First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Cymbidium sinense in China

Cymbidium sinense are among the most important commercial orchids cultivated in China for flower production. In April of 2010, a leaf spot was sporadically observed on C. sinense in fields located in Guangzhou, China. Symptoms first appeared as yellow to brown, irregular-shaped lesions on the leaf margin or tip. As the infection continued on the tissues, the spot expanded and became dark brown along the margins and developed gray brown centers. At later stages, numerous epidermal acervuli developed on the lesions and mucilaginous conidial masses appeared on the lesions under moist conditions. Ten samples from tissue along the margins of lesions were collected and surface sterilized by washing in 70% ethanol for 30 s, followed by washing in 1% sodium hypochlorite for 30 s, and rinsing in sterile distilled water. These samples were plated onto potato dextrose agar (PDA) and incubated at 25°C with a 12-h alternating light and dark cycle. After 5 days, fungal colonies that grew from the tissue were subcultured onto PDA and pure cultures were obtained using the single-spore method. The fungus was identified as Colletotrichum gloeosporioides based on typical cultural characteristics and conidial morphology (1). PDA cultures were white at first and subsequently became grayish white to gray and pink to reddish brown. Conidia were straight, one-celled, hyaline, oblong, or cylindrical, slightly curved with truncate base and rounded apex and measured 14.0 to 19.5 × 4.0 to 6.0 μm. Chlamydospores, sclerotia, and a teleomorph were not found. Genomic DNA was extracted from one isolate and the internal transcribed spacer (ITS) region of the ribosomal DNA (ITS1-5.8S-ITS2) was amplified using ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-CCTCCGCTTATTGATATGC-3') primers. The ITS region was further cloned and sequenced and showed 100% homology with many GenBank sequences (e.g., HQ333546.1) of C. gloeosporioides as the closest match. Pathogenicity tests were done by transferring one 4-mm-diameter disk of PDA that was colonized by the test isolates to wounds (4 × 4 mm) made with a needle in the leaves of 1-year-old C. sinense plants. Control plants received a sterile agar plug in wound. Ten inoculated plants were covered with plastic bags to maintain a high relative humidity and maintained in a greenhouse at 25 ± 2°C for 72 h. Five days after inoculation, no symptoms developed on the control plants. Foliar lesions closely resembled those observed in the field. C. gloeosporioides was reisolated consistently from symptomatic tissue collected from greenhouse experiments. To our knowledge, this is the first report of C. gloeosporioides causing anthracnose on C. sinense in China. Reference: (1) B. C. Sutton. Colletotrichum Biology, Pathology and Control. CAB International, Wallingford, UK, 1992.

Radiation dose reduction in temporal bone CT with iterative reconstruction technique

BACKGROUND AND PURPOSE

Iterative reconstruction of CT images is characterized by reduced image noise and may allow reduction in radiation exposure. We investigated the influence of an IRT technique on image quality and radiation dose savings when applied to temporal bone CT.

MATERIALS AND METHODS

Based on the typical image quality level of adult subjects using routine radiation dose and FBP, an exsomatized cadaveric head with CNR characteristics closest to the level of clinical subjects was identified. Cadaver acquisitions were performed at multiple levels of tube current exposure. Reconstructions were performed using FBP and IRT (iDose), with multiple iDose levels applied for each acquisition. Transverse and coronal reformations of all reconstructions were evaluated subjectively and objectively. Phantom tests were performed to validate the protocol optimizations with iDose, specifically the spatial resolution relative to routine dose acquisitions. Finally, the results of protocol optimization with iDose were clinically validated in 50 patients.

RESULTS

At the same radiation dose, the image CNR of iDose reconstructions was higher than that of FBP and progressively increased with higher iDose levels. The combination of 100 mAs/section and iDoseL5 was the lowest dose that met the requirements for diagnostic acceptability, with CNR slightly higher than our routine institution protocol of 200 mAs/section with FBP reconstruction. Spatial resolution characteristics were similar between FBP and iDose at all different strengths. The findings were consistent among the cadaver, phantom, and clinical acquisitions.

