Journal articles: 'Twin species'

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Bazalová, Denisa, Katarína Botková, Katarína Hegedüšová, Jana Májeková, Jana Medvecká, Mária Šibíková, Iveta Škodová, Mária Zaliberová, and Ivan Jarolímek. "Twin plots – appropriate method to assess the impact of alien tree on understory?" Hacquetia 17, no. 2 (December 1, 2018): 163–69. http://dx.doi.org/10.1515/hacq-2017-0012.

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Abstract Replacing native forests by alien tree plantations can lead to changes in the species composition of the understory. However, differences in the understory species spectrum can also be a part of the natural variability of forest stands. We have tested the suitability of the twin plots method for an evaluation of the impact of alien trees on the species composition of the understory. This research was conducted on an alluvial plain (SW Slovakia) that was originally covered by a hardwood floodplain forest. The study was based on 7 twin plots of black locust (Robinia pseudoacacia) and native forest plots, with a maximum distance of 100 meters between the members of the twins. The dissimilarity of the plots within the black locust forest was significantly lower than the dissimilarity between the twin plots. In addition, the dissimilarity of the plots within the hardwood floodplain forest was also significantly lower than the dissimilarity between the twin plots. Under the same environmental conditions, the higher dissimilarity of the twin plots was caused by major edificators and their impact on the understory vegetation. The twin plots method proved to be a suitable tool for analyses of the impact of alien trees on understory vegetation.

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St Clair, John, Roisin Campbell-Palmer, and Richard Lathe. "Sex Ratios Provide Evidence for Monozygotic Twinning in the Ring-Tailed Lemur,Lemur catta." Twin Research and Human Genetics 17, no. 1 (January 2, 2014): 51–55. http://dx.doi.org/10.1017/thg.2013.84.

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Monozygotic (MZ) twinning is generally considered to be rare in species other than human. We inspected sex ratios in European zoo-bred ring-tailed lemurs (Lemur catta), revealing a significant excess of same-sex twins. Of 94 pairs, 60 (64%) were either both males or both females (p= .004). Application of the Weinberg differential rule argues that 27% of all twins in this species are MZ pairs. In this protected species, where twinning is commonplace (~50% of newborns are twins), the probable existence of frequent MZ twinning has ramifications for breeding programs aimed to maximize genetic diversity, and suggests that twin studies in a species other than human could have potential as a medical research tool.

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Pavan, L., B. Gasser, V. J. C. Santos, M. C. Maronezi, P. Silva, A. R. Assis, P. H. S. Garcia, R. Martins Junior, R. A. R. Uscategui, and M. A. R. Feliciano. "Ultrasonographic diagnosis of twins in two pregnant bitches: case report." Arquivo Brasileiro de Medicina Veterinária e Zootecnia 72, no. 1 (January 2020): 102–6. http://dx.doi.org/10.1590/1678-4162-11331.

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ABSTRACT Multiple pregnancies in humans account for only 3% of pregnancies, 97-98% of which are twin pregnancies and the morbimortality is higher in the monochorionic twins when compared to dichorionic ones. The canine species is naturally multiparous, but the diagnosis of monochorionic twin pregnancy is not common. The objective of this report was to describe the ultrasonographic diagnosis of monochorionic twin pregnancies in two bitches [Pug (case 1) and Shih tzu (case 2)]. It was possible to verify the presence of one gestational vesicle containing two fetuses in each female by observing two heads or two bodies within the same placental site. These fetuses presented adequate viability and normal organogenesis. Their development was similar to the other fetuses. In case 1 they were stillborn and smaller than the other five live-born fetuses. The twins in case 2 were born alive, but they also appeared smaller when compared to the littermates. The gestational risks associated with this condition in pregnant bitches are still unknown, however, there are reports of fetal death in monochorionic pregnancies in this species. Therefore, ultrasonographic exam during pregnancy allows an early monochorionic diagnosis and monitoring the fetal viability could bring health benefits to both the female and the littermates.

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Shaughnessy, P., and E. Erb. "Apparent twin pups of the Weddell seal Leptonychotes weddellii (Carnivora: Phocidae) near Mawson, Antarctica." Australian Mammalogy 25, no. 2 (2003): 197. http://dx.doi.org/10.1071/am03197.

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PHOCID seals give birth annually, generally to a single pup. Twins have been reported occasionally, either from observations made in utero or from observations of live pups in the field. Examples of the former are reports of two embryos in a Weddell seal, Leptonychotes weddellii (Bertram 1940) and of twin foetuses of a southern elephant seal, Mirounga leonina (Bryden 1966). Observations of two pups suckling one adult female have been reported for L. weddellii (e.g., Gelatt et al. 2001). For M. leonina, Carrick et al. (1962) reported an adult female that expelled two placentae and gave birth to a pup while another newborn pup was nuzzling the female. The occurrence of twin pups in several pinniped species is reviewed by Spotte (1982). Here we use the expression 'apparent twins' to refer to reports of twin L. weddellii pups that are based solely on field observations of two pups with the same adult female on several occasions.

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Watkins, D. I., Z. W. Chen, A. L. Hughes, F. S. Hodi, and N. L. Letvin. "Genetically distinct cell populations in naturally occurring bone marrow-chimeric primates express similar MHC class I gene products." Journal of Immunology 144, no. 10 (May 15, 1990): 3726–35. http://dx.doi.org/10.4049/jimmunol.144.10.3726.

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Abstract The cotton-top tamarin (Saguinus oedipus) is a naturally occurring "A" + "B"----"A" bone marrow-chimeric species. These primates usually are born as dizygotic twins and, due to placental vascular anastomoses, develop sharing each others' bone marrow elements. Strikingly, almost 50% of the PBL of a member of a twin pair are derived from the hematopoietic stem cells of its cotwin. To clarify the mechanisms underlying the maintenance of tolerance in these stable chimeras, MHC gene products have been biochemically characterized in cloned, genetically distinct, male and female lymphocytes from two male/female cotton-top tamarin twin pairs. Extensive MHC class II sharing between the genetically distinct cell populations was not seen in the two twin pairs. This was consistent with the MHC class II polymorphism seen in the species. However, the MHC class I gene products expressed by one member of a twin pair were almost identical to those expressed by its cotwin. A human minisatellite probe demonstrated restriction fragment length polymorphism in DNA from these animals, indicating extensive polymorphism. Thus, MHC class I sharing did not occur due to inbreeding in these animals. Additionally, another bone marrow-chimeric primate species, the common marmoset (Callithrix jacchus), expresses MHC class I molecules with low levels of variation. These studies suggest that the stable chimerism of bone marrow-chimeric primates may be facilitated by MHC class I similarity between the genetically distinct bone marrow derived-cell populations in their circulation.

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Britt, Lyle L., Ellis R. Loew, and William N. McFarland. "Visual pigments in the early life stages of Pacific northwest marine fishes." Journal of Experimental Biology 204, no. 14 (July 15, 2001): 2581–87. http://dx.doi.org/10.1242/jeb.204.14.2581.

