Seroprevalence of hepatitis B and C viruses in eastern Nepal

The seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) in 303 serum samples collected from that apparently healthy population inhabitating different areas in eastern Nepal was studied. Samples were collected at Dharan Municipality, Sunsari85), Pancha Kanya Village Development Committee, Ilam86), Dhankuta Hile, Dhankuta82) and Basantapur Village Development Committee, Tehrathm50). HBsAg and anti-HBsAg antibody was screened by reverse passive haemagglutination (RPHA) and passive haemagglutination (PHA) respectively and positivity was confirmed by enzyme linked immunosorbent assay (ELISA). Anti-HCV antibody was detected by ELISA. None of the samples were positive for HBsAg. Anti-HBsAg antibody was positive in 1.9% (6/303). The positive rate increased with age reaching 25% positivity among the elderly. The anti-HBsAg antibody positivity was 2.35, 2.32, 1.22 and 2.00 in Dharan, Ilam, Dhankuta and Tehrathum respectively Anti-HCV antibody was detected only in one sample (15-year-old boy) collected in Dharan. These findings indicate that the HBV and HCV infections are not active in eastern Nepal.

A genetic linkage map of the mouse using restriction landmark genomic scanning (RLGS)

We have developed a multiplex method of genome analysis, restriction landmark genomic scanning (RLGS) that has been used to construct genetic maps in mice. Restriction landmarks are end-labeled restriction fragments of genomic DNA that are separated by using high resolution, two-dimensional gel electrophoresis identifying as many as two thousand landmark loci in a single gel. Variation for several hundred of these loci has been identified between laboratory strains and between these strains and Mus spretus. The segregation of more than 1100 RLGS loci has been analyzed in recombinant inbred (RI) strains and in two separate interspecific genetic crosses. Genetic maps have been derived that link 1045 RLGS loci to reference loci on all of the autosomes and the X chromosome of the mouse genome. The RLGS method can be applied to genome analysis in many different organisms to identify genomic loci because it uses end-labeling of restriction landmarks rather than probe hybridization. Different combinations of restriction enzymes yield different sets of RLGS loci providing expanded power for genetic mapping.

Inhibition of ATP-sensitive K+ channel by a non-sulfonylurea compound KAD-1229 in a pancreatic beta-cell line, MIN 6 cell

We studied the mechanism of action of KAD-1229, a non-sulfonylurea compound shown to stimulate insulin secretion, in a glucose responsive insulinoma cell line, MIN 6 cells. In microsomal fraction of MIN 6 cells, KAD-1229 displaced binding of [3H]glibenclamide in a concentration-dependent manner. The dissociation constant and the maximum binding capacity were 0.61 nM and 8.70 pmol/mg.protein, respectively. In inside out configuration of patch-clamp technique, KAD-1229 attenuated the opening of ATP-sensitive K+ channels. The effect of KAD-1229 was detected at 10(-8) M, and 10(-5) M KAD-1229 almost completely blocked the activity of ATP-sensitive K+ channel. When membrane potential was monitored by a perforated mode of patch clamp, KAD-1229 induced depolarization of plasma membrane, which was followed by a burst of action potentials. These action potentials were blocked by cobalt. In a fura-2-loaded single MIN 6 cell, KAD evoked an elevation of intracellular free Ca2+ concentration, [Ca2+]i. The KAD-1229-mediated elevation of [Ca2+]i was attenuated by either removal of extracellular Ca2+ or an addition of nifedipine. Finally, KAD-1229 augmented insulin secretion in MIN 6 cells in a concentration-dependent manner. KAD-1229 also enhanced the effect of glucose and nifedipine inhibited the action of KAD-1229 on insulin secretion. These results indicate that KAD-1229 stimulates insulin secretion by stimulating Ca2+ influx and that, despite the lack of sulfonylurea structure, KAD-1229 binds to sulfonylurea receptors and inhibits the activity of ATP-sensitive K+ channel in MIN 6 cells.

Angiotensin II type 1 receptor messenger RNA levels in human blood cells of patients with primary and secondary hypertension: reference to renin profile

OBJECTIVES

The relationship between plasma renin activity, plasma angiotensin II (Ang II) or aldosterone levels and peripheral blood cells (mononuclear leucocytes and platelets) Ang II type 1 (AT1) receptor messenger RNA (mRNA) levels were examined in both primary and secondary hypertensive patients.

