Do Strigolactones Regulate Bud Winter Dormancy and Charactrisitc Secondary Metabolism in Tea?

Tea (Camellia sinensis [L.] O. Kuntze.) is an important cash crop, which mainly uses tender shoots and young leaves for manufacturing. Due to the marketing characteristic that earlier made tea has higher price, the time of the breaking of winter dormancy buds in spring is extremely important in tea industry. Strigolactones are a group of carotenoids-derived metabolites which regulates bud outgrowth, shoot branching, tiller angle and environmental stress responses. The role of strigolactones in tea plant was briefly summarized in the current review, with an emphasis of the association of strigolactones on bud ecodormancy and shoot branching. The involvement of strigolactones on the biosynthesis of the tea characteristic metabolites flavonoids, caffeine and theanine were also discussed. Moreover, recent advances on the biosynthesis of strigolactones and its regulation by microRNAs and environmental stresses were also presented. This review provides a basis for future investigations underlying the mechanisms of strigolactones on bud winter dormancy and tea secondary metabolism.     

Package Unit Size and Amount of Food: Do Both Influence Intake?

Objective: Large portions increase intake and are hypothesized to contribute to the obesity epidemic. However, it is unclear if portion size affects intake through changes in the unit size of available food or the overall amount of food available for consumption. Thus, this study examined the independent effects of package unit size and amount of food on intake. It was hypothesized that both variables would influence intake. Research Methods and Procedures: Non‐obese (BMI <30 kg/m²), non‐smoking, unrestrained, college‐aged men (n = 12) and women (n = 16) who regularly consumed (≥3 times/wk) snack foods were randomly assigned to one of four groups crossing package unit size (small vs. large) and amount of food (small vs. large). Participants were given a box with 4 snack foods (potato chips, cheese crackers, cookies, and candy) packaged according to their assigned group to take home and eat over 3 days. Dependent variables were energy and gram intake of provided snack foods. Results: An effect of amount of food was found (p < 0.01). A 100% increase in the amount of food provided produced an 81% increase in energy consumed from the snack foods [small amount, 21,037.6 ± 10,852 kJ (5028 ± 2596 kcal) vs. large amount, 11,640.7 ± 4914.1 kJ (2782 ± 1174 kcal)]. No effect of package unit size was found. Discussion: These results suggest that the amount of food available to eat strongly influences intake.     

Do Social Networks Influence Small-Scale Fishermen’s Enforcement of Sea Tenure?

Resource systems with enforced rules and strong monitoring systems typically have more predictable resource abundance, which can confer economic and social benefits to local communities. Co-management regimes demonstrate better social and ecological outcomes, but require an active role by community members in management activities, such as monitoring and enforcement. Previous work has emphasized understanding what makes fishermen comply with rules. This research takes a different approach to understand what influences an individual to enforce rules, particularly sea tenure. We conducted interviews and used multiple regression and Akaike’s Information Criteria model selection to evaluate the effect of social networks, food security, recent catch success, fisherman’s age and personal gear investment on individual’s enforcement of sea tenure. We found that fishermen’s enforcement of sea tenure declined between the two time periods measured and that social networks, age, food security, and changes in gear investment explained enforcement behavior across three different communities on Nicaragua’s Atlantic Coast, an area undergoing rapid globalization.     

Starch Mobilization in Ultradried Seed of Maize （Zea mays L.） During Germination

The effects of ultradry storage on the starch mobilization in maize (Zea mays L.) seed after aging were investigated. The results indicated that there were no significant differences in the content of ATP, starch, and soluble sugar, as well as the activity of amylase, between ultradried seeds and seeds stored at -20℃ during germination. These results were consistent with the higher level of vigor of the ultradried seed. Sieve tube introduction of a fluorescence dye (carboxyl fluoresceindiacetate) and laser confocal microscopy were used to study the development of plasmodesmata in the ultradried seeds. The results indicated that plasmodesmata developed well in ultradried seeds. Fluorescence analysis also showed that the fluorescence intensity in the radicle of ultradried seeds was stronger than that in seeds with a higher moisture content. This suggests that ultradry treatment has no adverse effects on the seeds. After seed imbibition, cell orgaelles could be resumed. It is concluded that ultradry seed storage is beneficial for maintaining seed vigor and that starchy mobilization proceeds regularly during germination.     

