Site of synthesis of the mitochondrial cytochromes in hepatocyte cultures

The biosynthesis of mammalian mitochondrial cytochromes was explored in primary hepatocyte cultures. When these were pulsed with [35S]methionine in the presence of cycloheximide, eight discrete mitochondrial polypeptides were detected by fluorography after their resolution under denaturing conditions by polyacrylamide gel electrophoresis. Since the pulse labeling of the polypeptides was sensitive to chloramphenicol, an inhibitor of mitochondrial translation, they must be translated on mitochondrial ribosomes. Three were identified as the largest subunits of cytochrome oxidase by their immunoprecipitation with antibody directed against purified rat liver cytochrome oxidase. Another (Mr = 28,000) was identified as one of eight subunits of purified rat liver cytochrome b-c1 complex by its immunoprecipitation with antibody directed against bovine heart b-c1 complex. Since cytochrome b apoprotein is the only product of the mitochondrial genome in the yeast cytochrome b-c1 complex (Krieke, J., Bechmann, H., van Hemert, F. J., Schweyan, R. J., Boer, P. H., Kaudewitz, F., and Groot, G. S. P. (1979) Eur. J. Bio-chem. 101, 607-617), the results strongly suggest that the Mr = 28,000 subunit of liver b-c1 complex is cytochrome b apoprotein. Thus the contribution of the mitochondrial translation system to the cytochrome complexes in liver is identical to that of yeast and Neurospora, and there appears to be no deletion or transfer to the nuclear genome of structural genes for mitochondrially synthesized cytochromes during eukaryotic evolution.     

The fine structure of the vesicular component of the ultimobranchial gland of the domestic fowl

Summary The ultrastructure of the polymorphic vesicular component of the ultimobranchial gland of the domestic fowl (Gallus gallus domesticus) has been described in detail, together with the structure of the cell strands interconnecting the vesicles and the parathyroid nodules lying within the ultimobranchial stroma. The vesicles frequently appear to arise from the nodules by way of the cell strands. The strands show a structure of their component cells intermediate between that of the parathyroid and the vesicular cells, although the position at which the strand changes from an essentially parathyroid structure to an essentially vesicular structure is very variable. The degree and kind of secretory activity within different cell types has been described. A review of the structure of ultimobranchial glands throughout the vertebrates shows that similar tissue with a similar secretory potential has been observed in all vertebrate classes, suggesting a functional significance for this part of the gland.     

Yield of 1,6-anhydro-3,4-dideoxy-β-d-glycero-hex-3-enopyranos-2-ulose (levoglucosenone) on the acid-catalyzed pyrolysis of cellulose and 1,6-anhydro-β-d-glucopyranose (levoglucosan)

Although 1,6-anhydro-3,4-dideoxy-,β-d-glycero-hex-3-enopyranos-2-ulose (2) is produced by the acid-catalyzed pyrolysis of both cellulose and 1,6-anhydro-β-d-glucopyranose (1), data presented here show that the principal mechanism of its formation in the pyrolysis of cellulose is not via 1. Furthermore, the data provide evidence that 1 itself is not a primary product of cellulose pyrolysis, so that the principal mechanism of its formation must involve a precursor as yet unidentified.     

In-Vitro and In-Vivo Effects of Aldicarb on Survival and Development of Heterodera schachtii

Aqueous solutions of 5-500 μg/ml aldicarb inhibited hatching of Heterodera schachtii. Addition of hatching agents, zinc chloride, or sugarbeet root diffusate, to the aldicarb solutions did not decrease the inhibition of hatching. When cysts were removed from the aldicarb solufions and then treated for 4 wk in sugarbeet root diffusate, larvae hatched and emerged. Treatments of newly hatched larvae of H. schachtii with 5-100 μg/ml aldicarb depressed later development of larvae on sugarbeet (Beta vulgaris). Similar treatments with aldicarb sulfoxide had less effect on larval development, and aldicarb sulfone had no effect. Numbers of treated larvae that survived and developed were inversely proportional to concentration (0.1-5.0 μg/ml) and duration (0-14 days) of aldicarb treatments. Development of H. schachtii on sugarbeet grown in aldicarb-treated soil was inversely proportional to the concentration of aldicarb in the tested range of 0.75 - 3.0 μg aldicarb/g of soil. Transfer of nematode-infected plants to soil with aldicarb retarded nematode development, whereas transfer of plants first grownin treated soil to nematode-infested soil only slightly suppressed nematode development. Development of H. schachtii was inhibited in slices of storage roots of table beet (B. vulgaris), sugarbeet and turnip, (Brassica rapa), that had grown in soil treated with aldicarb.     

