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PubMed2004

Transcriptional immune responses by honey bee larvae during invasion by the bacterial pathogen, Paenibacillus larvae.

Honey bee larvae are highly susceptible to the bacterial pathogen Paenibacillus larvae only during the first instar of larval development. Transcript levels were measured for genes encoding two antimicrobial peptides, abaecin and defensin, as well as for two candidates in the immune response cascade (PGRP-LD and masquerade) in control larvae and larvae exposed to the pathogen. Transcripts for all four are present throughout development. This suggests that other physiological or dietary factors may better explain the age-based change in vulnerability to this pathogen. One of these genes, abaecin, shows significant up-regulation 24 h following oral inoculation with P. larvae, precisely when the bacterium surmounts the midgut epithelia of bees. Expression of both antimicrobial peptides varied by 1000-fold across different nestmate bees, indicating an allelic component to their expression. The implications of these results for current hypotheses related to disease tolerance in social insects are discussed, along with implications for breeding bees resistant to this important disease.

Animals↗
PubMed1990

Radioimmunoassay for the quantitative determination of galanthamine.

A radioimmunoassay for the quantitation of pmol amounts of the therapeutically important Amaryllidaceae alkaloid, galanthamine, has been developed. The antiserum was raised against a conjugate of galanthamine-2-O-hemisuccinate-bovine serum albumin. The measuring range of the assay extends from 0.5 to 100 ng of galanthamine, and as little as 3.5 pmol may be detected. The antiserum is highly specific for galanthamine, showing practically no cross reactivity with different representatives of the most frequently occurring types of alkaloidal structures in Amaryllidaceae. This assay enables a rapid, sensitive and precise quantitation of galanthamine in unpurified plant extracts. The galanthamine concentration in bulbs of several Leucojum aestivum plants and the distribution of galanthamine in some Amaryllidaceae genera of South African origin have been investigated. Preliminary experiments indicate that the galanthamine-specific radioimmunoassay can be a useful tool in medicinal plant breeding as well as in tissue and cell culture studies.

Animals↗
PubMed1996

Half tetrad analysis in alfalfa using multiple restriction fragment length polymorphism markers.

A maximum likelihood approach of half tetrad analysis (HTA) based on multiple restriction fragment length polymorphism (RFLP) markers was developed. This procedure estimates the relative frequencies of 2n gametes produced by mechanisms genetically equivalent to first division restitution (FDR) or second division restitution and simultaneously locates the centromere within a linkage group of RFLP marker loci. The method was applied to the diploid alfalfa clone PG-F9 (2n = 2x = 16) previously selected because of its high frequency of 2n egg production. HTA was based on four RFLP loci for which PG-F9 was heterozygous with codominant alleles that were absent in the tetraploid tester. Models including three linked and one unlinked RFLP loci were developed and tested. Results of the HTA showed that PG-F9 produced 6% FDR and 94% second division restitution 2n eggs. Information from a marker locus belonging to one linkage group was used to more precisely locate the centromere on a different linkage group. HTA, together with previous cytological analysis, indicated that in PG-F9, FDR 2n eggs are likely produced by diplospory, a mechanism common among apomictic species. The occurrence of FDR 2n eggs in plant species and their importance for crop evolution and breeding is discussed together with the potential applicability of multilocus HTA in the study of reproductive mutants.

Centromere↗
PubMed2003

Increased fibronectin deposition in embryonic hearts of retinol-binding protein-null mice.

Precise regulation of retinoid levels is critical for normal heart development. Retinol-binding protein (RBP), an extracellular retinol transporter, is strongly secreted by cardiogenic endoderm. This study addresses whether RBP gene ablation affects heart development. Despite exhibiting an >85% decrease in serum retinol, adult RBP-null mice are viable, breed, and have normal vision when maintained on a vitamin A-sufficient diet. Comparison of RBP-null with wild-type (WT) hearts from embryos at day 9.0 (E9.0) through E12.5 revealed an RBP-null phenotype similar to that of other retinoid-deficient models. At an early stage, RBP-null hearts display retarded trabecular development, which recovers by E9.5. This is accompanied at E9.5 and E10.5 by precocious differentiation of subepicardial cardiac myocytes. Most remarkably, RBP-null hearts display augmented deposition of fibronectin protein in the cardiac jelly at E9.0 through E10.5 and in the outflow tract at E12.5. This phenomenon, which was detected by immunohistochemistry and Western blotting without increased fibronectin transcript levels, is accompanied by increased numbers of mesenchymal cells in the outflow tract but not in the atrioventricular canal. RBP-null cardiac myocytes, especially in the subepicardial layer, display increased cell proliferation. This phenotype may present a model of subclinical retinoid insufficiency characterized by alteration of an extracellular matrix component and altered cellular differentiation and proliferation, changes that may have functional consequences for adult cardiac function. This murine model may have relevance to fetal development in human populations with inadequate retinoid intake.

