An epidemiological study of reproductive function biomarkers in male welders

In a cross-sectional study, the serum concentrations of inhibin B and prolactin of 96 male current welders were compared with the concentrations measured in 96 age-matched referents. Also, 23 patients who were all former welders diagnosed as having welding-related manganism were studied. The current welders' geometric mean (GM) airborne exposure to manganese (Mn) was 121 µg m^-3 (range 7-2320). The serum concentrations of prolactin adjusted for age and smoking habits (GM 193 mIU l^-1 vs. 166 mIU l^-1; p=0.047) and inhibin B adjusted for alcohol consumption (arithmetic mean (AM) 151 ng l^-1 vs. 123 ng l^-1; p=0.001) were higher in the welders compared with the referents. The whole blood Mn concentration was associated with the serum prolactin concentrations. Tobacco smoking resulted in lower serum prolactin concentrations. The GM serum prolactin concentrations of the patients did not significantly differ from that of the referents, but their AM serum inhibin B concentration was statistically significantly lower. The results may suggest an effect of Mn on the pituitary that is reversible upon cessation of exposure. Lower inhibin B concentrations in the patients could point to a functional impairment of the testicular Sertoli cells, that may be caused by a welding fume component or other factors in their work environment.     

Biomarkers of iron status and trace elements in welders

Iron status was studied in 137 welders exposed to a geometric mean (GM) air concentration of 214 μg/m³ (range 1–3230) of manganese (Mn), in 137 referents and in 34 former welders. The GM concentrations of S-ferritin were 119 (3–1498), 112 (9–1277) and 98 (12–989) μg/L (p = 0.24) in the three groups, respectively. Also the GM concentrations of S-hepcidin were not significantly different between the groups (8.4 μg/L (2.8–117); 6.6 μg/L (1.8–100); 6.5 μg/L (1.2–22)) (p = 0.22). Multiple linear regression analysis including all welders and referents showed an increase in the concentration of S-ferritin associated with having serum carbohydrate deficient transferrin (S-CDT) above the upper reference limit of ≥1.7%, indicating high alcohol consumption. Serum C-reactive protein was not associated with exposure as welders, but an association with S-ferritin was shown. The GM S-ferritin concentrations among all welders and referents with S-CDT ≥ 1.7% were 157 μg/L (95% CI 113–218) as compared to 104 μg/L (95% CI 94–116) (p = 0.02) in those with S-CDT < 1.7%. The GM concentrations of Mn in biological fluids were higher in the welders as compared to the referents, while S-Fe, S-Co and B-Co were statistically significantly lower. This could suggest a competitive inhibition from Mn on the uptake of Fe and Co. Increasing concentrations of S-CDT was associated with higher S-Mn, S-Fe and B-Co in the multiple linear regression analysis. The association between S-CDT and S-Fe remained when all subjects with high S-CDT (≥1.7%) were excluded, suggesting increased uptake of Fe even at lower alcohol consumption.     

Increased synthesis of α‐tocopherol,paramylon and tyrosine by Euglena gracilis under conditions of high biomass production

Aims: To analyse the production of different metabolites by dark‐grown Euglena gracilis under conditions found to render high cell growth. Methods and Results: The combination of glutamate (5 g l^?1), malate (2 g l^?1) and ethanol (10 ml l^?1) (GM + EtOH); glutamate (7·15 g l^?1) and ethanol (10 ml l^?1); or malate (8·16 g l^?1), glucose (10·6 g l^?1) and NH₄Cl (1·8 g l^?1) as carbon and nitrogen sources, promoted an increase of 5·6, 3·7 and 2·6‐fold, respectively, in biomass concentration in comparison with glutamate and malate (GM). In turn, the production of α‐tocopherol after 120 h identified by LC‐MS was 3·7 ± 0·2, 2·4 ± 0·1 and 2 ± 0·1 mg [g dry weight (DW)]^?1, respectively, while in the control medium (GM) it was 0·72 ± 0·1 mg (g DW)^?1. For paramylon synthesis, the addition of EtOH or glucose induced a higher production. Amino acids were assayed by RP‐HPLC; Tyr a tocopherol precursor and Ala an amino acid with antioxidant activity were the amino acids synthesized at higher concentration. Conclusions: Dark‐grown E. gracilis Z is a suitable source for the generation of the biotechnologically relevant metabolites tyrosine, α‐tocopherol and paramylon. Significance and Impact of the Study: By combining different carbon and nitrogen sources and inducing a tolerable stress to the cell by adding ethanol, it was possible to increase the production of biomass, paramylon, α‐tocopherol and some amino acids. The concentrations of α‐tocopherol achieved in this study are higher than others reported previously for Euglena, plant and algal systems. This work helps to understand the effect of different carbon sources on the synthesis of bio‐molecules by E. gracilis and can be used as a basis for future works to improve the production of different metabolites of biotechnological importance by this organism.     

