Some factors affecting the respiration of some aquatic plants

Summary The oxygen consumption of four aquatic plants has been determined at various concentrations of dissolved oxygen and at three different temperatures.Oxygen consumption rates (mg oxygen/g dry weight per hr) at 20°C in air-saturated water were Berula erecta, 1.25; Callitriche obtusangula, 2.8; Hippuris vulgaris, 1.96; and Ranunculus pseudofluitans, 1.90.Oxygen consumption rates increased with increase in dissolved-oxygen concentration within the experimental limits of 1.2–17 p.p.m. dissolved oxygen. The relation of oxygen consumption to this range of oxygen concentrations can be described by the empirical equation R = aC ^b. Increase of temperature has been shown to increase the rates of oxygen consumption. Q₁₀ values ranging from 1.32 to 3.48 have been obtained.     

Dynamics of energy metabolism in ontogenesis of striped shield bug (<Emphasis Type="Italic">Graphosoma lineatum</Emphasis> L.) and cabbage moth (<Emphasis Type="Italic">Mamestra brassicae</Emphasis> L.)

Dynamics of growth and oxygen consumption during ontogenesis of insects with direct (striped shield bug Graphosoma lineatum L.) and indirect (cabbage moth Mamestra brassicae L.) development have been compared. The correlation between a character of energy metabolism alteration and peculiarities of development of the insects has been shown. Cyclic decrease of oxygen consumption during molt and sharp dropping during metamorphosis have been observed in insects with indirect development. The decrease of oxygen consumption has been observed in insects with direct development only during molts. The coefficient a of allometric dependence of oxygen consumption on body weight of imago for cabbage moth was two times higher than that for striped shield bug.     

Standard Metabolic Rate in Gastropoda Class

Abstarct—The relationship between oxygen consumption and soft tissue weight in the Gastropoda class (according to the obtained and published data) is expressed by the equation with coefficientsa = 0.71 and k = 0.78. Prosobranch and pulmonate snails have similar levels of oxygen consumption. Opisthobranch snails have higher oxygen consumption. No relationship has been revealed between the metabolic rate (coefficient a) and climatic zone of the gastropod habitat.     

Correlation between glucose/fructose discrepancy and hexokinase kinetic properties in different <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> wine yeast strains

Grape juice contains about equal amounts of glucose and fructose, but wine strains of Saccharomyces cerevisiae ferment glucose slightly faster than fructose, leading to fructose concentrations that exceed glucose concentrations in the fermenting must. A high fructose/glucose ratio may contribute to sluggish and stuck fermentations, a major problem in the global wine industry. We evaluated wine yeast strains with different glucose and fructose consumption rates to show that a lower glucose preference correlates with a higher fructose/glucose phosphorylation ratio in cell extracts and a lower K _m for both sugars. Hxk1 has a threefold higher V _max with fructose than with glucose, whereas Hxk2 has only a slightly higher V _max with glucose than with fructose. Overexpression of HXK1 in a laboratory strain of S. cerevisiae (W303–1A) accelerated fructose consumption more than glucose consumption, but overexpression in a wine yeast strain (VIN13) reduced fructose consumption less than glucose consumption. Results with laboratory strains expressing a single kinase showed that total hexokinase activity is inversely correlated with the glucose/fructose (G/F) discrepancy. The latter has been defined as the difference between the rate of glucose and fructose fermentation. We conclude that the G/F discrepancy in wine yeast strains correlates with the kinetic properties of hexokinase-mediated sugar phosphorylation. A higher fructose/glucose phosphorylation ratio and a lower K _m might serve as markers in selection and breeding of wine yeast strains with a lower tendency for sluggish fructose fermentation.     