CONCLUSIONS

The iDose IRT can help reduce radiation dose of temporal bone CT by 50% relative to routine institution protocols with FBP, while maintaining diagnostic image quality.

Observation of electron-antineutrino disappearance at Daya Bay

The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ(13) with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GWth reactors were detected in six antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. With a 43,000 ton-GWth-day live-time exposure in 55 days, 10,416 (80,376) electron-antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to expected number of antineutrinos at the far hall is R=0.940±0.011(stat.)±0.004(syst.). A rate-only analysis finds sin(2)2θ(13)=0.092±0.016(stat.)±0.005(syst.) in a three-neutrino framework.

Pharmacokinetic, tissue distribution and excretion of ginsenoside-Rd in rodents

Ginsenoside-Rd (GS-Rd) is one of the major active components of Panax ginseng, and was shown to have the protective effects against several insults. However, we still lack some basic knowledge of GS-Rd, including its pharmacokinetic, tissue distribution and excretion in vivo in experimental animal, such as mice and rats. In this study, HPLC and radioactive tracer assays were performed to determine pharmacokinetic, tissue distribution and excretion of GS-Rd in rodents. After intravascular administration with 20, 50 or 150 mg/kg GS-Rd, the dynamic changes of GS-Rd concentrations in plasma were consistent with a two-compartment model while the concentration of ³H-labeled GS-Rd was rapidly reached the peak in plasma, and distributed to various tissues, among which the highest concentration was observed in the lung.

Octreotide is the favorable alternative for cisplatin resistance reversal of ovarian cancer in vitro and in nude mice in vivo

This study aimed to observe the effects of octreotide (OCT) on cisplatin resistance reversal of cancer cells in vitro and in nude mice in vivo. MTT method and flow cytometry were used to investigate the effect of cisplatin, OCT or the combination of these two compounds on the proliferation and apoptosis of SKOV3-DDP cells. The size and weight of xenograft tumors from the nude mice model were measured. Real-time PCR was used to detect the mRNA expression of SSTR2, MDR1, MRP2, GST-pi and EGFR in SKOV3/DDP cells following the different treatment. At the concentration of 2.5-20 g/ml, OCT significantly reduced IC50 (p < 0.05) and promoted apoptosis (p < 0.05) of SKOV3-DDP cells' response to cisplatin. Unchanged expression was found in SSTR2 on the SKOV3/DDP cell in vitro after OCT treatment, but increased expression in vivo (p < 0.05). OCT increased GST-pi expression (p < 0.05) and reduced MRP2 and EGFR expression (p < 0.05) in a dose-dependent manner. The similar results were obtained in mice in vivo experiment, except the reduced expression of GST-pi. It is suggested that OCT could inhibit ovarian cancer proliferation and promote apoptosis, via the cell surface SSTR2, and reverse cisplatin resistance through inhibition of MRP2, EGFR, and even GST-pi expressions.

Permanent genetic resources added to Molecular Ecology Resources Database 1 August 2011-30 September 2011

This article documents the addition of 299 microsatellite marker loci and nine pairs of single-nucleotide polymorphism (SNP) EPIC primers to the Molecular Ecology Resources (MER) Database. Loci were developed for the following species: Alosa pseudoharengus, Alosa aestivalis, Aphis spiraecola, Argopecten purpuratus, Coreoleuciscus splendidus, Garra gotyla, Hippodamia convergens, Linnaea borealis, Menippe mercenaria, Menippe adina, Parus major, Pinus densiflora, Portunus trituberculatus, Procontarinia mangiferae, Rhynchophorus ferrugineus, Schizothorax richardsonii, Scophthalmus rhombus, Tetraponera aethiops, Thaumetopoea pityocampa, Tuta absoluta and Ugni molinae. These loci were cross-tested on the following species: Barilius bendelisis, Chiromantes haematocheir, Eriocheir sinensis, Eucalyptus camaldulensis, Eucalyptus cladocalix, Eucalyptus globulus, Garra litaninsis vishwanath, Garra para lissorhynchus, Guindilla trinervis, Hemigrapsus sanguineus, Luma chequen. Guayaba, Myrceugenia colchagüensis, Myrceugenia correifolia, Myrceugenia exsucca, Parasesarma plicatum, Parus major, Portunus pelagicus, Psidium guayaba, Schizothorax richardsonii, Scophthalmus maximus, Tetraponera latifrons, Thaumetopoea bonjeani, Thaumetopoea ispartensis, Thaumetopoea libanotica, Thaumetopoea pinivora, Thaumetopoea pityocampa ena clade, Thaumetopoea solitaria, Thaumetopoea wilkinsoni and Tor putitora. This article also documents the addition of nine EPIC primer pairs for Euphaea decorata, Euphaea formosa, Euphaea ornata and Euphaea yayeyamana.

