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Objective: To assess the effect of microscopic and macroscopic contamination of embryo transfer (ET) catheters with blood or mucus on in vitro fertilization (IVF)–ET success rates. Design: Retrospective cohort study. Setting: Infertility practice in teaching community hospital. Patient(s): Four hundred seventy patients undergoing IVF-ET. Intervention(s): Controlled ovarian hyperstimulation and IVF-ET. Main Outcome Measure(s): Implantation rate (IR) and clinical pregnancy rate (CPR). Result(s): The IR and CPR of IVF-ETs were comparable regardless of the presence (26.59% and 48.78%, respectively) or absence (23.49% and 44.44%, respectively) of any type of contamination. Even when analyzing specific contamination categories (i.e., macroscopic blood, microscopic blood on the outer catheter, microscopic blood on the inner catheter, blood anywhere without mucus, mucus only, or blood and mucus combined), there was no statistical significance in IR (range: 21.17% to 26.69%) or CPR (range: 32.69% to 49.5%). Conclusion(s): In general, IR and CPR appear to be unaffected by ET catheter contamination, whether it is macroscopic or microscopic presence of blood or mucus. [Copyright &y& Elsevier]

The optimal developmental stage for cryopreserving embryos in IVF-ET remains controversial. Our study demonstrates that besides an improvement in postthaw survival rate for day-1 and blastocyst cryopreserved ET over day-3, all three groups attained statistically similar implantation, clinical pregnancy, multiple, twinning, and male gender rates. [Copyright &y& Elsevier]

The answer to the simple question of how plants make auxin has proven to be inordinately complex. Recent in planta studies in Arabidopsis have uncovered additional complexity in auxin biosynthesis. Two distinct pathways from tryptophan to the intermediate indoleacetaldoxime were identified. Genic, as well as functional redundancy, appear to be characteristic for auxin biosynthesis and plants might have evolved many different solutions for making and regulating auxin. [Copyright &y& Elsevier]

We have analyzed the claims made in two highly popular books, which promulgate the idea that trees possess a number of human characteristics for which there is no sound scientific evidence. A critical evaluation of the mother tree hypothesis also reveals that much of the data given in support of this concept is flawed and perhaps even non-existent. This concept is also incompatible with many well-known observations on the growth of forest trees. Moreover, there is no evidence from peer-reviewed published studies to support the claim that mature trees in forests communicate preferentially with offspring through a common mycelial network. It also remains unclear whether carbon compounds transmitted in the mycorrhizae actually enter the root tissue of the receiver tree. In any event, numerous studies indicate that the amounts of carbon transferred are physiologically insignificant. There are growing doubts about the true role of the common mycorrhizal networks (CMN or wood wide web) connecting the roots of trees in forests. We question the claims of a substantial carbon transfer from 'mother trees' to their offspring and nearby seedlings through the CMN. Recent reviews show that evidence for the 'mother tree concept' is inconclusive or absent. The origin of this concept seems to stem from a desire to humanize plant life but can lead to misunderstandings and false interpretations and may eventually harm rather than help the commendable cause of preserving forests. Two recent books serve as examples: The Hidden Life of Trees and Finding the Mother Tree. A recent article highlights the growing doubts about the true role of the common mycorrhizal networks [CMN or wood wide web (WWW)] connecting the roots of trees in forests. It questions the claim of a substantial carbon transfer from 'mother trees' to their offspring and nearby seedlings through the CMN. Recent reviews show that evidence for the 'mother tree concept' is inconclusive or absent. The origin of this concept seems to stem from a desire to humanize plant life but can lead to misunderstandings and false interpretations and may eventually harm rather than help the commendable cause of preserving forests. Two recent books serve as examples: The Hidden Life of Trees and Finding the Mother Tree. [ABSTRACT FROM AUTHOR]

Highlights: [•] We summarize the long and complex history of auxin biosynthesis in plants. [•] At least five pathways have been proposed, including four from tryptophan. [•] Tryptophan can be converted to auxin via a single intermediate, indole-3-pyruvic acid. [ABSTRACT FROM AUTHOR]

