Protein Reserves Research Articles

Inorganic Contaminants, Nutrient Reserves and Molt Intensity in Autumn Migrant Red-Necked Grebes (Podiceps grisegena) at Georgian Bay.

Red-necked grebes (Podiceps grisegena) are piscivorous waterbirds that breed on freshwater lakes in northwestern Canada and stop-over at the Great Lakes during autumn migration to molt feathers and replenish lipid and protein reserves. The objectives of this study were to (1) describe concentrations of, and correlations among, inorganic contaminants in a sample of autumn migrant red-necked grebes from the Great Lakes, (2) compare concentrations of inorganic contaminants to those in autumn migrant common loons from Schummer et al. (Arch Environ Contam Toxicol 62:704, 2011a), (3) evaluate if the inorganic elements are negatively associated with lipid and protein reserves, and (4) determine if nutrient reserves and molt intensity were correlated. None of the 14 contaminants analyzed were above threshold levels known to cause acute health problems in piscivorous birds. Body masses of plucked birds were within the normal reported range. Lipid reserves varied positively with hepatic concentrations of arsenic, copper, iron, nickel, lead, and selenium and negatively with mercury and magnesium. Protein reserves variety negatively with hepatic concentrations of arsenic, calcium, nickel, lead, and zinc and positively with aluminum, cadmium, and iron. A negative correlation was observed between chest molt and lipid reserves but not between nutrient reserves and other feather tracts. The relationships between lipid reserves and both mercury and selenium were consistent with current research on other piscivorous waterbirds at the Great Lakes and justify continued work to determine interactions of these contaminants in waterbirds that breed, stage, and winter in the region.

Multiple factors contribute to anautogenous reproduction by the mosquito Aedes aegypti

Aedes aegypti is an anautogenous mosquito that must blood feed on a vertebrate host to produce and lay a clutch of eggs. The rockpool mosquito, Georgecraigius atropalpus, is related to A. aegypti but is a facultatively autogenous species that produces its first clutch of eggs shortly after emerging without blood feeding. Consumption of a blood meal by A. aegypti triggers the release of ovary ecdysteroidogenic hormone (OEH) and insulin-like peptide 3 (ILP3) from the brain, which stimulate egg formation. OEH and ILP3 also stimulate egg formation in G. atropalpus but are released at eclosion independently of blood feeding. These results collectively suggest that blood meal dependent release of OEH and ILP3 is one factor that prevents A. aegypti from reproducing autogenously. Here, we examined two other factors that potentially inhibit autogeny in A. aegypti: teneral nutrient reserves and the ability of OEH and ILP3 to stimulate egg formation in the absence of blood feeding. Measures of nutrient reserves showed that newly emerged A. aegypti females had similar wet weights but significantly lower protein and glycogen reserves than G. atropalpus females when larvae were reared under identical conditions. OEH stimulated non-blood fed A. aegypti females to produce ecdysteroid hormone and package yolk into oocytes more strongly than ILP3. OEH also reduced host seeking and blood feeding behavior, yet females produced few mature eggs. Overall, our results indicate that multiple factors prevent A. aegypti from reproducing autogenously.

