Response of Bacterioplankton Communities to Cadmium Exposure in Coastal Water Microcosms with High Temporal Variability

Multiple anthropogenic disturbances to bacterial diversity have been investigated in coastal ecosystems, in which temporal variability in the bacterioplankton community has been considered a ubiquitous process. However, far less is known about the temporal dynamics of a bacterioplankton community responding to pollution disturbances such as toxic metals. We used coastal water microcosms perturbed with 0, 10, 100, and 1,000 μg liter⁻¹ of cadmium (Cd) for 2 weeks to investigate temporal variability, Cd-induced patterns, and their interaction in the coastal bacterioplankton community and to reveal whether the bacterial community structure would reflect the Cd gradient in a temporally varying system. Our results showed that the bacterioplankton community structure shifted along the Cd gradient consistently after a 4-day incubation, although it exhibited some resistance to Cd at low concentration (10 μg liter⁻¹). A process akin to an arms race between temporal variability and Cd exposure was observed, and the temporal variability overwhelmed Cd-induced patterns in the bacterial community. The temporal succession of the bacterial community was correlated with pH, dissolved oxygen, NO₃⁻-N, NO₂⁻-N, PO₄³⁻-P, dissolved organic carbon, and chlorophyll a, and each of these parameters contributed more to community variance than Cd did. However, elevated Cd levels did decrease the temporal turnover rate of community. Furthermore, key taxa, affiliated to the families Flavobacteriaceae, Rhodobacteraceae, Erythrobacteraceae, Piscirickettsiaceae, and Alteromonadaceae, showed a high frequency of being associated with Cd levels during 2 weeks. This study provides direct evidence that specific Cd-induced patterns in bacterioplankton communities exist in highly varying manipulated coastal systems. Future investigations on an ecosystem scale across longer temporal scales are needed to validate the observed pattern.     

Maternal Prenatal Positive Affect,Depressive and Anxiety Symptoms and Birth Outcomes: The PREDO Study

Background

We investigated whether maternal prenatal emotions are associated with gestational length and birth weight in the large PREDO Study with multiple measurement points of emotions during gestation.

Methods

Altogether 3376 pregnant women self-assessed their positive affect (PA, Positive and Negative Affect Schedule) and depressive (Center for Epidemiologic Studies Depression Scale, CES-D) and anxiety (Spielberger State Anxiety Scale, STAI) symptoms up to 14 times during gestation. Birth characteristics were derived from the National Birth Register and from medical records.

Results

One standard deviation (SD) unit higher PA during the third pregnancy trimester was associated with a 0.05 SD unit longer gestational length, whereas one SD unit higher CES-D and STAI scores during the third trimester were associated with 0.04–0.05 SD unit shorter gestational lengths (P-values ≤ 0.02), corresponding to only 0.1–0.2% of the variation in gestational length. Higher PA during the third trimester was associated with a significantly decreased risk for preterm (< 37 weeks) delivery (for each SD unit higher positive affect, odds ratio was 0.8-fold (P = 0.02). Mothers with preterm delivery showed a decline in PA and an increase in CES-D and STAI during eight weeks prior to delivery. Post-term birth (≥ 42 weeks), birth weight and fetal growth were not associated with maternal prenatal emotions.

Conclusions

This study with 14 measurements of maternal emotions during pregnancy show modest effects of prenatal emotions during the third pregnancy trimester, particularly in the weeks close to delivery, on gestational length. From the clinical perspective, the effects were negligible. No associations were detected between prenatal emotions and birth weight.     

Last Interglacial Hominid and Associated Vertebrate Fossil Trackways in Coastal Eolianites,South Africa