Impact of 900 MHz electromagnetic field exposure on main male reproductive hormone levels: a Rattus norvegicus model

This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague–Dawley rats (180?±?10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group (p?p?p?相似文献   

Bioremediation of metal contamination in the Plankenburg River,Western Cape,South Africa

Three bioreactors (two laboratory-scale and one on-site) were evaluated for their efficiency to reduce metal concentrations in water collected from the Plankenburg River, South Africa. Water (bioreactors one, two and on-site) and bioballs (bioreactors two and on-site) collected throughout the study periods were digested and analysed using Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). Aluminium (Al), nickel (Ni), and zinc (Zn) concentrations decreased from 0.41 mg l^?1 to 0.06 mg l^?1 (85%), 0.2 mg l^?1 to 0.07 mg l^?1 (65%) and 75 mg l^?1 to 0.02 mg l^?1 (97%), respectively (bioreactor one). Aluminium [(1.55–0.38 mg l^?1 (75%)], copper (Cu) [57% (from 0.33 mg l^?1 to 0.14 mg l^?1)], iron (Fe) [71.99–40.4 mg l^?1 (44%)] and manganese (Mn) [57% (0.07–0.03 mg l^?1)] concentrations also decreased in the water samples from bioreactor two. In the on-site, six-tank bioreactor system, concentrations for Fe, Cu, Mn and Ni decreased, while Zn and Al concentrations increased. The concentrations recorded in biofilm samples were higher than the corresponding water samples. The bioballs employed in the bioreactor were thus shown to be efficient attachment surfaces for biofilm development and subsequent metal accumulation. Potentially metal-tolerant organisms (Pseudomonas sp., Sphingomonas sp., and Bacillus sp.) were also identified using phylogeny.     

Effect of biotic and abiotic elicitors on production of betulin and betulinic acid in the hairy root culture of Betula pendula Roth

Abstract

Betulin (B) and betulinic acid (BA) are two triterpenoids with a wide range of biological and medicinal activities in different organs of Betula pendula. This research aimed to increase the accumulation of B and BA in the hairy root culture of B. pendula by seven biotic and abiotic elicitors. Hairy root was induced in the stem’s inner bark of B. pendula using the C58C1 strain in the WPM (Woody Plant Medium). The effects of different concentrations of elicitors and different time of root harvest in hairy root culture of B. pendula showed that highest level of growth index (GI), B, and BA was acquired in treated hairy roots with chitosan (CTS), chlorocholine chloride (CCC) and chitosan nano-fiber (CTS NF). Highest GI of B. pendula hairy roots was 13 that was obtained in the roots treated with CTS 150?mg l^?1 on the 8th day. The highest content of BA was 1.3?mg g^?1 DW after treatment with 1?mg l^?1CCC on the 4th and 6th days and 200?mg l^?1CTS NF on the 10th day. The highest B content (0.94?mg g^?1DW) was obtained in the treated hairy root by 2?mg l^?1 CCC after 4 and 6?days.     

Degradation of dye-containing textile effluent by the agaric white-rot fungus Clitocybula dusenii

Raw mixed-dye wastewater from a textile dye-producing plant was partly decolorized by the agaric white-rot fungus, Clitocybula dusenii. The fungus had higher Mn peroxidase (MnP) and laccase activities when grown with dye effluent than in control cultures. The activity of MnP increased commensurately with the proportion of the raw dye wastewater in the medium (control: 20 U l^–1; 10% v/v effluent: 67 U l^–1; 25% v/v effluent: 130 U l^–1; and 33% v/v effluent: 180 U l^–1). Maximal decolorization rates were achieved over 20 d at 28 °C using four-fold diluted dye-containing effluent on a 5 d pre-grown mycelium.     

