Tropical Diseases in Okinawa: Overview and Emerging Infectious Diseases.

Okinawa prefecture is at risk for emerging infectious diseases due to its subtropical climate and its location within the Indo-Pacific region. Understanding the existing vectors and infectious agents contextualizes current threats, guides treatment, and informs prevention, and may be of unique concern in the setting of complex emergencies.

The complete dorsal structure is formed from only the blastocoel roof of Xenopus blastula: insight into the gastrulation movement evolutionarily conserved among chordates.

Gastrulation is a critical event whose molecular mechanisms are thought to be conserved among vertebrates. However, the morphological movement during gastrulation appears to be divergent across species, making it difficult to discuss the evolution of the process. Previously, we proposed a novel amphibian gastrulation model, the "subduction and zippering (S&Z) model". In this model, the organizer and the prospective neuroectoderm are originally localized in the blastula's blastocoel roof, and these embryonic regions move downward to make physical contact of their inner surfaces with each other at the dorsal marginal zone. The developmental stage when contact between the head organizer and the anterior-most neuroectoderm is established is called "anterior contact establishment (ACE)." After ACE, the A-P body axis elongates posteriorly. According to this model, the body axis is derived from limited regions of the dorsal marginal zone at ACE. To investigate this possibility, we conducted stepwise tissue deletions using Xenopus laevis embryos and revealed that the dorsal one-third of the marginal zone had the ability to form the complete dorsal structure by itself. Furthermore, a blastocoel roof explant of the blastula, which should contain the organizer and the prospective neuroectoderm in the S&Z model, autonomously underwent gastrulation and formed the complete dorsal structure. Collectively, these results are consistent with the S&Z gastrulation model and identify the embryonic region sufficient for construction of the complete dorsal structure. Finally, by comparing amphibian gastrulation to gastrulation of protochordates and amniotes, we discuss the gastrulation movement evolutionarily conserved among chordates.

The potential of a polyglycolic acid sheet for preventing intrathoracic sleeve migration.

INTRODUCTION: Postoperative gastroesophageal reflux disease (GERD) can be a consequence of laparoscopic sleeve gastrectomy (LSG). Intrathoracic sleeve migration (ITSM) is a factor contributing to its development. This study aimed to investigate whether the occurrence of ITSM can be prevented by applying a polyglycolic acid (PGA) sheet around the His angle. MATERIAL AND METHODS: In this retrospective analysis, 46 consecutive patients who underwent LSG were divided into two groups: Group A - our standard LSG in the first half (n = 23) and Group B - our standard LSG with PGA sheet covering the angle of His in the second half (n = 23). We compared the two groups for one-year postoperative GERD and the incidence of ITSM. RESULTS: No significant differences were found between the two groups in terms of patient background, operation time, and one-year postoperative total body weight loss, and no adverse effects related to the PGA sheet were observed. Group B had a significantly lower incidence of ITSM than Group A, and the rate of acid-reducing medicine usage was less pronounced in Group B during follow-up (p < .05). CONCLUSION: This study suggests that applying a PGA sheet can be safe and effective in reducing postoperative ITSM and preventing exacerbations of postoperative GERD.

Three SARS-CoV-2 PCR-negative cases of COVID-19 diagnosed using isothermal amplification methods.

Coronavirus disease (COVID-19) is a viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 can be detected by polymerase chain reaction (PCR) and isothermal nucleic acid amplification tests, including loop-mediated isothermal amplification (LAMP) and nicking endonuclease amplification reaction (NEAR) tests. Although PCR is the most sensitive and specific method and is generally considered to be the gold standard, it is time-consuming and costly. Isothermal nucleic acid amplification tests have lower sensitivity and specificity than PCR, but are less time-consuming and costly. We encountered three cases of SARS-CoV-2 infection in which the isothermal amplification test was positive but the PCR test was negative on the day of admission; however, the PCR test was positive the next day. These cases showed that some COVID-19 patients can test negative by PCR but positive using isothermal nucleic acid amplification methods. As PCR tests have the possibility of false-negative results, tests that use isothermal amplification methods which can be performed in a shorter time and at a lower cost than PCR tests, may be able to diagnose patients who have false negative PCR results.

