Synergetic effect of pH and biochemical components on bacterial diversity during mesophilic anaerobic fermentation of biomass-origin waste

Aims: To investigate the synergetic effect of pH and biochemical components on bacterial community structure during mesophilic anaerobic degradation of solid wastes with different origins, and under acidic or neutral conditions. Methods and Results: The bacterial community in 16 samples of solid wastes with different biochemical compositions and origins was evaluated during mesophilic anaerobic degradation at acidic and neutral pH. Denaturing gradient gel electrophoresis (DGGE) and single‐strand conformation polymorphism (SSCP) were used to compare the communities. Multivariate analysis of the DGGE and SSCP results revealed that most of the dominant microbes were dependent on the content of easily degradable carbohydrates in the samples. Furthermore, the dominant microbes were divided into two types, those that preferred an acid environment and those that preferred a neutral environment. A shift in pH was found to change their preference for medium substrates. Although most of the substrates with similar origin and biochemical composition had similar microbial diversity during fermentation, some microbes were found only in substrates with specific origins. For example, two microbes were only found in substrate that contained lignocellulose and animal protein without starch. These microbes were related to micro‐organisms that are found in swine manure, as well as in other intestinal or oral niches. In addition, the distribution of fermentation products was less sensitive to the changes in pH and biochemical components than the microbial community. Conclusions: Bacterial diversity during anaerobic degradation of organic wastes was affected by both pH and biochemical components; however, pH exerted a greater effect. Significance and Impact of the Study: The results of this study reveal that control of pH may be an effective method to produce a stable bacterial community and relatively similar product distribution during anaerobic digestion of waste, regardless of variation in the waste feedstocks.     

Vimentin is important in the neural differentiation of PC12 cells promoted by sialylation

Sialic acid modification is a kind of post-translational modification. To investigate the regulation effect of sialic acid on neural differentiation, we used CycloManN propanyl perac (CycloManN pro), a metabolic precursor of sialic acid, to treat PC12 cells. We noted that CycloManN pro indeed robustly promoted global sialylation detected by MAL II lectin blot in PC12 cells. Simultaneously, we interestingly found that the neurite outgrowth of PC12 cells was significantly promoted by the CycloManN pro treatment. The profile analysis of sialylated proteins showed that a protein band at 55KD was greatly enhanced especially in PC12L cells after CycloManN pro treatment. After enrichment with lectin MAL II, the proteins in this band were analyzed by mass spectrometry. The results showed that 23 proteins were in the band, but the score of vimentin was the highest among them. To investigate further the role of vimentin in the process of neurite differentiation, vimentin construct was transfected into PC12 cells. We interestingly observed that ectopic expression of vimentin significantly enhanced the neurite outgrowth induced by CycloManN pro. However, after three potential glycosylation sites (Ser-7, Thr-33, Ser-34:) of vimentin were mutated to alanine, overexpression of the mutated vimentin completely lost the enhancement activity for the neural differentiation even in the presence of CycloManN pro. Taken together, our study demonstrated that vimentin was important in the induction of neural differentiation by CycloManN pro.     

Enhanced isomer purity of lactic acid from the non-sterile fermentation of kitchen wastes

In order to improve the purity of lactic acid isomers, the effects of pH, temperature, fermentation time and their interactions on l(+) or d(-)-lactic acid production were evaluated during lactic acid fermentation of the non-sterile kitchen wastes. The results showed that l(+)-lactic acid was the main isomeric form. The isomer purity was much higher at acidic or alkalic pH (non-controlled pH, pH 5 and pH 8) than neutral pH (pH 6 and pH 7). Increasing the fermentation temperature from 35 degrees C to 45 degrees C at pH 7 enhanced the isomer purity from 60:40 to 83:17. The optimal fermentation time for the purity of lactic acid isomers was found to depend on the corresponding pH and temperature. From the response surface analysis, the optimized combination of pH and temperature could obviously increase the l(+)-isomer concentration. It is confirmed that the variation of the isomer purity with pH, temperature and fermentation time change resulted from the substitution of microbial community composition. The lactic acid bacteria and Clostridium sp. dominated the fermentation of non-sterile kitchen wastes, and the emergence and disappearance of lactic acid bacteria which produced l(+)-isomer and Clostridium sp. resulted in the variations of the isomer purity.     

