Kinetics of protein-mediated transfer of rat pancreatic microsomal phosphatidylinositol to liposomes

Pancreatic microsomes were isolated from fasted and pilocarpine-injected rats and the microsomal phosphatidylinositol radiolabelled with myo-[2-³H]inositol by isotopic exchange. A standard reaction mixture was established in which partially purified rat liver phosphatidylinositol exchange proteins sustain a maximal rate of phosphatidylinositol transfer from rat pancreatic microsomes to liposomes. Determination of the transfer kinetics shows (1) that pancreatic microsomal phosphatidylinositol is partitioned approximately equally between a non-exchangeable and a single exchangeable pool and (2) that cholinergic stimulation does not significantly change the relative sizes of the two pools nor the exchange half-life of the latter pool.     

Covid-19 in end-stage renal disease patients with renal replacement therapies: A systematic review and meta-analysis

BackgroundThe novel coronavirus (COVID-19), caused by SARS-CoV-2, showed various prevalence and case-fatality rates (CFR) among patients with different pre-existing chronic conditions. End-stage renal disease (ESRD) patients with renal replacement therapy (RRT) might have a higher prevalence and CFR due to reduced immune function from uremia and kidney tropism of SARS-CoV-2, but there was a lack of systematic study on the infection and mortality of the SARS-CoV-2 infection in ESRD patients with various RRT.Methodology/Principal findingsWe searched five electronic databases and performed a systematic review and meta-analysis up to June 30, 2020, to evaluate the prevalence and case fatality rate (CFR) of the COVID-19 infection among ESRD patients with RRT. The global COVID-19 data were retrieved from the international database on June 30, 2020, for estimating the prevalence and CFR of the general population as referencing points. Of 3,272 potential studies, 34 were eligible studies consisted of 1,944 COVID-19 confirmed cases in 21,873 ESRD patients with RRT from 12 countries in four WHO regions. The overall pooled prevalence in ESRD patients with RRT was 3.10% [95% confidence interval (CI) 1.25–5.72] which was higher than referencing 0.14% global average prevalence. The overall estimated CFR of COVID-19 in ESRD patients with RRT was 18.06% (95% CI 14.09–22.32) which was higher than the global average at 4.98%.ConclusionsThis meta-analysis suggested high COVID-19 prevalence and CFR in ESRD patients with RRT. ESRD patients with RRT should have their specific protocol of COVID-19 prevention and treatment to mitigate excess cases and deaths.     

Unstable Lysogeny and Pseudolysogeny in Vibrio harveyi Siphovirus-Like Phage 1

Exposure of Vibrio harveyi (strain VH1114) to V. harveyi siphovirus-like phage 1 (VHS1) resulted in the production of a low percentage of lysogenized clones of variable stability. These were retrieved most easily as small colonies within dot plaques. Analysis revealed that VHS1 prophage was most likely carried by VH1114 as an episome rather than integrated into the host chromosome. In the late exponential growth phase, lysogenized VH1114 continuously produced VHS1 but also gave rise to a large number of cured progeny. The absence of phage DNA in the cured progeny was confirmed by the absence of VHS1 DNA in Southern blot and PCR assays. Curiously, these very stable, cured subclones did not show the parental phenotype of clear plaques with VHS1 but instead showed turbid plaques, both in overlaid lawns and in dot plaque assays. This phenotypic difference from the original parental isolate suggested that transient lysogeny by VHS1 had resulted in a stable genetic change in the cured clones. Such clones may be called pseudolysogens (i.e., false lysogens), since they have undergone transient lysogeny and have retained some resistance to full lytic phage development, despite the loss of viable or detectable prophage.     

Chromosomal evolution in naked catfishes (Bagridae,Siluriformes): A comparative chromosome mapping study

We analyzed the distribution of repetitive DNA sequences on the chromosomes of nine species of the Bagridae from Thailand, i.e., Hemibagrus filamentus; H. nemurus; H. wyckii; H. wyckioides; Mystus atrifasciatus; M. multiradiatus; M. mysticetus; M. bocourti and Pseudomystus siamensis. Two classes of microsatellites and one transposable element (TE) were mapped by fluorescence in situ hybridization. The distribution of the repetitive sequences was comparatively analyzed in view to investigate their contribution in the chromosomal evolution of this fish group. In all species the microsatellites (CA)₁₅ and (GA)₁₅ are abundantly distributed in all chromosomes, usually in the telomeric regions. The retrotransposable element Rex 1 is widely distributed over the whole genome including heterochromatin and euchromatin, but with an unexpected accumulation in one chromosome pair in some species. In fact, some species–specific patterns could be observed considering both microsatellites and TE distribution. The results demonstrated that the compartmentalization of repeated elements is not simply restricted to heterochromatic regions, as it has been postulated in the first concepts of the genomic organization of repetitive elements in genomes. Moreover, the organization of these repeats seems to reflect their intense and specific evolutionary pathway, providing new insights about the chromosomal evolution in the Bagridae.     

