Rotenone induces KATP channel opening in PC12 cells in association with the expression of tyrosine hydroxylase

The activation of ATP-sensitive potassium (KATP) channels in PC12 cells play a pivotal role in protection against the neurotoxic effect of rotenone. However, it remains unclear why rotenone seems to preferentially affect activation of KATP channels and if this could affect its physiological activity. In this study, we sought to determine how the different energy states caused by various doses of rotenone affect the KATP opening state and whether the KATP opening state influences the expression of tyrosine hydroxylase (TH) which is related with DA synthesis. With patch clamp technology, results showed that treatment of PC12 cells with rotenone (0.2-1 µg/ml) for 15 min can cause KATP channel opening with significantly increased intracellular ROS production. Treatment with rotenone (2-16 ng/ml) for 24 h also caused the channels to open with gently increased ROS. In order to study if the rather long-term action on KATP channel opening states could affect the specified function of PC12 cells, the KATP channel opener pinacidil and the inhibitor glibenclamide were used to treat cells for 24 h, and the expression of TH was detected. Our results showed that treatment of PC12 cells with glibenclamide for 24 h can notably promote TH expression and can also enhance the expression of TH which were reduced by rotenone. These data indicate that the energy states in PC12 induced by various doses of rotenone could significantly influence the opening states of KATP channels. However long-term energy stress may raise the opening rate and opening sensitivity of this channel. In addition, our results demonstrate for the first time that activation of plasma membrane KATP channels induced by rotenone inhibits TH expression which influences DA synthesis in PC12 cells.

First Report of Volutella Blight on Pachysandra Caused by Volutella pachysandricola in China

Pachysandra (Pachysandra terminalis, Buxaceae) and Japanese Pachysandra, also called Japanese Spurge, is a woody ornamental groundcover plant distributed mostly in Zhejiang, Guizhou, Henan, Hubei, Sichuan, Shanxi, and Gansu provinces in China. In April 2010, P. terminalis asymptomatic plants were shipped from Beijing Botanical Garden Institute of Botany Chinese Academy of Science to the garden nursery of Jilin Agricultural University (43°48'N, 125°23'E), Jilin Province. In June 2011, Volutella blight (sometimes called leaf blight and stem canker) of P. terminalis was observed on these plants. Infected leaves showed circular or irregular, tan-to-brown spots often with concentric rings and dark margins. The spots eventually grew and coalesced until the entire leaf died. Cankers appeared as greenish brown and water-soaked diseased areas, subsequently turning brown or black, and shriveled and often girdled the stems and stolons. During wet, humid weather in autumn, reddish orange, cushion-like fruiting structures of the fungus appeared on the stem cankers and undersides of leaf spots. Symptoms of the disease were consistent with previous descriptions (2-4). Five isolates were obtained from necrotic tissue of leaf spots and cankers of stems and stolons and cultured on potato dextrose agar. The colony surface was salmon colored and slimy. Conidia were hyaline, one celled, spindle shaped, and 12.57 to 22.23 × 3.33 to 4.15 μm with rounded ends. Morphological characteristics of the fungus were consistent with the description by Dodge (2), and the fungus was identified as Volutella pachysandricola (telemorph Pseudonectria pachysandricola). The internal transcribed spacer (ITS) regions of the nuclear rDNA were amplified using primers ITS4/ITS5 (1). The ITS sequences were 553 bp long and identical among these five isolates (GenBank Accession No. HE612114). They were 100% identical to Pseudonectria pachysandricola voucher KUS-F25663 (Accession No. JN797821) and 99% identical to P. pachysandricola culture-collection DAOM (Accession No. HQ897807). Pathogenicity was confirmed by spraying leaves of clonally propagated cuttings of P. terminalis with a conidial suspension (1 × 10⁶ conidia/ml) of the isolated V. pachysandricola. Control leaves were sprayed with sterile water. Plants were covered with plastic bags and kept in a greenhouse at 20 to 25°C for 72 h. After 5 to 8 days, typical disease symptoms appeared on leaves, while the control plants remained healthy. V. pachysandricola was reisolated from the leaf spots of inoculated plants. Pachysandra leaf blight and stem canker also called Volutella blight, is the most destructive disease of P. terminalis and previously reported in the northern humid areas of the United States (Illinois, Connecticut, Ohio, Indiana, Iowa, Massachusetts, Missouri, Kentucky, and Wisconsin), northern Europe (Britain, Germany, and Poland), and the Czech Republic. To our knowledge, this is the first report of the disease caused by V. pachysandricola in China. The disease may become a more significant problem in P. terminalis cultivation areas if the disease spreads on P. terminalis in nursery beds. References: (1) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (2) B. O. Dodge. Mycologia 36:532, 1944. (3) S. M. Douglas. Online publication. Volutella Blight of Pachysandra. The Connecticut Agricultural Experiment Station, 2008. (4) I. Safrankova. Plant Protect. Sci.43:10, 2007.

