Thursday, November 26, 2015

Can we GMO our way out of the mosquito mess?

There has been a great deal of controversy about terminator gene technology in plants, but similar genetic processing in insects, not so much.

Perhaps it's just because we don't like a lot of insects, but also because insects are particularly effective ecosystem invaders, plant pests and disease vectors.

Think Vespula vulgaris, the meat-eating alien wasp that is wiping out native pollinators on Haleakala. Think centipedes, also not native. Think the more than 40 species of ants, all of them imports. There are several introduced species of fruit fly now, which fill fruits with squirming maggots. Think ground termites, B52 cockroaches and, of course, mosquitoes.

No mosquitoes existed in the Islands until they arrived via a contaminated water cask on a whaler in the 1800s. Now there are multiple species. They suck your blood, and depending on species, they spread diseases that are killing off native forest birds. And then, of course, there is our latest scourge, dengue fever.

In a sense, technology caused this problem. Mainly transportation technology, which gets things--all kinds of things--to the Islands quickly.

Can technology fix it? Maybe, and there are lots of people working on it.

"Terminator" technology in plants has been developed but never used in production agriculture. It renders seeds sterile at harvest. That means you can't replant your seeds, but also means the genes can't spread.

Some folks consider it a spooky technology for crop plants, but what about pest insect control?

A British firm, Oxitec, has developed a bioengineered Mediterranean fruit fly that will mate with wild flies and pass on a trait that prevents female offspring from maturing, and thus prevents them from reproducing. Very specific, so unlike insecticides, no other species--like pollinators
and attractive butterflies, are impacted. It's about to be tested indoors in Australia.

Oxitec has also developed a response to the mosquitoes that carry dengue fever. It is a slightly
different technology, creating sterile males, which mate with females, but no viable eggs are produced.

Other researchers are working on technology that causes mosquitoes to only produce male offspring.

U.S. scientists in California have produced a version of a malaria mosquito that can't become infected with malaria--you've still got the mosquito, but it can't make you sick.

Genetic engineering is hardly the only tool being developed to control insect pests. Alternatives include sterilizing radiation and chemical technologies.

There are questions of efficiency and morality in all this.

If you take the approach of stopping a bug from passing on a specific disease, then you need a technology for dengue, and one for avian pox, and one for human malaria, and one for avian malaria, and one for chikungunya. There are issues. Pox and dengue are viruses. Malaria involves a parasite.

The solutions need to be different.

And there is the public outcry about genetic modification of anything. Tens of thousands of people have signed petitions to stop the release of genetically modified mosquitoes that would help stop disease.

And you would still have the mosquitoes.

The technology can also be used to greatly reduce numbers or even eradicate a species,of mosquito. In some parts of the world that is opposed on moral or environmental grounds since mosquitoes are a part of the natural ecosystem.

In Hawai'i, they are alien invaders, deeply disruptive to our natural environment, both annoying and sometimes dangerous around our communities, and entirely unwanted except by a few creatures that feed on them. Different story,, although the issue of releasing genetically modified organisms is still there.

The technology to address the issue will come in several forms, and each alternative will have impacts. Doing nothing may have even greater impacts.

{c} Jan TenBruggencate 2015

Sunday, November 22, 2015

Drought-resistant pineapple has clues for drought resistance in other crops

Drought is responsible for most of the world’s crop losses, and researchers say that new work on drought-resistant pineapple is providing clues.

“Understanding the mechanisms that plants have evolved to survive water stress is vital for engineering drought tolerance in crops,” write the authors of a new study  in the journal Nature Genetics.

(Image: Pineapple [Ananas comosus {L.} Merr.]. Source: University of Hawai`i.)

Pineapple, the world’s second most important tropical fruit after bananas, is a member of the bromeliad family—the only bromeliad to produce a commercially important fruit. The bromeliads and the grasses are descended from a common ancestor.

An international team of researchers, including two from the University of Hawai`i at Mānoa, sequenced the pineapple genome. The two are Nancy Jung Chen and Robert Paull, with the university’s Department of Tropical Plant and Soil Sciences in the College of Tropical Agriculture and Human Resources. The project’s leader, Ray Ming, is a former University of Hawai`i researcher who is now with the University of Illinois.

They sequenced wild pineapple as well as two commercial species—an old high acid variety used in canned pineapple and a newer low-acid variety used primarily for fresh fruit sales. Pineapple has the scientific name Ananas comosus.

