Angel Alejo - Academia.edu (original) (raw)
Papers by Angel Alejo
Chemico-biological Interactions, 1999
The present study shows the existence of both Ca 2 + -dependent and EDTA-resistant hydrolysing ac... more The present study shows the existence of both Ca 2 + -dependent and EDTA-resistant hydrolysing activities against HDCP and paraoxon in the particulate and soluble fractions of hen, rat and rabbit liver. HDCP was more extensively hydrolysed than paraoxon in both subcellular fractions and each of three individuals of the three animal species under study in spite of wide interindividual variations. However the ratio of HDCP versus paraoxon hydrolysing activity (HDCPase/paraoxonase), although within the same order of magnitude, cannot be considered as constant as it ranges one-to seven-fold between individuals of the same species. Also there is no constant ratio of Ca 2 + -dependent/EDTA-resistant activities. Rabbit liver showed the highest rates of Ca 2 + -dependent hydrolysis for both organophosphorus compounds whereas the hen paraoxonase activity was not inhibited by EDTA. The stereospecific hydrolysis of HDCP was mostly a Ca 2 + -dependant one, the S-HDCP isomer being hydrolysed faster than the R-HDCP one. The suggestion is made that HDCP could be conveniently used to measure PTE activity in the liver.
Atmospheric Environment, 2003
This paper describes an assessment of environmental exposure to fluorine in the surroundings of a... more This paper describes an assessment of environmental exposure to fluorine in the surroundings of an aluminium smelter, carried out by measuring fluorine concentrations in the tissues of mosses growing in the area. Forty-two samples were collected from within a 3300 m of radius of the smelter on two different occasions. Samples of either Hypnum cupressiforme Hedw. or Scleropodium purum (Hedw.) Limpr. were collected at each point, depending on which was the most abundant. The fluorine contents in the samples varied from o10 mg g À1 F (the limit of quantification of the analytical technique used) to 154 mg g À1 F. To analyse the spatial pattern of fluorine accumulation in the mosses, response surfaces were adjusted to the data using the geographic coordinates of the sampling points as independent variables. Details are given of the process used to select the best surface from among the many candidates available. The graphical and mathematical analyses of the surfaces allowed description of the effect of the distance from the smelter on fluorine concentration and of the spatial anisotropy, i.e. the existence of directions along which fluorine deposition is enhanced. Fluorine concentration decreased exponentially over all the study area, therefore the impact of the smelter decreased greatly within a short distance. The surfaces also allowed detection of differences between sampling times, in terms of the prevailing direction of pollutant movement, as well as differences in the rates of decrease in concentration with distance from the plant. Finally, it is discussed how the particular characteristics of the source of the pollutant affect its dispersal, and how some sampling difficulties encountered affected the results obtained. r
Atmospheric Environment, 2008
The present study involved intercalibration of the concentrations of Al, As, Be, Cd, Co, Cr, Cu, ... more The present study involved intercalibration of the concentrations of Al, As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn in two species of terrestrial mosses, Pseudoscleropodium purum and Hypnum cupressiforme, collected in Galicia (NW Spain). The moss samples were collected from highly contaminated areas as well as areas with intermediate levels of contamination. Intercalibration was performed by type II regressions, and differences in the bioconcentration capacity of the two species were analyzed by ANCOVA. The slopes and elevations of the regression lines were well characterized and the lines obtained enabled intercalibration of a wide range of concentrations. The high values of the coefficients of determination for Cd, Cr, Fe, Hg, Mn, Pb, V, and Zn, allowed practical application of intercalibration because noise was reduced in the final data set. The high values of the slopes of the regression lines for some elements suggest that data corresponding to these species should not be used simultaneously without it first being transformed by the corresponding intercalibration line. In general terms, H. cupressiforme has a higher bioconcentration capacity than P. purum; this cannot be explained by differences in the concentration of uronic acids in the cell wall, the level of desesterification of these acids, the cationic exchange capacity of the species. However, the differences between species may be explained by morphological differences or differences in specific surface area. r
