Intraspecific Diversity and Taxonomy of Emmonsia crescens

Mycopathologia - Emmonsia crescens is known as an environmental pathogen causing adiaspiromycosis in small rodents. As the generic name Emmonsia is no longer available for this species, its...     

A novel immunoproteomics method for identifying in vivo-induced Campylobacter jejuni antigens using pre-adsorbed sera from infected patients

Background

Campylobacter jejuni is an important food-borne and zoonotic pathogen with a worldwide distribution. Humans and chickens are hosts of this pathogen. At present, there is no ideal vaccine for controlling human campylobacteriosis or the carriage of C. jejuni by chickens. Bacterial in vivo-induced antigens are useful as potential vaccine candidates and biomarkers of virulence.

Methods

In this study, we developed a novel systematic immunoproteomics approach to identify in vivo-induced antigens among the total cell proteins of C. jejuni using pre-adsorbed sera from patients infected with C. jejuni.

Results

Overall, 14 immunoreactive spots were probed on a PVDF membrane using pre-adsorbed human sera against C. jejuni. Then, we excised these protein spots from a duplicate gel and identified using MALDI–TOF MS. In total, 14 in vivo-induced antigens were identified using PMF and BLAST analysis. The identified proteins include CadF (CadF-1 and CadF-2), CheW, TufB, DnaK, MetK, LpxB, HslU, DmsA, PorA, ProS, CJBH_0976, CSU_0396 and hypothetical protein cje135_05017. Real-time RT-PCR was performed on 9 genes to compare their expression levels in vivo and in vitro. The data showed that 8 of the 9 analyzed genes were significantly upregulated in vivo relative to in vitro.

Conclusion

We successfully developed a novel immunoproteomics method for identifying in vivo-induced Campylobacter jejuni antigens by using pre-adsorbed sera from infected patients.

General significance

This new analysis method may prove to be useful for identifying in vivo-induced antigens within any host infected by bacteria and will contribute to the development of new subunit vaccines.     

Abundance and Diversity of Ammonia-Oxidizing Bacteria and Archaea in Cold Springs on the Qinghai-Tibet Plateau

The cold springs underlain by gas hydrates on the Qinghai-Tibet Plateau (QTP) are similar to deep-sea cold seeps with respect to methane biogeochemistry. Previous studies have shown that ammonia oxidizing bacteria (AOB) and archaea (AOA) are actively present and play important roles in the carbon/nitrogen cycles in cold seeps. Studying AOA and AOB communities in the QTP cold springs will be of great importance to our understanding of carbon and nitrogen cycling dynamics related to the underlying gas hydrates on the QTP. Thus, the abundance and diversity of AOB and AOA in sediments of four cold springs underlain by gas hydrates on the QTP were determined by using quantitative polymerase chain reaction and amoA gene (encoding ammonia monooxygenase involved in ammonia oxidation) phylogenetic analysis. The results showed that the AOB and AOA amoA gene abundances were at 10³–10⁴ copies per gram of the sediments in the investigated cold springs. The AOB population consisted of Nitrosospira and Nitrosomonas in contrast with the mere presence of Nitrosospira in marine cold seeps. The AOB diversity was higher in cold springs than in cold seeps. The AOA population was mainly composed of Nitrososphaera, in contrast with the dominance of Nitrosopumilus in cold seeps. The terrestrial origin and high level of dissolved oxygen of the cold springs may be the main factors accounting for the observed differences in AOB and AOA populations between the QTP cold springs and marine cold seeps.     

S‐nitrosylated protein disulfide isomerase contributes to mutant SOD1 aggregates in amyotrophic lateral sclerosis

A major hallmark of mutant superoxide dismutase (SOD1)‐linked familial amyotrophic lateral sclerosis is SOD1‐immunopositive inclusions found within motor neurons. The mechanism by which SOD1 becomes aggregated, however, remains unclear. In this study, we aimed to investigate the role of nitrosative stress and S‐nitrosylation of protein disulfide isomerase (PDI) in the formation of SOD1 aggregates. Our data show that with disease progression inducible nitric oxide synthase (iNOS) was up‐regulated, which generated high levels of nitric oxide (NO) and subsequently induced S‐nitrosylation of PDI in the spinal cord of mutant SOD1 transgenic mice. This was further confirmed by in vitro observation that treating SH‐SY5Y cells with NO donor S‐nitrosocysteine triggered a dose‐dependent formation of S‐nitrosylated PDI. When mutant SOD1 was over‐expressed in SH‐SY5Y cells, the iNOS expression was up‐regulated, and NO generation was consequently increased. Furthermore, both S‐nitrosylation of PDI and the formation of mutant SOD1 aggregates were detected in the cells expressing mutant SOD1^G93A. Blocking NO generation with the NOS inhibitor N‐nitro‐l ‐arginine attenuated the S‐nitrosylation of PDI and inhibited the formation of mutant SOD1 aggregates. We conclude that NO‐mediated S‐nitrosylation of PDI is a contributing factor to the accumulation of mutant SOD1 aggregates in amyotrophic lateral sclerosis.     

