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[Comparative study on immune enhancement effects of four kinds of dodder seeds in Shandong Province].

OBJECTIVE: To compare the effects of immune enhancement, anti-fatigue and anoxia tolerance on mice of four kinds of dodder seeds in Shandong Province. METHODS: Water extracts and alcohol extracts of the four kinds of dodder seeds were administered to mice. The phagocytosis of coelio-macrophage, the weight changes of the immune organs, the survival time to swimming and lacking of oxygen were observed. RESULTS: The four kinds of dodder seeds in Shandong Province could enhance the phagocytosis of macrophage of mice and increase the weights of thymus and spleen of the immature mice. They could prolong the survival time of mice swimming and lacking oxygen. Cuscuta chinensis Lam. and C. australis R. Br. had better effects than the other two kinds, and the water extracts had better effects than alcohol extracts. CONCLUSION: The four kinds of dodder seeds in Shandong Province have the effects of immune enhancement, anti-fatigue and anoxia tolerance. The polysaccharide in dodder seeds is one of the effective materials to improve the immune system.

Animals↗

Fabrication and evaluation of a new composite composed of tricalcium phosphate, gelatin, and Chinese medicine as a bone substitute.

This study investigates the biological effects of traditional Chinese medicines on the activities of bone cells using rat bone cells. Then, a mixture of a GGT composite, that is, a novel biodegradable composite containing genipin crosslinked gelatin and tricalcium phosphate, and traditional Chinese medicine (TCM) was prepared as a GGT-TCM composite. A cultured neonatal rat calvarias organ was used to measure the potential of GGT-TCM composite for use in promoting the regeneration of defective bone tissue. The mitochondria activity of the bone cells following exposure to various concentrations of crude extracts of five herbal Chinese medicines was measured by colorimetric assay. Biochemical markers, such as alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) titers were analyzed to evaluate the activities of bone cells. Finally, we examined the organ culture units, which were maintained in cultured medium for 5 weeks. Morphology of tissue was observed, and the quantitative evaluation of the regenerated bone was determined. In a bone cells culture experiment, adding Cuscuta chinensis Lam. (TCM-5) to the bone cells culture clearly promoted the proliferation and differentiation of the osteoblasts from their precursor cells; but the reduced amount of TRAP indicated that the medicine significantly inhibited the osteoclasts activities. Opposite bone cell responses were observed when Loranthus parasiticus Merr. (TCM-3) and Achyranthes bidentata Bl. (TCM-4) were added to the bone cells culture. Eucommia ulmoides Oliv. (TCM-1) and Dipsacus asper Wall. (TCM-2) potentially influence the proliferation and differentiation of the osteoblasts from their precursor cells, but they did not affect the osteoclasts activities. The finding from the organ culture indicated that Chinese medicine effectively increased the rate of tissue regeneration of damaged bones.

Acid Phosphatase↗

The effectiveness of plant conservation: a case study of Opole Province, southwest Poland.

This work presents a method of assessing plant conservation effectiveness in a given region, which takes into account the legal, species-centered protection, ecosystem conservation, ex situ conservation, restorations and translocations, reintroductions, and monitoring. In order to illustrate the conservation effectiveness, both legally protected species of plants and threatened species were examined. The conservation effectiveness of legally protected species was estimated to have a low value of 23.328 points (pts) according to the methods of calculation. Habitat conservation is insufficient for these species. Almost 40% of all localities are deprived of any ecosystem protection. The conservation effectiveness of the threatened group of species scored a very low value of 13.46 pts. The major reason for this result is a very low level of species protection. Less than 30% of the threatened taxa are under legal preservation and some species from the Orobanche and Cuscuta genera are treated as harmful organisms, which it is obligatory to control within the province territory. Almost 30% of all localities of threatened species are deprived of any ecosystem protection and only 10% lie inside nature reserves. It is suggested that the conclusion of this investigation be used in the preparation and realization of the regional floristic diversity preservation strategy.

