Animals have been a critical component of the spaceflight program since its inception. The Russians orbited a dog one month after the Sputnik satellite was launched. The dog mission spurred U.S. interest in animal flights. The animal missions proved that individuals aboard a spacecraft not only could survive, but also could carry out tasks during launch, near-weightlessness, and re-entry; humans were launched into space only after the early animal flights demonstrated that spaceflight was safe and survivable. After these humble beginnings when animals preceded humans in space as pioneers, a dynamic research program was begun using animals as human surrogates aboard manned and unmanned space platforms to understand how the unique environment of space alters life. In this review article, the following questions have been addressed: How did animal research in space evolve? What happened to animal development when gravity decreased? How have animal experiments in space contributed to our understanding of musculoskeletal changes and fracture repair during exposure to reduced gravity?
The bacterial disease American Foulbrood (AFB), caused by the Gram-positive bacterium Paenibacillus larvae, is considered the most contagious and destructive infectious disease affecting honeybees world-wide. The resilient nature of P. larvae bacterial spores presents a difficult problem for the control of AFB. Burning clinically symptomatic colonies is widely considered the only workable strategy to prevent further spread of the disease. Antibiotic use is banned in EU countries, and although used commonly in the U.S. and Canada, it only masks symptoms and does not prevent the further spread of the disease. Not surprisingly, there is an increased demand for chemical-free strategies to prevent and control of AFB. The aim of this study was to implement a management program with a long-term perspective to reduce infection pressure and eliminate AFB outbreaks. The study was conducted within a commercial beekeeping operation in central Sweden that has previously experienced reoccurring AFB outbreaks. For 5?years, P. larvae were cultured from adult bee samples taken in the fall. The following spring, any identified sub-clinically infected colonies were shaken onto new material and quarantined from the rest of the beekeeping operation. After the first year clinical symptoms were not again observed, and during the 5?years of the study the proportion of apiaries harbouring P. larvae spores decreased from 74% to 4%. A multinomial regression analysis also clearly demonstrated that the proportion of infected colonies with the highest levels of spore counts disproportionately declined so that by the end of the study the only remaining infected apiaries were in the lowest spore count category (the three higher spore count categories having been eradicated). These results demonstrate the importance of management practices on AFB disease epidemiology. Early detection of subclinical spore prevelance and quarantine management as presented here can provide an effective sustainable chemical-free preventive solution to reduce both the incidence of AFB outbreaks and continued transmission risk at a large-scale.
The idea that an aposematic prey combines crypsis at a distance with conspicuousness close up was tested in an experiment using human subjects. We estimated detectability of the aposematic larva of the swallowtail butterfly, Papilio machaon, in two habitats, by presenting, on a touch screen, photographs taken at four different distances and measuring the time elapsed to discovery. The detectability of larvae in these images was compared with images that were manipulated, using existing colours either to increase or decrease conspicuousness. Detection time increased with distance for all colourations. However, at the closest distance, detection time was longer for the larvae manipulated to be more cryptic than for the natural and more conspicuous forms. This indicates that the natural colouration is not maximally cryptic at a short distance. Further, smaller increments in distance were needed to increase detection time for the natural than for the conspicuous larva. This indicates that the natural colouration is not maximally conspicuous at longer distances. Taken together, we present the first empirical support for the idea that some colour patterns may combine warning colouration at a close range with crypsis at a longer range. The implications of this result for the evolution of aposematism are discussed.
Parasitological investigations of 529 specimens of 7 fish species from the water basins of the Khabarovsk Territory in 2009-2013 revealed the high extensity (11.7 to 100%) and intensity (as many as 9341 larvae per fish) of invasion with N. s. schikhobalowi metacercaria in salmonlike fishes from the mountain tributaries (Khor, Anyui, and Manoma) of the Amur river. The examined specimens of four salmonlike fish species (Thymallus tugarinae, Hucho taimen, Brachymystax tumensis and B. lenok) showed an increase in all indicators of infestation: invasion extensity (IE), invasion intensity (II), and abundance index (AI) with age. Moreover, IE peaked just in a 3-4-year-old fish (and in 1-year-old B. lenok) and further remained virtually unchanged. N. s. schikhobalowi metacercaria accumulated in the fish trunk with age, by maintaining their viability. With very high II, practically 100% infestation in B. lenok makes the population run the maximum risk of Nanophyetus infection with the dietary intake of this fish species if it is not disinfected. Examination of the distribution of N. s. schikhobalowi metacercaria in the trunk of Thymallus tugarinae showed that over 50% of larvae were detectable in the kidneys. This peculiarity of their localization could propose a simple method to determine II for Nanophyetus larvae in salmonlike fishes. Recommendations for reducing the risk of human infection with trematodes are given.
