Eukaryotic elongation factor 1 alpha (eEF1A) delivers aminoacyl-tRNA to the ribosome and thereby plays a key role in protein synthesis. Human eEF1A is subject to extensive post-translational methylation, but several of the responsible enzymes remain unknown. Using a wide range of experimental approaches, we here show that human methyltransferase (MTase)-like protein 13 (METTL13) contains two distinct MTase domains targeting the N terminus and Lys55 of eEF1A, respectively. Our biochemical and structural analyses provide detailed mechanistic insights into recognition of the eEF1A N terminus by METTL13. Moreover, through ribosome profiling, we demonstrate that loss of METTL13 function alters translation dynamics and results in changed translation rates of specific codons. In summary, we here unravel the function of a human MTase, showing that it methylates eEF1A and modulates mRNA translation in a codon-specific manner.

The high rate of drop out is still a problem in the distance learning system, including at the Universitas Terbuka (UT). At UT, the term dropout is better known as the status of non-active students. The study aims was to determine the median time and determinant of non-active student in distance learning in Indonesia. This study used a cohort analysis in student of biology department who first registered in 2012 to 2014. The median time of non-active students was identified by the Kaplan-Meier analysis and the determinant of non-active student was analyzed by Cox proportional hazard model. The percentage of non-active students in this study reached 42%, with half of the students becoming non-active in the first two semesters. Students who have a greater risk of becoming non-active are those who are >45 years old, women, employed, recent education is not relevant to the field of biology, knowledge of the concept of distance learning and laboratory practice is lacking, has never participated in online tutorials and face-to-face tutorials, and is not satisfied existing academic services. The optimization of the provision and quality of preferred learning services at the beginning of the semester will be able to avoid higher-risk of non-active students.

MDCK and Vero cell lines have been used as substrates for influenza virus replication. However, Vero cells produced lower influenza virus titer yield compared to MDCK. Influenza virus needs molecules for internalisation of the virus into the host cell, such as influenza virus receptor and clathrin. Human influenza receptor is usually a membrane protein containing Sia(α2,6) Gal, which is added into the protein in the golgi apparatus by α2,6 sialyltransferase (SIAT1). Light clathrin A (LCA), light clathrin B (LCB) and heavy clathrin (HC) are the main components needed for virus endocytosis. Therefore, it is necessary to compare the expression of SIAT1 and clathrin in Vero and MDCK cells. This study is reporting the expression of SIAT1 and clathrin observed in both cells with respect to the levels of (1) RNA by using RT-PCR, (2) protein by using dot blot analysis and confocal microscope. The results showed that Vero and MDCK cells expressed both SIAT1 and clathrin proteins, and the expression of SIAT1 in MDCK was higher compared to Vero cells. On the other hand, the expressions of LCA, LCB and HC protein in MDCK cells were not significantly different to Vero cells. This result showed that the inability of Vero cells to internalize H1N1 influenza virus was possibly due to the lack of transmembrane protein receptor which contained Sia(α2,6) Gal.

Trypsin is supposed to the influenza virus into host purpose of this study is to determine the role of trypsin process of the influenza H1N1 virus in Vero and MDCK (M Kidney) cells; to see whether trypsin receptor-mediated endocytosis or non viruses were inoculated into Vero and MDCK cells under three conditions: (1) without trypsin in the medium trypsin (VTVi1 and MTVi1) inoculation and incubated with medium containing trypsin (VTVi2 and MTVi2). Advance cytopathic effect HA (hemagglutination) titer cells. Moreover, HA titer on MTVi1 was higher than MVi, and the lowest was found on MTVi2. Trypsin supported the internali the cleavage of HA glycoprotein halt the internalization of with trypsin before virus inoculation. Trypsin could digest protein containing sialic aci Conversely, trypsin did not Vero cells based on HA titer. This result was also supported by TEM observation, which showed that influenza virus is very low. We sugges 2,6)-containing receptor on the membrane of virus internalization. On the other hand, active internalization of the virus was seen in all groups of MDCK cells (MVi, MTVi1, and MTVi2). However, trypsin could not trigger the internali cells via non-receptor-mediated endocytosis. From this study it can be concluded that trypsin enhanced the cleavage of the hemagglutinin (HA) of the virus, but did not improve the ability of the host cells to internalize the virus, especially via non endocytosis.

Abstract. Hewindati YT, Suhardi DA, Zuhairi FR, Diki, Yuliana E. 2022. Occurrence of heavy metals Cu, Pb, and Cd in Rhizophora apiculata and Sonneratia caseolaris in the coastal area of Subang, West Java, Indonesia. Biodiversitas 23: 6471-6479. The high urbanization in coastal areas is one of the causes of mangrove ecosystems experiencing pressure due to water pollution by anthropogenic activities, especially through heavy metals pollution. As vegetation grows in transitional areas, mangroves have a different structure and physiology from plants in the land area, so they have a high resistance to the pressure of heavy metal pollution. The measurement was carried out on the content of heavy metals Cadmium (Cd), Cuprum (Cu), and Plumbum (Pb) in Subang, West Java. Our study aimed to evaluate the characteristics of heavy metal found in the roots, leaves, and trunks of species Rhizophora apiculata Blume and Sonneratia caseolaris (L.) Engler. Sampling was conducted in the rivers at three locations: Langensari, Blanakan, and the estuary area. The concentration of heavy metals in each organ was measured using Atomic Absorption Spectrophotometry (AAS). The Multiple Factor Analysis (MFA) technique was used to obtain a more detailed description of the accumulation pattern of heavy metals. The mapping was carried out using a two-dimensional plot containing 18 observation samples, nine variable combinations of heavy metal content in three organs, and the location of observations and plant species. Both plant species had a high accumulation absorption of heavy metals but with different characteristics. S. caseolaris determined the accumulation characteristics of Cu and Cd in the three observation areas with a total contribution of 60.3%. Meanwhile, R. apiculata significantly contributed to determining the characteristics of the accumulation of Cu and Pb in the entire observation area, with its contribution of 15.5%. However, the highest average accumulation of Pb was found in the R. apiculata leaves in Blanakan and the estuary area, which was 16.054 mg/kg and 12.769 mg/kg, respectively.