Evaluation of Mercury Contamination in Fungi Boletus Species from Latosols,Lateritic Red Earths,and Red and Yellow Earths in the Circum-Pacific Mercuriferous Belt of Southwestern China

For the first time, highly elevated levels of mercury (Hg) have been documented for several species of the edible Fungi genus Boletus growing in latosols, lateritic red earths, and red and yellow earths from the Yunnan province of China. Analysis of Hg concentrations in the genus suggests that geogenic Hg is the dominant source of Hg in the fungi, whereas anthropogenic sources accumulate largely in the organic layer of the forest soil horizon. Among the 21 species studied from 32 locations across Yunnan and 2 places in Sichuan Province, the Hg was found at elevated level in all samples from Yunnan but not in the samples from Sichuan, which is located outside the mercuriferous belt. Particularly abundant in Hg were the caps of fruiting bodies of Boletus aereus (up to 13 mg kg^-1 dry matter), Boletus bicolor (up to 5.5 mg kg^-1 dry matter), Boletus edulis (up to 22 mg kg^-1 dry matter), Boletus luridus (up to 11 mg kg^-1 dry matter), Boletus magnificus (up to 13 mg kg^-1 dry matter), Boletus obscureumbrinus (up to 9.4 mg kg^-1 dry matter), Boletus purpureus (up to 16 mg kg^-1 dry matter), Boletus sinicus (up to 6.8 mg kg^-1 dry matter), Boletus speciosus (up to 4.9mg kg^-1 dry matter), Boletus tomentipes (up to 13 mg kg^-1 dry matter), and Boletus umbriniporus (up to 4.9 mg kg^-1 dry matter). Soil samples of the 0–10 cm topsoil layer from the widely distributed locations had mercury levels ranging between 0.034 to 3.4 mg kg^-1 dry matter. In Yunnan, both the soil parent rock and fruiting bodies of Boletus spp. were enriched in Hg, whereas the same species from Sichuan, located outside the mercuriferous belt, had low Hg concentrations, suggesting that the Hg in the Yunnan samples is mainly from geogenic sources rather than anthropogenic sources. However, the contribution of anthropogenically-derived Hg sequestered within soils of Yunnan has not been quantified, so more future research is required. Our results suggest that high rates of consumption of Boletus spp. from Yunnan can deliver relatively high doses of Hg to consumers, but that rates can differ widely because of large variability in mercury concentrations between species and locations.     

A study on human serum albumin influence on glycation of fibrinogen

Although in vivo glycation proceeds in complex mixture of proteins, previous studies did not take in consideration the influence of protein–protein interaction on Maillard reaction. The aim of our study was to test the influence of human serum albumin (HSA) on glycation of fibrinogen. The isotopic labeling using [¹³C₆] glucose combined with LC-MS were applied as tool for identification possible glycation sites in fibrinogen and for evaluation the effect of HSA on the glycation level of selected amino acids in fibrinogen.     

Evolution of the Selfing Syndrome in Arabis alpina (Brassicaceae)

Introduction

The transition from cross-fertilisation (outcrossing) to self-fertilisation (selfing) frequently coincides with changes towards a floral morphology that optimises self-pollination, the selfing syndrome. Population genetic studies have reported the existence of both outcrossing and selfing populations in Arabis alpina (Brassicaceae), which is an emerging model species for studying the molecular basis of perenniality and local adaptation. It is unknown whether its selfing populations have evolved a selfing syndrome.

Methods

Using macro-photography, microscopy and automated cell counting, we compared floral syndromes (size, herkogamy, pollen and ovule numbers) between three outcrossing populations from the Apuan Alps and three selfing populations from the Western and Central Alps (Maritime Alps and Dolomites). In addition, we genotyped the plants for 12 microsatellite loci to confirm previous measures of diversity and inbreeding coefficients based on allozymes, and performed Bayesian clustering.