Plasma membrane adenosine triphosphatase of oat roots: activation and inhibition by mg and ATP

ATPase activity of plasma membrane vesicles isolated from oat (Avena sativa L. cv. Goodfield) roots was examined in the presence of various concentrations of MgCl(2) and ATP. A Mg(2+): ATP ratio of about 1 was required for maximal activity regardless of the concentrations used; the optimum concentration for both Mg(2+) and ATP was 9 mm. Based on the ATPase activity at different concentrations of complexed Mg.ATP and free ATP, it is concluded that Mg.ATP is the true substrate of this enzyme.Under certain experimental conditions, high concentrations of MgCl(2) and ATP inhibited the plasma membrane ATPase. On the basis of the relative amounts of free and complexed ATP and Mg(2+), it was found that the different moieties caused different amounts of inhibition. Free ATP inhibited the ATPase at concentrations in excess of 2 mm. Mg.ATP concentrations above 11 mm inhibited the enzyme. Free Mg(2+) caused only a slight inhibition of the ATPase.The Km for Mg.ATP was found to vary from 0.64 to 1.24 mm depending on the experimental conditions. This variation is thought to be due to variable amounts of Mg.ATP, which serves as an inhibitor as well as the substrate, and free ATP, which also inhibits the enzyme.     

Comparative total and proportional rate of germination of Bipolaris sorokiniana and Curvularia geniculata conidia is influenced by culture age and temperature

Comparative observations of Bipolaris sorokiniana and Curvularia geniculata conidia germination as influenced by culture age and temperature showed some distinct differences, but generally established the ability of these organisms to function under similar conditions. Total germination of B. sorokiniana conidia was favored by increasing culture age from 20 to 60 days and temperature to 25°C; total conidia germination of C. geniculata was favored by increasing temperature to 25°C, but increasing culture age decreased germination. These reactions seem associated with conidia age. Maximum proportional intra-population germination of conidia of each organism also varied with culture age and temperature. At temperatures of 5°C and 15°C, amplitude of maximum proportional germination of both organisms increased as culture age was increased from 20 to 40 days and then decreased among 60-day-old cultures. At 25°C and above, amplitude of maximum proportional germination of conidia of both organisms decreased from each older culture. Progressively increasing temperature at a given culture age increased the amplitude of maximum proportional germination up to 25°C for conidia of B. sorokiniana, but generally decreased it for conidia of C. geniculata (except 20-day-old cultures). Frequency (specific 2 h interval) of maximum proportional intrapopulation germination of B. sorokiniana shifted from 6 h to 2 h in response to increasing temperature and culture age; conidia from youngest cultures of C. geniculata shifted to intervals of 4 h and 2 h in response to increasing temperature to 25°C, but among conidia from 60-day-old cultures, frequency shifted to 6 h intervals at all temperatures. Above 25°C, maximum proportional germination of C. geniculata conidia from cultures of all ages occurred at 6 h. It was concluded that the germination response of B. sorokiniana and C. geniculata conidia to temperature and culture age (and, subsequently, conidia age) are enough similar that these organisms could function in a potential ‘disease complex’ on Poa pratensis and Agrostis palustris.     

A survey of nuclear ribosomal internal transcribed spacer substitution rates across angiosperms: an approximate molecular clock with life history effects

Background  

A full understanding of the patterns and processes of biological diversification requires the dating of evolutionary events, yet the fossil record is inadequate for most lineages under study. Alternatively, a molecular clock approach, in which DNA or amino acid substitution rates are calibrated with fossils or geological/climatic events, can provide indirect estimates of clade ages and diversification rates. The utility of this approach depends on the rate constancy of molecular evolution at a genetic locus across time and across lineages. Although the nuclear ribosomal internal transcribed spacer region (nrITS) is increasingly being used to infer clade ages in plants, little is known about the sources or magnitude of variation in its substitution rate. Here, we systematically review the literature to assess substitution rate variation in nrITS among angiosperms, and we evaluate possible correlates of the variation.     

