Central Region Of Japan Research Articles

Identifying Spatial Variation of Carbon Stock in a Warm Temperate Forest in Central Japan Using Sentinel-2 and Digital Elevation Model Data

The accurate estimation of carbon stocks in natural and plantation forests is a prerequisite for the realization of carbon peaking and neutrality. In this study, the potential of optical Sentinel-2A data and a digital elevation model (DEM) to estimate the spatial variation of carbon stocks was investigated in a mountainous warm temperate region in central Japan. Four types of image preprocessing techniques and datasets were used: spectral reflectance, DEM-based topography indices, vegetation indices, and spectral band-based textures. A random forest model combined with 103 field plots as well as remote sensing image parameters was applied to predict and map the 2160 ha University of Tokyo Chiba Forest. Structural equation modeling was used to evaluate the factors driving the spatial distribution of forest carbon stocks. Our study shows that the Sentinel-2A data in combination with topography indices, vegetation indices, and shortwave-infrared (SWIR)-band-based textures resulted in the highest estimation accuracy. The spatial distribution of carbon stocks was successfully mapped, and stand-age- and forest-type-level variations were identified. The SWIR-2-band and topography indices were the most important variables for modeling, while the forest stand age and curvature were the most important determinants of the spatial distribution of carbon stock density. These findings will contribute to more accurate mapping of carbon stocks and improved quantification in different forest types and stand ages.

Restoration Contributes to Maintain Ecosystem Services and Bio-Cultural Linkages Between Wetlands and Local Communities: a Case from a Botanical Diversity Hotspot in Japan.

The online version contains supplementary material available at 10.1007/s13157-022-01639-2.

Combining Dynamical and Statistical Modeling to Improve the Prediction of Surface Air Temperatures 2 Months in Advance: A Hybrid Approach

A new type of hybrid prediction system (HPS) of the land surface air temperature (SAT) is described and its skill evaluated for one particular application. This approach utilizes sea-surface temperatures (SST) forecast by a dynamical prediction system, SINTEX-F2, to provide predictors of the SAT to a statistical modeling system consisting of a set of nine different machine learning algorithms. The statistical component is aimed to restore teleconnections between SST and SAT, particularly in the mid-latitudes, which are generally not captured well in the dynamical prediction system. The HPS is used to predict the SAT in the central region of Japan around Tokyo (Kantō) as a case study. Results show that at 2-month lead the hybrid model outperforms both persistence and the SINTEX-F2 prediction of SAT. This is also true when prediction skill is assessed for each calendar month separately. Despite the model's strong performance, there are also some limitations. The limited sample size makes it more difficult to calibrate the statistical model and to reliably evaluate its skill.

Impacts of Flood Disturbance on the Dynamics of Basin-Scale Swimming Fish Migration in Mountainous Streams

This study investigated the response of sweetfish (Plecoglossus altivelis), a species that migrates dynamically throughout a river basin, to two flood events during the summer of 2020 in the Nagara River, located in the central region of Japan. By combining multiple environmental DNA (eDNA) surveys and hydrological modeling, the spatiotemporal distribution of P. altivelis throughout a mountainous river basin was captured and analyzed. The eDNA concentrations at 42 sites in the Nagara River Basin were analyzed five times from August to early October 2020. In addition, Rainfall–Runoff–Inundation model calculations were performed using 1-km resolution precipitation data as input values to analyze the magnitude of the flood disturbance at the eDNA sites. The daily specific discharge Qs (m3/s/km2) was employed as an index of the flood magnitude. The calculation period included Flood Events 1 and 2 with 52 and 38 days of precipitation reaching 1923 and 528 mm, respectively. The results of the eDNA analysis showed that, immediately after Flood Event 1, the spatial distribution of P. altivelis was unevenly distributed in the upper reaches of the Nagara River and some of its tributaries. Subsequently, the distribution expanded to the entire mainstem. The distribution of the maximum daily specific discharge suggested that the river segments with high eDNA concentrations of P. altivelis immediately after the high-magnitude flood event were those with a relatively low intensity of flood disturbance compared with those in the other connected river segments and tributaries. The results of this study indicate that the resilience of riverine communities to extreme floods is supported by the continuity and connectivity between the mainstem and its tributaries in mountainous river basins.

