Molecular characteristics of the MHC-DRA genes from yak (Bos grunniens) and Chinese yakow (Bos grunniens × Bos taurus)

Two full-length cDNAs (762 bp) of the DRA gene from yak and Chinese yakow were isolated and analysed to identify structural and functional variations. The sequences for DRA in yak (Bogr-DRA) and Chinese yakow (Bogr × BoLA-DRA) were essentially identical to those for cattle (99%) and buffalo (97%). Except for two substitutions in the amino acids comprising the domain for signal peptide (SP) in yak, the additional residues were highly conserved across the species investigated. Peptide-binding site (PBS) of Bogr-DRA and Bogr × BoLA-DRA was highly reserved in the α1 domain among all species investigated. The lack of mutation in Bogr-DRA is consistent with the conception that the gene is highly conserved among all mammalian species. The very high conservation of the DRA gene among ruminants, including yak, may be due to its recent evolutionary detachment.

Standardization and cross validation of alloreactive IFNγ ELISPOT assays within the clinical trials in organ transplantation consortium

Emerging evidence indicates memory donor-reactive T cells are detrimental to transplant outcome and that quantifying the frequency of IFNγ-producing, donor-reactive PBMCs by ELISPOT has potential utility as an immune monitoring tool. Nonetheless, differences in assay performance among laboratories limit the ability to compare results. In an effort to standardize assays, we prepared a panel of common cellular reagent standards, developed and cross validated a standard operating procedure (SOP) for alloreactive IFNγ ELISPOT assays in several research laboratories supported by the NIH-funded Clinical Trials in Organ Transplantation (CTOT) Consortium. We demonstrate that strict adherence to the SOP and centralized data analysis results in high reproducibility with a coefficient of variance (CV) of ≈ 30%. This standardization of IFNγ ELISPOT assay will facilitate interpretation of data from multicenter transplantation research studies and provide the foundation for developing clinical laboratory testing strategies to guide therapeutic decision-making in transplant patients.

A method for detecting forward scattering signals on-chip with a photonic-microfluidic integrated device

A photonic integrated microfluidic device is demonstrated to perform optical excitation and forward scatter collection all on-chip in a planar format. Integrated on-chip optics formed a tailored beam geometry for optimal excitation of particles while a special design modification allowed for on-chip forward collection with the beam shaping capabilities. A notch was placed in the lens system that caused a dark spot on the facet of a collection waveguide while not affecting the beam geometry at the point of interrogation. The modified device with the ability to form a 10 μm beam geometry was demonstrated to detect the forward scatter from blank 5 μm diameter polystyrene beads. Free-space collection of side scatter signals was performed simultaneously with the on-chip collection and the designs demonstrated and enhanced SNR while the reliability of detection was determined to be appropriate for many applications. Excellent performance was confirmed via a false positive rate of 0.4%, a missed events rate of 6.8%, and a coincident rate of 96.3% as determined between simultaneously performed free-space and on-chip detection schemes.

Molecular epidemiological survey of hemoglobinopathies in the Wuxi region of Jiangsu Province, eastern China

In order to determine the prevalence and molecular characterization of hemoglobinopathies in the Wuxi region of Jiangsu Province in the People's Republic of China (PRC), a total of 10,297 healthy people selected from a regional hospital were screened. Hemoglobin (Hb) electrophoresis, complete blood cell (CBC) count, polymerase chain reaction (PCR), DNA sequencing, reverse dot-blot and multiplex ligation-dependent probe amplification (MLPA) were used to detect Hb variants, thalassemias and hereditary persistence of fetal Hb (HPFH). Two thousand and twenty-one adult subjects were screened for thalassemia, five cases were identified as α-thalassemia (α-thal) carriers including three cases of the -α(3.7) (rightward) deletion, one case of the - -(SEA) deletion and one case of β-thal [IVS-II-654 (C>T), (HBB: c.316-197C>T)]. The incidence of Hb variants, thalassemia and HPFH/δβ-thal were 0.136% (14/10,297), 0.25% (5/2021) and 0.0001% (1/10,297), respectively. Eight genotypes of Hb variants were found, including Hb E [β26(B8)Glu→Lys, GAG>AAG; HBB: c.79G>A], Hb J-Bangkok [β56(D7)Gly→Asp (GGC>GAC); HBB; c.170G>A], Hb G-Coushatta [β22(4)Glu→Ala (GAA>GCA); HBB: c.68A>C], Hb Queens [α34(B15)Leu→Arg (CTG>CGG) (α2 or α1); HBA2: c.104T>G (or HBA1)], Hb I [α16(A14)Lys→Glu, AAG>GAG (α1); HBA1: c.49A>G], Hb Beijing [α16(A14)Lys→Asn (AAG>AAC or AAT) (α2 or α1); HBA2: c.51G>C (or HBA1) or 51G>T (or HBA1)], Hb Ube-2 [α68(E17)Asn→Asp (AAC>GAC) (α2 or α1); HBA2: c.205A>G (or HBA1)] and Hb G-Taipei [β22(B4)Glu→Gly (GAA>GGA); HBB: c.68A>G]. A Sicilian δβ(0)-thal, identified for the first time in Asia, was also found in this survey.

