Endogenous neurotoxic dopamine derivative covalently binds to Parkinson's disease‐associated ubiquitin C‐terminal hydrolase L1 and alters its structure and function

Parkinson's disease (PD) is a common neurodegenerative disease, but its pathogenesis remains elusive. A mutation in ubiquitin C‐terminal hydrolase L1 (UCH‐L1) is responsible for a form of genetic PD which strongly resembles the idiopathic PD. We previously showed that 1‐(3′,4′‐dihydroxybenzyl)‐1,2,3,4‐tetrahydroisoquinoline (3′,4′DHBnTIQ) is an endogenous parkinsonism‐inducing dopamine derivative. Here, we investigated the interaction between 3′,4′DHBnTIQ and UCH‐L1 and its possible role in the pathogenesis of idiopathic PD. Our results indicate that 3′,4′DHBnTIQ binds to UCH‐L1 specifically at Cys152 in vitro. In addition, 3′,4′DHBnTIQ treatment increased the amount of UCH‐L1 in the insoluble fraction of SH‐SY5Y cells and inhibited its hydrolase activity to 60%, reducing the level of ubiquitin in the soluble fraction of SH‐SY5Y cells. Catechol‐modified UCH‐L1 as well as insoluble UCH‐L1 were detected in the midbrain of 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine‐treated PD model mice. Structurally as well as functionally altered UCH‐L1 have been detected in the brains of patients with idiopathic PD. We suggest that conjugation of UCH‐L1 by neurotoxic endogenous compounds such as 3′,4′DHBnTIQ might play a key role in onset and progression of idiopathic PD.

     

Serological Surveillance Development for Tropical Infectious Diseases Using Simultaneous Microsphere-Based Multiplex Assays and Finite Mixture Models

Background

A strategy to combat infectious diseases, including neglected tropical diseases (NTDs), will depend on the development of reliable epidemiological surveillance methods. To establish a simple and practical seroprevalence detection system, we developed a microsphere-based multiplex immunoassay system and evaluated utility using samples obtained in Kenya.

Methods

We developed a microsphere-based immuno-assay system to simultaneously measure the individual levels of plasma antibody (IgG) against 8 antigens derived from 6 pathogens: Entamoeba histolytica (C-IgL), Leishmania donovani (KRP42), Toxoplasma gondii (SAG1), Wuchereria bancrofti (SXP1), HIV (gag, gp120 and gp41), and Vibrio cholerae (cholera toxin). The assay system was validated using appropriate control samples. The assay system was applied for 3411 blood samples collected from the general population randomly selected from two health and demographic surveillance system (HDSS) cohorts in the coastal and western regions of Kenya. The immunoassay values distribution for each antigen was mathematically defined by a finite mixture model, and cut-off values were optimized.

Findings

Sensitivities and specificities for each antigen ranged between 71 and 100%. Seroprevalences for each pathogen from the Kwale and Mbita HDSS sites (respectively) were as follows: HIV, 3.0% and 20.1%; L. donovani, 12.6% and 17.3%; E. histolytica, 12.8% and 16.6%; and T. gondii, 30.9% and 28.2%. Seroprevalences of W. bancrofti and V. cholerae showed relatively high figures, especially among children. The results might be affected by immunological cross reactions between W. bancrofti-SXP1 and other parasitic infections; and cholera toxin and the enterotoxigenic E. coli (ETEC), respectively.

Interpretation

A microsphere-based multi-serological assay system can provide an opportunity to comprehensively grasp epidemiological features for NTDs. By adding pathogens and antigens of interest, optimized made-to-order high-quality programs can be established to utilize limited resources to effectively control NTDs in Africa.     

Evidence for detection of rat P2X4 receptor expressed on cells by generating monoclonal antibodies recognizing the native structure

Purinergic Signalling - P2X purinergic receptors are ATP-driven ionic channels expressed as trimers and showing various functions. A subtype, the P2X4 receptor present on microglial cells is highly...     