Vulnerability analysis of cut-capacity structure and OD demand using Gomory-Hu tree method

Vulnerability analysis of transportation networks has rapidly become important in recent decades given the increasing numbers of transportation disasters. In this paper, we describe a method for calculating the minimum cuts between all pairs of nodes in a transportation network and develop two indices for analyzing vulnerability; these are derived from topology-based vulnerability/demand-accountable analyses and enable evaluation of cuts without assuming route-choice behaviors. We show that such analyses can be performed using a Gomory–Hu tree to reduce the computational load. This method is efficient, requiring only N − 1 calculations of the maximum flow problem even though the number of node pairs is N2, where N is the number of nodes. In addition, we show that the total demand passing each minimum cut, which is necessary for demand-accountable analysis, can be obtained by network loading onto the tree using the Gomory–Hu tree features. We apply the proposed method to the central region of Japan to illustrate the applicability of the two indices for identifying vulnerable links in the road network.

A 15-year study on the relationship between beech (Fagus crenata) reproductive-organ production and the numbers of nuisance Japanese black bears (Ursus thibetanus japonicus) killed in a snowy rural region in central Japan

A 15-year study on the relationship between beech (Fagus crenata) reproductive-organ production and the numbers of nuisance Japanese black bears (Ursus thibetanus japonicus) killed in a snowy rural region in central Japan

How did the characteristics of the growing season change during the past 100 years at a steep river basin in Japan?

The effects of climate change on plant phenological events such as flowering, leaf flush, and leaf fall may be greater in steep river basins than at the horizontal scale of countries and continents. This possibility is due to the effect of temperature on plant phenology and the difference between vertical and horizontal gradients in temperature sensitivities. We calculated the dates of the start (SGS) and end of the growing season (EGS) in a steep river basin located in a mountainous region of central Japan over a century timescale by using a degree-day phenological model based on long-term, continuous, in situ observations. We assessed the generality and representativeness of the modelled SGS and EGS dates by using phenological events, live camera images taken at multiple points in the basin, and satellite observations made at a fine spatial resolution. The sensitivity of the modelled SGS and EGS dates to elevation changed from 3.29 days (100 m)-1 (-5.48 days °C-1) and -2.89 days (100 m)-1 (4.81 days °C-1), respectively, in 1900 to 2.85 days (100 m)-1 (-4.75 days °C-1) and -2.84 day (100 m)-1 (4.73 day °C-1) in 2019. The long-term trend of the sensitivity of the modelled SGS date to elevation was -0.0037 day year-1 per 100 m, but the analogous trend in the case of the modelled EGS date was not significant. Despite the need for further studies to improve the generality and representativeness of the model, the development of degree-day phenology models in multiple, steep river basins will deepen our ecological understanding of the sensitivity of plant phenology to climate change.

A New Species of Pseudostrandesia Savatenalinton and Martens, 2009 (Ostracoda, Crustacea) Collected from Two Pet Shops in Central Japan: an Alien Species?

An undescribed species of freshwater ostracod belonging to the genus Pseudostrandesia Savatenalinton and Martens, 2009 was collected from two pet shops in the Kanto region of central Japan. This species, herein named Pseudostrandesia tenebrarum sp. nov., is similar to four species previously reported from Southeast Asia, but can be distinguished by carapace and appendage features. It is the second species of the genus for which males are known. Of the nine previously described species in the genus, one is exclusively known from Turkey, and the others are found in Southeast Asia and the vicinity, one of which is also recorded in India and east China. There are two scenarios to explain the existence of Pseudostrandesia tenebrarum sp. nov. in pet shops in Japan: it is either native to Japan but has yet to be discovered in its natural habitat, or it is an alien species, perhaps unwittingly imported with plants or fish for the pet trade. We review the likelihood of both scenarios, and conclude that although there is insufficient evidence to be sure, it is potentially an alien species in Japan. The most likely origin is Southeast Asia, as evidenced by its close morphological resemblance to particular Southeast Asian species. Juveniles as well as adults were recovered, indicating that this species is reproducing in the pet trade, supporting the notion that it has invasive potential to areas outside of its natural range. The description and report of this species highlights a possible introduction of an alien species to Japan, and facilitates further monitoring.

