Differential accumulation of cadmium in near-isogenic lines of durum wheat: no role for phytochelatins

Certain cultivars of some crops, including durum wheat (Triticum durum Desf.), have a propensity to accumulate cadmium in the grain. In the 1980s, a Canadian wheat breeding program generated five pairs of near-isogenic lines of durum wheat that vary in cadmium-accumulation. Within each pair, one member accumulates twofold to threefold higher concentrations of cadmium in the shoot and grain. However, the physiological explanation for the high-low phenotype is unknown. We studied correlations between concentrations of cadmium and non-protein thiols, including phytochelatins, in these five pairs of near-isogenic lines to test the hypothesis that differential retention of cadmium-binding complexes in the root would explain the phenotype. The expected high-low pattern of cadmium accumulation was found in three of the pairs. In one pair, cadmium was positively correlated with cysteine and glutathione in the roots and with phytochelatins 2 and 4 in the shoots but in another pair cadmium was strongly negatively correlated with phytochelatins 2 and 4 in the shoots and unrelated to cysteine or glutathione. No correlations between concentrations of cadmium and the non-protein thiols were found in the third pair or in the remaining two pairs. The production of phytochelatins is a well-described response to cadmium but the lack of consistent correlation between cadmium and non-protein thiols in these five near-isogenic lines indicates that complexation with non-protein thiols does not explain differential translocation of cadmium in durum wheat.     

NUCLEAR INCORPORATION OF RADIOACTIVE DNA PRECURSORS AND PROGRESSION OF CELLS THROUGH S

Bone marrow blast cells of nine children with untreated acute leukaemia (five lymphoid, three myeloid, one monocytic), myeloid precursor cells of a haema-tologically normal child and thoracic duct lymph cells of a patient with sclerodermia were pulse-labelled in vitro with tritiated thymidine and/or tritiated cytidine. Combined radioautographic and cytophotometric techniques were used for the determination of the median nuclear size and the median grain count of labelled cells in different segments of S. It was found that the median grain count reached maximum values in the second or third quarter of S in all cell populations studied, and that the variation, during S, of the median grain count appeared to be independent of the median DNA synthesis times of the cell types investigated. In six cell populations a clear-cut inverse relation existed between the number and the median grain count of labelled cells in different segments of S. In three populations this relation was less apparent and in two it was not found at all.     

Autoradiographic study on the synthesis of nuclear proteins

Experiments were carried out on cultures of Chinese hamster fibroblasts. Cells were short-labelled with H³-Iysine or H³-tryptophane. The kinetics of silver grain number over interphase nuclei, metaphases, and individual chromosomes of the first pair were studied. — The grain count distribution over chromosomes of different groups and over sister-chromatids was analyzed. The data presented allow us to conclude that: 1. There is equal distribution of nuclear and chromosomal proteins between daughter nuclei and sister-chromatids, resp., during each mitotic cycle. 2. The synthesis of chromosome proteins, in general, and nonhistone proteins, in particular, takes place at all stages of the cycle. 3. At each stage of the cycle, proteins are incorporated into chromosomes of different groups simultaneously and at equal rate. The rate of this process in S and G2 is two times that in G1.     

The configuration of the seminal roots of Triticum aestivum L. (Poaceae)

The seminal root system of wheat (Triticum aestivum L.) is composed of the primary seminal root, the first pair of seminal roots, and the second pair of seminal roots, which are known to grow in different directions. The direction of root growth, which can be expressed by theta (the angle between the root and the plumb line) and phi (the angle between the root and a vertical plane including the primary seminal root), was studied with special attention to the latter. It was measured on seedlings grown in a small hemispherical soil-filled mesh basket. There were varietal differences in the phi of the first pair of roots (phi f) and in the phi of the second pair of roots (phi s). phi f and phi s were significantly correlated. The mean distance (MD), a measure to evaluate the efficiency of root spacing, was correlated with the difference between phi f and phi s. Neither experimentally applied low soil water potential nor the excision of the primary seminal root affected phi. When the grain was sown vertically with the tip of the embryo pointing downwards, it was found that the growth movement into a direction different from the plumb line and phi s was greatly modified. It is suggested that certain internal mechanisms, possibly involving gravitropic reactions, are operating to control the direction of root growth. The significance of root growth direction at the seedling stage is discussed.     