Two Late Pleistocene hominid footprint sites are known in South Africa, one on the west coast (Langebaan) and the other on the southeast coast (Nahoon). Both trackways occur in calcareous eolianites and are dated to the Last Interglacial (～120 ka). The chief objective is to infer anatomical features of these early anatomically modern hominid footprint makers, about which little is known. At Nahoon, trackways of at least five species of vertebrates, including three hominid footprints, are preserved as casts. One footprint preserves excellent detail, appearing in all respects to be modern, but possibly with a deformity of the small toe. The impressions are shallow and suggest slight build. The stature of the footprint maker, as estimated from foot length (19.2 cm), is ～127 cm, considerably less than modern adult Khoi-San and was probably made by a juvenile. The step length is short relative to foot length, a consequence of walking uphill on a yielding substrate. The Langebaan trackway (preserved as natural impressions) comprises two intact prints and remnants of a third. Pronounced push up mounds flank the prints and preservation of toe impressions is poor. The foot length is 22.8 cm, indicating a stature of ～1.57 m. This falls within the range of modern adult Khoi-San, lending some support to the notion that Middle Stone Age people were of small stature. The depth of the prints and clumsy progression are suggestive of heavy build.     

Dietary Exposure to Lead and Cadmium in Sweden

Abstract

A duplicate diet study on male and female pensioners in 1970–71 showed mean daily dietary lead intakes of 30 μg and 19 μg respectively. The corresponding cadmium intakes were 10.5μg and 12.9 μg. Analysis of duplicate diets collected during seven consecutive 24-hour periods from 15 women in Stockholm in 1988 showed a mean daily lead intake of 26 μg (range 13–40 μg). The corresponding cadmium intake was 8.5μg (range 5.7–14 μg). Analysis of faeces samples corresponding to the duplicate diets showed similar lead and cadmium contents (mean lead content 24 μg day^?1, range 10–41 μg day^?1; mean cadmium content 8.9 μg day^?1 range 5.5–12 μg day^?1). The median lead and cadmium concentrations in human milk collected in Uppsala were 2 μg kg^?1 and 0.1 mg kg^?1 respectively. The median weekly intakes of lead and cadmium by the breast-fed infants were calculated to be 2 μg kg^?1 body weight and 0.1 μg kg^?1 body weight. Analysis of seven daily diets, together representing the weekly diet of an adult Swedish male, showed a mean lead content of 26 μg (range 15–45 μg), and a mean cadmium content of 10 μg (range 7–15 μg). The mean daily intakes of lead and cadmium found by analysing market baskets prepared in 1987 were 17μg and 12μg respectively. Calculations based on food balance sheet data and levels of lead and cadmium in individual foods showed mean daily intakes of 30 μg lead and 14 μg cadmium per person.     

Dietary Exposure to Lead and Cadmium in Yugoslavia

Abstract

Lead exposure still represents a matter of health concern especially in Yugoslavia. To assess the exposure of normal urban population to lead and cadmium through food, a preliminary monitoring was performed on a small group of urban population. Lead, cadmium and some essential elements (calcium, zinc, iron, copper and manganese) were analysed in collected duplicate diet samples and compared to similar population in Sweden. We found that dietary exposure to lead and cadmium is similar to other countries although Yugoslav urban population is exposed to much higher concentrations of lead in air than in cities of developed countries, due to high lead in gasoline. However, daily intake of some essential elements was significantly lower.

Also populations living around lead smelters in various parts of Yugoslavia are still exposed to elevated environmental lead and cadmium levels. To assess the exposure of the population living in this area, a cumulative long-term exposure to lead was determined by measuring lead in deciduous teeth. Concentrations of lead and cadmium in vegetables, soil and meals from the same region were also analysed. Values obtained for lead and cadmium in food products grown in exposed and control area were found to be related to respective concentrations of these elements in soil as well as to the distance from the smelter. Meals prepared in this region show the same trend, revealing very high intake particularly of lead.

The influence of nutritional factors, i.e. dietary calcium on lead metabolism, was also studied. Blood lead concentration was determined in two groups of peasant women living in two regions with different dietary calcium intake. Lower blood lead values were found in the higher dietary calcium intake region.     

