also presented a lower implantation number and gravid uterus weight, increased pre-implantation loss and anomaly frequency in their fetuses (F₃ generation) compared with those of F₂Control rats. Therefore, even without significant changes in body weight gain, obesity was established at the end of pregnancy of Wistar rats using other biomarkers. Additionally, these rats showed multiple adverse reproductive outcomes, confirming the deleterious effects that lead to obesity.     

Effect of antioxidant vitamin supplementation on DNA damage and repair in human lymphoblastoid cells

In this study the possible protective effects of ascorbic acid and α‐tocopherol (singly and in combination) on Raji lymphoblastoid cells exposed to various doses of X‐rays or hydrogen peroxide (H₂O₂) are investigated. DNA strand breaks and alkali‐labile sites were measured using the alkaline comet assay. Survival and hypoxanthine gua‐nine phosphoribosyl transferase mutant frequency were measured using the colony‐forming assay. Ascorbic acid (60 μM) and α‐tocopherol (30 μM) were added singly or together to cell culture medium 24 hours before treatment and were present during treatment. After the 24‐hour supplementation period with ascorbic acid alone, α‐tocopherol alone, and ascorbic acid + α‐tocopherol, the level of endogenous DNA damage was significantly lower (p < 0.05) than in the nonsupplemented culture, as assessed by the comet assay. By use of the comet assay, it was observed that ascorbic acid exhibited an overall protective effect against DNA damage induced after X‐ray treatment, whereas α‐tocopherol exhibited an overall protective effect against DNA damage induced after H₂O₂ treatment. Significant increases were observed in the percent survival after 1‐Gy X‐rays and 5 and 20 μM H₂O₂ in those cultures supplemented with ascorbic acid alone and α‐tocopherol alone relative to the nonsupplemented cultures. The endogenous level of mutant frequency was also significantly decreased in the presence of ascorbic acid relative to the nonsupplemented culture. These findings are consistent with the concept that ascorbic acid and α‐tocopherol can, under certain conditions, protect against oxidatively induced DNA damage.     

Using estimates of metal bioavailability in the soil and genetic variation of allozymes to investigate heavy metal tolerance in the earthworm Eisenia fetida (Oligochaeta)

In a recent study, we showed that the earthworm species Eisenia fetida, inhabiting an extremely high metal polluted compost heap on a wine farm, did not have elevated body loads of the metals but exhibited genotoxic tolerance when exposed to Cd in the laboratory (Voua Otomo and Reinecke, 2010). To unravel the mechanism behind the surprisingly low metal body burdens on one hand and genotoxic tolerance on the other hand, we investigated the estimated bioavailability of these metals (Cu, Zn, Pb and Cd) using sequential extraction methods with CaCl₂ and di-ethylene-triamine-pentaacetic acid (DTPA) and allozyme polymorphism in this field population, a laboratory control as well as a long-term Cd exposed population. The amounts of mobile (extracted with CaCl₂) and mobilizable (extracted with DTPA) metals in relation to the total (extracted with nitric acid) metals were all below 0.05% for all four metals, suggesting low availability for uptake. The low availability of these metals could not be explained by physico-chemical properties of soil but by the phenomenon of aging of the metals. There was no difference in allozyme frequency between metal tolerant and non-metal tolerant populations of E. fetida. This suggested that the tolerance found in earlier studies could be a mere physiological adaptation     

Extent and distribution of linkage disequilibrium in the Old Order Amish

Knowledge of the extent and distribution of linkage disequilibrium (LD) is critical to the design and interpretation of gene mapping studies. Because the demographic history of each population varies and is often not accurately known, it is necessary to empirically evaluate LD on a population‐specific basis. Here we present the first genome‐wide survey of LD in the Old Order Amish (OOA) of Lancaster County Pennsylvania, a closed population derived from a modest number of founders. Specifically, we present a comparison of LD between OOA individuals and US Utah participants in the International HapMap project (abbreviated CEU) using a high‐density single nucleotide polymorphism (SNP) map. Overall, the allele (and haplotype) frequency distributions and LD profiles were remarkably similar between these two populations. For example, the median absolute allele frequency difference for autosomal SNPs was 0.05, with an inter‐quartile range of 0.02–0.09, and for autosomal SNPs 10–20 kb apart with common alleles (minor allele frequency≥0.05), the LD measure r² was at least 0.8 for 15 and 14% of SNP pairs in the OOA and CEU, respectively. Moreover, tag SNPs selected from the HapMap CEU sample captured a substantial portion of the common variation in the OOA (～88%) at r²≥0.8. These results suggest that the OOA and CEU may share similar LD profiles for other common but untyped SNPs. Thus, in the context of the common variant‐common disease hypothesis, genetic variants discovered in gene mapping studies in the OOA may generalize to other populations. Genet. Epidemiol. 34: 146–150, 2010. © 2009 Wiley‐Liss, Inc.     