A dermatoglyphic study of the Kavalan aboriginal population of Taiwan

By the 1970s, a number of dermatoglyphic studies of Taiwan aborigines (Gaoshan nationality) had been published, however in each only a few dermatoglyphic variables were addressed. Since that time, little new research has been conducted. In this study, we collected and analyzed the dermatoglyphs of 100 individuals of Kavalan, a Taiwan aboriginal population, and we reported a wide range of dermatoglyphic variables including total finger ridge count (TFRC), a-b total ridge count (a-b RC), atd angle and axial triradius percent distance (tPD), and frequencies of fingerprint pattern, palmar thenar pattern, palmar interdigital pattern, palmar hypothenar pattern, and simian line. This study is the first comprehensive dermatoglyphic research of any Taiwan aboriginal population.     

A dermatoglyphic study of the Kavalan aboriginal population of Taiwan

By the 1970s, a number of dermatoglyphic studies of Taiwan aborigines (Gaoshan nationality) had been published, however in each only a few dermatoglyphic variables were addressed. Since that time, little new research has been conducted. In this study, we collected and analyzed the dermatoglyphs of 100 individuals of Kavalan, a Taiwan aboriginal population, and we reported a wide range of dermatoglyphic variables including total finger ridge count (TFRC), a-b total ridge count (a-b RC), atd angle and axial triradius percent distance (tPD), and frequencies of fingerprint pattern, palmar thenar pattern, palmar interdigital pattern, palmar hypothenar pattern, and simian line. This study is the first comprehensive dermatoglyphic research of any Taiwan aboriginal population.     

COMPUTER SUBTRACTION OF BACKGROUND IN AUTORADIOGRAPHY WITH TRITIATED THYMIDINE

An iterative method is suggested to estimate true labelling index even when background and experimental (background + true labelling) grain count distributions appear to be incompatible, generally a result of unavoidably insufficient counting in routine work. A computer program applying the iterative method has been written in Fortran IV for an IBM 1130 machine. This program, available on request, displays grain count distributions before as well as after correction and computes the labelling index and average grain count per labelled cell, with respective variance and standard errors.     

Variation in tritiated thymidine uptake during DNA synthesis in the adrenal cortex

Summary The interphase grain counts of adrenocortical cells labelled with tritiated thymidine (³H) Tdr,do not conform to a Poisson distribution, and therefore are not the result of a random disintegration process. The rate of (³H) Tdr incorporation during interphase DNA synthesis (the S phase) was studied by metaphase grain count analysis. Maximum rates of incorporation were found towards the middle of the S phase. The interphase grain count of adrenocortical cells is considered to be largely dependent on the position of the cell in the S phase.     

A dermatoglyphic study of the Amis aboriginal population of Taiwan

Amis is the largest aboriginal population in Taiwan. The previous dermatoglyphic studies of the Amis only reported limited data. In this study, we collected and analyzed the dermatoglyphs of 200 Amis in-dividuals, and we reported a wide range of dermatoglyphic variables including total finger ridge count, a-b ridge count, atd angle, axial triradius percent distance, and frequencies of fingerprint pattern, pal-mar thenar pattern, palmar interdigital pattern, and simian line. This study is the first comprehensive dermatoglyphic research of Amis since 1960s, and its dermatoglyphic data will be useful for future re-search in anthropology, genetics and medicine.     

A dermatoglyphic study of the Amis aboriginal population of Taiwan

Amis is the largest aboriginal population in Taiwan. The previous dermatoglyphic studies of the Amis only reported limited data. In this study, we collected and analyzed the dermatoglyphs of 200 Amis individuals, and we reported a wide range of dermatoglyphic variables including total finger ridge count, a-b ridge count, atd angle, axial triradius percent distance, and frequencies of fingerprint pattern, palmar thenar pattern, palmar interdigital pattern, and simian line. This study is the first comprehensive dermatoglyphic research of Amis since 1960s, and its dermatoglyphic data will be useful for future research in anthropology, genetics and medicine.     