Carcass feeding as a cryptic foraging mode in round goby Neogobius melanostomus

Round gobies Neogobius melanostomus were observed readily consuming soft tissue from carcasses of larger fishes under both laboratory and field conditions. Consumption normally progressed in a typical sequence, starting with soft and easily accessible tissues such as the eyes, followed by puncture of the abdominal cavity, gut consumption and then muscle consumption. Carcass feeding has not previously been seen in N. melanostomus and has potential consequences for transfer of nutrients and contaminants.     

Are rodents a source of biotic resistance to tree invasion in Pampean grasslands? Tree seed consumption under different conditions

Biotic resistance has been invoked as a major barrier to woody species invasion, although the role of resident generalist consumers and their interaction with seed availability in a local community has received little attention. We assessed tree seed consumption by rodents under two different scenarios: (i) We documented in field spatio‐temporal patterns of seed predation by native rodents on two exotic tree species, Gleditsia triacanthos or ‘honey locust’ and Robinia pseudoacacia or ‘white locust’ (family Leguminosae), in five grassland habitats of the Inland Pampa, Argentina. (ii) We conducted laboratory feeding trials to evaluate tree seed consumption in the presence (cafeteria‐style feeding trials) and in the absence (non‐choice feeding trials) of alternative food supplies. Seed predation was generally higher for Robinia than for Gleditsia seeds, both in field and laboratory conditions. For both tree species, seed predation varied between habitats and seasons and was higher in the native tussock grassland than in the remaining studied communities, whereas the crop field showed the lowest levels of consumption along with the absence of captured rodents. Seed consumption of Gleditsia and Robinia among the four grassland communities (which did not differ in rodent abundance) was negatively associated with the availability of alternative food. Laboratory feeding trials showed a higher consumption of Gleditsia seeds in the non‐choice than in the cafeteria‐style feeding trials, while the consumption of Robinia seeds did not differ in the absence or presence of alternative seeds. These patterns indicate that the contribution of resident granivores to invasion resistance might depend on colonizer species identity, recipient community type and season of the year. We suggest that rodent preferences for different invader seeds will interact with the availability of alternative food in the local habitat in influencing the amount of predator‐mediated biotic resistance to invasion.     

The effect of activity on oxygen consumption,oxygen debt,and heart rate in the lizardsVaranus gouldii andsauromalus hispidus

Summary Oxygen consumption and heart rate were measured during rest and activity in the lizardsVaranus gouldii andSauromalus hispidus. Oxygen debt was calculated from postactive oxygen consumption. Standard metabolic rates of the two animals are similar butVaranus consumes much more oxygen during activity than doesSauromalus (Fig. 1–3). The latter has a constant active metabolic rate above 30 ° C and accumulates a large oxygen debt, which is repayed slowly (Fig. 4).Varanus recovers rapidly from activity (Fig. 5), presumably because of the smaller lactacid debt incurred. Heart rate increment inSauromalus is high (Fig. 8). This variable cannot be responsible for the limitation of active oxygen consumption; calculations of oxygen pulse suggest that an inability to increase A-V difference and/or stroke volume are implicated (Fig. 9).Varanus have evolved mechanisms to sustain high levels of oxygen consumption superior to those of other reptiles investigated. The role of anaerobiosis in the biology of both animals is discussed.     

Energy consumption by embryos of a viviparous lizard, Eulamprus tympanum, during development

Energy consumption during development has been measured in many oviparous lizards, but not in viviparous lizards in utero. It has always been assumed that energy consumption by embryos of viviparous lizards during development is similar to that of oviparous species. Estimation of energy consumption of viviparous lizards in vivo are confounded by the possible influence of pregnancy on maternal metabolism. Here we separated maternal and embryonic metabolism in measurements of pregnant Eulamprus tympanum throughout pregnancy. Our data support the hypothesis that the energetic cost of development in viviparous lizards (19.8 kJ g⁻¹) is similar to that in oviparous lizards (mean 16.2 kJ g⁻¹), at least for a species with a simple placenta. An increase in maternal metabolism of 29% above that for non-pregnant E. tympanum goes to maintain pregnancy, and represents an important component of the reproductive effort in E. tympanum.     

