Search

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2009.01.034 Byline: Kathleen A. Estes, Wendy Hanna-Rose Keywords: unc-6; fos-1; unc-40; Cell migration; zmp-1; lin-3; AJM-1; TAT-2 Abstract: Tubulogenesis and lumen formation are critical to the development of most organs. We study Caenorhabditis elegans vulval and uterine development to probe the complex mechanisms that mediate these events. Development of the vulva and the ventral uterus is coordinated by the inductive cell-signaling activity of a gonadal cell called the anchor cell (AC). We demonstrate that in addition to its function in specifying fate, the AC directly promotes dorsal vulval tubulogenesis. Two types of mutants with defective anchor cell behavior reveal that anchor cell invasion of the vulva is important for forming the toroidal shape of the dorsal vulval cell, vulF. In fos-1 mutants, where the AC cannot breakdown the basement membranes between the gonad and the vulva, and in mutants in unc-6 netrin or its receptor unc-40, which cause AC migration defects, the AC fails to invade the vulva and no lumen is formed in vulF. By examining GFP markers of dorsal vulval cell fate, we demonstrate that fate specification defects do not account for the aberrant vulF shape. We propose that the presence of the AC in the center of the developing vulF toroid is required for dorsal vulval lumen formation to complete vulval tubulogenesis. Author Affiliation: Department of Biochemistry and Molecular Biology, 104D Life Science Building, The Pennsylvania State University, University Park, PA 16802, USA Article History: Received 2 September 2008; Revised 6 January 2009; Accepted 23 January 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2007.05.020 Byline: Kathleen A. Estes, Rasika Kalamegham, Wendy Hanna-Rose Keywords: LRAT; Hrasls3; Morphogenesis; Organogenesis; Tubulogenesis; Palmitoyltransferase Abstract: Vulval morphogenesis in Caenorhabditis elegans generates a stack of toroidal cells enclosing a tubular lumen. Mutation of egl-26 is associated with malformation of vulF, the most dorsal toroid in the stack, resulting in a blocked lumen and an egg-laying defect. Here we present evidence that vulF retains the expected gene expression pattern, functions in signaling to the uterus and retains proper polarity when egl-26 is mutated, all suggesting that mutation of egl-26 specifically results in aberrant morphogenesis as opposed to abnormal fate specification. Recent computational analysis indicates that EGL-26, which was previously characterized as novel, belongs to the LRAT (lecithin retinol acyltransferase) subfamily of the NlpC/P60 superfamily of catalytic proteins. Via site-directed mutagenesis, we demonstrate a requirement of the putative catalytic residues for EGL-26 function in vivo. We also show that mutation of conserved serine 275 perturbs the apical membrane localization and the function of the EGL-26 protein. Additional mutagenesis of this residue suggests that EGL-26 attains its membrane localization via a mechanism distinct from that of LRAT. Author Affiliation: Department of Biochemistry and Molecular Biology, 104D Life Science Building, The Pennsylvania State University, University Park, PA 16802, USA Article History: Received 11 December 2006; Revised 26 April 2007; Accepted 18 May 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2006.02.010 Byline: Brian L. Nelms, Wendy Hanna-Rose Keywords: egl-13; Sox; him-8; C. elegans; Uterus; C2H2 zinc finger; Development; Egl; Cog Abstract: egl-13 encodes a Sox domain protein that is required for proper uterine seam cell development in Caenorhabditis elegans. We demonstrate that mutations of the C2H2 zinc fingers encoded by the him-8 (high incidence of males) gene partially suppress the egg-laying and connection-of-gonad morphology defects caused by incompletely penetrant alleles of egl-13. him-8 alleles have previously characterized recessive effects on recombination and segregation of the X chromosome during meiosis due to failure of X chromosome homolog pairing and subsequent synapsis. However, we show that him-8 alleles are semi-dominant suppressors of egl-13, and the semi-dominant effect is due to haplo-insufficiency of the him-8 locus. Thus, we conclude that the wild-type him-8 gene product acts antagonistically to EGL-13. Null alleles of egl-13 cannot be suppressed, suggesting that this antagonistic interaction most likely occurs either upstream of or in parallel with EGL-13. Moreover, we conclude that suppression of egl-13 is due to a meiosis-independent function of him-8 because suppression is observed in mutants that have severely reduced meiotic germ cell populations and suppression does not depend on the function of him-8 in the maternal germ line. We also show that the chromosomal context of egl-13 seems important in the him-8 suppression mechanism. Interactions between these genes can give insight into function of Sox family members, which are important in many aspects of metazoan development, and into functions of him-8 outside of meiosis. Author Affiliation: Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 201 Life Science Building, Room 104D, University Park, PA 16802, USA Article History: Received 31 October 2005; Revised 1 February 2006; Accepted 6 February 2006

