The reproductive biology of lampreys is of special interest given the group has retained many developmental features reminiscent of the earliest vertebrates. Herein I report spawning behavior in the Least Brook Lamprey (Lampetra aepyptera) from southern Indiana and provide descriptions of its embryonic development. Nesting activities began in mid-March when water temperatures ranged from 10 to 12 C, as two or more individuals dug out shallow depressions in loose gravel immediately above riffles. Communal spawning groups (>10 individuals) subsequently formed at the nest sites when the water temperature rose above 12 C. Embryos generated from the gametes of spawning adults underwent gastrulation 72 h after fertilization, neurulation after 6 d, and hatched after 14 d. Prolarvae developed melanophores 19 d after fertilization, eyespots were visible by 20 d, and the velum began to beat 25 d after fertilization. Expulsion of yolk from the intestine and filter feeding occurred 26 d after fertilization. Embryonic development in L. aepyptera largely matches the embryonic stages established for the Sea Lamprey (Petromyzon marinus), with subtle differences in the sequence of specific developmental features. These descriptions clarify conflicting accounts of spawning activities for L. aepyptera and provide staging criteria for future investigations into its embryonic development.

These data are stable isotope data as well as basic physical data collected on larval lamprey reared in captivity and their food sources.

Studies of the voltage-gated sodium (Nav) channels of extant gnathostomes have made it possible to deduce that ancestral gnathostomes possessed four voltage-gated sodium channel genes derived from a single ancestral chordate gene following two rounds of genome duplication early in vertebrates. We investigated the Nav gene family in two species of lampreys (the Japanese lamprey, <i>Lethenteron japonicum</i> and sea lamprey, <i>Petromyzon marinus</i>) (jawless vertebrates—agnatha) and compared them with those of basal vertebrates to better understand the origin of Nav genes in vertebrates. We noted six Nav genes in both lamprey species but orthology with gnathostome (jawed vertebrate) channels was inconclusive. Surprisingly, the Nav2 gene, ubiquitously found in invertebrates and believed to have been lost in vertebrates, is present in lampreys, elephant shark (<i>Callorhinchus milii</i>) and coelacanth (<i>Latimeria chalumnae</i>). Despite repeated duplication of the Nav1 family in vertebrates, Nav2 is only in single copy in those vertebrates in which it is retained, and was independently lost in ray-finned fishes and tetrapods. Of the other five Nav channel genes, most were expressed in brain, one in brain and heart, and one exclusively in skeletal muscle. Invertebrates do not express Nav channel genes in muscle. Thus, early in the vertebrate lineage Nav channels began to diversify and different genes began to express in heart and muscle.

Various biological characteristics were compared between autumn and spring runs of Caspiomyzon wagneri migrating into the Shirood River, in an attempt to determine whether these were reproductively isolated. Two spawning runs of the same lamprey species in a single river are apparently unique to the Shirood. The autumn sample collected between 21 October and 1 November 2009 comprised 15 adults and the spring sample collected between 22 March and 18 April 2009 comprised 38 adults. While spawning was not witnessed, the significantly shorter mean total length of at least 40 cm in both males and females, and the significantly higher gonadosomatic index in females of the autumn run versus the spring run suggest that the former is closer to spawning than the latter. If one assumes a single spawning population per year in the river, the report by Nazari and Abdoli (2010) of recently spent individuals of Caspian lamprey collected in the Shirood River during April, would therefore imply that the spawning period is remarkably protracted. In order to test this hypothesis, the spawning sites need to be searched for higher upstream over the entire year, particularly in areas where suitable spawning substrate of gravel and sand occurs

The data set is six separate csv files. Four of which contain the quantity of DNA copy numbers and fluor used to analyze the DNA quantities collected from water samples from four separate portions of the study (adult SL field, adult SL lab, larval SL field, larval SL lab) and need to be in their own csv file. Also included is a csv with adult SL trapping data, a csv for larval SL shocking data, and a csv with the volume that was filtered for our DNA extractions.

