Esterase Patterns Research Articles

Esterase as an enzymatic signature ofGeodermatophilaceaeadaptability to Sahara desert stones and monuments

To assess esterase profiling of members of Geodermatophilaceae isolated from desert stones and monuments in Tunisia and Egypt. Members of Geodermatophilaceae family isolated from desert stones and monuments in Tunisia and Egypt were characterized by partial 16S rRNA sequences. Twenty-five strains were clustered in three dissimilar groups of the genera Geodermatophilus (12 strains), Blastococcus (5 strains) and Modestobacter (3 strains). Isolates were also screened and typed based on major groups of esterase hydrolytic activity. Their esterase patterns were determined and compared to those of ten reference strains belonging to Geodermatophilaceae family. Strains exhibited a diverse and complex pattern of electrophoretic esterase bands, and 31 haplotypes were obtained for the 35 investigated strains. Esterases produced by members of Geodermatophilaceae family have an optimal activity around 40 degrees C and at pH 8. Esterases from Geodermatophilus strains display a high resistance to thermal inactivation and alkaline pH and retaining 30 and 20% of activity after heating for 20 min at 120 degrees C and at pH 12, respectively, and were completely inactivated after 30 min at 120 degrees C. Enzyme activity has been strongly activated in the presence of Ca(2+)and Mg(2+) ions and moderately by Zn(2+) and was markedly inhibited by Cu(2+) and Co(2+) ions. Geodermatophilaceae isolates share a rich and particular pool of esterase activities that could be directly linked to harsh conditions characterizing their ecological habitat including high level of aridity, temperature, ionic strength and low nutrient availability. Esterase could be considered as enzymatic signature that outlines adaptability of Geodermatophilaceae in arid area.

The electrophoretic patterns of skipjack tuna tissue esterases

As many as twelve bands of esterase activity were observed in the zymograms of homogenized skipjack tissue. With rare exception, the tissues of a single individual show a pattern of related similarity which is clearly evident in the more prominent bands. With the exception of light and dark muscles, each tissue is distinguishable, one from another, either by means of the banding pattern or by the density and rapidity of staining, or both. Some of the variations observed were so clearly similar to variations produced in known genetic systems in other forms as to reasonably postulate that they were the products of the segregation of presumably allelic genes. The usefulness of the techniques for population analysis is evaluated and some future applications are suggested.

Effect of environmental and genetic factors on the stability of pea (Pisum sativum L.) isozyme and DNA markers

Environmental (geographic location, year-to-year effect) and genetic (intravarietal variation) effects on the stability of the isozyme patterns of esterase (EST), acid phosphatase (ACP), alcohol dehydrogenase (ADH), leucine aminopeptidase (LAP), shikimate dehydrogenase (SDH) and glucose-6-phosphate isomerase (PGI) used for pea cultivar genotyping were studied. In addition, selected DNA markers (RAPD, SSR, ISSR, IRAP) were used to study intravarietal genetic homogeneity/variation at a DNA level. Five commercial dry-seed pea (Pisum sativum L.) cultivars Canis, Gotik, Komet, Sonet and Zekon were grown during four years (2001 – 2004) in three locations in the Czech Republic (Šumperk, Čáslav, Uherský Ostroh) that differed in soil and climatic characteristics. Mature dry seeds were used as a standard input sample for analyses. No variation in isozyme spectra was found within particular cultivars between years, locations and fruiting nodes in enzymes providing in general a low polymorphism in pea cultivars (ACP, ADH, LAP, SDH, PGI); similarly, these enzymes also exhibited high stability as related to intravarietal variation. In contrast, EST – highly polymorphic in pea cultivars – showed certain qualitative variation within particular cultivars as related to both environmental and genetic factors. The intravarietal variation detected by selected DNA markers was negligible and mostly quantitative. Possible reasons for the instability/variation of isozyme markers are discussed from the aspect of cultivar genotyping used in pea breeding and seed production.

Estimation of genic similarity within and between Arion hortensis s. 1. and A. intermedius by means of isoelectric focused esterase patterns in hepatopancreas homogenates (Mollusca, Pulmonata: Arionidae)

Estimation of genic similarity within and between Arion hortensis s. 1. and A. intermedius by means of isoelectric focused esterase patterns in hepatopancreas homogenates (Mollusca, Pulmonata: Arionidae)

Differential expression of physiological and biochemical characters of some Indian mangroves towards salt tolerance.

