The Impact of Social Media on Dietary Behaviors and Body Image of College Students: A Qualitative Approach

Background: The use of social media platforms for health and nutrition information has become popular among college students. Although social media made information readily accessible in different formats, nutritional misinformation promoted by influencers and non-experts caused negative impact on diet behavior and perception of body image. Previous research indicated that extensive use of social media was positively linked to disordered eating behaviors. Social media platforms like Facebook and Instagram that allow users to follow celebrities intensified exposure to influencers’ messages and images and resulted in negative moods and body dissatisfaction. Objective: This paper aims to explore the impact of social media on college students’ dietary behaviors and body image. Participants: 18 undergraduate students from a public university in the Southern United States were recruited through a mass email. Methods: A cross-sectional qualitative study of three focus groups was conducted. The focus groups were based on guiding open-ended questions. Atlas.ti was used to code and analyze the data using inductive and deductive codes. Results: Three main themes were identified. The conditions theme included elements that explain why and how social media influences the participants’ actions. The actions theme included eating behavior, physical activity, and dietary supplement intake. The consequences theme describes anticipated or actual outcomes of actions such as body image and ideal weight. Conclusions: Social media has had a negative influence on diet behaviors and a positive influence on physical activity. Evidence-based nutrition and weight management information is needed to thwart potential misinformation.

The Effects of Zinc Sulfate on the in Vitro Digestibility of Feeds in Cervids

The captive white-tailed deer industry has an estimated impact of 1.6 billion USD in the state of Texas alone. However, nutritional requirements for cervids are determined through research based on sheep and goats. The objective of this study was to determine the effects of zinc on differences in dry matter digestibility in vitro for white-tailed does (Odocoileus virginianus). Deer (n = 2) were ethically harvested, rumens were collected, and placed into a cooler containing warm water. Rumen contents were agitated, and fluid was filtered using cheese cloth while applying CO2. Fluid was placed into four separate incubator jars with filter bags containing a 1:1 alfalfa to coastal hay blend. Zinc doses of 0.073 mg/kg/d equivalents were added to two of the jars ( Zn), and the additional two jars received 0.00 mg/kg/d (CON). Following 48 h of incubation, in vitro true digestibility (IVTD) showed no significant differences between the control and the treatment groups. Average dry matter digested in vitro was 91.87% and 95.13%, respectively. There were no differences detected in ADF, NDF, IVTD, or OM between the treatment groups. While no detectable differences were observed in this study, this methodology did prove to be viable and functional for microbial digestion in vitro. This study can be replicated with multiple experimental units to confirm the observations of increased digestibility. Formal nutritional guidelines can be created to allow for more efficient feeding of cervids thereby reducing feed costs and continuing the growth of the captive deer industry.

Analysis of Growth Characteristics and Differentially Expressed Homologous Genes in Rhodobacter sphaeroides under Normal and Simulated Microgravity Conditions

The term “microgravity” is used to describe the “weightlessness” or “zero-g” circumstances that can only be found in space beyond earth’s atmosphere. Rhodobacter sphaeroides is a gram-negative purple phototroph, used as a model organism for this study due to its genomic complexity and metabolic versatility. Its genome has been completely sequenced, and profiles of the differential gene expression under aerobic, semi-aerobic, and photosynthetic conditions were examined. In this study, we hypothesized that R. sphaeroides will show altered growth characteristics, morphological properties, and gene expression patterns when grown under simulated microgravity. To test that, we measured the optical density and colony-forming units of cell cultures grown under both microgravity and normal gravity conditions. Differences in the cell morphology were observed using scanning electron microscopy (SEM) images by measuring the length and the surface area of the cells under both conditions. Furthermore, we also identified homologous genes of R. spheroides using the differential gene expression study of Acidovorax under microgravity in our laboratory. Growth kinetics results showed that R. sphaeroides cells grown under microgravity experience a shorter log phase and early stationary phase compared to the cells growing under normal gravity conditions. The length and surface area of the cells under microgravity were significantly higher confirming that bacterial cells experience altered morphological features when grown under microgravity conditions. Differentially expressed homologous gene analysis indicated that genes coding for several COG and GO functions, such as metabolism, signal-transduction, transcription, translation, chemotaxis, and cell motility are differentially expressed to adapt and survive microgravity.