Conservation of Natural Resources↗

Direct and ecological costs of resistance and tolerance in the stinging nettle.

Plant resistance and tolerance to herbivores, parasites, pathogens, and abiotic factors may involve two types of costs. First, resistance and tolerance may be costly in terms of plant fitness. Second, resistance and tolerance to multiple enemies may involve ecological trade-offs. Our study species, the stinging nettle ( Urtica dioicaL.) has significant variation among seed families in resistance and tolerance as well as costs of resistance and tolerance to the holoparasitic plant Cuscuta europaea L. Here we report on variation among seed families (i.e. genetic) in tolerance to nutrient limitation and in resistance to both mammalian herbivores (i.e. number of stinging trichomes) and an invertebrate herbivore (i.e. inverse of the performance of a generalist snail, Arianta arbustorum). Our results indicate direct fitness costs of snail resistance in terms of host reproduction whereas we did not detect fitness costs of mammalian resistance or tolerance to nutrient limitation. We further tested for ecological trade-offs among tolerance or resistance to the parasitic plant, herbivore resistance, and tolerance to nutrient limitation in the stinging nettle. Tolerance of nettles to nutrient limitation and resistance to mammalian herbivores tended to correlate negatively. However, there were no significant correlations among resistance and tolerance to the different natural enemies (i.e. parasitic plants, snails, and mammals). The results of this greenhouse study thus suggest that resistance and tolerance of nettles to diverse enemies are free to evolve independently of each other but not completely without direct costs in terms of plant fitness.

Adaptation, Physiological↗

Neuroprotective effect of a chuk-me-sun-dan on neurons from ischemic damage and neuronal cell toxicity.

Chukmesundan (CMSD), composed of the following 8 medicinal herbs including Panex ginseng C.A. MEYER, Atractylodes macrocephala KOID, Poria cocos WOLF, Pinellia ternata BREIT, Brassica alba BOISS, Aconitum carmichaeli DEBX, Cynanchum atratum BGE and Cuscuta chinensis LAM. CMSD is being used in Korea for the treatment of various symptoms accompanying hypertension and cerebrovascular disorders. This study was carried out to examine the effects of CMSD on cultured primary neuron cell, cell cytotoxicity and lipid peroxidation in Abeta-treated cells. Cell death was enhanced by addition of Abeta. Pretreatment of CMSD attenuated in cell killing induced by Abeta. The protective effect of the CMSD water extracts on Abeta-induced neuronal death was also observed by lactate dehydrogenase assay using cultured astrocyte cells. Abeta-induced cell death was protected by the water extract of CMSD in a dose-dependent manner, and 25-50 microg/ml was the most effective concentration. CMSD has been also shown to protect primary cultured neurons from N-methyl-D: -aspartate receptor-mediated glutamate toxicity. It was in vivo evidenced that CMSD protects neurons against ischemia-induced cell death. Moreover, oral administration of CMSD into mice prevented ischemia-induced learning disability and rescued hippocampal CA1 neurons from lethal ischemic damage. The neuroprotective action of exogenous CMSD was also confirmed by counting synapses in the hippocampal CA1 region. The presence of CMSD in neuron cultures rescued the neurons from nitrogen oxide (NO)-induced death. From these, it was suggested that CMSD may exert its neuroprotective effect by reducing the NO-mediated formation of free radicals or antagonizing their toxicity.

Amyloid beta-Peptides↗

Calystegines as chemotaxonomic markers in the Convolvulaceae.

