During June and September, 1965, 14 agents were recovered from blood samples of swine collected in Gumma Prefecture.
Thirteen of the isolates were Japanese encephalitis virus, and one strain (JaGAn 18565) was identified as group A arbovirus.
This virus was referred to as virus because it was isolated from swine at area.
virus shared a common antigen with group A arbovirus and it was closely related antigenically to Getah virus recovered from mosquitoes in Malaya.
Sucrose-acetone extraction of infected suckling mouse brains with virus yielded hemagglutinins and antigens additionally treated with protamine sulfate were more potent than untreated antigens. virus produced the most potent hemagglutinin than any Getah complex viruses.

抄録全体を表示

An easy and useful back-extraction method for measuring copper (II) complexing capacity (CuCC) was established (AKAIWA et al, 1986; AKAIWA et al., in contribution), was used to study the CuCC of Lake water. Using the ultrafiltration technique, it was found that dissolved organic materials having high CuCC were distributed in less than the 10, 000 molecular weight range, and CuCC/DOC (Dissolved Organic Carbon) was the highest in the 1, 000-10, 000 molecular weight range. The CuCC/DOC of Lake water was 0.06-0.08, which was almost similar to the values of other lakes previously reported.
As far as the relation between the molecular weight distribution and the CuCC value, similar tendencies were observed for metabolic products in the growth of Chlorella sp. This consistency might indicate that the algal products are very important in evaluating the CuCC of such as Lake into which artificial pollutants do not flow.
A positive relationship was observed between E₂₆₀ (absorbance at 260 nm) and CuCC in both Lake waters and Chlorella sp. experiment.

抄録全体を表示

Two kinds of pumices and many sorts of decomposed pumices are found in the west-northern part of Kwanto district. One of the not decomposed pumices is an erupted material from Mt. Asama and the other is from Futatsudake in Mt. . Many kinds of decomposed pumices, probably from Mt. Asama are found in the vicinity of Mt. ; and other kinds from Mt.Asama, Mt. and Mt.Akagi are also found at the foot of Mt. Akagi. Socalled "Kanuma Soil''seems to be an erupted material from Mt.Akagi and "Imaichi Soil" is an eruption from Mt.Nantai. From the mineralogical view point, above pumice-soil seems to be roughly classified as follows;[table]

抄録全体を表示

The study on the freezing-out phenomena of lake water is carried out in two mountain lakes, Lake Suwa and Lake in the central part of Japan. The reduction rates were measured concerning the following components : dissolved oxygen, carbon dioxide, ions (Cl, Na, Mg, and Ca), dissolved organic carbon, particulate organic carbon and nitrogen, and bacterial number. Substances in solution in the waters freeze out to 80%. The freezing-out of dissolved oxygen and carbon dioxide was also observed. This may account for the significant accumulation of dissolved gases immediately under the ice at the distinct inverse stratification in Lake Suwa. This accumulation was not observed at a volcanic lake of . In Lake Suwa a trend of the decrease of concentration was observed in the ice from its upper layer to the bottom. In Lake the opposite tendency was observed. The viable number of bacteria reduces by factor 10³ or more in freezing.

