Room-temperature quantum emission from interface excitons in mixed-dimensional heterostructures

The development of van der Waals heterostructures has introduced unconventional phenomena that emerge at atomically precise interfaces. For example, interlayer excitons in two-dimensional transition metal dichalcogenides show intriguing optical properties at low temperatures. Here we report on room-temperature observation of interface excitons in mixed-dimensional heterostructures consisting of two-dimensional tungsten diselenide and one-dimensional carbon nanotubes. Bright emission peaks originating from the interface are identified, spanning a broad energy range within the telecommunication wavelengths. The effect of band alignment is investigated by systematically varying the nanotube bandgap, and we assign the new peaks to interface excitons as they only appear in type-II heterostructures. Room-temperature localization of low-energy interface excitons is indicated by extended lifetimes as well as small excitation saturation powers, and photon correlation measurements confirm antibunching. With mixed-dimensional van der Waals heterostructures where band alignment can be engineered, new opportunities for quantum photonics are envisioned.

MiR-199a-5p suppresses proliferation and invasion of human laryngeal cancer cells

OBJECTIVE

To explore the roles of micro ribonucleic acid (miR)-199a-5p in the proliferation, apoptosis, invasion and metastasis of laryngeal cancer cells, and its molecular mechanisms.

PATIENTS AND METHODS

The expression of miR-199a-5p in 25 cases of laryngeal cancer tissues and paracancerous tissues was detected via quantitative real-time polymerase chain reaction (qRT-PCR). Its expression in TU212, TU686 and human epithelial type 2 (HEp-2) laryngeal cancer cell lines and normal nasopharyngeal epithelial cell line NP69 was also detected via qRT-PCR. HEp-2 cells were transiently transfected with miR-199a-5p mimic or miR-199a-5p inhibitor, and the expression of miR-199a-5p was verified using RT-PCR after transfection. The regulatory effects of miR-199a-5p on the proliferation, apoptosis, invasion and migration abilities of HEp-2 cells were observed through methyl thiazolyl tetrazolium (MTT) assay, flow cytometry, wound healing assay and transwell assay, respectively. Then, the mechanisms of miR-199a-5p in regulating Caspase-3 activity and epithelial-mesenchymal transition (EMT)-related proteins were further explored.

RESULTS

The qRT-PCR results revealed that miR-199a-5p was significantly lowly expressed in the laryngeal cancer tissues and tumor cell lines, and overexpression of miR-199a-5p substantially inhibited the proliferation of HEp-2 cells. According to the results of flow cytometry, overexpression of miR-199a-5p promoted the apoptosis of HEp-2 cells, whereas down-regulating miR-199a-5p suppressed their apoptosis. It was found that the activity of Caspase-3 was notably enhanced after overexpression of miR-199a-5p, which was evidently weakened after down-regulating miR-199a-5p. Wound healing assay and transwell assay results manifested that overexpressing miR-199a-5p weakened the invasion and migration abilities of HEp-2 cells, which were facilitated by down-regulating miR-199a-5p. Based on Western blotting results, miR-199a-5p regulated the expressions of E-cadherin, N-cadherin and vimentin. Overexpression of miR-199a-5p could inhibit EMT process, whereas suppressing miR-199a-5p could accelerate the process.

CONCLUSIONS

The expression of miR-199a-5p in laryngeal cancer tissues is substantially lower than that in the paracancerous tissues. MiR-199a-5p suppresses proliferation, invasion and migration in laryngeal cancer cell proliferation, while triggers cell apoptosis.

[Huge esophageal foreign bodies under rigid esophagoscope case for translation]

A 36 year old man with dysphagia and swallow painafter ingestion of a stone and unable to eat anything. The esophagus computer tomography showed that image consistent with a 24 mm×25 mm diameter circular object giant smooth stone located in the proximal esophagus. A clinical diagnosis based on these findings: foreign bodies in the esophagus.

[One case of laryngotracheal fungal disease]

Clinical manifestations: a female patient's hoarseness for more than 10 days. Video Laryngoscope: White toothpaste-like albuginea is visilable on the bilateral vocal cords and trachea about 2-3 ring. Pathology: Fungal bacterial mass.clinical diagnosis:Laryngeal fungal disease.

Label-free detection of fibrillar collagen deposition associated with vascular elements in glioblastoma multiforme by using multiphoton microscopy

Glioblastoma multiforme (GBM-WHO grade IV) is the most common and the most aggressive form of brain tumors in adults with the median survival of 10-12 months. The diagnostic detection of extracellular matrix (ECM) component in the tumour microenvironment is of prognostic value. In this paper, the fibrillar collagen deposition associated with vascular elements in GBM were investigated in the fresh specimens and unstained histological slices by using multiphoton microscopy (MPM) based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). Our study revealed the existence of fibrillar collagen deposition in the adventitia of remodelled large blood vessels and in glomeruloid vascular structures in GBM. The degree of fibrillar collagen deposition can be quantitatively evaluated by measuring the adventitial thickness of blood vessels or calculating the ratio of SHG pixel to the whole pixel of glomeruloid vascular structure in MPM images. These results indicated that MPM can not only be employed to perform a retrospective study in unstained histological slices but also has the potential to apply for in vivo brain imaging to understand correlations between malignancy of gliomas and fibrillar collagen deposition.

MicroRNA-449a inhibits cell growth in lung cancer and regulates long noncoding RNA nuclear enriched abundant transcript 1

OBJECTIVE

Lung cancer has become the primary cause of cancer-related death now. New therapies targeting the molecular regulatory machinery were required imperatively. MicroRNAs and long noncoding RNAs can respectively or cooperatively function as oncogenes or tumor suppressor genes in human cancers. The present study identified that miR-449a was down-regulated in tissue of human lung cancer. In this study, we aimed to investigate the function of miR-449a in NL9980 and L9981 lung carcinoma cells lines and the relationship with lncRNA nuclear enriched abundant transcript 1 (NEAT1).