Cell Cycle Activity and β-Tubulin Accumulation During Dormancy Breaking of Acer platanoides L. seeds

Cell cycle events in embryo axes of Norway maple (Acer platanoides L.) seeds were studied during dormancy breaking by flow cytometric analyses of the nuclear DNA content and by immunodetection of β-tubulin. Most embryonic nuclei of dry, fully matured seeds were arrested in the G₂ phase of the cell cycle. In addition, the lowest content of β-tubulin was detected in dry, mature seeds. Imbibition in water and cold stratification resulted in a decrease in the number of nuclei in G₂, and a simultaneous increase in β-tubulin content. In germinated seeds the content of β-tubulin was the highest and the number of cells in G₂ was the lowest. Both cell cycle events preceded cell expansion and division and subsequent growth of the radicle through the seed coat. The anatomical investigation has proved that the main reason for decrease in the number of nuclei in G₂ is mitosis, started with seeds germination (radicle protrusion). The activation of the cell cycle and the β-tubulin accumulation were associated with embryo dormancy breaking. This revised version was published online in July 2006 with corrections to the Cover Date.     

Do flowers wave to attract pollinators? A case study with Silene maritima

To answer the question whether flowers wave to attract pollinators, we determine: (1) the heritability of floral mobility; (2) whether wavy flowers attract more insects; (3) does the duration of pollination affect seed set; and (4) the relationship between seed set and floral mobility. The pollination ecology of Silene maritima was investigated. Flowers on stalks of different waviness were used to investigate the effect of floral movement on pollinator visits. There is heritable variation in both direct and indirect estimates of floral mobility. The highest insect total visitation times were associated with medium length thin stalks that were visited more frequently and by more insect species. Although mean individual visit durations were less than those of less mobile flowers, this was compensated for by increased visits. Observations of controlled pollinations show that when the visit times are low, so is seed set and therefore low and high mobility flowers might suffer from reduced fitness. Combining these observations provides a mechanism that could be driving stabilizing selection for flower stalk traits, with a trade-off applying between waving to attract pollinators and not being too mobile as to prevent effective pollination. Further evidence for stabilizing selection is provided by the relationship observed in the field between seed set and floral mobility where the highest levels of fitness was associated with intermediate levels of floral waving.     

Do Nest Light Conditions Affect Rejection of Parasitic Eggs? A Test of the Light Environment Hypothesis

Discrimination of foreign eggs is one of the most studied aspects of host defences against avian brood parasites. Although many factors affecting host egg‐recognition processes have already been evaluated, only a few attempts have been made to test the importance of light conditions in microhabitats of host nests. Here, we examined whether the objectively measured nest light environment affects great reed warbler (Acrocephalus arundinaceus) responses towards real common cuckoo (Cuculus canorus) eggs. More specifically, we predicted that parasitic eggs will be rejected with a lower frequency from nests placed in darker conditions than those in lighter conditions. However, we found no effect of the ambient light on egg‐rejection behaviour alone, but the photosynthetically active radiation exhibited a positive interactive effect with chromatic contrast between cuckoo and host eggs. Most rejection events were accomplished when cuckoo eggs of poor mimicry were laid in well‐lit nests. Our study suggests that this phenomenon may have important implications for the evolution of egg mimicry and host egg discrimination. We encourage further testing of the light environment hypothesis in other host species breeding in variable nest microhabitats and light conditions.     

Transformation of Hematite into Magnetite During Dissimilatory Iron Reduction—Conditions and Mechanisms

Magnetite formation during the reduction of nanoparticulate hematite by Shewanella putrefaciens 200R is investigated in media of variable composition, at circumneutral pH and with lactate as electron donor. The relative rates of production of dissolved Fe(II) and Fe(III), aqueous speciation, plus chemical gradients control whether or not magnetite forms in the experiments. High bicarbonate concentrations result in the precipitation of magnetite, presumably by enhancing the non-reductive dissolution of hematite, hence causing the simultaneous production of soluble Fe(III) and Fe(II) in the incubations. Magnetite formation is inhibited when hematite dissolution is slowed down by adsorption of oxyanions (phosphate and sulfate) at the mineral surface, when the reduction of soluble Fe(III) is enhanced by increasing the cell density or adding an electron shuttle (AQS), or when aqueous Fe(II) is complexed by ferrozine. In experiments where hematite suspensions with and without bacteria are separated by a dialysis membrane, magnetite formation occurs mainly in the cell-free portion of the reaction system. Most likely, precipitation of magnetite is favored in the cell-free suspension because of a higher soluble Fe(III) to Fe(II) ratio. The formation of magnetite in the absence of cells further implies that its nucleation is not catalyzed by the bacterial surfaces.     

