Topic
Spots
About: Spots is a research topic. Over the lifetime, 149 publications have been published within this topic receiving 1767 citations.
Papers published on a yearly basis
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Papers
TL;DR: This study demonstrated the suitability of filter paper blood spots paper for collection of serum antibodies, and provided clear guidelines for the treatment and storage of filter papers which emphasize the importance of desiccation and minimisation of time spent at ambient temperatures.
Abstract: Blood spots collected onto filter paper are an established and convenient source of antibodies for serological diagnosis and epidemiological surveys. Although recommendations for the storage and analysis of small molecule analytes in blood spots exist, there are no published systematic studies of the stability of antibodies under different storage conditions. Blood spots, on filter paper or glass fibre mats and containing malaria-endemic plasma, were desiccated and stored at various temperatures for different times. Eluates of these spots were assayed for antibodies against two Plasmodium falciparum antigens, MSP-119 and MSP2, and calculated titres used to fit an exponential (first order kinetic) decay model. The first order rate constants (k) for each spot storage temperature were used to fit an Arrhenius equation, in order to estimate the thermal and temporal stability of antibodies in dried blood spots. The utility of blood spots for serological assays was confirmed by comparing antibodies eluted from blood spots with the equivalent plasma values in a series of samples from North Eastern Tanzania and by using blood spot-derived antibodies to estimate malaria transmission intensity in this site and for two localities in Uganda. Antibodies in spots on filter paper and glass fibre paper had similar stabilities but blood was more easily absorbed onto filter papers than glass fibre, spots were more regular and spot size was more closely correlated with blood volume for filter paper spots. Desiccated spots could be stored at or below 4°C for extended periods, but were stable for only very limited periods at ambient temperature. When desiccated, recoveries of antibodies that are predominantly of IgG1 or IgG3 subclasses were similar. Recoveries of antibodies from paired samples of serum and of blood spots from Tanzania which had been suitably stored showed similar recoveries of antibodies, but spots which had been stored for extended periods at ambient humidity and temperature showed severe loss of recoveries. Estimates of malaria transmission intensity obtained from serum and from blood spots were similar, and values obtained using blood spots agreed well with entomologically determined values. This study has demonstrated the suitability of filter paper blood spots paper for collection of serum antibodies, and provided clear guidelines for the treatment and storage of filter papers which emphasize the importance of desiccation and minimisation of time spent at ambient temperatures. A recommended protocol for collecting, storing and assaying blood spots is provided.
263 citations
TL;DR: Fungicides in the benzimidazole and triazole class as well as organotin derivatives and strobilurins have successfully been used to control Cercospora leaf spot.
Abstract: SUMMARY
Leaf spot disease caused by Cercospora beticola Sacc. is the most destructive foliar pathogen of sugarbeet worldwide. In addition to reducing yield and quality of sugarbeet, the control of leaf spot disease by extensive fungicide application incurs added costs to producers and repeatedly has selected for fungicide-tolerant C. beticola strains. The genetics and biochemistry of virulence have been examined less for C. beticola as compared with the related fungi C. nicotianae, C. kikuchii and C. zeae-maydis, fungi to which the physiology of C. beticola is often compared. C. beticola populations generally are not characterized as having race structure, although a case of race-specific resistance in sugarbeet to C. beticola has been reported. Resistance currently implemented in the field is quantitatively inherited and exhibits low to medium heritability.
Taxonomy: Cercospora beticola Sacc.; Kingdom Fungi, Subdivision Deuteromycetes, Class Hyphomycetes, Order Hyphales, Genus Cercospora.
Identification: Circular, brown to red delimited spots with ashen-grey centre, 0.5–6 mm diameter; dark brown to black stromata against grey background; pale brown unbranched sparingly septate conidiophores, hyaline acicular conidia, multiseptate, from 2.5 to 4 µm wide and 50–200 µm long.
Host range: Propagative on Beta vulgaris and most species of Beta. Reported on members of the Chenopodiaceae and on Amaranthus.
Disease symptoms: Infected leaves and petioles of B. vulgaris exhibit numerous circular leaf spots that coalesce in severe cases causing complete leaf collapse. Dark specks within a grey spot centre are characteristic for the disease. Older leaves exhibit a greater number of lesions with larger spot diameter. During the latter stage of severe epiphytotics, new leaf growth can be seen emerging from the plant surrounded by prostrate, collapsed leaves.
Control: Fungicides in the benzimidazole and triazole class as well as organotin derivatives and strobilurins have successfully been used to control Cercospora leaf spot. Elevated levels of tolerance in populations of C. beticola to some of the chemicals registered for control has been documented. Partial genetic resistance also is used to reduce leaf spot disease.
