Protein Reserves Research Articles

Estudios de cepas de Ascosphaera apis aisladas de polenes comerciales de diferentes provincias españolas y su capacidad de producción enzimática

Ascosphaera apis es un hongo patógeno de larvas de abejas Apis mellifera que provoca la enfermedad cría yesificada, la cual ocasiona serios daños a las colmenas, y llega a producir graves pérdidas económicas. La enfermedad suele ser recurrente durante el periodo de lluvias y temperaturas bajas, pero también existen otros factores que predisponen a la colonia a enfermarse, como la falta de reservas proteicas, la mala ventilación dentro de la colmena y colmenas débiles, especialmente en aquellas donde no hay un uso adecuado de antimicrobianos. En este trabajo se aislaron seis cepas del hongo de pólenes comerciales proveniente de cuatro provincias españolas, que fueron conservados durante 48 meses, las mismas fueron identificadas genéticamente utilizando las regiones ITS (internal transcription espace) que codifican para ARNr 5.8S, para comprobar su viabilidad se procedió a realizar un screening enzimático in vitro de la capacidad de secreción de quitinasas y proteasas en medios convencionales, se comprobó que todas las cepas fueron viables a 30ºC y en condiciones de microaerofilia, además se demostró que las cepa están relacionadas filogenéticamente, alejadas de otros países, lo que estaría evidenciando que las esporas son transportadas entre provincias españolas. Este trabajo trae una aproximación a la viabilidad de las esporas del hongo A. apis en pólenes comerciales, para ampliar las medidas sanitarias y controlar el polen usado en la alimentación de las colmenas cuando este es escaso.

The Conservation of VIT1-Dependent Iron Distribution in Seeds.

One third of people suffer from anemia, with iron (Fe) deficiency being the most common reason. The human diet includes seeds of staple crops, which contain Fe that is poorly bioavailable. One reason for low bioavailability is that these seeds store Fe in cellular compartments that also contain antinutrients, such as phytate. Thus, several studies have focused on decreasing phytate concentrations. In theory, as an alternative approach, Fe reserves might be directed to cellular compartments that are free of phytate, such as plastids. However, it is not known if seed plastid can represent a major Fe storage compartment in nature. To discover distinct types of Fe storage in nature, we investigated metal localizations in the seeds of more than twenty species using histochemical or X-ray based techniques. Results showed that in Rosids, the largest clade of eudicots, Fe reserves were primarily confined to the embryo of the seeds. Furthermore, inside the embryos, Fe accumulated specifically in the endodermal cell layer, a well-known feature that is mediated by VACUOLAR IRON TRANSPORTER1 (VIT1) in model plant Arabidopsis thaliana. In rice, Fe enrichment is lost around the provasculature in the mutants of VIT1 orthologs. Finally, in Carica papaya, Fe accumulated in numerous organelles resembling plastids; however, these organelles accumulated reserve proteins but not ferritin, failing to prove to be plastids. By investigating Fe distribution in distinct plant lineages, this study failed to discover distinct Fe storage patterns that can be useful for biofortification. However, it revealed Fe enrichment is widely conserved in the endodermal cell layer in a VIT1-dependent manner in the plant kingdom.

Seed position and influences on Caesalpinia pulcherrima germination and reserve proteins

Caesalpinia pulcherrima has diverse uses in the world, including ornamental and landscape characteristics, but there is a great disparity of germination during the time of seedlings production, being this factor attributed to the position of the seeds in fruits. This study aimed to evaluate some germinative aspects and concentration of reserve proteins in C. pulcherrima seeds in the function of its position in fruits. The work was carried out in greenhouse, in a completely random experimental design, with five seed position in the pod, based on the distance from seed to the peduncle (P1 - distal, P2 - distal/median, P3 - median, P4 -proximal/ median, P5 - proximal). Eight replicates with eight seeds each, were sowed to germinate for 21 days in expanded polystyrene trays filled with substrate. The percentage, speed index, average germination time and 50% germination time of the plantlets were evaluated. The reserve proteins (albumin, globulin, prolamin and glutelin) contents were also determined. There was influence of the position of the seed in the fruit on germination and reserve proteins contents. The proximal/median position showed excellent results, having correlations of albumin, globulin and glutelin concentrations with some germinative parameters. Therefore, the use of proximal/median position of the seeds is recommended for C. pulcherrima propagation.

