Effects of supercritical CO2 exposure and depressurization on immobilized lipase activity

Lipozyme IM20 from Novo Nordisk (Denmark) was examined after various treatments. Conditions were chosen to reflect those that would be considered in the design of an industrial process. A two-level factorial design was employed to assess the effects of pressurization/depressurization cycles, rate of depressurization and exposure length. A significant three-factor interaction was observed. Lowest residual activity was observed for runs in which the depressurization rate was 86–89 bar min^–1. Incubation for 12 h also yielded low residual activity but only when exposing the immobilized enzyme to one cycle. The highest residual activity was obtained for immobilized enzymes repeatedly exposed for periods of 12 h (5 times) with a depressurization rate of 4.3 to 4.45 bar min^–1. This effect may be due to the extraction of an inhibiting compound. Tuning process parameters can lead to a seven-fold change in residual activity.     

Combined effects of food quantity and quality on Cd, Cr, and Zn assimilation to the green mussel, Perna viridis

We examined the assimilation of Cd, Cr, and Zn by the green mussel Perna viridis under complicated food conditions, including combinations of different compositions and concentrations of food (diatom and sediment), and variable food quantity and quality during particle digestion. At different combinations of food composition and quantity (5 mg l⁻¹ and 20 mg⁻¹, below and above the pseudofeces production), the Cd assimilation was significantly dependent on the food composition. The Cd assimilation efficiency (AE) decreased with increasing proportions of sediments in the diets, but its assimilation was not significantly affected by food concentration. In contrast, the assimilation of Cr and Zn decreased significantly with increasing food concentrations, whereas food composition did not significantly affect their AEs. Variations in metal gut passage time accounted partially for the difference in AEs among different combinations of food composition and quantity. By changing the type of particles during metal digestion, their AEs were maintained comparably at a low particle load (1 mg l⁻¹), suggesting that variation of food quality during digestion did not affect metal assimilation. At a higher particle load (5 mg l⁻¹), variation of food type during digestion affected the AEs of Cr and Zn. An increase in food concentrations from 1 to 15 mg l⁻¹ during digestion resulted in a significant decrease in the AEs of Cr and Zn bound with either sediments or diatoms. Conversely, decreasing the food concentrations from 15 to 1 mg l⁻¹ did not affect the AEs of metals, except for Zn bound with diatoms. Overall, our results highlighted the metal-specificity in their assimilation as influenced by complicated food environments, probably caused by different metal geochemical and biological behavior in the mussels. Feeding selectivity may have a greater control on the influx rate into the mussels than metal assimilation.     

Chaunopycnis pustulata sp. nov., a new clavicipitalean anamorph producing metabolites that modulate potassium ion channels

Two morphologically similar strains of hyphomycetous fungi, MF5785 and MF5638, produced potent indole diterpene antagonists of the calcium-gated potassium ion channel, Maxi-K, and a diterpene blocker (nalanthalide) of the voltage-gated potassium channel, Kv 1.3, respectively. The two strains were tentatively identified in the literature as Nalanthamala species. Analyses of their secondary metabolite profiles by HPLC and mass spectroscopy demonstrated that both produced a series of indole diterpenes, of which at least one was produced by both strains. Another strain, Chaunopycnis alba (MF6799), that produced the diterpene, nalanthalide, also produced indole diterpene metabolites. Morphological comparisons and phylogenetic studies based on 28S and ITS rDNA sequences indicated that MF5785 and MF5368, and another soil-derived strain GB6597, belonged to a monophyletic clade of the Clavicipitaceae that included the anamorph Chaunopycnis alba and several Cordyceps and Tolypocladium species. A new species of Chaunopycnis is therefore proposed to accommodate MF5785, MF5368, and GB6597. The possible synonymy of Albophoma yamanashiensis with C. alba also is discussed. Within the Clavicipitaceae, indole diterpenoid compounds have only been known from the graminicolous species (subfamily Clavicipitoideae); therefore delineation of a Chaunopycnis clade has revealed a previously unrecognized lineage of indole diterpene-producing fungi among the subfamily Cordycipitoideae.     