DESIGN AND METHODS

The subjects were 30 patients with primary hypertension, five with primary aldosteronism, five with renovascular hypertension and five normotensive controls with renal cell carcinoma. Blood was collected from each patient for estimation of plasma renin activity and plasma Ang II and aldosterone concentrations, and for isolation of mononuclear leucocytes and platelets, which were then used to measure AT1 receptor mRNA with reverse-transcription polymerase chain reaction.

RESULTS

Platelet AT1 receptor mRNA levels were inversely correlated with plasma Ang II levels, and mononuclear leucocyte receptor mRNA levels were positively correlated with plasma Ang II levels in patients with primary hypertension. In contrast, in secondary hypertension both platelets and mononuclear leucocytes AT1 receptor mRNA, which were elevated, were reduced after removal of the adrenal tumour or correction of stenosis of the renal artery.

CONCLUSIONS

Platelet AT1 receptors, which were used to reflect physiologically important sites such as vascular smooth muscle, were shown to be regulated in a different manner from mononuclear leucocyte receptors. In patients with primary aldosteronism and renovascular hypertension the plasma aldosterone level was shown to be an important factor upregulating AT1 receptor mRNA.

Immunoglobulin M and G antibodies in mice in response to Toxoplasma gondii (S-273) infection and their antigen recognition patterns in western blotting on various post-infection days

Immunoglobulin M and G antibody responses in mice experimentally infected with Toxoplasma gondii (S-273) and the reaction patterns with T. gondii (RH) tachyzoite antigens were studied on various post-infection days (PIDs) (2nd to 36th PIDs) using a commercially available IgM and IgG enzyme linked immunosorbent assay (ELISA) test systems and Western blotting (WB) technique. IgM antibody in ELISA test appeared to be positive on 12th PID (absorbance 0.764) and reached its peak level on 16th PID (absorbance 1.338) showing a slow decline thereafter with an absorbance of 0.800 even on 36th PID. Positivity of IgM was confirmed by WB except for 36th PID. IgG appeared on 16th PID with an absorbance of 0.248 and showed a steady increasing tendency even on 36th PID (absorbance 1.747). However, IgG positivity on WB was observed only on 29th PID and afterwards. On Western blots, both IgM and IgG showed interesting antigen recognition patterns on various PIDs. At the most IgM recognised seven antigens of 14kDa to 53kDa while IgG recognised eight antigens of 17kDa to 53kDa. Major antigens recognised by IgM were of 53kDa and 21kDa while the major band recognised by IgG was of 19kDa. The major bands, however, showed variability in their consistency during various PIDs. All the antigens recognised by IgM and IgG were not identical.

Purification and characterization of alanine dehydrogenase from a cyanobacterium, Phormidium lapideum

Alanine dehydrogenase (AlaDH) was purified to homogeneity from cell-free extracts of a non-N2-fixing filamentous cyanobacterium, Phormidium lapideum. The molecular mass of the native enzyme was 240 kDa, and SDS-PAGE revealed a minimum molecular mass of 41 kDa, suggesting a six-subunit structure. The NH2 terminal amino acid residues of the purified AlaDH revealed marked similarity with that of other AlaDHs. The enzyme was highly specific for L-alanine and NAD+, but showed relatively low amino-acceptor specificity. The pH optimum was 8.4 for reductive amination of pyruvate and 9.2 for oxidative deamination of L-alanine. The Km values were 5.0 mM for L-alanine and 0.04 mM for NAD+, 0.33 mM for pyruvate, 60.6 mM for NH4+ (pH 8.7), and 0.02 mM for NADH. Various L-amino acids including alanine, serine, threonine, and aromatic amino acids, inhibited the aminating reaction. The enzyme was inactivated upon incubation with pyridoxal 5'-phosphate (PLP) followed by reduction with sodium borohydride. The copresence of NADH and pyruvate largely protected the enzyme against the inactivation by PLP.

[The monitoring of cytomegalovirus antigenemia and arterial oxygen saturation for the early detection of cytomegalovirus pneumonia]

Eighteen patients underwent allogeneic bone marrow transplantation (allo. BMT) during the period May, 1991 to December, 1992 in the Center for Adult Diseases, Osaka. They were monitored for cytomegalovirus (CMV) antigenemia and arterial oxygen saturation (SaO2). More than 10 antigen-positive cells per 50,000 polymorphonuclear leukocytes were detected in five of 18 patients. Three of these 5 patients developed CMV pneumonia several weeks after the first detection of more than 10 positive cells. Six of 18 patients developed interstitial pneumonia (IP) (3 CMV pneumonia and 3 idiopathic IP). SaO2 decreased less than 95% several days before the development of IP in 3 of these 6 patients (2 of CMV pneumonia and 1 of idiopathic IP). CMV antigenemia assay and SaO2 assay were thus both considered to be useful for the early detection or prediction of development of CMV pneumonia.

