Changes In Biochemical Composition Research Articles

Alterations in erythrocyte membrane fluidity and Na+/K+-ATPase activity in chronic alcoholics

Ethanol disorders biological membranes causing perturbations in the bilayer and also by altering the physicochemical properties of membrane lipids. But, chronic alcohol consumption also increases nitric oxide (NO) production. There was no systemic study was done related to alcohol-induced production of NO and consequent formation of peroxynitrite mediated changes in biophysical and biochemical properties, structure, composition, integrity and function of erythrocyte membranes in chronic alcoholics. Hence, keeping all these conditions in mind the present study was undertaken to investigate the role of over produced nitric oxide on red cell membrane physicochemical properties in chronic alcoholics. Human male volunteers aged 44 +/- 6 years with similar dietary habits were divided into two groups, namely nonalcoholic controls and chronic alcoholics (~125 g of alcohol at least five times per week for the past 10-12 years). Elevated nitrite and nitrate levels in plasma and lysate, changes in erythrocyte membrane individual phospholipid composition, increased lipid peroxidation, protein carbonyls, cholesterol and phospholipids ratio (C/P ratio) and anisotropic value (gamma) with decreased sulfhydryl groups and Na(+)/K(+)-ATPase activity in alcoholics was evident from this study. RBC lysate NO was positively correlated with C/P ratio (r = 0.547) and anisotropic (gamma) value (r = 0.428), Na(+)/K(+)-ATPase activity was negatively correlated with RBC lysate NO (r = -0.372) and anisotropic (gamma) value (r = -0.624) in alcoholics. Alcohol-induced overproduction of nitric oxide reacts with superoxide radicals to produce peroxynitrite, which appears to be responsible for changes in erythrocyte membrane lipids and the activity of Na(+)/K(+)-ATPase.

Seasonal changes in reproductive activity and biochemical composition of the razor clam Sinonovacula constricta (Lamarck 1818)

The reproductive cycle and seasonal variations in biochemical composition of the razor clam Sinonovacula constricta (Lamarck) from the Yellow River delta in China were investigated from April 2007 to March 2008 in relation to environmental factors. Histological analysis indicated that the gametogenesis of the S. constricta comprised two phases: a resting phase (February–May) and gametogenesis, including ripeness and spawning, during the rest of the year. Gametogenesis of S. constricta began in June–July and was completed during September–October when food was abundant. A significant decrease in the glycogen content of all tissues both in the female and male during sexual maturation suggests that carbohydrates play the most important role in reproduction of this species. The protein and lipid content increased in association with the gametogenesis in the female gonads, indicating that they are the major organic component of oocytes. Conversely, the protein and lipid decreased in the male gonads and other tissues, demonstrating that they also support reproduction after the glycogen is depleted. The RNA/DNA ratio is a valuable indicator of maturation both in the female and male. The results obtained in this study provide useful information for developing management strategies of S. constricta populations in this area, and for optimizing the hatchery-based seed production.

Selection for fitness at the individual or population levels: Modelling effects of genetic modifications in microalgae on productivity and environmental safety

A mechanistic model of microalgae is used to explore the implications of modifying microalgal chlorophyll content and photosynthetic efficiency with an aim to optimising commercial biomass production. The models show the potential for a 10 fold increase in microalgae productivity in genetically modified versus unmodified configurations, while also enabling the use of bioreactors of greater optical depth operating at lower dilution rates. Analysis suggests that natural selection of a trait benefiting the individual (high Chl:C max, i.e., high antennae size) conflicts with artificial selection of a trait (low Chl:C max) of most benefit to production at the population level. The implication is that GM strains rather than strains selected from nature will be most beneficial for commercial algal biofuels production. Further, escaped GM algae populations may, depending on the specific nature of the modification, be quickly out-competed by the natural forms because individually a high Chl:C is beneficial in low light environments. However, it remains possible that changes in biochemical composition associated with genetic modification of photosystem competence, or with other selection processes to enhance commercial gain, may adversely affect the value of such organisms as prey for zooplankton, leading to the unwanted generation of future harmful algae.

