Aminopeptidase from the skeletal muscle of fresh water fish Tilapia mossambica

An aminopeptidase from the skeletal muscle of fish, Tilapia mossambica, was partially purified to 96-fold using salt precipitation, ion-exchange chromatography and molecular sieve chromatography. The enzyme showed optimum activity between pH 6.5-7.5 at 43 degrees C and Vmax and Km of 14.36 units/mg and 0.059 mM respectively with alanine beta-naphthylamide as the substrate. The aminopeptidase having a molecular weight of 305 kDa was activated by sulphydryl compounds and Co2+ and inhibited by bestatin, puromycin and metal chelators. Inhibition caused by metal chelators could be reversed by the addition of Co2+. Inclusion of L-amino acids, particularly isoleucine and leucine, in the assay medium caused inhibition of the enzyme activity. Substrate specificity together with inhibition and activation pattern indicated that the enzyme is alanine aminopeptidase.     

Rapid and simple identification of human pathogenic heterophyid intestinal fluke metacercariae by PCR-RFLP

Six species of heterophyid intestinal flukes (HIFs) constitute the major endemic zoonotic fish-borne pathogens in Asia: Haplorchis taichui, H. pumilio, H. yokogawai, Procerovum varium, Stellantchasmus falcatus, and Centrocestus formosanus. Several different species of these parasites are often found co-infecting the same second intermediate fish host. Because of their morphological similarities, differentiating between species of HIF metacercariae is difficult, time-consuming, and frequently results in misidentification. In this study, we aimed to develop an efficient and accurate method of identifying metacercariae of these 6 HIFs. Metacercariae were roughly grouped together, based on morphological characteristics seen under a stereomicroscope. Then, PCR-restriction fragment length polymorphism (PCR-RFLP) was used to identify the exact species of each metacercaria, using the 28S ribosomal RNA gene as the genetic marker and MboII as the restriction enzyme. Using a combination of morphological and molecular methods eliminates the need for DNA sequencing and infecting animal subjects to obtain adult worms, increases accuracy, and decreases the need for laborious morphological identification. Because the method is simple, rapid, and relatively cheap compared with PCR-sequencing, it may be an effective tool for epidemiological studies of HIFs in endemic areas.     

Toxicity in Tilapia zilli and Clarias lazera (Pisces) induced by zinc, seasonally

Subadult teleosts, Tilapia zilli and Clarias lazera, were exposed in laboratory bioassays to lethal and sublethal concentrations of zinc, seasonally (at range of temperature between 9.3 +/- 1.5 and 25 +/- 1 degree C). It appears that Tilapia is more susceptible to Zn than Clarias and both species are more resistant to Zn toxicity at lower temperature (during winter). To determine the uptake and tissue distribution of Zn in the two species, gill, liver and muscles were analysed at moderate temperature (during spring). After a 96 hr exposure period, Zn was decreased in the following order: gill greater than liver greater than muscle.     

Prevalence of Haplorchis taichui and Haplorchoides sp. metacercariae in freshwater fish from water reservoirs, Chiang Mai, Thailand

A parasitological investigation on trematode metacercariae was made on 62 freshwater fishes of 13 species in northern Thailand; Cyclocheilichthys apogon, Puntioplites proctozysron, Labiobarbus siamensis, Barbodes gonionotus, Barbodes altus, Henicorhynchus siamensis, Osteochilus hasselti, Notopterus notopterus, Mystacoleucus marginatus, Anabas testudineus, Systomus orphoides, Morulius chrysophykadian, and Hampala macrolepidota. The fish were caught over the summer period (February-May 2007) from 2 Chiang Mai water reservoirs, i.e., the Mae Ngad (UTM 47Q E 503200, 47Q N 2119300) and the Mae Kuang Udomtara (UTM 47Q E 513000, 47Q N 2092600) Reservoirs in Chiang Mai province, Thailand. The prevalence of heterophyid (Haplorchis taichui and Haplorchoides sp.) metacercariae in these fish was 83.9% and 74.2% in the Mae Ngad and Mae Kuang Udomtara Reservoirs, respectively. The highest intensity of heterophyid metacercariae in H. siamensis in the Mae Ngad was 120.4 and that in P. proctozysron in the Mae Kuang Udomtara was 180.0. The fish, A. testudineus, C. apogon, and M. chrysophykadian, were not found to be infected with H. taichui metacercariae. The results show that the freshwater fish in Chiang Mai water reservoirs are heavily infected with H. taichui and Haplorchoides sp. metacercariae.     

