47 High-resolution ribosome profiling reveals translational selectivity in the mammalian blastocyst

Transcriptomic analyses of early mammalian embryos from multiple species have been comprehensively conducted in the last decade. However, mRNAs detected from overall transcriptomic profile of an embryo or a single cell do not necessarily represent their functional status, as there is a gap between the overall transcriptome and mRNAs that are actively translated. Ribosome profiling has been developed to infer the translational status of a specific mRNA species and thus analyse the genome-wide translatome. However, the broad application of ribosome profiling has been slowed by its complexity and the difficulty of adapting it to low-input samples such as embryos. In this study, we developed an ultra-low-input ribosome profiling protocol optimized for mammalian embryos and systematically analysed both polysome- and non-polysome-bound mRNA profiles of invitro-produced bovine blastocysts. Ten equal fractions were collected by means of sucrose density gradient and ultracentrifugation of lysates from 100 pooled blastocysts (n=2 pools), and subjected to RNA isolation and RNA sequencing. Our bioinformatics analyses of the mRNA profiles from each fraction along with the whole-transcriptome data revealed that compared with the overall transcriptome, there is a strong selection of mRNAs in the ribosome- and polysome-associated fractions, including transcriptional factors (e.g. POU5F1, ESRRB, AQP3, and APOA1) and genes involved in ribosome biogenesis, oxidative phosphorylation, and metabolic pathways, many of which are essential for the function of embryo implantation. We also identified novel epigenetic regulators selectively translated, including regulatory enzymes on histone modifications and RNA modifications (e.g. JMJD7, ALKBH4, ALKBH7, and METTL26). In addition, we confirmed the translation of the highly expressed, yet developmentally essential pathways in the blastocysts (e.g. Wnt and Notch signalling pathways). The selectively translated mRNAs were further validated by immunofluorescent staining at the protein level and cross-validated in both bovine and mouse blastocysts. Some of these genes show only modest expression in the overall transcriptome data. Their selective translation at the blastocyst stage is only being revealed by the ribosome fractions analyses, and their functions warrant future detailed investigations. In conclusion, this study reveals bona fide active translating mRNAs in the mammalian blastocyst. The low-input ribosome profiling protocol and the data presented here set an example and open future avenues for detailed ribosome fraction–based translatome analyses to reveal novel cellular/embryonic functional regulators beyond transcriptomic data.

GALNT10 promotes the proliferation and metastatic ability of gastric cancer and reduces 5-fluorouracil sensitivity by activating HOXD13

OBJECTIVE

To investigate the expression and potential mechanism of GALNT10 in gastric cancer (GC).

PATIENTS AND METHODS

A total of 60 cases of GC tissues, as well as normal tissues were collected. The total RNA of GC specimens and cells were extracted by TRIzol method and the level of GALNT10 was examined by quantitative real-time polymerase chain reaction (qRT-PCR). In addition, the relationship between GALNT10 and clinical parameters and prognosis of GC patients was analyzed. Subsequently, Lentivirus was used to construct GALNT10 knockdown GC cell lines, and cell counting kit-8 (CCK-8) and transwell assays were applied to analyze the influence of GALNT10 on GC cell function. Bioinformatics and Luciferase assay was used to evaluate the relationship between GALNT10 and HOXD13. Furthermore, 5-fluorouracil (5-Fu)-resistant cells were used to detect the relationship between GALNT10 and 5-Fu sensitivity of GC cells.

RESULTS

qRT-PCR results revealed that GALNT10 level was markedly increased in tissues, as well as cell lines of GC. Statistical analysis suggested that GALNT10 expression was in close relation with the incidence of lymph node and distant metastasis along with poor prognosis in GC patients, but not with other indicators. CCK-8 and transwell migration experiment results indicated that GALNT10 silencing can inhibit the proliferative and migration ability of GC cells. Western blot results displayed that the HOXD13 level was remarkably decreased after GALNT10 knocking down. In addition, Luciferase gene assay indicated that GALNT10 could bind to HOXD13. Further rescue experiments showed that HOXD13overexpression can synergistically reverse the inhibitory effect of GALNT10 knockdown on GC cell proliferative and migration ability, which further demonstrated that GALNT10 could promote GC cell metastasis ability and reduce the sensitivity to 5-Fu by regulating HOXD13.