Chemosphere, 2008
In the present study the effects of gender, age and nutritional status on tissue concentrations o... more In the present study the effects of gender, age and nutritional status on tissue concentrations of some trace elements (Zn, Cu, Mn, and Cr) in wood mouse (Apodemus sylvaticus), Spanish shrew (Sorex granarius), and great white-toothed shrew (Crocidura russula) were investigated. Four sampling stations were selected for the study: a restored mine dump, an area characterised by ultrabasic soil and two sites in oak woods in the vicinity of a power plant. Gender had no effect on the tissue concentrations of the metals studied, except for the concentration of Zn in brain tissue from C. russula. The relative age of the individuals was estimated on the basis of crystalline lens weight in mice and dental abrasion in shrews, as body weight was considered a poor indicator of age because of the strong interindividual overlap in the populations. Age was only significantly (and negatively) correlated with the concentration of Cr in livers of mice from one station, a finding that may indicate physiological stress on growth at this site. The nutritional status was estimated from the body mass index; the relationships between this index and metal concentrations for both A. sylvaticus and C. russula were negative, which can be attributed to the weight-specific metabolic rate that leads to a relatively low uptake of metals per unit of body weight. As there was no relation between duration of exposure and concentrations of metals in the organs analysed, age should not be included as a variable factor in the condition index.
Ecotoxicology and Environmental Safety, 2010
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
Environmental Pollution, 2000
apsule'': When comparing responses of native versus transplanted moss (Scleropodium purum) to a t... more apsule'': When comparing responses of native versus transplanted moss (Scleropodium purum) to a thermal power plant, high levels of selenium were found in native mosses, indicating adaptation.
Archives of Environmental Contamination and Toxicology, 2008
In the present study, we determined the concentrations of Cu, Fe, Mn, and Zn in soil and several ... more In the present study, we determined the concentrations of Cu, Fe, Mn, and Zn in soil and several trophic compartments at a total of 16 sampling stations. The trophic compartments studied were primary producers, represented by two species of terrestrial mosses (Pseudoescleropodium purum and Hypnum cupressiforme) and oak trees (Quercus robur or Q. pyrenaica); primary consumers, represented by the wood mouse (Apodemus sylvaticus) and the yellow necked mouse (A. flavicollis); secondary consumers, represented by the shrew (Sorex granarius); and finally, detritivores, represented by slugs (Arion ater). Thirteen of the sampling stations were located in mature oak woodlands (Quercus sp.); two of the sampling stations were located in the area surrounding a restored lignite mine dump, and the other in an ultrabasic area. The analytical determinations revealed a lack of significant correlations among trophic compartments, possibly caused by effective regulation of metals by organisms and/or spatial variation in availability of metals from soil or food. Furthermore, the only element that showed a clear pattern of biomagnification was Cu; as for the other elements, there was always some divergence from such a pattern. Finally, the patterns of bioaccumulation in contaminated and woodland sampling stations were very similar, although there was enrichment of the concentrations of Cu, Mn, and Zn in the mice viscera, which, except for Mn, were related to higher edaphic concentrations.
Chemosphere, 2004
For the first time, the concepts of limit of detection and limit of quantification, commonly used... more For the first time, the concepts of limit of detection and limit of quantification, commonly used in analytical chemistry, are applied to the field of active biomonitoring with terrestrial mosses, using the controls as blanks so that the limits indicate the error associated with the transplant technique. The application of these concepts to data corresponding to Hg concentrations in the surroundings of a chlor-alkali plant and a power plant, makes interpretation of the results easier by providing better spatial and temporal coherence. This procedure may allow improvement in the standardization of active biomonitoring techniques as it is applicable to all kinds of biomonitors. One disadvantage of the application of the limit of detection and limit of quantification is that they only take into account the a error, or risk of false positives, and do not take into account the b error, or risk of false negatives.
