Application of a competition model to the growth of Streptococcus mutans and Streptococcus sanguis in binary continuous culture.

Streptococcus mutans 6715-15 and Streptococcus sanguis 10558 were grown together in continuous culture with glucose as the limiting carbon source. The relationship of growth rate to substrate concentration was determined for pure cultures of each organism in continuous and batch cultures. A model based on competition for a growth-limiting substrate (glucose) was used to predict the proportions of each organism when grown in binary cultures. The results indicate that interactions other than competition for glucose carbon exist between S. mutans and S. sanguis grown under these conditions.     

Autolytic proteolysis within the function to find domain (FIIND) is required for NLRP1 inflammasome activity

Nucleotide-binding domain leucine-rich repeat proteins (NLRs) play a key role in immunity and disease through their ability to modulate inflammation in response to pathogen-derived and endogenous danger signals. Here, we identify the requirements for activation of NLRP1, an NLR protein associated with a number of human pathologies, including vitiligo, rheumatoid arthritis, and Crohn disease. We demonstrate that NLRP1 activity is dependent upon ASC, which associates with the C-terminal CARD domain of NLRP1. In addition, we show that NLRP1 activity is dependent upon autolytic cleavage at Ser(1213) within the FIIND. Importantly, this post translational event is dependent upon the highly conserved distal residue His(1186). A disease-associated single nucleotide polymorphism near His(1186) and a naturally occurring mRNA splice variant lacking exon 14 differentially affect this autolytic processing and subsequent NLRP1 activity. These results describe key molecular pathways that regulate NLRP1 activity and offer insight on how small sequence variations in NLR genes may influence human disease pathogenesis.     

Comparison of five commercial DNA extraction kits for the recovery of Yersinia pestis DNA from bacterial suspensions and spiked environmental samples

Aim:  To evaluate commercial DNA extraction kits for their ability to isolate DNA from Yersinia pestis suspensions and spiked environmental samples.
Methods and Results:  Five commercially available DNA extraction kits were evaluated: the ChargeSwitch gDNA Mini Bacteria Kit, the IT 1-2-3 Sample DNA Purification Kit, the MasterPure Complete DNA and RNA Purification Kit, the QIAamp DNA Blood Mini Kit and the UltraClean Microbial DNA Isolation Kit. The extraction methods were performed upon six Y. pestis strains and spiked environmental specimens, including three swab types and one powder type. Taqman real-time PCR analysis revealed that the use of the MasterPure kit resulted in DNA with the most consistently positive results and the lowest limit of detection from Y. pestis suspensions and spiked environmental samples.
Conclusion:  Comparative evaluations of the five commercial DNA extraction methods indicated that the MasterPure kit was superior for the isolation of PCR-amplifiable DNA from Y. pestis suspensions and spiked environmental samples.
Significance and Impact of the Study:  The results of this study can assist diagnostic laboratories with selecting the best extraction method for processing environmental specimens for subsequent detection of Y. pestis by real-time PCR.     

Binding of the Novel Serotonin Agonist 8-Hydroxy-2-(Di-n-Propylamino) Tetralin in Normal and Alzheimer Brain

Binding of [3H]8-hydroxy-2-(di-n-propylamino) tetralin, a putative ligand for the 5-hydroxytryptamine (5-HT, serotonin) 1A recognition site, was measured in neocortex from postmortem human brain. The substance was found to bind to a saturable site with a KD value and pharmacological profile similar to that of rat. Binding to membranes from normal human temporal cortex was found to significantly correlate (inversely) with age. A significant reduction in binding, reflecting decreased density of recognition sites, was observed in the frontal cortex of patients with Alzheimer's disease (48% loss). This region in the dement brains showed unaltered presynaptic 5-HT function (5-HT and 5-hydroxyindoleacetic acid content) whereas 5-HT concentration was reduced in the temporal cortex.     