First Report of Damping-Off of Rhodiola sachalinensis Caused by Rhizoctonia solani AG-4 HG-II in China

Rhodiola sachalinensis A. Bor (family Crassulaceae), a perennial herbaceous plant, is distributed mainly in the mountainous areas of China, Japan, Korea, and Russia. It is widely used as a traditional Chinese medicine with adaptogenic properties, cardiopulmonary protective effects, and central nervous system activities (3). Currently, it is extensively cultivated in northeastern China. In August 2010, widespread (>60% of plants were symptomatic) damping-off was observed in a seedling field in Linjiang, China. Leaves and stems near the ground were affected first, with dark lesions forming on the stem and the lowest leaves exhibiting wilt. The wilt spread rapidly over the entire plant with leaves becoming grayish brown and water soaked and then turned black and died. Root rot, defoliation, and damping-off were also observed. Six isolates with morphological characteristics of Rhizoctonia solani Kühn were isolated from symptomatic stems when plated on potato dextrose agar (PDA). Mycelium was branched at right angles with a septum near the branch and a slight constriction at the branch base. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia after 8 days on PDA. Hyphal cells removed from cultures grown at 25°C on 2% water agar were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400 magnification. The internal transcribed spacer (ITS) region of the nuclear rDNA was amplified by using the primers ITS4/ITS5 (2). The ITS sequences (715 bp) were identical in these six isolates (GenBank Accession No. FR878087) and had 100% sequence identity with R. solani AG-4 HG-II (GenBank Accession No. HQ629873) along with numerous other accessions from this AG subgroup. Pathogenicity tests were performed on healthy, potted seedlings of R. sachalinensis. Twenty plants were inoculated near the base of the stem with a 0.6-cm-diameter mycelial plug from 3-day-old PDA cultures for each isolate. Twenty plants inoculated with only PDA plugs served as controls. The plants were covered with plastic bags and kept in a greenhouse at 20 to 25°C for 72 h. All inoculated plants showed characteristic symptoms as previously observed in the seedling field 13 days after inoculation, while control plants remained healthy. R. solani AG-4 HG-II was reisolated from symptomatic tissues on inoculated plants. To our knowledge, this is the first report of R. solani AG-4 HG-II causing damping-off on R. sachalinensis in China. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (3) T. F. Yan et al. Conserv. Genet. 4:213, 2003.

First Report of Leaf Spot Disease on Dictamnus dasycarpus Caused by Phoma dictamnicola in China