Mangroves are physiologically interesting as potential models for stress tolerance and as sources of alternative ideas about physiological strategies relevant at the ecosystem level. Variation in habitat has great impact on the physiological behavior and biochemical expression level of a particular plant species. Five species of mangroves, growing in saline and fresh water conditions were assessed for their ecological fitness in two different habitats. Assessments were based on some physiological and biochemical parameters measured from the fully exposed mature leaves under saline (15-27 PPT) and non-saline (1.2-2 PPT) conditions. Among the five species considered for investigation Bruguiera gymnorrhiza, Excoecaria agallocha and Phoenix paludosa grow luxuriously in the Sundarbans forest, while the rest two (Heritiera fomes, Xylocarpus granatum) are scanty. A comparative account of photosynthetic efficiency, chlorophyll content, mesophyll and stomatal conductance, specific leaf area, photosynthetic nitrogen use efficiency, total foliar free amino acids and differential expression of some antioxidant isoenzymes in leaf were estimated between the saline and non-saline plants. Elevated assimilation rate coupled with increased chlorophyll content, increased conductance and higher specific leaf area in non-saline condition indicates ability of these mangroves to grow even under minimal substrate salinity. The optimum PAR acquisition for photosynthesis in B. gymnorrhiza, E. agallocha and P. paludosa was higher under salt stress, while the maximum assimilation rate was lower in control plants. The opposite trend occurred in H. fomes and X. granatum, where the peak photosynthesis was lower under non-saline conditions even at a higher irradiance than in the saline forest. The isoform patterns of peroxidase, acid phosphatase and esterase indicated considerable difference in regulation of these enzymes due to salt stress and /or reverse adaptation.

Morphology, cytochemistry and ultra-structure of blood cells in large Indian civet Viverra zibetha (Carnivora, Viverridae)

Viverra zibetha, also known as the large Indian civet, is found from Indochina to southern China. This species is listed as Near Threatened. Blood samples from four adult (two males and two females) large Indian civets in Khao Kheow Open Zoo, Thailand, were prepared for morphological, cytochemical and ultra-structural observation. The red blood cells showed marked anisocytosis, with a mean diameter of 5.0 µm. The cytochemical staining (Sudan black B, peroxidase, α-naphthyl acetate esterase and β-glucuronidase) patterns of leukocytes and haematology were summarised. Eosinophils contained numerous short rod, red refractive granules. Eosinophils lacked sudanophilia and peroxidase activity. Under scanning electron microscopy (SEM), eosinophils showed rod-shaped granular surfaces. Ultra-structurally, these granules contained lamellar components. Basophils had dull grey, round to oval granules. Under SEM, the basophil surface was smooth with pleomorphic granular contours. Ultra-structurally, the basophil granules contained crystalloid components. Neutrophil engulfed red blood cells, and a sac of eosinophil granules was observed under a transmission electron microscope. These results provide more information on morphological, cytochemical and ultra-structural characteristics of blood cells in large Indian civets.

Variability of esterase patterns in adult flies of the saltans species group of Drosophila (subgenus Sophophora)

Esterases are known for their involvement in several physiological processes and high degree of polymorphism, in many organisms. Such polymorphism has been used to characterize species and species groups and to study genetic changes occurred in their evolutionary history. In the present study, the esterase patterns of 19 strains from 10 species representative of the five subgroups of the saltans species group were analyzed using polyacrylamide gel electrophoresis and alpha- and beta- naphthyl acetates as substrates. Fifty-one esterase bands were detected and classified as 31 alpha-esterases, 18 beta-esterases and two alpha/beta-esterases. On the basis of the inhibition patterns using Malathion and eserine sulfate, 34 bands were classified as carboxylesterases, 14 as acethylesterases and three as cholinesterases. Ten gene loci were tentatively established on the basis of data on band position in the gel, substrate preference and inhibition pattern. Twenty bands were species-specific, the remaining being shared by species from the same or different subgroups. Bands detected exclusively in males and bands with a different frequency or degree of expression between sexes were also detected. In the gels prepared for analysis of gene expression in the body parts (head, thorax and abdomen), the degree of expression of the beta-esterases was higher in the thorax, while the alpha-esterases were expressed predominantly in the abdomen and thorax. A global view of the data available at present on the esterases of the species from the saltans group and their degree of polymorphism are presented, as well as the possibility of using some beta-esterases, because of their characteristics in the gels, as markers for species identification.

