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Sphyrion lumpi is a sexually dimorphic, parasitic copepod which causes significant losses in fisheries in the North Atlantic. Studies involving both light and scanning electron microscopy revealed important details of the external morphology of both sexes that are discussed in relation to other members of the family Sphyriidae. Conclusions are drawn regarding the life cycle of S. lumpi. The present finding of this parasite on Urophycis tenuis constitutes a new host record. 相似文献
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Debraj Kole Subinoy Mondal Apurba Ratan Ghosh 《Proceedings of the Zoological Society》2018,71(2):178-185
Effects of two different concentrations of arsenic (8.88 mg/l and 17.76 mg/l i.e., 25 and 50% of LC50 value) respectively and chromium (15.45 mg/l and 30.90 mg/l i.e., 25 and 50% of LC50 value respectively) were evaluated on digestive enzymes of Anabas testudineus for a period of 30 days under laboratory condition. Here As1 and As2, and Cr1 and Cr2 were referred to indicate the 25 and 50% of LC50 value of arsenic and chromium respectively. The result of different enzymes in different tissues was as follows: amylase and lipase activities showed highest in stomach, i.e., 466.81 and 283.33% respectively at 50% concentration of chromium; but moderate (272.78% at 25% of Cr and 264.65% at 50% of As) followed by lowest 219.07% at 25% As concentration. Protease activity at different concentrations of metals was in the order of As2 > As1 > Cr2 > Cr1. Protease activity showed highest in As2 or 50% concentration of As (397.92%) and lowest in 25% of Cr (316.39%). Lipase activity showed highest increment in intestine under As2 (409.23%) and lowest activity in Cr1 (137.84%). In intestine, the protease activity increased at As1 (288.99%) and the highest at As2 i.e., 367.39% compared to other concentrations. The significant changes (p > 0.05) in the enzyme activities in the different tissues like stomach and intestine in regard to different doses were investigated along with regression lines. So, it can be inferred that digestive enzyme activities of A. testudineus may be considered as the potential biomarkers for arsenic and chromium contamination in aquatic systems. 相似文献
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《Journal of Genetic Engineering and Biotechnology》2014,12(2):103-110
In the present investigation were evaluated the antifungal and antibacterial activities of Nano-silver (NS). Two separate experiments were done to evaluate the potential of silver nanoparticles in controlling the contamination of G × N15 micro-propagation. In the first experiment, a factorial experiment based on a completely randomized design with 15 treatments including five different NS concentrations (0, 50, 100, 150 and 200 ppm) and three soaking time of explants (3, 5 and 7 min) with five replications was conducted. In the other experiment, NS was added to Murashige and Skoog (MS) medium with concentrations of 0, 50, 100, 150 and 200 ppm in a completely randomized design. Results showed that the application of 100 and 150 ppm NS both as an immersion and as added directly to the culture medium significantly reduces internal and external contaminations compared with the control group. Using NS in culture medium was more efficient to reduce fungal and bacterial contamination than immersion. High concentrations of NS had an adverse effect on the viability of G × N15 single nodes and this effect was more serious in immersed explants in NS than directly added NS ones regarding the viability of buds and plantlet regeneration. In conclusion, due to high contamination of woody plants especially fruit trees and also adverse environmental effects of mercury chloride, the NS solution can be used as a low risk bactericide in micro-propagation of G × N15 and can be an appropriate alternative to mercury chloride in the future. 相似文献
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Yu Wang Douglas C. Goodwin 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(1):362-371