Fraxinella, Dictamnus dasycarpus Turcz (Rutaceae), is a perennial herbal plant and mainly distributed in Eurasia and North America. It is often used to treat jaundice, cough, rheumatism, and other diseases and is extensively cultivated in the northeast and northwest of China (3). In June 2009, a severe foliar disease was observed on D. dasycarpus in medicinal plantations in Antu, China. The disease occurred on 100% of the plants and at least 25% of the surface was affected. In the early stages of disease development, symptoms were visible on the top and bottom of infected leaves as small brown spots. Subsequently, these spots became elliptical to irregularly shaped, with beige or grayish white centers and dark brown margins. Within the spots, numerous, dark brown or black, subglobose or ostiolate pycnidia measuring 152 to 367 μm in diameter were observed. Fungal isolates were obtained from the infected leaves on potato dextrose agar (PDA) medium, with conidia that were aseptate or one-septate and ellipsoidal or reniform, measuring approximately 4.7 to 12.6 × 2.1 to 4.5 μm. On the basis of these characteristics, the fungus was identified as a Phoma sp. Four well-sporulating isolates, designated as DdPh-1, DdPh-2, DdPh-3, and DdPh-4, were selected for further studies. The morphological and cultural characteristics of these four isolates were studied as described by Boerema et al. and the fungus was identified as Phoma dictamnicola Boerema et al. (1). The internal transcribed spacer (ITS) region of the nuclear rDNA was amplified and sequenced using primers ITS4/ITS5 (2). All four of the ITS sequences were identical (GenBank Accession No. FR681861) and were 99% identical to P. dictamnicola strains CBS507.91 (Accession No. GU237877) and KACC42445 (Accession No. EF600960). Pathogenicity tests were performed by spraying the leaves of healthy D. dasycarpus plants with a conidial suspension (1 × 10⁶ conidia/ml). Five plants were inoculated with each isolate (DdPh-1, DdPh-2, DdPh-3, and DdPh-4) and five plants were mock inoculated with sterile water. The plants were covered with plastic bags and kept in a greenhouse at 20 to 25° for 72 h. After 9 to 13 days, all inoculated plants showed characteristic symptoms as previously described, while the control plants remained healthy. The fungus was reisolated from the leaf spots of inoculated plants. Currently, the economic importance of this disease is limited, but it may become a more significant problem in production of D. dasycarpus with the cultivation area increasing. The fungus was found in the Netherlands and Korea, but to our knowledge, this is the first report of P. dictamnicola on D. dasycarpus in China. References: (1) G. H. Boerema et al. Phoma Identificatión Manual: Differentiation of Specific and Infra-Specific Taxa in Culture. CABI Publishing. Wallingford, U.K., 2004. (2) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (3) S. S. Jiang et al. Biosci. Biotechnol. Biochem. 72:660, 2008.

First Report of Seedling Blight Caused by Rhizoctonia solani on Dioscorea nipponica in China

Throughhill yam (Dioscorea nipponica Makino), a perennial winding herb and a member of the Discoreaceae, is distributed principally in northeast Asia. It is used to produce medicine for treating coronary heart disease, diabetes mellitus, and inflammation. In China, this species is cultivated in many provinces such as Liaoning, Jilin, Heilongjiang, Hebei, Inner Mongolia, and Shanxi. In July 2006, seedling blight was observed on D. nipponica with disease incidence ranging from 37 to 75% in commercial fields in Antu County, China. In the early stages of disease development, water-soaked lesions appeared at the stem base and on leaves near the ground. Lesions later turned dark brown and necrotic. Leaves eventually became chlorotic, stem and petioles collapsed gradually, and plants died. Mycelium was observed to be growing on the surface of infected tissues and adjacent plants, and brown, hard sclerotia were produced on stem or petiole surfaces. A fungus with morphological characteristics of Rhizoctonia solani Kühn was consistently isolated from diseased tissues that were plated on potato dextrose agar (PDA). Mycelium was branched at right angles with a septum near the branch and a slight constriction at the branch base. Cells from hyphae grown on 2% water agar at 25°C were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400. Anastomosis groups were determined by pairing isolates with 12 tester strains representing all subgroups of AG1 to AG5 on 2% water agar in petri plates (2). The anastomosis grouping of isolates Rs1, Rs2, and Rs5 was determined to be AG1-IB and that of isolates Rs3 and Rs6 was determined to be AG2-1. The rDNA internal transcribed spacer (ITS) gene sequence of isolates Rs1, Rs2, and Rs5 (GenBank Accession Nos. GU585667, GU596490, and GU594691) had 100, 99, and 100% nucleotide identity, respectively, with AG1-IB (GenBank Accession No. FG440191). The rDNA-ITS of isolates Rs3 and Rs6 (GenBank Accession Nos. GU596493 and GU594692) exhibited 99% homology with AG2-1 (GenBank Accession No. EU513135). Pathogenicity tests were performed on healthy, potted 2-year-old plants of D. nipponica. Twenty plants were wound inoculated by placing 0.6-cm mycelial plugs from 3-day-old PDA cultures on leaves and stems. Twenty plants were treated with PDA plugs as controls. Plants were maintained at 25°C and 95% relative humidity on a 12-h light/dark regimen. Typical symptoms of leaf and stem rotting identical to those observed in the commercial field appeared 4 days after inoculation and all inoculated plants died within 10 days. No disease symptoms were observed on control plants. Rhizoctonia solani was consistently reisolated from symptomatic tissues. To our knowledge, this is the first report of R. solani causing seedling blight on D. nipponica in the world. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

