Do natural enemies really make a difference? Field scale impacts of parasitoid wasps and hoverfly larvae on cereal aphid populations

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Interactions of two species of the genusChenopodium with two production plants—Sugar beet and spring wheat

TwoChenopodium species (C. album L.,C. suecicum J. Murr) were grown under field conditions with sugar beet to assess the weed-caused crop loss, and with spring wheat in a replacement series experiment. The weeds strongly reduced the growth of sugar beet. Dew's competition indexes for the regressions of sugar beet yield on weed density were 6.81 and 3.78 forC. suecicum andC. album respectively. On the other hand, the yield of spring wheat was not affected by the twoChenopodium species owing to early shading of the weeds by the faster growing crop stand.     

Chirped dissipative ion-cyclotron solitons in the Earth’s low-altitude ionospheric plasma with two ion species

Conditions for the excitation of small-scale nonlinear ion-cyclotron gradient-drift dissipative structures in cold ionospheric plasma are considered. The solution for the wave electric field in this structure in the form of a chirped soliton satisfying the equation of the Ginzburg-Landau type is derived in the electrostatic approach. The dissipative structure as a whole represents the chirped soliton accompanied by the comoving quasineutral plasma hump. The possibility of the excitation of two modes of this type (the high- and low-frequency ones) in plasma containing light and heavy ion impurities is considered. The role of electromagnetic corrections and the possible contribution introduced by these structures to the transport processes in the ionosphere are discussed.     

Zinner’s syndrome: report of two cases and review of the literature

Background

Congenital malformations of the seminal vesicle are uncommon, and most of them are cystic malformations. If an insult occurs between the 4th and the 13 h gestational week, the embryogenesis of the kidney, ureter, seminal vesicle, and vas deferens could be altered. Cysts of the seminal vesicle may appear with a mass effect, dysuria, epididymitis, or obstruction of the gastrointestinal and genitourinary tracts. Approximately two thirds of them are associated with ipsilateral renal agenesis, because both the ureteral buds and seminal vesicles originate from the mesonephric (Wolffian) duct. They were first described by Zinner in 1914, and 200 cases of seminal vesicle cysts associated with ipsilateral renal agenesis have been reported in the literature. Most patients with this anomaly are asymptomatic until the third or fourth decade of life. Some cases have nonspecific symptoms such as prostatism, urinary urgency, dysuria, painful ejaculation, and perineal discomfort. Transrectal ultrasonography provides good visualization of the pelvic structures and allows guidance for aspiration of the cysts.

Case presentation

We present two cases of seminal vesicle cyst. The first patient had dysuria, increased frequency of urination, and haematuria. He was operated and benefited from a removal of the cyst with right ureterectomy and left ureteral reimplantation. The second patient had disorder of the digestive transit and he benefited from a laparoscopic removal of the cyst.

Conclusions

Seminal vesicle cysts combined with ipsilateral renal agenesis are rare urological anomalies. Usual symptoms that are caused by the seminal vesicle cysts are bladder irritation and obstruction as well as pain in the perineum and scrotum. Epididymitis is frequently found. Treatment consists to removing the seminal vesicle cyst.

     

Variation of natural reproduction parameters and Crow’s indices in different ethnic groups in the two largest megacities of Russia

Genetic-demographic parameters of natural reproduction in the most numerous ethnic groups of Moscow and St. Petersburg were assessed on the basis of the 2002 All-Russia Population Census data and other sources. The intensity of intragroup selection due to individual differences in fertility in the cohorts of women born in the 1930s–1950s decreased in all ethnic groups studied. It was concluded that, in both megacities, the relaxation of the selection component due to differential fertility almost stopped: the values of the Crow’s index I_f stabilized at 0.3 < I_f < 0.4, which was associated with relative stabilization of the interfamily variance of fertility. The temporal dynamics of the intensity of intergroup selection due to interethnic differences in fertility rates was more complex. It was only recently that this type of selection came into action, since even at the beginning of the 20th century fertility rates in various ethno-territorial and ethno-confessional groups of the population of the Russian Empire were similar (5–6 offspring per marriage). In the subsequent decades, interethnic differentiation in progeny size increased because the reproductive behavior of different population groups underwent “modernization” with uneven speed. In Moscow and St. Petersburg, the intensity of intergroup selection decreased in women birth cohorts of the 1930s–1950s, while it was an order of magnitude lower than the intragroup selection. Currently, the average number of offspring varies among ethnic groups in a narrow range from 1.3 to 1.6. It can be expected that interethnic differences in fertility rates in these megacities will increase again owing to growing numbers of migrants from regions with traditionally high birth rates, resulting in differential natural growth of ethnic groups and the corresponding dynamics of the gene pool of the population.     