Recyclable magnetic photocatalysts of Fe2+/TiO2 hierarchical architecture with effective removal of Cr(VI) under UV light from water

We report the synthesis and photocatalytic removal of Cr(VI) from water of hierarchical micro/nanostructured Fe(2+)/TiO(2) tubes. The TiO(2) tubes fabricated by a facile solvothermal approach show a three-level hierarchical architecture assembled from dense nanosheets nearly vertically standing on the surface of TiO(2) microtube. The nanosheets with a thickness of about 20 nm are composed of numerous TiO(2) nanocrystals with size in the range of 15-20 nm. Ferrous ions are doped into the hierarchical architecture by a reduction route. The Fe(2+)/TiO(2) catalyst demonstrates an effective removal of Cr(VI) from water under UV light and the removal effectiveness reaches 99.3% at the initial Cr(VI) concentration of 10 mg L(-1). The ferrous ion in the catalyst serves not as the photo-electron trap but as an intermedium of a two-step reduction. The TiO(2) photoreduces the Fe(2+) ions to Fe atoms firstly, then the Fe atoms reduce the Cr(VI) to Cr(III), and the later is removed by adsorption. The hierarchical architecture of the catalyst serves as a reactor for the photocatalytic reaction of Cr(VI) ions and an effective absorbent for the removal of Cr(III) ions. The catalyst can be easily magnetically separated from the wastewater after photocatalytic reaction and recycled after acid treatment.

Experimental study and optimization of scan parameters that influence radiation dose in temporal bone high-resolution multidetector row CT

BACKGROUND AND PURPOSE

MDCT has some specific scan parameters that may systematically increase or decrease radiation dose to patients. This study explored the scan protocol parameters that impact radiation dose in temporal bone MDCT and determined the optimal scan parameters that balance radiation dose with diagnostic image quality.

MATERIALS AND METHODS

Using exsomatized cadaveric heads, traditional axial scanning, and helical scanning were performed with different detector collimations. Helical scans of the same scan region were then acquired by using the determined optimal detector collimation and various tube voltages, whereas other scan parameters remained fixed. Next, the scans were repeated by using various tube current-time products by using the determined optimal tube voltage. Last, with fixed tube current-time product, the scans were repeated with various pitches. All thin-section, helically acquired scans were reformatted to axial and coronal images with respect to the relevant scanning baseline. In each of the image volumes, the mean and SD HU values in regions of interest were measured in the central section of the internal auditory canal, and CNR values were calculated.

RESULTS

In agreement with theory, wider detector collimations such as 16 × 0.625 mm and 64 × 0.625 mm were associated with lower radiation doses than narrower collimations due to their lower overbeaming and higher geometric efficiency. In helical scanning, the detector collimation of 16 × 0.625 mm had higher image quality and the minimum DLP. Axial and coronal images acquired by using a 140-kVp tube voltage had significantly lower noise than scans acquired at 120 or 80 kVp with equivalent volume CT dose index. Diagnostic image quality was achieved when using a minimum tube current-time product of 120 mAs. Noise, CNR, and dose were jointly optimized with a pitch of 0.685.