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SUMMARY Microspectrophotometry was used to measure the visual pigments in the rods and cones of 22 species of marine fish larvae netted from the surface waters off Friday Harbor Laboratories, Washington, USA. 13 species had rods, 12 of which contained visual pigments with a wavelength of maximum absorbance near 500nm, while one, the sand lance (Ammodytes hexapterus), had its absorbance maximum at 482nm. The 22 species of fish larvae possessed varied combinations of single, double and twin cones, ranging in peak absorbance from 353nm to 584nm. Of these, green-sensitive single cones were present in 20 of the 22 species, and were the dominant cone type. Double and twin cones were present in 13 of the species. Most common were identical green-sensitive (twin) cones (in 11 species). Green/yellow-sensitive double cones occurred in four species. In a single instance (Hemilepidotus hemilepidotus) twin blue-sensitive, twin green-sensitive and double blue/yellow-sensitive cones were recorded. Of particular interest was the finding that 18 of the species had ultraviolet- and/or violet-absorbing single cones. It has been suggested that short-wavelength photosensitivity may be beneficial for planktivory by extending the spectral range over which vision can occur. The high percentage (82%) of ultraviolet and violet visual pigments in Pacific northwest fish larvae supports the prediction that short-wavelength sensitivity may be common in marine fish larvae.

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Corby, Patricia M., Walter A. Bretz, Thomas C. Hart, Nicholas J. Schork, J. Wessel, James Lyons-Weiler, and Bruce J. Paster. "Heritability of Oral Microbial Species in Caries-Active and Caries-Free Twins." Twin Research and Human Genetics 10, no. 6 (December 1, 2007): 821–28. http://dx.doi.org/10.1375/twin.10.6.821.

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AbstractOral microbes that colonize in the mouths of humans contribute to disease susceptibility, but it is unclear if host genetic factors mediate colonization. We therefore tested the hypothesis that the levels at which oral microbes colonize in the mouth are heritable. Dental plaque biofilms were sampled from intact tooth surfaces of 118 caries-free twins. An additional 86 caries-active twins were sampled for plaque from carious lesions and intact tooth surfaces. Using a reverse capture checkerboard assay the relative abundance of 82 bacterial species was determined. An integrative computational predictive model determined microbial abundance patterns of microbial species in caries-free twins as compared to caries-active twins. Heritability estimates were calculated for the relative microbial abundance levels of the microbial species in both groups. The levels of 10 species were significantly different in healthy individuals than in caries-active individuals, including,A. defectiva, S. parasanguinis, S. mitis/oralis, S. sanguinis, S. cristatus, S. salivarius, Streptococcussp. clone CH016,G. morbillorumandG. haemolysans.Moderate to high heritability estimates were found for these species (h2= 56%–80%,p< .0001). Similarity of the overall oral microbial flora was also evident in caries-free twins from multivariate distance matrix regression analysis. It appears that genetic and/or familial factors significantly contribute to the colonization of oral beneficial species in twins.

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Mette, Tobias, Susanne Brandl, and Christian Kölling. "Climate Analogues for Temperate European Forests to Raise Silvicultural Evidence Using Twin Regions." Sustainability 13, no. 12 (June 8, 2021): 6522. http://dx.doi.org/10.3390/su13126522.

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Climate analogues provide forestry practice with empirical evidence of how forests are managed in “twin” regions, i.e., regions where the current climate is comparable to the expected future climate at a site of interest. As the twin regions and their silvicultural evidence change with each climate scenario and model, we focus our investigation on how the uncertainty in future climate affects tree species prevalence. We calculate the future climate from 2000 to 2100 for three ensemble variants of the mild (representative concentration pathway (RCP) 4.5) and hard (RCP 8.5) climate scenarios. We determine climatic distances between the future climate of our site of interest ‘Roth’ and the current climate in Europe, generating maps with twin regions from 2000 to 2100. From forest inventories in these twin regions we trace how the prevalence of 23 major tree species changes. We realize that it is not the ‘how’ but the ‘how fast’ species’ prevalence changes that differs between the scenario variants. We use this finding to develop a categorization of species groups that integrates the uncertainty in future climate. Twin regions provide further information on silvicultural practices, pest management, product chains etc.

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Negi, Pitambar. "Occurrence of Polyembryony in Juniperus Polycarpos C. Koch." Indian Journal of Forestry 37, no. 2 (June 1, 2014): 161–64. http://dx.doi.org/10.54207/bsmps1000-2014-gsvahs.

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The natural regeneration in Juniperus polycarpos is quite low due to seed dormancy. While studying the seed germination behaviour of Juniperus polycarpos, a twin seedling was found germinated from a single seed which has been reported. This is the first instance of occurrence of polyembryonic seedlings in Juniperus polycarpos which have been reported in this paper. The twin seedlings have been resulted due to the phenomenon of polyembryony which is of rare occurrence in this species, however, the production of twin seedlings has been reported earlier also in other forest tree species. The twin seedlings were found to be independent having separate taproots and cotyledons. The seedlings were later transplanted in a polybags filled with Soil: Sand: FYM (2:1:1 :) to observe the further growth of twin seedlings. After three months, it was noticed that both the twin seedlings shriveled and died where as normal seedlings continued to grow normally and produced all the essential features of a plant.

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Gunaga, Rajesh, and R. Vasudeva. "A New report on twin seedlings in Semecarpus Kathalekanensis, a critically endangered tree species of the Myrisitca swamps of Western Ghats." Journal of Non-Timber Forest Products 18, no. 4 (December 1, 2011): 331–32. http://dx.doi.org/10.54207/bsmps2000-2011-6yu7cz.

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In this paper, observation on twin seedlings in Semecarpus kathalekanensis is reported. Out of 850 seeds germinated (from seven individuals), two seeds gave out twin seedlings. Further, the growth of twin seedlings with normal seedlings have been recorded and discussed here.

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Gunaga, Rajesh, and R. Vasudeva. "A New report on twin seedlings in Semecarpus Kathalekanensis, a critically endangered tree species of the Myrisitca swamps of Western Ghats." Journal of Non-Timber Forest Products 18, no. 4 (December 1, 2011): 331–32. http://dx.doi.org/10.54207/bsmps2000-2011-6yu7cz.

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In this paper, observation on twin seedlings in Semecarpus kathalekanensis is reported. Out of 850 seeds germinated (from seven individuals), two seeds gave out twin seedlings. Further, the growth of twin seedlings with normal seedlings have been recorded and discussed here.

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Goyal, Neha, Kapil Gupta, and Nitin Kumar. "Multiclass Twin Support Vector Machine for plant species identification." Multimedia Tools and Applications 78, no. 19 (June 26, 2019): 27785–808. http://dx.doi.org/10.1007/s11042-019-7588-2.

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Matte, U., M. G. Le Roux, B. Bénichou, J. P. Moisan, and R. Giugliani. "Study on Possible Increase in Twinning Rate at a Small Village in South Brazil." Acta geneticae medicae et gemellologiae: twin research 45, no. 4 (October 1996): 431–37. http://dx.doi.org/10.1017/s0001566000000829.

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AbstractA high frequency of twin births has been observed in Linha São Pedro, a small settlement which belongs to the city of Cândido Godói, located 524 km Northwest from Porto Alegre, Rio Grande do Sul, Brazil, in an ethnically homogeneous population of German descent restricted to a small geographic region. From 1990 to 1994, the proportion of twin births in Linha São Pedro was 10%, significantly higher than the 1.8% rate for the state of Rio Grande do Sul as a whole. Genealogical analysis showed a high recurrence of multiple births within families, as well as a high level of inbreeding in the community. Zygosity data indicated that 9 of the 17 pairs of twins studied (53%) were dizygotic. No external environmental factors were detected that could be influencing the appearance of this characteristic. This preliminary investigation confirmed the presumed existence of a high twinning rate in the community. The high familial recurrence and the high inbreeding rate suggests the presence of genetic twinning factors. Complementary studies of twins that have yet to be evaluated and the search for additional risk factors, as well as linkage studies, should contribute to a further understanding of the biological factors related to twin births in the human species.

