Findings of new and rare fish species in the coastal zone of the Crimea (the Black Sea)

Characteristics of seven Atlantic-Mediterranean fish species are provided. Of them, four (gobies—yellow-headed Gobius xanthocephalus and red-mouthed G. cruentatus, incognito blenny Parablennius incognitus, and greater pipefish Syngnathus acus) were either first found in the Black Sea coastal zone of the Crimea, or their findings were doubted, and three species (thin-lipped grey mullet Liza ramada, European barracuda Sphyraena sphyraena, and Black Sea salmon Salmo trutta labrax) are very rare. Over the last decade, the authors recorded 15 fish species; of them, seven Atlantic-Mediterranean species have dispersed along the Crimean coasts by now, one endemic of the far eastern seas (chameleon goby Tridentiger trigonocephalus) has naturalized in Sevastopol Bay, four invading species, freshwater by origin, permanently occur in the estuary zones of the peninsula; the remaining three species are known from single findings and apparently belong to the category of accidental fish. An increase in the species composition of ichthyofauna off the Black Sea coasts of the Crimea results from the on-going process of mediterranization—the invasion in the estuary of freshwater tolerant species at the expense of accidental species that penetrated here either independently or with ballast waters.     

A case for resurrecting lost species—review essay of Beth Shapiro’s, “How to Clone a Mammoth: The Science of De-extinction”

The title of Beth Shapiro’s ‘How to Clone a Mammoth’ contains an implicature: it suggests that it is indeed possible to clone a mammoth, to bring extinct species back from the dead. But in fact Shapiro both denies this is possible, and denies there would be good reason to do it even if it were possible. The de-extinct ‘mammoths’ she speaks of are merely ecological proxies for mammoths—elephants re-engineered for cold-tolerance by the addition to their genomes of a few mammoth genes. Shapiro’s denial that genuine species de-extinction is possible is based on her assumption that resurrected organisms would need to be perfectly indistinguishable from the creatures that died out. In this article I use the example of an extinct New Zealand wattlebird, the huia, to argue—contra Shapiro—that there are compelling reasons to resurrect certain species if it can be done. I then argue—again, contra Shapiro—that synthetically created organisms needn’t be perfectly indistinguishable from their genetic forebears in order for species de-extinction to be successful.     

Dietary preference and feeding ecology of Bloch’s gizzard shad, <Emphasis Type="Italic">Nematalosa nasus</Emphasis>

Dietary preference and feeding ecology of Nematalosa nasus (Bloch 1795) in Chilika lagoon, India, was investigated through analysis of prey items in the guts and that in the habitat. Of the 230 taxa identified from the habitat in plankton samples from the lagoon, thirty five taxa were recorded from the guts of the fish. Index of Relative Importance showed 80% of the food comprised of microplankton groups viz. Foraminifera (35.79%), Chlorophyceae (20.52%), Bacillariophyaceae (12.30%), Cyanophyaceae (6.53%), other plant matter (3.65%) and Euglenophyaceae (0.76%). The fish is a generalized feeder on microplankton, with specialization on foraminiferans and Chlorophyaceae in Chilika Lagoon. Diet composition varied significantly with seasons. Prey type selectivity showed, preference to Gyrosigma sp. (α_i—0.98, e_i—0.85), Synedra sp. (α_i—0.47, e_i—0.71), Tabellaria sp. (α_i—0.58, e_i—0.47) and Ulothrix sp. (α_i—0.06, e_i—0.34) during monsoon and post-monsoonseason. Ammoniabeccarii (α_i—0.77 e_i—0.98), Campylodiscus sp. (α_i—0.04, e_i—0.17) and Microspora sp. (α_i—0.18, e_i—0.76), were selected during pre-monsoon period, which is also the peak breeding period of the fish.     

Interactions Between the Circadian Clock and Heme Oxygenase in the Retina of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

The Drosophila retina has an autonomous peripheral circadian clock in which the expression of the gene encoding heme oxygenase (HO) is under circadian control with the ho mRNA peaking at the beginning of the day and in the middle of the night. The function of HO in the retina is unknown, but we observed that it regulates the circadian clock and protects photoreceptors against DNA damage. The decline in HO level increases and decreases the expression of the canonical clock genes period (per) and Clock (Clk), respectively. The opposite result was observed after increasing HO expression. Among three products of HO activity—carbon monoxide (CO), ferrous ions, and biliverdin—the latter has no effect on per and Clk expressions, but CO exerts the same effect as the increase of ho expression. This suggests that HO action on the clock is mediated by CO, which may affect Clk expression during the day and the level of per expression. While ho expression is not stimulated by nitric oxide (NO), NO has the same effect on the clock as HO, increasing Clk expression and decreasing the expression of per.     

