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Anaerobic ponds are particularly effective in treating high-strength wastewater containing biodegradable solids as they achieve the dual purpose of particulate settlement and organic removal. Performance of an anaerobic pond system for treatment of starch wastewater containing high organic carbon, biodegradable starch particulate matter and cyanide was assessed under tropical climate conditions. Approximately 5000 m3/d of wastewater from starch industry was treated in a series of anaerobic ponds with a total area of 7.39 ha followed by facultative ponds with an area of 29.11 ha. Overall COD and TSS removal of over 90% and CN removal of 51% was observed. Active biomass obtained from the anaerobic ponds sediments and bulk liquid layer exhibited specific methanogenic activity of 20.7 and 11.3 ml CH4/g VSS d, respectively. The cyanide degradability of sludge at initial cyanide concentration of 10 and 20 mg/l were determined to be 0.43 and 0.84 mg CN-/g VSS d, respectively. A separate settling column experiment with starch wastewater revealed that a settling time of approximately 120 min is sufficient to remove 90-95% of the influent TSS. 相似文献
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Yuri T. Yamamoto Nirmala Rajbhandari Xiaohong Lin Ben A. Bergmann Yufuko Nishimura Anne-Marie Stomp 《In vitro cellular & developmental biology. Plant》2001,37(3):349-353
Summary We developed efficient genetic transformation protocols for two species of duckweed, Lemna gibba (G3) and Lemna minor (8627 and 8744), using Agrobacterium-mediated gene transfer. Partially differentiated nodules were co-cultivated with Agrobacterium tumefaciens harboring a binary vector containing β-glucuronidase and nptII expression cassettes. Transformed cells were selected and allowed to grow into nodules in the presence of kanamycin. Transgenic
duckweed fronds were regenerated from selected nodules. We demonstrated that transgenic duckweed could be regenerated within
3 mo. after Agrobacterium-mediated transformation of nodules. Furthermore, we developed a method for transforming L. minor 8627 in 6 wk. These transformation protocols will facilitate genetic engineering of duckweed, ideal plants for bioremediation
and large-scale industrial production of biomass and recombinant proteins. 相似文献
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Han Soo Yang Eunjin Kim Soojung Lee Hae Jeong Park Deborah S. Cooper Ira Rajbhandari Inyeong Choi 《The Journal of biological chemistry》2009,284(23):15970-15979
To understand the mechanism for ion transport through the sodium/bicarbonate transporter SLC4A4 (NBCe1), we examined amino acid residues, within transmembrane domains, that are conserved among electrogenic Na/HCO3 transporters but are substituted with residues at the corresponding site of all electroneutral Na/HCO3 transporters. Point mutants were constructed and expressed in Xenopus oocytes to assess function using two-electrode voltage clamp. Among the mutants, D555E (charge-conserved substitution of the aspartate at position 555 with a glutamate) produced decreasing HCO3− currents at more positive membrane voltages. Immunohistochemistry showed D555E protein expression in oocyte membranes. D555E induced Na/HCO3-dependent pH recovery from a CO2-induced acidification. Current-voltage relationships revealed that D555E produced an outwardly rectifying current in the nominally CO2/HCO3−-free solution that was abolished by Cl− removal from the bath. In the presence of CO2/HCO3−, however, the outward current produced by D555E decreased only slightly after Cl− removal. Starting from a Cl−-free condition, D555E produced dose-dependent outward currents in response to a series of chloride additions. The D555E-mediated chloride current decreased by 70% in the presence of CO2/HCO3−. The substitution of Asp555 with an asparagine also produced a Cl− current. Anion selectivity experiments revealed that D555E was broadly permissive to other anions including NO3−. Fluorescence measurements of chloride transport were done with human embryonic kidney HEK 293 cells expressing NBCe1 and D555E. A marked increase in chloride transport was detected in cells expressing D555E. We conclude that Asp555 plays a role in HCO3− selectivity.The electrogenic Na/HCO3 cotransporter NBCe1 (SLC4A4) is one of the SLC4A gene family members transporting HCO3− across the plasma membrane (1–3). NBCe1 plays a role in transepithelial HCO3− movement and pHi regulation in many tissues (4–6). NBCe1 is responsible for HCO3− reabsorption in the proximal tubules of the kidney (7). The proximal tubule cells reclaim HCO3− from the lumen through a series of reactions involving titration of HCO3− by H+ secretion via the apical Na/H exchanger, production of CO2, and regeneration of HCO3− and H+ in the tubule cells. HCO3− then moves to the interstitium via the basolateral NBCe1. The essential feature driving this basolateral Na+/HCO3− exit is the stoichiometry of 1:3 Na+:HCO3−, which makes the equilibrium potential for NBCe1 more positive than the resting membrane potential of the proximal tubule