抄録全体を表示

volcano, situated in the central part of Japan, erupted twice in the 6th century, from Futatsu-dake crater. The first eruption, which occurred in the early part of the 6th century, was set set off by a low-temperature phreatomagmatic eruption. The initially ejected very fine ash accumulated as accretionary lapilli and muddy rainfalls. Later, the eruption changed to hot pyroclastic flow effusions, which contained many essential lithics. These pyroclastic flow effusions included small-scale phreatic eruptions. The ash had formed ash clouds that then accumulated on each pyroclastic flow deposit. This tephra sequence was named the -Shibukawa tephra formation(Hr-S).
These pyroclastic flow encroached on an older village, Nakasuji, situated on the eastern flank of volcano. The pyroclastic flow (S-5) burned and destroyed many houses. Because its deposit was very thinly laminated, it took the form of a hot pyroclastic surge, which spread over the eastern side of volcano, causing widespread damage there before changing to mud flows and floods and damaging rice fields in the area.
The second eruption, which occurred in the middle or later part of the 6th century, is characterized by plinian eruptions and pyroclastic flow effusions. This tephra sequence was named the -lkaho tephra formation (Hr-I). The pumice ejected in the plinian eruptions was deposited, in a layer about 3cm thick, on Soma city, 200km from the vent.
An older village, Kuroimine, situated about 10km from the vent, was buried by a layer of pumice about 200cm thick. Because pumice oxidized by the flames of burning houses is observed from the bottom to near the top of the pumice fall deposit, we can confirm that the greater part of the pumice accumulated during a period of hours. A house was crushed by the coarser part of the pumice fall deposit (1-6). The pyroclastic flows, which caused columns to collapse, moved and accumulated along the valleys before changing into mud flows and floods. They also caused heavy damage to rice fields and farms.
In Gunma Prefecture, it may well be that villages, rice fields, and farms damaged by volcanic eruptions in the same way as Nakasuji village and Kuroimine village were damaged will be discovered. The data in relation to past volcanic hazards, obtained by joint research between archaeology and volcanology, will contribute to predicting volcanic disasters.

抄録全体を表示

　新期榛名火山の主要な3回の火砕噴火の噴出物について，炭素14年代値が得られたので報告する．得られた年代値は白川火砕流堆積物から2件，二ッ岳渋川テフラから3件，二ッ岳伊香保テフラから4件である．白川火砕流から得られた年代値は45 ka であり，これは新期榛名火山最初で最大の火砕噴火の年代を示す．二ッ岳渋川テフラから得られた年代値は1540～1640 yr BP であり，また二ッ岳伊香保テフラからはいずれも1480 yr BP の年代値が得られた．これらの結果は，二ッ岳渋川噴火は5世紀末～6世紀初頭にかけて，伊香保噴火は6世紀後半から7世紀初頭にかけて発生したことを示す．

抄録全体を表示

Besides the dacitic pumice of Mt. , an igneous rock having the tendency of self-reversal of thermo-remanent magnetization has been found in a pitchstone of Mt. Asio. Although the self-reversal property of the Asio ferromagnetic minerals is weaker than that of the ferromagnetic minerals, the magnetic and crystallographic properties of the former are fundamentally same as those of the latter.
By thermo-magnetic separation, an ensemble of ferromagnetic grains in both the and the Asio rocks were divided into A, B and AB groups. The results of thermo-magnetic measurement, chemical analysis, and X-ray analysis of these three groups showed that the A-constituent is a titanomagnetite of the crystal structure of inverse spinel type having the Curie-point at 430°-510°C, and the B-constituent is an ilmenite-hematite solid-solution of the rhombohedral crystal structure having the Curie-point at about 230°C, while the AB grains are composed of both A- and the B-constituents.
The measurement of thermo-remanent magnetization of a large number of single grain gave the result that only the AB grains can have the reverse thermo-remanent magnetization, the A- and the B- grains getting the ordinary normal thermo-remanent magnetization.

抄録全体を表示

In order to reconsider the mechanism of the self-reversal of TRM (SRTRM) of hemoilmenite in dacite pumice, magnetic properties of newly collected dacite pumice near the historical sampling site (more than 50 years ago) were investigated again. All dacite pumice samples collected showed SRTRM or at least partial SRTRM. This time, the methods of microprobe analysis and the Bitter technique which were not available 50 years ago, were added to examine hemoilmenite crystals. Contrary to the result which was first reported by Hoffmann and Fehr on the basis of the micromagnetic observation of hemoilmenite crystals in Pinatubo dacite pumice, our hemoilmenite crystals are considerably more homogeneous in TiO₂-content in a single crystal than those of Hoffmann and Fehr. Also, we could not find any “shell structure” with two phases having different magnetism and compositions in a single crystal of hemoilmenite in dacite pumice. We came to the conclusion that the intergrown shell-structure itself in Hoffmann and Fehr's model may not be essential but only the coexistence of the intergrown two phases in a single crystal of hemoilmenite must be essential for the acquisition of SRTRM of hemoilmenite. Both models, one by Ishikawa and Syono and the other by Hoffmann and Fehr are basically similar to each other, regardless of the structure involved.