Effects of starvation and stocking density on the physiology of the male of the southern king crab Lithodes santolla

The southern king crab (SKC) Lithodes santolla is an important commercial species in southern South America. There is a greater need for availability of fresh and live crabs during the season of highest demand in summer (mainly December and January). Thus, this study aimed to determine the effects of starvation and stocking densities on the physiological status of male SKC to know whether SKC can be stocked after they are fished. To assess the effects of starvation, crabs were assigned to two experimental groups: the Laboratory group (in which crabs were either fed daily (controls), fed every 15 days, or starved and the Sea group (in which crabs were either fed every 15 days or starved). Starved crabs showed a very slight mass reduction (<5%), glycogen depletion from the midgut gland (when kept at sea), lipid peroxidation reduction in both the muscle and the midgut gland, and micro-structural alterations of the midgut gland. Starved crabs were then analyzed at three stocking density levels: low (35 crabs m−3), medium (69 crabs m−3), and high (115 crabs m−3) for 30 days. In this experiment, we found, at all densities, a decreased weight of the midgut gland, a low condition index, decreased lipase activity, glycogen reduction, increased protein reserves, and lipid peroxidation reduction, and decreased lipid levels at low and medium densities. The muscle showed, at all densities, an increased protein oxidation and a decrease in the RNA:DNA ratio. Our results suggest that SKC can tolerate relatively high stocking densities, have low mortality, and are able to endure 60 days of food deprivation without lowering their flesh yield. This would allow marketing crabs alive off-season.

Extreme climatic variability during migration invokes physiological and dietary plasticity among spring migrating ducks

Environmental stochasticity encountered during migration can have negative consequences for individuals and population demographics through direct reductions in survival or cross-seasonal impacts. We took advantage of substantial interannual variation in spring migration conditions over a 4 year field study to examine physiological and dietary variation among two species of migrant ducks. We collected female Lesser Scaup (Aythya affinis (Eyton, 1838)) and Blue-winged Teal (Spatula discors (Linnaeus, 1766)) during spring migration and measured lipid and protein reserves, an index of recent lipid metabolism based on concentrations of lipid metabolites in plasma, and diets. We documented systematic interannual variation among these metrics in both species, contrasting primarily the warmest, earliest spring and the coldest, latest spring. Lesser Scaup had reduced lipid and protein reserves and consumed less energy-rich prey during the coldest and latest spring but showed no interannual variation in the index of lipid metabolism. Blue-winged Teal similarly had reduced protein reserves in the cold, late spring but maintained constant lipid reserves among years, likely facilitated by increased consumption of energy-rich seeds reflected in diets and lipid metabolism. Our results reveal impacts of environmental stochasticity on migrants and suggest that recruitment may be impacted by variable conditions encountered during migration during extreme weather events.

The ovarian germinal reserve and apoptosis-related proteins in the infant and adolescent human ovary