Effects of hydrogel-encapsulated bacteria on the healing efficiency and compressive strength of concrete

Microbial-induced calcium carbonate precipitation is a promising technology for self-healing concrete due to its capability to seal microcracks.The main goal of this study was to evaluate the effects of adding hydrogelencapsulated bacteria on the compressive strength and the self-healing efficiency of concrete.To achieve this objective,12 sets of mortar samples were prepared,including three different mineral precursors(magnesium acetate,calcium lactate,and sodium lactate),at two concentrations(67.76 and 75.00 mM/L),and under two different biological conditions(with and without bacteria).In addition,a set of plain mortar samples was prepared to serve as a control.For each sample set,three mortar cubes and three beams were prepared and subjected to compression and flexural strength tests.From the compression tests,it was found that the sample containing calcium lactate along with yeast extract and bacteria displayed the best results.As for the flexural tests,once cracked,the beams were subjected to 28 d of wet/dry cycles(16 h of water immersion and 8 h of drying),where the bottom crack width was monitored(at 0,3,7,14,28 d of wet/dry cycles).Once the sample with the highest healing efficiency was identified(the one containing calcium lactate and hydrogel-encapsulated bacteria),the study was scaled up to concrete specimens.Two sets of concrete cylinders(consisting of three control samples and three samples with bacteria along with calcium lactate)were tested under compression in order to evaluate the effect of the bacteria-precursor combination on the concrete mechanical properties.The samples that yielded the greatest compressive strength were the ones containing calcium lactate and bacteria,displaying an improvement of 17%as compared to the control specimen.Furthermore,a flexural strength recovery analysis was performed on the concrete specimens revealing that the control showed better flexural strength recovery than the bacteriacontaining variant(41.5%vs.26.1%)after 28 d of wet/dry cycles.A healing efficiency analysis was also performed on the cracked samples,revealing that the control displayed the best results.These results are due to the fact that the control specimen showed a narrower crack width in comparison to the bacteria-containing samples.

内存取证研究与进展

网络攻击内存化和网络犯罪隐遁化,使部分关键数字证据只存在于物理内存或暂存于页面交换文件中,这使得传统的基于文件系统的计算机取证不能有效应对.内存取证作为传统文件系统取证的重要补充,是计算机取证科学的重要组成部分,通过全面获取内存数据、详尽分析内存数据,并在此基础上提取与网络攻击或网络犯罪相关的数字证据,近年来,内存取证已赢得安全社区的持续关注,获得了长足的发展与广泛应用,在网络应急响应和网络犯罪调查中发挥着不可替代的作用.首先回顾了内存取证研究的起源和发展演化过程;其次介绍了操作系统内存管理关键机制;然后探讨了内存取证的数据获取和分析方法,归纳总结目前内存取证研究的最新技术;最后讨论了内存取证存在的问题、发展趋势和进一步的研究方向.

基于免疫和代码重定位的计算机病毒特征码提取与检测方法

针对当前感染率高、威胁性极大的感染型计算机病毒,提出了一种基于免疫和代码重定位的计算机病毒特征码提取与检测方法.借鉴生物免疫系统机理,定义了计算机系统中的自体、非自体、抗体、病毒检测器、病毒基因等免疫概念,利用感染型病毒独特的代码重定位特性来提取病毒基因、构建病毒基因库,并在此基础上建立了自体/非自体、病毒基因库和病毒检测器动态演化模型.理论分析与实验结果表明,本方法有效克服了传统方法存在的自体集完备性问题和病毒检测器抗体完整性问题,因而比传统方法有更好的效率与适应性.

灾害管理中供应链问题研究

本文主要研究了自然灾害发生时与供应链相关的问题,诸如居民疏散(交通路线)、信息管理、物资供给与灾害救援问题。旨在通过将供应链管理知识和理念应用于灾害管理中,提出就不可预测的自然灾害做出事先准备和快速反应的战略对策,以提高疏散效率以及对紧急需要的快速反应。

影响RFID技术商业应用的因素分析及启示

随着无线射频识别技术(RFID)的日臻完善和其应用领域的不断扩大,RFID技术在商务领域的应用引起了各国企业和学者的广泛关注。目前欧美发达国家在RFID技术开发及其商业应用方面处于相对领先地位。文章通过对欧美发达国家在商务领域应用RFID技术案例的深入分析,总结不同企业应用RFID技术的成功经验,归纳影响其成败的关键因素,为进一步在我国推广RFID技术的商业应用提供借鉴。