Results and Discussion

Plants from the three selfing populations had markedly smaller flowers, less herkogamy and lower pollen production than plants from the three outcrossing populations, whereas pistil length and ovule number have remained constant. Compared to allozymes, microsatellite variation was higher, but revealed similar patterns of low diversity and high Fis in selfing populations. Bayesian clustering revealed two clusters. The first cluster contained the three outcrossing populations from the Apuan Alps, the second contained the three selfing populations from the Maritime Alps and Dolomites.

Conclusion

We conclude that in comparison to three outcrossing populations, three populations with high selfing rates are characterised by a flower morphology that is closer to the selfing syndrome. The presence of outcrossing and selfing floral syndromes within a single species will facilitate unravelling the genetic basis of the selfing syndrome, and addressing which selective forces drive its evolution.     

云南常见牛肝菌属真菌中汞含量及食用安全评价

汞(Hg)是危害人类健康的主要重金属元素之一,多数食用菌对Hg有很强的富集能力,测定食用菌中Hg含量,并对其进行食用安全性评价具有重要意义。采用冷原子吸收直接测汞仪系统测定85份云南常见牛肝菌属真菌菌盖、菌柄中总Hg含量;以同一牛肝菌子实体菌盖与菌柄总Hg含量比(Q(C/S))分析牛肝菌属真菌对Hg的富集特征;根据联合国粮农组织和世界卫生组织(FAO/WHO)现行每周Hg允许摄入量(provisional tolerable weekly intake,PTWI)标准和中国GB 2762—2012规定的食用菌中Hg限量标准评价样品的食用安全性。结果表明,菌盖和菌柄中总Hg含量分别在0.13~22.00、0.20~8.40 mg·kg-1DW,不同产地、种类及不同采集年份的样品中总Hg含量存在明显差异;同一牛肝菌菌盖、菌柄总Hg含量比(Q(C/S))在0.28~4.08,92%的样品Q(C/S)1,表明多数样品中菌盖对Hg的富集能力强于菌柄。根据GB 2762—2012规定的食用菌及其制品中总Hg含量限量标准(≤0.1 mg·kg-1),发现所有测试样品的总Hg含量均超标;根据PTWI标准,假设成年人(60 kg)每周食用300 g新鲜牛肝菌,则多数样品Hg摄入量低于允许摄入量,无安全风险,而少数样品Hg摄入量高于允许摄入量,食用有一定的潜在风险。同时,牛肝菌总Hg含量与种类、产地、采集时间等因素密切相关,采食及安全评价需综合考虑这些因素。     

Structural studies of the C‐terminal 19‐peptide of serum amyloid A and its Pro→Ala variants interacting with human cystatin C

Serum amyloid A (SAA) is a multifunctional acute‐phase protein whose concentration in serum increases markedly following a number of chronic inflammatory and neoplastic diseases. Prolonged high SAA level may give rise to reactive systemic amyloid A (AA) amyloidosis, where the N‐terminal segment of SAA is deposited as amyloid fibrils. Besides, recently, well‐documented association of SAA with high‐density lipoprotein or glycosaminoglycans, in particular heparin/heparin sulfate (HS), and specific interaction between SAA and human cystatin C (hCC), the ubiquitous inhibitor of cysteine proteases, was proved. Using a combination of selective proteolytic excision and high‐resolution mass spectrometry, a hCC binding site in the SAA sequence was determined as SAA(86–104). The role of this SAA C‐terminal fragment as a ligand‐binding locus is still not clear. It was postulated important in native SAA folding and in pathogenesis of AA amyloidosis. In the search of conformational details of this SAA fragment, we did its structure and affinity studies, including its selected double/triple Pro→Ala variants. Our results clearly show that the SAA(86–104) 19‐peptide has rather unordered structure with bends in its C‐terminal part, which is consistent with the previous results relating to the whole protein. The results of affinity chromatography, fluorescent ELISA‐like test, CD and NMR studies point to an importance of proline residues on structure of SAA(86–104). Conformational details of SAA fragment, responsible for hCC binding, may help to understand the objective of hCC–SAA complex formation and its importance for pathogenesis of reactive amyloid A amyloidosis. Copyright © 2015 John Wiley & Sons, Ltd.     