MATERIALS AND METHODS

miR-449a was profiled in several lung carcinoma cell lines by quantitative reverse transcription-polymerase chain reaction RT-PCR. We analyzed the effects of miR-449a overexpression on proliferation, apoptosis and cell cycle in L9981 cells. The regulatory relationship between miR-449a and NEAT1 was predicted in silico and further studied by miR-449a inhibitor and mimics assay.

RESULTS

miR-449a was expressed in four cell lines, which we selected, however miR-449a was in high level in NL9980 and in low level in L9981 (P < 0.05). When the miR-449a was the overexpression in L9981 cells, the cell growth was suppressed, and the apoptosis cells were promoted compared with the control group (P < 0.05). The G1/G0 became longer and S, G2/M became shorter (P < 0.05) by miR-449a overexpression. Further study of the interaction between miR-449a and NEAT1 show that NEAT1 was up-regulated when cells were transfected with miR-449a inhibitor, and NEAT1 was down-regulated when cells transfected with miR-449a mimics.

CONCLUSIONS

Our data indicate that miR-449a may function as a suppressor of lung cancer, and affects the expression of NEAT1 in lung cancer cells.

Effect of Mobile Phone Radiation on Cardiovascular Development of Chick Embryo

The biological effects on cardiovascular development of chicken embryos were examined after radiation exposure using mobile phone (900 MHz; specific absorption rate˜1.07 W/kg) intermittently 3 h per day during incubation. Samples were selected by morphological and histological methods. The results showed the rate of embryonic mortality and cardiac deformity increased significantly in exposed group (P < 0.05). No any histological pathological changes were observed on Day 5-7 (D5-D7) of incubation. A higher distribution of lipid droplets was unexpectedly present in myocardial tissue from the exposure groups on D10-D13. Soon afterwards, myofilament disruption, atrioventricular valve focal necrosis, mitochondria vacuolization and atrial natriuretic peptide (ANP) decrease appeared on D15-D21 of incubation. Comet assay data showed the haemocyte mean tail in the exposed group was significantly larger than that of the control (P < 0.01). The arterial vascular wall of exposed group was thicker (P < 0.05) than that of the control on D13, which was reversed to normal in later stages. Our findings suggest that long-term exposure of MPR may induce myocardium pathological changes, DNA damage and increased mortality; however, there was little effect on vascular development.

Effects of AFP gene silencing on Survivin mRNA expression inhibition in HepG2 cells

We investigated the effects of alpha-fetoprotein (AFP) gene silencing on Survivin expression in HepG2 cells. Small interfering RNA technology was used to downregulate AFP expression in HepG2 cells. An enzyme-linked immunosorbent assay was used to measure AFP concentration in the supernatant before and after transfection. An MTT assay was used to detect cell proliferation activity before and after transfection. We performed flow cytometric analysis to detect the cell apoptosis rate, and reverse transcription-polymerase chain reaction to detect Survivin mRNA levels before and after transfection. Forty-eight hours after transfection, AFP concentration in the supernatant of the experimental group significantly decreased, hepatocellular carcinoma cell growth was inhibited by 43.1%, and the apoptosis rate increased by 24.3%. Survivin mRNA expression was reduced by 78.0% in HepG2 cells. These indicators in the control group and in the blank group did not change significantly. Silencing of AFP expression in HepG2 cells can effectively inhibit the growth of hepatoma cells and promote apoptosis, which may be useful for reducing intracellular Survivin mRNA levels.

Interaction of a contact resonance of microspheres with surface acoustic waves

We study the interaction of surface acoustic waves (SAWs) with a contact-based vibrational resonance of 1 μm silica microspheres forming a two-dimensional granular crystal adhered to a substrate. The laser-induced transient grating technique is used to excite SAWs and measure their dispersion. The measured dispersion curves exhibit "avoided crossing" behavior due to the hybridization of the SAWs with the microsphere resonance. We compare the measured dispersion curves with those predicted by our analytical model and find excellent agreement. The approach presented can be used to study the contact mechanics and adhesion of micro- and nanoparticles as well as the dynamics of microscale granular crystals.

Silicon nanowires with controlled sidewall profile and roughness fabricated by thin-film dewetting and metal-assisted chemical etching

This paper presents a non-lithographic approach to generate wafer-scale single crystal silicon nanowires (SiNWs) with controlled sidewall profile and surface morphology. The approach begins with silver (Ag) thin-film thermal dewetting, gold (Au) deposition and lift-off to generate a large-scale Au mesh on Si substrates. This is followed by metal-assisted chemical etching (MacEtch), where the Au mesh serves as a catalyst to produce arrays of smooth Si nanowires with tunable taper up to 13°. The mean diameter of the thus fabricated SiNWs can be controlled to range from 62 to 300 nm with standard deviations as small as 13.6 nm, and the areal coverage of the wire arrays can be up to 46%. Control of the mean wire diameter is achieved by controlling the pore diameter of the metallic mesh which is, in turn, controlled by adjusting the initial thin-film thickness and deposition rate. To control the wire surface morphology, a post-fabrication roughening step is added to the approach. This step uses Au nanoparticles and slow-rate MacEtch to produce rms surface roughness up to 3.6 nm.