Cis-acting elements responsible for dopaminergic neuron-specific expression of zebrafish slc6a3 (dopamine transporter) in vivo are located remote from the transcriptional start site

The purpose of this study was to analyze the transcriptional regulation of the zebrafish solute carrier family 6 member 3 gene (slc6a3, dopamine transporter, dat), as a first step towards isolating regulatory sequences useful for driving transgene expression within dopaminergic neurons of the zebrafish CNS in vivo. We found that the 3.0 kb slc6a3 mRNA is expressed in each of the major groups of dopaminergic neurons previously identified in the zebrafish CNS. The slc6a3 gene spans >20 kb of genomic DNA and contains 15 exons. The genomic organization of slc6a3 is highly conserved with respect to its human orthologue, including the presence of an untranslated first exon. The promoter lacks a canonical TATA box and there are multiple transcriptional start sites. Functional analysis of cis-acting elements responsible for the expression pattern of slc6a3 was carried out by generating stable transgenic zebrafish lines expressing fluorescent reporters under transcriptional control of fragments of slc6a3 genomic sequence. The region between -2 kb and +5 kb with respect to the transcriptional start site contains the core slc6a3 promoter, in addition to neuronal enhancers and/or non-neuronal repressors that restrict expression to the CNS, but this region lacks cis-acting elements responsible for slc6a3 expression in dopaminergic neurons. The upstream sequence between -6 kb and -2 kb contains an enhancer element that drives slc6a3 expression in dopaminergic neurons of the pretectal region, and additional sequences that partially repress expression in non-dopaminergic neurons. However, expression of slc6a3 in dopaminergic neurons of the ventral diencephalon and telencephalon is dependent on elements that lie outside the region -6 kb to +5 kb. These data provide a detailed analysis of the slc6a3 gene and show that its expression in different populations of dopamine neurons is driven by discrete enhancers, rather than a single target sequence for a terminal factor involved in specifying neurochemical phenotype.

Microarray expression profiling of Yersinia pestis in response to berberine

Coptis chinensis Franch. is a natural herb widely used in China for prevention and treatment of infectious diseases. Plague is a deadly disease caused by Yersinia pestis. Coptis chinensis Franch. is considered the therapeutic agent of choice against plague rather than conventional antibiotics because of its low cost and low toxicity. Berberine is the major constituent of a Coptis chinensis Franch. extract. In the present study, DNA microarray was used to investigate the transcription of Y. pestis in response to berberine. The minimal inhibition concentration (MIC) of berberine to Y. pestis was determined with the liquid dilution method. The gene expression profile of Y. pestis was performed by exposing Y. pestis to berberine at a concentration of 10 x MIC for 30 min. Total RNA was extracted and purified from Y. pestis, reverse-transcribed to cDNA, and then labeled with Cy-dye probes. The labeled probes were hybridized to the microarray. The results were obtained by a laser scanner and analyzed with SAM software. A total of 360 genes were differentially expressed in response to berberine: 333 genes were upregulated, and 27 were downregulated. The upregulation of genes that encode proteins involved in metabolism was a remarkable change. In addition to a number of genes of unknown encoding or unassigned functions, genes encoding cellular envelope and transport/binding functions represented the majority of the altered genes. A number of genes related to iron uptake were induced. This study revealed global transcriptional changes of Y. pestis in response to berberine, hence providing insights into the mechanisms of Coptis chinensis Franch. against Y. pestis.

[Study of molecular mechanism of Rheum offcinale against Yersinia pestis]

To investigate molecular mechanism of traditional Chinese medicine Rheum offcinale against Yersinia pestis, whole genome DNA microarray that contains 4005 annotated genes of Y. pestis was used. The minimal inhibition concentration (MIC) of R. offcinale extract against Y. pestis was determined by liquid dilution method. The gene expression profile of Y. pestis was performed after exposured to R. offcinale extract at a concentration of 10 X MIC for 30 and 60 minutes. The total RNA extracted and purified from Y. pestis were reverse-transcribed to cDNA and labeled by Cy3-Cy5 dye. The labeled probes were hybridized to the microarray and the results were obtained by a laser scanner and analyzed by the SAM software. The microarray data was confirmed by RT-PCR. The platform of the DNA microarray-based bacteria transcriptional profiling was eshtablished. The results revealed general gene expression changes of Y. pestis were a global phenomenon. Down-regulation of genes encoding proteins involved in ribosome protein synthesis was a remarkable change. Genes encoding cell envelope and transport/binding proteins were the major changed genes of the Y. pestis in response to R. offcinale.

