Estimation of the Distribution of a Genetically Determined Enzyme Polymorphism by a Stochastical Outside Criterion

The remaining cholinesterase activity after incubation with paraoxon (as an indicator of the activity of human serumparaoxonase) shows a distribution with three clusters which could be explained, after an investigation of families, by a simple two-allele-model. A Stochastical outside criterion is given by the constellations of the values within the families. By modification of an iteration method described by FANGMEYER (1964) it is possible to estimate the distributions and frequencies of the three groups. A simulation study shows that the combination of the used method with the pure cluster analysis is advantageous.     

Comparison of the anti-scorbutic activity of L-ascorbic acid and Ester C in the non-ascorbate synthesizing Osteogenic Disorder Shionogi (ODS) rat

The Osteogenic Disorder Shionogi (ODS) rat, Clea Inc., Tokyo, Japan lacks the ability to synthesize L-ascorbic acid (AA). As with man, monkey and the guinea pig, this rat lacks L-gulonolactone oxidase necessary for the synthesis of AA from glucose. This study shows this animal to be an alternative to the guinea pig in AA studies. The anti-scorbutic potency of Ester C (EC), a calcium ascorbate and calcium threonate mixture, was compared with an AA dose of equal ascorbate activity equivalents (AAE) for anti-scorbutic activity in the ODS rat. The minimal anti-scorbutic dose of EC was determined to be 0.44 mg/kg/day (AAE), while an AA dose of 0.51 mg/kg/day (AAE) was not anti-scorbutic in a 24 day study. At 24 days EC rats gained 125% of initial body weight (BW) and the AA rats only 45% BW. Scorbutic signs at 24 days were scored on a 0 (min) to 3 (max) scale. The EC/AA ratio scores were: hemorrhage 0/1.4, behavior change 0/2.0, piloerection 0/2.2, mobility 0.4/2.2, dysbasia 0.6/2.8 and ataxia 0.4/1.0. Pearson's correlation coefficient for BW versus AAE was r = .34 for the AA group and r = .90 for the EC group. The morbidity index for EC was 0/5 and for the AA group 2/5. The AAE dose of AA which was 16% higher/day than the EC AAE dose was not anti-scorbutic, while the EC dose was anti-scorbutic. EC rats had 3.5X greater weight gain, a sensitive indicator of scurvy, than the AA rats. EC rats had 3-4 times less, if any, scorbutic signs than AA rats. The results clearly show that, based on ascorbate activity equivalents, EC has more available ascorbate activity/potency than AA. The mechanism of this increased potency is believed to be due to the facilitated transport of AAE into the cell by the threonate (a normal in vivo metabolite of AA) present in the EC product. In addition, previous studies have shown EC (AAE) to be higher in plasma and excreted less rapidly than the AAE derived from AA administered orally.     

Haplotype distribution of the human phenylalanine hydroxylase locus in Scotland and Switzerland.

RFLP haplotypes at the phenylalanine hydroxylase (PAH) locus were determined in 45 nuclear Caucasian families from Switzerland and Scotland. The RFLPs at the PAH locus are highly informative, and prenatal diagnosis is possible in 85% of the families studied. The data were combined with the profiles previously observed in the Danish population, in order to study the variation in RFLP haplotype distribution among European populations. A total of 22 different haplotypes were observed in Denmark, Switzerland, and Scotland. Fifteen and 19 haplotypes are associated with the normal (non-PKU) and with the mutant chromosomes, respectively. The haplotype distribution and the allele frequency of normal chromosomes remain constant between Denmark, Switzerland, and Scotland. However, both the haplotype distribution and allele frequencies of mutant chromosomes show significant variation between the three countries. Our results suggest there may be additional mutations in the PAH gene that cause PKU.     

Biochemical genetic analysis of pyrimidine biosynthesis in mammalian cells: I. Isolation of a mutant defective in the early steps of de novo pyrimidine synthesis.

The isolation and characterization of a new mutant of Chinese hamster ovary cells is described. This mutant, Urd-A, shows an absolute requirement for exogenously added pyrimidines for growth. Complementation analysis indicates that the lesion in this mutant is recessive. Revertants can be isolated at frequencies suggesting that it is a single gene alteration. Biochemical analysis of cell-free extracts of CHO-K1 (Urd+) and Urd-A revealed that Urd-A possesses no more than 10% of wild-type levels of carbamyl phosphate synthetase (EC 2.7.2.9) activity, no more than 1% of wild-type levels of aspartate transcarbamylase (EC 1.2.3.2) activity, and undetectable levels of dihydroorotase (EC 3.5.2.3) activity. Thus, this mutant appears simultaneously to possess marked or complete deficiencies in the activities of the first three enzymes of pyrimidine biosynthesis. Activities of the other enzymes of the pathway appear normal. The use of this mutant for biochemical-genetic studies of pyrimidine biosynthesis is discussed.     

