Retention and adaptiveness of photoperiodic EGG diapause in Florida populations of invasive Aedes albopictus

Female Aedes albopictus, F2-F3 descendents from individuals collected as immatures at 6 geographic sites in the USA during 2008, exposed to short daylengths (10 h of light and 14 h of darkness at 21 degrees C) laid eggs in diapause, whose frequency depended upon population origin. Diapause responses in northern Florida and Illinois were strong, as had been reported approximately 10 years earlier for Ae. albopictus from these regions. For southern Florida, the diapause response was polymorphic, and its mean incidence decreased at 2 of 3 collection sites compared to 10 years earlier. Exposure in the field for 2- to 4-wk intervals in Vero Beach (lat 27 degrees 35'N) during January 2009 revealed that eggs laid by short-day females had significantly higher survivorship, even though <50% were estimated, from laboratory results, to be in diapause. Enhanced desiccation resistance may select for retention of diapause in southern Florida.

Sympathetic neural influence on bone metabolism in microgravity (Review)

Bone loss is one of the most important complications for astronauts who are exposed to long-term microgravity in space and also for bedridden elderly people. Recent studies have indicated that the sympathetic nervous system plays a role in bone metabolism. This paper reviews findings concerning with sympathetic influences on bone metabolism to hypothesize the mechanism how sympathetic neural functions are related to bone loss in microgravity. Animal studies have suggested that leptin stimulates hypothalamus increasing sympathetic outflow to bone and enhances bone resorption through noradrenaline and β-adrenoreceptors in bone. In humans, even though there have been some controversial findings, use of β-adrenoblockers has been reported to be beneficial for prevention of osteoporosis and bone fracture. On the other hand, microneurographically-recorded sympathetic nerve activity was enhanced by exposure to microgravity in space as well as dry immersion or long-term bed rest to simulate microgravity. The same sympathetic activity became higher in elderly people whose bone mass becomes generally reduced. Our recent findings indicated a significant correlation between muscle sympathetic nerve activity and urinary deoxypyridinoline as a specific marker measuring bone resorption. Based on these findings we would like to propose a following hypothesis concerning the sympathetic involvement in the mechanism of bone loss in microgravity: An exposure to prolonged microgravity may enhance sympathetic neural traffic not only to muscle but also to bone. This sympathetic enhancement increases plasma noradrenaline level and inhibits osteogenesis and facilitates bone resorption through β-adrenoreceptors in bone to facilitate bone resorption to reduce bone mass. The use of β-adrenoblockers to prevent bone loss in microgravity may be reasonable.

Polyamine-promoted autoactivation of plasma hyaluronan-binding protein

BACKGROUND

Plasma hyaluronan-binding protein (PHBP), a protease implicated in extracellular proteolysis, consists of multiple domains: an N-terminal region (NTR), three epidermal growth factor (EGF)-like domains, a kringle domain, and a protease domain. PHBP circulates as a single-chain proenzyme (pro-PHBP), which is converted to an active, two-chain form through autoproteolysis.

OBJECTIVE

To understand the mechanism of autoactivation. Here, we report that polyamine induces the formation of pro-PHBP autoactivation complex, in which an intermolecular interaction between NTR and the third EGF-like domain (E3) plays a role.

METHODS

Using a series of pro-PHBP mutants that partially lack functional domains, polyamine-induced pro-PHBP autoactivation was investigated in terms of enzyme activity, protein interaction, and inhibition by carminic acid, an anthraquinone compound identified in this study.

RESULTS

Polyamine enhanced intermolecular binding of pro-PHBP, but not of mutant pro-PHBP that partially lacked NTR (DeltaN). Carminic acid inhibited intermolecular pro-PHBP binding and specifically abolished polyamine-induced autoactivation. NTR bound to pro-PHBP and DeltaN, but its binding was minimal to a mutant that lacked E3. The NTR-DeltaN binding was inhibited by a combination of polyamine and carminic acid, but each compound alone was ineffective.

CONCLUSIONS

We infer from the data that (i) polyamine modulates intramolecular NTR-E3 interaction to allow intermolecular binding between NTR and E3 in another pro-PHBP molecule to form an autoactivation complex, and (ii) carminic acid inhibits polyamine-modulated intermolecular NTR-E3 binding. Polyamine concentrations are higher in cells and tissues with inflammation and malignancy. Polyamine leakage from legions through cell death or tissue injury may account for physiologically relevant pro-PHBP activation.

Expression of estrogen receptor and proto-oncogene messenger ribonucleic acids in reproductive tracts of neonatally diethylstilbestrol-exposed female mice with or without post-puberal estrogen administration

Perinatal treatment of female mice with natural and synthetic estrogens including diethylstilbestrol (DES) results in estrogen-independent persistent proliferation and cornification of the vaginal epithelium. The dynamics of the induction of estrogen receptor (ER), c-jun, c-fos and c-myc mRNAs by 17 beta-estradiol (E2) was examined in the uterus and vagina of neonatally DES-exposed and -unexposed ovariectomized adult mice. In the uterus of neonatally DES-unexposed ovariectomized mice, the expression of ER mRNA increased within 1 h after E2 administration and declined by 12 h thereafter. ER mRNA in the vagina decreased within 1 h after the stimulation and recovered by 12 h thereafter. In the uterus, c-jun and c-fos mRNAs increased in concentration within 1 h after E2 administration, showing a peak 3 h after the stimulation; they decreased with time thereafter. In the vagina, the concentration of c-jun and c-fos mRNAs increased rapidly, reaching a peak within 1 h after the stimulation. However, the expression of c-myc in uterus and vagina was not changed by postpuberal E2. These results suggest that estrogen regulation of ER and proto-oncogene mRNAs in the vagina differs from those in the uterus. In the neonatally DES-exposed ovariectomized adult mice, uterine ER mRNA expression levels were significantly higher than in the unexposed ovariectomized controls; however, vaginal levels were drastically lower than in the controls. Expression of c-jun and c-fos mRNAs was greater in both the uterus (3- and 6-fold, respectively) and the vagina (18- and 4-fold) of neonatally DES-exposed mice than in controls. The ER mRNA and the increased levels of c-fos and c-jun mRNAs in both uterus and vagina of neonatally DES-exposed ovariectomized mice were not further altered by post-puberal E2 and may be related to ovary-independent persistent changes in the genital tract.