Lampreys and hagfishes are the sole surviving representatives of the early agnathan (jawless) stage in vertebrate evolution, which has previously been regarded as the least encephalized group of all vertebrates. Very little is known, however, about the extent of interspecific variation in relative brain size in these fishes, as previous studies have focused on only a few species, even though lampreys exhibit a variety of life history traits. While some species are parasitic as adults, with varying feeding behaviors, others (nonparasitic species) do not feed after completing their macrophagous freshwater larval phase. In addition, some parasitic species remain in freshwater, while others undergo an anadromous migration. On the basis of data for postmetamorphic individuals representing approximately 40% of all lamprey species, with representatives from each of the three families, the aforementioned differences in life history traits are reflected in variations in relative brain size. Across all lampreys, brain mass increases with body mass with a scaling factor or slope (α) of 0.35, which is less than those calculated for different groups of gnathostomatous (jawed) vertebrates (α = 0.43-0.62). When parasitic and nonparasitic species are analyzed separately, with phylogeny taken into account, the scaling factors of both groups (parasitic α = 0.43, nonparasitic α = 0.45) approach those of gnathostomes. The relative brain size in fully grown adults of parasitic species is, however, less than that of the adults of nonparasitic species, paralleling differences between fully grown adults and recently metamorphosed individuals of anadromous species. The average degree of encephalization is found in anadromous parasitic lampreys and might thus represent the ancestral condition for extant lampreys. These results suggest that the degree of encephalization in lampreys varies according to both life history traits and phylogenetic relationships.

Lampreys belong to the superclass Cyclostomata and represent the most ancient group of vertebrates. Existing for over 360 million years, they are known as living fossils due to their many evolutionally conserved features. They are not only a keystone species for studying the origin and evolution of vertebrates, but also one of the best models for researching vertebrate embryonic development and organ differentiation. From the perspective of genetic information, the lamprey genome remains primitive compared with that of other higher vertebrates, and possesses abundant functional genes. Through scientific and technological progress, scientists have conducted in-depth studies on the nervous, endocrine, and immune systems of lampreys. Such research has significance for understanding and revealing the origin and evolution of vertebrates, and could contribute to a greater understanding of human diseases and treatments. This review presents the current progress and significance of lamprey research.

QPCR Primers: Forward and reverse primers used for qPCR analysis. (DOCX 112 kb)

The aims of this paper were to propose a modeling system of water UV disinfection, establish the influence of UV doses on the kinetics of disinfection, study UV-resistant strains of Pseudomonas aeruginosa, and improve the performances of this multipart process. The UV disinfection should inactivate pathogenic microorganisms and improve the hygienic quality of water. A comprehensive treatment in considering the mathematical aspect to model the UVc disinfection of water was achieved. A complete mathematical description of the inactivation kinetics is developed and showed two successive stages, a fast and a low one. Similarly, a mathematical model describing fluid flow and concentration of the microorganisms inside a UV reactor is developed. Modeling the kinetic and the UV lamp ray emission using some empirical approaches might increase the efficiency of UV disinfection and improve its performance. This study shows an improvement of the microbial inactivation rate of about 49% for the selected pathogenic resistant bacteria of P. aeruginosa (S3), and in considering perfectly mixed water flowing into the UV reactor. Key words: Disinfection, UV254, modeling, pathogenic microorganisms, performance.

cover: Mouth of a Petromyzon marinus lamprey, taken at Aquarium Finisterrae (Coruña, Galicia, Spain). The original has been rotated. Picture by Drow male (http://commons.wikimedia.org/wiki/User:Drow_male), Creative Commons license.

cover: Mouth of a Petromyzon marinus lamprey, taken at Aquarium Finisterrae (Coruña, Galicia, Spain). The original has been rotated. Picture by Drow male (http://commons.wikimedia.org/wiki/User:Drow_male), Creative Commons license.

This paper deals with the complex problem of modeling of water UVc disinfection, and it aimed to improve the performances of this multipart process. The UV disinfection should inactivate pathogenic microorganisms and improve the hygienic quality of water. A comprehensive treatment in considering the mathematical aspect to model the UVc disinfection of water was achieved. A complete mathematical description of the inactivation kinetics is developed and showed two successive stages, a fast and a low one. Similarly, a mathematical model describing fluid flow and concentration of the microorganisms inside a UV reactor is developed. Modeling the kinetic and the UV lamp ray emission using some empirical approaches might increase the efficiency of UV disinfection and improved its performance. This study showed an improvement of the microbial inactivation rate of about of 49% for the selected pathogenic resistant bacteria of Pseudomonas aeruginosa ATCC 15442, and in considering perfectly mixed water flowing into the UV reactor.