The researchers are looking at flower metabolism, sugar production and other features, but an important research objective is understanding pineapple’s drought tolerance, according to the University of Hawai`i’s press release on the project. 

“The plant possesses an alternate photosynthetic pathway that concentrates carbon dioxide during the night when water loss is less. This reduced water loss leads to high water-use efficiency,” the release says.

The name scientists use for this process is crassulacean acid metabolism or CAM.

Pineapples convert carbon-dioxide into malic acid at night , and then use it in the daytime while they keep their stomata closed to preserve moisture.

Here’s how the scientists say that: “CAM plants can keep their stomata closed during the daytime while the stored malic acid is decarboxylated and the carbon dioxide released is refixed through the Calvin-Benson cycle, greatly reducing water loss through evapotranspiration.”

Stomata are plant pores from which gases, including moisture, can be exchanged. Closing them in daylight can prevent moisture loss during hot, dry, sunny periods. Malic acid is an organic acid found in all fruits,.

The authors suggest that the drought resistance of pineapple could be conveyed via genetic engineering into other crops: “This work provides the first detailed analysis of the expression and regulation patterns of genes associated with CAM and could ultimately be used to engineer better (water-use efficiency) and drought tolerance in crop plants.”

Drought tolerance has been a key goal of crop plant breeding and genetic engineering worldwide.

Pineapple is originally a Central American plant, first reported by Europeans on Christopher Columbus' voyage. It once was one of Hawai`i's economic mainstays, second to sugar.

"Today, pineapple is cultivated on 1.02 million hectares of land in over 80 countries worldwide, and 24.8 million metric tonnes of fruit are produced annually with a gross production value approaching $9 billion. Pineapple has outstanding nutritional and medicinal properties," the paper's authors write.

© Jan TenBruggencate 2015

Saturday, November 21, 2015

University of Hawai`i astronomers detect asteroid collision beyond Mars.

There’s a lot of empty space in space, but there’s a fair amount of stuff zipping around in it.

Collisions are rare, but inevitably, they happen—it accounts for craters on the Moon, and some of the features on the Earth.

(Image: Main-belt asteroid (493) Griseldis with temporary tail. Credit: David Tholen, Scott Sheppard of Carnegie Institution, Chad Trujillo of Gemini Observatory.)

And recently, a University of Hawai`i telescope helped spot one out farther from the sun in our own solar system.
Out in the Asteroid Belt, between Mars and Jupiter, on March 17, astronomers using the 8-meter Subaru Telescope on Mauna Kea noticed that an asteroid named Griseldis had suddenly grown a tail.

Several days later, the 6.5-meter Magellan telescope in Chile showed the tail was still there, but smaller.

Images taken by the University of Hawai`i’s 2.2-meter telescope on Mauna Kea showed that the tail did not exist back in 2010 or 2012, and that it had disappeared by March 24. Magellan on April 18 and May 21 also showed the tail was gone.

University of Hawai`i astronomer David Tholen reported the results at a Nov. 12 session of the Division for Planetary Sciences of the American Astronomical Society.

The sudden appearance and quick disappearance of a tail suggests something crashed into the asteroid, caused a plume of dust, which then dissipated, Tholen said.

“The observations are consistent with the occurrence of an impact event on this asteroid,” the research group working on the project said.

The University of Hawai`i press release on the event
is here. 

© Jan TenBruggencate 2015

Dengue: You don't know how big a threat it is. It's big.

Not too worried about dengue fever? 

You should be. It is the leading cause of illness and death in the tropics and subtropics. It's a miserable disease to have. 

The U.S. Centers for Disease Control and Prevention (CDC) say 400 million people annually are infected.

And there’s a lot you likely didn’t know about this mosquito-borne disease, which has showed up and been defeated several times in the Hawaiian Isands, but now appears widespread now on the Big Island. 

One feature of the disease is that there are four different related viruses that cause dengue. If you get one, you’re protected from getting that one again, but after a few months you can get any of the other three. Most parts of the world have all four types.

There is some evidence that if you get a second type after a first infection, the symptoms can be significantly more severe.

Dengue is pretty much everywhere within a thousand miles or so of the equator—Hawai`i has been one of the outliers in not having it.

There is no vaccine for it so far, although there's a lot of work being done toward a vaccine. Your best hope of not getting it is not getting bitten. 

It is possible to have the infection and not have symptoms—but you’ll still be able to pass the disease to others via mosquito bites.