CONCLUSIONS

Temporal bone CT scanning parameters may be optimized by following a systematic procedure that allows for the optimization of diagnostic image quality and the minimization of radiation dose. One such procedure for a particular 64-section MDCT scanner has been presented.

First Report of Myrothecium Leaf Spot of Hemionitis arifolia Caused by Myrothecium roridum in China

Hemionitis arifolia (Burm.) Moore. was grown commercially as an ornamental plant in China. In January 2010, a new foliar disease with typical leaf spot symptoms was observed on H. arifolia in Dongguan City, Guangdong Province. Approximately 10% of the plants in the Dongguan nursery were affected. Leaf spots were circular to subcircular, dark brown, with distinct concentric zones, and ranged from 10 to 20 mm in diameter. Lesions developed mostly on the lower leaves and black sporodochia with white mycelial tufts were produced mostly in older lesions under high humidity. Single-spore isolates from lesions plated on potato dextrose agar (PDA) produced white, floccose colonies and dark green-to-black sporodochia. Colonies reached 60 mm on PDA at 25°C after 14 days. Conidiophores branched repeatedly. Conidiogenous cells in whorls of two to six on ultimate branches were hyaline, cylindrical, and 13 to 20 × 1.2 to 1.8 μm. Conidia were hyaline, cylindrical, mostly with both rounded ends, occasionally one blunt end, and mean size was 6.1 (4.5 to 7.0) × 2.3 (1.8 to 3.0) μm. These characteristics were consistent with the descriptions of Myrothecium roridum Tode ex Fr. (2-4). The internal transcribed spacer regions including ITS1, ITS2, and the 5.8S rRNA of one isolate were PCR amplified and sequenced. A BLAST search in GenBank revealed highest similarity (99%) to M. roridum sequences from isolates collected from Germany (Accession Nos. AJ302001.1 and AJ301995.1). The M. roridum sequence from the Chinese isolate was submitted to GenBank (Accession No. JF343832). To confirm pathogenicity, five leaves on five H. arifolia plants were inoculated with 5-mm mycelial plugs from the periphery of 7-day-old cultures; sterile PDA plugs were used as the control treatment. Plants were covered with plastic bags and incubated in a growth chamber at 28°C. Necrotic lesions appeared 2 to 3 days after inoculation and the symptoms described above were observed after 7 days on all inoculated leaves, whereas sterile PDA plugs did not produce any leaf lesion. The pathogen was reisolated from the inoculated leaves and confirmed to be M. roridum on the basis of morphological characteristics. There are approximately 271 hosts of M. roridum (1), including many ornamental plants such as salvia (2) and garden hydrangea (3). To our knowledge, this is the first report of Myrothecium leaf spot on H. arifolia. Because the disease caused damage to the foliage and reduced the ornamental value of H. arifolia plants, control measures may need to be implemented for production of this species in ornamental nurseries. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrived from http://nt.ars-grin.gov/fungaldatabases/ , 6 February 2011. (2) J. A. Mangandi et al. Plant Dis. 91:772, 2007. (3) M. T. Mmbaga et al. Plant Dis. 94:1266, 2010. (4) M. Tulloch. Mycol. Pap. No. 130. CMI, Wallingford, UK, 1972.

Freshwater toxic cyanobacteria induced DNA damage in apple (Malus pumila), rape (Brassica napus) and rice (Oryza sativa)

Cyanobacteria in freshwater ecosystems can present a harmful effect on growth and development of plants through irrigation with contaminated water. In this study, the effects of microcystins (MCs)-containing cyanobacteria extract (CE) on DNA damage of apple, rape and rice were investigated to explore the phytotoxic mechanism of MCs through DNA fragmentation and RAPD analysis. Determination of DNA fragmentation by fluorescent dye DAPI showed that significant DNA damage was observed in rice seedlings after exposure to CE while DNA fragmentation in rape seedlings and apple cultures did not differ significantly between treatment and control groups. Qualitative characterization of genomic DNA fragmentation by agarose gel electrophoresis supported the quantitative determination using DAPI. The main changes in RAPD profiles of rape seedlings following exposure of lower doses of CE were variation in band intensity for the primers F03 and S01, while higher doses of CE caused loss of normal bands and appearance of new bands except band intensity changes. The data presented here demonstrate that DNA damage in plants occurs following exposure of microcystins, and the polymorphic RAPDs may be used as an investigation tool for environmental toxicology and as a useful biomarker for the detection of genotoxic effects of microcystins on plants.

