A natural hybrid of Leuciscus cephalus (L.) and Chalcalburnus chalcoides (Güldenstädt)(Osteichthyes‐Cyprinidae) from Lake Tödürge (Sivas, Turkey)

Hybridization between Leuciscus cephalus and Chalcalburnus chalcoides was identified from biometrical features in 55 fish caught from Lake Tödürge, Sivas, Turkey, between April 1994 and November 1997. The hybrid index V _h for metric and meristic characters was intermediate ( V _h = 45·6) compared with their parents ( L. cephalus V _h = 0 or negative and C. chalcoides V _h ≥ 100). Morphological, metric and meristic features of L. cephalus  ×  C. chalcoides also resembled those of the parents. The majority presented an intermediate position which was best shown by the shape of mouth, caudal fin, gill rakers and pharyngeal teeth, and also by the caudal peduncle depth, head and interorbital width, predorsal and preanal distance, height of anal fin, length of anal base and other characters.     

Occurrence of Streptococcus macedonicus in Italian cheeses

A new approach for the detection and enumeration of Streptococcus macedonicus in cheese was developed. The method which is based on a first screening of cheeses by a PCR assay specific for S. macedonicus followed by plating positive samples on a differential medium (SM medium) was applied to 51 samples derived from PDO and traditional Italian cheeses. Streptococcus macedonicus was found in 16 of the 51 samples examined in the present work. With the exclusion of an Asiago cheese sample in which very high numbers of S. macedonicus (7.13 log CFU g(-1)) were found, the counts of S. macedonicus in SM medium ranged from 2.48 to 4.70 log CFU g(-1). In the same cheeses, total streptococci enumerated onto M17 agar were found at higher concentrations with values up to 7.88 log CFU g(-1). The system developed was particularly useful for the differential count of S. macedonicus in cheese and allowed to evaluate the occurrence of this species within the complex microbial lactic acid bacteria (LAB) population, which is typical of traditional cheeses. Results showed that in the examined cheeses S. macedonicus cannot be considered as a dominant LAB species.     

Hybridization between Alburnus albidus (C.) and Leuciscus cephalus cabeda R. in Italy

Thirty-six specimens of hybrid between the cyprinid species Alburnus albidus and Leuciscus cephalus cabeda were recognized from samples collected from five rivers in southern Italy. In the Alento river hybridization was marked and in a single sample of 66 specimens, 23 were found to be hybrids. The identification of hybrids is easy due to the combination of intermediate characters such as body pigmentation, gill rakers, branched rays of anal and pelvic fins, and some proportional measurements. The growth rate of hybrids is intermediate between the parental forms. Males are more numerous than females.     

Structure and properties of the exopolysaccharide produced by Streptococcus macedonicus Sc136

Streptococcus macedonicus is a Gram positive lactic acid bacterium that is part of the starter flora present in Greek sheep and goat cheeses. The S. macedonicus Sc136 strain produces a high-molecular-mass, highly texturizing exopolysaccharide composed of D-glucose, D-galactose, and N-acetyl-D-glucosamine in the molar ratio of 3:2:1. The structure of the exopolysaccharide produced by S. macedonicus Sc136 was determined by chemical analysis, mass spectrometry, and nuclear magnetic resonance spectroscopy. The repeating unit was shown to be: (see text) The polysaccharide sidechain beta-D-Galf-(1-->6)-beta-D-Glcp-(1-->6)-beta-D-GlcpNAc is a key factor in the highly texturizing properties of the S.macedonicus Sc136 exopolysaccharide. Finally, the trisaccharide sequence beta-D-GlcpNAc-(1-->3)-beta-D-Galp-(1-->4)-beta-D-Glcp corresponds to the internal backbone of the lacto-N-tetraose and lacto-N-neotetraose units, which serve as a structural basis for the large majority of human milk oligosaccharides, an additional property offering an important potential for the development of improved infant nutrition products.     