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W Stevenson, Andrew, and Geoff N Pain. "X-ray Diffraction Investigation of Epitaxial Layers of CdTe on Sapphire." Australian Journal of Physics 43, no. 6 (1990): 793. http://dx.doi.org/10.1071/ph900793.

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The anomalous scattering of X-rays has been used to determine the polarity of CdTe epitaxial layers on sapphire. The results for two samples are presented, one of (111) orientation ('A face'), the other of (III) orientation (,B face'). The (III) layer is twinned, the two twin species being related by a 180� rotation about the [1111 axis. The twin fraction shows considerable variation for different positions on this sample, and must be taken into account when analysing the integrated X-ray intensities, in order to get meaningful Bijvoet ratios. The polarities of the two twin species are found to be the same.

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Bütikofer, Aline, David N. Figlio, Krzysztof Karbownik, Christopher W. Kuzawa, and Kjell G. Salvanes. "Evidence that prenatal testosterone transfer from male twins reduces the fertility and socioeconomic success of their female co-twins." Proceedings of the National Academy of Sciences 116, no. 14 (March 18, 2019): 6749–53. http://dx.doi.org/10.1073/pnas.1812786116.

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During sensitive periods in utero, gonadal steroids help organize biological sex differences in humans and other mammals. In litter-bearing species, chromosomal females passively exposed to prenatal testosterone from male littermates exhibit altered physical and behavioral traits as adults. The consequences of such effects are less well understood in humans, but recent near-doubling of twinning rates in many countries since 1980, secondary to advanced maternal age and increased reliance on in vitro fertilization, means that an increasing subset of females in many populations may be exposed to prenatal testosterone from their male co-twin. Here we use data on all births in Norway (n= 728,842, including 13,800 twins) between 1967 and 1978 to show that females exposed in utero to a male co-twin have a decreased probability of graduating from high school (15.2%), completing college (3.9%), and being married (11.7%), and have lower fertility (5.8%) and life-cycle earnings (8.6%). These relationships remain unchanged among the subsets of 583 and 239 females whose male co-twin died during the first postnatal year and first 28 days of life, respectively, supporting the interpretation that they are due primarily to prenatal exposure rather than to postnatal socialization effects of being raised with a male sibling. Our findings provide empirical evidence, using objectively measured nation-level data, that human females exposed prenatally to a male co-twin experience long-term changes in marriage, fertility, and human capital. These findings support the hypothesis of in utero testosterone transfer between twins, which is likely affecting a small but growing subset of females worldwide.

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Gunaga, Rajesh, and R. Vasudeva. "Twin seedlings in Symplocos Kanarana Talb." Indian Journal of Forestry 34, no. 4 (December 1, 2011): 489–90. http://dx.doi.org/10.54207/bsmps1000-2011-0gzyfp.

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Symplocos kanarana Talbot (Family: Symplocaceae) is an evergreen tree species of the Western Ghats. During the nursery study, three twin seedlings of S. kanarana are recorded and it contributed 5% abnormality to the entire seedling lot.

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Brand, E., Y. Laenen, F. van Wijk, M. de Zoete, and B. Oldenburg. "OP10 IgA coating of intestinal microbiota is associated with inflammatory bowel disease in twin pairs discordant for inflammatory bowel disease." Journal of Crohn's and Colitis 14, Supplement_1 (January 2020): S010—S011. http://dx.doi.org/10.1093/ecco-jcc/jjz203.009.

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Abstract Background The pathogenesis of inflammatory bowel disease (IBD) is thought to result from an interplay between microbiota, the immune system and the environment in genetically susceptible hosts. Immunoglobulin A (IgA) produced by the immune system can be specifically directed against bacteria. The IgA-coating pattern of intestinal bacteria thus reflects interactions between the immune system and specific bacteria. Studying IBD in twins, concordant and discordant for IBD, reduces the impact of genetic predisposition and childhood exposures and therefore offers the unique opportunity to focus on other factors such as intestinal microbiota composition and immune-interactions in IBD. Methods Faecal samples from twin pairs discordant for Crohn’s disease (CD) or ulcerative colitis (UC) were collected. Employing fluorescence-activated cell sorting, IgA+ and IgA− bacteria from the intestinal microbiota were sorted. Subsequently, (1) the total, (2) IgA+ and (3) IgA− microbial composition was determined by 16S rRNA sequencing (IgA-SEQ). We estimated the relative IgA coating per bacterial species by dividing the abundance of that species in the IgA+ fraction over the abundance in the IgA- fraction, representing the IgA coating index. Linear discriminant analyses were performed with LefSE. Results We included 31 twin pairs (62 individuals) discordant for IBD (CD: 15, UC: 16). 15/32 twin pairs were monozygotic, 43/62 of participants were female, the median age was 47 years (interquartile range: 34–58.5). Of 31 participants with IBD, 7 had signs of active inflammation based on endoscopy, Harvey–Bradshaw index or short clinical colitis activity index. Differences (log-linear discriminant analysis score >3) in the microbial composition of IgA-coated bacteria were observed between CD patients and their twin-siblings not affected by IBD: Dorea formicigenerans (increased in IgA coating), Parabacteroides sp., Christensenellaceae sp., Clostridium sp. and Mollicutes RF39 sp. (decreased in IgA coating). In ulcerative colitis patients, an increase in IgA-coating was observed for Ruminococcus gnavus and Dorea formicigenerans, while Turicibacter sp., Barnesiellaceae sp. and an unclassified Clostridiales sp. were decreased in IgA-coating compared with their twin-siblings not affected by IBD. Conclusion In twins affected by IBD, the pattern of IgA-coated bacteria differs between IBD and non-IBD affected individuals. These data on immune-bacteria interactions could serve as a starting point for the elucidation of the immune-responses triggered by specific bacteria in IBD.

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Edmonds, Robert L., Ted B. Thomas, and Kathleen P. Maybury. "Tree population dynamics, growth, and mortality in old-growth forests in the western Olympic Mountains, Washington." Canadian Journal of Forest Research 23, no. 3 (March 1, 1993): 512–19. http://dx.doi.org/10.1139/x93-069.

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Tree population dynamics, growth, and mortality were determined in old-growth forested watersheds in the Hoh River valley, Olympic Peninsula, Washington: West Twin Creek (elevation 180–850 m) and Hoh Lake (elevation 1250–1525 m). Principal tree species at West Twin Creek are Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), Pacific silver fir (Abiesamabilis (Dougl.) Forb.), western red cedar (Thujaplicata D. Don), and Sitka spruce (Piceasitchensis (Bong.) Carr.). At Hoh Lake they are Pacific silver fir, mountain hemlock (Tsugamertensiana (Bong.) Carr.), and Alaska cedar (Chamaecyparisnootkatensis (D. Don) Spach). In 1985 stem densities for trees >5 cm DBH averaged 476 and 489 ha−1 in the upper and lower West Twin Creek watershed, respectively, and 508 ha−1 at Hoh Lake watershed. Stem densities at both sites declined 3–5% from 1985 to 1990. Western hemlock and Pacific silver fir were the dominant species at West Twin Creek and Hoh Lake, respectively. From 1985 to 1990 the annual mortality rate was 0.8% at West Twin Creek and 0.9% at Hoh Lake. Pacific silver fir had the highest mortality rate. No Douglas-fir or western red cedar trees died. The primary causes of mortality were as follows: suppression–unknown, diseases, insects, and windthrow. In 1985 basal areas were 77, 87, and 94 m2•ha−1 in the lower and upper West Twin Creek watershed and Hoh Lake watershed, respectively. There was a 5% increase and a 1% decrease in basal area from 1985 to 1990 in the lower and upper West Twin Creek watershed, respectively, and a 4% decrease at Hoh Lake. Western red cedar, Douglas-fir, and western hemlock increased in basal area, while the other species declined.