BackgroundNormal pubertal ovary displays all stages of follicular development and a biased BAX/BCL2 protein ratio in favor of pro-apoptotic BAX protein comparable to the adult ovary. However, adolescents suffering malignant extra-gonadal disease show a limited follicle development after cytotoxic drug treatment and a reduced capacity of in vitro follicle growth. We evaluated the expression of pro- and anti-apoptotic members of the BCL2 gene family, the FAS/FAS-L proteins from the extrinsic apoptosis pathway, the germ-cell-specific marker VASA, the pluripotency marker OCT3/4, and markers of early and late apoptosis in the ovary of pubertal patients with malignant extra-gonadal disease, which received or not pre-surgery chemotherapy, entering a cryopreservation program.ResultsOvarian biopsies from 12 adolescent girls were screened for follicle count and expression of VASA, OCT3/4, BAX, BCL2, MCL1L and S, cleaved-BID, FAS/FAS-L and CASPASE 3 through immunohistochemistry, western blot and RT-PCR. All stages of folliculogenesis, from primordial to antral follicle, were present in all 12 patients analyzed. VASA and most of the screened apoptosis-related genes showed a pattern of immune-expression comparable to that previously reported. OCT3/4 showed a cytoplasmic localization in the great majority of the primordial follicles; however, in some cases the localization was nuclear. In addition, OCT3/4B showed a significant reduction compared to OCT3/4A. Unexpectedly, BCL2 was detected at all stages of folliculogenesis, associated to the Balbiani’s body in the primordial follicles, regardless of whether patients had or had not received chemotherapy, ruling out the possibility that its expression is a protective response to chemotherapy.ConclusionsThese findings reveal new information on the morphological status of the follicular reserve and the expression of apoptosis-related genes in histologically normal adolescent ovary from patients undergoing extragonadal cancer. The unexpected expression of apoptosis-inhibiting BCL2 protein, both in patients that had or had not received chemotherapy, opens a new avenue for thorough investigations. Moreover, the nuclear localization of OCT3/4 protein in primordial follicle-enclosed oocytes suggests a possible increased activity of ovarian stem cells in response to chemotherapy and/or extragonadal cancer. This new information can be essential for a better managing of in vitro culture of follicles that can be removed by filtration from preserved ovarian tissue, especially in girls that entered a cryopreservation program.

Determination of the united quality latent index of adaptability (UQLIA) and contribution of some environmental parameters to it for Deschampsia antarctica populations, Galindez island (Maritime Antarctic) season 2017/2018

The purpose of our work has been to determine the indicator of complex adaptability — the United Quality Latent Index of Adaptability (UQLIA) for the experimental populations of Deschampsia antarctica É. Desv. and study the contribution to it of some environmental factors such as the near soil surface temperature and organogens content. Materials and methods. The determination of UQLIA was based on a pairwise comparison of the differences between investigated parameters of populations by mathematical regression techniques. The soil surface temperature was measured by loggers installed near plants in each locus during April 2017 – April 2018. Results and conclusions. Temperature fluctuations were described during December 2017 – February 2018 for twelve experimental populations of D. antarctica and one control fragment of moss turf subformation from Galindez Island. Significant variations in average daily near surface temperature were observed during the study period between populations, especially in December and January. The UQLIA of D. antarctica for this season was calculated on the basis of the projective cover, biometric indices of generative plants and the content of protective and reserve proteins in seeds for the eleven populations. The values of the United Soil Surface Temperature Influence Index (UTII) for the season summer months and the United Organogens Content in Soil Influence Index (UOCSII) have been calculated for the individual parameters of D. antarctica plants adaptability. The reliable contribution of UTII to ULIA has been shown for December and January, at the moment of the greatest variation of soil surface temperature. UOCSII provided a reliable contribution to the ULIA only in the amount of UTII. Keywords: Deschampsia antarctica, United Quality Latent Index of Adaptability (UQLIA), contribution of soil surface temperature and organogens content to complex adaptability.

The effect of temperature on Triclosan and Lead exposed mussels.