Chromatin alterations in response to forced swimming underlie increased prodynorphin transcription

Antagonism of the kappa opioid receptor (KOR) has been reported to have anti-depressant-like properties. The dynorphin/KOR system is a crucial neurochemical substrate underlying the pathologies of addictive diseases, affective disorders and other disease states. However, the molecular underpinnings and neuroanatomical localization of the dysregulation of this system have not yet been fully elucidated. Utilizing the Porsolt Forced Swim Test (FST), an acute stressor commonly used as in rodent models measuring antidepressant efficacy, male Sprague-Dawley rats were subject to forced swimming for 15 min, treated 1h with vehicle or norbinaltorphimine (nor-BNI) (5 or 10mg/kg), and then 1 day later subject to FST for 5 min. In accordance with previous findings, nor-BNI dose dependently increased climbing time and reduced immobility. In comparison to control animals not exposed to FST, we observed a significant elevation in prodynorphin (pDyn) mRNA levels following FST using real-time optical polymerase chain reaction (PCR) in the caudate putamen but not in the nucleus accumbens, hypothalamus, amygdala, frontal cortex, or hippocampus. nor-BNI treatment did not affect pDyn mRNA levels in comparison to animals that received vehicle. The corresponding brain regions from the opposite hemisphere were analyzed for underlying chromatin modifications of the prodynorphin gene promoter region using chromatin immunoprecipitation with antibodies against specifically methylated histones H3K27Me2, H3K27Me3, H3K4Me2, and H3K4Me3, as well as CREB-1 and MeCP2. Significant alterations in proteins bound to DNA in the Cre-3, Cre-4, and Sp1 regions of the prodynorphin promoter were found in the caudate putamen of the FST saline-treated animals compared to control animals, with no changes observed in the hippocampus. Epigenetic changes resulting in elevated dynorphin levels specifically in the caudate putamen may in part underlie the enduring effects of stress.

The association between intensive glycemic control and vascular complications in type 2 diabetes mellitus: a meta-analysis

BACKGROUND AND AIM

In patients with type 2 diabetes mellitus, the relationship between lowering glycated hemoglobin (HbA(1c)) and macrovascular complications is not clear and therefore lowering the level of HbA(1c) is controversial.

METHODS AND RESULTS

We searched for all randomized controlled trials comparing the effects of intensive and standard glycemic control on vascular events in patients with type 2 diabetes mellitus. The primary endpoint was combined macrovascular complications, including cardiac events, stroke and peripheral vascular disease. Fixed and random effect models were used to analyze the results. Eight studies were included according to selection criteria. The results showed no benefits of intensive glycemic control on macrovascular and microvascular complications (P>0.1), but a higher rate of severe hypoglycemia (P<0.00001) in the intensive control group when the target HbA(1c) level was <7.0%. When the target HbA(1c) level was lowered to 7.0-7.9%, intensive glycemic control showed benefits on the reduction of microvascular events (P<0.05) without increasing the risk of severe hypoglycemia (P=0.74), but no influence on macrovascular complications (P>0.1).

CONCLUSION

The results of this analysis suggest that a target HbA(1c) level of 7.0-7.9% may be a better glycemic control target than that of <7.0% in patients with established type 2 diabetes mellitus.

Increased glycophorin A somatic cell variant frequency in arsenic-exposed patients of Guizhou, China

Exposure to arsenic through domestic burning arsenic-containing coal causes various tumors in a population of Guizhou, China. The glycophorin A (GPA) assay is a human mutation assay detecting somatic variation in erythrocytes expressing the MN blood type, and was used to assess genotoxicity of arsenic-exposed patients. Peripheral blood was collected from 18 adult healthy subjects and 40 arsenic-exposed patients in heparin-treated tubes. Erythrocytes were isolated, fixed in formalin and immuno-labeled with fluorescent antibodies against GPA, followed by flow cytometry analysis. Arsenic exposure increased the variant frequency (expressed as the number of variant red cells per 10(6) erythrocytes): NN, 3.7 in healthy subjects versus 21.2 in arsenic-exposed patients; N phi, 12.6 versus 33.1; MM, 13.1 versus 110; and M phi, 5.2 versus 20.3. The total GPA variant frequency was increased about five-fold (34.7 in healthy subjects versus 185 in arsenosis patients). Furthermore, the variant frequency was significantly higher in skin tumor-bearing patients: NN, 19.4 in arsenic-exposed non-tumor patients versus 31.5 in tumor-bearing patients; N phi, 29.5 versus 54.5; MM, 102 versus 159; M phi, 15.9 versus 45.1. Total GPA variant frequency in arsenic-exposed patients bearing skin tumors was significantly increased compared to patients without skin tumors (167 versus 290). The relationship between arsenic exposure history and GPA variant frequency was less evident. These data demonstrate that arsenic exposure is associated with mutations at the GPA locus, an effect exaggerated in patients bearing arsenic-induced skin tumors. The variant frequency of GPA could be a useful biomarker for arsenic exposure and arsenic carcinogenesis.

Terahertz Magnetic Response from Artificial Materials

We show that magnetic response at terahertz frequencies can be achieved in a planar structure composed of nonmagnetic conductive resonant elements. The effect is realized over a large bandwidth and can be tuned throughout the terahertz frequency regime by scaling the dimensions of the structure. We suggest that artificial magnetic structures, or hybrid structures that combine natural and artificial magnetic materials, can play a key role in terahertz devices.

Optimization of submerged culture requirements for the production of mycelial growth and exopolysaccharide by Cordyceps jiangxiensis JXPJ 0109

AIMS

The objective of the present study was to investigate the optimal culture requirements for mycelial growth and exopolysaccharide production by Cordyceps jiangxiensis JXPJ 0109 in submerged culture.

METHODS AND RESULTS

The effects of medium ingredients (i.e. carbon and nitrogen sources, and growth factor) and other culture requirements (i.e. initial pH, temperature, etc.) on the production of mycelia and exopolysaccharide were observed using a one-factor-at-a-time method. More suitable culture requirements for mycelial growth and exopolysaccharide production were proved to be maltose, glycerol, tryptone, soya bean steep powder, yeast extract, medium capacity 200 ml in a 500-ml flask, agitation rate 180 rev min(-1), seed age 4-8 days, inoculum size 2.5-7.5% (v/v), etc. The optimal temperatures and initial pHs for mycelial growth and exopolysaccharide production were at 26 degrees C and pH 5 and at 28 degrees C and pH 7, respectively, and corresponding optimal culture age were observed to be 8 and 10 days respectively. According to the primary results of the one-factor-at-a-time experiments, the optimal medium for the mycelial growth and exopolysaccharide production were obtained using an orthogonal layout method to optimize further. Herein the effects of medium ingredients on the mycelial growth of C. jiangxiensis JXPJ 0109 were in the order of yeast extract > tryptone > maltose > CaCl2 > glycerol > MgSO4 > KH2PO4 and the optimal concentration of each composition was 15 g maltose (food-grade), 10 g glycerol, 10 g tryptone, 10 g yeast extract, 1 g KH2PO4, 0.2 g MgSO4, and 0.5 g CaCl2 in 1 l of distilled water, while the order of effects of those components on exopolysaccharide production was yeast extract > maltose > tryptone > glycerol > KH2PO4 > CaCl2 > MgSO4, corresponding to the optimal concentration of medium was as follows: 20 g maltose (food-grade), 8 g glycerol, 5 g tryptone, 10 g yeast extract, 1 g KH2PO4, and 0.5 g CaCl2 in 1 l of distilled water.

