Independently Evolving Species in Asexual Bdelloid Rotifers

Asexuals are an important test case for theories of why species exist. If asexual clades displayed the same pattern of discrete variation as sexual clades, this would challenge the traditional view that sex is necessary for diversification into species. However, critical evidence has been lacking: all putative examples have involved organisms with recent or ongoing histories of recombination and have relied on visual interpretation of patterns of genetic and phenotypic variation rather than on formal tests of alternative evolutionary scenarios. Here we show that a classic asexual clade, the bdelloid rotifers, has diversified into distinct evolutionary species. Intensive sampling of the genus Rotaria reveals the presence of well-separated genetic clusters indicative of independent evolution. Moreover, combined genetic and morphological analyses reveal divergent selection in feeding morphology, indicative of niche divergence. Some of the morphologically coherent groups experiencing divergent selection contain several genetic clusters, in common with findings of cryptic species in sexual organisms. Our results show that the main causes of speciation in sexual organisms, population isolation and divergent selection, have the same qualitative effects in an asexual clade. The study also demonstrates how combined molecular and morphological analyses can shed new light on the evolutionary nature of species

Reduction of EEG Theta Power and Changes in Motor Activity in Rats Treated with Ceftriaxone

The glutamate transporter GLT-1 is responsible for the largest proportion of total glutamate transport. Recently, it has been demonstrated that ceftriaxone (CEF) robustly increases GLT-1 expression. In addition, physiological studies have shown that GLT-1 up-regulation strongly affects synaptic plasticity, and leads to an impairment of the prepulse inhibition, a simple form of information processing, thus suggesting that GLT-1 over-expression may lead to dysfunctions of large populations of neurons. To test this possibility, we assessed whether CEF affects cortical electrical activity by using chronic electroencephalographic (EEG) recordings in male WKY rats. Spectral analysis showed that 8 days of CEF treatment resulted in a delayed reduction in EEG theta power (7–9 Hz) in both frontal and parietal derivations. This decrease peaked at day 10, i.e., 2 days after the end of treatment, and disappeared by day 16. In addition, we found that the same CEF treatment increased motor activity, especially when EEG changes are more prominent. Taken together, these data indicate that GLT-1 up-regulation, by modulating glutamatergic transmission, impairs the activity of widespread neural circuits. In addition, the increased motor activity and prepulse inhibition alterations previously described suggest that neural circuits involved in sensorimotor control are particularly sensitive to GLT-1 up-regulation

Abrochtha kingi Jr & Ricci & Melone & Fontaneto 2011, SP. NOV.

ABROCHTHA KINGI SP. NOV. Type material: Slide mounted holotype and ten paratypes, along with digital still and video photographs, deposited in the Academy of Natural Sciences, Philadelphia, accession numbers 2061 (holotype) and 2062 to 2071 (paratypes); DNA sequence of COI deposited in GenBank (accession number GU989444). All specimens were isolated from a clonal lab culture obtained from one individual named Shelf 1.3, collected from the type locality on 29 July 2002 by C. W. B. Type locality: Shelf Lake Number 3, Snowy Range, Wyoming, USA; altitude 3316 m, 41°22 ′ 43.2 ′′ N, 106°17 ′ 20.9 ′′ W. Etymology: The new species is dedicated to the lifelong studies of Charles Everett King, from Oregon State University, on ecology and genetics of rotifers. Differential diagnosis: No unambiguous discrimination is possible between this species and A. meselsoni so far, except from its COI sequence. Ramus length was significantly smaller than in A. meselsoni, but with a wide overlap; therefore, such difference in size is useless for taxonomic purposes. For A. kingi, we determined the mean ramus length from SEMs of the left and right ramus of 13 individuals. These data were compared to measurements of 40 trophi of A. meselsoni: 22 from the type clone (Angl2.7b), eight animals of clone Angl2.8, and ten from clone Angl1.1. Ramus length was significantly different amongst clones [analysis of variance (ANOVA) test: F 3,49 = 3.80, P = 0.015]; a post-hoc Tukey’s honestly significant difference (HSD) test gave a significant difference between the type clone of A. meselsoni and A. kingi (P = 0.002), but no significant differences amongst the different clones of A. meselsoni (P = 0.34 and 0.61). General morphology: The external morphology (Figs 5A, 6) completely overlaps with that of A. meselsoni. Refer to the previous description for its morphological features. Additionally, trophi shape and number of teeth are not distinguishable from A. meselsoni (Fig. 4C, D). 730 C. W. BIRKY ET AL. Measurements: Body measures overlap those of A. meselsoni and of A. kingi, but some animals reached larger size: total length, 360 Mm; trunk length, 210 Mm; trunk width, 110 Mm; head width, 60 Mm. The ramus length measured from SEM is 16.17 ± 0.63 (SD) Mm (N = 26). Distribution and ecology: This new species is known only from the type locality, Shelf Lake Number 3 in the Snowy Range of Wyoming. This is a small shallow lake in the Alpine Zone at an altitude of 3316 m that is filled with water from snowmelt and rain in summer, but covered by deep snow and at least partly frozen in winter. DNA barcoding: The sequence of partial COI mtDNA of animals collected from the same clonal laboratory culture Shelf1.3 has been deposited in GenBank with accession number GU989444.Published as part of Jr, C. William Birky, Ricci, Claudia, Melone, Giulio & Fontaneto, Diego, 2011, Integrating DNA and morphological taxonomy to describe diversity in poorly studied microscopic animals: new species of the genus Abrochtha Bryce, 1910 (Rotifera: Bdelloidea: Philodinavidae), pp. 723-734 in Zoological Journal of the Linnean Society 161 (4) on pages 729-730, DOI: 10.1111/j.1096-3642.2010.00674.x, http://zenodo.org/record/544018

