Denitrification of a landfill leachate with high nitrate concentration in an anoxic rotating biological contactor

The denitrification performance of a lab-scale anoxic rotating biological contactor (RBC) using landfill leachate with high nitrate concentration was evaluated. Under a carbon to nitrogen ratio (C/N) of 2, the reactor achieved N-NO₃ ⁻ removal efficiencies above 95% for concentrations up to 100 mg N-NO₃ ⁻ l⁻¹. The highest observed denitrification rate was 55 mg N-NO₃ ⁻ l⁻¹ h⁻¹ (15 g N-NO₃ ⁻ m⁻² d⁻¹) at a nitrate concentration of 560 mg N-NO₃ ⁻ l⁻¹. Although the reactor has revealed a very good performance in terms of denitrification, effluent chemical oxygen demand (COD) concentrations were still high for direct discharge. The results obtained in a subsequent experiment at constant nitrate concentration (220 mg N-NO₃ ⁻ l⁻¹) and lower C/N ratios (1.2 and 1.5) evidenced that the organic matter present in the leachate was non-biodegradable. A phosphorus concentration of 10 mg P-PO₄ ³⁻ l⁻¹ promoted autotrophic denitrification, revealing the importance of phosphorus concentration on biological denitrification processes.     

Zinc and Iron Concentration and SOD Activity in Human Semen and Seminal Plasma

The aim of the present study was to measure zinc (Zn) and iron (Fe) concentration in human semen and superoxide dismutase (SOD) activity in seminal plasma and correlate the results with sperm quality. Semen samples were obtained from men (N = 168) undergoing routine infertility evaluation. The study design included two groups based on the ejaculate parameters. Group I (n = 39) consisted of males with normal ejaculate (normozoospermia), and group II (n = 129) consisted of males with pathological spermiogram. Seminal Zn and Fe were measured in 162 samples (group I, n = 38; group II, n = 124) and SOD activity in 149 samples (group I, n = 37; group II, n = 112). Correlations were found between SOD activity and Fe and Zn concentration, and between Fe and Zn concentration. SOD activity was negatively associated with volume of semen and positively associated with rapid progressive motility, nonprogressive motility, and concentration. Negative correlation was stated between Fe concentration and normal morphology. Mean SOD activity in seminal plasma of semen from men of group I was higher than in seminal plasma of semen from men of group II. Fe concentration was higher in teratozoospermic males than in males with normal morphology of spermatozoa in group II. Our results suggest that Fe may influence spermatozoa morphology.     

Potential causes of linkage disequilibrium in a European maize breeding program investigated with computer simulations

Knowledge about the forces generating and conserving linkage disequilibrium (LD) is important for drawing conclusions about the prospects and limitations of association mapping. The objectives of our research were to examine the importance of (1) selection, (2) mutation, and (3) genetic drift for generating LD in a typical maize breeding program. We conducted computer simulations based on genotypic data of Central European maize open-pollinated varieties which have played an important role as founders of the European flint heterotic group. The breeding scheme and the dimensioning underlying our simulations reflect essentially the maize breeding program of the University of Hohenheim. Results suggested that in a plant breeding program of the examined dimension and breeding scheme, genetic drift and selection are major forces generating LD. The currently used population-based association mapping tests do not explicitly correct for LD caused by these two forces. Therefore, increased type I error rates are expected if these tests are applied to plant breeding populations. As a consequence, we recommend to use family-based association tests for association mapping approaches in plant breeding populations.     

Prospective survey of veterinary practitioners’ primary assessment of equine colic: clinical features,diagnoses, and treatment of 120 cases of large colon impaction

Background

Large colon impactions are a common cause of colic in the horse. There are no scientific reports on the clinical presentation, diagnostic tests and treatments used in first opinion practice for large colon impaction cases. The aim of this study was to describe the presentation, diagnostic approach and treatment at the primary assessment of horses with large colon impactions.