抄録全体を表示

Cultivated barley (Hordeum vulgare L.) is well known as one of the most widely cultivated crops in the world and as an extensively studied plant species in the field of genetics. In recent years, despite its very large genome size (ca. 5,000 Mb), the research resources needed for barley genomic studies have become available, including a large number of expressed sequence tags (ESTs). These have been widely used for barley genome analyses, such as DNA marker-generation and the construction of microarrays. However, the availability of a large-insert genomic library, which is also essential for genomic studies, has been relatively limited in the barley research community. We described here the construction and characterization of a barley bacterial artificial chromosome (BAC) library, using the Japanese malting barley variety ‘ Nijo’. The BAC library consisted of 294,912 clones arrayed in 768 384-well microtiter plates. The average size of each cloned insert was estimated to be 115.2 kb, with approximately 0.5% of the clones lacking inserts. Chroloplast DNAs were present in about 1.7% of the library. Thus, the genomic coverage of the ‘ Nijo’ BAC library was estimated to be about 6.6 genome-equivalents. In order to rapidly identify specific BAC clones, we developed a screening strategy that combined PCR analysis of pooled BAC DNAs with colony hybridization. Using this screening scheme, we investigated the genomic coverage of this BAC library, using 13 locus-specific ESTs and a sequence-tagged site marker. By screening the whole library with individual markers, we identified an average of 5.1 clones per marker. This screening scheme also enabled us to rapidly construct a physical contig spanning a region of approx. 190 kb around the HvBRI1 locus, where the mutation responsible for the semi-dwarf plant type ‘uzu’ is located. These results indicate that the ‘ Nijo’ BAC library will be useful for barley genomic studies.

抄録全体を表示

Polymerase chain reaction (PCR) amplification of mRNA from developing barley (cultivar two-rows) endosperm was used to clone and sequence full-length cDNA encoding, β-amylase. The, β-amylase cDNA was 1, 775 by in length. The β-amylase was deduced to be composed of 535 amino acid residues and its molecular weight was calculated to be 59, 610. Kreis et al. reported that the β-amylase cDNA from barley (cultivar Hiproly) was 1, 754 bP in length and coded for a polypeptide of 535 amino acids [Eur. J. Biochem. (1987) 169, 517-525]. A comparison of the β-amylase sequences from two-rows and Hiproly barleys revealed nine differences in the nucleotide sequence which resulted in three changes in the amino acid residues and 21 additional nucleotides at its 3'-end in the cultivar two-rows. The three changes were as follows: Ala-233, Ser-347, Met-527 ( two-rows) and Val-233, Met-347, Ile-527 (Hiproly). Lundgard and Svensson pointed out that 23 amino acid residues of the peptide fragment derived from the COOH-terminal region of barley (cultivar Gula) β-amylase were in agreement with the deduced amino acid sequence reported by Kreis et al., with the exception of a single position (Met-527 compared to Ile) [ Carlsberg Res. Commun. (1986) 51, 487-491]. Our findings described above showed Met-527 is reasonable. In the cases of β-amylases from soybean and sweet potato, the positions that corresponded to those at 233 and 347 in the amino acid sequence of β-amylase from barley were Ala and Ser, respectively. Therefore, Ala-233 and Ser-347 in the amino acid sequence of barley .β-amylase were thought to be reasonable. Sequence homology of barley β-amylase with the enzymes from soybean and sweet potato amounted to 66.7 and 59.2%, respectively.

