Simultaneous extraction of soil phytoavailable cadmium,copper, and lead by chelating resin membrane

Cadmium, copper, and lead were extracted from suspensions of contaminated soils using metal chelating exchange resin membranes. Nine soils with widely varying properties and Cd, Cu and Pb levels were tested. Soil suspensions made up with 4 g in 40 mL deionized water were equilibrated with 5 cm² Ca-saturated Chelex exchange resin membrane which was retained inside a polypropylene bag and shaken at 150 rpm for 24 hrs. Resin membrane extractable Cd, Cu and Pb of the soils were correlated with Cd, Cu, and Pb uptake by young wheat seedlings grown in these soils and compared with soil Cd, Cu, and Pb extracted by 0.1 M HCl, 0.01 M CaCl₂, and 0.005 M Diethylenetriamine pentaacetic acid (DTPA). The amounts of Cd, Cu and Pb extracted by the Ca-saturated Chelex membrane from all tested soils correlated well with those absorbed by young wheat seedlings. The Ca-saturated Chelex membrane extractable Cd, Cu and Pb of the soil had the strongest correlation with plant uptake Cd, Cu and Pb among the extraction methods we tested. It was demonstrated that the Ca-saturated Chelex membrane extraction is an appropriate method in simultaneously estimating Cd, Cu and Pb phytoavailability of soil and is applicable to a wide range of soils.     

Survival of Bifidobacterium longum Immobilized in Calcium Alginate Beads in Simulated Gastric Juices and Bile Salt Solution

Bifidobacterium longum KCTC 3128 and HLC 3742 were independently immobilized (entrapped) in calcium alginate beads containing 2, 3, and 4% sodium alginate. When the bifidobacteria entrapped in calcium alginate beads were exposed to simulated gastric juices and a bile salt solution, the death rate of the cells in the beads decreased proportionally with an increase in both the alginate gel concentration and bead size. The initial cell numbers in the beads affected the numbers of survivors after exposure to these solutions; however, the death rates of the viable cells were not affected. Accordingly, a mathematical model was formulated which expressed the influences of several parameters (gel concentration, bead size, and initial cell numbers) on the survival of entrapped bifidobacteria after sequential exposure to simulated gastric juices followed by a bile salt solution. The model proposed in this paper may be useful for estimating the survival of bifidobacteria in beads and establishing optimal entrapment conditions.     

Rb protein down-regulates the stress-activated signals through inhibiting c-Jun N-terminal kinase/stress-activated protein kinase

The Rb protein is the product of the retinoblastoma susceptibility gene and loss of Rb function is detected in many types of human cancers. Rb plays important roles in the regulation of cell proliferation, differentiation, senescence, and apoptotic cell death. Here we show that Rb can physically interact with c-Jun NH(2)-terminal kinase/stress-activated protein kinase (JNK/SAPK), thereby inhibiting intracellular signals mediated by JNK/SAPK. Both in vitro binding and in vitro kinase studies suggest that a carboxyl-terminal domain of Rb containing amino acids 768-928 might be crucial for inhibiting JNK/SAPK. In comparison, Rb did not affect enzymatic activity of either extracellular signal-regulated kinase 1 or p38. Ectopically expressed Rb also abrogated the apoptotic cell death induced by ultraviolet radiation or the activation of MEKK1, an upstream kinase that can stimulate the JNK/SAPK cascade. JNK/SAPK inhibition highlights a novel function of Rb, which may provide a new mechanism by which Rb regulates cell death. JNK/SAPK is a major protein kinase that can be stimulated in response to a variety of cellular stresses. Our results, therefore, suggest that Rb, by inhibiting JNK/SAPK, may act as a negative regulator in stress-activated intracellular signaling cascades.     

Muscle regulatory factor gene: zebrafish (Danio rerio) myogenin cDNA

Myogenin is one of the basic helix-loop-helix proteins that regulate muscle-specific gene expression. Using reverse transciption-polymerase chain reaction (RT-PCR), 5'- and 3'-rapid amplification of cDNA ends (RACE), zebrafish myogenin cDNA was cloned from mRNA of embryos at 10-96 h post-fertilization. The cDNA, at 1384 base pairs (bp), contained a 771-bp open reading frame with 113- and 500-bp flanking regions at the 5'- and 3'-ends, respectively. The deduced amino acid sequences of zebrafish myogenin encoded a 256-amino-acid polypeptide. In a comparison with myogenin of carp, trout, Xenopus, chicken and human, zebrafish myogenin shared 90.9, 77.6, 70.3, 62.9 and 51.5% amino acid identity, respectively. The basic helix-loop-helix domains in myogenin are all conserved. The molecular phylogenic tree demonstrated that myogenin of zebrafish is more closely related to that of fish than to the myogenin of other vertebrates.     