Does Dormancy Increase Fitness of Bacterial Populations in Time-Varying Environments?

A simple family of models of a bacterial population in a time varying environment in which cells can transit between dormant and active states is constructed. It consists of a linear system of ordinary differential equations for active and dormant cells with time-dependent coefficients reflecting an environment which may be periodic or random, with alternate periods of low and high resource levels. The focus is on computing/estimating the dominant Lyapunov exponent, the fitness, and determining its dependence on various parameters and the two strategies—responsive and stochastic—by which organisms switch between dormant and active states. A responsive switcher responds to good and bad times by making timely and appropriate transitions while a stochastic switcher switches continuously without regard to the environmental state. The fitness of a responsive switcher is examined and compared with fitness of a stochastic switcher, and with the fitness of a dormancy-incapable organism. Analytical methods show that both switching strategists have higher fitness than a dormancy-incapable organism when good times are rare and that responsive switcher has higher fitness than stochastic switcher when good times are either rare or common. Numerical calculations show that stochastic switcher can be most fit when good times are neither too rare or too common. This research was supported by NSF Grant DMS 0414270, Department of Mathematics, Arizona State University, Tempe, AZ.     

Influence of Environmental Conditions on Hyphal Morphology in Pellets of Aspergillus niger: Role of β-N-Acetyl-D-Glucosaminidase

The influence of modifications of the environmental conditions of growth on β-N-acetyl-D-glucosaminidase (EC 3.2.1.30) activity and on hyphal morphological patterns in pellets of Aspergillus niger was studied. It was found that changes in the degree of branching and, to a lesser extent, in the number of bulbous cells were directly related to the activity of the enzyme. Nevertheless, since β-N-acetyl-D-glucosaminidase is not the only enzyme involved in the lytic potential of the fungus, these findings do not exclude the possibility that other enzymes may be involved. Received: 30 December 1998 / Accepted: 9 March 1999     

Does Multimorbidity Influence the Occurrence Rates of Chronic Conditions? A Claims Data Based Comparison of Expected and Observed Prevalence Rates

Objective

Multimorbidity is a complex phenomenon with an almost endless number of possible disease combinations with unclear implications. One important aspect in analyzing the clustering of diseases is to distinguish between random coexistence and statistical dependency. We developed a model to account for random coexistence based on stochastic distribution. We analyzed if the number of diseases of the patients influences the occurrence rates of chronic conditions.

Methods

We analyzed claims data of 121,389 persons aged 65+ using a list of 46 chronic conditions. Expected prevalences were simulated by drawing without replacement from all observed diseases using observed overall prevalences as initial probability weights. To determine if a disease occurs more or less frequently than expected by chance we calculated observed-minus-expected deltas for each disease. We defined clinical relevance as |delta| ≥ 5.0%. 18 conditions were excluded because of a prevalence < 5.0%.

Results

We found that (1) two chronic conditions (e.g. hypertension) were more frequent than expected in patients with a low number of comorbidities; (2) four conditions (e.g. renal insufficiency) were more frequent in patients with many comorbidities; (3) six conditions (e.g. cancer) were less frequent with many comorbidities; and (4) 16 conditions had an average course of prevalences.

Conclusion

A growing extent of multimorbidity goes along with a rapid growth of prevalences. This is for the largest part merely a stochastic effect. If we account for this effect we find that only few diseases deviate from the expected prevalence curves. Causes for these deviations are discussed. Our approach also has methodological implications: Naive analyses of multimorbidity might easily be affected by bias, because the prevalence of all chronic conditions necessarily increases with a growing extent of multimorbidity. We should therefore always examine and discuss the stochastic interrelations between the chronic conditions we analyze.     