A case report of breakthrough infection with the SARS-CoV-2 delta variant and household transmission: Role of vaccination, anti-spike IgG and neutralizing activity.

There have been several reports of breakthrough infections, which are defined as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among individuals who had received at least two doses of vaccine at least 14 days before the onset of infection, but data on the antibody titers, including SARS-CoV-2 neutralizing antibody activity, and the clinical course of individuals with breakthrough infections are limited. We encountered a case of breakthrough infection with the SARS-CoV-2 delta variant in a 31-year-old female healthcare worker (the index case, Case 1) and a secondary case (Case 2) in her unvaccinated 33-year-old husband. We studied the role of the anti-spike immunoglobulin G (IgG) and neutralizing antibody activity in the two case patients. Case 1 had high anti-spike IgG detected on day 3 of the illness, with low neutralizing antibody activity. The neutralizing antibody activity started to increase on day 5 of the illness. In Case 2 both the anti-spike IgG and the neutralizing antibody activity remained low from days 4-11 of illness, and the anti-spike IgG gradually increased from day 9. In Case 1, the fever broke within 4 days of onset, coinciding with the rise in neutralizing antibodies, whereas the fever took 7 days to resolve in Case 2. SARS-CoV-2 infection can occur even in vaccinated individuals, but vaccination may contribute to milder clinical symptoms because neutralizing antibodies are induced earlier in vaccinated individuals than in unvaccinated individuals.

Nationwide cross-sectional study of antimicrobial stewardship and antifungal stewardship programs in inpatient settings in Japan.

BACKGROUND: To prevent antimicrobial resistance, both antimicrobial stewardship (AMS) and antifungal stewardship (AFS) in inpatient settings are needed in small/middle-sized hospitals as well as large hospitals. METHODS: We conducted the web-based, self-administered, nationwide cross-sectional study regarding AMS and AFS in inpatient settings in Japan, targeting hospitals that participated in a hospital epidemiology workshop conducted in July 2018. The questionnaire was composed of intervention protocols for use of broad-spectrum antimicrobials and antifungals within 7 or 28 d of beginning usage. These broad-spectrum antimicrobial and antifungal protocols were compared between large (≥501beds) and small/middle-sized (≤500 beds) hospitals. RESULTS: Of 240 hospitals surveyed, 39 (16%; 18 large and 21 small/middle-sized) responded. The number of hospitals that intervened in the use of broad-spectrum antimicrobials within 7 and 28 d were 17 (44%) and 34 (87%), respectively; those that intervened for antifungals were 3 (8%) and 10 (26%), respectively. Interventions for use of broad-spectrum antimicrobials within 7 d were significantly more frequent in small/middle-sized hospitals compared to large hospitals [13 (61. 9%) vs. 4 (22. 2%), odds ratio = 5.7, 95% confidence interval = 1.4-23.3, p = 0.023]. CONCLUSIONS: Small/middle-sized hospitals had more frequent interventions within 7 d of broad-spectrum antimicrobial use than large hospitals. More effort to improve AFS is needed among all hospitals.

Travel medicine facilities: The first nationwide cross-sectional questionnaire survey in Japan.

INTRODUCTION: Travel medicine has gained importance in recent years; however, there is little data regarding travel medicine departments in Japanese hospitals. METHODS: This cross-sectional study contacted 488 hospitals designated by either the Japanese government or major Japanese associations. A questionnaire comprising 11 questions pertaining to the availability of pre-travel consultation, out-of-hours service for travel-related patients, number of medical doctors engaged in travel medicine and infectious disease specialists, and the number of negative pressure rooms available for inpatients and outpatients was distributed. It also asked about the facilities available to combat specific diseases like malaria, dengue, and post-exposure prophylaxis for rabies as these are most common diseases affecting returning travelers. RESULTS: Of the 263 hospitals (58.7%) that responded to our questionnaire, 82 hospitals (31.2%) provided pre-travel consulting, 188 hospitals (72.0%) accepted travel-related patients out-of-hours, median (interquartile range [IQR]) number of medical doctors involved in travel medicine was 1 (0-3), and median (IQR) number of patients accepted for admission was 2 (1-4). Only 106 (41%) hospitals could diagnose malaria at any time, 56 hospitals (21%) could immediately provide oral anti-malarial medicines; rapid diagnostic test for dengue was available in 99 hospitals (39%), while 67 hospitals (26%) could immediately administer post-exposure prophylaxis for rabies. CONCLUSIONS: Japan's medical care system is concerned about illnesses-especially malaria, dengue and rabies in returned travelers. We suggest construction of a medical care system centered on designated medical facilities for category I and II infectious diseases to build capacity for early diagnosis and treatment of common tropical infectious diseases.

