Microarray Analysis of Tomato’s Early and Late Wound Response Reveals New Regulatory Targets for Leucine Aminopeptidase A

Wounding due to mechanical injury or insect feeding causes a wide array of damage to plant cells including cell disruption, desiccation, metabolite oxidation, and disruption of primary metabolism. In response, plants regulate a variety of genes and metabolic pathways to cope with injury. Tomato (Solanum lycopersicum) is a model for wound signaling but few studies have examined the comprehensive gene expression profiles in response to injury. A cross-species microarray approach using the TIGR potato 10-K cDNA array was analyzed for large-scale temporal (early and late) and spatial (locally and systemically) responses to mechanical wounding in tomato leaves. These analyses demonstrated that tomato regulates many primary and secondary metabolic pathways and this regulation is dependent on both timing and location. To determine if LAP-A, a known modulator of wound signaling, influences gene expression beyond the core of late wound-response genes, changes in RNAs from healthy and wounded Leucine aminopeptidase A-silenced (LapA-SI) and wild-type (WT) leaves were examined. While most of the changes in gene expression after wounding in LapA-SI leaves were similar to WT, overall responses were delayed in the LapA-SI leaves. Moreover, two pathogenesis-related 1 (PR-1c and PR-1a2) and two dehydrin (TAS14 and Dhn3) genes were negatively regulated by LAP-A. Collectively, this study has shown that tomato wound responses are complex and that LAP-A’s role in modulation of wound responses extends beyond the well described late-wound gene core.     

Effects of Texture Component Orientation on Orientation Flow Visibility for 3-D Shape Perception

In images of textured 3-D surfaces, orientation flows created by the texture components parallel to the surface slant play a critical role in conveying the surface slant and shape. This study examines the visibility of these orientation flows in complex patterns. Specifically, we examine the effect of orientation of neighboring texture components on orientation flow visibility. Complex plaids consisting of gratings equally spaced in orientation were mapped onto planar and curved surfaces. The visibility of the component that creates the orientation flows was quantified by measuring its contrast threshold (CT) while varying the combination of neighboring components present in the pattern. CTs were consistently lowest only when components closest in orientation to that of the orientation flows were subtracted from the pattern. This finding suggests that a previously reported frequency-selective cross-orientation suppression mechanism involved with the perception of 3-D shape from texture is affected by proximity in orientation of concurrent texture components.     

Locomotor Performance Varies With Adult Phenotype in Ornamented/Non‐Ornamented Wolf Spiders

Locomotor performance constitutes a major component of whole‐animal performance and is involved in several fitness‐related behaviors. Locomotor capabilities may also correspond positively or negatively to sexually selected traits (e.g., male ornamentation and/or courtship displays). Negative correlations are predicted if secondary sexual traits take the form of morphological modifications that impose physical or energetic limitations. We tested this cost of secondary sexual traits by comparing locomotor performance in male Schizocosa wolf spiders that exhibit two distinct phenotypes. These phenotypes vary in the presence/absence of a morphological feature assumed to function as sexual ornamentation—foreleg brushes. Given the conspicuously large brushes of hair on the brush‐legged phenotype, we expected these males to suffer in locomotor performance. We tested this cost by comparing locomotor performance among male phenotypes (brush‐legged and non‐ornamented) and females at immature and adult life stages. We did not find strong support for costs of brushes on locomotion. First, brush‐legged males showed similar average speeds and endurance as both non‐ornamented males and females. Second, while brush‐legged males were slower at maximum speeds than non‐ornamented males as matures (but not as immatures), they were no slower than mature females. Further, we found no variation in endurance among phenotypes or life stages. Finally, brush size did not correspond to speed. Patterns of morphological variation in traits other than ornamentation may explain these patterns: when morphological variation in leg lengths was accounted for, differences in maximum speed among groups disappeared. We suggest that the faster speeds achieved by non‐ornamented males arise as a by‐product of selection on morphology and musculature potentially necessary for vigorous courtship.     