Isolation and characterization of microsatellite DNA markers in the malaria vector Anopheles funestus

Screening of the Anopheles funestus genomic DNA library detected 18 new sequences with dinucleotide tandem repeats. Primers were designed to amplify the loci and 14 out of 18 gave a repeatable and scorable amplification. Deviations from Hardy–Weinberg expectations were tested for each locus in a sample of 30 wild Anopheles funestus females. No heterozygote deficiency was detected for 11 loci of 14, thus revealing the absence of null alleles. The number of alleles per locus ranged from 5 to 15, and observed heterozygosity from 0.13 to 0.85.     

Efficient transient transformation of suspension culture-derived apple protoplasts

A protocol for comparatively efficient delivery of plasmid DNA into suspension culture-derived apple protoplasts is described. Increases in efficiency of transfection are achieved by elevating the temperature during protoplast exposure to the DNA. Two methods to detect transformed protoplasts are compared and the effectiveness and ease of application of flow cytometry techniques to this high throughput method is discussed.     

Cdc5 influences phosphorylation of Net1 and disassembly of the RENT complex

Background  

In S. cerevisiae, the mitotic exit network (MEN) proteins, including the Polo-like protein kinase Cdc5 and the protein phosphatase Cdc14, are required for exit from mitosis. In pre-anaphase cells, Cdc14 is sequestered to the nucleolus by Net1 as a part of the RENT complex. When cells are primed to exit mitosis, the RENT complex is disassembled and Cdc14 is released from the nucleolus.     

cDNA sequence of five mouse guanine deaminase (Gda) alleles and mapping to mouse chromosome 19.

Guanine deaminase catalyses the conversion of guanine to xanthine and ammonia, thereby irreversibly removing the guanine base from the pool of guanine-containing metabolites. We have identified five alleles at the mouse guanine deaminase locus by cDNA sequencing. These alleles were defined by single-nucleotide polymorphisms at a total of 19 positions. For each allele the representative strains are as follows: Gda(a), C57BL/6J and DBA/2J; Gda(b), A/J; Gda(c), MOLF/Ei; Gda(d), CAST/Ei; and Gda(e), SPRET-1. The only codon change resulting in an amino acid substitution was found at nucleotide 523, where GAT was replaced by AAT in Mus spretus resulting in the deduced substitution of Asp-174 by Asn. The single-nucleotide difference between the a and b alleles was also typed by allele-specific oligonucleotide amplification for 17 common strains of Mus musculus susbp. musculus. By typing the AxB and BxA recombinant inbred (RI) strain sets, Gda was mapped to mouse chromosome 19, a region syntenic with human chromosome 9q11-q22.     

Biofeedback Via Telehealth: A New Frontier for Applied Psychophysiology

Psychophysiological diagnostic and therapeutic methods, to include biofeedback, have been found to be empirically effective in the treatment of a variety of physical disorders. In many areas of the country, however, certified biofeedback practitioners are not well distributed, limiting patient access to this treatment modality. Psychologists at Tripler Army Medical Center have pioneered efforts to develop and provide these needed services via a telehealth venue. Such capability significantly improves access to care, particularly for patient's located at considerable distance from the provider. As the telecommunications infrastructure in rural and remote areas is often quite basic, such a system must be capable of operating within these limited parameters. The system developed by the authors provides real-time video and audio interactivity and allows the therapist to monitor and control biofeedback equipment located at the remote site. The authors discuss the clinical applications, the technology, and relevant practical and ethical issues.     

Enhanced production of free trans-astaxanthin by oxidative stress in the cultures of the green microalga Chlorococcum sp

Free trans-astaxanthin accumulated in the alga Chlorococcum sp. was markedly enhanced from 3.664 mg g⁻¹ cell dry weight to 5.724 mg g⁻¹ cell dry weight when the culture was supplemented with hydrogen peroxide (0.1 mM) under mixotrophic conditions of growth. After saponification, a total of 7.086 mg astaxanthin per g cell dry weight was achieved. Similarly, in heterotrophic cultures, the total astaxanthin content was increased from 1.034 mg g⁻¹ cell dry weight without H₂O₂ to 1.782 mg g⁻¹ cell dry weight with 0.1mM H₂O₂. Results indicate that hydrogen peroxide effectively induces the formation of free trans-astaxanthin in Chlorococcum sp.