Neonatal exposure to bisphenol A advances pubertal development in female rats

Neonatal exposure to bisphenol A (BPA) is hypothesized to advance pubertal development. However, the effects of neonatal BPA exposure on pubertal development has not been described. In this study, female Sprague‐Dawley rats were exposed to 0.05, 0.5, 5, or 10 mg·kg^?1·day^?1 BPA, or corn oil vehicle alone from postnatal day 1 (PND1) to PND10 via subcutaneous injection. We evaluated day of vaginal opening (DVO), ovarian morphology, serum hormone concentrations, and hypothalamic expression of Gnrh1 and Kiss1 in female rats at PND35. DVO was significantly advanced in rats exposed to 5 and 10 mg·kg^?1·day^?1 BPA. Serum hormone concentrations increased as BPA dose increased. Additionally, hypothalamic Gnrh1 and Kiss1 expression were increased with BPA exposure; rats exposed to 10 mg·kg^?1·day^?1 BPA had significantly upregulated hypothalamic Gnrh1 and Kiss1 expressions in terms of both messenger RNA and protein levels. Our results suggest that exposure to a 10 mg·kg^?1·day^?1 dose of BPA might advance pubertal development significantly. In addition, within the range of 0 to 10 mg·kg^?1·day^?1, neonatal exposure to BPA may affect pubertal development in a dose‐dependent manner.     

Does radial oxygen loss and iron plaque formation on roots alter Cd and Pb uptake and distribution in rice plant tissues?

Background and Aims

Metal (e.g. Cd and Pb) pollution in agricultural soils and crops have aroused considerable attention in recent years. This study aimed to evaluate the effects of ROL and Fe plaque on Cd and Pb accumulation and distribution in the rice plant.

Methods

A rhizobag experiment was employed to investigate the correlations among radial oxygen loss (ROL), Fe plaque formation and uptake and distribution of Cd and Pb in 25 rice cultivars.

Results

Large differences between the cultivars were found in rates of ROL (1.55 to 6.88 mmol O₂ kg^?1 root d.w. h^?1), Fe plaque formation (Fe: 6,117–48,167 mg kg^?1; Mn: 127–1,089 mg kg^?1), heavy metals in shoot (Cd: 0.13–0.35 mg kg^?1; Pb: 4.8–8.1 mg kg^?1) and root tissues (Cd: 1.1–3.5 mg kg^?1; Pb: 45–199 mg kg^?1), and in Fe plaque (Cd: 0.54–2.6 mg kg^?1; Pb: 102–708 mg kg^?1). Rates of ROL were positively correlated with Fe plaque formation and metal deposition on root surfaces, but negatively correlated with metal transfer factors of root/plaque and distributions in shoot and root tissues.

Conclusions

ROL-induced Fe plaque promotes metal deposition on to root surfaces, leading to a limitation of Cd and Pb transfer and distribution in rice plant tissues.     

Improved microspore embryogenesis induction and plantlet regeneration using putrescine,cefotaxime and vancomycin in Brassica napus L.

The effects of three periods of exposure (12, 24 and 48 h) to different levels of putrescine (0, 0.2, 0.5, 1.0, 2.0 and 5.0 mg l^?1), as well as three incubation periods (24, 48 and 72 h) to different levels of cefotaxime and vancomycin (0, 50, 100, 200 and 500 mg l^?1) on microspore embryogenesis of rapeseed cv. ‘Hyola 401’ were assessed. Microspore embryogenesis was enhanced about threefold compared with untreated culture following 48 h treatment with 0.2 mg l^?1 putrescine. Putrescine treatment at 0.5 mg l^?1 for 48 h effectively induced root formation and increased normal plantlet regeneration by 92 % when microspore-derived embryos (MDEs) were transferred to regeneration medium. The highest embryo yield (184.2 embryos Petri dish^?1) was possible when induction medium was supplemented with 50 mg l^?1 cefotaxime for 24 h and the highest normal regeneration was observed in cultures exposed to 50 and 100 mg l^?1 at all durations tested. More abnormal MDEs (76 and 82 %) were observed when microspores treated with 200 and 500 mg l^?1 cefotaxime many of which failed to regenerate normally and resulted in callusing. Vancomycin at 100 mg l^?1 during the 48 h exposure increased the number of MDEs (181.6 embryos Petri dish^?1) in contrast to untreated cultures (93.6 embryos Petri dish^?1) but, normal plantlet regeneration decreased as vancomycin level increased and high callusing (84 and 90 %) was observed with 200 and 500 mg l^?1 for 72 h. Microspore embryogenesis and plant regeneration could be improved by putrescine, cefotaxime and vancomycin when appropriate levels and durations of incubation were selected.     