Coagulation factor XIII: A useful polymorphic genetic marker

Summary The plasmas of two groups of subjects were examined for blood coagulation Factor XIII-A (FXIII-A, F13A) by electrophoresis in agarose using a Tris-EDTA-borate buffer to separate the common variants, F13A^*1, F13A^*2, and F13A^*3. Dimeric subunits were visualized in UV light as monodansyl cadaverine bound to casein at the position of the transglutaminase activity representing F13A. One test group consisted of 307 members of three large Caucasian families. The other consisted of 148 consecutive patients whose plasmas had been sent to the clinical laboratory for determination of prothrombin time. Segregation analysis and father-to-son transmission confirmed that F13A is inherited as an autosomal co-dominant trait. The allelic frequencies in the random sample were F13A^*1=0.82 and F13A^*2=0.18. This sample included both blacks and whites, and the gene frequencies were not significantly different in the two races. The gene frequencies among the unrelated spouses of the three white families were A^*1=0.75, A^*2=0.24, A^*3=0.01. Genetic equilibrium was present in both groups.The degree of polymorphism, the availability of blood, the ease of assessment, the absence of selective pressure, and the uniformity of gene frequencies in two major American ethnic groups make F13A a very useful marker for linkage studies and paternity testing. F13A has been provisionally assigned to chromosome 6. Linkage analysis of our family data did not provide evidence of linkage to two chromosome 6 markers, properdin factor B (BF) and glyoxalase 1 (GLO). The highest lod score (Z) was between F13A and the Kidd (Jk) blood group (Z=0.68 at -0.24).     

瓣状甲的类型、分布与遗传方式 --对陕西周至县某村的调查

瓣状甲是存在于我国北方许多汉族人群中的一种性状,其表现为小趾趾甲分瓣。我们通过对陕西省周至县某自然村的入户调查发现,瓣状甲的频率为79.17%,其中男性为81.48%,女性为76.67%,性别分布无统计学差异(χ2=1.09,P=0.295)。瓣状甲可为单侧或双侧发生,男性和女性的单、双侧瓣状甲频率无统计学差异(χ2=2.94,P=0.23)。13个年龄组间瓣状甲的频率差异有统计学意义。对2个完整的三代家系和51个核心家系的系谱分析,发现瓣状甲的遗传特点与常染色体单基因显性性状一致。因此,我们认为,瓣状甲是一种单基因显性性状,具有不同的表现类型,既可单侧发生,亦可双侧发生,其分布无性别差异,但有年龄差异。     

Risk stratification by residual enzyme activity after newborn screening for medium-chain acyl-CoA dehyrogenase deficiency: Data from a cohort study

ABSTRACT: BACKGROUND: Since the introduction of medium-chain acyl coenzyme A dehydrogenase (MCAD) deficiency in population newborn bloodspot screening (NBS) programs, subjects have been identified with variant ACADM (gene encoding MCAD enzyme) genotypes that have never been identified in clinically ascertained patients. It could be hypothesised that residual MCAD enzyme activity can contribute in risk stratification of subjects with variant ACADM genotypes. METHODS: We performed a retrospective cohort study of all patients identified upon population NBS for MCAD deficiency in the Netherlands between 2007-2010. Clinical, molecular, and enzymatic data were integrated. RESULTS: Eighty-four patients from 76 families were identified. Twenty-two percent of the subjects had a variant ACADM genotype. In patients with classical ACADM genotypes, residual MCAD enzyme activity was significantly lower (median 0%, range 0-8%) when compared to subjects with variant ACADM genotypes (range 0-63%; 4 cases with 0%, remainder 20-63%). Patients with (fatal) neonatal presentations before diagnosis displayed residual MCAD enzyme activities <1%. After diagnosis and initiation of treatment, residual MCAD enzyme activities <10% were associated with an increased risk of hypoglycaemia and carnitine supplementation. The prevalence of MCAD deficiency upon screening was 1/8,750 (95% CI 1/7,210-1/11,130). CONCLUSIONS: Determination of residual MCAD enzyme activity improves our understanding of variant ACADM genotypes and may contribute to risk stratification. Subjects with variant ACADM genotypes and residual MCAD enzyme activities <10% should be considered to have the same risks as patients with classical ACADM genotypes. Parental instructions and an emergency regimen will remain principles of the treatment in any type of MCAD deficiency, as the effect of intercurrent illness on residual MCAD enzyme activity remains uncertain. There are, however, arguments in favour of abandoning the general advice to avoid prolonged fasting in subjects with variant ACADM genotypes and 10% residual MCAD enzyme activity.     