Catalase–peroxidases (KatGs) have two peroxidase-like domains. The N-terminal domain contains the heme-dependent, bifunctional active site. Though the C-terminal domain lacks the ability to bind heme or directly catalyze any reaction, it has been proposed to serve as a platform to direct the folding of the N-terminal domain. Toward such a purpose, its I′-helix is highly conserved and appears at the interface between the two domains. Single and multiple substitution variants targeting highly conserved residues of the I′-helix were generated for intact KatG as well as the stand-alone C-terminal domain (KatGC). Single variants of intact KatG produced only subtle variations in spectroscopic and catalytic properties of the enzyme. However, the double and quadruple variants showed substantial increases in hexa-coordinate low-spin heme and diminished enzyme activity, similar to that observed for the N-terminal domain on its own (KatGN). The analogous variants of KatGC showed a much more profound loss of function as evaluated by their ability to return KatGN to its active conformation. All of the single variants showed a substantial decrease in the rate and extent of KatGN reactivation, but with two substitutions, KatGC completely lost its capacity for the reactivation of KatGN. These results suggest that the I′-helix is central to direct structural adjustments in the adjacent N-terminal domain and supports the hypothesis that the C-terminal domain serves as a platform to direct N-terminal domain conformation and bifunctionality. 相似文献
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The lesser mealworm, Alphitobius diaperinus (Panzer), is the main insect pest in the poultry industry, thus causing serious damage to production. In this work, the properties of midgut α-amylase from larvae of A. diaperinus were characterized, and its in vitro activity to proteinaceous preparations from different cultivars of common bean (Phaseolus vulgaris) was determined, as well as the amylolitic activity of insects reared on different types of poultry diet. In order to establish some assay conditions, time course and enzyme concentration upon the reaction rate were determined. Product proceeded linearly with time, and the activity was directly proportional to the enzyme concentration. Banding patterns in mildly denaturing electrophoresis showed a single band with apparent molecular weight of 42 kDa. α-Amylase reached optimal temperature at 45°C and pH 5.0 as the optimal one. It maintained 34.6% of the activity after being kept at 60°C for 5 min, and 23%, after 60 min. However, at 80°C, only 14 and 6% remained after 5 and 60 min, respectively. The presence of Ca2+ and Na+ ions decreased the enzyme activity at concentrations higher than 2 and 100 mM, respectively. The activity was significantly inhibited by some proteinaceous extracts from common bean cultivars, and it declined with increasing proteinaceous concentration. No significant difference was observed when the amylolytic activity was determined in A. diaperinus reared on different poultry diets, offered to broilers in the starter, grower, finisher, and layer phases. 相似文献
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Photosynthesis Research - Jacques Breton spent his 39 years of professional life at Saclay, a center of the French Atomic Energy Commission. He studied photosynthesis with various advanced... 相似文献
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The structure transition of λ-DNA induced by cationic surfactant cellar media was investigated by using CD, SEM and AFM. The
experimental data of CD revealed that λ-DNA can be induced from B-form to a collapsed structure with the addition of the cationic
surfactant CTAB to the system. The condensed process of λ-DNA from coil state to small globular state (diameter about 1.25
μm) and finally big globular state (diameter about 5.4 μm) was observed by using SEM and AFM.
Project supported by the Ninth Five-Year Great and Important Project of the Chinese Academy of Sciences and National Postdoctoral
Science Foundation of China. 相似文献