Temperature shock during development fails to increase the fluctuating asymmetry of a sexual trait in stalk-eyed flies.

The fluctuating asymmetry (FA) of bilateral traits is claimed to be a general indicator of environmental stress. Exaggerated sexual ornaments are thought to show elevated levels of FA and a greater response to stress than other traits. Previous work with stalk-eyed flies (Cyrtodiopsis dalmanni) has shown that the FA of the sexual trait (male eye stalks), wing length and wing width were unaffected by a continually applied food stress. Here we tested whether a transient stress (24-h heat shock at 31 degrees C during development) affected the FA of these traits. A second experiment tested the combined stresses of transient heat shock at 31 degrees C with continuous exposure to desiccation. In each experiment, temperature shock reduced the trait size, confirming that the treatments were stressful. However, stress had no effect on the FA of individual traits or the FA summed across all traits. Exposure to the combined stresses significantly elevated mortality and reduced trait size compared to the single-stress regime. However, FA did not differ significantly between flies from the two experiments. We found no evidence that FA in sexual and non-sexual traits reflects transient stress during the development of C. dalmanni.     

Classical biological control of Cirsium arvense: Lessons from the past

Cirsium arvense (L.) Scop. is a perennial herb indigenous to Eurasia that is now present throughout temperate regions of the world where it is considered one of the worst weeds of pastoral and agricultural systems. Classical biological control has been attempted in both North America (NA) and New Zealand (NZ). However, nearly 50 years after the first agent releases there are no indications of successful control. We review the status of the five agents deliberately released for control of C. arvense in NA and NZ, plus the species unintentionally introduced, and the occurrence of insects native to NA on C. arvense. We retrospectively evaluate C. arvense as a target weed, critique the agents selected for release, and contrast the different situations in NA and NZ. In retrospect, we see justification for the agents released in NA, but it is evident that these agents would not meet the more stringent host specificity requirements necessary to be released today. The failure of the program in NA is attributed to compromised safety, and lack of impact. Non-target impacts by one of the released agents, Rhinocyllus conicus, have raised safety concerns for native thistle plants. The other released agents either failed to establish, or if established, had no impact on the weed. In contrast, the situation in NZ is quite different because there are no related native thistles (Cardueae), and thus little chance of non-target impacts. Thus far, failure in NZ is attributed to lack of effectiveness due to non-establishment, or no impact, of released agents. In the past, the same agents that were released in NA were subsequently released in NZ, without considering whether or not these were the best choices. Thus, the past failure in NZ might be due to the previous lack of a NZ-specific approach to biocontrol of thistles in general and C. arvense in particular. A new approach taking into consideration the absence of native Cardueae has resulted in the release of agents more likely to be effective, and has potentially set NZ on track towards successful biological control of C. arvense, and other thistles.     

Breakdown of plant cell biomass by filamentous fungi

Three species of filamentous fungi, Botrytis cinerea, Sporotrichum thermophile and Trichoderma viride, have been selected to assess the potential of utilizing filamentous fungi to degrade plant cell biomass produced by mass cell culture techniques. All three fungal species grew comparatively well on plant cell biomass with no requirement for supplementary nutrients. Of the three species assessed B. cinerea demonstrated the most growth. This species also produced the greatest yield of d-glucose. However, when culture conditions were modified, yields of d-glucose were markedly reduced indicating that the combination of species and culture conditions must be thoroughly investigated to ensure maximum product yield. The growth of filamentous fungi on plant cells also markedly affected the nature of the resulting fungal-plant cell residue, increasing the levels of soluble carbohydrates and essential amino acids with the largest increase in these materials being promoted by B. cinerea.     