秋葵AeMYB1R1转录因子基因克隆及对胁迫的响应北大核心CSCD

MYB转录因子家族广泛参与了植物对干旱、盐渍、冷害等非生物胁迫的应答。为了深入研究秋葵[Abelmoschus esculentus(L.) Moench]中的MYB类转录因子,该研究以‘北海道1号’秋葵为研究对象,采用PCR方法克隆AeMYB1R1基因,并借助生物信息学进行特征分析;采用qRT-PCR荧光定量方法分析其表达模式及其在非生物胁迫下的表达特性。结果表明:(1)成功克隆获得1个秋葵AeMYB1R1基因;该基因包含1个1 056 bp的开放阅读框,编码352个氨基酸;序列对比和系统进化树结果显示,AeMYB1R1在植物进化过程中具有较高的保守性;AeMYB1R1蛋白分子量为37 891.57 Da,等电点为8.75,含有较多的谷氨酸和较少的色氨酸,以及较多潜在的磷酸化位点和糖基化位点。(2)结构分析显示,AeMYB1R1蛋白主要由α螺旋和无规则卷曲构成,无信号肽和跨膜结构,为疏水性蛋白;同时,氨基酸序列在第104至第156位含有一个保守结构域,表明其属于SHAQKYF类MYB家族转录因子。(3)qRT-PCR结果显示,AeMYB1R1基因在秋葵叶中的表达量最高,其次是根和茎,具有组织表达特性;与高温和低温胁迫相比,在盐胁迫和干旱胁迫中AeMYB1R1表达量更高,说明AeMYB1R1可能是秋葵抗盐和抗旱的关键转录因子。研究结果为AeMYB1R1基因在秋葵生长发育和抗逆机制中的功能研究奠定了理论依据。     

The effects of prostalene and alfaprostol as uterine myotonics, and the effect on postpartum pregnancy rate in the mare following daily treatment with prostalene

The effects of oxytocin and two prostaglandin (PG) F(2)alpha analogues, prostalene and alfaprostol, on uterine pressure in the mare were measured using balloon-tipped catheters connected to pressure transducers. The PGF(2)alpha analogues caused increased uterine pressure beginning 7 to 15 min postinjection and persisting for the duration of each 60 min recording session. Forty postpartum mares of light-horse breed were used to evaluate the effects of prostalene on postpartum pregnancy rate. Eighteen mares were injected by aseptic technique subcutaneously with 1 mg prostalene twice daily, beginning on the day of foaling (Day 0) and continuing for 10 consecutive days (Day 10) or until the mare was first bred at foal heat. Twenty-two postpartum mares were injected with 1.0 ml sterile saline by the same technique as the controls. Of treated mares, 76.9% were diagnosed pregnant after breeding versus 44.4% of the control mares (P = 0.07). Of treated mares, 66.7% bred at their second postpartum estrus became pregnant versus 28.6% of control mares (P = 0.03). Prostalene, given at 1 mg twice daily for 10 d postpartum, produced an increased pregnancy rate after both foal heat and second postpartum estrus breedings in the mare.     

火干扰对小兴安岭毛赤杨沼泽温室气体排放动态影响及其影响因素

利用静态箱-气相色谱法,对小兴安岭轻度火烧毛赤杨沼泽CH4、CO2、N2O生长季排放通量进行研究.结果表明:火烧使毛赤杨沼泽生长季CH4排放通量提高485.2％,CO2和N2O排放通量分别下降45.5％、24.8％.火烧未改变CH4季节性排放规律,但改变了CO2、N2O季节性变化规律.火烧样地CH4排放通量与土壤15cm温度间存在显著正相关性关系而与水位相关性不显著,火烧样地CO2排放与土壤0-30 cm温度呈显著或极显著正相关,与水位极显著负相关.对照样地CO2排放通量与土壤0-15 cm温度呈显著或极显著正相关,与水位极显著负相关,火烧使毛赤杨沼泽CH4排放源的强度增强,CO2、N2O的排放消弱,全球温室潜势下降约为43.34％.     

Cutting edge: bacterial modulation of epithelial signaling via changes in neddylation of cullin-1

The human enteric flora plays a significant role in intestinal health and disease. Certain enteric bacteria can inhibit the NF-kappaB pathway by blockade of IkappaB-alpha ubiquitination. IkappaB-alpha ubiquitination is catalyzed by the E3-SCF(betaTrCP) ubiquitin ligase, which is itself regulated via covalent modification of the cullin-1 subunit by the ubiquitin-like protein NEDD8. Neddylation is a biochemical event associated with diverse cellular processes related to cell signaling, however, physiological regulation of cullin neddylation has not been described in mammalian systems. We report that interaction of nonpathogenic bacteria with epithelial cells resulted in a rapid loss of neddylated Cul-1 and consequent repression of the NF-kappaB pathway. This observation may explain the ability of intestinal bacterial communities to influence diverse eukaryotic processes in general and inflammatory tolerance of the mammalian intestinal epithelia specifically.