Drought stress is the most important stress factor for plants, being the main cause of agricultural crop loss in the world. Plants have developed complex mechanisms for preventing water loss and oxidative stress such as synthesis of abscisic acid (ABA) and non-enzymatic antioxidant compounds such as anthocyanins, which might help plants to cope with abiotic stress as antioxidants and for scavenging reactive oxygen species. A. chilensis (Mol.) is a pioneer species, colonizing and growing on stressed and disturbed environments. In this research, an integrated analysis of secondary metabolism in Aristotelia chilensis was done to relate ABA effects on anthocyanins biosynthesis, by comparing between young and fully-expanded leaves under drought stress. Plants were subjected to drought stress for 20 days, and physiological, biochemical, and molecular analyses were performed. The relative growth rate and plant water status were reduced in stressed plants, with young leaves significantly more affected than fully-expanded leaves beginning from the 5th day of drought stress. A. chilensis plants increased their ABA and total anthocyanin content and showed upregulation of gene expression when they were subjected to severe drought (day 20), with these effects being higher in fully-expanded leaves. Multivariate analysis indicated a significant positive correlation between transcript levels for NCED1 (9-cis-epoxycarotenoid dioxygenase) and UFGT (UDP glucose: flavonoid-3-O-glucosyltransferase) with ABA and total anthocyanin, respectively. Thus, this research provides a more comprehensive analysis of the mechanisms that allow plants to cope with drought stress. This is highlighted by the differences between young and fully-expanded leaves, showing different sensibility to stress due to their ability to synthesize anthocyanins. In addition, this ability to synthesize different and high amounts of anthocyanins could be related to higher NCED1 and MYB expression and ABA levels, enhancing drought stress tolerance. [ABSTRACT FROM AUTHOR]

Honey bees, Apis mellifera , collect antimicrobial plant resins from the environment and deposit them in their nests as propolis. This behavior is of practical concern to beekeepers since the presence of propolis in the hive has a variety of benefits, including the suppression of disease symptoms. To connect the benefits that bees derive from propolis with particular resinous plants, we determined the identity and botanical origin of propolis compounds active against bee pathogens using bioassay-guided fractionation against the bacterium Paenibacillus larvae , the causative agent of American foulbrood. Eleven dihydroflavonols were isolated from propolis collected in Fallon, NV, including pinobanksin-3-octanoate. This hitherto unknown derivative and five other 3-acyl-dihydroflavonols showed inhibitory activity against both P. larvae (IC 50 = 17–68 μM) and Ascosphaera apis (IC 50 = 8–23 μM), the fungal agent of chalkbrood. A structure-activity relationship between acyl group size and antimicrobial activity was found, with longer acyl groups increasing activity against P. larvae and shorter acyl groups increasing activity against A. apis . Finally, it was determined that the isolated 3-acyl-dihydroflavonols originated from Populus fremontii , and further analysis showed these compounds can also be found in other North American Populus spp. [ABSTRACT FROM AUTHOR]

Auxin is a key regulator of plant development and in Arabidopsis thaliana can be synthesized through multiple pathways; however, the contributions of various biosynthetic pathways to specific developmental processes are largely unknown. To trace the involvement of various biosynthetic routes to indole-3-acetic acid (IAA) under conditions that induce adventitious root formation in Arabidopsis hypocotyls, we treated seedlings with three different stable isotope-labeled precursors ([13C 6 ]anthranilate, [15N 1 ]indole, and [13C 3 ]serine) and monitored label incorporation into a number of proposed biosynthesis intermediates as well as IAA. We also employed inhibitors targeting tryptophan aminotransferases and flavin monooxygenases of the IPyA pathway, and treatment with these inhibitors differentially altered the labeling patterns from all three precursors into intermediate compounds and IAA. [13C 3 ]Serine was used to trace utilization of tryptophan (Trp) and downstream intermediates by monitoring 13C incorporation into Trp, indole-3-pyruvic acid (IPyA), and IAA; most 13C incorporation into IAA was eliminated with inhibitor treatments, suggesting Trp-dependent IAA biosynthesis through the IPyA pathway is a dominant contributor to the auxin pool in de-etiolating hypocotyls that can be effectively blocked using chemical inhibitors. Labeling treatment with both [13C 6 ]anthranilate and [15N 1 ]indole simultaneously resulted in higher label incorporation into IAA through [15N 1 ]indole than through [13C 6 ]anthranilate; however, this trend was reversed in the proposed precursors that were monitored, with the majority of isotope label originating from [13C 6 ]anthranilate. An even greater proportion of IAA became [15N 1 ]-labeled compared to [13C 6 ]-labeled in seedlings treated with IPyA pathway inhibitors, suggesting that, when the IPyA pathway is blocked, IAA biosynthesis from labeled indole may also come from an origin independent of the measured pool of Trp in these tissues. When the indole-3-pyruvate pathway in Arabidopsis thaliana hypocotyls is blocked with chemical inhibitors, indole-3-acetic acid biosynthesis from labeled indole may come from an origin independent of the measured pool of tryptophan in these tissues. [Display omitted] • A complex biosynthetic network is responsible for producing IAA. • Both Trp-dependent and Trp-independent pathways contribute to IAA levels in Arabidopsis. • More IAA can be produced independently of Trp when Trp-dependent biosynthesis is inhibited. • Multiple precursor labeling and LC-MS analysis offer insight into precursor utilization. • Specific chemical inhibitors provide powerful tools for investigating specific pathways. [ABSTRACT FROM AUTHOR]

