A negative oxide charge located at the split-point is the main cause of threshold voltage window closure in source side injection flash EEPROM cells under 10/sup 5/ write/erase cycles. We show a slow ...trapping rate and a temperature dependence of the detrapping rate below 100/spl deg/C. The detrapping rate is not temperature dependent between 100/spl deg/C and 250/spl deg/C. Finally, the split-point charge formation can be significantly reduced by using of a ramped write pulse.
Photosynthetic organisms adapt to changes in light quality by redistributing light excitation energy between two photosystems through state transition. This reorganization of antenna systems leads to ...an enhanced photosynthetic yield. Using a genetic approach in Chlamydomonas reinhardtii to dissect the signal transduction pathway of state transition, we identified a chloroplast thylakoid-associated serine-threonine protein kinase, Stt7, that has homologs in land plants. Stt7 is required for the phosphorylation of the major light-harvesting protein (LHCII) and for state transition.
Thin SiO 2 films nitrided by rapid thermal processing in N 2 O and NH 3 are compared. The effect of nitrogen on growth kinetics, composition and electrical characteristics is determined.
Purpose:
The purpose of this study was to look for a new, simple, and fast method of assessing and monitoring indoor race performance and to assess the relationship between 20 s, 60 s, and 2000 m ...indoor rowing performances of youth rowers to evaluate their anaerobic profile.
Methods:
For three consecutive days, 17 young able-bodied male rowers (15.8 ± 2.0 years), performed three tests (20 s, 60 s, and 2000 m) on a rowing ergometer. Mean power (W
20
, W
60
, and W
2000
) and 2000 m time (t
2000
) were considered for the analysis. In addition, 14 athletes (15–18 years) performed a 20 s, 60 s, and 2000 m tests and used this as a control group. To define the anaerobic profile of the athletes, W
20
and W
60
were normalized as percentages of W
2000
. Associations between variables were determined by means of the Pearson correlation coefficient (
r
).
Results
:
Mean power decreased with increasing test duration (W
20
= 525.1 ± 113.7 W; W
60
= 476.1 ± 91.0 W; W
2000=
312.9 ± 56.0 W) and negative correlations emerged between t
2000
(418.5 ± 23.1 s) and W
20
(
r
= −0.952,
p
< 0.0001) and W
60
(
r
= −0.930,
p
< 0.0001).
Conclusion:
These findings indicate that W
20
and W
60
are significant predictors of 2000 m rowing ergometer performances. Furthermore, normalized W
20
and W
60
can be used to evaluate athletes and as a reference for planning anaerobic training sessions, on a rowing ergometer.
Summary
The rice root-knot nematode, Meloidogyne graminicola, is a serious pathogen of rice production worldwide. In Vietnam, scientific information on the rice root-knot nematode is limited. In this ...circumstance, our study aimed to investigate the characteristics of M. graminicola from rice fields in southern Vietnam and to evaluate the reaction of 20 rice varieties to this soil-borne pathogen in a glasshouse experiment. Ten populations of root-knot nematode collected from rice fields at different geographical regions in the Mekong Delta were identified as M. graminicola based on the perineal configuration of females and species-specific molecular markers. The morphological, morphometric and molecular characteristics of ten nematode isolates were defined, and the variations observed between these isolates were not significantly different. The pathogenicity of these isolates was examined in the susceptible Indica rice, Oryza sativa ‘IR64’, with a reproduction factor ranging from 18.1 to 37.8. Of the 20 Indica rice varieties tested in response to the nematode population MG-PN08, the ‘Tetep’ variety showed moderate resistance to the nematode (reproductive factor = 11.7; galling index = 2.4), while others were ranked at levels ranging from moderately susceptible to highly susceptible. The life cycle of M. graminicola in ‘Tetep’ root is 28 days compared to 21 in ‘IR64’. ‘Tetep’-nematode interaction at the histological and molecular levels needs further investigation to develop new rice varieties resistant to rice root-knot nematode.