An extended GC-MS study of 129 convolvulaceous species belonging to 29 genera (all 12 tribes) including the results of a previous survey (65 spp.) revealed the occurrence of one to six polyhydroxy alkaloids of the nortropane type (calystegines) in 62 species belonging to 22 genera of all tribes except the unique parasitic Cuscuteae. The large genus Ipomoea turned out to comprise calystegine-positive species in at least eight out of ten sections checked. The number of the calystegines used as reference compounds has been increased from seven (previous survey) to 11 (present study). Furthermore, the results concerning these additional four alkaloids could also be completed for all species of the previous survey. The plant material (epigeal vegetative parts and/or roots, flowers, fruits/seeds) was obtained from collections in the wild from a wide range of tropical, subtropical, and temperate locations of all continents as well as from cultivation in the greenhouse. All plant organs turned out to be potential locations for the occurrence of these metabolites though they are detectable often only in certain organs of a given species. Three genera (Cuscuta, Operculina, Polymeria) might have lost the ability to synthesize these plesiomorphic characters in the course of the evolution since the examination of several different organs and/or provenances of five species each failed to show calystegines as constituents. Nevertheless, the present data clearly demonstrate that the occurrence of calystegines is an almost consistent trait in the Convolvulaceae in principle, from basal to most advanced tribes.

Alkaloids↗

Immunomodulatory effects of C3bgp on the antibody response to hemocyanin in outbred rabbits and the F1 generation of breeding with siblings.

Dynamics and quantitative analyses of monospecific antibody during the primary and secondary humoral responses were determined in outbred rabbits and in the F1 generation of breeding with siblings. The antibody response in rabbits immunized with Keyhole Limpet Hemocyanin (KLH) was studied during a 4-month immunization period. ELISA determination of anti-KLH Ig and anti-KLH IgG alone, in preimmune and immune rabbit sera, was performed. Antibody response in both groups of rabbits was similar when assessed by anti-rabbit Ig but displayed differences when assessed by anti-rabbit IgG. A statistically significant increase in anti-KLH IgG was observed in the F1 inbred rabbits compared to the control group after primary immunization from days 14 to 35. Immunomodulation also elicited differences in the antibody response in the two groups of animals. C3-binding glycoprotein isolated from Cuscuta europea (C3bgp), applied simultaneously with antigen (KLH), produced a much stronger secondary immune response than the antigen alone, in both experimental groups. The enhancement of anti-KLH Ig in C3bgp-treated inbred rabbits was statistically significant in comparison with nontreated inbred rabbits. A significant increase in anti-KLH IgG was observed only for the inbred group after treatment with C3bgp. The results demonstrate that the F1 generation of breeding with sibling leads to significant differences in antibody responses to immunization compared with outbred rabbits, as well as to immunomodulation with C3bgp.

Animals↗

Antimutagenicity of some edible Thai plants, and a bioactive carbazole alkaloid, mahanine, isolated from Micromelum minutum.

The antimutagenic activity against Trp-P-1 of methanolic extracts of 118 samples (108 species) of edible Thai plants was examined by the Ames Test. The activity was evaluated by the amount of plant extracts which suppressed 90% of the mutagenesis (ED90). Five plants, Micromelum minutum, Oroxylum indicum, Cuscuta chinensis, Azadirachta indica, and Litsea petiolata, exhibited significant activity with antimutagenic ED90 values lower than 5 microL/plate (0.1 mg of dry plant material equivalent). The activity-guided fractionation of the extract of M. minutum, which exhibited the highest antimutagenic activity in the screening, resulted in the isolation of an active principle, (+)-mahanine (1) as confirmed by its physicochemical properties. Compound 1 showed a wide variety of biological activity, including antimutagenicity against heterocyclic amines such as Trp-P-1 with an IC50 of 5.2 microM, cytotoxicity against a tumor cell line HL60 with a MIC100 of 4.0 microg/mL, and antimicrobial activity against Bacillus cereus and Staphylococcus aureus with MIC100 values of 6.25 and 12.5 microg/mL, respectively.

Anti-Bacterial Agents↗

Alternate paths of evolution for the photosynthetic gene rbcL in four nonphotosynthetic species of Orobanche.