Practical Synthesis of Cytidine-5-Carboxamide-Modified Nucleotide Reagents

Chemically-modified derivatives of cytidine, bearing a 5-(N-substituted-carboxamide) functional group, are new reagents for use in aptamer discovery via the SELEX process (Systematic Evolution of Ligands by EXponential enrichment). Herein, we disclose a practical synthesis of 5-(N-benzylcarboxamide)-2′-deoxycytidine, and the corresponding 5-(N-1-naphthylmethylcarboxamide)- and 5-(N-3-phenylpropylcarboxamide)-2′-deoxycytidine analogs, as both the suitably-protected 3′-O-cyanoethylphosphoramidite reagents (CEP; gram scale) and the 5′-O-triphosphate reagents (TPP; milligram-scale). The key step in the syntheses is a mild, palladium(0)-catalyzed carboxyamidation of an unprotected 5-iodo-cytidine. Use of the CEP reagents for solid-phase oligonucleotide synthesis was demonstrated and incorporation of the TPP reagents by KOD polymerase in a primer extension assay confirmed the utility of these reagents for SELEX. Finally, the carboxyamidation reaction was also used to prepare the nuclease-resistant sugar-variants: 5-(N-benzylcarboxamide)-2′-O-methyl-cytidine and 5-(N-3-phenylpropylcarboxamide)-2′-deoxy-2′-fluoro-cytidine.     

Seasonal Variation In The Infestation Of Blackbirds By Fleas

The demand for feathers as a nest-building material was investigated by placing feather patches in woodland and garden sites between January and June 1993 and March and April 1994. The first of 18 species to breed in the area which use feathers in their nests was the Long-tailed Tit. The feather requirements of this species are known to far exceed that of the other species. Long-tailed Tits were shown to forage actively for feathers up to 115 m from the nest but possibly not as far as 200 m.

Patches generally remained untouched during the 24-h exposure but when detected were typically heavily exploited. Complete disappearance of feather patches occurred sporadically right to the end of the study.

The woodland contained only a low standing crop of moulted feathers and it is concluded that natural feather patches resulting from kills are important for birds who need this nest material. It is suggested that Long-tailed Tits may be attempting to avoid competition for feathers by nesting early.     

Genetic epidemiology of cardiometabolic risk factors and their clustering patterns in Mexican American children and adolescents: the SAFARI Study

Pediatric metabolic syndrome (MS) and its cardiometabolic components (MSCs) have become increasingly prevalent, yet little is known about the genetics underlying MS risk in children. We examined the prevalence and genetics of MS-related traits among 670 non-diabetic Mexican American (MA) children and adolescents, aged 6–17 years (49 % female), who were participants in the San Antonio Family Assessment of Metabolic Risk Indicators in Youth study. These children are offspring or biological relatives of adult participants from three well-established Mexican American family studies in San Antonio, TX, at increased risk of type 2 diabetes. MS was defined as ≥3 abnormalities among 6 MSC measures: waist circumference, systolic and/or diastolic blood pressure, fasting insulin, triglycerides, HDL-cholesterol, and fasting and/or 2-h OGTT glucose. Genetic analyses of MS, number of MSCs (MSC-N), MS factors, and bivariate MS traits were performed. Overweight/obesity (53 %), pre-diabetes (13 %), acanthosis nigricans (33 %), and MS (19 %) were strikingly prevalent, as were MS components, including abdominal adiposity (32 %) and low HDL-cholesterol (32 %). Factor analysis of MS traits yielded three constructs: adipo-insulin-lipid, blood pressure, and glucose factors, and their factor scores were highly heritable. MS itself exhibited 68 % heritability. MSC-N showed strong positive genetic correlations with obesity, insulin resistance, inflammation, and acanthosis nigricans, and negative genetic correlation with physical fitness. MS trait pairs exhibited strong genetic and/or environmental correlations. These findings highlight the complex genetic architecture of MS/MSCs in MA children, and underscore the need for early screening and intervention to prevent chronic sequelae in this vulnerable pediatric population.