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Qiao, Maiju, Yingmin Zhou, Thomas Connor, Rengui Li, Dan Tang, Hemin Zhang, and Jianghong Ran. "Diagnosing Zygosity in Giant Panda Twins Using Short Tandem Repeats." Twin Research and Human Genetics 21, no. 6 (October 30, 2018): 527–32. http://dx.doi.org/10.1017/thg.2018.59.

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The giant panda, native to mountains of south-west China, is one of the world's rarest bear species and is subject to considerable conservation effort. In captivity, the proportion of twins accounts for 54% of the total number of births. To date, little is known about zygosity in panda populations — specifically, the proportion of monozygotic and dizygotic twins. In this study, we used 10 microsatellite markers for reliable zygosity testing, and the probability of monozygotic twins was 99.963% when all 10 markers were concordant. Out of 43 studied twin pairs, no MZ twins were found, indicating that there may be no identical panda twins (or the incidence is very low). We speculate that the fertilized eggs of giant pandas do not have the capability to split into two identical embryos, or that this ability is very poor, which is likely due to delayed implantation that is common in bear species. The results of this study deepen our understanding of giant panda breeding, yield insight into panda twins’ likely mechanism of formation, and reduce the uncertainty of individual identity in wild population surveys.

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Sapunov, V. B. "Ecological twin species and some obscure questions of hominidae evolutions." Human Evolution 10, no. 3 (July 1995): 193–98. http://dx.doi.org/10.1007/bf02438971.

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Kljakić, Duško, Miloš Z. Milosavljević, Milan Jovanović, Vesna Čolaković Popović, and Saša Raičević. "Serratia marcescens as a cause of unfavorable outcome in the twin pregnancy." Open Medicine 16, no. 1 (December 17, 2020): 81–86. http://dx.doi.org/10.1515/med-2021-0205.

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AbstractSeveral Serratia species are widely distributed in nature, but Serratia marcescens is the only species frequently isolated in hospitals. This pathogen is mainly responsible for nosocomial infection, mostly in immunocompromised hosts. A 26-year-old woman with a twin pregnancy, regularly controlled, was hospitalized at 24 + 5 weeks of gestation due to scant vaginal bleeding, lower abdominal pain, and body temperature up to 37.5°C. Gynecological examination revealed bleeding accompanied by dilatation of the cervix. The laboratory analyses revealed leukocytosis with elevated C-reactive protein (CRP). Treatment was initiated with intravenous antibiotic administration. After admission, fetal membranes spontaneously ruptured, and an extremely preterm dichorionic female twin birth occurred at 25 + 0 weeks of gestation. Both infants died two days after labor. Pathological and microbiological analyses revealed chorioamnionitis caused by S. marcescens. According to the antibiogram, antibiotic treatment was continued for the next 7 days. The examination of cervical and vaginal discharge samples was negative three days and two weeks after therapy. S. marcescens may cause spontaneous miscarriages and, in this important case, caused loss of discordant twins in an extremely preterm birth by an immunocompetent patient. Infection by S. marcescens cannot be excluded as a cause of discordant growth and needs to be confirmed by further research.

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Nguyen-Smith, R. T., A. Böddecker, L. Schücke, N. Bibinov, I. Korolov, Q.-Z. Zhang, T. Mussenbrock, P. Awakowicz, and J. Schulze. "μs and ns twin surface dielectric barrier discharges operated in air: from electrode erosion to plasma characteristics." Plasma Sources Science and Technology 31, no. 3 (March 1, 2022): 035008. http://dx.doi.org/10.1088/1361-6595/ac5452.

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Abstract Electrode erosion through continual long-timescale operation (60 min) of identical twin surface dielectric barrier discharges (twin SDBDs) powered either by a microsecond (μs) or a nanosecond timescale (ns) voltage source is investigated. The twin SDBDs are characterized using current–voltage measurements, optical emission spectroscopy, and phase integrated ICCD imaging. The temporally and spatially averaged gas temperature, consumed electric power, and effective discharge parameters (reduced electric field, and electron density) are measured. The μs twin SDBD is shown to operate in a filamentary mode while the ns twin SDBD is shown to operate in a more homogeneous mode (i.e. non filamentary). Despite a similarity of the effective discharge parameters in both the μs and ns twin SDBD, erosion of the nickel coated electrodes caused by operation of the twin SDBD differs strongly. Only the formation of a moderate number of nickel oxide species is observed on the surface of the ns twin SDBD electrodes. In contrast, the nickel coated electrodes are locally melted and considerably higher densities of oxides are observed around the eroded areas of the μs twin SDBD, due to the filamentary nature of the discharge.

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Kamimura, Yoshitaka. "Twin intromittent organs of Drosophila for traumatic insemination." Biology Letters 3, no. 4 (May 22, 2007): 401–4. http://dx.doi.org/10.1098/rsbl.2007.0192.

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In several animals, male genitalia create insemination wounds in areas outside the genital orifice of females. I report that such traumatic insemination (TI) occurs in the Drosophila bipectinata complex (Diptera: Drosophilidae) and illustrate a previously unknown evolutionary pathway for this behaviour. Flash fixation of mating pairs revealed the dual function of the paired claw-like basal processes, previously misidentified as a bifid aedeagus: (i) penetration of the female body wall near the genital orifice and (ii) sperm transfer into the genital tract through the wounds. Basal processes in closely related species ( Drosophila ananassae and Drosophila pallidosa ) also wounded females but did not transfer sperm; this represents a transitional state to TI as observed in the bipectinata complex. Copulatory wounding is suggested to occur in other allied species of the Drosophila melanogaster species group, including D. melanogaster . Ubiquitous sexual conflicts over mating may have led to the evolution of novel intromittent organs for insemination.

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Cozen, Wendy, Guoqin Yu, Mitchell Gail, Bharat N. Nathwani, Amie E. Hwang, Ann S. Hamilton, Thomas M. Mack, and James J. Goedert. "Fecal Microbiota Diversity in Survivors of Adolescent/Young Adult Hodgkin Lymphoma." Blood 120, no. 21 (November 16, 2012): 1533. http://dx.doi.org/10.1182/blood.v120.21.1533.1533.