钠离子电池正极材料氟磷酸钒钠研究进展

钠离子电池因其原材料储量丰富、成本低、安全环保等优势在大规模储能、低速电动车领域具有广阔的应用前景。氟磷酸钒钠[Na_(3)V_(2)(PO_(4))_(2)F_(3),NVPF]正极材料具有稳定的三维框架结构、高的理论比容量(128 mA·h/g)和高的工作电压(约3.8 V)等优点,已成为近年来钠离子电池正极材料研究的热点。然而,NVPF较低的电子电导率和较慢的离子扩散速率导致其实际比容量偏低且倍率性能不理想,阻碍了其进一步发展。为此,研究者们通过优化NVPF的合成工艺,并采用包覆、离子掺杂和结构设计等方法对其进行改性,使其电化学性能得到了显著提升,极大增强了NVPF在钠离子电池中的应用潜力。本文通过对近年相关文献的回顾,介绍了NVPF的晶胞特征,并梳理了NVPF的四种脱嵌钠机制(固溶反应机制、分步钠脱嵌机制、三步钠脱嵌机制和两步钠脱嵌机制);简要综述了NVPF常用的三种合成方法(高温固相法、水热法和溶胶-凝胶法),并归纳了各方法的优缺点;详细介绍了利用包覆、离子掺杂和结构设计等方法改性NVPF的研究进展。最后,从实际应用角度出发,对NVPF的合成、改性及其全电池的发展进行了展望,以期推动NVPF正极材料在钠离子电池中的应用化进程。

Past,present and future of cyanide antagonism research:From the early remedies to the current therapies

This paper reviews milestones in antidotal therapies for cyanide(CN) spanning early remedies,current antidotal systems and research towards next generation therapies.CN has been a part of plant defense mechanisms for millions of years.It became industrially important in the nineteenth century with the advent of CN assisted gold mining and the use of CN as a pest control agent.The biochemical basis of CN poisoning was actively studied and key mechanisms were understood as early as 1929.These fundamental studies led to a variety of antidotes,including indirect CN binders that generate methemoglobin,direct CN binders such as hydroxocobalamin,and sulfur donors that convert CN to the less toxic thiocyanate.Research on blood gases at the end of the twentieth century shed new light on the role of nitric oxide(NO) in the body.The discovery of NO's ability to compete with CN for enzymatic binding sites provided a previously missed explanation for the rapid efficacy of NO generating antidotes such as the nitrites.Presently used CN therapies include:methemoglobin/NO generators(e.g.,sodium nitrite,amyl nitrite,and dimethyl aminophenol),sulfur donors(e.g.,sodium thiosulfate and glutathione),and direct binding agents [(e.g.,hydroxocobalamin and dicobalt salt of ethylenediaminetetraacetic acid(dicobalt edetate)].A strong effort is being made to explore novel antidotal systems and to formulate them for rapid administration at the point of intoxication in mass casualty scenarios.New antidotes,formulations,and delivery systems are enhancing bioavailability and efficacy and hold promise for a new generation of improved CN countermeasures.

氯胺酮诱导不同年龄和性别小鼠的过度活动(英文)

虽然氯胺酮(Ketamine)在历史上作为麻醉剂用于人类和家畜,但由于其分解特性,作为一种娱乐药物似乎更具知名度。以前的研究表明相对于成年人,孩子使用氯胺酮不易显示出不利影响,但是对其发生的机理几乎没有研究。本文研究了氯胺酮对小鼠的活动程度和固有行为的作用。结果表明:使用氯胺酮可增加22、35和50日龄小鼠的运动器官的敏捷性,并证明了氯胺酮的作用随年龄的增长而降低;使用氯胺酮所导致的旋转与年龄的变化有关,但站立的减少与年龄无关,这种减少不依赖于小鼠的年龄。

LC-MS/MS analysis of 2-aminothiazoline-4-carboxylic acid as a forensic biomarker for cyanide poisoning