Sex differences and androgenic regulation of esterases in the house mouse

The distribution of molecular forms of esterases in serum, liver and kidney from NMRI, C57BL/6 and A/J mice and the effect of testosterone propionate on the zymograms were investigated. It was found that the different tissues are specific in the pattern of esterases and that, especially in serum and kidney, the distribution of esterases is highly sex specific. Sex hormones are responsible for this. Administration of testosterone has an effect on the amounts of esterases in both sexes, primarily reducing the normal sex differences.

Miscanthus plants used as an alternative biofuel material: The basic studies on ecology and molecular evolution

Miscanthus Anderss, widely distributed in Asia and Pacific Islands, possesses 20 species. Of which 8 species and 1 variety were recorded in Chinese Mainland; 6 species and 1 variety found in Japan; 5 species and 3 varieties distributed in Taiwan; 3 species documented in the Philippines; and rest of species have been recorded in Jawa, eastern Himalaya, and Sikkim. The plant is a C 4 perennial grass with high productivity of biomass. In the 19th and early 20th centuries in Taiwan, Miscanthus was a very important crop used for forage grass, clothing, and shelter, etc. The relatively high germination, and high yield of biomass made the plant available for people of Taiwan including aboriginal. The taxonomic study of Miscanthus plants was much done by several scientists, and its ecological study has been only taken by the present author since 1972. Chou and his associates paid a great attention to elucidate the mechanism of dominance of Miscanthus vegetation and found that allelopathy plays an important role. In addition, the population biology of Miscanthus taxa by using polyacrylamide gel electrophoreses technique to examine the patterns of peroxidase and esterase among populations (over 100) of Miscanthus in Taiwan were conducted. They also elucidated the phylogenetic relationship among species and varieties in Taiwan. Chou and Ueng proposed an evolutionary trend of Miscanthus species, indicating that the Miscanthus sinensis was assumed to be the origin of Miscanthus Anderss, which evolved to M. sinensis var. formosana, and M. sinensis var. flavidus, and M. sinensis var. transmorrisonensis, and Miscanthus floridulus was thought to be an out group of M. sinensis complex. Moreover, molecular phylogeny was attempted to clarify the population heterogeneity of M. sinensis complex, resulting in a substantial information. It would be available for making hybridization between Miscanthus species and its related species, such as Saccharum (sugar cane) spp. which is a high energy resource plant. European scientists already brought Asian Miscanthus species and bred a new hybrid called Miscanthus × giganteus, which is now being used as a biofuel material in Europe and would be widely used in the world in the near future if fundamental questions, such as fiber transformation to alcohol or other breeding techniques, are answered.

Alterations in biochemical components in mesta plants infected with yellow vein mosaic disease

Yellow vein mosaic disease of mesta (kenaf, Hibiscus cannabinus L.; and roselle, H. sabdariffa L.) is a new entrant to the disease scenario and it is associated with a novel monopartite Begomovirus. Changes in different biochemical parameters in diseased mesta plants were observed as compared to healthy ones. Isozyme pattern and assays of different enzymes, namely catalase, acid phosphatase, peroxidase, esterase, polyphenol oxidase and superoxide dismutase, revealed lower activities of catalase, acid phosphatase and peroxidase enzymes and enhanced activities of esterase, polyphenol oxidase and superoxide dismutase in diseased plants as compared to healthy ones. Due to the infection, chlorophyll content, phenolics and total soluble protein decreased whereas free amino acid, proline and disease-related proteins increased in the host plants. Differential responses of polyacetylene and isoflavone content as well as SDS-PAGE band profiling of total soluble proteins were also observed in plants due to the infection.