Abrochtha sonneborni Jr & Ricci & Melone & Fontaneto 2011, SP. NOV.

<i>ABROCHTHA SONNEBORNI</i> SP. NOV. <p> <i>Type material:</i> Holotype deposited in the Academy of Natural Sciences, Philadelphia, accession number 2072; DNA sequence GenBank GU989443. The specimen was isolated from the clonal lab culture obtained from one single individual named Bird 3.X, collected by C. W. B. from the type locality on 26 July 2005.</p> <p>in the median part, where the apophyses are connected. Each uncus plate consists of two to three small minor teeth in the proximal part, 4/5 to 5/6 major teeth, and 12 to 15 distal minor teeth.</p> <p> <i>Measurements:</i> Total length, 170–260 Mm; trunk length, 100–170 Mm; trunk width, 30–50 Mm; head width, 30–45 Mm; foot, 25–40 Mm. Trophi, ramus length from SEM, 19.38 ± 0.66 (SD) Mm (<i>N</i> = 14).</p> <p> <i>Type locality:</i> Bird bath at 2641 N. Tomas Road, Tucson, Arizona, USA, altitude 652 m, 32°15 <i>′</i> 21.2 <i>′′</i> N, 111°2 <i>′</i> 36.7 <i>′′</i> W.</p> <p> <i>Etymology:</i> The new species is dedicated to the memory of Tracy Morton Sonneborn for his pioneering studies of the genetics of the ciliate <i>Paramecium</i>, including the discovery of cryptic biological species and a systematic revision of the genus. In addition to his work on <i>Paramecium</i>, he mentored two PhD students who did their thesis research on rotifers, one of whom is the first author of this paper.</p> <p> <i>Differential diagnosis:</i> A higher number of major teeth and a lower number of minor teeth on the unci plate together with a wider rami apophysis are the only morphological features to discriminate this species from the previous ones. Rami are also longer in this species.</p> <p> <i>General morphology:</i> The external morphology (Fig. 5B) completely overlaps with <i>A. meselsoni</i> and <i>A. kingi</i>. Refer to the previous descriptions for its morphological features. No SEM pictures are available for this species.</p> <p> The trophi of <i>A. sonneborni</i> are similar to those of <i>A. meselsoni</i> and <i>A. kingi</i> in morphology. Nevertheless, some clear differences are present (Fig. 7); the apophyses of the rami are less strong and much wider <i>Distribution and ecology:</i> This new species is known only from the type locality, a ceramic bird bath <i>c</i>. 0.05 m deep and 0.4 m diameter, intermittently filled with water, in the Sonoran Desert. It is an artificial analogue of temporary rock pools in the same region.</p> <p> <i>DNA barcoding:</i> The partial DNA sequence of the <i>COI</i> gene of animals collected from the laboratory culture of clone Bird3/X has been deposited in GenBank with accession number GU989443. Additional partial COI sequences from other specimens collected in the wild in the type locality, named Bird2.4 and Bird3.2, have been deposited in GenBank under accession numbers GU989441 and GU989442, respectively.</p>Published as part of <i>Jr, C. William Birky, Ricci, Claudia, Melone, Giulio & Fontaneto, Diego, 2011, Integrating DNA and morphological taxonomy to describe diversity in poorly studied microscopic animals: new species of the genus Abrochtha Bryce, 1910 (Rotifera: Bdelloidea: Philodinavidae), pp. 723-734 in Zoological Journal of the Linnean Society 161 (4)</i> on pages 730-731, DOI: 10.1111/j.1096-3642.2010.00674.x, <a href="http://zenodo.org/record/5440189">http://zenodo.org/record/5440189</a&gt

