Severe Developmental Abnormalities Research Articles

Marking RNA: m6A writers, readers, and functions in Arabidopsis.

N6-methyladenosine (m6A) emerges as an important modification in eukaryotic mRNAs. m6A has first been reported in 1974, and its functional significance in mammalian gene regulation and importance for proper development have been well established. An arsenal of writer, eraser, and reader proteins accomplish deposition, removal, and interpretation of the m6A mark, resulting in dynamic function. This led to the concept of an epitranscriptome, the compendium of RNA species with chemical modification of the nucleobases in the cell, in analogy to the epigenome. While m6A has long been known to also exist in plant mRNAs, proteins involved in m6A metabolism have only recently been detected by mutant analysis, homology search, and mRNA interactome capture in the reference plant Arabidopsis thaliana. Dysregulation of the m6A modification causes severe developmental abnormalities of leaves and roots and altered timing of reproductive development. Furthermore, m6A modification affects viral infection. Here, we discuss recent progress in identifying m6A sites transcriptome-wide, in identifying the molecular players involved in writing, removing, and reading the mark, and in assigning functions to this RNA modification in A. thaliana. We highlight similarities and differences to m6A modification in mammals and provide an outlook on important questions that remain to be addressed.

Generation of CDMLe012-A-1 cells: A pluripotent human embryonic stem cell model of Turner's syndrome

Monosomy of chromosome X is associated with high prenatal mortality of female embryos and severe developmental abnormalities of patients born with Turner's syndrome (45,XO). The CDMLe012-A-1 human embryonic stem cell (hESC) line, derived from a day six blastocyst with a normal 46,XX female karyotype spontaneously lost an X-chromosome during cell culture. This 45,XO karyotype was stably maintained for more than 55 passages. Since the CDMLe012-A-1 cells express pluripotent stem cell markers and differentiate into cells derived from the three germ layers, the cell line represents a stable, pluripotent stem cell model of Turner's syndrome.

Nucleocytoplasmic Shuttling of Geminivirus C4 Protein Mediated by Phosphorylation and Myristoylation Is Critical for Viral Pathogenicity

Many geminivirus C4 proteins induce severe developmental abnormalities in plants. We previously demonstrated that Tomato leaf curl Yunnan virus (TLCYnV) C4 induces plant developmental abnormalities at least partically by decreasing the accumulation of NbSKη, an ortholog of Arabidopsis BIN2 kinase involved in the brassinosteroid signaling pathway, in the nucleus through directing it to the plasma membrane. However, the molecular mechanism by which the membrane-associated C4 modifies the localization of NbSKη in the host cell remains unclear. Here, we show that TLCYnV C4 is a nucleocytoplasmic shuttle protein, and that C4 shuttling is accompanied by nuclear export of NbSKη. TLCYnV C4 is phosphorylated by NbSKη in the nucleus, which promotes myristoylation of the viral protein. Myristoylation of phosphorylated C4 favors its interaction with exportin-α (XPO I), which in turn facilitates nuclear export of the C4/NbSKη complex. Supporting this model, chemical inhibition of N-myristoyltransferases or exportin-α enhanced nuclear retention of C4, and mutations of the putative phosphorylation or myristoylation sites in C4 resulted in increased nuclear retention of C4 and thus decreased severity of C4-induced developmental abnormalities. The impact of C4 on development is also lessened when a nuclear localization signal or a nuclear export signal is added to its C-terminus, restricting it to a specific cellular niche and therefore impairing nucleocytoplasmic shuttling. Taken together, our results suggest that nucleocytoplasmic shuttling of TLCYnV C4, enabled by phosphorylation by NbSKη, myristoylation, and interaction with exportin-α, is critical for its function as a pathogenicity factor.

PpV, acting via the JNK pathway, represses apoptosis during normal development of Drosophila wing.