A new species of Hemibrycon (Characiformes,Characidae, Stevardiinae) from the upper Magdalena River basin in Colombia

Hemibrycon iqueima sp. nov., is described from small streams in the Magdalena drainage at the foothills of the western slope of the Eastern Cordillera of the Colombian Andes, Suarez municipality, Tolima Department, Colombia. The new species is distinguished from its congeners in the Magdalena–Cauca River basin by a combination of characters related to snout–anal‐fin origin length, head length, dorsal–pectoral fin distance, dorsal‐fin–hypural distance, postorbital distance, orbital diameter, snout length, number of total vertebrae, pre‐dorsal scales, scale rows between anal‐fin origin and lateral line, number of branched rays of the anal fin, maxillary teeth number and number and arrangement of hooks on the branched rays of the pectoral and dorsal fins. In addition, the validity of this species is supported by previous molecular analyses that included specimens of the new species that had been erroneously identified. Phylogenetic relationships between the new species and congeners from Pacific coast basins are discussed.     

Atrosalarias hosokawai, a new species of blenny (perciformes: Blenniidae) from the western pacific

A new species of blenny,Atrosalarias hosokawai is described on the basis of 15 specimens from the western Pacific. It is distinguished from the only known congeneric species,A. fuscus (=A. fuscus fuscus+A. fuscus holomelas), by the following: supraorbital cirrus broad and flat (vs. slender and thread-like inA. fuscus); dorsal fin broadly contacting caudal fin (vs. narrow contact); anal fin narrowly contacting caudal fin (vs. usually free or (rarely) very narrow contact); posteriormost dorsal and anal fin rays long (vs. short); first or posteriormost soft dorsal fin ray shortest (vs. posteriormost ray shortest); first soft anal fin ray shortest (vs. posteriormost ray shortest); caudal fin rays branched in specimens over 36.0 mm SL (vs. unbranched); a large dark spot on base of pectoral fin absent (vs. present or absent); a red margin on anterior dorsal fin absent (vs. present). Futhermore,A. hosokawai differs fromA. f. fuscus in having a lower number of dorsal fin spines (ten vs. eleven) and geographical distribution (western Pacific Ocean vs. Indian Ocean and Red Sea). AlthoughA. hosokawai occurs sympatrically withA. f. holomelas, it can be further distinguished from the latter in lacking a large dark spot on base of pectoral fin.     

A new moray eel (Gymnothorax: Muraenidae) from Japan and Hawaii

A new muraenid,Gymnothorax ypsilon, is described from seven specimens from Japan and four from the Hawaiian Islands. It has about 30 narrow dark bars on the body, some of which are Y-shaped on most specimens, a uniformly colored head, an anal fin with a white margin, and 141–153 vertebrae. It differs fromG. pikei, its most similar species, by a white margin of the anal fin.     

Genetic and morphological discrimination of three species of ninespined stickleback Pungitius spp. (Teleostei,Gasterosteidae) in France with the revalidation of Pungitius vulgaris (Mauduyt, 1848)

The taxonomy of French ninespined sticklebacks (Pungitius spp.) has long been controversial. To clarify the taxonomy in this group, we use mitochondrial (COI) and nuclear (RNF213) sequence markers, as well as morphological data. In France, both genetic markers discriminate three evolutionary lineages. Morphological analysis on fresh and type specimens supports the different lineages and the existence of three species in France. Pungitius pungitius, occurring in the North of France and Rhone basin, is characterized by specimens longer than 35 mm SL, by a flat head with a straight or slightly concave snout, typically 9–10 dorsal spines, 10–11 dorsal soft rays, 9–10 anal soft rays, 0–12 scutes on the caudal peduncle with a keel reaching the last anal‐fin ray, longer pelvic fin, post‐dorsal and caudal peduncle lengths, and a slim caudal peduncle (caudal peduncle depth/length 11.8%–21.9%). Pungitius laevis, occurring in France, in the English Channel basins and Loire drainage, differs from the other species by a head rounded with concave snout in specimens longer than 35 mm SL, accentuating the impression of fleshy lips, 0–4 scutes on the caudal peduncle and a higher caudal peduncle depth/length ratio (15.7%–34.5%). Finally, Pungitius vulgaris, endemic to the Vienne River and rivers of south‐western France as far north as the Garonne estuary, is differentiated by a rounded head with a straight or slightly convex snout, the absence of scutes on the caudal peduncle and by having 11 pectoral‐fin rays. Our data confirm the existence of a hybridization zone in the North of France between P. pungitius and P. laevis. As a result, Pungitius lotharingus is invalid, as it was described based on hybrid specimens. A lectotype for P. laevis was designated because the syntypes included hybrids. This revision provides new perspectives for evolutionary biology studies and will have consequences for Pungitius conservation in France.     