Effects of ascorbic acid,alpha-tocopherol,and glutathione on microspore embryogenesis in Brassica napus L.

The impact of culture conditions and addition of antioxidants to media on microspore embryogenesis in rapeseed (Brassica napus cv. ‘PF704’) was investigated. Different concentrations of ascorbic acid (0, 5, 10, 20, 50, 100, and 200 mg l^?1) and alpha (α)-tocopherol (0, 5, 10, 20, 50, 100, and 200 mg l^?1) were evaluated along with two temperature pretreatments (18 d at 30°C; 2 d at 32.5°C followed by 16 d at 30°C). In addition, combinations of reduced glutathione (0, 10, 50, and 100 mg l^?1) and ascorbic acid (5 and 10 mg l^?1) were tested. Microspore embryogenesis was significantly enhanced using 10 mg l^?1 ascorbic acid (334 embryos per Petri dish) compared with untreated cultures (184 embryos per Petri dish) at 30°C. α-Tocopherol (5 and 10 mg l^?1) enhanced (312 and 314 embryos per Petri dish, respectively) microspore embryogenesis relative to untreated cultures (213 embryos per Petri dish) at 30°C, although there were no significant differences among cultures treated with 5–50 mg l^?1 α-tocopherol. When 50 mg l^?1 α-tocopherol was combined with 5 or 10 mg l^?1 ascorbic acid, embryogenesis was significantly enhanced (308 and 328 embryos per Petri dish, respectively) relative to other ascorbic acid levels. Moreover, 10 mg l^?1 of reduced glutathione and 5 mg l^?l ascorbic acid enhanced microspore embryogenesis (335 embryos per Petri dish) compared to cultures without reduced glutathione (275 embryos per Petri dish). Microspore embryogenesis could be improved by adding ascorbic acid, α-tocopherol, and reduced glutathione when the appropriate combination and temperature pretreatment were selected.     

Differential Activity of Nivolumab,Pembrolizumab and MPDL3280A according to the Tumor Expression of Programmed Death-Ligand-1 (PD-L1): Sensitivity Analysis of Trials in Melanoma,Lung and Genitourinary Cancers

Background

The potential predictive role of programmed death-ligand-1 (PD-L1) expression on tumor cells in the context of solid tumor treated with checkpoint inhibitors targeting the PD-1 pathway represents an issue for clinical research.

Methods

Overall response rate (ORR) was extracted from phase I-III trials investigating nivolumab, pembrolizumab and MPDL3280A for advanced melanoma, non-small cell lung cancer (NSCLC) and genitourinary cancer, and cumulated by adopting a fixed and random-effect model with 95% confidence interval (CI). Interaction test according to tumor PD-L1 was accomplished. A sensitivity analysis according to adopted drug, tumor type, PD-L1 cut-off and treatment line was performed.

