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The migration of the germ of the 2nd lower molars after the extraction of all adjacent teeth in comparison to the health side was investigated in Vietnamese hanging belly pigs. The animals were killed in seven age groups so that the results could be evaluated in dependence upon the time. The biometric results reveal migratory phenomena similar to those described for humans after tooth extraction.
Phagocytosis of urate crystals by human or rabbit neutrophils induces the synthesis and release of a glycoprotein, the crystal-induced chemotactic factor (CCF), which is chemotactically active both in vitro and in vivo. It has been proposed that CCF is a prime mediator of the acute gouty attack. Colchicine has been shown to decrease the production and release of this factor in vitro. In these studies, colchicine, at nonleukopenic doses, is shown to abrogate the acute arthritis induced by monosodium urate crystals in rabbits, but to have no effect upon the arthritis induced by the injection of the purified cell-derived chemotactic factor. Serum colchicine levels were 0.48-0.58 muM at 30 min and 0.12-0.3 muM at 90 min after intravenous injection of 0.2 mg/kg colchicine. Peripheral blood polymorphonuclear leukocytes obtained from colchicine-treated animals migrated normally towards a chemotactic stimulus but failed to produce CCF after phagocytosis of monosodium urate crystals. The dialyzed synovial fluid from rabbits injected with microcrystalline sodium urate contained chemotactic activity that was not present when animals were also given intravenous colchicine or injected intra-articularly with the chemotactic factor formyl-methionyl-leucyl-phenylalanine. Furthermore, the synovial fluid from rabbits injected with microcrystalline sodium urate significantly decreased (125)I-CCF binding to neutrophils. The binding of (125)I-CCF to its neutrophil receptor was not significantly reduced by the synovial fluid of colchicine-treated rabbits nor by the synovial fluid of control rabbits injected with the chemotactic factor formyl-methionyl-leucyl-phenylalanine. Colchicine (10 and 0.1 muM) was shown to have no effect upon the binding of (125)I-CCF to its cell receptor.
In vivo behavior of 111In-DTPA in rat and mouse after intra-ventricular administration was studied. Thus, 50 muCi and 35 muCi of 111In-DTPA was injected intra-ventricularly to rat and mouse respectively. At specific time intervals, the animals were sacrificed, then distribution in organs was determined by radioactivity counting and autoradiographic method. Urinary and fecal excretion were separately collected and excretion rates were estimated. Metabolites in urine of rat were examined with chromatography. A part of 111In-DTPA injected intra-ventricularly to the animals migrated to subarachnoid space, then radioactivity in cerebrospinal fluid effused into blood with about 1 hr initial half-life. Blood clearance was also rapid, about 1 hr after administration the blood level reached maximum and then decreased showing an initial half-life of about 1 hr. The predominant excretion route in rat was urinary and about 90% and 5% of administered dose were excreted within 48 hr through urine and feces respectively. Judging from the Rf-value of radioactivity peak on chromatograms, 111In-DTPA seems to be excreted without suffering any metabolic change. Concerning to the behavior of 111In-DTPA in male and female rat, no difference was observed, and the distribution pattern of 111In-DTPA in mouse was similar to that of rat.
Range expansions can result in founder effects, increasing genetic differentiation between expanding populations and reducing genetic diversity along the expansion front. However, few studies have addressed these effects in long-distance migratory species, for which high dispersal ability might counter the effects of genetic drift. Monarchs (Danaus plexippus) are best known for undertaking a long-distance annual migration in North America, but have also dispersed around the world to form populations that do not migrate or travel only short distances. Here, we used microsatellite markers to assess genetic differentiation among 18 monarch populations and to determine worldwide colonization routes. Our results indicate that North American monarch populations connected by land show limited differentiation, probably because of the monarch's ability to migrate long distances. Conversely, we found high genetic differentiation between populations separated by large bodies of water. Moreover, we show evidence for serial founder effects across the Pacific, suggesting stepwise dispersal from a North American origin. These findings demonstrate that genetic drift played a major role in shaping allele frequencies and created genetic differentiation among newly formed populations. Thus, range expansion can give rise to genetic differentiation and declines in genetic diversity, even in highly mobile species.