Three cases diagnosed not Lyme disease but "tick-associated rash illness (TARI)" in Japan.

We report three cases of tick-associated rash illness (TARI) in Japan that presented with erythema migrans (EM) after a tick bite. Although EM is considered to be a characteristic finding of Lyme disease, EM can occur even if patient is not affected by Lyme disease and if it is bitten by a tick. In Japan, the vector of Lyme disease pathogens are not distributed in most areas, and patients with EM are unlikely to have Lyme disease. We aim to raise TARI awareness among physicians.

Infection with capsular genotype K1-ST23 hypervirulent Klebsiella pneumoniae isolates in Japan after a stay in East Asia: Two cases and a literature review.

Disseminated community-acquired infections caused by the hypervirulent Klebsiella pneumoniae (hvKp) among relatively healthy individuals in East Asia have been reported in recent years. Isolate of the capsular genotype K1, belonging to sequence type (ST) 23, is the most common causative agent of this disease. We experienced two cases of K1-ST23 infection with a travel history in East Asia, and hvKp infection was diagnosed after entering or returning to Japan. Case 1 was a 45-year-old Myanmar seaman with a history of ischemic heart disease who developed a fever on board and was transported to Japan via Shanghai and Taiwan. He had multiple disseminated lesions due to K. pneumoniae; other symptoms included liver abscess, intraocular inflammation, intraventricular thrombosis, brain abscess, and bloodstream infection. Along with antimicrobial treatment, drainage of liver abscesses and surgery for intraocular inflammation and intraventricular thrombosis were required. The patient was discharged 93 days after admission, with little improvement in the visual acuity. Case 2: A 29-year-old Japanese man with no underlying disease developed a prostate abscess and bloodstream infection caused by K. pneumoniae after a trip to Korea. However, he improved only with antimicrobial treatment. K. pneumoniae in both cases were identified to have the rmpA gene, with capsular genotypes K1 and ST23. Further, both cases were considered to have been infected with hvKp during their stay in East Asia. In conclusion, it is important to suspect disseminated disease and perform a systemic search, taking into account that hvKp may be present in cases of Klebsiella infection acquired from East Asia.

Effectiveness of personal protective equipment in preventing severe acute respiratory syndrome coronavirus 2 infection among healthcare workers.

INTRODUCTION: Information on the effectiveness of personal protective equipment (PPE) for preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among healthcare workers (HCWs), especially among HCWs with frequent contact with patients with SARS-CoV-2, is limited. METHODS: We conducted a prospective cohort study on 49 HCWs who worked in close contact with patients with SARS-CoV-2 infection. HCWs had blood samples taken every 2 weeks to test for SARS-CoV-2 antibodies using two different types of assay. RESULTS: Forty-nine participants (31 nurses, 15 doctors, 3 other workers) were enrolled. In total, 112 blood samples are obtained from participants. The median work days in 2 weeks was 9 (interquartile range (IQR): 5-10) days. In a single work day, 30 of the 49 participants (61.5%) had contact with patients with suspected or conformed SARS-CoV-2 at least 8 times, and approximately 60% of participants had more than 10 min of contact with a single patient. The median self-reported compliance to PPE was 90% (IQR: 80-100%). Seven participants tested positive for SARS-CoV-2 antibody using enzyme-linked immunosorbent assay (ELISA); however, none were seropositive for SARS-CoV-2 neutralizing antibody, so the positive ELISA results were assumed to be false-positive. CONCLUSIONS: The study provides evidence that appropriate PPE is sufficient to prevent infection amongHCWs. It is necessary to establish a system that provides a stable supply of PPE for HCWs to perform their duties.

Embryonic regeneration by relocalization of the Spemann organizer during twinning in Xenopus.