Interest on the effects of emerging contaminants over aquatic organisms has increased in the last years. Nonetheless, the toxic action of classical natural and anthropogenically-driven metals has also to be monitored, especially because they reflect real environmental situations. For that, in the present study we focused on the effects on the marine mussel Mytilus galloprovincialis of the personal care product Triclosan (TCS) and Lead (Pb), as toxic metal, under separate and co-exposure situations at environmentally relevant concentrations: TCS (1 μg/L) and Pb (50 μg/L). The consideration of an additional factor such as an increase in ambient temperature was also included to provide a forecasted scenario of climate change: from the ambient temperature at actual conditions (17 °C) to a predicted warming situation (22 °C). Water chemical characterization and some physical properties and bioaccumulation of TCS and Pb in mussels at the end of the experiment (28 days) was considered. The parameters followed up comprise the energy related system production (electron transport system) and glycogen and protein reserves. Antioxidant enzymatic defences towards reactive oxygen species (ROS) and the consequences of ROS damage over endogenous lipids (LPO) and proteins (PC). Overall the results suggested only particular responses to chemical exposures at 17 °C whereas at 22 °C the detoxification machinery was set up and this prevented the occurrence of LPO. Nonetheless, PC formation occurred under Pb and TCS + Pb co-exposure at the highest temperature. Due to the complexity of the study: 4 chemical conditions, 2 temperatures and 10 biomarkers considered, a principal component ordination (PCO) analysis was included. The results of this integrative analysis confirmed a clear effect of the temperature, more responsiveness to drugs at 22 °C and in all likelihood due to Pb presence.

Dynamics of Storage Materials in Cotyledon During Cocoa Seed Germination

Degradation of carbohydrate, protein and lipid food reserves occurs in the seed germination process to produce energy for germination and further growing. This study aimed to determine dynamics the content of protein, carbohydrates, and lipid in cotyledon of seed clon i.e. Sca 6, RCC 70, RCC 71 and KKM 22 during germination. The experiment used completely randomized design consisted of four replications with 4 treatments. In each cocoa germination phases i.e. before germination, phase II (bend/curved phase), cotyledon emergence, leaves emergence and fall of cotyledon from the sprouts. This observation were water content, ash content, lipid, soluble protein, total protein and carbohydrate content. The results of the experiment showed that during germination, there was an increase of water content in cotyledon from the bend phase to the leaf emergence and decrease in the phase of fall of cotyledon The highest water content was observed in the leaf emergence phase as high as 69.42%. The content of ash content, dissolved protein, total protein and carbohydrates in cotyledon fluctuated during the bend phase until the leaf emergence and increased in the phase of fal of cotyledon. ipid content has decreased from the bend phase until the fall of cotyledons. Carbohydrate levels have increased from the bend phase to the fall of cotyledons. The speed of degradation procces of seed stored material (water, lipid, protein and carbohydrate content) during germination is affected by differences in seed clones. The Scavina 6 and KKM 22 clones entered the bend phase and the realease of cotyledon.

The influence of temperature on the effects induced by Triclosan and Diclofenac in mussels

Little is known about the consequences of exposure to pharmaceuticals and personal care products (PPCPs) in elevated temperatures associated with climate change. To increase the knowledge on this topic, Mytilus galloprovincialis mussels were exposed to 1.0 μg/L of either the antimicrobial Triclosan (TCS) or the anti-inflammatory drug Diclofenac (DIC), at control (17 °C) and 4 °C raised (21 °C) temperatures for 28 days. Triclosan and DIC concentrations in the water and tissues were subsequently measured and related to biomarker responses including: energy metabolism (electron transport system (ETS) activity, glycogen and protein reserves), oxidative stress markers, glutathione balance between the reduced and the oxidised form (GSH/GSSG), and damage to proteins and lipids. Mussels responded to the increase in temperature and drug exposure by lowering their metabolic rate (decreased ETS), increasing their endogenous reserves and antioxidant defences, thus preventing oxidative stress damage, with the exception of DIC exposure at the higher temperature. In all cases, GSH/GSSG ratio was reduced in detriment of the antioxidant form at both PPCPs exposures and elevated temperature with no additive effect due to combined stressors. Overall, either drug exposure or increased temperature could compromise the ability of mussels to withstand further insults.