We have determined the nucleotide sequence for the Rubisco large subunit from four holoparasitic species of Orobanche. Intact open reading frames are present in two species (O. corymbosa and O. fasciculata), whereas the remaining species (O. cernua and O. ramosa) have rbcL pseudogenes. Sequences for rbcL 5'-UTRs from species of Orobanche have few changes in the promoter and ribosome binding sites compared to photosynthetic higher plants. Comparison of rbcL 3'-UTR sequences for Nicotiana, Ipomoea, Cuscuta, and Orobanche reveal that nucleotide sequences from parasitic plants have regions capable of forming stem-loop structures, but 56-69 nt are deleted upstream of the stem-loop in the parasitic plants compared to their photosynthetic relatives. Although rbcL pseudogenes of O. cernua and O. ramosa have many large and small deletions, few indels are shared in common, implying that their common ancestor probably had an intact rbcL reading frame. Intact rbcL reading frames in O. corymbosa and O. fasciculata retain a bias of synonymous over nonsynonymous substitutions and deduced protein sequences are consistent with potentially functional Rubisco large subunit proteins. A conservative model of random substitution processes in pseudogene sequences estimates that the probability is low (P < 0.028) that these sequences would retain an open reading frame by chance. Species of Orobanche have either had recent photosynthetic ancestors, implying multiple independent losses of photosynthesis in this genus, or the rbcL gene may serve an unknown function in some nonphotosynthetic plants.

Amino Acid Sequence↗

Population structure of a parasitic plant and its perennial host.

Characterization of host and parasite population genetic structure and estimation of gene flow among populations are essential for the understanding of parasite local adaptation and coevolutionary interactions between hosts and parasites. We examined two aspects of population structure in a parasitic plant, the greater dodder (Cuscuta europaea) and its host plant, the stinging nettle (Urtica dioica), using allozyme data from 12 host and eight parasite populations. First, we examined whether hosts exposed to parasitism in the past contain higher levels of genetic variation. Second, we examined whether host and parasite populations differ in terms of population structure and if their population structures are correlated. There was no evidence that host populations differed in terms of gene diversity or heterozygosity according to their history of parasitism. Host populations were genetically more differentiated (F(ST) = 0.032) than parasite populations (F(ST) = 0.009). Based on these F(ST) values, gene flow was high for both host and parasite. Such high levels of gene flow could counteract selection for local adaptation of the parasite. We found no significant correlation between geographic and genetic distance (estimated as pairwise F(ST)), either for the host or for the parasite. Furthermore, host and parasite genetic distance matrices were uncorrelated, suggesting that sites with genetically similar host populations are unlikely to have genetically similar parasite populations.

Alleles↗

Unusual carotenoid composition and a new type of xanthophyll cycle in plants.

The capture of photons by the photosynthetic apparatus is the first step in photosynthesis in all autotrophic higher plants. This light capture is dominated by pigment-containing proteins known as light-harvesting complexes (LHCs). The xanthophyll-carotenoid complement of these LHCs (neoxanthin, violaxanthin, and lutein) is highly conserved, with no deletions and few, uncommon additions. We report that neoxanthin, considered an integral component of LHCs, is stoichiometrically replaced by lutein-5,6-epoxide in the parasitic angiosperm Cuscuta reflexa, without compromising the structural integrity of the LHCs. Lutein-5,6-epoxide differs from neoxanthin in that it is involved in a light-driven deepoxidation cycle similar to the deepoxidation of violaxanthin in the xanthophyll cycle, which is implicated in protection against photodamage. The absence of neoxanthin and its replacement by lutein-5,6-epoxide changes our understanding of the structure-function relationship in LHCs, has implications for biosynthetic pathways involving neoxanthin (such as the plant hormone abscisic acid), and identifies one of the early steps associated with the evolution of heterotrophy from autotrophy in plants.

Journal Article↗

Neuroprotective effect of Chuk-Me-Sun-Dan on NMDA- and AMPA-evoked nitric oxide synthase activity in mouse brain.