Low levels of hybridization between sympatric Arctic char (Salvelinus alpinus) and Dolly Varden char (Salvelinus malma) highlights their genetic distinctiveness and ecological segregation

Understanding the extent of interspecific hybridization and how ecological segregation may influence hybridization requires comprehensively sampling different habitats over a range of life history stages. Arctic char (Salvelinus alpinus) and Dolly Varden (S. malma) are recently diverged salmonid fishes that come into contact in several areas of the North Pacific where they occasionally hybridize. To better quantify the degree of hybridization and ecological segregation between these taxa, we sampled over 700 fish from multiple lake (littoral and profundal) and stream sites in two large, interconnected southwestern Alaskan lakes. Individuals were genotyped at 12 microsatellite markers, and genetic admixture (Q) values generated through Bayesian‐based clustering revealed hybridization levels generally lower than reported in a previous study (<0.6% to 5% of samples classified as late‐generation hybrids). Dolly Varden and Arctic char tended to make different use of stream habitats with the latter apparently abandoning streams for lake habitats after 2–3 years of age. Our results support the distinct biological species status of Dolly Varden and Arctic char and suggest that ecological segregation may be an important factor limiting opportunities for hybridization and/or the ecological performance of hybrid char.     

Microdontochromis rotundiventralis, a new cichlid fish (perciformes: Cichlidae) from Lake Tanganyika

Microdontochromis rotundiventralis, a new species of cichlid fish, is described on the basis of 13 specimens from Nkumbula Island, Lake Tanganyika (Zambia). It is distinct from its only congener,M. tenuidentatus, in having two (rarely one) rows of teeth on both jaws, a rounded distal margin on the pelvic fin, the outermost pelvic fin soft ray length 1.23–1.43 times the innermost ray, a deeper body (depth 26.8–29.1% standard length) and the anal fin with 9 (rarely 8 or 10) soft rays.     

Macedocin,a food-grade lantibiotic produced by Streptococcus macedonicus ACA-DC 198

Streptococcus macedonicus ACA-DC 198, a strain isolated from Greek Kasseri cheese, produces a food-grade lantibiotic named macedocin. Macedocin has a molecular mass of 2,794.76 +/- 0.42 Da, as determined by electrospray mass spectrometry. Partial N-terminal sequence analysis revealed 22 amino acid residues that correspond with the amino acid sequence of the lantibiotics SA-FF22 and SA-M49, both of which were isolated from the pathogen Streptococcus pyogenes. Macedocin inhibits a broad spectrum of lactic acid bacteria, as well as several food spoilage and pathogenic bacteria, including Clostridium tyrobutyricum. It displays a bactericidal effect towards the most sensitive indicator strain, Lactobacillus sakei subsp. sakei LMG 13558(T), while the producer strain itself displays autoinhibition when it is grown under conditions that do not favor bacteriocin production. Macedocin is active at pHs between 4.0 and 9.0, and it retains activity even after incubation for 20 min at 121 degrees C with 1 atm of overpressure. Inhibition of macedocin by proteolytic enzymes is variable.     

Comparative morphology and ecomorphology of the gut in European cyprinids (Telostei)