Selection of optimal flocculant for effective harvesting of the fucoxanthin-rich marine microalga <Emphasis Type="Italic">Isochrysis galbana</Emphasis>

Flocculation harvesting of the fucoxanthin-rich marine microalga Isochrysis galbana has received little attention. Therefore, we attempted to screen for an optimal chemical flocculant and optimize flocculation conditions from five chemical flocculants—ferric chloride (FC), aluminum sulfate (AS), polyaluminum chloride (PAC), aluminum potassium sulfate (APS), and zinc sulfate (ZS)—for effective flocculation of I. galbana. The growth rate, photosynthetic performance, and fucoxanthin content were determined in re-suspended flocculated algal cells and in the flocculation supernatant cultured algal cells. The results showed that high growth rate and fucoxanthin accumulation were observed when FC was used as the flocculant in I. galbana cultures, which indicated that FC may cause less harm to I. galbana than the other aluminum-based flocculants. Furthermore, satisfactory flocculation efficiency was also observed when FC was used to flocculate I. galbana, and the FC dosage was less than that required for flocculation of I. galbana using PAC, APS, and AS. Thus, we selected FC as the optimal flocculant for harvesting I. galbana based on its flocculation efficiency together with algal physiological performance, growth rate, and fucoxanthin content.     

A study of the intestinal microbiomes of the Lake Baikal oilfishes (Cottoidei,Comephoridae)

A comparative analysis of the intestinal microbiomes of some representatives of the Lake Baikal endemic family Comephoridae—the big oilfish Comephorus baicalensis (Pallas, 1776) and the little oilfish C. dybowski (Korotneff, 1904)—has been performed for the first time. The phylotype Akkermansia (phylum Verrucomicrobia) was detected in the C. dybowski microbiome, while Alistipes, Bacteroides, Chryseobacterium, Prevotella (Bacteroidetes), and Peptoniphilus (Firmicutes), were found in the C. baicalensis microbiome. Their presence in the intestine is associated with an elevated lipid uptake or an increase in the human and animal body weight. It is hypothesized that these microorganisms are involved in the lipid metabolism of the oilfish and determine their morphophysiological adaptations to pelagic life.     

Activities of Adenylate Cyclase and Changes in cAMP Concentration in Root Cells of Pea Seedlings Infected with Mutualists and Phytopathogens

Work was carried out on pea (Pisum sativum L.) seedling roots to assess the attachment of the nitrogen-fixing symbiotic bacteria Rhizobium leguminosarum bv. vicea (Rlv) and the bacterial phytopathogens—specific Pseudomonas syringae pv. pisi (Psp) and nonspecific Clavibacter michiganensis ssp. sepedonicus (Cms). Different root zones were examined: (I) the meristem, 2 mm from the root tip; (II) the root hair-free zone, 27 mm; (III) the zone of root hair anlages, 712 mm; (IV) the young root hair zone, 1217 mm; and (V) the zone of root hair that completed the growth, 1722 mm. It was found earlier that the zones differed in their susceptibility to Rlv. In the present work, reactions of particular components of the adenylate cyclase signaling system (ACSS) were estimated, i.e., concentration of cAMP and activities of transmembrane adenylate cyclase (tAC) and soluble adenylate cyclase (sAC) in these zones after different times post inoculation (5, 15, 120, and 360 min). It was revealed that the degree of activation of particular components of ACSS did not depend on the sorption rate of differently specialized bacteria. Upon contact with Rlv, the character of changes in tAC and sAC activities was almost the same in different root zones and resembled the dynamics of the cAMP content. Inoculation with Psp changed the cAMP level similarly to that with Rlv, but the dynamics of tAC and sAC was opposite to each other in most cases. Inoculation with Cms, in spite of the absence of its attachment, elevated the cAMP content and activated tAC and sAC. It is suggested that the above-mentioned changes in ACSS is associated with exometabolites of Rlv, Psp, and Cms, which activate the PAMP-induced immunity of the pea seedling cells. The uniform dynamics of cAMP in different root zones upon the exposure to Rlv and Psp seems to reflect the specific reaction and, presumably, fulfills different functions—regulatory with Rlv and defensive with Psp. Upon short-term contact with Cms, the cAMP dynamics in the same root zones displayed a nonspecific character that might be related to the rate of adsorption of exopolysaccharides by the root hair. The systemic response of ACSS was observed in the hypocotyls of the seedlings exposed to any of the three organisms.     

