Synopsis of the hard ticks (Acari: Ixodidae) of Romania with update on host associations and geographical distribution

The current paper is a synoptic review of the distribution and host associations of the 25 species of hard tick fauna (family Ixodidae) in Romania. In addition to a full literature survey, original data is presented, based on eight years of occasional or targeted sample collection. The literature data on geographical distribution was transposed digitally to the decimal degree coordinate system. For each species, an updated distribution map is given together with all historical data and new host associations. Overall, our paper records 58 new tick-host associations for Romania: 20 for Ixodes ricinus, 1 for I. apronophorus, 6 for I. arboricola, 2 for I. hexagonus, 9 for I. redikorzevi, 1 for I. trianguliceps, 2 for I. vespertilionis, 2 for Haemaphysalis punctata, 1 for H. sulcata, 2 for H. concinna, 1 for D. marginatus, 4 for Rhipicephalus sanguineus sensu lato, 1 for R. bursa and 6 for Hyalomma marginatum.     

Allocating resources for cancer control--resolving multicriteria decision-making using the analytic hierarchy process

When competing programs ought to be financed simultaneously for the same purpose, an allocation problem occurs due to scarce resources, and different perspectives and preferences. Facing the problem needs determining criteria which the decision might be based on. Those criteria form the objectives (the scope) of the different participants, and are relevant for the achievement of the goal, providing a comprehensive resource allocation that bridges and integrates the different perspectives. In case of cancer control primary prevention, secondary prevention, therapy and tertiary prevention, education, basic sciences, and clinical trials form the alternatives. An analytic hierarchy process (AHP) is used for supporting decision-making in the resource allocation problem. AHP is a method for setting priorities, but can only work out the implications of what was declared through the pairwise-ranking process, namely the relative preferences, weighing the criteria and rating the alternatives two by two. In the first analysis the relative weights to criteria were 0.099 for 'distributive justice'; 0.120 for constitutional and human rights; 0.251 for lay opinion; 0.393 for EBM; 0.137 for cost-effectiveness. Ranking the alternatives using 'judgements' resulted in relative preference of 0.238 for therapy, 0.204 for primary prevention, 0.201 for secondary prevention, 0.135 for clinical trials, 0.111 for tertiary prevention, 0.066 for basic sciences and 0.045 for education. In the second analysis the relative importance of "cost-effectiveness" was doubled, thus resulting in 0.234 for therapy, 0.216 for secondary prevention, 0.183 for primary prevention, 0.145 for clinical trials, 0.113 for tertiary prevention, 0.063 for basic sciences and 0.046 for education. Sensitivity analysis has shown that increasing the relative weight of cost-effectiveness up to approximately 0.4 changes the rank of alternatives, and above 0.4 this criterion gives secondary prevention preferences. According to the relative rates computed in both of the models all criteria vote for therapy, but these preferences change at the high level of weights, in case of EBM, 'rights', and cost-effectiveness. Cost-effectiveness prefers secondary prevention to therapy; the criterion of constitutional and human rights and the criterion of evidence-based medicine vote for primary prevention.     

New data on the European fauna of encyrtid wasps (Hymenoptera, Chalcidoidea, Encyrtidae)

On the basis of examination of the collection of the Natural History Museum (london), an annotated list of 36 encyrtid species with new records for 12 countries is given: one species new for both Ukraine and Croatia; two, for Austria, Cyprus, and Norway; three, for U.K.; four, for Germany and Spain; five, for Bulgaria; six, for Italy; eight, for France, and twelve, for Greece.     

Biology of Triatoma pallidipennis stal 1945 (Hemiptera: Reduviidae:Triatominae) under laboratory conditions

Aspects related to hatching, life time, mortality, feeding behaviour and fecundity for each stage of Triatoma pallidipennis life-cycle were evaluated. The hatching rate observed for 200 eggs was 60% and the average time of hatching was 18 days. Eighty nymphs (N) (40%) completed the cycle and the average time from NI to adult was 168. 7+/-11.7days. The average span in days for each stage was 18.0 for NI, 18.5 for NII, 30.0 for NIII, 35.7 for NIV and 50.1 for NV. The number of bloodmeals at each nymphal stage varied from 1 to 5. The mortality rate was 9.17 for NI, 5.5 for NII, 6.8 for NIII 4.17 for NIV and 13.04 for NV nymphs. The average number of eggs laid per female in a 9-month period was 498.6. The survival rates of adults were 357+/-217.9 and 262.53+/-167.7 for males and females respectively.     