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Abstract Abstract 1533 Survivors of adolescent/young adult Hodgkin lymphoma (AYAHL) report fewer exposures to infections during childhood compared to controls. They also have persistent genomic and functional aberrations in their lymphocytes that are partially attributable to chemotherapy or radiotherapy. Recent studies have shown that the gut microbiome can affect both the innate and adaptive immune response, and can suppress or exacerbate an inflammatory response. Given the central role of the gut microbiota in immune function, we investigated whether AYAHL survivors, who were members of 13 mono- and dizygotic twin pairs discordant for this disease, have differences in the diversity or phylogenetic configurations of their fecal microbiota compared to their unaffected co-twins. Twin pairs discordant for AYAHL are an ideal study population because they are at least partially matched on genetic and early life factors, both of which influence the composition of the gut microbiome. Pyrosequencing of bacterial 16S rRNA amplicons generated from single fecal samples obtained from each individual yielded 253,182 filtered and de-noised reads translated into species-level operational taxonomic units (OTUs). Standardized across individuals by random sampling, reads were assigned to 2513 OTUs to compare microbiome diversity and relative abundance of taxa. The number of OTU's was compared between twins using a paired student's t-test and a one-way analysis of variance was performed to determine whether such measures differed across twin pairs by comparing the measures between twins to those of randomly paired individuals. AYAHL survivors had less diverse fecal microbial communities compared to their unaffected co-twin controls by all measures of alpha diversity (Table 1). Measures that weighted the relative abundance of the bacteria were not statistically significantly different (Shannon Index, p= 0.270; Chao index, p= 0.066, PD Whole Tree Index, p= 0.051). However, when the unweighted number of unique OTUs was considered, the difference was significant (338 in cases vs. 369 in unaffected co-twin controls, p= 0.015). When the analysis was restricted to OTUs that were present at an abundance of > 0.1% in at least 2 of the 23 samples analyzed, the differences were attenuated, with only the PD Whole Tree index difference in diversity remaining marginally significant (p= 0.045). Only one bacterial taxon was associated with AYAHL, probably due to chance. Phylogenetic measurements indicated that the bacterial component of the microbiota of co-twins were more similar with respect to one another than unrelated individuals, although no differences by zygosity were observed. These results provide evidence that AYAHL survivors have reduced diversity of the gut microbiota, perhaps as a consequence the disease, its treatment, or a particularly hygienic environment. Table 1. Comparisons of alpha diversity measurements between Hodgkin lymphoma cases and co-twin controls. Measurements of Alpha Diversity Mean (Cases) Mean (Unaffected Co-twins) Mean Difference (Unaffected co-twin-case difference) P-value1 Initial analysis No. unique OTUs 338 369 31 0.015 Shannon index 5.6 5.8 0.2 0.27 Chao1 533 574 41 0.066 PD_whole tree 21.2 22.8 1.6 0.051 Conservative analysis No. unique OTUs 183 196 13 0.10 Shannon index 5.2 5.4 0.2 0.40 Chao1 230 237 7 0.47 PD_whole tree 13.7 14.6 0.9 0.045 1 P-value by paired t-tests. Disclosures: No relevant conflicts of interest to declare.

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Wanage, S., A. Mirgal, Rajesh Gunaga, A. Rane, S. Narkhede, and S. Bhave. "A note on twin and triplet seedlings in Madhuca Latifolia Roxb.: An important bio-fuel yielding tree species." Journal of Non-Timber Forest Products 17, no. 1 (March 1, 2010): 85–86. http://dx.doi.org/10.54207/bsmps2000-2010-5wm396.

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Madhuca latifolia is one of the economically important species, presently seeds of this species is used in biodiesel. In the present study we report twin and triplet seedlings in this species. Reporting of such variation in tree species is most important for future genetic improvement and conservation programmes.

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Molenaar, Peter C. M. "The Changing Role of the Embryo in Evolutionary Thought: Roots of Evo–DevoR. Amundson (2005). Cambridge, United Kingdom: Cambridge University Press." Twin Research and Human Genetics 11, no. 1 (February 1, 2008): 100–102. http://dx.doi.org/10.1375/twin.11.1.100.

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AbstractEvolutionary developmental biology (evo–devo) has become an established field of research, especially since the spectacular results obtained in the 1990s regarding cross-species molecular homologies of (Hox) genes acting early during embryogenesis in insects, vertebrates, and beyond. Amundson summarizes some of these results, which justify a central assertion of evo–devo, namely that one must understand how bodies are built in order to understand how the process of building bodies can be changed, that is, how evolution can occur. But Amundson's book is not about these discoveries, but about the history of evo–devo.

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GABRIEL, P., M. DIENSTBIER, P. SLADKÝ, and L. ČERNÝ. "Twin-angle turbidimeter for determination of some species of hazeforming particles." Kvasny Prumysl 40, no. 7 (July 1, 1994): 203–7. http://dx.doi.org/10.18832/kp1994015.

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Davies, Michael J. "Fetal programming: the perspective of single and twin pregnancies." Reproduction, Fertility and Development 17, no. 3 (2005): 379. http://dx.doi.org/10.1071/rd04101.

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Multiple pregnancy is associated with increased risk of adverse consequences for both mother and fetus(es), including increased rates of maternal hypertension and pre-eclampsia, spontaneous abortion, Caesarean delivery, low birthweight, birth prematurity, perinatal mortality, admission to neonatal intensive care and extended length of care, respiratory distress, cerebral palsy, developmental delay, contact with disability services and mortality to age 5 years. Premature birth, which affects 97% of triplets and 53.3% of twins in Australia, is not the sole factor involved. The rate of multiple pregnancy in Australia is 1.7%. This compares to 22.1% for pregnancies resulting from assisted reproduction technology (ART). As a result, 21.8% of babies born from ART are from a multiple pregnancy, in comparison to the USA where the majority of babies born from ART are from a multiple pregnancy. Additionally, the population rate of multiple births is rising due to the more frequent use of ART and continued multi-embryo transfers, which is operating against a background of rising implantation rates within ART clinics. Twins have been of interest from a programming perspective. However, analysis of associations between crude birthweight and subsequent metabolic risk factors or mortality in adulthood from chronic disease indicate that adaptations in pregnancy to support multi-fetal growth are not identical to fetal growth restriction in singleton pregnancies. Indeed, the process of ‘maternal constraint’ is incompletely understood and confounds such comparisons. From a programming perspective, it is a challenge to identify in twin pregnancies the transition from physiological adaptation to pathological growth restriction. Growth disparity between twins has been more illuminating of subtle adverse effects for the smaller of twin pairs in both blood pressure and insulin resistance in adulthood. Interestingly, these effects can be observed in both dizygotic and to a lesser degree in monozygotic twins, which indicates a role for both genetic and environmental factors in these measures. This suggests that, consistent with experimental studies in other species, the relationship between impaired growth in utero and chronic disease in later life is not simply mediated by a common genetic pathway.

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Calder, Dale R. "Associations between hydroid species assemblages and substrate types in the mangal at Twin Cays, Belize." Canadian Journal of Zoology 69, no. 8 (August 1, 1991): 2067–74. http://dx.doi.org/10.1139/z91-288.

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Hydroid species composition on various substrates in a mangrove ecosystem was investigated during the winter of 1987 at Twin Cays, Belize, Central America. Soft sediments, on which hydroids were either depauperate (peat) or not observed at all (silt, sand, mud), predominated in the study area. However, firm substrates, including submerged prop roots of red mangrove (Rhizophora mangle), turtle grass (Thalassia testudinum), benthic algae (Chlorophyta and Rhodophyta), floating algae (Turbinaria turbinata and Sargassum fluitans), epibenthic invertebrates (especially sponges, hydroids, molluscs, and crustaceans), wood, and rope, supported a moderately diverse hydroid fauna (48 species). More hydroid species (22) were found on mangrove prop roots than on any other substrate. Six substrate groups and 11 species groups were recognized in numerical analyses of hydroid–substrate frequency data. Constancy of species groups for substrate groups was mostly low or very low, reflecting the low frequency of occurrence of most hydroid species in collections from Twin Cays. Fidelity of some species groups for certain substrate groups was high, especially for those groups occurring on drifting algae and rope. Although most hydroid species were relatively facultative with respect to substrate, bottom type was an important factor influencing their distributions.

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Thach, Nguyen. "Amphidromus chrisabbasi, a new species (Gastropoda: Camaenidae) from Indonesia." Festivus 49, no. 3 (August 1, 2017): 206–9. http://dx.doi.org/10.54173/f493206.