Among movement strategies, migratory behavior is particularly intriguing in insects. Home-breeding is often permanent, and return journeys can take several generations. Although migration is crucial to the ecological and evolutionary processes of the species involved, knowledge of insect migratory behavior needs to be better understood. Vanessa carye, a butterfly native to South America with a latitudinal range of ∼7,000 km, exemplifies this problem. This study analyzed samples collected across the species' range using single-nucleotide polymorphisms (SNPs) to assess population structure, genetic diversity, and geometric morphometrics to examine wing shape variation. Results indicate that V. carye forms a genetically homogeneous unit composed of only two potential populations spanning ∼5,000 km, geographically correlated with the Pacific Ocean and the Andes, maintaining constant gene flow, and with a mean heterozygosity of 5.74% (SE: ±0.048%). Geometric morphometrics detected no geographic differentiation in wing shapes and sizes across ∼7,000 km, suggesting an absence of local adaptation and indicating a conserved wing shape adapted to flight throughout the species' range. Our findings support V. carye as a migratory species with the longest migratory journey among American butterflies, revealing two migratory routes. With these approaches, we provide a consistent methodological framework for migratory studies in species with important gaps in knowledge of their natural history.
Differential dispersion between the sexes can impact the colonization process and demographic history of a species. Here, we explored the demographic history of the big European firefly, Lampyris noctiluca, which exhibits female neoteny. Distribution of L. noctiluca extends throughout Europe, but nothing is known about its colonization process. To investigate its demographic history, we produced the first Lampyris genome (653 Mb), including an IsoSeq annotation and the identification of the X chromosome. We collected 115 individuals from six populations of L. noctiluca (Finland to Italy) and generated whole-genome re-sequencing data for each individual. We inferred several population expansions and bottlenecks throughout the Pleistocene that correlate with glaciation events. Surprisingly, we uncovered strong population structure and low gene flow. We reject a stepwise, south to north, colonization history scenario and instead uncovered a complex demographic history with a putative eastern European origin. Analyzing the evolutionary history of the mitochondrial genome as well as X-linked and autosomal loci, we found evidence of a maternal colonialization of Germany, putatively from a farther western European population, followed by a male-only migration from south of the Alps (Italy). Overall, investigating the demographic history and colonization patterns of a species should form part of an integrative approach of biodiversity research. Our results provide evidence of sex-biased migration which is important to consider for demographic, biogeographic and species delimitation studies.
BACKGROUND: Monarch butterflies (Danaus plexippus) are a charismatic and culturally important North American butterfly species famous for their unique, dramatic migratory life history. While non-migratory populations of the species are widespread and apparently stable, migratory populations in North America have recently seen declines, prompting concern that the migratory phenomenon in North America may be at risk of disappearing. In contrast, a relatively recently-established monarch population in Australia has rapidly re-acquired a migratory life history following hundreds of generations of residency and successive bottlenecks as the species island-hopped across the Pacific during the late 1800s and early 1900s. The process by which migration re-emerged in Australian monarchs is not currently known. RESULTS: We raised and sequenced individuals from Queensland, Australia under environmental conditions associated with migration initiation and found strong variance in reproductive diapause, a key migratory trait, between families which was associated with variation at the spectrin beta chain protein Karst. This protein is known to be involved in diapause termination in monarchs but has not previously been identified as associated with migratory life history variance. The most strongly associated migratory SNPs are also present at a low frequency in North America, suggesting that the Australian population is leveraging standing variation which persisted across repeated bottlenecks as Monarchs spread across the Pacific. CONCLUSIONS: Our results provide an intriguing example of how the temporary loss of migration-in this case likely over hundreds of generations-may not entail the loss of genetic variation associated with this complex life history strategy.