Comparison of pure Holsteins to crossbred Holsteins with Norwegian Red cattle in first and second generations

A total of 1922 first generation crossbred cows born between 2005 and 2012 produced by inseminating purebred Israeli Holstein cows with Norwegian Red semen, and 7487 purebred Israeli Holstein cows of the same age in the same 50 herds were analyzed for production, calving traits, fertility, calving diseases, body condition score, abortion rate and survival under intensive commercial management conditions. Holstein cows were higher than crossbreds for 305-day milk, fat and protein production. Differences were 764, 1244, 1231 for kg milk; 23.4, 37.4, 35.6 for kg fat, and 16.7, 29.8, 29.8 for kg protein; for parities 1 through 3. Differences for fat concentration were not significant; while crossbred cows were higher for protein concentration by 0.06% to 0.08%. Differences for somatic cells counts were not significant. Milk production persistency was higher for Holstein cows by 5, 8.3 and 8% in parities 1 through 3. Crossbred cows were higher for conception status by 3.1, 3.6 and 4.7% in parities 1 through 3. Rates of metritis for Holsteins were higher than the crossbred cows by 7.8, 4.6 and 3.4% in parities 1 to 3. Differences for incidence of abortion, dystocia, ketosis and milk fever were not significant. Holstein cows were lower than crossbred cows for body condition score for all three parities, with differences of 0.2 to 0.4 units. Contrary to comparisons in other countries, herd-life was higher for Holsteins by 79 days. A total of 6321 Holstein cows born between 2007 and 2011 were higher than 765 progeny of crossbred cows backcrossed to Israeli Holsteins of the same ages for milk, fat and protein production. Differences were 279, 537, 542 kg milk; 10.5, 17.7, 17.0 kg fat and 6.2, 12.9, 13.2 kg protein for parities 1 through 3. Differences for fat concentration were not significant, while backcross cows were higher for protein percentage by 0.02% to 0.04%. The differences for somatic cell score, conception rate, and calving diseases other than metritis, were not significant. Holstein cows were lower than backcross cows by 1.5% to 2.5% for conception status in parities 1 to 3 and lower for body condition score for parities 1 and 2, with differences in the range of 0.06 to 0.09 units. Culling rates were higher, and herd-life lower for the crossbred cows. The gains obtained in secondary traits for crossbred cows did not compensate for the major reduction in production.     

Genetic parameter estimates in a clonally replicated progeny test of teak (Tectona grandis Linn. f.)

Teak (Tectona grandis Linn. f.) has been planted extensively in the tropics for its highly valued timber. We analysed data from a 3.5-year-old teak progeny test with clonal replication located in northern Australia. Additive and non-additive genetic variances were estimated for commercially important traits. Trees originating from seedlings were on average 2% taller and 4% straighter than those of the same genotype originating from cuttings. Non-additive genetic variance represented 35–50% of total genetic variance for growth traits and 63% of total genetic variance for incidence of flowering. Narrow-sense heritability was 0.22 for diameter, 0.18 for height and volume, 0.07 for stem straightness, 0.05 for insect defoliation, 0.03 for epicormic sprouts and 0.30 for incidence of flowering (estimated on an assumed underlying continuous scale). Broad-sense heritability was 0.37 for diameter, 0.28 for height, 0.35 for volume, 0.12 for stem straightness, 0.06 for insect defoliation, 0.12 for epicormic sprouts and 0.71 for incidence of flowering. Positive correlations were found between tree volume and flowering and between tree volume and stem straightness. The presence of sizeable non-additive variance supports the selection and deployment of clones to capture the full extent of genetic variation in commercially important traits.     

Destructive effect of heating against toxoplasma oocysts.

Heating was examined for destructive effect against Toxoplasma oocysts, both unsporulated and sporulated, of the O-1 and O-3 strains. Sporulation-inhibition rates were measured by counting sporulated and unsporulated oocysts in each examination. As a result, the sporulation of Toxoplasma oocysts was completely inhibited by exposure to 60 or 70 degrees C for 10 seconds, 55 degrees C for 30 seconds, 50 degrees C for 2.5 minutes. 45 degrees C for 1 hour, or 37 degrees C for 48 hours. When examined by the mouse inoculation method, the infectivity of sporulated oocysts became extinct after heating at 90 degrees C for 30 seconds, 80 degrees C for 1 minute, 70 degrees C for 2 minutes, 55 or 60 degrees C for 15 minutes, or 50 degrees C for 30 minutes. It was confirmed that heating was effective for the sterilization of Toxoplasma oocysts.     