抄録全体を表示

Sum of eleven tephras occur in Mount Tairappyo (36° 48' N, 138° 49' E, 1, 984 m asl) ofthe Mikuni Mountains, central Honshu Island, Japan. Although these tephras are thought to be useful for Quaternary studies in this area, they have not been described systematically. We investigated stratigraphy, lithofacies, petrographic properties, and refractive indices of volcanic glass shards and phenocrysts of these tephras in order to correlate them with the known ones. We also estimated the calendric ages of the tephras based on their stratigraphy and the radiocarbon ages in the previous references.
The followings were identified :
1) the

Haruna

-Futatsudake-Ikaho as 1.44 ka, 2) the

Haruna

-Futatsudake-Shibukawa as 1.47 ka,
3) the Myoko-Otagirigawa as 4.7 ka, 4) the Asama-Tairappyosan 1 as 4.9 ka, 5) the Asama-Tairappyosan 2 as 6.3 ka, 6 and 7) the Myoko-Akakura and the Asama-Tairappyosan 3 as 6.6 ka, 8) the Asama-Tairappyosan 4 as 6.8 ka, 9) the Kikai-Akahoya as 7.2 ka, 10) the Asama-Tairappyosan 5 as 7.5 ka, and 11) the Asama-Kusatsu as 16 ka.
Among them, the Myoko-Akakura and the Asama-Tairappyosan 3 are very unique. The former overlies the latter without intercalation of soil layers, and these two tephras form a thin layer. A set of the two can be correlated with the tephra X found from the Ozegahara bog about 60 km east of Tairappyo. Depositional conditions of these tephras imply that the eruption of Myoko volcano followed that of Asama without long interval, possibly less than few years, in the mid Holocene. A thin layer composed of the Myoko-Akakura and the Asama-Tairappyosan 3 is important as a key bed, as well as the

Haruna

-Futatsudake-Ikaho, the Kikai-Akahoya, and the Asama-Kusatsu all of which have been described as wide spread tephras. All the tephras provide Quaternary studies in this area with datum planes.

抄録全体を表示

One strain of vitamin B_6 synthesizing bacterium, which was isolated by Suzue and from soil, was bacteriologically studied, and it is considered that it belongs either to Aerobacter aerogenes or to Klebsiella pneumoniae.

抄録全体を表示

The detailed mechanism of the self-reversal of thermo-remanent magnetism of rocks was studied. The ferromagnetic mineral grains responsible for this phenomenon were determined as A′B-grains, which consist of two constituents, A′ and B. The magnetic and crystallographic examinations of rocks showed that the constituent with higher Curie point, in the two-constituent model, should be estimated to be a solid solution between ilmenite and hematite, and not the Ti-poor titanomagnetite as was estimated to be in the previous studies. In other words, the magnetic interaction causing the self-reversal of thermo-remanent magnetism is between two ilmenite-hematite solid solutions with different Curie points. Electron-microscopic observations showed that the constituent with higher Curie point is intergrown into the constituent with lower Curie point as fine lamellae. The observed configurations of these two constituents indicated that the phenomenon of reverse thermo-remanent magnetism could be explained theoretically, provided that the grains as fine as the observed lamellae have very strong thermo-remanence.
Similar examinations were conducted on ferromagnetic minerals of several other rocks with the same mineral assemblage as the ferromagnetic minerals. The results of these examinations indicated that there exist, in natural ferromagnetic minerals, various degrees of magnetic interaction which are governed by their state of co-existence.

抄録全体を表示

We have studied four lava dome eruptions which occurred in 45–10 ka in

volcano. Enclave parts (SiO₂ 50.9–55.1 wt%) and host parts (SiO₂ 59.5–64.5 wt%) in lava samples are all products of magma mixing. Characteristics of felsic endmember magmas are the same among four eruptions, while those of mafic endmember magmas vary slightly in terms of bulk composition. The felsic magma had SiO₂ ≥ 63 wt% and a temperature of 760°C–860°C, and contained ≥60 vol% of orthopyroxene, amphibole, plagioclase, quartz, and Fe-Ti oxides. The mafic magma had SiO₂ 48–51 wt% and contained 0–10 vol% of olivine. The enclave magmas resulted from higher contribution of mafic magma and thus had higher temperature than the host magmas, which led to formation of enclave upon their interaction. Similarities of endmember magmas between the four eruptions and the Futatsudake-Ikaho eruption (late 6th–beginning of 7th century) suggest structure of magma plumbing system and eruption triggering process have been basically unchanged in past 45,000 years. The felsic magmas were commonly mush-like and had high viscosity. Therefore, generation of low-viscosity magma through magma mixing, and vent-opening by the low-viscosity magma are mandatory for eruption to initiate. Unlike the Futatsudake-Ikaho eruption, the older four eruptions did not proceed to eruptive phase where felsic magma erupts without mixing and explosively. The absence of quartz only in felsic magma of Futatsudake-Ikaho eruption is consistent with its less-evolved bulk composition and slightly higher temperature than those of older four eruptions.

