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1.
The glucose uptake activity in Babesia rodhaini and B. microti - infected red blood cell (IRBC) was investigated in mice using 2-deoxy-D-glucose (2DOG) and L-glucose (L-Glc), a non-metabolizable analogue of D-glucose and non-incorporative glucose to non-infected RBC (NRBC), respectively. The uptake activities of both DOG and L-Glc were higher in IRBCs than those in NRBC. The concentration dependent uptake of 2DOG and L-Glc in both IRBC revealed a linear curve, indicating non-transporter mediated uptake. In addition, B. microti IRBC showed higher 2DOG uptake than B. rodhaini IRBC, whereas no difference was observed in L-Glc uptake. These results indicated that some new glucose uptake system, at least two systems, developed in both IRBC. The new systems were sodium independent, non-competitive to L-Glc, and sensitive to temperature. One of two systems had no kinetical difference between B. rodhaini and B. microti IRBC, however another one might have higher uptake activity in B. microti IRBC compared to that in B. rodhaini IRBC.  相似文献   
2.
In this study, we determined the color vision and spectral sensitivity of pointhead flounder, slime flounder, and red halibut by recording electrophysiological S-potentials from isolated retinas; this basic data was collected to aid the selection of appropriate colors and effective wavelengths for selective fishing gear for sustainable fisheries. Four kinds of L-response and one C-response were recorded in the pointhead flounder and red halibut. Two kinds of L-response were recorded in the slime flounder. The occurrence of a C-response indicates the possession of color vision. The C-responses show that the pointhead flounder has superior distinction from blue to yellow, and red halibut has superior distinction from blue and green to red. The most frequently recorded L-responses indicate high spectral sensitivity at 544 nm in pointhead flounder and 518 nm in slime flounder and red halibut. All recorded L- and C-responses indicate sensitivity to ultraviolet wavelengths.  相似文献   
3.
Denitrification is an important part of the nitrogen cycle in the environment, and diverse bacteria, archaea, and fungi are known to have denitrifying ability. Rice paddy field soils have been known to have strong denitrifying activity, but the microbes responsible for denitrification in rice paddy field soils are not well known. Present study analyzed the diversity and quantity of the nitrite reductase genes (nirS and nirK) in a rice paddy field soil, sampled four times in one rice-growing season. Clone library analyses suggested that the denitrifier community composition varied over sampling time. Although many clones were distantly related to the known NirS or NirK, some clones were related to the NirS from Burkholderiales and Rhodocyclales bacteria, and some were related to the NirK from Rhizobiales bacteria. These denitrifiers may play an important role in denitrification in the rice paddy field soil. The quantitative PCR results showed that nirK was more abundant than nirS in all soil samples, but the nirK/nirS ratio decreased after water logging. These results suggest that both diversity and quantity changed over time in the rice paddy field soil, in response to the soil condition.  相似文献   
4.
Symbiotic efficiency and compatibility of 81 isolates of native bradyrhizobia from irrigated areas in northern Thailand with four soybean cultivars and one cowpea cultivar were evaluated under laboratory conditions. Effectiveness and / or compatibility of the tested isolates were compared with those of a standard strain (Bradyrhizobium japonicum CB 1809) by using plants grown on plastic seed bags. Effectiveness of the isolates was also estimated using uninoculated control plants grown in a nitrogen-free solution. Nodulation of a wide range of host plants by the majority of the tested isolates was observed, which agreed well with the results of our previous field experiment (Shutsrirung et al. 2002: Soil Sci. Plant Nutr., 48, 491–499). Up to 75% of the tested isolates induced a higher growth efficiency than that of the uninoculated control in association with one of the tested cultivars, Black soybean. Comparision with uninoculated control plants, enable to estimate the proportion of the tested isolates leading to effective growth promotion (E + e) of each cultivar, namely, Black soybean (local Thai cultivar), 75%; Cowpea, 82%; SJ5 (commercial Thai cultivar), 33%; Bragg (US cultivar), 33%; and Improved Pelican (US cultivar), 9%. These results indicated that although isolates with a high infectiveness with both “Asian-type” and “US-type” soybeans could be found, a high frequency of isolates leading to inefficient nodules was observed in the US cultivar, suggesting the presence of genetic differences in the soybean cultivars that express high-preference (efficient nodules) or low-preference (inefficient nodules) for a certain group of tested isolates. Based on the results of this laboratory experiment together with our previous field experiment, native rhizobial populations in the irrigated area of northern Thailand could be separated into three groups; Group 1: rhizobium strains showing a high effectiveness with only Asian cultivars, Group 2: strains showing a high effectiveness with only US origin cultivars, and Group 3: strains showing a high effectiveness with both Asian and US origin cultivars. The majority of the native rhizobial populations belonged to Group 1. The isolates in Group 3 may display a high potential for manipulating useful rhizobial inoculant.  相似文献   
5.