At least two genetically distinct large Babesia species infective to sheep and goats in China

A fatal disease of sheep and goats in the northern part of China has been reported to be due to Babesia ovis. However, some characteristics of the causative agent in recent reports are not in accordance with the original attributes ascribed to this parasite. Therefore, the 18S small subunit ribosomal RNA (18S rRNA) genes of a number of Babesia isolates in China were sequenced and compared with that of other Babesia and Theileria species in an attempt to clarify their taxonomic position. In the present study, seven Babesia isolates were collected from distinct areas of northern China, and the 18S rRNA genes were amplified and sequenced. The phylogenetic trees were inferred based on 18S rRNA gene sequences of the Chinese ovine Babesia isolates and some of ovine Babesia and Theileria species available in GenBank. In the phylogenetic tree, Babesia sp. isolates from Madang, Tianzhu, Lintan, Ningxian, Hebei and Liaoning all grouped with B. motasi with 88.2-99.9% identity, while Babesia sp. Xinjiang grouped in a separate clade between B. ovis and B. crassa with 79.7-81.2% identity. The results indicated that there are at least two distinct Babesia species groups-B. motasi and Babesia sp. Xinjiang, the latter was distinctly different from other ovine Babesia isolates from China with less than 86.6% identity.

Surgical treatment of intractable epilepsy combined with bipolar electrocoagulation on functional cortex

OBJECTIVE

Resecting epileptogenic foci combined with bipolar electrocoagulation of functional cortex has been successfully used to treat intractable epilepsy.

METHOD

124 cases with intractable epilepsy have been treated from 1996 to 1999, 75 cases with temporal lobe epilepsy and 48 cases with extra-temporal lobe epilepsy, and one case with infantile hemiplegia. Electrocorticography (ECoG) was used pre- and postoperatively. 108 cases were followed-up from one to three years.

RESULTS

The general efficiency of bipolar electrocoagulation on functional cortex (BCFC) for epilepsy is 91.7%. The pathological features indicate that the damage by coagulation of the cortex is only in the supra- and infra-granular layers, similar to multiple subpial transection (MST).

CONCLUSION

When the epileptogenic foci are located in functional cortex, the method of resecting the foci combined with BCFC has been effective and improves the results greatly. BCFC is safe and easy to use.

Influence of acetazolamide on AQP1 gene expression in testis and on sperm count/motility in epididymis of rats

Acetazolamide (Ace) is a putative inhibitor of carbonic anhydrase (CA), an enzyme that catalyzes the equilibration of carbon dioxide and carbonic acid and plays a key role in HCO(3)(-) and water reabsorption and acid secretion. Aquaporins (AQPs) are channel-forming membrane glycoproteins that mediate water reabsorption by the renal tubules and other organs of mammals. AQP1 and CAII or CAIV share many common biological properties. Previous studies have shown that AQP1 and CA are located at the same sites in cells of the male reproductive tract. In the present study, Ace at a dose of 40 mg/kg/d x 14, administered per os, suppressed AQP1 gene expression and inhibited CA activity in rat testis. On day 7 of treatment the epididymal sperm motility was significantly reduced, while on day 14 a decrease in sperm count occurred. Ace caused a marked downregulation of AQP1 gene expression; significant suppression occurred on days 7 and 14. Moreover, CA activity was totally blocked throughout the treatment period. The present findings suggest that the reduction of rat sperm motility and count by Ace can be attributed to its capacity to downregulate AQP1 water channel gene expression.

Targeting gene expression using HSV vectors

Herpes simplex virus (HSV) is an encapsulated DNA virus, with many favourable properties for use as a gene transfer vector. For gene therapy applications, it may be desirable to restrict transgene expression to pre-defined subsets of cells. One potential method for achieving targeted transgene expression using the HSV vector system might involve dictating the cell types to which the vector will transfer the therapeutic transgene of interest. HSV delivers its genetic payload to cells directly through the plasmalemma; the mechanisms are complex and involve multiple viral and cell surface determinants. We have investigated several ways in which each component of the cell entry cascade may be manipulated in order to restrict viral DNA and transgene delivery to particular cellular populations. Our results indicate that targeted transduction may be a viable approach to achieving our goal of targeted HSV-mediated transgene expression.

