Jumping Ship: A Stepping Stone Event Mediating Transfer of a Non-indigenous Species Via a Potentially Unsuitable Environment

The smooth shelled blue mussel, Mytilus galloprovincialis Lmk (Bivalvia: Mollusca) arrived in Pearl Harbor, Oahu, Hawai'i on 22 June 1998 as a member of the fouling community of the USS Missouri, and mussel spawning activity was observed within 2h of the vessel's arrival. Small mussels (<10mm shell length, approximately 6 weeks post-metamorphosis) were collected on 30 September 1998 from a submarine ballast tank in Pearl Harbor, indicating that a successful recruitment event had taken place very soon after the first arrival of the species at this location. We suggest that even if M. galloprovincialis is not able to establish permanently within Pearl Harbor, the fact that it has been able to successfully spawn and recruit to another shipping vector within the Harbor indicates that a stepping stone model of range expansion from temperate to temperate region via an intermediary subtropical environment is quite feasible for this species. Data from worldwide distributions of mussels of the family Mytilidae indicate that preferred habitats are eutrophic continental shelf regions, which suggests that successful establishment within Pearl Harbor is possible. However, oceanic coral-reef environments are not preferred habitat types, suggesting that M. galloprovincialis is not likely to become widely distributed in the Hawaiian Islands.     

<Emphasis Type="Italic">Chlamydia pneumoniae</Emphasis> infected macrophages exhibit enhanced plasma membrane fluidity and show increased adherence to endothelial cells

Chlamydia pneumoniae, an intracellular prokaryote, is known to have requirement for some lipids which it is incapable of synthesizing, and these lipids have important fluidizing roles in plasma membrane. We decided to examine if the trafficking of these lipids to C. pneumoniae alters the physicochemical properties of macrophage plasma membrane, affects the expression of genes and proteins of enzymes associated with metabolism of some of these lipids and assess if Ca²⁺ signaling usually induced in macrophages infected with C. pneumoniae modulates the genes of these selected enzymes. Chlamydia pneumoniae induced the depletion of macrophage membrane cholesterol, phosphatidylinositol and cardiolipin but caused an increase in phosphotidylcholine resulting in a relative increase in total phospholipids. There was increased membrane fluidity, enhanced macrophage fragility and heightened adherence of macrophages to endothelial cells despite the application of inhibitor of adhesion molecules. Also, there was impairment of macrophage 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase gene and protein expression independent of Ca²⁺ signaling, while phospholipase C gene and protein were up-regulated in a manner minimally dependent on Ca²⁺ signaling. The implications of these findings are that macrophages infected with C. pneumoniae have altered membrane physicochemical characteristics which may render them atherogenic. (Mol Cell Biochem 269: 69–84, 2005)     

Disabled-2 mediates c-Fos suppression and the cell growth regulatory activity of retinoic acid in embryonic carcinoma cells

F9 embryonic stem cell-like teratocarcinoma cells are widely used to study early embryonic development and cell differentiation. The cells can be induced by retinoic acid to undergo endodermal differentiation. The retinoic acid-induced differentiation accompanies cell growth suppression, and thus, F9 cells are also often used as a model for analysis of retinoic acid biological activity. We have recently shown that MAPK activation and c-Fos expression are uncoupled in F9 cells upon retinoic acid-induced endodermal differentiation. The expression of the candidate tumor suppressor Disabled-2 is induced and correlates with cell growth suppression in F9 cells. We were not able to establish stable Disabled-2 expression by cDNA transfection in F9 cells without induction of spontaneous cell differentiation. Transient transfection of Dab2 by adenoviral vector nevertheless suppresses Elk-1 phosphorylation, c-Fos expression, and cell growth. In PA-1, another teratocarcinoma cell line of human origin that has no or very low levels of Disabled-2, retinoic acid fails to induce Disabled-2, correlating with a lack of growth suppression, although PA-1 is responsive to retinoic acid in morphological change. Transfection and expression of Disabled-2 in PA-1 cells mimic the effects of retinoic acid on growth suppression; the Disabled-2-expressing cells reach a much lower saturation density, and serum-stimulated c-Fos expression is greatly suppressed and disassociated from MAPK activation. Thus, Dab2 is one of the principal genes induced by retinoic acid involved in cell growth suppression, and expression of Dab2 alone is sufficient for uncoupling of MAPK activation and c-Fos expression. Resistance to retinoic acid regulation in PA-1 cells likely results from defects in retinoic acid up-regulation of Dab2 expression.     