Effects of contagious distributions of parasitoid eggs per host and of sampling vagaries on Nicholson’s area of discovery

Summary Hassell andVarley described a negative relationship between the Nicholsonianarea of discovery and parasitoid density that permits coexistence of two or more parasitoid species and yields stability. They ascribed the relationship to “mutual interference” among searching parasitoid adults, leading to a “decreased efficiency”. This matter has recently been studied in more detail byHassell and coworkers. Negative relationships can occur for several reasons. In the present paper it is shown that the negative relation occurs under certain assumptions about the way parasitoid eggs are distributed among hosts. Several “contagious” (or “clustered”) distributions were studied. Those assuming variation in host susceptibility or accessibility (negative binomial and added zeros distributions) yielded negative relations. Those assuming variation in parasitoid aggressiveness and fecundity (Neyman Type A distributions) yielded variable results depending on how the distributions of parasitoids per host and of eggs per parasitoid were combined. It was found that, when analyzing actual data, sampling fluctuations can introduce strong negative relations either with or without “contagion”. In all instances, the relation betweenarea of discovery and parasitoid density is affected by host density and is, in general, not linear. The foregoing findings raise serious questions about thearea of discovery concept. An alternative approach is suggested. The initial phase of this study was supported by National Institute of Health Grant S-Rol-AI0611, under Prof.C. B. Huffaker, Division of Biological Control, Department of Entomology, University of California, Berkeley. The study was completed under National Science Foundation Grant GB38271X. Paper no. 4705 of the Journal Series of the North Carolina Agricultural Experiment Station Raleigh.     

Effects of Different Clay’s Percentages on Improvement of Sand-Clay Mixtures with Microbially Induced Calcite Precipitation

Abstract

Microbially induced calcite precipitation (MICP) is currently appraised for the improvement of sandy soils, but only few studies use it to improve sand-clay mixtures. The effect of contents of kaolin clay and the effect of ions in kaolin clay on bacterial urease activity and productive rates for calcium carbonate were studied. Moreover, sand solidification tests were conducted and the solidifying effects of MICP for sand-clay mixtures were evaluated. The results show that adding kaolin clay has an inhibitory effect on the urease activity of bacteria, and adding too many kaolin clays also decrease the productive rates for calcium carbonate. With adding Al₂O₃ or FeCl₃, urease activity both decreases and it becomes lower with adding more Al₂O₃ or FeCl₃. The permeability of sand columns all decreased gradually with MICP curing. With more kaolin clay, the increasing range of bacterial utilization rates of those with larger particle sizes is bigger. The maximum productive rate for calcium carbonate of samples with smaller particle sizes exists in sample with 5% of kaolin clay while other samples with 7.5% of clay have more calcium carbonate. Sand columns with different sand particle sizes have different suitable amounts of added kaolin clays for MICP solidification.     

Development and parasitization of an aphid’s secondary parasitoid,Dendrocerus laticeps (Hymenoptera: Megaspilidae), on Aphidius colemani (Hymenoptera: Braconidae)

Banker-plant systems using Aphidius species have been employed to control pest aphids in greenhouses growing eggplant and sweet pepper in Japan. However, a strong negative correlation between the occurrence of secondary parasitoids and aphid-control success by this system was reported by Nagasaka et al. (2010). To control secondary parasitoid populations, detailed knowledge of their ecological characteristics is needed. In this paper, the development and parasitization ability of Dendrocerus laticeps (Hedicke) (Hymenoptera: Megaspilidae), a major secondary ectoparasitoid of Aphidius species in Japan, were examined under 25 °C laboratory conditions. The maximum female longevity was about 11 days when honeydew was available. Parasitization occurred only on mummified aphids, and the age of mummified aphids did not influence the ecological value of offspring. The maximum parasitization ability was 18.9 hosts/day estimated by Holling’s disc equation. Possible lifetime fecundity was 100.35. The intrinsic rate of natural increase estimated by the bootstrap method ranged from 0.211 to 0.321, depending on the assumptions made about larval mortality. The countermeasures for avoiding the negative impacts of D. laticeps in a banker-plant system include the development of a refuge for mummified aphids and increasing the temperature around the banker plants.     