Reproductive biology, length-weight relationship and relative condition of pond raised Tilapia zilli (Gervais)

In 'runted' populations of Tilapia zilli positive correlations were found between maturation stages and the following: gonadosomatic index, gonad weight, fish weight and fish length. The minimum size at maturity was 9·0 cm in males and 11·0 cm in females. The mean fecundity in the 'stunted' females was 2359 eggs and it increased with length ( L ) weight (HO and depth ( D ) of the fish. There was, however, no correlation between fecundity and egg size. The results indicated that growth in this 'stunted' T. zilli population was not isometric. The relative condition factor ( Kn ) which approached one indicates good condition.     

Some physiological and biochemical indices of zinc toxicity in two freshwater fishes, Clarias lazera and Tilapia zilli

1. The effects of lethal zinc concentrations on some physiological and biochemical parameters in Clarias lazera and Tilapia zilli were investigated. 2. The analyses of lactate, pyruvate and glycogen in both liver and muscle tissues and the relation among them have been studied in detail. 3. Significant increases were observed in liver and serum proteins, serum alkaline phosphatase (ALP), erythrocyte count (RBCs), haematocrit or packed cell volume (PCV) and haemoglobin (HB) concentrations. 4. Zinc exposure reduced liver and serum acid phosphatase (ACP) as well as liver alkaline phosphatase (ALP).     

Interaction of growth with social behaviour in Tilapia zilli raised in three different temperatures

Three thermal levels were tested on 10-day old T. zilli fry obtained from one spawning to study the effects of temperature on the occurrence of growth depensation in the population reared under controlled environmental conditions. Results showed highest individual growth rate, mortality rates and growth depensation at 30 °C whilst the greatest biomass increase was obtained at an intermediate temperature (27 °C). The enhanced depensation and high mortality rates at the upper limit of the thermal gradient for growth of T. zilli were attributed to an alteration in the behaviour of fish which favoured a few, large, dominant and socially aggressive individuals.     

Studies on the mycotic inhabitants ofCulex pipiens collected from fresh water ponds in Egypt

A total of 20 fungal species belonging to 10 genera were found to be associated with all stages ofCulex pipiens. Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger andPenicillium chrysogenum were the dominant fungi.Beauveria alba andPhoma herbarum. A well known facultative pathogen have been recorded. Most of fungal isolates (63.22%) showed a moderate growth on a synthetic medium containing partially purified chitin. The water extract of bothArtmesia cina andCleome droserifolia showed an inhibitive effect on the protein content and growth of some selected isolates. One ml dose of crude extract ofA. fumigatus killed 90% of the larvae after 192 hr incubation but 36% of the test larvae were killed by the same dose extracted fromP. chrysogenum at the same period of incubation.     

Prevalence of Metagonimus metacercariae in sweetfish, Plecoglossus altivelis, from eastern and southern coastal areas in Korea

The present study was performed to determine the current infecion status of Metagonimus yokogawai metacercariae in sweetfish, Plecoglossus altivelis, collected from several streams in eastern and southern coastal areas of Korea. The sweetfish collected were artificially digested with pepsin-HCl solution and examined under a stereomicroscope in August and September, 2007. Out of 145 sweetfish collected from 10 streams in eastern coasts (Gangwon-do and Gye-ongsangbuk-do), 88 (60.7%) were infected with Metagonimus metacercariae. The average metacercarial density was 61 per infected fish. Among 141 sweetfish collected from 10 streams in southern coasts (Gyeongsangnam-do, Ulsan Metropolitan city, and Jeollanam-do), 140 (99.3%) were infected with Metagonimus metacercariae, and their average density was 949 per infected fish. The present study confirmed that M. yokogawai metacercariae are still prevalent in the sweetfish from several eastern and southern coastal localities. The prevalence and metacercarial density were much higher in the sweetfish from streams of southern coasts than in those of eastern coasts. Therefore, attention should be paid to this small fluke infection, and consumption of raw sweetfish naturally produced in these areas should be prohibited.     