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New and known homo- and heterodinuclear RuII and OsII complexes with 4,4-bipyridine (4,4-bpy), pyrazine, and 4-pyCH=CHpy-4 as bridging ligands (LL) of the type [Cl(bpy)2M(LL)MCl(bpy)2]X2 (bpy=2,2-bipyridine; X=PF6 or BF4) have been studied in their capacity to exchange electrons with a reduced active site of glucose oxidase (GO) from Aspergillus niger. Cyclic voltammograms (CVs) of the dimers in the aqueous buffered solution, when compared with CVs of the parent monomeric species [MCl(LL)(bpy)2]BF4 and [MCl2(bpy)2] which could be generated at pH7, if the dimers undergo monomerization, indicate that the dimers are the dominating species under such conditions. All electrochemically oxidized dinuclear complexes studied show high rates of oxidation of GO reduced by d-glucose and the corresponding observed second-order rate constants are in the range (5–64)×105 M–1 s–1 at 25 °C. However, these values are lower than that for the mononuclear complex [OsCl(4,4-bpy)(bpy)2]BF4 (1.1×107 M–1 s–1), suggesting that potentially two-electron dimeric mediators have no advantage compared with corresponding monomeric complexes of RuII and OsII. The structure of [OsCl(4,4-bpy)(bpy)2]BF4 was confirmed by X-ray crystallography. The monodentate 4,4-bpy ligand is coordinated cis to the chloride. Its higher reactivity toward reduced GO is accounted for in terms of the antenna effect of the monodentate 4,4-bpy ligand. The antenna length equals 9.2 Å and matches the depth of the enzyme active site pocket of ca. 10 Å. The mechanism of the antenna effect is discussed 相似文献
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The conformation of Arginine E7 in the mutant Deoxyhaemoglobin Zürich differs from that found in the carbonmonoxy form. Comparison with the structure of normal haemoglobin-A allows the changes in oxygen affinity and binding kinetics to be rationalized. 相似文献
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P. A. Saveliev S. F. Solomatov O. I. Pushchina A. A. Balanov 《Journal of Ichthyology》2011,51(9):745-757
With consideration of investigations made in 2004–2010, the spatial distribution of Lycodes tanakae, as well as some traits of its biology in Primor’e waters, is described. This species occurs all over the investigated region—from
42° to 49°N as explained by hydrological properties of bottom waters and by the bottom relief of this water area. In Promor’e
waters, Lycodes tanakae occurs at depths of 87–1034 m. However, the majority of specimens (90%) prefers depths of 200–700 m. Thus, it can be attributed
to the mesobathial ecological fish group. In spring and summer, juveniles of L. tanakae live at similar depths (200–350 m) where this species seems to spawn. In catches, L. tanakae is represented by specimens 11–90 cm in length, 0.1–4.9 kg in weight, and age from 1 to 10 years. The bulk of catches consists
of specimens 40–70 cm long (62%), up to 2.2 kg in weight (90%), and of the age 4–7 years (72%). Sexual dimorphism in linear
dimensions is not determined in L. tanakae. In summer, the ration of L. tanakae in Primor’e waters consists predominantly of cephalopods (on average, 59.4% of food weight). A noticeable part belongs to
decapods (19.8%) and fish juveniles (16.6%). The smallest analyzed specimens consume small decapods and polychaetes. At the
body length over 40 cm, L. tanakae pass over to predation. The value of the daily ration of Lycodes tanakae is, on average, 1.5% of the body weight. 相似文献
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《Comptes Rendus Palevol》2014,13(2):65-71
A new genus and species, Cryptohelops menaticus gen. et sp. n., are described from the Palaeocene of Menat (France). The new genus belongs to the subtribe Helopina of the tribe Helopini (subfamily Tenebrioninae of Tenebrionidae) based on the coarse and dense punctation of the hypomera, shape of the prosternum and metepisterna, a similar appearance to the native genera Helops and Stenohelops and the structure of the epipleura. The new genus also resembles Raiboscelis and Entomogonus by having the protibiae excised along the base of the inner side. The new genus is the oldest representative of the tribe Helopini. Four species of Helops sensu lato previously described from the Oligocene (H. wetteravicus K. Heyden et L. Heyden, 1865) and Miocene (H. atticus Redtenbacher in Ungern, 1867; H. meissneri Heer, 1847 and H. molassicus Heer, 1883) lack important diagnostic characters and should be regarded as members of the tribe Helopini with uncertain generic attribution. 相似文献