Arthrospira platensis biomass with high protein content cultivated in continuous process using urea as nitrogen source

Aims: Arthrospira platensis has been studied for single‐cell protein production because of its biomass composition and its ability of growing in alternative media. This work evaluated the effects of different dilution rates (D) and urea concentrations (N₀) on A. platensis continuous culture, in terms of growth, kinetic parameters, biomass composition and nitrogen removal. Methods and results: Arthrospira platensis was continuously cultivated in a glass‐made vertical column photobioreactor agitated with Rushton turbines. There were used different dilution rates (0·04–0·44 day^?1) and urea concentrations (0·5 and 5 mmol l^?1). With N₀ = 5 mmol l^?1, the maximum steady‐state biomass concentration was1415 mg l^?1, achieved with D = 0·04 day^?1, but the highest protein content (71·9%) was obtained by applying D = 0·12 day^?1, attaining a protein productivity of 106·41 mg l^?1 day^?1. Nitrogen removal reached 99% on steady‐state conditions. Conclusions: The best results were achieved by applying N₀ = 5 mmol l^?1; however, urea led to inhibitory conditions at D ≥ 0·16 day^?1, inducing the system wash‐out. The agitation afforded satisfactory mixture and did not harm the trichomes structure. Significance and Impact of the Study: These results can enhance the basis for the continuous removal of nitrogenous wastewater pollutants using cyanobacteria, with an easily assembled photobioreactor.     

The effect of nutrients and environmental conditions on biomass and oil production in Botryococcus braunii Race B strains

The green alga Botryococcus braunii is widely recognized as a source of non-fossil oil. However, limitations in Botryococcus biomass production hamper its commercial exploitation. This study examines the effects of nutrients (nitrogen and iron) and environmental conditions (temperature, light intensity and photoperiod) on biomass and oil production in two B. braunii Race B strains, Kossou-4 and Overjuyo-3. The highest biomass and oil production were obtained at a nitrogen concentration of 750 mg l^?1, iron concentration of 6 mg l^?1, at 25°C and at 135 µmol photons m^?2 s^?1 with a photoperiod of 16 h light:8 h darkness. Culturing the strains in Blue-green (BG11) medium containing optimized nutrients under optimal conditions resulted in an up to ~10.6-fold increase in biomass. In Kossou-4 and Overjuyo-3 strains, biomass increased from 1.647 g 10 l^?1 and 3.137 g 10 l^?1 respectively in normal BG11 medium to 17.390 g 10 l^?1 and 21.721 g 10 l^?1 in optimized BG11 media and growth conditions. This was accompanied by ~8–10.5-fold increase in oil production compared with that in normal BG11 medium. Oil (0.324 g 10 l^?1 and 0.211 g 10 l^?1) was produced in normal BG11 medium in Kossou-4 and Overjuyo-3 strains respectively, compared with 2.642 g 10 l^?1 (Kossou-4) and 2.206 g 10 l^?1 (Overjuyo-3) in modified BG11 media under optimized conditions. Therefore, optimization of nutrients and environmental conditions can increase biomass and oil production in the two strains of B. braunii.     

Serum Clara cell protein (CC16) in healthy young smokers

The CC16 microprotein is the main secretory product of Clara cells, which are epithelial cells lining lung airways. In crossing through the bronchoalveolar/blood barrier, CC16 diffuses passively into plasma. Serum CC16 (sCC16) has recently been proposed as a biomarker for detecting Clara cell impairments. The aim of this study was to assess if sCC16 concentrations are reduced in a group of healthy young smokers. A group of 118 healthy young males volunteered to take part in the study. Each subject answered a questionnaire, and provided blood and urine samples. Serum CC16, urinary cotinine and creatinine were measured. Median serum CC16 concentrations were lower in smokers than in non-smokers (11.3 mug l^-1 vs 14.6 mug l^-1; p = 0.005; N = 89 and 29, respectively) but did not correlate with either the daily or the life-time cigarette consumption, or with urinary cotinine concentrations. sCC16 did not correlate with age or body mass index in the whole study population or in the groups of smokers and non-smokers. These results suggest the reduction in sCC16 concentrations in a group of healthy young smokers may be an early effect of cigarette smoking.     