Apoptosis is one of the main fundamental biological processes required for development of multicellular organisms. Inappropriate regulation of apoptosis can lead to severe developmental abnormalities and diseases. Therefore, the control of apoptosis, not only for its activation but also for its inhibition, is critically important during development. In contrast to the extensive studies of apoptosis induction, its inhibitory mechanisms that are even more vital in certain populations of cells actually are very far from being well understood. Here we report an inhibitory role of protein phosphatase V (PpV), a serine/threonine protein phosphatase, in controlling the apoptosis during Drosophila wing development. We observed that inhibition of ppv by RNAi in wing imaginal discs induced ectopic cell death and caspase activation, thus, resulted in a defective adult wing. Moreover, knocking-down ppv triggered the activation of c-Jun N-terminal kinase (JNK) signal, an evolutionarily conserved intracellular signaling that has been implicated to modulate the apoptotic machinery in many biological and experimental systems. Disrupting the JNK signal transduction was adequate to suppress the ppv effects for wing development. Together, we provided the evidence to demonstrate that ppv is required for normal wing development in maintaining the silence of apoptotic signal possibly through JNK pathway.

Renal tubular dysgenesis and microcolon, a novel association. Report of three cases

Renal tubular dysgenesis (RTD) is a developmental abnormality of the nephron characterized by fetal anuria, oligohydramnios, and severe postnatal hypotension. Genetic forms have an autosomal recessive inheritance and are caused by mutations in genes encoding key components of the renin-angiotensin pathway. We report three patients from two unrelated families with RTD due to pathogenic variants of the angiotensin-converting enzyme (ACE) gene, in whom RTD was associated with microcolon. We also detail key variations of the renin-angiotensin system in one of these infants.The severe intestinal developmental abnormality culminating in microcolon and early terminal ileum perforation/necrotizing enterocolitis is a novel finding not previously associated with RTD, which points to a role of the renin-angiotensin system in gut development.

A Novel In Vivo Model to Study Impaired Tissue Regeneration Mediated by Cigarette Smoke

Cigarette smoke is associated with several pathologies including chronic respiratory diseases and cancer. In addition, exposure to cigarette smoke is correlated with impaired wound healing, where a significant decrease in the regenerative capacity of smokers is well documented and broadly considered a negative risk factor after trauma or surgery. So far, some in vitro and in vivo models have been described to study how exposure to cigarette smoke diminishes the regenerative potential in different organisms. However, although useful, many of these models are difficult and expensive to implement and do not allow high-throughput screening approaches. In order to establish a reliable and accessible model, we have evaluated the effects of cigarette smoke extract (CSE) on zebrafish development and regeneration. In this work, zebrafish embryos and larvae were exposed to low doses of aqueous CSE showing severe developmental abnormalities in a dose-dependent manner. Furthermore, when adult zebrafish were subjected to caudal fin amputation, we observed a significant decrease in the regenerative capacity of animals exposed to CSE. The effect was exacerbated in male and aged fish compared to female or young organisms. The establishment of a zebrafish model to assess the consequences of cigarette smoke and its effects on animal physiology could provide a new tool to study the underlying mechanisms involved in impaired tissue regeneration, and aid the development of novel approaches to treat complications associated with cigarette smoke toxicity.

Schinzel—Giedion Syndrome: First Czech Patients Confirmed by Molecular Genetic Analysis

AbstractSchinzel–Giedion syndrome (SGS) is a very rare genetic disorder characterized by distinctive facial features, severe developmental delay, seizures, and skeletal abnormalities. Whole exome sequencing, Sanger sequencing, and correlation with already published variants and cases allowed us to identify two different de novo mutations in the SETBP1 gene: NM_015559.2 (SETBP1): c.2601C > G (p.Ser867Arg) and c. 2608 G > A (p.Gly870Ser) in two Czech patients presenting with SGS features. Both mutations are within exon 4 of SETBP1, supporting the notion that exon 4 represents the mutation hotspot of the gene in patients with SGS.