Soil Characteristics of Rehabilitating and Unmined Coastal Dunes at Richards Bay, KwaZulu-Natal, South Africa

The postmining rehabilitation of coastal sand dunes north of Richards Bay (28°43′S, 32°12′E), South Africa, is resulting in the development of a series of known-aged stands of vegetation dominated by Acacia karroo (sweet thorn). Other broad-leaved species are establishing themselves in rehabilitating areas more than 12 years of age. Soils from rehabilitating stands 3–5, 9–12, 13–15, and 16–18 years of age, from two disturbed, unmined stands 30 and 58 years of age, and from a mature unmined stand were examined to assess age-related trends in selected soil properties. Individually, these stands represent a series of different developmental stages of a coastal dune successional sere. Soil organic material, percentage organic carbon and concentrations of sodium, potassium, magnesium, calcium, and nitrogen increased with an increase in habitat regeneration age. Concentrations of most of these elements were lower than those recorded on the 58-year-old unmined and mature unmined stands. Multivariate analyses suggest, however, that the similarity of these values for rehabilitating stands to those for the unmined stands increased with an increase in regeneration age. The growth response of Raphanus sativus (radish) plants, based on mass attained under experimental growing conditions in soil collected from these stands, suggests an increase in soil fertility with an increase in regeneration age.     

An Evaluation of Habitat Rehabilitation on Coastal Dune Forests in Northern KwaZulu-Natal, South Africa

The rehabilitation program conducted by Richards Bay Minerals (RBM) of areas exposed to opencast surface mining of sand dunes north of Richards Bay (28°43'S, 32°12'E) on the coast of northern KwaZulu-Natal Province commenced 16 years before this study and has resulted in the development of a series of known-aged stands of vegetation. By assuming that these spatially separated stands develop along a similar pathway over time, instantaneous sampling should reveal successional or other changes usually associated with aging and should provide an opportunity to evaluate the success of rehabilitation. We compare relative densities of pioneer and secondary species, species richness, and a similarity index of the herbaceous layer, tree, beetle, millipede, bird, and small-mammal communities of rehabilitating areas of known age with those of 30-year-old unmined forests and unmined forests of unknown age adjacent to the rehabilitating area. Species richness for all but the mammalian taxa increased with increasing age of rehabilitating stands. For all taxa but the mammals and herbaceous layer, the unmined stands harbored more species than the mined rehabilitating stands. The relative densities of pioneer species of all the taxa decreased with an increase in the age of rehabilitating stands, whereas those of the secondary species increased with an increase in habitat age. Similarity between unmined stands and rehabilitating stands of different ages increased with increasing regeneration age of rehabilitating stands, suggesting that rehabilitating communities, in terms of species composition and relative densities, are developing towards the status of unmined communities. Rehabilitation based on RBM's management program of limited interference is occurring and may result in the reestablishment of a coastal dune forest ecosystem. But rehabilitation resulting from succession depends on the availability of species sources from which colonization can take place. In the Richards Bay mining operation the present mining path is laid out so that such refuges are present.     

Prenatal and Postnatal Exposure to Phthalate Esters and Asthma: A 9-Year Follow-Up Study of a Taiwanese Birth Cohort

Previous studies have shown that phthalate exposure in childhood is associated with the development of respiratory problems. However, few studies have assessed the relative impact of prenatal and postnatal exposure to phthalates on the development of asthma later in childhood. Therefore, we assessed the impact of prenatal and postnatal phthalate exposure on the development of asthma and wheezing using a Taiwanese birth cohort. A total of 430 pregnant women were recruited, and 171 (39.8%) of them had their children followed when they were aged 2, 5, and 8 years. The International Study of Asthma and Allergies in Childhood questionnaire was used to assess asthma and wheezing symptoms and serum total immunoglobulin E levels were measured at 8 years of age. Urine samples were obtained from 136 women during their third trimester of pregnancy, 99 children at 2 years of age, and 110 children at 5 years. Four common phthalate monoester metabolites in maternal and children’s urine were measured using liquid chromatography-electrospray ionization-tandem mass spectrometry. Maternal urinary mono-benzyl phthalate [MBzP] concentrations were associated with an increased occurrence of wheezing in boys at 8 years of age (odds ratio [OR] = 4.95 (95% CI 1.08–22.63)), for upper quintile compared to the others) after controlling for parental allergies and family members'' smoking status. Urinary mono-2-ethylhexyl phthalate [MEHP] levels over the quintile at 2-year-old were associated with increased asthma occurrence (adjusted OR = 6.14 (1.17–32.13)) in boys. Similarly, the sum of di-2-ethyl-hexyl phthalate [DEHP] metabolites at 5 years was associated with asthma in boys (adjusted OR = 4.36 (1.01–18.86)). Urinary MEHP in maternal and 5-year-old children urine were significantly associated with increased IgE in allergic children at 8 years. Prenatal and postnatal exposure to phthalate was associated with the occurrence of asthma in children, particularly for boys.     