Chukmesundan (CMSD) is composed of 8 medicinal herbs including Panex ginseng C.A. MEYER, Atractylodes macrocephala KOID, Poria cocos WOLF, Pinellia ternata BREIT, Brassica alba BOISS, Aconitum carmichaeli DEBX, Cynanchum atratum BGE, and Cuscuta chinensis LAM and used for the treatment of various symptoms accompanying hypertension and cerebrovascular disorders. This study was carried out to examine the effects of CMSD on N-methyl-D-aspartate (NMDA)-evoked, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-evoked nitric oxide synthase (NOS) activity in mouse brain. In adult forebrain, CMSD influences neuronal maintenance and is neuroprotective in several injury models through mechanisms that are incompletely understood. Interaction is observed between CMSD and nitric oxide (NO). Because NO affects both neural plasticity and degeneration, we hypothesized that CMSD might rapidly modulate NO production. Using in vivo microdialysis we measured conversion of L-[14C] arginine to L-[14C] citrulline as an accurate reflection of NOS activity in adult mouse hippocampus. CMSD significantly reduced NOS activities to 62% of basal levels within 2 days of onset of delivery and maintained NOS activity at less than 45% of baseline throughout 3 days of delivery. These effects did not occur with control (distilled water) and were not mediated by effect of CMSD on glutamate levels. In addition, simultaneous delivery of CMSD treatment prevented significant increases in NOS activity triggered by the glutamate receptor agonists NMDA and AMPA. Rapid suppression by CMSD of basal and glutamate-stimulated NOS activity may regulate neuromodulatory functions of NO or protect neurons from NO toxicity and suggests a novel mechanism for rapidly mediating functions of CMSD. It is shown that NMDA receptor stimulation leads to activation of p21ras (Ras) through generation of NO via neuronal NOS. The competitive NOS inhibitor, L-nitroarginine methyl ester, and CMSD prevents Ras activation elicited by NMDA, thus supporting the physiologic relevance of endogenous NO regulation of Ras. These results suggest that Ras is a physiologic target of endogenously produced NO and indicates a signaling pathway for NMDA receptor activation that may be important for long-lasting neuronal responses.

Animals↗

Circulating immune complexes among diabetic children.

Insulin dependent diabetes mellitus (IDDM) is an autoimmune disease associated with the presence of different types of autoantibodies. The presence of these antibodies and the corresponding antigens in the circulation leads to the formation of circulating immune complexes (CIC). CIC are known to persist in the blood for long periods of time. Such CIC following deposition in the small blood vessels have the potential to lead to microangiopathy with debilitating clinical consequences. The aim of our pilot study was to investigate whether a correlation exists between CIC and the development of microvascular complications in diabetic children. Isolation of a new glycoprotein complement inhibition factor (CIF) from the parasitic plant Cuscuta europea seed, which appears to bind specifically to complement component C3 has provided an unique tool for the measurement of immune complexes by means of ELISA-type techniques (CIF-ELISA). We studied the levels of CIC (IgG, IgM and IgA) in 58 diabetic children (mean age 12.28 +/- 4.04 years, diabetes duration 5.3 +/- 3.7 years), 29 of them had vascular complications (group 1) and the other 29 were without vascular complications (group 2). As controls, we studied sera samples from 21 healthy children (mean age 13.54 +/- 4.03 years). Sera from the diabetic patients showed statistically significant higher levels of CIC IgG (p = 0.03) than sera from the control group. In sera from group 1 values of CIC IgG showed statistically significant higher levels than controls (0.720 +/- 0.31 vs. 0.46 +/- 0.045; p = 0.011) Sera from 59% of the patients were positive for CIC IgG, 36% for CIC IgM and 9% for CIC IgA. Among 26 patients with microalbuminuria, sera from 17/26 (65%) were positive for CIC IgG, 8/26 (31%) for CIC IgM and 2/26 (8%) for CIC IgA. CIC IgG correlated with HbAlc (r = 0.51; p = 0.005) and microalbuminuria (r = 0.42, p = 0.033). CIC IgA correlated with age (r = 0.44, p = 0.03). CIC IgM correlated with the duration of diabetes (r = 0.63, p = 0.02). These findings suggest that elevated levels of CIC IgG are associated with the development of early diabetic nephropathy.

