Nematicides Increase Grain Yields in Spring Wheat Cultivars and Suppress Plant-Parasitic and Bacterial-Feeding Nematodes

Grain yields of spring wheat (Triticum aestivum L. cvs. AC Barrie, AC Walton, AC Wilmot, Belvedere, Glenlea) in field plots over a 3-year period were increased (P < 0.001) by an average of 0.56 (25.1%) and 1.17 (52.5%) tonnes/ha in comparison to untreated check plots when aldicarb at 2.24 kg or fosthiazate at 13.5 a.i./ha, respectively, were broadcast and incorporated into the soil to suppress nematodes. The planned F test using orthogonal coefficients indicated that the mean response of grain yields to nematicide treatments of AC Barrie and Glenlea, which are grown primarily in the prairie provinces of Canada, was greater (48.5%) than the mean response of Belvedere, AC Walton, and AC Wilmot (33.7%), which are more common in the Maritime region of Canada (P < 0.001). Root lesion nematodes (primarily Pratylenchus penetrans) in wheat roots and in root zone soil at harvest were reduced by the nematicide applications (P < 0.001). Bacterial-feeding nematodes (primarily Diplogaster lheritieri (Maupas)) in root zone soil were also suppressed by fosthiazate (P < 0.01) but not by aldicarb. These data indicate that root lesion nematodes cause substantial yield losses in spring wheat in the Maritime region of Canada.     

Assaying Predatory Feeding Behaviors in Pristionchus and Other Nematodes

This protocol provides multiple methods for the analysis and quantification of predatory feeding behaviors in nematodes. Many nematode species including Pristionchus pacificus display complex behaviors, the most striking of which is the predation of other nematode larvae. However, as these behaviors are absent in the model organism Caenorhabditis elegans, they have thus far only recently been described in detail along with the development of reliable behavioral assays ¹. These predatory behaviors are dependent upon phenotypically plastic but fixed mouth morphs making the correct identification and categorization of these animals essential. In P. pacificus there are two mouth types, the stenostomatous and eurystomatous morphs ², with only the wide mouthed eurystomatous containing an extra tooth and being capable of killing other nematode larvae. Through the isolation of an abundance of size matched prey larvae and subsequent exposure to predatory nematodes, assays including both "corpse assays" and "bite assays" on correctly identified mouth morph nematodes are possible. These assays provide a means to rapidly quantify predation success rates and provide a detailed behavioral analysis of individual nematodes engaged in predatory feeding activities. In addition, with the use of a high-speed camera, visualization of changes in pharyngeal activity including tooth and pumping dynamics are also possible.     

Effects of Interactions of Auxin-Producing Bacteria and Bacterial-Feeding Nematodes on Regulation of Peanut Growths

The influences of an IAA (indole-3-acetic acid)-producing bacterium (Bacillus megaterium) and two bacterial-feeding nematodes (Cephalobus sp. or Mesorhabditis sp.) on the growth of peanut (Arachis hypogaea L. cv. Haihua 1) after various durations of time were investigated in natural soils. The addition of bacteria and nematodes and incubation time all significantly affected plant growth, plant root growth, plant nutrient concentrations, soil nutrient concentrations, soil microorganisms and soil auxin concentration. The addition of nematodes caused greater increases in these indices than those of bacteria, while the addition of the combination of bacteria and nematodes caused further increases. After 42-day growth, the increases in soil respiration differed between the additions of two kinds of nematodes because of differences in their life strategies. The effects of the bacteria and nematodes on the nutrient and hormone concentrations were responsible for the increases in plant growth. These results indicate the potential for promoting plant growth via the addition of nematodes and bacteria to soil.     

