Volume 10 [2008]

Phytoremediation is a low cost alternative solution to soil contamination compared with
traditional removal and/or disposal techniques. One of the phytoremediation technologies is
the phytovolatilization, whereby the contaminant is not primarily accumulated in above-ground
tissues, but is instead transformed by the plant into the atmosphere. The detoxification of
highly toxic organmercurial compounds and subsequent volatilization of elemental mercury is
a unique example for the successful phytoremediation based on genetic engineering
approach. For mercury removal techniques we constructed a dicistronic construct containing
the bacterial mercury detoxification genes merA and merB under the control of the
Arabidopsis Actin2 promoter and terminator. The resulted construct was introduced to
Agrobacterium competent cells using heat shock transformation method. In the mean time,
we germinated tobacco (Nicotiana tabacum var. Gold leaf) seeds on MS media and infected
leaf discs of 6-8 weeks tobacco seedlings with Agrobacterium containing Ti plasmid harboring
merA/merB dicistronic construct. The results showed that about 90% of tobacco seedlings
were carrying the mer genes. Tobacco seeds were collected from wild type and transgenic
lines and tested for mercury resistance. The results showed that transgenic plants are
resistant to both Phenyl Mercuric Acetate (PMA) and HgCl2. The root length and dry weight of
wild and transgenic seedlings growing on both media amended with mercury compounds and
media without mercury (control) were scored. The results showed that the root lengths and
dry weight of the transgenic lines are significantly higher by 60 and 17-folds, respectively,
compared to wild type. The results showed clear evidence that the transgenic plants are
resistant to both organic and inorganic mercury compounds and can be used to clean up
mercury contaminated sites.

In the present study an assessment of the influence of the ambient air pollution on the
incidence of the Childhood Asthma Admissions (CAA) is attempted by using cross spectrum
analysis. The medical data concern the hospital registries of the three main Children’s
Hospitals of Athens for the 14-year period, 1987-2000. The air pollution data used in this
study were mean monthly concentrations of CO, Black Smoke (BS), NOx, SO2, and O3,
averaged over all the available stations, for each air pollutant, in the network of the Greek
Ministry of the Environment, Physical Planning and Public Works (GMEPPPW) for the
aforementioned 14-year period. The performed analysis revealed that a pronounced seasonal
variation of asthma exacerbation among Athenian children does exist, rising during the cold
damp period in pre-schoolers and peaking around May in the schoolchildren. We found that
asthma admissions are associated with ambient air pollution at different frequencies. Asthma
exacerbation among the first age group (0-4 years) is strongly depended on winter air
pollution whereas older children (5-14 years) appear to be more vulnerable to the exposure of
primary air pollutants mainly during late spring. Our findings strengthen the aspect that
weather conditions such as sea breeze, mainly happen at the late spring or early summer in
association with air pollution episodes could affect childhood asthma exacerbation.