Hordeum vulgare CYP76M57 catalyzes C2 shortening of tryptophan side chain by C-N bond rearrangement in gramine biosynthesis

The indole alkaloid gramine, 3-(dimethylaminomethyl)indole, is a defensive specialized metabolite found in some barley cultivars. In its biosynthetic process, the tryptophan (Trp) side chain is shortened by two carbon atoms to produce 3-(aminomethyl)indole (AMI), which is then methylated by N-methyltransferase (HvNMT) to produce gramine. Although side chain shortening is one of the crucial scaffold formation steps of alkaloids originating from aromatic amino acids, the gene and enzyme involved in the Trp-AMI conversion reactions are unknown. In this study, through RNA-seq analysis, 35 transcripts were shown to correlate with gramine production; among them, an uncharacterized cytochrome P450 (CYP) gene, CYP76M57, and HvNMT were identified as candidate genes for gramine production. Transgenic Arabidopsis thaliana and rice overexpressing CYP and HvNMT accumulate AMI, N-methyl-AMI, and gramine. CYP76M57, heterologously expressed in Pichia pastoris, was able to act on Trp to produce AMI. Furthermore, the amino group nitrogen of Trp was retained during the CYP76M57-catalyzed reaction, indicating that the C2 shortening of Trp proceeds with an unprecedented biosynthetic process, the removal of the carboxyl group and Cα and the rearrangement of the nitrogen atom to Cβ. In some gramine-non-accumulating barley cultivars, arginine 104 in CYP76M57 is replaced by threonine, which abolished the catalytic activity of CYP76M57 to convert Trp into AMI. These results uncovered the missing committed enzyme of gramine biosynthesis in barley and contribute to the elucidation of the potential functions of CYPs in plants and undiscovered specialized pathways.

Impact of the COVID-19 pandemic on the incidence of surgical site infection after orthopaedic surgery: an interrupted time series analysis of the nationwide surveillance database in Japan

BACKGROUND

During the COVID-19 pandemic, hygiene awareness was increased in communities and hospitals. However, there is controversy regarding whether such circumstances affected the incidence of surgical site infections (SSIs) in the orthopaedic surgical field.

AIM

To examine the impact of the COVID-19 pandemic on the incidence of SSIs after orthopaedic surgery.

METHODS

The medical records of patients having undergone orthopaedic surgery were extracted from the nationwide surveillance database in Japan. The primary outcomes were the monthly incidences of total SSIs, deep or organ/space SSIs, and SSIs due to meticillin-resistant Staphylococcus aureus (MRSA). Interrupted time series analysis was conducted between pre-pandemic (January 2017 to March 2020) and pandemic (April 2020 to June 2021) periods.

RESULTS

A total of 309,341 operations were included. Interrupted time series analysis adjusted for seasonality showed no significant changes in the incidence of total SSIs (rate ratio 0.94 and 95% confidence interval 0.98-1.02), deep or organ/space SSIs (0.91, 0.72-1.15), or SSIs due to MRSA (1.07, 0.68-1.68) along with no remarkable slope changes in any parameter (1.00, 0.98-1.02; 1.00, 0.97-1.02; and 0.98, 0.93-1.03, respectively).

CONCLUSIONS

Awareness and measures against the COVID-19 pandemic did not markedly influence the incidence of total SSIs, deep or organ/space SSIs, or SSIs due to MRSA following orthopaedic surgery in Japan.

Detection of a novel intramolecular rearrangement during gramine biosynthesis in barley using stable isotope-labeled tryptophan

Plants accumulate various secondary metabolites, and the biosynthetic reactions responsible for their scaffold construction are the key steps that characterize their structural categories. Gramine, an indole alkaloid, is a defensive secondary metabolite biosynthesized in barley (Hordeum vulgare) from tryptophan (Trp) via aminomethylindole (AMI). While the two sequential N-methylation steps following the formation of AMI have already been characterized both genetically and enzymatically, the step preceding AMI formation, which includes the Trp side chain-shortening, has not yet been revealed. To gain further insight into these biosynthetic reactions, barley seedlings were fed Trp labeled with stable isotopes (¹³C and ¹⁵N) at various positions, and the isotope incorporation into gramine was analyzed by liquid chromatography/mass spectrometry. Significant increases in the abundance of isotopic gramine were detected in experimental sets in which Trp was labeled at either the indole ring, the β-carbon, or the amino group, whereas the isotopolog composition was not affected by α-carbon-labeled Trp. Although absorbed Trp presumably undergoes transamination in plants, this reaction did not seem to be related to gramine productivity. The data indicated that AMI directly inherited the amino group from Trp, while the α-carbon was removed, suggesting that the Trp-AMI conversion includes a novel intramolecular rearrangement reaction. The results of this study provide novel insights into scaffold formation in plant secondary-metabolite synthesis.

Nanosecond Random Telegraph Noise in In-Plane Magnetic Tunnel Junctions

We study the timescale of random telegraph noise (RTN) of nanomagnets in stochastic magnetic tunnel junctions (MTJs). From analytical and numerical calculations based on the Landau-Lifshitz-Gilbert and the Fokker-Planck equations, we reveal mechanisms governing the relaxation time of perpendicular easy-axis MTJs (p-MTJs) and in-plane easy-axis MTJs (i-MTJs), showing that i-MTJs can be made to have faster RTN. Superparamagnetic i-MTJs with small in-plane anisotropy and sizable perpendicular effective anisotropy show relaxation times down to 8 ns at negligible bias current, which is more than 5 orders of magnitude shorter than that of typical stochastic p-MTJs and about 100 times faster than the shortest time of i-MTJs reported so far. The findings give a new insight and foundation in developing stochastic MTJs for high-performance probabilistic computers.

Identification of novel BCL11A variants in patients with epileptic encephalopathy: Expanding the phenotypic spectrum

BCL11A encodes a zinc finger protein that is highly expressed in hematopoietic tissues and the brain, and that is known to function as a transcriptional repressor of fetal hemoglobin (HbF). Recently, de novo variants in BCL11A have been reported in individuals with intellectual disability syndrome without epilepsy. In this study, we performed whole-exome sequencing of 302 patients with epileptic encephalopathies (EEs), and identified 2 novel BCL11A variants, c.577delC (p.His193Metfs*3) and c.2351A>C (p.Lys784Thr). Both the patients shared major physical features characteristic of BCL11A-related intellectual disability syndrome, suggesting that characteristic physical features and the persistence of HbF should lead clinicians to suspect EEs caused by BCL11A pathogenic variants. Patient 1, with a frameshift variant, presented with Lennox-Gastaut syndrome, which expands the phenotypic spectrum of BCL11A haploinsufficiency. Patient 2, with a p.Lys784Thr variant, presented with West syndrome followed by drug-resistant focal seizures and more severe developmental disability. These 2 newly described patients contribute to delineating the associated, yet uncertain phenotypic characteristics of BCL11A disease-causing variants.