Air and surface soil samples – two different pairs of shoes? Comparing the pollen spectrum on different days of the pollen season

The pollen spectra of air and surface soil samples from a rooftop (at 14 m) and from ground level (at 1.6 m) in the suburbs of Vienna (Austria) were compared. Two soil samples and two air samples were taken on four different days to account for possible differences: in winter when no pollination occurred (reference day), in spring during the main flowering of Betula (birch day), in spring/summer during the main flowering of Poaceae (grass day), and in autumn during the main flowering of Ambrosia (ragweed day). Thirty-five different pollen types were used to describe the pollen spectra. Frequencies of certain pollen types reflect a seasonal impact on both the surface soil and air samples and show a similarity between air and soil samples on most of the days. However, the seasonal impact is higher in the air samples and shows a high consistency for ground and rooftop level. Kendall’s tau correlation coefficients further substantiate the similarities of the samples especially for the pollen season days. Exceptions include the winter day when pollination was low and the air samples recorded nearly no pollen at all, and the ragweed day when Ambrosia pollen was abundant in three of four samples but not in the ground surface soil sample. Thus, (1) air and surface pollen samples record similar signals during the pollen season but not during the ragweed and winter season and (2) air and surface pollen samples show the impact of local vegetation also in pollen traps located at different heights.     

Electrooptical properties of the microbial suspensions during a cell’s interaction with the antibodies of a different specificity

The electrooptical abilities of the microbial suspensions during a cells interaction with antibodies (ABs) of a different specificity have been studied on the example of the Azospirillum brasilense Sp245 cells and their interaction with the polyclonal monospecific and polyspecific antibodies. Measuring of the orientational spectra of the cells has been performed using the ELUS electrooptical analyzer. A discrete frequency set of an orienting electric field (740, 1000, 1450, 2000, and 2800 kHz) was used. It has been shown that an interaction of the polyspecific AB with the investigated cells redoubles the value of an electrooptical signal of the cells’ suspension as compared with the monospecific antibodies. These findings can be used for a development a new method of microorganism detection.     

Impact of Dental Atmosphere and Behaviour of the Dentist on Children’s Cooperation

During dental treatment children are usually under psychological pressure. With the Sarnat Behaviour Score five different types of patients can be distinguished. There is no method that measures the impact of dental atmosphere and dentist's behaviour on the young patients' readiness to cooperate. The objective of the present study was the implementation and evaluation of a questionnaire on this subject. Eighty-eight patients participated in this study. In the first part of the new questionnaire personal information was collected. The second part consists of 43 items and investigates the relationship between dentist and patient and reflects the atmosphere of the environment. Statistical analysis was performed using the Chi-square test. There were statistically significant differences between the cooperative and non-cooperative group, as regards the perceived honesty of the dentist, the ability to explain and wish to help. Uncooperative children are significantly more often afraid of the dental environment. Sympathy alone has only a minor effect on children's cooperation. Children should be treated with empathy. Especially younger patients appreciate detailed explanations by the dentist. Children's non-cooperative behaviour results often from their aroused interest in the unknown environment, which causes an unpleasant perception of the whole setting.     

Localisation of esteroproteases in ‘resting’ salivary glands from different species and the effects of the organophosphorus inhibitor E600

Summary The distribution of reaction sites for esteroproteases has been assessed in resting salivary glands from rats, guinea-pigs, cats, dogs and rabbits using the new substrate N-acetyl-l-methionine -naphthyl ester (Lexow et al. 1979). Two main types of activity were observed in the parenchyma. 1) Condensed staining was present on the luminal sides of certain ducts in some, but not all, glands, and this type of staining was always most conspicuous in the submandibular glands of each species. It is likely that this periluminal esteroprotease activity arises from secretory enzymes that will pass into the saliva. Their greater presence in submandibular glands may have association with specialised licking activities. 2) Variable diffuse cytoplasmic staining was present in certain acinar cells from some, but not all, glands. This was most pronounced in the mucous cells of zygomatic glands from dogs. It is considered that the enzymes demonstrated in acinar cells are involved in processing secretory products rather than in being secretory themselves. The possibility that this includes signal peptidase is discussed. Ductal activity in rats, cats and guinea-pigs had some relationship with sites of tryptophan staining but not in rabbits or dogs. Any relationship with acinar staining was less evident. Mast cells, showing strong esteroprotease staining, were present in variable numbers in the different glands. Preliminary attempts to qualify the enzymes being demonstrated were made by using the inhibitor E600. This substance inhibited all activity in acinar cells from each species, and in rabbits and dogs it also inhibited the ductal activity as well. However, in rats and guinea-pigs it had little or no effect on the ductal activity and in cats it had only a small inhibitory effect on the ductal activity. E600 had no obvious inhibitory effects on mast cell activity.We are indebted to Professor O. von Deimling for the substrate, N-acetyl-l-methionine -naphthyl ester, used in this investigation     

The effect of vascular complications of diabetes mellitus on human umbilical cord tissue and the number of Wharton Jelly’s mesenchymal stem cells

Molecular Biology Reports - The current study investigated the change in umbilical cord tissue and the number of markers of Wharton’s jelly mesenchymal stem cells (WJ-MSC) in pregnant women...     