Research on flux of dry atmospheric falling dust and its characterization in a subtropical city,Guangzhou, South China

Guangzhou is the central city in the Pearl River Delta (PRD), China, and is one of the most polluted cities in the world. To characterize the ambient falling dust pollution, two typical sampling sites: urban (Wushan) and suburban (University Town) areas in Guangzhou city were chosen for falling dust collection over 1 year at time intervals of 1 or 2 months. The flux of dry deposition was calculated. In addition, mineral composition and morphology of atmospheric falling dust were studied by X-ray diffraction, scanning electron microscopy, and microscopic observation. The results revealed that the dust flux in Guangzhou city was 3.34–3.78 g/(m² month) during the study period. The main minerals in the dust were quartz, illite, calcite, kaolinite, gypsum, plagioclase, dolomite, and amorphous matter. The morphological types included grained and flaky individual minerals, chain-like aggregates, spherical flying beads, and irregular aggregates, with the chain-like and spherical aggregates indicators of industrial ash. The major dusts were derived from industrial and construction activities. The gypsum present in the dust collected in winter season was not only derived from cement dust but may also have originated from the reaction of calcic material with sulfuric acids resulting from photooxidation of SO _x and NO _x , which confirmed serious air pollution due to SO _x and NO _x in Guangzhou. The abatement of fossil fuel combustion emissions and construction dust will have a significant beneficial effect on dust reduction.     

Estimation of phytochemicals and antioxidant activity of underutilized fruits of Andaman Islands (India)

The present study aimed to determine the antioxidant activity and phytochemical contents in 10 underutilized fruits of Andaman Islands (India) namely Malpighia glabra L., Mangifera andamanica L., Morinda citrifolia L., Syzygium aqueum (Burm.f) Alst., Annona squamosa L., Averrhoa carambola L., Averrhoa bilimbi L., Dillenia indica L., Annona muricata L. and Ficus racemosa L. The antioxidant activity varied from 74.27% to 98.77%, and the methanol extract of M. glabra showed the highest antioxidant activity (98.77%; inhibitory concentration, IC₅₀ = 262.46 μg/ml). Methanol was found to be a better solvent than acetone and aqueous for estimating the antioxidant activity. M. glabra was found to be rich in phytochemicals viz. polyphenol (355.74 mg/100 g), anthocyanin (91.31 mg/100 g), carotenoids (109.16 mg/100 g), tannin (24.39 mg/100 g) and ascorbic acid (394.23 mg/100 g). Carbohydrate content was estimated to be highest in M. glabra (548 mg/100 g). Phenols, tannins, anthocyanins and carotenoids contents showed positive correlation (r² = 0.846, r² = 0.864, r² = 0.915 and r² = 0.806, respectively) with antioxidant activity. The information generated in present study will be useful for bioprospecting of underutilized fruits of Andaman Islands.     

Fusicoccin Counteracts the Toxic Effect of Cadmium on the Growth of Maize Coleoptile Segments

The effects of cadmium (Cd; 0.1–1000 μM) and fusicoccin (FC) on growth, Cd²⁺ content, and membrane potential (E _m) in maize coleoptile segments were studied. In addition, the E _m changes and accumulation of Cd and calcium (Ca) in coleoptile segments treated with Cd²⁺ combined with 1 μM FC or 30 mM tetraethylammonium (TEA) chloride (K⁺-channel blocker) were also determined. In this study, the effects of Ca²⁺-channel blockers [lanthanum (La) and verapamil (Ver)] on growth and content of Cd²⁺ and Ca²⁺ in coleoptile segments were also investigated. It was found that Cd at high concentrations (100 and 1000 μM) significantly inhibited endogenous growth of coleoptile segments and simultaneously measured proton extrusion. FC combined with Cd²⁺ counteracted the toxic effect of Cd²⁺ on endogenous growth and significantly decreased Cd²⁺ content (not the case for Cd²⁺ at the highest concentration) in coleoptile segments. Addition of Cd to the control medium caused depolarization of E _m, the extent of which was dependent on Cd concentration and time of treatment with Cd²⁺. Hyperpolarization of E _m induced by FC was suppressed in the presence of Cd²⁺ at 1000 μM but not Cd²⁺ at 100 μM. It was also found that treatment of maize coleoptile segments with 30 mM TEA chloride caused hyperpolarization of E _m and decreased Cd²⁺ content in coleoptile segments, suggesting that, in the same way as for FC, accumulation of Cd²⁺ was dependent on plasma membrane (PM) hyperpolarization. Similar to FC, TEA chloride also decreased Ca²⁺ content in coleoptile segments. La and Ver combined with Cd²⁺ (100 μM) significantly decreased Cd content in maize coleoptile segments, but only La completely abolished the toxic effect of Cd²⁺ on endogenous growth and growth in the presence of FC. Taken together, these results suggest that the mechanism by which FC counteracts the toxic effect of Cd²⁺ (except at 1000 μM Cd²⁺) on the growth of maize coleoptile segments involves both stimulation of PM H⁺-ATPase activity by FC as well as Cd²⁺-permeable, voltage-dependent Ca channels, which are blocked by FC and TEA chloride-induced PM hyperpolarization.     