Results

Twenty trials (1,475 patients) were identified. A significant interaction (p<0.0001) according to tumor PD-L1 expression was found in the overall sample with an ORR of 34.1% (95% CI 27.6-41.3%) in the PD-L1 positive and 19.9% (95% CI 15.4-25.3%) in the PD-L1 negative population. ORR was significantly higher in PD-L1 positive in comparison to PD-L1 negative patients for nivolumab and pembrolizumab, with an absolute difference of 16.4% and 19.5%, respectively. A significant difference in activity of 22.8% and 8.7% according to PD-L1 was found for melanoma and NSCLC, respectively, with no significant difference for genitourinary cancer.

Conclusion

Overall, the three antibodies provide a significant differential effect in terms of activity according to PD-L1 expression on tumor cells. The predictive value of PD-L1 on tumor cells seems to be more robust for anti-PD-1 antibody (nivolumab and pembrolizumab), and in the context of advanced melanoma and NSCLC.     

Temporal-spatial distribution,environmental significance and release risks of phosphorus in the sediments of a tropical mountain’s deep drinking water reservoir in southeastern China

In this study, the fractionation and distribution of phosphorus (P) in the core sediments of the Shanmei reservoir were investigated by using the chemical extraction method in directions for the first time in order to understand its bio-availability, adsorption characteristics, potential release and environmental significance. The results of the study showed that P in the sediments mainly consisted of inorganic phosphorus (IP) and that IP mainly consisted of non-apatite phosphorus (NAIP). The horizontal and temporal distributions of the P fractions were different from each other, but the vertical distribution was similar, which indicated a trend of stabilization after falling. The content of total phosphorus (TP), IP, organic phosphorus (OP), NAIP, apatite phosphorus (AP), and bio-available phosphorus (BAP) in the sediments during the three seasons ranged from 193.85 to 1664.05 mg·kg^?1, 126.90 to 1127.70 mg·kg^?1, 43.74 to 669.29 mg·kg^?1, 57.62 to 937.07 mg·kg^?1, 32.58 to 250.71 mg·kg^?1, and 41.06 to 871.82 mg·kg^?1, respectively. NAIP contents in the sediments accounted for more than 50% of TP. Using an analysis from three aspects, the eutrophication risk index (ERI) could be used to assess the potential release of P in the sediments, and there was a high release risk of P in the sediments in the Shanmei reservoir.     

Caffeine antagonizes several central effects of diazepam

In spinal cats, caffeine (3–30 mg·kg^?1 i.v.) reduced the increase of dorsal root potentials (DRPs) caused by diazepam (0.1–1 mg·kg^?1 i.v.) without affecting the prolongation of DRPs evoked by phenobarbitone (10–20 mg·kg^?1 i.v.). Caffeine antagonized the depression by diazepam, but not that by phenobarbitone, of the ventral root-evoked Renshaw cell discharge. In unrestrained cats, 50 mg·kg^?1 caffeine i.p. abolished the elevation induced by 1 mg·kg^?1 diazepam i.p. of the threshold for eliciting a rage reaction by stimulation of the lateral hypothalamus, but was ineffective against the threshold increase caused by 20 mg·kg^?1 phenobarbitine i.p. In the horizontal wire test in mice, caffeine was more potent in reversing the depression of performance induced by diazepam that that by phenobarbitone (ED50 1.8 mg·kg^?1 and 139 mg·kg^?1 p.o., respectively). The reduction of skeletal muscle tone in mice produced by diazepam was antagonized by low doses of caffeine (ED50 0.53 mg·kg^?1 p.o.). While caffeine at low doses (0.3-3 mg·kg^?1 p.o.) abolished the anticonflict effect of diazepam in rats, high doses (ED50 160 mg·kg^?1 p.o.) were necessary to antagonize the anticonvulsant effect of diazepam on pentylene-tetrazole-induced seizures in mice. The interaction between caffeine and diazepam is not due to a competition at the benzodiazepine receptors but may involve purinergic mechanisms.     

