Structure and Function of SLC4 Family [Formula: see text] Transporters

The solute carrier SLC4 family consists of 10 members, nine of which are [Formula: see text] transporters, including three Na(+)-independent Cl(-)/[Formula: see text] exchangers AE1, AE2, and AE3, five Na(+)-coupled [Formula: see text] transporters NBCe1, NBCe2, NBCn1, NBCn2, and NDCBE, as well as "AE4" whose Na(+)-dependence remains controversial. The SLC4 [Formula: see text] transporters play critical roles in pH regulation and transepithelial movement of electrolytes with a broad range of demonstrated physiological relevances. Dysfunctions of these transporters are associated with a series of human diseases. During the past decades, tremendous amount of effort has been undertaken to investigate the topological organization of the SLC4 transporters in the plasma membrane. Based upon the proposed topology models, mutational and functional studies have identified important structural elements likely involved in the ion translocation by the SLC4 transporters. In the present article, we review the advances during the past decades in understanding the structure and function of the SLC4 transporters.

Genetic analysis revealed LX4 genotype strains of avian infectious bronchitis virus became predominant in recent years in Sichuan area, China

Between 2008 and 2010, 19 strains of infectious bronchitis virus (IBV) were isolated from the vaccinated chicken flocks in Sichuan province, China. The S1 genes of the isolates were amplified and sequenced. Phylogenetic analysis revealed that the 19 isolates and 37 reference IBV strains can be grouped into eight genotypes. Although IBVs of Taiwan-I type, massachusetts type, and proventriculitis type were isolated, but most isolates were LX4 genotype. Homology analysis of the sequences of S1 genes of the 19 isolates and 37 reference IBV strains revealed that the identity of the nucleotides and amino acid sequences of the S1 genes between the 15 LX4-type isolates and other IBV strains were 71.9–99.3% and 72.1–99.1%, respectively, while those of the analyzed IBV of LX4 type were 96.0–99.9% and 94.3–99.8%, respectively. The results from this study and other published results in the GenBank database showed that isolates circulating in Sichuan province in recent years were mainly LX4 genotype, which is the predominant genotype circulated in China in recent years.

A monoclonal antibody blocking ELISA to detect serotype-specific infectious bronchitis virus antibodies

A monoclonal antibody (Mab) blocking enzyme-linked immunosorbent assay (B-ELISA) was developed and compared to a conventional indirect ELISA (I-ELISA) and a virus-neutralization (VN) test for detection of specific antibodies to avian infectious bronchitis virus (IBV) serotypes. Sera used in this study were derived from chickens experimentally inoculated with the three most prevalent IBV serotypes, Arkansas (Ark), Connecticut (Conn), and Massachusetts (Mass). Overall, there was good correlation between the results of B-ELISA and the VN test. Both detected serotype-specific antibodies in chicken sera during primary and secondary phases of the immune response. Results of both tests indicated that the antibodies produced during the primary response to IBV serotypes are strongly serotype-specific. Those produced during the secondary response react more strongly with the homologous virus, but do exhibit some level of cross-reactivity with heterologous antigens. I-ELISA detected IBV group-specific and not serotype-specific antibodies. The B-ELISA which both offers the convenience of the conventional I-ELISA and the serotype specificity of the VN test, hold excellent promise for field application in IBV diagnosis and evaluation of response to IBV vaccines.