Delayed luminescence of Prorocentrum minimum under controlled conditions

Delayed luminescence (DL), also termed delayed fluorescence or delayed light emission, is the phenomenon of long-lived light emission by plants and cyanobacteria after being illuminated with light and put into darkness. Culture growth of three Prorocentrum minimum strains was studied with DL measurements. DL decay kinetics was measured from 1–60 s after a pulse of white light. The strains used were from the Adriatic Sea (PmK), from Chesapeake Bay, USA (D5), and from the Baltic Sea (BAL), cultured at salinity of 32, 16, and 8 (practical salinity scale), respectively. The strains differed in cell size and chlorophyll a content (PmK > D5 > BAL), as well as in DL parameters. The DL results were compared to standard measurements of culture density and carbon content (calculated from biovolumes). DL decay curves had a specific peak, which changed with culture growth and showed more similarities between the strains PmK and D5. The DL intensity increased with cell density and carbon content in a two-stage process, corresponding to the lag and exponential phases of growth. DL intensity was best correlated with carbon content irrespective of strain and is proposed as an estimate of biomass and for differentiating between lag and exponential phases of growth.     

DNA-based sputum cell image analysis for lung cancer in a clinical setting

OBJECTIVE: To measure cell nuclei characteristics, previously reported to express probability for lung cancer, in subjects with different forms ofpulmonary disease and those without disease. STUDY DESIGN: Sputum and buccal cell samples were obtained from 846 patients without pulmonary disease, with nonmalignant disease, chronic obstructive pulmonary disease, asbestosis and lung cancer, stained for DNA, scanned by cytometer and scored. This was related to specificity and sensitivity for lung cancer. At score 4.5 sensitivity was 53.8% and specificity 70.9%. This score and higher were defined as high scores (HS) and used to compare groups with lung cancer and other pulmonary disease. RESULTS: Among subjects without disease, 21.1% had HS in sputum cells. Among those with nonmalignant pulmonary disease, 31.7% had HS, and among subjects with lung cancer, 53.8% had it. Repeated evaluations showed that about one third of those with HS on the first occasion were normal on repeat sampling. Among subjects without lung cancer, 33.8% of never-smokers had sputum cell HS compared to 22.7.2% among smokers. CONCLUSION: Results demonstrate that the DNA cellular characteristics on cytometry were more frequent among subjects with lung cancer but also among subjects with other pulmonary disease compared to subjects witbout pulmonary disease.     

On the PBB Designs for Multiresponse Experiments

We present the idea of using multiresponse incomplete block designs when not all responses can be observed in all experimental units. For a special class of such designs, in which partial designs are PBB designs, a method for estimating natural treatment contrast is given. We also consider the problem of testing the hypotheses concerning the natural and any estimable treatment contrasts. For testing this hypothesis the Wald statistics, being asymptotically chi-square distributed, is proposed.     

Maturation and persistence of the anti-SARS-CoV-2 memory B cell response

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The flexibility of low molecular weight double-stranded dna as a function of length: II. Light scattering measurements and the estimation of persistence lengths from light scattering,sedimentation and viscosity

In the preceding paper are described the isolation and physical characterization of seven narrowly disperse fractions of calf thymus DNA in the molecular weight range 0.3 to 1.3 × 10⁶ daltons. Herein, we have determined by light scattering the molecular weights and root mean square radii of these fractions in a solvent comprising 0.2 M NaCl, 2 mM EDTA, 2m MNa-PO₄, pH 7. Measurements were made in a modified Wippler—Scheibling photometer to a 20° lower limit of scattering angle on solutions rendered virtually dust-free by procedures described. The optical aniso tropics of the DNA fractions were measured permitting the experimental molecular weights and root mean square radii to be corrected to their true values. From these values, with appropriate polydispersity corrections, we calculate a Kratky—Porod persistence length, a, of 54.0 ± 5.6 nm which is invariant over the molecular weight range examined. From the sedimentation coefficients (preceding paper) and the theory of Yamakawa and Fujii, we calculate a to be 66 nm, a value found to apply equally well to several DNA samples of various origins whose sedimentation rates are known in the molecular weight range from about 4 × 10⁴ to 10⁸ daltons. Similarly, from the intrinsic viscosities and the theory of Yamakawa and Fujii, we calculate a to be 59 nm, which again adequately applies to a number of DNA samples whose viscosities have been measured by other workers in the molecular weight range 3 × 10⁵ to 10⁸ daltons. The Flory—Mandelkern parameter, β, was found to vary with molecular weight in the manner predicted by the theory of Yamakawa and Fujii. The average value of a from the three sets of measurements is 60 ± 6 nm, which we believe applies to double-stranded DNA molecules, independent of chain length, over the whole range of molecular weights for which reliable data exist.     

On the E-Optimality of Block Designs with Unequal Block Sizes

In this paper an inequality for the smallest positive eigenvalues of the C-matrix of a block design are derived. This inequality is a generalization of a result by Constantine (1982) to the case of unequal block sizes. On the basis of the above result a certain E-optimality criterium of block designs is given. Furthermore coefficient e_d has been introduced which permits to assess how close the block design is from the optimal one.     

<Emphasis Type="Italic">Apodemus</Emphasis> mice as the main prey that determines reproductive output of tawny owl (<Emphasis Type="Italic">Strix aluco</Emphasis>) in Central Europe

During the years 2008–2014, we studied diet composition, the number of breeding pairs, and reproductive output of tawny owls in Central Europe (Czech Republic) in relation to availability of main prey in the field. We also performed a meta-analysis on diet composition of tawny owl in Europe that confirmed the important role of Apodemus mice in tawny owl diet in Central Europe. In concordance, Apodemus mice were the main prey of tawny owl in our study area (38.7%), and Microtus/Myodes voles (15.4%), birds (12.1%) and others (33.8%) were alternative prey. We found a positive relationship between the proportion of Apodemus mice in the diet and their abundance in the field (beta = 0.23, P = 0.001). Availability of main prey (Apodemus mice, Microtus/Myodes voles or Sorex shrews) in the field was not correlated with the number of breeding pairs. Proportion of birds in diet (expressed by scores from multivariate analysis), which was inversely related to proportion of Apodemus mice, was positively correlated with laying date (beta = 0.66, P = 0.012) and negatively correlated with clutch size (beta = − 0.45, P = 0.004) and brood size (beta = − 0.16, P = 0.076). We also found negative relationships between laying date and clutch size (beta = − 0.13, P = 0.014) and brood size (beta = − 0.07, P = 0.057). Our results support the idea that diet and breeding ecology of owls in Central Europe is mainly driven by the availability of Apodemus mice that are suitable prey due to their similar habitat requirements and nocturnal activity.     

Degradative covalent reactions important to protein stability

Commonly observed chemical modifications that occur in proteins during their in vitro purification, storage, and handling are discussed. Covalent modifications described include deamidation and isoaspartate formation, cleavage of peptide bonds at aspartic acid residues, cystine destruction and thioldisulfide interchange, oxidation of cysteine and methionine residues, and the glycation and carbamylation of amino groups.