Heterozygous missense variants of LMX1A lead to nonsyndromic hearing impairment and vestibular dysfunction

Unraveling the causes and pathomechanisms of progressive disorders is essential for the development of therapeutic strategies. Here, we identified heterozygous pathogenic missense variants of LMX1A in two families of Dutch origin with progressive nonsyndromic hearing impairment (HI), using whole exome sequencing. One variant, c.721G > C (p.Val241Leu), occurred de novo and is predicted to affect the homeodomain of LMX1A, which is essential for DNA binding. The second variant, c.290G > C (p.Cys97Ser), predicted to affect a zinc-binding residue of the second LIM domain that is involved in protein–protein interactions. Bi-allelic deleterious variants of Lmx1a are associated with a complex phenotype in mice, including deafness and vestibular defects, due to arrest of inner ear development. Although Lmx1a mouse mutants demonstrate neurological, skeletal, pigmentation and reproductive system abnormalities, no syndromic features were present in the participating subjects of either family. LMX1A has previously been suggested as a candidate gene for intellectual disability, but our data do not support this, as affected subjects displayed normal cognition. Large variability was observed in the age of onset (a)symmetry, severity and progression rate of HI. About half of the affected individuals displayed vestibular dysfunction and experienced symptoms thereof. The late-onset progressive phenotype and the absence of cochleovestibular malformations on computed tomography scans indicate that heterozygous defects of LMX1A do not result in severe developmental abnormalities in humans. We propose that a single LMX1A wild-type copy is sufficient for normal development but insufficient for maintenance of cochleovestibular function. Alternatively, minor cochleovestibular developmental abnormalities could eventually lead to the progressive phenotype seen in the families.

Enriched expression of the ciliopathy gene Ick in cell proliferating regions of adult mice

Cilia are essential for sensory and motile functions across species. In humans, ciliary dysfunction causes “ciliopathies”, which show severe developmental abnormalities in various tissues. Several missense mutations in intestinal cell kinase (ICK) gene lead to endocrine-cerebro-osteodysplasia syndrome or short rib-polydactyly syndrome, lethal recessive developmental ciliopathies. We and others previously reported that Ick-deficient mice exhibit neonatal lethality with developmental defects. Mechanistically, Ick regulates intraflagellar transport and cilia length at ciliary tips. Although Ick plays important roles during mammalian development, roles of Ick at the adult stage are poorly understood. In the current study, we investigated the Ick gene expression in adult mouse tissues. RT-PCR analysis showed that Ick is ubiquitously expressed, with enrichment in the retina, brain, lung, intestine, and reproductive system. In the adult brain, we found that Ick expression is enriched in the walls of the lateral ventricle, in the rostral migratory stream of the olfactory bulb, and in the subgranular zone of the hippocampal dentate gyrus by in situ hybridization analysis. We also observed that Ick staining pattern is similar to pachytene spermatocyte to spermatid markers in the mature testis and to an intestinal stem cell marker in the adult small intestine. These results suggest that Ick is expressed in proliferating regions in the adult mouse brain, testis, and intestine.

Arabidopsis TSO1 and MYB3R1 form a regulatory module to coordinate cell proliferation with differentiation in shoot and root

Fundamental to plant and animal development is the regulated balance between cell proliferation and differentiation, a process intimately tied to cell cycle regulation. In Arabidopsis, mutations in TSO1, whose animal homolog is LIN54, resulted in severe developmental abnormalities both in shoot and root, including shoot meristem fasciation and reduced root meristematic zone. The molecular mechanism that could explain the tso1 mutant phenotype is absent. Through a genetic screen, we identified 32 suppressors that map to the MYB3R1 gene, encoding a conserved cell cycle regulator. Further analysis indicates that TSO1 transcriptionally represses MYB3R1, and the ectopic MYB3R1 activity mediates the tso1 mutant phenotype. Since animal homologs of TSO1 and MYB3R1 are components of a cell cycle regulatory complex, the DREAM complex, we tested and showed that TSO1 and MYB3R1 coimmunoprecipitated in tobacco leaf cells. Our work reveals a conserved cell cycle regulatory module, consisting of TSO1 and MYB3R1, for proper plant development.