Single-unit neural recording with active microelectrode arrays

This paper discusses the single-unit recording characteristics of microelectrode arrays containing on-chip signal processing circuitry. Probes buffered using on-chip unity-gain operational amplifiers provide an output resistance of 200 ohm with an input-referred noise of 11-muV root-mean-square (rms) (100 Hz-10 kHz). Simultaneous in vivo recordings from single neurons using buffered and unbuffered (passive) iridium recording sites separated by less than 20 microm have shown that the use of on-chip circuitry does not significantly degrade system noise. Single-unit neural activity has also been studied using probes containing closed-loop preamplifiers having a voltage gain of 40 dB and a bandwidth of 13 kHz, and several input dc-baseline stabilization techniques have been evaluated. Low-noise in vivo recordings with a multiplexed probe have been demonstrated for the first time using an external asymmetrical clock running at 200 kHz. The multiplexed system adds less than 8-muV rms of noise to the recorded signals, suppressing the 5-V clock transitions to less than 2 ppm.

[Expression of human papillomavirus DNA in cholesteatoma of the middle ear]

OBJECTIVE

To reveal the role of HPV in the occurrence and development of cholesteatoma of the middle ear.

METHOD

PCR and nuclear acid hybridization were applied in screening 44 cases of middle ear cholesteatoma for detection of HPV DNA, and a comparison analysis with the pathological results of 35 cases of middle ear cholesteatoma was made.

RESULTS

Pathologically, the characteristics of HPV induced-lesions was found in 12 of 35 specimens (34.3%). 44 cases of middle ear cholesteatoma were examined with consensus primers PCR and digoxigenin labeled HPV general probes. HPV DNA positive rates were 29.5% (13/44) and 25.0% (11/44) respectively. HPV DNA positive rate was 58.3% (7/12) and 13.0% (3/23) respectively in 12 cases with pathological characteristics of HPV induced-lesions and in 23 cases without those characteristics. There was significant difference(chi 2 = 7.926, P < 0.005).

CONCLUSIONS

HPV infection can arouse the cleavage and proliferation of cholesteatoma epithelium and may play certain role in the occurrence and development of middle ear cholesteatoma. Aggressive, papillomatous growth and koilocytes can be served as the initial proof of HPV infection in cholesteatoma of the middle ear.

[Thermodynamic characteristics of stoichiometric displacement linear parameter log I in reversed-phase liquid chromatography]

Based on the physical meaning of each term in the linear parameter log I (a constant correlating the affinity of solute to stationary phase) of stoichiometric displacement model for retention(SDM-R) of solute, the thermodynamic characteristics of log I of solute in reversed-phase liquid chromatography (RPLC) were investigated theoretically. This point was tested by experimental data with two linear relationships: (1) plot of log I vs 1/T (T is absolute temperature) with apolar, polar small solutes and proteins; (2) plot of log I vs log Po/w (partition coefficient of solute between n-octanol and water) with apolar and polar small solutes. From the comparison of the magnitude of partition coefficient between small solute and proteins, a phenomenon that the resolution of small solutes depends on column length but that of proteins almost to be independent of column length is quantitatively explained.

Characterization of Microbial Consortia in Paddy Rice Soil by Phospholipid Analysis

Microbial biomass and community structure in paddy rice soil during the vegetation period of rice were estimated by analysis of their phospholipid fatty acids (PLFA), hydroxy fatty acids of lipopolysaccharides (LPS-HYFA), and phospholipid ether lipids (PLEL) directly extracted from the soil. A clear change in the composition of the community structure at different sampling periods was observed, indicated by the principal component analysis of the PLFA. A dramatic decline of ester-linked PLFA was observed in the soil samples taken at the second sampling time. In contrast to the ester-linked PLFA, the non-ester-linked PLFA composition did not change. The hydroxy fatty acids of lipopolysaccharides as well as ether lipids decreased consecutively during the observation period. Total microbial abundance was estimated to be (4.1-7.3) x 10(9) cells g(-1) soil (dry weight). About 44% account for aerobic and 32% for facultative anaerobic bacteria, and 24% for archaea, on average. According to the profile and patterns of PLFA in the soil sample, it may be suggested that the paddy soil at the August sampling period contained more abundant facultative anaerobic bacteria (ca. 36%) and archaea (ca. 37%), but the total microbial biomass was significantly lower than in the remaining sampling periods. As the plant approached maturity, the microbial community structure in the soil changed to contain more abundant Gram-negative bacteria and methanotrophs.