Three weeks after hypophysectomy mitosis and DNA synthesis are absent in the lens of the leopard frog (Rana iiens). By labeling germinative zone cells in their last DNA synthetic period we were able to follow them in the absence of further proliferation. By this means it has been demonstrated that migration of epithelial cells to the equator of the lens is stopped. Based on indirect measurements it seems that lens fiber formation also ceases. A correlation coefficient of 0.86 was computed between average labeling index and average distance migrated. In hypophysectomized animals the correlation coefficient between time and migration was 0.02 while in intact animals it is 0.87.
The effect of insulin on the electrical activity of the small intestine was studied in both normal and alloxan induced diabetic sheep. In normal animals the migrating myoelectric complexes recur at intervals of about 90 min. In the diabetic sheep, the complexes recur at only 2 hourly intervals and administration of insulin restored the pattern to normal. Since in normal sheep, insulin slightly increases the activity and volatile fatty acids, which release insulin do likewise, one may conclude that insulin may control the activity of the gut.
Steelhead/rainbow trout (Oncorhynchus mykiss) is an imperilled salmonid with two main life history strategies: migrate to the ocean or remain in freshwater. Domesticated hatchery forms of this species have been stocked into almost all California waterways, possibly resulting in introgression into natural populations and altered population structure. We compared whole-genome sequence data from contemporary populations against a set of museum population samples of steelhead from the same locations that were collected prior to most hatchery stocking. We observed minimal introgression and few steelhead-hatchery trout hybrids despite a century of extensive stocking. Our historical data show signals of introgression with a sister species and indications of an early hatchery facility. Finally, we found that migration-associated haplotypes have become less frequent over time, a likely adaptation to decreased opportunities for migration. Since contemporary migration-associated haplotype frequencies have been used to guide species management, we consider this to be a rare example of shifting baseline syndrome that has been validated with historical data. We suggest cautious optimism that a century of hatchery stocking has had minimal impact on California steelhead population genetic structure, but we note that continued shifts in life history may lead to further declines in the ocean-going form of the species.
The ecoevolutionary drivers of species niche expansion or contraction are critical for biodiversity but challenging to infer. Niche expansion may be promoted by local adaptation or constrained by physiological performance trade-offs. For birds, evolutionary shifts in migratory behavior permit the broadening of the climatic niche by expansion into varied, seasonal environments. Broader niches can be short-lived if diversifying selection and geography promote speciation and niche subdivision across climatic gradients. To illuminate niche breadth dynamics, we can ask how "outlier" species defy constraints. Of the 363 hummingbird species, the giant hummingbird (Patagona gigas) has the broadest climatic niche by a large margin. To test the roles of migratory behavior, performance trade-offs, and genetic structure in maintaining its exceptional niche breadth, we studied its movements, respiratory traits, and population genomics. Satellite and light-level geolocator tracks revealed an >8,300-km loop migration over the Central Andean Plateau. This migration included a 3-wk, ~4,100-m ascent punctuated by upward bursts and pauses, resembling the acclimatization routines of human mountain climbers, and accompanied by surging blood-hemoglobin concentrations. Extreme migration was accompanied by deep genomic divergence from high-elevation resident populations, with decisive postzygotic barriers to gene flow. The two forms occur side-by-side but differ almost imperceptibly in size, plumage, and respiratory traits. The high-elevation resident taxon is the world's largest hummingbird, a previously undiscovered species that we describe and name here. The giant hummingbirds demonstrate evolutionary limits on niche breadth: when the ancestral niche expanded due to evolution (or loss) of an extreme migratory behavior, speciation followed.