The formation of identical twins from a single egg has fascinated developmental biologists for a very long time. Previous work had shown that Xenopus blastulae bisected along the dorsal-ventral (D-V) midline (i.e., the sagittal plane) could generate twins but at very low frequencies. Here, we have improved this method by using an eyelash knife and changing saline solutions, reaching frequencies of twinning of 50% or more. This allowed mechanistic analysis of the twinning process. We unexpectedly observed that the epidermis of the resulting twins was asymmetrically pigmented at the tailbud stage of regenerating tadpoles. This pigment was entirely of maternal (oocyte) origin. Bisecting the embryo generated a large wound, which closed from all directions within 60 minutes, bringing cells normally fated to become Spemann organizer in direct contact with predicted ventral-most cells. Lineage-tracing analyses at the four-cell stage showed that in regenerating embryos midline tissues originated from the dorsal half, while the epidermis was entirely of ventral origin. Labeling of D-V segments at the 16-cell stage showed that the more pigmented epidermis originated from the ventral-most cells, while the less-pigmented epidermis arose from the adjoining ventral segment. This suggested a displacement of the organizer by 90°. Studies with the marker Chordin and phospho-Smad1/5/8 showed that in half embryos a new D-V gradient is intercalated at the site of the missing half. The displacement of self-organizing morphogen gradients uncovered here may help us understand not only twin formation in amphibians, but also rare cases of polyembryony.

Bighead is a Wnt antagonist secreted by the Xenopus Spemann organizer that promotes Lrp6 endocytosis.

The Xenopus laevis embryo has been subjected to almost saturating screens for molecules specifically expressed in dorsal Spemann organizer tissue. In this study, we performed high-throughput RNA sequencing of ectodermal explants, called animal caps, which normally give rise to epidermis. We analyzed dissociated animal cap cells that, through sustained activation of MAPK, differentiate into neural tissue. We also microinjected mRNAs for Cerberus, Chordin, FGF8, BMP4, Wnt8, and Xnr2, which induce neural or other germ layer differentiations. The searchable database provided here represents a valuable resource for the early vertebrate cell differentiation. These analyses resulted in the identification of a gene present in frog and fish, which we call Bighead. Surprisingly, at gastrula, it was expressed in the Spemann organizer and endoderm, rather than in ectoderm as we expected. Despite the plethora of genes already mined from Spemann organizer tissue, Bighead encodes a secreted protein that proved to be a potent inhibitor of Wnt signaling in a number of embryological and cultured cell signaling assays. Overexpression of Bighead resulted in large head structures very similar to those of the well-known Wnt antagonists Dkk1 and Frzb-1. Knockdown of Bighead with specific antisense morpholinos resulted in embryos with reduced head structures, due to increased Wnt signaling. Bighead protein bound specifically to the Wnt coreceptor lipoprotein receptor-related protein 6 (Lrp6), leading to its removal from the cell surface. Bighead joins two other Wnt antagonists, Dkk1 and Angptl4, which function as Lrp6 endocytosis regulators. These results suggest that endocytosis plays a crucial role in Wnt signaling.

Comparison of penicillins (penicillin G and ampicillin) and cefazolin as a definitive therapy against penicillin-susceptible Staphylococcus aureus (PSSA) bacteremia in Japan: a retrospective cohort study.

OBJECTIVES: Cefazolin has been the first-choice drug to treat penicillin-susceptible Staphylococcus aureus (PSSA) bacteremia, because oxacillin and nafcillin are not approved in Japan. Since February 2019, cefazolin supply is stagnant in Japan because of possible contamination issues. To look for cefazolin alternatives that can be used as a definitive therapy, we evaluated the usefulness of penicillins (penicillin G and ampicillin) against PSSA bacteremia. METHODS: A retrospective cohort study of patients with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia was conducted between January 2012 and September 2017. MSSA was determined according to the Clinical and Laboratory Standards Institute guidelines. PSSA was defined as S. aureus with penicillin G minimum inhibitory concentration of ≤0.03 mg/L without using the zone edge test or blaZ PCR. RESULTS: Of the 280 patients with MSSA bacteremia enrolled, and 138 (49.3%) was PSSA. Of the 44 patients who met the inclusion criteria, 11 were administered penicillins (penicillin G, n = 3 and ampicillin, n = 8) and 33 with cefazolin. Although the patients in the two groups had similar demographics, those in the penicillins group had significantly lower median Charlson score [interquartile range] than those in the cefazolin group (0[0-1] vs 1[0-4], p = 0.033). The two groups showed no significant differences regarding adverse events and bacteremia recurrence. None of the patients in the penicillins group died; however, 5 (15.2%) patients in the cefazolin group showed a 30-days mortality. CONCLUSION: Penicillins can be useful as a definitive therapy against PSSA bacteremia with stable condition, and they can be an alternative to cefazolin.