AIM: To demonstrate the potential of using 2-aminothiazoline-4-carboxylic acid(ATCA) as a novel biomarker/forensic biomarker for cyanide poisoning. METHODS: A sensitive method was developed and employed for the identification and quantification of ATCA in biological samples, where the sample extraction and clean up were achieved by solid phase extraction(SPE). After optimization of SPE procedures, ATCA was analyzed by high performance liquid chromatographytandem mass spectrometry. ATCA levels following the administration of different doses of potassium cyanide(KCN) to mice were measured and compared to endogenous ATCA levels in order to study the significance of using ATCA as a biomarker for cyanide poisoning.RESULTS: A custom made analytical method was established for a new(mice) model when animals were exposed to increasing KCN doses. The application of this method provided important new information on ATCA as a potential cyanide biomarker. ATCA concentration in mice plasma samples were increased from 189 ± 28 ng/mL(n = 3) to 413 ± 66 ng/mL(n = 3) following a 10 mg/kg body weight dose of KCN introduced subcutaneously. The sensitivity of this analytical method proved to be a tool for measuring endogenous level of ATCA in mice organs as follows: 1.2 ± 0.1 μg/g for kidney samples, 1.6 ± 0.1 μg/g for brain samples, 1.8 ± 0.2 μg/g for lung samples, 2.9 ± 0.1 μg/g for heart samples, and 3.6 ± 0.9 μg/g for liver samples. CONCLUSION: This finding suggests that ATCA has the potential to serve as a plasma biomarker / forensic biomarker for cyanide poisoning.

The Effects of Different Carbon Sources on the Growth of <i>Rhodobacter sphaeroides</i>

Rhodobacter sphaeroides is a purple non-sulfur bacterium that belongs to the α-3 subdivision of Proteobacteria. R. sphaeroides is a model bacterial species because of its complex genome structure and expanded metabolic capabilities. The genome of R. sphaeroides consists of two circular chromosomes and five endogenous plasmids. It has the ability to grow under a wide variety of environmental conditions. It grows aerobically (~20% O2), semi-aerobically (~2% O2), and photosynthetically (under anaerobic condition plus light). It has been previously shown that many bacterial species utilize a number of alternate carbon sources for their optimal growth under a variety of growth conditions. We hypothesize that different or an additional carbon source in the minimal medium differentially affects the bacterial growth under dark-aerobic conditions. The bacterial growth kinetics and the number of cells in the bacterial culture were analyzed by measuring the optical density (OD at 600 nm) and the colony forming units (CFUs) at regular intervals of bacterial cultures. Results reveal that sodium succinate is the preferred sole carbon source for the optimal growth of R. sphaeroides. The results of growth kinetics and CFUs together concluded that from the tested carbon sources, sodium succinate is the best single carbon source in the minimal media for the optimal growth of R. sphaeroides. Interestingly, cell culture grown in SIS supplemented with sodium acetate exhibits a prolonged lag phase with the lowest ODs and CFUs that later switches to the growth-burst phase support previously discovered similar phenomenon of the growth-rate switch in the presence of acetate metabolism. Future work will utilize the aerobically grown R. sphaeroides’ cells as a biocatalyst to deplete the oxygen levels from natural gas streams and industrial gas pipelines.

The Horizontal Loop Electromagnetic(HLEM)Response of Ifewara Transcurrent Fault,Southwestern Nigeria:A Computational Results

The need to accurately interpret geological models that approximate mineralized zones in a Basement Complex terrain necessitate the development of horizon loop electromagnetic method(HLEM)forward modeling solutions for such scenarios.The focus of the present work is on finding rapid forward modeling solutions for synthetic HLEM data as an aid in exploration for moderate to deep conductive mineral exploration targets.The main thrust is obtaining idealized HLEM models that are required for geological interpretation of the subsurface in such environment.The original HLEM equations developed by Wesley were extended to represent a horizontally stratified earth with a conductive approximated by shear zone.From these equations a computer program was written to calculate the HLEM responses for optimal conductor model with known values of coil separations(L),depth of burial(z)and angle of dip of the target.The thin conductive model was used because it is simple and suitable for different geological scenarios.The accuracy of the approximate forward solution has been confirmed for HLEM systems with various geometric ranges,frequencies and conductivities.Three models having varying overburden thickness,dip angle of target and source-receiver separation were used in the forward modeling.The effect of varying the dip angle,overburden thickness and coil separation was studied in all the three models used.The result obtained from the forward modeling showed that variation of the dip angle gave rise to changes in the amplitudes of the anomalies generated,while that of overburden and coil separation gave rise to changes in anomaly shape.Also,the geometry and position of the causative body were precisely delineated.