179 citations
TL;DR: The spots of G. diffusa mimic resting flies, thereby eliciting mate-seeking and aggregation responses in fly pollinators, and differences in epidermal sculpturing may partly explain the UV reflectance pattern of these spots, which is similar to that of the flies.
Abstract: We investigated the functional significance of raised black spots on the ray florets of Gorteria diffusa (Asteraceae) in South Africa Field observations showed that G diffusa is pollinated by a small bee-fly, Megapalpus nitidus (Bombyliidae), which is strikingly similar to the raised spots that occur on some of the ray florets Removal of the spots resulted in a significant decrease in the rate of fly visits to capitula, but did not significantly affect seed set Replacement of the spots with simple ink spots also significantly reduced the rate of pollinator visits, suggesting that flies respond to details in the structure of the spots Investigations using scanning electron microscopy showed that the spots of G diffusa consist of a complex of different cell types Differences in epidermal sculpturing may partly explain the UV reflectance pattern of these spots, which is similar to that of the flies Male flies are strongly attracted to the spots, as well as to other flies sitting in the capitula, although female flies also visit the capitula We conclude that the spots of G diffusa mimic resting flies, thereby eliciting mate-seeking and aggregation responses in fly pollinators Similar dark spots have evolved in unrelated South African Gazania, Dimorphotheca, and Pelargonium species pollinated by bee-flies
122 citations
TL;DR: A protocol for protein extraction from mycelium tissue, with protein separation by 2‐DE and MS analysis, was optimised as a first approach to defining the B. cinerea proteome.
Abstract: Botrytis cinerea is a phytopathogenic fungi causing disease in a number of important crops. It is considered a very complex species in which different populations seem to be adapted to different hosts. In order to characterize fungal virulence factors, a proteomic research was started. A protocol for protein extraction from mycelium tissue, with protein separation by 2-DE and MS analysis, was optimised as a first approach to defining the B. cinerea proteome. Around 400 spots were detected in 2-DE CBB-stained gels, covering the 5.4-7.7 pH and 14-85 kDa ranges. The averages of analytical and biological coefficients of variance for 64 independent spots were 16.1% and 37.5%, respectively. Twenty-two protein spots were identified by MALDI-TOF or ESI IT MS/MS, with some of them corresponding to forms of malate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase. Two more spots matched a cyclophilin and a protein with an unknown function.
89 citations
TL;DR: The data suggest that NaN3 causes non-disjunction in this material, and it is suggested that the pattern of action of a given mutagen can be studied by analyzing the relative increase of different types of spots.
Abstract: The light green, Y11y11, plants of varieties T219 and L65-1237 of soybean have some dark green, yellow and twin (or double) spots resembling the phenotypes controlled by Y11Y11, y11y11 and Y11Y11–y11y11 genotypes, respectively. The process of somatic crossing over is considered responsible for the origin of double spots. Some of the single spots, undoubtedly, originate by failure of one of the two components of the double spots. Non-disjunction, segmental losses and/or point mutations are also inferred to cause some of the spots seen on the heterozygous Y11y11 plants as well as light green spots seen on the Y11Y11 and y11y11 homozygotes. When seeds are treated with caffeine, mitomycin C or 3H2O the increase in the frequency of all three types of spots on the Y11y11 leaves is parellel. Somatic crossing over is considered as the major, common basis for the origin of spots. The treatment with sodium azide (NaN3) increases, on the Y11Y11 plants, the frequency of dark green and yellow spots equally; doubles increase only slightly or not at all. The y11y11 plants lack any spots. The data suggest that NaN3 causes non-disjunction in this material. γ-Rays, on the other hand, increase the frequency of yellow spots much more than that of dark greens or doubles on Y11y11 leaves. Also light green spots are found on y11y11 as well as Y11Y11 plants. These data may mean that spots result from somatic crossing over, point mutations and segmental losses. A list of many other agents tested is included. Because different mutagens increase the frequency of the three types of spots, either equally or differentially, it is suggested that the pattern of action of a given mutagen can be studied by analyzing the relative increase of different types of spots. This material provides the investigator with a eukaryotic, in vivo test system which is relatively rapid and inexpensive.
67 citations
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Performance Metrics
| Year | Papers |
|---|---|
| 2026 | 1 |
| 2025 | 195 |
| 2024 | 369 |
| 2023 | 505 |
| 2022 | 574 |
| 2021 | 98 |