Direct and feeding‐induced interactions between two rice planthoppers, Sogatella furcifera and Nilaparvata lugens: effects on dispersal capability and performance

Abstract. 1. A series of laboratory experiments was conducted to explore the effects of inter‐specific interactions, both direct interactive effects and those induced through previous feeding, on the dispersal capability (proportion of macropterous adults) and performance (development time and survival) of two wing‐dimorphic planthoppers, the whitebacked planthopper Sogatella furcifera and the brown planthopper Nilaparvata lugens, two pests of rice throughout Asia. 2. An asymmetric effect of inter‐specific crowding on dispersal capability was detected between the two planthoppers. With density controlled, the proportion of macropterous adults in N. lugens was higher when raised in mixed populations with S. furcifera than in pure cultures comprised of conspecifics, suggesting that interspecific effects on dispersal capability are stronger than intraspecific effects. In contrast, interspecific effects on macroptery (%) were weaker than intraspecific impacts for S. furcifera. 3. This trend was parallelled by adverse competitive effects on survival, with interspecific effects stronger than intraspecific impacts for N. lugens and intraspecific effects stronger for S. furcifera. 4. Crowding also affected the incidence of macroptery indirectly through feeding‐induced changes in plant physiology. Rearing N. lugens on plants fed on previously by heterospecifics resulted in a higher incidence of macroptery in females and protracted development than for N. lugens raised on plants fed on previously by conspecifics. By contrast, the intraspecific effect of previous feeding was stronger than the interspecific effect in S. furcifera, with higher macropter production and prolonged development occurring on plants exposed previously to conspecifics. 5. The results suggest that interspecific interactions between herbivorous insects, both direct and via feeding‐induced changes in plant physiology, can have negative consequences for performance and survival and promote the production of flight‐capable adults that can disperse.     

Brain-derived Neurotrophic Factor (BDNF) Induces Sustained Intracellular Ca2+ Elevation through the Up-regulation of Surface Transient Receptor Potential 3 (TRPC3) Channels in Rodent Microglia

Microglia are immune cells that release factors, including proinflammatory cytokines, nitric oxide (NO), and neurotrophins, following activation after disturbance in the brain. Elevation of intracellular Ca²⁺ concentration ([Ca²⁺]_i) is important for microglial functions such as the release of cytokines and NO from activated microglia. There is increasing evidence suggesting that pathophysiology of neuropsychiatric disorders is related to the inflammatory responses mediated by microglia. Brain-derived neurotrophic factor (BDNF) is a neurotrophin well known for its roles in the activation of microglia as well as in pathophysiology and/or treatment of neuropsychiatric disorders. In this study, we sought to examine the underlying mechanism of BDNF-induced sustained increase in [Ca²⁺]_i in rodent microglial cells. We observed that canonical transient receptor potential 3 (TRPC3) channels contribute to the maintenance of BDNF-induced sustained intracellular Ca²⁺ elevation. Immunocytochemical technique and flow cytometry also revealed that BDNF rapidly up-regulated the surface expression of TRPC3 channels in rodent microglial cells. In addition, pretreatment with BDNF suppressed the production of NO induced by tumor necrosis factor α (TNFα), which was prevented by co-adiministration of a selective TRPC3 inhibitor. These suggest that BDNF induces sustained intracellular Ca²⁺ elevation through the up-regulation of surface TRPC3 channels and TRPC3 channels could be important for the BDNF-induced suppression of the NO production in activated microglia. We show that TRPC3 channels could also play important roles in microglial functions, which might be important for the regulation of inflammatory responses and may also be involved in the pathophysiology and/or the treatment of neuropsychiatric disorders.     

Formation of Chlorophyll-Protein Complexes during Greening 1. Distribution of Newly Synthesized Chlorophyll among Apoproteins

