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An international team effort by scientists from Cornell University, USA, and Zhejiang University, China, has uncovered details of a symbiotic relationship between bacteria and Bemisia tabaci – a whitefly pest that transmits a number of viruses that can ruin crops. The study found that Hamiltonella defensa bacteria use the flies to replicate, passing from mother insect to offspring through their eggs. Meanwhile, whiteflies rely on the bacteria to provide essential amino acids that are missing from their food source. When the bugs were treated with antibiotics that kill H. defensa, the flies could no longer grow and reproduce. Since whiteflies are one of the biggest problems in crop agriculture worldwide, these findings shine some light on how we could combat them in the future.

A group of benign bacteria called Wolbachia is able to stop the Aedes aegypti mosquito from transmitting Zika virus, suggest scientists at the University of Wisconsin-Madison, USA, and Monash University, Australia. Previous studies by the same research team found that A. aegypti mosquitoes that carried Wolbachia were unable to spread dengue virus, which can cause serious human disease. Since Zika virus is closely related dengue, they wondered if the same thing applied. In lab tests, the scientists noticed that Wolbachia-carrying mosquitoes were less likely to become infected with Zika virus, and the few that did could not pass the virus on to people. These results could pave the way for new methods of controlling the spread of mosquitos and Zika virus.

A study led by scientists at Emory University School of Medicine, USA, suggests that the antibodies produced by humans when fighting off a dengue virus infection may actually make it easier for the related Zika virus to infect human cells. There are four strains of dengue virus and antibodies produced against one does not protect against the others. While these antibodies still attach to other dengue strains, they are unable to neutralise these viruses. The researchers found that the dengue antibodies also attach to Zika virus, but are again unable to neutralise, allowing the virus to spread. However, there is hope; the study helped identify antibodies that can neutralise Zika and these could help with designing future treatments.

With so many people using public transport, you may expect a train carriage to contain more disease-causing microbes than most other places. However, new research by scientists at Harvard T.H. Chan School of Public Health, USA, now reveals that there are fewer antibiotic-resistant microbes on Boston’s subway system than in the human gut. After swabbing seats, hanging straps, ticket machines and more, across three different rail lines, the researchers found 46 antibiotic-resistant genes, compared to the 1,000 or so found in our guts. The team hope that the results of the study could provide an early warning system for potential outbreaks.

New research from the University of Nevada, Reno, USA, may have a solution to decreasing the amount of Salmonella on fresh meat products – by using a type of virus called a bacteriophage that targets and kills specific bacteria. In lab tests, the scientists treated different kinds of Salmonella-contaminated minced meat with the Myoviridae virus and found it killed off up to 90% of the bacteria. The findings could lead to increased food safety in the meat industry.

A team of scientists from the University of Wisconsin-Madison, USA, has discovered an arms race happening in soil, between plant roots and plant pathogens. Ralstonia solanacearum, a soil bacterium that causes disease in many crops, likes to attack plants through any wounds or natural openings in their roots. However, some plants are fighting back, by secreting a sticky substance that traps and kills around a quarter of the bacteria. Further tests revealed that the plants do not release their sticky traps when exposed to harmless bacteria, suggesting that it is specifically a defensive mechanism against invading pathogens.

A team of researchers from the Max Planck Institute for Marine Microbiology, Germany, and the University of Calgary, Canada, have found that a newly-discovered protist from the mysterious Breviatea class, which they named Lenisia limosa, has partnered up with bacteria from the Arcobacter genus to improve both of their metabolisms. This teamwork could be considered bizarre, as bacteria are often protists’ prey. The study showed that L. limosa only produces certain enzymes that speed up its metabolism in the presence of Arcobacter. The bacteria in turn benefits from this relationship as the protist’s improved metabolism means it releases more hydrogen, which the Arcobacter then uses to produce more energy for itself.

Some bacteria, like Yersinia pseudotuberculosis, are able to identify when they are inside a warm-blooded host, but it had been difficult to study the tools they use to accomplish this until now. Researchers at Ruhr-Universität Bochum, Germany, have used a new technique to observe the RNA thermometer Y. pseudotuberculosis uses to find out about their host’s body temperature. Once at an optimal temperature, the bacterium immediately activates specific genes, such as those that protect it from its host’s immune system. These results could help towards finding ways to interfere with certain pathogens’ infection processes.

Scientists at the University of California, Davis, USA, believe that the different microbes found in must – the name that unfermented grape juice is known at in the wine-making process – may have a hand in shaping the final taste. The researchers identified different bacteria and fungi in samples of must and compared them to what could be found in the finished products. The study showed that the levels of specific metabolites – chemical compounds that affect the flavour and texture – in the wine corresponded with the microbes that were present during fermentation. This means that winemakers could potentially predict, and perhaps even affect, what their products will taste like based on the micro-organisms present at the very beginning of the process. However, the team warn that it is unlikely to be able to completely engineer an exact taste, due to the wide variety of other environmental factors.

In the wild, there are many more female green lacewings – a type of insect – than males, but it wasn’t really known why until now. Researchers at Chiba University, Japan, studied the bugs and discovered that a bacterium was to blame for this dramatic difference. The team treated some groups of green lacewings with antibiotics and these groups returned to a 1:1 ratio of female to male animals. Further investigation revealed that Spiroplasma, a species of bacteria related to known plant pathogens, was being passed down from mother to offspring, and killing off many of the male insects. The researchers suspect that this Spiroplasma may originally have also been a plant pathogen, but then jumped hosts to infect green lacewings.