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91.
Samuel Pineda Manuel Medina José I. Figueroa Thomas J. Henry Laura V. Mena Juan M. Chavarrieta 《Biocontrol Science and Technology》2016,26(8):1073-1086
The life cycle and several life parameters of the zoophytophagous predator Engytatus varians (Distant) (Heteroptera: Miridae), including nymphal growth according to Dyar’s rule, were examined in the laboratory. The egg, nymph (five instars), and adult stages were 9.20, 17.36, and 19.02?d in length, respectively. The growth ratio for nymphs was consistent with Dyar’s rule based on the lengths of the femora of the forelegs, the tibiae and femora of the middle legs, and the antennae. Some biological characteristics of E. varians were also evaluated when the mirid was fed three different diets (B. cockerelli third instars, Sitotroga cerealella Olivier [Lepidoptera: Gelechiidae] eggs, and a mixture of both instars and eggs). The length of the nymphal stage was three days longer on a diet of only S. cerealella eggs than when the mirids were fed the third instars of B. cockerelli only or a mixture of both. The sex ratio was not affected by the type of diet. Nymphs of E. varians consumed B. cockerelli nymphs (80–85) when fed third instars only and third instars?+?S. cerealella eggs, respectively. The potential use of this predator as a biological control agent of B. cockerelli is discussed. 相似文献
92.
Mg2+ can potentially influence bacterial adhesion directly through effects on electrostatic interactions and indirectly by affecting physiology-dependent attachment processes. However, the effects of Mg2+ on biofilm structure are largely unknown. In this study, Pseudomonas fluorescens was used to investigate the influence of Mg2+ concentration (0, 0.1 and 1.0 mM MgCl2) on biofilm growth. Planktonic and attached cells were enumerated (based on DAPI staining) while biofilm structures were examined via confocal laser scanning microscopy and three-dimensional structures were reconstructed. Mg2+ concentration had no influence on growth of planktonic cells but, during biofilm formation, Mg2+ increased the abundance of attached cells. For attached cells, the influence of Mg2+ concentration changed over time, suggesting that the role of Mg2+ in bacterial attachment is complex and dynamic. Biofilm structures were heterogeneous and surface colonization and depth increased with increasing Mg2+ concentrations. Overall, for P. fluorescens, Mg2+ increased initial attachment and altered subsequent biofilm formation and structure. 相似文献
93.
Seasonal tropical forests exhibit a great diversity of leaf exchange patterns. Within these forests variation in the timing
and intensity of leaf exchange may occur within and among individual trees and species, as well as from year to year. Understanding
what generates this diversity of phenological behaviour requires a mechanistic model that incorporates rate-limiting physiological
conditions, environmental cues, and their interactions. In this study we examined long-term patterns of leaf flushing for
a large proportion of the hundreds of tree species that co-occur in a seasonal tropical forest community in western Thailand.
We used the data to examine community-wide variation in deciduousness and tested competing hypotheses regarding the timing
and triggers of leaf flushing in seasonal tropical forests. We developed metrics to quantify the nature of deciduousness (its
magnitude, timing and duration) and its variability among survey years and across a range of taxonomic levels. Tree species
varied widely in the magnitude, duration, and variability of leaf loss within species and across years. The magnitude of deciduousness
ranged from complete crown loss to no crown loss. Among species that lost most of their crown, the duration of deciduousness
ranged from 2 to 21 weeks. The duration of deciduousness in the majority of species was considerably shorter than in neotropical
forests with similar rainfall periodicity. While the timing of leaf flushing varied among species, most (∼70%) flushed during
the dry season. Leaf flushing was associated with changes in photoperiod in some species and the timing of rainfall in other
species. However, more than a third of species showed no clear association with either photoperiod or rainfall, despite the
considerable length and depth of the dataset. Further progress in resolving the underlying internal and external mechanisms
controlling leaf exchange will require targeting these species for detailed physiological and microclimatic studies. 相似文献
94.