Nutrition status of HIV+ children in Botswana

Purpose – Identifying and addressing poor nutritional status in school-aged children is often not prioritized relative to HIV/AIDS treatment. The purpose of this paper is to elucidate the benefits of integrating nutrition (assessment and culturally acceptable food supplement intervention) in the treatment strategy for this target group. Design/methodology/approach – The authors conducted a randomized, double blind pre-/post-intervention trial with 201 HIV-positive children (six to 15 years) in Botswana. Eligibility included CD4 cell counts < 700/mm3 (a marker for the severity of HIV infection), documented treatment with antiretroviral (ARV) drugs, and no reported evidence of taking supplemental food products with one or more added nutrients in the six-month period prior to the study. The intervention (12 months) consisted of two food supplements for ethical reason, one with a higher protein content, bean (bean-sorghum based) group (n=97) and a cereal (sorghum) group (n=104) both of which contained added energy- and micro- nutrients. Anthropometric and biochemical nutritional status indicators (stunting, wasting, underweight, skinfolds for fat and muscle protein reserves, and hemoglobin levels) were compared within and between the bean and the cereal groups pre- and post-intervention separately for children six to nine years and ten to 15 years. Findings – Older children (ten to 15 years) fared worse overall compared to those who were younger (six to nine years) children in anthropometric and protein status indicators both at baseline and post-intervention. Among children six to nine years, the mid arm circumference and blood hemoglobin levels improved significantly in both the bean and cereal groups (p < 0.01 and p < 0.05, respectively). Although the BMI for age z-score and the triceps skinfold decreased significantly in the bean group, the post-intervention subscapular skinfold (fat stores) was significantly higher for the bean group compared to the cereal group (p < 0.05). Among children ten to 15 years, both the bean and the cereal groups also showed improvement in mid arm circumference (p < 0.001), but only those in the bean group showed improvement in hemoglobin (p < 0.01) post-intervention. Originality/value – Similar significant nutritional status findings and trends were found for both food interventions and age within group pre- vs post-comparisons, except hemoglobin in the older children. Post-intervention hemoglobin levels for the type food supplement was higher for the “bean” vs the “cereal” food in the younger age group. The fact that all children, but especially those who were older were in poor nutritional status supports the need for nutrition intervention in conjunction with ARV treatment in children with HIV/AIDS, perhaps using a scaled up future approach to enhance desired outcomes.

Regulatory factors controlling muscle mass: Competition between innate immune function and anabolic signals in regulation of atrogin-1 in Atlantic salmon.

Atrogin-1 is a conserved ubiquitin E3 ligase that is central to the early stages of skeletal and cardiac muscle wasting and degradation following starvation and inflammatory diseases. The control of protein turnover is different between endothermic and ectothermic animals reflecting the body energy requirements. Here we have characterised the promoter of the atrogin-1 gene in a phylogenetically diverse group of vertebrates and show conserved FOXO elements are present in all species examined. We have examined the gene expression responses in primary muscle cell culture to key immune modulators (IL-1β, interferon type 1 and interferon γ) and to the anabolic hormone insulin like growth factor (IGF-1). We show that the IL-1β and interferon type 1 increased atrogin-1 mRNA expression whereas IGF-1 suppressed atrogin-1 expression. The proximal promoter of salmon atrogin-1 was used to transfect primary muscle cell cultures and we found all three cytokines increased promoter activity whereas there was a decrease caused by IGF-1 exposure. We hypothesise that the main drivers for atrogin-1 expression are via the conserved FOXO site, but other transcription binding sites such as NFκB, STAT and IRFs may also be involved in a synergistic manner following immune stimulation when free amino acids need to be released for muscle protein reserves.

Reactive oxygen species mediate axis-cotyledon signaling to induce reserve mobilization during germination and seedling establishment in Vigna radiata

Seeds represent an excellent opportunity to investigate the role of reactive oxygen species (ROS) in control of metabolism during germination and seedling establishment. Cotyledons, the storage organs in Vigna, do not display growth/cell division while the embryonic axis shows rapid growth and intense metabolic activity. The present study investigates the possibility of ROS generated during respiration in the axis serving as messengers guiding storage reserve mobilization from cotyledons at the pre-greening stage. Seeds were germinated in the presence of hydroxyurea to halt cell division in the S-phase and separately in Edaravone, a potent free radical scavenger. Both treatments caused a decrease in germination percentage, seedling growth and protein mobilization. In the growing axis, both treatments resulted in a decrease in hydrogen peroxide (H2O2), total ROS, MDA and protein carbonyls. The picture in cotyledons was quite different, owing to the physiological dissimilarities between the tissues. The status of redox as evident by GSH/GSSG ratios tended toward oxidizing in axis in comparison to the highly reducing environment found in cotyledons. This is construed as a tendency to maintain redox buffering on the oxidizing side in the axis, to facilitate the passage of ROS message. These results strongly indicate that suppression of cell division or scavenging of ROS adversely affects protein reserve mobilization. It is proposed that apart from H2O2 being a transportable signal, the final message perceived in cotyledons also comprises lipid peroxidation, protein carbonylation and alteration of redox status of the glutathione pool.