Field Study on Nationality Differences in Adaptive Thermal Comfort of University Students in Dormitories during Summer in Japan

A summer field study was conducted in two university dormitories in the Tokai region of Central Japan. The study aimed at understanding the correlation between subjective thermal responses as well as whether nationality was affecting the responses. It was observed that nationality significantly affected thermal sensitivity and preference. The occupants’ acceptance for thermal stress was invariably above 90%. Despite the high levels of humidity observed, the multiple regression model showed that only the indoor air temperature was significant for explaining the variability of thermal sensation for both Japanese and non-Japanese students. The highest probability of voting neutral for university students in dormitory buildings in the Tokai region of Japan was estimated within 24~26.5 °C (by probit analysis). Japanese students were more sensitive to their indoor environment as opposed to the international students. The adjusted linear regression coefficient yielded from the room-wise day-wise averages were 0.48/K and 0.35/K for Japanese sensitivity and international sensitivity, respectively. In our study, the Griffiths’ model of estimating comfort temperature (or thermal neutrality) showed weak predictability and notable differences from the actually voted comfort. The neutral and comfort temperature observed and estimated in the study remained invariably below the recommended temperature threshold for Japan in summer leading to believe that that threshold is worth reevaluating.

Chemical Characteristics of Cloud Water and Sulfate Production Under Excess Hydrogen Peroxide in a High Mountainous Region of Central Japan

Over the last two decades, atmospheric sulfur dioxide (SO2) concentrations have decreased in air-polluted regions. However, this decrease was accompanied by a rise in cloud water acidity (pH), which remains below 5. With this change, gas-phase hydrogen peroxide (H2O2) exceeded SO2 in most of these regions. These conditions where SO2 10) in our observation site, which was due to power plant restrictions in Japan since the 1970s. The ion species concentrations in cloud water indicated that cloud acidification resulted from dissolution of gaseous HNO3 and SO2, whereas gaseous hydrochloric acid and organic acid had a minor contribution to the acidification. Significant losses of Cl− and Mg2+ were observed in some of the cloud water. The excess value of non-sea-salt sulfate (nss-SO42−) over NH4+ in cloud water implies the in-cloud oxidation of gaseous SO2 to aqueous SO42−. A Se tracer technique was used to conduct in-situ measurements of in-cloud SO42− production. The results showed that the in-cloud production varied in a range between 7 ± 2 and 41 ± 14%. This temporal variation might be due to ambient SO2 concentrations based on Henry’s law.

Archaeological significance and chemical characterization of the obsidian source in Kirigamine, central Japan: Methodology for provenance analysis of obsidian artefacts using XRF and LA–ICP–MS

The Kirigamine area is one of the major obsidian sources in the Chubu-kanto region of central Japan, and is regarded as an important archaeological study area for improving the understanding of historical changes in human–environment interactions related to obsidian procurement activities during the Upper Paleolithic. Previous studies have presented a model for the relationship between human activities and the paleoenvironment, but there is a need for further understanding based on data related to the sourcing of obsidian in the Kirigamine area. This study aimed to establish a method for provenance analysis of obsidian artefacts based on chemical compositions. The chemical compositions of 13 groups of obsidian sources in the Kirigamine area were determined by WDXRF and LA–ICP–MS analyses, and discrimination diagrams proposed. For verification purposes, provenance analyses of obsidian artefacts excavated at the Hiroppara prehistoric site were undertaken using these discrimination diagrams. We yielded the same results of provenance analysis among the WDXRF and LA–ICP–MS methods, and the discrimination methods described may be applied to further provenance analysis of obsidian artefacts using nondestructive EDXRF and pXRF, and micro-destructive LA–ICP–MS analyses.

Genetic characteristics and phylogeography of the habitat generalist mayfly Ecdyonurus yoshidae (Ephemeroptera: Heptageniidae) in the Japanese archipelago

AbstractBecause of their early divergence in insect evolution, unique aquatic larval stage, and low dispersal ability, many mayfly species exhibit genetic structures that accurately reflect geological history and paleoclimatic changes. The present study investigated the genetic characteristics of Ecdyonurus yoshidae Takahashi (Ephemeroptera: Heptageniidae), a mayfly that inhabits a variety of freshwater habitats in Japan. Mitochondrial cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (16S rRNA) gene sequences were generated from 209 mayfly specimens that were collected from 109 sites in Japan. A total of 145 haplotypes were detected, and nine of the lineages exhibited geographical regionality, with one lineage being endemic to Lake Biwa. The haplotype network was “bottleneck type” and included both star‐like structures and missing (or unobserved) haplotypes. Together, the haplotype network and FST values indicated that the Fukuejima Island group (Clade I) was genetically distinct from groups on the island of Kyushu, which is separated from Fukuejima Island by the Gotonada Sea. The common ancestor of E. yoshidae lineages in Japan was estimated to have diverged 1.14 mega‐annum (Ma) (95% highest posterior density interval, 0.55–1.78 Ma), and more regional genetic diversities were generated during the Middle to Late Pleistocene. Genetically distinct lineages of eastern and western Japan were separated by the Kinki Triangle region in central Japan. The genetic diversity of the habitat generalist E. yoshidae increased during the Middle and Late Pleistocene, when crustal movement and climate change in the Japanese archipelago occurred simultaneously.