CONCLUSIONS

Under the optimal culture requirements, the maximum exopolysaccharide production reached 3.5 g l(-1) after 10 days of fermentation, while the maximum production of mycelial growth achieved 14.5 g l(-1) after 8 days of fermentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report on the submerged culture requirements for mycelial growth and exopolysaccharide in C. jiangxiensis, and this two-step optimization strategy in this study can be widely applied to other microbial fermentation processes.

Interactions of phospholipid bilayer with chitosan: effect of molecular weight and pH

Chitosan has demonstrated its potentials as a gene carrier and a membrane perturbant for subsequent drug delivery to cells. However, there is currently a lack of experimental correlation between the physiochemical properties of chitosan and the resulting degree of lipid bilayer destabilization. In this study, the effect of pH and chitosan molecular weight on the interaction between chitosan and dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayer was examined with cross-polarization microscopy, differential scanning calorimetry (DSC), and Fourier transform- (FT-) Raman spectroscopy. Cross-polarized images showed that the direct hydration of the DPPC/chitosan mixture led to the formation of larger DPPC multilamellar vesicles (MLV), and pure chitosan also induced fusions of individual MLV. Under the influence of chitosan, the calorimetric enthalpy of DPPC was reduced in a concentration-dependent manner, and a new phase appeared at 28 degrees C during sample cooling. Even the lowest chitosan mole fraction of 0.04% reduced the cooperative unit of the DPPC bilayer by more than 70%. In addition, the electrostatic effect between chitosan and DPPC tuned the degree of membrane bilayer perturbation. Reduction of pH increased the number of protonated amines on the chitosan backbone and caused further disruption on the membrane organization. Mixing DPPC with chitosan in an organic medium before hydration enhanced the hydrophobic interactions between the two molecules and greatly reduced the cooperative unit among individual lipids during the main phase transition. The increase of chitosan molecular weight also affected the cooperativity in the thermotropic transition of DPPC bilayer. FT-Raman spectroscopy provided additional evidence that chitosan directly perturbed the organizations of the hydrophobic inner core of the DPPC bilayer.

Cbl-b, a RING-type E3 ubiquitin ligase, targets phosphatidylinositol 3-kinase for ubiquitination in T cells

Cbl-b is implicated in setting the threshold of T lymphocyte activation. In Cbl-b-deficient T cells, the activation of Vav, a guanine nucleotide exchange factor, is significantly enhanced. The molecular mechanism underlying Cbl-b-regulated Vav activation was unclear. Here it is shown that Cbl-b interacts with and induces ubiquitin conjugation to the p85 regulatory subunit of phosphatidylinositol 3-kinase, an upstream regulator of Vav. A functional RING finger of Cbl-b was essential for p85 ubiquitination. However, a loss of function mutation at the well-conserved amino-terminal variant src homology (SH) 2 domain of Cbl-b did not affect its ligase activity. A distal carboxyl-terminal proline-rich region in Cbl-b was mapped to contain the primary binding sequences for the SH3 domain of p85. Deletion of either the distal proline-rich region in Cbl-b or the SH3 domain of p85 severely reduced ubiquitin conjugation to p85. The data suggest a molecular link for Cbl-b-mediated negative regulation of Vav, with phosphatidylinositol 3-kinase as a direct target for Cbl-b E3 ubiquitin ligase.

Recognition and ubiquitination of Notch by Itch, a hect-type E3 ubiquitin ligase

Genetic studies identified Itch, which is a homologous to the E6-associated protein carboxyl terminus (Hect) domain-containing E3 ubiquitin-protein ligase that is disrupted in non-agouti lethal mice or Itchy mice. Itch-deficiency results in abnormal immune responses and constant itching in the skin. Here, Itch was shown to associate with Notch, a protein involved in cell fate decision in many mammalian cell types, including cells in the immune system. Itch binds to the N-terminal portion of the Notch intracellular domain via its WW domains and promotes ubiquitination of Notch through its Hect ubiquitin ligase domain. Thus, Itch may participate in the regulation of immune responses by modifying Notch-mediated signaling.

Oligonucleotide microarray based detection of repetitive sequence changes

Prior studies of oligonucleotide microarray-based mutational analysis have demonstrated excellent sensitivity and specificity except in circumstances where a frameshift mutation occurs in the context of a short repeated sequence. To further evaluate this circumstance, a series of nucleic acid samples having heterozygous mutations within repetitive BRCA1 sequence tracts was prepared and evaluated. These mutations included single nucleotide insertions and deletions in homopolymer runs, insertions and deletions of trinucleotide repeats, and duplications. Two-color comparative hybridization experiments were used wherein wild type reference and test targets are co-hybridized to microarrays designed to screen the entire BRCA1 coding sequence for all possible sequence changes. Mutations in simulated heterozygote samples were detected by observing relative losses of test target hybridization signal to select perfect match oligonucleotide probes. While heterozygous mutations could be readily distinguished above background noise in 9/19 cases, it was not possible to detect alterations in a poly dA/dT tract, small triplet repeat expansions, and a 10 bp direct repeat. Unexpectedly, samples containing (GAT)(3) triplet repeat expansions showed significantly higher affinity toward specific perfect match probes relative to their wild type counterparts. Therefore, markedly increased as well as decreased test sample hybridization to perfect match probes should be used to raise a suspicion of repetitive sequence changes.