Distribution of adenylate kinase and phosphoglucomutase isoenzymes in the population of the city of New York.

Blood samples from unrelated persons living in New York, N.Y., were examined for phosphoglucomutase (PGM) and adenylate kinase (AK) phenotypes, the sample consisting of 164 Caucasians, 133 Negroes, 129 persons of Spanish origin or descent, and 156 Chinese for PGM and 136 Caucasians, 134 Negroes, 136 persons of Spanish origin or descent, and 156 Chinese for AK. The PGM1 gene frequency was found to be 0.7774 for Caucasians, 0.8083 for Negroes, 0.7461 for Hispanic persons, and 0.7917 for Chinese. One Hispanic person had a very rare type, PGM 8-1-FAST. The AK1 gene frequency was found to be 0.9669 for Caucasians, 0.9813 for Negroes, 0.9779 for Hispanic persons, and 1.000 for Chinese.     

Japanese sleep disturbance and fatigue disability weights in evaluating the effects of increasing temperatures on health by a life cycle approach

Purpose

This study aimed to establish a set of disability weights (DWs) for sleep problems and fatigue which could be applied in composite health outcome measures in order to quantify the burden of symptoms and economically evaluate the effects of increasing temperatures on a life cycle approach.

Methods

The conditions were evaluated by a two-step questionnaire study. In the first step, specialists determined the DW for each condition. The second step was identical to the first, except that the determinations were made by primary care physicians. Both groups of medical practitioners used an interpolation method consisting of a comprehensive set of 31 disease-specific DWs.

Results and discussion

Mean DWs for sleep disturbance were 0.101 for environmental sleep disturbance, 0.069 for mild sleep disturbance, and 0.086 for moderate sleep disturbance. Mean DWs for chronic fatigue syndrome (CFS) were 0.099 for a diagnosis of CFS, 0.164 for mild handicap, 0.281 for moderate handicap, and 0.459 for severe handicap. Mean DWs assigned by primary care physicians for sleep disturbance were 0.114 for environmental sleep disturbance, 0.140 for mild sleep disturbance, and 0.126 for severe sleep disturbance. Those for CFS were 0.154 for a diagnosis, 0.099 for mild handicap, 0.147 for moderate handicap, and 0.226 for severe handicap.

Conclusions

Using the present valuation protocol, it appeared feasible to establish the burden of symptoms as attributable to increasing temperatures. The results can be applied in composite health outcome measures for public health research, environmental research, and economic evaluations.     

十种一碳代谢关键产物的HPLC-MS/MS 定量检测方法

目的:利用HPLC-MS/MS方法对十种一碳代谢相关产物进行定量分析。方法:采用Aglient ZORBAX SB-AQ C18柱(2.1mm×100 mm,3.5 m)、电喷雾离子源(ESI),以多离子反应监测方式(MRM)进行正离子检测。对游离叶酸(FA)、5-甲酰四氢叶酸(5-FT)、5-甲基四氢叶酸(5-MT)、S-腺苷蛋氨酸(SAM)、S-腺苷同型半胱氨酸(SAH)、胱硫醚(CYSTA)、组氨酸(HIS)、丝氨酸(SER)、蛋氨酸(MET)、同型半胱氨酸(HCY)进行定量分析。结果:FA、5-FT、5-MT、SAM、SAH、CYSTA、HIS、SER、MET、HCY的检测限分别为0.1 ng.L-1、0.25 ng.L-1、0.1 ng.L-1、0.1 ng.L-1、0.25 ng.L-1、0.25 ng.L-1、0.1 ng.L-1、0.025 ng.L-1、0.1 ng.L-1、0.1 ng.L-1。FA、5-FT、5-MT、SAH、CYSTA浓度测定方法线性范围为2~50 ng.L-1,SER、SAM浓度测定方法线性范围20~500 ng.L-1,MET、HCY浓度测定方法线性范围200~5000 ng.L-1,HIS浓度测定方法线性范围为400~10000 ng.L-1,r均在0.993以上,全部涵盖了已报道的血清中指标的含量范围。结论:建立了HPLC-MS/MS方法,可同时分析十种一碳代谢通路的关键产物,所需样品量少,检测速度快,同时实现分项检测,可为多种代谢性疾病系统性地检测一碳代谢中间产物体液分析方法建立实验条件基础。     