Performance and tissue fatty acid profiles in veal calves fed diets supplemented with conjugated linoleic acids

Three groups of six calves each were fed a milk replacer at 0.8 kg and a starter concentrate ad libitum. Calves of the control group received the basal diet supplemented with rapeseed oil at 10 g per kg of feed solids. Calves of treatment groups were fed diets supplemented with a synthetically produced oil containing 62.3% methyl esters of CLA. The CLA-oil was added to milk at expense of rapeseed oil and fed at 5 and 10 g · kg^?1 feed solids for 63 days. Calves were slaughtered at 115 days of age. There was no significant effect of CLA on growth, intake of starter, feed conversion, chemical composition of meat and its oxidative stability. Dietary supplementation with CLA at 10 g · kg^?1 significantly increased CLA content in m. longissimus dorsi (MLD) from 5.6 to 19.3 mg · 100 g^?1, in liver from 13.1 to 68.8 mg · 100 g^?1, and in perirenal fat from 0.37 to 3.17 g · 100 g^?1. Dietary CLA decreased the ratio of cis-9, trans-11 and trans-10, cis-12 isomers of CLA in tissues, concentration of monounsaturated fatty acids in the MLD and fat, as well as the concentration of fatty acids with 20 and 22 carbon atoms. It can be concluded that in veal calves unprotected CLA apparently escaped ruminal hydrogenation, but was preferentially incorporated into depot fat.     

Growth and Flowering Responses of Sea Marigold to Daminozide,Paclobutrazol, or Uniconazole Applied as Drenches or Sprays

Borrichia frutescens (L.) DC., sea marigold, is a woody perennial shrub native to the Gulf and Atlantic coasts of North America and has potential as a landscape shrub or groundcover. This study assesses application rates of three commercially available plant growth regulators (PGRs) on B. frutescens during container production. In one experiment, plants were drenched with 0, 0.5, 1, 2, or 4 mg active ingredient (a.i.) pot^?1 of uniconazole or 0, 5, 10, 20, or 40 mg a.i. pot^?1 of paclobutrazol, and in a second experiment, plants were sprayed with solutions of either 0, 25, 50, 100, or 200 mg a.i. L^?1 of uniconazole, 0, 50, 100, 200, or 400 mg a.i. L^?1 of paclobutrazol, or 0, 2500, 5000, 10000, or 20000 mg a.i. L^?1 of daminozide. Drench-applied paclobutrazol (40 mg a.i. pot^?1) reduced shoot mass and root mass (52.9 and 48.5 %, respectively). Both paclobutrazol (40 mg a.i. pot^?1) and uniconazole (2 mg a.i. pot^?1) reduced leaf number by as much as 56.7 and 23.8 %, respectively. Height was reduced 54.9 % by paclobutrazol at 40 mg a.i. pot^?1 and 34.9 % by uniconazole at 2 mg a.i. pot^?1. Drench application of paclobutrazol and uniconazole reduced internode extension by 50.1 and 41.4 %, respectively. At the levels tested, daminozide, paclobutrazol, and uniconazole were generally ineffective at controlling growth when applied as a spray. Drench application of paclobutrazol or uniconazole can be used to control height during container production of B. frutescens, whereas spray application rates need to be tested at higher concentrations or multiple applications to achieve desired control.     

Plantlet formation via somatic embryogenesis and LC ESI Q-TOF MS determination of secondary metabolites in <Emphasis Type="Italic">Butea monosperma</Emphasis> (Lam.) Kuntze

