Winter spatial distribution of fish larvae assemblages relative to the hydrography of the waters surrounding Taiwan

The aim of this study was to investigate the species composition and distribution of fish larvae in relation to hydrographic conditions in the waters surrounding Taiwan Island (TI) in February 2003. In total, 242 kinds of fish larvae belonging to 127 genera and 75 families were recognized. Among these, 109 taxa were identified to the family or genus level, others to the species level. The 12 predominant types, which constituted 71% of the total fish larvae, were Engraulis japonica, Scomber sp., Diaphus spp., Benthosema pterotum, Carangoides ferdau, Embolichthys mitsukurii, Maurolicus sp., unidentified Myctophidae, Gonostoma gracile, Trichiurus lepturus, unidentified Gobiidae, and Myctophum asperum. The distribution of fish larvae showed a clear association with water masses around TI, with higher abundances and lower species richness northwest of TI where the China Coastal Current prevails, and lower abundances and higher species diversity east of TI where the Kuroshio Current dominates. Cluster analysis distinguished three station groups and four species groups, and the distribution patterns of fish larvae also corresponded to hydrographic conditions. The total abundances of fish larvae and eight of the 12 predominant taxa showed significant and positive correlations with zooplankton abundance, which suggests that food source might be a key factor determining the abundance and distribution of fish larvae during the winter.     

Studies on the Utilization of Hydrocarbons by Microorganisms

Taxonomical studies on ten strains of hydrocarbon-utilizing bacteria reported in previous paper, which produced various kinds of amino acid, were carried out. They were Achromo-bacter cycloclastes, Achromobacter delmarvae, Bacillus species, Corynebacterium species, Micrococcus species. Many of them were not identical with the species which are described in Bergey’s Manual of 7th Edition.     

<Emphasis Type="Italic">Narcissus tazetta</Emphasis> lectin shows strong inhibitory effects against respiratory syncytial virus,influenza A (H1N1, H3N2, H5N1) and B viruses

A mannose-binding lectin (Narcissus tazetta lectin [NTL]) with potent antiviral activity was isolated and purified from the bulbs of the Chinese daffodil Narcissus tazetta var. chinensis, using ion exchange chromatography on diethylaminoethyl (DEAE)-cellulose, affinity chromatography on mannose-agarose and fast protein liquid chromatography (FPLC)-gel filtration on Superose 12. The purified lectin was shown to have an apparent molecular mass of 26 kDa by gel filtration and 13 kDa by SDS-PAGE, indicating that it is probably a dimer with two identical subunits. The cDNA-derived amino acid sequence of NTL as determined by molecular cloning also reveals that NTL protein contains a mature polypeptide consisting of 105 amino acids and a C-terminal peptide extension. Three-dimensional modelling study demonstrated that the NTL primary polypeptide contains three subdomains, each with a conserved mannose-binding site. It shows a high homology of about 60%–80% similarity with the existing monocot mannose-binding lectins. NTL could significantly inhibit plaque formation by the human respiratory syncytial virus (RSV) with an IC₅₀ of 2.30 μg/ml and exhibit strong antiviral properties against influenza A (H1N1, H3N2, H5N1) and influenza B viruses with IC₅₀ values ranging from 0.20 μg/ml to 1.33 μg/ml in a dose-dependent manner. It is worth noting that the modes of antiviral action of NTL against RSV and influenza A virus are significantly different. NTL is effective in the inhibition of RSV during the whole viral infection cycle, but the antiviral activity of NTL is mainly expressed at the early stage of the viral cycle of influenza A (H1N1) virus. NTL with a high selective index (SI=CC₅₀/IC₅₀≥141) resulting from its potent antiviral activity and low cytotoxicity demonstrates a potential for biotechnological development as an antiviral agent.     