Cytochrome P4501A Induction and Porphyrin Accumulation in PLHC-1 Fish Cells Exposed to Sediment and Oil Shale Extracts

The present study describes the use of a fish hepatoma cell line (PLHC-1) in monitoring the biological effects of sediments collected from recipient waters of the oil shale industry. Sampling sites were located in River Purtse and River Kohtla in northeast Estonia. The effects of pure oil shale on the PLHC-1 cells were also studied. The cells were exposed to n-hexane–extracted samples in 48-well plates for 24 h, and 7-ethoxyresorufin O-deethylase (EROD) activity, total protein, and porphyrin content were measured in the exposed cells. Polycyclic aromatic hydrocarbon (PAH) contents in the samples were measured by high-performance liquid chromatography (HPLC). All the sediment and oil shale samples induced CYP1A activity and led to porphyrin accumulation in the cells. The most potent inducers were the sediments collected near the oil shale processing plants (site Lüganuse in River Purtse and Kohtla in River Kohtla), as well as those at the most downstream site in River Purtse (Purtse). These samples possessed high total PAH contents, ranging from 4,270 to nearly 150,000 μg/kg dry sediment. The presence of other lipophilic organic contaminants in the samples was not determined in this study. Both EROD activity and porphyrin content exhibited biphasic induction curves, and the ED₅₀ ¹ values for EROD activity were lower than the ED₅₀s for porphyrin content. 2,3,7,8-Tetrachlorodibenzo-p-dioxin induction equivalents (TCDD-EQs) calculated from EROD induction potencies correlated well with total PAHs (r ² = 0.827 and p = 0.003 for log-transformed data) and also with individual PAHs. TCDD-EQs for porphyrin content did not correlate significantly with total PAHs (log-log r² = 0.785, p = 0.116). The biological potency and PAH contamination of the samples showed the same rank order, except at Lüganuse, where sediment extracts induced CYP1A and porphyrins more than could have been expected based on PAH contents. Bioassay-derived induction EQs (normalized to dibenz(a,h)anthracene) were 20- to 3,200-fold greater than EQs calculated from the concentrations of five PAHs, suggesting important contributions from other compounds or nonadditive effects. The PLHC-1 cells proved to be a sensitive bioanalytical tool for sediments contaminated with PAH-type pollutants in the oil shale processing area. We suggest further use of this bioassay in screening and monitoring waters with similar background of pollution as in northeast Estonia. Received: 24 August 1998/Accepted: 22 July 1999     

SP-A1, SP-A2 and SP-D gene polymorphisms in severe acute respiratory syncytial infection in Chilean infants

Respiratory syncytial virus (RSV) is the principal pathogen that causes acute lower respiratory tract infection (ALRI) in infants. Severe RSV-ALRI has been associated with the host genetic susceptibility. To assess whether severe RSV disease in infants is associated with certain single nucleotide polymorphism (SNP) into the gene of SP-A1, SP-A2 and SP-D, a prospective study was performed among blood donors and RSV-infected infants aged < or = 6 months, considering their severity, according to a strict scoring system. Allele and genotype frequencies were compared using χ²-test. Association studies and haplotype analysis were tested by using Armitagës trend test and Unphased 3.0 program.A total of 118 RSV-infected infants and 104 blood donors were enrolled into the study; 59 infants had a severe respiratory disease, 34 children developed a moderate illness and 25 had a mild disease. There was no difference in the allelic and genotypic frequencies of SP-A1, but intragenic haplotypes showed significant differences among infected infants and blood donors (p = 0.0021). 1A⁰ variant of SP-A2 was the most frequent allele in all groups. Thr₁₁ allele of SP-D is significantly higher in RSV infants (p = 0.028), as given by its higher frequency in severe disease (p = 0.046). Heterozygous Thr₁₁/Met₁₁ was significantly more common in infected infants (p = 0.037), because it has higher frequency in critically ill children (p = 0.017). Thr₁₆₀ allele was significantly higher in severe infants compared with blood donors (p = 0.046) and infants with mild disease (p = 0.018). Thr₁₁-Thr₁₆₀-Ser₂₇₀ haplotype was significantly more common in RSV-infants, due to severe (p = 0.00000034) and moderate disease (p = 0.000009). Differences were also found among severe and mild disease (p = 0.026). Differences found with other authors, indicate the need for local studies to identify genetic biomarkers of severity.