Comparative proteomic profiling reveals aberrant cell proliferation in the brain of embryonic Ts1Cje, a mouse model of Down syndrome

To identify molecular candidates involved in brain disabilities of Ts1Cje, a mouse model of Down syndrome (DS), we performed comparative proteomic analyses. Proteins extracted from the brains of postnatal wild-type (WT) and Ts1Cje mice were analyzed by two-dimensional gel electrophoresis (2-DE). No differences were detected in the proteins expressed in the whole brain between WT and Ts1Cje mice at postnatal day 0 and 3months of age. Five spots with differential expression in the brains of Ts1Cje mice were detected by 2-DE of brain proteins from WT and Ts1Cje embryos at embryonic day 14.5 (E14.5). These differentially expressed proteins in Ts1Cje embryos were identified as calcyclin-binding protein (CACYBP), nucleoside diphosphate kinase-B (NDPK-B), transketolase (TK), pyruvate kinase (PK), and 60S acidic ribosomal protein P0 (RPLP0) by peptide mass fingerprinting. CACYBP and NDPK-B were involved in cell proliferation, whereas TK and PK were associated with energy metabolism. Experiments on cell proliferation, an in vivo bromodeoxyuridine (BrdU)-labeling experiment, and immunohistochemical analysis for phospho-histone H3 (an M-phase marker) demonstrated increased numbers of BrdU-positive and M-phase cells in the ganglionic eminence. Our findings suggest that the dysregulated expression of proteins demonstrated by comparative proteomic analysis could be a factor in increased cell proliferation, which may be associated with abnormalities in DS brain during embryonic life.

A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction

Magnetic tunnel junctions (MTJs) with ferromagnetic electrodes possessing a perpendicular magnetic easy axis are of great interest as they have a potential for realizing next-generation high-density non-volatile memory and logic chips with high thermal stability and low critical current for current-induced magnetization switching. To attain perpendicular anisotropy, a number of material systems have been explored as electrodes, which include rare-earth/transition-metal alloys, L1(0)-ordered (Co, Fe)-Pt alloys and Co/(Pd, Pt) multilayers. However, none of them so far satisfy high thermal stability at reduced dimension, low-current current-induced magnetization switching and high tunnel magnetoresistance ratio all at the same time. Here, we use interfacial perpendicular anisotropy between the ferromagnetic electrodes and the tunnel barrier of the MTJ by employing the material combination of CoFeB-MgO, a system widely adopted to produce a giant tunnel magnetoresistance ratio in MTJs with in-plane anisotropy. This approach requires no material other than those used in conventional in-plane-anisotropy MTJs. The perpendicular MTJs consisting of Ta/CoFeB/MgO/CoFeB/Ta show a high tunnel magnetoresistance ratio, over 120%, high thermal stability at dimension as low as 40 nm diameter and a low switching current of 49 microA.

Structural significance of N-glycans of the zona pellucida on species-selective recognition of spermatozoa between pig and cattle

The zona pellucida that surrounds the mammalian oocyte plays a role in species-selective sperm-egg interactions. In the pig and cattle, the zona pellucida consists of ZPA, ZPB and ZPC. Sperm binding activity of porcine zona glycoproteins is conferred by tri- and tetra-antennary complex-type in cattle it is conferred by a high-mannose-type chain o f f ive mannose residues. Non-reducing terminal residues of these N-linked chains, beta-galactosyl residues in pig and alpha-mannosyl residues in cattle, are involved in the binding of zona glycoproteins to respective spermatozoa. The major N-linked chains of recombinant porcine ZPB expressed using the baculovirus-Sf9 cell expression system are pauci- and high-mannose-type chains that are different in structure to the major neutral N-linked chains of the porcine zona but similar to those of the bovine zona. The mixture of porcine ZPB/ZPC co-expressed in Sf9 cells binds to bovine sperm but not to porcine sperm, indicating an essential role of the N-linked chains in species-selective recognition of sperm in pig and cattle. Asn to Asp mutations at either of two of the N-glycosylation sites of ZPB, residue 203 or 220, significantly reduce the sperm-binding activity of the ZPB/ZPC mixture, while a similar mutation at Asn333 has no effect on binding. These results coincide with our previous report that tri- and tetra-antennary complex-type chains are localized at Asn220 in native porcine ZPB and suggest that the N-glycans located in the N-terminal half of the ZP domain of porcine ZPB are involved in sperm-zona binding.

Depression of sink activity precedes the inhibition of biomass production in tomato plants subjected to potassium deficiency stress

Tomato [Solanum lycopersicum (formerly Lycopersicon esculentum) L. cv. Momotarou] plants were grown hydroponically inside the greenhouse of Hiroshima University, Japan. The adverse effects of potassium (K) deficiency stress on the source-sink relationship during the early reproductive period was examined by withdrawing K from the rooting medium for a period of 21 d. Fruits and stem were the major sink organs for the carbon assimilates from the source. A simple non-destructive micro-morphometric technique was used to measure growth of these organs. The effect of K deficiency was studied on the apparent photosynthesis (source activity), leaf area, partitioning (13)C, sugar concentration, K content, and fruit and stem diameters of the plant. Compared with the control, K deficiency treatment severely decreased biomass of all organs. The treatment also depressed leaf photosynthesis and transport of (13)C assimilates, but the impact of stress on these activities became evident only after fruit and stem diameter expansions were down-regulated. These results suggested that K deficiency diminished sink activity in tomato plants prior to its effect on the source activity because of a direct effect on the water status of the former. The lack of demand in growth led to the accumulation of sugars in leaves and concomitant fall in photosynthetic activity. Since accumulation of K and sugars in the fruit was not affected, low K levels of the growing medium might not have affected the fruit quality. The micro-morphometric technique can be used as a reliable tool for monitoring K deficiency during fruiting of tomato. K deficiency directly hindered assimilate partitioning, and the symptoms were considered more detrimental compared with P deficiency.

Dose-dependency of Life Span Prolongation of F344/DuCrj Rats Injected with (−)deprenyl

The effect of (-)deprenyl (D) on prolonging survival has previously been reported in different species of animals. In rats, three studies reported a positive effect, while one study reported a shortening of life spans. In the present study, we attempted to clarify past discrepancies in the results based on the speculation that there exists a certain effective dose range for this effect of the drug. F344/DuCrj rats of both sexes began to receive subcutaneous (s.c.) injections of D at the age of 18 months at a dose of 0.25 mg/kg/injection (inj.), 3 times a week. Control animals were given a vehicle (a saline solution). Average life spans of animals (days) were significantly increased in both male (895 +/- 109.7, n=30; 967.8 +/- 88.6, n=30, control vs. D treated, P<0.01, t-test) and female (924.7 +/- 132.2, n=38; 987.1 +/- 133.4, n=39, P<0.05) rats by 8.1% and 6.7%, respectively. We have previously reported that a dose of 0.5mg/kg/inj. (s.c.) significantly increased the life span of male F344 rats, while a dose of 1.0 mg/kg/inj. somewhat shortened the life span, although the difference was not statistically significant. The results of the present study coupled with our previous reports clearly indicate that a proper dose of D within a certain dose range can significantly increase the life span of animals of both sexes, but that a greater dose becomes less effective and may actually adversely affect the life span of rats. The presence of this effective dose range of D may explain discrepancies in the effect of D on life spans of animals previously reported.

