Exfiltration and infiltration effect on sewage flow and quality: a case study of Hue, Vietnam

Sewage generated in Southeast Asia is typically characterized by small per-capita flow and low concentration. This study investigated the impacts of exfiltration (leaking-out) and infiltration (leaking-in) on sewage flow and quality in Hue, Vietnam. Sewage flow and quality were continuously monitored at the sewer outlet of a residential drainage area for 68 and 82 days during dry and rainy seasons, respectively. Infiltration was estimated based on the least sewage flow before morning. Lithium tracer tests were conducted to estimate the exfiltration ratio. The results indicated that sewage of the target sewer was weaker than the typical weak-strength sewage even on no-rain days of the dry season. Monitoring of electrical conductivity indicated that rainfall persistently decreased the sewage concentration for a maximum duration of 228 h. The estimated infiltration accounted for 11% and 62% of the total sewage inflow to the sewer during dry and rainy seasons, respectively. The tracer test indicated that exfiltration ratios during the dry and rainy seasons were 65.6% and 24.0%, respectively. As a result of developing the water balance, only 23% of the water supplied to the area reached the sewer outlet in the dry season, while 123% flowed in the rainy season. These results demonstrate that exfiltration decreased the sewage flow in the dry season, while infiltration significantly increased the sewage flow and decreased the sewage concentration in the rainy season. To the best of our knowledge, this is the first study to quantify the impacts of infiltration and exfiltration on sewage in Southeast Asia

Substrate size-dependent conformational changes of bacterial pectin-binding protein crucial for chemotaxis and assimilation

Gram-negative Sphingomonas sp. strain A1 exhibits positive chemotaxis toward acidic polysaccharide pectin. SPH1118 has been identified as a pectin-binding protein involved in both pectin chemotaxis and assimilation. Here we show tertiary structures of SPH1118 with six different conformations as determined by X-ray crystallography. SPH1118 consisted of two domains with a large cleft between the domains and substrates bound to positively charged and aromatic residues in the cleft through hydrogen bond and stacking interactions. Substrate-free SPH1118 adopted three different conformations in the open form. On the other hand, the two domains were closed in substrate-bound form and the domain closure ratio was changed in response to the substrate size, suggesting that the conformational change upon binding to the substrate triggered the expression of pectin chemotaxis and assimilation. This study first clarified that the solute-binding protein with dual functions recognized the substrate through flexible conformational changes in response to the substrate size

Pectoralis Major and Serratus Anterior Muscle Flap for Diaphragmatic Reconstruction

We have reported a new reconstruction method using a pectoralis major and serratus anterior muscle flap for diaphragmatic defects after chondrosarcoma resection. The reconstruction of diaphragmatic defects is challenging. In diaphragmatic reconstruction with chest wall defects, strong chest wall reconstruction and diaphragmatic flexibility are important to avoid interference with respiration. The artificial material Gore-Tex is used as the first choice, but it has infection-, exposure-, and durability-related drawbacks. As an alternative method using artificial material, we have reported our new technique—diaphragmatic reconstruction using a reversed-combined pectoralis major and serratus anterior muscle flap

Polyunsaturated fatty acids-enriched lipid from reduced sugar alcohol mannitol by marine yeast Rhodosporidiobolus fluvialis Y2

Brown macroalgae is a promising marine biomass for the production of bioethanol and biodiesel fuels. Here we investigate the biochemical processes used by marine oleaginous yeast for assimilating the major carbohydrate found in brown macroalgae. Briefly, yeast Rhodosporidiobolus fluvialis strain Y2 was isolated from seawater and grown in minimal medium containing reduced sugar alcohol mannitol as the sole carbon source with a salinity comparable to seawater. Conditions limiting nitrogen were used to facilitate lipid synthesis. R. fluvialis Y2 yielded 55.1% (w/w) and 39.1% (w/w) of lipids, per dry cell weight, from mannitol in the absence and presence of salinity, respectively. Furthermore, mannitol, as a sugar source, led to an increase in the composition of polyunsaturated fatty acids, linoleic acid (C18:2) and linolenic acid (C18:3), compared to glucose. This suggests that oxidation of mannitol leads to the activation of NADH-dependent fatty acid desaturases in R. fluvialis Y2. Such fatty acid composition may contribute to the cold-flow properties of biodiesel fuels. Our results identified a salt-tolerant oleaginous yeast species with unique metabolic traits, demonstrating a key role as a decomposer in the global carbon cycle through marine ecosystems. This is the first study on mannitol-induced synthesis of lipids enriched with polyunsaturated fatty acids by marine yeast