Water Air and Soil Pollution, 2011
The sequential elution technique (SET) is used to determine the distribution of elements in the d... more The sequential elution technique (SET) is used to determine the distribution of elements in the different cell fractions of mosses. The extracellular extractants most commonly used in this technique are NiCl2 and EDTA, although there are certain disadvantages associated with their use. In order to avoid such problems, we searched for new extractants that displace extracellularly bound metals, either because they are present at high concentrations (Ca) or because they have a high affinity for cation exchange sites (Hg and Au). The compounds HCl, NaCl, and CaCl2 were tested as extractants of the former type, as possible alternatives for the determination of extracellular metals in the moss Pseudoscleropodium purum. Calcium chloride was finally chosen as is it potentially the most successful in terms of binding to the cation exchange sites without altering the membrane permeability. The concentration chosen was 160 mM, as this yielded maximum displacement of Zn without membrane alterations. An experiment was then carried out to test the efficiency of Ca in extracting extracellular Zn, under laboratory and field conditions. In addition, Hg and Au were tested, at different concentrations, as extractants with high affinity for cation exchange sites, as neither of these elements has previously been used in the SET, and both display electronic characteristics that suggest their potential usefulness in displacing other cations from cation exchange sites. The results obtained show that extraction of extracellularly bound metal by high concentrations of Ca should be ruled out, as total extraction of Zn was not achieved. Both Hg and Au produced membrane alterations at low concentrations and moreover, neither was more efficient at extracting Zn than the reference extractant (20 mM NiCl2).
Critical Reviews in Biotechnology, 2008
Among Cucurbitaceae, Cucumis melo is one of the most important cultivated cucurbits. They are gro... more Among Cucurbitaceae, Cucumis melo is one of the most important cultivated cucurbits. They are grown primarily for their fruit, which generally have a sweet aromatic flavor, with great diversity and size (50 g to 15 kg), flesh color (orange, green, white, and pink), rind color (green, yellow, white, orange, red, and gray), form (round, flat, and elongated), and dimension (4 to 200 cm). C. melo can be broken down into seven distinct types based on the previously discussed variations in the species. The melon fruits can be either climacteric or nonclimacteric, and as such, fruit can adhere to the stem or have an abscission layer where they will fall from the plant naturally at maturity. Traditional plant breeding of melons has been done for 100 years wherein plants were primarily developed as open-pollinated cultivars. More recently, in the past 30 years, melon improvement has been done by more traditional hybridization techniques. An improvement in germplasm is relatively slow and is limited by a restricted gene pool. Strong sexual incompatibility at the interspecific and intergeneric levels has restricted rapid development of new cultivars with high levels of disease resistance, insect resistance, flavor, and sweetness. In order to increase the rate and diversity of new traits in melon it would be advantageous to introduce new genes needed to enhance both melon productivity and melon fruit quality. This requires plant tissue and plant transformation techniques to introduce new or foreign genes into C. melo germplasm. In order to achieve a successful commercial application from biotechnology, a competent plant regeneration system of in vitro cultures for melon is required. More than 40 in vitro melon regeneration programs have been reported; however, regeneration of the various melon types has been highly variable and in some cases impossible. The reasons for this are still unknown, but this plays a heavy negative role on trying to use plant transformation technology to improve melon germplasm. In vitro manipulation of melon is difficult; genotypic responses to the culture method (i.e., organogenesis, somatic embryogenesis, etc.) as well as conditions for environmental and hormonal requirements for plant growth and regeneration continue to be poorly understood for developing simple in vitro procedures to culture and transform all C. melo genotypes. In many cases, this has to be done on an individual line basis. The present paper describes the various research findings related to successful approaches to plant regeneration and transgenic transformation of C. melo. It also describes potential improvement of melon to improve fruit quality characteristics and postharvest handling. Despite more than 140 transgenic melon field trials in the United States in 1996, there are still no commercial transgenic melon cultivars on the market. This may be a combination of technical or performance
Pediatric Infectious Disease Journal, 1995
Analysis of restriction fragment length polymorphisms is a well-established method of "D... more Analysis of restriction fragment length polymorphisms is a well-established method of "DNA fingerprinting" that has been used to trace the transmission of particular strains of Mycobacterium tuberculosis during investigations of outbreaks. This report describe the use of restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis to investigate two outbreaks of tuberculosis that affected six children who attended two pediatric wards in our hospital. In both outbreaks a history of household exposure to an adult with M. tuberculosis was obtained and suspected tuberculous contacts were identified. We have demonstrated unequivocally the strain relationship among the isolates in all the cases by restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis. These techniques are very useful for performing epidemiologic studies of tuberculosis in children where natural history of tuberculosis infection is different from that in adults in that it is almost always primary infection rather than reactivation.