Animals↗
PubMed1989

Susceptibility and resistance genes to insulin-dependent diabetes mellitus in the BB rat.

Insulin-dependent diabetes mellitus (IDDM, type I) is an autoimmune disorder exhibiting a strong association with particular haplotypes of the major histocompatibility complex (MHC). We have previously shown that the u haplotype of the rat MHC (RT1) is absolutely required for expression of IDDM in the BB rat model of the disease. To define the precise regions of the RT1 contributing to disease occurrence and to address the mechanism by which the associated haplotype participates in disease pathogenesis, we have transferred recombinant haplotypes bearing the IDDM-associated MHC in defined regions onto the BB rat genetic background. In this report, we present data from two breeding studies utilizing the r8 haplotype (RT1AaBuDuEuCu) that demonstrate that (1) the RT1A locus is not involved in the disease association, (2) the MHC genes determining disease susceptibility are not unique to the BB rat, and (3) IDDM resistance genes are found outside the MHC. We also present evidence that the immunoregulatory defect characteristic of BB rats enhances the incidence of IDDM although it is not absolutely required for disease expression. We were able to track the transmission of the recombinant haplotypes in diabetic progeny using a combination of monospecific alloantisera and restriction fragment length polymorphism analysis using locus-specific MHC gene probes.

Animals↗
PubMed2006

Allelic configuration and polysomic inheritance of highly variable microsatellites in tetraploid gynodioecious Thymus praecox agg.

Polyploidy plays a pivotal role in plant evolution. However, polyploids with polysomic inheritance have hitherto been severely underrepresented in plant population genetic studies, mainly due to a lack of appropriate molecular genetic markers. Here we report the establishment and experimental validation of six fully informative microsatellite markers in tetraploid gynodioecious Thymus praecox agg. Sequence data of 150 microsatellite alleles and their flanking regions revealed high variation, which may be characteristic for polyploids with a reticulate evolutionary history. Understanding the patterns of mutation (indels and substitutions) in microsatellite flanking-sequences was a prerequisite for the development of co-dominant markers for fragment analyses. Allelic segregation patterns among progeny arrays from ten test crosses revealed tetrasomic inheritance in T. praecox agg. No evidence of frequent double reduction was detected. Polymerase chain reaction (PCR) based dosage effects allowed for precise assignment of allelic configuration at all six microsatellite loci. The quantification of allele copy numbers in PCR was verified by comparisons of observed and expected gametic allele frequencies and heterozygosities in test crosses. Our study illustrates how PCR based markers can provide reliable estimates of heterozygosity and, thus, powerful tools for breeding system and population genetic analyses in polyploid organisms.

Alleles↗
PubMed1999

Canine urate urolithiasis. Etiopathogenesis, diagnosis, and management.

Etiopathologic factors predisposing to urate lithogenesis in Dalmatian and non-Dalmatian dogs represent diverse pathologic and/or physiologic processes involving purine nucleotide and ammonia synthesis, biodegradation, and excretion. Predisposing factors for urate urolith formation include hyperuricemia, hyperammonemia, hyperuricosuria, hyperammonuria, aciduria, and genetic predisposition. Medical therapy of dogs forming urate uroliths should be directed at modifying these predisposing factors through dietary modification, administration of allopurinol, and/or surgical correction of portovascular anomalies if present. The precise mechanisms resulting in urate urolith formation in dogs have not been determined.

Animals↗
PubMed1999

Subgroup-A Rous sarcoma virus-induced growth stimulation of chick embryos infected via the chorioallantoic membrane.