栽培模式对冬小麦光能利用和产量的影响

以‘泰农18’小麦为材料,于2012—2013年进行大田试验,设置当地农民习惯栽培模式(FP)、超高产栽培模式(SH)和高产高效栽培模式(HH)3个处理,研究了不同栽培模式对小麦光能截获量、光能利用效率、干物质积累量、收获指数、籽粒产量和肥料偏生产力的影响.结果表明: SH模式小麦全生育期的光能截获量、光能利用效率、干物质积累量和籽粒产量显著高于FP模式.相对于FP模式,虽然HH模式的小麦全生育期光能截获量较低,但其光能利用效率、干物质积累量及收获指数均显著提高,从而使其籽粒产量显著提高.相对于SH模式,虽然HH模式的籽粒产量在高、低肥力水平下分别降低3.8%和2.8%,而氮、磷、钾肥的偏生产力在两肥力水平下分别提高26.4%、68.5%、92.6%.在本试验条件下,综合考虑籽粒产量和养分利用效率,以“降肥、增密、延播”为技术特点的高产高效栽培模式为推荐的优化栽培模式.     

水稻籽粒灌浆过程中超弱发光特性的研究

本实验对水稻籽粒灌浆过程中不同时期籽粒进行了超弱发光测定。实验结果表明：在整个灌浆过程中单粒发光量呈单峰曲线,在籽粒全部充实并且颜色由青转黄时,发光量最大;发光强度呈递减趋势;运用该技术有可能进行水稻不同品种间的比较和品种灌浆力强弱的筛选。     

Enhanced susceptibility of DNA-synthesizing nuclei of epithelial cells of the intestine to acid hydrolysis

Summary Albino mice were injected intraperitoneally with tritiated thymidine and killed 1/2 and 30 h later. Pieces of ileum were excised and fixed. Tissue sections were hydrolyzed with 5 N HCl at 21° C for 1/2, 1, 2, 3, 4 and 6 h, some sections remained unhydrolyzed. Both the hydrolyzed and nonhydrolyzed sections were autoradiographed. Grain counts per labelled nucleus of either cryptal (DNA-synthesizing) or villous (DNA-nonsynthesizing) cells nonhydrolyzed and hydrolyzed for various time intervals were recorded.The results indicate, that the grain count of nonhydrolyzed, labelled nuclei from cryptal cells was by 1.49 higher than that of villous cells demonstrating the rate of grain counts diminution caused by cell divisions.Hydrolysis caused a diminution of grain count of cryptal cells by approximately 15% higher than that of the grain count of villous cells.Financial support was partially obtained from grant MR II.1.We wish to thank Dr. W. Sawicki for his supervision, advice and encouragement throughout this work     

Estimating the Median Generation Time of Proliferating Cell Systems in Steady State

For proliferating cell systems in which the usual "labeled mitoses" method cannot be used to estimate generation times, an alternative scheme is derived. The method presented here is based on observation (by autoradiography) of the median grain count of labeled interphase cells following a pulse of labeled DNA precursor. It is shown that the median generation time of the labeled cells will be equal to the time required for the median grain count to halve, starting from the time when half the labeled cells have completed their first division. This starting time is determined from observation of the first wave of labeled mitoses. The procedure was designed to minimize error resulting from such factors as radiation damage, label reutilization, and the use of a nonzero grain counting threshold. The method is applied to the analysis of two cases of acute leukemia in man.     

Quantification of unscheduled DNA synthesis by a whole cell counting method

A procedure was developed for the quantification of the autoradiographic assay for unscheduled DNA synthesis. Relative to commonly used practices for grain counting, this procedure provides a more accurate net nuclear grain count by eliminating the subjectivity currently associated with selection of the areas to be counted for the cytoplasmic background count. Briefly, the object area and aperture area modes of an ARTEK 880 colony counter are used to collect values for the total number of silver grains over a particular cell (nuclear and cytoplasmic counts), as well as for the nuclear and cytoplasmic areas. These values are then employed in a short algorithm to determine the net nuclear grain count. This new method provides greater sensitivity for defining weak UDS responses and the data collected readily lends itself to statistical analysis.     

不同斑块类型的景观指数粒度效应响应——以无锡市为例

斑块类型与景观格局粒度效应响应关系密切。以无锡市为研究区域,针对地区社会经济活动频繁、人为干扰强烈和生态脆弱等特性,以土地利用类型、热力等级和生态贡献为斑块类型划分依据,构建出对应的3种不同景观格局。在相同粒度变化情况下,选用了19个景观水平指数和Moran's I指数,分析了不同景观格局粒度效应的响应情况。结果表明,随粒度变粗:1)土地利用类型、热力等级和生态贡献斑块的部分景观指数响应曲线变化剧烈程度依次减弱;2)3类斑块的Moran's I指数均存在尺度效应。其中,土地利用类型和生态贡献斑块的Moran's I指数存在负相关,热力等级斑块没有。生态贡献斑块响应曲线在正相关区域内变化相对平缓,土地利用类型与热力等级斑块响应曲线变化趋势相反;3)指数反映的第一临界粒度基本一致,但景观指数响应曲线的临界现象更为明显。总体上,不同类型斑块在同一研究区构成的景观格局、指数响应曲线变化趋势和第一临界粒度都较为相似;斑块类型对景观指数粒度效应响应存在影响,但还有待深入探讨。     