Polymorphism of the promotor region of the angiotensinogen gene and the gene for angiotensin I-converting enzyme in arterial hypertension and myocardial ischemia of the Kazakh ethnic groups

Polymorphism of the promoter region of the angiotensinogen gene (ATG) and an angiotensin I-converting enzyme gene (ACE) insertion/deletion (I/D) polymorphism were studied in three different groups of Kazakhs (control group, patients with cardiovascular disease (CAD) and patients with arterial hypertension (AH)) using three methods. A comparative analysis of the distribution of genotype and allele frequencies was conducted.     

Polymorphism of the Promoter Region of the Angiotensinogen Gene and the Gene for Angiotensin I-Converting Enzyme in Arterial Hypertension and Cardiovascular Disease of the Kazakh Ethnic Group

Polymorphism of the promoter region of the angiotensinogen gene (ATG) and an angiotensin I-converting enzyme gene (ACE) insertion/deletion (I/D) polymorphism were studied in three different groups of Kazakhs (control group, patients with cardiovascular disease (CAD) and patients with arterial hypertension (AH)) using three methods. A comparative analysis of the distribution of genotype and allele frequencies was conducted.     

The micronuclei frequencies in the buccal cell epithelium of young people of different age and gender in Ukraine

The results of study of micronuclei (MN) frequencies among the participants of Ukrainian school biological olympiads are presented. Totally 266 persons have been inspected. The distribution of MN frequencies correspond to the Poisson's distribution with lambda = 2.5. The average frequency of micronuclei in males was 2.4 +/- 0.15%, in females it was 2.7 +/- 0.14%. The difference of the average MN frequencies for these two groups was statistically insignificant. The individual micronuclei frequencies varied from 0 to 8.3%, the average MN frequency in the general group was 2.5 +/- 0.11%, (limits 2-5%). The micronuclei frequencies in different age groups of males and females were compared. Significantly higher MN frequencies in females than in males at the age of sixteen were detected. The age-related changes of micronuclei frequencies (14-18 age) were different for females compared to males.     

Distribution of AB0 and RH blood group alleles in different populations of southern Punjab, Pakistan.

The analysis of a sample of 1632 individuals from patients of the Nishtar Teaching Hospital, Multan, suggests that different ethnic groups (Araeen, Mughals, Syed, Jat, Rajputs, Baloch and Pathan) are not significantly different from another with regard to the distribution of RH blood group alleles (RH*d around 0.30). The distributions of the AB0 blood group alleles suggest that different ethnic groups are not significantly different from the average alele frequencies (AB0*A = 0.23, AB0*B = 0.33, AB0*0 = 0.47) except for the Pathan ethnic group (AB0*A = 0.35, AB0*B = 0.47, AB0*0 = 0.27). The populations of different geographic areas are not significantly different from the average allele frequencies, except for the southern district of Rahim Yar Khan (AB0*A = 0.12) and the northern district of Sahiwal (AB0*A = 0.19). The populations of Sahiwal (RH*d = 0.35) and Muzaffargarh (RH*d = 0.36) yield significantly different allele frequencies at the RH locus. The interpopulation differences can be explained by the geographic distance. There is a significant difference in the frequencies of the AB0 alleles between rural and urban populations, suggesting that rural populations maintain their isolation from urban populations. Rural and urban populations are not significantly different from one another concerning the allele frequencies at the RH locus.     

Natural and newly synthesized hydroxy-1-aryl-isochromans: a class of potential antioxidants and radical scavengers