cells (8). The stoichiometry of 1Na+:1HCO3− or 1Na+:2HCO3− causes both ions to move into cells in other tissues such as pancreas, brain, and cardiovascular tissues (9, 10).Despite the importance of NBCe1 for basolateral HCO3− reabsorption in the proximal tubules, the mechanism of electrogenic Na/HCO3 transport via the transporter is not well understood. Ion movement depends on loading ions at their translocation or binding sites that likely reside within the membrane field at some distance from the bath solution (11). This implies that the transmembrane domains (TMs)2 of NBCe1 and amino acid residues within TMs play critical roles in ion transport.Sequence analysis of different SLC4A proteins shows similar hydropathy plots, predicting that these proteins share structural elements of transport function (12). Such similarities have facilitated structure/function studies to define molecular domains or motifs responsible for conferring Na/HCO3 transport of NBCe1. Abuladze et al. (13) performed a large scale mutagenesis on acidic and basic amino acids in non-TMs and found many residues affecting Na+-dependent base flux. McAlear et al. (14) identified amino acids in TM8 involving ion translocation. By a systematic approach of chimeric transporters between NBCe1 and the electroneutral Na/HCO3 cotransporter NBCn1 (SLC4A7) (15), we and our colleagues (16) demonstrated that electrogenic Na/HCO3 transport of NBCe1 requires interactions between the regions TM1–5 and TM6–13 of the protein. Zhu et al. (17) recently proposed TM1 as a domain lining the ion translocation pathway. On the other hand, Chang et al. (18) reported that the cytoplasmic N-terminal domain might contribute to HCO3− permeation.In the present study, we searched amino acid residues that are highly conserved among electrogenic Na/HCO3 transporters but not among electroneutral Na/HCO3 transporters and examined their role in electrogenic Na/HCO3 transport. Nine candidate residues in human renal NBCe1-A (5, 19) were selected and mutated by replacement with the amino acids at the corresponding sites of NBCn1. Mutant transporters were expressed in Xenopus oocytes and assessed via two-electrode voltage clamp. Our data show that Asp555 of NBCe1 plays an important role in HCO3− selectivity. 相似文献
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Microbial competition for limiting natural resources within a community is thought to be the selective force that promotes
biosynthesis of antimicrobial compounds The marine bacterium Streptomyces tenjimariensis produces the antibiotics istamycin A and B under select laboratory culture conditions; presumably these compounds serve an,
ecological role under natural conditions. Here we report results of a novel marine microbial competion experiment that examined
the impact of co-culture of marine bacteria on istamycin production by S. tenjimariensis. Twelve of the 53 bacterial species tested (i.e., 22.6%) induced Istamycin production; this antibiotic also inhibited growth
of the competitor colonies. These results suggest that marine bacterial metabolites, serve an ecological role in countering
competitive species. 相似文献
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Yuan Liu Travis Lear Olivia Iannone Sruti Shiva Catherine Corey Shristi Rajbhandari Jacob Jerome Bill B. Chen Rama K. Mallampalli 《The Journal of biological chemistry》2015,290(19):11843-11852
Fbxl7, a component of the Skp1·Cul1·F-box protein type ubiquitin E3 ligase, regulates mitotic cell cycle progression. Here we demonstrate that overexpression of Fbxl7 in lung epithelia decreases the protein abundance of survivin, a member of the inhibitor of apoptosis family. Fbxl7 mediates polyubiquitylation and proteasomal degradation of survivin by interacting with Glu-126 within its carboxyl-terminal α helix. Furthermore, both Lys-90 and Lys-91 within survivin serve as ubiquitin acceptor sites. Ectopically expressed Fbxl7 impairs mitochondrial function, whereas depletion of Fbxl7 protects mitochondria from actions of carbonyl cyanide m-chlorophenylhydrazone, an inhibitor of oxidative phosphorylation. Compared with wild-type survivin, cellular expression of a survivin mutant protein deficient in its ability to interact with Fbxl7 (E126A) and a ubiquitylation-resistant double point mutant (KK90RR/KK91RR) rescued mitochondria to a larger extent from damage induced by overexpression of Fbxl7. Therefore, these data suggest that the Skp1·Cul1·F-box protein complex subunit Fbxl7 modulates mitochondrial function by controlling the cellular abundance of survivin. The results raise opportunities for F-box protein targeting to preserve mitochondrial function. 相似文献
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Marcus M. Seldin Simon Koplev Prashant Rajbhandari Laurent Vergnes Gregory M. Rosenberg Yonghong Meng Calvin Pan Thuy M.N. Phuong Raffi Gharakhanian Nam Che Selina Mäkinen Diana M. Shih Mete Civelek Brian W. Parks Eric D. Kim Frode Norheim Karthickeyan Chella Krishnan Yehudit Hasin-Brumshtein Aldons J. Lusis 《Cell metabolism》2018,27(5):1138-1155.e6
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