Participation of the nonreducing terminal beta-galactosyl residues of the neutral N-linked carbohydrate chains of porcine zona pellucida glycoproteins in sperm-egg binding

The zona pellucida (ZP) surrounding the mammalian oocyte is composed of three glycoprotein components (ZPA, ZPB, and ZPC). Mammalian sperm bind to carbohydrate chains of a ZP glycoprotein in the initial phase of fertilization. Sperm-ligand carbohydrate chains have been characterized in mouse, cow, and pig. In pigs, triantennary/tetraantennary neutral complex-type chains from ZPB/ZPC mixture possess stronger sperm-binding activity than those of biantennary chains (Kudo et al., 1998: Eur J Biochem 252:492-499). Most of these oligosaccharides have beta-galactosyl residues at the nonreducing ends. This study used two in vitro competition assays to investigate the participation of the nonreducing terminal beta-galactosyl residues of the ligand active chains in porcine sperm binding. The removal of the nonreducing terminal beta-galactosyl residues from either the ligand active carbohydrate chains or endo-beta-galactosidase-digested glycoproteins significantly reduced their inhibition of sperm-egg binding, indicating that the beta-galactosyl residues at the nonreducing ends are involved in porcine sperm-egg binding. A correlation between the sperm-binding activity and in vitro fertilization rate is also presented.

Characterization of Oita virus 296/1972 of Rhabdoviridae isolated from a horseshoe bat bearing characteristics of both lyssavirus and vesiculovirus

Oita virus 296/1972 was isolated from the blood of a wild horseshoe bat, Rhinolophus cornutus (Temminck) in 1972. We investigated the pathogenicity of this virus in mice in relation to its histological, immunohistochemical and ultrastructural characteristics and the entire sequence of nucleoprotein gene. This virus caused lethal encephalitis in mice through intracerebral route. This susceptibility of mice was until 3 weeks of age. Immunohistochemical analysis using the convalescent sera obtained from survived adult mice after intracerebral inoculation revealed that many neurons were positive in the cytoplasm, besides no cross reactivity with normal and rabies virus-infected mouse brain tissues to this anti-sera. Ultrastructural analysis disclosed many bullet-shaped and enveloped virions in neurons. These morphological characteristics of the virions are consistent of that of viruses in the family Rhabdoviridae. Budding from endoplasmic membrane suggests that this virus has a similarity with lyssaviruses. Molecular analysis of cDNA coding a tentative nucleoprotein sequence revealed homology with those of viruses in the family Rhabdoviridae. Distance matrix analysis of this gene sequence with those of other rhabdoviruses isolated from mammals disclosed the discrete position of this virus in the phylogenic tree of rhabdoviridae infecting mammals and we renamed this virus as Oita rhabdovirus.

Inhibitory effect of somatostatin on cholecystokinin release is independent of luminal cholecystokinin-releasing factor content in conscious rats

INTRODUCTION

Exclusion of bile-pancreatic juice from the intestine increases pancreatic secretion via cholecystokinin (CCK) release in conscious rats. Luminal CCK-releasing factor (LCRF), purified from rat intestinal secretions, is an intraluminal regulator of CCK secretion during bile-pancreatic juice diversion.

AIMS

Because somatostatin is a potent inhibitor of CCK release and pancreatic secretion, the inhibitory effect of somatostatin on LCRF was examined.

METHODOLOGY

Rats were prepared with bile and pancreatic cannulae and two duodenal cannulae and with an external jugular vein cannula. The experiments were conducted without anesthesia. After 1.5-hour basal collection of pancreatic juice with bile-pancreatic juice return, bile-pancreatic juice was diverted for 2 hours, during which time somatostatin (2, 10 nmol/kg/h) was infused intravenously. The rats were killed before and 1 and 2 hours after bile-pancreatic juice diversion. To examine the effect of luminal somatostatin, 50 or 200 nmol/kg/h of somatostatin was infused into the duodenum. The plasma CCK and luminal content of LCRF were measured by specific radioimmunoassays.

RESULTS

Bile-pancreatic juice diversion significantly increased pancreatic secretion, plasma CCK, and LCRF levels. Intravenous infusion of somatostatin inhibited CCK release and pancreatic secretion, but not LCRF content. Luminal administration of somatostatin did not show any effect.

CONCLUSION

Inhibitory effect of circulating somatostatin on CCK release and pancreatic secretion is independent of LCRF content.

Early full donor myeloid chimerism after reduced-intensity stem cell transplantation using a combination of fludarabine and busulfan

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate lineage-specific chimerism reconstitution after reduced-intensity allogeneic stem cell transplantation (RIST) using a combination of fludarabine (30 mg/m2 for 6 days) and busulfan (4 mg/kg for 2 days).

DESIGN AND METHODS

We prospectively enrolled 8 consecutive patients with hematologic malignancies who were not candidates for conventional transplantation because of either high age or organ dysfunction. Host-donor chimerism was evaluated using polymerase chain reaction-based amplification of a polymorphic short tandem repeat region.

RESULTS

All of our patients achieved engraftment within a median of 11 days after transplantation. On day 30, full donor myeloid cell chimerism (>90%) was achieved in 7 patients whereas full donor T-cell chimerism was achieved in only one patient. Thus, in contrast to other reported results, full donor chimerism was achieved earlier in the myeloid lineage than the T-cell lineage. On day 60, however, T-cell chimerism caught up with myeloid chimerism. Two patients developed grade II-IV acute graft-versus-host disease (GVHD) before the detection of full donor T-cell chimerism.

INTERPRETATION AND CONCLUSIONS

Our findings suggest that the kinetics of lineage-specific chimerism depend on the agents used in the conditioning regimen, and may provide insight into the chimerism kinetics and pathogenesis of GVHD. Thus, the strategy for controlling immunosuppression after RIST should be modified according to the type of conditioning regimen applied.

Importance of CCK-A receptor for gallbladder contraction and pancreatic secretion: a study in CCK-A receptor knockout mice

Bile and pancreatic secretions were determined in a CCK-A receptor deficient mouse mutant generated by gene targeting in embryonic stem cells. The targeting vector contained lacZ and neo insertions in exon 2. Under the urethane anesthesia, the common bile duct was cannulated, and the mixture of bile-pancreatic juice was collected every 30 min. After the 1 h basal secretion, CCK-8 (0.5 and 1.0 nmol/kg), acetylcholine (500 nmol/kg), and neuromedin C (1.0 micromol/kg) were injected subcutaneously, and the secretions were collected following 1 h. Amylase and bile acid outputs were determined as parameters of pancreatic secretion and gallbladder contraction, respectively. In some CCK-A receptor (+/-) animals, LacZ staining was performed. CCK-8 significantly increased amylase and bile acid outputs in CCK-A receptor (+/+) and (+/-) mice, whereas no response was observed in (-/-) mice. Neuromedin C and acetylcholine increased amylase secretion in CCK-A receptor (-/-) mice similar to (+/-) and (+/+) mice. The same doses of neuromedin C and acetylcholine could not increase bile acid secretion. The gallbladder smooth muscles, pancreatic acinar cells, duct cells, and islets were stained by LacZ. CCK and CCK-A receptor are important for pancreatic secretion and gallbladder contraction. Neuromedin C and acetylcholine may compensate pancreatic function, but not gallbladder contraction.

Induction of tumor specific cytotoxic T lymphocytes in prostate cancer using prostatic acid phosphatase derived HLA-A2402 binding peptide

PURPOSE

Human prostatic acid phosphatase is a prostate specific differentiation antigen. Prostatic acid phosphatase levels increase in the serum of patients with prostate cancer and its peptide from positions 299 to 307 (PAP 299-307) is recognized by HLA-A2 restricted cytotoxic T lymphocytes. We investigated whether HLA-A2402 binding prostatic acid phosphatase derived peptides induce HLA-A2402 restricted, tumor specific cytotoxic T lymphocytes from the peripheral blood mononuclear cells of patients with prostate cancer.