Medicinal properties of Butea monosperma (BM) and overexploitation of bark as a rich source of flavonoids for different biological activities, development of efficient method for high frequency somatic embryos and in vitro synthesis of bioactive secondary metabolites using plant tissue culture technology is important. Initially, callus was induced from leaf explants of BM on Murashige and Skoog (MS) medium containing 0.25 mg L^?1 2,4-d-dichlorophenoxyacetic acid (2,4-d) with 0.1 mg L^?1 kinetin (Kn) and ascorbic acid (AA). MS half strength macronutrients and full strength micronutrients containing 0.25 mg L^?1 2,4-d with 0.1 mg L^?1 Kn, and 0.5 mg L^?1 AA provided fragile callus with 84.0 ± 1.00 % optimal growth response. Shoot formation occurred via somatic embryogenesis through an intermediary callus phase. However, 2.1 mg L^?1 thidiazuron with 0.5 mg L^?1 AA provides high frequency (79.6 ± 2.02 %) of somatic embryogenesis within 5 weeks. Developed embryos when transferred to woody plant medium containing 0.5 mg L^?1 AA with 3.0 mg L^?1 Kn and 0.5 mg L^?1 α naphthalene acetic acid responded 44.0 ± 0.00 % embryo maturation, whereas 0.5 mg L^?1 Kn, 0.3 mg L^?1 indole-3-butyric acid, and 0.25 mg L^?1 AA induced rooting within 6 and 8 weeks, respectively. Liquid chromatography electro spray ionization quadrupole time of flight mass spectrometry (LC ESI Q-TOF MS) analysis of in vitro cultures showed similarity to those compounds identified in wild grown leaf samples known for osteogenic activity. Histological investigation through scanning electron microscopy demonstrates the developmental stages of somatic embryos, shoot bud formation, and induction of root primordial.     

A novel <Emphasis Type="Italic">Trichoderma</Emphasis> fusant for enhancing nutritional value and defence activity in chickpea

In recent years, due to the rise in food consumption, much of the attention has been focused to increase the yield of the agricultural crops which resulted in compromised nutritional quality. Efforts have to be undertaken to enhance the nutritional attributes of legumes, cereals and staple food crops by increasing amino acids and mineral content. In the present study, we evaluated a protoplast fusant (H. lixii MTCC 5659) for its ability to enhance nutritional value and defence activity in chickpea. Essential amino acids; methionine (9.82 mg kg^?1 dw), cysteine (2.61 mg kg^?1 dw), glycine (11.34 mg kg^?1 dw), valine (9.26 mg kg^?1 dw), and non-essential amino acids; aspartic acid (39.19 mg kg^?1 dw) and serine (17.53 mg kg^?1 dw) were significantly higher in seeds of fusant inoculated chickpea. Fusant significantly improved accumulation of mineral nutrients i.e. Cu (157.73 mg kg^?1 dw), Co (0.06 mg kg^?1 dw), Ni (1.85 mg kg^?1 dw), Zn (157.73 mg kg^?1 dw) and S (16.29 mg kg^?1 dw) in seeds. Biocontrol and defence activities of chickpea increased from 20 to 35% in fusant inoculated plants suggesting its potential to ameliorate biotic stress. To the best of our knowledge, this is the first report of an increase in amino acids and mineral content of chickpea by fusant inoculation.     

Effect of elicitation and precursor feeding on accumulation of 20-hydroxyecdysone in <Emphasis Type="Italic">Achyranthes aspera</Emphasis> Linn. cell suspension cultures

20-Hydroxyecdysone is one of the most common ecdysteroids in plants with potential therapeutic applications. In this study, cell suspension cultures of Achyranthes aspera were raised in shake flasks to investigate the production of 20-hydroxyecdysone. The quantification and characterization of 20-hydroxyecdysone in the cultures were done by High performance liquid chromatography (HPLC) and Liquid Chromatography-quadrupole time-of- flight mass spectrometry (LC-Q-TOF) analyses. For raising the suspension, calli initiated from in vitro grown leaf explants were cultured in liquid Murashige and Skoog (MS) medium augmented with combinations of 2, 4-dichlorophenoxyacetic acid (1 mg L^?1) and α-naphthaleneacetic acid (1 mg L^?1). Maximum growth index of the cell suspension was 9.9, which was achieved during 20th day of culture (final phase of exponential growth). At this stage, the biomass accumulated was 1.09 ± 0.09 g dry weight (DW) and the 20-hydroxyecdysone concentration was 0.24 mg g^?1 DW. Eliciting the cultures with 0.6 mM Methyl jasmonate for 6 days; enhanced the production of 20-hydroxyecdysone production to 0.35 mg g^?1 DW. By augmenting the cultures with the precursors namely cholesterol (10 mg L^?1) and 7-dehydrocholesterol (10 mg L^?1), production of 20-hydroxyecdysone was boosted to 0.31 mg g^?1 DW and 0.28 mg g^?1 DW respectively.     