Structural and proteomic analyses reveal regional brain differences during honeybee aging

Among insects, learning is particularly well studied in the fruit fly Drosophila melanogaster and the honeybee Apis mellifera. A senescence-dependent decline in classic pavlovian conditioning is demonstrated for both species. To understand how aging affects learning, genetic approaches used with Drosophila can benefit from complementary studies in Apis. Specifically, honeybees have a larger brain size allowing for compartment-specific approaches, and a unique life-history plasticity. They usually perform within-nest tasks early in life (nest bees) and later they collect food (foragers). Senescence of learning performance is a function of the bees' foraging duration but underlying causes are poorly understood. As cognitive aging is commonly associated with structural and biochemical changes in the brain, we hypothesized that brain areas implicated in learning change in synaptic and biochemical composition with increased foraging duration. First, we used synapse-specific immunohistochemistry and proteomics to screen for alterations in the calyx region of the mushroom body, a key structure for memory formation. Using proteomics, we next profiled the central brain, which comprises all higher-order integration centers. We show that, with increased foraging duration, levels of kinases, synaptic- and neuronal growth-related proteins decline in the central brain while the calyx region remains intact both in structure and biochemistry. We suggest that proteome-level changes within major anatomical sites of memory formation other than the calyx region could be central to learning dysfunction. These include large compartments of the central brain, such as the mushroom body's output regions and the antennal lobes. Our data provide novel information toward heterogeneity in the aging insect brain, and demonstrate advantages of the honeybee for invertebrate neurogerontological research.

Seasonal changes in biochemical composition of the mangrove oyster, <i>Crossostrea Tulipa</i>(Lamarck) occurring in two coastal water bodies in Ghana

Seasonal changes in biochemical composition of the mangrove oyster, <i>Crossostrea Tulipa</i>(Lamarck) occurring in two coastal water bodies in Ghana

Degradation of sea urchin feces in a rocky subtidal ecosystem: implications for nutrient cycling and energy flow

During destructive grazing events in the Northwest Atlantic, sea urchins Strongylocen- trotus droebachiensis consume large amounts of kelp biomass, transforming this material into feces. To determine the role of urchin fecal material in nutrient cycling and energy flow in the shallow rocky subtidal zone, we monitored the physical, chemical, and microbial degradation of urchin feces at 6, 9, 12, and 16 m depth over 19 d at a wave-exposed site on the Atlantic coast of Nova Scotia by quan- tifying changes in fecal biochemical composition, pellet size, and settling velocity. We observed an exponential loss of fecal material and rapid degradation of total and labile organic matter fractions; this suggests that urchin fecal production plays an important role in local nutrient cycling and energy flow via the microbial food web. As the feces were further degraded there was a relative increase in organic carbon, nitrogen, lipid, and available energy content, and a decrease in the C:N ratio, sug- gesting that degraded urchin feces are an important food source for suspension- and deposit-feeding invertebrates. The settling velocity of the feces also decreased over time, likely due to a decrease in fecal pellet density. Older, less dense feces with a relatively high energy content are more likely to be suspended and transported horizontally, providing a mechanism for the export of kelp primary pro- duction to deeper, less productive waters.

Cultures of microorganisms: An example of informational interaction

To changing environmental conditions, a living organism responds by a certain reaction which is a measure of the openness of the system. Changes in biochemical composition and spatial orientation of major biopolymers of cells and culture liquid of unicellular green algae are shown by a noninvasive analysis.

Physiological changes in relation to growth and ripening of khirni [Manilkara hexandra(Roxb.) Dubard] fruit

Introduction. Fruit ripening is the process resulting in changes in color, taste and texture, which make the fruit acceptable for consumption. Since a wide spectrum of physiological, biochemical and organoleptic changes are involved in the development of a soft, edible, ripe fruit, we studied theses changes in an underutilized fruit, khirni [Manilkara hexandra (Roxb.) Dubard]. Materials and methods. The changes in biochemical composition, which includes chlorophylls, carotenoids, anthocyanins, sugars, starch, free amino acids, phenols and proteins, and the specific activity of enzymes such as amylase, invertase, catalase, peroxidase, pectinmethylesterase, polygalacturanase and cellulase were analyzed in the fruit of Manilkara hexandra at five sequential developmental stages (young, premature, mature, preripened and ripened fruit stages). Results and discussion. The pulp of khirni fruit tastes sour during its growth period, but turns sweet when it ripens. A decreasing trend in chlorophylls occurs simultaneously with an increase in the quantity of total carotenoids and anthocyanins. Further, an increase in the quantity of sugars, proteins and phenols occurs towards the ripened stage, but starch and total free amino acids show a decrease in their quantities. Also, khirni fruit exhibits climacteric behavior with its increased rate of respiration and ethylene production. The moderate to significant changes in the activity of enzymes such as amylase, invertase, catalase and peroxidase involved in a number of catabolic and anabolic reactions indicate that these enzymes also have an active role in the process of khirni fruit growth and ripening.