Sb(2)O(3) nanobelt networks for excellent visible-light-range photodetectors

Excellent photoconductive properties have been found in Sb(2)O(3) nanobelts synthesized by a surfactant-assisted solvothermal method. Visible-light photodetectors have been designed from Sb(2)O(3) nanobelt networks using micrometer-wide gold wires as masks. Photodetectors show high sensitivity to visible light, high stability, and reproducibility. Fast response and decay times (<0.3 s) are comparable or even better than these parameters in many other metal oxide nanoscale photodetectors. The dominant mechanism of excellent photoconductivity is attributed to the barrier height modulations in the nanobelt-to-nanobelt contact regions. These results demonstrate that Sb(2)O(3) nanobelt networks can indeed serve as high-performance photodetectors in the visible light range.

Morphology controlled synthesis of spherical Bi2S3 flowers

The spherical Bi2S3 flowers have been fabricated by a facile environmentally friendly hydrothermal method. It was found that the flowers are composed of pure orthorhombic phase Bi2S3, the nanorods (nanowires) composed of the flowers grow radically from a center toward all directions to form a spherical structure, and the nanowires are single-crystalline and grow along the [001] direction. The reaction time, reaction temperature and thiourea play key roles for the formation of the flowers. The morphology of the Bi2S3 flowers (e.g., honeycombs, porous nanorods, nanorods, and nanowires) can be controlled simply by controlling the reaction time without varying experimental parameters or addition of other surfactant. The formation mechanism of Bi2S3 flowers is self-assembly and the intrinsic splitting character of the Bi2S3 structure. The spherical Bi2S3 flowers could be found potential applications in optical, catalysts and sensor devices.

Laryngeal juvenile xanthogranuloma: Imaging finding

Laryngeal juvenile xanthogranuloma is rare and there were only four cases have been reported previously in English literature. We report a case of isolated JXG of larynx in the superglottic region. The mass was well-defined and homogeneous hypoechoic in ultrasonography while presented indistinct boundary and soft tissue density in Computed Tomography images. Radiological findings are nonspecific but could help to understand the extent of the lesion. We suggest that JXG should be considered as differential diagnosis for laryngeal stridor. Laryngeal ultrasound is safe and reliable, which could be considered a useful diagnostic tool for supplementing laryngoscopy.

[Biodegradability of extracellular polymeric substances (EPS) produced by aerobic granules]

Aerobic granules were cultivated with synthetic wastewater and were added in the course of aerobic starvation. Results showed that EPS produced by aerobic granules was composed of 40% biodegradable and 60% nonbiodegradable EPS. Among these, only biodegradable EPS could be utilized by their producers, while nonbiodegradable EPS contributed to maintain the spatial structures of aerobic granules. EPS extracted from fresh aerobic granules was fed as the sole carbon source to their own producers and activated sludge and was utilized by them. The average biodegradation rate of activated sludge in terms of EPS was 1.5 times faster than that of aerobic granules. When EPS extracted from starved aerobic granules was fed as the sole carbon source to their own producers and activated sludge, it could not be utilized and could not be energy source.

[Morphological observation on the reproductive system of adult Schistosoma japonicum under confocal laser scanning microscopy]

BALB/c mice were infected with Schistosoma japonicum cercariae (40+/-2 per mouse) through abdominal skin. Mice were sacrificed after 35 days to acquire the adult worms which were then fixed, stained, clarified, dehydrated and mounted. The specimens were observed under the confocal laser scanning microscope. The overall morphology of the adult worms was displayed distinctly, especially the testicular lobes, seminal vesicle and genital pore of the male, reproductive system, and the ovary, vitelline glands, oviduct, vitelline duct, seminal receptacle, ootype, mehlis gland, uterus, genital pore and eggs of female reproductive system. The confocal laser scanning microscopy is an alternative method to research organs, tissues and cell structure of schistosome worm.