CONCLUSIONS

GALNT10 could regulate the proliferative and migration ability of GC cells and reduce the sensitivity to 5-Fu by enhancing the expression of HOXD13. Therefore, GALNT10 was expected to be a new therapeutic target for diagnosis of 5-fluorouracil resistance in GC.

Computer-generated photorealistic hologram using ray-wavefront conversion based on the additive compressive light field approach

The conventional computer-generated hologram reconstructing photorealistic three-dimensional (3D) images based on ray-wavefront conversion has the disadvantage of spatio-angular resolution trade-off. In this Letter, we propose for the first time, to the best of our knowledge, a computer-generated photorealistic hologram without spatio-angular resolution trade-off based on the additive compressive light field (CLF) approach. The original light field is compressed into multiple layer images through numerical optimization based on the additive light field principle. Then, by independently calculating the wave propagation from each layer image to the hologram plane and adding them together, a CLF hologram is generated. Since the CLF information is presented through a holographic method, the advantage of high resolution in CLF is preserved while the limitation of the number of physically stacked layers (such as liquid crystal displays) is removed, leading to higher quality, larger depth of field, and higher brightness compared with a conventional CLF display. The proposed method is verified with a photorealistic optical experiment.

2 The landscape of accessible chromatin in bovine oocytes and early embryos

Chromatin reorganization governs gene expression regulation during pre-implantation development. However, the global chromatin landscape and its dynamics in this period remain unexplored in bovine. In this study, we constructed a genome-wide map of accessible chromatin in bovine oocytes and early embryos using an improved assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq). We analysed pools of 20 germinal vesicles or MII oocytes or 2-, 4-, 8-, 16-cell, morula, and blastocyst stage invitro-produced embryos. We conducted ATAC-seq on six pools for each stage and an additional four pools of invivo-derived morula and blastocysts and six replicates using individual Day 14 elongating embryos. We obtained ~110 million paired end reads uniquely mapped to the bovine reference genome for each stage. Hierarchical clustering, t-distributed stochastic neighbour embedding, and principal component analysis showed four distinct patterns for open chromatin status: (1) low accessibility in germinal vesicles and MII oocytes and in 2- and 4-cell embryos; (2) significantly elevated accessibility in 8-cell, 16-cell, and morula embryos; (3) less accessibility in blastocysts; and (4) extremely high accessibility in elongating embryos. This dynamic and sequential chromatin remodelling is consistent with transcription activation during the bovine minor embryonic genome activation from fertilization to 4-cell, major embryonic genome activation at 8-cell, first differentiation at blastocyst and drastic transcription initiation for embryo elongation. Genome-wide characteristics of accessible chromatin showed (1) accessible chromatin near the transcription start sites of active genes and CpG-rich promoters; (2) widespread accessible chromatin regions extensively overlapped with transposable elements; (3) distal peaks preferentially enriched for repeats including LINE, SINE, and LTR from 8-cell to morula embryos, especially for LTR, whereas enrichment in simple repeats were found from oocytes to 4-cell and in elongating embryos; and (4) highly stage-specific transcription factor motifs in distal peaks were unveiled. By integrating the maps of chromatin accessibility with bovine embryo transcriptomes and DNA methylomes, we found promoter accessibility and DNA methylation in bovine embryos correlated with both gene activities and CpG densities. Most importantly, we constructed the regulatory networks of stage-specific expressed genes and stage-specific activated genes with three omics datasets in bovine early embryos and revealed conserved and distinctive transcriptional regulatory networks between invivo- and invitro-derived embryos. This comprehensive analysis revealed critical features of the chromatin landscape and epigenetic reprogramming during bovine early embryo development.