The relationship between the accumulation of Chl and the apoproteinsof the light-harvesting Chl a/b-protein complex of PS II (LHCII)during the greening of cucumber cotyledons was studied. LHCIIapoproteins were not detected in etiolated cotyledons. Uponillumination, Chl a was formed as a result of photoconversionof protochlorophyllide (Pchlide) which had accumulated in thedark. During the lag period that preceded the accumulation ofChl, a small amount of LHCII apoproteins appeared. The amountof LHCII apoproteins increased with increases in levels of Chlb, though somewhat more rapidly during the first 10 h of greening.Treatment with benzyladenine (BA) or levulinic acid (LA) wasused to vary the supply of Chl a for apoproteins by promotingor inhibiting the synthesis of Chl a, respectively. LA decreasedbut BA increased the rate of accumulation of Chl b and LHCIIapoproteins. Only small amounts of Chl b and LHCII apoproteinswere formed under intermittent illumination. However, in thepresence of chloramphenicol (CAP), which inhibits the synthesisof plastome-coded proteins including apoproteins of the P700-Chla-protein complex (CP1) and a Chl a-protein complex of PS II(CPa), we observed the accumulation of Chl b and LHCII apoproteins,both of which are of nuclear origin. During incubation in thedark after intermittent exposure to light, CAP alone allowedneither destruction nor accumulation of Chl b and LHCII apoproteins,but it did enhance the effect of CaCl₂ in inducing both Chlb and these apoproteins. These results can be explained by assumingthat apoproteins of CP1 and CPa have a higher affinity for Chla than do LHCII apoproteins. When the availability of Chl ais limited, these apoproteins compete with one another for Chla, with the resultant preferential formation of CP1 and CPa.However, when the supply of Chl a becomes large enough for saturationof apoproteins of CP1 and CPa, some of the Chl a is incorporatedinto LHCII apoproteins either directly or after conversion toChl b. Thus, the formation of different Chl-protein complexes(CPs) is regulated by the relative rates of synthesis of Chla and apoproteins and by differential affinities of the apoproteinsfor Chl a. ⁴Present address: Kyowa Hakko Co., Ltd., 4041, Ami-machi, Inashiki,Ibaraki, 300-03 Japan (Received September 14, 1989; Accepted April 26, 1990)     

Russula velenovskyi new to Japan,with phylogenetic implications of Russula species between Japanese subalpine forests and Northern Europe

To compare morphological characters and phylogenetic placement between Japanese and European Russula, 32 specimens of 12 species were collected from Japanese subalpine forests and Northern Europe. Several sequences of nrDNA ITS region (ITS) of these Russula species were obtained. High homological similarities were shown between ITS sequences of several Russula samples collected from Japanese subalpine forests, Europe and North America. These facts show distribution of the same Russula species among these areas. From morphological observations and phylogenetic analyses, two same Russula species, R. velenovskyi, and R. decolorans are found in Japan, Europe and North America. Of these, R. velenovskyi collected from Mt. Fuji, Mt. Nyukasa and Mt. Tateshina in mountainous area of central Honshu is reported as a new Japanese record.     

Effects of dibutyryl cAMP and bromodeoxyuridine on expression ofN-acetylglucosaminyltransferases III and V in GOTO neuroblastoma cells

The sugar chain structures of the cell surface change dramatically during cellular differentiation. A human neuroblastoma cell line, GOTO, is known to differentiate into neuronal cells and Schwannian cell-like cells on treatments with dibutyryl cAMP and bromodeoxyuridine, respectively. We have examined the expression of UDP-N-acetylglucosamine: -d-mannoside -1,4N-acetylglucosaminyltransferase III (GnT-III: EC 2.4.1.144) and UDP-N-acetylglucosamine: -6-d-mannoside -1,6N-acetylglucosaminyltransferase V (GnT-V: EC 2.4.1.155), two major branch forming enzymes inN-glycan synthesis, in GOTO cells on two distinct directions of differentiation.In neuronal cell differentiation, GnT-III activity showed a slight increase during initial treatment with Bt₂cAMP for 4 days and decreased drastically after the fourth day, but the mRNA level of GnT-III did not show a decrease but in fact a slight increase. GnT-V activity increased to approximately two- to three-fold the initial level with increasing mRNA level after 8 days, and lectin blot analysis showed an increase in reactivity toDatsura stramonium (DSA) of the immunoprecipitated neural cell adhesion molecule (NCAM). In Schwannian cell differentiation, the activity and mRNA level of GnT-III showed no significant change on treatment with BrdU. GnT-V activity also showed no change in spite of the gradual increase in the mRNA level. These results suggest that the activation of GnT-V during neuronal cell differentiation of GOTO cells might be a specific change for branch formation in N-glycans, and this affects the sugar chain structures of some glycoproteins such as NCAM.Abbreviations and trivial names GnT N-acetylglucosaminyltransferase - Bt₂cAMP N ⁶,O ⁶-dibutyryl cAMP - BrdU bromodeoxyuridine - DSA Datsura stramonium - NCAM neural cell adhesion molecule - PAGE polyacrylamide gel electrophoresis