In screens for Caenorhabditis elegans mutants defective in vulval morphogenesis, we isolated multiple mutants in which the uterus and the vulva fail to make a functional connection, resulting in an egg-laying defective phenotype. Two of these connection of gonad defective (Cog) mutants carry alleles of the egl-26 gene. We demonstrate that vulval lineages in egl-26 mutant animals are normal, but one vulval cell, vulF, adopts an abnormal morphology. This results in formation of an abnormally thick layer of vulval tissue at the apex of the vulva and a physical blockage of the exit to the vulva from the uterus, egl-26 was cloned and is predicted to encode a novel protein. Mosaic analysis indicates that egl-26 activity is required in the primary vulval lineage for vulF morphogenesis. Expression of a functional translational fusion of EGL-26 to GFP was observed within the primary vulval lineage only in vulE, which neighbors vulF. EGL-26 is localized at the apical edge of the vulE cell. It is thus possible that vulE acts to instruct morphological changes in the neighboring cell, vulF, in an interaction mediated by EGL-26. Key Words: Caenorhabditis elegans; vulva; morphogenesis; egl-26; organogenesis.

Abstract Current political rhetoric and some media commentaries suggest there is a yawning gap of understanding between policymakers and the reality of families living in poverty in 21st century Britain. A key reason identified for the disconnect between policymakers and families is the absence of the voices of the families in public discourse. In this paper accounts of the lived experiences of parents in poverty are examined in four UK qualitative studies published in the period 1998–2016. Their accounts highlight how problems of disadvantage can be cumulative, compounding and enduring. The struggle to provide the basics of family life and the role of supportive communities and relationships are explored. The impact on parents of financial stress, the sense of shame and stigma often experienced and the consequences for their physical and mental health are highlighted. Under the government's austerity policy, there is an increase in poverty even in working families, an increase in homelessness and considerable evidence emerging on the damaging consequences of food and fuel poverty on the health of children and parents. Listening to the lived realities of individual families provides a much greater understanding of family poverty and its causes and consequences, provides a corrective to the critical pejorative rhetoric and lays the foundation for the provision of appropriate government support. Highlights • A significant gap exists between the understanding of policymakers and the reality of families living in poverty in 21st Century Britain. • A key reason for this disconnect is the absence of the voices of the families in public discourse. • Accounts of the lived experiences of parents in poverty highlight how problems of disadvantage can be cumulative, compounding and enduring. • The impact on parents of financial stress, sense of shame and stigma as well as physical/mental health consequences are highlighted. • Under the government's austerity policy, there is an increase in poverty even in working families and an increase in homelessness. • Considerable evidence is emerging on the damaging consequences of food and fuel poverty on the health of children and parents. [ABSTRACT FROM AUTHOR]