Enhanced propagation of Granulicatella adiacens from human oral microbiota by hyaluronan

Host determinants for formation/composition of human oral microbiota remain to be clarified, although microorganisms entering the mouth cannot necessarily colonize the oral environment. Here we show that human oral-abundant bacteria degraded host glycosaminoglycans (GAGs) in saliva and gingiva, and certain bacteria significantly grew on hyaluronan (HA), a kind of GAGs. Microbial communities from teeth or gingiva of healthy donors assimilated HA. Metagenomic analysis of human oral microbiota under different carbon sources revealed HA-driven Granulicatella growth. HA-degrading bacterial strains independently isolated from teeth and gingiva were identified as Granulicatella adiacens producing extracellular 130 kDa polysaccharide lyase as a HA-degrading enzyme encoded in a peculiar GAG genetic cluster containing genes for isomerase KduI and dehydrogenase DhuD. These findings demonstrated that GAGs are one of the host determinants for formation/composition of oral microbiota not only for colonization but also for the adaptation to the host niche. Especially, HA enhanced the G. adiacens propagation

Total port-access lobectomy via a subcostal trans-diaphragmatic approach for lung cancer

Video-assisted thoracic surgery has been recognized as an acceptable technique for the treatment of early-stage lung cancer, with the potential advantage of lower postoperative pain than that experienced after open thoracotomy. However, the procedure cannot completely alleviate postoperative pain and paraesthesia and causes some degree of intercostal nerve damage. To minimize postoperative pain in video-assisted thoracic surgery, several new approaches have recently been reported. We describe the case of a 51-year old woman who successfully underwent total port-access, video-assisted thoracoscopic lobectomy for Stage IA lung cancer via the subcostal trans-diaphragmatic approach. Our Results demonstrate the feasibility and safety of this procedure, which offers the advantages of minimizing intercostal nerve damage and facilitating better handling of staplers. © 2012 The Author

Lipase-Catalyzed Synthesis of Unsaturated Acyl L-Ascorbates and Their Ability to Suppress the Autoxidation of Polyunsaturated Fatty Acids