Effects of water‐borne copper on the gills and hepatopancreas of Macrobrachium rosenbergii

We focused on elucidating the toxic effects of water-borne copper on the giant freshwater prawn Macrobrachium rosenbergii. After seven days of exposure to copper (Cu(2+) ) at concentrations ranging from 0.01 mg L(-1) to 0.5 mg L(-1) , three isozymes, malate dehydrogenase, alkaline phosphatase and esterase, were analyzed and compared using polyacrylamide electrophoresis (PAGE) and biochemical staining. The results indicated that the electrophoretic patterns of the isozymes showed a copper-concentration-related difference. Low doses of copper stimulated strong expression of the three isozymes. Electrophoretic patterns of malate dehydrogenase and alkaline phosphatase gradually became weaker or even lost as the level of copper increased. In contrast, esterase patterns exhibited an increased molecular heterogeneity at higher copper concentrations. A transmission electron microscope was used to study ultrastructure differences in the gills and hepatopancreas of M. rosenbergii, and the results showed significant structural damage at increased levels of copper compared with the control group. The basement membranes and mitochondira in the gills were seriously damaged, the cuticle electron density distribution was not homogeneous, and an infolded basement membrane, circularized nucleus, disintegrated nuclear membrane, and decreased mitochondria number and size were observed in the gills. Similarly, flowing out of karyoplasms, partly falling microvilli, decreased mitochondrion, partly disappeared mitochondrial cristae, and a thinned matrix were observed in the hepatopancreas. These findings indicate that exposure to elevated copper levels might damage the ultrastructure of the gills and hepatopancreas of M. rosenbergii and might further weaken their normal physical activities. Isozymes were quite sensitive to environmental stress and changes in isozyme elctrophoretic patterns might be effective biomarkers of environmental contamination.

CYTOLGICAL AND ISOZYMES STUDIES OF GARLIC CULTIVATED IN EGYPT.

Generally It has been accepted that the apomictic nature of nature of garlic clones could affect its cytological and genetical features as a result of accumulation of certain somatic mutations. Thus, the aim of this study is to examine some of the cytological (karyotyping, mitotic index and mitotic abnormalities) and isozyme characteristics of five garlic genotypes cultivated in Egypt (Baladi , Chinese , Chinese , 30-4 , Chinese 31-1and Chinese 31-3).Relative chromosome lengths and centromere position of these genotypes revealed insignificant difference in their karyotype formula (5 large , 2 medium from submetacentric pair and one large metacentric pair no. 5). The percentage of mitotic index of Baladi genotype (8.28%) was not very much different from that of Chinese (12.08%) whereas it was significantly lower than those of Chinese 30-4 (15.6%),Chinese 31-1(18.18%)and Chinese 31-3 (16. 8%). Means of total chromosomal abnormalities (including anuepliody, break and stickiness) were remarkably lower in genotypes Baladi (7.64%) and Chinese (9.38%)than those of Chinese 30-4 (11.94%), Chinese 31-3 (11.2%). Statistical analysis revealed that there was a high correlation (0.77) between the mitotic index and the percentage of mitotic chromosome abnormalities. Isozymes [Acid phosphatase, Glutamate Oxaloacetate Transaminase (GOT), Peroxidase and Esterase) banding patterns were qualitatively compared. The banding patterns of esterase (2bands) and GOT (one band) were similar in all five genotypes. As for Pyroxidase, the four genotypes of the Chinese origin had two bands, whereas only one band was shown by the genotype Baladi that was similar in molecular weight to small band of Chinese genotypes. All studies genotypes of acid phosphatase showed one band, which was of a low molecular weight in all except in Chinese genotype where it was a high molecular weight and Chinese 31-1 in which both low and high molecular weight bands were found.