Adolescent↗

Dodder infection induces the expression of a pathogenesis-related gene of the family PR-10 in alfalfa.

A full-length cDNA, PPRG2, representing a gene highly expressed in dodder (Cuscuta trifolii Bab et. Gibs)-infected alfalfa (Medicago sativa L.) stems was isolated by differential screening. The predicted protein contains 157 amino acids and belongs to the PR-10 family of the pathogenesis-related genes with putative ribonuclease activities. Northern hybridizations showed that PPRG2 is transcribed in root and crops of uninfected alfalfa and is induced not only by dodder attack but also by bacterial infections and a large variety of environmental stresses.

Bacteria↗

Ethnomedicines used in Trinidad and Tobago for urinary problems and diabetes mellitus.

BACKGROUND: This paper is based on ethnobotanical interviews conducted from 1996-2000 in Trinidad and Tobago with thirty male and female respondents. METHODS: A non-experimental validation was conducted on the plants used for urinary problems and diabetes mellitus: This is a preliminary step to establish that the plants used are safe or effective, to help direct clinical trials, and to inform Caribbean physicians of the plants' known properties to avoid counter-prescribing. RESULTS: The following plants are used to treat diabetes: Antigonon leptopus, Bidens alba, Bidens pilosa, Bixa orellana, Bontia daphnoides, Carica papaya, Catharanthus roseus, Cocos nucifera, Gomphrena globosa, Laportea aestuans, Momordica charantia, Morus alba, Phyllanthus urinaria and Spiranthes acaulis. Apium graviolens is used as a heart tonic and for low blood pressure. Bixa orellana, Bontia daphnoides, Cuscuta americana and Gomphrena globosa are used for jaundice. The following plants are used for hypertension: Aloe vera, Annona muricata, Artocarpus altilis, Bixa orellana, Bidens alba, Bidens pilosa, Bonta daphnoides, Carica papaya, Cecropia peltata, Citrus paradisi, Cola nitida, Crescentia cujete, Gomphrena globosa, Hibiscus sabdariffa, Kalanchoe pinnata, Morus alba, Nopalea cochinellifera, Ocimum campechianum, Passiflora quadrangularis, Persea americana and Tamarindus indicus. The plants used for kidney problems are Theobroma cacao, Chamaesyce hirta, Flemingia strobilifera, Peperomia rotundifolia, Petiveria alliacea, Nopalea cochinellifera, Apium graveolens, Cynodon dactylon, Eleusine indica, Gomphrena globosa, Pityrogramma calomelanos and Vetiveria zizanioides. Plants are also used for gall stones and for cooling. CONCLUSION: Chamaesyce hirta, Cissus verticillata, Kalanchoe pinnata, Peperomia spp., Portulaca oleraceae, Scoparia dulcis, and Zea mays have sufficient evidence to support their traditional use for urinary problems, "cooling" and high cholesterol. Eggplant extract as a hypocholesterolemic agent has some support but needs more study. The plants used for hypertension, jaundice and diabetes that may be safe and justify more formal evaluation are Annona squamosa, Aloe vera, Apium graveolens, Bidens alba, Carica papaya, Catharanthus roseus, Cecropia peltata, Citrus paradisi, Hibsicus sabdariffa, Momordica charantia, Morus alba, Persea americana, Phyllanthus urinaria, Tamarindus indicus and Tournefortia hirsutissima. Several of the plants are used for more than one condition and further trials should take this into account.

Diabetes Mellitus↗

Effect of SA1, a herbal formulation, on sexual behavior and penile erection.

