Author: Luigi Guarino

Posted on

Fire and crop wild relatives

As wildfires rage across much of southern Europe, causing death and destruction, it’s sometimes difficult to remember — and perhaps insensitive to mention — that this is in fact a common occurrence, even necessary for the maintenance of vegetation and biodiversity in the Mediterranean.

In the Mediterranean, as in the mediterraneoids, fire occurs where vegetation is flammable. Combustibility is not a misfortune but an adaptation: plants that burn do so because they are fire-adapted. They make fire-promoting resins and other chemicals, or they have structural adaptations, such as producing a loose, airy litter of dead leaves and twigs which dries out and burns. Their ecology involves catching fire from time to time and burning up competitors.

Still, one wonders whether this might be too much of a “good” thing, and whether we’re heading for even more with climate change. What will this mean for particular species, for example crop wild relatives? Do we know how many are fire-adapted? And do we know even for those that are so adapted whether beyond a certain frequency or intensity fire becomes a threat rather than a necessity?

Posted on

A Svalbard for animals in the making?

I had somehow missed news earlier this year of a failed (just) attempt to clone the Pyrenean ibex. That’s an extinct subspecies of the Spanish ibex, Capra pyrenaica. I was belatedly alerted to it by a piece in LiveScience about “a new project to store tiny samples of tissue from endangered animals at New York’s natural history museum.”

With room for up to 1 million specimens, the AMNH’s frozen tissue lab currently stores frozen butterflies, frog toes, whale skin and alligator hides, among many other samples, in nitrogen-cooled vats. The collection is used today for conservation research — the genetic information gives clues to the breadth of the animals’ hunting grounds and breeding behaviors. In an agreement signed this month with the National Park Service, the museum will begin storing tissue samples of endangered animals living in the nation’s parks. The first samples — blood from a Channel Islands fox — should be delivered in August, museum officials said.

Maybe they should also include the caribou, “a species historically considered so numerous — and so distant from human activity — that most assumed it was beyond human ability to affect it.” But is perhaps in trouble now. Room for 1 million specimens might not be enough.

Posted on

Forays in fermentation

ResearchBlogging.org
There’s a couple of interesting articles about cereal fermentation in the latest Food Microbiology. Both basically say that fermentation is a useful way of getting more nutrition out of your staples. Rob Nout 1 describes how various traditional fermented dishes are made in Africa and Asia, ranging from kenkey in Ghana to idli in Sri Lanka. The former is made from maize, the latter from rice. Here’s the part of the paper’s Table 1 which lists fermented foods made from maize and sorghum (pearl millet, finger millet and rice are also considered):

table

It can get complicated. Here’s how they make jnard in India (I’ve removed the references to ease the flow), for example:

Jnard is an opaque beer made from finger millet (Eleusine coracana). Although – judging by its description – it would seem similar to Tchoukoutou, its mode of processing is fundamentally different. Whereas Tchoukoutou is brewed from sorghum malt, Jnard is saccharified by the action of an indigenous amylolytic starter (Murcha) on previously soaked and cooked fingermillet paste. Murcha is a rice-based dried tablet containing a mixed microflora of filamentous fungi, yeasts and lactic acid bacteria, and differs from koji which is a concentrate of fungal conidia of e.g. Aspergillus oryzae, used in the preparation of soya sauce and similar products. The process of preparing Jnard includes an overnight soak of finger millet seeds to soften them, grinding to obtain a crushed mass which is cooked and cooled to about 30ºC. Then, pulverized Murcha is sprinkled in the cooked mass and during a 1-3 day incubation, saccharification, lactic fermentation and alcoholic fermentation take place simultaneously. Functional microorganisms of Murcha and similar Asian amylolytic starters are filamentous fungi (Amylomyces rouxii, Rhizopus oryzae, etc.) which produce a range of enzymes including glucoamylase that degrades starch directly into glucose; yeasts (Endomycopsis fibuligera, Saccharomyces cerevisiae, etc.) which ferment part of the glucose produced; and lactic acid bacteria (Enterococcus faecalis, Pediococcus pentosaceus and others) growing together with the yeasts. LAB are able to co-exist with yeasts in a protocooperative manner.

Continue reading “Forays in fermentation”