31 Effect of vitrification on global gene expression dynamics of bovine elongating embryos

The ability to cryopreserve gametes and embryos has been a valuable tool for reproductive management in all mammalian species, especially livestock. Embryo vitrification involves exposure to high concentrations of cryoprotectants and osmotic stress during cooling and warming. These factors have to affect gene expression. The elongating embryo is a stage of embryo development that can be recovered noninvasively in the cow on day (D) 14 and represents a critical stage of development when many embryos die. In this study, we aimed to evaluate the effect of vitrification on the transcriptome dynamics of D14 embryos by RNA sequencing (RNA-seq). Invitro blastocyst-stage embryos were vitrified by exposure to dimethyl sulfoxide and ethylene glycol solution, followed by placing on Cryo Loks and plunging in liquid nitrogen. After warming, embryos were loaded into straws and transferred into eight synchronized recipients, four cows received nonvitrified embryos and four cows received vitrified embryos (20 embryos per cow). Embryo flushing yielded 12 nonvitrified and 9 vitrified viable D14 embryos. Whole embryos (six nonvitrified and two vitrified embryos) or isolated trophectoderm (TE; four nonvitrified and seven vitrified) were processed for RNA-seq. The Smart-sEqn 2 protocol was followed to prepare RNA-seq libraries. Sequencing reads were prefiltered and aligned to the bovine genome, and gene expression values were calculated as fragments per kilobase of transcript per million mapped reads. Genes were deemed differentially expressed between treatments if they showed a false discovery rate P-value<0.05 and fold-change >2. Ingenuity pathway analysis was used to reveal gene ontology and pathways. Expression of 927 genes was changed in D14 embryos as a result of vitrification, with 782 and 145 genes upregulated and downregulated, respectively. In TE, vitrification resulted in 4096 and 280 upregulated or downregulated genes, respectively. Several pathways were upregulated by vitrification in both whole embryos and TE, including epithelial adherens junctions, sirtuin signalling, germ cell-Sertoli cell junction, ATM signalling, nucleotide excision repair, and protein ubiquitination pathways. Downregulated pathways included EIF2 signalling, oxidative phosphorylation, mitochondrial dysfunction, regulation of eIF4 and p70S6K signalling, mammalian target of rapamycin signalling, sirtuin singling, and nucleotide excision repair pathways. In addition, we found 671 and 61 genes upregulated and downregulated in both vitrified whole embryos and TE. Mitochondrial dysfunction and oxidative phosphorylation signalling were upregulated, whereas epithelial adherens junction and sirtuin signalling were downregulated, suggesting mitochondrial function and energy production were impaired in TE after vitrification. Our analysis identified specific pathways and implicated specific genes affected by cryopreservation and potentially affecting embryo developmental competence.

Naringin targets Zeb1 to suppress osteosarcoma cell proliferation and metastasis

Naringin, a citrus bioflavonoid, has anti-inflammatory actions and cardio- and neuroprotective effects. In addition, naringin exhibits multiple antitumor actions in several cancer types, including osteosarcoma, the most common type of bone cancer. Here, we show that naringin inhibits proliferation and invasion and induces apoptosis in human osteosarcoma cells by inhibiting zinc finger E-box binding homeobox 1 (Zeb1), a transcriptional repressor of epithelial differentiation involved in tumor metastasis. Our expression analyses confirm that Zeb1 is highly expressed in osteosarcoma specimens and cell lines. The effects of naringin, which included downregulation of Cyclin D1, MMP2, and bcl-2, where reproduced by siRNA-mediated Zeb1 silencing, whereas Zeb1 overexpression increased proliferation, migration, and Cyclin D1, MMP2, and bcl-2 levels. In addition, naringin administration reduced tumor nodule formation and attenuated the expression of the above proteins in the livers of mice injected with MG63 osteosarcoma cells. Our study provides preclinical evidence for the potential therapeutic application of naringin in the treatment of osteosarcoma.

MicroRNA-506-3p inhibits osteosarcoma cell proliferation and metastasis by suppressing RAB3D expression

Osteosarcoma is an aggressive bone tumor primarily affecting children and adolescents. Its cause is not yet fully understood, and there is an urgent need for more effective treatment. In the present study we identified several miRNAs whose expression is altered in osteosarcoma compared to adjacent normal tissue. Moreover, expression levels of one of those miRNAs, miR-506-3p, correlated negatively with expression of RAB3D (a Ras-related protein). Suppression of miR-506-3p in osteosarcoma led to increased expression of RAB3D, which in turn led to increased CDK4 (cyclin-dependent kinase 4) and MMP9 (matrix metalloprotein 9) activities. Our results suggest that miR-506-3p acts as a tumor suppressor in osteosarcoma and that its downregulation leads to tumor cell proliferation and metastasis due to upregulation of RAB3D- and CDK4-mediated signaling. miR-506-3p thus appears be a potentially useful target for adjuvant therapy in osteosarcoma patients.