Abrochtha meselsoni Jr & Ricci & Melone & Fontaneto 2011, SP. NOV.

ABROCHTHA MESELSONI SP. NOV. Type material: The holotype and eight paratype specimens were isolated from a clonal lab culture obtained from one individual named Angl2.7b, collected from the type locality on 15 June 2005 by C. W. B. They are represented by slide mounts deposited in the Academy of Natural Sciences, Philadelphia, accession numbers ANSP 2052 (holotype) and 2053 to ANSP 2060 (paratypes), and by the COI sequence deposited in GenBank with accession number GU989432. Type locality: Angelfish Pool, on the east rim of Squirrel Canyon (Fish Creek), Virginia Dale, Coloado, USA, 40°57 ′ 21.6 ′′ N, 105°22 ′ 19.4 ′′ W, altitude 2190 m. Etymology: The new species is dedicated to the work of Matthew Stanley Meselson, from Harvard University, on the evolutionary genetics of bdelloid rotifers. Differential diagnosis: Morphologically, A. meselsoni resembles the other two species of the genus, Abrochtha carnivora Ricci, Melone & Walsh, 2001 and Abrochtha intermedia (de Beauchamp, 1909). Nevertheless, it may be easily distinguished from these by the wider rostrum and the higher number of major teeth on unci plate of trophi: 4/ 4 in A. meselsoni, 3/ 3 in A. intermedia, and 2/ 2 in A. carnivora. Moreover, A. carnivora is a much larger animal (> 500 Mm) and is the only known predatory bdelloid. General morphology: The three usual body regions of bdelloids can be distinguished: head, trunk, and foot (Figs 2, 3). The head is roundish and narrower than the trunk. Dorsally a single antenna is present, comprising two pseudosegments, with a terminal tuft of cilia. The apical part of the head bears the dorsal rostrum, which is wide and long. It is lined dorsally by a small bilobed lamella, with a sensory area present under the lamella. The rostrum is always clearly visible when the rotifer is creeping, and also when it is swimming, exceeding the trochi in length. The small trochi sit on small pedicels, well separated from each other, and appear as small auricles. The area between the trochi pedicels is covered by the upper lip, which, under the scanning electron microscope, appears flat on the head with square borders. The ventral part of the head is almost completely covered by a Y-shaped wide ciliated field, encircled laterally by a pair of small arched structures (cheeks). The mouth is ventral, at the bottom of the Y-shaped field. A series of ciliated structures is present between the mouth and the upper lip. Two red bright eyespots are present on the brain and are clearly visible when the animal is creeping, and when it is contracted in the tun shape. The trunk is divided in three major sections: the first one forms a broad neck connecting the head with the main part of the trunk. This is stout and cylindrical, offset from the neck and laterally and dorsally lined by a series of folds. No folds, either longitudinal or transversal, are visible on the ventral surface. This median part of the trunk is not narrower at its posterior end and is distinctly offset from the following part. The third part ends with the opening of the cloaca, and is much narrower than the two previous trunk sections; because of its shape, it may appear as the first segment of the foot. The majority of the internal space of the trunk is occupied by the stomach; this lies between paired vitellaria, each with eight large nuclei. The foot proper starts after the opening of the cloaca, and consists of four pseudosegments, the first two clearly visible and forming the longest part of the foot; the third one bears the spurs, and the last one bears four toes. The dorsal toes are smaller than the ventral ones. As in other bdelloids, pedal glands open on the tips of both spurs and toes. The trophi are ramate, as in other bdelloids, with paired symmetrical rami, unci, and manubria (Fig. 4A, B). Each ramus is provided with a strong apophysis close to the ventral end, widening in the median part of the trophi, where the apophyses are connected. The two rami articulate at the ventral tips and at the apophyses. Each ramus also has an elongated process on which unci plates lay. A series of small denticles, called scleropilia, are present on the interior margin of the elongated process of each ramus. Each uncus plate consists of a large number of teeth, with four small minor teeth in the proximal part, usually four sharp major teeth on each plate, but occasionally five major teeth on one uncus plate, and 16 to 19 distal minor teeth. Each major tooth is bordered by two smaller teeth variably fused to it. The arched manubria border the uncus plates; they are narrow bands, with one extremity at the base of the proximal minor teeth on the uncus and the other extremity at the junction with the tip of each ramus. Measurements: Total length, 150–300 Mm; trunk length, 80–180 Mm; trunk width, 50–80 Mm; head width, 30–45 Mm; rostrum, 10–15 Mm; antenna, 9–12 Mm; foot, 30–40 Mm; spur, 5–6 Mm. Trophi, ramus length from SEM, 16.93 ± 0.93 (SD) Mm (N = 42). Distribution and ecology: This new species is known from the type locality only. Angelfish Pool is a temporary pool in a depression in granite bedrock, approximately 0.02 m deep and 1.5 m wide, in open ponderosa pine, Douglas fir, and juniper forest in the Montane zone at the southern end of the Laramie Mountain range at an altitude of 2190 m. The pool is filled occasionally by snowmelt and/or rainwater. DNA barcoding: The partial COI sequence of Angl2.7b has been deposited in GenBank with accession number GU989432. Additional partial COI sequences from other specimens collected in the wild in the type locality, belonging to the same species have been deposited with GenBank accession numbers DQ078535 (Angl1.1) and GU989433 to GU989438 (Angl2.8, 3.6, 3.5, 3.4, 3.10, 3.11, respectively).Published as part of Jr, C. William Birky, Ricci, Claudia, Melone, Giulio & Fontaneto, Diego, 2011, Integrating DNA and morphological taxonomy to describe diversity in poorly studied microscopic animals: new species of the genus Abrochtha Bryce, 1910 (Rotifera: Bdelloidea: Philodinavidae), pp. 723-734 in Zoological Journal of the Linnean Society 161 (4) on pages 726-729, DOI: 10.1111/j.1096-3642.2010.00674.x, http://zenodo.org/record/544018