Potent and stage-specific action of glutathione on the development of goat early embryos in vitro

The effect of glutathione (GSH) addition on the development of 1- or 2-cell goat early embryos in vitro was examined. Embryos were collected from superovulated Korean black goat (Capra hircus aegagrus) and cultured for 6 days in synthetic oviduct fluid medium supplemented with either bovine serum albumin (BSA) or serum. Without GSH addition, almost all embryos could not develop beyond 8- to 16-cell block. However, GSH addition greatly improved in vitro development of early embryos to blastocyst stage, and its action was highly dependent on the presence and source of proteins supplemented into the culture medium. Among the protein-supplemented cultures, GSH effect was most prominent in 10% FBS-supplemented culture, in which the proportion (91%) of blastocysts developed from early embryos was much higher than that of BSA- (42-64% depending on its content) or goat serum (GS)-supplemented cultures (21%), or even than that of somatic cell-supported co-culture (60%). As well as in terms of the morphological development, mean cell number of blastocysts (185 +/- 12) developed from FBS condition was significantly higher than that of blastocysts developed from any other culture conditions and moreover comparable to that of blastocysts developed in vivo (190 +/- 9). The viability of these blastocysts was finally confirmed by their term development (6/12) from embryo transfer. To delineate action time of GSH during embryo development, GSH was treated at 1-day intervals through 6-days culture periods excepting the last day. In the GSH-treated embryos at day 3 of culture, which corresponds to the time of in vitro 8- to 16-cell block stage, the proportion of blastocyst was markedly increased up to 77% of cultured embryos and conversely that of the arrested embryos was decreased to 7%. In the embryos treated later, however, their developmental potency decreased abruptly. Therefore, these results clearly demonstrated that GSH could greatly improve the in vitro development of goat early embryos by specifically acting on the 8- to 16-cell block stage during in vitro development, suggesting that GSH may be one of the important regulators on the development of goat embryos in vivo.

Production of biologically active human granulocyte colony stimulating factor in the milk of transgenic goat

We have developed a transgenic female goat harboring goat beta-casein promoter/human granulocyte colony stimulating factor (G-CSF) fusion gene by microinjection into fertilized one-cell goat zygotes. Human G-CSF was produced at levels of up to 50 microg/ml in transgenic goat milk. Its biological activity was equivalent to recombinant human G-CSF expressed from Chinese hamster ovary (CHO) cell when assayed using in vitro HL-60 cell proliferation. Human G-CSF from transgenic goat milk increased the total number of white blood cells in C57BL/6N mice with leucopenia induced by cyclophosphamide (CPA). The secreted human G-CSF was glycosylated although the degree of O-glycosylation was lower compared to CHO cell-derived human G-CSF.

SLP-76 and Vav function in separate, but overlapping pathways to augment interleukin-2 promoter activity

SLP-76 and Vav, two hematopoietic cell specific molecules, are critical for T cell development and activation. Following T cell antigen receptor stimulation, SLP-76 and Vav both undergo tyrosine phosphorylation and associate with each other via the SH2 domain of Vav and phosphorylated tyrosines of SLP-76. Furthermore, SLP-76 and Vav have a synergistic effect on interleukin (IL)-2 promoter activity in T cells. In this report, we show that two tyrosines, Tyr-113 and Tyr-128, of SLP-76 are required for its binding to Vav, both in vitro and in intact cells. Surprisingly, we find also that the interaction between SLP-76 and Vav is not required for their cooperation in augmenting IL-2 promoter activity, as the two molecules appear to function in different signaling pathways upstream of IL-2 gene expression. Overexpression of SLP-76 in the Jurkat T cell line potentiates the activities of both nuclear factor of activated T cells and AP-1 transcription factors. In contrast, overexpression of Vav leads to enhanced nuclear factor of activated T cells activity without affecting AP-1. Additionally, overexpression of Vav, but not SLP-76, augments CD28-induced IL-2 promoter activity. These findings suggest that the synergy between SLP-76 and Vav in regulating IL-2 gene expression reflects the cooperation between different signaling pathways.

Cubé resin insecticide: identification and biological activity of 29 rotenoid constituents

Cubé resin, the root extract from Lonchocarpus utilis and urucu, is an important insecticide, acaricide, and piscicide. The four major active ingredients are rotenone, deguelin, rotenolone, and tephrosin, totaling 77 wt %. As a commercial pesticide, the minor constituents are also of chemical interest and toxicological relevance. This study identifies 25 minor rotenoids in cubé resin "brittle" of which 12 are new compounds, the most unusual being 7'-chloro-5'-hydroxy-4',5'-dihydrodeguelin (the first chlororotenoid from a plant extract) and four isomers of 4',5'-dihydro-4', 5'-dihydroxytephrosin. Several of the minor rotenoids may be decomposition products from free radical processes during sample preparation, extraction with trichloroethylene, and processing the resin. Assays of the 29 rotenoids as inhibitors of NADH:ubiquinone oxidoreductase activity (primary target for toxicity) and phorbol ester-induced ornithine decarboxylase activity (indicator of cancer chemopreventive action) and for cytotoxicity establish similar structure-activity relationships in each system and the importance of the overall molecular conformation and the E-ring substituents.