Biochemical composition and somatic growth of pelagic larvae of three fish species from the Bay of Biscay

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 382:173-183 (2009) - DOI: https://doi.org/10.3354/meps07941 Biochemical composition and somatic growth of pelagic larvae of three fish species from the Bay of Biscay E. Díaz1,* J. M. Txurruka2, F. Villate3 1AZTI Arrantza Baliabideen Saila, Txatxarramendi ugartea, z/g. 48395 Sukarrieta, Bizkaia, Spain 2University of the Basque Country, Department of Genetics, Physical Anthropology and Animal Physiology, 48080 Bilbao, Spain 3University of the Basque Country, Department of Plant Biology and Ecology, 48080 Bilbao, Spain *Email: ediaz@suk.azti.es ABSTRACT: The growth strategies of pelagic larvae of 3 fish species from the Bay of Biscay belonging to 2 different shape groups, the eel-like anchovy Engraulis encrasicolus and sardine Sardina pilchardus, and the tadpole-like horse mackerel Trachurus trachurus, are compared in terms of changes in their biochemical composition and energy allocation. In anchovy and sardine, the relative amount of protein increased and relative amounts of carbohydrates and lipids decreased throughout their growth. The biochemical composition in horse mackerel did not change significantly during growth. Differences between the 2 shape groups could be associated with the various energy allocation patterns related to dissimilar growth strategies. Although the patterns of change in biochemical composition during growth are different in the 2 shape groups, they show a very similar biochemical composition at the notochord flexion stage, indicating convergences in life-history patterns of the different species. KEY WORDS: Anchovy · Sardine · Horse mackerel · Fish larvae · Biochemical composition · RNA/DNA · Growth strategy Full text in pdf format PreviousNextCite this article as: Díaz E, Txurruka JM, Villate F (2009) Biochemical composition and somatic growth of pelagic larvae of three fish species from the Bay of Biscay. Mar Ecol Prog Ser 382:173-183. https://doi.org/10.3354/meps07941 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 382. Online publication date: April 30, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

Leaf and twig 13C during growth in relation to biochemical composition and respired CO2

In deciduous trees, the delta(13)C values of leaves are known to diverge during growth from those of woody organs. The main purpose of this study is to determine whether the divergence in delta(13)C between leaves and current-year twigs of Fagus sylvatica (L.) is influenced by changes (i) in the relative contents of organic matter fractions and (ii) in the delta(13)C of respired CO(2). The delta(13)C values of bulk matter, extractive-free matter, lignin, holocellulose, starch, soluble sugars, water-soluble fraction and respired CO(2), as well as their relative contents in bulk matter were determined. The delta(13)C values of biochemical fractions and respired CO(2) showed very similar temporal variations for both leaves and twigs. Variations in bulk matter delta(13)C during growth were, therefore, poorly explained by changes in biochemical composition or in respiratory fractionation and were attributed to the transition from (13)C-enriched reserves (mainly starch) to (13)C-depleted new photoassimilates. The divergence between leaves and twigs was related to higher values of soluble sugar delta(13)C in twigs. However, the difference between lignin and holocellulose delta(13)C varied during growth. This phenomenon was attributed to the delay between holocellulose and lignin deposition. These results may have implications for analysis of organic matter delta(13)C in trees and forest ecosystems.

Photonic and Magnetic Force Micro-piston: An integrated force/microfluidic device for investigating expansion and compression stress in chromatin/chromosomes and their roles in chromosome function.

Dynamic changes in the state of chromosomes (changes in the level of chromatin compaction) take place in the confined environment of the nucleus throughout the cell cycle. These changes have been hypothesized to determine both the mechanical properties and, as a direct consequence of such effects, the function of chromosomes (Kleckner et al., 2004). To test this hypothesis, we have developed devices that can use either photon pressure or magnetic force to push beads in microfluidic channels, creating compression chambers in which the response of a confined biological specimen can be investigated as a function of force as well as changes in buffer, extract or biochemical composition. Photon pressure is generated by a weakly focused laser beam emanating from a fiber optic mounted directly on to our microfluidic chip, thus eliminating the need for the fixed optics associated with typical laser trapping systems. As a result, heating and the associated risk to a biological specimen is greatly reduced. Magnetic force is generated by a thin foil electromagnet system capable of producing high field and field gradients that, when used in conjuction with a 4.5 micron magnetic bead, can produce hundreds of picoNewtons of compression force on a biological specimen. These devices will be used to address three immediate questions of interest: (i) What is the magnitude of the force generated by chromatin expansion? (ii) When two chromatin masses are present, to what extent do they intermingle? and (iii) When expansion is constrained by confinement, does the resulting compression stress alter the structure and/or properties of chromatin?

