Sexual performance of male mosquito Aedes albopictus

Issues of male fertility must be addressed to support the development of a sterile insect technique (SIT) programme for the control of Aedes albopictus Skuse (Diptera: Culicidae) populations on Reunion Island in the Indian Ocean. The mating ability of a local strain of Ae. albopictus was tested using several batches of females and different cage sizes under laboratory conditions. Individual males were able to inseminate up to 14 females at an average of 9.5 females per male when exposed to 20 females over 7 days. Males filled between three and 27 spermathecal capsules at an average of 15.5 capsules per male. The average number of females inseminated per male was 5.3 when two virgin females were introduced to one male and replaced every day for 12 days, and 8.6 when 10 virgin females were introduced to one male and replaced every day for 14 days. A continuous decrease in the number of both inseminated females and filled spermathecal capsules was observed over time, until no mating occurred after 14 days. The high number of females inseminated by one male and the duration of male activity may have strong implications for SIT control of mosquitoes.     

Dynamic ¹³C/¹ H NMR imaging uncovers sugar allocation in the living seed

Seed growth and accumulation of storage products relies on the delivery of sucrose from the maternal to the filial tissues. The transport route is hidden inside the seed and has never been visualized in vivo. Our approach, based on high‐field nuclear magnetic resonance and a custom made ¹³C/¹H double resonant coil, allows the non‐invasive imaging and monitoring of sucrose allocation within the seed. The new technique visualizes the main stream of sucrose and determines its velocity during the grain filling in barley (Hordeum vulgare L.). Quantifiable dynamic images are provided, which allow observing movement of ¹³C‐sucrose at a sub‐millimetre level of resolution. The analysis of genetically modified barley grains (Jekyll transgenic lines, seg8 and Risø13 mutants) demonstrated that sucrose release via the nucellar projection towards the endosperm provides an essential mean for the control of seed growth by maternal organism. The sucrose allocation was further determined by structural and metabolic features of endosperm. Sucrose monitoring was integrated with an in silico flux balance analysis, representing a powerful platform for non‐invasive study of seed filling in crops.     

胸内正压对正常人左室功能影响及其力学原理

目的:探讨胸内正压对正常人左室射血及充盈的影响及其力学原理。方法:超声心动图观测30例正常人初始时与标准乏氏动作张力期10s时左室舒张末容积(LVEDV)、左室收缩末容积(LVESV)、每搏量(SV)、射血分值(EF)、流入道血流速度(E峰、A峰)、E/A值、二尖瓣环舒张早期运动速度(e)及舒张早期充盈压(E/e)的变化。结果:与初始时比较,标准乏氏动作张力期LVEDV、LVESV及SV减低而心率(HR)增快(P均<0.001),EF值增加,但无统计学意义(P>0.05);E峰与E/A值减低(P均<0.05);e没有变化(P>0.05),E/e值减低(P<0.05)。结论:胸内正压对左室游离壁的力学作用促进了左室收缩运动而阻碍了左室舒张运动,会引起EF值增加,E峰及E/A值减低;2,胸内正压降低了肺静脉系统与心脏的跨壁压力,增加了血流阻力也是导致肺静脉系统与左室血液回流减少,E峰减低,E/e值减低的一个原因。     

Expandable spermatheca influences sperm storage in the simultaneously hermaphroditic snail Arianta arbustorum

Summary

In many simultaneously hermaphroditic land snail species, the sperm storage organ (spermatheca) is highly structured, suggesting that the female function might be able to influence offspring paternity. Physical properties of the sperm storage organ, including its initial size and sperm storage capacity, may also affect fertilization patterns in multiply mated snails. We examined the structure, volume and tubule length of empty spermathecae in the land snail, Arianta arbustorum, and assessed differences in spermatheca size following a single copulation. The number of spermathecal tubules ranged from 2–7, but was not correlated with the volume of empty spermathecae. The volume of sperm stored in the spermatheca after a copulation was correlated with neither the number of spermathecal tubules nor copulation duration. Mean spermathecal volume more than doubled between two and thirty-six hours after sperm uptake, but the length of the spermathecal tubules did not change. Interestingly, the volume of sperm stored in the spermatheca seems not to be related to the size of the spermatophore and thus not to the number of sperm received (= allosperm). The amount of allosperm digested in the bursa copulatrix was highly variable and no significant relationship with the size of the spermatophore received was found. These findings suggest that numerical aspects of sperm transfer are less important in influencing fertilization success of sperm in A. arbustorum than properties of the female reproductive tract of the sperm receiver.     

