New mobile DNA element in Wolbachia may contribute to improved disease control

first_imgReviewed by James Ives, M.Psych. (Editor)Mar 21 2019Controlling mosquito-borne illnesses, such as Dengue or West Nile virus, has historically been difficult due to a lack of effective vaccines and concerns about the environmental impact of insecticides. Thus, scientists have turned to manipulating Wolbachia, a parasitic bacterium within mosquitoes, as a way to control the reproductive fitness of mosquito populations that transmit human disease.In a new study in Nature Communications, an international team including scientists from the Marine Biological Laboratory (MBL) and the University of Chicago identified a new mobile DNA element in Wolbachia, which may contribute to improved control strategies for mosquito vectors of disease.Led by Julie Reveillaud of INRA, France, and Sarah Bordenstein of Vanderbilt University, the researchers reconstructed near-complete genomes of Wolbachia isolated from individual ovaries of four Culex pipiens mosquitoes. In the process, they identified a novel plasmid — a circular piece of DNA that can replicate independently of the chromosomes. A plasmid is a mobile DNA element, meaning it can transfer from one cell to another and can have great implications for the fitness and evolution of a microbial species. Due to the ability of mobile genetic elements to spread through different Wolbachia cells, and thus across a Wolbachia population, they hold promise for controlling mosquito populations that may carry disease.”Our data show that this novel plasmid is widespread across natural Wolbachia populations that infect C. pipiens mosquitoes throughout the world, which implies it has an essential role. The idea that it may enable transformation of the Wolbachia populations is simply very exciting,” says the senior author of the study, A. Murat Eren (Meren), an assistant professor of medicine at the University of Chicago and an MBL Fellow.Wolbachia is transmitted from mother to offspring and can influence the reproductive behavior of its mosquito host. Wolbachia can modify sperm so if an infected male mates with an uninfected female, or with one that carries a different strain of Wolbachia, embryos cannot develop. The mechanism behind this embryonic killing lies within another mobile genetic element in the Wolbachia genome.”Wolbachia populations do not lend themselves to direct genetic modification. While a natural plasmid sounds very promising to bypass those limitations, we do not yet have any evidence to suggest the possibility or efficacy of any transformation through this plasmid,” Meren says. “We just discovered its existence, and the time will tell how useful it is.”Related StoriesTexas Biomed awarded $2 million DOD grant to study promising Zika vaccineNew study suggests bacteria-loaded mosquitoes may halt spread of Dengue feverFDA approves first vaccine for prevention of dengue disease in endemic regions”Other exciting questions for which we do not have yet clear answers include whether there is an ancestral relationship between the plasmid and other mobile genetic elements of Wolbachia, and whether these interact or not,” adds Reveillaud.This collaboration began at MBL in 2011, when Meren and Reveillaud brought their computational and molecular evolution backgrounds together to explore questions in microbial ecology in the MBL’s Bay Paul Center. (See Reveillaud’s blog post about the collaboration.) Years later, they began examining Wolbachia genomic diversity by focusing on individual mosquitoes captured in the wild, rather than using laboratory mosquito strains. With the help of former MBL scientists Sarah Bordenstein and Seth Bordenstein of Vanderbilt University, who have expertise in Wolbachia, they began unraveling the intricacies of the Wolbachia genome.”Wolbachia is particularly difficult to study because, unlike free-living bacteria, it cannot be cultured in cell-free media. Through this interdisciplinary collaboration, we were able to tease apart the genomes of the mosquito host, Wolbachia, and its mobile elements,” says Sarah Bordenstein.While fragments of this novel plasmid had appeared in previous Wolbachia sequencing studies, these fragments had never been assembled into a complete circular piece and its extrachromosomal nature was not recognized, most likely due to computational limitations. The team was able to overcome these limitations by employing a combination of cutting-edge strategies, such as genome-resolved metagenomics and long-read sequencing.”The key bioinformatics platform that enabled us to study mosquito metagenomes and Wolbachia pangenomes in this study, and the connections between scientists with distinct skills that made this discovery possible, were developed at the MBL,” Meren says. “Almost everyone in this paper is somehow linked to the MBL.”Source: https://www.mbl.edu/blog/new-mobile-element-found-in-mosquito-parasite-has-potential-for-disease-control/last_img read more

