Influence of cadmium on the distribution of the essential trace elements zinc and copper in the liver and kidneys of rats

Cd induced changes of Zn and Cd distribution in the liver and kidneys were studied in relation to Cd metallothionein (MT) synthesis. Wistar male rats were given CdCl₂ by sc injection of .8, 1.5, and 3.0 mg Cd/kg three times a week for three weeks. Cd levels of liver and kidneys increased with the increment of Cd dosage and 80–90% of Cd was found in the cytosol. The MT fractions contained 80–89% cytosolic Cd in the liver and 55–75% Cd in the kidneys. Zn concentrations in the liver increased following Cd administration, But Zn in the kidneys showed only slight increase. There was a distinct decrease of Cu concentration in the liver of the 3.0 mg group. In contrast, Cu concentrations in the kidneys increased about three times in the .8 and 1.5 mg Cd groups, but Cu in the 3.0 mg group showed only 1.5 times increase. The changes of these metal concentrations were observed mainly in the cytosol. Non-MT-Cd in the kidneys was maximum in the 1.5 mg group, but the 3.0 mg group showed significant decrease. In parallel with this decrease of Cd, Cu and Zn in the kidneys showed similar decrease. When the kidneys are injured, Zn and Cu appear to leak from this organ.     

A Glandular Gift in the German Cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae): The Courtship Feeding of a Female on Secretions from Male Tergal Glands

In the courtship behavior of the German cockroach, the male presents tergal glands to the female and feeds her with glandular secretions to place her in the appropriate precopulatory position. The phagostimulant activity of the secretions was quantitatively examined using the polyethylene glycol film method. The methanol extract of the glands on the eighth tergite induced a potent feeding response in 6-day-old virgin females (EC ₅₀ = 0.0037 male equivalent/40 g PEG spot). However, there was no temporal relation between the feeding response and the sexual receptivity of the females. Moreover, besides virgin females, the extract induced a feeding response in gravid or mated females, males, and the last-instar nymphs. These results strongly suggest that the secretions function as a dietary feeding stimulant in principle but as a courtship pheromone in the context of courtship behavior where the stimulants are offered as a nuptial gift.     

The diversity of mycorrhizal fungi in Japanese Cephalanthera species

The diversity of mycorrhizal fungi among four Japanese Cephalanthera (Orchidaceae) species was examined at a total of seven sites, based on sequence variation in nuclear ribosomal DNA. This is the first report to detect mycorrhizal fungi in C. subaphylla. Two patterns of mycorrhizal associations were confirmed from our results. C. falcata has lower fungal specificity, associating with Russulaceae, Sebacinales and Thelephoraceae. By contrast, the three Cephalanthera species C. erecta, C. subaphylla, and C. longifolia were associated mainly with Thelephoraceae fungi. There is no large difference found in mycobionts between green and albino individuals of C. falcata and no distinct preference of Japanese Cephalanthera species for a specific fungal group of Thelephoraceae.     

Ceiling culture-derived proliferative adipocytes retain high adipogenic potential suitable for use as a vehicle for gene transduction therapy

Adipose tissue is expected to provide a source of proliferative cells for regenerative medicine and cell-transplantation therapies using gene transfer manipulation. We have recently identified ceiling culture-derived proliferative adipocytes (ccdPAs) from the mature adipocyte fraction as cells suitable as a therapeutic gene vehicle because of their stable proliferative capacity. In this study, we examined the capability of adipogenic differentiation of the ccdPAs compared with stromal vascular fraction (SVF)-derived progenitor cells (adipose-derived stem cells, ASCs) with regard to their multipotential ability to be converted to another lineage and therefore their potential to be used for regenerative medicine research. After in vitro passaging, the surface antigen profile and the basal levels of adipogenic marker genes of the ccdPAs were not obviously different from those of the ASCs. However, the ccdPAs showed increased lipid-droplet accumulation accompanied with higher adipogenic marker gene expression after stimulation of differentiation compared with the ASCs. The higher adipogenic potential of the ccdPAs than the ASCs from the SVF was maintained for 42 days in culture. Furthermore, the difference in the adipogenic response was enhanced after partial stimulation without indomethacin. These results indicate that the ccdPAs retain a high adipogenic potential even after in vitro passaging, thus suggesting the commitment of ccdPAs to stable mature adipocytes after autotransplantation, indicating that they may have potential for use in regenerative and gene-manipulated medicine.     

ATP-dependent regulation of inwardly rectifying K+ current in bovine retinal pigment epithelial cells

Inwardlyrectifying K⁺ current(I_Kir) infreshly isolated bovine retinal pigment epithelial (RPE) cells wasstudied in the whole cell recording configuration of the patch-clamptechnique. When cells were dialyzed with pipette solution containing noATP, I_Kir randown completely in <10 min [half time(t_1/2) = 1.9 min]. In contrast, dialysis with 2 mM ATP sustainedI_Kir for 10 min or more. Rundown was also prevented with 4 mM GTP or ADP. When 0.5 mMATP was used,I_Kir ran down by~71%. Mg²⁺ was a criticalcofactor because rundown occurred when the pipette solution contained 4 mM ATP but no Mg²⁺(t_1/2 = 1.8 min).I_Kir also randown when the pipette solution contained 4 mMMg²⁺ + 4 mM5'-adenylylimidodiphosphate(t_1/2 = 2.7 min)or 4 mM adenosine 5'-O-(3-thiotriphosphate)(t_1/2 = 1.9 min),nonhydrolyzable and poorly hydrolyzable ATP analogs, respectively. Weconclude that the sustained activity ofI_Kirin bovine RPE requires intracellular MgATP and that the underlyingmechanism may involve ATP hydrolysis.

     

Photo-induced activation of cytochrome P450/reductase fusion enzyme coupled with spinach chloroplasts

Summary Photoactivation of cytochrome P450 monooxygenase was studied using a combination of spinach chloroplasts and yeast microsomes containing rat P4501A1/yeast reductase fusion enzyme. Under illumination, in the reaction mixture, NADP was reduced, transferring electrons to the P450/reductase fusion enzyme to convert 7-ethoxycoumarin to 7-hydroxycoumarin.     

Nitric oxide inhibits depolarization-evoked glutamate release from rat cerebellar granule cells.

Nitric oxide (NO) modulates the release of various neurotransmitters, some of these are considered to be involved in neuronal plasticity that includes long-term depression in the cerebellum. To date, there have been no reports on the modulation of the exocytotic release of neurotransmitters in the cerebellar granule cells (CGCs) by NO. The aim of this study was to investigate the effects of NO on the exocytotic release of glutamate from rat CGCs. Treatment with NO-related reagents revealed that NO inhibited high-K(+)-evoked glutamate release. Clostridium botulinum type B neurotoxin (BoNT/B) attenuated the enhancement of glutamate release caused by NO synthase (NOS) inhibition; this indicates that NO acts on the high-K(+)-evoked exocytotic pathway. cGMP-related reagents did not affect the high-K(+)-evoked glutamate release. NO-related reagents did not affect Ca(2+) ionophore-induced glutamate release, suggesting that NO inhibits Ca(2+) entry through voltage-dependent Ca(2+) channels (VDCC). Monitoring of intracellular Ca(2+) revealed that NO inhibited high-K(+)-evoked Ca(2+) entry. L-type VDCC blockers inhibited glutamate release and NO did not have an additive effect on the inhibition produced by the L-type VDCC blocker. The inhibition of the high-K(+)-evoked glutamate release by NO was abolished by a reducing reagent; this suggested that NO regulates the high-K(+)-evoked glutamate release from CGCs by redox modulation.