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Riondet C Cachon R Waché Y Sunyol i Bert E Gbaguidi P Alcaraz G Diviès C 《Applied microbiology and biotechnology》2000,53(4):476-479
The combined effect of redox potential (RP) (from −200 to 500 mV) and pH (from 5.0 to 7.0) on the heat resistance and growth
recovery after heat treatment of Escherichia coli was tested. The effect of RP on heat resistance was very different depending on the pH. At pH 6.0, there was no significant
difference, whereas at pH 5.0 and 7.0 maximum resistance was found in oxidizing conditions while it fell in reducing ones.
In sublethally heat-damaged cells, low reducing and acid conditions allowed growth ability to be rapidly regained, but a decrease
in the redox potential and pH brought about a longer lag phase and a slower exponential growth rate, and even led to growth
failure (pH 5.0, ≤−100 mV).
Received: 28 June 1999 / Received revision: 22 October 1999 / Accepted: 22 October 1999 相似文献
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In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongoing research of regenerative medicine using stem cells and concurrent advancement in biotechnology have shifted the focus from surgical reconstruction to a novel stem cell-based tissue engineering strategy for customized and functional craniofacial bone regeneration. Given the unique ontogenetical and cell biological properties of perinatal stem cells, emerging evidence has suggested these extraembryonic tissue-derived stem cells to be a promising cell source for extensive use in regenerative medicine and tissue engineering. In this review, we summarize the current achievements and obstacles in stem cell-based craniofacial bone regeneration and subsequently we address the characteristics of various types of perinatal stem cells and their novel application in tissue engineering of craniofacial bone. We propose the promising feasibility and scope of perinatal stem cell-based craniofacial bone tissue engineering for future clinical application. 相似文献
24.
BH3‐in‐groove dimerization initiates and helix 9 dimerization expands Bax pore assembly in membranes 下载免费PDF全文
Zhi Zhang Hetal Brahmbhatt Samson GF Condon Suzanne M Lapolla Franklin A Hays Jingzhen Ding Feng He Xuejun C Zhang Jianing Li Alessandro Senes David W Andrews Jialing Lin 《The EMBO journal》2016,35(2):208-236
Pro‐apoptotic Bax induces mitochondrial outer membrane permeabilization (MOMP) by forming oligomers through a largely undefined process. Using site‐specific disulfide crosslinking, compartment‐specific chemical labeling, and mutational analysis, we found that activated integral membrane Bax proteins form a BH3‐in‐groove dimer interface on the MOM surface similar to that observed in crystals. However, after the α5 helix was released into the MOM, the remaining interface with α2, α3, and α4 helices was rearranged. Another dimer interface was formed inside the MOM by two intersected or parallel α9 helices. Combinations of these interfaces generated oligomers in the MOM. Oligomerization was initiated by BH3‐in‐groove dimerization, without which neither the other dimerizations nor MOMP occurred. In contrast, α9 dimerization occurred downstream and was required for release of large but not small proteins from mitochondria. Moreover, the release of large proteins was facilitated by α9 insertion into the MOM and localization to the pore rim. Therefore, the BH3‐in‐groove dimerization on the MOM nucleates the assembly of an oligomeric Bax pore that is enlarged by α9 dimerization at the rim. 相似文献
25.
We are beginning to uncover common mechanisms leading to the evolution of biological networks. The driving force behind these
advances is the increasing availability of comparative data in several species. 相似文献
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Ke Lin Ningwen Zhang Edouard I Severing Harm Nijveen Feng Cheng Richard GF Visser Xiaowu Wang Dick de Ridder Guusje Bonnema 《BMC genomics》2014,15(1)
Background
Brassica rapa is an economically important crop species. During its long breeding history, a large number of morphotypes have been generated, including leafy vegetables such as Chinese cabbage and pakchoi, turnip tuber crops and oil crops.Results
To investigate the genetic variation underlying this morphological variation, we re-sequenced, assembled and annotated the genomes of two B. rapa subspecies, turnip crops (turnip) and a rapid cycling. We then analysed the two resulting genomes together with the Chinese cabbage Chiifu reference genome to obtain an impression of the B. rapa pan-genome. The number of genes with protein-coding changes between the three genotypes was lower than that among different accessions of Arabidopsis thaliana, which can be explained by the smaller effective population size of B. rapa due to its domestication. Based on orthology to a number of non-brassica species, we estimated the date of divergence among the three B. rapa morphotypes at approximately 250,000 YA, far predating Brassica domestication (5,000-10,000 YA).Conclusions
By analysing genes unique to turnip we found evidence for copy number differences in peroxidases, pointing to a role for the phenylpropanoid biosynthesis pathway in the generation of morphological variation. The estimated date of divergence among three B. rapa morphotypes implies that prior to domestication there was already considerably divergence among B. rapa genotypes. Our study thus provides two new B. rapa reference genomes, delivers a set of computer tools to analyse the resulting pan-genome and uses these to shed light on genetic drivers behind the rich morphological variation found in B. rapa.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-250) contains supplementary material, which is available to authorized users. 相似文献27.