Monthly change of community structure of zoobenthos in Xiangxi Bay after impoundment of the Three Gorges Teservoir, China

Xiangxi Bay, a typical bay of the Three Gorges Reservoir (TGR) in China, was formed in June 2003 after the impoundment of the TGR. We investigated the community structure of zoobenthos in Xiangxi Bay from August 2003 to August 2004. Benthic abundance and biomass were calculated per unit area of sediment. A total of 26 taxa were identified. They included two families of Lamellibranchia (7.7% of the total taxa number), two families of Oligochaeta (50%), Chironomidae (38.5%), and one other animal (3.8%). The average density and biomass were 276 ind./m² and 0.301 g/m², respectively. Oligochaetes and chironomids constituted the major groups, and Limnodrilus hoffmeisteri, Procladius sp., Branchiura sowerbyi, Tubificidae sp1. and Polypedilum scalaenum group sp. were the common taxa in this reservoir system. Among them, L. hoffmeisteri and Procladius sp. were the dominant species, and contributed 37.0% and 28.3% of the total density, respectively. The standing crop of zoobenthos in Xiangxi Bay was relative low, compared with other similar reservoirs. Our studies demonstrate that the standing crop increased gradually with time. The total density and biomass in August 2004 were 8.8 and 14.3 times those of the initial impoundment, separately. Oligochaetes did not become the sole dominant group, indicating that the sediment loading in Xiangxi Bay may be not serious. __________ Translated from Acta Hydrobiologica Sinica, 2006, 30(1): 64–69 [译自: 水生生物学报]     

高压力对限制性内切酶活性的影响

以质粒ｐＳＰＯＲＴ１为底物研究了高压力对Ⅱ型限制性内切酶ＨｉｎｄⅢ和ＸｂａⅠ反应的影响。高压力未引起两酶底物碱基特异性的改变,但二者反应活力均随压力升高而逐渐下降,ＸｂａⅠ对高压力更敏感。引起ＨｉｎｄⅢ和ＸｂａⅠ限制性内切酶活性完全丧失的压力分别为２００和１８０ＭＰａ,半失活压力分别为１３０和７５ＭＰａ。     

Stimulation of ATG12-ATG5 conjugation by ribonucleic acid

The ubiquitin-like conjugation reactions, ATG8/microtubule-associated protein 1 light chain 3/MAP1LC3 (LC3) to phosphatidylethanolamine (PE) and ATG12 to ATG5, are biochemical hallmarks for autophagy, a cellular process that degrades bulk cellular proteins and organelles. The two conjugation reactions share the same E1-like enzyme ATG7 but have different E2-like enzymes, ATG3 for LC3-PE and ATG10 for ATG12-ATG5. In cells, ATG12-ATG5 conjugation appears to be required for LC3-PE conjugation. Previously, in vitro reconstitution of LC3-PE conjugation, but not the upstream ATG12-ATG5 conjugation, was reported. In this study, we describe for the first time the de novo reconstitution of mammalian ATG12-ATG5 conjugation by using purified recombinant proteins. We show that ATG7, ATG10 and ATP as an energy source are all essential for ATG12-ATG5 conjugation, and mutation of the specific lysine residue of ATG5 for ATG12 conjugation abrogates the reaction. Furthermore, a potent stimulating activity for ATG12-ATG5 conjugation was detected in mammalian cell extracts, and was surprisingly identified as ribosomes. Our detail biochemical analyses indicate that the ribonucleic acid (RNA) component of ribosomes is both necessary and sufficient for this stimulation.     

The changing incidence of human papillomavirus-associated oropharyngeal cancer using multiple imputation from 2000 to 2010 at a Comprehensive Cancer Centre