Indonesia

The local rice from Klaten have been released by the Departement of Agriculture in the 2003’s. It was named Rojolele. This is one of variety rices from Indonesian that was used in breeding programme of IRRI. The observation showed that there was morphological variation on Rojolele which grown in Klaten. The aims of this research were to study the Rojolele variation of rice in Klaten, based on their morphological as well as the genetic characters. The cultivars used in this study were: Rojolele from Gledeg, Kadilajo, Karangan, Mrisen, Taji and Trasan. All of the six Rojolele’s rice were planted in Karangan village, Karanganom, Klaten district. The characters used were seed and pollen morphological data, as well as isozymic pattern. The research was done in sub Laboratory of Biology, Central Laboratory of MIPA UNS, using acetolysis method for characterizing the pollen morphology. While the SDS PAGE method was used in studying the isozymic of Peroxidase (PRX) and Esterase (EST) patterns. The data for characterizing the seeds were used: color, shape and pollen morphology were described. Meanwhile the pattern of isozymic patterns were used to analysis the hierarchical cluster, euclidean distance of SPSS 11.5 software was used for all of Rojolele cultivars. Accordingly the quantitatif data which consist long of awn, seed shape and pollen shape were grouped using cluster hierarchical analysis, between group linkage employing the above software. The results showed that based on character of pollen morphology, all of Rojolele cultivars were not different, on the other hand according to seed morphology, specially the long of awn character, Rojolele in Klaten district were separated into 2 groups. First, Rojolele which has a long awn include Gledeg, Karangan and Taji, while Kadilajo, Mrisen and Trasan were grouped in another group which have a short awn. This grouping was supported also by the result of analysis of Peroxidase and Esterase pattern. Rojolele cultivars which have a long awn have 4 bands for Peroxidase isozyme and 4 bands for Esterase isozyme, while Rojolele cultivars which have a short awn have 5 bands for Peroxidase isozyme and 3 bands for Esterase isozyme. It is suggested that the variation of seed morphology especially long of awn may be controlled by the genetic factor (isozyme). Keyword: Oryza sativa, pollen, isozyme, Rojolele, taxonomy.

Esterase enzymes involved in pyrethroid and organophosphate resistance in a Brazilian population of Riphicephallus ( Boophilus) microplus (Acari, Ixodidae)

Esterases are a group of enzymes that are reportedly associated with acaricide resistance in Riphicephallus ( Boophilus) microplus. A comparative analysis was made of the esterase patterns in malathion and deltamethrin-sensitive, tolerant and resistant tick groups, using non-denaturing polyacrylamide gel electrophoresis. Electrophoretical profiles revealed four bands of esterase activity against α-naphthyl acetate; which were dubbed EST-1 to EST-4. The EST-3 and EST-4 were detected in all strains and were classified as carboxylesterases (CaEs). The EST-2, classified as an acetylcholinesterase (AChE), was detected in all groups, but its staining intensity increased from susceptible to resistant groups, indicating an altered production according to the degree of resistance. EST-1, which was also classified as an AChE, was detected exclusively in tolerant and resistant groups to both acaricides, but displayed greater activity in the malathion-resistant group. These data suggest that these AChEs may represent an important detoxification strategy developed to overcome the effects of acaricides.

The pedunculopontine nucleus in developmental disorders of the basal ganglia

The pedunculopontine nucleus (PPN), which is located in the upper brainstem, contains cholinergic and non-cholinergic neurons, and has afferent and efferent connections to the basal ganglia and spinal cord. The PPN is known to be affected in adult-onset basal ganglia diseases, and we speculated that the PPN might be similarly insulted in developmental basal ganglia disorders. We immunohistochemically examined the expression patterns of acetylcholine esterase and tyrosine hydroxylase, markers of acetylcholinergic and catecholaminergic neurons, respectively, in the PPN pars dissipata (PPNd) of controls and patients with bilirubin encephalopathy (BE) and perinatal hypoxic ischemic encephalopathy with localized basal ganglia lesion (HIEbg). Controls showed an age-dependent change in the percentages of acetylcholinergic and catecholaminergic neurons. Three out of six BE cases and three out of six HIEbg cases showed a reduction in the percentage of acetylcholinergic neurons in the PPNd. Additionally, three BE cases demonstrated an increase in the percentage of catecholaminergic neurons. It is likely that the relative proportions of acetylcholinergic and catecholaminergic neurons in the PPN can be altered in developmental basal ganglia disorders.