MATERIALS AND METHODS

Peptide binding activity was measured with RMA-S-A*A2402 cell lines and flow cytometry. Cytotoxic T-lymphocyte activity of the peripheral blood mononuclear cells of patients with prostate cancer and healthy donors was measured by interferon-gamma and (51)creatinine release assays. Prostatic acid phosphatase expression in the tumor cell lines at the messenger RNA and protein levels was investigated by reverse transcriptase-polymerase chain reaction and immunohistochemical analysis, respectively.

RESULTS

An HLA-A2402 binding, prostatic acid phosphatase derived peptide consisting of the prostatic acid phosphatase amino acid sequence from positions 213 to 221 (PAP 213-221, LYCESVHNF) showed the ability to induce HLA-A2402 restricted and tumor specific cytotoxic T lymphocytes, which are cytoxic to prostatic acid phosphatase positive tumor cells from the peripheral blood mononuclear cells of patients with prostate cancer.

CONCLUSIONS

PAP 213-221 may be appropriate as a cancer vaccine for specific immunotherapy in patients with HLA-A2402 positive prostate cancer.

Synthesis of lipid A type pyran carboxylic acids with ether chains and their biological activities

Synthesis of lipid A type pyran carboxylic acids having ether chains at both the C-3' and C-4 positions and their bioactivities toward human U937 cells are described.

Successful application of nonmyeloablative transplantation for paroxysmal nocturnal hemoglobinuria

OBJECTIVE

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematopoietic stem cell disorder that manifests as hemolytic anemia, venous thrombosis, and deficient hematopoiesis. Although allogeneic hematopoietic stem cell transplantation is considered the only curative therapeutic measure, transplant-related mortality is not negligible. Several studies supported the use of nonmyeloablative stem cell transplantation (NST) for patients of advanced age or with organ dysfunction. Hence, we used NST in a PNH patient who suffered from acute renal failure due to repeated episodes of hemolysis.

MATERIALS AND METHODS

We performed NST using a conditioning regimen consisting of cladribine 0.11 mg/kg x 6, busulfan 4 mg/kg x 2, and rabbit anti-thymocyte globulin 2.5 mg/kg x 2. He received peripheral blood stem cells from his human leukocyte antigen-matched brother. Prophylaxis against graft-vs-host disease was performed with cyclosporine A alone. Chimerism of peripheral blood mononuclear cells was evaluated serially using short tandem repeat analysis and flow cytometry.

RESULTS

No meaningful regimen-related toxicities were documented. Donor chimerism of 90 to 100% was achieved on day 14 and thereafter. The patient is doing well, without any recurrence of hemolysis 6 months after transplant. Follow-up chimerism studies confirmed stable and functioning donor-type hematopoiesis.

CONCLUSIONS

NST may become a safe and curative approach in patients with PNH. Further studies are needed to establish the role of NST for treatment of PNH.

Synthesis of GLA-60 type pyran carboxylic acids with an alkyl chain instead of an ester chain as LPS-antagonists

Synthesis of GLA-60 type pyran carboxylic acid analogues with an alkyl chain instead of an ester chain and their LPS-antagonist activity toward human U937 cells are described.

Common properties for propargylamines of enhancing superoxide dismutase and catalase activities in the dopaminergic system in the rat: implications for the life prolonging effect of (-)deprenyl

(-)Deprenyl has been reported to prolong the life span of different animal species. Further, the drug effectively increases antioxidant enzyme activities such as superoxide dismutase (SOD) and catalase (CAT) in brain dopaminergic regions. We have found that the effect of the drug on antioxidant enzyme activities is highly dose dependent, increasing with an increasing dose, however, a higher dose becomes less effective and an excessive dose becomes adversely effective. Most importantly, an optimal dose for the effect varies widely depending on animal species, strain, sex, age and duration of the treatment, which may at least partly explain discrepancies reported among different studies in the past. From the parallelism of the dose-effect relationship of the drug between life span extension and increasing endogenous antioxidant enzyme activity, we have suggested that the above two effects of (-)deprenyl may be causally related. This review summarizes our past series of studies and also reports our very recent observation that other propargylamines such as rasagiline and (R)-N-(2-heptyl)-N-methylpropagylamine (R-2HMP) also share the property of enhancing antioxidant enzyme activities. Further, our most recent study has found that these propargylamines increase antioxidant enzyme activities not only in brain dopaminergic regions but in extra-brain dopaminergic tissues such as the heart and kidneys. These observations are discussed in relation to the life prolonging effect of (-)deprenyl reported in the past.

Do antioxidant strategies work against aging and age-associated disorders? Propargylamines: a possible antioxidant strategy

The free radical theory of aging was initially proposed by Harman half a century ago primarily to explain biological aging processes. Although administration of so-called antioxidant chemicals, which have been tested in the past for several decades, turned out to be mostly ineffective in prolonging the life spans of animals, the same theory of age-associated diseases appears to be increasingly supported in the last two decades. Despite these difficulties, the success in extending life span of 4 different animal species (mice, rats, hamsters, and dogs) with (-)deprenyl (including a study of our group) indicates that there might exist another type of antioxidant strategy in addition to a simple administration of antioxidant chemicals. (-)Deprenyl has also been shown to increase superoxide dismutase (SOD) and catalase (CAT) activities selectively in brain dopaminergic tissues. Interestingly, we have recently shown that another propargylamine, rasagiline not only increases antioxidant enzyme activities (CAT and SOD) in brain dopaminergic regions as (-)deprenyl does, but also increases CAT and SOD activities in extrabrain catecholaminergic systems such as the heart and kidneys as well. These recent observations coupled with previous observations on the life span of animals with (-)deprenyl suggest that pharmacological modulation of endogenous antioxidant enzyme activities could be one potential antioxidant strategy against aging and age-associated disorders. If the causal relationship between the two effects of (-)deprenyl exists as we hypothesized, we might be able to advance the elucidation of mechanism(s) of aging based on the free radical theory of aging.

A high dose of long term treatment with deprenyl loses its effect on antioxidant enzyme activities as well as on survivals of Fischer-344 rats

The survival rate of male Fischer-344/Du rats treated chronically with high doses of deprenyl was investigated. Eighteen month old rats were treated with 1 mg/kg s.c. deprenyl 3 times per week for 13 months. At the age of 31 months, treated rats showed a greater mortality rate with three of 12 rats surviving, while in saline-treated control animals seven of 12 animals survived. No significant differences in superoxide dismutase (SOD) or catalase (CAT) activities in brain regions of control and treated animals were seen at 31 months of age. In contrast, when 27 month old rats were treated in the same manner for one month, significant increases in SOD (both Cu,Zn- and Mn-) and CAT activities were found in substantia nigra, striatum and cerebral cortex, but not in hippocampus. This effect was produced with a wide range of deprenyl doses (0.25-2 mg/kg, but not 4 mg/kg). Although a causal relationship between the two different effects of the drug, i.e. 1) increases in antioxidant enzyme activities and 2) the prolongation of survival of animals, has not been directly demonstrated, the loss of both effects with the high dose of the drug in the present experiment may be taken as circumstantial evidence for their causal relationship.