We investigated the antioxidant and radical scavenging activity of polyphenolic isochromans. To assess the relation between structure and scavenging properties the natural occurring 1-(3'-methoxy-4'-hydroxy)phenyl-6,7-dihydroxy-isochroman (ISO-3, three OH groups) was compared with three newly synthesized derivatives that differ in their degree of hydroxylation by substitution with methoxy-groups (ISO-4: four OH groups; ISO-2: two OH groups and ISO-0: fully methoxylated). We found that ISO-4 is a 2-fold better scavenger for the artificial radical 1,1-diphenyl-2-picrylhydrazyl (DPPH, 100 microM) with an EC50=10.3 microM compared to the natural ISO-3 (EC50=22.4 microM) and to ISO-2 (EC50=25.1 microM), while ISO-0 did not react with DPPH. The scavenging capacity for superoxide enzymatically generated in a hypoxanthin-xanthinoxidase reaction was the highest for ISO-4 (EC50=34.3 microM) compared to those of ISO-3 (EC50=84.0 microM) and ISO-2 (EC50=91.8 microM), while ISO-0 was inactive. In analogy, ISO-4 scavenged peroxynitrite (ONOO-, EC25=23.0 microM) more effective than ISO-3, ISO-2 and ISO-0.When C6 rat glioma cells loaded with the reactive oxygen/nitrogen (ROS/RNS)-sensitive fluorochrome 2,7-dichlorodihydrofluorescein, were exposed to hydrogen peroxide, the lowest stress level as indicated by the fluorescence signal was detected when the cells were pretreated with ISO-4 or ISO-2 but to a much lesser extent with ISO-3, while ISO-0 did not show any effect. All tested hydroxyisochromans superceded the scavenging effect of trolox.The excellent radical and ROS/RNS scavenging features of the hydroxy-1-aryl isochromans and their simple synthesis let these compounds appear to be interesting candidates for pharmaceutical interventions that protect against the deleterious action of ROS/RNS.     

Intertribal and temporal allele-frequency variation at the ABO locus among Tibeto-Burman-speaking Adi subtribes of Arunachal Pradesh, India

We studied the distribution of ABO blood group frequencies of the Galo and Mishing subtribes of the Adi tribal cluster in East Siang District, Arunachal Pradesh, India, in order to investigate the intertribal and temporal allelic variation. Blood groups O and AB showed higher frequencies (28.4%, 27.4%) in the Galo, whereas group O (45%) was predominant in the Mishing. Allele r is significantly different in the Galo (44.6%) and Mishing (60.3%). The chi-square test indicated significant deviations from Hardy-Weinberg equilibrium. Adi tribes show high heterogeneity and indicate significant temporal variation in ABO genotype frequencies in the Galo, Mishing, and Padam, whereas the Panggi, a small isolated subtribe of Adi, show similar and stable frequencies.     

Genetic heterogeneity in acute intermittent porphyria: characterisation and frequency of porphobilinogen deaminase mutations in Finland.

The occurrence of different porphobilinogen deaminase mutant types in 68 patients with acute intermittent porphyria from 33 unrelated families in Finland was studied with biochemical and immunological techniques. In this fairly homogenous population four different porphobilinogen deaminase mutant types were identified and their frequencies determined. Most (about 80%) of the mutations were cross reacting immunological material (CRIM) negative, including a large kindred with normal erythrocyte porphobilinogen deaminase activities. The remainder of the families had CRIM positive mutations, including an unusual type (type 2) that had an immunoreactive, non-catalytic porphobilinogen deaminase level considerably greater than the maximal theoretical ratio of CRIM to activity of 2.0 for a single mutant allele. Correlations of the amount of residual porphobilinogen deaminase activity and the occurrence of acute clinical manifestations in each mutant type suggested that CRIM positive type 2 patients may have fewer acute symptoms.     

Characterisation of a highly hydrophobically modified lactate dehydrogenase

1. Lysine residues of porcine H4 lactate dehydrogenase (L-lactate:NAD+ oxidoreductase EC 1.1.1.27) were modified with methyl-epsilon-(N-2,4-dinitrophenyl)aminocaproimidate - HCl. With increasing incorporation of the reagent a linear decrease of enzymatic activity was noticed. No essential lysyl group with an extraordinary reactivity was modified. 2. The active forms of the modified enzyme with different incorporation values were separated from denatured material by fractional precipitation and gel chromatography. An epsilon-(N-2,4-dinitrophenyl)aminocaproamidinate lactate dehydrogenase was obtained with an average incorporation of 38 groups per tetramer and a residual activity of 42%. This material proved to be homogenous in cellulose electrophoresis. 3. The epsilon-(N-2,4-dinitrophenyl)aminocaproamidinate lactate dehydrogenase is soluble only in glycine buffer at pH 8 and can be stabilized as ternary complex with NAD+ and sodium sulfite. Gel chromatography and ORD measurements show no strong conformational change. 4. epsilon-(N-2,4-dinitrophenyl)aminocaproamidinate lactate dehydrogenase has similar Km values for pyruvate, NADH, lactate and NAD+ as the native enzyme, and shows a lower thermostability due to a diminished stabilization by the hydrate layer on the surface.     