Lessons on Evolution from the Study of Edaphic Specialization

Plants adapted to special soil types are ideal for investigating evolutionary processes, including maintenance of intraspecific variation, adaptation, reproductive isolation, ecotypic differentiation, and the tempo and mode of speciation. Common garden and reciprocal transplant approaches show that both local adaptation and phenotypic plasticity contribute to edaphic (soil-related) specialization. Edaphic specialists evolve rapidly and repeatedly in some lineages, offering opportunities to investigate parallel evolution, a process less commonly documented in plants than in animals. Adaptations to soil features are often under the control of major genes and they frequently have direct or indirect effects on genes that contribute to reproductive isolation. Both reduced competitiveness and greater susceptibility to herbivory have been documented among some edaphic specialists when grown in ‘normal’ soils, suggesting that a high physiological cost of tolerance may result in strong divergent selection across soil boundaries. Interactions with microbes, herbivores, and pollinators influence soil specialization either by directly enhancing tolerance to extremes in soil conditions or by reducing gene flow between divergent populations. Climate change may further restrict the distribution of edaphic specialists due to increased competition from other taxa or, expand their ranges, if preadaptations to drought or other abiotic stressors render them more competitive under a novel climate.     

Monitoring oxygen consumption of single mouse embryos using an integrated electrochemical microdevice

Oxygen consumption (respiration activity) has been found to be the most remarkable criterion for determining the viability of an embryo produced in vitro. In this study, we propose an accurate, simple, and user-friendly device for measurement of the oxygen consumption of single mammalian embryos. An integrated electrode array was fabricated to determine the oxygen consumption of a single embryo, including the blastocyst stage, which has an inhomogeneous oxygen consumption rate, using a single measurement procedure. A single mouse embryo was positioned in a microwell at the center of an integrated electrode array, using a mouthpiece pipette, and immobilized by a cylindrical micropit with good reproducibility. The oxygen consumption of two-cell, morula, and blastocyst stages was measured amperometrically using the device. The recorded current profile was corrected to take into consideration transient background current during the measurement. A calculation method for oxygen consumption based on spherical diffusion centered on the defined point of the device was developed. This procedure is quite simple because it is not necessary to estimate the radius of the embryo being measured. The calculated values of oxygen consumption for two-cell, morula, and blastocyst stages were 1.36 ± 0.33 × 10⁻¹⁵ mol s⁻¹, 1.38 ± 0.58 × 10⁻¹⁵ mol s⁻¹, and 3.44 ± 2.07 × 10⁻¹⁵ mol s⁻¹, respectively. The increasing pattern of oxygen consumption from morula to blastocyst agreed well with measurements obtained using conventional scanning electrochemical microscopy (SECM).     

Characterization of an insulin-related factor secreted by a teratoma cell line

The teratoma-derived insulin-independent cell line 1246-3A produces and secretes polypeptide mitogens in its culture serum-free medium. Mitogenic activities were separated by Sephadex G-50 chromatography into two fractions eluted, one in the void volume region, another one with an apparent Mr of 6 kDa. Only the 6 kDa mitogen presents properties similar to pancreatic insulin as estimated by radioimmunoassay, radio-receptor assay, and biochemical characterization. As a consequence, this factor is called insulin-related factor (IRF). Evidence presented in this paper indicate that ectopic IRF binds to insulin receptors on the producer cells, 1246-3A and acts in an autostimulatory manner.     

Ultraviolet-induced suppressor T cells and factor(s) in murine contact photosensitivity. I. Biological and immunochemical characterization of factor(s) extracted from suppressor T cells

Murine contact photosensitivity (CPS) to 3,3',4',5-tetrachlorosalicylanilide (TCSA) is a highly specific, T-cell-mediated delayed-type hypersensitivity (DTH). Preexposure of the photosensitizing site to low doses of ultraviolet B(UVB) rendered mice unresponsive to challenge reaction. This unresponsiveness was associated with the generation of antigen-specific, afferent limb-acting, Lyt-1+2-,L3T4+ suppressor T cells (Ts-cps) in the spleen, thymus, and lymph node. Cell-free extract(s) obtained by freezing and thawing of these cells contained T-cell-suppressor factor (TsF) that inhibited the development of the induction phase of the CPS response to TCSA in vivo in an antigen-specific fashion. The treatments of TsF both with immunoadsorbent columns and with reduction and alkylation showed that the factor bore photoantigen-binding site(s), was reactive with monoclonal anti-I-Jd, anti-I-E alpha but not anti-I-Ad, and behaved as a single-chain factor containing both photoantigen binding and I-J molecules. By gel chromatography the majority of the suppressive activity was eluted in the fractions corresponding to molecular weights of 60-80 and 100-200 kDa. Our present study demonstrated clearly that UVB-induced unresponsiveness in the DTH reaction was mediated by a soluble suppressive factor derived from T cells.     