A versatile and scalable strategy for glycoprofiling bifidobacterial consumption of human milk oligosaccharides

Human milk contains approximately 200 complex oligosaccharides believed to stimulate the growth and establishment of a protective microbiota in the infant gut. The lack of scalable analytical techniques has hindered the measurement of bacterial metabolism of these and other complex prebiotic oligosaccharides. An in vitro, multi‐strain, assay capable of measuring kinetics of bacterial growth and detailed oligosaccharide consumption analysis by FTICR‐MS was developed and tested simultaneously on 12 bifidobacterial strains. For quantitative consumption, deuterated and reduced human milk oligosaccharide (HMO) standards were used. A custom software suite developed in house called Glycolyzer was used to process the large amounts of oligosaccharide mass spectra automatically with ¹³C corrections based on de‐isotoping protocols. High growth on HMOs was characteristic of Bifidobacterium longum biovar infantis strains, which consumed nearly all available substrates, while other bifidobacterial strains tested, B. longum bv. longum, B. adolescentis, B. breve and B. bifidum, showed low or only moderate growth ability. Total oligosaccharide consumption ranged from a high of 87% for B. infantis JCM 7009 to only 12% for B. adolescentis ATCC 15703. A detailed analysis of consumption glycoprofiles indicated strain‐specific capabilities towards differential metabolism of milk oligosaccharides. This method overcomes previous limitations in the quantitative, multi‐strain analysis of bacterial metabolism of HMOs and represents a novel approach towards understanding bacterial consumption of complex prebiotic oligosaccharides.     

Meat eating in wild hamadryas baboons: Opportunistic trade‐offs between insects and vertebrates

The consumption of meat may provide herbivorous animals with important nutrients that are scarce in their plant‐based diet. Seasonal variation in plant food availability has been suggested to motivate dietary flexibility in a range of species and thus primates may seek more prey when key plant resources are unavailable. Alternatively, prey encounter rate may drive meat eating. Here we investigate patterns of meat eating in hamadryas baboons (Papio hamadryas) at Filoha, Awash National Park, Ethiopia. The Filoha baboons rely largely on doum palm fruit (Hyphaene thebaica), which are available most months of the year, and the young leaves of Acacia senegal, which are more abundant during the wet season. We hypothesized that the baboons would consume more meat when H. thebaica and A. senegal were less available, which we tested by comparing meat eating and consumption of these plant food species from March 2005 through February 2006. Our results reveal a high rate of vertebrate meat eating at Filoha (0.028/hour of observation) compared with other hamadryas sites. We found no relationship, however, between meat eating (either insect or vertebrate) and either rainfall or consumption of H. thebaica or A. senegal, indicating that availability of preferred plant resources does not drive meat consumption. Vertebrate consumption and time spent feeding were significantly negatively associated; there was no relationship, however, between the consumption of animal matter and either home range size or daily path length. Vertebrate and insect consumption alternated throughout the year such that the baboons maintained a small amount of animal matter in their diet year‐round. Our results suggest that the baboons do not often actively seek animal matter, but consume it opportunistically, with the presence of locust and dragonfly swarms driving insect consumption, and both prey availability and the availability of feeding time shaping vertebrate predation.     

