242 POST-TRANSCRIPTIONAL REGULATION OF JY-1 mRNA ABUNDANCE DURING THE BOVINE OOCYTE-TO-EMBRYO TRANSITION

Oocyte-expressed genes play key roles in folliculogenesis and early embryonic development. The function of JY-1, a novel gene specifically expressed in bovine oocytes and early embryos, is unknown. We previously reported the expression pattern of JY-1 mRNA during meiotic maturation and early embryogenesis. The objective of this study was to elucidate the post-transcriptional regulation of JY-1 mRNA during oocyte maturation and early embryogenesis. For investigation of changes in length of JY-1 transcripts during the oocyte-to-embryo transition, total RNA isolated from germinal vesicle (GV) oocytes, metaphase II (MII) oocytes, and pronucleus (PN) stage embryos (300 oocytes/embryos per time point) was subjected to Northern blot analysis. Three major JY-1 transcripts of different length (approximately 1.8 kb, 1.2 kb, and 700 bp) were detected in GV oocytes. The size of all transcripts was decreased at MII, and PN stages by approximately 100 to 200 bp. The intermediate sized transcript was predominant at GV, MII and PN stages. Based on these initial qualitative results focused solely on changes in transcript size, we then conducted more detailed quantitative studies (using real-time PCR) focused on characterization of temporal changes in abundance of polyadenylated versus total JY-1 transcripts during early development. Total RNA samples isolated from GV and MII oocytes and from embryos at PN, 2-cell, 4-cell, 8-cell, 16-cell, morula, and blastocyst stage (n = 5 pools of 10 oocytes/embryos per time point) were divided into two equal aliquots. One aliquot was reverse transcribed into cDNA with oligo dT primers for quantification of polyadenylated transcripts and the other aliquot was transcribed with random hexamers (RH) for quantification of total transcripts. Amounts of polyadenylated JY-1 mRNA decreased during meiotic maturation (P < 0.0001), were increased (P < 0.05) at the PN and 4-cell stages relative to the MII stage, and then decreased to nearly undetectable levels after the 16-cell stage of embryo development. In contrast, amount of total JY-1 transcripts gradually decreased from PN through 16-cell stages to nearly undetectable levels thereafter. To confirm that the up-regulation of polyadenylated JY-1 mRNA in early developing embryos was not due to de novo transcription, alpha-amanitin was used to block the RNA polymerase II enzyme during the window of the first (24-13 h post-fertilization) or the second (33-14 h post-fertilization) embryonic cell cycle, and embryos at the 2-cell and 4-cell stages were collected (n = 4 pools of 10 embryos per time point). No significant changes were observed in abundance of JY-1 mRNA in control versus alpha-amanitin treated embryos. We conclude that JY-1 transcripts decrease in length during meiotic maturation and that polyadenylated JY-1 mRNAs detected in early developing embryos are oocyte-derived and not due to de novo transcription in early embryos. This work was supported by the Rackham Foundation and the Michigan Agricultural Experiment Station.

Enhancement of NF-kappaB activity by resveratrol in cytokine-exposed mesangial cells

Resveratrol, a natural polyphenolic phytoalexin, has been considered as a potential anti-inflammatory agent because of its suppressive effect on nuclear factor-kappaB (NF-kappaB). However, we recently found that treatment of glomerular mesangial cells with resveratrol significantly and dose-dependently enhanced NF-kappaB activation triggered by proinflammatory cytokines. This finding was evidenced by different reporter assays as well as by expression of an endogenous NF-kappaB-dependent gene, intercellular adhesion molecule-1. The NF-kappaB promoting effect of resveratrol was also observed in renal tubular LLCPK1 cells, but not in HepG2 hepatoma cells. In all cell types tested, treatment with resveratrol alone did not affect NF-kappaB activity. The enhanced activation of NF-kappaB by resveratrol progressed for at least 24 h and was accompanied by sustained down-regulation of an endogenous NF-kappaB inhibitor, IkappaBbeta, but not IkappaBalpha. Although expression of inducible nitric oxide synthase was suppressed by resveratrol, nitric oxide, a negative regulator of NF-kappaB, was not involved in the regulation of NF-kappaB by resveratrol. These data elucidated, for the first time, that resveratrol may enhance activation of NF-kappaB under certain circumstances.