The “<Emphasis Type="Italic">inoceramus</Emphasis> limpet”<Emphasis Type="Italic">Gigantocapulus problematicus</Emphasis> (<Emphasis Type="SmallCaps">Nagao &; Otatume</Emphasis>, 1938) in New Zealand (Late Cretaceous Gastropoda or Monoplacophora,Gigantocapulidae n. fam.)

Limpets up to at least 200 mm long occur widely in New Zealand early Haumurian (Campanian) rocks. Three specimens are in life position, attached to articulated specimens ofIsognomon. The limpet has several unique characters — an apparently anterior marginal apex (all gastropod limpets have a central or posterior apex), an enormously thickened apical area, and a tongue-like projection, with a gape at each side, below the margin at the anterior — demonstrating that it belongs inGigantocapulus Hayami &; Kanie. The low shape, weak sculpture, and marginal apex indicate that it belongs inG. problematicus (Nagao &; Otatume), previously reponed only from Japan and Kamchatka. New Zealand material supports previous interpretations that the apex was anterior, and thatGigantocapulus was an epiparasite or, more probably, a filter feeder living sedentarily on bivalves. The shell is, uniquely, composed of calcite in multiple complex crossed-lamellar layers, very different from the aragonite shell with inner nacreous and outer prismatic layers of both early Palaeozoic and present-day tergomyans. Nevertheless, as the anteriori?) tongue-like projection, thickening and gapes closely resemble those of early Palaeozoic tergomyans, no other limpet-shaped molluscs are known with an anterior apex, and not all modem monoplacophorans are minute (Neopilina reaches at least 40 mm long), a position in Monoplacophora (= Tergomya) remains a possibility. However,G. giganteus (Schmidt) has a subcentral apex and is clearly cyclomyan rather than tergomyan.Gigantocapulus is probably a vanikoroidean gastropod, but could also be a tergomyan, a helcionelloidan, or a member of another, now extinct group of gastropods. Gigantocapulidae n. fam. is proposed.     

The State of Ethnoprimatology: Its Use and Potential in Today’s Primate Research

The human–primate interface is an increasingly relevant theme in primatological research. To understand the extent of ethoprimatological studies in contemporary primatology, we explored 7 years of primatological literature through a systematic review. We reviewed original research papers published in the American Journal of Primatology, the International Journal of Primatology, Primates, and Folia Primatologica between January 2010 and December 2016 for the presence of 14 search terms relevant to the ethnoprimatological approach. We sorted research papers into topical categories to identify trends in the recent primatological literature. Of the 1551 papers that met the criteria for inclusion in this review, 12 papers (0.8%) self-identified as an ethnoprimatological study by using the term in the title or keywords, and only 17 papers (1.1%) used the term anywhere in their text. However, the presence of other relevant keywords—anthropogenic (16.3%), crop (9.1%), disturbance (18.7%), conflict (6.2%), human–nonhuman (0.5%), human–primate (1.0%), interface (1.5%), perception (2.5%), culture (2.6%), ethnography (0.1%), trade (6.8%), provision (16.1%), and tourism (4.6%)—in a variety of research papers suggests that the human–primate dimension is salient for many, if not most, areas of primatological interest. The ethnoprimatological approach is relevant to every research trend we identified in today’s primatology. We highlight existing literature that exemplifies ethnoprimatological engagement and present potential research questions in each area, demonstrating that primatology as a whole would benefit from greater attention to the human dimension.     

Biochemical evidence bearing on the domestication of<Emphasis Type="Italic">Phaseolus</Emphasis> (Fabaceae) beans

The genusPhaseolus (Fabaceae) consists of some 50 species, all of which are distributed in the Americas. Four of these contain cultigens.P. vulgaris (common bean),P. lunatus (lima bean),P. acutifolius (tepary bean),P. coccineus subsp.coccineus (runner bean); andP. coccineus subsp.polyanthus (no English vernacular name). Biochemical markers—phaseolin seed storage protein and isozymes—have provided new evidence on the organization of the first three species. Domestication has possibly caused a strong reduction in genetic diversity inP. vulgaris andP. acutifolius. BothP. vulgaris andP. lunatus cultivars result from at least two independent domestications, in Mesoamerica and in the Andes. These two species consist of two gene pools, each of which includes wild ancestors and their respective cultivated descendants. Our findings suggest the need for additional emphasis on genetic conservation of wild ancestors and their use in breeding programs and for a comparison of inter-gene pool vs. intra-gene pool crosses in breeding programs.     