Performance of dairy cattle clones and evaluation of their milk composition

Genetic and phenotypic performance of U.S. Holstein embryo-split and nuclear-transfer clones was documented for yield and fitness traits. For cows, mean genetic superiority based on pedigree was 186 kg of milk, 9 kg of fat, and 7 kg of protein for embryo-split clones and 165, 10, and 8 kg, respectively, for nuclear-transfer clones compared with the population for the same birth year; pedigree advantage for male clones generally was slightly greater. Estimates of genetic merit that considered a clone's own performance as well as pedigree merit were slightly lower for embryo-split cows than for their full siblings for yield but not for milk composition (fat and protein percentages), mastitis resistance (somatic cell score), longevity (productive life), or cow fertility (daughter pregnancy rate); no corresponding genetic differences were found for nuclear-transfer cows or for cloned bulls regardless of clone type. For bulls, estimated genetic merit based on daughter yield was more similar for clone pairs with apparent identical genotype than for pairs from the same biotechnology but nonidentical as confirmed by blood typing. Yield deviations were lower for clones than for their full siblings. Milk composition (total solids, fat, fatty acid profile, lactose, and protein) also was compared for nuclear-transfer clones (Brown Swiss, Holstein, and Holstein-Jersey cross) with non-cloned cows and literature values; no differences were found for gross chemical composition of milk. No obvious differences were evident between cloned and non-cloned animals or for the milk that they produced.     

RFLP mapping of QTLs for yield and related characters in rice (Oryza sativa L.)

Quantitative triat loci (QTLs) for yield and related traits in rice were mapped based on RFLP maps from two indica/indica F₂ populations, Tesanai 2/CB and Waiyin 2/CB. In Tesanai 2/CB, 14 intervals carrying QTLs for eight traits were detected, including 3 for grain weight per plant (GWT), 2 for number of panicles per plant (NP), 2 for number of grains per panicle (NG), 1 for total number of spikelets per panicle (TNS), 1 for spikelet fertility (SF), 3 for 1000-grain weight (TGWT), 1 for spikelet density (SD), and 1 for number of first branches per main panicle. The 3 QTLs for GWT were located on chromosomes 1, 2, and 4, with 1 in each chromosome. The additive effect of the single locus ranged from 2.0 g to 9.1 g. A major gene (np4) for NP was detected on chromosome 4 within the interval of RG143–RG214, about 4cM for RG143, and this locus explained 26.1% of the observed phenotypic variance for NP. The paternal allele of this locus was responsible for reduced panicles per plant (3 panicles per plant). In another population, Waiyin 2/CB, 12 intervals containing QTLs for six of the above-mentioned traits were detected, including 3 for GWT, 2 for each of NP, TNS, TGWT and SD, 1 for SF. Three QTLs for GWT were located on chromosome 1, 4, and 5, respectively. The additive effect of the single locus for GWT ranged from 6.7 g to 8.8 g, while the dominance effect was 1.7–11.5 g. QTL mapping in two populations with a common male parent is compared and discussed.     

Thermal requirements of Galleria mellonella L. (Lepidoptera: Pyralidae) immature stages

The rearing of Galleria mellonella L. in laboratory is important for multiplication of entomopathogenic nematodes, mandatory for biological control studies. The objective of this study was to evaluate the effect of three thermal profiles on development stages of this insect, allowing synchronization of cycle production. Two distinct rearing phases were done: firstly, using nucleous of incubation for development of eggs and, secondly, using circular-aluminum manifolds for development of larvae and pupae. The time necessary for development of the immature stages decreased with higher temperatures. Incubation periods lasted 13.4 days at 22 degrees C, 8.3 at 27 degrees C and 6.8 days at 32 degrees C, while periods for larvae development lasted 40.4, 27.2, and 23.4 days, respectively, for the same temperatures. Development to pupal stage was observed 18.2, 15.0, and 12.2 days, respectively, for the same temperatures. Larval survival was higher at 32 degrees C, however embryonic stages and pupae survival were higher at 27 degrees C. and 22 degrees C, respectively. The threshold temperature was 11.209167 degrees C for the embryonic development stage, 7.695869 degrees C for larval stage, and 1.943050 degrees C for pupal stage of G. mellonella. Thermal constants were 138.380533 DG (degree day) for egg, 554.968830 DG for larvae, and 369.054080 DG for pupae.     