Summary
The root-knot nematodes (RKN) Meloidogyne graminicola and M. incognita are responsible for rice yield losses worldwide, particularly in Asia and Africa. Previous studies demonstrated that ...nematode-secreted proteins are crucial for root invasion and establishment in the host. We present some characteristics of a pioneer effector, M. incognita-secreted protein 4 (Mi-SP4), which is conserved in RKN and required for infection in compatible rice-RKN interactions. In situ hybridisation assays revealed Mi-SP4 expression in the dorsal pharyngeal gland of M. incognita second-stage juveniles (J2). Meloidogyne-SP4 transcripts strongly accumulated in pre-parasitic J2 and decreased in later parasitic stages of M. incognita and M. graminicola. Transient expression of the nematode effector gene in Nicotiana benthamiana leaves and onion cells indicated that GFP-tagged Mi-SP4 was present in the cytoplasm and accumulated in the nucleus of the plant cells. In vitro RNA interference (RNAi) gene silencing, obtained by soaking J2 with small-interfering (si)RNA si4-1, decreased Mi -SP4 expression in J2 by 35% and significantly reduced M. incognita reproduction in rice by at least 30%. Similarly, host-mediated gene silencing of the nematode SP4 effector candidate gene in transgenic rice plants significantly reduced M. graminicola reproduction by 26% to 47%. The data obtained demonstrate that Mi -SP4 is a pioneer virulence effector, which plays an essential role in both M. incognita and M. graminicola pathogenicity on rice.
Hsp60, a mitochondrial chaperonin highly conserved during evolution, has been found elevated in the cytosol of cancer cells, both in vivo and in vitro, but its role in determining apoptosis during ...oxidative stress (OS) has not yet been fully elucidated. The aim of the present work was to study the effects of OS on Hsp60 levels and its interactions with procaspase- 3 (p-C3) and p53 in tumor cells. NCI-H292 (mucoepidermoid carcinoma) cells were exposed to various concentrations of hydrogen peroxide (H2O2) for 24 hours. Cell viability was determined by Trypan blue and MTT assays. DNA damage was assessed by the Comet assay, and apoptosis was measured by the AnnexinV cytofluorimetric test. Exposure to increasing concentrations of H2O2 resulted in a reduction of cell viability, DNA damage, and early apoptotic phenomena. Hsp60, p-C3, p53, and p21 were assessed by Western blotting and immunocytochemistry before and after OS. Hsp60 and p-C3 were present before and after OS induction. Immunoprecipitation experiments showed an Hsp60/p-C3 complex before OS that persisted after it, while an Hsp60/p53 complex was not detected in either condition. The presence of wild type (wt) p53 was confirmed by RT-PCR, and p21 detection suggested p53 activation after OS. We postulate that, although OS may induce early apoptosis in NCI-H292 cells, Hsp60 exerts an anti-apoptotic effect in these cells and, by extension, it may do so in other cancer cells.
Plant-parasitic nematodes developed strategies to invade and colonize their host plants, including expression of immune suppressors to overcome host defenses. Meloidogyne graminicola and M. incognita ...are root-knot nematode (RKN) species reported to damage rice (Oryza sativa L.) cultivated in upland and irrigated systems. Despite M. incognita wide host range, study of the molecular plant - RKN interaction has been so far limited to a few dicotyledonous model plants. The aim of this study was to investigate if the rice cv. Nipponbare widely used in rice genomic studies could be used as a suitable monocotyledon host plant for studying M. incognita pathogenicity mechanisms. Here we compared the ability of M. graminicola and M. incognita to develop and reproduce in Nipponbare roots. Next, we tested if RKNs modulates rice immunity-related genes expression in galls during infection and express the Mi-crt gene encoding an immune suppressor. Root galling, mature females, eggs and newly formed J2s nematodes were obtained for both species in rice cultivated in hydroponic culture system after 4-5 weeks. Meloidogyne graminicola reproduced at higher rates than M. incognita on Nipponbare and the timing of infection was shorter. In contrast, the infection characteristics compared by histological analysis were similar for both nematode species. Giant cells formed from 2 days after infection (DAI) with M. graminicola and from 6 DAI with M. incognita. Real-time PCR (qRT-PCR) data indicated that RKNs are able to suppress transcription of immune regulators genes, such as OsEDS1, OsPAD4 and OsWRKY13 in young galls. Four M. incognita reference genes (Mi-eif-3, Mi-GDP-2, Mi-Y45F10D.4, and Mi-actin) were selected for normalizing nematode gene expression studies in planta and in pre-parasitic J2s. Meloidogyne incognita expressed the immune suppressor calreticulin gene (Mi-crt) in rice roots all along its infection cycle. RKNs repress the transcription of key immune regulators in rice, likely in order to lower basal defence in newly-formed galls. The calreticulin Mi-CRT can be one of the immune-modulator effectors secreted by M. incognita in rice root tissues. Together, these data show that rice is a well suited model system to study host- M. incognita molecular interactions in monocotyledons.PUBLICATION ABSTRACT
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