SA1 is a mixture of 9 Oriental herbs (Korean red ginseng, fermented soybean, Tribulus terrestris, Fructus Rubi, Fructus Lycii, Semen Cuscutae, Dioscorea Rhizome, Fructus Corni and Fructus Crataegi) that are widely used as energizers and vitalizers in the indigenous system of medicine and have been alleged to improve the sexual functions in men. This study evaluated SA1 using both in vitro and in vivo experiments on laboratory animals in order to determine its effect on the sexual behavior and penile erection. The male rats used to examine the copulatory behavior were administered either the vehicle or SA1 (30, 100, 300, 600 mg/kg) orally for 2 weeks. The intracavernous pressure and systemic blood pressure were recorded in anesthetized rats. The responses to acetylcholine and SA1 of rabbit corpus cavernosum strips were also examined. There was an overall increase in the copulatory behavior parameters in the SA1-treated rats, which was reflected by a decrease in the mount and intromission latencies and an increase in the ejaculation latency and mount frequency. SA1 significantly increased the ratio of the intracavernous pressure to mean arterial pressure. In vitro, SA1 significantly enhanced the relaxation responses to acetylcholine. These results suggest that SA1 improves the sexual activity and erectile function.

Animals↗

Protective effects of Chinese herbs on D-galactose-induced oxidative damage.

A mixture of traditional Chinese herbs ('FTDA') was found to improve several oxidation-related biomarkers in D-galactose-induced mimetic aging mice. FTDA consists of seven herbal components: Cuscutae Semen, Schisandrae Fructus, Dioscoreae Rhizoma, Lonicerae Flos, Nelumbinis Semen, Angelica Radix and Poria, and is routinely used for treating mice with D-galactose-induced oxidative damage. Measurements of antioxidant status, including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant status (TAS) and malondialdehyde (MDA) were made on blood, brain and liver tissue collected from animals after 60 days of treatment with D-galactose subcutaneous injections. High-dose, medium-dose and control groups exhibited higher levels of SOD, GSH-Px and TAS in their blood, as well as lower levels of serum MDA activity, compared with the D-galactose group. In the liver, all three experimental and PBS groups demonstrated significant increases in SOD activity and a decrease in MDA activity. The MDA activity decreased in medium-dose, high-dose and PBS groups, while medium-dose and PBS groups demonstrated increased SOD activity compared with that seen in the brain. These results support the efficacy of FTDA in improving the antioxidant status of D-galactose-induced mimetic aging mice.

Animals↗

Spectroscopic detection of a phytochrome-like photoreceptor in the myxomycete Physarum polycephalum and the kinetic mechanism for the photocontrol of sporulation by Pfr.

Sporulation of the true slime mold Physarum polycephalum (Myxomycetales) can be triggered by the far-red/red reversible Physarum phytochrome. Physarum plasmodia were analyzed with a purpose-built dual-wavelength photometer that is designed for phytochrome measurements. A photoreversible absorbance change at 670 nm was monitored after actinic red (R) and far-red (FR) irradiation of starved plasmodia, confirming the occurrence of a phytochrome-like photoreceptor in Physarum spectroscopically. These signals were not found in growing plasmodia, suggesting the Physarum phytochrome to be synthesized during starvation, which makes the cells competent for the photoinduction of sporulation. The photoconversion rates by R and FR light were similar in the phytochromes of Physarum and etiolated oat shoots. In dark-grown Physarum plasmodia that had not been preexposed to any light only R induced a detectable absorbance change while FR did not. This indicates that most (at least 90%) of the photoreversible pigment occurs in the red-absorbing form. Since the effectiveness of FR in triggering sporulation was enhanced by preirradiation with R, it is concluded that at least part of the Pr can be photoconverted to the active Pfr photoreceptor species. We propose a kinetic mechanism for the photocontrol of sporulation by photoconversion of Pfr, which may also hold for the high-irradiance response to FR in Arabidopsis and Cuscuta.

Animals↗