Pediatric Infectious Disease Journal, 1995
Analysis of restriction fragment length polymorphisms is a well-established method of "D... more Analysis of restriction fragment length polymorphisms is a well-established method of "DNA fingerprinting" that has been used to trace the transmission of particular strains of Mycobacterium tuberculosis during investigations of outbreaks. This report describe the use of restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis to investigate two outbreaks of tuberculosis that affected six children who attended two pediatric wards in our hospital. In both outbreaks a history of household exposure to an adult with M. tuberculosis was obtained and suspected tuberculous contacts were identified. We have demonstrated unequivocally the strain relationship among the isolates in all the cases by restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis. These techniques are very useful for performing epidemiologic studies of tuberculosis in children where natural history of tuberculosis infection is different from that in adults in that it is almost always primary infection rather than reactivation.
Pediatric Infectious Disease Journal, 1995
Analysis of restriction fragment length polymorphisms is a well-established method of "D... more Analysis of restriction fragment length polymorphisms is a well-established method of "DNA fingerprinting" that has been used to trace the transmission of particular strains of Mycobacterium tuberculosis during investigations of outbreaks. This report describe the use of restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis to investigate two outbreaks of tuberculosis that affected six children who attended two pediatric wards in our hospital. In both outbreaks a history of household exposure to an adult with M. tuberculosis was obtained and suspected tuberculous contacts were identified. We have demonstrated unequivocally the strain relationship among the isolates in all the cases by restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis. These techniques are very useful for performing epidemiologic studies of tuberculosis in children where natural history of tuberculosis infection is different from that in adults in that it is almost always primary infection rather than reactivation.
Chemico-biological Interactions, 1999
The present study shows the existence of both Ca 2 + -dependent and EDTA-resistant hydrolysing ac... more The present study shows the existence of both Ca 2 + -dependent and EDTA-resistant hydrolysing activities against HDCP and paraoxon in the particulate and soluble fractions of hen, rat and rabbit liver. HDCP was more extensively hydrolysed than paraoxon in both subcellular fractions and each of three individuals of the three animal species under study in spite of wide interindividual variations. However the ratio of HDCP versus paraoxon hydrolysing activity (HDCPase/paraoxonase), although within the same order of magnitude, cannot be considered as constant as it ranges one-to seven-fold between individuals of the same species. Also there is no constant ratio of Ca 2 + -dependent/EDTA-resistant activities. Rabbit liver showed the highest rates of Ca 2 + -dependent hydrolysis for both organophosphorus compounds whereas the hen paraoxonase activity was not inhibited by EDTA. The stereospecific hydrolysis of HDCP was mostly a Ca 2 + -dependant one, the S-HDCP isomer being hydrolysed faster than the R-HDCP one. The suggestion is made that HDCP could be conveniently used to measure PTE activity in the liver.