Vulval cell-fate determination in Caenorhabditis elegans requires the action of numerous gene products, including components of the Ras/Raf/MAPK signaling cascade and the hox gene lin-39, sem-4 encodes a zinc finger protein with previously characterized roles in fate specification of sex myoblasts, coelomocytes, and multiple neuronal lineages in C. elegans (M. Basson and R. Horvitz, 1996, Genes Dev. 10, 1953-1965). By characterizing three new alleles of sem-4 that we identified in a screen for vulval-defective mutants, we determined that loss of sem-4 activity results in abnormal specification of the secondary vulval cell lineages. We analyzed sem-4 interactions with other genes involved in vulval differentiation and determined that sem-4 does not function directly in the Ras-mediated signal transduction pathway but acts in close association with and upstream of lin-39 to promote vulval cell fate. We demonstrate that sem-4 regulates lin-39 expression and propose that sem-4 is a regulator of lin-39 in the vulval cell-fate determination pathway that may act to link lin-39 to incoming signals. [C] 2000 Academic Press Key Words: Caenorhabditis elegans; lin-39; Ras signaling; sem-4; vulval development.

Zinc is necessary for successful gametogenesis in mammals; however the role of zinc in the gonad function of non-mammalian species has not been investigated. The genetic tractability, short generation time, and hermaphroditic reproduction of the nematode C. elegans offer distinct advantages for the study of impaired gametogenesis as a result of zinc deficiency. However the phenotypic reproductive effects arising from zinc restriction have not been established in this model. We therefore examined the effect of zinc deficiency on C. elegans reproduction by exposing worms to the zinc chelator N,N,N′,N′-tetrakis (2-pyridylmethyl)ethane-1,2-diamine (TPEN). Treatment began at the early larval stage and continued until reproductive senescence. TPEN treatment reduced the total number of progeny produced by C. elegans hermaphrodites compared with control subjects, with the largest difference in output observed 48 h after larval stage 4. At this time-point, zinc deficient worms displayed fewer embryos in the uterus and disorganized oocyte development when observed under DIC microscopy. DAPI staining revealed impaired oogenesis and chromosome dynamics with an expanded region of pachytene stage oocytes extending into the proximal arm of the gonad. This phenotype was not seen in control or zinc-rescue subjects. This study demonstrates that reproduction in C. elegans is sensitive to environmental perturbations in zinc, indicating that this is a good model for future studies in zinc-mediated subfertility. Aberrant oocyte development and disruption of the pachytene-diplotene transition indicate that oogenesis in particular is affected by zinc deficiency in this model. [ABSTRACT FROM AUTHOR]

Abstract: Mannose-binding C-type lectin (MBL) was purified by mannan-agarose affinity chromatography from blue catfish D+B (Ictalurus furcatus) and channel catfish NWAC 103 (Ictalurus punctatus) sera. The MBLs of blue catfish D+B and channel catfish NWAC 103 strains have not been purified by affinity chromatography, characterized and quantified. The affinity-purified and 2-ME reduced catfish MBLs showed one band of 66kDa for blue catfish D+B, and one band of 63kDa for channel catfish NWAC 103 by SDS-PAGE and Western blotting. Amino acid composition analysis (mol%) of the isolated catfish MBLs was done. The amount of methionine-S present in blue catfish D+B (0.78mol%) was 2.2-times greater when compared with channel catfish NWAC 103 (0.35mol%). The amount of proline present was 1.9-times greater in channel catfish NWAC 103 (8.0mol%) when compared with blue catfish D+B (4.3mol%). Tyrosine (2.5mol%) was present in blue catfish D+B but not detected in channel catfish NWAC 103. N-terminal amino acid sequencing by Edman degradation for the first 10 residues gave two amino acid sequences of XRQPESFRIV and XXEDGYGKMF that were identical for both blue catfish D+B and channel catfish NWAC 103. This could represent the presence of two different isoforms of catfish MBL. Blue catfish D+B had 21.3μg of MBL/ml of serum. Channel catfish NWAC 103 (#1 serum pool) had 15.1μg of MBL/ml of serum (obtained in late Fall season), and channel catfish NWAC 103 (#2 serum pool) had 10.2μg of MBL/ml of serum (obtained in Spring season). A seasonal variation in the channel catfish serum MBL was therefore seen. A standard curve for μg/ml of MBL in catfish serum was constructed with these data. The presence of MBL in blue catfish D+B and channel catfish NWAC 103 sera should be important in their innate immunity and resistance to Edwardsiella ictaluri and other microbial infections. This study describes the presence of MBL in these two Ictalurus species and evidence for a C-type lectin complement pathway of innate immunity. The channel catfish is used in aquaculture in the Southeast USA and is susceptible to bacterial infections acquired from its pond environment. [Copyright &y& Elsevier]