Chicks that hatch from eggs containing group specific antigen (gs antigen) of lymphoid leukosis virus (LLV) subgroups, grow poorly. In our laboratory for more precise identification of LLV-of subgroup A (LLV-A) resistant and susceptible genotypes by progeny testing, the chorioallantoic membrane (CAM) assay in complemented by liver tumour (LT) assay, wherein Rous sarcoma virus (RSV) of subgroup A (homologous to LLV-A) was used. The present study was conducted in a light breed (White Leghorn) and also in a heavy breed (Rhode Island Red) to ascertain the effect of infection on embryonic growth by RSV subgroup A. Mean relative body weight (rbw) of infected LT negative chicks of either breed exceeded the control highly significantly (P < 0.01) by 2%. However, neither the dose of virus inoculated per embryo, nor egg size influenced the relative body weight of day old chicks (P > 0.05). No difference in relative body weight of LT positive and control chicks was observed.

Allantois↗
PubMed1987

Statement on the nomenclature of dog C4 allotypes.

As a collaborative work of three laboratories the polymorphism of the canine fourth complement component (C4) was studied in a total of 131 unrelated dogs from different breeds and mongrels. Using high voltage electrophoresis followed by an immunoblotting technique, we detected eight distinct variants. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of canine C4 showed an additional heterogeneity of the alpha and gamma chains which resulted in a total of 11 variants in the population studied. So that more precise information concerning the respective C4 allotypes will be available, a nomenclature is proposed designating not only the migration pattern of the C4 variants in agarose gels but also the heterogeneity of the C4 chains observed in SDS-PAGE.

Alleles↗
PubMed2005

Detection of quantitative trait loci influencing conformation traits and calving ease in Holstein-Friesian cattle.

An extension of our previous genome scan of a North American Holstein-Friesian population was conducted to identify quantitative trait loci (QTL) affecting conformation traits. Resource families consisted of 1404 sons of 10 elite sires. Genome coverage was estimated to be 2713.5 cM (90%) for 406 markers using a granddaughter design. Regression interval mapping was used to detect QTL affecting 22 conformation traits, including body, udder, feet and legs, and dairy conformation as well as calving ease. Analysis of the families jointly identified 41 chromosome-wise significant QTL influencing conformation traits and 3 significant QTL influencing calving ease on 20 chromosomes. The false discovery rate method was used to account for multiple testing and 3/4 of the suggestive and 5/6 of significant QTL should be real effects. Fourteen of the 44 QTL were significant at the genome-wise level. Comparison of these results with other published reports identifies common QTL affecting conformation traits. Regions on 10 chromosomes appear to affect multiple traits, including conformation, milk production, and somatic cell score, within these particular US Holstein families. Additional work is needed to determine the precise locations of the QTL and select positional candidate genes influencing these traits.

Animals↗
PubMed2003

Oral cancer: reviewing the present understanding of its molecular mechanism and exploring the future directions for its effective management.

The present review aims to analyze the information available regarding the molecular mechanisms of Oral Carcinogenesis and explore the future directions where the field of Cancer Biology is venturing. Oncologists have excellently followed the proverb "Necessity is the mother of Invention". The desire to be more precise and comprehensive in their studies has led to the invention of some of the most innovative techniques like laser capture microdissection, comparative genomic hybridization, microarrays, and protein chips etc. Various Biotech companies and Cancer Institutes are on a hunt for anti-cancer drugs and molecular markers for cancers. These revolutionary approaches and the new breed of Oncologists have made the field very exciting and have generated the hope that finally the war against cancer would be won. In the end it is urged that the lead taken in other cancers like colon, breast, leukemia will be emulated in oral cancer. This is expected to provide a molecular blueprint for HNSCC, thus helping to identify suitable markers for the early detection of pre-neoplastic lesions, as well as novel targets for its pharmacological intervention.

Carcinoma, Squamous Cell↗
PubMed2004

[Description of an experimental model of hepatorenal syndrome in Wistar rats].

UNLABELLED: In spite of many years of experimental and clinical studies, it failed to discover precise pathomechanisms leading from hepatic damage to functional renal failure in hepatorenal syndrome (HRS). There are few reported animal models of hrs, among them a rat model induced by galactosamine (Ga1N). In this model renal failure develops typically after hepatic damage in male Sprague-Dawley rats. In our study we tried to test, whether other breeds develop typical HRS. MATERIAL AND METHODS: We used male Wistar rats to achieve acute liver and renal failure by intraperitoneal injection of Ga1N. Liver failure developed with significant increase in serum concentration of bilirubin, AST, ALT; ammonia and massive necrosis of hepatocytes. Nevertheless, we did not achieve increase of serum creatinine and urea typical for acute renal failure. CONCLUSIONS: We concluded that only some of rat breeds develop typical hrs, maybe because of some congenital, genetic predispositions.