Atmospheric Environment, 2003
This paper describes an assessment of environmental exposure to fluorine in the surroundings of a... more This paper describes an assessment of environmental exposure to fluorine in the surroundings of an aluminium smelter, carried out by measuring fluorine concentrations in the tissues of mosses growing in the area. Forty-two samples were collected from within a 3300 m of radius of the smelter on two different occasions. Samples of either Hypnum cupressiforme Hedw. or Scleropodium purum (Hedw.) Limpr. were collected at each point, depending on which was the most abundant. The fluorine contents in the samples varied from o10 mg g À1 F (the limit of quantification of the analytical technique used) to 154 mg g À1 F. To analyse the spatial pattern of fluorine accumulation in the mosses, response surfaces were adjusted to the data using the geographic coordinates of the sampling points as independent variables. Details are given of the process used to select the best surface from among the many candidates available. The graphical and mathematical analyses of the surfaces allowed description of the effect of the distance from the smelter on fluorine concentration and of the spatial anisotropy, i.e. the existence of directions along which fluorine deposition is enhanced. Fluorine concentration decreased exponentially over all the study area, therefore the impact of the smelter decreased greatly within a short distance. The surfaces also allowed detection of differences between sampling times, in terms of the prevailing direction of pollutant movement, as well as differences in the rates of decrease in concentration with distance from the plant. Finally, it is discussed how the particular characteristics of the source of the pollutant affect its dispersal, and how some sampling difficulties encountered affected the results obtained. r
Atmospheric Environment, 2008
The present study involved intercalibration of the concentrations of Al, As, Be, Cd, Co, Cr, Cu, ... more The present study involved intercalibration of the concentrations of Al, As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn in two species of terrestrial mosses, Pseudoscleropodium purum and Hypnum cupressiforme, collected in Galicia (NW Spain). The moss samples were collected from highly contaminated areas as well as areas with intermediate levels of contamination. Intercalibration was performed by type II regressions, and differences in the bioconcentration capacity of the two species were analyzed by ANCOVA. The slopes and elevations of the regression lines were well characterized and the lines obtained enabled intercalibration of a wide range of concentrations. The high values of the coefficients of determination for Cd, Cr, Fe, Hg, Mn, Pb, V, and Zn, allowed practical application of intercalibration because noise was reduced in the final data set. The high values of the slopes of the regression lines for some elements suggest that data corresponding to these species should not be used simultaneously without it first being transformed by the corresponding intercalibration line. In general terms, H. cupressiforme has a higher bioconcentration capacity than P. purum; this cannot be explained by differences in the concentration of uronic acids in the cell wall, the level of desesterification of these acids, the cationic exchange capacity of the species. However, the differences between species may be explained by morphological differences or differences in specific surface area. r
Chemosphere, 2008
In the present study the effects of gender, age and nutritional status on tissue concentrations o... more In the present study the effects of gender, age and nutritional status on tissue concentrations of some trace elements (Zn, Cu, Mn, and Cr) in wood mouse (Apodemus sylvaticus), Spanish shrew (Sorex granarius), and great white-toothed shrew (Crocidura russula) were investigated. Four sampling stations were selected for the study: a restored mine dump, an area characterised by ultrabasic soil and two sites in oak woods in the vicinity of a power plant. Gender had no effect on the tissue concentrations of the metals studied, except for the concentration of Zn in brain tissue from C. russula. The relative age of the individuals was estimated on the basis of crystalline lens weight in mice and dental abrasion in shrews, as body weight was considered a poor indicator of age because of the strong interindividual overlap in the populations. Age was only significantly (and negatively) correlated with the concentration of Cr in livers of mice from one station, a finding that may indicate physiological stress on growth at this site. The nutritional status was estimated from the body mass index; the relationships between this index and metal concentrations for both A. sylvaticus and C. russula were negative, which can be attributed to the weight-specific metabolic rate that leads to a relatively low uptake of metals per unit of body weight. As there was no relation between duration of exposure and concentrations of metals in the organs analysed, age should not be included as a variable factor in the condition index.
Ecotoxicology and Environmental Safety, 2010
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
Environmental Pollution, 2000
apsule'': When comparing responses of native versus transplanted moss (Scleropodium purum) to a t... more apsule'': When comparing responses of native versus transplanted moss (Scleropodium purum) to a thermal power plant, high levels of selenium were found in native mosses, indicating adaptation.