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Sorghum (Sorghum bicolor L. Moench) has two isozymes of the cyanogenic β-glucosidase dhurrinase: dhurrinase-1 (Dhr1) and dhurrinase-2 (Dhr2). A nearly full-length cDNA encoding dhurrinase was isolated from 4-d-old etiolated seedlings and sequenced. The cDNA has a 1695-nucleotide-long open reading frame, which codes for a 565-amino acid-long precursor and a 514-amino acid-long mature protein, respectively. Deduced amino acid sequence of the sorghum Dhr showed 70% identity with two maize (Zea mays) β-glucosidase isozymes. Southern-blot data suggested that β-glu-cosidase is encoded by a small multigene family in sorghum. Northern-blot data indicated that the mRNA corresponding to the cloned Dhr cDNA is present at high levels in the node and upper half of the mesocotyl in etiolated seedlings but at low levels in the root—only in the zone of elongation and the tip region. Light-grown seedling parts had lower levels of Dhr mRNA than those of etiolated seedlings. Immunoblot analysis performed using maize-anti-β-glucosidase sera detected two distinct dhurrinases (57 and 62 kD) in sorghum. The distribution of Dhr activity in different plant parts supports the mRNA and immunoreactive protein data, suggesting that the cloned cDNA corresponds to the Dhr1 (57 kD) isozyme and that the dhr1 gene shows organ-specific expression. 相似文献
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The genus Planinasus Cresson is revised and includes 18 extant and one fossil species. We clarify the status of the three previously described species and describe 15 new species as follows (type locality in parenthesis): Planinasus aenigmaticus (Colombia. Bogota: Bogota (04°35.8''N, 74°08.8''W)), Planinasus neotropicus (Panama. Canal Zone: Barro Colorado Island (09°09.1''N, 79°50.8''W)), Planinasus kotrbae (Ecuador. Orellana: Rio Tiputini Biodiversity Station (0°38.2''S, 76°08.9''W)), Planinasus miradorus (Brazil. Maranhão: Parque Estadual Mirador, Base da Geraldina (06°22.2''S, 44°21.8''W)), Planinasus tobagoensis (Trinidad and Tobago. Tobago. St. John: Parlatuvier (11°17.9''N, 60°39''W)), Planinasus xanthops (Ecuador. Orellana: Rio Tiputini Biodiversity Station (0°38.2''S, 76°8.9''W)), Planinasus argentifacies (Peru. Madre de Dios: Río Manu, Pakitza (11°56.6''S, 71°16.9''W; 250 m)), Planinasus insulanus (Dominican Republic. La Vega: near Jarabacoa, Salto Guasara (19°04.4''N, 70°42.1''W, 680 m)), Planinasus nigritarsus (Guyana. Conservation of Ecological Interactions and Biotic Associations (CEIBA; ca. 40 km S Georgetown; 06°29.9''N, 58°13.1''W)), Planinasus atriclypeus (Brazil. Rio de Janeiro: Rio de Janeiro, Floresta da Tijuca (22°57.6''S, 43°16.4''W)), Planinasus atrifrons (Bolivia. Santa Cruz: Ichilo, Buena Vista (4-6 km SSE; Hotel Flora y Fauna; 17°29.95''S, 63°33.15''W; 4-500 m)), P. flavicoxalis (West Indies. Dominica. St. David: 1.6 km N of junction of roads to Rosalie and Castle Bruce (15°23.8''N, 61°18.6''W)), Planinasus mcalpineorum (Mexico. Chiapas: Cacahoatan (7 km N; 15°04.1''N, 92°07.4''W)), Planinasus nigrifacies (Brazil. São Paulo: Mogi das Cruzes, Serra do Itapeti (23°31.5''S, 46°11.2''W)), Planinasus obscuripennis (Peru. Madre de Dios: Río Manu, Erika (near Salvación; 12°50.7''S, 71°23.3''W; 550 m)). In addition to external characters, we also describe and illustrate structures of the male terminalia and for Planinasus kotrbae
sp. n., the internal female reproductive organs. Detailed locality data and distribution maps for all species are provided. For perspective and to facilitate genus-group and species-group recognition, the family Periscelididae and subfamily Stenomicrinae are diagnosed and for the latter, a key to included genera is provided. 相似文献
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Aminophosphine oxides and aminophosphonates are, in general, very stable compounds. However, following phosphorus–carbon bond
cleavage in aqueous acidic media these compounds sometimes decompose to phosphonic acids derivatives (PIII). Despite some controversy in the literature, careful analysis supported by theoretical studies leads to the conclusion that
decomposition to PIII derivatives proceeds via an elimination reaction.
Figure The decomposition of α-aminophosphine oxides to phosphonic acid derivatives (PIII) 相似文献
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