Resolution priority holographic stereogram based on integral imaging with enhanced depth range

Conventional holographic stereogram (HS) can be generated through fast Fourier transforming parallax images into hogels. Conventional HS uses multiple plane waves to reconstruct 3D images with low resolution and is similar to the principle of depth priority integral imaging (II). We proposed the concept of resolution priority HS for the first time, which is based on the principle of resolution priority II, by adding a quadratic phase term on the conventional Fourier transform. In the proposed resolution priority HS, the resolution of reconstructed 3D images is much better than conventional HS, but the depth range is limited. To enhance the depth range, a multi-plane technique was used to present multiple central depth planes simultaneously. The proposed resolution priority HS with high resolution and enhanced depth range was verified by both simulation and optical experiment.

Analysis of the influence of living environment and age on vaginal fungal microbiome in giant pandas (Ailuropoda melanoleuca) by high throughput sequencing

A recent study has described the normal vaginal bacterial community in giant pandas, but there is a lack of knowledge of the fungal community residing in the vagina of giant pandas. In order to comprehensively understand the vaginal fungal microbial diversity and abundance in giant pandas, high throughput sequencing was used to analyse the ITS1 region, based on thirteen samples taken from the pandas' vaginas, which were grouped by sampling points and age. The results showed that the most abundant phyla were Basidiomycota (73.37%), followed by Ascomycota (20.04%), Zygomycota (5.23%), Glomeromycota (0.014%) and Chytridiomycota (0.006%). At the genus level, Guehomyces (37.92%) was the most abundant, followed by Cladosporium (9.072%), Trichosporon (6.2%) and Mucor (4.97%). Furthermore, Candida only accounted for a low percentage of the vaginal fungal community. With the saturation of rarefaction curves and fungal diversity indices, the samples from Dujiangyan and Chungking Safari Park (DC group) showed a higher fungal species richness and diversity than other living environments. Shannon diversity indices showed significant difference between group WL (Wolong nature reserve) and DC (P < .05). Additionally, a higher diversity was found in ten to fifteen years old (Group 2) than other groups. Group 2 and Group 3 displayed significant differences in the diversities of their vaginal fungal communities (P < .05). These data that has been collected from this research will be helpful for further study to improve the reproductive status of giant pandas.

Curative efficacy of Kangfuxin solution in combination with mesalazine in treatment of ulcerative colitis: Effects on inflammatory factors and oxidative stress

AIM: To investigate the clinical effects of Kangfuxin solution in combination with oral mesalazine in the treatment of ulcerative colitis (UC) and its effects on inflammatory factors and serum superoxide dismutase (SOD), nitric oxide (NO), and lipid peroxidase (LPO).

METHODS: One hundred and sixty UC patients were equally divided into two groups: a control group and an observation group. The control group was treated with oral mesalazine alone, while the observation group was treated with oral mesalazine plus Kangfuxin solution. The curative efficacy, indices of inflammatory factors, and serum levels of SOD, NO and LPO were observed and compared.

RESULTS: The observation group had a total response rate of 96.2%, which was statistically higher than that in the control group (85.0%; P < 0.05). After treatment, tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and IL-8 were statistically lower than those in the control group (127.8 ng/mL ± 21.4 ng/mL vs 190.7 ng/mL ± 22.4 ng/mL, 81.7 ng/mL ± 11.3 ng/mL vs 125.6 ng/mL ± 10.7 ng/mL, 0.4 ng/mL ± 0.1 ng/mL vs 0.6 ng/mL ± 0.2 ng/mL, P < 0.05 for all). In comparison with the control group, the concentration of SOD was statistically higher (51.7 U/mL ± 3.9 U/mL vs 34.4 U/mL ± 3.2 U/mL, P < 0.05), and those of NO and LPO were statistically lower in the observation group (8.2 U/mL ± 1.8 U/mL vs 12.5 U/mL ± 2.1 U/mL, 5.8 mol/L ± 0.4 mol/L vs 6.5 mol/L ± 0.3 mol/L, P < 0.05).

CONCLUSION: Kangfuxin solution in combination with oral mesalazine is effective in the treatment of UC, and can alleviate inflammatory reaction and promote oxyradical scavenging capacity.

DVP parametric imaging for characterizing ovarian masses in contrast-enhanced ultrasound

AIM

To evaluate whether parametric imaging with contrast-enhanced ultrasound is an approach capable of for the differential diagnosis of ovarian masses.

MATERIALS AND METHODS

The authors analysed 50 cases of ovarian masses by routine ultrasound and contrast-enhanced ultrasound with a new dedicated parametric image processing software-Sonoliver. The angiogenesis and blood perfusion mode on a digital video recorder were recorded and the morphological characteristics of time-intensity curve (TIC) and dynamic vascular pattern (DVP) curve were subsequently described. The quantity factor, including time to peak (TTP), maximum intensity (IMAX), rise time, (RT), mean transit time (mTT), generated by Sonoliver software were compared in both histological gradings.