Archives of Environmental Contamination and Toxicology, 2008
In the present study, we determined the concentrations of Cu, Fe, Mn, and Zn in soil and several ... more In the present study, we determined the concentrations of Cu, Fe, Mn, and Zn in soil and several trophic compartments at a total of 16 sampling stations. The trophic compartments studied were primary producers, represented by two species of terrestrial mosses (Pseudoescleropodium purum and Hypnum cupressiforme) and oak trees (Quercus robur or Q. pyrenaica); primary consumers, represented by the wood mouse (Apodemus sylvaticus) and the yellow necked mouse (A. flavicollis); secondary consumers, represented by the shrew (Sorex granarius); and finally, detritivores, represented by slugs (Arion ater). Thirteen of the sampling stations were located in mature oak woodlands (Quercus sp.); two of the sampling stations were located in the area surrounding a restored lignite mine dump, and the other in an ultrabasic area. The analytical determinations revealed a lack of significant correlations among trophic compartments, possibly caused by effective regulation of metals by organisms and/or spatial variation in availability of metals from soil or food. Furthermore, the only element that showed a clear pattern of biomagnification was Cu; as for the other elements, there was always some divergence from such a pattern. Finally, the patterns of bioaccumulation in contaminated and woodland sampling stations were very similar, although there was enrichment of the concentrations of Cu, Mn, and Zn in the mice viscera, which, except for Mn, were related to higher edaphic concentrations.
Chemosphere, 2004
For the first time, the concepts of limit of detection and limit of quantification, commonly used... more For the first time, the concepts of limit of detection and limit of quantification, commonly used in analytical chemistry, are applied to the field of active biomonitoring with terrestrial mosses, using the controls as blanks so that the limits indicate the error associated with the transplant technique. The application of these concepts to data corresponding to Hg concentrations in the surroundings of a chlor-alkali plant and a power plant, makes interpretation of the results easier by providing better spatial and temporal coherence. This procedure may allow improvement in the standardization of active biomonitoring techniques as it is applicable to all kinds of biomonitors. One disadvantage of the application of the limit of detection and limit of quantification is that they only take into account the a error, or risk of false positives, and do not take into account the b error, or risk of false negatives.
Water Air and Soil Pollution, 2011
The sequential elution technique (SET) is used to determine the distribution of elements in the d... more The sequential elution technique (SET) is used to determine the distribution of elements in the different cell fractions of mosses. The extracellular extractants most commonly used in this technique are NiCl2 and EDTA, although there are certain disadvantages associated with their use. In order to avoid such problems, we searched for new extractants that displace extracellularly bound metals, either because they are present at high concentrations (Ca) or because they have a high affinity for cation exchange sites (Hg and Au). The compounds HCl, NaCl, and CaCl2 were tested as extractants of the former type, as possible alternatives for the determination of extracellular metals in the moss Pseudoscleropodium purum. Calcium chloride was finally chosen as is it potentially the most successful in terms of binding to the cation exchange sites without altering the membrane permeability. The concentration chosen was 160 mM, as this yielded maximum displacement of Zn without membrane alterations. An experiment was then carried out to test the efficiency of Ca in extracting extracellular Zn, under laboratory and field conditions. In addition, Hg and Au were tested, at different concentrations, as extractants with high affinity for cation exchange sites, as neither of these elements has previously been used in the SET, and both display electronic characteristics that suggest their potential usefulness in displacing other cations from cation exchange sites. The results obtained show that extraction of extracellularly bound metal by high concentrations of Ca should be ruled out, as total extraction of Zn was not achieved. Both Hg and Au produced membrane alterations at low concentrations and moreover, neither was more efficient at extracting Zn than the reference extractant (20 mM NiCl2).
