Science in China Series C: Life Sciences

Hydrocalumite, a calcium aluminate hydrate phase, consists of positively-charged structure units, and is therefore an ideal candidate for accommodating anionic contaminants. In this study, a series of batch experiments was carried out to examine the uptake of chromate and selenate by hydrocalumite. To determine the uptake capacity and long-term stability, hydrocalumite solid solutions between chromate/selenate and hydroxyl were synthesized over a reaction time of more than one year. At a ratio of water to initial solids added (CaAI2O4+CaO) of 75:1, the maximum uptake capacities were over 77 and 114 g/kg for Cr and Se, respectively. These values are very close to the theoretical uptake capacities of chromate and selenate hydrocalumite end members (81 and 118 g/kg, respectively). The oxyanion removal efficiency from solution was above 95%. Due to the high uptake capacity and anion removal efficiency of hydrocalumites, their application in wastewater treatment is promising. Hydrocalumites are also important hydration products of cementitious materials, the long-term stability of these phases is of significance for application in solidification/stabilization technology.

The antisense fragments, which were available inin vitro system, were cloned into the mammalian expression vector pcDNA3, and were transfected into H654 cells, a mammalian cell line stably expressing the thalassaemic (IVS-2-654 C→T) human β-globin gene. In these transfected cells, the level of correctly spliced β-globin mRNA in total β-globin mRNA (β/(β + β*)) was improved from 0.07 (0 d) to 0.22 (3 d), and this effect persisted for up to 15 d post transfection. All the results demonstrated that antisense RNAs were able to be transcribed from the antisense fragment expression vectors stably and effectively suppressed aberrant splicing pattern of the mutated β-globin gene (IVS-2-654 C→T) and restored correct splicing pathway. This work provided a novel approach with potential clinical significance to gene therapy of this kind of splicing mutants including β-thalassaemia (IVS-2-654 C→T) by antisense RNAs.

Betaine as one of osmolytes plays an important role in osmoregulation of most high plants. Betaine aldehyde dehydrogenase (BADH) is the second enzyme involved in betaine biosynthesis. The BADH gene from a halophite,Atriplex hortensis, was transformed into rice cultivars by bombarment method. Totally 192 transgenic rice plants were obtained and most of them had higher salt tolerance than controls. Among transgenic plants transplanted in the saline pool containing 0.5% NaCl in a greenhouse, 22 survived. 13 of which set seeds, and the frequency of seed setting was very low, only 10%. But the controls could not grow under the same condition. The results of BADH activity assay and Northern blot showed that the BADH gene was integrated into chromosomes of transgenic plants and expressed.

The availability of the draft genome sequence of Oryza sativa L. ssp. indica has made it possible to study the rice tRNA genes. A total of 596 tRNA genes, including 3 selenocysteine tRNA genes and one suppressor tRNA gene are identified in 127551 rice contigs. There are 45 species of tRNA genes and the revised wobble hypothesis proposed by Guthrie and Abelson is perfectly obeyed. The relationship between codon usage and the number of corresponding tRNA genes is discussed. Redundancy may exist in the present list of tRNA genes and novel ones may be found in the future. A set of 33 tRNA genes is discovered in the complete chloroplast genome of Oryza sativa L. ssp. indica. These tRNA genes are identical to those in ssp. japonica identified by us independently from the origional annotation.

The pharmacodynamics of Annexin32, a new Ca2+-dependent phospholipid-binding protein, was studied by measuring coagulation time in rabbits and venous thrombosis in rabbits and rats. Rabbits and rats were given Annexin32 by intravenous administration. Then Kaolin partial thromboplastin time (KPTT), thrombosis in vitro and in vivo were assayed. The results showed that KPTT of rabbits was prolonged (p < 0.01), and the length and weight of thrombus in vitro were reduced (p < 0.01) after administration of Annexin32 at 1 mg/kg. It also inhibited thrombosis in vivo and reduced the weight of venous thrombus significantly in rats (p < 0.01). All these results suggested that Annexin32 possesses the characteristic of antithrombotic effect and fewer side effects on coagulation time.