SIMULTANEOUS ASSIMILATION OF AMMONIUM AND NITRATE BY GELIDIUM NUDIFRONS (GELIDIALES: RHODOPHYTA)1

Simultaneous assimilation of NH₄ and NO₃ by Gelidium nudifrons Gardner was observed in culture experiments of 4 possible combinations of NH₄ and NO₃. The combinations tested were those in which the concentration of both N sources were in the range of 3.0–4.0 μg-atN · l^?1; both in the range of 0.5–1.0 μg-atN · l^?1; one in the 3.0–4.0 μg-atN · l^?1 range and the other in the 0.5–1.0 μg-atN · l^?1 range; and, visa versa. The data suggest that the pools of both NH₄ and NO₃ are simultaneously available for algal assimilation.     

Influence of biofilms on iron and manganese deposition in drinking water distribution systems

Although health risk due to discoloured water is minimal, such water continues to be the source of one of the major complaints received by most water utilities in Australia. Elevated levels of iron (Fe) and/or manganese (Mn) in bulk water are associated with discoloured water incidents. The accumulation of these two elements in distribution systems is believed to be one of the main causes for such elevated levels. An investigation into the contribution of pipe wall biofilms towards Fe and Mn deposition, and discoloured water events is reported in this study. Eight laboratory-scale reactors were operated to test four different conditions in duplicate. Four reactors were exposed to low Fe (0.05?mg?l^?1) and Mn (0.02?mg?l^?1) concentrations and the remaining four were exposed to a higher (0.3 and 0.4?mg?l^?1 for Fe and Mn, respectively) concentration. Two of the four reactors which received low and high Fe and Mn concentrations were chlorinated (3.0?mg?l^?1 of chlorine). The biological activity (measured in terms of ATP) on the glass rings in these reactors was very low (～1.5 ng cm^?2 ring). Higher concentrations of Fe and Mn in bulk water and active biofilms resulted in increased deposition of Fe and Mn on the glass rings. Moreover, with an increase in biological activity, an increase in Fe and Mn deposition was observed. The observations in the laboratory-scale experiments were in line with the results of field observations that were carried out using biofilm monitors. The field data additionally demonstrated the effect of seasons, where increased biofilm activities observed on pipe wall biofilms during late summer and early autumn were found to be associated with increased deposition of Fe and Mn. In contrast, during the cooler months, biofilm activities were a magnitude lower and the deposited metal concentrations were also significantly less (ie a drop of 68% for Fe and 86% for Mn). Based on the laboratory-scale investigations, detachment of pipe wall biofilms due to cell death or flow dynamics could release the entrapped Fe and Mn into the bulk water, which could lead to a discoloured water event. Hence, managing biofilm growth on drinking water pipelines should be considered by water utilities to minimize accumulation of Fe and Mn in distribution networks.     

Endospore dipicolinic acid detection during Bacillus thuringiensis culture

Aims: The aim of this work was to detect Bacillus thuringiensis endospore production during fermentation under conditions hindering endospore detection, i.e. in a complex undefined industrial medium with a high content of solids in suspension. Methods and Results: Bacterial endospore production was measured using the photoluminescence of dipicolinate (DPA) with Tb³⁺. The high temperature and pressure of a conventional autoclave was used to release DPA from the endospores. The endospore was obtained from B. thuringiensis var. kurstaki HD‐73 fermentations in industrial‐type media with 25·1 and 54·1 g l^?1 glucose, 4·4 and 35·3 g l^?1 soybean meal, 5·8 g l^?1 yeast extract, 9·2 g l^?1 corn steep solids and mineral salts. Conclusions: In this study, we successfully determined the DPA concentrations during the culture of B. thuringiensis in high‐concentration soybean meal media. A good correlation was found between microscope endospore counting and DPA measurements in the cultures. Significance and Impact of the Study: Because of synergy between Cry protein and endospore in B. thuringiensis bioinsecticides formulation, it is important to be able to determine endospore development during B. thuringiensis industrial‐type fermentation, in order to ascertain the beginning of sporulation.     