Temperaturadaptation und Sauerstoffverbrauch bei Eidechsen

Zusammenfassung 1. Verschiedene Arten der GattungLacerta haben bei einer gleichbleibenden gemäßigten und hohen Temperatur eine verschiedene Stoffwechselintensität. Bei niedrigen Temperaturen verschwinden diese Unterschiede.2. Der Prozeß der thermischen Adaptation an die neue Temperatur geht auf zwei Weisen vor sich. Bei einzelnen Arten (Lacerta melisellensis undL. oxycephala) verläuft der Adaptationsprozeß von Anfang an ständig in der Richtung des Erreichens jener Werte des Stoffwechsels, welche das ruhende Tier bei der früheren Adaptationstemperatur hatte. BeiLacerta sicula dagegen fällt die Intensität des Stoffwechsels in den ersten Tagen des Aufenthaltes bei niederen Temperaturen, um später anzusteigen und sich jenem Wert zu nähern, den die Tiere bei ihren früheren Adaptationstemperaturen hatte.3. Die EidechsenLacerta melisellensis undL. oxycephala zeigen bei jeder Adaptationstemperatur nach Beendigung des Adaptationsprozesses die gleiche Intensität des Sauerstoffverbrauches. BeiLacerta muralis ist der Sauerstoffverbrauch bei einer höheren Adaptationstemperatur höher als bei einer niedrigeren.4. Bei Adaptation an eine neue, annähernd gleichbleibende Außentemperatur bleibt die Körpertemperatur praktisch unverändert. Auf diese Weise wird der Stoffwechsel des ruhenden Tieres in gewisser Hinsicht von der Höhe der Körpertemperatur während des Adaptationsprozesses unabhängig.

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Temperature adaptation and oxygen consumption in lizards

In some lizards the process of thermal adaptation and oxygen consumption at adaptation temperatures has been examined after completion of adaptation. A slow decrease of oxygen consumption was found for a certain period inLacerta sicula after transfer from a warm into a cold surrounding. The values of oxygen consumption increased from the ninth day and reached values corresponding to the new external temperature after about 3 weeks. InL. melisellensis andL. oxycephala adaptation to a new lower temperature occurs with the beginning of the increasing oxygen consumption, the adaptation lasting about 3 weeks. InL. muralis oxygen consumption at low adaptation temperature is lower after the process of adaptation than at higher adaptation temperature. In contrast, oxygen consumption ofL. melisellensis andL. oxycephala after adaptation to lower external temperatures is equal to the oxygen consumption at higher external temperatures, so that the animal shows the same intensity of oxygen consumption in spite of its different body temperature.

     

Walnut Consumption Increases Satiation but Has No Effect on Insulin Resistance or the Metabolic Profile Over a 4‐day Period

Obesity and diabetes have been associated with increased consumption of highly processed foods, and reduced consumption of whole grains and nuts. It has been proposed, mainly on the basis of observational studies, that nuts may provide superior satiation, may lead to reduced calorie consumption, and may decrease the risk of type 2 diabetes; but evidence from randomized, interventional studies is lacking. A total of 20 men and women with the metabolic syndrome participated in a randomized, double‐blind, crossover study of walnut consumption. Subjects had two 4‐day admissions to the clinical research center where they were fed an isocaloric diet. In addition, they consumed shakes for breakfast containing either walnuts or placebo (shakes were standardized for calories, carbohydrate, and fat content). Appetite, insulin resistance, and metabolic parameters were measured. We found an increased level of satiety (overall P value = 0.0079) and sense of fullness (P = 0.05) in prelunch questionnaires following the walnut breakfast as compared to the placebo breakfast, with the walnut effect achieving significance on day 3 and 4 (P = 0.02 and P = 0.03). We did not find any change in resting energy expenditure, hormones known to mediate satiety, or insulin resistance when comparing the walnut vs. placebo diet. Walnut consumption over 4 days increased satiety by day 3. Long‐term studies are needed to confirm the physiologic role of walnuts, the duration of time needed for these effects to occur, and to elucidate the underlying mechanisms.     