Cytogenetic analysis of three species of the genus <Emphasis Type="Italic">Haemulon</Emphasis> (Teleostei: Haemulinae) from Margarita Island,Venezuela

This paper describes the karyotype analysis of Haemulon aurolineatum, Haemulon bonariensis and Haemulon plumierii, by Giemsa staining, C-banding, Ag-staining and fluorescent in situ hybridization (FISH), to locate the 18S and 5S rRNA genes. Diploid modal count in the three species was 2n = 48 acrocentric elements. Except for pair 24, which exhibited an unmistakable secondary constriction in all three species, it was not possible to classify them as homologous to each other because differences in chromosome size were too slight between adjacent pairs within a size-graded series. Ag-NOR clusters were located in pair 24 in the three species with signal located on the secondary constriction of these chromosomes. C-banding demonstrated that the three species share the same distribution pattern of the constitutive heterochromatin with centromeric heterochromatic blocks in the 23 chromosome pairs and a pericentromeric block in pair 24 which is coincident with the NORs. FISH experiments showed that 18S rDNA sequences were located coincident with the Ag-NOR site in the three species; however, differences in both the number and chromosome distribution of 5S-rDNA cluster were detected among them. Our data suggest that chromosome evolution of Haemulon has been preserved from major changes in the karyotypic macrostructure, whereas microstructural changes have occurred.     

Enzymatic incorporation of a third nucleobase pair

DNA polymerases are identified that copy a non-standard nucleotide pair joined by a hydrogen bonding pattern different from the patterns joining the dA:T and dG:dC pairs. 6-Amino-5-nitro-3-(1'-beta-D-2'-deoxyribofuranosyl)-2(1H)-pyridone (dZ) implements the non-standard 'small' donor-donor-acceptor (pyDDA) hydrogen bonding pattern. 2-Amino-8-(1'-beta-D-2'-deoxyribofuranosyl)-imidazo[1,2-a]-1,3,5-triazin-4(8H)-one (dP) implements the 'large' acceptor-acceptor-donor (puAAD) pattern. These nucleobases were designed to present electron density to the minor groove, density hypothesized to help determine specificity for polymerases. Consistent with this hypothesis, both dZTP and dPTP are accepted by many polymerases from both Families A and B. Further, the dZ:dP pair participates in PCR reactions catalyzed by Taq, Vent (exo-) and Deep Vent (exo-) polymerases, with 94.4%, 97.5% and 97.5%, respectively, retention per round. The dZ:dP pair appears to be lost principally via transition to a dC:dG pair. This is consistent with a mechanistic hypothesis that deprotonated dZ (presenting a pyDAA pattern) complements dG (presenting a puADD pattern), while protonated dC (presenting a pyDDA pattern) complements dP (presenting a puAAD pattern). This hypothesis, grounded in the Watson-Crick model for nucleobase pairing, was confirmed by studies of the pH-dependence of mismatching. The dZ:dP pair and these polymerases, should be useful in dynamic architectures for sequencing, molecular-, systems- and synthetic-biology.     

Correction of autoradiographic grain count in respect to precisely calculated background

Summary It was endeavored to find a criterion for significantly labeled cells in quantitative autoradiography. Measurements of the autoradiographic background were performed and it was found that: 1. the value of the background over the non-proliferating epithelial cells from an animal injected with ³H-thymidine is higher than over the same cells from animals not injected with an isotope, 2. the value of the background in emulsion over the tissue specimen is higher than away from the specimen. Therefore, one should take into account the background over the tissue. Nomograms are shown for quick evaluation of the percentage of cells labeled with 1, 2, 3 or 4 grains, which should be disregarded as due to the background. To obtain this percentage for a given experiment its appropriate parameters: the labeling index, the mean grain count over the cell, the standard deviation of the grain count distribution and the background grain count distribution should be taken into account.