Roads as Ecological Edges for Rehabilitating Coastal Dune Assemblages in Northern KwaZulu-Natal, South Africa

Abstract Post‐mining coastal dune rehabilitation north of Richards Bay, KwaZulu‐Natal started 20 years before field work for the present study commenced. This resulted in the development of a known age sere of coastal dune forest succession. These rehabilitating areas are fragmented by roads that may act as ecological edges. To establish whether roads affect regenerating bird, millipede, and rodent assemblages, multivariate techniques were applied to test for existence of edge and core assemblages within seral stages representative of the coastal dune forest successional sere. Edge and core assemblages were identified for both the bird and millipede communities but not for the rodent community. Low rodent numbers may have concealed edge effects, but the absence of edge and core assemblages could also be ascribed to the absence of a forest core. In the bird community species composition, richness, density, and total number of species contributed to the identification of edge and core assemblages. Within seral stages the species composition of millipedes differed between the edge and core assemblages. However, if the site was the same age the number of species in edge and core assemblages was similar. The generality of the edge concept should be approached with caution when dealing with taxa comprising species with such diverse natural histories as in the present study. It should also be kept in mind that some species require forest interiors for survival.     

Prenatal Endotoxemia and Placental Drug Transport in The Mouse: Placental Size-Specific Effects

Lipopolysaccharide (LPS) in high doses inhibits placental multidrug resistance P-glycoprotein (P-gp - Abcb1a/b) and breast cancer resistance protein (BCRP - Abcg2). This potentially impairs fetal protection against harmful factors in the maternal circulation. However, it is unknown whether LPS exposure, at doses that mimic sub-lethal clinical infection, alters placental multidrug resistance. We hypothesized that sub-lethal (fetal) LPS exposure reduces placental P-gp activity. Acute LPS (n = 19;150 µg/kg; ip) or vehicle (n = 19) were given to C57BL/6 mice at E15.5 and E17.5. Placentas and fetal-units were collected 4 and 24 h following injection. Chronic LPS (n = 6; 5 µg/kg/day; ip) or vehicle (n = 5) were administered from E11.5–15.5 and tissues were collected 4 h after final treatment. P-gp activity was assessed by [³H]digoxin accumulation. Placental Abcb1a/b, Abcg2, interleukin-6 (Il-6), Tnf-α, Il-10 and toll-like receptor-4 (Tlr-4) mRNA were measured by qPCR. Maternal plasma IL-6 was determined. At E15.5, maternal IL-6 was elevated 4 h after single (p<0.001) and chronic (p<0.05) LPS, but levels had returned to baseline by 24 h. Placental Il-6 mRNA was also increased after acute and chronic LPS treatments (p<0.05), whereas Abcb1a/b and Abcg2 mRNA were unaffected. However, fetal [³H]digoxin accumulation was increased (p<0.05) 4 h after acute LPS, and maternal [³H]digoxin myocardial accumulation was increased (p<0.05) in mice exposed to chronic LPS treatments. There was a negative correlation between fetal [³H]digoxin accumulation and placental size (p<0.0001). Acute and chronic sub-lethal LPS exposure resulted in a robust inflammatory response in the maternal systemic circulation and placenta. Acute infection decreased placental P-gp activity in a time- and gestational age-dependent manner. Chronic LPS decreased P-gp activity in the maternal myocardium and there was a trend for fetuses with smaller placentas to accumulate more P-gp substrate than their larger counterparts. Collectively, we demonstrate that acute sub-lethal LPS exposure during pregnancy impairs fetal protection against potentially harmful xenobiotics in the maternal circulation.     