Kidney transplantation from donors after brain or cardiac death in China--a clinical analysis of 94 cases

BACKGROUND

We analyzed outcomes of kidney transplantation (KTx) from donation after brain death (DBD) or cardiac death (DCD) in China under the current level of the health care system.

METHODS

Among 94 KTx performed from February 2007 to March 2012 in two organ transplant centers in the south of China, 50 KTx were used DBD and 44 DCD donors. We retrospectively analyzed the clinical outcomes.

RESULTS

At a mean follow-up of 25.5 months, the 1-year and 2-year graft survival rates were 96.8% and 95.2% respectively. Delayed graft function (DGF) occurred in 27.7% recipients, three of whom lost graft function. Among six observed acute rejection episodes, five were reversed. When compared to the DCD group in DBD patients were apt to recover from DGF. Serum creatinine decreased more promptly in the DBD than in DCD group. Serum creatinine in the DCD group increased after months 12, when it was significantly higher than that in the DBD group (P < .05).

CONCLUSIONS

Kidney transplantation from DBD donors showed good outcomes with few complications. Although KTx from DCD donors showed a higher DGF rate and longer duration of graft recovery, we achieved favorable short-term clinical outcome using this source.

Advances in the understanding of nanomaterial–biomembrane interactions and their mathematical and numerical modeling

The widespread application of nanomaterials (NMs), which has accompanied advances in nanotechnology, has increased their chances of entering an organism, for example, via the respiratory system, skin absorption or intravenous injection. Although accumulating experimental evidence has indicated the important role of NM–biomembrane interaction in these processes, the underlying mechanisms remain unclear. Computational techniques, as an alternative to experimental efforts, are effective tools to simulate complicated biological behaviors. Computer simulations can investigate NM–biomembrane interactions at the nanoscale, providing fundamental insights into dynamic processes that are challenging to experimental observation. This paper reviews the current understanding of NM–biomembrane interactions, and existing mathematical and numerical modeling methods. We highlight the advantages and limitations of each method, and also discuss the future perspectives in this field. Better understanding of NM–biomembrane interactions can benefit various fields, including nanomedicine and diagnosis.

[Study on biological characteristics of Cordyceps ramosa mycelia]

OBJECTIVE

To study the biological characteristics of Cordyceps ramosa mycelia.

METHODS

The effects of temperature, pH, carbon source, nitrogen source and C/N ratio on the mycelial growth of Cordyceps ramosa were investigated.

RESULTS

The optimum temperature, pH, carbon source, nitrogen source and C/N ratio for the mycelial growth were 25 degrees C, 5.0-7.0, soluble starch, yeast extract and 24:1, respectively.

CONCLUSION

The results provide a reference for cultivation of Cordyceps ramosa.

SecA2 is not required for secretion of the surface autolysin IspC in Listeria monocytogenes serotype 4b

Listeria monocytogenes is one of several Gram-positive bacteria known to contain an auxiliary ATPase (SecA2) involved in the Sec secretion of a subset of proteins important to bacterial pathogenesis, including autolysins. It is not known if IspC, a novel surface-associated autolysin essential for full virulence of L. monocytogenes serotype 4b, is SecA2-dependent for secretion. By creating a secA2 gene deletion (ΔsecA2) mutant from the wild type (WT) L. monocytogenes serotype 4b strain, in combination with the proteomic analysis of surface proteins and those secreted into the medium from both the mutant and the WT, we confirmed previous findings that two autolysins (p60 and NamA) are SecA2-dependent for secretion. However, this approach did not identify IspC as one of the surface proteins affected by the SecA2 deletion. Further experiments with immunofluorescence microscopy and Western blotting indicated that IspC was well displayed on the surface of both the ΔsecA2 mutant and WT cells, while p60 was not, clearly indicating that the secretion of IspC is not attributed to the SecA2 pathway. This finding sets IspC apart from other autolysins involved in virulence, such as p60 and NamA, in that SecA2 is not required for IspC secretion.

