Search results for "NAD"
showing 10 items of 2033 documents
Seasonal Variations in Biochemical Composition of the ClamDosinia corrugatein Relation to the Reproductive Cycle and Environmental Conditions
2016
ABSTRACT Seasonal variations in biochemical composition of the clam Dosinia corrugate were investigated from August 2013 until July 2014 in Zhuanghe Bay in relation to environmental conditions and reproductive cycle. Separate biochemical analyses of the mantle, adductor muscle, foot, and gonad-visceral mass in each sex were undertaken. Spawning took place once a year from July to August and the massive spawning occurred in August with the highest water temperature and chlorophyll a levels. Utilization of glycogen took place during the spawning period, whereas protein was biosynthesized as the mature gametes formed. The glycogen value increased during the resting stage (autumn—winter). The r…
Distribution and seasonal dynamics of Cryptomonads in Sicilian water bodies
2003
Several species with a relevant ecological importance belong to Cryptophyta. Nevertheless, species-level identification from microscopic observations is problematic, lacking recent taxonomic keys. In this study we report our observations on distribution and seasonal dynamics of Cryptomonads in 33 Sicilian water bodies, as well as the main taxonomical problems we encountered. Species of the genera Cryptomonas and Plagioselmis are the most common in the examined water bodies. Their biomass seasonal trends usually show a peak in late winter and early spring. In advanced spring, and also in summer, due to the higher grazing pressure, the Cryptomonads biomass reaches its lowest values. Moreover,…
Pigmentation polymorphism in the invasive amphipod Dikerogammarus villosus : some insights into its maintenance
2004
Dikerogammarus villosus, a freshwater invasive amphipod, exhibits conspicuous pigmentation polymorphism. This polymorphism is documented in two recently colonized areas, the Saand Moselle rivers (north-eastern France), and some of the mechanisms by which pigmentation polymorphism can arise and be maintained are addressed. Body size, reproductive status, fecundity and mate choice are compared among morphs of D. villosus in field samples collected in summer 2001. Body size and female gonad developmental stage were comparable among the different morphs, suggesting that polymorphism is not the result of changes in pigmentation with age or moult- cycle. Fecundity and reproductive status (paired …
Filling gaps: closing the life cycle of the endangered Mediterranean limpet Patella ferruginea Gmelin, 1791 (Gastropoda, Patellidae)
2020
Several reproductive issues and the larval development of the ferruginous limpet, Patella ferruginea Gmelin, 1791, an endangered species endemic from the western Mediterranean Sea, were studied to fill gaps in the knowledge of its life cycle. Average diameter of mature oocytes was 141.83 μm and mean oocyte density in the ovary was 283,800 oocytes/gram. No significant correlations were found between both oocyte diameter or density and female shell length. Female fecundity (number of oocytes per gonad) was significantly correlated with shell length and varied between 189,200 oocytes in a 40.0 mm female and 5,019,200 oocytes in an 86.4 mm female. However, there was considerable variability, in…
No exception to the rule: Candidatus Portiera aleyrodidarum cell wall revisited
2014
International audience; Many insect endosymbionts described so far are gram-negative bacteria. Primary endosymbionts are obligatory bacteria usually harboured by insects inside vacuoles in specialized cells called bacteriocytes. This combination produces a typical three-membrane system with one membrane derived from the insect vacuole and the other two from the bacterial gram-negative cell envelope, composed by the cell wall (the outer membrane plus the periplasmic space) and the plasma membrane (the inner membrane). For the last 21 years, the primary endosymbiont of whiteflies 'Candidatus Portiera aleyrodidarum' was considered an exception to this rule. Previous works stated that only two …
Genome reduction and potential metabolic complementation of the dual endosymbionts in the whitefly Bemisia tabaci
2015
Background The whitefly Bemisia tabaci is an important agricultural pest with global distribution. This phloem-sap feeder harbors a primary symbiont, “Candidatus Portiera aleyrodidarum”, which compensates for the deficient nutritional composition of its food sources, and a variety of secondary symbionts. Interestingly, all of these secondary symbionts are found in co-localization with the primary symbiont within the same bacteriocytes, which should favor the evolution of strong interactions between symbionts. Results In this paper, we analyzed the genome sequences of the primary symbiont Portiera and of the secondary symbiont Hamiltonella in the B. tabaci Mediterranean (MED) species in orde…
Tobacco cells contain a protein, immunologically related to the neutrophil small G protein Rac2 and involved in elicitor-induced oxidative burst.
1997
Abstract Suspension-cultured cells of Nicotiana tabacum generated active oxygen species (AOS) when they were treated with the proteinaceous elicitor, cryptogein. This response was blocked by diphenylene iodonium, an inhibitor of the neutrophil NADPH oxidase. When microsomal extracts of tobacco cells were probed with an antibody directed against the human small G protein Rac2, two immunoreactive proteins were detected at 18.5 and 20.5 kDa. The same experiment performed with cytosolic extracts of tobacco cells led to the observation of a strong immunoreactive protein at 21.5 kDa only in the cryptogein-treated cells. The appearance of this cytosolic protein was related to the production of AOS…
Maternal effects in quail and zebra finches: behavior and hormones.
2013
8 pages; International audience; Maternal effects are influences of parents on offspring phenotype occurring through pathways other than inherited DNA. In birds, two important routes for such transmission are parental behavior and non-DNA egg constituents such as yolk hormones. Offspring traits subject to parental effects include behavior and endocrine function. Research from the Adkins-Regan lab has used three avian species to investigate maternal effects related to hormones and behavior. Experiments with chickens and Japanese quail have shown that maternal sex steroids can influence sex determination to produce biased offspring sex ratios. Because all birds have a ZZ/ZW chromosomal sex de…
Reproductive and bloom patterns of Pelagia noctiluca in the Strait of Messina, Italy
2018
Special issue Vectors of change in the marine environment.-- 11 pages, 7 figures, 1 table, supplementary data https://doi.org/10.1016/j.ecss.2016.01.002
Evidence for ontogenetically and morphologically distinct alternative reproductive tactics in the invasive Round Goby Neogobius melanostomus.
2017
Alternative reproductive tactics are characterized by the occurrence of discrete alternative morphs that differ in behavioural, morphological and physiological traits within the same sex. Although much effort has been made to describe the behaviour, morphology and physiology of such alternative morphs, less effort has been invested investigating how much overlap there is in the characteristics of such morphs in natural populations. We studied random population samples of the invasive Round Goby Neogobius melanostomus from five different localities in the river Rhine system in the Netherlands. We found two morphologically and physiologically distinct male morphs which likely represent altern…