Seed rain and its relationship with above-ground vegetation of degraded Kobresia meadows

Seed rain is a crucial element in vegetation regeneration, but has been rarely studied in high altitude regions, particularly degraded Kobresia meadow. Weed infestation is a distinctive feature of pasture degradation in Kobresia meadows on the Tibetan plateau, the ecological mechanism of which is closely related with vegetation’s seed rain. In this paper we assess the effect of vegetation degradation on seed rain and consider its implication for restoration of degraded Kobresia meadows in the headwater area of Yellow river, through analysis of seed species composition, number of seeds landing per m² of soil surface, and their relationship with above ground vegetation. Vegetation degradation had an impact on the species composition and numbers of seeds in seed rain and their relationship with above-ground vegetation. Within the un-degraded meadow, which provided a closed vegetation cover, 35 % of the seed rain was of sedge and gramineae species. However, within the degraded meadows, as the extent of degradation increased, so the total number of seeds m^?2 increased, with those derived from sedge and gramineae species forming a declining proportion of the total. Degradation of Kobresia meadow on the Tibetan plateau is exacerbated by the seed input of weed species (such as Oxytropis ochrocephala, Carum carvi, Aconitum pendulum, Pedicularis kansuensis in this study). Therefore, a major priority for the restoration of such degraded meadows should be the elimination of these weeds from the above ground vegetation by human intervention.     

3,5-Diiodo-l-thyronine ameliorates diabetic nephropathy in streptozotocin-induced diabetic rats

3, 5-Diiodothyronine (T2), a natural metabolite of triiodothyronine (T3) from deiodination pathway, can mimic biologic effects of T3 without inducing thyrotoxic effects. Recent studies revealed T3 acted as a protective factor against diabetic nephropathy (DN). Nevertheless, little is known about the effect of T2 on DN. This study was designed to investigate whether and how T2 affects experimental models of DN in vivo and in vitro. Administration of T2 was found to prevent significant decrease in SIRT1 protein expression and activity as well as increases in blood glucose, urine albumin excretion, matrix expansion, transforming growth factor-β1 expression, fibronectin and type IV collagen deposition in the diabetic kidney. Concordantly, similar effects of T2 were exhibited in the cultured rat mesangial cells (RMC) exposed to high glucose and that could be abolished by a known SIRT1 inhibitor, sirtinol. Moreover, enhanced NF-κB acetylation and JNK phosphorylation present in both diabetic rats and high glucose-treated RMC were distinctly dampened by T2. Collectively, these results suggested that T2 was a protective agent against renal damage in diabetic nephropathy, whose action involved regulation of SIRT1.     

Three‐dimensional neural differentiation of embryonic stem cells with ACM induction in microfibrous matrices in bioreactors

The clinical use of pluripotent stem cell (PSC)‐derived neural cells requires an efficient differentiation process for mass production in a bioreactor. Toward this goal, neural differentiation of murine embryonic stem cells (ESCs) in three‐dimensional (3D) polyethylene terephthalate microfibrous matrices was investigated in this study. To streamline the process and provide a platform for process integration, the neural differentiation of ESCs was induced with astrocyte‐conditioned medium without the formation of embryoid bodies, starting from undifferentiated ESC aggregates expanded in a suspension bioreactor. The 3D neural differentiation was able to generate a complex neural network in the matrices. When compared to 2D differentiation, 3D differentiation in microfibrous matrices resulted in a higher percentage of nestin‐positive cells (68% vs. 54%) and upregulated gene expressions of nestin, Nurr1, and tyrosine hydroxylase. High purity of neural differentiation in 3D microfibrous matrix was also demonstrated in a spinner bioreactor with 74% nestin + cells. This study demonstrated the feasibility of a scalable process based on 3D differentiation in microfibrous matrices for the production of ESC‐derived neural cells. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1013–1022, 2013