Assessment of squalene eligibility in bettering some maternal and fetal disorders instigated by gamma irradiation of rats at mid gestation

Purpose: Squalene is an eminent vital part of the synthesis of steroid hormones in the body as well as the first specific intermediate in cholesterol biosynthesis that plays an essential role in normal embryogenesis. The present work was designed to test the maternal and embryonic response to the modulating capacity of squalene (0.4 ml/kg/d), when supplemented to rats from days 1 to 18 of pregnancy, against the damaging consequences induced by maternal subjection to 3 Gy gamma irradiation on day 10 post-conception.Materials and methods: The experimental protocol comprised of four different pregnant groups, namely: (1) control, (2) squalene supplemented, (3) irradiated and (4) squalene supplemented + irradiated.Results: It has been detected that radiation has increased the maternal blood lactate dehydrogenase (as a marker of tissue injury), cholesterol, triglycerides, estradiol and progesterone and has also provoked the oxidative stress that has been demonstrated by the increased malondialdehyde (MDA) and the decreased glutathione (GSH) and superoxide dismutase (SOD). These maternal changes were associated with high embryonic lethality, growth retardation, severe developmental abnormalities and defective neural tube closure expressed by exencephaly. However, squalene treatment has significantly improved the radiation imposed maternal variations and reduced the embryonic mortality, although it has not been able to attenuate the embryonic neural tube defects.Conclusions: It has been presumed that the maternal mid-gestational irradiation (day 10) has affected the fetal nervous system development with concomitant maternal oxidative stress, hyperlipidemia, and increased progesterone and estradiol levels. Squalene uptake has improved the maternal variations and reduced the embryonic mortality while could not stop or improve the embryonic neural tube defects imposed by radiation at this exact radiation timing.

Arabidopsis plants exposed to dioxin result in a WRINKLED seed phenotype due to 20S proteasomal degradation of WRI1.

Dioxins are highly toxic persistent organic pollutants bioaccumulated by both plants and animals that cause severe developmental abnormalities in humans. We investigated the effects of dioxins on seed development in Arabidopsis. Plants were exposed to various concentrations of the most toxic congener of dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the effects on seed development were analysed in-depth at transcriptome, proteome and metabolome levels. Exposure to dioxin led to generalized effects on vegetative tissues plus a specific set of perturbations to seed development. Mature seeds from TCDD-treated plants had a characteristic 'wrinkled' phenotype, due to a two-thirds reduction in storage oil content. Transcriptional analysis of a panel of genes related to lipid and carbohydrate metabolism was consistent with the observed biochemical phenotypes. There were increases in WRI1 and LEC1 expression but decreases in ABI3 and FUS3 expression, which is puzzling in view of the low seed oil phenotype. This anomaly was explained by increased expression of 20S proteasome components that resulted in a substantial degradation of WRI1 protein, despite the up-regulation of the WRI1 gene. Our findings reveal novel effects of dioxins that lead to altered gene regulation patterns that profoundly affect seed development in Arabidopsis.

Copper induces expression and methylation changes of early development genes in Crassostrea gigas embryos