A historical perspective on the engineering ideologies of sustainability: the case of SLCA

Purpose

The 1990s produced two distinct engineering ideologies of sustainability—one emphasizing engineering innovation and the other emphasizing socio-cultural change. The technological change ideology of sustainability refers to engineering reform controlled and directed by engineers themselves—in other words, technological practices can be improved through the application of expertise. The technopolitics’ ideology of sustainability is about engineering challenge; it places more emphasis on the devolution of expertise from the existing model of engineering and society, and it questions the dominant values of engineering practice. In this article, I present a historico-philosophical perspective on the development of social life cycle assessment (SLCA) to highlight how the dialectic between sustainability and engineering has been defined largely by the ideology of technological change.

Methods

I provide original historical evidence regarding the roles of key actors and institutions in fitting the life cycle perspective and corporate social responsibility (CSR) into sustainable development. Primary data for this chapter is based on archival materials as well as on 30, in depth, semi-structured interviews with North American and European LCA and SLCA experts. Other primary data were collected from participant observation in SLCA webinars and workshops.

Results and discussion

Technology is at the heart of SLCA—it is a shared faith in technology as the solution. At the same time, there is growing appreciation amongst SLCA proponents that such technology must be construed more critically. Although it remains a subaltern current within LCA, SLCA is evidence of how technological change and technopolitics are starting to converge and influence each other—a probe toward a more reflective form of engineering discourse and toward the formation of a new hybrid sustainability ideology.

Conclusions

SLCA, I argue in this article, is an ideological hybrid where there are many spots of dissent and disagreement but also some surprising fundamental alignments between those who see engineering as techniques and those who believe that engineering needs to be socially and politically contextualized. Yet, even as the concepts of sustainable development, CSR, and LCA provide the intellectual and institutional mold within which SLCA becomes conceivable, these concepts may also obscure the historicity of sustainability engineering.

     

A redescription of some poorly known Rotliegend arachnids from the Lower Permian (Asselian) of the Ilfeld and Thuringian Forest Basins, Germany

Two poorly known trigonotarbids (Arachnida: Trigonotarbida),Eophrynus schärft Scharf, 1924 andEophrynus ilfeldicus Scharf, 1924 from the Lower Permian (Asselian) Ilfeld Basin in the Harz Region of Germany are redescribed. The latter is transferred to the genusAphantomartus Pocock, 1911. The former resembles members of Lissomartidae, but given its incompleteness it is assigned here to Trigonotarbida incertae sedis. A phalangiotarbid (Arachnida: Phalangiotarbida) from Ilfeld described asOpiliotarbus elongatus (Scudder, 1890) represents the youngest record of this group. With respect to the genusOpiliotarbus Pocock, 1910,Architarbus hoffmanni Guthörl, 1934 — one of three names erected for a lost specimen from the Upper Carboniferous of the Saar region of Germany — represents the senior synonym ofOpiliotarbus kliveri Waterlot, 1934 andGoniotarbus sararm Guthörl, 1965. The Lower Permian fossilRhabdotarachnoides simoni Haupt, 1957 from the Rotliegend of the Thuringian Forest Basin, Germany was described as an arachnid and tentatively referred to Opiliones. Since it is identified here as a coalified plant remain, this species is regarded as nomen dubium.     

Alginate biosynthesis by <Emphasis Type="Italic">Azotobacter</Emphasis> bacteria

The ability of representatives of various species of the bacterial genus Azotobacter (A. chroococcum 7B, A. chroococcum 12B, A. chroococcum 12BS, A. agile 12, A. indicum 8, A. vinelandii 17, and A. vinelandii 5B) to alginate synthesis has been studied. It has been shown that all tested bacterial strains have this ability to different extents. Capsular alginate comprises from 2.6 to 32% of the total amount of synthesized alginate in various bacterial species. Strains that are able to active synthesis of alginate have been selected; the effect of the medium composition on their biosynthesis has been studied. The optimal conditions for alginate synthesis by the A. chroococcum 12BS producer strain include the presence of mannitol (40 g/L), yeast extract (1%), and low concentration of phosphates (KH₂PO₄—0.008 g/L, K₂HPO₄—0.032 g/L) in the medium; alginate production under these conditions is 4.5 g/L. The effect of aeration on polymer biosynthesis has been revealed: an increase in aeration causes an increase in alginate synthesis, while its decrease promotes the synthesis of poly-3-hydroxybutirate. It has been shown by IR spectroscopy that alginates obtained under various conditions of cultivation contain different ratios of residues of mannuronic and guluronic acids (M/G from 70/30 to 80/20) in the polymer chain and also differ in the amount of acetyl groups (from 10 to 25%) in the polyme structure.     