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A new species of genus Amphidromus Albers, 1850 is described from the town of Soe, West Timor Island, Indonesia and compared to six other species of this genus: Amphidormus marieabbasae Thach, 2017, Amphidromus laevus laevus Müller, 1774, Amphidormus laevus janetabbasae Parsons, 2014, Amphidormus laevus nusleti Parsons, 2014, Amphidromus contrarius baaguiae Forcart, 1936 and Amphidromus reflexilabris Schepman, 1892. It is characterized by elongated aperture and twin (or coalescent) spiral lines, forming black or red-brown spiral bands on chalky white outer surface.

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Vishwanath, Sahana, A. N. Sringeswara, Syam Viswanath, and T. Rathore. "Occurrence of twin seedlings in Kingiodendron pinnatum (DC.) Harms (Leguminosae)- an endangered tree species of Western Ghats." Indian Journal of Forestry 35, no. 4 (December 1, 2012): 488–90. http://dx.doi.org/10.54207/bsmps1000-2012-1s204r.

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Kingiodendron pinnatum (DC.) Harms (Leguminosae) is an Endangered and endemic tree species of Western Ghats. The recorded twin seedlings contributed to 20% of the abnormality among the germinated seedlings.

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Catalano, Ralph A., Katherine B. Saxton, Alison Gemmill, and Terry Hartig. "Twinning in Norway Following the Oslo Massacre: Evidence of a ‘Bruce Effect’ in Humans." Twin Research and Human Genetics 19, no. 5 (July 25, 2016): 485–91. http://dx.doi.org/10.1017/thg.2016.58.

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Emerging theory and empirical work suggest that the ‘Bruce Effect’, or the increase in spontaneous abortion observed in non-human species when environments become threatening to offspring survival, may also appear in humans. We argue that, if it does, the effect would appear in the odds of twins among male and female live births. We test the hypothesis, implied by our argument, that the odds of a twin among male infants in Norway fell below, while those among females rose above, expected levels among birth cohorts in gestation in July 2011 when a deranged man murdered 77 Norwegians, including many youths. Results support the hypothesis and imply that the Bruce Effect operates in women to autonomically raise the standard of fetal fitness necessary to extend the gestation of twins. This circumstance has implications for using twins to estimate the relative contributions of genes and environment to human responses to exogenous stimuli.

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Schulze, Anja, and Mary E. Rice. "Sipunculan diversity at Twin Cays, Belize with a key to the species." Atoll Research Bulletin, no. 521 (2004): 1–9. http://dx.doi.org/10.5479/si.00775630.521.1-9.

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Place, G. T., S. C. Reberg-Horton, and D. L. Jordan. "Interaction of Cultivar, Planting Pattern, and Weed Management Tactics in Peanut." Weed Science 58, no. 4 (December 2010): 442–48. http://dx.doi.org/10.1614/ws-d-10-00012.1.

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Planting peanut in narrow rows for weed control has not been investigated in recently released Virginia market peanut cultivars. Research was conducted in North Carolina from 2007 to 2009 to determine the effect of cultivar, planting pattern, and level of weed management inputs on weed control, peanut yield, and estimated economic return. Experiments consisted of three levels of weed management (clethodim applied POST, cultivation and hand-removal of weeds, and clethodim and appropriate broadleaf herbicides applied POST), three levels of planting pattern (single rows spaced 91 cm apart, standard twin rows spaced 20 cm apart on 91-cm centers, and narrow twin rows consisting of twin rows spaced 20 cm apart on 46-cm centers), and two Virginia cultivars (‘NC 12C’ and ‘VA 98R’). Weed management affected common lambsquarters, common ragweed, eclipta, nodding spurge, pitted morningglory, Texas millet, and yellow nutsedge control, irrespective of cultivar or planting pattern. Cultivar and planting pattern had only minor effects on weed control and interactions of these treatment factors seldom occurred. Weed control achieved with cultivation plus hand-removal was similar to weed management observed with grass and broadleaf herbicide programs. Pod yield did not differ among treatments when broadleaf weeds were the dominant species but did differ when Texas millet was the most prevalent weed. The highest yield with conventional herbicide weed management was in standard twin and narrow twin row planting patterns, although no differences among planting patterns were noted when cultivation and hand-removal were the primary weed management tactics. Differences in estimated economic return were associated with weed species, and interactions of treatment factors varied by year for that parameter.

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Procacci, Alberto, Marianna Cafiero, Saurabh Sharma, Muhammad Mustafa Kamal, Axel Coussement, and Alessandro Parente. "Digital Twin for Experimental Data Fusion Applied to a Semi-Industrial Furnace Fed with H2-Rich Fuel Mixtures." Energies 16, no. 2 (January 5, 2023): 662. http://dx.doi.org/10.3390/en16020662.

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The objective of this work is to build a Digital Twin of a semi-industrial furnace using Gaussian Process Regression coupled with dimensionality reduction via Proper Orthogonal Decomposition. The Digital Twin is capable of integrating different sources of information, such as temperature, chemiluminescence intensity and species concentration at the outlet. The parameters selected to build the design space are the equivalence ratio and the benzene concentration in the fuel stream. The fuel consists of a H2/CH4/CO blend, doped with a progressive addition of C6H6. It is an H2-rich fuel mixture, representing a surrogate of a more complex Coke Oven Gas industrial mixture. The experimental measurements include the flame temperature distribution, measured on a 6×8 grid using an air-cooled suction pyrometer, spatially resolved chemiluminescence measurements of OH* and CH*, and the species concentration (i.e., NO, NO2, CO, H2O, CO2, O2) measured in the exhaust gases. The GPR-based Digital Twin approach has already been successfully applied on numerical datasets coming from CFD simulations. In this work, we demonstrate that the same approach can be applied on heterogeneous datasets, obtained from experimental measurements.

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Mashkou, Ya I., and H. S. Gajduchenko. "Cryptic species of the genus Microtus on the territory of Belarus: taxonomic position and distribution." Proceedings of the National Academy of Sciences of Belarus, Biological Series 66, no. 4 (November 10, 2021): 475–81. http://dx.doi.org/10.29235/1029-8940-2021-66-4-475-481.

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The paper presents the original data of the chromosomal and molecular-genetic (by PCR typing) analysis of cryptic species of the genus Microtus on the territory of Belarus. The aim of the study is to perform chromosomal labeling of common vole populations in various localities in Belarus to identify Microtus arvalis s. l. twin species in natural ecosystems. Based on the karyological analysis, 2 representatives of the cryptic group were identified in the study area: the Eastern European vole (2р = 54, NF = 56) and the common vole (2р = 46, NF = 86). Also, to confirm the species identity of the twin species, a molecular genetic analysis was performed by PCR typing. It was established that one studied individual from the cryptic group Microtus arvalis s. l. belongs to the species Microtus rossiaemeridionalis. A fragment of the cyt b mitochondrial gene was amplified in the size of 469 bp in the remaining individuals (n = 105), and a fragment of the cytochrome b mitochondrial gene in the size of 842 was amplified, which indicates that these representatives belong to the Microtus arvalis form “arvalis”. In conclusion, the results of the work done are summed up, and tasks are set for further research of cryptic species of the genus Microtus in Belarus.

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Lai, Mei I., Chad Garner, Jie Jiang, Nicholas Silver, Steve Best, Stephan Menzel, and Swee L. Thein. "A Twins Heritability Study on Alpha Hemoglobin Stabilizing Protein (AHSP) Expression Variability." Twin Research and Human Genetics 13, no. 6 (December 1, 2010): 567–72. http://dx.doi.org/10.1375/twin.13.6.567.