Japanese researchers explain how inflammation causes gastric tumors

first_imgReviewed by Kate Anderton, B.Sc. (Editor)Apr 16 2019In 1982, researchers reported a link between chronic gastritis and stomach bacterium Helicobacter pylori, triggering a flurry of research into this newly-identified pathogen. These studies made it clear that in addition to its involvement in gastritis, H. pylori was a significant factor in the development of both peptic ulcers and gastric cancer. But while the link between the bacterium and disease was clear-cut, exactly how H. pylori caused gastric tumors remained the subject of much debate.Now, almost four decades later, researchers from Kanazawa University and the Japan Agency for Medical Research and Development have finally shown how inflammation caused by H. pylori infection causes the proliferation of gastric epithelial stem cells, leading to gastric tumors.In a report published recently in cancer genetics journal Oncogene, the researchers describe how they built on previous findings to solve the mystery.”We previously showed that tumor necrosis factor alpha (TNF-α), a cytokine that causes inflammation, promotes gastric tumor formation by activating a protein called NOXO1,” says lead author of the study Dr Kanae Echizen. “What we didn’t know was exactly how NOXO1 induces tumor formation in the stomach.”Related StoriesHow cell-free DNA can be targeted to prevent spread of tumorsUsing machine learning algorithm to accurately diagnose breast cancerStudy: Nearly a quarter of low-risk thyroid cancer patients receive more treatment than necessaryNOXO1 is a component of the NOX1 complex, which produces tissue-damaging molecules called reactive oxygen species (ROS). ROS, or more accurately, the oxidative stress caused by these molecules, can result in mutations in the DNA of stomach cells, leading to tumor formation. Inflammation caused by H. pylori infection also produces ROS, increasing oxidative stress in the stomach.In the newly-published study, the research team showed that inflammation caused excess production of NOX1-complex proteins in response to signals from NF-κB, a regulatory protein that turns on genes to combat stress or bacterial infection, and which is a major player in the inflammatory response. However, most importantly, they found that NOX1/ROS signaling caused gastric epithelial stem cells to multiply uncontrollably, resulting in tumor formation.Knowing this, the researchers used a drug to suppress the activity of the NOX1 complex, which immediately halted the growth of gastric cancer cells. Even more excitingly, disruption of Noxo1 in a mouse gastritis model stopped the proliferation of epithelial stem cells.”We have finally been able to show that inflammation enhances the expression of NOXO1, which induces the proliferation of gastric epithelial stem cells, leading to gastric tumors,” explains Dr Masanobu Oshima, senior author of the study. “Gastric cancer is the fourth most common cancer worldwide and has the second highest mortality rate. If we can disrupt the NOX1/ROS signaling pathway in situ, we may be able to prevent the development of this aggressive disease.”Source: https://www.kanazawa-u.ac.jp/latest-research/66821last_img read more

Kerala High Court refuses to intervene in Sabarimala caseKerala High Court refuses

first_imgSHARE A PIL had sought temporary ban on entry of women of all ages into the temple COMMENTS  The Kerala High Court on Thursday refused to intervene in the Sabarimala row or stay the Supreme Court’s (SC) order that allows entry of women of all ages into the temple.The refusal came in response to a public interest litigation (PIL) which sought a temporary ban on the order till the Apex court considers a batch of review petitions on November 13.Original orderA Division Bench headed by the Chief Justice of the High Court observed it cannot intervene in the matter since the original order had been pronounced by the SC.It appreciated the efforts of the State government in implementing the order.Meanwhile, the State unit of the BJP in Kochi on Thursday discussed the modus operandi for sustaining the protests against the SC’s verdict.The core committee met ahead of a wider discussions on the conduct of the six-day rath yatra announced by the BJP from Kasaragod, the northern-most district, to Pathanamthitta, the district where the hill shrine is located.The yatra will begin on November 8 and end on the 13th.Apart from the State-level leaders, representatives from the Parliamentary constituencies will also take part in the meeting, sources in the party said.Prospects of ‘shepherding elements within the Congress party’, who are disgruntled with the party’s stance over Sabarimala, were also reportedly discussed in the meeting. Meanwhile in Kottayam, a conference of various Hindu organisations decided to intensify the protests against the implementation of the SC verdict.In the meeting it was alleged that the State government is trying to put pressure on the devotees to stay back and not proceed with the pilgrimage.Mobilising supportThe decision to conduct ‘Sarana Ghosha Parikramas’ (prayer and chant processions) in all villages in the State on November 4, when the temple will reopen for rituals, was also made.These processions will be extended to the urban centres on November 5 and 6. A fund-raising will be conducted in Alappuzha and Pathanamthitta from November 1 to 4.The temple will reopen for the annual Mandalapuja-Makaravilakku festival on November 16, and go on till December 27, attracting crores of pilgrims. Kerala Published on COMMENT November 01, 2018 religion and belief courts and legal SHARE SHARE EMAILlast_img read more