ABSTRACT: L-Ascorbic acid and various polyunsaturated fatty acids (PUFA) were condensed at 55°C by the immobilized lipase Chirazyme L-2 in dry acetone to produce the unsaturated acyl ascorbates. The PUFA moieties of the products were much more resistant to autoxidation at 65°C and nearly 0% relative humidity than the corresponding unmodified PUFA. The effects of the molar ratio of ascorbic acid or linoleoyl ascorbate to linoleic acid on the autoxidation of linoleic acid were examined. The autoxidation of linoleic acid was effectively suppressed at molar ratios greater than or equal to 0.2 when either ascorbic acid or linoleoyl ascorbate was mixed with linoleic acid. The addition of lauroyl ascorbate, synthesized through the enzyme-catalyzed condensation of ascorbic acid and lauric acid in acetone, to docosahexaenoic acid also significantly suppressed the autoxidation of docosahexaenoic acid at molar ratios of ≥0.2. Paper no. J9826 in JAOCS 78, 823-826 (August 2001). KEY WORDS: Acyl ascorbate, L-ascorbic acid, autoxidation, condensation, immobilized lipase, polyunsaturated fatty acid. Much attention has been paid to the use of polyunsaturated fatty acids (PUFA) as components in foods (1). However, PUFA are susceptible to autoxidation (2,3), and the autoxidation causes deterioration of the foods. L-Ascorbic acid is a hydrophilic antioxidant with a strong reducing ability. The lipase-catalyzed synthesis of acyl ascorbate in a solid-phase system (4) or in an organic solvent (5-9) has been reported. However, its ability to suppress lipid autoxidation has not been reported. In a previous paper (10), we reported the synthesis of 6-O-eicosapentaenoyl L-ascorbate by the lipase-catalyzed condensation of eicosapentaenoic acid and L-ascorbic acid in acetone and compared its autoxidation process to that of the unmodified eicosapentaenoic acid. In the work described in this paper, some PUFA L-ascorbates were synthesized using an immobilized lipase from Candida antarctica, Chirazyme ® L-2, and their autoxidation processes were then observed. The PUFA used were linoleic, α-linolenic, γ-linolenic, arachidonic, and docosahexaenoic acids. The effect of the molar ratio of unmodified L-ascorbic acid or linoleoyl ascorbate to linoleic acid on the suppression of the autoxidation of linoleic acid was examined. We previously reported the lipase-catalyzed condensation of ascorbic acid with various medium-chain fatty acids having carbon numbers of 6, 8, 10, and 12 in acetonitrile (11). Therefore, the ability of lauroyl ascorbate to suppress the autoxidation of docosahexaenoic acid was also evaluated in the present work. EXPERIMENTAL PROCEDURES Materials. γ-Linolenic and docosahexaenoic acids were supplied by the Maruha Corporation (Tokyo, Japan), and their purities were both greater than 95% based on gas chromatographic (GC) analysis. L-Ascorbic acid, linoleic acid, acetone, and hexane were purchased from Nacalai Tesque (Kyoto, Japan). α-Linolenic, arachidonic, and lauric acids were purchased from Sigma Chemical (St. Louis, MO). Immobilized lipase from C. antarctica, Chirazyme ® L-2 c.-f. C2, was obtained from Roche Molecular Biochemicals (Mannheim, Germany). The enzyme is the same as Novozym ® 435 according to the manufacturer. Soybean oil was purchased from Wako Pure Chemical Industries (Osaka, Japan). Condensation reaction. Acetone was first dehydrated by adding 5 Å molecular sieves. The water content of the acetone was about 0.01% (vol/vol), and was determined for each experiment by a Karl-Fischer titration. L-Ascorbic acid (0.125 mmol) and a PUFA [linoleic acid (0.577 mmol)], γ-linolenic acid (0.600 mmol), arachidonic acid, (0.638 mmol), α-linolenic acid (0.611 mmol), and docosahexaenoic acid (0.648 mmol)] were weighed into an amber glass vial with a screw cap, and 200 mg of Chirazyme L-2 and 2.5 mL of dehydrated acetone were added to the vial. The headspace of the vial was filled with nitrogen, and the vial was tightly sealed. The vial was then immersed in a waterbath at 55°C with vigorous shaking to commence the condensation reaction. At appropriate intervals, 10 µL of the reaction mixture was taken and mixed with 50 µL of a 50 mM solution of toluene in high-performance liquid chromatography (HPLC) eluent [acetonitrile/tetrahydrofuran/0.1% (vol/vol) phosphoric acid (50:22:28 by vol) as the internal standard for the HPLC analysis and then with 40 µL of HPLC eluent. The analysis was carried out by HPLC with a YMC-Pack C8 column (4.6 mm × 250 mm; YMC Inc., Kyoto, Japan) and an ultraviolet (UV) detector (245 nm). The mixture (20 µL) was applied to the column and eluted with the eluent at 1.5 mL/min. The retention times o

Numbers of presynaptic Ca2+ channel clusters match those of functionally defined vesicular docking sites in single central synapses

Many central synapses contain a single presynaptic active zone and a single postsynaptic density. Vesicular release statistics at such “simple synapses” indicate that they contain a small complement of docking sites where vesicles repetitively dock and fuse. In this work, we investigate functional and morphological aspects of docking sites at simple synapses made between cerebellar parallel fibers and molecular layer interneurons. Using immunogold labeling of SDS-treated freeze-fracture replicas, we find that Cav2.1 channels form several clusters per active zone with about nine channels per cluster. The mean value and range of intersynaptic variation are similar for Cav2.1 cluster numbers and for functional estimates of docking-site numbers obtained from the maximum numbers of released vesicles per action potential. Both numbers grow in relation with synaptic size and decrease by a similar extent with age between 2 wk and 4 wk postnatal. Thus, the mean docking-site numbers were 3.15 at 2 wk (range: 1–10) and 2.03 at 4 wk (range: 1–4), whereas the mean numbers of Cav2.1 clusters were 2.84 at 2 wk (range: 1–8) and 2.37 at 4 wk (range: 1–5). These changes were accompanied by decreases of miniature current amplitude (from 93 pA to 56 pA), active-zone surface area (from 0.0427 μm2 to 0.0234 μm2), and initial success rate (from 0.609 to 0.353), indicating a tightening of synaptic transmission with development. Altogether, these results suggest a close correspondence between the number of functionally defined vesicular docking sites and that of clusters of voltage-gated calcium channels