Regulation of Vibrio alginolyticus virulence by the LuxS quorum-sensing system

Quorum sensing (QS) is a bacterial intercommunication system that controls the expression of multiple genes in response to population density. The LuxS QS system regulates the expression of several virulence factors in a wide variety of pathogenic bacteria. LuxS has been characterized to be responsible for producing a type of autoinducer, AI-2, which stimulates the expression of the luciferase operon in Vibrio harveyi. Vibrio alginolyticus is established as an opportunistic pathogen of several marine animals, and its LuxS QS system remains undefined. To investigate the pathogenic role of luxS in V. alginolyticus, the luxS mutants of both the standard strain ATCC 33787 and a fish-clinical isolate MVP01, named MYJS and MYJM, respectively, were constructed. The mutation resulted in reduced lethality to Pagrus major. Intraperitoneal LD(50) of MYJS and MYJM increased by 15- and 93-fold, respectively. The two luxS mutants exhibited a lower growth rate and defective flagellar biosynthesis. They also showed a significant decrease in protease production and an increase in both extracellular polysaccharide production and biofilm development. The results suggest that the LuxS QS system plays an important role in regulating the expression of virulence factors in V. alginolyticus.

Comprehensive study of lead pollution in Shanghai by multiple techniques

Aerosol samples of PM10 particulates were examined with particle-induced X-ray emission (PIXE and micro-PIXE ), inductively coupled plasma-mass spectrometry, and X-ray absorption fine structures (XAFS) to investigate atmospheric Pb concentrations and its chemical species and to decide the source assignment. From the elemental analyses, lead concentrations were averaged at 369 and 237 ng.m-3 in aerosol samples of PM10 collected from 19 monitor sites in Shanghai in the winter of 2002 and 2003, respectively. The XAFS results show that major chemical forms of the lead particulates are probably PbCl2, PbSO4, and PbO. A calculation of isotope ratio and chemical mass balance of the PM10 samples revealed that the atmospheric lead particulates in Shanghai in the two periods were mainly from coal combustors, iron and steel plants, and automobile exhausts, with coal combustion dominating the lead pollution after the phasing out of leaded gasoline in 1997 in Shanghai.

Major histocompatibility complex class IIB allele polymorphism and its association with resistance/susceptibility to Vibrio anguillarum in Japanese flounder (Paralichthys olivaceus)

The full length of major histocompatibility complex (MHC) class IIB cDNA was cloned from a Chinese population of Paralichthys olivaceus by homology cloning and rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR). The MHC IIB genomic sequence is 1,864 bp long and consists of 34-bp 5'UTR, 741-bp open reading frame, 407-bp 3'UTR, 96-bp intron1, 392-bp intron2, 85-bp intron3, and 109-bp intron4. Phylogenetic analysis showed that the putative MHC class IIB amino acid of the Chinese P. olivaceus shared 28.3% to 85.4% identity with that of the reported MHC class IIB in other species. A significant association between MHC IIB polymorphism and disease resistance/susceptibility was found in Chinese P. olivaceus. Thirteen different MHC IIB alleles were identified among 411 clones from 84 individuals. Among the 280 (268) nucleotides, 32 (11.4%) nucleotide positions were variable. Most alleles such as alleles a, b, c, d, e, f, j, k, i, m were commonly found in both resistant and susceptible stock. Via chi2 test, allele d was significantly more prevalent in individuals from susceptible stock than from resistant stock, and their percentages were 23.80% and 7.14%, respectively. In addition, allele g occurred in 9 and allele h in 4 of 42 resistant individuals that were not present in the susceptible stock; their percentages were 21.4% and 9.52%, respectively. Although allele l was found only in 8 individuals from the susceptible stock, its percentage is 19.05%.