Synthesis and analysis of conformationally restricted analogs of peptide inhibitors of the angiotensin-converting enzyme

To investigate conformations of peptide inhibitors of the angiotensin-converting enzyme in the enzyme-inhibitor complex, the synthesis, studies of inhibitory activity, and conformational calculations of analogues of bradykinin-potentiating peptides with N-methylalanine or D-alanine in place of L-proline or L-alanine residues have been carried out. All the analogues showed a sharp decrease of inhibitory activity in comparison with the natural peptides, that might be considered as an indirect confirmation of the earlier proposed "conformation of inhibition" of the above-mentioned peptides.     

Regeneration of Pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.) by a cyclic organogenic system

In a five-step procedure, plants were regenerated from meristematic tissue initiated from nodal tissue in four pea cultivars (Espace, Classic, Solara, and Puget). In step 1, stem tissue with one node (1-cm size) was subcultured on medium containing thidiazuron. As a result multiple shoots were produced, appearing normal or swollen at their bases. The multiple shoots were subcultured in the same medium, resulting in the formation of a green hyperhydric tissue in the swollen bases of the multiple shoots, which is fully covered with small buds [bud-containing tissue (BCT)]. In step 2, BCT fragments were isolated and subcultured in the same medium and, as a result, they were able to reproduce themselves in a cyclic fashion. In step 3, subculture of BCT on medium supplemented with a combination of gibberelic acid, 6-benzyladenine and -naphthalene acetic acid (NAA), resulted in the formation of shoots, which were rooted in step 4 on medium supplemented with 0.5 mg/l NAA, indole-3-acetic acid (IAA) or indole-3-butyric acid. In step 5, in vitro plants were transferred to the greenhouse for acclimatisation and further development. The four varieties tested were all able to produce meristematic tissue, suggesting that its production is genotype independent.     

Transgene Organisation in Potato After Particle Bombardment-mediated (co-)Transformation Using Plasmids and Gene Cassettes

Protocols for efficient co-transformation of potato internodes with genes contained in separate plasmids or gene cassettes (i.e., linear PCR fragments comprising a promoter-gene-terminator) using particle bombardment were established. Twenty-eight out of 62 (45%) and 11 out of 65 (17%) plants transformed with a plasmid containing the selectable marker contained one and two additional non-selected genes, respectively. When gene cassettes were used in transformation, six out of eight plants were co-transformed. Expression analysis showed that 75–80% of the plants transformed with two transgenes expressed both of them, irrespective of the use of plasmids or gene cassettes. Thirty-eight plants containing the gusA reporter-gene and the nptII selectable-marker have been characterised with respect to the molecular organisation of the donor DNAs. Seventeen out of 49 (35%) gusA sites of integration contained one copy of the gene. Only 11 gusA sites (22%) were linked to the site of integration of the selectable marker. When one site of integration contained several copies of the transgene, a predominance of 3–3 inverted re-arrangement repeats was observed.     

Genetic transformation of Alstroemeria using particle bombardment

Transgenic plants were obtained after particle bombardment of embryogenic callus derived from stem segments of two tetraploid Alstroemeria genotypes with plasmids containing different selection/reporter genes. Firstly, a plasmid containing a firefly luciferase reporter gene driven by the maize ubiquitin promoter (Ubi1), was bombarded into both friable embryogenic callus and proembryos. Transient and stable expression of luciferase was visually detected by a luminometer. This selection method is non-destructive and can be applied over the whole developmental process from callus to embryo and plantlet. Molecular proof of transformation was obtained both by PCR analysis and Southern hybridization. Secondly, a plasmid containing the bar gene together with an uidA gene coding for -glucuronidase both driven by the Ubi1 promoter was bombarded into proembryos. The transgenic callus was effectively selected from the callus clumps four months after bombardment on a medium containing 5 mg/l phosphinotricin (PPT). Selection by PPT was efficient and labour-saving. Stable expression of GUS was confirmed by the histochemical staining assay and molecular proof was obtained by PCR analysis.