Secretory and continuous expression of Aspergillus niger glucose oxidase gene in Pichia pastoris

We proposed a yeast transformant cell incorporating the Aspergillus niger glucose oxidase gene (GOX gene), which is capable of constitutively as well as secretory expression. The GOX gene has been cloned in this study. This conclusion is based on the following: first, the ligated DNA determined by electrophoresis, was a 1489-1882bp fragment, close to the size of glucose oxidase (GOD), which is 1818bp. Secondly, the single open reading frame encoded a protein of 605 amino acids. Thirdly, secreted GOD recombinant proteins in the culture supernatants of the GOX gene transformant migrated as a single band in SDS-PAGE with an apparent molecular mass of between 75,000 and 100,000 Da, which is glycosylated GOD by the Pichia pastoris X-33 host machinery during the secretion process. Finally, the clones were cultured and secreted a protein, which possessed the GOD activity of catalyzing beta-d-glucose oxidation. With regard to the pH characteristics, the activity was more than 80% of the maximum activity in the range between pH 5 and pH 7. As for the temperature characteristics, the activity was not less than 92% of the maximum in the temperature range between 10 and 45 degrees C. The GOX gene transformant was able to maintain the GOD enzyme activity and produce recombinant GOD continuously for at least 2 weeks.     

Aluminum-Induced Cholinergic Deficits in Different Brain Parts and Its Implications on Sociability and Cognitive Functions in Mouse

Aluminum is associated with etiology of many neurodegenerative diseases specially Alzheimer’s disease. Chronic exposure to aluminum via drinking water results in aluminum deposition in the brain that leads to cognitive deficits. The study aimed to determine the effects of aluminum on cholinergic biomarkers, i.e., acetylcholine level, free choline level, and choline acetyltransferase gene expression, and how cholinergic deficit affects novel object recognition and sociability in mice. Mice were treated with AlCl₃ (250 mg/kg). Acetylcholine level, free choline level, and choline acetyltransferase gene expression were determined in cortex, hippocampus, and amygdala. The mice were subjected to behavior tests (novel object recognition and social novelty preference) to assess memory deficits. The acetylcholine level in cortex and hippocampus was significantly reduced in aluminum-treated animals, as compared to cortex and hippocampus of control animals. Acetylcholine level in amygdala of aluminum-treated animals remained unchanged. Free choline level in all the three brain parts was found unaltered in aluminum-treated mice. The novel object recognition memory was severely impaired in aluminum-treated mice, as compared to the control group. Similarly, animals treated with aluminum showed reduced sociability compared to the control mice group. Our study demonstrates that aluminum exposure via drinking water causes reduced acetylcholine synthesis in spite of normal free choline availability. This deficit is caused by reduced recycling of acetylcholine due to lower choline acetyltransferase level. This cholinergic hypofunction leads to cognitive and memory deficits. Moreover, hippocampus is the most affected brain part after aluminum intoxication.     

The twin-arginine translocation system and its capability for protein secretion in biotechnological protein production

The biotechnological production of recombinant proteins is challenged by processes that decrease the yield, such as protease action, aggregation, or misfolding. Today, the variation of strains and vector systems or the modulation of inducible promoter activities is commonly used to optimize expression systems. Alternatively, aggregation to inclusion bodies may be a desired starting point for protein isolation and refolding. The discovery of the twin-arginine translocation (Tat) system for folded proteins now opens new perspectives because in most cases, the Tat machinery does not allow the passage of unfolded proteins. This feature of the Tat system can be exploited for biotechnological purposes, as expression systems may be developed that ensure a virtually complete folding of a recombinant protein before purification. This review focuses on the characteristics that make recombinant Tat systems attractive for biotechnology and discusses problems and possible solutions for an efficient translocation of folded proteins.