Global environmental temperature changes threaten innumerable plant species. Although various signaling networks regulate plant responses to temperature fluctuations, the mechanisms unifying these diverse processes are largely unknown. Here, we demonstrate that an Arabidopsis monothiol glutaredoxin, AtGRXS17 (At4g04950), plays a critical role in redox homeostasis and hormone perception to mediate temperature-dependent postembryonic growth. AtGRXS17 expression was induced by elevated temperatures. Lines altered in AtGRXS17 expression were hypersensitive to elevated temperatures and phenocopied mutants altered in the perception of the phytohormone auxin. We show that auxin sensitivity and polar auxin transport were perturbed in these mutants, whereas auxin biosynthesis was not altered. In addition, atgrxs17 plants displayed phenotypes consistent with defects in proliferation and/or cell cycle control while accumulating higher levels of reactive oxygen species and cellular membrane damage under high temperature. Together, our findings provide a nexus between reactive oxygen species homeostasis, auxin signaling, and temperature responses. [ABSTRACT FROM AUTHOR]

Abstract: Indole-3-acetaldoxime (IAOx) is a branch point compound of tryptophan (Trp) metabolism in glucosinolate-producing species such as Arabidopsis, serving as a precursor to indole-glucosinolates (IGs), the defense compound camalexin, indole-3-acetonitrile (IAN) and indole-3-acetic acid (IAA). We synthesized [2H5] and [13C10 15N2]IAOx and [13C6], [2H5] and [2′,2′-2H2]IAN in order to quantify endogenous IAOx and IAN in Arabidopsis and tobacco, a non-IG producing species. We found that side chain-labeled [2′,2′-2H2]IAN overestimated the amount of IAN by 2-fold compared to when [2H5]IAN was used as internal standard, presumably due to protium–deuterium exchange within the internal standard during extraction of plant tissue. We also determined that [13C1]IAN underestimated the amount of IAN when the ratio of [13C1]IAN standard to endogenous IAN was greater than five to one, whereas either [2H5]IAN or [13C6]IAN showed a linear relationship with endogenous IAN over a broader range of concentrations. Transgenic tobacco vector control lines did not have detectable levels of IAOx or IAN (limit of detection∼100pg/gfr.wt), while lines expressing either the IAOx-producing CYP79B2 or CYP79B3 genes from Arabidopsis under CaMV 35S promoter control accumulated IAOx in the range of 1–9μg/gfr.wt. IAN levels in these lines ranged from 0.6 to 6.7μg/gfr.wt, and IAA levels were ∼9–14-fold above levels in control lines. An Arabidopsis line expressing the same CYP79B2 overexpression construct accumulated IAOx in two of three lines measured (∼200 and 400ng/gfr.wt) and accumulated IAN in all three lines. IAN is proposed to be a metabolite of IAOx or an enzymatic breakdown product of IGs induced upon tissue damage. Since tobacco does not produce detectable IGs, the tobacco data are consistent with IAN being a metabolite of IAOx. IAOx and IAN were also examined in the Arabidopsis activation tagged yucca mutant, and no accumulation of IAOx was found above the limits of detection but accumulation of IAN (3-fold above wt) occurred. The latter was surprising in light of recent reports that rule out IAOx and IAN as intermediates in YUCCA-mediated IAA synthesis. [Copyright &y& Elsevier]

Abstract: Indole-3-acetic acid is an indispensable hormone (auxin) in plants and an important metabolite in humans, animals, and microorganisms. Here we introduce its 5- and 6-(2-aminoethyl)-derivatives for use in the design of novel research tools, such as immobilized and carrier-linked forms of indole-3-acetic acid and its conjugates with biochemical tags or biocompatible molecular probes. The aliphatic nitrogens of 5- and 6-(2-aminoethyl)indole were acetylated and the products were converted to the corresponding 3-(N,N-dimethylamino)methyl derivatives (gramines). These were reacted with cyanide. Saponification of the resulting acetonitriles was accompanied by N-deprotection to yield 5- and 6-(2-aminoethyl)indole-3-acetic acids. The latter were chemically stable and could be linked, via their amino groups, and without prior protection of their carboxyl moieties, to bovine serum albumin and to biotin, including appropriate spacer modules. One of the protein conjugates was used to elicit the formation of monoclonal antibodies, which were evaluated using the biotin conjugates in an enzyme-linked immunosorbent assay employing streptavidin-coupled alkaline phosphatase, and thus shown to recognize predominantly the indole-3-acetic acid moiety. [Copyright &y& Elsevier]