Alanine Transaminase↗
PubMed2000

Aortic endothelial cell von Willebrand factor content, and circulating plasminogen activator inhibitor-1 are increased, but expression of endothelial leukocyte adhesion molecules is unchanged in insulin-dependent diabetic BB rats.

Endothelial cell injury has been implicated in the increased incidence of vascular disease associated with diabetes mellitus. In diabetic humans, elevated plasma von Willebrand Factor (vWF) has been interpreted as an indication of endothelial damage. In contrast, in an animal model of inherited insulin-dependent diabetes, the bio-breeding (BB) rat, plasma vWF levels did not differ from those in age-matched control rats during the first 7 months of diabetes although morphological evidence of mild aortic endothelial alteration or injury was observed. In the present study efforts have been made to define the endothelial alterations in BB diabetic rats compared to controls more precisely over this time period. Thus, adhesion molecules: intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1(VCAM-1) were evaluated by in situ immunohistochemistry, vWF content was determined by biochemical analysis of aortic extracts and by quantitative immunohistochemistry, plasma vWF levels were measured by ELISA and vWF mRNA by RNAse protection assay. Neither age nor diabetic state significantly affected either the expression of adhesion molecules, or the levels of circulating vWF. Endothelial vWF content was significantly increased in the diabetic vessels, as observed by both approaches but the vWF mRNA content was not different from that in control vessels. Plasma plasminogen activator inhibitor (PAI-1) activity was significantly increased in diabetic animals. In conclusion, endothelial alterations in BB rats associated with diabetes, together with the raised plasma PAI-1 levels, promote the thrombogenic potential of the vessel wall, and are consistent with an increased risk for vascular disease.

Analysis of Variance↗
PubMed1986

Estimation of the true additive genetic variance sigma ki = 1 d2i in the presence of linkage disequilibrium.

Accurate estimates of the true additive genetic variance (sigma ki = 1 d2i) of a cross between two pure breeding varieties can be obtained from the additive genetic components of the first three ranks (D1, D2 and D3) when the latter are biased by the presence of linkage. Additive genetic variances of the lower ranks are directly equatable with sigma ki = 1 d2i because they incur minimal bias even when the predominating linkages are strong. More precise estimates of sigma ki = 1 d2i are however obtainable from the asymptotic regression analysis or a weighted least squares analysis. Estimates of sigma ki = 1 d2i when obtained from 784 hierarchically derived F7 families of the V2 X V12 cross of Nicotiana rustica were observed to be considerably larger than the additive genetic variance displayed by the F13 inbreds of the same cross for all the characters that showed significant excess of repulsion linkages. These results lend support to our commonly held view that the prediction procedures generally underestimate the probability of successful recovery of superior recombinant inbreds.

Analysis of Variance↗
PubMed2005

Water quality and breeding habitats of anopheline mosquito in northwestern Thailand.

Malaria transmission is dependent upon many hydrology-driven ecological factors that directly affect the vectorial competence, including the presence of suitable habitats for the development of anopheline larvae. Larval habitats were identified and characterized at three malaria endemic villages (Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau) in Mae Sot district, Tak Province, in northwestern Thailand between July 2002 and June 2003. The Global Positioning System (GPS) was used to provide precise locational data for the spatial distribution of anopheline mosquito larvae and their habitats. Ten habitat categories were identified. Eighteen adult Anopheles species were identified from larvae in all the surveyed habitats. An. minimus was the most common species throughout the year. The relationship between eight abiotic variables (temperature, hardness, carbon dioxide, dissolved oxygen, nitrate, phosphate, silica and pH) and the abundance of four major species of malaria vectors (An. (Cel.) dirus, An. (Cel.) minimus, An. (Cel.) maculatus, and An. (Cel.) sawadwongporni), and six species of non-vectors (An. (Cel.) kochi, An. (Cel.) jamesii, An. (Ano.) peditaeniatus, An. (Ano.) barbirostris, An. (Ano.) campestris, and An (Cel.) vagus) larvae was investigated. The results from the multiple regression models suggest that hardness, water temperature and carbon dioxide are the best predictor variables associated with the abundance of An. minimus larvae (p < 0.001); water pH for An. dirus larvae (p < 0.001); temperature and pH for An. kochi larvae (p < 0.01); temperature and silica concentration for An. jamesii larvae (p < 0.001); dissolved oxygen and silica concentration for An. campestris larvae (p < 0.001); and pH and silica concentration for An. vagus larvae (p < 0.001). We could not identify key environmental variables for An. maculatus, An. sawadwongporni, An. peditaeniatus, and An. barbirostris.