Multiple freeze-thaw cycles are common in alpine, polar and temperate habitats. We investigated the effects of five consecutive cycles of approx. -5 degrees C on the freeze-tolerant larvae of Pringleophaga marioni Viette (Lepidoptera: Tineidae) on sub-Antarctic Marion Island. The likelihood of freezing was positively correlated with body mass, and decreased from 70% of caterpillars that froze on initial exposure to 55% of caterpillars that froze on subsequent exposures; however, caterpillars retained their freeze tolerance and did not appear to switch to a freeze-avoiding strategy. Apart from an increase in gut water, there was no difference in body composition of caterpillars frozen 0 to 5 times, suggesting that the observed effects were not due to freezing, but rather to exposure to cold per se. Repeated cold exposure did not result in mortality, but led to decreased mass, largely accounted for by a decreased gut mass caused by cessation of feeding by caterpillars. Treatment caterpillars had fragile guts with increased lipid content, suggesting damage to the gut epithelium. These effects persisted for 5 days after the final exposure to cold, and after 30 days, treatment caterpillars had regained their pre-exposure mass, whereas their control counterparts had significantly gained mass. We show that repeated cold exposure does occur in the field, and suggest that this may be responsible for the long life cycle in P. marioni. Although mean temperatures are increasing on Marion Island, several climate change scenarios predict an increase in exposures to sub-zero temperatures, which would result in an increased generation time for P. marioni. Coupled with increased predation from introduced house mice on Marion Island, this could have severe consequences for the P. marioni population.
The purpose of this study was to describe the geographic distribution and model the ecological niche for Borrelia burgdorferi (Johnson, Schmidt, Hyde, Steigerwaldt & Brenner), Ixodes pacificus (Cooley & Kohls), and Ixodes angustus (Neumann), the bacterium and primary tick vectors for Lyme disease, in British Columbia (BC), Canada. We employed a landscape epidemiology approach using geographic information systems mapping and ecological niche modeling (Genetic Algorithm for Rule-set Prediction) to identify geographical areas of disease transmission risk. Forecasted optimal ecological niche areas for B. burgdorferi are focused along the coast of Vancouver Island, the southwestern coast of the BC mainland, and in valley systems of interior BC roughly along and below the N51 degree line of latitude. These findings have been used to increase public and physician awareness of Lyme disease risk, and prioritize future field sampling for ticks in BC.
Commercial fishing generally removes large and old individuals from fish stocks, reducing mean age and age diversity among spawners. It is feared that these demographic changes lead to lower and more variable recruitment to the stocks. A key proposed pathway is that juvenation and reduced size distribution causes reduced ranges in spawning period, spawning location, and egg buoyancy; this is proposed to lead to reduced spatial distribution of fish eggs and larvae, more homogeneous ambient environmental conditions within each year-class, and reduced buffering against negative environmental influences. However, few, if any, studies have confirmed a causal link from spawning stock demographic structure through egg and larval distribution to year class strength at recruitment. We here show that high mean age and size in the spawning stock of Barents Sea cod (Gadus morhua) is positively associated with high abundance and wide spatiotemporal distribution of cod eggs. We find, however, no support for the hypothesis that a wide egg distribution leads to higher recruitment or a weaker recruitment-temperature correlation. These results are based on statistical analyses of a spatially resolved data set on cod eggs covering a period (1959-1993) with large changes in biomass and demographic structure of spawners. The analyses also account for significant effects of spawning stock biomass and a liver condition index on egg abundance and distribution. Our results suggest that the buffering effect of a geographically wide distribution of eggs and larvae on fish recruitment may be insignificant compared with other impacts.
Cites: Proc Biol Sci. 2012 Jan 22;279(1727):275-83 PMID 21676978
Cites: Proc Natl Acad Sci U S A. 2012 Jun 5;109(23):8995-9 PMID 22615381
Cites: Glob Chang Biol. 2015 Mar 10;:null PMID 25758656
Cites: Proc Natl Acad Sci U S A. 2014 Mar 4;111(9):3478-83 PMID 24550465
Trichinellosis, a zoonotic disease caused by nematodes of the genus Trichinella, is still a public health concern in the Arctic. The aims of this study were to investigate the seroprevalence of anti-Trichinella IgG in aboriginal peoples of two settlements in the Chukotka Autonomous Okrug (Russian Federation) on the Arctic coast of the Bering Sea, and to evaluate the survival of Trichinella nativa larvae in local fermented and frozen meat products. A seroprevalence of 24.3% was detected in 259 people tested by an enzyme-linked immunosorbent assay (ELISA). The highest prevalence was detected among people who consumed traditional local foods made from the meat of marine mammals. Trichinella nativa larvae were found to survive for up to 24 months in a fermented and frozen marine mammal meat product called kopalkhen. Since the T. nativa life cycle can be completed in the absence of humans, it can be expected to persist in the environment and therefore remain a cause of morbidity in the human populations living in Arctic regions.