Using the method of gene transfection with liposome, we obtained the mouse erythroleukemia cell line MEL-TF19, which stably carries TFAR19, a novel apoptosis-related gene. The expression of TFAR19 was detected by Western blot. Growth curve and flow cytometry analysis showed that after being transfected with TFAR19 gene, the growth of MEL-TF19 is suppressed and its apoptosis is accelerated because of the serum deprivation. Our biorheological study indicated that in the apoptotic process, compared with MEL cells, MEL-TF19 cells exhibit larger osmotic fragility, lower cell surface charge density, increased elastic modulus K 1 which is inversely proportional to cells’ maximal deformation ability, obviously diminished surface viscosity μ, with elastic modulus K 2having no distinct changes. The above results provided some bases for recognizing the function of TFAR19 completely from the viewpoint of biorheology.

In the present study, a new member of melanoma associated antigens (Mage), named Restin (219 amino acids), was identified from HL-60 cell induced by all-trans-retinoic acid (ATRA) by PCR-based subtractive hybridization. Bioinformatics analysis found this novel gene shares high homolog with Necdin (a neuronal growth suppressor, 49%). Both of them are basic proteins. Moreover, the Restin, Necdin and Mages are in one protein superfamily. This fact indicates that the Restin and Mages are mutually related but functionally different. Further analysis found that they can be divided into two subgroups, the acid and the basic. Restin, Necdin and Mage-D1 have an alkaline conserve region (PI is from 8.6 to 10.1), which are not or less expressed in tumor tissues but mostly in normal tissues. It has been reported that Necdin can arrest the cell proliferation by interaction with p53 and E2F1. Therefore, all of them are probably related to arrest the cell cycle. However, the Mage A and C are primarily acid proteins (PI is from 4.2 to 4.9), not expressed in normal tissues but in tumors. It is quite probable that these proteins are involved in the cell proliferation. We therefore suggest that these two protein families might be a pair of control elements of cell cycle—“in cycle or out of cycle”.

Human mutant-type (mt) p53 cDNA was synthesized and cloned from human lung cancer cell line GL containing mt-p53 gene by using polymerase chain reaction (PCR). It was confirmed that the mt-p53 cDNA contained the complete coding sequence of p53 gene but mutated at codon 245 (G→T) and resulted in glycine to cysteine by sequencing analysis. The retroviral vector pD53M of the mt-p53 was constructed and introduced into the drug-sensitive human lung cancer cells GAO in which p53 gene did not mutate. The transfected GAO cells strongly expressed mutant-type p53 protein by immunohistochemistry, showing that pD53M vector could steadily express in GAO cells. The drug resistance to several anticancer agents of GAO cells infected by pD53M increased in varying degrees, with the highest increase of 4-fold,in vitro andin vivo. By quantitative PCR and flow cytometry (FCM) analyses, the expression of MDR1 gene and the activity of P-glycoprotein (Pgp) did not increase, the expression of MRP gene and the activity of multidrug resistance-related protein (Mrp) increased slightly. These results indicated that the drug resistance associated with mt-p53 gene might be somewhat correlated with MRP/Mrp but not with MDR1/Pgp. It was possible to modify the tumor drug resistance by changing status of p53 gene.

The 3′ leader and the 5′ trailer of the rice yellow stunt rhabdovirus (RYSV) genomic RNA have been cloned and sequenced. Sequence data indicate that the RYSV leader region is composed of 203 nucleotides (nt) and the trailer region 191 nt. The terminal 9 nt of the two regions are complementary and capable of forming a putative panhandle structure common to rhabdovirus genomes. In comparison with the leader or trailer sequences of other rhabdoviruses reported so far, both the leader and trailer of RYSV are the longest and there is no obvious sequence homology between the counterparts except for a few terminal nt and the UGUU motif in the leader sequences. Polyadenylated plus-strand leader RNA has been detected in RYSV-infected rice plants by 3′ RACE. This is the second example in rhabdoviruses following the report for sonchus yellow net virus (SYNV) for existence of a polyadenylated leader RNA. No polyadenylated plus-strand transcripts of the RYSV trailer have been found using the similar method.