Determination of cediranib in mouse plasma and brain tissue using high-performance liquid chromatography-mass spectrometry

A new high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) assay for cediranib, a tyrosine kinase inhibitor for VEGFRs, was developed and validated, for the determination of plasma and brain levels of cediranib in small specimen volumes. Tyrphostin (AG1478) was used as internal standard. Mouse plasma and brain homogenate samples were prepared using liquid-liquid extraction. The assay was validated for a 2.5-2500 ng/mL concentration range for plasma, and for 1-2000 ng/mL range for brain homogenate. For these calibration ranges, within-assay variabilities were 1.1-14.3% for plasma and 1.5-9.4% for brain homogenate; between-assay variabilities were 2.4-9.2% for plasma, and 4.9-10.2% for brain homogenate. Overall accuracy ranged from 101.5 to 107.0% for plasma and 96.5 to 100.2% for brain homogenate, for all target concentrations. The developed assay has been successfully applied for a brain distribution study in mice at an oral dose of 5 mg/kg.     

Molecular mapping of quantitative trait loci for drought tolerance in maize plants

Drought tolerance is one of the most important but complex traits of crops. We looked for quantitative trait loci (QTLs) that affect drought tolerance in maize. Two maize inbreds and their advanced lines were evaluated for drought-related traits. A genetic linkage map developed using RFLP markers was used to identify QTLs associated with drought-related traits. Twenty-two QTLs were detected, with a minimum of one and a maximum of nine for drought-related traits. A single-QTL was detected for sugar concentration accounting for about 52.2% of the phenotypic variation on chromosome 6. A single-QTL was also identified for each of the traits root density, root dry weight, total biomass, relative water content, and leaf abscisic acid content, on chromosomes 1 and 7, contributing to 24, 0.2, 0.4, 7, and 19% of the phenotypic variance, respectively. Three QTLs were identified for grain yield on chromosomes 1, 5, and 9, explaining 75% of the observed phenotypic variability, whereas four QTLs were detected for osmotic potential on chromosomes 1, 3, and 9, together accounting for 50% of the phenotypic variance. Nine QTLs were detected for leaf surface area on chromosomes 3 and 9, with various degrees of phenotypic variance, ranging from 25.8 to 42.2%. Four major clusters of QTLs were identified on chromosomes 1, 3, 7, and 9. A QTL for yield on chromosome 1 was found co-locating with the QTLs for root traits, total biomass, and osmotic potential in a region of about 15 cM. A cluster of QTLs for leaf surface area were coincident with a QTL for osmotic potential on chromosome 3. The QTLs for leaf area also clustered on chromosome 9, whereas QTLs for leaf abscisic acid content and relative water content coincided on chromosome 7, 10 cM apart. Co-location of QTLs for different traits indicates potential pleiotropism or tight linkage, which may be useful for indirect selection in maize improvement for drought tolerance.     

Epistatic Association Mapping for Alkaline and Salinity Tolerance Traits in the Soybean Germination Stage

Soil salinity and alkalinity are important abiotic components that frequently have critical effects on crop growth, productivity and quality. Developing soybean cultivars with high salt tolerance is recognized as an efficient way to maintain sustainable soybean production in a salt stress environment. However, the genetic mechanism of the tolerance must first be elucidated. In this study, 257 soybean cultivars with 135 SSR markers were used to perform epistatic association mapping for salt tolerance. Tolerance was evaluated by assessing the main root length (RL), the fresh and dry weights of roots (FWR and DWR), the biomass of seedlings (BS) and the length of hypocotyls (LH) of healthy seedlings after treatments with control, 100 mM NaCl or 10 mM Na₂CO₃ solutions for approximately one week under greenhouse conditions. A total of 83 QTL-by-environment (QE) interactions for salt tolerance index were detected: 24 for LR, 12 for FWR, 11 for DWR, 15 for LH and 21 for BS, as well as one epistatic QTL for FWR. Furthermore, 86 QE interactions for alkaline tolerance index were found: 17 for LR, 16 for FWR, 17 for DWR, 18 for LH and 18 for BS. A total of 77 QE interactions for the original trait indicator were detected: 17 for LR, 14 for FWR, 4 for DWR, 21 for LH and 21 for BS, as well as 3 epistatic QTL for BS. Small-effect QTL were frequently observed. Several soybean genes with homology to Arabidopsis thaliana and soybean salt tolerance genes were found in close proximity to the above QTL. Using the novel alleles of the QTL detected above, some elite parental combinations were designed, although these QTL need to be further confirmed. The above results provide a valuable foundation for fine mapping, cloning and molecular breeding by design for soybean alkaline and salt tolerance.     