Copper contamination is widespread along coastal areas and exerts adverse effects on marine organisms such as mollusks. In the Pacific oyster, copper induces severe developmental abnormalities during early life stages; however, the underlying molecular mechanisms are largely unknown. This study aims to better understand whether the embryotoxic effects of copper in Crassostrea gigas could be mediated by alterations in gene expression, and the putative role of DNA methylation, which is known to contribute to gene regulation in early embryo development.For that purpose, oyster embryos were exposed to 4 nominal copper concentrations (0.1, 1, 10 and 20 μg L−1 Cu2+) during early development assays. Embryotoxicity was monitored through the oyster embryo-larval bioassay at the D-larva stage 24 h post fertilization (hpf) and genotoxicity at gastrulation 7 hpf. In parallel, the relative expression of 15 genes encoding putative homeotic, biomineralization and DNA methylation proteins was measured at three developmental stages (3 hpf morula stage, 7 hpf gastrula stage, 24 hpf D-larvae stage) using RT-qPCR. Global DNA content in methylcytosine and hydroxymethylcytosine were measured by HPLC and gene-specific DNA methylation levels were monitored using MeDIP-qPCR.A significant increase in larval abnormalities was observed from copper concentrations of 10 μg L−1, while significant genotoxic effects were detected at 1 μg L−1 and above. All the selected genes presented a stage-dependent expression pattern, which was impaired for some homeobox and DNA methylation genes (Notochord, HOXA1, HOX2, Lox5, DNMT3b and CXXC-1) after copper exposure. While global DNA methylation (5-methylcytosine) at gastrula stage didn’t show significant changes between experimental conditions, 5-hydroxymethylcytosine, its degradation product, decreased upon copper treatment. The DNA methylation of exons and the transcript levels were correlated in control samples for HOXA1 but such a correlation was diminished following copper exposure. The methylation level of some specific gene regions (HoxA1, Hox2, Engrailed2 and Notochord) displayed changes upon copper exposure. Such changes were gene and exon-specific and no obvious global trends could be identified. Our study suggests that the embryotoxic effects of copper in oysters could involve homeotic gene expression impairment possibly by changing DNA methylation levels.

Tomato leaf curl Yunnan virus-encoded C4 induces cell division through enhancing stability of Cyclin D 1.1 via impairing NbSKη -mediated phosphorylation in Nicotiana benthamiana.

The whitefly-transmitted geminiviruses induce severe developmental abnormalities in plants. Geminivirus-encoded C4 protein functions as one of viral symptom determinants that could induce abnormal cell division. However, the molecular mechanism by which C4 contributes to cell division induction remains unclear. Here we report that tomato leaf curl Yunnan virus (TLCYnV) C4 interacts with a glycogen synthase kinase 3 (GSK3)/SHAGGY-like kinase, designed NbSKη, in Nicotiana benthamiana. Pro32, Asn34 and Thr35 of TLCYnV C4 are critical for its interaction with NbSKη and required for C4-induced typical symptoms. Interestingly, TLCYnV C4 directs NbSKη to the membrane and reduces the nuclear-accumulation of NbSKη. The relocalization of NbSKη impairs phosphorylation dependent degradation on its substrate-Cyclin D1.1 (NbCycD1;1), thereby increasing the accumulation level of NbCycD1;1 and inducing the cell division. Moreover, NbSKη-RNAi, 35S::NbCycD1;1 transgenic N. benthamiana plants have the similar phenotype as 35S::C4 transgenic N. benthamiana plants on callus-like tissue formation resulted from abnormal cell division induction. Thus, this study provides new insights into mechanism of how a viral protein hijacks NbSKη to induce abnormal cell division in plants.

Iniencephaly.

Iniencephaly is a severe developmental abnormality of the craniovertebral junction in which the head is retroflexed dramatically. Anatomic studies have identified striking changes in the vertebrae and skull: marked lordosis of the cervical vertebrae, duplicated cervical vertebrae, irregularly fused cervical vertebrae, a widened foramen magnum and a small posterior fossa. The affected infant appears to have no neck, as the skin of the face is continuous with the chest and the skin of the posterior scalp is continuous with the skin of the back. Iniencephaly is considered a rare neural tube defect. The frequency has been higher in geographic areas in which the rates of occurrence of anencephaly and myelomeningocele were high. Most affected fetuses are either stillborn or die soon after birth. However, one affected individual is an adult with normal intelligence. A malformations surveillance program can identify an unselected group of infants with iniencephaly. This approach can determine the prevalence rate, the frequency of associated malformations, and the occurrence of close relatives with other neural tube defects. Over 41 years, the surveillance of 289,365 births identified eight fetuses and newborn infants with iniencephaly. Five of the eight had either an additional encephalocele or a thoracic myelomeningocele. Two of the eight affected infants had a sibling or a cousin with anencephaly. These findings suggest a relationship between the occurrence of iniencephaly and the most common neural tube defects, anencephaly and myelomeningocele. Recent experience confirms that this complex neural tube defect is not always lethal. Birth Defects Research 110:128-133, 2018. © 2018 Wiley Periodicals, Inc.