New bioactive flavonoids and stilbenes in cubé resin insecticide

Fractionation of cubé resin from Lonchocarpus utilus and L. urucu roots led to the isolation and identification of 11 minor flavonoids and stilbenes containing the gem-dimethylpyran moiety or a dihydrodiol derivative thereof. The eight new compounds were as follows: the isoflavonoid cis-4'',5''-dihydro-4'',5' '-dihydroxylonchocarpusone (2); four (2S)-6-(gamma, gamma-dimethylallyl)-6'',6''-dimethylpyran[2'',3'':7, 8]flavanones with substituents of 5-hydroxy-3',4'-dimethoxy (3), 5, 3'-dihydroxy-4'-methoxy (4), 5,4'-dihydroxy-3'-methoxy (5), and 3', 4'-dimethoxy (6); and three 6'',6''-dimethylpyran[2'',3'':3', 4']stilbenes with 4-hydroxy-5'-methoxy (9), 3,5'-dimethoxy-4-hydroxy (10) and 3,4,5-trimethoxy (11) substitution patterns. Structure-activity relationships for inhibition of NADH:ubiquinone oxidoreductase activity (bovine heart electron transport particles) and phorbol ester-induced ornithine decarboxylase activity (cultured MCF-7 cells) generally parallel those for cytotoxicity (MCF-7 and Hepa 1clc7 cells).

The hematopoietic-specific adaptor protein gads functions in T-cell signaling via interactions with the SLP-76 and LAT adaptors

BACKGROUND

The adaptor protein Gads is a Grb2-related protein originally identified on the basis of its interaction with the tyrosine-phosphorylated form of the docking protein Shc. Gads protein expression is restricted to hematopoietic tissues and cell lines. Gads contains a Src homology 2 (SH2) domain, which has previously been shown to have a similar binding specificity to that of Grb2. Gads also possesses two SH3 domains, but these have a distinct binding specificity to those of Grb2, as Gads does not bind to known Grb2 SH3 domain targets. Here, we investigated whether Gads is involved in T-cell signaling.

RESULTS

We found that Gads is highly expressed in T cells and that the SLP-76 adaptor protein is a major Gads-associated protein in vivo. The constitutive interaction between Gads and SLP-76 was mediated by the carboxy-terminal SH3 domain of Gads and a 20 amino-acid proline-rich region in SLP-76. Gads also coimmunoprecipitated the tyrosine-phosphorylated form of the linker for activated T cells (LAT) adaptor protein following cross-linking of the T-cell receptor; this interaction was mediated by the Gads SH2 domain. Overexpression of Gads and SLP-76 resulted in a synergistic augmentation of T-cell signaling, as measured by activation of nuclear factor of activated T cells (NFAT), and this cooperation required a functional Gads SH2 domain.

CONCLUSIONS

These results demonstrate that Gads plays an important role in T-cell signaling via its association with SLP-76 and LAT. Gads may promote cross-talk between the LAT and SLP-76 signaling complexes, thereby coupling membrane-proximal events to downstream signaling pathways.

SLP-76 is a direct substrate of SHP-1 recruited to killer cell inhibitory receptors

Activation of immune system cells via antigen-, Fc-, or natural killer cell-triggering-receptor stimulation is aborted by co-engagement of inhibitory receptors. Negative signaling by killer cell inhibitory receptors and related receptors depends on the Src homology 2 (SH2)-containing protein tyrosine phosphatase SHP-1. Using a combination of direct binding and functional assays, we demonstrated that the SH2 domain-containing leukocyte protein 76 (SLP-76) is a specific target for dephosphorylation by SHP-1 in T cells and natural killer cells. Furthermore, we showed that tyrosine-phosphorylated SLP-76 is required for optimal activation of cytotoxic lymphocytes, suggesting that the targeted dephosphorylation of SLP-76 by SHP-1 is an important mechanism for the negative regulation of immune cell activation by inhibitory receptors.

[Separation and determination of eight plant hormones by reversed-phase high performance liquid chromatography]

In this paper, reversed-phase high performance liquid chromatographic technique was used for the separation and determination of eight plant hormones. Methanol-water-acetic acid system was chosen as the mobile phase. The effects of different separation conditions, such as the methanol and acetic acid concentrations in mobile phase, on the retention behaviours of eight plant hormones in this system were studied. The general trends in retention behaviours could be correlated to the methanol concentration in mobile phase. The experimental results showed that the optimum separation was achieved with following gradient elution condition: 0-3 minutes, 70% (water percentage in mobile phase), 3-13 minutes, 70%-20%, 13-48 minutes, 20%. Benzene was added to be as the internal standard. Under this experimental condition, the eight plant hormones could be separated completely and detected quantitatively at 260 nm within 16 minutes. The calibration curves for the eight compounds gave linearity over a wide range. The correlation coefficients of each components were r(ZT) = 0.9971, r(GAs) = 0.9999, r(K) = 0.9997, r(BA) = 0.9995, r(IAA) = 0.9998, r(IPA) = 0.9982, r(IBA) = 0.9995 and r(NAA) = 0.9995. The method is rapid, simple and efficient. It is a suitable method for the accurate determination of gibberellic acid (GA) and alpha-naphthaleneacetic acid (alpha-NAA) in products for agricultural use.

Adaptor proteins in lymphocyte antigen-receptor signaling

Adaptor molecules, proteins that possess no intrinsic enzymatic function, but which mediate protein-protein interactions, have a critical role in integrating signal transduction pathways following engagement of cell-surface receptors. Several newly described adaptor molecules have been shown to serve important functions in the regulation of signaling events initiated by lymphocyte antigen receptors. Understanding how these adaptor proteins function to modulate signaling cascades will provide important insights into the complex biology of lymphocyte activation.