Overexpression of cholecystokinin-B/gastrin receptor gene in the stomach of naturally occurring cholecystokinin-A receptor gene knockout rats

We examined the cholecystokinin (CCK)-B/gastrin receptor, H+/K+-ATPase and somatostatin gene expression, the histology and immunohistochemistry of gastrin and somatostatin of the stomach, plasma gastrin levels, and gastric acid secretion in naturally occurring CCK-A receptor gene knockout (Otsuka Long-Evans Tokushima fatty, OLETF) rats. The CCK-B/ gastrin receptor, H+/K+-ATPase and somatostatin mRNAs were determined by Northern transfer analysis. The gastric acid secretion and the plasma gastrin level were measured in vivo. The levels of CCK-B/gastrin receptor mRNA in the forestomach and the glandular stomach in OLETF rats were 2-fold higher than those of control rats, although those of H+/ K+-ATPase and somatostatin mRNAs were not different. Histological examination revealed thickening of the fundic mucosa, and hyperplasia and hypertrophy of parietal cells, although immunohistochemistry of gastrin and somatostatin revealed no significant difference from the control rats. Gastric acid secretion stimulated by gastrin or histamine was enhanced, whereas the fasting plasma gastrin level was not significantly different from that in control rats. The overexpression of CCK-B/gastrin receptor mRNA and the hyperfunction of parietal cells were observed in rats without CCK-A receptor gene expression.

Synthesis of NG-061 and its analogs, and their biological evaluation as an enhancer of nerve growth factor

A novel potentiator of nerve growth factor (NGF), NG-061, which had been isolated from the fermentation broth of Penicillium minioluteum F-4627, was synthesized from methoxybenzoquinone and phenylacetylhydrazine in a single step. A series of acyl hydrazone derivatives were also synthesized and their potentiator activity of neurotrophic effect of NGF on neurite outgrowth was evaluated by assay with a rat pheochromocytoma cell line PC12.

The diurnal rhythm of energy expenditure differs between obese and glucose-intolerant rats and streptozotocin-induced diabetic rats

Otsuka Long Evans Tokushima Fatty (OLETF) rats were developed as a model of noninsulin-dependent diabetes mellitus (NIDDM) with mild obesity. Changes in carcass composition and in the daily profile of energy expenditure were examined before and after manifestation of diabetes (8 and 24 wk, respectively), and compared with the normal control Long Evans Tokushima (LETO) rats and streptozotocin (STZ)-induced diabetic LETO rats. OLETF rats had greater body weights than LETO rats and significantly greater absolute and relative fat weights. A diurnal rhythm of energy expenditure associated with two peaks was observed in LETO rats, but the two peaks were not apparent in OLETF rats at 24 wk of age. A diurnal rhythm associated with one peak was observed in STZ-induced diabetic LETO rats. Energy derived from fat constituted this peak; the pattern of the daily energy expenditure was significantly different from that of either nontreated LETO or OLETF rats at 24 wk of age. NIDDM in OLETF rats at 24 wk of age has only a small role in modification of the diurnal rhythm of energy expenditure, whereas STZ-induced diabetes significantly affected the rhythm.

Molecular analysis of zebrafish photolyase/cryptochrome family: two types of cryptochromes present in zebrafish

BACKGROUND

Cryptochromes (CRY), members of the DNA photolyase/cryptochrome protein family, regulate the circadian clock in animals and plants. Two types of animal CRYs are known, mammalian CRY and Drosophila CRY. Both CRYs participate in the regulation of circadian rhythm, but they have different light dependencies for their reactions and have different effects on the negative feedback loop which generates a circadian oscillation of gene expression. Mammalian CRYs act as a potent inhibitor of transcriptional activator whose reactions do not depend on light, but Drosophila CRY functions as a light-dependent suppressor of transcriptional inhibitor.

RESULTS

We cloned seven zebrafish genes that carry members of the DNA photolyase/cryptochrome protein family; one (6-4)photolyase and six cry genes. A sequence analysis and determination of their in vitro functions showed that these zebrafish cry genes constitute two groups. One has a high sequence similarity to mammalian cry genes and inhibits CLOCK:BMAL1 mediated transcription. The other, which has a higher sequence similarity to the Drosophila cry gene rather than the mammalian cry genes, does not carry transcription inhibitor activity. The expressions of these cry genes oscillate in a circadian manner, but their patterns differ.

CONCLUSIONS

These findings suggest that functionally diverse cry genes are present in zebrafish and each gene has different role in the molecular clock.

Mechanism of delayed gastric emptying in naturally occurring CCK-A receptor gene knockout (OLETF) rats

We recently found a specific strain of rats (OLETF rats) in which CCK-A receptor gene expression is lacking because of a genetic abnormality. As delayed gastric emptying has been reported in this strain, we examined its mechanism. A liquid gastric load containing phenol red was administered using an orogastric tube into the stomach in OLETF and control (LETO) rats. The stomach was removed 0, 15, 30 and 45 min after meal ingestion and the content of phenol red was measured to estimate the rate of gastric emptying. Pretreatment of reserpine enhanced gastric emptying in both strains. A tenfold dose of reserpine was required in OLETF rats to induce a similar effect to LETO rats. The plasma noradrenalin level was significantly higher in OLETF than LETO rats. When the smooth muscle of the stomach was isolated and contraction in vitro was examined, the smooth muscle functions were not deteriorated in OLETF rats. The thickness of muscle determined by hematoxylin-eosin staining was not different between strains. It is suggested that the delayed gastric emptying in OLETF rats may be due to increased sympathetic nerve function.

Enhancing effect of rasagiline on superoxide dismutase and catalase activities in the dopaminergic system in the rat

Rasagiline [N-propargyl-l(R)-aminoindan] is a selective irreversible MAO-B inhibitor as is (-)deprenyl. The effect of the drug on antioxidant enzyme activities on dopaminergic tissue was examined in male F-344 rats (8.5-months-old). Two experimental groups were infused subcutaneously with rasagiline saline solutions by means of osmotic minipumps implanted subcutaneously in the back of the rats. Control animals were also similarly implanted with saline filled mini-pumps. Three-and-one-half weeks later, animals were sacrificed and selected tissue samples removed from brain, kidney and heart. Two doses of rasagiline (0.5 mg/kg/day, 1.0 mg/kg/day, both for 3.5 weeks) significantly increased catalase activities about 2-fold in substantia nigra and striatum but not in hippocampus. Interestingly, in both renal cortex and medulla. catalase (CAT) activities were significantly increased. Both Mn- and Cu,Zn-superoxide dismutase (SOD) activities were increased 2 to 4 fold in substantia nigra, striatum and renal cortex and heart. Several groups, including our own have reported an extension of survival of deprenyl-treated animals of different species. Although the mechanism(s) of the life extension by deprenyl remains unresolved, it would be interesting to investigate the effect of rasagiline on the survival of animals, since deprenyl also was shown to increase antioxidant enzyme activities in brain dopaminergic regions.

Oral administration of a synthetic trypsin inhibitor increases pancreatic duct function in CCK-A receptor-deficient rats

The effects of oral administration of a synthetic trypsin inhibitor on bicarbonate secretion were examined in cholecystokinin A (CCK-A) receptor-deficient (OLETF) rats and compared with Wistar rats. Rats were fed chow containing 0.1% trypsin inhibitor for 7 days. Rats were prepared with cannulae draining bile and pancreatic juice separately and with duodenal and extrajugular vein cannulae after 3-day trypsin inhibitor ingestion. Then the animals were maintained in Bollman cages, and the experiments were conducted 4 days after surgery. After 1.5 h of basal secretion with bile-pancreatic juice return, bile-pancreatic juice was diverted for 2 h. The responses of bicarbonate secretion to bile-pancreatic juice diversion were significantly enhanced in rats treated with trypsin inhibitor compared with those given a control diet, whereas responses of fluid and protein secretion were not affected in OLETF rats. The response of protein secretion, but not those of fluid or bicarbonate secretion, was enhanced in Wistar rats by treatment with trypsin inhibitor. Carbonic anhydrase II gene expression was increased by 7-day treatment with trypsin inhibitor only in OLETF rats, and not in Wistar rats.