Dengue is in a group of viruses called Flaviviruses. Yellow fever and West Nile are also in that group. It causes illness that outwardy mimics a lot of other disease, even flu. It can be very similar in outward appearance to another tropical disease called chikungunya. Says the CDC: “Chikungunya and dengue are both acute febrile illnesses characterized by fever, myalgia, and lethargy. Some patients may also have … rash, nausea, vomiting, and headache.” 

Fortunately, we don’t have chikungunya in the Islands. On the other hand, dengue is worse: “Chikungunya is rarely fatal. In contrast, early identification and proper clinical management for hospitalized dengue cases can reduce the case-fatality rate from 10% to less than 0.1%. Therefore, patients suspected of having dengue or chikungunya should be managed as having dengue until dengue can be ruled out.”

Dengue can be transmitted blood to blood, but the main reservoir for infection is mosquitoes. Two mosquito varieties can carry dengue, Aedes aegypti and Aedes albopictus. We have both of them in Hawai`i. Albopictus, the Asian tiger mosquito, is a daytime biter. Aegypti is a daytime biter that’s most active a couple of hours after dawn and before sunset. Aegypti is the one you’re more likely to find inside your house.

The virus is creepily robust. Most get it from the mosquitoes, but folks working in laboratories have been infected: “The virus is stable in dried blood for up to 9 weeks at room temperature,” says the Public Health Agency of Canada. Dengue isn’t in Canada, but visitors to the tropics can bring it home.

You get sick 4 days to a week after being bitten, and you can stay sick 3 to 10 days. In some people, it can progress to more serious diseases called dengue hemorrhagic fever and dengue shock syndrome, which can be fatal. These diseases are more common in young children than adults.

Folks who have traveled in the tropics often have experienced airline crews spraying insecticide up and down the aisles. Often, that’s for dengue, which can be so painful it’s called “breakbone fever.”

You avoid getting dengue by avoiding getting stung by infected mosquitoes. Recommendations are to stay out of areas with lots of mosquitoes, and to wear protective clothing and insect repellent if you must be there. Also, reduce mosquito numbers in your environment by emptying standing water where they breed in pots, plants, and other locations. 

Longer term, to stop the cycle of infection, public health authorities need to break the cycle of humans passing the disease to mosquitoes and mosquitoes passing it to humans.  If new infections can be stopped for several weeks, the cohort of infected mosquitoes can die off, and the reservoir of infectivity is shut down. A mosquito, once it picks up the virus, can pass it on for its lifetime, but does not pass it on to its young.

Once again, the key symptoms of dengue, according to CDC, are a lot of pain—headache, pain behind the eyes, joint pain, muscle pain, bone pain—and also rash, mild bleeding from the nose or gums, and bruising or red and purple spots on the skin. Lab tests will show low white blood cell counts.

Victims should seek immediate medical attention, CDC says, if the symptoms move to severe abdominal pain or persistent vomiting; red spots or patches on the skin; bleeding from nose or gums; vomiting blood; black, tarry stools; drowsiness or irritability; pale, cold, or clammy skin; or difficulty breathing.

The Hawaii State Department of Health fact sheet on dengue. 
The Centers for Disease Control and Prevention web pages
World Health Organization treatment guidelines

© Jan TenBruggencate 2015

Tuesday, November 17, 2015

Natural pesticides from a common weed launched Kaua`i's pesticide furor

(Note: A version of this article appeared Nov. 17, 2015, in Honolulu Civil Beat.) 

The plant blamed for much of Kaua`i’s pesticide furor is a medicinal, edible shrub with a truly awful smell. 

It flowered again recently, sending across the West Kauai landscape a rank stench which, in susceptible folks, can cause teary eyes, headaches and nausea.

West Kauai sugar plantation workers call it spiderflower, but it is more often known as stinkweed; its scientific name is Cleome gynandra.

In November 2006, students and staff at Waimea Canyon Middle School complained of a bad smell that made them nauseous and left them with throat irritation, watery eyes and dizziness. Many attributed it to agricultural spraying on a field next to the school. 

It flowered again recently—the same time of the year as the initial 2006 report—and on West Kauai, people were once again complaining about the stench.

(Image: A ratty-looking sample of stinkweed, Cleome gynandra, in a field west of Kekaha on Kaua`i. Credit: Jan TenBruggencate. )

When I heard of the latest stinkweed outbreak in the second week of November 2015, I went to West Kauai and collected samples (in sealed plastic bags) in Waimea, Kekaha and Mana—some on my own and some during a driving tour with Allan Smith and Robin Robinson of Syngenta, a seed company that leases extensive acreage in the area.

