Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Replication Timing”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMed2003

[Field efficacy of emulsifiable suspensions of Beauveria bassiana conidia for control of Myzus persicae population on cabbage].

The conidial powder of Beauveria bassiana SG8702 produced using a diphasic fermentation technology was formulated into emulsifiable suspension I (EI-I, > 10(10) conidia.ml-1) and ES-II, which resulted from adding 1% (W/V) of imidacloprid 10% WP to the ES-I. Three dilutions (10(7), 10(6), and 10(5) conidia.ml-1 of each were sprayed onto cabbage plants for control of the green peach aphid Myzus persicae population in field plots in Kunming, Yunnan during July 2001. Each dilution and a water spray as control were replicated three times. During a 28 d period of sampling at 3 or 4 d intervals, spray of the ES-II at 10(7) conidia.ml-1 controlled the increase of the aphid population by > 90% consistently from day 7 after spray. The efficacy for the ES-I at the same concentration reached 85% on day 7 after spray, exceeded 70% in the following two weeks, but declined to 64.4% on day 24 and 52.6% on day 28. At the lower concentrations sprayed, both suspensions significantly suppressed the increase of M. persicae population, but the ES-II resulted in higher efficacy than the ES-I. Local summer weather with mild temperature and frequent rainy days was favorable to the use of the formulations for aphid control.

Animals↗
PubMed2003

Comparison of the effectiveness of baits used in traps for adult fly collection.

The effectiveness of 6 different baits used in fly traps for adult fly collection was compared in October-November, 2000, near the cafeteria of Maharaj Nakhon Chiang Mai Hospital, Chiang Mai Province, northern Thailand. The baits used were fresh viscera (pork, beef and fish) and fresh meat (pork, beef and fish), with 500 g of each kind being used in each fly trap for each experiment. All were replicated four times. Pork viscera yielded the highest effectiveness (35.2%), followed by fish meat (30%). Four other kinds of bait showed relatively low efficiency, ie fish viscera (12.0%), beef viscera (9.0%), pork meat (8.4%) and beef meat (5.4%). The calliphorid Chrysomya megacephala was the most abundant fly species collected, while sarcophagids and muscid flies were found in much smaller numbers. The number of females was higher than males in all collections. Although all baits used were parts of animal carcasses that were very attractive for adult flies to feed upon and oviposit, the result of this study showed the differences in their effectiveness for fly collection, particularly during the late rainy season to early winter in Chiang Mai. Pork viscera showed the highest efficacy for metallic fly collection, but not for all species. Further study of suitable baits for the medically important fly species that exist in urban areas should, therefore, be performed.

Animals↗
PubMed2003

Field response of some asparagus varieties to rust, Fusarium crown root rot, and violet root rot.

Research was carried out to evaluate the behaviour of some asparagus genotypes against three most important fungal diseases: 1) asparagus rust caused by Puccinia asparagi D.C.; 2) Fusarium crown and root rot caused by Fusarium oxysporum (Schlecht.) f.sp. asparagi (Cohen & Heald) and Fusarium proliferatum (Matstush.) Nirenberg; 3) violet root rot caused by Rhizoctonia violacea Tul. The object of this research was also to found an eventual correlation between the plant susceptibility to asparagus rust and the sensibility to Fusarium crown root rot and violet root rot attacks. Resistant genotypes to rust should be less susceptible to attacks from F. oxysporum f.sp. asparagi, F. proliferatum and R. violacea, a fungal complex causing the plant decline. Asparagus genotypes were compared in a randomized complete block experiment design, replicated four times, in order to search that ones showing the best behaviour to escape the diseases. Phytopathological observations were carried out on November when the control plots showed 100% infected plants. The pathogens were isolated and identified. The diseased plants were registered. According to symptom evaluation scales, all the plants were grouped into infection classes, calculating frequency and McKinney index. Wishing to learn something about the infection trend of F. oxysporum f.sp. asparagi or R. violacea in relation to P. asparagi attack, the relative curvilinear regressions were calculated. The Italian cultivars "Marte" and "Grande" showed significantly the best behaviour in terms of resistance to asparagus rust, exhibiting 37% and 42% of diseased plants. The McKinney index was 9.1% and 15.6%, respectively. The susceptible plots showed 100% of infected plants and different McKinney index: 46% for "Eros", about 60% for "H 519", "Atlas" and "Golia", over 70% for the remainder. "Marte" and "Grande" showed good tolerance to F. oxysporum f.sp. asparagi and to R. violacea exhibiting up to 100% of healthy plants. The regression between plants affected by asparagus rust and those diseased by Fusarium crown root rot showed a linear equation with a regression coefficient b = 1.186 and a correlation coefficient R2 = 0.98. The regression between infection caused by rust and that caused by violet root rot exhibited a regression coefficient b = 1.03 and a coefficient of correlation R2 = 0.9. "Marte" and "Grande" exhibited the best behaviour against the rust attacks. Plants without rust were tolerant to pathogens causing plant decline.