Critical Reviews in Biotechnology, 2008
Among Cucurbitaceae, Cucumis melo is one of the most important cultivated cucurbits. They are gro... more Among Cucurbitaceae, Cucumis melo is one of the most important cultivated cucurbits. They are grown primarily for their fruit, which generally have a sweet aromatic flavor, with great diversity and size (50 g to 15 kg), flesh color (orange, green, white, and pink), rind color (green, yellow, white, orange, red, and gray), form (round, flat, and elongated), and dimension (4 to 200 cm). C. melo can be broken down into seven distinct types based on the previously discussed variations in the species. The melon fruits can be either climacteric or nonclimacteric, and as such, fruit can adhere to the stem or have an abscission layer where they will fall from the plant naturally at maturity. Traditional plant breeding of melons has been done for 100 years wherein plants were primarily developed as open-pollinated cultivars. More recently, in the past 30 years, melon improvement has been done by more traditional hybridization techniques. An improvement in germplasm is relatively slow and is limited by a restricted gene pool. Strong sexual incompatibility at the interspecific and intergeneric levels has restricted rapid development of new cultivars with high levels of disease resistance, insect resistance, flavor, and sweetness. In order to increase the rate and diversity of new traits in melon it would be advantageous to introduce new genes needed to enhance both melon productivity and melon fruit quality. This requires plant tissue and plant transformation techniques to introduce new or foreign genes into C. melo germplasm. In order to achieve a successful commercial application from biotechnology, a competent plant regeneration system of in vitro cultures for melon is required. More than 40 in vitro melon regeneration programs have been reported; however, regeneration of the various melon types has been highly variable and in some cases impossible. The reasons for this are still unknown, but this plays a heavy negative role on trying to use plant transformation technology to improve melon germplasm. In vitro manipulation of melon is difficult; genotypic responses to the culture method (i.e., organogenesis, somatic embryogenesis, etc.) as well as conditions for environmental and hormonal requirements for plant growth and regeneration continue to be poorly understood for developing simple in vitro procedures to culture and transform all C. melo genotypes. In many cases, this has to be done on an individual line basis. The present paper describes the various research findings related to successful approaches to plant regeneration and transgenic transformation of C. melo. It also describes potential improvement of melon to improve fruit quality characteristics and postharvest handling. Despite more than 140 transgenic melon field trials in the United States in 1996, there are still no commercial transgenic melon cultivars on the market. This may be a combination of technical or performance
Pediatric Infectious Disease Journal, 1995
Analysis of restriction fragment length polymorphisms is a well-established method of "D... more Analysis of restriction fragment length polymorphisms is a well-established method of "DNA fingerprinting" that has been used to trace the transmission of particular strains of Mycobacterium tuberculosis during investigations of outbreaks. This report describe the use of restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis to investigate two outbreaks of tuberculosis that affected six children who attended two pediatric wards in our hospital. In both outbreaks a history of household exposure to an adult with M. tuberculosis was obtained and suspected tuberculous contacts were identified. We have demonstrated unequivocally the strain relationship among the isolates in all the cases by restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis. These techniques are very useful for performing epidemiologic studies of tuberculosis in children where natural history of tuberculosis infection is different from that in adults in that it is almost always primary infection rather than reactivation.
Pediatric Infectious Disease Journal, 1995
Analysis of restriction fragment length polymorphisms is a well-established method of "D... more Analysis of restriction fragment length polymorphisms is a well-established method of "DNA fingerprinting" that has been used to trace the transmission of particular strains of Mycobacterium tuberculosis during investigations of outbreaks. This report describe the use of restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis to investigate two outbreaks of tuberculosis that affected six children who attended two pediatric wards in our hospital. In both outbreaks a history of household exposure to an adult with M. tuberculosis was obtained and suspected tuberculous contacts were identified. We have demonstrated unequivocally the strain relationship among the isolates in all the cases by restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis. These techniques are very useful for performing epidemiologic studies of tuberculosis in children where natural history of tuberculosis infection is different from that in adults in that it is almost always primary infection rather than reactivation.
Pediatric Infectious Disease Journal, 1995
Analysis of restriction fragment length polymorphisms is a well-established method of "D... more Analysis of restriction fragment length polymorphisms is a well-established method of "DNA fingerprinting" that has been used to trace the transmission of particular strains of Mycobacterium tuberculosis during investigations of outbreaks. This report describe the use of restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis to investigate two outbreaks of tuberculosis that affected six children who attended two pediatric wards in our hospital. In both outbreaks a history of household exposure to an adult with M. tuberculosis was obtained and suspected tuberculous contacts were identified. We have demonstrated unequivocally the strain relationship among the isolates in all the cases by restriction fragment length polymorphisms and arbitrarily primed polymerase chain reaction analysis. These techniques are very useful for performing epidemiologic studies of tuberculosis in children where natural history of tuberculosis infection is different from that in adults in that it is almost always primary infection rather than reactivation.