[A comparison of preventive health behaviors among middle-aged males in different types of communities in Tokyo]

Preventive health behaviors of middle-aged men living in areas of Tokyo with differing mortality rates were analyzed to determine if regional differences exist and if so why. Information on seven different health behaviors (cigarette smoking, physical activity, alcohol consumption, food intake pattern, taking breakfast, hours of sleep, and relative weight) were obtained by a survey among the sample randomly selected from men 35 to 64 years of age living in two separate communities, Koto-Ward with a high middle-aged male mortality and Bunkyo-Ward where it is low. The following results were obtained; 1) In Koto-Ward where middle-aged male mortality is high, the proportion of interviewees who participated physical activity more than once a week and had good food intake patterns was significantly lower than in Bunkyo-Ward. 2) Regional differences in both physical activity and food intake pattern appear to be due to differences in proportion of higher educational attainment which is associated with more frequent participation in physical activity and better food intake patterns.

Activation of PKN, a novel 120-kDa protein kinase with leucine zipper-like sequences, by unsaturated fatty acids and by limited proteolysis

PKN, a novel protein kinase with catalytic domain homologous to PKC family and unique amino terminal leucine zipper-like sequences, was purified partially from COS7 cells transfected with the cDNA construct encoding human PKN for enzymatic characterization of the enzyme. Using serine containing synthetic peptides based on PKC pseudosubstrate sites as the phosphate acceptors, kinase activities estimated from partially purified PKN were not stimulated by Ca2+/phosphatidylserine/diolein but were activated several-fold to several tens-fold by 40 microM unsaturated fatty acids, such as arachidonic acid, linoleic acid, and oleic acid. Autophosphorylation of the immunoprecipitates using anti-PKN antiserum was also stimulated by various unsaturated fatty acids. Limited proteolysis of PKN with trypsin induced an enhancement of the peptide kinase activity that was almost independent of arachidonic acid.

[Social intergration and change in activities of daily living in Japanese elderly]

The prospective association of social integration reported in 1987 with change in activities of daily living (ADL) over three years was examined in a cohort of 2200 Japanese elderly, aged 60 years and over. Social integration data was obtained from a national survey which measured both the quantity and frequency of attachment. Social ties were classified into five types: spouse, child(ren) living together, child(ren) living separately, friend, neighbor, and community group. Eight potential confounding variables--age, educational attainment, existence of chronic diseases, subjective well-being, drinking, sleeping hours, cigarette smoking, and exercise--were controlled using logistic regression analysis for each sex. Men who attended community group meetings more frequently had significantly less decline in ADL during the follow-up period for those who were ADL unimpaired at the baseline survey, and were also significantly more improved for those who were ADL impaired people at the baseline survey. Trends for women were not significant.

[Precision and measurement errors in bone mineral density by dual energy x-ray absorptiometry in mass health examination]

Decreasing mortality and the low birth rates has resulted in a high rate of increase in the elderly population in Japan. Increases in osteoporosis and its complication (fractures) are inevitable among the Japanese elderly. The Ministry of Health and Welfare of Japan and other municipalities are in the process of developing standards for noninvasive and quantitative assessment of bone minerals in mass health examinations in order to prevent osteoporosis fracture in elderly females. Dual energy x-ray absorptiometry (DXA) has undergone development to significantly improve scan speed, image resolution and precision with relatively low exposure to x-rays, and is now considered one of the most suitable instruments to measure bone mineral density (BMD) in both clinical and mass-screening for osteoporosis in population-based mass health examinations in Japan. The purpose of the present study using DXA fixed in a mobile van are: 1) to compare the precision of anteroposterior (AP) and lateral (LT) projections of the lumbar region, and three areas of the proximal femur (neck: NK, trochanter: TR, Ward's triangle: WD); 2) to analyze the physical factors influencing the precision; 3) to study the magnitude of intra- and inter-observer measurement errors and of different sets of regions of interest (ROI) in LT projection; and 4) to examine which measurement items should be selected in mass health examination in order to minimize measurement errors particularly for longitudinal observational study. Results are as follow: 1) Precision estimated by the reproducibility of measurements in the spine phantom bone were relatively good in both short and long terms. However, in female volunteers, precision of LT-BMD was remarkably inferior to that for AP-BMD and the three BMD of the proximal femoral region. Among the physical characteristics, body mass index and menopausal state were significantly associated to the precision of LT-BMD. 2) Regarding the correlations of BMD in the same region, all correlation coefficients except LT-BMD (r = 0.65) exceeded 0.97. Intra-regional BMD showed that correlations when including LT-BMD were significantly lower than the other correlations with LT-BMD excluded. 3) Concerning the magnitude of observational errors in both intra- and inter-observer measurements, LT-BMD showed the largest measurement error, largely due to lack of consensus in the ROI setting for the vertebral body and to the instability of positioning when lateral scanning was carried out.(ABSTRACT TRUNCATED AT 400 WORDS)