The patterns of coiling of the gut were compared in 22 species of Eurasian Cyprinidae. In selected species, also the length of gut and mucosal surface structure were compared. Piscivorous ( Aspius aspius ), planktivorous ( Abramis ballerus ) fishes as well as species feeding mainly on plankton and wind-borne' drift'( Alburnus alhurnus, Pelecus cultratus ) have the relatively shortest guts, with only a single loop. The same simple arrangement of a short gut is present in many euryphagous species with more or less carnivorous tendencies ( Abramis sapa, Alburnoides bipunctalus, Abramis brama, Blicca bjoerkna, Chalcalburnus chalcoides memo, Gobio gobio, Leuciscus cephalus, Leuciscus leuciscus, Rutilus rutilus, Scardinius erythrophthalmus. Tinea tinea, Vimba vimba ). Some benthivorous winnowers (oropharyngeal sorters) and species with herbivorous feeding tendencies have relatively long guts showing a more complex pattern of loops and coils ( Barbus barbus, Carassius carassius, Chondrostoma nasus, Ctenopharyngodon idella, Cyprinus carpio ). The goldfish, Carassius auratus , has the most complex coils. Scanning electron microscopy of the mucosal surface revealed five types of folding in the intestinal bulb which were only loosely related to feeding: 1, smooth surface ( Aspius aspius, Leuciscus cephalus, Vimba vimba ); 2, irregularly branching folds ( Alhurnus alburnus, Barbus barbus, Blicca bjoerkna, Chalcalburnus chalcoides memo, Leuciscus leuciscus, Rutilus rutilus, Scardinius erythrophthalmus ); 3, curl-like folds ( Tinea tinea ); 4, net-like folding pattern ( Abramis brama ); 5, honeycomb-like mucosal structure ( Cyprinus carpio ).     

A new sand whiting, Sillago (Sillago) caudicula, from Oman, the Indian Ocean (Perciformes: Sillaginidae)

A new species of sand whiting, Sillago (Sillago) caudicula, is described based on four specimens collected from Oman, the Indian Ocean. It is easily distinguishable from its four known members of the subgenus Sillago by having a smaller head (29.0–30.1% in standard length), 23–24 soft anal fin rays, 35–36 total vertebrae, body depth at the origin of the second dorsal fin slightly deeper than that at the origin of the first dorsal fin, first and second hypurals fused (in adult) or narrowly separated (in young), third and fourth hypurals fused, and 11 dusky midlateral spots on the body.     

Bacteriocin ST91KM, produced by Streptococcus gallolyticus subsp. macedonicus ST91KM, is a narrow-spectrum peptide active against bacteria associated with mastitis in dairy cattle

Streptococcus gallolyticus subsp. macedonicus ST91KM produces a bacteriocin (macedocin ST91KM) active against Streptococcus agalactiae, Streptococcus dysgalactiae subsp. dysgalactiae, Streptococcus uberis, Staphylococcus aureus, and Staphylococcus epidermidis. Macedocin ST91KM is, according to tricine-SDS PAGE, between 2.0 and 2.5 kDa in size. Antimicrobial activity remained unchanged after 2 h of incubation at pH 2.0-10.0 and after 100 min at 100 degrees C. The peptide was inactivated after 20 min at 121 degrees C and when treated with proteolytic enzymes. Treatment with alpha-amylase had no effect on activity, suggesting that the mode of action does not depend on glycosylation. Amplification of the genome of strain ST91KM with primers designed from the macedocin precursor gene (mcdA) produced 2 fragments (approximately 375 and 220 bp) instead of one 150-bp fragment, as recorded for macedocin produced by Streptococcus gallolyticus subsp. macedonicus ACA-DC 198. Strain ACA-DC 198 was not available. However, DNA amplified from strain LMG 18488 (ACA-DC 206), genetically closely related to strain ACA-DC 198, revealed 99% homology to the mcdA of strain ACA-DC 198 (accession No. DQ835394). Macedocin ST91KM may thus be a second putative bacteriocin described for Streptococcus gallolyticus subsp. macedonicus.     

Origin, radiation, dispersion and allopatric hybridization in the chub Leuciscus cephalus

The phylogenetic relationships of 492 chub (Leuciscus cephalus) belonging to 89 populations across the species' range were assessed using 600 base pairs of cytochrome b. Furthermore, nine species belonging to the L. cephalus complex were also analysed (over the whole cytochrome b) in order to test potential allopatric hybridization with L. cephalus sensu stricto (i.e. the chub). Our results show that the chub includes four highly divergent lineages descending from a quick radiation that took place three million years ago. The geographical distribution of these lineages and results of the nested clade analysis indicated that the chub may have originated from Mesopotamia. Chub radiation probably occurred during an important vicariant event such as the isolation of numerous Turkish river systems, a consequence of the uplift of the Anatolian Plateau (formerly covered by a broad inland lake). Dispersion of these lineages arose from the changes in the European hydrographic network and, thus, the chub and endemic species of the L. cephalus complex met by secondary contacts. Our results show several patterns of introgression, from Leuciscus lepidus fully introgressed by chub mitochondrial DNA to Leuciscus borysthenicus where no introgression at all was detected. We assume that these hybridization events might constitute an important evolutionary process for the settlement of the chub in new environments in the Mediterranean area.     