Vaccination against Foot-And-Mouth Disease: Do Initial Conditions Affect Its Benefit?

When facing incursion of a major livestock infectious disease, the decision to implement a vaccination programme is made at the national level. To make this decision, governments must consider whether the benefits of vaccination are sufficient to outweigh potential additional costs, including further trade restrictions that may be imposed due to the implementation of vaccination. However, little consensus exists on the factors triggering its implementation on the field. This work explores the effect of several triggers in the implementation of a reactive vaccination-to-live policy when facing epidemics of foot-and-mouth disease. In particular, we tested whether changes in the location of the incursion and the delay of implementation would affect the epidemiological benefit of such a policy in the context of Scotland. To reach this goal, we used a spatial, premises-based model that has been extensively used to investigate the effectiveness of mitigation procedures in Great Britain. The results show that the decision to vaccinate, or not, is not straightforward and strongly depends on the underlying local structure of the population-at-risk. With regards to disease incursion preparedness, simply identifying areas of highest population density may not capture all complexities that may influence the spread of disease as well as the benefit of implementing vaccination. However, if a decision to vaccinate is made, we show that delaying its implementation in the field may markedly reduce its benefit. This work provides guidelines to support policy makers in their decision to implement, or not, a vaccination-to-live policy when facing epidemics of infectious livestock disease.     

Influence of Pollen Nutrition on Honey Bee Health: Do Pollen Quality and Diversity Matter?

Honey bee colonies are highly dependent upon the availability of floral resources from which they get the nutrients (notably pollen) necessary to their development and survival. However, foraging areas are currently affected by the intensification of agriculture and landscape alteration. Bees are therefore confronted to disparities in time and space of floral resource abundance, type and diversity, which might provide inadequate nutrition and endanger colonies. The beneficial influence of pollen availability on bee health is well-established but whether quality and diversity of pollen diets can modify bee health remains largely unknown. We therefore tested the influence of pollen diet quality (different monofloral pollens) and diversity (polyfloral pollen diet) on the physiology of young nurse bees, which have a distinct nutritional physiology (e.g. hypopharyngeal gland development and vitellogenin level), and on the tolerance to the microsporidian parasite Nosema ceranae by measuring bee survival and the activity of different enzymes potentially involved in bee health and defense response (glutathione-S-transferase (detoxification), phenoloxidase (immunity) and alkaline phosphatase (metabolism)). We found that both nurse bee physiology and the tolerance to the parasite were affected by pollen quality. Pollen diet diversity had no effect on the nurse bee physiology and the survival of healthy bees. However, when parasitized, bees fed with the polyfloral blend lived longer than bees fed with monofloral pollens, excepted for the protein-richest monofloral pollen. Furthermore, the survival was positively correlated to alkaline phosphatase activity in healthy bees and to phenoloxydase activities in infected bees. Our results support the idea that both the quality and diversity (in a specific context) of pollen can shape bee physiology and might help to better understand the influence of agriculture and land-use intensification on bee nutrition and health.     

Do Herbivore-Induced Plant Volatiles Influence Predator Migration and Local Dynamics of Herbivorous and Predatory Mites?

If predators lack information on the prey's position, prey have more chance to escape predation and will therefore reach higher population densities. One of the many possible cues that predators may use to find their prey are herbivore-induced plant volatiles. Although their effects on the behaviour of foraging predators have been well studied, little is known about how these prey-related odours affect predator–prey dynamics on a plant. We hypothesise that herbivore-induced plant volatiles provide the major cue eliciting predator arrestment on prey-infested leaves and that the response to these volatiles ultimately leads to lower prey densities. To test this hypothesis experimentally, we created two types of odour-saturated environments: one with herbivore-induced plant volatiles (treatment), and one with green-leaf volatiles (control). An odour-free environment could not be tested because herbivores require plants for population growth. We measured the rate at which predatory mites (Phytoseiulus persimilis) immigrate, emigrate and exploit a single leaf infested by two-spotted spider mites (Tetranychus urticae). The experiments did not show a significant difference between treatment and control. At best, there was a somewhat higher rate of predator (and possibly also prey) emigration in the treatment. The lack of a pronounced difference between treatment and control indicates that at the spatial scale of the experiments random searching for prey was as effective as directional searching. Alternatively, predators were arrested in the prey patch by responding not merely to herbivore-induced plant volatiles, but also to other prey-related cues, such as web and faeces. Based on our current experience we advocate to increase the spatial scale of the experiment (>1m²) and we provide other suggestions for improving the set-up.     