Environmental relationships of aquatic vegetation in the fresh water ecosystem of the Nile Delta,Egypt

In generalized four sectors, 350 stands (water channels) in 50 selected and geo‐referenced sites with eighteen environmental factors were surveyed. The total number of recorded species varied from a sector to another: 21 in the northern, nineteen in the middle, seventeen in the western and sixteen in the eastern. New populations of Cyperus papyrus were explored. Vallisneria spiralis, Elodea canadensis and Najas armata were among seven extinct species that were not recorded few decades ago. The floristic composition alteration may be because of the addition of organic matter of plant and animal origin and the discharge of industrial and sewage effluents. Classification and ordination analyses (DCA) resulted in the segregation of seventeen vegetation groups (communities), three of them were repeatedly recorded; namely Phragmites australis‐Eichhornia crassipes, Phragmites australis‐Myriophyllum spicatum and Potamogeton pectinatus‐Myriophyllum spicatum. Phragmites australis‐Cyperus papyrus group was a new community spreading in the eastern sector of the Delta. Electric conductivity, Fe, Hg and chemical oxygen demand (COD) showed high significant variation (P < 0.001) among the vegetation groups. Other significant variables were Cl, Ca, NO₃, pH and SO₄ (P < 0.047). Redundancy analysis (RDA) was chosen as the appropriate ordination method to perform direct gradient analysis. Trace elements Cu, Fe, Hg and Pb participated in the floristic and chemical composition of each sector.     

Plant remains from Maadi,a predynastic site in lower Egypt

The economy of predynastic Maadi, situated on a Pleistocene terrace, was largely based upon the exploitation of the Nile valley close by. Wheat and barley were the main crop plants. Melon (Cucumis melo) was also grown, but there is no firm evidence of local pulse crop and flax cultivation. The identification of wheat grains posed problems; it is not clear whether in addition to Triticum dicoccum, free-threshing wheat (T. durum/aestivum) is also represented. Both two-rowed barley (Hordeum distichum) and the six-rowed form (H. vulgare) could be demonstrated. The arable weed flora included Lolium (temulentum), Vicia spp., Rumex (dentatus), Phalaris (paradoxa), Lathyrus hirsuta and Medicago (tuberculata). A concentration of Acacia seeds including pod segments points to the use of Acacia pods for tanning. The Nile valley produced most of the timber used by the Maadi inhabitants: Acacia, Tamarix, Salix. Scarce remains of coniferous wood (Cedrus, Juniperus, Pinus) are evidence of foreign trade.     

Prevalence of Toxoplasma gondii antibodies in sera of turkeys, chickens, and ducks from Egypt

Sera from 173 turkeys, 108 chickens, and 48 ducks from Giza, Egypt, were tested for the presence of anti-Toxoplasma gondii antibodies by means of the modified agglutination test using mercaptoethanol and formalin-fixed tachyzoites. The prevalence of anti-T. gondii antibodies (>1:25) among turkeys, chickens, and ducks was 59.5%, 47.2%, and 50%, respectively.     

Surfactant-induced lipid peroxidation in a tropical euryhaline teleost Oreochromis mossambicus (Tilapia) adapted to fresh water

Exposure to anionic (sodium dodecyl sulfate, SDS), cationic (cetyl trimethyl ammonium bromide CTAB) and non ionic (Triton X-100) surfactants at a sub lethal concentration of 1 ppm resulted in severe oxidative stress in the hepatic, renal and cardiac tissues of fresh water adapted Oreochromis mossambicus. Hepatic catalase showed significant increase (P<0.001) in all the surfactant exposed fish, but the renal enzyme was significantly increased only in CTAB dosed fish (P<0.001) and the cardiac enzyme showed significant increase in Triton (P<0.05) and CTAB dosed fish (P<0.001). SOD levels were significantly increased (P<0.001) in hepatic, renal and cardiac tissues of all the surfactant-treated fish. Glutathione reductase also was significantly increased (P<0.001) in the hepatic and renal tissues of surfactant dosed fish except cardiac tissues of CTAB exposed animals. Glutathione levels in the tissues studied were significantly higher in the surfactant treated animals (P<0.001) whereas malondialdehyde levels were significantly elevated only in the hepatic tissues of animals exposed to Triton (P<0.001). The surfactants based on their charge, antioxidant profile and in vivo metabolism may be arranged in the order of decreasing toxicity as CTAB > Triton > SDS. Thus it may be inferred from the present study that the antioxidant defenses and the in vivo metabolism of the surfactants are key factors in deciding the surfactant toxicity.     