(Image: A healthier looking stinkweed photo specimen.  Credit: Forest and Kim Starr.)

One of the things that struck me about the plant is that its smell is so variable. Some specimens smelled not at all. Others were very strong—enough to make you gag. Some had a very intense chemical smell, others a smell similar to the popular local vegetable bittermelon (Momordica charantia). When it was blooming in past years, Robinson said, sugar plantations would sometimes get calls about a petroleum odor, with callers suggesting there must be a fuel spill nearby. 

“I can smell the sulfur in it,” said one person I asked to smell the plant sample in one plastic bag. “But this sample over here smells almost good.”

This variability is confirmed on the website for Plant Resources of Tropical Africa, which says people who grow it commercially have difficulty getting consistent results, because of variability in many features of the plant. 

The variability also helps explain why some of the affected individuals at Waimea Canyon Middle School, who said they were familiar with stinkweed elsewhere, insisted that it’s not what they smelled at Waimea.

The Hawai`i Center for Food Safety, in its Pesticides in Paradise report, insists that pesticides and not any plant are to blame: "A teacher...rejected the explanation given by Hawai`i officials and Syngenta that 'stinkweed' was he culprit, saying she was familiar with stinkweed's odor and that was not the cause."
The flowering alone can release a strong odor, but if the plant is rubbed or crushed, or if a field of stinkweed is plowed, the stink can be overpowering. One of the reported incidents at Waimea Canyon Middle School occurred while the plant was flowering, another while the stinkweed-infested field was being tilled, Robinson said.

Waimea Canyon Middle School was impacted several times from 2006 to 2008 with the odor that apparently blew in from a neighboring field. Many of the teachers and parents of impacted students blamed agricultural spraying on nearby fields. 

The much-criticized CFS report argues that "Communities in Hawai`i are rightly concerned about pesticide drift that occur from open-air GE seed corn operations. Teachers and schoolchildren in Waimea on Kaua`i became sick on at least three separate occasions following chemical applications to a nerby seed corn plot...

"In a 2008 episode, 60 children and at least two teachers experienced headaches, dizziness, nausea and/or vomiting; 10 or more children were treated at an emergency room, several were put on a nebulizer to relieve respiratory distress and one as given an anti-vomiting medication intravenously."

The state commissioned a study by Qing X. Li, Jun Wang and Robert Boesch, of the University of Hawai`i’s Department of Molecular Biosciences and Bioengineering. Their findings, which are rejected by some of the affected school folks, concluded that spiderflower/stinkweed is a powerful chemical factory.

“A closed chamber laboratory air emission study identified 29 chemicals (some with insecticidal activities) produced by stinkweed,” they said in their report. When they compared that with air samples in the field, they found all 29 chemicals in the air. When they tested the air at the school—indoors and outdoors—they found about half of those chemicals.

The chemical that the scientists felt was likely most at fault is a natural, plant-based compound called methyl isothiocyanate (MITC), an organosulfur compound. Their studies showed it is significantly higher in concentration in flowers and seed pods than leaves and stems of the stinkweed.

“MITC is a highly foul-smelling, noxious chemical at high concentrations, and is cited as a potent lachrymator (eye irritant) and nose and throat irritant. Besides MITC, other stinkweed derived compounds found during this study are also known potential irritants,” they wrote.

The studies also found residues of five known pesticides. When they did the air quality testing, they found that “Concentrations of the pesticides and MITC were well below health concern exposure limits or applicable screening levels.”

The plant has been in the Hawaiian Islands for more than 150 years, having first been observed in 1857. It is on all the main islands, sometimes known as honohina, `ili`ohu, wild spiderflower or spiderwisp. It is native to central America, from Texas south to Argentina, according to the Manual of the Flowering Plants of Hawai`i.

It has spread around the world, a weed in some areas and a cultivated plant in others. The leaves are eaten in Africa and parts of Asia, although it must be cooked. One Thailand website warns that cooking, drying or fermentation reduces the levels of hydrocyanic acid, which it says is toxic to central nervous system. 

The plant is attractive to some insects; repellent to others. In some areas it is used as a mosquito and tick repellent, but when I viewed it on West Kaua`i, many species were severely infested with
It seems to do best after a rain in the drier parts of the Islands. It is recognized by a 5-part leaf (sometimes 3 or 7), long narrow seed pod, and small white flowers that have long spidery parts extending beyond the petals.

It is in the Capparaceae family. A native Hawaiian plant in the same family is maiapilo or pua pilo.

© Jan TenBruggencate 2015