RESULTS

There were 24 cases (86%) displaying mainly hypo-enhanced with blue imaging in those with benign masses and 15 cases (68%) displaying mainly hyper-enhanced imaging with red in those with malignant masses. The difference was statistically significant (p < 0.05). DVP curves were unipolar below the baseline in 23 cases (82%) of benign masses and unipolar above the baseline in 15 cases (68%) of malignant masses. IMAX, TTP, and mTT were all significantly higher in those with malignant masses than those with benign ones (all p < 0.05), but, no statistical difference in the RT between the two groups was found (p > 0.05).

CONCLUSIONS

According to the results, DVP parametric imaging is a new approach capable of differential diagnoses of overian masses with contrast-enhanced ultrasound.

Launching plasmonic Bloch waves with excited dye molecules

In this paper, we will demonstrate that excited dye molecules can be used to launch the plasmonic Bloch waves (PBWs) propagating at multi-metal-dielectric interfaces. The properties of the PBWs, such as wavevectors, propagating bands, the interface and grating period effect, were characterized by a leakage radiation microscope. Theoretical simulations were also carried out to reveal the properties of the PBWs and were consistent with the experimental results. What is more, experimental results reveal an interesting phenomenon: the PBWs launched by the excited dye molecules present different optical behaviors from those launched by far-field laser beams through attenuated total reflection. The mechanism of this difference was analyzed based on the energy conversion between the optical near-field and far-field. Our work provides a new way to launch the PBWs. Further, the coupling between the dye molecules and PBWs also demonstrates a new method to manipulate the fluorescence emission from random to controllable.

Experimental determination of the ²⁴Mg I (3s3p)³P₂ lifetime

We present the first experimental determination of the electric-dipole forbidden (3s3p)³P₂→(3s²)¹S₀ (M2) transition rate in ²⁴Mg and compare to state-of-the-art theoretical predictions. Our measurement exploits a magnetic trap isolating the sample from perturbations and a magneto-optical trap as an amplifier converting each ³P₂→¹S₀ decay event into millions of photons readily detected. The transition rate is determined to be (4.87 ± 0.3)×10⁻⁴  s⁻¹ corresponding to a ³P₂ lifetime of 2050(-110)(+140) sec. This value is in agreement with recent theoretical predictions, and to our knowledge the longest lifetime ever determined in a laboratory environment.

Bimetallic chips for a surface plasmon resonance instrument

In this work we have replaced a commonly used Au film with an Au/Ag bimetallic film working as the sensing chip in the commercial surface plasmon resonance (SPR) instrument, Biacore 3000. The bimetallic chip gives out sharper SPR dip than that by the chip made of an Au film. The applicability and stability of the bimetallic chip on the Biacore 3000 are tested by real-time monitoring of biological coupling processes between sulfamethoxazole (SMX) and anti-SMX, which is useful in rapid detection of contaminations in food products. The bimetallic chip performs stably in 6 times' usage and regeneration. Our experiment is helpful to push the bimetallic film into real applications in commercial SPR instruments.

Excitation of surface plasmon polaritons guided mode by Rhodamine B molecules doped in a PMMA stripe

In this Letter we show the inclusion of Rhodamine B molecules inside a dielectric-loaded surface plasmon waveguide that enables for a precise determination of its optical characteristics. The principle relies on the coupling of the fluorescence emission of the dye to plasmonic waveguided modes allowed in of the structure. Using leakage radiation microscopy in real and reciprocal spaces, we measure the propagation constant of the mode and as well as its attenuation length.

Surface plasmon converging and diverging properties modulated by polymer refractive structures on metal films

Polymer refractive microstructures are fabricated on metallic thin films and employed to modulate surface plasmons (SPs) propagations in a refractive manner. SP waves converging with different focal lengths and diverging effects are realized by the refractive structures. Authors investigated the modulation effect on SP waves as a function of different thicknesses and different shapes of the polymer micro-structures based on the effective refractive index model, where imaging properties of the SPs are observed experimentally by detecting the leaky radiation intensity of the SPs.