Abstract: In this study, we used an integrated approach to determine whether key biochemical, cellular, and physiological responses were related to growth impairment of cadmium (Cd)-exposed larval topsmelt (Atherinops affinis). Food intake (Artemia franciscana nauplii), oxygen consumption rates, apoptotic DNA fragmentation (TUNEL assay), and metallothionein (MT)-like protein levels, were separately measured in relation to growth of larval topsmelt aqueously exposed to sublethal doses of Cd for 14 days. Cadmium accumulation and concentrations of abundant metals were also evaluated in a subset of fish. Fish in the highest Cd treatments (50 and 100ppbCd) were smaller in final mean weight and length, and consumed fewer A. franciscana nauplii than control fish. Food intake was positively correlated with final weight of larval topsmelt in Cd and control treatments; food intake increased as final weight of the fish increased. Oxygen consumption rates were positively correlated with Cd concentration and mean oxygen consumption rates were inversely correlated with final mean weight of topsmelt; the smallest fish were found in the highest Cd treatment and were respiring at higher rates than control fish. Apoptotic DNA fragmentation was concentration-dependent and was associated with diminished growth. Apoptotic DNA fragmentation was elevated in the gill of fish exposed to 50ppbCd, and in the gut, gill, and liver of fish exposed to 100ppbCd. Metallothionein (MT)-like protein levels in fish from 100ppbCd treatments were significantly higher than those in other treatments. Oxygen consumption rates may have increased as a compensatory response to Cd exposure. However, it is likely that the energy produced was allocated to an increased metabolic demand due to apoptosis, MT synthesis, and changes in ion regulation. This diversion of energy expenditures could contribute to growth impairment of Cd-exposed fish. [Copyright &y& Elsevier]

NAD+ biosynthesis is an attractive and promising therapeutic target for influencing health span and obesity-related phenotypes as well as tumor growth. Full and effective use of this target for therapeutic benefit requires a complete understanding of NAD+ biosynthetic pathways. Here, we report a previously unrecognized role for a conserved phosphoribosyltransferase in NAD+ biosynthesis. Because a required quinolinic acid phosphoribosyltransferase (QPRTase) is not encoded in its genome, Caenorhabditis elegans are reported to lack a de novo NAD+ biosynthetic pathway. However, all the genes of the kynurenine pathway required for quinolinic acid (QA) production from tryptophan are present. Thus, we investigated the presence of de novo NAD+ biosynthesis in this organism. By combining isotope-tracing and genetic experiments, we have demonstrated the presence of an intact de novo biosynthesis pathway for NAD+ from tryptophan via QA, highlighting the functional conservation of this important biosynthetic activity. Supplementation with kynurenine pathway intermediates also boosted NAD+ levels and partially reversed NAD+-dependent phenotypes caused by mutation of pnc-1, which encodes a nicotinamidase required for NAD+ salvage biosynthesis, demonstrating contribution of de novo synthesis to NAD+ homeostasis. By investigating candidate phosphoribosyltransferase genes in the genome, we determined that the conserved uridine monophosphate phosphoribosyltransferase (UMPS), which acts in pyrimidine biosynthesis, is required for NAD+ biosynthesis in place of the missing QPRTase. We suggest that similar underground metabolic activity of UMPS may function in other organisms. This mechanism for NAD+ biosynthesis creates novel possibilities for manipulating NAD+ biosynthetic pathways, which is key for the future of therapeutics. [ABSTRACT FROM AUTHOR]