A high-yield microassembly structure for three-dimensional microelectrode arrays

This paper presents a practical microassembly process for three-dimensional (3-D) microelectrode arrays for recording and stimulation in the central nervous system (CNS). Orthogonal lead transfers between the micromachined two-dimensional probes and a cortical surface platform are formed by attaching gold beams on the probes to pads on the platform using wire-free ultrasonic bonding. The low-profile (150 microns) outrigger design of the probes allows the bonding of fully assembled high-density arrays. Micromachined assembly tools allow the formation of a full 3-D probe array within 30 min. Arrays having up to 8 x 16 shanks on 200-micron centers have been realized and used to record cortical single units successfully. Active 3-D probe arrays containing on-chip CMOS signal processing circuitry have also been created using the microassembly approach. In addition, a dynamic insertion technique has been explored to allow the implantation of high-density probe arrays into feline cortex at high-speed and with minimal traumatic injury.

[Studies on the antitumour effect of Alocasia macrorrhiza]

Models of transplanted tumour in mice and human cancer enograft in nude mice were used to evaluate the antitumour effect of water extract of Alocasia macrorrhiza. Results showed that the inhibitory rate against S180 in mice was 29.38%, and the inhibitory rate against transplantable humman gastroadenitis in nude mice was 51.72%. No antitumour effect was shown against ECA in mice.

Integration host factor and cyclic AMP receptor protein are required for TyrR-mediated activation of tpl in Citrobacter freundii

The tpl gene of Citrobacter freundii encodes an enzyme that catalyzes the conversion of L-tyrosine to phenol, pyruvate, and ammonia. This gene is known to be positively regulated by TyrR. The amplitude of regulation attributable to this transcription factor is at least 20-fold. Three TyrR binding sites, designated boxes A, B, and C, centered at coordinates -272.5, -158.5, and -49.5, respectively, were identified in the upstream region of the tpl promoter. The results of mutational experiments suggest that TyrR binds in cooperative fashion to these sites. The nonavailability of any TyrR site impairs transcription. Full TyrR-mediated activation of tpl required integration host factor (IHF) and the cAMP receptor protein (CRP). By DNase I footprinting, it was shown that the IHF binding site is centered at coordinate -85 and that there are CRP binding sites centered at coordinates -220 and -250. Mutational alteration of the IHF binding site reduced the efficiency of the tpl promoter by at least eightfold. The proposed roles of CRP and IHF are to introduce bends into tpl promoter DNA between boxes A and B or B and C. Multimeric TyrR dimers were demonstrated by a chemical cross-linking method. The formation of hexameric TyrR increased when tpl DNA was present. The participation of both IHF and CRP in the activation of the tpl promoter suggests that molecular mechanisms quite different from those that affect other TyrR-activated promoters apply to this system. A model wherein TyrR, IHF, and CRP collaborate to regulate the expression of the tpl promoter is presented.

[Gene diagnosis of 10 Chinese families with adult polycystic kidney disease from Guangxi region]

OBJECTIVE

To study presymptomatic gene diagnosis in adult polycystic kidney disease (APKD).

METHODS

Linkage analysis and haplotype characterization were carried out in 10 unrelated Chinese APKD families from Guangxi region, including 97 individuals and 29 affected members. Members of these families were ultrasonographically examined. Linkage to PKD1 was investigated in all families with four microsatellite markers(SM7, CW2, AC2.5, and KG8). These flanking markers were amplified by PCR.

RESULTS

The families were fully informative for gene diagnosis and no evidence of genetic heterogeneity was found. DNA analysis predicted 7 asymptomatic individuals(by 28 years old) as being affected, although they all presented negative ultrasonographs.

CONCLUSION

Linkage analysis is still an important way in APKD presymptomatic gene diagnosis.