Studies on pirimicarb resistance mechanisms in Iranian populations of the peach-potato aphid, Myzus persicae

Mechanisms of resistance to pirimicarb were surveyed in Iranian populations of the peach-potato aphid, Myzus persicae. Insecticide bioassays were carried out using topical application on three different populations collected from Karaj and Rasht in the Northern provinces. Results of the bioassays indicated that Rasht and Karaj-S populations were susceptible to pirimicarb. A population collected from the college greenhouse (Karaj-R) was resistant to pirimicarb. LD50 (>100 ng/insect) of pirimicarb was not calculated for the Karaj-R population due to limited solubility of this insecticide. The activity and PAGE patterns of esterase in resistant (Karaj-R) and susceptible populations showed that one mechanism of resistance to pirimicarb was esterase-based resistance. Esterase activity of the Karaj-R population was 3.25-fold higher than the susceptible population (Karaj-S), and one of the two esterase bands with higher activity in the Karaj-R population showed strong susceptibility to pirimicarb. The acetylcholinesterase (AChE) of the Karaj-R population had lower affinity to artificial substrates, acetylthiocholine, propionylthiocholine and butyrylthiocholine, than Rasht and Karaj-S populations. The I50 of pirimicarb for Karaj-R, Karaj-S and Rasht populations was 1.89×10−5 M, 1.37×10−8 M and 1.37×10−8 M, respectively. These results suggest that AChE of the Karaj-R population is insensitive to pirimicarb. Ratios of AChE insensitivity of the Karaj-R population to the Karaj-S population were 1,384.6, 11.8 and 2.7 for pirimicarb, monocrotophos and aldicarb, respectively; however, the ratios were 0.32, 0.15 and 0.10 for carbofuran, propoxure and MTMC, respectively, showing negatively correlated sensitivity to pirimicarb-insensitive AChE.

Qualidade sanitária e fisiológica de sementes de milho submetidas a termoterapia e condicionamento fisiológico

A termoterapia é uma medida de controle tradicionalmente utilizada com sucesso para eliminação de patógenos em sementes de espécies hospedeiras. Trata-se, no entanto, de uma medida que provoca alterações fisiológicas e bioquímicas nas sementes em diferentes intensidades, podendo comprometer o desempenho das mesmas nas condições de cultivo. Objetivou-se com este trabalho avaliar a eficácia da termoterapia no controle de alguns fungos associados a sementes de milho e do condicionamento osmótico, após o tratamento térmico, no sentido de reparar danos nas sementes provocados nestas circunstâncias. Os fungos associados às sementes foram avaliados por meio do método de incubação em substrato de papel com congelamento, e a qualidade fisiológica das sementes pelos testes de germinação, primeira contagem, condutividade elétrica, e padrões eletroforéticos das enzimas esterase (EST), malato desidrogenase (MDH) e álcool desidrogenase (ADH). O tratamento térmico utilizado foi por imersão em água aquecida a 60°C por 5, 10 e 20 minutos. Após o tratamento, uma fração das sementes foi submetida ao condicionamento fisiológico em rolo de papel embebido em solução de PEG 6000 a -1,2 MPa. Todos os tratamentos térmicos reduziram ou eliminaram Acremonium strictum das sementes. A incidência de Fusarium verticillioides foi reduzida significativamente pelo tratamento térmico nos períodos de 10 e 20 minutos. À medida que se aumentou o tempo de exposição ao tratamento térmico, houve aumento dos valores de condutividade elétrica e redução significativa da primeira contagem e germinação das sementes. O tratamento térmico durante 20 minutos alterou os padrões eletroforéticos das enzimas esterase e malato desidrogenase. O condicionamento fisiológico das sementes não foi capaz de reverter os danos causados pela termoterapia.

Development of silverleaf assay, protein and nucleic acid-based diagnostic techniques for the quick and reliable detection and monitoring of biotype B of the whitefly, Bemisia tabaci (Gennadius)