Cytogenetic evidences on the evolutionary relationships between the tetraploids of the section <Emphasis Type="Italic">Rhizomatosae</Emphasis> and related diploid species (<Emphasis Type="Italic">Arachis</Emphasis>, Leguminosae)

Rhizomatosae is a taxonomic section of the South American genus Arachis, whose diagnostic character is the presence of rhizomes in all its species. This section is of particular evolutionary interest because it has three polyploid (A. pseudovillosa, A. nitida and A. glabrata, 2n?=?4x?=?40) and only one diploid (A. burkartii, 2n?=?2x?=?20) species. The phylogenetic relationships of these species as well as the polyploidy nature and the origin of the tetraploids are still controversial. The present study provides an exhaustive analysis of the karyotypes of all rhizomatous species and six closely related diploid species of the sections Erectoides and Procumbentes by cytogenetic mapping of DAPI/CMA heterochromatin bands and 5S and 18–26S rDNA loci. Chromosome banding showed variation in the DAPI heterochromatin distribution pattern, which, together with the number and distribution of rDNA loci, allowed the characterization of all species studied here. The bulk of chromosomal markers suggest that the three rhizomatous tetraploid species constitute a natural group and may have at least one common diploid ancestor. The cytogenetic data of the diploid species analyzed evidenced that the only rhizomatous diploid species—A. burkartii—has a karyotype pattern different from those of the rhizomatous tetraploids, showing that it is not likely the genome donor of the tetraploids and the non-monophyletic nature of the section Rhizomatosae. Thus, the tetraploid species should be excluded from the R genome, which should remain exclusively for A. burkartii. Instead, the karyotype features of these tetraploids are compatible with those of different species of the sections Erectoides and Procumbentes (E genome species), suggesting the hypothesis of multiple origins of these tetraploids. In addition, the polyploid nature and the group of diploid species closer to the tetraploids are discussed.     

Spreading and mechanisms of antimicrobial resistance in microorganisms,producing beta-lactamases. Molecular mechanisms of resistance to beta-lactam antibiotics of <Emphasis Type="Italic">Klebsiella</Emphasis> spp. strains,isolated in cases of nosocomial infections

Antibiotic sensitivity has been investigated in nosocomial bacterial Klebsiella spp. strains isolated from patients treated in 30 hospitals of 15 Russian regions. Among Klebsiella strains (n = 212) studied the following species were found: Klebsiella pneumoniae ss. pneumoniae—182 (85.8%), Klebsiella pneumoniae ss. ozaenae—1 (0.5%), Klebsiella oxytoca—29 (13.7%) strains. Their sensitivity to antibacterial preparations was estimated by the method of serial dilutions in microvolume (the microdilution method). Carbapenems (imipenem and meropenem) exhibited the highest antibacterial activity against the strains studied. Among third generation cephalosporins the lowest MIC (Minimum inhibitory concentration) were found in the inhibitor protected preparations: ceftazidime/clavulanic acid (MIC₅₀ of 0.25 μg/ml; MIC₉₀ of 64 μg/ml) and cefoperazone/sulbactam (MIC₅₀ of 16 μg/ml; MIC₉₀ of 64 μg/ml). Using the PCR method the detection of class A betalactamases genes (TEM, SHV, CTX) was carried out in 42 strains of Klebsiella pneumoniae ss. pneumoniae. TEM type beta-lactamases were found alone or in various combinations in 16 (38.1%) strains, SHV—in 29 (69%), and CTX—in 27 (64.3%). Combinations of 2 and 3 different resistance determinants were detected in 23.8 and 26.2% of strains, respectively. Screening of carbapenem-resistant Klebsiella strains for production of class B metallo-beta-lactamases did not reveal nosocomial strains with phenotypically documented production of these enzymes.     