[Significance of serological genotyping of hepatitis C virus in Japanese patients with chronic liver disease due to hepatitis C]

Recently, T-Kohara et al. reported that most hepatitis C virus (HCV) in Japan can be classified into two groups, group 1 (G-1) and group 2 (G-2), on the basis of the NS4 region nucleotide sequence. Using a genetic engineering method, they developed a new assay in which antibodies against group specific recombinant proteins of the NS4 region were measured by ELISA (Serological Genotype, Serotype). In the present study, we examined 100 patients with chronic liver disease due to hepatitis C. The sensitivity of this assay was 98.0% (98/100). The HCV serotype distribution was 74/100 (74.0%) for serotype G-1, 22/100 (22.0%) for serotype G-2, 2/100 (2.0%) for both being positive and 2/100 (2.0%) for indeterminate. The distribution of G-1 was significantly higher than that of G-2 (p < 0.05), however, we found no difference between the distribution of G-1 and that of G-2 in age, sex, history of blood transfusion or type of liver disease. In the same serum samples, we performed HCV genotyping by reverse transcription polymerase chain reaction (RT-PCR) using type specific primers derived from the NS5 region of HCV to verify the specificity of such serotyping. The sensitivity of genotyping by RT-PCR was 88.0% (88/100). The HCV genotypes determined by both methods were consistent in 86.0% (86/100) of cases, and were not contradictory in any sample. These data indicated that serological genotyping was more sensitive and was consistent with genotyping by RT-PCR. Therefore, we consider the method useful for epidemiologic studies of HCV in Japan.

Terminal distribution of projections from the retrosplenial area to the retrohippocampal region in the rat, as studied by anterograde transport of biotinylated dextran amine

The terminal distribution of projections from the retrosplenial area to the retrohippocampal region was examined in the rat with anterograde transport of biotinylated dextran amine. Projections from the retrosplenial granular area (RSG) to the retrohippocampal region terminate predominantly ipsilaterally in layers I, III, V and VI of the presubiculum, layers I and IV-VI of the parasubiculum, the molecular and pyramidal cell layers of the subiculum, and layers I, III, V and VI of the entorhinal area. On the other hand, projections from the retrosplenial agranular area (RSA) terminate predominantly ipsilaterally in layers I and III of the presubiculum and layers V and VI of the entorhinal and perirhinal areas, and ipsilaterally in layers IV-VI of the parasubiculum. The results show that projections from the RSG to the retrohippocampal region are as massive as those from the RSA, and that each retrosplenial area has distinct projection fields in the retrohippocampal region. This suggests that each retrosplenial area may play some distinct functional roles in memory and learning processes such as spatial behavioral learning.

Manganese ions induce tonic contraction after relaxation in a high-K+ medium in ileal longitudinal smooth muscle of guinea-pig

In ileal longitudinal muscle 5 mM Mn2+ inhibited completely the K+ (60 mM)-induced tonic tension to the base line; however, the tension progressively increased to above the level of original tonic response evoked by K+ after 3 h in the presence of Mn2+. Tetrodotoxin 5 x 10(-5) M) had no influence on the tension development in the presence of Mn2+ in the high-K+ medium. Mn2+ also increased the tension in a high-K+, Ca(2+)-free medium. The Ca2+ antagonist, gallopamil (10(-6) M) inhibited the development of tension in the presence of Mn2+ in the high-K+ medium. The 45Ca uptake determined by the lanthanum method remained unchanged from control levels after 3 h of the 5 mM Mn2+ application in the high-K+ medium in spite of the development of the tension. The manganese uptake in the high-K+ medium, increased in accordance with the increase of duration of 5 mM Mn2+ application. Gallopamil inhibited manganese uptake in the high-K+ medium. These results suggest that Mn2+ firstly reduces K(+)-induced tension by inhibition of Ca2+ influx, subsequently, Mn2+ ions accumulate in the intracellular compartments through voltage-operated Ca2+ channels and may activate contractile proteins in the ileal muscle.