Animals↗
PubMed2006

LC-APCI-MS method for detection and analysis of tryptanthrin, indigo, and indirubin in daqingye and banlangen.

A rapid, selective, and sensitive LC-APCI-MS method is developed in this study for detecting and analyzing tryptanthrin, indigo, and indirubin in daqingye and banlangen, which are, respectively, the leaves and roots of Isatis indigotica and Strobilanthes cusia in traditional Chinese medicine. The detection of the three active components is linear in concentrations ranging from 100 to 1500 ng/mL, the squared correlation coefficient is higher than 0.996, the precision as measured by the relative standard deviation is no larger than 9.5%, and the recovery is greater than 86.6%. The analysis of the 21 banlangen samples led to considerably different conclusions on the contents of tryptanthrin, indigo, and indirubin in fresh leaves versus those in dried leaves. These results should shed some light on future plant selection and breeding. Compared with the traditional TLC and HPLC-UV methods, the new LC-APCI-MS approach has proven to be an optimal tool for detecting and analyzing the three marker compounds in the Chinese herbal medicines of daqingye and banlangen.

Calibration↗
PubMed2004

A major QTL conditioning salt tolerance in S-100 soybean and descendent cultivars.

Deployment of salt tolerant cultivars is an effective approach to minimize yield loss in a saline soil. In soybean, Glycine max (L.) Merr., substantial genetic variation exists for salt response. However, breeding for salt tolerance is hampered because no economically viable screening method has been developed for practical breeding. To facilitate the development of an effective screening method for salt tolerance in soybean, the present study was conducted to determine the heritability of salt tolerance and to identify associated quantitative trait loci (QTL). F2:5 lines from the cross of 'S-100' (salt tolerant) x 'Tokyo' (salt sensitive) were evaluated in a saline field in Hyde County, N.C., USA, in 1999 and in a greenhouse located in Raleigh, N.C., USA, in 2001. S-100 and Tokyo are ancestors of popular soybean cultivars released for the southern USA. The visual salt tolerance ratings of the F2:5 lines ranged from 0 (complete death) to 5 (normal healthy appearance). The entry-mean heritability for salt tolerance was 0.85, 0.48, and 0.57 in the field (four replications), greenhouse (two replications), and combined environments, respectively. The genotypic correlation between field and greenhouse ratings was 0.55, indicating reasonably good agreement between the two screening environments. To identify QTL associated with salt tolerance, each line was characterized with RFLP markers and an initial QTL single-factor analysis was completed. These results were used to identify genomic regions associated with the trait and to saturate the selected genomic regions with SSR markers to improve mapping precision. Subsequently, a major QTL for salt tolerance was discovered near the Sat_091 SSR marker on linkage group (LG) N, accounting for 41, 60, and 79% of the total genetic variation for salt tolerance in the field, greenhouse, and combined environments, respectively. The QTL allele associated with tolerance was derived from S-100. Pedigree tracking was used to examine the association between the salt tolerance QTL and flanking SSR marker alleles in U.S. cultivars descended from S-100 or Tokyo through 60 years of breeding. The presence of alleles from S-100 at the Sat_091 and Satt237 marker loci was always associated with salt tolerance in descendants. Alleles from Tokyo for these same markers were generally associated with salt sensitivity in descendent cultivars. The strong relationship between the SSR marker alleles and salt tolerance suggests that these markers could be used for marker-assisted selection in commercial breeding.

Adaptation, Physiological↗
PubMed1996

[The determination of von Willebrand factor activity in the plasma of dogs. 1. Experimental evaluation and methods].

Using a new aggregometer, the plasma activity of von Willebrand factor (vWF) in dogs was measured. The method is described. It has the advantage of being more precisely for the diagnosis of von Willebrand's disease than the determination of von Willebrand antigen (vWF: Ag) by using an ELISA. With the method described reproducible and reliable result can be obtained.

Animals↗