Characterization and comparison of microsatellites derived from repeat-enriched libraries and expressed sequence tags

The construction of high-density linkage maps for use in identifying loci underlying important traits requires the development of large numbers of polymorphic genetic markers spanning the entire genome at regularly spaced intervals. As part of our efforts to develop markers for rainbow trout (Oncorhynchus mykiss), we performed a comparison of allelic variation between microsatellite markers developed from expressed sequence tag (EST) data and anonymous markers identified from repeat-enriched libraries constructed from genomic DNA. A subset of 70 markers (37 from EST databases and 33 from repeat enriched libraries) was characterized with respect to polymorphism information content (PIC), number of alleles, repeat number, locus duplication within the genome and ability to amplify in other salmonid species. Higher PIC was detected in dinucleotide microsatellites derived from ESTs than anonymous markers (72.7% vs. 54.0%). In contrast, dinucleotide repeat numbers were higher for anonymous microsatellites than for EST derived microsatellites (27.4 vs.18.1). A higher rate of cross-species amplification was observed for EST microsatellites. Approximately half of each marker type was duplicated within the genome. Unlike single-copy markers, amplification of duplicated microsatellites in other salmonids was not correlated to phylogenetic distance. Genomic microsatellites proved more useful than EST derived microsatellites in discriminating among the salmonids. In total, 428 microsatellite markers were developed in this study for mapping and population genetic studies in rainbow trout.

Changes in Chemical Composition of Alxa Bactrian Camel Milk During Lactation

Changes in chemical composition of Alxa bactrian camels reared in Inner Mongolia (China) during lactation were investigated. Colostrum and milk samples from 10 nomadic female camels in their first season of lactation were collected periodically from parturition until 90 d postpartum (PP). The average contents of gross composition were 14.23% protein, 4.44% lactose, 0.27% fat, 0.77% ash, and 20.16% total solids in colostrum at 2 h PP, and the respective mean values were 3.55, 4.24, 5.65, 0.87, and 14.31% for regular milk on d 90. A 15-fold increase was shown in fat content during the first 24 h, whereas a sharp decrease was shown during the first 12 h of lactation in protein, ash, and total solids contents. Variation in lactose content was small (4.24 to 4.71%) throughout the study period. Total N, nonprotein N, casein N, and whey protein N were found to be 2.23, 0.06, 0.86, and 1.31 g/100 mL for the colostrum at 2 h PP; and 0.56, 0.04, 0.45, and 0.07 g/100 mL for the milk at 90 d PP. Percentages of caseins increased steadily, whereas whey proteins declined gradually until 3 mo of lactation. Gas liquid chromatography analysis of milk fat showed that the content of even-numbered saturated fatty acids (C12:0-C18:0) in camel colostrum (2 h to 7 d PP) was lower than that of regular milk (15 to 90 d PP). The predominant saturated fatty acids were C14:0, C16:0, and C18:0, regardless of the stage of lactation. There was a considerable level of polyunsaturated fatty acids (mainly C18:1) in Alxa camel's milk fat. The levels of Ca, P, Na, K, and Cl were 222.58, 153.74, 65.0, 136.5, and 141.1 mg/100 g, respectively, at 2 h PP; the values of the minerals were 154.57, 116.82, 72.0, 191.0, and 152.0 mg/100 g, respectively, for the regular milk on d 90. The levels of vitamins A, C, E, B1, B2, B6, and D were 0.97, 29.60, 1.45, 0.12, 1.24, 0.54 mg/L, and 640 IU/L, respectively, in Alxa camel milk at 90 d PP. Vitamin A and C contents were higher and vitamins E and B1 were lower than those in colostrum. Sodium dodecyl sulfate-PAGE and densitometry results demonstrated that Alxa camel colostrum is rich in immunoglobulins, serum albumin, and 2 unknown fractions, which are reduced in amount (%) within 2 d of lactation. It seems that there is lack of beta-lactoglobulin in Alxa camel milk, whereas casein and -lactalbumin start at a low level and increase gradually until they reach their regular levels in the milk.