Three New Species of Predatory Nematodes (Dorylaimida: Actinolaimoidea) from Korea

Three new species of predatory nematodes belonging to family Actinolaimidae, superfamily Actinolaimoidea, order Dorylaimida are described and illustrated. Westindicus sanaensis sp. n. has a body 1.9–2.4mm long; b = 3.7–4.3; c = 8.1–8.5; odontostyle 26.5–28.0μm long; spicules 71–74μm long; ventromedian supplements 15 and comes close to Westindicus cheongsongensis Choi et al, 1998 and Westindicus keralaensis Khan et al., 1994. Egtitus koriensis sp. n. is 1.8–2.0 mm long; b = 3.4–4.1; c = 14–18; odontostyle 20–21 μm, and comes close to Egtitus elaboratus (Cobb, 1906) Thorne, 1967; Egtitus itanagrus Khan et al., 1994 and Egtitus adhricus Khan & Jairajpuri, 1994. Stopractinca glandulus sp. n. is 2.3–2.4 mm long; b = 4.0–4.1; c = 11–12; odontostyle 26–28μm and differs from other two known species viz., Stopractincta orientalis Khan et al., 1994 and Stopractincta malnadensis Dhanam et al., 1994 in having very thick body cuticle and longer cardia, and in the presence of a gland at the base of oesophagus.     

Size Differences Among Root-knot Nematodes on Resistant and Susceptible Alyceclover Genotypes

The influence of plant resistance on the size of individual root-knot nematodes was determined in greenhouse experiments. Five genotypes of alyceclover were inoculated with second-stage juveniles of Meloidogyne incognita race 3 or M. arenaria race 1. Plants were harvested at selected intervals and stained for detection of the nematodes, which were dissected from the roots. Length, width, and sagittal-sectional area of each animal were measured using an image-analysis system, and areas of nematodes in all stages were compared at different times and across alyceclover lines. Nematodes feeding on roots of resistant lines were consistently smaller than those on susceptible plants, with significant differences in growth detected after the final molt. Similar results were observed with both nematode species.     

Behavioral Differences between Archaic and Modern Humans in the Levantine Mousterian

Early modern and archaic humans are associated with similar lithic industries in the Middle Paleolithic of the southern Levant, but new data suggest that they used the environment in different ways. Evidence from analyses of seasonally deposited increments of the teeth of the animals they hunted suggests that modern humans primarily practiced a strategy ofcirculating seasonal mobility, while archaic humans in the same region 30,000 years later were more residentially mobile. Analyses of their lithic hunting technology further suggest that archaic humans hunted more frequently than did modern humans. We argue that this greater hunting intensity may have been a strategy for coping with the consequences of resource biodepletion resulting from long-term, multiseasonal occupation of sites. These behavioral contrasts may be related to some of the morphological differences between early modern and archaic humans.     

Rewiring and regulation of cross-compartmentalized metabolism in protists

Plastid acquisition, endosymbiotic associations, lateral gene transfer, organelle degeneracy or even organelle loss influence metabolic capabilities in many different protists. Thus, metabolic diversity is sculpted through the gain of new metabolic functions and moderation or loss of pathways that are often essential in the majority of eukaryotes. What is perhaps less apparent to the casual observer is that the sub-compartmentalization of ubiquitous pathways has been repeatedly remodelled during eukaryotic evolution, and the textbook pictures of intermediary metabolism established for animals, yeast and plants are not conserved in many protists. Moreover, metabolic remodelling can strongly influence the regulatory mechanisms that control carbon flux through the major metabolic pathways. Here, we provide an overview of how core metabolism has been reorganized in various unicellular eukaryotes, focusing in particular on one near universal catabolic pathway (glycolysis) and one ancient anabolic pathway (isoprenoid biosynthesis). For the example of isoprenoid biosynthesis, the compartmentalization of this process in protists often appears to have been influenced by plastid acquisition and loss, whereas for glycolysis several unexpected modes of compartmentalization have emerged. Significantly, the example of trypanosomatid glycolysis illustrates nicely how mathematical modelling and systems biology can be used to uncover or understand novel modes of pathway regulation.     