Selection on structural allelic variation biases plasticity estimates

Wang and Althoff (2019) explored the capacity of Drosophila melanogaster to exhibit adaptive plasticity in a novel environment. In a full‐sib, half‐sib design, they scored the activity of the enzyme alcohol dehydrogenase (ADH) and plastic responses, measured as changes in ADH activity across ethanol concentrations in the range of 0–10% (natural variation) and 16% (the novel environment). ADH activity increased with alcohol concentration, and there was a positive association between larval viability and ADH activity in the novel environment. They also reported that families exhibiting greater plasticity had higher larval survival in the novel environment, concluding that ADH plasticity is adaptive. However, the four authors now concur that, since the study estimated plasticity from phenotypic differences across environments using full‐sib families, it is not possible to disentangle the contributions of allele frequency changes at the Adh locus from regulatory control at loci known to influence ADH activity. Selective changes in allele frequencies may thus conflate estimates of plasticity; any type of “plasticity” (adaptive, neutral, or maladaptive) could be inferred depending on allele frequencies. The problem of scoring sib‐groups after selection should be considered in any plasticity study that cannot use replicated genotypes. Researchers should monitor changes in allele frequencies as one mechanism to deal with this issue.     

Genetic linkage between Huntington disease and the D4S10 locus in South African families: further evidence against non-allelic heterogeneity

Summary A study of genetic linkage between Huntington disease (HD) and the D4S10 locus (G8) has been undertaken in 10 South African (SA) families originating from the black, white and mixed acestry population groups. Allele frequencies at the D4S10 locus have been established in the non-Caucasoid population groups. There are significant differences in the allele frequencies at the D4S10 locus between the various SA populations. Clearly, information about population-specific frequencies for all polymorphisms is essential prior to the implementation of predictive testing in different population groups. Linkage has been demonstrated within this mixed group of HD families in SA using the HindIII, EcoRI and MspI polymorphisms, detected by G8. A maximum lod score of 8.14 at a recombination fraction of 0.00 (confidence limit 0–0.058) has been calculated using a combined haplotype of the HindIII and MspI polymorphisms. Taking into account the diverse ethnic backgrounds of the different SA population groups in this investigation, the data obtained from the study provide further evidence that there is probably only a single HD locus.     

The A-B-O blood groups of baboons

A new series of 188 baboons, Papio papio, Senegal, have been tested for the human type A-B-O groups with the following results: 2 group O, 27 group A, 93 group B and 66 group AB. This distribution fits the Hardy-Weinberg formula perfectly, using the allele frequencies O = 10.3%, A = 29.0%, and B = 60.8%. Up to date, five series of baboons comprising a total of 684 animals have been tested for their A-B-O groups. On these 684 baboons, from three different species, only three belonged to group O. Nevertheless, there is convincing indirect evidence that in most of the baboon species tested so far the frequency of gene O is about 10%. There are significant differences in the distribution of the blood groups in the various baboon species, comparable to the differences in racial distribution of the A-B-O blood groups in man, e.g., the frequency of gene A ranges from 18.2% in Papio ursinus, South Africa, to 48.3% in Papio cynocephalus. The usefulness of the methods of population genetics, viz, allele frequency analysis, for studies of blood groups in primates is demonstrated. The differences and similarities between the A-B-O blood groups in man and baboons are discussed.     

Chemical modifications of Achromobacter collagenase and their influence on the enzymic activity

A study of the influence of chemical modifications on the activity of Achromobacter iophagus collagenase (EC 3.4.24.8) has led to the following conclusions: a modification of 4 out of 80 COOH groups with carbodiimide led to 90% loss of enzymic activity. A 70% inactivation was found after modification of two tyrosines out of 30 with tetranitromethane. The modification of four to six tryptophans out of 16 with 2-hydroxy-5-nitrobenzyl bromide decreased enzyme activity to 36%. This inactivation is accelerated in the presence of collagen. An increase of reagent/enzyme molar ratio led to a modification of 16 tryptophan residues and denaturation of Acahromobacter collagenase. A modification of two arginines out of 18 with 1,2-cyclohexanedione and eight NH2 groups out of 24 with 2,3-dimethyl maleic anhydride does not change the collagenolytic activity. All NH2 groups become available for 2,3-dimethyl maleic anhydride after dissociation of the dimer. A possible analogy of hydrolytic site of collagenase with that of two other known bacterial metalloproteinases (thermolysin and Bacillus subtilis neutral proteinase (EC 3.4.24.4)) is discussed.