[Detection and treatment of early forms of Mycobacterium ulcerans infection in Ivory Coast]

Mycobacterium ulcerans infection (Mu) is an emerging public health problem. The cumulative number of cases in Ivory Coast was 10,382 in 1997. One of the key points of the Yamoussoukro "global initiative" in December 1997 involved detection and treatment of cases at the early-disease stage. The threefold purpose of this transversal study was to determine the frequency of nodular-stage Mu infection, to describe the features of the nodules, and to identify nodular features suitable for early screening use. Of the 93 nodules removed, 58.1% were due to Mu, indicating that the prevalence of nodular-stage Mu in Zoukougbeu, Ivory Coast was 9 per 1000 inhabitants. All Mu nodules were recent, caused pruritus, and displayed oedematous edges. The mean duration of disease was 23 months. In endemic areas, Mu infection should be suspected for any lesion that is of recent onset (< 5 year), shows visible elevation, has a diameter of 3 cm or more, or is mobile under the skin. Cold nodules that are adherent to the superficial skin layer and located on the limbs or firm cold nodules should also be considered as suspect. Excision of cold nodules caused by Mu is recommended. The wound heals within 4 weeks and no recurrences have been reported after 6-month follow-up.

Differentially expressed cellular genes following HBV: potential targets of anti-HBV drugs?

The aim of the study was to screen for cellular genes that are differentially expressed following hepatitis B virus (HBV) infection, in an attempt to identify potential targets of anti-HBV drugs. An oligonucleotide microarray containing 231 virus-infection-associated genes was prepared. Differential gene expression in HepG2.2.15 cells compared to control with HepG2 cells was analysed by this in-house microarray. The change in gene expression in HepG2.2.15 cells treated by lamivudine on days 4 and 8 after exposure was also studied. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to comfirm the differentially expressed genes induced by HBV and lamivudine. There were 31 upregulated and four downregulated genes in HepG2.2.15 cells compared with the HepG2 control cells. Eleven genes were consistently altered by lamivudine at both time points. Of the 31 genes that were upregulated in HepG2.2.15 cells, there were seven genes which were downregulated by lamivudine. Of the four downregulated genes, there was one gene which was upregulated by lamivudine. Of the differentially expressed genes induced by HBV and lamivudine, the expression of five genes was confirmed by semi-quantitative RT-PCR. These results shed new light on the effects of HBV and lamivudine on cellular gene expression. Differentially expressed genes induced by HBV and lamivudine could potentially become new anti-HBV drug targets in novel therapies.

Multi-frequency and multiple phase-shift sinusoidal fringe projection for 3D profilometry

In this paper, we report on a laser fringe projection set-up, which can generate fringe patterns with multiple frequencies and phase shifts. Stationary fringe patterns with sinusoidal intensity distributions are produced by the interference of two laser beams, which are frequency modulated by a pair of acousto-optic modulators (AOMs). The AOMs are driven by two RF signals with the same frequency but a phase delay between them. By changing the RF frequency and the phase delay, the fringe spatial frequency and phase shift can be electronically controlled, which allows high-speed switching from one frequency or phase to another thus makes a dynamic 3D profiling possible.

Application of electrospray ionization mass spectrometry in rapid typing of fengycin homologues produced by Bacillus subtilis

AIMS

To rapidly type the fengycin homologues produced by Bacillus subtilis strains with electrospray ionization/collision-induced dissociation (ESI/CID) mass spectrometry.

METHODS AND RESULTS

Fengycin homologues produced by Bacillus subtilis JA were analysed. When each homologue was subjected to ESI/CID analysis, ions representing characteristic fragmentations were detected. These ions can help to identify the homologues; even homologues of the same nominal mass can be discriminated by their ESI/CID spectra. Based on the CID results, fengycin homologues can be correctly assigned.