In discussion on agri budget oppn accuses govt of neglecting farm sector

first_imgNEW DELHI: In a tersely-worded take down of the government in Lok Sabha on Tuesday, Congress MP Uttam Kumar Reddy pointed to the increasing number of farmer suicides and the ‘worsening’ agrarian situation in the country. Amid the growing opposition chorus asking the government to ensure adequate water, quality seeds and remunerative prices for farm produce, Reddy said the government’s flagship PM Fasal Bima Yojana had proven inadequate not only in providing cover to the total cropped area, but also in compensating farmers for their crop losses. Claims of farmers are not being attended to, he said, adding that insurance companies, instead of farmers, were profiting from PM Fasal Bima Yojana. Initiating a debate on Demand for Grants for Department of Agriculture and Farmers’ Welfare, Reddy alleged the government’s efforts in the agriculture sector were inadequate and claimed nearly 12,000 peasants commit suicide every year, but that the National Crime records Bureau had stopped releasing the data on farmer suicides since 2017. Citing an example of cotton, he also said farmers are getting one fourth of the cost. Agriculture minister Narendra Singh Tomar will respond to once the discussion on demand for grants on agriculture and farmer welfare is completed tomorrow. Among other MPs who spoke, DMK’s SS Palanimanickam said the farm sector was lagging behind all other professions in the country. He also suggested that if the goverenment wants to double farmers income they need to give special importance to sectors like dairy, poultry and fishery. BJP’s Ramapati Ram Tripathi, however, argued that the main focus of the Union Budget was village people and farmers. He also asserted that the Budget would help double farmer incomes. While BJP’s Ram Shankar Katheria stressed that farmers were happy and better cared for than by the Congress government, TMC MP Pratima Mondal accused the government of making farmers suffering because of the lack of emphasis on the agriculture sector. JDU MP Kaushlendra Kumar requested the government to focus on Bihar and Assam, both reeling under severe flood situation. Download The Times of India News App for Latest India News.XStart your day smart with stories curated specially for youlast_img read more

Floods affect 8 lakh in Assam 10 dead across Northeast as rains

first_img Next India Today Web Desk New DelhiJuly 12, 2019UPDATED: July 12, 2019 23:28 IST An village in Kamrup district of Assam on July 12. (Photo: IANS)Heavy rain and floods have thrown life out of gear in the entire eastern region with over eight lakh people being affected by the overflowing Brahmaputra in Assam. Non-stop rain in north Bengal and Sikkim has triggered several landslides, throwing normal life out of gear.Low-lying areas in north Bengal and Sikkim are also staring at a flood-like situation with the incessant rainfall while in Assam at least 6 people have been killed so far. A total of 10 people have died across three states of Assam, Arunachal Pradesh and Mizoram. Some are feared dead in Bengal.Here are the top 10 developments:1. Road connectivity between north Bengal and Sikkim has been completely disrupted by the continuous rainfall. Rail connectivity has also been disrupted in the Dooars region. Several tourists are struck on the road while two tourist vehicle were drawn into the Teesta River and bodies are yet to recovered due to the rising water levels in Teesta.2. Road connectivity between Siliguri and Sikkim has been shut. Heavy rain is expected till July 14.3. Over eight lakh people have been affected by the flood situation in Assam with more than half of the districts in the Northeastern state submerged under water.4. Barpeta in Assam is the worst hit district with over 85,000 people reeling under the impact of the floods. Six people have lost their lives in Assam so far.5. Animals are fleeing the Kaziranga National Park, the famed habitat of the Great Indian Rhino and a World Heritage site. Authorities have set up road barricades on the national highway passing through the park to limit speeding vehicles.6. The Assam disaster relief force has said nearly 800 villages in 41 revenue circles are under water and about2,000 marooned people have been put up in 53 relief camps and relief distribution centres set up by the district administrations.7. In Arunachal Pradesh, 2 girls were buried in their sleep and three others were injured after a landslide caused a boundary wall to collapse on the hostel building of a school in Tawang district.8. Arunachal capital Itanagar has been witnessing landslips, mudslides and road blockades due to heavy rainfall for several days and the district administration has ordered closure of all schools in Itanagar till Sunday.9. In Mizoram, 2 men have drowned and 390 houses submerged in floods triggered by incessant rain across the state. Disaster management and rehabilitation officials said landslides made many places inaccessible.10. The Itanagar-Naharlagun stretch of NH-415, which is being upgraded to a four-lane highway, is the worst hit by the monsoon fury.(With PTI inputs)Also Read | Incessant rains trigger landslides, bring life to a standstill in Arunachal PradeshAlso Watch | In Depth: Decoding the link between floods and droughtsFor the latest World Cup news, live scores and fixtures for World Cup 2019, log on to indiatoday.in/sports. Like us on Facebook or follow us on Twitter for World Cup news, scores and updates.Get real-time alerts and all the news on your phone with the all-new India Today app. Download from Post your comment Do You Like This Story? Awesome! Now share the story Too bad. Tell us what you didn’t like in the comments Posted bySanchari Chatterjee Floods affect 8 lakh in Assam, 10 dead across Northeast as rains lash region | 10 pointsHeavy rainfall and floods have affected the entire Eastern and Northeastern India. Over eight lakh people have been affected in Assam while the rain has disrupted life in north Bengal, Sikkim and other states.advertisementlast_img read more

20 Years of Kargil A ground report from Tololing in Drass

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