Seroepidemiological study of toxoplasmosis in two different geographical areas in Nepal

A total of 302 serum samples collected from Chitawan (159) and Mustang (143) districts of Nepal were included in this study. Anti-toxoplasma antibody was detected using micro-latex agglutination (MLA) and ELISA methods. An overall positive rate was found to be 57.9%. The positive rate in Chitawan was significantly higher (64.1%) (less than 1,000 m altitude) compared to that in Mustang (51.0%) (more than 3,000 m altitude) (p < 0.05). Females in Chitawan showed significantly higher positive rate (71.2%) compared to males (56.9%) (p < 0.05). On the contrary, though insignificantly, males showed higher positive rate (57.9%) compared to that of females (43.3%) in Mustang. Almost equal positive rate was observed among males in both study area. Females in Chitawan showed significantly higher (71.2%) positive rate compared to their counterparts in Mustang (43.3%) (p < 0.001). A slight increase in positive rate with age was observed in Chitawan while in Mustang a decreasing trend was noticed. Ethnically though statistically not significant, Indo-Aryans showed a higher positive rate (69.2%) compared to the positive rate shown by Tibeto-Burmans (63.1%) in Chitawan while the reverse was true in Mustang (Tibeto-Burmans: 53.8% and Indo-Aryans: 38.4%). Interestingly, 2.9% and 1.3% of MLA positive samples showed toxoplasma IgM antibody. None of the IgM positive samples were positive for toxoplasmic antigens.

[Detection of thymidylate synthase mRNA in 5-fluorouracil resistant human colon adenocarcinoma cells]

To investigate the resistance against 5-fluorouracil (FU), thymidylate synthase (TS) mRNA level was measured by reverse transcription PCR (RT-PCR) technique and quantitated by a competitive-PCR method in human colon adenocarcinoma cell line, SNU-C1 and its FU resistant cell line, C1/FU. Using a set of primers covering 3'-untranslated region of mRNA, PCR products were amplified from cDNAs prepared from both SNU-C1 and C1/FU. However, only a cDNA extracted from C1/FU was amplified in a stationary growth phase. Then, the amount of mRNA was quantitated by competitive-PCR technique in both cell lines using another set of primer enable to amplify product in both stationary and logarithmic cell growth phase. The amount of mRNA in C1/FU was four times more than that of C1. The gene level in TS gene in genome DNA in these cell lines were not different incidentally. These data suggest that TS mRNA was more increased and can be more stable in C1/FU, accounting for FU resistance.

Rate of falls and the correlates among elderly people living in an urban community in Japan

Eight hundred and seven elderly persons aged 65-84 years who were randomly selected from the community were interviewed about falls. The rate of falls in the preceding year was 12.8% in men and 21.5% in women. The difference in the rate between the sexes was statistically significant. The rate in the older group was significantly higher than that in the younger group in both sexes, when they were divided into two major age categories. Multivariate logistic regression analysis showed that contact with a doctor within a month preceding the survey in both sexes, age, history of stroke, visual deficit in men, and urinary or bowel incontinence in women were significantly associated with increased risk of falling. The study reveals that falls tend to occur in physically frail elderly people in the community.

