Contact inhibition in colony formation

Contact inhibition of replication of the established mammalian cell line 3T3 was examined during growth of the colony and compared with that of the Chinese-hamster cell line CHL-1. The growth curves of cells in the colonies conformed to the predicted exponential and linear rates for CHL-1 and 3T3 respectively. Autoradiographs of colonies in which DNA was labeled with tritiated thymidine showed that in 3T3 colonies, only peripheral cells were labeled, while CHL-1 colonies were labeled throughout.     

Late Pleistocene Desiccation of Lake Victoria and Rapid Evolution of Cichlid Fishes

Lake Victoria is the largest lake in Africa and harbors more than 300 endemic species of haplochromine cichlid fish. Seismic reflection profiles and piston cores show that the lake not only was at a low stand but dried up completely during the Late Pleistocene, before 12,400 carbon-14 years before the present. These results imply that the rate of speciation of cichlid fish in this tropical lake has been extremely rapid.     

Improved subtilisin YaB production in Bacillus subtilis using engineered synthetic expression control sequences

Alkaline elastase YaB, a favorable meat tenderizer, is an extracellular subtilisin-type protease produced by wild strain alkalophilic Bacillus YaB. The gene ale coding for subtilisin YaB with its own expression control sequence has been cloned and expressed in Bacillus subtilis, but at levels much lower than in the parental strain Bacillus YaB. This study investigates the influence of various expression control sequences including expression control sequences of cdd and veg from B. subtilis, a synthetic expression control sequence (SECS), and engineered synthetic expression control sequences (engineered SECSs) on the expression of subtilisin YaB in B. subtilis. The engineered SECSs were generated by using the Polymerase Chain Reaction; their UP element, Shine-Dargarno (SD) sequence, or both were different from those of the native SECS. The expression efficiencies of SECS and engineered SECSs were higher than those of expression control sequences of ale, cdd, and veg. Substitution of the SD sequence of SECS resulted in higher expression of subtilisin YaB than substitution of the UP element, whereas combined substitution of both gave the highest expression. These results demonstrate that engineering of SECSs is an approach for improving subtilisin YaB production in B. subtilis. Moreover, it is suggested that these enginnered SECSs could potentially be used to express homologous and heterologous proteins in B. subtilis at high level.     

Activity- and mTOR-dependent suppression of Kv1.1 channel mRNA translation in dendrites

Mammalian target of rapamycin (mTOR) is implicated in synaptic plasticity and local translation in dendrites. We found that the mTOR inhibitor, rapamycin, increased the Kv1.1 voltage-gated potassium channel protein in hippocampal neurons and promoted Kv1.1 surface expression on dendrites without altering its axonal expression. Moreover, endogenous Kv1.1 mRNA was detected in dendrites. Using Kv1.1 fused to the photoconvertible fluorescence protein Kaede as a reporter for local synthesis, we observed Kv1.1 synthesis in dendrites upon inhibition of mTOR or the N-methyl-d-aspartate (NMDA) glutamate receptor. Thus, synaptic excitation may cause local suppression of dendritic Kv1 channels by reducing their local synthesis.     

Antifungal agents from heartwood extract of <Emphasis Type="Italic">Taiwania cryptomerioides</Emphasis> against brown root rot fungus <Emphasis Type="Italic">Phellinus noxius</Emphasis>

Taiwania (Taiwania cryptomerioides Hayata) is a native and plantation species in Taiwan, and its heartwood has demonstrated excellent decay resistance. Brown root rot fungus Phellinus noxius has caused severe damage to more than 100 tree species in Taiwan. The aims of this study were to investigate the antifungal activities of Taiwania heartwood extracts against P. noxius and to identify the antifungal compounds. Antifungal activities were examined using the agar dilution method (a direct contact assay) and the inverted lid method (a vapor contact assay). Active compounds were purified using liquid–liquid partition, open-column chromatography and HPLC. Among four soluble fractions (n-hexane, ethyl acetate, n-butanol and water soluble fractions), results showed that n-hexane soluble fraction (HSF) can significantly inhibit the growth of P. noxius via the agar dilution method. Moreover, active compounds present in HSF were obtained using antifungal assay-guided fractionation. Results showed that ferruginol, T-cadinol, α-cadinol and T-muurolol were found to exhibit excellent antifungal activities against P. noxius, and their IC₅₀ values were 16.9, 25.8, 33.8 and 50.6 μg/mL, respectively. According to the current findings, phytochemicals (ferruginol, T-cadinol, α-cadinol and T-muurolol) of Taiwania heartwood had the potential to be used as environmentally benign antifungal agents against P. noxius in place of synthetic or inorganic fungicides.     