High‐throughput analysis of vocalizations reveals sex‐specific changes in Fmr1 mutant pups

There have been several reports that individuals with Fragile X syndrome (FXS) and animal models of FXS have communication deficits. The present study utilized two different call classification taxonomies to examine the sex‐specificity of ultrasonic vocalization (USV) production on postnatal day (PD8) in the FVB strain of Fmr1 knockout (KO) mice. One classification protocol requires the investigator to score each call by hand, while the other protocol uses an automated algorithm. Results using the hand‐scoring protocol indicated that male Fmr1 KO mice exhibited longer calls (P = .03) than wild types on PD8. Male KOs also produced fewer complex, composite, downward, short and two‐syllable call‐types, as well as more frequency steps and chevron call‐types. Female heterozygotes exhibited no significant changes in acoustic or temporal aspects of calls, yet showed significant changes in call‐type production proportions across two different classification taxonomies (P < .001). They exhibited increased production of harmonic and frequency steps calls, as well as fewer chevron, downward and short calls. According to the second high‐throughput analysis, female heterozygotes produced significantly fewer single‐type and more multiple‐type syllables, unlike male KOs that showed no changes in these aspects of syllable production. Finally, we correlated both scoring methods and found a high level of correlation between the two methods. These results contribute further knowledge of sex differences in USV calling behavior for Fmr1 heterozygote and KO mice and provide a foundation for the use of high‐throughput analysis of neonatal USVs.     

Achievements and challenges of lymphatic filariasis elimination in Sierra Leone

BackgroundLymphatic filariasis (LF) is targeted for elimination in Sierra Leone. Epidemiological coverage of mass drug administration (MDA) with ivermectin and albendazole had been reported >65% in all 12 districts annually. Eight districts qualified to implement transmission assessment survey (TAS) in 2013 but were deferred until 2017 due to the Ebola outbreak (2014–2016). In 2017, four districts qualified for conducting a repeat pre-TAS after completing three more rounds of MDA and the final two districts were also eligible to implement a pre-TAS.Methodology/Principal findingsFor TAS, eight districts were surveyed as four evaluation units (EU). A school-based survey was conducted in children aged 6–7 years from 30 clusters per EU. For pre-TAS, one sentinel and one spot check site per district (with 2 spot check sites in Bombali) were selected and 300–350 persons aged 5 years and above were selected. For both surveys, finger prick blood samples were tested using the Filariasis Test Strips (FTS).For TAS, 7,143 children aged 6–7 years were surveyed across four EUs, and positives were found in three EUs, all below the critical cut-off value for each EU. For the repeat pre-TAS/pre-TAS, 3,994 persons over five years of age were surveyed. The Western Area Urban had FTS prevalence of 0.7% in two sites and qualified for TAS, while other five districts had sites with antigenemia prevalence >2%: 9.1–25.9% in Bombali, 7.5–19.4% in Koinadugu, 6.1–2.9% in Kailahun, 1.3–2.3% in Kenema and 1.7% - 3.7% in Western Area Rural.Conclusions/SignificanceEight districts in Sierra Leone have successfully passed TAS1 and stopped MDA, with one more district qualified for conducting TAS1, a significant progress towards LF elimination. However, great challenges exist in eliminating LF from the whole country with repeated failure of pre-TAS in border districts. Effort needs to be intensified to achieve LF elimination.     

构建基于CRISPR/Cas9技术敲除ALOX5的质粒

旨在利用CRISPR/Cas9技术构建敲除花生四烯5-脂氧合酶基因(Arachidonate 5-lipoxygenase gene,ALOX5)的重组质粒。设计合成3对靶向敲除ALOX5第六外显子的sgRNA,将其分别插入到CRISPR/Cas9质粒骨架pX458载体中,转化感受态大肠杆菌DH5α后挑取克隆,通过测序评估重组质粒是否构建成功。将构建好的重组质粒转染293T细胞,在荧光显微镜下观察转染效果,挑取转染成功的细胞,用试剂盒提取转染细胞基因组DNA,PCR扩增含敲除位点的DNA片段,用测序技术获得核苷酸序列,用DNAStar软件分析转染细胞中ALOX5基因敲除情况。测序结果表明2对双链sgRNA寡核苷酸已插入质粒,且序列正确,靶向ALOX5基因的重组质粒pX458-sgRNAs-ALOX5构建成功。其在293T细胞中的转染效率约为50%,用一代测序法未检测到sgRNAs的切割效果。初步表明利用CRISPR/Cas9技术成功构建靶向ALOX5基因的重组质粒pX458-sgRNAs-ALOX5。