Inhibitory effect of central calcitonin-gene related peptide (CGRP) on pancreatic secretion in conscious rats

The inhibitory effect of central administration of calcitonin-gene related peptide (CGRP) on pancreatic secretion stimulated by bile-pancreatic juice diversion was determined in conscious rats. Rats were prepared with separate cannulae for draining bile and pancreatic juice and with a duodenal cannula and an extrajugular vein cannula. In addition, another cannula was stereotactically implanted into the left lateral cerebral ventricle. Rats were placed in restraint cages and experiments were conducted 4 d after the operation without anesthesia. An injection of CGRP (1 nmol/10 microl) into the left lateral cerebral ventricle (i.c.v.) inhibited pancreatic secretion as well as cholecystokinin (CCK) release induced by bile-pancreatic juice diversion. Intravenous infusion of alpha- and beta-adrenergic receptor antagonist, phentolamine and propranolol did not reverse the inhibition of pancreatic secretion. Intravenous infusion of CGRP did not affect pancreatic secretion or plasma CCK concentrations. The inhibitory action of central CGRP (i. c.v.) on pancreatic secretion and CCK release stimulated by bile-pancreatic juice diversion is partially mediated by an alpha-adrenergic mechanism, although its precise mechanism has not been elucidated.

Synthesis and biological activities of lipid A-type pyrancarboxylic acid derivatives

The synthesis of lipid A-type pyrancarboxylic acid derivatives, which have a carboxylic acid group in the anomeric position of the reducing part of the disaccharide instead of the phosphate group in lipid A, is described. One of the compounds thus synthesized, which has an acyl substitution pattern similar to that of Escherichia coli lipid A, showed lipopolysaccharide (LPS)-agonistic activity. The other, which contains four lipid chains in the molecule, exhibited strong LPS-antagonistic activity toward human monoblastic U937 cells.

Lymphatic lipid transport is not impaired in ageing rat intestine

Lymphatic lipid transport in the intestine of adult and ageing rats was compared. Adult (8-10 months old) and old (24-26 months old) male Wistar rats were cannulated into the mesenteric lymph under ethrane anesthesia. On the following day, lipid emulsion containing 35.4 mg/h of olive oil was infused intraduodenally for 7 h and lymph collected hourly was assayed for triglyceride and apolipoprotein A-IV (apo A-IV). The results showed there was no difference in lymphatic lipid and apo A-IV transport between adult and old rats. Since apo A-IV synthesis in the enterocytes is linked to the intracellular assembly of lipoprotein, it is likely that in addition to lymphatic transport, production of chylomicrons is not impaired in ageing rats.

Regulation of pancreatic secretion by vagal nerve during short-term duct occlusion in conscious rats

The basal exocrine secretion of the pancreas is maintained at a constant level in conscious rats. We examined the changes in basal secretion with respect to the effect of various time periods of pancreatic duct occlusion (PDL). Male Wistar rats were prepared with cannulae that separately drained bile and pancreatic juice as well as with a duodenal cannula. Rats were placed in restraint cages, and experiments were conducted without anesthesia 4 days after the operation. Cholecystokinin (CCK) release was artificially prevented by the continuous infusion of bile with trypsin into the duodenal lumen throughout the experimental period to avoid the modification of pancreatic response by CCK. After 2-h basal collection, a pancreatic secretion was interrupted for 0.5-4 h, and then the collection of pancreatic juice was initiated again for an additional 2-4.5 h. The pancreatic secretion after the reopening of the 0.5-to 3-h PDL was comparable to basal secretion levels. However, protein secretion was significantly inhibited after the removal of 4-h PDL. Both vagotomy and capsaicin treatment abolished this inhibition, and the protein secretion after 1-h PDL in vagotomized rats increased 1.5-fold high compared with the basal value. These observations indicate that protein secretion was ceased during PDL via vagal nerve, and this may be a self-protective mechanism.

Expression of PDGF-beta receptor, EGF receptor, and receptor adaptor protein Shc in rat osteoblasts during spaceflight

A number of studies have indicated that microgravity induces osteopenia and modulates functions of mammalian cells. However, the molecular mechanisms underlying these effects of microgravity are still unknown. Rat osteoblasts were cultured for 4 and 5 days during Shuttle-Spacelab flight, and fixed by guanidine isothiocyanate solution on board after treatment with 1alpha, 25 (OH)2 vitamin D3. The mRNA levels for platelet-derived growth factor (PDGF)-beta receptor, epidermal growth factor (EGF) receptor, the growth factor receptor adaptor protein Shc, and c-fos were determined using the method of quantitative reverse transcription-polymerase chain reaction. The mRNA levels for EGF receptor were not altered by microgravity. However, the mRNA levels for PDGF-beta receptor, Shc, and c-fos were decreased to 62, 55 and 25% on the 4th day of flight, and 47, 40, and 43% on the 5th day, respectively, as compared to the corresponding ground controls. Expression of the growth factor receptor and the receptor adaptor protein was modulated in rat osteoblasts during spaceflight. Data suggest that signal transduction via growth factor receptors in rat osteoblasts is impaired by microgravity. Dysfunction of osteoblasts might be involved in spaceflight-induced osteopenia.

Different effects of trypsin inhibitors on intestinal gene expression of secretin and on pancreatic bicarbonate secretion in CCK-A-receptor-deficient rats

The effects of oral administration of two synthetic trypsin inhibitors (camostate and ONO-3403) and soybean trypsin inhibitor (SBTI) on cholecystokinin (CCK), secretin gene expression and pancreatic secretion were examined in CCK-A-receptor-deficient (OLETF) rats. The rats were fed chow containing 0.1% trypsin inhibitors for 7 days. To examine pancreatic secretion, the rats were prepared with cannulae to drain the bile and pancreatic juice separately, a duodenal cannula and an external jugular vein cannula. The animals were maintained in Bollman cages and the experiments were conducted 4 days after surgery. The levels of CCK mRNA were significantly increased by each treatment. The levels of secretin mRNA were significantly increased by camostate and SBTI, but not by ONO-3403. Bicarbonate secretion was significantly increased in rats treated with camostate and ONO-3403, but not SBTI, while protein secretion was not affected by any treatment. These observations suggest that increased bicarbonate secretion produced by synthetic trypsin inhibitors in CCK-A-receptor-deficient rats may not be due to secretin but due to ONO-3403 in the circulation.