Update on the role of molecular factors and fibroblasts in the pathogenesis of Dupuytren’s disease

The mechanism by which the fibroblast is able to trigger palmar fibromatosis is still not yet fully understood. It would appear certain that the “abnormal” fibroblasts continuously synthesise profibrotic cytokines which are able to determine the activation to myofibroblasts, to stimulate them to the further proliferation and synthesis of other cytokines, to modify the cells’ differentiation and ultrastructural characteristics, as well as the production of matrix and other proteins. Several fibroblast growth factors have been suggested to be responsible of an abnormal cell activation with an aberrantly elevated collagen synthesis and extracellular deposition in Dupuytren’s disease, as TGF-Beta, TNF-Alfa, PDGF, GM-CSF, free radicals, metalloproteinases, sex hormones, gene modified expression, mechanical stimulation. The Authors review the current state of knowledge in the field, by analyzing the role of these cytokines in the palmar fibromatosis.     

A core of rhizosphere bacterial taxa associates with two of the world’s most isolated plant congeners

Plant and Soil - The hydrolysis of organic P in soils is a relevant aspect contributing to the supply P to plants, which is affected by adsorbent capacity and biological properties of soils. This...     

Herbivore functional traits and macroinvertebrate food webs have different responses to leaf chemical compounds of two macrophyte species in a tropical lake’s littoral zone

This research addressed the question of whether invertebrate food web structure varied between a native and an invasive macrophyte leaf species in the littoral zone of a tropical reservoir. We compared macroinvertebrate herbivore functional trait diversity composition with food web structure on the two macrophyte leaves, the invasive white ginger lily (Hedichium coronarium—Zingiberaceae) and the native pickerelweed (Pontederia cordata—Pontederiaceae). We predicted that the herbivore macroinvertebrate trait indices would decrease with macrophyte leaf species due to a lower resource quality with the flow-on effects in the food web structure. We calculated the number of functionally singular species (sing.sp) and herbivore functional trait richness (FRic) indices. For the macroinvertebrate food webs, we calculated the total number of trophic links (L), link density (L/S), connectance (C) and predator–prey ratios using a predator–prey matrix. We analysed the relationship between chemical traits of the macrophyte species’ leaves herbivore traits and food web indices using multivariate regression and Pearson’s correlation. Hedichium coronarium leaves had higher biomass and higher nitrogen content than the native P. cordata, which had higher phosphorus and carbohydrate content. Pontederia cordata leaves were associated with specialist macroinvertebrate species which primarily feed on biofilms (e.g. Ulmeritrus and Scirtidae) and plant leaves (e.g. Beardius). Food webs on P. cordata had lower numbers of trophic links (L), links per species (L/S) and predator–prey ratios. Connectance, which represents food web complexity, was similar between macroinvertebrate assemblages on the two leaf types. Our study suggests that chemical compounds of macrophyte leaves quality may have potential flow-on effects on food web structure.     

Assessment of the Efficacy of Solutes from Extremophiles on Protein Aggregation in Cell Models of Huntington’s and Parkinson’s Diseases

Protein misfolding and deposition in the brain are implicated in the etiology of numerous neurodegenerative disorders. Here, organic solutes characteristic of microorganisms adapted to hot environments, were tested on experimental cell models of Huntington’s and Parkinson’s diseases. Diglycerol phosphate, di-myo-inositol phosphate, mannosylglycerate, and mannosylglyceramide were not toxic to the cells, at 10 mM concentration, but caused a decrease in cell density, which suggested an effect on proliferation. In contrast, mannosyl-lactate, an artificial analogue of mannosylglycerate, had a negative impact on cell viability. Concerning protein aggregation, inclusions of mutant huntingtin were reduced in the presence of diglycerol phosphate and di-myo-inositol phosphate, increased with mannosylglycerate, while mannosyl-lactate and mannosylglyceramide had no significant effect. α-Synuclein aggregation was not affected by the solutes tested, except for di-myo-inositol phosphate that led to a slight increased percentage of cells displaying visible aggregates. These solutes might be useful in the development of therapies for protein misfolding diseases.