Introduction Human papillomavirus (HPV) is a risk and prognostic factor for oropharyngeal cancer (OPC). Determining whether the incidence of HPV-associated OPC is rising informs health policy. Methods HPV status was ascribed using p16 immunohistochemistry in 683/1474 OPC patients identified from the Princess Margaret Hospital's Cancer Registry (from 2000 to 2010). Missing p16 data was estimated using multiple (n = 100) imputation (MI) and validated using an independent OPC cohort (n = 214). Non-OPC head and neck squamous cell carcinoma (HNSCC) (n = 3262) were also used for time-trend comparison. Regression was used to compare HNSCC subsets and time-trends. The c-index was used to measure the predictive ability of MI. Results The incidence of OPC rose from 23.3% of all HNSCC in 2000 to 31.2% in 2010 (p = 0.002). In the subset of OPC tested for p16, there was no change in p16 positivity over time (p = 0.9). However, p16 testing became more frequent over time (p < 0.0001), but was nonetheless biased, favouring never-smokers [OR 1.87 (95% CI 1.29–2.70)] and tumors of the tonsil [OR 2.30 (1.52–3.47)] or base-of-tongue [OR 1.72 (1.10–2.70)]. These same factors were also associated with p16-positivity [ORs 3.22 (1.27–8.16), 7.26 (3.50–15.1), 5.83 (2.70–12.7), respectively]. Following MI and normalization, the proportion of OPC that was p16-associated rose from 39.8% in 2000 to 65.0% in 2010, p = 0.002, fully explaining the rise in OPC in our patient population. Conclusion The rise in HNSCC referrals seen from 2000 to 2010 at our institution was driven primarily by p16-associated OPC. MI was necessary to derive reliable conclusions when cases with missing data are considerable.     

CD106 Identifies a Subpopulation of Mesenchymal Stem Cells with Unique Immunomodulatory Properties

Mesenchymal stem cells (MSCs) reside in almost all of the body tissues, where they undergo self-renewal and multi-lineage differentiation. MSCs derived from different tissues share many similarities but also show some differences in term of biological properties. We aim to search for significant differences among various sources of MSCs and to explore their implications in physiopathology and clinical translation. We compared the phenotype and biological properties among different MSCs isolated from human term placental chorionic villi (CV), umbilical cord (UC), adult bone marrow (BM) and adipose (AD). We found that CD106 (VCAM-1) was expressed highest on the CV-MSCs, moderately on BM-MSCs, lightly on UC-MSCs and absent on AD-MSCs. CV-MSCs also showed unique immune-associated gene expression and immunomodulation. We thus separated CD106⁺cells and CD106⁻cells from CV-MSCs and compared their biological activities. Both two subpopulations were capable of osteogenic and adipogenic differentiation while CD106⁺CV-MSCs were more effective to modulate T helper subsets but possessed decreased colony formation capacity. In addition, CD106⁺CV-MSCs expressed more cytokines than CD106⁻CV-MSCs. These data demonstrate that CD106 identifies a subpopulation of CV-MSCs with unique immunoregulatory activity and reveal a previously unrecognized mechanism underlying immunomodulation of MSCs.     

Scorpion Venom Heat-Resistant Peptide (SVHRP) Enhances Neurogenesis and Neurite Outgrowth of Immature Neurons in Adult Mice by Up-Regulating Brain-Derived Neurotrophic Factor (BDNF)

Scorpion venom heat-resistant peptide (SVHRP) is a component purified from Buthus martensii Karsch scorpion venom. Although scorpions and their venom have been used in Traditional Chinese Medicine (TCM) to treat chronic neurological disorders, the underlying mechanisms of these treatments remain unknown. We applied SVHRP in vitro and in vivo to understand its effects on the neurogenesis and maturation of adult immature neurons and explore associated molecular mechanisms. SVHRP administration increased the number of 5-bromo-2’-dexoxyuridine (BrdU)-positive cells, BrdU- positive/neuron-specific nuclear protein (NeuN)-positive neurons, and polysialylated-neural cell adhesion molecule (PSA-NCAM)-positive immature neurons in the subventricular zone (SVZ) and subgranular zone (SGZ) of hippocampus. Furthermore immature neurons incubated with SVHRP-pretreated astrocyte-conditioned medium exhibited significantly increased neurite length compared with those incubated with normal astrocyte-conditioned medium. This neurotrophic effect was further confirmed in vivo by detecting an increased average single area and whole area of immature neurons in the SGZ, SVZ and olfactory bulb (OB) in the adult mouse brain. In contrast to normal astrocyte-conditioned medium, higher concentrations of brain-derived neurotrophic factor (BDNF) but not nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF) was detected in the conditioned medium of SVHRP-pretreated astrocytes, and blocking BDNF using anti-BDNF antibodies eliminated these SVHRP-dependent neurotrophic effects. In SVHRP treated mouse brain, more glial fibrillary acidic protein (GFAP)-positive cells were detected. Furthermore, immunohistochemistry revealed increased numbers of GFAP/BDNF double-positive cells, which agrees with the observed changes in the culture system. This paper describes novel effects of scorpion venom-originated peptide on the stem cells and suggests the potential therapeutic values of SVHRP.