The aim of this study was to develop and optimize silverleaf bioassay, esterase analysis and PCR-based techniques to distinguish quickly and reliably biotype B of the whitefly, Bemisia tabaci (Gennadius), from Indian indigenous biotypes. Zucchini and squash readily develop silverleaf symptoms upon feeding by the B biotype, but they are not readily available in Indian markets. A local pumpkin variety 'Big' was, therefore, used in silverleaf assay, which developed symptoms similar to those on zucchini and squash and can be used reliably to detect B biotype. Analysis of non-specific esterases of B and the indigenous biotypes indicated both quantitative and qualitative differences in esterase patterns. Two high molecular weight bands were unique to B biotype and they occurred in abundance. These esterases were used to develop quick and field-based novel detection methods for differentiating B from the indigenous biotypes. Development of these simple and cost-effective protocols has wider application as they can be potentially used to identify other agricultural pests. Mitochondrial cytochrome oxidase I gene sequences and randomly amplified polymorphic DNA (RAPD) polymorphisms, generated using the primer OpB11, were also found useful for detecting B. tabaci biotypes. A B biotype-specific RAPD band of 800 bp was sequenced, which was used to a develop sequence characterized amplified region (SCAR) marker. The SCAR marker involved the development of B biotype-specific primers that amplified 550 bp PCR products only from B biotype genomic DNA. Silverleaf assay, esterases, RAPDs or a SCAR marker were used in combination to analyse whitefly samples collected from selected locations in India, and it was found that any of these techniques can be used singly or in combination to detect B biotype reliably. The B biotype was found in southern parts of India but not in the north in 2004-06.

Expressão diferencial de isoenzimas durante o processo de germinação de sementes de arroz em grandes profundidades de semeadura

O processo de germinação se constitui num complexo e ordenado conjunto de eventos fisiológicos e bioquímicos em que a semente é submetida logo após iniciar a absorção de água. A retomada do crescimento do embrião por causa da absorção de água envolve a reativação de muitas enzimas já presentes nas sementes e a sínteses de outras que irão hidrolisar as sustâncias de reserva, fornecer poder oxidante, energia, entre outras, para a germinação. A emergência das plântulas nas monocotiledôneas depende, principalmente, da profundidade de semeadura, e de muitos outros fatores tais como atributos genéticos e vigor das sementes, sendo que o embrião é nutrido de forma exclusiva, pelas reservas da semente. No presente trabalho, os padrões isoenzimáticos de Esterase (EST), Fosfatase Acida (ACP), Malato Deshidrogenase (MDH), Álcool Deshidrogenase (ADH) e Glutamato Oxalacetato Transaminase (GOT) de 34 ecótipos de arroz vermelho e 5 cultivares comerciais foram analisados durante o processo de germinação a 20 cm de profundidade com o objetivo de identificar variações de expressão diferencial nos sistemas isoenzimáticos analisados. Os cinco sistemas isoenzimáticos analisados apresentaram variações na expressão enzimática, principalmente quando comparados os padrões observados em semente seca e em plântulas em desenvolvimento. Dos resultados obtidos conclui-se que, há um diferencial de expressão nos genes que comandam a expressão das isoenzimas Esterase (EST), Fosfatase Ácida (ACP), Malato Deshidrogenase (MDH), Álcool Deshidrogenase (MDH) e Glutamato Oxalacetato Transaminase (GOT), nos processos de germinação de sementes de arroz.

Immunohistochemical changes in methyl-ester distribution of homogalacturonan and side chain composition of rhamnogalacturonan I as possible components of basal resistance in tomato inoculated with Ralstonia solanacearum

The composition and structure of pectic cell wall polysaccharides of stem sections were investigated in healthy and Ralstonia solanacearum-inoculated tomato genotypes L390 and Hawaii 7996, susceptible and resistant to bacterial wilt, respectively, by immunohistochemical analysis. Constitutive differences between genotypes manifested in methyl-ester distribution of homogalacturonan (HG), arabinan and galactan side chain composition of rhamnogalacturonan I (RG I) and arabinogalactan-protein (AGP) in the xylem parenchyma and in vessel cell walls. After inoculation increased labeling was observed with all the antibodies (JIM5, JIM7, LM2, LM5, LM6, LM7) specific for HG, RG I and AGP epitopes, in the xylem parenchyma and around xylem vessels of stem sections of L390, but not of Hawaii 7996. Also vessel cell walls were stronger stained after inoculation in L390, particularly for the non-blockwise de-esterification of HG, possibly indicating for the first time the non-blockwise action pattern of bacterial pectin methyl esterase. In genotype Hawaii 7996 a reaction to inoculation was observed only in vessel walls, with a significantly increased number of stained vessels—five- and nine-fold for arabinan and galactan epitopes of RG I, respectively. Differences in xylem cell wall structure may play a role as a constitutive resistance mechanism in the multigenic resistance of tomato against bacterial wilt, while changes after inoculation may contribute to induced basal resistance on cell wall level.