Jude D Bigoga Lucien Manga Vincent PK Titanji Maureen Coetzee Rose GF Leke 《Malaria journal》2007,6(1):5
Background
Malaria is a major public health problem in Cameroon. Unlike in the southern forested areas where the epidemiology of malaria has been better studied prior to the implementation of control activities, little is known about the distribution and role of anophelines in malaria transmission in the coastal areas.Methods
A 12-month longitudinal entomological survey was conducted in Tiko, Limbe and Idenau from August 2001 to July 2002. Mosquitoes captured indoors on human volunteers were identified morphologically. Species of the Anopheles gambiae complex were identified using the polymerase chain reaction (PCR). Mosquito infectivity was detected by the enzyme-linked immunosorbent assay and PCR. Malariometric indices (plasmodic index, gametocytic index, parasite species prevalence) were determined in three age groups (<5 yrs, 5–15 yrs, >15 yrs) and followed-up once every three months.Results
In all, 2,773 malaria vectors comprising Anopheles gambiae (78.2%), Anopheles funestus (17.4%) and Anopheles nili (7.4%) were captured. Anopheles melas was not anthropophagic. Anopheles gambiae had the highest infection rates. There were 287, 160 and 149 infective bites/person/year in Tiko, Limbe and Idenau, respectively. Anopheles gambiae accounted for 72.7%, An. funestus for 23% and An. nili for 4.3% of the transmission. The prevalence of malaria parasitaemia was 41.5% in children <5 years of age, 31.5% in those 5–15 years and 10.5% in those >15 years, and Plasmodium falciparum was the predominant parasite species.Conclusion
Malaria transmission is perennial, rainfall dependent and An. melas does not contribute to transmission. These findings are important in the planning and implementation of malaria control activities in coastal Cameroon and West Africa.28.
G.Franck Gbaguidi Luis B Agellon 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2002,1583(2):229-236
Cholesterol 7α-hydroxylase (cyp7a) mediates cholesterol elimination in the liver by catalyzing the first and rate-limiting step in the conversion of cholesterol into bile acids. Peroxisome proliferator-activated receptor α (PPARα; NR1C1) and liver X receptor α (LXRα; NR1H3) are two nuclear receptors that stimulate the murine Cyp7a1 gene. Here we report that co-expression of PPARα and LXRα in hepatoma cells abolishes the stimulation of Cyp7a1 gene promoter in response to their respective agonists. PPARα and LXRα form an atypical heterodimer that binds to two directly adjacent hexameric sequences localized within overlapping PPARα and LXRα response elements (termed Site I), antagonizing the interaction of PPARα:retinoid X receptor α (RXRα) or RXRα:LXRα with the Cyp7a1 gene promoter. Mutations within either hexameric sequences that specifically abolished LXRα:PPARα heterodimer binding to the murine Cyp7a1 Site I also relieved promoter inhibition. The LXRα:PPARα heterodimer may be important in coordinating the expression of genes that encode proteins involved in metabolism of fats and cholesterol. 相似文献
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Safiou B. Adehan Hassane Adakal Donald Gbinwoua Daté Yokossi Sébastien Zoungrana Patrice Toé Mathieu Ouedraogo A. Michel Gbaguidi Camus Adoligbé A. Belarmin Fandohan Gildas Hounmanou Romain Glèlè Kakaï Souaïbou Farougou Eva M. De Clercq 《EcoHealth》2018,15(2):437-449
Worldwide, cattle production is struggling to face the negative impacts caused by ticks and Rhipicephalus (Boophilus) microplus is one of the most harmful ticks for livestock. Most of the people in West Africa depend on cattle farming and subsistence agriculture. The presence of ticks on cattle is a major problem faced by smallholder farmers who fight for their livelihood. National and regional tick control programs could assist these rural communities in protecting their livelihoods against ticks and tick-borne diseases, but only if they take into account the targeted herders and their perception on cattle management and tick control. This paper aims to provide a better insight in the socio-economic characteristics of Beninese cattle farmers, and their perception on tick burden, as well as to document common tick control strategies. Different tick species and their seasonality are well understood by cattle herders. For tick control, many still use manual tick removal, especially in the north of the country. The high cost of acaricides, the lack of financial means of African farmers, and of the local stockbreeders in particular, limits the use of acaricides in livestock breeding in Benin. While aiming to increase the meat or milk production of their animals, stockbreeders who can afford it sometimes turn to an abusive use of acaricides, which might in time lead to an increase in tick resistance. This study remains one of the rare studies to report extensively on the perceptions of West African cattle herders. 相似文献
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Bjorn Kloosterman AM Anithakumari Pierre-Yves Chibon Marian Oortwijn Gerard C van der Linden Richard GF Visser Christian WB Bachem 《BMC plant biology》2012,12(1):17