Distribution of sorbed phenanthrene and pyrene in different humic fractions of soils and importance of humin

Contributions of fulvic-humic acids (FA/HA) and humin (HM) to sorption of phenanthrene (PHE) and pyrene (PYR) in a soil were differentiated using a humic separation procedure after multi-concentration sorption experiments. It was found that the amount of solutes in FA/HA did not change significantly after 48 h, while that in HM increased continuously and slowly up to the end of the experimental period (720 h), indicating that HM was the main region for slow sorption. Based on the fitting results using Freundlich equation, it was found that nonlinearity of both solutes was greater in HM than in FA/HA, consistent with the sorption characteristics of individually extracted HA and HM in a separate experiment. The observed nonlinearity of the solute distribution was confirmed by using three other soil samples with organic carbon contents ranging from 0.7 to 7.9%. Distribution dynamics of PHE and PYR among various fractions were also discussed.

[Decolorization and isolation of recombinant hirudin expressed in the methylotrophic yeast Pichia pastoris]

Schemes for decolorization of broth and isolation of recombinant hirudin from the fermentation supernatants of recombinant yeast Pichia pastoris were developed to remove a great deal of non-desired proteins and coloring matters. Based on the stability of hirudin, heating is desirable to pre-treat the fermentation broth. Several different column chromatographies, including anion-exchange, cation-exchange, hydrokyapatite adsorption, hydrophobic interaction, gel filtration and their combination were investigated on the efficiencies of decolorization and isolation. Among these methods, the combination of cation-exchange and anion-exchange was found to be a success in both decolorization and isolation of hirudin.

Distribution and partitioning of polycyclic aromatic hydrocarbons (PAHs) in different size fractions in sediments from Boston Harbor, United States

The concentrations of 16 US EPA priority pollutant polycyclic aromatic hydrocarbons (PAHs) were analyzed in four size fractions (< 62, 62-125, 125-250, and > 250 microm) in three contaminated Boston Harbor sediments. Total PAH concentrations ranged from 7.3 to 358 microg/g dry wt. and varied largely among the different size fractions in these sediments. For all three sites, the highest PAH concentrations were associated with the large size (> 250 microm) fractions while the fine silt and clay fractions (< 62 microm) contained relatively low PAHs. Despite the great concentration differences, the composition of PAHs in the four size fractions of these sediments showed similar patterns dominated by PAHs with three or more rings. By examining the distribution patterns of selected alkyl homologs to parent compounds, the results indicate that the major PAHs contributing to the high contamination in the inner harbor sediments were from pyrogenic sources. A positive correlation between PAHs and sedimentary organic carbon exists for all size fractions in the sediments. Calculated organic carbon normalized partition coefficients (log K(oc)) for selected major PAHs indicate near-equilibrium partitioning of PAHs among the different size fractions despite their large concentration variations. Sedimentary organic matter associated with different size fractions was the controlling factor for the observed distribution differences of PAHs among the size fractions. Our results also suggest that sedimentary organic matter with different origins and maturities may have somewhat different PAH sorption characteristics. Particulate organic matter of charcoal, plant detritus and Capitella fecal pellets in the sediments appear to sorb PAHs more strongly than organic matter associated with clay minerals. The strong association of PAHs with these organic particles in sediments will have a great influence not only on their distribution but also on long-term environmental impact.

[Effects of glucose on growth, metabolism and EPO expression in recombinant CHO cell cultures]

The maximum viable cell density almost kept constant in the experimental range of initial glucose concentrations from 8.9 to 49.6 mmol/L in the batch cultures of recombinant CHO cells. The yield coefficient of lactate to glucose increased with the initial glucose concentrations from 8.9 up to 17.9 mmol/L, and then kept constant with above 17.9 mmol/L. There was little effect of glucose on glutamine metabolism. It was also demonstrated that the accumulative concentration of EPO increased with the increase of glucose concentration from 8.9 to 17.9 mmol/L, and decreased with its further increase from 17.9 to 49.6 mmol/L. It is showed that there is an optimum glucose concentration at which the EPO express of cultured recombinant CHO cells is on the peak.