Anticancer action of cubé insecticide: correlation for rotenoid constituents between inhibition of NADH:ubiquinone oxidoreductase and induced ornithine decarboxylase activities

Rotenone and rotenoid-containing botanicals, important insecticides and fish poisons, are reported to have anticancer activity in rats and mice. The toxic action of rotenone is attributed to inhibition of NADH:ubiquinone oxidoreductase activity and the purported cancer chemopreventive effect of deguelin analogs has been associated with inhibition of phorbol ester-induced ornithine decarboxylase (ODC) activity. This study defines a possible relationship between these two types of activity important in evaluating the toxicology of rotenoid pesticides and the suitability of the anticancer model. Fractionation of cubé resin (the commercial rotenoid pesticide) establishes that the activity in both assays is due primarily to rotenone (IC50 = 0.8-4 nM), secondarily to deguelin, and in small part to rotenolone and tephrosin. In addition, the potency of 29 rotenoids from cubé insecticide for inhibiting NADH:ubiquinone oxidoreductase in vitro assayed with bovine heart electron transport particles satisfactorily predicts their potency in vivo in the induced ODC assay using noncytotoxic rotenoid concentrations with cultured MCF-7 human breast cancer cells (r = 0.86). Clearly the molecular features of rotenoids essential for inhibiting NADH:ubiquinone oxidoreductase are similar to those for blocking ODC induction. This apparent correlation extends to 11 flavonoids and stilbenoids from cubé resin (r = 0.98) and genistein and resveratrol except for lower potency and less selectivity than the rotenoids relative to cytotoxicity. These findings on cubé insecticide constituents and our earlier study comparing rotenone and pyridaben miticide indicate that inhibition of NADH:ubiquinone oxidoreductase activity lowers the level of induced ODC activity leading to the antiproliferative effect and anticancer action.

Three domains of SLP-76 are required for its optimal function in a T cell line

We and others have shown that overexpression of SLP-76 augments TCR-stimulated IL-2 promoter activity in the Jurkat T cell line. In this report we investigate the signaling mechanisms through which SLP-76 mediates its effect on T cell activation. We show that overexpressed SLP-76 acts downstream of TCR-stimulated protein tyrosine kinases, but does not affect calcium signaling. Overexpression of SLP-76 does, however, augment TCR stimulation of both ERK (extracellular signal-regulated kinase) activity and a reporter construct driven by activating protein-1 binding sites. Structure/function analysis reveals that three distinct regions of SLP-76, each important for protein associations, are required for augmentation of TCR-induced nuclear factor-AT activity. These data suggest that SLP-76 functions as an adapter molecule that requires three unique domains to link proximal TCR signals in T cells.

Three domains of SLP-76 are required for its optimal function in a T cell line

We and others have shown that overexpression of SLP-76 augments TCR-stimulated IL-2 promoter activity in the Jurkat T cell line. In this report we investigate the signaling mechanisms through which SLP-76 mediates its effect on T cell activation. We show that overexpressed SLP-76 acts downstream of TCR-stimulated protein tyrosine kinases, but does not affect calcium signaling. Overexpression of SLP-76 does, however, augment TCR stimulation of both ERK (extracellular signal-regulated kinase) activity and a reporter construct driven by activating protein-1 binding sites. Structure/function analysis reveals that three distinct regions of SLP-76, each important for protein associations, are required for augmentation of TCR-induced nuclear factor-AT activity. These data suggest that SLP-76 functions as an adapter molecule that requires three unique domains to link proximal TCR signals in T cells.

Anomalous structure-activity relationships of 13-homo-13-oxarotenoids and 13-homo-13-oxadehyrorotenoids

Cube resin, used as an insecticide/miticide and piscicide, contains in decreasing amounts rotenone (1), deguelin (2), the 6a,12a-dehydro derivatives of rotenone (3) and deguelin (4), and the newly-discovered 13-homo-13-oxa-6a,12a-dehydro analogs [referred to as oxadehydrorotenone (5) and -deguelin (6)]. These six rotenoids were compared for potency as inhibitors of NADH:ubiquinone oxidoreductase activity and for organismal toxicity to mosquito larvae, goldfish, and mice and cytotoxicity in three mammalian cell lines (Hepa 1C1C7, MCF 7, and NB 41A3). Although rotenoids 3-6 contribute very little to the overall activity of cube resin, there were two surprising aspects to the structure-activity relationships. First, 1 was 7-15-fold more active than 2 in the cytotoxicity assays of 4-day duration but not in the other systems. This difference in cytotoxicity is not due to specificity at the oxidoreductase target but instead to more extensive cytochrome P450-dependent (piperonyl butoxide-sensitive) detoxification of 2 than of 1. Second, the observed potency increase on conversion of dehydrorotenone to either rotenone or oxadehydrorotenone suggests that combining both structural changes to form cis-13-homo-13-oxarotenone (8) might result in maximal activity. Accordingly, 5 was reduced with diisobutylaluminum hydride to the trans-isomer 7 and then epimerized with aqueous pyridine to the cis-isomer 8 of the same configuration as 1. Surprisingly, 8 was much less active than 1. This is rationalized on the basis of conformational changes in the B/C ring system and decreasing dihedral angle (determined by X-ray crystallography and/or molecular modeling) between the A and D rings that follow the potency order, i.e., rotenoids 1 and 2 > oxadehydrorotenoids 5 and 6 > trans- and cis-oxarotenoids 7 and 8 > dehydrorotenoids 3 and 4. Thus, the novel oxarotenoids and oxadehydrorotenoids help define the conformation optimal for NADH:ubiquinone oxidoreductase inhibition and toxicity.

An STS-based radiation hybrid map of the human genome

We have constructed a physical map of the human genome by using a panel of 83 whole genome radiation hybrids (the Stanford G3 panel) in conjunction with 10,478 sequence-tagged sites (STSs) derived from random genomic DNA sequences, previously mapped genetic markers, and expressed sequences. Of these STSs, 5049 are framework markers that fall into 1766 high-confidence bins. An additional 945 STSs are indistinguishable in their map location from one or more of the framework markers. These 5994 mapped STSs have an average spacing of 500 kb. An additional 4484 STSs are positioned with respect to the framework markers. Comparison of the orders of markers on this map with orders derived from independent meiotic and YAC STS-content maps indicates that the error rate in defining high-confidence bins is < 5%. Analysis of 322 random cDNAs indicates that the map covers the vast majority of the human genome. This STS-based radiation hybrid map of the human genome brings us one step closer to the goal of a physical map containing 30,000 unique ordered landmarks with an average marker spacing of 100 kb.