First report of seedling damping off in forage ryegrass caused by Pythium aphanidermatum and P. periilum in Japan.

Italian ryegrass (Lolium multiflorum Lam.) and perennial ryegrass (L. perenne L.) are important for hay fields and grazing lands across Japan, with nearly 70,000 ha production, the largest share in forage grass cultivation. In August 2018, damping off of seedlings of both species was observed about 2wk after seeding in Tochigi Prefecture, central region of Japan. Roots were brown and decayed drastically with browning of basal stem. Nearly 90% of the row seedling stands were eradicated in some fields, especially ones seeded from August to early September, when the soil and air temperatures were around 25-30 ˚C. Six Pythium-like isolates were obtained by isolation from surface-sterilized diseased hypocotyls (1-2cm) placed on water agar. Six isolates were purified as single hyphal tips and deposited at the NARO genebank (https://www.gene.affrc.go.jp/index_en.php), with accession no. MAFF101946-101951. Two of them, MAFF101946 and 101948 were used for detailed study. The isolates were grown in the dark on clarified V8 juice agar for 10 days to produce oogonia. The oogonia of MAFF101946 were globose, colorless, smooth, 21 to 30 µm in size, and had 1(- 2) antheridia. Oospores were mostly aplerotic, and oogonia walls were 1.1 to 2.3 µm thick. The oogonia of MAFF101948 were globose, colorless, smooth, 19 to 27 µm in size, and had 2-5 antheridia. Oospores were mostly plerotic, and oogonia walls were 1.7 to 4.2 µm thick. The morphology of the MAFF101946 matched that of P. aphanidermatum (Edson) Fitzp.(abbr. PA) and the MAFF101948 matched P. periilum Drechsler (abbr. PP) (Van der Plaats-Niterink, 1981). DNA sequences of cox1 (Robideau et al, 2011) and rDNA-ITS regions (White et al,1990) of each isolate were analyzed. The cox1 sequences of the MAFF101946 and 101948 (GenBank Accession No. LC548774 and LC548775) matched 100% (680/680 bp) with that of PA (HQ708486) and PP (HQ708781), respectively. The rDNA-ITS sequence of the MAFF101946, LC592700, matched PA (772/777 bp; HQ643439), and the MAFF101948 (LC592701) matched PP (HQ643740), with 99% similarity (764/773 bp). The optimal growth temperature was 35 ˚C for both. Their pathogenicity was confirmed by seeding two Italian (cv. Inazuma and Minamiaoba) and perennial (cv. Yatsuyutaka and Natsugoshi-pere) ryegrasses cultivars in cell trays containing commercial potting mixture inoculated with the isolates. Barley grains autoclaved with a half volume of water and incubated with each isolate at 25 ˚C for about 2 wk were added to inoculate the potting mixture (5%, v/v). Separate trays were used for each isolate to avoid cross-contamination, sown with 60 seeds were sown per cv. and the trays were placed in a light thermostat chamber under the daily cycle of 16 hr light at 30 ˚C and 8 hr dark at 25 ˚C. About 3 wk later, seedlings on the inoculated soil exhibited the symptoms, but not in control (no inoculum) plots. Both inoculated organisms were re-isolated from the diseased plants to confirm their pathogenicity. PA was more aggressive with grater percent damping off compared to PP. Both species are known as pathogens of diverse plants including grasses and legumes (Abad et al, 1994; Ao et al, 2018), but to our knowledge, this is the first report of seedling damping off caused by these Pythium species in forage ryegrass in Japan. With the increased duration of hot, humid condition across temperate regions due to global warming, the damping off may become a problem in hay fields and pasture and resistance breeding for these pathogens may be needed.