Behavioral and Physiological Differences between Two Parapatric Heliconius Species1

The behavior and physiology of two parapatric sibling species, i Heliconius erato cyrbia Godt. and H. himera Hew., were investigated to assess if environmental adaptation enabled stable morphological, genetic, and ecological differences to exist in the face of hybridization. Morning and evening activity, egg production, and larval development time of H. himera and H. erato in insectaries were recorded; individuals were collected in allopatry and in sympatry from a hybrid zone in which the species overlapped. Studies were performed at ambient conditions within the natural range of H. himera. H. himera was considerably more active than H, erato flying earlier in the morning and later in the evening, even when both species were collected in sympatry. Similarly, H. himera laid more eggs, and the hatched larvae developed more rapidly. The results suggest that physiological constraints are an important selective force that may have been important in speciation and counteracts hybridization in the maintenance of the H. himeral H. erato contact zone. Ecological selection, arising from adaptation to low temperatures, may help explain the competitive exclusion of H. erato by H. himera in the drier, cooler montane habitat favored by the latter species.     

Predatory Cues Influence the Behavioral Responses and Metamorphic Traits of Polypedates maculatus(Anura: Rhacophoridae)

Mechanisms of predator detection and the influence of the presence of nonlethal predators on antipredator defense behavior and metamorphic traits were studied in the Indian tree frog, Polypedates maculatus. Exposure of P. maculatus tadpoles to chemical cues of caged predator(crabs, Barytelphusa spp.) fed with either conspecific or heterogeneric tadpoles, or were starved elicited defense behavior(by avoiding predator zone) in them. Such a behavior was not evident when exposed to predators housed in a glass beaker(visual cues). Both early(Gosner stage 27–28) and later(Gosner stage 35–36) stage tadpoles when exposed to caged predators(fed with conspecific tadpoles), prey tadpoles spent less time swimming and remained motionless for longer periods. Yet, the time spent by prey in feeding was unaffected. Further, the predator avoidance behavior exhibited by them was of the same intensity regardless of whether the caged predators were fed or starved implying the influence of predator's kairomones. Tadpoles reared with caged predator reached the metamorphic climax stage(MC stage; Gosner stage 42) earlier than those reared without a predator. Size at emergence(Gosner stage 46) was comparable in both the groups. The findings suggest that P. maculatus tadpoles assess predation risk chiefly by sensing kairomones of the predator in eliciting antipredator defense behaviors. Accelerated development and early metamorphosis without any compromise of the size at emergence may be due to their unaltered feeding activity.     

Intrinsic Behavioral and Physiological Differences Among Laboratory Populations of Prairie Deermice

The emphasis of this presentation is that social behavior isbasically involved in the curtailment of growth of laboratorypopulations of prairie deermice through inhibiting influenceson the reproductive development and function of population animals.Reproductive inhibition is not directly related to the numbersof animals present per se since physiological characteristicsare similar between animals from populations differing widelyin density under identical conditions of the physical environment.Thus, density should be interpreted relative to social or otherbehavioral factors and we should think of animals in a populationin a qualitative as well as a quantitative sense. Populationgrowth is controlled either by cessation of reproduction orby mortality of young and while 95% of the young remain reproductivelyimmature and fail to reproduce, the weights and characteristicsof their reproductive organs differ dependent upon the mechanismby which population growth is curtailed. Mechanisms of growthcurtailment thus develop intrinsically to each population andinvolve communication through one or more of the senses of touch,smell, sight, hearing or taste. My data suggest that tactilecues from population animals (not necessarily overt aggression)may be of major importance in producing the reproductive retardationobserved although chemosignals or other stimuli such as visualor auditory cues may act to slow reproductive recovery of inhibitedanimals. Data presented support the contention of a behavioral-physiologicalrelationship distinct for each population.     

Rewiring of the Fruit Metabolome in Tomato Breeding

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雄性大熊猫对化学信息行为反应的年龄差异

化学通讯对哺乳动物的生存和繁殖起着重要作用。研究了雄性大熊猫(Ailuropoda melanoleuca)对同伴个体尿液气味行为反应的发育模式。结果显示,在成年雌性个体的尿液气味刺激下,雄性个体表现显著多的嗅闻行为和嗅闻/舔舐环境行为,但是嘶咬气味刺激物的行为明显减少。在雌性个体的尿液气味刺激下,不同年龄段的雄性个体行为表现不同,成年雄性个体表现较亚成年和幼年个体显著多的舔舐行为。此外,成年个体和亚成年个体均表现较多的嗅闻/舔舐环境行为,而幼年个体则无该行为表现。幼年个体较成年和亚成年个体表现显著多的气味涂抹行为,而且嘶咬气味刺激物的时间较亚成年个体显著多。幼年个体和亚成年个体对雌性和雄性个体尿液气味刺激的行为反应不存在显著差异。研究结果表明,雄性大熊猫对同种个体尿液中化学信息的行为反应呈现出年龄差异。     

