Molecular analysis of nutritional and hormonal regulation of female reproduction in the red flour beetle, Tribolium castaneum

Female reproduction includes maturation of oocytes and the synthesis of yolk proteins (vitellogenin, Vg) in the fat body and their deposition into the oocytes. Our recent studies showed that juvenile hormone (JH) regulates Vg synthesis and 20-hydroxyecdysone (20E) regulates oocyte maturation in the red flour beetle (Tribolium castaneum). Here, we report on the role of nutritional signaling on vitellogenesis and oogenesis. Comparison of gene expression between fed and starved beetles by microarray analysis showed the up-regulation of genes involved in energy homeostasis and down-regulation of genes involved in egg production in the starved beetles. The RNA interference (RNAi) aided knock-down in the expression of genes involved in insulin and TOR signaling pathways showed that both these signaling pathways play key roles in Vg synthesis and oocyte maturation. Starvation of female beetles resulted in a block in Vg synthesis but not in the progression of primary oocyte development to the resting stage. Feeding after starvation induced Vg synthesis and the progression of primary oocytes from the resting stage to the mature stage. However, in the beetles where JH or 20E synthesis or action was blocked by RNAi, both Vg synthesis and oocyte maturation were affected suggesting that both these hormones (JH and 20E) and nutritional signaling and their cross-talk regulate vitellogenesis and oogenesis.     

Local regulation of the uterine blood flow by the umbilical circulation.

Observations were made of the responses of the uterine blood flow in the near-term pregnancy to occlusion of the umbilical circulation to a few cotyledons of the near-term sheep placenta and in one placenta of the multiparous rabbit pregnancy. It was found that the uterine blood flow declined to 67% of its predicted value 1 day after umbilical ligation in the sheep placenta and to 61% of its predicted value 1 day after the death of one of the fetuses of the rabbit pregnancy. The change in the uterine blood flow in response to the occlusion of the umbilical blood supply to the adjacent area is a local response and is similar in its time course and magnitude to the response of the whole placenta which has been previously observed by Raye et al. (9). This local response of the uterine blood flow is considered to be evidence that the uterine blood flow is in part determined and controlled by the structural or chemical nature of the adjacent fetal compartment.     

Two-step photoperiodic and hormonal control of reproduction in the female beetle, Pterostichus nigrita

The carabid P. nigrita is a short-day/long-day insect. Short days with less than 15.0 hr of light per day induce pre-vitellogenesis. Vitellogenesis only takes place in subsequent long days with more than 13,1 hr of light. In the range from ld 13:11 to ld 16:8 egg production is possible without a change in photoperiod. Pre-vitellogenesis is induced by the corpus allatum hormone. Implantation of active corpora allata or injection of juvenile hormone substitutes for short-day photoperiods. Histological investigations and implantation experiments revealed that for vitellogenesis some neurosecretion is necessary. Ecdysterone cannot replace this neurosecretion.     

Facultative methanotrophy: false leads, true results, and suggestions for future research

Methanotrophs are a group of phylogenetically diverse microorganisms characterized by their ability to utilize methane as their sole source of carbon and energy. Early studies suggested that growth on methane could be stimulated with the addition of some small organic acids, but initial efforts to find facultative methanotrophs, i.e., methanotrophs able to utilize compounds with carbon-carbon bonds as sole growth substrates were inconclusive. Recently, however, facultative methanotrophs in the genera Methylocella, Methylocapsa, and Methylocystis have been reported that can grow on acetate, as well as on larger organic acids or ethanol for some species. All identified facultative methanotrophs group within the Alphaproteobacteria and utilize the serine cycle for carbon assimilation from formaldehyde. It is possible that facultative methanotrophs are able to convert acetate into intermediates of the serine cycle (e.g. malate and glyoxylate), because a variety of acetate assimilation pathways convert acetate into these compounds (e.g. the glyoxylate shunt of the tricarboxylic acid cycle, the ethylmalonyl-CoA pathway, the citramalate cycle, and the methylaspartate cycle). In this review, we summarize the history of facultative methanotrophy, describe scenarios for the basis of facultative methanotrophy, and pose several topics for future research in this area.     

Trade-offs between offspring fitness and future reproduction of adult female black brent

1.?Successful reproduction requires numerous decisions, and some of which may require trade-offs between current and future reproduction. We studied effects of choice of foraging patches on gosling growth and future breeding by mothers in black brent (Branta bernicla nigricans) geese. 2.?Specific foraging areas consistently produced high-quality goslings over 21?years. We found a consistent ranking of gosling mass, corrected for age, across brood rearing areas (BRAs) and years [Akaike model weights, Σw(i) =?1·00 for models including additive effects of BRA and year]. Growth of goslings largely determines their future fitness, so areas where goslings grew most rapidly also produced goslings with the highest mean fitness. 3.?We used a multistate robust design capture-mark-recapture approach to estimate the probability of transitioning from a breeding state to a non-breeding (unobservable) state as a function of quality of BRA. 4.?In the best supported model, transition from a breeding state to a non-breeding state was positively related to gosling growth rates across BRAs. Thus, future reproduction was lower for females using BRAs that produced higher-quality goslings. Our results are consistent with trade-offs by individual brent between fitness of their current offspring and their own reproductive value.     

Sophorolipid production by yeasts: a critical review of the literature and suggestions for future research

Applied Microbiology and Biotechnology - Sophorolipids are well-known biosurfactants produced by yeasts, having potential applications ranging from nanomaterials, medicine, and cosmetics to...     