Difficulty of downscaling the precautions for coronavirus disease-19 based on negative throat polymerase chain results in the early phase of infection.

We here report a case of coronavirus disease-19 (COVID-19) in Japan in which the initial throat swab polymerase chain reaction result was negative The possibility of false-negative results in the early phase of disease suggest reconsideration of the feasibility of a community or national infection control framework to prevent transmission. We recommend establishing an alternative feasible system, such as self-isolation by contact history in non-endemic community and by symptoms in endemic community, not relying on the PCR examination, to minimize this ongoing COVID-19 outbreak. Further rapid accumulation of knowledge including incubation period, clinical course and types of transmission is warranted to control this outbreak.

Surveillance systems for healthcare-associated infection in high and upper-middle income countries: A scoping review.

BACKGROUND: Healthcare-associated infection (HAI) surveillance is useful for improved infection control. To understand the current HAI surveillance systems (HAISS) trend globally, a scoping review was performed. MATERIALS AND METHODS: The search strategy included academic literature review, Google search, and questionnaires by the Embassies of Japan (registration number: UMIN000036035). Eighty-two high and 56 upper-middle income countries defined by country income classification for the World Bank were targeted. The following information was reviewed: name of the system, official website, languages used in the official website, foundation year, operating body, survey type (prevalence or incidence), reporting periodicity, mode of participation (mandatory or voluntary), targeted medical facilities, targeted HAIs and definitions, targeted antimicrobial resistant pathogens, and parameters. Online accessibility of the official websites of the SS was assessed through Google search. RESULTS AND CONCLUSION: Forty-two (30.4%) countries (35 [42.7%] high and 7 [12.5%] upper-middle income countries) had national HAISS. Most systems operated on a voluntary basis, monitored HAI incidence, and used the Center for Disease Control and Prevention definitions. Methicillin-resistant Staphylococcus aureus, surgical site infection, and catheter-related blood stream infection were most commonly monitored. Surveillance for device-associated infections was implemented mainly in intensive care units. Thirty-five countries had at least one official website on their systems, while 7 (20.0%) were identified in the top 30 Google search hits, in English. Approximately half of the academic articles identified through PubMed were from three English-speaking countries. The feasibility and benefits of standardization of the HAI surveillance criteria and efficient feedback methods are future considerations.

Spemann organizer transcriptome induction by early beta-catenin, Wnt, Nodal, and Siamois signals in Xenopus laevis.

The earliest event in Xenopus development is the dorsal accumulation of nuclear ß-catenin under the influence of cytoplasmic determinants displaced by fertilization. In this study, a genome-wide approach was used to examine transcription of the 43,673 genes annotated in the Xenopus laevis genome under a variety of conditions that inhibit or promote formation of the Spemann organizer signaling center. Loss of function of ß-catenin with antisense morpholinos reproducibly reduced the expression of 247 mRNAs at gastrula stage. Interestingly, only 123 ß-catenin targets were enriched on the dorsal side and defined an early dorsal ß-catenin gene signature. These genes included several previously unrecognized Spemann organizer components. Surprisingly, only 3 of these 123 genes overlapped with the late Wnt signature recently defined by two other groups using inhibition by Dkk1 mRNA or Wnt8 morpholinos, which indicates that the effects of ß-catenin/Wnt signaling in early development are exquisitely regulated by stage-dependent mechanisms. We analyzed transcriptome responses to a number of treatments in a total of 46 RNA-seq libraries. These treatments included, in addition to ß-catenin depletion, regenerating dorsal and ventral half-embryos, lithium chloride treatment, and the overexpression of Wnt8, Siamois, and Cerberus mRNAs. Only some of the early dorsal ß-catenin signature genes were activated at blastula whereas others required the induction of endomesoderm, as indicated by their inhibition by Cerberus overexpression. These comprehensive data provide a rich resource for analyzing how the dorsal and ventral regions of the embryo communicate with each other in a self-organizing vertebrate model embryo.