Asparagus Plant↗
PubMed2005

[Effects of antithrombin-III on cytokines in rats with multiple organ dysfunction syndrome].

OBJECTIVE: To observe the effect of the antithrombin-III (AT-III) on cytokine levels in multiple organ dysfunction syndrome (MODS) in rats. METHODS: Seventy Wistar rats were randomly divided into three groups: normal control group, MODS group, and AT-III treatment group. The rats in MODS group and the treatment group were given lipopolysaccharide (LPS) two times to replicate systemic inflammatory response syndrome (SIRS)/MODS model. One hour after the injections of LPS, the rats in the treatment group were given AT-III (25 U/kg, 0.5 ml/100 g) intravenously. Four hours after treatment, blood samples were collected in rats. The tissue samples were collected and preserved in formalin. By use of radioimmunoassay and histopathology, the effect of the AT-III was observed in rats with SIRS/MODS. RESULTS: Endotoxin (ET), interleukin-1 (IL-1), IL-6 and tumor necrosis factor-alpha (TNF-alpha) levels were all increased significantly in MODS animals (all P<0.01), and they were decreased after AT-III treatment (all P<0.01), though still higher than those of the normal controls (all P<0.01). The pathologic changes in lung, kidney and liver in the treatment group were milder than in the MODS group. CONCLUSION: These data suggest that AT-III could inhibit systemic inflammatory response and it might be used in the treatment of SIRS/MODS.

Animals↗
PubMed2003

[Evaluation for enhanced aphidicidal activity of a noval emulsifiable formulation of Beauveria bassiana conidia].

A noval emulsifiable formulation (EF) of Beauveria bassiana SG8702 containing 10(10) conidia/mL was prepared by suspending dry conidia in mineral oil-based liquid containing emulsifier, stabilizer and UV protectant (emulsion), and then bioassayed on newly merged adults of the green peach aphid, Myzus percisae, in parallel to the unformulated conidia (UC). For inoculation, five gradient concentrations of aqueous EF and UC suspensions (5 x 10(5) - 1 x 10(8) conidia/mL) were separately sprayed on to aphids on detached cabbage leaves (30 - 40 adults/leaf) using a Micro Ulva hand-held sprayer, generating EF dosages of 1.5, 6.3, 32.6, 87.6 and 701.1 conidia/mm2, and UC dosages of 2.8, 9.2, 52.7, 114.8 and 1005.9 conidia/mm2, respectively. All dosage treatments including controls for EF (100-fold dilution of the emulsion) and UC (water spray) were replicated three times (aphid colonies on three leaves), and maintained in Petri dishes at 23 degrees C and 12 : 12 (L: D) for 8-day daily records. Cadavers, whenever found, were moved into a moist chamber to facilitate fungal outgrowths for verification of B. bassiana infection. The resulting data fit very well to time-dose-mortality model with EF having a larger dose effect (1.05 +/- 0.10) than UC (0.82 +/- 0.11) and also faster time effect. The estimates of the dose- and time-effect parameters were then used to compute lethal concentrations (LC50) and time lengths (LT50). The estimates of LC50 with 95% confidence intervals for both EF and UC were 9.0 (6.9 - 11.6) and 634 (263 - 1532) conidia/mm2 on day 4 after spray, and 3.3 (2.4 - 4.6) and 5.3 (3.2 - 8.6) on day 7, apparently decreasing with increasing time lengths after spray. The estimates of LT50 for EF and UC were 4.9 d and 7.2 d at 5 conidia/mm2, 4.0 d and 5.6 d at 10 conidia/mm2, and 3.2 d and 4.5 d at 100 conidia/mm2, indicating a trend of decrease with increasing counts of conidia attached to the leaves. The results indicate that the emulsifiable formulation of B. bassiana conidia had greater aphidicidal activity than the unformulated conidia. Finally, problems with evaluation of mycoinsecticides and other microbial formulations are discussed and technical standards are recommended.