Geographic changes in pollinator species composition affect the corolla tube length of self‐heal (Prunella vulgaris L.): Evidence from three elevational gradients

AbstractGeographic difference in pollinator fauna and variation in average pollinator size may lead to local adaptations of flower size that enhance pollen transfer efficiency. Here, we show that flower size (corolla tube length) of Prunella vulgaris varies both laterally and along elevational gradients, in parallel with local pollinator proboscis length. We measured geographic variation in corolla tube length and leaf length of P. vulgaris, and in proboscis length of its bumblebee pollinators, in 12 populations on three different mountains. In estimating pollinator proboscis length, we considered both the average proboscis length of each bumblebee species and the species composition of bumblebees visiting P. vulgaris flowers. We then ascertained whether pollinator proboscis length, elevation itself, or resource availability (indicated by leaf length) correlated with corolla tube length. We found that the local pollinator species composition varied along elevation and among mountain areas, and this variation corresponded to geographic variation in the average pollinator proboscis length. Similarly, corolla tube length of P. vulgaris varied along elevation and among mountain areas. We found that the corolla tube length variation was not associated with elevation itself or local resource availability but was strongly associated with local pollinator average proboscis length. Although corolla tube length was generally shorter at higher elevation, it was relatively longer in some high‐elevation populations, where bumblebees having long proboscis length (Bombus consobrinus and B. diversus) visited the flowers. Therefore, parallel changes in P. vulgaris corolla tube length and pollinator proboscis length occur across a wide geographic region in central Japan.

Effects of xylem embolism on the winter survival of Abies veitchii shoots in an upper subalpine region of central Japan

At high elevations, winter climatic conditions frequently cause excessive drought stress, which can induce embolism in conifer trees. We investigated the formation and repair of winter embolism in subalpine fir (Abies veitchii) growing near the timberline. We found a complete loss in xylem conductivity [100% percent loss of conductivity (PLC)] at the wind-exposed site (W+) and 40% PLC at the wind-protected site (W−). A PLC of 100% was far above the embolism rate expected from the drought-induced vulnerability analysis in the laboratory. At the W+ site, a PLC of 100% was maintained until May; this suddenly decreased to a negligible value in June, whereas the recovery at the W− site started in late winter and proceeded stepwise. The contrast between the two sites may have occurred because of the different underlying mechanisms of winter embolism. If most tracheids in the xylem of 100% PLC are air-filled, it will be difficult to refill quickly. However, embolism caused by pit aspiration could be restored rapidly, because aspirated pits isolate tracheids from each other and prevent the spread of cavitation. Although severe embolism may cause frost damage of needles, it may have a role in holding water within the stem.

Third Epidemiological Analysis of Nasopharyngeal Carcinoma in the Central Region of Japan from 2006 to 2015.

The present study aimed to clarify the incidence and clinical outcomes of nasopharyngeal carcinoma (NPC) in the Chubu region of Japan from 2006 to 2015, compared with previous reports. A retrospective analysis was conducted based on medical records from 40 hospitals located in the Chubu region in the central Japanese main island, with a population of around 22.66 million individuals. This study was designed in line with to two previous clinical studies into NPC conducted in the same area of Japan. We recruited NPC patients diagnosed in hospitals across this area over a 10-year period (2006–2015) using a questionnaire about sex, age, primary site, clinical symptoms, pathology, Union for International Cancer Control (UICC) staging, serological exam, treatment, and survival. A total of 620 NPC patients were identified. The age-standardized incidence of NPC from 2006 to 2015 was 0.27 per 100,000 individuals per year. There were no significant differences between this study and the previous two studies conducted in the same area of Japan. The five-year overall survival rate for all patients was 75.9%, while those for patients with stages I, II, III, and IVA were 97%, 91%, 79%, and 68%, respectively. The age-standardized annual incidence of NPC in the present study was 0.27 per 100,000 individuals per year, which was relatively low and stable. The five-year overall survival rate for all NPC patients was significantly improved in this decade compared with previous studies. The smoking rates in male and female NPC patients were 64.5% and 18.8%, respectively, thereby suggesting the involvement of smoking in the incidence of NPC.