Early Exposure to Respiratory Allergens by Placental Transfer and Breastfeeding

The relationship between allergen exposure and the onset of or protection from allergic diseases remains unclear. Many factors could be related to immunological responses, such as the age when the exposure occurs, type of allergen, timing, dose, and allergen route. In this study, we investigated whether exposure to respiratory allergens could occur in pregnancy or early life. In particular, we assessed whether Der p 1 and Blo t 5, as well as specific antibodies against these allergens, could be detected in 90 paired cord blood and colostrum samples. Der p 1 was detected in 58.6% of colostrum and 29% of cord blood samples, whereas Blot 5 was positive in 41.3% and 9.6% of the samples, respectively. Similar to specific IgA, which could be detected in all samples for both mites, specific IgG was found in a high number of colostrum samples, 93.5% and 94.8% for Dp and Bt, respectively. Although allergens were not detected in all cord blood samples, a high percentage of them (≥95%) were positive for specific IgM to both mites in cord blood samples, suggesting that neonates can be exposed and sensitized to airborne allergens during pregnancy. Many studies have attempted to correlate allergen exposure or its prevention in early infancy with the onset of or protection from allergic diseases. However, conflicting and inconsistent data do not show a clear correlation with or suggest a way to prevent allergen sensitization. Nevertheless, these unconvincing results could be better understood if the relationship with many aspects of allergen exposure after pregnancy could be clarified. Thus, it is necessary to address basic issues related to allergen exposure, including the development of reproducible, standardized and reliable methods, and to determine how and where the exposure occurs.     

Lead Exposure in Adult Males in Urban Transvaal Province,South Africa during the Apartheid Era

Human exposure to lead is a substantial public health hazard worldwide and is particularly problematic in the Republic of South Africa given the country’s late cessation of leaded petrol. Lead exposure is associated with a number of serious health issues and diseases including developmental and cognitive deficiency, hypertension and heart disease. Understanding the distribution of lifetime lead burden within a given population is critical for reducing exposure rates. Femoral bone from 101 deceased adult males living in urban Transvaal Province (now Gauteng Province), South Africa between 1960 and 1998 were analyzed for lead concentration by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Of the 72 black and 29 white individuals sampled, chronic lead exposure was apparent in nearly all individuals. White males showed significantly higher median bone lead concentration (ME = 10.04 µg·g⁻¹), than black males (ME = 3.80 µg·g⁻¹) despite higher socioeconomic status. Bone lead concentration covaries significantly, though weakly, with individual age. There was no significant temporal trend in bone lead concentration. These results indicate that long-term low to moderate lead exposure is the historical norm among South African males. Unexpectedly, this research indicates that white males in the sample population were more highly exposed to lead.     

Landscape fragmentation in South Coast Renosterveld,South Africa,in relation to rainfall and topography

The South Coast Renosterveld has been fragmented extensively by agriculture. The extent of this fragmentation in terms of overall habitat loss, fragment sizes and fragment numbers has not been described previously, thereby limiting the development of conservation strategies for this vegetation type. Patterns of renosterveld loss in three sectors along a west–east gradient were described using LANDSAT imagery and a Geographical Information System‐based program (FRAGSTATS) for spatial pattern analysis. These patterns were then correlated with rainfall and topography measures, which are indicators of agricultural potential. Over 80% of the South Coast Renosterveld has been cultivated. Fragmentation levels increased significantly from east to west, with 33% of natural vegetation remaining in the east and only 4% in the west. Topographical variables were the strongest predictors of patterns of renosterveld loss, with fragments being largely confined to slopes too steep for ploughing; they therefore face little risk of future cultivation. These results have implications for conservation planning options for the South Coast Renosterveld. There is the potential for large reserves in the east, as well as corridor reserves along major river valleys, but for only small, isolated reserves in the west.     

Coastal dune topography as a determinant of abiotic conditions and biological community restoration in northern KwaZulu-Natal,South Africa

Topography is rarely considered as an independent goal of restoration. However, topography determines microenvironmental conditions and hence living conditions for species. Restoring topography may therefore be an important first step in ecological restoration. We aimed at establishing the relative importance of topography where coastal dunes destroyed by mining are rebuilt as part of a rehabilitation program. We assessed the response of (1) microclimatic and soil conditions, and (2) woody plant and millipede species richness and density, to location-specific topographic profiles. We enumerated the topographic profile using variables of dune morphology (aspect, elevation, and gradient) as well as relative position on a dune (crest, slope, and valley). Temperature, relative humidity, and light intensity varied with aspect, elevation, gradient, and position. However, regeneration age was a better predictor of soil nutrient availability than these topographic variables. Age also interacted with topographic variables to explain tree canopy density and species richness, as well as millipede species richness. The density of keeled millipedes (forest specialists) was best explained by topographic variables alone. The transient nature of these new-growth coastal dune forests likely masks topography-related effects on communities because age-related succession (increasing structural complexity) drives the establishment and persistence of biological communities, not habitat conditions modulated by topography. However, our study has shown that the microhabitats associated with topographic variability influence specialist species more than generalists.     