A case of Klebsiella pneumoniae spondylitis and bacteremia potentially due to inflammation around a fecalith.

We herein report a case of Klebsiella pneumoniae (K. pneumoniae) spondylitis and bacteremia in a 90-year-old man with diabetes mellitus who had undergone sigmoidectomy and had a fecalith. Two months prior to admission, he had received antimicrobial treatment for 2 weeks for K. pneumoniae bacteremia whose entry was unclear and he was readmitted to our hospital owing to fever and stomachache. K. pneumoniae was isolated from two sets of blood cultures, and computed tomography and magnetic resonance imaging revealed inflammation and destruction of the 8th and 9th thoracic vertebra. The diagnosis was spondylodiscitis secondary to K. pneumoniae bacteremia. Although the entry point for K. pneumoniae was unclear, we suggest that inflammation of the mucosa around the fecalith might have caused the Enterobacteriaceae bacteremia.

Comparison of knowledge to antimicrobial stewardship institution policies targeting Staphylococcus aureus bacteremia and candidemia between medical doctors and pharmacists in an academic teaching hospital in Japan.

Staphylococcus aureus bacteremia (SAB) and candidemia have significant impacts on mortality. Both have important implications for antimicrobial stewardship programs (ASPs). However, there are limited data regarding who should be educated and what components should be considered for the ASPs. Hence, we investigated the possibility of the key elements for implications of SAB and candidemia managements for ASPs. We conducted a cross-sectional study on the knowledge of antimicrobial stewardship institution policies targeting SAB and candidemia for all medical doctors (MDs) and pharmacists to using an E-learning system. To compare the differences in proportions of appropriate knowledge between junior residents and other MDs, and all MDs and pharmacists, we performed bivariate analyses using Fisher's exact test and χ2 test with odds ratios (ORs) with 95% confidence intervals (CIs). In total, all 395 MDs (71 junior residents, 137 senior residents and fellows, and 187 attending doctors) and all 63 pharmacists including 4 antimicrobial stewardship teams pharmacists responded to survey. MDs other than junior residents responded significantly inappropriately to the questions on the candidemia than junior residents (OR = 0.6, 95% CI: 0.4-1.0). Pharmacists had a significantly lower proportion of appropriate knowledge to the candidemia than MDs (OR = 0.4, 95% CI: 0.2-0.8). The major pitfall was failure to consult an ophthalmologist (82.5%). Next step, we will conduct educational intervention about institution policies, and evaluate whether to improve the knowledges and practices by pre-post test and chart review.

Genome-wide analysis of dorsal and ventral transcriptomes of the Xenopus laevis gastrula.

RNA sequencing has allowed high-throughput screening of differential gene expression in many tissues and organisms. Xenopus laevis is a classical embryological and cell-free extract model system, but its genomic sequence had been lacking due to difficulties arising from allotetraploidy. There is currently much excitement surrounding the release of the completed X. laevis genome (version 9.1) by the Joint Genome Institute (JGI), which provides a platform for genome-wide studies. Here we present a deep RNA-seq dataset of transcripts expressed in dorsal and ventral lips of the early Xenopus gastrula embryo using the new genomic information, which was further annotated by blast searches against the human proteome. Overall, our findings confirm previous results from differential screenings using other methods that uncovered classical dorsal genes such as Chordin, Noggin and Cerberus, as well as ventral genes such as Sizzled, Ventx, Wnt8 and Bambi. Complete transcriptome-wide tables of mRNAs suitable for data mining are presented, which include many novel dorsal- and ventral-specific genes. RNA-seq was very quantitative and reproducible, and allowed us to define dorsal and ventral signatures useful for gene set expression analyses (GSEA). As an example of a new gene, we present here data on an organizer-specific secreted protein tyrosine kinase known as Pkdcc (protein kinase domain containing, cytoplasmic) or Vlk (vertebrate lonesome kinase). Overexpression experiments indicate that Pkdcc can act as a negative regulator of Wnt/ ß-catenin signaling independently of its kinase activity. We conclude that RNA-Seq in combination with the X. laevis complete genome now available provides a powerful tool for unraveling cell-cell signaling pathways during embryonic induction.