Animals↗
PubMed2006

Differentiation among populations with migration, mutation, and drift: implications for genetic inference.

Populations may become differentiated from one another as a result of genetic drift. The amounts and patterns of differentiation at neutral loci are determined by local population sizes, migration rates among populations, and mutation rates. We provide exact analytical expressions for the mean, variance, and covariance of a stochastic model for hierarchically structured populations subject to migration, mutation, and drift. In addition to the expected correlation in allele frequencies among populations in the same geographic region, we demonstrate that there is a substantial correlation in allele frequencies among regions at the top level of the hierarchy. We propose a hierarchical Bayesian model for inference of Wright's F-statistics in a two-level hierarchy in which we estimate the among-region correlation in allele frequencies by substituting replication across loci for replication across time. We illustrate the approach through an analysis of human microsatellite data, and we show that approaches ignoring the among-region correlation in allele frequencies underestimate the amount of genetic differentiation among major geographic population groups by approximately 30%. Finally, we discuss the implications of these results for the use and interpretation of F-statistics in evolutionary studies.

Animal Migration↗
PubMed2005

Biological control of Botrytis gray mould and Sclerotinia drop in lettuce.

Research was carried out to evaluate the effectiveness of the biological control of two most important fungal diseases of lettuce (Lactuca sativa L.): 1) Botrytis Gray Mould caused by Botrytis cinerea Pers. ex Fr.; 2) Sclerotinia Drop caused by two pathogenic fungi, Sclerotinia sclerotiorum (Lib.) De Bary and/or Sclerotinia minorJagger. Biological control in lettuce was carried out: 1) using Coniothyrium minitans Campbell, an antagonist fungus that attacks and destroys sclerotia within the soil; 2) identifying lettuce genotypes showing less susceptibility or tolerance. The object of this research was to find control strategies to reduce chemical treatments. The use of resistant varieties is one of the most economical ways to control vegeTable diseases. The lettuce genotypes showing in preliminary trials the best behaviour to the sclerotial diseases were compared in a randomized complete block experiment design and replicated four times. Observations were carried out from February up to April registering the number of diseased plants and yield. The pathogens were isolated on PDA medium and identified. The isolates grown onto PDA plates, after incubation for 6 weeks, allowed obtaining sclerotia that were the target of C. minitans in biological control trials. In laboratory, in controlled conditions, 27 small plots (30 cm in diameter each) with disinfected soil were performed. In 18 plots 9 sclerotia were inoculated (per plot, three of each fungus) and in 9 plots of them a suspension of the antagonist fungus was added. Subsequently, three lettuce varieties were transplanted. For each variety were compared: 1) untreated plots; 2) treated plots with sclerotia only; 3) treated plots with sclerotia and C. minitans suspension. The number of diseased plants was recorded. According to symptom evaluation scale, ranged from 0 (no disease) up to 10 (100% necrotic leaves or dead plants) the plants were grouped into infection classes, calculating the McKinney index. In greenhouse trials, "LM 1307" genotype showed less significant susceptibility to Botrytis Gray Mould (0-2% of affected plants), while "Ninja" and "Charmy" showed 4-11% and 16-26% of diseased plants, respectively. The yields were 69.7, 62.7, 55.3 t/Ha, respectively. In laboratory tests, the McKinney index gave the following results: no disease in all untreated plants; 38.3, 54.2 and 89.2% in "LM 1307", "Ninja" and "Charmy" treated with sclerotia only, respectively; 2.5, 7.5 and 20.8% in "LM 1307", "Ninja" and "Charmy" treated with sclerotia and C. minitans, respectively. In conclusion, the less susceptibility of the genotypes to sclerotial diseases and the use of hyperparasites of sclerotia of phytopathogenic fungi exhibited best results.