An unidentified species of Theileria infective for cattle discovered in China

Infection experiments, morphological observations and transmission experiments were conducted with an unidentified Theileria sp. isolated from a naturally infected ox. The results showed that the protozoa could multiply extensively in a splenectomized ox and the parasitaemia could reach 52.69%. The Theileria sp. was polymorphic: being pear-shaped, circular, elliptical, rod-like, comma-shaped, three-leafed- or cross-shaped and having many other irregular-shapes which were seldom detected. In erythrocytes, the anaplasma-like protozoa grew, producing protoplasm which could extend and clump together, and developed into many polymorphic protozoa. Some of the protozoa propagated themselves by budding. The protozoa could not be transmitted by Haemaphysalis longicornis or Hyalomma detritum. The pathogenicity, vector ticks and life cycle of this protozoan are unknown.

Effect of sedative and hypnotic doses of propofol on the EEG activity of patients with or without a history of seizure disorders

Propofol is alleged to possess both pro- and anticonvulsant properties, leading to controversy regarding its use in patients with a history of seizures. Since propofol is administered for both sedation and hypnosis, it is important to understand the effects of low (0.5-1.0 mg/kg) and high (2-2.5 mg/kg) doses of propofol on the electroencephalogram (EEG). In this study, the hemodynamic and EEG effects of cumulative doses of propofol from 0.5 to 2.5 mg/kg i.v. were studied in 30 neurosurgical patients with or without a history of seizure disorders. While continuously recording from scalp EEG electrodes (F3, F4, C3, C4, P3, P4, O1, and O2), propofol 0.5 mg/kg was infused intravenously over 20 s. The same dose of propofol was reinjected four times at 2-min intervals, until a total dose of 2.5 mg/kg had been administered. The number and average amplitude of the EEG waves were counted and measured manually, respectively, from 80 to 90 s after beginning the injection of each dose of propofol. After lower propofol doses (0.5-1 mg/kg), the number of beta-waves increased, while alpha- and theta-waves decreased significantly in all patients. However, with larger doses of propofol (total dose of 2-2.5 mg/kg), the number of beta-waves decreased and delta-waves appeared. The amplitudes of all EEG waves increased and were maintained at a higher level after administration of propofol. Spike (or sharp) waves appeared in 33% of the control patients and in 40% of the epileptic group after propofol 0.5 mg/kg and in 73% of the control and 67% of the epileptic patients after the 1.5-mg/kg dose. In the majority of patients, the spike waves disappeared when additional doses of propofol were administered. One patient in the epileptic group had an EEG-recorded and clinical grand mal seizure after propofol 1 mg/kg, but the seizure disappeared after an additional 0.5-mg/kg bolus dose was administered. The propofol-induced EEG changes appeared initially at the frontal and central EEG electrodes and subsequently at the other EEG electrodes. Overall, there were no significant differences in the spectrum of EEG changes between the two patient populations. It is concluded that propofol produces similar dose-dependent effects on EEG activity in patients with or without a history of seizure disorders. While induction of anesthesia with higher doses of propofol (> 1.5 mg/kg) in neurosurgical patients with well controlled seizure disorder is safe, smaller sedative doses should be administered with caution to epileptic patients.

[Investigation of alpha-amylase denatured by urea and guanidine hydrochloride. I. Studies on denaturation mechanism and renaturation efficiency by high-performance hydrophobic interaction chromatography]

The varieties of alpha-amylase denatured with 8.0 mol/L urea and 7.0 mol/L guanidine hydrochloride (GuHCl) solutions and their refolded intermediates were separated and renatured through high performance hydrophobic interaction chromatography (HPHIC). With investigating and comparing the numbers of the refolded intermediates and the bioactivity recovery of renaturation by means of HPHIC, it was found that these are quite different. The results can be attributed to the different denaturation mechanism of alpha-amylase with the two denaturing agents. The numbers of the refolded intermediates of urea-unfolded alpha-amylase were found to be more than that denatured by GuHCl, because GuHCl may make the changes in the surface of alpha-amylase molecules, by contrast, urea may do the changes not only in the surface of the protein, but also in the hydrophobic packet interior of the molecules. The HPHIC packings with weak hydrophobicity was found to have good separation efficiency and to have almost continuous and many peaks denoting these intermediates, while that with strong hydrophobicity was found to have higher bioactivity recovery. The numbers of the intermediates of urea-unfolded alpha-amylase were much more than that of bovine pancreatic trypsin inhibitor (BPTI) separated by Weissman et al. The effect of temperature on the separations and the renaturations were investigated too. The result showed that the higher the column temperature, the more the refolded intermediates of unfolded alpha-amylase separated and the lower bioactivity recovery were obtained from HPHIC.