Sequence heterogeneity and anomalous electrophoretic mobility of kinetoplast minicircle DNA from Leishmania tarentolae

Several unit-length minicircles from the kinetoplast DNA of Leishmania tarentolae were cloned into pBR322 and into M13 phage vectors. The complete nucleotide sequences of three different partially homologous minicircles were obtained. The molecules contained a region of approx. 80% sequence homology extending for 160–270 bp and a region unique to each minicircle. A 14-mer was found to be conserved in all kinetoplast minicircle sequences reported to date. The frequency distributions of various minicircle sequence classes in L. tarentolae were obtained by quantitative gel electrophoresis and by examination of the “T ladder” patterns of minicircles randomly cloned into M13 at several sites. By these methods we could assign approx. 50% of the total minicircle DNA into a minimum of five sequence classes. A sequence-dependent polyacrylamide gel migration abnormality was observed with several minicircle fragments both cloned and uncloned. The abnormality was dependent on the presence of a portion of the conserved region of the minicircle.     

Evolutionary trends of the hairy-faceSaguinus in terms of the dental and cranial morphology

Shape variations in the dentition and the cranium were analyzed for sevenSaguinus forms of the hairy-face tamarin by applying the factor analysis method. The results obtained for the dental and cranial measurements were almost consistent with each other. The magnitude of the difference in shape factors between theS. nigricollis group and theS. midas group is appreciably larger than that between the former group and theS. mystax group. If the ancestral geographic centre of origin is postulated as being within the region which is inhabited by the livingS. nigricollis group, the morphological distances between any pairs of groups correlate well with the geographic distances between them. Concerning the dental and cranial morphologies, the physical changes in the three species group probably took place in two directions; that is, from theS. nigricollis group to theS. mystax group, and from theS. nigricollis group to theS. midas group. The forms belonging to each species group are more closely related to each other, with the exception ofS. imperator in theS. mystax group. The uniqueness ofS. imperator was clearly demonstrated by factor analysis and distance analysis. In theS. mystax group, although still hypothetical,S. imperator may have been related only through the basic ancestral stock toS. labiatus andS. mystax.     

Critical nuclear DNA size and distribution associated with S phase initiation

Using HeLa S-3 cells synchronized by selective detachment, in this paper we report a parallel study of nuclear morphology and autoradiography grain patterns between middle G₁ and middle S phases: Our results show two distinct [³H]-thymidine labeling patterns. The first “peripheral” labeling pattern has a characteristic nuclear size distribution, in contrast to the heterogeneous and varying size distributions of Feulgen-stained nuclei, and apparently is characteristic of very early S phase. The sizes of the second labeling pattern—homogeneous or inhomogeneous grain distribution throughout the nucleus—are equal or larger than the first and vary with S phase progression. Together, the corresponding nuclear sizes of the labeled nuclei represent the larger extreme of nuclear areas, and the labeling index closely parallels the fraction of nuclei with areas larger than the minimum size of the labeled nuclei. These results suggest a characteristic nuclear size (reflecting unique intranuclear DNA distribution) as a necessary, if not sufficient, requirement for S phase initiation. Parallel experimentation with rat liver cells—synchronized in vivo by partial hepatectomy and analyzed by thin section autoradiography—confirms the existence of a peripheral labeling pattern in both the very early part and the very late part of S phase, which reconciles our data with previous results and points to the fact that both initiation and termination sites for DNA replication are near the nuclear periphery.     

The araBAD operon of Salmonella typhimurium LT2. I. Nucleotide sequence of araB and primary structure of its product, ribulokinase

Hybrid plasmids containing the araBAD operon of Salmonella typhimurium LT2 were characterized by Southern blot and genetic analyses. The nucleotide sequence of araB was determined. The araB gene product, ribulokinase (EC 2.7.1.16), was purified and the results of amino acid composition analysis and partial amino acid sequence are in agreement with predictions from the DNA sequence. Ribulokinase is 569 amino acid residues long and has a calculated Mr of 61 793. Ribulokinase shares significant homology with xylulose kinase from Escherichia coli. Codon usage in the araB gene does not favor those codons which have intermediate codon-anticodon binding energy.     

Analysis of the inducible MEL1 gene of Saccharomyces carlsbergensis and its secreted product, alpha-galactosidase (melibiase)

We have determined both the nucleotide sequence of the MEL1 gene of Saccharomyces carlsbergensis and the N-terminal amino acid (aa) sequence of its extracellular gene product, alpha-galactosidase (melibiase) (alpha-Gal). The predicted translation product of MEL1 is a pre-alpha-Gal protein containing an 18 aa N-terminal signal sequence for secretion. The purified enzyme is a dimer consisting of two 50-kDal polypeptides, each of which is glycosylated with no more than eight side chains. The 5'-flank of the MEL1 gene contains a region (UASm) having certain areas of sequence homology to similar sites found upstream of the structural genes GAL1, GAL7 and GAL10, which are also regulated by the action of the products of genes GAL4 and GAL80. There are three TATA boxes between UASm and the initiation codon of pre-alpha-Gal, as well as a typical yeast cleavage/polyadenylation sequence in the 3'-flank of the gene.     