Antibiosis↗
PubMed2006

Laboratory and semi-field evaluation of Mosquito Dunks against Aedes aegypti and Aedes albopictus larvae (Diptera: Culicidae).

Laboratory bioassays and semi-field studies were conducted on the efficacy and longevity of Mosquito Dunks (7,000 ITU/mg Bti) in order to determine the concentration-response relationship and the effectiveness on the potency of the Bti product against Aedes mosquito species based on the WHO protocol standard methods and to determine the longevity of release for this product against Ae. aegypti mosquito larvae in water storage containers. This bio-potency study with the late 3rd instar larvae of Ae. aegypti and Ae. albopictus was carried out according to WHO standard protocols. The six concentrations of the Bti product used in each test were replicated 4 times with 25 mosquito larvae. Probit analysis was then used to determine the LC50 and LC95 which was equated with dosages of 1.02 and 1.86 ppm for Ae. aegypti; and 0.39 and 0.84 ppm for Ae. albopictus, which reveals a potency of 382.95 and 303.74 ITU/mg, respectively. The semi-field evaluation of this product in 200-liter earthen jars against 3rd instar larvae of Ae. aegypti showed satisfactory control of greater than 80% at 11 weeks post-treatment.

Aedes↗
PubMed2006

[Chromatin modifications during X-chromosome inactivation in female mammals].

In female mammals, the process of dosage compensation occurs during early embryonic development. As a result of this, one of X-chromosomes becomes transcriptionally inactive. This process is accompanied by chromatin remodeling on inactivated X-chromosome, providing transcriptional silencing of the genes and maintenance of their inactive state. In the present review, the dynamics of modifications occurring during embryonic inactivation, their distribution over the inactive X-chromosome, interaction, and the role in establishing and maintening the inactive state are discussed. As an illustration, modifications on the inactive X-chromosome of the Microtus common vole are presented.

Animals↗
PubMed1991

Decrease of proliferation rate and induction of differentiation by a MYCN antisense DNA oligomer in a human neuroblastoma cell line.

The effects of an antisense oligodeoxynucleotide to codons 2-7 of the oncogene MYCN on the human neuroblastoma cell line LAN-5 were studied. Treated cells showed a decreased MYCN protein expression and synthesis by immunoperoxidase staining and immunoprecipitation. At the same time, the replication rate was inhibited, and the phenotype was modified toward a more differentiated type. Our data suggest the involvement of oncogene MYCN in both proliferative and differentiative processes.

Base Sequence↗
PubMed1978

Parainfluenza-3 virus exposure of beef heifers prior to natural breeding.

Ninety-six Hereford heifers (approximately 7 months of age) were randomly divided into 2 equal groups and housed 1.6 km apart (with 2 replications in time, 1 year apart). At 15 months of age, 1 group/replicate was inoculated with parainfluenza-3 virus, and the other group was given virus-free spent culture medium. Twenty-four hours later, 2 virgin bulls (2 years old) were placed with each group (24 cows) for natural breeding. Viral inoculation caused a twofold increase in parainfluenza-3 titer and a 0.3 C body temperature increase. There was no effect recognized from the virus on natural breeding efficiency.

Animals↗
PubMed1987

The chemical composition and protein quality of amaranth grain germ plasm in Guatemala.