Effects of nerve growth factor on the action potential duration and repolarizing currents in a rabbit model of myocardial infarction

OBJECTIVES

To investigate the effect of nerve growth factor (NGF) on the action potential and potassium currents of non-infarcted myocardium in the myocardial infarcted rabbit model.

METHODS

Rabbits with occlusion of the left anterior descending coronary artery were prepared and allowed to recover for eight weeks (healed myocardial infarction, HMI). During ligation surgery of the left coronary artery, a polyethylene tube was placed near the left stellate ganglion in the subcutis of the neck for the purpose of administering NGF 400 U/d for eight weeks (HMI + NGF group). Cardiomyocytes were isolated from regions of the non-infarcted left ventricular wall and the action potentials and ion currents in these cells were recorded using whole-cell patch clamps.

RESULTS

Compared with HMI and control cardiomyocytes, significant prolongation of APD50 or APD90 (Action potential duration (APD) measured at 50% and 90% of repolarization) in HMI + NGF cardiomyocytes was found. The results showed that the 4-aminopyridine sensitive transient outward potassium current (I to), the rapidly activated omponent of delayed rectifier potassium current (I Kr), the slowly activated component of delayed rectifier potassium current (I Ks), and the L-type calcium current (I CaL) were significantly altered in NGF + HMI cardiomyocytes compared with HMI and control cells.

CONCLUSIONS

Our results suggest that NGF treatment significantly prolongs APD in HMI cardiomyocytes and that a decrease in outward potassium currents and an increase of inward Ca(2+) current are likely the underlying mechanism of action.

Knocking down SMC1A inhibits growth and leads to G2/M arrest in human glioma cells

Cohesin, a multiunit complex of SMC1A, SMC3 and Rad21, associates with chromatin after mitosis and holds sister chromatids together following DNA replication. It has been reported that SMC1A is mutated in some cancer types, leading to genomic instability and abnormal cell growth. In this study, we investigated the role of SMC1A in human glioma. We found that SMC1A was expressed at abnormally high levels in human glioma tissue and in cultured U251 glioma cells. Knocking down SMC1A expression in U251 cells with SMC1A-targeted interfering RNAs inhibited cell growth and induced G2/M cell cycle arrest. Furthermore, expression of the cell cycle associated gene CCNB1IP1 was dramatically increased, whereas expression of Cyclin B1 was decreased in SMC1A-deficienct U251 cells. These results suggest that SMC1A upregulation is involved in the pathogenesis of glioma.

Rational reprogramming of fungal polyketide first-ring cyclization

Resorcylic acid lactones and dihydroxyphenylacetic acid lactones represent important pharmacophores with heat shock response and immune system modulatory activities. The biosynthesis of these fungal polyketides involves a pair of collaborating iterative polyketide synthases (iPKSs): a highly reducing iPKS with product that is further elaborated by a nonreducing iPKS (nrPKS) to yield a 1,3-benzenediol moiety bridged by a macrolactone. Biosynthesis of unreduced polyketides requires the sequestration and programmed cyclization of highly reactive poly-β-ketoacyl intermediates to channel these uncommitted, pluripotent substrates to defined subsets of the polyketide structural space. Catalyzed by product template (PT) domains of the fungal nrPKSs and discrete aromatase/cyclase enzymes in bacteria, regiospecific first-ring aldol cyclizations result in characteristically different polyketide folding modes. However, a few fungal polyketides, including the dihydroxyphenylacetic acid lactone dehydrocurvularin, derive from a folding event that is analogous to the bacterial folding mode. The structural basis of such a drastic difference in the way a PT domain acts has not been investigated until now. We report here that the fungal vs. bacterial folding mode difference is portable on creating hybrid enzymes, and we structurally characterize the resulting unnatural products. Using structure-guided active site engineering, we unravel structural contributions to regiospecific aldol condensations and show that reshaping the cyclization chamber of a PT domain by only three selected point mutations is sufficient to reprogram the dehydrocurvularin nrPKS to produce polyketides with a fungal fold. Such rational control of first-ring cyclizations will facilitate efforts to the engineered biosynthesis of novel chemical diversity from natural unreduced polyketides.