Bacteriophages (phages) and other mobile genetic elements (MGEs) exert an immense selective pressure on     1    (bacterium), which in response have developed a broad arsenal of defence mechanisms.     2     these, CRISPR–Cas (clustered regularly interspaced short palindromic repeats–CRISPR-associated proteins) is a group of widespread RNA-guided adaptive immune systems that are classified into two broad classes, six types and numerous subtypes according to their genetic composition and interference mechanism1. The CRISPR–Cas immune response starts with the    3    (acquire) of short DNA fragments (protospacers) from invading MGEs. The protospacers are inserted as spacers between repeats in the CRISPR array to create a memory of the infection. Next, the CRISPR array is expressed    4     a long transcript that is processed into small, mature CRISPR RNAs (crRNAs), each    5    (carry) a spacer sequence flanked by part of the repeat. Finally, the interference complexes, composed     6     a crRNA and one (class 2) or more (class 1) Cas proteins, degrade the complementary nucleic-acid targets that are often found next to a short protospacer-adjacent motif (PAM). The specificity and programmability of the CRISPR–Cas machinery     7    (lead) to the development of various biotechnological applications in genome editing, molecular diagnostics and more.

In the evolutionary arms race with CRISPR–Cas, phages and other MGEs have evolved diverse strategies to block or circumvent immunity. One widespread evasion mechanism uses protein-    8    (base) CRISPR–Cas inhibitors called anti-CRISPRs (Acrs). So far, more than 100 Acr protein families have been identified    9     inhibit different stages of the CRISPR–Cas immune response, mainly by interacting directly with Cas proteins. For example, Acrs prevent crRNA loading, effector-complex formation, and target DNA binding and cleavage. Notably, the discovery of these natural ‘off switches’ has presented new opportunities    10    (control) the activity of CRISPR–Cas technologies.

2 . “Going wireless is the future for just about everything!” That is a quote from scientist Sreekanth Chalasani, and we can’t help but agree. Realizing this, a team of scientists has made a breakthrough toward wirelessly controlling human cells using sound, in a technique called “sonogenetics (声遗传学).” This concept may seem strange but let us explain.

Basically, the term “sonogenetics” means using ultrasound (超声波) to change the behavior of cells in a non-invasive manner. “We already know that ultrasound is safe, and that it can go through bone, muscle and other tissues, making it the ultimate tool for controlling cells deep in the body,” says Chalasani.

Low-frequency ultrasound waves can target a particular protein that is sensitive to the signal. This research, published in Nature Communications, focused on TRPA1. When this protein is stimulated through the ultrasound waves, it also stimulates the cells which carry it. What type of cell is being stimulated depends on the outcome. For example, a muscle cell may contract with stimulation, or a neuron (神经元) in the brain will fire. In this experiment, scientists genetically marked cells with an increased concentration of TRPA1, making them the key targets of the ultrasound waves.

Currently, treating conditions like Parkinson’s disease requires scientists to implant electrodes (电极) in the brain which stimulate certain disordered cells. Researchers hope that sonogenetics can one day replace these invasive treatments.

In the future, the team wants to adjust the placement and amount of TRPAI around the body using the gene treatment. Gene delivery techniques have already been shown to be successful in humans, such as in treating blindness. Therefore, it’s just a case of adjusting this theory to a different sound-based setting.

“Gene delivery techniques already exist for getting a new gene—such as TRPA1—into the human heart,” Chalasani says. “If we can then use an external ultrasound device to activate those cells, that could really change pacemakers.” There is still a while to go before this treatment can become a reality. The future for sonogenetics, though, looks bright.

3 . First woman is reported cured of HIV

A patient in the United States with the disease leukaemia(白血病)has become the first woman to be cured of HIV, the virus that causes AIDS. The patient received stem cells from a donor.     1    The donor was naturally resistant to HIV, researchers told reporters Tuesday.

The woman has been described as a 64-year-old woman of mixed race. Her case was presented at the Conference on Retroviruses and Opportunistic Infections in Denver, Colorado.

    2    The umbilical cord connects a pregnant mother to her fetus(胎儿). Use of umbilical blood is a somewhat new method. Doctors are considering making the treatment available to more people.

The woman had been receiving the umbilical cord blood to treat her leukaemia. Leukaemia is a cancer that starts in blood-forming cells in bones. Since receiving the treatment, the woman has been in remission.     3    She has not needed HIV treatments known as antiretroviral therapy.

The two earlier cases in which patients were cured happened in males who had received adult stem cells. Adult stem cells are often used in bone marrow transplants. “This is now the third report of a cure in this setting, and the first in a woman living with HIV, “said Sharon Lewin in a statement, who is soon to be the head of the International AIDS Society.

The woman’s case is part of a larger study led by Dr Yvonne Bryson of the University of California, Los Angeles, and Dr Deborah Persaud of Johns Hopkins University in Baltimore, Maryland.    4    The study aims to follow 25 people with HI who receive a transplant with stem cells taken from umbilical cord blood for the treatment of cancer and other serious conditions. The study suggests that an important part of the treatment’s success was using HIV-resistant cells.

5 . If you followed the 2016 Rio Olympic Games, you may have noticed that several athletes, including US swimmer Michael Phelps, had circular bruises on their bodies. These bruises were the results of “cupping therapy”, a traditional Chinese medical practice that has been around for more than 2,000 years.

Cupping therapy involves attaching circular cups to the skin using suction(吸力). The suction is created either by heating the cup inside or by using a handheld pump. This suction pulls the skin upward into the cup. Sometimes it can leave dark red bruises, other times there is no mark at all.

Many athletes say that they have benefited from the therapy. Phelps used the therapy in the fall of 2014 and has used it about twice a week since, reported ABC News. Another US swimmer, Dana Vollmer, also believes that “it really helps with blood flow, and helps pull swelling out of different areas.”

However, some have said that the supposed health effects result from people feeling that the treatment works, rather than any physical effects of the treatment.

To figure out whether cupping therapy has any physical effects, last year researchers from Germany carried out a test in which a sham(假装的) treatment was provided.

In the study, the same type of cups was used in the real treatment and the sham treatment. But in the sham treatment, the cups had a hole at the top so that they couldn’t create the proper suction.

The tested patients, who suffered from a disorder(疾病) that causes a lot of pain, were told that they would receive either a traditional cupping or “soft cupping”. But they were not informed that the so-called “soft cupping” was a sham treatment.

It turned out that most patients correctly guessed which kind of cupping they had received. In both groups, patients also experienced about the same reductions in pain. The results suggest the effects of cupping therapy might come fro factors that are not necessarily part of the treatment itself, the researchers told the Live Science website.

The question of whether cupping therapy works still needs to be answered. But because the treatment is relatively safe and it could be helpful for some people, “the therapy can be used as a part of a comprehensive treatment program involving other exercises, nutritional choices and lifestyle interventions(干预)”, Dr Brent Bauer, director of the US’ Mayo Clinic Complementary and Integrative Medicine Program, told Live Science.