Phytostabilization potential of ornamental plants grown in soil contaminated with cadmium

In a greenhouse experiment, five ornamental plants, Osmanthus fragrans (OF), Ligustrum vicaryi L. (LV), Cinnamomum camphora (CC), Loropetalum chinense var. rubrum (LC), and Euonymus japonicas cv. Aureo-mar (EJ), were studied for the ability to phytostabilization for Cd-contaminated soil. The results showed that these five ornamental plants can grow normally when the soil Cd content is less than 24.6 mg·kg^?1. Cd was mainly deposited in the roots of OF, LV, LC and EJ which have grown in Cd-contaminated soils, and the maximum Cd contents reached 15.76, 19.09, 20.59 and 32.91 mg·kg^?1, respectively. For CC, Cd was mainly distributed in the shoots and the maximum Cd content in stems and leaves were 12.5 and 10.71 mg·kg^?1, however, the total amount of Cd in stems and leaves was similar with the other ornamental plants. The enzymatic activities in Cd-contaminated soil were benefited from the five tested ornamental plants remediation. Soil urease and sucrase activities were improved, while dehydrogenase activity was depressed. Meanwhile, the soil microbial community was slightly influenced when soil Cd content is less than 24.6 mg·kg^?1 under five ornamental plants remediation. The results further suggested that ornamental plants could be promising candidates for phytostabilization of Cd-contaminated soil.     

Counter-Current Metal Leaching and Precipitation for Soil Remediation

Chemical acid leaching is an effective technique for extracting toxic metals from the finest fractions of polluted soils. Nevertheless, the use of large quantities of reagents and process water results in prohibitive operating costs. The purpose of this study was to evaluate the technical and economic advantages of recirculating water in a counter-current leaching process (CCLP). Five 1-h sulfuric acid extraction steps (at pH = 1.5) followed by three 5-min water-washing steps were applied to the fine particle fraction (<0.125 mm) of an industrial soil polluted by Cd (13.2 mg·kg^?1), Cu (3 100 mg·kg^?1), Mn (685 mg kg^?1), Pb (550 mg·kg^?1), and Zn (2 840 mg·kg^?1). The leaching experiments were carried out at ambient temperature using a 10% soil suspension and in 1-L working volume stirred tank reactors. This paper presents results of conventional and counter-current leaching process (CCLP) tests and shows that the CCLP yields removal results for Cu (85%), Zn (86%), Mn (75%), and Cd (90%) that are similar to those obtained using the conventional leaching process. Moreover, the CCLP uses half of the quantity of acid and one-eighth of the amount of water that the conventional process uses. Metal precipitation with NaOH and Ca(OH)₂ was applied to treat the acidic leachates, and good metal removal yields were achieved with both reagents. However, the large consumption of chemicals implies high operating costs. In addition, the precipitation causes considerable sludge production, particularly when using Ca(OH)₂. Overall, the CCLP coupled to metal precipitation using NaOH and water recycling appears to be the most attractive option for the removal of toxic metals from this industrial soil.     