Methods

Data were collected prospectively from veterinary practitioners on the primary assessment of equine colic cases over a 12 month period. Inclusion criteria were a diagnosis of primary large colon impaction and positive findings on rectal examination. Data recorded for each case included history, signalment, clinical and diagnostic findings, treatment on primary assessment and final case outcome. Case outcomes were categorised into three groups: simple medical (resolved with single treatment), complicated medical (resolved with multiple medical treatments) and critical (required surgery, were euthanased or died). Univariable analysis using one-way ANOVA and Tukey’s post-hoc test, Kruskal Wallis with Dunn’s post-hoc test and Chi squared analysis were used to compare between different outcome categories.

Results

1032 colic cases were submitted by veterinary practitioners: 120 cases met the inclusion criteria for large colon impaction. Fifty three percent of cases were categorised as simple medical, 36.6% as complicated medical, and 9.2% as critical. Most cases (42.1%) occurred during the winter. Fifty nine percent of horses had had a recent change in management, 43% of horses were not ridden, and 12.5% had a recent / current musculoskeletal injury. Mean heart rate was 43bpm (range 26-88) and most cases showed mild signs of pain (67.5%) and reduced gut sounds (76%). Heart rate was significantly increased and gut sounds significantly decreased in critical compared to simple medical cases (p<0.05). Fifty different treatment combinations were used, with NSAIDs (93%) and oral fluids (71%) being administered most often.

Conclusions

Large colon impactions typically presented with mild signs of colic; heart rate and gut sounds were the most useful parameters to distinguish between simple and critical cases at the primary assessment. The findings of seasonal incidence and associated management factors are consistent with other studies. Veterinary practitioners currently use a wide range of different treatment combinations for large colon impactions.

     

Effects of three biological control approaches and their combination on the restoration of eutrophicated waterbodies

Choosing appropriate approaches is a key to successfully using biological control measures to accelerate the recovery of eutrophic waterbodies. In this study, we used three biomanipulation approaches—including introducing filter-feeding bivalves, stocking planktivorous fish, replanting submerged macrophytes—as well as an approach that combined all three of these methods in order to investigate their effects on water quality and plankton communities within simulation experiment systems. The experimental results showed that only stocking filter-feeding bivalves or fish could not significantly control the total algal biomass and water nutrient concentrations compared to those of the controls. The cladoceran biomasses were reduced under the treatments of stocking filter-feeding bivalves or fish. However, replanting macrophytes and a combined biological restoration approach could significantly reduce the algal biomass and the nutrient content, and both of these methods increased cladoceran biomass. The results of factor analysis of ten environmental parameters suggested that a combined biological restoration treatment was the most effective at controlling the algal biomass and reducing the nutrient content. In conclusion, combination of biological restoration measures was the best treatment out of the three treatments that were tested, and we suggest that more whole-lake scale experiments are needed. Additionally, designing a combined approach should not be a simple superposition of individual measures, but the measures should be complementary to each other.     

Cytotoxicity,apoptosis, DNA damage and methylation in mammary and kidney epithelial cell lines exposed to ochratoxin A

This study aimed to investigate the in vitro damage induced by ochratoxin A (OTA) in BME-UV1 and MDCK epithelial cells. Both cells lines were treated with OTA (0 up to 10 μg/mL), and cell viability (MTT assay), membrane stability (lactate dehydrogenase (LDH) release assay) and apoptotic cell rate (Tunel assay) were investigated. Further, the effect of the incubation with OTA has been evaluated at DNA level by the determination of DNA integrity, by the quantification of DNA adduct formation (8-hydroxy-2′-deoxyguanosine (8-OHdG)) and by the assessment of the global DNA methylation status (5-methyl-cytosine (5-mC)). The obtained results showed that after 24 h of OTA treatment, BME-UV1 cell viability was reduced in a dose-dependent way. OTA significantly (P?<?0.05) increased LDH release in BME-UV1 cells at all concentrations tested. OTA (1.25 μg/mL) induced 35 % LDH release in MDCK cells (P?<?0.05). A significant (P?<?0.05) change in percentages of apoptotic BME-UV1 (10?±?0.86) and MDCK (25?±?0.88) cells was calculated when the cells were co-incubated with OTA. The level of 8-OHdG adduct formation was significantly (P?<?0.05) increased in BME-UV1 cells treated with 1.25 μg/mL of OTA. The results of the present study suggest that a different mechanism of action may occur in these cell lines.