Impact of Coronary Artery Bypass Grafting on Muscle Mass Reduction on the 7th Postoperative Day

Abstract Background: Ischemic heart failure is a chronic and degenerative disease with high morbidity and mortality in the world. Coronary artery bypass grafting is indicated as elective treatment and may cause a catabolic state that depletes energy reserves. Data on body composition evaluation in the postoperative period of major cardiac surgery are limited. Objective: To evaluate the influence of elective coronary artery bypass grafting on body composition on the seventh postoperative day of patients with ischemic heart failure. Methods: A cross-sectional study was carried out in which eighteen volunteers with New York Heart Association Class II and III heart failure underwent coronary artery bypass grafting. The energy and protein reserves of the participants were evaluated by anthropometry in the preoperative and on the seventh postoperative day. Paired t-Test or Mann-Whitney test was used if applicable. A significance level was considered at p value < 0.05. Results: A significant loss of muscle mass was observed through the reduction of arm muscle circumference after surgery (4.2%, p 0.007). Major surgery causes hypermetabolic state and systemic inflammatory stimulus, due to the release of hormones and cytokines that may justify the observed loss of muscle mass. Conclusion: Coronary artery bypass grafting had an impact on muscle mass reduction seven days after surgery in patients with ischemic heart failure.

E2FA and E2FB transcription factors coordinate cell proliferation with seed maturation.

ABSTRACTThe E2F transcription factors and the RETINOBLASTOMA-RELATED repressor protein are principal regulators coordinating cell proliferation with differentiation, but their role during seed development is little understood. We show that in fully developed Arabidopsis thaliana embryos, cell number was not affected either in single or double mutants for the activator-type E2FA and E2FB. Accordingly, these E2Fs are only partially required for the expression of cell cycle genes. In contrast, the expression of key seed maturation genes LEAFY COTYLEDON 1/2 (LEC1/2), ABSCISIC ACID INSENSITIVE 3, FUSCA 3 and WRINKLED 1 is upregulated in the e2fab double mutant embryo. In accordance, E2FA directly regulates LEC2, and mutation at the consensus E2F-binding site in the LEC2 promoter de-represses its activity during the proliferative stage of seed development. In addition, the major seed storage reserve proteins, 12S globulin and 2S albumin, became prematurely accumulated at the proliferating phase of seed development in the e2fab double mutant. Our findings reveal a repressor function of the activator E2Fs to restrict the seed maturation programme until the cell proliferation phase is completed.

Evaluation of physiological stress and nutritional deficiency related to cannibalism in early paralarvae of Patagonian red octopus Enteroctopus megalocyathus

Patagonian red octopus Enteroctopus megalocyathus is one of the two octopuses' species of great commercial importance in Chile. At the present time, the life cycle of this species in captivity has been closed at experimental level; however, high mortalities at the early paralarvae stage are a limiting factor for attaining sustainable production. Cannibalism has been identified as one of the main mortality causes at the early paralarvae rearing. Stress has been proposed as an important cause of cannibalism in cephalopods. Likewise, nutritional deficiency has been suggested as a potential cause to onset cannibalism. However, neither of both factors has been directly assessed in cephalopod paralarvae. In the present study, we aimed to elucidate if physiological stress due to a food shortage and/or to a high rearing density of paralarvae trigger cannibalism in E. megalocyathus. An experiment was carried out with newly hatched paralarvae, under conditions that trigger cannibalism with densities of 10 and 15 paralarvae L−1 combined with two measures of prey availability: 0 and 2 prey paralarva−1 day−1. Paralarvae alone in the aquarium fed ad libitum was used as a control to avoid cannibalism. Nutritional status was assessed as the total protein and energy content per paralarvae; and the 70 kD heat shock protein (HSP70) transcript level was used as a bioindicator of physiological stress, documented as a suitable stress biomarker for cephalopods. No differences were observed between the treatments and control in the absolute protein levels and energy content. There was a strong induction in HSP70 transcriptional level when high density and prey availability where combined, proving that there are only a few paralarvae rearing combinations that cause critical stress and trigger HSP70 transcription. In experimental conditions, nutritional status indicators showed that early paralarvae, with similar reserves of protein and energy, exhibited cannibalism. Results suggest that mortality as well as cannibalism is associated with competition for prey and with nutritional and energy imbalance due to food shortage that determines the expression of the related stress gene.