Flocs surface functionality assessment of sonicated activated sludge in relation with physico-chemical properties

Flocs surface functional groups evolutions due to an ultrasonic treatment were investigated in respect with the mechanisms involved during sonication. Activated sludge surface functional groups changes were studied after treatment of a sample at different ultrasonic specific energies. Sludge functionality was qualitatively assessed by recording the infrared (FT-IR) spectra of centrifugation pellets. Potentiometric titration coupled with proton surface complexation modeling was used to assess the nature and quantity of ionizable functional groups present at the floc surface and in the aqueous phase. These evolutions were linked to changes of both mixed liquor biochemical composition (TSS, VSS, COD, proteins, humic like substances, polysaccharides) and physical properties (floc size and settleability). Observations carried out showed that activated sludge flocs were essentially mechanically disintegrated by ultrasonic waves: the nature of chemical bonds observed by FT-IR did not shift after ultrasonic treatment. Moreover, the total number of ionizable functional groups measured by potentiometric titrations remained constant during sonication. However, due to the solubilization of organic components induced by cavitation process, the corresponding ionizable functional groups (carboxyl, hydroxyl, amine) were transferred from particulate to soluble fraction. Moreover, due to the variable amount of proteins, humic like substances and polysaccharides solubilised, the relative contributions of carboxyl, hydroxyl and amine groups varied at floc surface.

Change in Biochemical Composition in the Ovary of Snow Crab, Chionoecetes Opilio, During Seasonal Development

Abstract Snow crabs, Chionoecetes opilio, were obtained approximately bimonthly from the eastern Bering Sea and sampled for biometric information and biochemical analysis of ovaries, which included determination of moisture, ash, total lipid, protein content, fatty acid and lipid profiles. Development of the ovary during the reproductive cycle largely followed the pattern seen in other crustaceans, namely an increase in size and lipid content. However, the increase in lipid content occurred early in the development cycle and was stable thereafter. Both the lipid and fatty acid profiles were relatively stable throughout development. The fatty acid profile of the ovary of C. opilio differs from other crustaceans by having relatively high percentages of eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), and low percentage of arachidonic acid (ARA). Forward stepwise general discriminant analysis of fatty acid profile indicated that it can be used to classify the development of ovaries at least during the ...

Detection of drug-induced cellular changes using confocal Raman spectroscopy on patterned single-cell biosensors

We report on a cell-based biosensor application that utilizes patterned single-cell arrays combined with confocal Raman spectroscopy to observe the time-dependent drug response of individual cells in real time. The patterned single-cell platform enables individual cells to be easily located and continuously addressable for Raman spectroscopy characterization of biochemical compositional changes in a non-destructive, quantitative manner so that discrete cellular behavior and cell-to-cell variations are preserved. In this study, human medulloblastoma (DAOY) cells were exposed to the common chemotherapeutic agent etoposide, and Raman spectra from patterned cells were recorded over 48 hours. It was found that 87.5% of the cells monitored exhibited a sharp decrease in DNA and protein associated peaks 48 hours after drug exposure, corresponding to cell death. The remaining 12.5% of the cells showed little to no reduction in key Raman biomarkers, indicating their drug resistance. Furthermore, the patterned cell population showed a very similar response to etoposide as confluent cell cultures, as confirmed by flow cytometry. Finally, patterned cells were assessed with TUNEL assay for apoptosis due to DNA fragmentation after etoposide exposure. The results agree well with those from the Raman spectroscopy analysis. This combined biosensor-Raman platform provides a quick, simple way to assess cell responses to chemical and biological agents with high throughput and can be potentially used for a wide variety of biomedical applications such as pharmaceutical drug discovery, toxin tests, and biothreat detection.