Hydrogen peroxide might be a downstream signal molecule of hydrogen sulfide in seed germination of mung bean (Vigna radiata)

AbstractHydrogen sulfide (H

Autophagy in the fat body cells of the cave cricket Troglophilus neglectus Krauss, 1878 (Rhaphidophoridae, Saltatoria) during overwintering

The cave cricket Troglophilus neglectus regularly overwinters for 4-5 months in hypogean habitats. Winter dormancy is a natural starvation period, providing the opportunity to study autophagy under natural conditions. We aimed to evaluate the autophagic activity in adipocytes and urocytes of the fat body in three time frames: directly before overwintering, in the middle of dormancy, and at its end. For this purpose, we sampled individuals in caves. The cell ultrastructure was studied by transmission electron microscopy (TEM) and the abundance of autophagosomes by immunofluorescence microscopy (IFM), applying the widely used, specific immunolabeling marker microtubule-associated protein 1 light chain 3 (LC3). Before overwintering, TEM revealed scarce autophagosomes and residual bodies in the adipocytes and none in the urocytes. Congruently, IFM showed a very limited or no reaction. In the middle and at the end of overwintering, in both cell types, phagophores, autophagosomes, autolysosomes, and residual bodies were identified by TEM, while LC3 immunolabeling for detecting autophagosomes showed a conspicuous positive reaction. Both methods revealed that there were no significant differences between the sexes in any time frame. Minimal autophagic activity was detected before the winter dormancy, and it gradually intensified till the end of overwintering, probably because reserve proteins in protein granula are not composed of all the required amino acids. We conclude that in T. neglectus, autophagy is a substantial response to starvation and supports homeostatic processes during winter dormancy by supplying cells with nutrients.

<b>Wheat technological quality as affected by nitrogen fertilization under a no-till system

Wheat is a major cereal crop cultivated worldwide that plays a strategic role in human nutrition. Differently from several other crops, wheat’s technological properties are essential for its commercialization and utilization. Its reserve protein, known as gluten, presents unique rheological properties that can enable the raw material to be used for different industrial uses, mainly for bread making, pasta, cookies and cakes. In the current work, a field trial examined the effects of three urea-based fertilizers and four nitrogen (N) rates on selected physical, physicochemical and rheological characteristics of kernels and flour of wheat grown under a no-till system. The results showed no differences among the three fertilizers but the highest N rates produced changes, decreasing the thousand kernel weight and test weight (PH) and increasing kernel protein content and the gluten content of the flour. Multivariate statistical analysis techniques (principal component analysis and hierarchical cluster analysis) were also effective in differentiating the fertilizers based on the evaluated responses.