Rate of consumption of Western flower thrips pupae by the soil-dwelling mite Hypoaspis sclerotarsa (Acari: Laelapidae)

Western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), are one of the most serious pests of horticultural crops worldwide. Despite one third of its lifecycle being in the soil, the potential for biological control of WFT in the soil is poorly understood and requires further elucidation. A number of studies report that polyphagous predatory mites prey on pupal stages of WFT in the soil, but little has been done on consumption rates. Therefore, we designed a laboratory study to examine the rate of consumption of WFT pupae in potting media, by the soil-dwelling mite Hypoaspis sclerotarsa (Costa). Five predator densities were evaluated (0, 2, 4, 6 and 8) against four densities of WFT prey (5, 10, 15 and 20 pupae). Pupal consumption was assessed at 2 hourly intervals over a six-hour period. The study confirmed that H. sclerotarsa did consume WFT pupae and that the rate of consumption increased with increasing density of H. sclerotarsa. The rate of consumption also increased with the density of WFT pupae. However, this was not consistent because, as the numbers of WFT pupae increased, so did the ratio of WFT pupae remaining to those consumed, increase. This paper is the first report of H. sclerotarsa in Kenya, and of its potential as a biocontrol agent of WFT. Further studies are now needed to understand interaction of foliar and soil dwelling predatory mites (H. sclerotarsa) for control of WFT under field conditions.     

Water and Food Consumption Patterns of U.S. Adults from 1999 to 2001

Objective: High water consumption has been proposed as an aid to weight control and as a means of reducing the energy density of the diet. This study examines the relationship between water consumption and other drinking and eating patterns. Research Methods and Procedures: The National Health and Nutrition Examination Survey 1999 to 2001, with responses from 4755 individuals ≥18 years of age, provides the data for this cross‐sectional analysis. A cluster analysis was performed using z‐scores of specific food and beverage consumption to examine patterns. A multinomial logit analysis was used to examine sociodemographic characteristics of each dietary pattern and to examine the effects of water consumption on the likelihood of consuming a non–dairy caloric beverage. All results were weighted to be nationally representative and controlled for design effects. Results: Within the sample, 87% consumed water, with an average daily consumption of 51.9 oz (1.53 liters) per consumer. Water consumers drank fewer soft/fruit drinks and consumed 194 fewer calories per day. Water consumers (potentially a self‐selected sample) consumed more fruits, vegetables, and low‐ and medium‐fat dairy products. Four distinct unhealthy dietary patterns were found that included little or no water consumption. Older and more educated persons used healthier food patterns. Mexican dietary patterns were much healthier than dietary patterns of blacks. Discussion: Water consumption potentially is a dietary component to be promoted, but much more must be understood about its role in a healthy diet. Because high water consumption is linked with healthier eating patterns—patterns more likely to be followed by higher‐educated, older adults—the target of water promotion and healthy diet options should focus on younger and less educated adults.     

Effects of temperature on oxygen consumption and heart rate in the semi‐terrestrial crab,Ocypode sa ratan (Forskål)

The effect of temperature on the rate of oxygen consumption and heart rate has been investigated in the Red Sea, semi‐terrestrial crab, Ocypode saratan. The Q₁₀ values for both oxygen consumption and heart rate were often <2 and were relatively constant over a wide range of temperature. This suggests that O. saratan is well adapted for life in a high temperature environment. It was noted, however, that behavioural mechanisms were important in reducing the degree of temperature stress that could be experienced in the field. The rates of oxygen consumption of immersed crabs were significantly lower than those of crabs maintained in air at the same temperature.     

Consumption rates and food preferences of slugs in a calcareous grassland under current and future CO<Subscript>2</Subscript> conditions

