Replication of bacteriophage T4 DNA in vitro. I. Basic properties of the system.

A new in vitro system for T4 DNA replication was developed by concentrating cell lysates on cellophane disks. The time course of [3H]dTTP incorporation into DNA by the system was separated into two phases: one was a very rapid incorporation which was terminated within 2 min (phase I reaction), and the other was a slow but continuous incorporation thereafter (phase II reaction). More than half of the phase I reaction product was Escherichia coli DNA, but the phase II reaction was mostly T4 DNA. Phase II reaction required four deoxyribonucleoside triphosphates, ATP, Mg2+, and KCl. 5-Hydroxymethyldeoxycytidine triphosphate was essential for the reaction and not substitutable by dCTP. The presence of KCN or NaN3 in the reaction mixture did not interfere with [3H]dTTP incorporation, but the addition of deoxyribonuclease completely degraded the system. Alkaline sucrose sedimentation analysis of phage II reaction product revealed that phase II reaction proceeded by the discontinuous mode of DNA replication as in vivo. After T4 infection, the activity for phase II reaction appeared in parallel with the activity of T4 phage DNA replication in vivo.     

Plant growth regulators and Axl and immune checkpoint inhibitors from the edible mushroom Leucopaxillus giganteus

ABSTRACT

A novel compound, (R)-4-ethoxy-2-hydroxy-4-oxobutanoic acid (1), and six known compounds (2–7) were isolated from the fruiting bodies of the wild edible mushroom Leucopaxillus giganteus. The planar structure of 1 was determined by the interpretation of spectroscopic data analysis. The absolute configuration of 1 was determined by comparing specific rotation of the synthetic compounds. In the plant regulatory assay, the isolated compounds (1–7) and the chemically prepared compounds (8–10) were evaluated their biological activity against the lettuce (Lactuca sativa) growth. Compounds 1 and 3–10 showed the significant regulatory activity of lettuce growth. 1 showed the strongest inhibition activity among the all the compounds tested. In the lung cancer assay, all the compounds were assessed the mRNA expression of Axl and immune checkpoints (PD-L1, PD-L2) in the human A549 alveolar epithelial cell line by RT-PCR. Compounds 1–10 showed significant inhibition activity against Axl and/or immune checkpoint.     

Functional activity of RLIM/Rnf12 is regulated by phosphorylation-dependent nucleocytoplasmic shuttling

The X-linked gene Rnf12 encodes the ubiquitin ligase really interesting new gene (RING) finger LIM domain–interacting protein (RLIM)/RING finger protein 12 (Rnf12), which serves as a major sex-specific epigenetic regulator of female mouse nurturing tissues. Early during embryogenesis, RLIM/Rnf12 expressed from the maternal allele is crucial for the development of extraembryonic trophoblast cells. In contrast, in mammary glands of pregnant and lactating adult females RLIM/Rnf12 expressed from the paternal allele functions as a critical survival factor for milk-producing alveolar cells. Although RLIM/Rnf12 is detected mostly in the nucleus, little is known about how and in which cellular compartment(s) RLIM/Rnf12 mediates its biological functions. Here we demonstrate that RLIM/Rnf12 protein shuttles between nucleus and cytoplasm and this is regulated by phosphorylation of serine S214 located within its nuclear localization sequence. We show that shuttling is important for RLIM to exert its biological functions, as alveolar cell survival activity is inhibited in cells expressing shuttling-deficient nuclear or cytoplasmic RLIM/Rnf12. Thus regulated nucleocytoplasmic shuttling of RLIM/Rnf12 coordinates cellular compartments during mammary alveolar cell survival.     

Comparison of the host-handling behavior of Eretmocerus mundus on Bemisia tabaci B biotype, Q biotype and Trialeurodes vaporariorum

Host-handling behaviors of Eretmocerus mundus (Mercet) (Hymenoptera: Aphelinidae) toward first to fourth instar nymphs of the Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) B and Q biotypes and of Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae) were compared under laboratory conditions. The host acceptance rates differed among host stages but not among host species or biotypes. In all host species and biotypes, the parasitoids stopped their host-handling behavior before oviposition more often with older hosts. The total host-handling time was longer for the fourth instars than for younger instars, mainly due to the longer oviposition times and probing times. E. mundus showed marking behavior for the B. tabaci B and Q biotypes, but not for T. vaporariorum. In conclusion, E. mundus could parasitize all whitefly biotypes and species used in this study, but both B. tabaci biotypes were more suitable hosts than T. vaporariorum. The younger instars were good oviposition targets in all hosts.     

Epidemiological Characterization of Influenza A(H1N1)pdm09 Cases from 2009 to 2010 in Baguio City,the Philippines

Background

Baguio City, Philippines experienced its first influenza A(H1N1)pdm09 [A(H1)pdm09] case in May 2009. In spite of numerous reports describing the epidemiological and clinical features of A(H1)pdm09 cases, there are no studies about A(H1)pdm09 epidemiology in the Philippines, where year-round influenza activity was observed.

Objectives

We aimed to investigate the epidemiological and clinical features of A(H1)pdm09 in pandemic and post-pandemic periods.

Methods

Data were collected under enhanced surveillance of influenza-like illness (ILI) and severe acute respiratory infection (SARI) from January 2009 to December 2010. RT-PCR was used to detect A(H1)pdm09, following the protocol of the United States Centers for Disease Control and Prevention. The reproduction number was computed as a simple exponential growth rate. Differences in proportional and categorical data were examined using chi-square test or Fishers’ exact test.

Results and Conclusions

The outbreak was observed from week 25 to 35 in 2009 and from week 24 to 37 in 2010. The highest proportion of cases was among children aged 5–14 years. The number of ILI outpatients was 2.3-fold higher in 2009 than in 2010, while the number of inpatients was 1.8-fold higher in 2009. No significant difference in gender was observed during the two periods. The clinical condition of all patients was generally mild and self-limiting, with only 2 mortalities among inpatients in 2009. The basic reproduction number was estimated as 1.16 in 2009 and 1.05 in 2010 in the assumption of mean generation time as 2.6 days. School children played a significant role in facilitating influenza transmission.     

Bursty Communication Patterns Facilitate Spreading in a Threshold-Based Epidemic Dynamics

Records of social interactions provide us with new sources of data for understanding how interaction patterns affect collective dynamics. Such human activity patterns are often bursty, i.e., they consist of short periods of intense activity followed by long periods of silence. This burstiness has been shown to affect spreading phenomena; it accelerates epidemic spreading in some cases and slows it down in other cases. We investigate a model of history-dependent contagion. In our model, repeated interactions between susceptible and infected individuals in a short period of time is needed for a susceptible individual to contract infection. We carry out numerical simulations on real temporal network data to find that bursty activity patterns facilitate epidemic spreading in our model.