Temporal developmental progression is highly coordinated in Caenorhabditis elegans. However, loss of nicotinamidase PNC-1 activity slows reproductive development, uncoupling it from its typical progression relative to the soma. Using LC/MS we demonstrate that pnc-1 mutants do not salvage the nicotinamide released by NAD+ consumers to resynthesize NAD+, resulting in a reduction in global NAD+ bioavailability. We manipulate NAD+ levels to demonstrate that a minor deficit in NAD+ availability is incompatible with a normal pace of gonad development. The NAD+deficit compromises NAD+ consumer activity, but we surprisingly found no functional link between consumer activity and reproductive development. As a result we turned to a comparative metabolomics approach to identify the cause of the developmental phenotype. We reveal widespread metabolic perturbations, and using complementary pharmacological and genetic approaches, we demonstrate that a glycolytic block accounts for the slow pace of reproductive development. Interestingly, mitochondria are protected from both the deficiency in NAD+ biosynthesis and the effects of reduced glycolytic output. We suggest that compensatory metabolic processes that maintain mitochondrial activity in the absence of efficient glycolysis are incompatible with the requirements for reproductive development, which requires high levels of cell division. In addition to demonstrating metabolic requirements for reproductive development, this work also has implications for understanding the mechanisms behind therapeutic interventions that target NAD+ salvage biosynthesis for the purposes of inhibiting tumor growth. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to evaluate the efficacy of integrating a traditional sediment quality triad approach with selected sublethal chronic indicators in resident species in assessing sediment quality in four salt marshes in northern California, USA. These included the highly contaminated (Stege Marsh) and relatively clean (China Camp) marshes in San Francisco Bay and two reference marshes in Tomales Bay. Toxicity potential of contaminants and benthic macroinvertebrate survey showed significant differences between contaminated and reference marshes. Sublethal responses (e.g., apoptotic DNA fragmentation, lipid accumulation, and glycogen depletion) in livers of longjaw mudsucker (Gillichthys mirabilis) and embryo abnormality in lined shore crab (Pachygrapsus crassipes) also clearly distinguished contaminated and reference marshes, while other responses (e.g., cytochrome P450, metallothionein) did not. This study demonstrates that additional chronic sublethal responses in resident species under field exposure conditions can be readily combined with sediment quality triads for an expanded multiple lines of evidence approach. This confirmatory step may be warranted in environments like salt marshes in which natural variables may affect interpretation of toxicity test data. Qualitative and quantitative integration of the portfolio of responses in resident species and traditional approach can support a more comprehensive and informative sediment quality assessment in salt marshes and possibly other habitat types as well. [Copyright &y& Elsevier]

Abstract: A challenge in environmental management is to provide both methodology and a framework for assessing effects of pollutants in resident species and then applying the findings to management. The Pacific Estuarine Ecosystem Indicator Research (PEEIR) consortium advocates the development of an integrated portfolio of techniques using indicator species selected for various habitat types. We developed such a portfolio for California salt marsh ecosystems and evaluated the feasibility of our approach in management applications. PEEIR is employing a suite of biomarker responses in two indigenous species, the lined shore crab (Pachygrapsus crassipes) and the longjaw mudsucker (Gillichthys mirabilis). Detrimental effects such as apoptosis, endocrine disruption, and ovarian tumors have been observed in G. mirabilis at a site where toxicity test responses were relatively low. With P. crassipes, developmental abnormalities and several markers of decreased reproductive performance were quantified at the same site. Multivariate statistical techniques are used to examine the relationships between the responses and multiple contaminant and natural stressors. For the fish, findings are related to population-level parameters using dynamic energy budget (DEB) models. [Copyright &y& Elsevier]