The role of the leukocytes in the blood-vasal regulation of the blood circulation

The ability of N-formyl-methionyl-leucyl-phenylalanine-activated leukocytes to influence platelets and vessels was studied. It is shown, that of activation of leukocytes causes a vasoconstriction. The de-endothelialization of the vessels increased this effect. In addition, activated leukocytes increased the platelet aggregation. It was concluded, that activation of leukocytes can trigger thrombogenesis, angiospasm, microembolic syndrome and other disturbances of blood circulation.     

Effect of various antibiotics on the circulation of proteins between the blood and lymph in macro-organisms

The effect of tetracycline, amphotericin B and kefzol on distribution of some proteins between the blood and lymph of the thoracic duct was studied on rabbits. Tetracycline was injected intramuscularly in the form of hydrochloride dissolved in 2% novocain in a dose of 25 mg/kg once or daily for 7 and 20 days. Kefzol (sodium cephazolin) was injected intramuscularly in a single dose of 100 mg/kg. Amphotericin B was injected intravenously in a dose of 1000 Units/kg once or for 5 days. The lymph samples were collected from the thoracic duct of rabbits treated with single doses of the antibiotics 1 and 24 hours after their injection. When the animals were treated with the antibiotics repeatedly the lymph samples were collected 24 hours after the last injection. The level of the total protein and the ratio of the protein fractions, i. e. albumins, alpha 1-, alpha 2-, beta- and gamma-globulins in the lymph and blood serum were determined. On the basis of these findings the protein coefficient (albumin/globulin) of the lymph and blood, the coefficients of the protein permeability of the blood vessels (R) and the constants of selective permeability of the blood capillaries (S) were calculated. It was shown that the shifts in the protein circulation between the blood and lymph had mainly the same trends independent of the antibiotics used and their retention time in the host. A significant decrease in the permeability of the blood vessel walls in respect to the total protein and gamma-globulins and a marked increase in their selectivity in passing of the protein molecules of different size were observed in all cases.     

Plant water relations and the effects of elevated CO2: a review and suggestions for future research

Increased ambient carbon dioxide (CO₂) has been found to ameliorate water stress in the majority of species studied. The results of many studies indicate that lower evaporative flux density is associated with high CO₂-induced stomatal closure. As a result of decreases in evaporative flux density and increases in net photosynthesis, also found to occur in high CO₂ environments, plants have often been shown to maintain higher water use efficiencies when grown at high CO₂ than when grown in normal, ambient air. Plants grown at high CO₂ have also been found to maintain higher total water potentials, to increase biomass production, have larger root-to-shoot ratios, and to be generally more drought resistant (through avoidance mechanisms) than those grown at ambient CO₂ levels. High CO₂-induced changes in plant structure (i.e., vessel or tracheid anatomy, leaf specific conductivity) may be associated with changes in vulnerability to xylem cavitation or in environmental conditions in which runaway embolism is likely to occur. Further study is needed to resolve these important issues. Methodology and other CO₂ effects on plant water relations are discussed.Abbreviations A net photosynthesis - C_a ambient [CO₂] - C_i internal [CO₂] - E evaporative flux density - g₁ leaf conductance - g_s stomatal conductance - LSC leaf specific conductivity - IRGA infrared gas analyzer - LAI leaf area index - PAR photosynthetically active radiation - total plant water potential - _soil soil water potential - _s solute potential - _pt turgor pressure potential - _px xylem pressure potential - RH relative humidity - R : S root to shoot ratio - RWC relative water content - SLA specific leaf area - SLW specific leaf weight - SPAC soil-plant-atmosphere-continuum - SWC soil water content - VPD vapor pressure deficit - WUE water use efficiency     

Environmental, dietary, and hormonal factors in the regulation of seasonal breeding in free-living female Indian rose-ringed parakeets (Psittacula krameri)

The roles of environmental, dietary, and hormonal factors in the timing of seasonal breeding were assessed in free-living female Indian rose-ringed parakeets, Psittacula krameri, in northwest India (22 degrees 2'N, 73 degrees E). The ovaries and oviducts began to enlarge in January, were fully developed in February, and began to regress in March. During this time there was no significant change in the concentration of plasma luteinizing hormone (LH) or estradiol. The concentration of plasma LH decreased (P less than 0.01) at the end of the breeding season. Pair bond formation occurred between September and December and was associated with an increase in levels of plasma LH but no change in plasma estradiol. Concentrations of plasma testosterone (T) and 5 alpha-dihydrotestosterone (5 alpha-DHT) did not vary significantly during the year and were similar to those in males except for higher values of 5 alpha-DHT and lower values of T during the pre- and postbreeding periods, respectively. The similar levels of plasma androgens in both sexes may be related to the equal roles that both sexes play in the defence of their nest holes. An analysis of crop sac contents showed that the birds fed chiefly on pigeon peas (Cajanus cajan) during the breeding season and on cereal grains at other times of the year. It is suggested that pigeon peas provide the extra nutrients, including calcium, required for egg production. Since pigeon peas ripen between November and March, the production of the crop may play a role in the timing of seasonal breeding. A further factor appears to be competition for nest sites. By breeding in winter, the parakeet avoids competing with other species which nest in holes.     

The national disaster medical system: past, present, and suggestions for the future

This article reviews the history and structure of the National Disaster Medical System (NDMS), with an emphasis on its definitive care component. NDMS's capacity to handle very large mass casualty events, such as those included in the National Planning Scenarios, is examined. Following Hurricane Katrina, Congress called for a reevaluation of NDMS. In that context, we make three key suggestions to improve NDMS's capacity to respond to large mass casualty disasters: (1) increase the level of engagement by the private (i.e., nonfederal) healthcare system in preparedness and response efforts; (2) increase the reliance on regional hospital collaborative networks as part of the backbone of the NDMS system; and (3) develop additional, alternative patient transportation systems, linked to the overall NDMS patient tracking effort, to decrease the sole reliance on DoD long-haul air transport in medical evacuation.