Manipulations of the AVT system shift social status and related courtship and aggressive behavior in the bluehead wrasse

Arginine vasotocin (AVT) and its mammalian homologoue arginine vasopressin (AVP) influence male sexual and aggressive behaviors in many species. We tested the effects of AVT and an AVP-V(1a) receptor antagonist on the display of alternative male tactics in a tropical coral reef fish, the bluehead wrasse Thalassoma bifasciatum. We gave AVT injections to territorial and nonterritorial males of the large and colorful phenotype (terminal phase) and an AVP-V(1a) receptor antagonist, Manning compound, to territorial males in the field. AVT increased courtship independent of status, while its effects on territoriality and aggression were dependent upon male status. In territorial males, AVT increased courtship and tended to decrease the number of chases toward initial phase individuals. In nonterritorial males, AVT increased courtship, chases toward initial phase individuals, and territorial behavior while decreasing feeding. These are all behaviors rarely seen in nonterritorial males, so AVT made these males act like territorial TP males. The AVP-V(1a) receptor antagonist had opposite effects. It decreased courtship and territorial defense, making these males act more like nonterritorial males. Manipulations of the AVT system shifted males within a single phenotype from the nonterritorial social status to the territorial social status and vice versa. Since the entire suite of behaviors related to territoriality was affected by AVT system manipulations, our results suggest that the AVT system may play a key role in motivation of behaviors related to mating.     

Community health impacts of surface mining in the Upper West Region of Ghana: The roles of mining odors and dust

The emergence of the gold mining industry and the influx of artisanal and small-scale mining following recent discoveries of gold deposits in Northern Ghana have posed new socio-cultural, economic, environment and health challenges for residents in this dry savannah zone that is already facing negative consequences of environmental change. Yet, the extent to which residents in close proximity (impacted) and distant (affected) host communities perceive the impact of mining on their health has been nascent. Using cross sectional survey data (n=801) and applying the negative log-log regression technique, we examine residents’ self-rated health in mining communities in the Upper West Region of Ghana. The findings suggest that residents in impacted communities who believed that odors from mining activities could have health impact were twice more likely to report their health as poor, while those who were uncertain were 98% more likely to rate their health poor compared to those who disbelieved. However, sighting of dust was not significantly associated with subjective health in both impacted and affected communities. Based on these findings, it is recommended that Ghana's Minerals and Mining Act be reviewed to include the active involvement of host communities in mine leases while enforcing strict environmental best practices.     

Interactions among vegetable-infesting aphids,the fungal pathogen Metarhizium anisopliae (Ascomycota: Hypocreales) and the predatory coccinellid Cheilomenes lunata (Coleoptera: Coccinellidae)

Entomopathogenic fungi are among biocontrol agents being considered for the control of aphids on a variety of crops. Predatory coccinellids, although generalist, are also among important natural enemies that must be conserved for aphid management. Laboratory studies were carried out to investigate the interaction between three vegetable-infesting aphids, Metarhizium anisopliae isolate ICIPE 62 and the coccinellid predator Cheilomenes lunata. At a concentration of 1?×?10⁸?conidial?ml^–1, the fungus was found to cause mortality of 7.5% to C. lunata, compared to 2.5% mortality in the control at 10?days post-treatment. Female adult C. lunata to which fungus-infected aphids were offered as prey never accepted them as food source in non-choice bioassays. However, live and dead non-infected aphids were fed upon. In choice bioassay, a total of 1–3 out of 24 infected non-sporulating aphids per species (average of 0.1–0.4 aphids per arena) were consumed by 48?h-starved C. lunata within a period of 60?min, but avoided sporulating cadavers. Foraging adult C. lunata enhanced the spread of conidia of M. anisopliae from infected cadavers to fourth instars Aphis gossypii feeding on okra (0.8–15.0% mortality), Brevicoryne brassicae (3.3–15.0% mortality) and Lipaphis pseudobrassicae (0.8–14.2% mortality) on kale plants. Results of this study demonstrate compatibility between M. anisopliae and C. lunata, and could provide a sustainable strategy for effective management of aphids on crucifers and okra cropping systems.     

Clinical Trial of a New Diuretic,Furosemide: Comparison with Hydrochlorothiazide and Mercaptomerin

A clinical trial was carried out with the object of comparing the effects of furosemide, a new oral diuretic agent, with those of mercaptomerin and hydrochlorothiazide. Eleven edematous patients were chosen for the study and the diuretics were rotated, each drug being preceded by a one- to three-day control period. The patients served as their own controls. Urine electrolytes, body weight, and blood chemistry were monitored.Furosemide was shown to be an effective diuretic in this clinical study; under the conditions of the trial a single oral dose of 80 mg. of furosemide produced a natriuretic response in a 24-hour period equivalent to that achieved with a single oral dose of 100 mg. of hydrochlorothiazide or a single dose of 2.0 c.c. (80 mg. of mercury) of mercaptomerin given intramuscularly.