CONCLUSIONS AND SIGNIFICANCE OF THIS STUDY

ESI/CID leads to rapid detection and structural characterization of fengycin homologues or lipopeptides with similar properties. It will be very useful in studying the regulatory expression of these peptides.

Homology Modeling of Lanosterol 14α-Demethylase ofCandida albicansandAspergillus fumigatusand Insights into the Enzyme-Substrate Interactions

The crystal structure of 14alpha-sterol demethylase from Mycobacterium tuberculosis (MT_14DM) provides a good template for modeling the three dimensional structure of lanosterol 14alpha-demethylase, which is the target of azole antifungal agents. Homologous 3D models of lanosterol 14alpha-demethylase from Candida albicans (CA_14DM) and Aspergillus fumigatus (AF_14DM) were built on the basis of the crystal coordinates of MT_14DM in complex with 4-phenylimidazole and fluconazole. The reliability of the two models was assessed by Ramachandran plots, Profile-3D analysis, and by analyzing the consistency of the two models with the experimental data on the P450(14DM). The overall structures of the resulting CA_14DM model and AF_14DM model are similar to those of the template structures. The two models remain the core structure characteristic for cytochrome P450s and most of the insertions and deletions expose the molecular surface. The structurally and functionally important residues such as the heme binding residues, the residues lining the substrate access channel, and residues in active site were identified from the model. To explore the binding mode of the substrate with the two models, 24(28)-methylene-24,25-dihydrolanosterol was docked into the active site of the two models and hydrophobic interaction and hydrogen-bonding were found to play an important role in substrate recognition and orientation. These results provided a basis for experiments to probe structure-function relationships in the P450(14DM). Although CA_14DM and AF_14DM shared similar core structural character, the active site of the two models were quite different, thus allowing the rational design of specific inhibitors to the target enzyme and the discovery of novel antifungal agents with broad spectrum.

Mutation of Gluconobacter oxydans and Bacillus megaterium in a two-step process of l-ascorbic acid manufacture by ion beam

AIM

To increase the transformation rate of l-sorbose to 2-keto-l-gulonic (2-KLG) acid in a two-step process of l-ascrobic acid manufacture by ion beam.

METHODS AND RESULTS

Gluconobacter oxydans (GO29) and Bacillus megaterium (BM80) were used in the present study. Ion implantation was carried out with the heavy ion implantation facility at the institute of Plasma Physics in China. 2-KLG in whole culture broth was determined by iodometry. Mutants were screened by single-colony isolation and 2-KLG accumulation in broth. GO29 and BM80 were implanted by either hydrogen ions (H(+)) or nitrogen ions (N(+)) with various doses, respectively. The average transformation rate of GM112-302 bred by ion beam in Gram-molecule was increased from 79.3 to 94.5% after eight passages in shaking flasks. Furthermore, in 180-ton fermentors in Jiangsu Jiangshan Pharmaceutical Co. Ltd, the transformation rate was stable at 92.0%, indicating a producer could get 0.99 kg of gulonic acid from 1.0 kg of sorbose.

CONCLUSION

Ion beam as a new mutation source had potential advantages in breeding. Comparing with original mixture GO29 and BM80, GM112-302 is more efficient in accumulating 2-KLG, especially at the later phase.

SIGNIFICANCE AND IMPACT OF THE STUDY

GM112-302 bred by ion beam implantation dramatically increased the transformation rate by 19.2%, which greatly increased efficiency and reduced the cost of l-ascorbic acid manufacture in a two-step process.