Neurotherapy for chronic headache following traumatic brain injury

Background: Chronic headache following traumatic brain injury(TBI) sustained in military service, while common, is highly challenging to treat with existing pharmacologic and non-pharmacologic interventions, and it may be complicated by co-morbid posttraumatic stress. Recently, a novel form of brainwave-based intervention known as the Flexyx Neurotherapy System(FNS), which involves minute pulses of electromagnetic energy stimulation of brainwave activity, has been suggested as a means to address symptoms of TBI. This study reports on a clinical series of patients with chronic headache following service-connected TBI treated with FNS.Methods: Nine veterans of the wars in Afghanistan and Iraq with moderate to severe chronic headaches following service-connected TBI complicated by posttraumatic stress symptoms were treated in 20 individual FNS sessions at the Brain Wellness and Biofeedback Center of Washington(in Bethesda, Maryland, USA). They periodically completed measures including the Brief Pain Inventory-Headache(BPI-HA), previous week worst and average pain ratings, the Posttraumatic Stress Disorder Checklist-Military version(PCL-M), and an individual treatment session numerical rating scale(NRS) for the degree of cognitive dysfunction. Data analyses included beginning-to-end of treatment t-test comparisons for the BPI-HA, PCL-M, and cognitive dysfunction NRS. Results: All beginning-to-end of treatment t-test comparisons for the BPI-HA, PCL-M, and cognitive dysfunction NRS indicated statistically significant decreases. All but one participant experienced a reduction in headaches along with reductions in posttraumatic stress and perceived cognitive dysfunction, with a subset experiencing the virtual elimination of headaches. One participant obtained modest headache relief but no improvements in posttraumatic stress or cognitive dysfunction. Conclusions: FNS may be a potentially efficacious treatment for chronic posttraumatic headache sustained in military service. Further research is needed to investigate the efficacy of FNS within a randomized, controlled clinical trial to identify the characteristics of those most likely to respond and to explore underlying mechanisms that may contribute to improvements.

Evolution of PE35 and PPE68 Gene Families in Mycobacterium: Roles of Horizontal Gene Transfer and Evolutionary Constraints

Mycobacterium is a genus of bacteria with over a hundred non-pathogenic and pathogenic species, best recognized for certain members known to cause diseases such as tuberculosis and leprosy. Two novel protein families important in the pathogenesis of Mycobacterium species are the PE and PPE families. These two protein families affect the antigenic profiles, disturbing host immunity. To better understand the origin and evolution of these gene families and the differences in their composition between pathogenic and non-pathogenic strains, several bioinformatic analyses were conducted both among Mycobacterium and closely related species that contain PE35 and PPE68 gene homologs. The methods included protein homology searches (BLASTP), horizontal gene transfer analysis (IslandViewer), phylogenetic analysis, gene cluster analysis and structural and functional constraints. Results revealed that PE and PPE gene homologs were not only limited to Mycobacterium, but also existed in three other non-mycobacterial genera, Rhodococcus, Tsukamurella and Segniliparus, and were possibly initially acquired from non-mycobacterial microorganisms by multiple horizontal gene transfers. Results also demonstrated that PE and PPE genes were more diverse and more rapidly evolving in pathogenic Mycobacterium as compared with non-pathogenic Mycobacterium and other non-mycobacterial species. These findings possibly shed light on the diverse functions and origins of the PE/PPE proteins among these organisms.

Cellular Localization of Gold and Mechanisms of Gold Resistance in <i>Rhodobacter sphaeroides</i>

Heavy metal pollution is a worldwide problem with many associated health risks, including bone loss, kidney damage, and several forms of cancer. There is a great need of bioremediation of these toxic metals from the environment, as well as implementing a monitoring system to control the spreading pollution. This study focuses on the bioremediation potential of Rhodobacter sphaeroides in the presence of the toxic gold chloride (AuCl3). Growth characteristics of the bacterial cells exposed to a range of toxic gold concentrations were analyzed through the growth kinetics and the colony forming units under aerobic, photosynthetic, and anaerobic growth conditions. The localization of the gold particles within two cellular fractions, cytoplasm and the plasma membrane, are analyzed using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Results of this study demonstrated the photosynthetic growth condition as best suited for the metal tolerance, compared to the aerobic and anaerobic growth conditions. Results also revealed the overall accumulation and localization of gold particles, while not different between the membrane and the cytoplasmic fractions increased at different concentrations of the gold contamination. The results of the localization under photosynthetic growth condition revealed the accumulation reached the highest very quickly, and an overall shift in localization of the gold particles from an equal distribution to an increase within the membrane fraction at the highest concentrations of gold contamination. The localization of the gold particles was validated by Transmission Electron Microscopy (TEM) where the results confirmed the increase in accumulation within the membrane, and photosynthetic membranes, of R. sphaeroides.