Biochemical composition of body compartments during the reproductive cycle of the starfish Allostichaster capensis in Patagonia, Argentina

Allostichaster capensis (Perrier, 1875) (= inaequalis) is a fissiparous starfish inhabiting the South Atlantic Ocean coasts. On the Patagonian coast, it displays an annual sexual and asexual reproductive cycle. Fission is most frequent during the austral summer (November-January) and arm regeneration takes place during the rest of the year. In this article, seasonal changes in biochemical composition of body compartments are presented for a population of this fissiparous starfish in Bahia Kaiser, Golfo Nuevo, Chubut, Argentina, from June 2000 to May 2002. During the annual cycle, an inverse relationship between gonad and pyloric caeca indices suggests nutrient transfer. Biochemical analysis revealed that only lipids are translocated from pyloric caeca to gonads at the beginning of gametogenesis. Rev. Biol. Trop. 56 (Suppl. 3): 351-360. Epub 2009 January 05.

Effect of environmental factors and sex difference on physiological responses of the exotic red swamp crayfish, Procambarus clarkii, in Egypt.

he current study was conducted to investigate the effect of environmental factors and sex difference on the physiological status of the exotic red swamp crayfish (Procambarus clarkii) in Egypt along four successive seasons during the period from 2005 to 2006. Animals were collected from El-Mansourya canal at Giza governorate . Water and sediments were collected from three different aquatic habitats in order to determine the least polluted water quality region for collecting specimens used in the current study . These sites were: El-Mansourya canal (site I), El-Mouhit drain (site II) and Bany Magdoul canal (site III). During the four seasons, measurements of physicochemical characteristics of water and sediments revealed elevated annual concentrations for ammonia, nitrates, nitrites, in addition to high chlorosity in site II and heavy contamination with iron, copper, manganese, zinc and aluminum in site III; whereas site I was the least polluted and possesses the most transparent water with lowest electrical conductivity than the other sites. Lowest water temperature was recorded during winter and the highest one was during summer; while at the same season no wide difference has been found among the three habitats. Biochemical analysis of the main edible parts of crayfish inhabiting El-Mansourya canal (site I) revealed that males showed little rise in their muscle water content but females exhibited significant higher lipid content almost the year round. No marked changes were observed in the protein content in both sexes. Females also showed more glycogen accumulation in their abdominal muscles but lack statistical significance except during spring . In both sexes, highest levels for water content were reported during winter and for lipid during spring while for glycogen were during autumn . The lowest content for lipid was during autumn and for glycogen during winter for both sexes. The results indicate that seasonal changes in biochemical composition of edible parts of both sexes could reflect different physiological processes related to sex difference as an expression of animal adaptive response, an ecophysiological adaptation, to habitat quality and environmental conditions along the four successive seasons in Egypt.

Age-related degeneration of lumbar intervertebral discs in rabbits revealed by deuterium oxide-assisted MRI

Intervertebral disc (IVD) degeneration is associated with a loss of disc water content and change in biochemical composition of the disc. Rabbit is a frequently used model to evaluate the efficacy of therapeutics for disc degeneration. This study addresses whether rabbits undergo age-related disc degeneration, assessed using deuterium oxide-assisted magnetic resonance imaging (MRI) of the lumbar IVDs. The lumbar spines of adolescent, adult, and aged rabbits (6-36 months) were subjected to T2-weighted/short-tau inversion recovery (STIR) MRI scan along with water-deuterium oxide (H(2)O:D(2)O) dilutions. The total and maximum H(2)O:D(2)O index (HDi) of the lumbar IVDs were determined and compared between disc levels at different ages. Adolescent rabbit lumbar discs had similar total HDi, suggesting the hydration and biochemical composition was similar among the lumbar levels. With the use of H(2)O:D(2)O reference, the discs were shown to undergo continual decrease in signal with aging which non-calibrated measurement method could not reveal. The HDi decrease rate was higher at the caudal than cranial levels. This study provided in vivo evidence of age-related progressive disc degenerative change in rabbit lumbar discs, suggesting aged rabbits can be considered as a natural disc degeneration model in disc regeneration studies. However, it is important to select proper disc levels as intra-subject controls due to different rates of degenerative changes between caudal and cranial levels.