Urinary Metal Levels with Relation to Age,Occupation, and Smoking Habits of Male Inhabitants of Eastern Iran

Biological Trace Element Research - In low-income and middle-income countries such as Iran, smoking is becoming increasingly popular, especially among young people. This has led to additional...     

Pharmacological Profile of the “Triple” Monoamine Neurotransmitter Uptake Inhibitor, DOV 102,677

Summary 1. The molecular and behavioral pharmacology of DOV 102,677 is characterized.2. This characterization was performed using radioligand binding and neurotransmitter uptake assays targeting the monoamine neurotransmitter receptors. In addition, the effects of DOV 102,677 on extracellular neurotransmitter levels were investigated using in vivo microdialysis. Finally, the effects of DOV 102,677 in the forced swim test, locomotor function, and response to prepulse inhibition was investigated.3. DOV 102,677 is a novel, “triple” uptake inhibitor that suppresses [³H]dopamine (DA), [³H]norepinephrine (NE) and [³H]serotonin (5-HT) uptake by recombinant human transporters with IC₅₀ values of 129, 103 and 133 nM, respectively. Radioligand binding to the dopamine (DAT), norepinephrine (NET), and serotonin (SERT) transporters is inhibited with k _i values of 222, 1030, and 740 nM, respectively. DOV 102,677 (20 mg/kg IP) increased extracellular levels of DA and 5-HT in the prefrontal cortex to 320 and 280% above baseline 100 min after administration. DA levels were stably increased for the duration (240 min) of the study, but serotonin levels declined to baseline by 200 min after administration. NE levels increased linearly to a maximum of 348% at 240 min post-dosing. Consistent with these increases in NE levels, the density of β-adrenoceptors was selectively decreased in the cortex of rats treated with DOV 102,677 (20 mg/kg per day, PO, 35 days).4. DOV 102,677 dose-dependently reduced the amount of time spent immobile by rats in the forced swim test, a model predictive of antidepressant activity, with a minimum effective dose (MED) of 20 mg/kg and a maximal efficacy comparable to imipramine. This decrease in immobility time did not appear to result from increased motor activity. Further, DOV 102,677 was as effective as methylphenidate in reducing the amplitude of the startle response in juvenile mice, without notably altering motor activity.5. In summary, DOV 102,677 is an orally active, “balanced” inhibitor of DAT, NET and SERT with therapeutic versatility in treating neuropsychiatric disorders beyond depression.     

ParA of Mycobacterium smegmatis co‐ordinates chromosome segregation with the cell cycle and interacts with the polar growth determinant DivIVA

Mycobacteria are among the clinically most important pathogens, but still not much is known about the mechanisms of their cell cycle control. Previous studies suggested that the genes encoding ParA and ParB (ATPase and DNA binding protein, respectively, required for active chromosome segregation) may be essential in Mycobacterium tuberculosis. Further research has demonstrated that a Mycobacterium smegmatis parB deletion mutant was viable but exhibited a chromosome segregation defect. Here, we address the question if ParA is required for the growth of M. smegmatis, and which cell cycle processes it affects. Our data show that parA may be deleted, but its deletion leads to growth inhibition and severe disturbances of chromosome segregation and septum positioning. Similar defects are also caused by ParA overproduction. EGFP–ParA localizes as pole‐associated complexes connected with a patch of fluorescence accompanying two ParB complexes. Observed aberrations in the number and positioning of ParB complexes in the parA deletion mutant indicate that ParA is required for the proper localization of the ParB complexes. Furthermore, it is shown that ParA colocalizes and interacts with the polar growth determinant Wag31 (DivIVA homologue). Our results demonstrate that mycobacterial ParA mediates chromosome segregation and co‐ordinates it with cell division and elongation.     

A novel method for cloning of coding sequences of highly toxic proteins

Background

During standard gene cloning, the recombinant protein appearing in bacteria as the result of expression leakage very often inhibits cell proliferation leading to blocking of the cloning procedure. Although different approaches can reduce transgene basal expression, the recombinant proteins, which even in trace amounts inhibit bacterial growth, can completely prevent the cloning process.