Influence of Low-Level Prenatal Exposure to PCDD/Fs and PCBs on Empathizing,Systemizing and Autistic Traits: Results from the Duisburg Birth Cohort Study

Background

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are assumed to act as endocrine disruptor chemicals. Prenatal exposure to these pollutants might influence fetal steroid hormone levels, which are thought to be related to sex-typical development and autistic traits.

Objectives

We examined associations of prenatal levels of PCDD/Fs and PCBs with autism traits and sex-typical behaviour in childhood.

Methods

We measured levels of PCDD/Fs and PCBs in maternal blood samples during pregnancy using gas chromatography/high-resolution mass spectrometry. Sex-typical behaviour was assessed at 9 years of age (n = 96) and autistic traits at 10 years of age using the Social Responsiveness Scale (SRS; n = 100). Multiple regression analyses were conducted to estimate the associations between prenatal exposure and outcome variables.

Results

Blood concentrations (WHO₂₀₀₅-TEq) of ƩPCDD/Fs ranged from 2.93–46.45 pg/g _{lipid base} (median = 12.91 pg/g _{lipid base}) and concentrations of ƩPCBs were in the range of 1.24–25.47 pg/g _{lipid base} (median = 6.85 pg/g _{lipid base}) which is within the range of German background exposure. We found significant negative associations between PCDD/F levels in maternal blood and SRS scores in the whole group (β = -6.66, p < .05), in girls (β = -10.98, p < .05) and, in one SRS subscale, in boys (β = -6.86, p < .05). For PCB levels, associations with one SRS subscale were significant for the whole study group as were associations with two subscales in girls. We did not find significant associations between PCDD/F or PCB levels and sex-typical behaviour for either sex.

Conclusions

In an earlier part of this study, prenatal exposure to PCDD/Fs and PCBs was found to be associated with lower testosterone levels, therefore, our findings are consistent with the idea that autism spectrum conditions are related to fetal androgen levels. Several possible mechanisms, through which PCDD/Fs and PCBs might influence autistic behaviour, are discussed.     

European Origin of Bradyrhizobium Populations Infecting Lupins and Serradella in Soils of Western Australia and South Africa

We applied a multilocus phylogenetic approach to elucidate the origin of serradella and lupin Bradyrhizobium strains that persist in soils of Western Australia and South Africa. The selected strains belonged to different randomly amplified polymorphic DNA (RAPD)-PCR clusters that were distinct from RAPD clusters of applied inoculant strains. Phylogenetic analyses were performed with nodulation genes (nodA, nodZ, nolL, noeI), housekeeping genes (dnaK, recA, glnII, atpD), and 16S-23S rRNA intergenic transcribed spacer sequences. Housekeeping gene phylogenies revealed that all serradella and Lupinus cosentinii isolates from Western Australia and three of five South African narrow-leaf lupin strains were intermingled with the strains of Bradyrhizobium canariense, forming a well supported branch on each of the trees. All nodA gene sequences of the lupin and serradella bradyrhizobia formed a single branch, referred to as clade II, together with the sequences of other lupin and serradella strains. Similar patterns were detected in nodZ and nolL trees. In contrast, nodA sequences of the strains isolated from native Australian legumes formed either a new branch called clade IV or belonged to clade I or III, whereas their nonsymbiotic genes grouped outside the B. canariense branch. These data suggest that the lupin and serradella strains, including the strains from uncultivated L.cosentinii plants, are descendants of strains that most likely were brought from Europe accidentally with lupin and serradella seeds. The observed dominance of B. canariense strains may be related to this species' adaptation to acid soils common in Western Australia and South Africa and, presumably, to their intrinsic ability to compete for nodulation of lupins and serradella.