국내 수수 종자의 용해도별 단백질 함량 변이

우리나라 수수 유전자원 20품종에 대한 종자 단백질의 정량적 및 정성적 특성을 분석하였다. 수수 종자의 수용성 단백질의 분획은 'Osborne 방법'의 변형된 방법으로서 알부민, 글로불린, 프롤라민 및 글루텔린을 순차적으로 분리하여 정량분석을 실시하였다. 수수 종자의 저장단백질인 프롤라민 단백질의 조성을 1차 전기영동으로 비교 분석하였다. 1. 총 단백질 함량 대비 분획단백질의 함량은 알부민 단백질은 6.2%, 글로불린 단백질은 0.9%, 프롤라민 단백질은 57.9% 및 글루텔린 단백질은 35.1%의 함량을 나타내었다. 2. 품종별 비교에서 프롤라민 단백질의 함량이 높은 품종은 흰수수, 흰찰수수, 황금찰수수 및 대풍수수로 결정되었다. 3. <TEX>${\alpha}$</TEX>-kafirin의 함량이 높은 품종은 흰수수, 금산찰수수, 흰찰수수 및 장목수수로 나타났다. 4. 흰수수와 흰찰수수가 고 프롤라민 및 고 <TEX>${\alpha}$</TEX>-kafirin 품종임을 제시하였다. Sorghum seed is traditionally used as health supplements and the secondary food mixed with rice in Korea. While the research of reserve protein in sorghum seed have been carried out in many countries used as major food, much less is known about reserve proteins of Korean local sorghum seeds. To obtain protein characteristics in 20 Korean local sorghum seed, quantitative content of reserve protein was determined after fractionation by modified 'Osbone' method and <TEX>${\alpha}$</TEX>-kafirin of prolamin was determined by SDS-PAGE. Mean albumin, globulin, prolamin and glutelin contents based on total seed protein content of 20 Korean local sorghum seed were 6.2%, 0.9%, 57.9% and 35.1%, respectively. Sorghum cultivar with high prolamin were 'Whin-susu', 'Whin-Chalsusu', 'Whanggeum-Chalsusu', and 'Daepungshushu'. Sorghum cultivar with high <TEX>${\alpha}$</TEX>-kafirin were 'Whin-susu', 'Geumsan-Chalsusu', 'Whin-Chalsusu', and 'Jangmok-susu'. Among the 20 varieties, 'Whin-susu' and 'Whin-Chalsusu' were selected as high <TEX>${\alpha}$</TEX>-kafirin and prolamin sorghum cultivar, which showed 64.5 and 71.9% of prolamin contents, respectively.

Salt-induced delay in cotyledonary globulin mobilization is abolished by induction of proteases and leaf growth sink strength at late seedling establishment in cashew

Seedling establishment in saline conditions is crucial for plant survival and productivity. This study was performed to elucidate the biochemical and physiological mechanisms involved with the recovery and establishment of cashew seedlings subjected to salinity. The changes in the Na+ levels and K/Na ratios, associated with relative water content, indicated that osmotic effects were more important than salt toxicity in the inhibition of seedling growth and cotyledonary protein mobilization. Salinity (50mM NaCl) induced a strong delay in protein breakdown and amino acid accumulation in cotyledons, and this effect was closely related to azocaseinolytic and protease activities. In parallel, proline and free amino acids accumulated in the leaves whereas the protein content decreased. Assays with specific inhibitors indicated that the most important proteases in cotyledons were of serine, cysteine and aspartic types. Proteomic analysis revealed that most of the cashew reserve proteins are 11S globulin-type and that these proteins were similarly degraded under salinity. In the late establishment phase, the salt-treated seedlings displayed an unexpected recovery in terms of leaf growth and N mobilization from cotyledon to leaves. This recovery coordinately involved a great leaf expansion, decreased amino acid content and increased protein synthesis in leaves. This response occurred in parallel with a prominent induction in the cotyledon proteolytic activity. Altogether, these data suggest that a source–sink mechanism involving leaf growth and protein synthesis may have acted as an important sink for reserve mobilization contributing to the seedling establishment under salinity. The amino acids that accumulated in the leaves may have exerted negative feedback to act as a signal for the induction of protease activity in the cotyledon. Overall, these mechanisms employed by cashew seedlings may be part of an adaptive process for the efficient rescue of cotyledonary proteins, as the cashew species originates from an environment with N-poor soil and high salinity.

Upper arm composition and nutritional status of school children and adolescents in Abeokuta, Southwest Nigeria

Upper arm composition is a reflection of body protein and calorie reserves. However, there is a paucity of data on upper arm composition of children from African countries, including Nigeria. This study aimed to determine the composition of upper arm and nutritional status of school children in Abeokuta, Nigeria and to compare with international reference standards. The sensitivity and specificity of upper arm muscle area by height (UAMAH) as a nutritional assessment tool was also determined. Five hundred and seventy children aged 5 to 19 years were selected from seven schools using multistage random sampling. Weight, height, mid-upper arm circumference (MUAC) and triceps skin fold thickness (TSF) were measured. Body mass index, upper arm muscle area (UAMA), upper arm fat area (UAFA), fat percentage and UAMAH were derived. The TSF, UAFA and fat percentage were significantly higher in females than males at each age group. MUAC and UAMA were significantly higher in female children aged 10-14 years, whereas UAMA was significantly higher in male children aged 15-19 years. UAMA and UAFA of the children were lower than those of Americans but similar to those of Zimbabweans, and higher than those of Indians. The sensitivity and specificity of UAMAH for detecting wasting were 80.8% and 63.9%, respectively, whereas the corresponding values for stunting were 32.2% and 58.2%, respectively. The school children studied have a combination of poor calorie and protein reserve. UAMAH may be a valuable tool for complete evaluation of the nutritional status of school children.