抄録全体を表示

The summer phytoplankton of Lake in 1948 was characterized by an enormous appearance of Anabaena planktonica bloom. The eutrophication of this lake increased remarkably since 1927, declined during a period of 1934-1936, and has risen again in recent years.

抄録全体を表示

The absorption coefficient of particulate matter at wave length λ, a_p (λ), is expressed by the sum of the absorption coefficients of detritus a_d (λ) and phytoplankton a_pl (λ), and a_pl (λ) is given by the product of the specific absorption coefficient of chlorophyll-a p_ph (λ) and chlorophyll-a concentration at depth z, C (z).
The value of a_ph (λ) in the region 400700 nm is maximum at λ=440 nm, so in Lake a_p (440) and C (z) were measured, and a_d (440) and a_pl (440) were obtained. The value of a_p (440) at z=12 m except that on 16 November was much larger than at z=0, 4, and 8 m. This may be caused by turbulence which may be effected by bottom current.
When the lake water is divided into some layers, let a_p (440) _i and Δz_i be the value of a_p (440) and thickness of the i-th layer and let z_n be the depth of the lower plane of the n-th layer. For the same solar altitude, absorptance by particulate matter in the lake water between z=0 and z_n, A_p (440) _zn, increases as the value of ⁿΣ_i=1a_p (440) _iΔz_i increases. Accordingly, the value of ⁿΣ_i=1a_p (440) _iΔz_ii each month was calculated and compared instead of the value of A_p (440) _zn. Similarly, values of ⁿΣ_i=1a_d (440) _iΔz_ii and ⁿΣ_i=1a_pl (440) _iΔz_ii were calculated and compared. a_d (440) i and a_pl (440) i are the values of a_d (440) and a_pl (440) of the i-th layer.

抄録全体を表示

Focusing to the self-reversal of Thermo-Remanent Magnetization (TRM), we examined magnetic properties of 32 pieces of unoriented pumice samples, which were systematically collected from eight layers of pumice-fall and pumice-flow deposits at Volcano, Japan in the two stages of the eruption, i. e., Futatsu-dake stage (the 5th stage) and caldera-forming stage (the 4th stage). The magnetic behaviors of TRM well correlated with the primary chemical composition (TiO₂-content or x (molecular fraction value of ilmenite in xFeTiO₃- (1-x) Fe₂O₃) ) of the hemoilmenite phenocrysts in the samples. That is, the samples of which chemical composition of hemoilmenite is TiO₂ - 30 wt% (x - 0.582) showed various types of TRM including typical intense Self-Reversed Thermo-Remanent Magnetization (SRTRM), whereas the samples of which chemical composition of hemoilmenite is TiO₂ - 32 wt% (x - 0.620) showed one type of TRM; weak intensity of self-reversed component of TRM. This result harmonizes with the well-known diagram by Uyeda, where the intensity of SRTRM of hemoilmenite (quenched) is an explicit function of the chemical composition, and only in the restricted narrow range of the chemical composition, intense SRTRM is acquired. Moreover, the hemoilmenite samples of which chemical composition is less than TiO₂ - 31 wt% (x - 0.60) are capable to acquire various intensities of SRTRM on annealing according to its condition. In our TiO₂-poorer (or smaller-x) samples, the variety in the behavior of TRM is well explained with this annealing effect in this compositional range.

抄録全体を表示