Various types of mineral particles in a soil probably provide different microenvironments for microorganisms. The purpose of this study is to investigate whether different types of mineral in a soil harbor different bacterial populations. DNA was extracted from five types (quartz, feldspar, pyroxene, magnetite, iron-coated reddish brown particles) of sand-size mineral particles separated from a sandy soil, and was amplified for partial 16 S rRNA gene by polymerase chain reaction (PCR). Twenty-nine to 69 amplicons per each type of mineral were cloned and sequenced, followed by phylogenetic affiliation of the sequences. As a result, some types of bacteria were detected on all of the types of mineral including the orders Rhizobiales, Bacillales, and Acidobacteriales. In the case of Acidobacteriales, higher percentages were found on magnetite and quartz. Some taxa were restricted to specific types of mineral; the class Actinobacteria was found on pyroxene but not on quartz, and rarely on magnetite and feldspar. Bacterial diversity at the order level estimated by Chao1 value was higher in feldspar and pyroxene than the other three types of mineral. The UniFrac Significance test indicated that the differences in bacterial communitiy structures among the particles were suggestive except that between feldspar and pyroxene. These results support the idea that different communities of bacteria were associated with each of the mineral types.  相似文献   
6.
Tumour necrosis factor‐related apoptosis‐inducing ligand (TRAIL) is an apoptosis‐inducing cytokine that shows potential therapeutic value for human neoplasms, and is effective in some canine tumours; however, its potential for killing canine hemangiosarcoma (HSA) cells is unknown. Thus, we evaluated the proapoptotic effect of TRAIL in nine canine HSA cell lines. Cells (JuA1, JuB2, JuB2‐1, JuB4, Re11, Re12, Re21, Ud2 and Ud6) were cultured with three recombinant human TRAILs (rhTRAILs): TRAIL‐TEC derived from Escherichia coli, TRAIL‐TL derived from mammalian cells and isoleucine zipper recombinant human TRAIL (izTRAIL) containing an isoleucine‐zippered structure that facilitates trimerization. TRAIL‐TEC did not decrease the cell viability in any of the cell lines tested, whereas the other two rhTRAILs effectively decreased the viability of all cell lines as assessed by the WST‐1 assay. In canine HSA cells, izTRAIL induced apoptosis more effectively than TRAIL‐TL. In JuB4, Re12, and Ud6 cells, izTRAIL increased the activation of caspase‐3 and caspase‐8 and caused poly (ADP‐ribose) polymerase degradation. Moreover, izTRAIL treatment increased the proportion of Annexin V+/ Propidium iodide (PI)? apoptotic cells and nuclear fragmentation in izTRAIL‐sensitive cells. These results show that rhTRAIL can induce apoptosis in canine HSA cells, but the sensitivity of TRAIL was different depending on the cell lines. Therefore, TRAIL could be an effective therapeutic agent against canine HSA, but the specific mechanism of resistance should be determined to clarify under what conditions this treatment would be most effective.  相似文献   
7.
How nitrogen (N) cycling is regulated and how environmental change affects it are major study questions in forest ecology, because N availability often limits the primary production of plants in many forest ecosystems. These are being extensively highlighted because of growing concerns regarding chronic and elevated N deposition in forest ecosystems on a global scale. Until now, N cycling has been mainly documented in association with various environmental factors other than microbial communities. However, with the recent rapid development in culture-independent molecular-based techniques, microbial ecologists have discovered that alterations in N cycling are highly associated with alternations in microbial communities through changes in either resource supplies or processing rates. In this review, we describe nitrification as a key N cycling process and present general approaches to associate the nitrification process with the nitrifying community in forest soils. Furthermore, we briefly summarize currently available information about the relationship between the process and nitrifying community dynamics in soil. We suppose that linking N cycling processes with microbial community dynamics provides a deeper insight into the mechanisms regulating N cycling in forest ecosystems.  相似文献   
8.
9.
The Rio Grande do Sul state, in Southern Brazil, is one of the foci of human cystic echinococcosis (CE). The sheep strain (G1) of Echinococcus granulosus and Echinococcus ortleppi (also known as cattle strain G5) have been reported before to infect livestock. However, up to the present, no molecular data are available on isolates of the E. granulosus complex from humans and dogs. The present study analyzed hydatid cysts from 6 CE patients and adult worms from 12 dogs. Sequencing of the mitochondrial cox1 and 12S rRNA genes detected the E. granulosus G1 genotype from four human cases, the G3 genotype (or buffalo strain) from one human case and E. ortleppi from another human case, respectively. Ten of the twelve dogs were found infected with the G1 genotype, and one dog each harbored worms of the G3 genotype and E. ortleppi. Obvious morphological differences were recognized between the G1 and E. ortleppi adult worms from dogs in this region. The buffalo strain (G3) is for the first time reported from South America.  相似文献   
10.
Bacterial communities in a spoil heap in a copper mine, a forest soil with high Cu contamination, and an agricultural soil with low Cu contamination were characterized in terms of Gram-staining, plasmid frequency, pigmentation, Cu-resistance system, and predominant Cu-resistant bacterial species. Similarity existed in that the ratio of green colonies for sorbing Cu and Gram-negative bacteria increased with the increase of the Cu content of the medium regardless of the characteristics of the bacterial communities. It was found that the plasmid was not present in most of the Cu-resistant bacteria of the soils. Curesistant genera including Burkholderia, Alcaligenes, and Methylobacterium species were isolated from the Cu contaminated soils using YG agar plates treated with 2 mM Cu. Furthermore, the bacterium with the highest Cu resistance (MIC = 5.5 mm Cu) was identified as a Gram-positive bacterium Bacillus sp., though most of the Cu-resistant bacteria were Gram-negative.  相似文献   
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