Safety and efficacy of telbivudine in late pregnancy to prevent mother-to-child transmission of hepatitis B virus: A multicenter prospective cohort study.

Infection of hepatitis B virus (HBV) occurs in ~10% of infants of HBV-infected mothers with positive hepatitis B e antigen (HBeAg) after immunoprophylaxis. We aimed to evaluate the safety and efficacy of telbivudine used during late pregnancy for preventing mother-to-child transmission of HBV. We conducted a multicenter prospective cohort study in 5 hospitals from 2012 to 2014, which enrolled HBV-infected singleton pregnant women with positive HBeAg. By their choice, women were divided into therapy (telbivudine 600mg/day, from gestation 28-32weeks to 3-4weeks postpartum) and control (no antiviral agent) groups. Infants received passive-active immunoprophylaxis and follow-up at the age of 7-14months. Totally, 328 pregnant women were included: 149 in the telbivudine group and 179 in the control group. Baseline HBV DNA levels were similar in the 2 groups (7.43 vs 7.37 log10 IU/mL, P=.711). At delivery, HBV DNA levels in the telbivudine and control groups were 3.80 and 7.26 log10 IU/mL, respectively (P<.0001). Of the infants, 128 (85.9%) in the telbivudine group and 156 (87.2%) in the control group were followed up. No infant in the telbivudine group had chronic infection, while 2 (1.28%) infants in the control group did (P=.503). Three (2.34%) infants in the telbivudine group, but none in the control group, had severe congenital or developmental abnormalities (P=.090). The data indicate that telbivudine may block perinatal HBV transmission. However, larger studies are required to clarify whether anti-HBV therapy in pregnancy is associated with severe adverse effects in the foetuses and infants.

Chronic intestinal pseudo-obstruction in a child with Treacher Collins syndrome

Treacher Collins syndrome (TCS) mainly presents with severe craniofacial developmental abnormalities characterized by a combination of bilateral downward-slanting palpebral fissures, colobomas of the lower eyelids, hypoplasia of the facial bones, cleft palate, malformation of the external ears, atresia of the external auditory canals, and bilateral conductive hearing loss. It is due to mutations in Treacher Collins syndrome 1 (TCOF1) (5q32-q33.1) and Polymerase RNA 1 polypeptides D and C (POLR1D [13q12.2], and POLR1C [6p21.1]) genes, which are responsible for increased neuroepithelial apoptosis during embryogenesis resulting in the lack of neural crest cells involved in facial bone and cartilage formation. Altered function of the upper digestive tract has been reported, whereas severe dysmotility disorders have never been reported. We describe here the first case of TCS associated with histologically proven chronic intestinal pseudo-obstruction (CIPO) in humans. Case presentatios A 12-year-old boy with TCS due to TCOF1 gene deletion experienced nutritional difficulties and digestive intolerance from birth. CIPO was suspected during childhood because of severe intestinal dysmotility leading to enteral-jejunal nutrition intolerance and dependence on total parenteral nutrition. Diagnosis of CIPO with nervous abnormalities was histologically confirmed on a surgical rectal biopsy that showed enlarged ganglionic myenteric plexus. At the age of 9 years, an isolated colonic stenosis without dilatation responsible for severe abdominal pain and altered quality of life led to digestive derivation contributing to rapid disappearance of chronic abdominal pain. At the age of 12 years, the patient was still dependent on total home parenteral nutrition 7 days a week to maintain regular growth velocity. Recently, mice studies have pointed out the role played by TCOF1 in ganglionic cell migration in the foregut, suggesting that the synergistic haploinsufficiency of Tcof1 and Pax3, a transcription factor regulating the RET gene involved in disorders of neural crest cell development, probably results in colonic aganglionosis and may explain the association described here between TCS and CIPO. This case may correspond to this possible mechanism in humans. These findings and our clinical report suggest that CIPO may be assessed as unusual digestive manifestations in TCS with TCOF1 deletion.