Pollen morphology of Solanurn L. section Solanum

J. M. EDMONDS, 1984. Pollen morphology of Solanum L. section Solnnum . The pollen morphology of both dried and fresh, fixed material was examined using SEM. The work confirmed thc spheroidal to sub-prolate shape, the tricolporate nature and the granular surface sculpturing, typical of Solanurn pollen, but failed to demonstrate the occurrence of exine patterns which could bc of practical taxonomic use is differentiating the species belonging to the section Solanurn . Quantification of the exine sculpturing, by means of granule density counts, indicated a possible relationship between this feature and the morpho-genetic diversity of certain species.     

Comparison of four molecular markers in measuring relationships among the wild potato relatives Solanum section Etuberosum (subgenus Potatoe)

We evaluated chloroplast DNA (cpDNA), isozymes, single to low-copy nuclear DNA (RFLPs), and random amplified polymorphic DNAs (RAPDs) in terms of concordance for genetic distance of 15 accessions each of Solanum etuberosum and S. palustre, and 4 accessions of S. fernandezianum. These self-compatible, diploid (2n=24), and morphologically very similar taxa constitute all species in Solanum sect. Etuberosum, a group of non-tuber-bearing species closely related to Solanum sect. Petota (the potato and its wild relatives). Genetic distance and multidimentional scaling results show general concordance of isozymes, RFLPs and RAPDs between all three taxa; cpDNA shows S. etuberosum and S. palustre to be more similar to each other than to S. fernandezianum. Interspecific sampling variance shows a gradation of resolution from allozyme (low) to RAPD to RFLP (high); while intraspecific comparisons graded from RFLPs (low) to RAPDs (high; lack of sufficient allozyme variability within species precluded comparisons for allozymes). Experimental error was low in RFLPs and RAPDs.Names are necessary to report factually and available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable     

MRI在剖宫产术后瘢痕妊娠诊疗路径中的应用价值

摘要 目的：探讨磁共振成像在剖宫产术后瘢痕妊娠（cesarean scar pregnancy,CSP）诊疗路径中的应用价值。方法：回顾性分析24例经手术和（或）病理证实为瘢痕妊娠的孕妇临床和影像检查资料,记录MRI上妊娠囊位置、大小、T1、T2信号强度、妊娠囊类型、妊娠囊与子宫前壁下段肌层及膀胱的关系,分析MR特征对临床诊疗路径的应用价值。结果：24例妊娠囊均位于子宫下段,为圆形或卵圆形,11例妊娠囊为单纯囊性,12例妊娠囊为混杂包块型,1例因清宫术后行MR,未见明确妊娠囊,仅见子宫下段混杂信号。10例妊娠囊附着处子宫肌厚度不可测量,余14例妊娠囊附着处子宫肌厚度约0.9～5.0 mm,平均2.5±1.1 mm。据此,CSP分型为I型5例,II型7例,III型12例。结论：MRI能较好的评估CSP, 在CSP诊疗路径中的应用价值较大。     

气压治疗仪联合那屈肝素预防剖宫产术后下肢静脉栓塞的临床研究

摘要 目的：探究气压治疗仪联合那屈肝素预防剖宫产术后下肢静脉栓塞（DVT）的临床效果。方法：选取2021年1月～2022年8月长沙市妇幼保健院收治的172例剖宫产孕妇,以随机数字表法按1:1比例分为联合组、常规组,各86例。常规组采用那屈肝素预治疗,联合组采用气压治疗仪联合那屈肝素治疗。比较两组DVT发生率;术前、术后5 d凝血功能指标[凝血酶时间（TT）、纤维蛋白原（FIB）、活化部分凝血活酶时间（APTT）、凝血酶原时间（PT）]、血液流变学指标[全血高切黏度、血浆黏度、全血低切黏度];术前、术后1 d、5 d大小腿腿围;术前、术后1 d、3 d、5 d疼痛视觉模拟量表（VAS）评分。结果：联合组DVT发生率3.49%较常规组11.63%低（P＜0.05）;术后5 d联合组PT、APTT、TT较常规组高,FIB较常规组低（P＜0.05）;术后5 d联合组全血高切黏度、血浆黏度、全血低切黏度较常规组低（P＜0.05）;术后1 d、5 d联合组大小腿腿围较常规组低（P＜0.05）;术后1 d、3 d、5 d联合组VAS评分较常规组低（P＜0.05）。结论：气压治疗仪联合那屈肝素能有效改善剖宫产产妇术后凝血功能及血液流变学,缓解下肢肿胀,减轻术后疼痛,减少DVT的发生。