Refining the late Silurian sea-level history of the Prague Syncline—a case study based on the Přídolí GSSP (Czech Republic)

A 50-m-thick section in the Po?áry quarry, Prague Syncline (Czech Republic) spanning the upper Silurian (uppermost Ludlow and P?ídolí) to the lowermost Devonian (Lochkovian) has been studied using sedimentological and physical stratigraphical (gamma-ray spectrometry) methods combined with conodont biostratigraphy. Conodont data demonstrate the presence of local conodont biozones: “Ozarkodina” crispa (uppermost Ludlow)—Zieglerodina zellmeri (base of P?ídolí)—Zieglerodina ivochlupaci—Delotaxis detorta—“Ozarkodina” eosteinhornensis s.s.—Zieglerodina klonkensis—Icriodus hesperius-optima (lowermost Lochkovian). The studied section represents a transgressive–regressive facies succession characterized by a transition from distal calciturbidites deposited in a distally steepened carbonate platform during transgression and sea-level highstand (crispa to lower ivochlupaci zones) to mixed calciturbidites/coarse-grained bioclastic limestones (falling-stage systems tract, upper ivochlupaci to lower klonkensis zones). The upper part of the succession consists of bioclastic limestones corresponding to a subtidal setting between storm-wave and fair-weather wave base (lowstand systems tract in upper klonkensis and hesperius-optima zones). This interpretation corresponds to the late Silurian global sea-level pattern as recorded in other regions. Thus the depositional system is interpreted as mostly driven by eustasy with short-lived periods of influence from local tectonics.     

Cell cycle accumulation of the proliferating cell nuclear antigen PCN-1 transitions from continuous in the adult germline to intermittent in the early embryo of <Emphasis Type="Italic">C. elegans</Emphasis>

Background

The proliferating cell nuclear antigen (PCNA or PCN-1 in C. elegans), an essential processivity factor for DNA polymerase δ, has been widely used as a marker of S-phase. In C. elegans early embryos, PCN-1 accumulation is cyclic, localizing to the nucleus during S-phase and the cytoplasm during the rest of the cell cycle. The C. elegans larval and adult germline is an important model systems for studying cell cycle regulation, and it was observed that the cell cycle regulator cyclin E (CYE-1 in C. elegans) displays a non-cyclic, continuous accumulation pattern in this tissue. The accumulation pattern of PCN-1 has not been well defined in the larval and adult germline, and the objective of this study was to determine if the accumulation pattern is cyclic, as in other cells and organisms, or continuous, similar to cyclin E.

Results

To study the larval and adult germline accumulation of PCN-1 expressed from its native locus, we used CRISPR/Cas9 technology to engineer a novel allele of pcn-1 that encodes an epitope-tagged protein. S-phase nuclei were labeled using EdU nucleotide incorporation, and FLAG::PCN-1 was detected by antibody staining. All progenitor zone nuclei, including those that were not in S-phase (as they were negative for EdU staining) showed PCN-1 accumulation, indicating that PCN-1 accumulated during all cell cycle phases in the germline progenitor zone. The same result was observed with a GFP::PCN-1 fusion protein expressed from a transgene. pcn-1 loss-of-function mutations were analyzed, and pcn-1 was necessary for robust fertility and embryonic development.

Conclusions

In the C. elegans early embryo as well as other organisms, PCN-1 accumulates in nuclei only during S-phase. By contrast, in the progenitor zone of the germline of C. elegans, PCN-1 accumulated in nuclei during all cell cycle stages. This pattern is similar to accumulation pattern of cyclin E. These observations support the model that mitotic cell cycle regulation in the germline stem and progenitor cells is distinct from somatic cells, as it does not heavily rely on cyclic accumulation of classic cell cycle proteins.

     

Trematodes (Plathelminthes) of <Emphasis Type="Italic">Clarias gariepinus</Emphasis> (Pisces: Clariidae) in Lake Tana,Ethiopia

All of the 166 Clarias gariepinus catfishes in Lake Tana, Ethiopia, were examined for trematode infestation in 2006—2009. Seven trematode species—Eumasenia bangweulensis, Astiotrema reniferum, Orientocreadium batrachoides, Paralecithodendrium chilostomum, Phyllodistomum bavuri, P. tana, and Cladorchiidae gen. sp.—as adult were found. The common catfish parasites were Eumasenia bangweulensis (20% prevalence and 1—62 intensity of invasion), Orientocreadium batrachoides (30% prevalence and 1–31 intensity of invasion), Phyllodistomum bavuri (24.8% prevalence and 1–8 intensity of invasion), Ph. tana (17.6% prevalence and 1–23 intensity of invasion), and Ph. bavuri. Astiotrema reniferum (three specimens were only found) was a rare species; Paralecithodendrium chilostomum was an accidental parasite of catfish. All these trematodes were first recorded in Ethiopia and Eastern Africa.