This study explored consumption of a generalist herbivore feeding on leaf tissue of various plant species of a calcareous grassland, and tested whether consumption levels and preferences changed when plants were exposed to 5 years of in situ CO₂ enrichment. The first part of this experiment tested whether the consumption patterns of slugs (Deroceras reticulatum) observed in single-species feeding tests were altered when slugs were given a choice of food sources. Overall consumption increased 270% when slugs were given a choice, and they preferred having a choice of food sources more than they preferred having any one food source. Surprisingly, slugs consumed fewer legumes and grasses and more non-leguminous forbs when given a choice. In the second part of this experiment, feeding behaviors of slugs in response to elevated CO₂ were investigated by feeding them leaves of two legumes, one grass, and a non-leguminous forb (Trifolium medium, Lotus corniculatus, Bromus erectus, and Sanguisorba minor, respectively) in two or four species combinations. In the leguminous species mix, the non-leguminous species mix, and the combined mix (legumes and non-legumes), neither overall consumption by herbivores nor species preference was significantly altered by long-term CO₂ enrichment. In the combined species mix, slugs preferred legumes to non-legumes (P=0.012) and exhibited a weak functional group preference shift from non-legumes to legumes (P=0.089) in response to CO₂ enrichment. This is the first time such a shift has been observed, and provides evidence that there may be multiple herbivore responses to rising atmospheric CO₂ concentrations. Numerous single-species feeding tests using insects have shown that consumption by herbivores may increase when herbivores are fed plants grown in enriched CO₂ atmospheres. This study clearly demonstrates the limited applicability of non-choice feeding trials to generalist herbivores in species-rich communities. Received: 19 August 1999 / Accepted: 20 April 2000     

P-NMR saturation transfer measurements of phosphate consumption in Saccharomyces cerevisiae

³¹P-NMR measurements of saturation transfer have been used to measure phosphate consumption in respiratory competent cells of the yeast Saccharomyces cerevisiae. Measurements of oxygen consumption and maintenance of the cells in a metabolic steady state during the NMR experiments were facilitated by immobilisation of the cells in an agarose gel matrix which could be perfused in the NMR spectrometer. The contribution of glycolysis to the observed rate of phosphate consumption was estimated by simultaneously measuring glucose consumption and ethanol production in the perfusion buffer. The remaining phosphate consumption, which was attributed to flux through the reaction catalysed by the mitochondrial ATP synthase, combined with measurements of oxygen consumption allowed estimation of a P:O ratio (mol ATP synthesised:atoms oxygen consumed) which was close to 3.     

Rice bran supplement prevents UVB-induced skin photoaging in vivo

Although rice bran consumption is reportedly has numerous beneficial effects on human health, the relationship between rice bran and the prevention of photoaging has not been investigated in detail. We sought to investigate whether consumption of rice bran supplement (RBS) can elicit preventive effects against UVB-induced photoaging in vivo. Dorsal skin sections of hairless mice were exposed to UVB over 16 weeks. RBS consumption suppressed UVB-induced wrinkle formation and inhibited the loss of water content and epidermal thickening in the mouse skin. Western blot and immunohistochemical analyses revealed that repeated exposure to UVB upregulated matrix metalloproteinase-13 (MMP-13) and cyclooxygenase-2 (COX-2) expression, while consumption of RBS suppressed MMP-13 and COX-2 expression, as well as mitogen-activated protein kinase (MAPK) signaling pathways. These findings suggest that RBS could be a potential bioactive ingredient in nutricosmetics to inhibit wrinkle formation and water content loss via the suppression of COX-2 and MMP-13 expression.     

Do Staurozoa bloom? A review of stauromedusan population biology

We used a comprehensive dataset on the diet of Squalus acanthias in the southwestern Atlantic Ocean (35–55°S) to test the hypothesis that fishery has caused a decrease in the trophic level of this species (fishing down process). Of 3,644 stomachs examined between the years 1985 and 2010, 2,214 (60.77%) contained prey items. Generalized linear models were used to evaluate the support in our data for five explanatory variables (sex, predator’s total length, season, region and decade) that may explain the consumption of the given prey. The frequency of fish, mainly Merluccius hubbsi, and benthos in the stomachs decreased through time, whereas the squid Illex argentinus and jellyfishes exhibited positive trends. The trophic level of S. acanthias declined from the 1980s to the 1990s due to the high consumption of prey items at lower trophic levels. On the other hand, the consumption of argentine anchovy, Engraulis anchoita, an underexploited species, did not reveal changes through time.