Pharmacological modifications of endogenous antioxidant enzymes with special reference to the effects of deprenyl: a possible antioxidant strategy

Limited information is available on the upregulation of endogenous antioxidant enzymes by means of administering various pharmaceuticals and/or chemicals. It has been reported that ursodeoxycholic acid (UDCA), a bile acid originally identified from black bear bile (a Chinese medicine, Yutan) increased glutathione S-transferase (GST) activities in mouse livers, resulting in a decrease in systemic lethal toxicity of orally challenged 1-2-dichloro-4-nitrobenzene (DCNB). Also, ursolic acid found in herbal medicines (e.g. leaves of loquat) was reported to increase catalase (CAT) activities in mouse liver. Interestingly, the chemical structures of these two compounds are surprisingly similar to each other, despite the difference in their original sources. These results suggest that in the future, more and more compounds will be found to have effects on increasing endogenous antioxidant enzyme activities. Deprenyl is a monoamine oxidase B inhibitor but also possesses many other different pharmacological activities. Among these various pharmacological effects of deprenyl, a possible causal relationship between two effects of deprenyl, namely the prolongation of the survival of animals and upregulation of antioxidant enzymes in selective brain regions, has been postulated by the authors. In at least four different animal species (rats, mice, hamsters and dogs), a significant prolongation of survival by chronic administration of the drug has been reported by different groups including that of the authors. This group has reported that repeated administration of the drug for 2-3 weeks can significantly increase activities of both types of superoxide dismutase (SODs) (Cu, Zn-, and Mn-SODs) as well as of CAT selectively in brain dopaminergic regions. Both effects are dose dependent but excessive dosages become less effective and even cause an adverse effect (i.e. a decrease in enzyme activities and shortening of life span). The parallelism of the dose-effect relationship between the two phenomena suggests that modification of SOD and CAT levels is one possible mechanism for deprenyl's ability to prolong the life span of animals.

Role of CCK-A receptor in the regulation of pancreatic bicarbonate secretion in conscious rats: a study in naturally occurring CCK-A receptor gene knockout rats

Whether cholecystokinin (CCK) has a direct action on duct cells and the role of CCK-A receptor in bicarbonate secretion were examined by comparing the results obtained from OLETF (CCK-A receptor-deficient rats) and control (LETO) rats. Rats were prepared with cannulae for draining bile and pancreatic juice separately, with two duodenal cannulae and an external jugular vein cannula. The experiments were conducted without anesthesia. The responses of bicarbonate secretion to intravenous infusion of CCK, acetyl-beta-methylcholine (Ach), and 2-deoxy-D-glucose (2DG), and to intraduodenal infusion of HCl and a liquid meal were examined. To examine the synergistic effect between CCK and secretin, the effect of CCK during a background secretin infusion was examined in LETO rats. CCK did not stimulate bicarbonate secretion in either strain, nor in LETO rats with secretin infusion. When gastric acid secretion was prevented by administration of omeprazole, Ach did not increase bicarbonate secretion, but 2DG did in both strains. Intraduodenal infusion of HCI and a liquid meal significantly increased bicarbonate secretion in both strains; however, the responses were much less in OLETF than LETO rats. In conclusion, intravenous injection of CCK did not stimulate bicarbonate secretion, and the lack of CCK-A receptor decreased bicarbonate secretion in response to luminal stimulants.

Disruption of cholecystokinin (CCK)-B receptor gene did not modify bile or pancreatic secretion or pancreatic growth: a study in CCK-B receptor gene knockout mice

Pancreatic exocrine function and bile secretion were examined in cholecystokinin (CCK)-B receptor gene-targeted mice and compared among different genotypes [i.e., CCK-B receptor gene: (+/+), wild-type; (+/-), heterozygous; and (-/-), homozygous deficient]. The histology and protein concentrations in the pancreas also were examined. Amylase release from the dispersed acini was examined in vitro by using the various doses of CCK-8, carbachol, and secretin. In vivo, the bile and pancreatic juice were collected, and the concentrations of amylase and bile acid were measured in anesthetized mice. The responses to CCK (100 pmol/kg) or acetyl-beta-methylcholine (500 nmol/kg) were examined. In vitro studies showed that the maximal effective concentrations of CCK-8 (10(-l0) M), carbachol (10(-5) M), and secretin (5 x 10(-7) M) were comparable for all genotypes. Fluid, amylase, and bile acid outputs in vivo also were comparable for all genotypes. Pancreatic wet weight and protein concentrations were not significantly different, and no abnormal findings were observed on histologic examination in any genotype. These results indicated that the CCK-B receptor has no role in pancreatic growth, exocrine secretion, or bile secretion in adult mice.

Identification of new members of the GS ADP-forming family from the de novo purine biosynthesis pathway

Most living organisms can synthesize isosinate from 5-phosphoribosyl 1-pyrophosphate in the de novo purine biosynthesis pathway, which is basically composed of 10 reaction steps. Phosphoribosylglycinamide synthetase (GARS) catalyzes the second step of the pathway. We found that the enzyme shows weak, but significant, sequence similarity to phosphoribosylglycinamide formyltransferase 2 (GART2) and the ATPase domain of phosphoribosylaminoimidazole carboxylase (AIRCA), which catalyze the third and sixth steps of the pathway, respectively. In addition, the three enzymes were similar in amino acid sequence to biotin carboxylase (BC) and carbamoylphosphate synthetase (CPS), which are the members of the GS ADP-forming family. This family has been identified through a tertiary structure comparison and includes glutathione synthetase, d-alanine:d-alanine ligase, BC, succinyl-CoA synthetase beta-chain, and phosphoribosylaminoimidazole-succinocarboxamide synthase. Molecular phylogenetic analysis based on a multiple alignment of GARS, GART2, AIRCA, BC, and CPS suggests that GART2 is more closely related to AIRCA than to GARS among the three enzymes from the pathway, though the three enzymes are relatively close to each other within the GS ADP-forming family. Moreover, the analysis showed that archaeal GARS had diverged before the speciation between bacteria and eucarya.

A novel plasmid recombination mechanism of the marine cyanobacterium Synechococcus sp. PCC7002

We describe a novel mechanism of site-specific recombination in the unicellular marine cyanobacterium Synechococcus sp. PCC7002. The specific recombination sites on the smallest plasmid pAQ1 were localized by studying the properties of pAQ1-derived shuttle-vectors. We found that a palindromic element, the core sequence of which is G(G/A)CGATCGCC, functions as a resolution site for site-specific plasmid recombination. Furthermore, site-directed mutagenesis analysis of the element show that the site-specific recombination in the cyanobacterium requires sequence specificity, symmetry in the core sequence and, in part, the spacing between the elements. Interestingly, this element is over-represented not only in pAQ1 and in the genome of the cyanobacterium, but also in the accumulated cyanobacterial sequences from Synechococcus sp. PCC6301, PCC7942, vulcanus and Synechocystis sp. PCC6803 within GenBank and EMBL databases. Thus, these findings strongly suggest that the site-specific recombination mechanism based on the palindromic element should be common in these cyanobacteria.

Mechanism of the protective effects of sumac gall extract and gallic acid on the progression of CCl4-induced acute liver injury in rats

To examine the mechanism of the preventive effect of tannins on the progression of carbon tetrachloride (CCl4)-induced acute liver injury in rats, sumac gall (SG) extract and gallic acid (GA) were used as substitutes for crude tannins, because SG is a kind of Chinese traditional medicinal herb containing large amounts of various tannins, and GA is one of the major constituents of SG. The protective effect of oral (p.o.) and intraperitoneal (i.p.) administration of each substance on progression of CCl4-induced hepatitis was investigated in rats. Speculating that the superoxide dismutase (SOD)-like activities (O2 radical-scavenging activities) and/or protective effects of these substances on cell membranes might play a key role in the mechanism opposing the progression of CCl4-induced hepatitis, the O2 radical-scavenging activities in liver cells and serum in rats were monitored. Both substances significantly prevented the progression of acute liver injury with both p.o. and i.p. administration. These findings suggest that the mechanism for this prevention might be due mainly to the protective effect of these substances on cell membranes rather than O2 radical-scavenging activities.