Distribution of Tardigrades within a Moss Cushion: Do Tardigrades Migrate in Response to Changing Moisture Conditions?

The distribution of tardigrades within the layers of the cushion moss Grimmia alpicola Hedwig, 1801 was investigated. The aim of this study was to determine the tardigrade species present within the moss layers during both wet and dry periods and to determine if migration occurred in response to changing moisture conditions. Samples of the moss were removed from concrete caps on brick fence posts before and after rainfall and separated into two sections (top and bottom). The tardigrades from each layer and moisture condition were identified to species. Data for each species were statistically analyzed with a two-way analysis of variance (ANOVA) to compare the numbers of individuals present in the top and bottom layers of the moss under both wet and dry conditions.

Five tardigrade species were identified, including two species new to science: Macrobiotus sp. n.; Milnesium tardigradum Doyère, 1840; Echiniscus viridissimus Peterfi, 1956; Echiniscus perviridis Ramazzotti, 1959; and Echiniscus sp. n. The new species will be described in a forthcoming paper. No significant differences were found in the numbers of individuals of four of the five species in each layer within the moss or for each moisture condition. Only one species, E. viridissimus, was significantly more frequent in the top layer of the moss, regardless of moisture condition.

Migration within the moss cushion was not detected in any of these five species as a result of changes in moisture conditions. In xeric moss species, it may not be beneficial for tardigrades to migrate to avoid desiccation. Instead, they apparently undergo anhydrobiosis in both the top and bottom layers of the moss cushion.     

黄进华 Electron Microscopic Observation of Symbiotic Relationship Between Azolla and Anabaena During the Megaspore Germination and the Sporeling Development of Azolla

The process of establishing symbiotic relationship of Anabaena azollae with its host during the megaspore germination and sporeling development was examined using electron microscope. The observations revealed that most of the Anabaena spores were primarily adhered to the hair cells arisen from the sporeling subsequently introduced into the cavity of the 1st true leaf by the hair ceils. Following the sporeling development, the Anabaena spores were migrated to the newly developing cavities and the branch apex in the same way. The pattern of germination of the Anabaena spore is similar to that of free-living cyanobacteria. Germinating Anabaena spores were only found at shoot apex region and the cavities of the sporeling, 92% of them being onto or near the hair cells which exhibit the ultrastructural characteristics of the transfer cell. The results suggested that Anabaena spore might get the chemical signal stimulating germination or the substance supporting cell multiplication from the host. Some of vegetative cells derived from the Anabaena spore were differentiated in to nitrogen-fixing heterocysts within the cavity. This means that the new generation of the symbiosis between Anabaena and Azolla has begun.     

Do Dietary Habits Influence Trace Elements Release from Fixed Orthodontic Appliances?

The objective was to investigate the effect of dietary habits on the release of Cr and Ni ions from orthodontic appliances by hair mineral analysis. Patients (N = 47) underwent electronic questionnaire survey to investigate the effect of dietary habits on Cr and Ni levels in hair. The research was carried out on hair sampled at the beginning and in the 4th, 8th, and 12th months of the treatment. The content of Cr and Ni in the collected samples was determined by ICP-OES. The study showed that consumption of acidic dietary products may have the effect on increasing the release of Cr and Ni ions from orthodontic appliances. The release of Cr from orthodontic appliances in patients who consumed fruit juice, coffee, yoghurt, and vinegar was higher. The coefficients enabling comparison of metal ions release pattern at a given sampling points were defined. The comparison of the coefficients yielded the information on the possible magnification of metal ions released as the result of the additional factor consumption of acidic food or drink that intensifies metal ions release. The following magnification pattern was found for chromium: coffee (7.57 times) > yoghurt (2.53) > juice (1.86) > vinegar (1.08), and for nickel: vinegar (2.2) > coffee (1.22) > juice (1.05). Yoghurt did not intensify the release of nickel. Concluding, orthodontic patients should avoid drinking/eating coffee, yoghurt, fruit juices, and vinegar.     