Alicia M. Waters Laura L. Stafman Evan F. Garner Smitha Mruthyunjayappa Jerry E. Stewart Gregory K. Friedman Jennifer M. Coleman James M. Markert G. Yancey Gillespie Elizabeth A. Beierle 《Translational oncology》2016,9(5):419-430
Rhabdomyosarcoma (RMS), a tumor of skeletal muscle origin, is the most common sarcoma of childhood. Despite multidrug chemotherapy regimens, surgical intervention, and radiation treatment, outcomes remain poor, especially in advanced disease, and novel therapies are needed for the treatment of these aggressive malignancies. Genetically engineered oncolytic viruses, such as herpes simplex virus-1 (HSV), are currently being explored as treatments for pediatric tumors. M002, an oncolytic HSV, has both copies of the γ134.5 gene deleted, enabling replication in tumor cells but thwarting infection of normal, postmitotic cells. We hypothesized that M002 would infect human RMS tumor cells and lead to decreased tumor cell survival in vitro and impede tumor growth in vivo. In the current study, we demonstrated that M002 could infect, replicate in, and decrease cell survival in both embryonal (ERMS) and alveolar rhabdomyosarcoma (ARMS) cells. Additionally, M002 reduced xenograft tumor growth and increased animal survival in both ARMS and ERMS. Most importantly, we showed for the first time that repeated dosing of oncolytic virus coupled with low-dose radiation provided improved tumor response in RMS. These findings provide support for the clinical investigation of oncolytic HSV in pediatric RMS. 相似文献
95.
Scott Davis Stephanie Propp Susan M. Freier Laura E. Jones Martin J. Serra Garth Kinberger Balkrishen Bhat Eric E. Swayze C. Frank Bennett Christine Esau 《Nucleic acids research》2009,37(1):70-77
Chemically modified antisense oligonucleotides (ASOs) are widely used as a tool to functionalize microRNAs (miRNAs). Reduction of miRNA level after ASO inhibition is commonly reported to show efficacy. Whether this is the most relevant endpoint for measuring miRNA inhibition has not been adequately addressed in the field although it has important implications for evaluating miRNA targeting studies. Using a novel approach to quantitate miRNA levels in the presence of excess ASO, we have discovered that the outcome of miRNA inhibition can vary depending on the chemical modification of the ASO. Although some miRNA inhibitors cause a decrease in mature miRNA levels, we have identified a novel 2′-fluoro/2′-methoxyethyl modified ASO motif with dramatically improved in vivo potency which does not. These studies show there are multiple mechanisms of miRNA inhibition by ASOs and that evaluation of secondary endpoints is crucial for interpreting miRNA inhibition studies. 相似文献
96.
Laura J. Richards 《Journal of experimental marine biology and ecology》1983,73(3):213-224
Adults of the staphylinid beetle Thinopinus pictus LeConte live on sand beaches where they are ambush predators of intertidal amphipods Orchestoidea californiana (Brandt). Peak activity for beetles was found to occur near dark each night, whereas peak activity for amphipods varied with the tidal cycle. Consequently, beetles often foraged when amphipods were inactive. Successful capture of amphipods on each night is not critical to beetle survival, however, as beetles fed at 2-day and 4-day intervals had high survival rates in laboratory experiments.Activity patterns differed between male and female beetles. Male beetles fed less, but were active on more nights and for longer periods each night than female beetles. It is suggested that the timing of foraging activity is determined by the need to find mates as well as food. 相似文献
97.
98.
Miquel Barbera Laura Escriva Jorge Mariano Collantes-Alegre Giuseppe Meca Ezio Rosato David Martinez-Torres 《Insect Science》2020,27(2):224-238
Aphids display life cycles largely determined by the photoperiod.During the warm long-day seasons.most aphid species reproduce by viviparous parthenogenesis.The shortening of the photoperiod in autumn induces a switch to sexual reproduction.Males and sexual females mate to produce overwintering resistant eggs.In addition to this full life cycle(holocycle),there are anholocyelic lineages that do not respond to changes in photoperiod and reproduce continuously by parthenogenesis.The molecular or hormonal events that trigger the scasonal response(i.c,induction of the sexual phenotypes)are still unknown.Although circadian synthesis of melatonin is known to play a key role in vertebrate photoperiodism,the involvement of the circadian clock and/or of the hor-mone melatonin in insect seasonal responses is not so well established.Here we show that melatonin levels in the aphid Acyrthosiphon pisum are significantly higher in holocyclice aphids reared under short days than under long days,while no differences were found between anholoeyelic aphids under the same conditions.We also found that melatonin is localized in the aphid suboesophageal ganglion(SOG)and in the thoracic ganglionic mass(TGM).In analogy to vertcbrates,insect-type arylalkxylamine N-acetyltransferases(i-AANATs)are thought to play a key role in melatonin synthesis.We measured the expression of four I-AANAT genes identified in A.pisum and localized two of them in situ in the insect central nervous systems(CNS).Levels of expression of these genes were compatible with the quantities of melatonin observed.Moreover,like melatonin,expression of these genes was found in the SOG and the TGM. 相似文献
99.
100.