Tolerance and Immobilization of Cobalt by Some Bacteria from Ferromanganese Crusts of the Afanasiy Nikitin Seamounts

Bacteria isolated from cobalt–enriched ferromanganese crusts on the Afanasiy Nikitin Seamounts in the Equatorial Indian Ocean were examined for their ability to tolerate, and immobilize cobalt in unamended seawater and seawater amended with 0.01% glucose. Retrievable bacterial counts in the form of CFU (colony forming units) on media supplemented with 1 mmol Co l^?1 (58 mg Co l^?1) and 1 mmol Mn l^?1 (54 mg Mn l^?1) were in the range of 1.71 × 10⁴ to 1.05 × 10⁵ gm^?1 (wet wt) of crust, respectively. Most of the isolates (14/24) were pigmented and showed taxonomic affinities to Flavobacterium sp. Two representative isolates were tested for their tolerance of cobalt. We observed that in amended medium, the isolates tolerated up to 1 mmol Co l^?1, whereas in unamended medium they tolerated upto 10 mmol Co l^?1. Microscopic observations of cultures incubated with 10 mmol Co l^?1 showed the occurrence of an extracellular slime layer, which may be responsible for immobilizing the cobalt from the liquid phase. In the unamended medium, the tolerance and stimulation in total cell counts was similar to that in amended medium or sometimes greater. Total cell counts peaked at 100 μmol Co l^?1 for incubations in unamended medium (1.1–2.5 × 10¹¹ cells l^?1) and at 0.1–1 μmol Co l^?1 for incubations in amended medium (1.5–2.6 × 10¹¹ cells l^?1). Counts of formazan-stained respiring cells of both the isolates in the unamended medium reached up to a maximum of 2.9–7.8 × 10¹⁰ l^?1 after incubation for 10 days at 23(±1)°. In the amended medium cell counts of respiring cells attained a maximum in the range of 4.6–15.8 × 10¹⁰ l^?1 at 100 μmol Co l^?1. The Co immobilization rate was on average 82 (± 87.9, n = 24) μmol of Co d^?1. Since the isolates were naturally occurring bacteria from crusts, they could be more environmentally acceptable and safe if used for metal recovery and bio-leaching.     

The relationships between gonad development and sex steroid levels at different ages in Acipenser schrenckii

The histological developments of the gonad and the associated sex steroid levels were determined in the breeding stocks of Acipenser schrenckii (age classes 1 to 5) maintained under natural temperature regimes (December 4°C; August 26°C). Early sex differentiation was observed in 1‐year‐old fish, while testosterone (T) and 17β‐estradiol (E₂) levels ranged from T 1.1 to 3.4 nmol l^?1 (average 1.8 nmol l^?1), and E₂ varied from 24 to 85 pmol l^?1 (av. 50.3 pmol l^?1). Gonadal status of 2‐year‐old males was in stage II while ovaries were at stage I, exhibiting T levels from 1.2 to 4.4 nmol l^?1 (av. 2.2 nmol l^?1), and E₂ concentrations from 10 to 97 pmol l^?1 (av. 38.9 pmol l^?1). At the age of 3 years, the testes in males were at developmental stage III while the ovaries remained in stage I, with T levels ranging from 1.3 to 21.7 nmol l^?1 (av. 9.6 nmol l^?1), and E₂ concentrations ranging from 17 to 108 pmol l^?1 (av. 44.8 pmol l^?1). At the age of 4 years, testes in males were at developmental stage III while ovaries in females had reached stage II, with T concentrations ranging from 7.3 to 52.6 nmol l^?1 (av. 26.3 nmol l^?1), and E₂ levels between 13 and 86 pmol l^?1 (average 55.3 pmmol l^?1). In 5‐year‐old fish, the testes reached maturity stage while the ovaries were mostly in stage III, with T values from 5.7 to 44.2 nmol l^?1 (av. 13.9 nmol l^?1), and E₂ concentrations from 21 to 453 pmol l^?1 (av. 137.7 pmol l^?1). Data demonstrated large differences in sex steroid levels among immature Amur sturgeon, and testicular maturation occurred earlier than ovarian maturation.     