A population model based on a life table that includes marriage and parity.

This paper presents a method for constructing a one-sex life table that incorporates age, marriage and parity. The life table is the basis for a generalized population model, with immediate extension to a stable population differentiated by age, marriage and parity status. The method is quite general and could be extended, without major modification, to more complex life tables.Computation of intrinsic rates of increase for a number of populations adjusted for age, for age and parity, for age and marriage, and for age, marriage and parity shows that adjustment for marriage accounts for most of the difference between the age-adjusted rate and the age-, marriage-, and parity-adjusted rate. Adjustment for parity without adjustment for marriage may be misleading.     

感染与早产儿脑损伤临床关系探讨

目的:探讨感染与早产儿脑损伤(HIE,ICH,CWMD)的临床表现,治疗,预后和预防的关系。方法:对2000年1月-2006年10月214例早产儿进行临床分析。结果:胎膜早破32例,母亲妊高症23例,胎儿宫内窘迫33例,脐带扭转打结7人,母亲妊娠糖尿病4人,胎儿畸形4人;早产儿肺炎101人,早产儿寒冷损伤综合征7人,早产儿急性坏死性小肠结肠炎5人,低血糖症27人,低血钙症13人,早产儿缺氧缺血性脑病(HIE)76人,早产儿颅内出血(ICH)21人,早产儿脑白质损伤(CWMD)3人。早期诊断、合理抗感染治疗可减少早产儿HIE及ICH以及CWMD患儿的神经系统后遗症。结论:早产儿感染与HIE及ICH以及CWMD的关系密切,预防产前、产时、产后感染对减少或减轻早产儿脑损伤至关重要。     

Bioconcentration and excretion of diazinon, IBP, malathion and fenitrothion by carp

1. Bioconcentration and excretion of diazinon, IBP, malathion and fenitrothion were studied for carp (Cyprinus carpio L.). 2. The concentrations of these pesticides in muscle and viscera of the carp reached plateaus in 12-48 hr exposure. 3. The average values of bioconcentration factors (BCF) for diazinon were 20.9 in muscle, 60.0 in liver, 111.1 in kidney and 32.2 in gallbladder over the 168 hr exposure period. Similarly, those values were 4.3-26.7 for IBP, 2.7-17.3 for malathion, and 36.0-157.1 for fenitrothion. 4. The excretion rate constants of malathion (hr-1) were 0.13 for muscle, 0.12 for liver, 0.08 for kidney and 0.06 for gallbladder. Those of diazinon, IBP and fenitrothion (g.ng-1.hr-1) were 0.002-0.024 for muscle, 0.001-0.020 for liver, 0.0004-0.004 for kidney and 0.002-0.023 for gallbladder, respectively.     

Characterization of six nucleoside-nucleotide phosphotransferases from the chromatin of Morris hepatoma 9121 cells by physicochemical and biochemical techniques

1. Six nucleoside-nucleotide phosphotransferases A-F were isolated from chromatin of Morris Hepatoma 9121 cells and characterized. 2. The apparent mol wt are: 13,000 daltons for A, 35,000 or 70,000 for B and E, 240,000 for C, 180,000 for D and 300,000-400,000 for F. 3. The sedimentation values are: 2.5-3 S for A, 3 or 5 S for B and E, 11 S for C, 7-8 S for D and 14 S for F. 4. The activity of the six enzymes A-F was stimulated with 1-2.5 micrograms calf thymus DNA using thymidine/ATP as substrates. 5. In the presence of defined polydeoxynucleotides, each enzyme A-F showed a differential preference for its substrates.