C ytoplasmic incompatibility (CI) is the most widespread and, perhaps, the most prominent feature that Wolbachia endosymbionts impose on their hosts (1, 2). CI results in embryonic mortality (EM) in matings between insects of the same species with different Wolbachia infection status (3, 4). It can be either unidirectional or bidirectional. Unidirectional CI is typically expressed when an infected male mates with an uninfected female. The reciprocal mating is fully compatible, as are matings between infected individuals. Bidirectional CI usually occurs in matings between infected individuals harboring different strains of Wolbachia. Although the mechanism of CI has not yet been elucidated on the molecular level, several lines of evidence suggest that Wolbachia somehow modifies the paternal chromosomes during spermatogenesis (mature sperm does not contain the bacteria). This modification influences their behavior during the first mitotic divisions and results in loss of mitotic synchrony (5, 6). Even before the etiological connection between Wolbachia and CI was revealed in mosquitoes (7), attempts were made to exploit CI as a method to suppress natural populations of arthropod pests in a way analogous to the sterile insect technique (S.I.T.) (8). These early attempts involved the mass production and release of incompatible male insects to control wild populations of disease vectors such as the mosquito Culex pipiens (9) and of agricultural pests such as the European cherry fruit fly, Rhagoletis cerasi (10) and, at a smaller scale, the almond moth Cadra (Ephestia) cautella (11).The Mediterranean fruit fly (medfly) Ceratitis capitata is a worldwide pest that infests Ͼ250 fruit varieties of economic importance (12). Extensive screenings of both laboratory and natural populations of medfly have shown that this insect pest is not infected with Wolbachia (13). However, at the time of this writing, ongoing experimental work suggests that some Brazilian natural populations of medfly may be infected with Wolbachia (D. Selivon, personal communication). To determine whether the medfly can support Wolbachia infections and express CI, we used conventional embryonic cytoplasmic injections (14-17) for transfer of natural bacterial symbionts from a related species, R. cerasi (Diptera, Tephritidae) (18), to an uninfected laboratory strain of medf ly C. capitata (Diptera, Tephritidae), the Benakeion strain.Previous studies have demonstrated high levels of incompatibility between natural populations of R. cerasi (10,19), the basis of which was recently shown to be Wolbachia (18). Populations of R. cerasi are either infected by a single Wolbachia variant, wCer1, or coinfected by two variants, wCer1 and wCer2. Incompatibility occurs between males from doubly infected populations and females from singly infected populations, suggesting the wCer2 infection as the cause of CI (18). Additionally, transfer of wCer2 in Drosophila simulans also resulted to the induction of CI (17). An additional, yet uncharacterized, Wolbachia strain (wCer...

Oil pollution has been a worldwide concern especially in environments where treatment is quite difficult to apply. Marine polluted sediments, in particular, constitute one of the most recalcitrant environments for bioremediation and are often the final repository of petroleum contaminants, as a result of runoff and deposition. Aerobic hydrocarbon degraders present in the sediments are tackling the pollution under oxygen-limited or oxygen-depleted conditions. Research has focused on new ways to enhance bioremediation under anoxic conditions, however aerobic bioremediation is faster, and hence more effort should be made to sustain oxygen concentration levels. In this review, the different bioremediation techniques used for the decontamination of marine sediments are briefly discussed, and focus is primarily given to the different oxygenation methods used for enhancing aerobic bioremediation and the aeration methods that are suitable for in situ application, as well as state of the art technologies that make in situ aeration an appealing approach. Based on the technologies analyzed, suggestions are made for sediment bioremediation techniques in different marine environments.

No abstract