Histological Techniques to Improve Testing of Pulpal Response of Teeth to Filling Material

Two fixation fluids, two fixation techniques and two embedding methods were investigated for their effects on the quality of sections of teeth for pulpal response to filling materials to improve evaluation of pulpal responses. Sections from 32 baboon teeth were prepared, half with experimental cavities and half without, using either 10% formaldehyde or 4% glutaraldehyde, longitudinal tooth splitting or removal of the tooth apex, and paraffin or K plast resin embedding; decalcification in a formic acid mixture was a constant throughout. Histometric analysis showed that paraffin embedding produced less shrinkage than the K Plast resin embedding although the difference was not statistically significant. Six parameters of separation at the pu1p:dentine interface were studied: embedding, fixative, presence or absence of a cavity, cutting technique and individual animal tooth type. Statistical investigation revealed that fixative, cutting technique, and fixative and cutting technique combined had significant influences on the separation artifact. Of the combinations tested the choice of embedding method depends on which of the two artifacts, shrinkage or separation, is more adverse in the opinion of the investigator. Four percent glutaraldehyde together with the longitudinal split technique of fixation. processed by either K Plast resin embedding or paraffin embedding produced satisfactory pulpal sections.     

The important but weakening maize yield benefit of grain filling prolongation in the US Midwest

A better understanding of recent crop yield trends is necessary for improving the yield and maintaining food security. Several possible mechanisms have been investigated recently in order to explain the steady growth in maize yield over the US Corn‐Belt, but a substantial fraction of the increasing trend remains elusive. In this study, trends in grain filling period (GFP) were identified and their relations with maize yield increase were further analyzed. Using satellite data from 2000 to 2015, an average lengthening of GFP of 0.37 days per year was found over the region, which probably results from variety renewal. Statistical analysis suggests that longer GFP accounted for roughly one‐quarter (23%) of the yield increase trend by promoting kernel dry matter accumulation, yet had less yield benefit in hotter counties. Both official survey data and crop model simulations estimated a similar contribution of GFP trend to yield. If growing degree days that determines the GFP continues to prolong at the current rate for the next 50 years, yield reduction will be lessened with 25% and 18% longer GFP under Representative Concentration Pathway 2.6 (RCP 2.6) and RCP 6.0, respectively. However, this level of progress is insufficient to offset yield losses in future climates, because drought and heat stress during the GFP will become more prevalent and severe. This study highlights the need to devise multiple effective adaptation strategies to withstand the upcoming challenges in food security.     

Elucidation of the Sodium‐Storage Mechanism in Hard Carbons

Hard carbons (HCs) are the most promising candidate anode materials for emerging Na‐ion batteries (NIBs). HCs are composed of misaligned graphene sheets with plentiful nanopores and defects, imparting a complex correlation between its structure and sodium‐storage behavior. The currently debated mechanism of Na⁺‐ion insertion in HCs hinders the development of high‐performance NIBs. In this article, ingenious and reliable strategies are used to elaborate the correlation between the structure and electrochemical performance and further illuminate the sodium‐storage mechanism in HCs. First, filling sulfur into the micropores of HCs can remove the low‐voltage plateau, providing solid evidence for its association with the pore‐filling mechanism. Along with the decreased concentration of defects/heteroatoms at higher treatment temperature, the reduced sloping capacity confirms the adsorption mechanism in the sloping region. Finally, the similar sodium‐insertion behaviors of HCs with ether‐based and ester‐based electrolytes indicate that no Na⁺ ions intercalate between the graphene layers. The determined adsorption‐pore‐filling mechanism encourages the design of more efficient HC anode materials with high capacity for high‐energy NIBs.     

Carbon conversion efficiency and central metabolic fluxes in developing sunflower (Helianthus annuus L.) embryos

The efficiency with which developing sunflower embryos convert substrates into seed storage reserves was determined by labeling embryos with [U-(14)C6]glucose or [U-(14)C5]glutamine and measuring their conversion to CO2, oil, protein and other biomass compounds. The average carbon conversion efficiency was 50%, which contrasts with a value of over 80% previously observed in Brassica napus embryos (Goffman et al., 2005), in which light and the RuBisCO bypass pathway allow more efficient conversion of hexose to oil. Labeling levels after incubating sunflower embryos with [U-(14)C4]malate indicated that some carbon from malate enters the plastidic compartment and contributes to oil synthesis. To test this and to map the underlying pattern of metabolic fluxes, separate experiments were carried out in which embryos were labeled to isotopic steady state using [1-(13)C1]glucose, [2-(13)C1]glucose, or [U-(13)C5]glutamine. The resultant labeling in sugars, starch, fatty acids and amino acids was analyzed by NMR and GC-MS. The fluxes through intermediary metabolism were then quantified by computer-aided modeling. The resulting flux map accounted well for the labeling data, was in good agreement with the observed carbon efficiency, and was further validated by testing for agreement with gas exchange measurements. The map shows that the influx of malate into oil is low and that flux through futile cycles (wasting ATP) is low, which contrasts with the high rates previously determined for growing root tips and heterotrophic cell cultures.     

一种便捷而经济的显微注射针填充方法

目的:建立一种便捷而经济的将DNA溶液填充至显微注射针的方法,以提高显微注射法转基因的效率。方法:将通常用于转移胚胎的口吸管稍加改进,吸取DNA溶液,从尾部直接注入显微注射针。结果:采用本方法填充显微注射针,可在2～5min完成DNA填充。结论:与传统方法相比,本法经济而高效,可加快显微注射法制作转基因动物的实验进程。