Mfd Dynamically Regulates Transcription via a Release and Catch-Up Mechanism

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VOCs-mediated hormonal signaling and crosstalk with plant growth promoting microbes

In the natural environment, plants communicate with various microorganisms (pathogenic or beneficial) and exhibit differential responses. In recent years, research on microbial volatile compounds (MVCs) has revealed them to be simple, effective and efficient groups of compounds that modulate plant growth and developmental processes. They also interfere with the signaling process. Different MVCs have been shown to promote plant growth via improved photosynthesis rates, increased plant resistance to pathogens, activated phytohormone signaling pathways, or, in some cases, inhibit plant growth, leading to death. Regardless of these exhibited roles, the molecules responsible, the underlying mechanisms, and induced specific metabolic/molecular changes are not fully understood. Here, we review current knowledge on the effects of MVCs on plants, with particular emphasis on their modulation of the salicylic acid, jasmonic acid/ethylene, and auxin signaling pathways. Additionally, opportunities for further research and potential practical applications presented.     

Long-term chemical castration induces depressive symptoms by suppressing serotonin expression in rats

Androgen deprivation therapy, also known as chemical castration, has been used as an adjunct to psychotherapy for sex offenders. Goserelin and bicalutamide are drugs used for chemical castration. Serotonin (5-hydroxytryptamine, 5-HT) is a key neurotransmitter involved in mood changes, such as depression. We investigated the effects of surgical and chemical castration on depressive symptoms in rats. Surgical castration was performed through a bilateral orchiectomy. Bicalutamide was administrated orally once a day for 84 consecutive days. Goserelin acetate was implanted subcutaneously into the anterior abdominal wall, and this implantation was repeated 3 times at 28-day intervals. Testosterone levels were detected by enzyme-linked immunosorbent assays. Sexual behaviors were analyzed by measuring mount latency, mount frequency, intromission latency, and intromission frequency. The forced swimming test was performed to evaluate rats’ depression status. To detect 5-HT and tryptophan hydroxylase (TPH)-positive cells in the dorsal raphe, immunohistochemistry for 5-HT and TPH and western blotting for 5-HT1A receptors and TPH were performed. Surgical castration and goserelin decreased testosterone levels and suppressed sexual behaviors. However, bicalutamide did not inhibit sexual behaviors, although it reduced testosterone levels to a limited extent. Both surgical and chemical castration induced depression in rats. The expression of 5-HT, TPH, and 5-HT1A receptors in the dorsal raphe was significantly decreased by both surgical castration and chemical castration via bicalutamide and goserelin. The present results showed that surgical and chemical castration for 12 weeks induced a depressive state in rats by inhibiting serotonergic function through 5-HT1A receptors.     

Pseudoparamoeba garorimi n. sp., with Notes on Species Distinctions within the Genus

A new marine species of naked lobose amoebae Pseudoparamoeba garorimi n. sp. (Amoebozoa, Dactylopodida) isolated from intertidal marine sediments of Garorim Bay, Korea was studied with light and transmission electron microscopy. This species has a typical set of morphological characters for a genus including the shape of the locomotive form, type of subpseudopodia and the tendency to form the single long waving pseudopodium in locomotion. Furthermore, it has the same cell surface structures as were described for the type species, Pseudoparamoeba pagei: blister‐like glycostyles with hexagonal base and dome‐shaped apex; besides, cell surface bears hair‐like outgrowths. The new species described here lacks clear morphological distinctions from the two other Pseudoparamoeba species, but has considerable differences in the 18S rDNA and COX1 gene sequences. Phylogenetic analysis based on 18S rDNA placed P. garorimi n. sp. at the base of the Pseudoparamoeba clade with high PP/BS support. The level of COX1 sequence divergence was 22% between P. garorimi n. sp. and P. pagei and 25% between P. garorimi n. sp. and P. microlepis. Pseudoparamoeba species are hardly distinguishable by morphology alone, but display clear differences in 18S rDNA and COX1 gene sequences.