EF-G-induced ribosome sliding along the noncoding mRNA.

Translational bypassing is a recoding event during which ribosomes slide over a noncoding region of the messenger RNA (mRNA) to synthesize one protein from two discontinuous reading frames. Structures in the mRNA orchestrate forward movement of the ribosome, but what causes ribosomes to start sliding remains unclear. Here, we show that elongation factor G (EF-G) triggers ribosome take-off by a pseudotranslocation event using a small mRNA stem-loop as an A-site transfer RNA mimic and requires hydrolysis of about two molecules of guanosine 5'-triphosphate per nucleotide of the noncoding gap. Bypassing ribosomes adopt a hyper-rotated conformation, also observed with ribosomes stalled by the SecM sequence, suggesting common ribosome dynamics during translation stalling. Our results demonstrate a new function of EF-G in promoting ribosome sliding along the mRNA, in contrast to codon-wise ribosome movement during canonical translation, and suggest a mechanism by which ribosomes could traverse untranslated parts of mRNAs.

[Research progress of maternal immunization].

Maternal immunization is an immune strategy that protects both mothers and early-life infants from disease by the vaccination of pregnant women. The effect of maternal immunization is influenced by the types of vaccines, the timing of vaccination, the subtypes of antibodies induced by vaccines, and the health status of mothers themselves. Inactivated influenza vaccination during pregnancy and DPT vaccination during the third trimester of pregnancy have been widely used in the world, while Hepatitis B vaccine, pneumococcal and meningococcal vaccines also show good efficacy and safety in pregnant women. This article reviews the research progress of Maternal Immunization in order to provide a reference for Maternal Immunization planning and policymaking in China.

[Research progress in immunization status and immunization effect of preterm infants].

Due to immature development of the immune system, preterm infants are at increased risk of infections from vaccine-preventable diseases. But at the same time, premature vaccination may not induce a good immune response because of the incomplete development of the neonatal immune system, and may cause serious adverse reactions risk due to the poor immune tolerance, thus vaccination of preterm infants at the appropriate time is the key to reducing the risk of infectious disease and obtaining vaccine protection. At present, it is generally recommended that the gestational age and birth weight should be considered in the vaccination of preterm infants. The timing, type and even the immunization schedule of the vaccine should be differ from that of the full term infants. However, there is a lack of research results and data on immunization program in preterm infants in China, and there is still no provided universal guidelines for their vaccine immunization. This article aims to summarize the guidelines and clinical trials of vaccination of preterm infants in foreign countries, and to provide reference for the formulation and implementation of immunization strategies for preterm infants in China.

Hydrate film growth on the surface of a gas bubble suspended in water.

The lateral film growth rate of CH4, C2H4, CO2, CH4 + C2H4, and CH4 + C3H8 hydrates in pure water were measured at four fixed temperatures of 273.4, 275.4, 277.4, and 279.4 K by means of suspending a single gas bubble in water. The results showed that the lateral growth rates of mixed-gas CH4 + C2H4 hydrate films were slower than that of pure gas (CH4 or C2H4) for the same driving force and that of mixed-gas CH4 + C3H8 hydrate film growth was the slowest. The dependence of the thickness of hydrate film on the driving force was investigated, and it was demonstrated that the thickness of hydrate film was inversely proportional to the driving force. It was found that the convective heat transfer control model reported in the literature could be used to formulate the lateral film growth rate v(f) with the driving force DeltaT perfectly for all systems after introduction of the assumption that the thickness of hydrate films is inversely proportional to the driving force DeltaT; i.e., v(f) = psiDeltaT(5/2) is correct and independent of the composition of gas and the type of hydrate. The thicknesses of different gas hydrate films were estimated, and it is demonstrated that the thicknesses of mixed-gas hydrate films were thicker than those of pure gases, which was qualitatively consistent with the experimental result.

Electrophysiological and pathological observations on experimental coxsackie B-3 viral myocarditis in mice.

Electrophysiological action of right ventricular myocardium examined by standard intracellular microelectrode technique and real-time microcomputer data processor system and histological and ultrastructural changes of myocardium in BALB/c mice infected with coxsackie B-3 virus from 3 days to 9 months were observed. It was found that electrophysiologic parameters of action potential changed very quickly at the early stage (3 days to 1 month) of the disease. Those abnormalities became most apparent by the 5-30th day, and 7 patterns of abnormal action potential occurred frequently within the same period. These changes were basically parallel to the myocardial lesions. At the late stage (3-9 months) the electrophysiological parameters were nearly normal, while the myocardial lesions decreased gradually. However, the abnormal patterns of action potential were still detected, even though they were improved gradually. The results suggest that myocardial damages caused by viral infection may lead to changes of cardiac electric action, which may be one of the factors in arrhythmias in the episode of viral myocarditis.