CtrA Is Nonessential for Cell Cycle Regulation in <i>Rhodobacter sphaeroides</i>

The bacterial cell cycle consists of a series of genetically coordinated biochemical and biophysical events. In Caulobacter crescentus, CtrA is an essential cell cycle regulator that modulates many cell cycle processes. In the present study, the role of the CtrA was investigated in Rhodobacter sphaeroides 2.4.1 by employing genetic, molecular, and bioinformatic approaches. Examination of the ctrA-null mutant revealed that the loss of CtrA did not affect growth characteristics and cell morphology in R. sphaeroides when grown under aerobic or photosynthetic growth conditions but slower growth was noticed in the anaerobic-dark-DMSO condition. Phylogenetic analyses demonstrated that CtrA has diversified its role in major lineages of α-Proteobacteria and has possibly been involved in adaptation to variable lifestyles. Analysis of the CtrA binding sites in the R. sphaeroides genome suggests that CtrA may regulate 127 genes involving different cellular processes. Protein homology searches revealed that only a small number of ctrA-regulated genes are homologous across C. crescentus, R. capsulatus, and R. sphaeroides. Comparison of the functions of putative ctrA-regulated genes in C. crescentus, R. capsulatus, and R. sphaeroides revealed that all three species possessed broad pathway control across a variety of cluster of orthologous gene functions (COGs). However, interestingly, it seems that the essentiality of CtrA in C. crescentus may depend more on the selective control that it exerts on a few critical cell cycle genes and pathways that are not controlled by CtrA in a similar fashion in R. capsulatus and R. sphaeroides.

Multiple Chromosomes in Bacteria: Low Level of Evolutionary Constraint Drives the Rapid Genetic Divergence of Chromosome II

Multiple chromosomes in bacteria are designated as a larger primary chromosome (CI) and smaller accessory chromosomes (CII and CIII). Although previous studies examined multiple chromosomes in several bacterial species, the evolutionary mechanisms for the origin of CIIs still remain unclear. In this study, the four following hypotheses were tested. 1) CIIs exhibit lower sequence conservation and sequence divergence compared to their corresponding CIs across species of Proteobacteria. 2) The differential sequence divergence of CI and CII depends on pathogenic and non-pathogenic lifestyles. 3) CIIs harbor a higher level of horizontal gene transfers (HGTs) than CIs. 4) Orthologs located on CIIs experience less purifying selection than their corresponding orthologs on CIs. Results reveal a higher level of sequence conservation of CIs than the sequence conservation of CIIs. There is no significant difference in HGT estimates between CIs and CIIs. A majority of orthologous genes of CIs and CIIs experience purifying selection;however, genes on CIIs were significantly less constrained than the corresponding ones on CIs. This finding is true for both pathogenic and non-pathogenic bacteria, but the selective constraints for non-pathogenic bacteria are relatively less constrained. It was concluded that the differential selective constraint is a potent driving force for the rapid evolution of CII. Therefore, gene expression analysis at the transcriptome and proteome levels may shed light on the gene regulation mechanisms that might affect the sequence divergence between CI and CII.

Organization, expression and evolution of flagellar genesin <i>Rhodobacter sphaeroides </i>2.4.1

Rhodobacter sphaeroides 2.4.1 belongs to the?-3 subdivision of the Proteobacteria. It possesses a multipartite genome structure consisting of two circular chromosomes, andit displays a wide range of metabolic diversity.Approximately 40 flagellar proteins are required for structure, assembly, and regulation of the flagellum formation in most bacterial species. R. sphaeroidescontains two flagellar gene clusters (fla1 and fla2),which encode 38 and 21 proteins, respectively. Thirty-six of these genes exist in duplicate gene-pairs.A combination of genome analysis, phylogenetic analysis and mRNA expression analysis were employed to examine the conservation of structure, function and evolution of fla1 and fla2 in R. sphaeroides. The results demonstrated that fla2, which was shared among members of ?-Proteobacteria, is native toR. sphaeroides, while fla1 was horizontally transferred from a member of ?-Proteobacteria.In addition, genes located in fla1 are expressed over several growth conditions, but those in fla2 are barely expressed.