Rhodeus pseudosericeus sp. nov., a new bitterling from South Korea (Cyprinidae, Acheilognathinae)

A new bitterling, Rhodeus pseudosericeus sp. nov., is described on the basis of 31 specimens from five localities included in the Namhan River system, South Korea. The new species is distinguished from other Rhodeus species by the following combination of characters: branched dorsal fin rays 9–10 (mode 9); branched anal fin rays 9–11 (mode 10); longest simple ray of dorsal fin strong and stiff, distally segmented; pelvic fin rays i, 6–7; iris of males blackish; dorsal and anal fins of males grayish in breeding season; karyotype with 2n = 48 (8m + 20sm + 20st). Rhodeus pseudosericeus sp. nov. is similar to Rhodeus sericeus sericeus in the number of pelvic fin and branched dorsal fin rays and the melanophores present on the dorsal fin membrane, but differs from the latter in having a greater body depth, more branched anal fin rays, fewer vertebrae, a lower number of scales in the lateral series, and differing male nuptial coloration. Received: June 30, 2000 / Revised: February 21, 2001 / Accepted: March 6, 2001     

A new anthiine fish (Perciformes: Serranidae),Holanthias kingyo, from the Ryukyu Islands

A new anthiine fish,Holanthias kingyo sp, nov., is described on the basis of two specimens (male and female) from the Ryukyu Is., Japan. The new species is most similar toH. natalensis (Fowler, 1925), known only from South Africa, in having the following characters: dorsal fin soft rays 16 or 17, anal fin soft rays 9, pored lateral line scales 46 or 47, scale rows above lateral line to origin of dorsal fin 9 1/2 or 10 1/2, and gill rakers 10 or 11 +24 or 25=34–36. It differs from the latter in having more scales below the lateral line to the origin of the anal fin (27 1/2 vs. 18–24), a U-shaped caudal fin with paddle-like lobes (vs. deeply forked caudal fin with each lobe ending in a long slender filament), the outer margin of the soft anal fin vertical (vs. gently convex) and brown spots on the body in female (vs. spots absent in females).     

Acid tolerance of Streptococcus macedonicus as assessed by flow cytometry and single-cell sorting

An in situ flow cytometric viability assay employing carboxyfluorescein diacetate and propidium iodide was used to identify Streptococcus macedonicus acid tolerance phenotypes. The logarithmic-phase acid tolerance response (L-ATR) was evident when cells were (i) left to autoacidify unbuffered medium, (ii) transiently exposed to nonlethal acidic pH, or (iii) systematically grown under suboptimal acidic conditions (acid habituation). Stationary-phase ATR was also detected; this phenotype was gradually degenerated while cells resided at this phase. Single-cell analysis of S. macedonicus during induction of L-ATR revealed heterogeneity in both the ability and the rate of tolerance acquisition within clonal populations. L-ATR was found to be partially dependent on de novo protein synthesis and compositional changes of the cell envelope. Interestingly, acid-habituated cells were interlaced in lengthier chains and exhibited an irregular pattern of active peptidoglycan biosynthesis sites when probed with BODIPY FL vancomycin. L-ATR caused cells to retain their membrane potential after lethal challenge, as judged by ratiometric analysis with oxonol [DiBAC(4)(3)]. Furthermore, F-ATPase was important during the induction of L-ATR, but in the case of a fully launched response, inhibition of F-ATPase affected acid resistance only partially. Activities of both F-ATPase and the glucose-specific phosphoenolpyruvate-dependent phosphotransferase system were increased after L-ATR induction, distinguishing S. macedonicus from oral streptococci. Finally, the in situ viability assessment was compared to medium-based recovery after single-cell sorting, revealing that the culturability of subpopulations with identical fluorescence characteristics is dependent on the treatments imposed to the cells prior to acid challenge.