Heavy metal concentrations in,and human health risk assessment of,three commercially valuable fish species in the lower Niger River,Nigeria

The concentrations of Fe, Mn, Ni, Pb and V in water, sediment and the gill, liver and muscle tissues of Synodontis resupinatus, Heterotis niloticus and Clarias gariepinus, all commercially important fish species of the lower Niger River, were investigated in 2015. Water, sediment and fish samples were collected for six months and heavy metals were determined using an Atomic Absorption Spectrometer. Fe ranked highest in water and sediment, with concentrations of 2.74 mg l^?1 and 61.60 mg kg^?1, respectively. Metals followed the magnitude of Fe > Mn > Ni > V > Pb in the water and Fe > Mn > V > Ni > Pb in the sediments. Metal concentrations were higher in the tissues of S. resupinatus compared with H. niloticus and C. gariepinus. Fe was also highest in the gills, liver and muscle of the three fish species. Its highest concentration of 132.97 mg kg^?1 dry weight was recorded in the gills of S. resupinatus. Bioconcentration factors of metals ranged from 8.79 for Mn in H. niloticus muscle to 67.99 for Ni in S. resupinatus gills. The fish species studied pose no health risk for all metals studied, because the target hazard quotient was less than 1 and the estimated daily intakes of the metals were below the reference doses.     

Urinary excretion of 1-hydroxypyrene as a biomarker of exposure to polycyclic aromatic hydrocarbons from different sources

1-Hydroxypyrene (1-OHP) urinary excretion has been studied in subjects exposed to polycyclic aromatic hydrocarbons (PAH) from different sources (urban air pollution, cigarette smoking, food contamination or occupational exposure). In Study A, statistically significant differences among subjects categorized according to daily cigarette consumption were observed: 1-OHP median excretion of heavy smokers (more than 20 cigarettes per day; 1-OHP=371 ng l^-1; n=6) was significantly increased over that of non-smokers (1-OHP=160 ng l^-1; n=79), light smokers (less than 10 cigarettes per day,1-OHP=157 ng l^-1; n=7) and also medium smokers (10-20 cigarettes per day, 1-OHP=154 ng l^-1; n=13) (p&lt;0.04). In smokers, 1-OHP excretion (y, ng l^-1) increased with the intensity of cigarette consumption and was associated with self-reported number of cigarettes smoked daily (x, n) (y=20+16.6x; r=0.58, n=22, p&lt;0.01), urinary thiocyanate (x, µmoll^-1) (y=55+2.6x; r=0.57, n=20, p&lt;0.01) and cotinine (x, µg l^-1) (y=89+0.23x; r=0.62, n=17, p&lt;0.01). In Study B the influence of smoked food consumption on 1-OHP excretion was evaluated: 1-OHP excretion began to increase as soon as 3 h after a PAH-rich meal and peak values were reached between 6 and 9 h after lunch. Maximum excretion mean values were respectively 525 ng l^-1 for non-smokers (n=8) and 650 ng l^-1 for smokers (n= 4). 1-OHP concentrations in next-morning samples were back to pre-lunch levels both for non-smokers and smokers. In Study C non-smoker workers (n=28) occupationally exposed to PAH in a steel plant were investigated. At values of airborne pyrene ranging between 6 and 30 µg m^-3, excretion values of 1-OHP up to 80000 ng l^-1 were observed. The use of urinary 1-OHP as a screening test to discriminate between smokers and non-smokers in the presence of uncorrected dietary influence has been calculated according to a cut-off value of 461 ng l^-1 (reference group upper limit): the 1-OHP positive predictive value is 57%, its predictive negative value is 77%, sensitivity is 15% and specificity is 96%. In conclusion, 1-OHP appears to be a valuable biomarker of pyrene exposure. It will be nevertheless more accurate in assessing human PAH exposure from multiple sources if the influence of different kinetics for inhaled (particulate or gaseous) or ingested PAH are considered and if the role of oxidative polymorphism is adequately elucidated. The possibility of using 1-OHP to estimate the total burden of PAH from different sources or of screening groups with different PAH exposure appears to be a possible approach. However, the use of 1-OHP to evaluate the associated risk of cancer is still a premature target.     