Hygromycin promotes somatic embryogenesis in spinach

Hygromycin (hyg) at low doses (0.5–1.0 mg l^?1) promoted somatic embryogenesis from apical sections of spinach lateral roots. The highest promoting effect on both the frequency of regeneration and the mean number of somatic embryos (SE) per explant was achieved at 0.5 mg l^?1 hyg. With increasing the concentration of hyg to 1 mg l^?1, the regeneration frequency decreased, while the mean SE number remained significantly higher than in control (hyg-free medium). Complete inhibition of SE regeneration started at 7.5 mg l^?1 hyg. Moreover, hyg efficiently promoted the process of secondary somatic embryogenesis. Compared to control, a 2.75-fold increase in the secondary somatic embryo (SSE) mean number was obtained at 0.5 mg l^?1 hyg, and the increment was still discernible at 1.0 and 2.5 mg l^?1 hyg. Both primary SE and SSE explants became completely necrotic at 12.5 mg l^?1 hyg. Since attempts with direct selection at 20 mg l^?1 hyg proved unsuccessful, the results obtained in this study suggest that a stepwise selection procedure is suitable, starting with selection at 0.5 mg l^?1 hyg, to exploit the promoting effect of low hyg doses on SE regeneration from transformed cells, then gradually increasing the hyg concentration to 20 mg l^?1 for final selection. Complete SE and SSE explant mortality at hyg above 12.5 mg l^?1 guarantees a low possibility of escape during the selection process. This study will be useful for increasing the efficiency of transgenic plant regeneration following genetic transformation in spinach.     

Micropropagation, <Emphasis Type="Italic">in vitro</Emphasis> flowering,and tuberization in <Emphasis Type="Italic">Brachystelma glabrum</Emphasis> Hook.f., an endemic species

Brachystelma glabrum Hook.f. is an endemic plant species of Eastern Ghats, India. In this study, efficient protocols for in vitro micropropagation, flowering, and tuberization of this plant were developed. Sterilized shoot tip and nodal explants were cultured on Murashige and Skoog (MS) medium supplemented with different plant growth regulators (PGRs) and additives for shoot induction and multiplication. Both shoot tip and nodal explants showed the best response (90 and 100%, respectively) on MS medium supplemented with thidiazuron (TDZ) at 1.0 mg L^?1. The microshoots multiplied best on MS + TDZ (1.0 mg L^?1) in combination with α-naphthaleneacetic acid (NAA) at 0.5 mg L^?1 and coconut water (CW) at 25%. The highest number of in vitro flowers (4.0 flowers per microshoot) was observed on MS medium supplemented with a combination of N6-benzyladenine (BA) and indole-3-butyric acid (IBA), each at 1.5 mg L^?1. In vitro-derived shoots produced aerial tubers on MS + TDZ (2.0 mg L^?1) + IBA (0.5 mg L^?1) and basal tubers on MS + TDZ at 2.0 mg L^?1. In vitro shoots were best rooted on half-strength (½) MS + NAA at 0.5 mg L^?1. The rooted plantlets were successfully acclimatized in pots with 70% survival after a hardening period of 1 mo. This protocol provides an effective method for the conservation of this endemic plant species.     

Plant regeneration via callus culture and subsequent in vitro flowering of Dendrobium huoshanense

A protocol for regenerating and subsequent in vitro flowering of an economical important and endangered medicinal orchid, Dendrobium huoshanense, was established mainly via indirect protocorm-like body (PLB) formation. A four-step method was developed to induce successful plant regeneration on 1/2 MS medium supplemented with suitable plant growth regulators (PGRs). Step 1 (callus induction): the root tip explants (1 cm long) were cultured at 1 mg l^?1 2,4-D + 1 mg l^?1 TDZ for 3 months. Step 2 (callus proliferation): the calli were subcultured with a 1-month interval at 1 mg l^?1 2,4-D + 1 mg l^?1 TDZ. Step 3 (PLB induction): the calli were cultured at 2 mg l^?1 NAA + 1 mg l^?1 BA for 2 months. Step 4 (plantlet conversion): the 2-month-old PLBs were cultured at 0.1 mg l^?1 IBA for 4 months. It took at least 6 months to produce well-rooted regenerated plantlets with an average of 3.2 roots and 3.6 leaves from the initial callus. The 6-month-old rooted plantlets were transferred onto PGR-free 1/2 MS medium for 6 months, and then potted with Sphagnum moss for acclimatization. After 2 month of culture, the survival rate was 100 %. The in vitro flowers were obtained on the 8-month-old plantlets at 1 mg l^?1 IBA, 5 mg l^?1 IBA and 0.1 mg l^?1 NAA, but the flowers showed a lack of the gynandrium. The abnormity was overcome by the aid of 5 mg l^?1 TDZ, and subsequently, the capsules formed without artificial pollination. This protocol provides the basis for further investigation on cell suspension, micropropagation, in vitro flowering and breeding programs in Dendrobium huoshanense.     