Tyrosines 113, 128, and 145 of SLP-76 are required for optimal augmentation of NFAT promoter activity

SLP-76 (SH2 domain leukocyte protein of 76 kDa) is a recently identified substrate of the TCR-stimulated protein tyrosine kinases that functions in the signal transduction cascade linking the TCR with IL-2 gene expression. In this report, we demonstrate that engagement of the TCR results in tyrosine phosphorylation of SLP-76 in its amino-terminal acidic region. Two tyrosines (Y113 and Y128) fall within an identical five amino-acid motif and are shown to be phosphorylated upon TCR ligation. Although mutation of either Y113 and Y128 has a minimal effect on SLP-76 function, mutation of both residues decreases significantly the ability of SLP-76 to promote T cell activation. A third tyrosine within the amino-terminal region (Y145) appears to be the most important for optimal SLP-76 function, as altering it alone to phenylalanine has a potent impact on SLP-76 augmentation of NFAT promoter activity.

Tyrosines 113, 128, and 145 of SLP-76 are required for optimal augmentation of NFAT promoter activity

SLP-76 (SH2 domain leukocyte protein of 76 kDa) is a recently identified substrate of the TCR-stimulated protein tyrosine kinases that functions in the signal transduction cascade linking the TCR with IL-2 gene expression. In this report, we demonstrate that engagement of the TCR results in tyrosine phosphorylation of SLP-76 in its amino-terminal acidic region. Two tyrosines (Y113 and Y128) fall within an identical five amino-acid motif and are shown to be phosphorylated upon TCR ligation. Although mutation of either Y113 and Y128 has a minimal effect on SLP-76 function, mutation of both residues decreases significantly the ability of SLP-76 to promote T cell activation. A third tyrosine within the amino-terminal region (Y145) appears to be the most important for optimal SLP-76 function, as altering it alone to phenylalanine has a potent impact on SLP-76 augmentation of NFAT promoter activity.

A gene map of the human genome

The human genome is thought to harbor 50,000 to 100,000 genes, of which about half have been sampled to date in the form of expressed sequence tags. An international consortium was organized to develop and map gene-based sequence tagged site markers on a set of two radiation hybrid panels and a yeast artificial chromosome library. More than 16,000 human genes have been mapped relative to a framework map that contains about 1000 polymorphic genetic markers. The gene map unifies the existing genetic and physical maps with the nucleotide and protein sequence databases in a fashion that should speed the discovery of genes underlying inherited human disease. The integrated resource is available through a site on the World Wide Web at http://www.ncbi.nlm.nih.gov/SCIENCE96/.

Analysis of chromosome 18 DNA markers in multiplex pedigrees with manic depression

Six pedigrees segregating manic-depressive illness (MDI) were analyzed for linkage to 21 highly polymorphic microsatellite DNA markers on chromosome 18. These markers span almost the entire length of the chromosome, and gaps between markers are less than 20 cM. In particular, we analyzed several markers localizing to the pericentromeric region of chromosome 18 which generated lod scores suggestive of linkage in an independent study. Lod score analysis was performed and results were examined by family. One region produced positive lod scores, though at 18q23 and not in the pericentromeric region. We additionally used two nonparametric methods because the true mode of transmission of MDI is unknown; results were again somewhat suggestive for markers in the region of 18q23 but not in the pericentromeric region.

The integral role of triacyl glycerols in the biosynthesis of the aldehydic sex pheromones of Manduca sexta (L)

In a gland located near the tip of their abdomens, Manduca sexta females produce a pheromone blend comprised of hexadecanal, (Z)-9-hexadecenal, (Z)- and (E)-11-hexadecenal, (E,Z)- and (E,E)-10,12-hexadecadienal, and (E,E,Z)- and (E,E,E)-10,12,14-hexadecatrienal. These aldehydes are produced and released by evaporation from the surface of the gland only during a discrete period of the night. They are not stored in the gland and are found there only in very small amounts, if at all, during other times of the photoperiod. However, fatty acyl analogues of the pheromone aldehydes are present in the gland in relatively large amounts, primarily as components of triacyl glycerols, continuously from eclosion of the adults until death. The unsaturated components are produced from hexadecanoate, which is desaturated to the monoenes. Then, (Z)-11-hexadecenoate is desaturated and isomerized to form the conjugated dienes and ultimately the conjugated trienes. The fatty acyl precursors of the pheromones, stored as components of triacyl glycerols, are converted into aldehydes by a process triggered by a pheromone biosynthesis activating neuropeptide (PBAN), produced in the brain-subesophageal complex. It is not yet clear whether this conversion involves direct reduction of the acyl groups to aldehydes or reduction to alcohols followed by oxidation to aldehydes.

Pheromone biosynthesis activating neuropeptides: functions and chemistry

Sex pheromones are critical for reproductive success in most species of Lepidoptera and their production is regulated by the action of pheromone biosynthesis activating neuropeptides (PBAN). These peptides, composed of 33-34 amino acids, have approximately 80% sequence homology and share the C-terminal sequence FSPRL-NH2, which has been shown to be the minimum sequence required for pheromonotropic activity. This pentamer is structurally similar to the active core (FXPRL-NH2, X = V, T or G) of the insect myotropic pyrokinins. Structure-activity studies have shown that all of the pyrokinins have various degrees of pheromonotropic activity and that some have a superagonistic effect. Peptides that only have sequence homology with PBAN in the C-terminal pentapeptide region, but that are pheromonotropic, also have been identified from months. These findings suggest that induction of pheromone biosynthesis may be regulated by more than one peptide, that PBAN may have a number of physiological functions, and that these peptides regulate induction of pheromone production in a variety of ways.

Search for a schizophrenia susceptibility gene on chromosome 18

Nine multiplex schizophrenia families were genotyped with 15 microsatellite markers mapping to the short and long arm of chromosome 18. Assuming either autosomal dominant or recessive inheritance evidence of linkage was not found. In addition, the non-parametric sib pair test did not reveal significant evidence of linkage.