Brain C-FOS expression and pressor responses after I.V. or I.C.V. angiotensin in the near-term ovine fetus

Fetal brain c-fos and cardiovascular responses after i.v. or i.c.v. angiotensin II administrations was determined in the near-term ovine fetuses. Both routes of angiotensin II markedly increased fetal mean arterial pressure. The latency of pressor responses by i.v. angiotensin II administration was shorter than by the i.c.v. route. The increased fetal mean arterial pressure was greater and transient by the i.v. route in comparison to that caused by i.c.v. angiotensin II administration. Following the i.v. administration of angiotensin II, the fetal heart rate was significantly decreased. Associated with fetal pressor responses and bradycardia, c-fos expression induced by i.v. angiotensin II was in the paraventricular nuclei (PVN) of the hypothalamus, and the area postrema, the tractus solitarius nuclei, and the lateral parabrachial nuclei in the brain stem. After i.c.v. angiotensin II administration, fetal blood pressure was also increased in association with the intensive c-fos expression in the PVN and the hindbrain. However, fetal heart rate was not affected by the central injection of angiotensin II. These results indicate that the central pathways between the forebrain circumventricular organs and the PVN have developed, and suggest that the neural activity in the hindbrain associated with bradycardia may be linked to the baroreflex. In the face of i.c.v. angiotensin II, sympathetic activation may play a predominant role in pressor responses. Taken together, these results suggest that central and peripheral angiotensin II-induced fetal pressor responses may be mediated by separate mechanisms, and these regulatory mechanisms start to function by near-term or early.

Analysis of incidence of atrial fibrillation after implantation of VVI pacemaker--long-term observation of 154 patients

Incidence of occurrence of atrial fibrillation (Af) after implantation of VVI was examined and the possible mechanism was explored. Eighty cases of atrioentricular block (AVB) and 74 cases of sick sinus syndrome (SSS) were studied and followed up for 1-14 years after implantation of VVI. The endpoint was the occurrence of permanent Af. The results showed that the incidence of Af among the 154 patients was 14.3% (22/154). And the incidence was 2.5% among patients with AVB (2/80), and 27% among patients with SSS (20/74). Significant significance was found between patients with AVB and those with SSS (P < 0.01). Among the patients with SSS, the incidence was 33.3% (9/27) in type I, 38.1% (8/21) in type III and 11.5% (3/26) in type II. Significant differences were revealed among patients with I, III and II type SSS (P < 0.05). It is concluded that retrograde conduction of pure ventricular pacing may play the chief role of occurrence of Af.

Neuroengineering modeling of single neuron and neural interface

The single neuron has attracted widespread attention as an elementary unit for understanding the electrophysiological mechanisms of nervous systems and for exploring the functions of biological neural networks. Over the past decades, much modeling work on neural interface has been presented in support of experimental findings in neural engineering. This article reviews the recent research results on modeling electrical activities of the single neuron, electrical synapse, neuromuscular junction, and neural interfaces at cochlea. Single neuron models vary form to illustrate how neurons fire and what the firing patterns mean. Focusing on these two questions, recent modeling work on single neurons is discussed. The modeling of neural receptors at inner and outer hair cells is examined to explain the transforming procedure from sounds to electrical signals. The low-pass characteristics of electrical synapse and neuromuscular junction are also discussed in an attempt to understand the mechanism of electrical transmission across the interfaces.

The RAD30 cancer susceptibility gene

The human skin cancer-prone disease xeroderma pigmentosum variant (XPV) results from a mutation in RAD30, which encodes the novel lesion bypass DNA polymerase eta. XPV cells are characterized by delayed completion of DNA replication and increased mutagenesis following UV irradiation. In cell-free extracts of XPV lymphoblasts, functional DNA polymerase eta is required for the complete replication of a double-stranded plasmid containing either a single (6-4) photoproduct or a cyclobutane pyrimidine dime(CPD), the major mutagenic UV-induced lesion. In cultured XPV cells, replication arrest activates downstream signalling pathways, leading to hyperphosphorylation of the 34-kDa subunit of the trimeric single-stranded DNA-binding protein, RPA (replication protein A). Many of the RAD30 mutations identified in XPV cells result in truncation and inactivation of DNA polymerase eta. To examine whether polymorphisms in the RAD30 gene that result in altered polymerase eta function, rather than enzyme inactivation, might contribute to individual susceptibility to skin cancer, methods to screen for sequence changes in the RAD30 gene in human genomic DNAhave been developed.