A new iterative algorithm to reconstruct the refractive index

The latest developments in x-ray imaging are associated with techniques based on the phase contrast. However, the image reconstruction procedures demand significant improvements of the traditional methods, and/or new algorithms have to be introduced to take advantage of the high contrast and sensitivity of the new experimental techniques. In this letter, an improved iterative reconstruction algorithm based on the maximum likelihood expectation maximization technique is presented and discussed in order to reconstruct the distribution of the refractive index from data collected by an analyzer-based imaging setup. The technique considered probes the partial derivative of the refractive index with respect to an axis lying in the meridional plane and perpendicular to the propagation direction. Computer simulations confirm the reliability of the proposed algorithm. In addition, the comparison between an analytical reconstruction algorithm and the iterative method has been also discussed together with the convergent characteristic of this latter algorithm. Finally, we will show how the proposed algorithm may be applied to reconstruct the distribution of the refractive index of an epoxy cylinder containing small air bubbles of about 300 micro of diameter.

Comparison of two induction chemotherapy regimens in combination with radiotherapy in patients with advanced nasopharyngeal carcinoma

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Background: Prospective randomized trials failed to show any survival benefits associated with the use of induction chemotherapy in nasopharyngeal carcinoma (NPC). Although cisplatin-based regimens were commonly used in these trials, the impact of cisplatin dose was not clear. Methods: Individual patient data of two published phase III trials using different cisplatin-based induction chemotherapy regimens were pooled together for analysis. A total of 365 patients with stage II-IV NPC received either cisplatin & epirubicin (EP, n = 144) or cisplatin, bleomycin & fluorouracil (PBF, n = 221) followed by radiotherapy between September 1989 and July 1994. The mean total cisplatin dose received by patients ranged from 162 mg/m2 in EP group to 232 mg/m2 in PBF group. Median follow-up time was 59 months. Results: The response rates at the end of induction chemotherapy were 86% in PBF group and 84% in EP group. No significant differences in tumor control and survival were observed between the two groups. Five-year overall survival rates were 63% in PBF group and 62.5% in EP group. Five-year loco-regional failure-free rates were 74% in PBF group and 65% in EP group, the difference being not significant after adjusting for stage grouping. Conclusions: No significant difference in treatment outcome was observed in patients using different cisplatin-based induction chemotherapy. The absence of survival benefits in chemotherapy arms was probably not related to the dose-intensity of cisplatin used, and escalating the total cisplatin dose alone in induction chemotherapy is not likely to improve survival.

No significant financial relationships to disclose.

Application of waste activated bleaching earth containing rapeseed oil on riboflavin production in the culture of Ashbya gossypii

Waste activated bleaching earth (ABE) that contained 40% rapeseed oil and was discharged by an oil refinery plant, was used for riboflavin production in a culture of Ashbya gossypii. When 125 g/L waste ABE that contained 50 g/L rapeseed oil was added into the culture, the riboflavin concentration was 1.12 g/L, which was almost 1.6-fold as high as that of pure rapeseed oil. However, in waste ABE concentration higher than 125 g/L, the produced riboflavin concentration decreased, which was due to the difficulty in mixing due to the presence of a high amount of solid material in the culture. The surface of the waste ABE was smooth without a hitch, because of being covered with rapeseed oil. However, after the culture, the surface of the waste ABE seemed like that of new one, and the oil content was nearly zero grams per liter. The waste ABE, oily clay, and its black color gradually fade and yellow little by little, and finally the waste ABE changed to yellow powder. Of the riboflavin produced during the culture, 70% was adsorbed in the oil free waste ABE. With diluted alkali solution, extraction only two times yielded 90% recovery of riboflavin adsorbed in the waste ABE. The waste ABE containing waste vegetable oil was suitable for raw material for production of the value-added useful bioproducts, which might be a good model for reuse of the waste resource.