Methyl eugenol effects on Bactrocera dorsalis male total body protein, reproductive organs and ejaculate

AbstractMethyl eugenol (ME) and inclusion of protein into the adult diet increase the mating competitiveness of the Oriental fruit fly, Bactrocera dorsalis (Hendel). Exposing males to ME or protein is a promising post‐teneral treatment for males being released in the sterile insect technique (SIT). However, the effect of this post‐teneral treatment on male reproductive organs or the male ejaculate is unknown. During mating, males transfer sperm and accessory gland products (AGPs) to females and these compounds are reported to modulate female sexual inhibition. We studied the impact of male exposure to ME and a yeast hydrolysate (YH) diet on the protein reserves of males, male reproductive organ size, and the male ejaculate through sperm and AGPs. We show that males exposed to ME regardless of access to YH accumulated a greater amount of whole body protein. Males fed on YH also had increased total body protein and had bigger reproductive organs than YH‐deprived males, but no apparent effect of ME exposure was observed on reproductive organ size. Females stored less sperm when mated with males fed on YH and ME compared to males not fed on ME. YH and ME had no effect on male AGPs. Females injected with AGPs of males fed on YH and exposed to ME were just as likely to mate as females injected with AGPs of non‐treated males. However, females injected with AGPs of males exposed to ME mated faster than females injected with AGPs of non‐exposed males. We conclude that while exposure to ME increases male copulatory success and protein reserves in the male body, there seem to be some potential trade‐offs such as lower sperm stored by females. We discuss our results in terms of pre‐release protocols that may be used for B. dorsalis in SIT application.

Body Protein Reserves Sustain Maternal Performance in Early Lactation but Dietary Protein Is Necessary to Maintain Performance and Immune Responses to Nippostrongylus brasiliensis in Lactating Rats

It has been shown that dietary protein supplementation during lactation boosts immunity in Nippostrongylus brasiliensis-infected periparturient rats. It is not known whether body protein reserves accumulated during gestation have a similar effect during lactation. This study aimed to quantify the impact of body protein reserves and dietary protein supplementation on maternal performance and immune responses to N. brasiliensis during lactation. Multiparous female Sprague-Dawley rats were administered a primary infection of N. brasiliensis before mating and were restriction-fed either 60 g [low-protein diet gestation (Lge)] or 210 g [high-protein diet gestation (Hge)] crude protein (CP) per kilogram of dry matter (DM) until parturition. From parturition onward, dams were restriction-fed either 100 g [low-protein diet lactation (Lla)] or 300 g [high-protein diet lactation (Hla)] CP per kilogram of DM, generating 4 different dietary treatments. A subset of rats was sampled before parturition; postparturition, dams were secondarily infected with N. brasiliensis and samples were collected at days 5 and 11 postparturition. Maternal performance until parturition, as measured by pup weight, was better in Hge rats than in Lge rats [Lge: 4.84 g; Hge: 6.15 g; standard error of the difference (SED): 0.19]. On day 11, pup weights of dams with reduced protein reserves fed protein during lactation (Lge-Hla; 20.28 g) were higher than their counterparts from Hge-Lla dams (17.88 g; SED: 0.92). Worm counts were significantly different between Lge-Lla-fed (253; 95% CI: 124, 382) and Hge-Hla-fed (87; 95% CI: 22, 104) dams on day 11 (P=0.024). The expression of splenic interleukin 13 (Il13) and arachidonate 15-lipoxygenase (Alox15) was significantly higher (P<0.05) in Hge-Hla dams compared with Lge-Lla dams on day 5. Although protein reserves were adequate to maintain maternal performance in the early stage of lactation in dams infected with N. brasiliensis, they were not adequate to maintain maternal performance and effective immune responses at later stages. Dietary protein supplementation was required to achieve this.