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Cytotoxic precipitation of free α-globin monomers and its production of reactive oxygen species cause red cell membrane damage that leads to anemia and eventually ineffective erythropoiesis in β-thalassemia. Alpha hemoglobin stabilizing protein (AHSP) was found to bind only to free α-globin monomers creating a stable and inert complex which remains soluble in the cytoplasm thus preventing harmful precipitations. Alpha hemoglobin stabilizing protein was shown to bind nascent α-globin monomers with transient strength before transferring α-globin to β-globin to form hemoglobin tetramer. A classical twin study would be beneficial to investigate the role of genetics and environment in the variation of alpha hemoglobin stabilizing protein expression as this knowledge will enable us to determine further investigations with regards to therapeutic interventions if alpha hemoglobin stabilizing protein is to be a therapeutic agent for β-thalassemia. This study investigates the heritability influence of alpha hemoglobin stabilizing protein expression and factors that may contribute to this. Results indicated that a major proportion of alpha hemoglobin stabilizing protein expression was influenced by genetic heritability (46%) withcis-acting factors accounting for 19% andtrans-acting factors at 27%.

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Gabrielian, E. Tz. "Fritillaria tunievii (Liliaceae), a new species from Armenia and North-East Anatolia." Novitates Systematicae Plantarum Vascularium, no. 49 (2018): 19–23. http://dx.doi.org/10.31111/novitates/2018.49.19.

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The new peculiar species Fritillaria tunievii Gabrielian with twin flowers is described from Urts mountain range in Yerevan fl oristic region of Armenia. Revision of herbarium collections of related species revealed this species to grow also in Aragats, Aparan and Darelegis floristic regions of Armenia, and even in North-East Anatolia. Description, holotype image, distinguishing features from F. hajastanica (Gabrielian) Gabrielian, F. caucasica Adams and F. assyriaca Baker, the map of distribution of the species and photos of plants are enclosed.

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Biswas, Lalitha, Raja Biswas, Christiane Nerz, Knut Ohlsen, Martin Schlag, Tina Schäfer, Tobias Lamkemeyer, et al. "Role of the Twin-Arginine Translocation Pathway in Staphylococcus." Journal of Bacteriology 191, no. 19 (July 24, 2009): 5921–29. http://dx.doi.org/10.1128/jb.00642-09.

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ABSTRACT In Staphylococcus, the twin-arginine translocation (Tat) pathway is present only in some species and is composed of TatA and TatC. The tatAC operon is associated with the fepABC operon, which encodes homologs to an iron-binding lipoprotein, an iron-dependent peroxidase (FepB), and a high-affinity iron permease. The FepB protein has a typical twin-arginine (RR) signal peptide. The tat and fep operons constitute an entity that is not present in all staphylococcal species. Our analysis was focused on Staphylococcus aureus and S. carnosus strains. Tat deletion mutants (ΔtatAC) were unable to export active FepB, indicating that this enzyme is a Tat substrate. When the RR signal sequence from FepB was fused to prolipase and protein A, their export became Tat dependent. Since no other protein with a Tat signal could be detected, the fepABC-tatAC genes comprise not only a genetic but also a functional unit. We demonstrated that FepABC drives iron import, and in a mouse kidney abscess model, the bacterial loads of ΔtatAC and Δtat-fep mutants were decreased. For the first time, we show that the Tat pathway in S. aureus is functional and serves to translocate the iron-dependent peroxidase FepB.

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Casser, Ellen, Steffen Israel, and Michele Boiani. "Multiplying embryos: experimental monozygotic polyembryony in mammals and its uses." International Journal of Developmental Biology 63, no. 3-4-5 (2019): 143–55. http://dx.doi.org/10.1387/ijdb.190016mb.

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Monozygotic (MZ) polyembryony is a strategy to increase the output of a single zygote, thereby producing more offspring from a limited number of oocytes. However, MZ twins and multiples (multiplets) of mammals occur rarely in nature, while their generation has been more successful experimentally. In this work, we review some of the methodological, biological and field aspects of experimental MZ polyembryony in mammals. First attempts of mechanical bisection of 2-cell stage rodent embryos provided a proof-of-principle for the survival and independent development of both blastomeres. Subsequently, experiments in other species, particularly sheep and bovine, allowed 2 methods of embryo multiplication to become routine: the separation or biopsy of blastomeres from cleavage-stage embryos and the bisection of morulae and blastocysts. We discuss how the preferable stage of bisection and the success rate can be species-specific. The scope that profited most from experimental MZ polyembryony is the production of additional copies of elite livestock individuals, the reduction of interindividual variation in test groups and the possibility of investigating discordant phenotypic traits in the same genomic background, for instance, comparing an affected twin with its healthy co-twin. By contrast, the original motivation for experimental polyembryony – efficiently generating more offspring out of the same zygote – has not been fulfilled yet. Although embryo splitting leads to an increase in quantity, there is a loss of embryo quality, thus, there is no real gain from artificially generated embryos (yet) in the field of medically assisted reproduction. In conclusion, mammalian zygotes have the regulative capacity to be polyembryonic, but this is not obligate.

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Hewitt, J. K., A. J. Stunkard, D. Carroll, J. Sims, and J. R. Turner. "A Twin Study Approach Towards Understanding Genetic Contributions to Body Size and Metabolic Rate." Acta geneticae medicae et gemellologiae: twin research 40, no. 2 (April 1991): 133–46. http://dx.doi.org/10.1017/s0001566000002567.

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AbstractThe genetic and environmental determinants of a brief assessment of metabolic rate at rest and under psychological stress were studied in 40 pairs of monozygotic and 40 pairs of dizygotic young adult male twins. Height, weight and age were employed as covariates. Univariate analyses showed a high heritability for height and weight and moderate heritability for metabolic rate. Classical twin analyses and multivariate genetic modeling indicated that genetic influences on resting metabolic rate were entirely explained by body weight: there was no independent genetic contribution to resting metabolic rate. Metabolic rate under psychological stress, on the other hand, showed a significant genetic effect. The exponent (3/4) in the power function relating body weight to resting metabolic rate was the same as that found in a wide variety of animal species, a value that has been proposed as defining a body weight set point. We speculate that an adult body weight set point is genetically transmitted. Independent genetic effects on resting metabolic rate would be observed only when the normal equilibrium between body weight and metabolic rate is unbalanced during development, aging or disease. The study illustrates the use of multivariate genetic analyses of twin data which may be readily applied to widely used metabolic rate assessments.

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Buglova, Lyubov V., and Olga S. Zhirova. "Peculiarities of microevolution processes in Trollius asiaticus in South Siberia Mountains." BIO Web of Conferences 24 (2020): 00016. http://dx.doi.org/10.1051/bioconf/20202400016.

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In the paper, we analyse the distribution of species and forms closely-related to Trollius asiaticus L. growing in the mountains of South Siberia between the Altai Mountain Country and Baikalia. The interrelationship between the endemic species and forms of high-mountains and parental lowland forms are adjacent-sympatric. We suppose the ways of disruptive selection to be of the same type, thus resulting in T. sajanensis and T. altaicus speciation, which are twin-species to each other. Between the parental and daughter species, there are interlayers of morphological forms being introgressive to both species. Key words: characters, populations, disruptive selection, introgression, speciation.

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Van Niel, Brigitta. "Unusual twin specimens of <i>Nannoconus abundans</i> (Calcareous Nannofossil, <i>Incertae Sedis</i>)." Journal of Micropalaeontology 14, no. 2 (October 1, 1995): 159–64. http://dx.doi.org/10.1144/jm.14.2.159.