The present research was carried out for the purpose of collecting part of the germ plasm of grain amaranth in Guatemala, as well as to evaluate it in terms of yield, chemical composition and nutritive value. A total of 27 Guatemalan selections, one from Mexico and seven from Peru were planted in June 1982 in 7.5 m2 experimental plots replicated four times. The harvest seed was utilized for analysis of protein, ether extract, crude fiber, tannin content and trypsin inhibitors, as well as for NPR assays. A group of five pooled samples was made based on protein content for amino acid analyses; 10 samples were selected for a second NPR and protein digestibility assay. A preliminary assay on amino acid supplementation of raw grain flour is also reported. The selections were significantly different in grain yield. In general, selections which flowered at a short height and were harvested also at short height, tended to yield more seed. Findings revealed a negative relationship between plant height and grain yield, but a positive relationship between plant height and dry vegetable residue. Protein content of the grain averaged 15.0% with values ranging from 12.8 to 17.4%. Fat content varied from 5.6 to 10.6% with an average of 8.4%. Amaranth grain with a higher protein content contained greater amounts of amino acids on a weight basis, but when these were expressed on a nitrogen basis, differences disappeared. Based on the FAO/WHO amino acid reference pattern, grain amaranth protein was deficient in sulfur amino acids. Although the biological trial corroborated this deficiency, more studies should be undertaken. The NPR values of the samples from Peru averaged 2.30, the one from Mexico 2.04 and those from Guatemala, 2.36. Protein digestibility was 80, 82 and 74%, respectively. The data suggest that there is sufficient variability to select materials of a higher chemical composition, nutritive value, and yield.

Guatemala↗
PubMed1985

Bioassays of Bacillus sphaericus (strain 1593) against mosquitoes of public health importance in Malaysia.

The pathogenicity of Bacillus sphaericus strain 1593 was tested against laboratory-reared larvae of four local species of mosquitoes of public health importance in Malaysia; Aedes aegypti, Anopheles balabacensis, Mansonia uniformis and Culex quinquefasciatus. The bacteria was shake-cultured at 28 +/- 1 degrees C for three days, using Glucose-Yeast Extract Salts medium. After which, the spores and vegetative cells were harvested and stored at 4 degrees C before use. Conditions for bioassays were mean temperature of 25 +/- 1 degrees C and relative humidity 65 +/- 5.0. Twenty third-instar larvae of each species were assayed in 90 ml of diluted spore solution. Each concentration and a control were replicated three times for each bioassay. Larval mortalities at 24 hours and 48 hours were taken and analyzed through Probit Analysis using a computer (IBM 370). LC50 values after 48 hours of exposure showed an increasing order of larval susceptibility as follows: Ae. aegypti (417.70 x 10(4)), An. balabacensis (45.84 x 10(4)), Ma. uniformis (18.23 x 10(4)) and Cx. quinquefasciatus (4.14 x 10(4) spores/ml). With the ability to kill 90% of the Cx. quinquefasciatus larvae tested with just a concentration of 10(5) spores/ml, B. sphaericus (strain 1593) has shown good potential as a biocontrol agent for this species of mosquito.

Animals↗
PubMed1977

Experimental population genetics of meiotic drive systems. I. Pseudo-Y chromosomal drive as a means of eliminating cage populations of Drosophila melanogaster.

The experimental population genetics of Y-chromosome drive in Drosophila melanogaster is approximated by studying the behavior of T(Y;2),SD lines. These exhibit "pseudo-Y" drive through the effective coupling of the Y chromosome to the second chromosome meiotic drive locus, Segregation distorter (SD). T(Y;2),SD males consequently produce only male offspring. When such lines are allowed to compete against structurally normal SD(+) flies in population cages, T(Y;2),SD males increase in frequency according to the dynamics of a simple haploid selection model until the cage population is eliminated as a result of a deficiency in the number of adult females. Cage population extinction generally occurs within about seven generations.-Several conclusions can be drawn from these competition cage studies:(1) Fitness estimates for the T(Y;2),SD lines (relative to SD(+ )) are generally in the range of 2-4, and these values are corroborated by independent estimates derived from studies of migration-selection equilibrium. (2) Fitness estimates are unaffected by cage replication, sample time, or the starting frequency of T(Y;2),SD males, indicating that data from diverse cages can be legitimately pooled to give an overall fitness estimate. (3) Partitioning of the T(Y;2),SD fitnesses into components of viability, fertility, and frequency of alternate segregation (Y + SD from X + SD(+)) suggests that most of the T(Y;2),SD advantage derives from the latter two components. Improvements in the system might involve increasing both the viability and the alternate segregation to increase the total fitness. While pseudo-Y drive operates quite effectively against laboratory stocks, it is less successful in eliminating wild-type populations which are already segregating for suppressors of SD action. This observation suggests that further studies into the origin and rate of accumulation of suppressors of meiotic drive are needed before an overall assessment can be made of the potential of Y-chromosome drive as a tool for population control.