Adenylosuccinate synthetase genes: molecular cloning and phylogenetic analysis of a highly conserved archaeal gene

Adenylosuccinate synthetase (PurA) catalyzes the first step in the de novo AMP synthesis and has been extensively studied in both Bacteria and Eukarya. We cloned the purA gene from the hyperthermophilic archaeon, Pyrococcus furiosus. The gene appears to be individually transcribed and encodes a protein of 339 amino acids. The amino acid sequence comparison with other archael PurAs found from recent genome analyses indicated that two deletions, one central and the other C-terminal, are a common feature of archaeal PurAs. None of the 21 PurA homologues analyzed from Eukarya and Bacteria exhibited this feature. Amino acid sequences of PurAs in Archaea showed 64% average identities which were significantly higher than the 50% and 55% calculated for Bacteria and Eukarya, respectively. Several residues conserved in PurAs of both Eukarya and Bacteria and shown to be of catalytic importance are missing in the archaeal PurAs. Phylogenetic analysis using PurA as the marker grouped life into 3 domains, hence it was consistent with results derived from 16-18S ribosomal RNA sequences. The topology within the three domains, in general, portrayed the hitherto accepted evolutionary relationship among the organisms utilized. PurA can, thus, serve as an additional marker to evaluate phylogenetic inferences drawn from sequence data from rRNA and other conserved genes. The presence of two unique deletions in both euryarchaeal and crenarchaeal PurAs, but not in those of Bacteria and Eukarya, is a strong evidence confirming the common lineage of these two subdomains of Archaea.

A heterodimeric DNA polymerase: evidence that members of Euryarchaeota possess a distinct DNA polymerase

We describe here a DNA polymerase family highly conserved in Euryarchaeota, a subdomain of Archaea. The DNA polymerase is composed of two proteins, DP1 and DP2. Sequence analysis showed that considerable similarity exists between DP1 and the second subunit of eukaryotic DNA polymerase delta, a protein essential for the propagation of Eukarya, and that DP2 has conserved motifs found in proteins with nucleotide-polymerizing activity. These results, together with our previous biochemical analyses of one of the members, DNA polymerase II (DP1 + DP2) from Pyrococcus furiosus, implicate the DNA polymerases of this family in the DNA replication process of Euryarchaeota. The discovery of this DNA-polymerase family, aside from providing an opportunity to enhance our knowledge of the evolution of DNA polymerases, is a significant step toward the complete understanding of DNA replication across the three domains of life.

Assessing the effects of deprenyl on longevity and antioxidant defenses in different animal models

Among many pharmaceuticals that have been tested for their effects on longevities of different animal rodents, deprenyl is unique in that its effects on longevity has been tested in at least four different animal species by independent research groups and that the effect has been postulated to be due to its effect of raising such antioxidant enzyme activities as superoxide dismutase (SOD) and catalase (CAT) in selective brain regions. Thus far, in all four species of animals examined (rats, mice, hamsters, and dogs), a positive effect was demonstrated, although the extent of its effect is quite variable. Our group has examined the effect on longevities in rats and mice and on antioxidant enzymes in rats, mice, and dogs. Although in rats of both sexes, we have obtained positive effects on longevity, two studies with different doses in mice did not reveal a significantly positive effect. We have observed, however, significantly positive effects on SOD (in Cu, Zn-, and Mn-) as well as CAT (but not glutathione peroxidase) activities in the brain dopaminergic system such as in the S. nigra and striatum (but not in hippocampus) in all rats, mice, and dogs, although the effects were quite variable, depending on the doses used. In mice, however, a long-term administration (3x/w, 3 months) caused a remarkable decrease in the magnitude of activity as well as a narrowing of the effective dose range, which may explain a relatively weak effect of the drug on mouse longevity. Further, a recent study on aging beagle dogs by Ruehl et al. showed a remarkable effect on longevity, which agrees with our SOD study in dogs. Although deprenyl has been claimed to have several other effects, such as a radical scavenging effect and a neuroprotective effect, past reports on its effects on longevities and antioxidant defenses are compatible with the notion that the drug prolongs the life span of animals by reducing the oxidative damage to the brain dopaminergic system during aging. Further, our studies on F-344 rats as well as a dog study by Ruehl et al. suggest that the drug may at least partially prolong the life span of animals by enhancing immune system function and preventing tumor development in animals.

Central somatostatin diminished inhibitory action of central CGRP on pancreatic basal secretion in conscious rats

We examined whether central somatostatin prevents an inhibitory effect of central calcitonin-gene related peptide (CGRP) on pancreatic secretion in conscious male Wistar rats (330-330 g). Rats were prepared with separate cannulas for draining bile and pancreatic juice and with a duodenal cannula and an extrajugular vein cannula. In addition, another cannula was stereotactically implanted into the left lateral cerebral ventricle. Rats were placed in restraint cages and experiments were conducted 4 days after the operation without anesthesia. An injection of CGRP (0.1, 1.0 nmol/10 microl) into the left lateral cerebral ventricle (i.c.v.) inhibited pancreatic secretion dose-dependently. To confirm the inhibitory effect of CGRP (i.c.v.) was mediated via sympathetic nerves, phentolamine was injected intravenously (i.v.) bolus (0.5 mg kg(-1)) 0.5-h before CGRP (i.c.v.), followed by continuous infusion of 0.2 mg kg(-1) h(-1). Phentolamine (i.v.) reversed the inhibition produced by CGRP (i.c.v.). An injection of 4 nmol/10 microl somatostatin (i.c.v.) 5 min prior to CGRP injection diminished the inhibitory effect of CGRP (i.c.v.). It is concluded that centrally administered somatostatin diminished the inhibitory action of CGRP (i.c.v.) on pancreatic secretion, probably via inhibiting autonomic (sympathetic) nerve excitation at the central site.

Stem cell factor mRNA expression and production in human nasal epithelial cells: contribution to the accumulation of mast cells in the nasal epithelium of allergy

BACKGROUND

In allergic rhinitis, mast cells are increased in number in the epithelium of the nasal mucosa and play an important role in the immediate response. However, the mechanism of the accumulation is not known.

OBJECTIVE

The purpose of this study was to determine whether the nasal epithelial cells produce stem cell factor (SCF), the mast cell growth and chemoattractant factor, and contribute mast cell hyperplasia in the epithelium of allergic rhinitis.

METHODS

We have characterized the cellular localization of SCF using immunohistochemistry, reverse transcribed-PCR, and ELISA; compared SCF production of cultured epithelial cells between patients with allergic rhinitis and nonallergic subjects; and compared the SCF production with the number of mast cells and the histamine content in the nasal epithelial scrapings.

RESULTS

Immunohistochemically, SCF was identified in the nasal epithelium of the biopsy specimens and in cultured nasal epithelial cells. SCF mRNA was expressed by cultured nasal epithelial cells not only in patients with allergy but also in subjects with no allergy. However, the SCF/beta-actin mRNA ratio and SCF production in day 7 cultured epithelial cells was significantly higher in allergic than in nonallergic subjects (P =. 0424, P =.0085, respectively). SCF production from nasal scrapings in culture was strongly correlated with the number of mast cells (r = 0.506, P =.0023) and the histamine content (r = 0.480, P =.0040).

CONCLUSIONS

These findings demonstrate that nasal epithelial cells produce SCF and may be important in the attraction, proliferation, and activation of mast cells in allergic inflammation in the nose.