Dietary management and supplementation with branched-chain amino acids in cirrhosis of the liver.

One of the most important characteristics of malnutrition is the loss of muscle mass and the severe depletion of the protein reserve, secondarily affecting energy metabolism. That impacts nutritional status and the progression of disease-related complications. Nutritional treatment is one of the main factors in the comprehensive management of those patients. Achieving adequate energy intake that provides the macronutrients and micronutrients necessary to prevent or correct malnutrition is attempted through dietary measures. ESPEN, the European Society for Clinical Nutrition and Metabolism, recommends a caloric intake of 30-40kcal/kg/day, in which carbohydrates provide 45-60% of the daily energy intake and proteins supply 1.0-1.5g/kg/day. The remaining portion of the total energy expenditure should be covered by lipids. The administration of branched-chain amino acids has been shown to be beneficial not only in counteracting malnutrition, but also as a coadjuvant treatment in specific complications, thus playing a favorable role in outcome and quality of life. Therefore, branched-chain amino acids should be considered part of nutritional treatment in patients with advanced stages of cirrhosis of the liver, particularly in the presence of complications.

Spring temperature, migration chronology, and nutrient allocation to eggs in three species of arctic-nesting geese: Implications for resilience to climate warming.

The macronutrients that Arctic herbivores invest in their offspring are derived from endogenous reserves of fat and protein (capital) that females build prior to the period of investment or from foods they consume concurrently with investment (income). The relative contribution from each source can be influenced by temporal and environmental constraints on a female's ability to forage on Arctic breeding areas. Warming temperatures and advancing Arctic phenology may alter those constraints. From 2011 to 2014, we examined relationships among spring temperature, timing of migration and reproduction, and the sources of nutrients females deposited in eggs for three sympatric species of geese that nested in northern Alaska. Compared to lesser snow geese (Anser caerulescens caerulescens) and greater white-fronted geese (Anser albifrons frontalis), black brant (Branta bernicla nigricans) were more likely to initiate follicle development during migration, resulting in fewer days between their arrival in the Arctic and the onset of incubation and requiring a relatively greater capital investment in eggs. Delaying follicle development until after their arrival in the Arctic provided snow geese and white-fronted geese an opportunity to forage near their nesting area and to deposit exogenous nutrients in eggs. With warmer spring temperatures, brant invested more capital in eggs, but snow geese invested less capital. Brant likely used capital to meet costs associated with earlier onset of follicle development when phenology was advanced, whereas snow geese used capital to compensate for poor foraging conditions during colder Arctic springs. Global warming is likely to reduce the quality of lower latitude marine habitats where brant acquire endogenous reserves and advancing Arctic phenology may increase their reliance on those reserves during reproduction. Near-term warming in northern Alaska may improve foraging conditions and favor the reproductive strategies of some herbivores such as snow geese and white-fronted geese that mainly invest Arctic nutrients in their offspring.

Azadirachtin impairs egg production in Atta sexdens leaf-cutting ant queens

Leaf-cutting ants are important pests of forests and agricultural crops in the Neotropical region. Atta sexdens colonies can be composed of thousands of individuals, which form a highly complex society with a single reproductive queen. Successful control of this species is achieved only if the queen is affected. Few data are available on the lethal or sublethal effects of toxic compounds on leaf-cutting ant queens. Azadirachtin has been claimed as an effective biopesticide for insect control, but its action on leaf-cutting ants has been little explored. This study shows that azadirachtin affects oviposition in A. sexdens queens, impairing egg development by decreasing protein reserves. Azadirachtin inhibits the synthesis of vitellogenin, the major yolk protein precursor. The negative effects of azadirachtin on the reproduction of leaf-cutting ant queens suggest a potential use for the control of these insects.