Animals↗
PubMed1984

Deprival of nicotinamide leads to enhanced glucose transport in chick embryo fibroblasts.

Chick embryo fibroblasts growing in medium free of pyridine ring precursors of NADH and NADPH replicate several times before multiplication ceases. The rate of glucose transport is progressively enhanced, finally reaching levels several times higher than those normally observed in cells severely depleted of NADH. Whereas normal cells respond to additional glucose by further reducing transport, the NADH-depleted cell is refractory to glucose even at five times the normal glucose concentration. Readdition of nicotinamide does little to restore normal transport within 24 h. On the other hand NAD+ or NADP+ provided simultaneously with glucose results in a sharp decline in measurable transport within 2-4 h. The role of the pyridine nucleotides in this reduction of transport function is for the moment unknown.

3-O-Methylglucose↗
PubMed1984

Pineal and melatonin actions in reproductive endocrinology.

Daylength is the major environmental variable governing seasonal breeding, and the pineal gland is needed for this response to occur in many photosensitive species. Although dependent upon the integrity of its peripheral sympathetic innervation, the pineal has no efferent projections, and therefore it affects neuroendocrine function by humoral means. Melatonin has been proposed as the pineal hormone; its timed administration replicate the effect of daylength on seasonal breeding in several mammals, including long-day, like the hamster, and short-day breeders, like the sheep. The pineal is regulated primarily by photo-periodic information attaining the gland through a polysynaptic pathway initiated in the retinohypothalamic tract. Secondary regulators of pineal secretory activity are several steroid and polypeptide hormones. Melatonin synthesis is maximal during nighttime while during daylight it is suppressed. Melatonin acts on specific receptor sites at hypothalamic and perhaps extrahypothalamic sites to affect LHRH release. Changes in calcium fluxes, cyclic nucleotide and prostaglandin synthesis may underlie the neuroendocrine activity of melatonin at hypothalamic sites.

Animals↗
PubMedDate not supplied

A comparison of avian and mammalian cell cultures for the propagation of avian reovirus WVU 2937.

Two avian and seven mammalian cell lines were evaluated for their application in propagating avian reovirus WVU 2937. Cultures were compared for monolayer-formation time, support of viral replication, passages and postinfection time required for expression of cytopathic effect (CPE), type of CPE, and virus yield. CPE was observed on the first passage with infected egg yolk in primary chicken embryo kidney cells, primary through tertiary chicken embryo liver (CEL) cells, and African green monkey kidney (VERO) cells; on the third blind passage of infected supernatant in Georgia bovine kidney cells, Crandall feline kidney cells, and baby hamster cells; on the fifth blind passage in rabbit kidney cells; and on the tenth blind passage in porcine kidney cells. CPE was not observed after 10 viral passages in rabbit bone-marrow cells. Monolayer formation time and postinfection time for CPE expression occurred sooner, and virus yield was greater, with CEL and VERO cells than with other cell lines.

Animals↗
PubMed1978

Growth curve changes associated with long-term selection for body weight in Japanese quail.

Four quail lines were utilized to investigate growth patterns in quail. Three of these lines (P, T and S) had previously undergone long-term selection for high 4-week body weight, while line C was maintained as a nonselected control. Quail progeny from generation 37 and 38 breeders were fed diets containing 28% and 20% protein. Within each trial, the diet/line treatments were replicated 3 times with 12 quail per subclass. Body weight measurements suggested that the growth of all lines was best approximated by the logistic growth curve model. When fed a 28% protein diet the age at maximum growth (point of inflection) of selected lines was 4 to 6 days earlier than the corresponding age of controls. Similar rates of gain after 4 weeks of age between selected and control lines suggested that mechanisms influenced by selection for 4-week body weight in quail operate only during the period prior to the age at selection with little or no residual effect.

Analysis of Variance↗