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Abstract. Monospecific laminae of the species Nannoconus abundans (calcareous nannofossil, incertae sedis) were studied from the Munk Marl of North Jens-1, Danish Central Trough. These laminae contained unusual twin specimens which are considered to represent natural associations, rather than preservation artefacts.

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GEMEL, RICHARD, and VLADISLAV VERGILOV. "Nomenclatural-taxonomic notes on the genus Ablepharus Fitzinger, 1824 (Squamata: Scincidae)." Zootaxa 4858, no. 3 (October 1, 2020): 448–50. http://dx.doi.org/10.11646/zootaxa.4858.3.11.

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The two following notes concern two species of small skinks, genus Ablepharus: Lindberg’s Twin-striped Skink (Ablepharus lindbergi) and the Snake-eyed Skink (Ablepharus kitaibelii). Both species are small fossorial/semi-fossorial skinks with fused eyelids and a hidden lifestyle. A. kitaibelii is distributed disjunctly in several subspecies in Central and Southeastern Europe as well as in Western Turkey, A. lindbergi is distributed in Western Afghanistan (Uetz et al. 2020).

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da Rocha, Carlos Eduardo Falavigna. "Neocyclops (Protoneocyclops) ferrarii, a new species of cyclopid (Copepoda: Cyclopoida) from Belize, with remarks on the morphology of the genus Neocyclops." Bijdragen tot de Dierkunde 65, no. 1 (1995): 41–51. http://dx.doi.org/10.1163/26660644-06501004.

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Neocyclops (Protoneocyclops) ferrarii sp. n. is described from Candy’s Pond, Twin Cays, Belize. It is morphologically closest to N. (P.) wellsi Petkovski, 1986 from Mozambique and N. (P.) herbsti Petkovski, 1986 from the Red Sea.

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Snyder, Aleksandra, Adriana I. Vasil, Sheryl L. Zajdowicz, Zachary R. Wilson, and Michael L. Vasil. "Role of the Pseudomonas aeruginosa PlcH Tat Signal Peptide in Protein Secretion, Transcription, and Cross-Species Tat Secretion System Compatibility." Journal of Bacteriology 188, no. 5 (March 1, 2006): 1762–74. http://dx.doi.org/10.1128/jb.188.5.1762-1774.2006.

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ABSTRACT The secretion of PlcH and its homolog PlcN of Pseudomonas aeruginosa through the inner membrane depends upon a functional twin arginine translocase (Tat) system and a Tat signal sequence. Conserved twin arginine (Arg) residues within the Tat signal sequence consensus motif (S/TRRxFLK) are considered essential for the secretion of Tat substrates, but some exceptions (e.g., Lys and Arg) to the twin Arg residues in this motif have been noted. The roles of all three Arg residues within the PlcH RRRTFLK consensus motif were examined. Data are presented which indicate that Arg-9 and Arg-10 are essential for PlcH secretion across the inner membrane, but the mutation of Arg-8 (e.g., to Ala or Ser) had no observable effect on the localization of PlcH. In the signal sequence of PlcH and in all of its homologs in other bacteria, there are basic amino acid residues (Arg, Lys, and Gln) immediately adjacent to the signal peptidase cleavage site (Ala-X-Ala) that are not seen in Sec-dependent signal sequences. The mutation of these basic residues to Ala caused slightly decreased levels of extracellular PlcH, but normal localization was still observed. Deletion of the entire Tat signal sequence of PlcH not only resulted in the absence of detectable extracellular PlcH activity and protein but also caused a substantial decrease in the detectable level of plcH mRNA. Finally, data are presented which indicate that P. aeruginosa PlcH exhibits cross-species compatibility with the Escherichia coli Tat secretion machinery, but only when the E. coli Tat machinery is expressed in a P. aeruginosa host.

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Faust, Maria A., Mark W. Vandersea, Steven R. Kibler, Patricia A. Tester, and R. Wayne Litaker. "PROROCENTRUM LEVIS, A NEW BENTHIC SPECIES (DINOPHYCEAE) FROM A MANGROVE ISLAND, TWIN CAYS, BELIZE." Journal of Phycology 44, no. 1 (February 2008): 232–40. http://dx.doi.org/10.1111/j.1529-8817.2007.00450.x.

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Ault, James R. "In Vitro Propagation of Eucomis autumnalis, E. comosa, and E. zambesiaca by Twin-scaling." HortScience 30, no. 7 (December 1995): 1441–42. http://dx.doi.org/10.21273/hortsci.30.7.1441.

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Shoot formed in vitro from twin-scale explants of Eucomis autumnalis (Mill.) Chitt., E. comosa (Houtt.) Wehrh., and E. zambesiaca Bak. cultured on Murashige and Skoog (MS) basal medium containing 0.0, 4.4, 11.1, or 22.2 μm BA and 0.0 or 5.4 μm NAA. In all three species, shoot proliferation was obtained from single-shoot explants subcultured on medium supplemented with 4.4, 11.1, or 22.2 μm BA and 0.0 or 5.4 μm NAA. Shoots of all three species rooted readily on MS medium supplemented with 0.0, 2.7, 5.4, or 10.8 mm NAA. Overall rooting percentages were 95%, 98%, and 100% for E. autumnalis, E. comosa, and E. zambesiaca, respectively. Plant survival for rooted shoots of all three species was 100% following transfer to a 1 perlite: 1 peat (v/v) medium in the greenhouse. Chemical names used: 6-benzyladenine (BA); 1-naphthaleneacetic acid (NAA).

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Pratama, R. A., Maria F. V. Ruslau, Dessy R. Suryani, and Martha Loupatty. "Dynamics Twin Cannibalism of Two Predator and Two Prey System with Prey Defense." MATEC Web of Conferences 372 (2022): 02008. http://dx.doi.org/10.1051/matecconf/202237202008.

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The study discusses the condition of the existence of all non-negative equilibrium points. There are 9 realistic equilibrium points from the constructed model. A local stable condition is obtained, a point of equilibrium that is completely biologically feasible. The analytical method on the mathematically formed model is limited, so numerical simulation is also given to explore the model. Numerical simulation is intervened in a model that will show growth in trajectories. The tendency of trajectories in prey one and predator one species is relatively the same because the interactions that occur are intensive. Likewise, prey two and predator two occur, and the interactions that occur cause population growth grow to fluctuate. Differences occur in both types of species, namely predator-prey one and predator-prey two. In the one interaction group, growth tends to be more volatile and moves slowly towards the point of stability in population growth. Incidence is inversely proportional to the interaction of species two which tend to be faster towards the stability point. In general, the results of numerical simulations show that there is a pattern formation in the predator-prey system that grows sustainabley.

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BLASCO, FREDDIE A., GRECEBIO JONATHAN D. ALEJANDRO, DANILO N. TANDANG, MARIANITA B. VALES, and ROSARIO R. RUBITE. "Begonia amparoi (Begoniaceae, section Baryandra) a new species from Linungaw Twin Islands, Surigao del Sur, Mindanao, Philippines." Phytotaxa 549, no. 2 (June 8, 2022): 136–40. http://dx.doi.org/10.11646/phytotaxa.549.2.2.

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We describe Begonia amparoi, a new species of Begonia section Baryandra from Linungaw Twin Islands, Mindanao, Philippines. It grows on limestone and has a robust habit, with a thick rhizome and large leaves. Begonia amparoi is currently known only from the type locality in a coastal island forest of Tandag City, Province of Surigao del Sur. Based on IUCN red list criteria, B. amparoi is considered Vulnerable (VU).

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Journal articles on the topic 'Twin species'

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