Inhibitory effect of obesity on gonadotropin, estradiol, and inhibin B levels in fertile women

Objective: To examine whether obesity and insulin resistance have an independent effect on the gonadotropin, estradiol, and inhibin B serum levels and follicle count in the early follicular phase of fertile women with a wide range of BMI and without signs of hyperandrogenism. Research Methods and Procedures: Twenty‐two overweight and obese (BMI ≥25.0 kg/m²) women and 10 normal‐weight (BMI <25.0 kg/m²) women, all having apparently normal fertility, were studied. Serum concentrations of follicle‐stimulating hormone (FSH), luteinizing hormone (LH), estradiol, inhibin B, and insulin, level of insulin resistance (estimated by homeostasis model assessment for insulin resistance), and follicle count were measured during the early follicular phase (Days 2 to 5 of the menstrual cycle). Results: Overweight women showed lower FSH (p < 0.001), LH (p < 0.001), and inhibin B (p < 0.05) levels compared with normal‐weight women, whereas estradiol concentrations and follicle count were not significantly different between the two groups. When normal‐weight and overweight women were examined as a group and multiple regression analyses were performed, estradiol showed a negative association with BMI (or waist circumference) (p < 0.05) and a positive correlation with LH (p < 0.05) and FSH (p < 0.05); inhibin B maintained a positive association only with estradiol (p < 0.05); and FSH and LH showed a negative correlation with BMI (or waist circumference) (p < 0.001 and p < 0.01, respectively). Discussion: Overweight and obese fertile women have lower FSH, LH, inhibin B, and estradiol levels in the early follicular phase, with a possible direct inhibitory effect of body mass on gonadotropin and estradiol production, independently of age, insulin (concentrations and sensitivity), and other hormones. By contrast, the number of ovary follicles does not seem to be influenced by insulin and body mass in these patients.     

Comparison of media formulations used to selectively cultivate Dekkera/Brettanomyces

Aims: The objectives of this research were to (i) optimize the concentration of cycloheximide for use in WL media used in the wine industry and (ii) evaluate Dekkera/Brettanomyces differential medium (DBDM) as a means to detect Dekkera. Methods and Results: Dekkera bruxellensis and other yeasts were transferred into WL broths containing 0, 10, 50 or 100 mg l^?1 of cycloheximide. While several grew in 10 mg l^?1, only Hanseniaspora uvarum, Pichia guillermondii, Schizosaccharomyces pombe and D. bruxellensis tolerated ≥50 mg l^?1 of the antibiotic. On solidified WL media after 8‐days incubation, colony sizes of two strains of D. bruxellensis (B1b and ATCC 52905) decreased with increased concentrations of cycloheximide, while others (F3 and P2) were unaffected. Although D. bruxellensis B1b did not grow well on another selective medium, DBDM, colony development was improved by the addition of sterilized red wine. Conclusions: Of the concentrations tested, 50 mg l^?1 cycloheximide inhibited many grape/wine yeasts yet generally yielded countable colonies of Dekkera (1–2·5 mm diameter). Several strains of Dekkera did not grow well on DBDM, probably due to the lack of an unidentified nutrient(s). Significance and Impact of the Study: Better media formulations will improve the detection of Dekkera, thereby increasing microbiological control during winemaking.     

Winter limnology: a comparison of physical,chemical and biological characteristics in two temperate lakes during ice cover

The winter dynamics of several chemical, physical, and biological variables of a shallow, polymictic lake (Opinicon) are compared to those of a deep, nearby dimictic lake (Upper Rock) during ice cover (January to early April) in 1990 and 1991. Both lakes were weakly inversely thermally stratified. Dissolved oxygen concentration was at saturation (11–15 mg l⁻¹) in the top 3 m layer, but declined to near anoxic levels near the sediments. Dissolved oxygen concentrations in the deep lake were at saturation in most of the water column and approached anoxic levels near the sediments only. Nutrient concentrations in both lakes were fairly high, and similar in both lakes during ice cover. Total phosphorus concentrations generally ranged between 10–20 μg l⁻¹, NH₄-N between 16–100 μg l⁻¹, and DSi between 0.9–1.9 mg l⁻¹; these concentrations fell within summer ranges. NO₃-N concentrations were between 51–135 μg l⁻¹ during ice cover, but occurred at trace concentrations (<0.002 μg l⁻¹) during the summer. The winter phytoplankton community of both lakes was dominated by flagellates (cryptophytes, chrysophytes) and occasionally diatoms. Dinoflagellates, Cyanobacteria and green algae were poorly represented. Cryptophytes often occurred in fairly high proportions (20–80%) throughout the water column, whereas chrysophytes were more abundant just beneath the ice. Zooplankton population densities were extremely low during ice cover (compared to maximum densities measured in spring or summer) in both lakes, and were comprised largely of copepods.