Does Endophyte Influence Regrowth of Tall Fescue?

The influence of ecological and environmental factors on theresponse of the mutualistic symbionts Acremonium coenophialum(Morgan-Jones and Gams), and tall fescue ( Festuca arundinacea,Schreb.) has received substantial attention. However, much ofwhat is known about developmental and physiological responseshas been obtained from static or mature canopies and the influenceof defoliation on the symbiota has not been considered in detail.A controlled environment experiment was conducted to assessthe influence of defoliation and endophyte on the regrowth anddevelopment of two tall fescue genotypes and their respectiveendophytes, known to differ in morphology and alkaloid productioncapacity. The response of endophyte infected relative to non-infectedplants was evaluated for measured and calculated parametersfor each defoliation. While the influence of genotype was substantialon virtually all parameters, endophyte interacted with genotypeand defoliation resulting in enhanced plasticity of mutualistsas a response to varying conditions. Endophyte infection influencedleaf mass depending upon genotype, while the relative benefitof endophyte on pseudostem mass was affected by defoliation.Endophyte interacted with genotype to influence relative growthrate and productivity relative to nitrogen concentration whencanopies were clipped, but was less important when canopiesremained uncut. In some instances endophyte gave growth andsize advantage to the host and did not in others. Generalitiesregarding symbiont response to extrinsic factors may be misleading,since responses depend upon the specific mutualism consideredand conditions imposed. Acremonium coenophialum ; Festuca arundinacea ; non-structural carbohydrate; relative growth rate     

Do Mismatches between Pre- and Post-Natal Environments Influence Adult Physiological Functioning?

Purpose

Mismatches between pre- and post-natal environments have implications for disease in adulthood. However, less is known about how this mismatch can affect physiological systems more generally, especially at younger ages. We hypothesised that mismatches between pre- and post-natal environments, as measured by the measures of birthweight and adult leg length, would be associated with poorer biomarker levels across five key physiological systems in young adults.

Methods

Data were collected from 923, 36 year-old respondents from the West of Scotland Twenty-07 Study. The biomarkers were: systolic blood pressure (sBP); forced expiratory volume (FEV₁); glycated haemoglobin (HbA_1c); glomerular filtration rate (eGFR); and gamma-glutamyltransferase (GGT). These biomarkers were regressed against pre-natal conditions (birthweight), post-natal conditions (leg length) and the interaction between pre- and post-natal measures. Sex, childhood socioeconomic position and adult lifestyle characteristics were adjusted for as potential effect modifiers and confounders, respectively.

Results

There were no associations between birthweight and leg length and sBP, FEV₁, HbA_1c, or GGT. Higher birthweight and longer leg length were associated with better kidney function (eGFR). However, there was no evidence for mismatches between birthweight and leg length to be associated with worse sBP, FEV₁, HbA_1c, eGFR or GGT levels (P>0.05).

Conclusions

Our hypothesis that early signs of physiological damage would be present in young adults given mismatches in childhood environments, as measured by growth markers, was not proven. This lack of association could be because age 36 is too young to identify significant trends for future health, or the associations simply not being present.     

Influence of Incubation Conditions on Hydrolysis Efficiency and Iodine Enrichment in Baker’s Yeast

The influence of incubation conditions, enzyme type, hydrolysis time, and potassium iodide concentration on hydrolysis and iodine enrichment were studied in supernatant and pellets of Saccharomyces cervisiae hydrolysates. The type of enzyme used and incubation time significantly influence hydrolysis efficiency and protein concentration in supernatant and pellet. The highest protein hydrolysis efficiency was obtained by 24-h incubation with papain. Significantly lower values were observed for pepsin and autolysis. The potassium iodide concentration influences the iodine content of supernatant and pellet, but not hydrolysis. Iodide enrichment of supernatant and pellet depends on the concentration of iodide using during incubation. High concentration of iodide and long incubation times were the conditions for optimal iodide enrichment and high-protein hydrolysates. The optimal hydrolysis efficiency and iodine enrichment were obtained during 24-h incubation with papain in a 4.5-mM potassium iodide medium. The efficiency reached 98.22% with iodine concentrations of 2,664.91 and 9,200.67 μg/g iodine in pellet and supernatant, respectively.