Estimate of the contraction rate of central Japan through the deformation of the Philippine Sea slab

The Philippine Sea (PHS) slab is severely deformed beneath central Japan, but it is subject to little deformation before the subduction along the Nankai Trough. Thus, it is considered that the currently observed deformation of the PHS slab has been formed only after the subduction along the Nankai Trough. This study estimates the contraction rate of the PHS slab along segments roughly parallel to the Nankai Trough, assuming that the configuration of the PHS slab is stationary in time in the coordinate system fixed to the overriding plate. Results show that the contraction rate is small beneath most parts of Shikoku (≤ 0.3 mm/year) and the offshore fore-arc (≤ 0.6 mm/year), while it increases from the Pacific coastal region (3–6 mm/year) to the inland region (approximately 20 mm/year) beneath central Japan. Considering various error sources, the strain rate is estimated to be about 4–7 × 10−8/year beneath the inland region of central Japan, although it could be reduced by about 20% if the PHS slab has a tear beneath the Kii Strait. Due to the geographical concordance of the deformation between the PHS slab and the upper crust above the slab, the contraction rate of the PHS slab could be used as a proxy to provide an independent estimate of the crustal deformation rate of central Japan over the long term, which is slower than the geodetic estimate while faster than the geologic one.ᅟ

Three pairs of six sporadic acute hepatitis E cases infected with three different genotype 3b hepatitis E virus strains occurred within the same economic bloc in the central region of Japan

Three pairs of six sporadic acute hepatitis E cases infected with three different genotype 3b hepatitis E virus strains occurred within the same economic bloc in the central region of Japan

Changes in vegetation, climate and snowfall regime since the late Pleistocene in a snowy mountainous region of central Japan

Although the most crucial factor shaping vegetation history is temperature, snowfall regime is also important in regions of heavy snow. Pollen analysis in a mire in a snowy mountainous region of central Japan revealed histories of vegetation and precipitation regimes since the latest Pleistocene. The abundance of pinaceous pollen during the latest Pleistocene indicates a subalpine regional coniferous forest and cooler conditions; moreover, sandy sediment and significant occurrence of pollen from Artemisia along with several alpine elements suggest local plant communities of poor vegetation cover in an erosive environment. The increase in Betula and Quercus subgen. Lepidobalanus pollen and the decline in pinaceous pollen in 13,550 cal. yr BP indicates climatic amelioration favourable to temperate trees, and the invasion of sedges and Reynoutria to the small basin and the onset of peat deposition suggest an increase in summer rain. The increase in Fagus crenata pollen after 11,130 cal. yr BP and onwards indicates that the present heavy snowfall regime induced by inflow of the Tsushima Current has been established since that age. The climatic amelioration delayed establishment of the heavy snowfall regime for more than 2400 years. In addition, the retreat of sedges and subsequent invasion of several species of drier habitat after 11,130 cal. yr BP indicate a drier mire condition caused by increased summer temperatures. The recovery of sedges after 3740 cal. yr BP indicates the wettest mire conditions induced by climatic deterioration. A general increasing tendency of conifers in this period supports this interpretation.

Analysis of Pyelonephritis-Associated Beta Hemolytic Streptococcus in Japan

Pyelonephritis is an inflammation of the kidney tissue, calyces, and renal pelvis. It is commonly caused by bacterial infection that has spread up the urinary tract. Common bacteria are Escherichia coli and Enterococcus faecalis. Beta hemolytic streptococci also cause pyelonephritis. Beta hemolytic streptococcus such as Streptococcus agalactiae, and S. dysgalactiae subsp. equisimilis, when grown on blood-agar, produce complete hemolysis around each colony, usually cause severe infections including many cases of cellulitis, pneumonia, meningitis and sepsis. However the analysis of pyelonephritis causing beta hemolytic streptococcus has seldom been investigated. In this study, we tried to clarify the relationship between beta hemolytic streptococcus and pyelonephritis patient in Japan. We investigated beta hemolytic streptococcus isolated from pyelonephritis patient at two tertiary care hospitals in the central region of Japan by analyzing the background and antimicrobial susceptibility of beta hemolytic streptococcus. We recovered total sixteen beta hemolytic streptococcus in nine years. In pyelonephritis patients, beta hemolytic streptococcus was isolated from 9 S. agalactiae and 7 S. dysgalactiae subsp. equisimilis, respectively. The numbers of streptococci from female patients were more than those from male patients. Bacteria were not isolated from under 30 year patients. All S. dysgalactiae subsp. equisimilis were isolated from 60-year-age patients. About one fifth of beta hemolytic streptococcus had erythromycin and minocycline-resistant ability. Four beta hemolytic streptococci that were all S. agalactiae, had levofloxacin-resistant ability. Only one S. agalactiae had trimethoprim-sulfamethoxazole-resistant ability. Ampicillin was effective against all beta hemolytic streptococci. In our results, beta hemolytic streptococcus caused pyelonephritis in aged people and the quarter of these bacteria had some antibiotics resistance.