Sexual dimorphism of blood pressure: Possible role of the renin-angiotensin system

The prevalence of hypertension in men is higher than in women and the onset of this disease is earlier in male than in female subjects. In spontaneously hypertensive rats, males also have higher blood pressures than females. Evidence from epidemiological, physiological, molecular biological and morphological studies concerning this sexual dimorphism is reviewed. We demonstrate that the gonadal steroids testosterone and estrogen have important effects on the gene regulation of the renin-angiotensin system. This may in part contribute to the sexual dimorphism in blood pressure control. The direct effect of steroid hormones on genes related to hypertension provides a suitable paradigm to improve our understanding of molecular and cellular mechanisms of cardiovascular control.     

Optimizing the production of transformed pea (Pisum sativum L.) callus using disarmed Agrobacterium tumefaciens strains

For optimization of the transformation procedure with Pisum sativum L. stern explant callus was used to test the effect of disarmed Agrobacterium tumefaciens strains, cocultivation procedures (preconditioning of explants; use of Nicotiana tabacum L. nurse cultures), duration of cocultivation (2, 3 or 4 days), and agents for selection (kanamycin or hygromycin). The succinamopine strain EHA101(pBI1042) produced the highest percentage of transformed calli (77%) when used in conjunction with tobacco nurse culture during four days of cocultivation. Using this strain, kanamycin (76%) and hygromycin (77%) were equally effective selective agents, but for strain LBA4404(pBI1042) percentage of transformed calli was higher for hygromycin (63%) than for kanamycin (17%). The procedures and strains shown to be optimal for transformation of pea callus will now be complemented by a pea regeneration system.     

Interferon-γ activates the cleavage of double-stranded RNA by bovine seminal ribonuclease

Bovine seminal ribonuclease (BS-RNase), a dimeric homologue of RNase A, cleaves both single- and double-stranded RNA and inhibits the growth of tumor cells. Its catalytic activity against double-stranded RNA, either homopolymeric ([³H]polyA/polyU) or mixed sequence, is enhanced by bovine or human recombinant interferon-γ (IFN-γ). Activation is seen with as little as 4–10 interferon units per assay. Enhancing the degradation of double-stranded RNA, an intermediate in the growth cycle of many viruses, could contribute to IFN-γ's ability to control cell growth and induce an antiviral state.     

A flow cytometric study of chromosomes from rat kangaroo and chinese hamster cells

Summary Chromosomes from rat kangaroo (PTK) and chinese hamster (CHV 79) cells have been prepared for quantitative flow-cytometric analysis. The preparation time was optimized down to 30 (PTK) and 40 min (CHV 79). DAPI was used as a AT-sensitive fluorescent dye to stain for monoparameter DNA measurements. Simultaneous two-parameter DNA-protein analysis was carried out with DAPI and SR 101 (as a general protein fluorochrome) in combination. The karyotype of the PTK cells with 13 (14) chromosomes was separated into 10 DNA peaks. The X-chromosome bearing the nucleolus organizer region generates a distinct peak. The karyotype of the CHV 79 cells with 22 chromosomes was separated into 15 peaks. The DNA profile obtained indicates a geometric grading of the chromosomal amount of AT components in the karyotype of this particular cell line. The simultaneous DNA-protein analysis performed show enough sensitivity of the instrument utilizing high power UV excitation illumination to discriminate the two color emission consisting of blue (DAPI) and red (SR 101) fluorescence. Color overlapping could be completely avoided. Additionally, the quality (number, location, and resolution of peaks) of the DNA distribution was not influenced by the simultaneous application of a second fluorescent stain. Fluorescence activated electronic sorting applied on chromosomal fluorescence distributions providing purified fractions of chromosomes for subsequent biochemical and biological determinations is discussed.     

A new family of CRISPR‐type V nucleases with C‐rich PAM recognition

Most CRISPR‐type V nucleases are stimulated to cleave double‐stranded (ds) DNA targets by a T‐rich PAM, which restricts their targeting range. Here, we identify and characterize a new family of type V RNA‐guided nuclease, Cas12l, that exclusively recognizes a C‐rich (5''‐CCY‐3′) PAM. The organization of genes within its CRISPR locus is similar to type II‐B CRISPR‐Cas9 systems, but both sequence analysis and functional studies establish it as a new family of type V effector. Biochemical experiments show that Cas12l nucleases function optimally between 37 and 52°C, depending on the ortholog, and preferentially cut supercoiled DNA. Like other type V nucleases, it exhibits collateral nonspecific ssDNA and ssRNA cleavage activity that is triggered by ssDNA or dsDNA target recognition. Finally, we show that one family member, Asp2Cas12l, functions in a heterologous cellular environment, altogether, suggesting that this new group of CRISPR‐associated nucleases may be harnessed as genome editing reagents.     

Phylogeny of calcareous dinoflagellates as inferred from ITS and ribosomal sequence data

The phylogenetic relationships of calcareous dinoflagellates (i.e., Calciodinellaceae and Thoracosphaera) are investigated. Molecular data from the ribosomal 5.8S rRNA and highly conserved motifs of the ITS1 show Calciodinellaceae s.l. to be monophyletic when few non-calcareous taxa are included. They segregate into three monophyletic assemblages in a molecular analysis that considers the 5.8S rRNA and both the Internal Transcribed Spacer regions ITS1 and ITS2: a clade comprising species of Ensiculifera and Pentapharsodinium (E/P-clade), Scrippsiella s.l. (including fossil-based taxa such as Calciodinellum and Calcigonellum), and a heterogeneous group (T/P-clade) of calcareous (e.g., Thoracosphaera) and non-calcareous taxa (e.g., the highly toxic Pfiesteria). The potential to produce calcareous structures is considered as apomorphic within alveolates, and non-calcareous taxa nesting with calcareous dinoflagellates may have reduced calcification secondarily. Molecular results do not contradict general evolutionary scenarios provided by previous morphological (mainly paleontological) investigations.