In the wake of pandemics like COVID-19, which have zoonotic origins, the role of wildlife as reservoirs for emerging infectious diseases has garnered heightened attention. Migratory birds, traversing continents, represent a potent but under-researched vector for the spread of infectious diseases, including novel coronaviruses. This study delves into the genetic diversity and transmission dynamics of coronaviruses in migratory birds, presenting pivotal findings. From April 2019 to April 2023, we screened 5,263 migratory bird samples collected from Shanghai, China, identifying 372 coronavirus-positive samples belonging to five avian-related coronavirus subgenera and subsequently obtaining 120 complete genome sequences. To facilitate further research with a global perspective, the study curated all available 19,000 avian-associated coronaviruses and expanded the original 12 species to 16, including three novel coronavirus species identified in our study and one re-classified species from the public domain. The study illuminates the intricate genetic evolution and transmission dynamics of birds-related coronaviruses on a global scale. A notable aspect of our research is the identification of complex recombination patterns within the spike protein across different virus species and subgenera, highlighting migratory birds as a reservoir of coronavirus. Notably, the coronaviruses found in migratory birds, predominantly from the orders Anseriformes, Charadriiformes, and Pelecaniformes, with domestic ducks from Anseriformes playing a key role in bridging the transmission of coronaviruses between migratory and non-migratory birds. These findings reveal the genetic and recombination characteristics of coronaviruses in migratory birds, emphasizing the critical role of ecologically pivotal bird species in coronavirus transmission and genetic diversity shaping.
A study was made of the phenotypical manifestation of physiological polymorphism of the population of the grass frog by the heat resistance level of m. interphalangealis in different seasons. In autumn (starting from the 2nd half of October), throughout winter, and in summer the polymorphism of frogs is well expressed, whereas in spring (during the reproduction period) and in the first half of October (during the migration of animals to the places of hibernation) the polymorphism appears to be hidden. The latter phenomenon is due to differences in the pattern of individual seasonal changes in the heart resistance of muscles in individuals of different groups.
Guiena pigs were immunized with dinitrophenyl-keyhole limpet hemocyanin (DNP-KLH) or with hemocyanin in complete Freud's adjevant. The migration of oil-induced peritoneal exudate cells was measured in the presence and absence of epsilon-dinitrophenyl-lysine-tyrosinyl Ficoll (DNPL-F). When the cells came from animals immunized with DNP-KLH their migration was inhibited by DNPL-F. Control cells from animals immunized with KLH or not immunized migrated normally in the presence of DNPL-F.
Several synthetic peptide analogues of the amino terminal antigenic determinant (ala-tyr-lysile-ala-asp-ser) of oxidized ferredoxin (O-Fd) were tested for their ability to inhibit the complement fixation reaction between O-Fd and homologous rabbit antiserum, and to inhibit the migration of spleen cells from guinea-pigs immunized to O-Fd or to a conjugate of the amino terminal heptapeptide (N7) and bovine serum albumin (N7-BSA). The results of the migration inhibition assay suggest that the tetrapeptide and longer peptides of the native sequence were all recognized and stimulated the production of migration inhibition factor. Peptides modified at the aspartic residue were partially active while the serine modified peptide was not. Modification at the amino end of the heptapeptide had no effect on migration inhibition. As specificity controls, it was shown that the N7-BSA conjugate inhibited migration in O-Fd immunized animals, while O-Fd inhibited migration in N7-BSA immunized animals. The hexa-, hepta-, aspartic-deleted and serine-modified peptides were able to inhibit the complement fixation reaction with O-Fd and specific rabbit antiserum. Inhibition found with the serine-modified peptide and the lack of inhibition with the amino-modified peptide or the di-, tri-, tetra- and pentapeptides indicates the determinant recognized by the rabbit antibodies is either larger or is located nearer the middle of the heptapeptide than the determinant which induced the production of MIF.
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Lymphocytes from patients with neoplastic disease were tested for sensitization to encephalitogenic factor (EF) by the macrophage migration inhibition test. Sensitization to EF was demonstrated in 71% of patients with various forms of neoplastic disease. Sensitization to EF was also demonstrated for 31% of subjects with no evidence of neoplastic disease; these included patients with warts, chronic bronchitis and hernias. In contrast, healthy subjects showed no sensitization to myelin basic protein. These observations suggest that sensitization to EF may not be confined to patients with neoplastic disease. Lymphocytes from hamsters bearing a transplanted virus induced tumour were sensitized to EF prepared from both human and hamster brain. Sensitization was also seen in hamsters infected with influenza virus but not in animals with acute tubular necrosis produced by glycerol treatment. The development of an animal model system provides a method for the investigation of possible mechanisms of sensitization.
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