Kinetic Process of β-Amyloid Formation via Membrane Binding

Recently we have studied thermodynamics of membrane-mediated β-amyloid formation in equilibrium experiments using penetratin-lipid mixtures. The results showed that penetratin bound to the membrane interface in the α-helical conformation when the peptide/lipid (P/L) ratios were below a lipid-dependent critical value P/L^∗. When P/L reached P/L^∗, small β-aggregates emerged, which served as the nuclei for large β-aggregates. Here we studied the corresponding kinetic process to understand the potential barriers for the membrane-mediated β-amyloid formation. We performed kinetic experiments using giant unilamellar vesicles made of 7:3 DOPC/DOPG. The observed time behavior of individual giant unilamellar vesicles, although complex, exhibited the physical effects seen in equilibrium experiments. Most interestingly, a potential barrier appeared to block penetratin from translocating across the bilayer. As a result, the kinetic value for the critical threshold P/L^∗ is roughly one-half of the value measured in equilibrium where peptides bind symmetrically on both sides of lipid bilayers. We also investigated the similarity and differences between the charged and neutral lipids in their interactions with penetratin. We reached an important conclusion that the bound states of peptides in lipid bilayers are largely independent of the charge on the lipid headgroups.     

Pattern analysis of stem cell differentiation during <Emphasis Type="Italic">in vitro Arabidopsis</Emphasis> organogenesis

Plant somatic cells have the capability to switch their cell fates from differentiated to undifferentiated status under proper culture conditions, which is designated as totipotency. As a result, plant cells can easily regenerate new tissues or organs from a wide variety of explants. However, the mechanism by which plant cells have such remarkable regeneration ability is still largely unknown. In this study, we used a set of meristem-specific marker genes to analyze the patterns of stem cell differentiation in the processes of somatic embryogenesis as well as shoot or root organogenesis in vitro. Our studies furnish preliminary and important information on the patterns of the de novo stem cell differentiation during various types of in vitro organogenesis.     

Intramuscular loading dose of quinine for falciparum malaria: pharmacokinetics and toxicity.

In a study of intramuscular injection of quinine eight adults with moderately severe falciparum malaria resistant to chloroquine were treated with quinine dihydrochloride, being given a loading dose of 20 mg salt (16.7 mg base)/kg followed by three or four eight hourly maintenance doses of 10 mg salt (8.3 mg base)/kg injected into the anterior thigh. All patients responded to treatment. Fever and parasite clearance times (mean (SD) 60 (23) h and 53 (22) h respectively) were comparable with those obtained with intravenous quinine. The mean peak plasma quinine concentration of 11.0 mg/l (34.4 mu mol/l) [corrected] was reached a median of five hours after administration of the loading dose. In all patients plasma quinine concentrations exceeded the high minimum inhibitory concentration for Plasmodium falciparum malaria prevalent in Thailand within four hours of the start of treatment but did not cause toxicity other than mild cinchonism. When intravenous infusion is not possible an intramuscular quinine loading dose is an effective means of starting treatment in patients with moderately severe falciparum malaria who cannot swallow tablets.     

Enhancement of cell growth by intracellularly expressed herpes simplex virus thymidine kinase

A recombinant cell line (NIH3T3:pLtkSN) was made by infecting parental cells (NIH3T3) with a recombinant retrovirus (pLtkSN) encoding herpes simplex virus thymidine kinase (HSVtk) gene. The cells expressing HSVtk (NIH3T3:pLtkSN) grew 2.3 times more than the parental cells (NIH3T3) in Dulbecco's Modified Eagles Media containing 10% (v/v) horse serum. The NIH3T3:pLtkSN cells also showed a significant enhancement in the maximal cell concentration and the specific growth rate even at 2.5% serum concentration. The specific O2 uptake rate of NIH3T3 was 2.1 times greater than that of NIH3T3:pLtkSN. Under both O2-limited and O2-unlimited conditions, it appears that HSVtk plays an important role in enhancing the growth characteristics of animal cells.     

A simple method using PCR for direct sequencing of genomic DNA from frozen tumor tissue embedded in optimal cutting temperature compound.

Described here is a three-day protocol that directly yields DNA sequence after isolating and PCR amplifying genomic DNA from a small sample of frozen nasopharyngeal carcinoma tissue embedded in optimal cutting temperature (OCT) compound. The method is consistently successful, reproducible and will facilitate the rapid analysis of DNA sequence from very small samples.     

Single-cell landscape of the ecosystem in early-relapse hepatocellular carcinoma

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A study on giant panda recognition based on images of a large proportion of captive pandas

1. As a highly endangered species, the giant panda (panda) has attracted significant attention in the past decades. Considerable efforts have been put on panda conservation and reproduction, offering the promising outcome of maintaining the population size of pandas. To evaluate the effectiveness of conservation and management strategies, recognizing individual pandas is critical. However, it remains a challenging task because the existing methods, such as traditional tracking method, discrimination method based on footprint identification, and molecular biology method, are invasive, inaccurate, expensive, or challenging to perform. The advances of imaging technologies have led to the wide applications of digital images and videos in panda conservation and management, which makes it possible for individual panda recognition in a noninvasive manner by using image‐based panda face recognition method.
2. In recent years, deep learning has achieved great success in the field of computer vision and pattern recognition. For panda face recognition, a fully automatic deep learning algorithm which consists of a sequence of deep neural networks (DNNs) used for panda face detection, segmentation, alignment, and identity prediction is developed in this study. To develop and evaluate the algorithm, the largest panda image dataset containing 6,441 images from 218 different pandas, which is 39.78% of captive pandas in the world, is established.
3. The algorithm achieved 96.27% accuracy in panda recognition and 100% accuracy in detection.
4. This study shows that panda faces can be used for panda recognition. It enables the use of the cameras installed in their habitat for monitoring their population and behavior. This noninvasive approach is much more cost‐effective than the approaches used in the previous panda surveys.