Biological Sulfur-Oxidizing Potential of Primary and Biological Sludge in a Tannery Wastewater Treatment Plant

Hydrogen sulfide (H2S) is one of the major tannery wastewater pollutants. Up today, chemical scrubbing is the most established technology for H2S removal in wastewater treatment plants. However, this procedure increases both the operating costs and the carbon footprint of the treatment. On the other hand, biological treatment is an emerging and sustainable technology for air pollution control. Our study focuses on the biological sulfur-oxidizing potential of autochthonous sludge of a plant treating tannery wastewater, located in Santa Croce (Tuscany, Italy). We propose a multidisciplinary approach to investigate two aspects: first, the composition of the microbial community both in the biological sludge and in the primary sludge and second, the sulfur-oxidizing potential of these native matrices. In order to do that, biological and primary sludge were used as inoculum in a reactor fed with sulfides. Then, traditional cultivation techniques were combined with several molecular approaches for analyzing the microbial community structure with a special focus on sulfur-oxidizing bacteria (SOB). Our study demonstrated that the use of different techniques was fundamental in order to detect the largest number of sulfur-oxidizing bacterial components; in particular, the detection of less represented components was guaranteed only by the performed multidisciplinary approach. Our study demonstrated the optimal performances of the reactor in selecting a sulfur-oxidizing biomass from autochthonous matrices. In addition, the importance of the primary sludge as inoculum for sulfuroxidizing reactors was proved