钝叶榕三种榕小蜂的关键形态和行为差异研究

比较钝叶榕三种同步进果的榕小蜂——钝叶榕传粉榕小蜂、杨氏金小蜂和Lipothymussp.的关键形态,结合它们的进果行为,分析非传粉榕小蜂的形态适应性和依赖传粉榕小蜂进果的原因。结果表明,杨氏金小蜂和Li-pothymussp.的胸部、前后足均趋同于钝叶榕传粉榕小蜂,但两者体表较为光滑,有鳞片状刻纹,少毛,且触角第三部分未衍生出刺突形结构,下颚也无骨板。钝叶榕传粉榕小蜂利用刺突和下颚来撬动苞片,形成微小开口,这一过程约耗费总进果时间的2/3。无论钝叶榕传粉榕小蜂是否进入果腔,一旦苞片处形成开口,杨氏金小蜂和Lipothymussp.即可顺利进入,进入果腔的时间无显著的差异。因此,缺少刺突形结构和骨板是杨氏金小蜂和Lipothymussp.不能独自进果的关键,也意味两者进果必须依赖钝叶榕传粉榕小蜂。     

Rewiring Mid1p-Independent Medial Division in Fission Yeast

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笼养东北虎雌雄行为差异的比较

1998年4月－2001年3月在哈尔滨动物园,采用瞬时扫描取样法和全事件取样法对5只笼养东北虎（3雌2雄）的昼夜行为时间分配及活动规律进行了研究。结果表明：东北虎的睡眠、卧息、运动和其他行为在时间分配上两性存在一定差异,即雌性的睡眠和卧息时间比雄性多,雌性的运动和其他行为时间比雄性少;但摄食行为的时间分配相差不大。两性日活动规律的差异为雄性的睡眠高峰主要在夜晚,卧息较雌性少且相对集中,运动出现和结束的时间较雌性延迟约1h。对两性及不同个体行为时间分配的单因素方差分析发现,不同个体间仅运动存在显著差异（P＜0.05);两性间睡眠、卧息、运动和其他行为均存在显著差异（P＜0.05)。笼养东北虎两性行为的差异可能与其野外的行为习惯有关,而这些行为习惯又与其担当的性别角色有紧密联系。     

A Transposon in Comt Generates mRNA Variants and Causes Widespread Expression and Behavioral Differences among Mice

Background

Catechol-O-methyltransferase (COMT) is a key enzyme responsible for the degradation of dopamine and norepinephrine. COMT activity influences cognitive and emotional states in humans and aggression and drug responses in mice. This study identifies the key sequence variant that leads to differences in Comt mRNA and protein levels among mice, and that modulates synaptic function and pharmacological and behavioral traits.

Methodology/Principal Findings

We examined Comt expression in multiple tissues in over 100 diverse strains and several genetic crosses. Differences in expression map back to Comt and are generated by a 230 nt insertion of a B2 short interspersed element (B2 SINE) in the proximal 3′ UTR of Comt in C57BL/6J. This transposon introduces a premature polyadenylation signal and creates a short 3′ UTR isoform. The B2 SINE is shared by a subset of strains, including C57BL/6J, A/J, BALB/cByJ, and AKR/J, but is absent in others, including DBA/2J, FVB/NJ, SJL/J, and wild subspecies. The short isoform is associated with increased protein expression in prefrontal cortex and hippocampus relative to the longer ancestral isoform. The Comt variant causes downstream differences in the expression of genes involved in synaptic function, and also modulates phenotypes such as dopamine D1 and D2 receptor binding and pharmacological responses to haloperidol.

Conclusions/Significance

We have precisely defined the B2 SINE as the source of variation in Comt and demonstrated that a transposon in a 3′ UTR can alter mRNA isoform use and modulate behavior. The recent fixation of the variant in a subset of strains may have contributed to the rapid divergence of inbred strains.