Enhanced biological denitrification of high concentration of nitrite with supplementary carbon source

Nitrite accumulates during biological denitrification processes when carbon sources are insufficient. Acetate, methanol, and ethanol were investigated as supplementary carbon sources in the nitrite denitrification process using biogranules. Without supplementary external electron donors (control), the biogranules degraded 200 mg l^?1 nitrite at a rate of 0.27 mg NO₂–N g^?1?VSS h^?1. Notably, 1,500 mg l^?1 acetate and 700 mg l^?1 methanol or ethanol enhanced denitrification rates for 200 mg l^?1 nitrite at 2.07, 1.20, and 1.60 mg NO₂–N g^?1?VSS h^?1, respectively; these rates were significantly higher than that of the control. The sodium dodecyl sulfate polyacrylamide gel electrophoresis of the nitrite reductase (NiR) enzyme identified three prominent bands with molecular weights of 37–41 kDa. A linear correlation existed between incremental denitrification rates and incremental activity of the NiR enzyme. The NiR enzyme activity was enhanced by the supplementary carbon sources, thereby increasing the nitrite denitrification rate. The capacity of supplementary carbon source on enhancing NiR enzyme activity follows: methanol?>?acetate?>?ethanol on molar basis or acetate?>?ethanol?>?methanol on an added weight basis.     

Biological versus geochemical control and environmental change drivers of the base metal budgets of a tropical montane forest in Ecuador during 15 years

To assess the susceptibility of the base metal budget of a remote tropical montane forest in Ecuador to environmental change, we determined the extent of biological control of base metal fluxes and explored the impact of atmospheric inputs and precipitation, considered as potential drivers of ecosystem change, on the base metal fluxes. We quantified all major base metal fluxes in a ca. 9.1 ha forested catchment from 1998 to 2013. Mean (±s.d.) annual flux to the soil via throughfall + stemflow + litterfall was 13800 ± 1500 mg m^?2 Ca, 19000 ± 1510 mg m^?2 K, 4690 ± 619 mg m^?2 Mg and 846 ± 592 mg m^?2 Na of which 22 ± 6, 45 ± 16, 39 ± 10 and 84 ± 33%, respectively, were leached to below the organic layer. The mineral soil retained 79–94% of this Ca, K and Mg, while Na was released. Weathering rates estimated with three different approaches ranged from not detected (ND) to 504 mg m^?2 year^?1 Ca, ND-1770 mg m^?2 year^?1 K, 287–597 mg m^?2 year^?1 Mg and 403–540 mg m^?2 year^?1 Na. The size of mainly biologically controlled aboveground fluxes of Ca, K and Mg was 1–2 orders of magnitude larger than that of mainly geochemically controlled fluxes (sorption to soil and weathering). The elemental catchment budgets (total deposition ? streamflow) were positive for Ca (574 ± 893 mg m^?2) and K (1330 ± 773 mg m^?2), negative for Na (?370 ± 1300 mg m^?2) and neutral for Mg (1.89 ± 304 mg m^?2). Our results demonstrate that biological processes controlled element retention for Ca, K and Mg in the biological part of the ecosystem. This was different for Na, which was mainly released by weathering from the study catchment, while the biological part of the ecosystem was Na-poor. The deposition of base metals was the strongest driver of their budgets suggesting that the base metal cycling of the study ecosystem is susceptible to changing deposition.