Brain calcifications and PCDH12 variants.

Objective:To assess the potential connection between PCDH12 and brain calcifications in a patient carrying a homozygous nonsense variant in PCDH12 and in adult patients with brain calcifications.Methods:We performed a CT scan in 1 child with a homozygous PCDH12 nonsense variant. We screened DNA samples from 53 patients with primary familial brain calcification (PFBC) and 26 patients with brain calcification of unknown cause (BCUC).Results:We identified brain calcifications in subcortical and perithalamic regions in the patient with a homozygous PCDH12 nonsense variant. The calcification pattern was different from what has been observed in PFBC and more similar to what is described in in utero infections. In patients with PFBC or BCUC, we found no protein-truncating variant and 3 rare (minor allele frequency <0.001) PCDH12 predicted damaging missense heterozygous variants in 3 unrelated patients, albeit with no segregation data available.Conclusions:Brain calcifications should be added to the phenotypic spectrum associated with PCDH12 biallelic loss of function, in the context of severe cerebral developmental abnormalities. A putative role for PCDH12 variants remains to be determined in PFBC.

Yellow crazy ants (Anoplolepis gracilipes) reduce numbers and impede development of a burrow-nesting seabird

Yellow crazy ants (Anoplolepis gracilipes) are a significant threat to biodiversity due to a rapidly expanding range and the potential to disrupt ecosystem interactions at multiple trophic levels. Extirpation of ground-nesting seabirds subsequent to yellow crazy ant invasion has been reported anecdotally. Yellow crazy ant control is difficult and resulting positive effects on nesting seabirds is undocumented. We report the effects of ant invasion and subsequent control on burrow-nesting seabirds following the invasion of more than half of a 1.25-ha wedge-tailed shearwater (Ardenna pacifica) colony located on eastern O‘ahu. The number of active seabird burrows in invaded areas dropped from 125 in 2006 to 6 in 2010, with no corresponding decline in active burrows in adjacent, uninvaded areas. Ant control efforts in 2011 reduced ant densities by more than 97% and resulted in a substantial increase in active burrows (43 in 2011). In invaded areas, burrows appeared to be abandoned by adults prior to egg-laying. Chicks surviving in invaded areas exhibited mild to severe developmental abnormalities, and overall had shorter culmens, tarsi and wingchords, smaller eye diameters, and lower weights than chicks outside invaded areas. We conclude that yellow crazy ants constitute a significant, and likely underestimated, risk to ground-nesting seabirds. Loss of seabird nesting colonies can have significant effects on nutrient inputs, and can bring about shifts in plant communities and faunal composition. Range expansion of yellow crazy ants is expected and ant/seabird interactions are likely to increase.

Human Zika and West Nile virus neurological infections: What is the difference?

The recent epidemic of West Nile Virus (WNV) infection in the United States was associated with severe neurological disease in immunocompromised hosts, while the emergence of Zika virus infection in the Americas has been notable for an association with increased microcephaly in the fetuses of infected mothers. Rare autopsies of WNV infected humans have shown multiple organ involvement with a clear neurotropism. We have recently had the opportunity to examine the distribution of Zika virus in autopsies of newborns from infected pregnancies. While both viruses infect multiple organs, Zika appears to cause neurological disease in the fetus through two different mechanisms. Infection during the first trimester showed the potential to infect neural progenitor cells causing severe developmental abnormalities, while infection later in gestation was associated with meningeal infection and destructive ischemic lesions of the brain. Both viruses infect kidney tubules but Zika shares a prominent hepatotropism characteristic of other flaviviruses (e.g., Dengue). Limited transplacental Zika infection would be consistent with restriction to primary maternal infections with high viremia. In the absence of a vaccine, restriction of travel by immunosuppressed and pregnant non-immune individuals to endemic regions seems prudent.