Developmental patterns of larval growth in the edible spider crab, Maja brachydactyla (Decapoda: Majidae)

The large edible spider crab Maja brachydactyla Balss, 1922, an overexploited coastal fishery resource in Galicia (NW Spain), is considered as a potential aquaculture candidate. Patterns of its larval growth were studied under controlled laboratory conditions (constant 18 ± 1 °C; 36‰ salinity; photoperiod ca. 12:12 h; lipid-enriched Artemia metanauplii provided as food). From hatching through complete larval development and metamorphosis to the first juvenile crab instar, changes in carapace size, dry weight (DW), ash content, elemental composition (carbon, hydrogen, nitrogen; CHN), and proximate biochemical composition (total proteins, lipids, carbohydrates; Pr, L, Ch) were measured in successive stages (zoea I, II, megalopa, crab I). Body size may be described as a linear function of the number of molting cycles, whereas the amounts of DW, CHN, Pr, L, and Ch per individual increased exponentially (3 to 9 fold). The highest growth rates were observed in L, C and H, the lowest in DW, Pr and N. As a consequence of these patterns, the C:N mass ratio as well as the fractions of L, C and H (in % of DW) increased significantly, while those of Pr and N decreased from 26% to 16% of DW. Throughout development, however, Pr remained the principal biochemical component of total DW. Positive correlations between biochemical and CHN data allow for estimates of Pr from N and of L from C values per individual. The patterns of larval growth observed in M. brachydactyla are, in general, similar to those previously described for other brachyuran crabs with a planktotrophic mode of larval development.

Comparative biochemical composition of ploidy groups of the lion-paw scallop (Nodipecten subnodosus Sowerby) supports the physiological hypothesis for the lack of advantage in triploid mollusc’s growth in food-rich environments

Induction of triploidy in aquatic organisms has increased worldwide in the last two decades, mostly because triploids have better growth than diploids. According to a physiological hypothesis, partial or total sterility of triploids allows the accumulation of reserves in muscle and other tissues instead of being transferred to the gonad. The present study analyzes lipid, protein, carbohydrate, and fatty acid levels in muscle and gonads of Nodipecten subnodosus triploids and diploids over 18 months from June 2001 to December 2002. An important increase in gonadosomatic index of diploids scallops was observed from May to June 2002 reaching the highest values in August. Such increase was not observed in triploid scallops. Changes in biochemical composition in female gonad were in general related to the accumulation of reserves during gonad development of diploid scallops. This accumulation was lower for triploid scallops, in accordance to their sterility, especially for carbohydrates and acylglycerides. Adductor muscle index as well as protein and carbohydrate levels in muscle increased in both ploidy groups during the reproductive period indicating no mobilization of reserves to sustain gonad development in both ploidy groups. These results partially support the physiological hypothesis on the advantage of triploids: in a rich food locality no mobilization of reserves is needed to sustain gametogenesis. This, together with a possible lower efficiency of energy assimilation at high food concentration for triploids, may be the reason for an apparent lack of superiority of N. subnodosus triploids in terms of adductor muscle growth. Only the levels of particular highly unsaturated fatty acids levels (namely 20:4n-6 and 20:5n-3) in muscle of diploid and triploid decreased during the reproductive period, indicating a possible transfer of selected fatty acids to gonads, even in triploids. The muscle of triploids has a slightly but significantly higher proportion of 22:6n-3 compared to diploids, which can have implications for the nutritional and commercial value of triploid adductor muscle.

Changes in the hemolymph and fat body metabolites of Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) parasitized by Cotesia flavipes (Cameron) (Hymenoptera: Braconidae)

The koinobiont Cotesia flavipes responds to and is influenced by biochemical changes in the host hemolymph composition, Diatraea saccharalis. Changes in the composition of macronutrients may occur due to the hosts own development or by changes induced after parasitization. These changes occur to facilitate parasitoid invasion and to make the host internal environment suitable to parasitoid immature development. Therefore, changes in the availability of stored and circulating nutrients may correlate with the nutritional requirements of specific parasitoid immature stages. In here, we describe changes in the biochemical composition of parasitized and control larvae at different stages of parasitoid development to gain information on C. flavipes host regulation and on its quantitative immature nutritional requirements. Total proteins, lipids and carbohydrates free in the hemolymph or stored in host fat bodies, and the SDS–PAGE protein profile of the hemolymph were evaluated in control and parasitized 6th instar during the whole parasitoid development. Changes in the total protein available in the host hemolymph were detected soon after parasitization, but carbohydrate and lipids were observed to differ only towards parasitoid larvae egression. Although C. flavipes affected the availability of all macronutrients observed in the host hemolymph, lipids and proteins stored in the host fat bodies were unaffected. However, carbohydrate concentration at the end of parasitoid larval development was much lower in parasitized than in control larvae at the same stage of development. SDS–PAGE analysis indicated C. flavipes up-regulated two host proteins (125 and 48kDa) and released two parasitism-specific proteins towards the end of parasitoid larval development. We provide a discussion on the role these changes may have on the process of host regulation and their possible requirement to sustain parasitoid development.