Chronic stress alters concentrations of corticosterone receptors in a tissue-specific manner in wild house sparrows (Passer domesticus).

The physiological stress response results in release of glucocorticoid hormones such as corticosterone (CORT). Whereas short-term activation of this response helps animals cope with environmental stressors, chronic activation can result in negative effects including metabolic dysregulation and reproductive failure. However, there is no consensus hormonal profile of a chronically stressed animal, suggesting that researchers may need to look beyond hormone titers to interpret the impacts of chronic stress. In this study, we brought wild house sparrows (Passer domesticus) into captivity. We then compared glucocorticoid and mineralocorticoid receptor concentrations in sparrows exposed either to a standardized chronic stress protocol (n=26) or to standard husbandry conditions (controls; n=20). We used radioligand binding assays to quantify receptors in whole brain, liver, kidneys, spleen, gonads, gastrocnemius and pectoralis muscle, omental and subcutaneous fat, and bib and back skin. In most tissues, CORT receptors did not differ between controls and stressed animals, although we found marginal increases in receptor density in kidney and testes in stressed birds at some time points. Only in pectoralis muscle was there a robust effect of chronic stress, with both receptor types higher in stressed animals. Increased pectoralis sensitivity to CORT with chronic stress may be part of the underlying mechanism for muscle wasting in animals administered exogenous CORT. Furthermore, the change in pectoralis was not paralleled by gastrocnemius receptors. This difference may help explain previous reports of a greater effect of CORT on pectoralis than on other muscle types, and indicate that birds use this muscle as a protein reserve.

The major egg reserve protein from the invasive apple snail Pomacea maculata is a complex carotenoprotein related to those of Pomacea canaliculata and Pomacea scalaris

Snails from the genus Pomacea lay conspicuous masses of brightly colored eggs above the water. Coloration is given by carotenoproteins that also which play important roles in protection against sun radiation, stabilizing and transporting antioxidant molecules and helping to protect embryos from desiccation and predators. They seem a key acquisition, but have been little studied. Here we report the characteristics of the major carotenoprotein from Pomacea maculata and the first comparison among these egg proteins. This particle, hereafter PmPV1, represents ~52% of perivitellin fluid protein. It is a glyco-lipo-carotenoprotein responsible for the bright reddish egg coloration. With VHDL characteristics, PmPV1 apparent molecular mass is 294kDa, composed of five non-covalently bound subunits of pI 4.7-9.8 and masses between 26 and 36kDa whose N-terminal sequences were obtained. It is a glyco-lipo-carotenoprotein scarcely lipidated (<1%) but highly glycosilated (13% by wt). Lipids include phospholipids, free fatty acids and carotenoids; mannose and galactose predominate over other monosaccharides. Main carotenoids are esterified and non-esterified astaxanthin (71 and 25%, respectively). Carotenoid removal does not seem to affect the structural characteristics of the oligomer, while deglycosilation reduces subunit number from five to a single one. The carotenoid-protein association protected the former against oxidation. PmPV1 cross reacts with polyclonal antibodies against the PcOvo, the major carotenoprotein from Pomacea canaliculata. The characterization of PmPV1 allows the first comparisons among snail carotenoproteins and further highlights the importance of these perivitellins in the reproductive strategy of Pomacea.