Quantitative analyses of the structure-hydrophobicity relationship for N-acetyl di- and tripeptide amides

The partition coefficient (P) of neutral species and the apparent partition ratio (P') at pH 7 of the ionized form were measured with the 1-octanol/water system for a number of N-acetyl di- and tripeptide amides having un-ionizable and ionizable side chains. Their log values were studied in terms of free-energy-related substituent and substructural parameters using regression analysis to give correlation equations of high quality physicochemically as well as statistically. The intrinsic hydrophobicity of side-chain substituents and their steric effect on the relative solvation of the backbone CONH groups were significant in determining the log P values of the un-ionizable acetyl peptide amides. For the log P value of peptides with polar side-chain substituents, respective indicator variable terms were required to account for the sum of specific effects of substituents such as intramolecular hydrogen-bond formation and the "polar proximity factor" for augmentation of the hydrophobicity. For the log P'(pH 7) value of basic and acidic peptides, the ability of counterionic species to form ion-pairs, the change in the apparent hydrophobicity of ionizable groups from the intrinsic value for their nonionized forms, the effect of ion-pairing itself, and other effects were additionally considered. From the regression coefficients of the parameter terms in correlation equations an effective hydrophobicity index was defined for each side chain, and the application and its limitation were suggested.

[Inhibitory mechanism of experimental stress ulcer in spontaneously hypertensive rats (SHR) from the view point of mucosal blood flow]

Stress ulcer formation is reportedly much less frequent in SHR than in normotensive control rats (Wistar Kyoto Rat: WKY). The purpose of this study was to investigate the mechanism of maintenance of gastric mucosal blood flow (GMBF) during imposed stress in SHR. In stressed-only SHR, GMBF did not significantly change during water immersion and restraint conditions and ulcer index (UI) was significantly lower than that of WKY. Stress conditions led to a fall in blood pressure and a gradual fall in heart rate in WKY and SHR. It was assumed that the changes in blood pressure and heart rate during stress were due to vagal hyperfunction. The catecholamine level in the fundic gland of the gastric tissue was higher in the non-stressed SHR than in the non-stressed WKY. The administration of 6-hydroxydopamine to SHR produced a significant reduction in GMBF during stress conditions and UI was significantly higher in this group than in the stressed-only SHR. In SHR treated with nifedipine, UI was lower than that of the control group and GMBF showed no significant change compared with the stressed-only SHR. However, the administration of verapamil produced a significant reduction in GMBF during stress conditions and increased UI. The norepinephrine and dopamine levels of the groups treated with verapamil were significantly lower than those in the groups treated with nifedipine. These results suggest that local regulation of gastric mucosa mediated by sympathetic hyperfunction in SHR is more important for the maintenance of GMBF during stress conditions than changes in peripheral artery resistance.

The presence of low molecular weight germinative substances in Bacillus cereus T spore extract

An extract from intact spores of Bacillus cereus T having a germination-inducing activity was studied. Two distinct germinative principles were found through dialysis of the extract. One was diffusible through the dialysis membrane and the other was non-diffusible. The activity of the former fraction was inhibited by the addition of 1 mM glycoletherdiamine-N,N,N',N'-tetraacetic acid (GEDTA), whereas the latter fraction was inactive unless GEDTA was added to the assay system. The diffusible principle maintained the major portion of the activity found in the crude spore extract. By means of high-performance liquid chromatography (HPLC) using a gel permeation chromatography column, 9 fractions were obtained from the deproteinized diffusible fraction. Of those fractions, two fractions (No. 1 and No. 8) were responsible for the germination-inducing activity, but no reconstituted activity was observed unless both fractions No. 1 and No. 8 were added to the assay system. Amino acid analysis of fraction No. 1 revealed that the fraction was rich in free amino acids, especially in alanine. On the other hand, by the use of reverse-phase HPLC and fast atom bombardment mass spectrometry, it was concluded that the effective substance in fraction No. 8 was inosine. Based on these findings, it was suggested that the active substances in fraction No. 1 might be a free amino acid such as L-alanine and/or Ca2+ and a Ca(2+)-binding substance.

A comparative study of the enzymological features of alpha-amylase in the Drosophila melanogaster species subgroup

A comparative study was done on the enzymological features of alpha-amylase among six sibling species belonging to the Drosophila melanogaster species subgroup. The pH optima were 7.6 for D. melanogaster, D. mauritiana and D. simulans and 7.4 for D. erecta, D. teissieri and D. yakuba. The temperature optima were commonly 37 C in all species studied. However, there are two types of temperature dependence; a strict one as observed in D. melanogaster, D. mauritiana and D. simulans, and a flat one as observed in D. erecta, D. teissieri and D. yakuba. These separations are consistent with the general phylogeny within this species subgroup. The substrate dependence was almost the same in all the species studied. The Vmax and Km were also estimated for each species. We found clear differences in the enzymological features between the species. Thus these differences might reflect an adaptation of the amylase enzyme system to speciation in this species subgroup.