Dead lake trout (Salvelinus namaycush) killed by sea lamprey ( Petromyzon marinus) were collected from the bottom of Lake Ontario using bottom trawls. The number of dead lake trout per hectare could be predicted from the number of type A-1 sea lamprey marks observed on live fish in September gillnet surveys ( r 2 = 0.60, P 0.05) from those of live fish with A-1 marks in 5 of 6 years where compar- isons could be made. Compared with Lake Superior strain lake trout, Seneca Lake strain fish were only 0.41 times as likely to be attacked by sea lamprey and were less likely to die from an attack (both differences P 0,05) de celle observee chez les poissons vivants portant des cicatrices A-1, pour 5 des 6 annees ou une telle comparaison etait possible. La probabilite qu'un touladi de la souche du lac Seneca soit attaque par une lamproie equivalait a seulement 0,41 fois la probabilite qu'un tou- ladi de la souche du lac Superieur subisse le meme sort, et les attaques etaient moins souvent mortelles dans le premier cas ( P < 0,05 pour les deux differences). Les estimations prudentes du nombre de touladis tues par les lamproies marines dans le sud du lac Ontario entre octobre et la mi-novembre vont de 17 000 en 1988 a 121 000 en 1984. (Traduit par la Redaction)

This study is the first to provide direct physiological evidence that lamprey have a hypothalamus-pituitary-interrenal (HPI) axis that functions in a manner similar to that of more derived vertebrates. In teleost fishes, the hypothalamus produces corticotropin-releasing hormone (CRH), which stimulates the anterior pituitary to produce adrenocorticotropic hormone (ACTH), which in turn stimulates production of cortisol (F) from the interrenal cells of the head kidney. Although it has recently been shown that 11-deoxycortisol (S) is the functional corticosteroid in lamprey, no studies have yet determined its mechanism of regulation or site of production. This study demonstrated that 1) exposure to acute stress by air-exposure caused plasma S concentrations to increase, supporting its role as a stress hormone; 2) intraperitoneal injections of lamprey-CRH (0.1, 50, and 100 µg/kg) stimulated an increase in plasma S concentrations that was sensitive to dose, 3) intraperitoneal injection of four isoforms of lamprey-ACTH (each at 1.0 and 10 µg/kg) increased plasma S concentrations, although rates of production were low and varied by isoform between male and female subjects. Confirmation of the identity of 11-deoxycortisol was obtained by demonstrating that plasma extracts fractionated by high performance liquid chromatography (HPLC) had peaks of immunoreactive S that co-eluted with standard S using RIA. Finally, this study demonstrated that 4) lamprey mesonephric kidneys produced S in vitro when incubated in the presence of tritiated 17α-hydroxyprogesterone (17αP), as well as in the absence of any precursor hormones. The identity of the tritiated S produced in vitro was determined by co-elution with standard S on HPLC, and confirmed by co-migration with standard and acetylated S on thin-layer chromatography (TLC) after purification by HPLC. Together, these results provide supporting evidence that the stress response of lamprey, one of the oldest extant vertebrates, may be controlled through an axis similar to the hypothalamus-pituitary-interrenal (HPI) axis of teleost fishes, although additional studies in this area will be required for further confirmation.

Life history strategy has traditionally played an important role in the taxonomy of lampreys. In some cases, this was the basis for distinguishing socalled satellite species groups (1). Lamprey larvae within a satellite species group are morphologically identical; however, adult lampreys differ from one another in a number of species (primarily, the body length). It is believed that lampreys of some species migrate to large bodies of water (rivers, lakes, seas, and oceans) after metamorphosis, become parasites of bony fishes and begin to reproduce within 0.5-3 years, whereas lam� preys of other species remain in their native river, become mature within 6-10 months, and then die (1- 4). As a rule, a satellite species group comprises one parasitic anadromous species and several satellite resident species (nonparasitic or parasitic), which are assumed to have sympatrically originated from the first species (1, 4).

ISSN 0022-0930, Journal of Evolutionary Biochemistry and Physiology, 2011, Vol. 47, No. 1, pp. 97—99. © Pleiades Publishing, Ltd., 2010.Original Russian Text © I. S. Zubatkina, S. A. Konovalova, M. V. Savina, A. N. Nikiforov, 2011, published in Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, 2011, Vol. 47, No. 1, pp. 85—87.

Hagfish and lampreys are the only surviving fish without jaws. And they could solve an evolutionary mystery, finds Henry Nicholls.

Abstract This is a checklist of 51 pathogens of lamprey species found in Poland, including European river lamprey Lampetra fluviatilis (Linnaeus, 1758), European brook lamprey Lampetra planeri (Bloch, 1784), Ukrainian brook lamprey Eudontomyzon mariae (Berg, 1931), Danubian brook lamprey Eudontomyzon vladykovi Oliva and Zanandrea, 1959 and sea lamprey Petromyzon marinus Linnaeus, 1758.

A Closer Look at Lampreys for the Non-specialist

Modern look for ancient lamprey