Animal Health Policy Principles for Highly Pathogenic Avian Influenza: Shared Experience from China and Canada

Animal health policy for highly pathogenic avian influenza (HPAI) must, for the time being, be based on expert opinion and shared international experience. We used the intellectual capital and knowledge of experienced Chinese and Canadian practitioners and policy makers to inform policy options for China and find shared policy elements applicable to both countries. No peer‐reviewed comprehensive evaluations or systematic regulatory impact assessments of animal health policies were found. Sixteen guiding policy principles emerged from our thematic analysis of Chinese and Canadian policies. We provide a list of shared policy goals, targets and elements for HPAI preparedness, response and recovery. Policy elements clustered in a manner consistent with core public health competencies. Complex situations like HPAI require complex and adaptive policies, yet policies that cross jurisdictions and are fully integrated across agencies are rare. We encourage countries to develop or deploy capacity to undertake and publish regulatory impact assessments and policy evaluation to identify policy needs and provide a basis for evidence‐based policy development.     

Different central manifestations in response to electroacupuncture at analgesic and nonanalgesic acupoints in rats: a manganese-enhanced functional magnetic resonance imaging study

Acupuncture analgesia is an important issue in veterinary medicine. This study was designed to elucidate central modulation effects in response to electroacupuncture (EA) at different acupoints. Manganese-enhanced functional magnetic resonance imaging was performed in Sprague-Dawley rats after sham acupuncture, sham EA, or true EA at somatic acupoints. The acupoints were divided into 3 groups: group 1, analgesic acupoints commonly used for pain relief, such as Hegu (LI 4); group 2, nonanalgesic acupoints rarely used for analgesic effect, such as Neiguan (PC 6); and group 3, acupoints occasionally used for analgesia, such as Zusanli (ST 36). Image acquisition was performed on a 1.5-T superconductive clinical scanner with a circular polarized extremity coil. The results showed that there was no neural activation caused by EA at a true acupoint with shallow needling and no electric current (sham acupuncture). When EA at a true acupoint was applied with true needling but no electric current (sham EA), there was only a slight increase in brain activity at the hypothalamus; when EA was applied at a true acupoint with true needling and an electric current (true EA), the primary response at the hypothalamus was enhanced. Also, there was a tendency for the early activation of pain-modulation areas to be prominent after EA at analgesic acupoints as compared with nonanalgesic acupoints. In conclusion, understanding the linkage between peripheral acupoint stimulation and central neural pathways provides not only an evidence-based approach for veterinary acupuncture but also a useful guide for clinical applications of acupuncture.     

Effect of Amylose Content on Expansion of Extruded Rice Pellet

Rice pellets were prepared by single‐screw extrusion cooking with an in‐barrel water content of 50 wt%. Three different types of rice, indica glutinous, japonica, and indica, were used as raw materials. Reconstituted rice flour was made to study the effect of amylose content on pellet expansion. The glass transition (T_g) and expansion (T_e) temperatures of extruded pellet were determined by differential scanning calorimetry (DSC) and noncontact infrared thermometer, respectively. The amylose content was not significantly affected by extrusion cooking. The reduction in intrinsic viscosity indicated that amylopectin experienced some degradation. The T_g and T_e were not functions of amylose content, which affected the expansion ratio of the pellets. The Gordon‐Taylor equation was applied to estimate the T_g of the rice pellets.     

Molecular and Gelatinization Properties of Rice Starches from IR24 and Sinandomeng Cultivars

The differences in pasting properties involving gelatinization and retrogradation of rice starches from IR24 and Sinandomeng cultivars during heating‐cooling processes were investigated using a Rapid Visco Analyser (RVA)and a dynamic rheometer. The results were discussed in relation to the molecular structure, actual amylose content (AC), and concentration of the starches. Generally, both starches possessed a comparable AC (≈11 wt%), amylose average chain length (CL), iodine absorption properties, and dynamic rheological parameters on heating to 95°C at 10 wt% and on cooling to 10°C at higher concentrations. In contrast to Sinandomeng, IR24 amylose had a greater proportion of high molecular weight species and number‐average degree of polymerization (DP_n). IR24 amylopectin possessed a lower DP_n and greater CL, exterior CL (ECL), and interior CL (ICL). Comparing the results of RVA analysis and dynamic rheology, the gelatinization properties and higher retrogradation tendencies of IR24 starch can be related to the structural properties and depend on starch concentration. In addition, the exponent n of starch concentration for storage moduli at 25°C (G′₂₅ ∝ Cⁿ) increased linearly with increasing AC.