A novel system A isoform mediating Na+/neutral amino acid cotransport

A cDNA clone encoding a plasma membrane alanine-preferring transporter (SAT2) has been isolated from glutamatergic neurons in culture and represents the second member of the system A family of neutral amino acid transporters. SAT2 displays a widespread distribution and is expressed in most tissues, including heart, adrenal gland, skeletal muscle, stomach, fat, brain, spinal cord, colon, and lung, with lower levels detected in spleen. No signal is detected in liver or testis. In the central nervous system, SAT2 is expressed in neurons. SAT2 is significantly up-regulated during differentiation of cerebellar granule cells and is absent from astrocytes in primary culture. The functional properties of SAT2, examined using transfected fibroblasts and in cRNA-injected voltage-clamped Xenopus oocytes, show that small aliphatic neutral amino acids are preferred substrates and that transport is voltage- and Na(+)-dependent (1:1 stoichiometry), pH-sensitive, and inhibited by alpha-(methylamino)isobutyric acid (MeAIB), a specific inhibitor of system A. Kinetic analyses of alanine and MeAIB uptake by SAT2 are saturable, with Michaelis constants (K(m)) of 200-500 microm. In addition to its ubiquitous role as a substrate for oxidative metabolism and a major vehicle of nitrogen transport, SAT2 may provide alanine to function as the amino group donor to alpha-ketoglutarate to provide an alternative source for neurotransmitter synthesis in glutamatergic neurons.

Cloning and functional identification of a neuronal glutamine transporter

Glutamine is the preferred precursor for the neurotransmitter pool of glutamate, the major excitatory transmitter in the mammalian central nervous system. We have isolated a complementary DNA clone (designated GlnT) encoding a plasma membrane glutamine transporter from glutamatergic neurons in culture, and its properties have been examined using the T7 vaccinia system in fibroblasts. When GlnT is transfected into CV-1 cells, L-glutamine is the preferred substrate. Transport is Na(+)-dependent and inhibited by alpha-methylaminoisobutyric acid, a specific inhibitor of neutral amino acid transport system A. Kinetic analysis of glutamine uptake by GlnT is saturable, with a Michaelis constant (K(m)) of 489 +/- 88 microM at pH 7.4. Glutamine uptake mediated by GlnT is pH-sensitive with a 5-fold greater efficiency of uptake at pH 8.2 than at pH 6.6. Only the maximal velocity of transport increases without a significant change in K(m). The distribution of GlnT mRNA and protein in the central nervous system is widespread and is expressed on neurons that use glutamate as their neurotransmitter. In cultured cerebellar granule cells, GlnT is expressed only on neurons and is absent from astrocytes. GlnT expression increases concomitantly with the morphologic and functional differentiation of these cells in vitro, consistent with its role of supplying glutamatergic neurons with their neurotransmitter precursor. GlnT is the first member of the system A family of neutral amino acid transporters with 11 putative membrane-spanning domains and is a potential target to modulate presynaptic glutamatergic function.

Differential actions of neurotrophins on apoptosis mediated by the low affinity neurotrophin receptor p75NTR in immortalised neuronal cell lines

The low affinity neurotrophin receptor (p75NTR) mediates apoptosis of a number of neuronal and non-neuronal cells but the signals leading to the apoptosis remain obscure. To reveal the mechanism of p75NTR-mediated apoptosis, a neural cell line expressing human p75NTR was established. The human cDNA fragment encoding for p75NTR was PCR-amplified, cloned into the retrovirus expression vector pXT-1 and transfected into the rat cerebellum cell line R2. The expression of p75NTR in the R2 cell line was demonstrated by both Northern blotting analysis and immunocytochemistry. Serum withdrawal induced dramatic apoptosis in p75NTR-expressing R2 cells (R2L1) but not in pXT-1 transfected control R2 cells (R2P). Reverse transcription polymerase chain reaction (RT-PCR) revealed that these cell lines express trkA and trkB but not trkC. The apoptosis of R2L1 cells triggered by the serum deprivation for 48 h was completely prevented by neurotrophin-3 and the antibody to p75NTR but only partially prevented by the nerve growth factor and brain derived neurotrophic factor. We conclude that the p75NTR mediates apoptosis of R2L1 cells by its intrinsic receptor effects requiring an unbound status of this receptor and that the apoptosis is prevented by neurotrophins or the antibody to p75NTR through distinct mechanisms.

Fabrication of holographic microlenses using a deep UV lithographed zone plate

Holographic microlens arrays and elliptical zone plates are fabricated on holographic plates and photoresists by interference between the first- and second-order diffracted waves from an ion etched Fresnel zone plate, which is made by electron-beam scanning and deep UV lithography. This method of fabrication is simple, and a holographic lens with a large numerical aperture and short focal length is obtained. Experimental results of focusing and imaging by a lens array and an elliptical zone plate are given. Two methods of fabricating holographic zone plates for an IR or UV wavelength are also proposed.

Double exposure hologram of hyperbolic fringes and its use in the measurement of optical coherence

A hologram of hyperbolic fringes generated by double exposure is presented in this paper. The principle and experimental results of using it to measure optical coherence are given as well.