Activities of Carbon and Nitrogen Metabolism Enzymes of Sorghum (Sorghum bicolor L. Moench) During Seed Development

Carbon and nitrogen metabolism pathways are regulated by complex mechanisms in order to optimize growth and development of plants and play a major role in determining the amount of protein stored in cereal grains. This study was conducted to contribute to determine the roles of certain key enzymes of carbon and nitrogen metabolism in developing sorghum seeds. Sorghum bicolor (L.) Moench was grown in a growth chamber. Seeds were harvested at various stages of development and used to the analysis of certain key enzymes of carbon and nitrogen metabolism. The results were subjected to stastistical analysis using one-way analysis of variance (ANOVA) followed by the Tukey test. The results showed that during the seed development the highest activities of glutamine synthetase, glutamate dehydrogenase, phosphoenolpyruvate carboxylase, malate dehydrogenase, isocitrate dehydrogenase, and aspartate aminotransferase were detected at the time of maximum seed filling stages (15-20 DAP). Hence, higher activities of these enzymes at the time of maximum seed-filling stages could be effectively linked to amino acids synthesis and therefore the deposition of protein reserves.

Influence of rearing-water temperature on life stages\u2019 vector attributes, distribution and utilisation of metabolic reserves in Culex quinquefasciatus (Diptera: Culicidae): implications for disease transmission and vector control

BackgroundThis study aims at determining the effects of rearing water temperature on immature development, adult vectorial attributes and teneral accumulation in Culex quinquefasciatus (Cx. quinquefasciatus) mosquitoes. Immature life stages of the species were reared (to adulthood) in water media with temperature regimens of 28, 30, 32 and 34 °C generated and maintained by digital electrical thermostats. Immature and adult vectorial attributes (i.e. duration of development, growth rates, immature and adult survivorship, emergence rates and adult longevity), and rates of accumulation, distribution and utilisation (for pupation and eclosion) of teneral reserve (lipid, glucose, glycogen and protein) by life stages of the species were determined.ResultResults revealed significant negative effects of temperature increase on all parameters measured. Among these, only rate of larval growth (range = 0.0589 ± 0.0017 to 0.0930 ± 0.0003 mg/day) increased with temperature rise; others reduced with rise in temperature. Total immature duration (9.75 ± 0.09 to 6.43 ± 0.11 days), immature survivorship (94.01 ± 0.18 to 73.26 ± 3.72%), total emergent adults (72.00 ± 2.14 to 14.50 ± 2.67 adults/100 larvae), percentage of emergence, adult daily survivorship (76.86 ± 1.87 to 63.66 ± 0.18%) and post-emergence longevity (23.91 ± 2.97 to 16.90 ± 1.97 days) reduced with increase in temperature. Accumulation of teneral components increased across larval instars, but decreased with temperature rise and at metamorphosis (pupation and eclosion). Immature composition for lipid, glucose, glycogen and protein ranged, respectively, from 9.79 ± 1.05 to 20.07 ± 0.33, 8.49 ± 0.44 to 14.33 ± 0.44, 28.19 ± 2.34 to 42.87 ± 0.12 and 24.11 ± 0.71 to 35.55 ± 0.15 μg/mosquito. While, adult values for these ranged from 7.53 ± 0.40 to 20.66 ± 0.61, 7.45 ± 0.87 to 13.86 ± 0.83, 22.63 ± 0.85 to 33.64 ± 0.79, and 17.81 ± 1.02 to 31.45 ± 1.40 μg/mosquito, respectively. Glycogen and protein had the highest rates of accumulation, while metabolic reserves utilised for pupation and eclosion varied significantly with temperature change.ConclusionThis study revealed significant effects of temperature on the entomological parameters measured. Vectorial fitness indices, such as duration of immature development and survivorship, emergence rates, adult survivorship and longevity, and teneral accumulation and utilisation, tend to reduce with increase in temperature, while larval growth rates increased with temperature rise. The information generated is vital for developing temperature-based models and life-stage control strategies.