Prevalence of Clonorchis sinensis metacercariae in freshwater fish from three latitudinal regions of the Korean Peninsula

A large-scale survey was conducted to investigate the infection status of fresh water fishes with Clonorchis sinensis metacercariae (CsMc) in 3 wide regions, which were tentatively divided by latitudinal levels of the Korean peninsula. A total of 4,071 freshwater fishes were collected from 3 regions, i.e., northern (Gangwon-do: 1,543 fish), middle (Chungcheongbuk-do and Gyeongsangbuk-do: 1,167 fish), and southern areas (Jeollanam-do, Ulsan-si, and Gyeongsangnam-do: 1,361 fish). Each fish was examined by the artificial digestion method from 2003 to 2010. In northern areas, only 11 (0.7%) fish of 2 species, Pungtungia herzi and Squalidus japonicus coreanus from Hantan-gang, Cheolwon-gun, Gangwon-do were infected with av. 2.6 CsMc. In middle areas, 149 (12.8%) fish were infected with av. 164 CsMc. In southern areas, 538 (39.5%) fish were infected with av. 159 CsMc. In the analysis of endemicity in 3 regions with an index fish, P. herzi, 9 (6.2%) of 146 P. herzi from northern areas were infected with av. 2.8 CsMc. In middle areas, 34 (31.8%) of 107 P. herzi were infected with av. 215 CsMc, and in southern areas, 158 (92.9%) of 170 P. herzi were infected with av. 409 CsMc. From these results, it has been confirmed that the infection status of fish with CsMc is obviously different among the 3 latitudinal regions of the Korean peninsula with higher prevalence and burden in southern regions.     

Taxonomy and distribution of fresh water Ostracoda from Socotra Island,Yemen

Eleven species belonging to ten genera of fresh water Ostracoda, have been identified from thirteen sediment samples collected from the bottom of permanent streams running along the N-NE part of Socotra Island. The fauna shows close affinity with the S-E African and S-E Asian assemblages, with interesting findings regarding the Palearctic Limnocythere stationis Vávra, 1891. The taxonomy and geographic distribution of the fauna are here discussed in detail.     

Prevalence,antimicrobial resistance profile,and characterization of multi-drug resistant bacteria from various infected wounds in North Egypt

Multi-drug resistant (MDR) bacteria associated with wounds are extremely escalating. This study aims to survey different wounds in Alexandria hospitals, North Egypt, to explore the prevalence and characteristics of MDR bacteria for future utilization in antibacterial wound dressing designs. Among various bacterial isolates, we determined 22 MDR bacteria could resist different classes of antibiotics. The collected samples exhibited the prevalence of mono-bacterial infections (60%), while 40% included poly-bacterial species due to previous antibiotic administration. Moreover, Gram-negative bacteria showed dominance with a ratio of 63.6%, while Gram-positive bacteria reported 36.4%. Subsequently, the five most virulent bacteria were identified following the molecular approach by 16S rRNA and physiological properties using the VITEK 2 automated system. They were deposited in GenBank as Staphylococcus haemolyticus MST1 ({"type":"entrez-nucleotide","attrs":{"text":"KY550377","term_id":"1304487819","term_text":"KY550377"}}KY550377), Pseudomonas aeruginosa MST2 ({"type":"entrez-nucleotide","attrs":{"text":"KY550378","term_id":"1304487820","term_text":"KY550378"}}KY550378), Klebsiella pneumoniae MST3 ({"type":"entrez-nucleotide","attrs":{"text":"KY550379","term_id":"1304487821","term_text":"KY550379"}}KY550379), Escherichia coli MST4 ({"type":"entrez-nucleotide","attrs":{"text":"KY550380","term_id":"1304487822","term_text":"KY550380"}}KY550380), and Escherichia coli MST5 ({"type":"entrez-nucleotide","attrs":{"text":"KY550381","term_id":"1304487823","term_text":"KY550381"}}KY550381). In terms of isolation source, S. haemolyticus MST1 was isolated from a traumatic wound, while P. aeruginosa MST2 and E. coli MST4 were procured from hernia surgical wounds, and K. pneumoniae MST3 and E. coli MST5 were obtained from diabetic foot ulcers. Antibiotic sensitivity tests exposed that K. pneumoniae MST3, E. coli MST4, and E. coli MST5 are extended-spectrum β-lactamases (ESBLs) bacteria. Moreover, S. haemolyticus MST1 belongs to the methicillin-resistant coagulase-negative staphylococcus (MRCoNS), whereas P. aeruginosa MST2 exhibited resistance to common empirical bactericidal antibiotics. Overall, the study provides new insights into the prevalent MDR bacteria in Egypt for further use as specific models in formulating antibacterial wound dressings.