Differential RNA- and protein-expression profiles of cactus seeds capable of hydration memory

AbstractHydration memory is a phenomenon in which a seed can tolerate discontinuous hydration periods, displaying enhanced germination after one or multiple hydration–dehydration (HD) cycles; it was described physiologically in a few cactus species around 15 years ago. Although no additional work was done on this subject, it has great biotechnological potential since its analysis would permit predictions about whether a seed can withstand discontinuous hydration; in the long run, the knowledge about its regulation might lead to induction of this resistance, so we aimed to provide an initial approach to the molecular mechanisms that underlie hydration memory. This phenomenon was reproduced successfully in our lab with Ferocactus peninsulae seeds. Using two-dimensional (2D) electrophoresis, we compared expression patterns of proteins involved in seed maturation of seeds and seedlings subjected to an HD cycle treatment. We found differential expression of several proteins possibly involved in primary metabolism, ubiquitination pathway and reserve protein availability regulation in seeds and seedlings subjected to an HD cycle. We also found differential stability of total RNA. These results strongly suggest that the differential expression of proteins is at least partially related to the hydration memory process.

Polymorphism of Hordein Reserve Proteins of Barley Genotypes

Polymorphism of Hordein Reserve Proteins of Barley Genotypes

Proteome Analysis of Plastids from Developing Seeds of Jatropha curcas L.

In this study, we performed a proteomic analysis of plastids isolated from the endosperm of developing Jatropha curcas seeds that were in the initial stage of deposition of protein and lipid reserves. Proteins extracted from the plastids were digested with trypsin, and the peptides were applied to an EASY-nano LC system coupled inline to an ESI-LTQ-Orbitrap Velos mass spectrometer, and this led to the identification of 1103 proteins representing 804 protein groups, of which 923 proteins were considered as true identifications, and this considerably expands the repertoire of J. curcas proteins identified so far. Of the identified proteins, only five are encoded in the plastid genome, and none of them are involved in photosynthesis, evidentiating the nonphotosynthetic nature of the isolated plastids. Homologues for 824 out of 923 identified proteins were present in PPDB, SUBA, or PlProt databases while homologues for 13 proteins were not found in any of the three plastid proteins databases but were marked as plastidial by at least one of the three prediction programs used. Functional classification showed that proteins belonging to amino acids metabolism comprise the main functional class, followed by carbohydrate, energy, and lipid metabolisms. The small and large subunits of Rubisco were identified, and their presence in the plastids is considered to be an adaptive feature counterbalancing for the loss of one-third of the carbon as CO2 as a result of the conversion of carbohydrate to oil through glycolysis. While several enzymes involved in the biosynthesis of several precursors of diterpenoids were identified, we were unable to identify any terpene synthase/cyclase, which suggests that the plastids isolated from the endosperm of developing seeds do not synthesize phorbol esters. In conclusion, our study provides insights into the major biosynthetic pathways and certain unique features of the plastids from the endosperm of developing seeds at the whole proteome level.

Immune response of twin-bearing Merino ewes when infected with Haemonchus contortus: Effects of fat score and prepartum supplementation

The benefit of providing prepartum protein supplementation to twin-bearing Merino ewes with low and high fat score (FS; measure of soft tissue depth related to fatness) was investigated to quantify effects on host resilience and immunity to Haemonchus contortus. The experiment was conducted on low quality pastures from day (d) -91 to weaning at d 52, relative to the mid-point of lambing (d 0). The experimental design consisted of two feeding regimes designed to achieve FS targets of 2 (low) and 4 (high) by d -47 followed by allocation to protein supplementation groups (0 or 200g/d cottonseed meal; CSM) until d 10. Throughout the experiment there were two infection groups (0 or 750 H. contortus third stage larvae (L3)/week). Peri and postparturient ewes were susceptible to H. contortus shown as a rise in worm egg count (WEC). High FS group ewes had a significant benefit in terms of protection against H. contortus, but this was restricted to the prepartum period. There were no benefits of supplemental protein which did not enhance protective immunity. Lower prepartum WEC from high FS ewes was associated with higher levels of circulating eosinophils but a general decline in counts occurred prior to parturition. Infected ewes had elevated antibody titres and a greater number of mast cells in abomasal tissue at slaughter on d 52. The results suggest that sufficient fat and protein reserves are important for twin-bearing Merino ewes during pregnancy to elevate the immune response against H. contortus whereas strategic prepartum protein supplementation had no benefit.