Open image in new window

Graphical abstract Study results overview

     

巴尔通体在滇西南蝙蝠中高度流行并具有丰富的遗传变异特征

蝙蝠是很多病原微生物的自然宿主, 全球多项研究表明蝙蝠是巴尔通体(Bartonella species)的主要宿主。为了解滇西南地区蝙蝠中巴尔通体的流行特征, 我们于2015-2017年间在云南省4个地区应用网捕法捕获蝙蝠3种305只。经种类鉴定后采集肝脾组织, 提取核酸, 通过TaqMan实时荧光定量PCR方法检测巴尔通体的tmRNA基因ssrA, 并进行测序鉴定和系统发育分析。结果发现172只蝙蝠检出该基因, 总感染率为56.4%; 其中临沧、西双版纳、保山和瑞丽4个采样点的蝙蝠感染率分别为50.0% (22/44)、61.7% (29/47)、62.1% (18/29)和55.7% (103/185)。中菊头蝠(Rhinolophus affinis)、小菊头蝠(R. blythi)和棕果蝠(Rousettus leschenaultii)的感染率分别为50.0% (22/44)、62.1% (18/29)和56.9% (132/232), 差异没有统计学意义(χ² = 1.135, P = 0.567), 表明巴尔通体在云南当地的蝙蝠种群中高度流行。定量PCR扩增产物2次扩增后测序获得37个巴尔通体ssrA序列, 属于10个系统发育分支, 其中1个为伊丽莎白巴尔通体(B. elizabethae)、特利波契巴尔通体(B. tribocorum)和克拉斯诺夫巴尔通体(B. krasnovii)的近缘种。其余序列与已知巴尔通体距离较远, 与亚洲、欧洲和美洲等其他地域来源于蝙蝠的巴尔通体近缘。遗传多样性分析显示, ssrA基因的核苷酸多样性指数(π)为0.11381 ± 0.00928, 基因型多样性指数(Hd)为0.985 ± 0.010, 形成29个基因型(单倍型), 说明云南蝙蝠巴尔通体具有丰富的遗传多样性。通过对本研究标本与全球相关序列的系统发育网络重建, 分析全球蝙蝠巴尔通体的地理和宿主分布特征, 可以看出巴尔通体与蝙蝠之间存在显著的宿主特异性关联。因此可初步确定蝙蝠-巴尔通体具有协同进化特征, 同时受到地理隔离的影响。     

Fungus mediated synthesis of gold nanoparticles and their conjugation with genomic DNA isolated from Escherichia coli and Staphylococcus aureus

Biological systems employing microorganisms have been used as an alternative to conventional chemical techniques for synthesizing gold nanoparticles. In the present study, gold nanoparticles have been synthesized from the supernatant broth (SB) and live cell filtrate (LCF) of the industrially important fungus Penicillium rugulosum. Additionally, potato dextrose broth (PDB) medium which is used for the growth of the fungus has also been able to synthesize gold nanoparticles. The size of the particles has been investigated by Bio-TEM before purification as well as after purification to find the difference in morphology pattern of the nanoparticles. Different characterization techniques like X-ray diffraction (XRD), infra-red (FTIR), X-ray photoelectron (XPS) and UV–vis spectroscopy have been used for analysis of the particles. SB of the fungus has yielded nanoparticles with better morphology and hence further optimization studies were conducted for controlling the size and shape of the above by altering pH and concentration of gold salt. A pH range of 4–6 has favored the synthesis process whereas increasing concentration of gold salt (beyond 2 mM) has resulted in the formation of bigger sized and aggregated nanoparticles. The optimized nanoparticles have been used to conjugate with isolated genomic DNA of bacteria Escherichia coli and Staphylococcus aureus. Visual observation of agarose gel electrophoresis images confirmed the binding of gold nanoparticles (4 μL and 6 μL) with isolated DNA (2 μL) fragments of both the organisms. The slight red shift of the surface plasmon (SP) band and minor aggregations noticed in Bio-TEM images for the DNA conjugated gold nanoparticles indicates that the genomic DNA could stabilize the particles against aggregation owing to negatively charged phosphate backbone.