Metabolic Rate and Prehibernation Fattening in Free-Living Arctic Ground Squirrels

Hibernating mammals become sequestered and cease foraging during prolonged seasonal periods of reduced or unpredictable food availability and instead rely on cached food and/or endogenous reserves of fat and protein accumulated during the previous active season. The gain in weight is due to increased food consumption, but it also has been hypothesized that hibernators maximize rates of fattening by decreasing costs of maintenance before weight gain, reflected in reduced resting metabolic rate (RMR). We recorded repeated measures of total body, lean, and fat mass in individual adult male and female arctic ground squirrels across their active season and found that squirrels increased body mass by 42% (males) and 62% (females). This gain was achieved through a 17% increase in lean mass and a 7-8-fold increase in fat mass; however, mass gain was not linear and patterns differed between sexes. Contrary to our hypothesis, decreases in RMR were not associated with rapid mass gain. We found RMR of males increased (whole-animal RMR or lean-mass-specific RMR) or remained constant (mass-specific RMR) for most of the active season and decreased only after the majority of mass had been gained. In females, although RMR (whole-animal, mass-specific, and lean-mass RMR) generally decreased across the active season, the greatest decrease occurred late in the active season after the majority of mass had been gained. In conclusion, arctic ground squirrels do not trade off metabolism to facilitate rates of weight gain before hibernation, but they do use energy sparing strategies before hibernation that help maintain peak mass.

Seed structure, germination, and reserve mobilization in Butia capitata (Arecaceae)

Butia capitata is a palm tree endemic to the Cerrado biome of Brazil and has significant potential for ornamental and food uses. In this work, we characterized the structures of the seeds and seedlings of this species to identify anatomical aspects related to its pronounced dormancy and determine the processes involved in reserve mobilization. Intact seeds, and seeds from which the operculum had been removed, were allowed to germinate and their morphology, physiology, anatomy, and histochemistry, together with those of the seedlings, were followed for 30 days. The seed coat was found to be rich in phenolic compounds and not lignified. The endosperm contains abundant protein and lipidic reserves, and the embryo has additional starch reserves. Germination occurred only in seeds with their opercula removed and involved the elongation of the cotyledon cells and meristematic activity in the “M zone” located between the embryonic axis and the proximal extremity of the embryo. The mobilization of embryonic reserves initiates during the first phase of imbibition, while the mobilization of endosperm reserves represents a post-germination event associated with the formation of a secretory epidermis and aerenchyma and the vascularization of the haustorium. Seeds with intact opercula did not germinate, but demonstrated embryonic reserve mobilization and cell elongation, indicating that dormancy in B. capitata is related to the incapacity of the embryo to dislocate the operculum.

Electrophoretic analysis of malting degradability of major sorghum reserve proteins

Proteolysis is vital to the generation of amino acids and short peptides during malting. The qualitative and quantitative effects of malting on proteolytic digestion were investigated for 11 Botswana sorghum cultivars. Protein hydrolysis was influenced by sorghum grain cultivar. All protein fractions were degraded, although the extents of their digestion appeared cultivar-dependent. The most significant changes in total and free kafirins occurred among the HMW aggregates while the 45 kDa dimer appeared the most recalcitrant. Free kafirin monomers were digested in variety-defined manner; α-kafirin faded the most (ca. 82%) in Phofu, but appeared least digested (≤10%) in Lekgeberwa; β-kafirin faded the most in Phofu and Segaolane (90–94%) but only 46% in Lekgeberwa. Overall, α-kafirin appeared the least digested of the free monomers. The proportion of free kafirin accounted for by the 45 kDa and monomeric kafirins increased in all malts (except Lars Vyt and Mafia), probably due to protein depolymerisation. Grain variety significantly influenced (p < 0.001) malt FAN levels. Mean FAN values were highest in Segaolane (225 mg/100 g) followed by Sefofu, Town and BSH-1, but lowest in Mafia (96.9 mg/100 g). Results indicate wide variability in the proteolytic malting digestibility of the eleven sorghum cultivars.