Local Adaptation of Bitter Taste and Ecological Speciation in a Wild Mammal.

Sensory systems are attractive evolutionary models to address how organisms adapt to local environments that can cause ecological speciation. However, tests of these evolutionary models have focused on visual, auditory, and olfactory senses. Here, we show local adaptation of bitter taste receptor genes in two neighboring populations of a wild mammal-the blind mole rat Spalax galili-that show ecological speciation in divergent soil environments. We found that basalt-type bitter receptors showed higher response intensity and sensitivity compared with chalk-type ones using both genetic and cell-based functional analyses. Such functional changes could help animals adapted to basalt soil select plants with less bitterness from diverse local foods, whereas a weaker reception to bitter taste may allow consumption of a greater range of plants for animals inhabiting chalk soil with a scarcity of food supply. Our study shows divergent selection on food resources through local adaptation of bitter receptors, and suggests that taste plays an important yet underappreciated role in speciation.

Transcriptomic Analysis Provides Insights into Grafting Union Development in Pecan (Carya illinoinensis).

Pecan (Carya illinoinensis), as a popular nut tree, has been widely planted in China in recent years. Grafting is an important technique for its cultivation. For a successful grafting, graft union development generally involves the formation of callus and vascular bundles at the graft union. To explore the molecular mechanism of graft union development, we applied high throughput RNA sequencing to investigate the transcriptomic profiles of graft union at four timepoints (0 days, 8 days, 15 days, and 30 days) during the pecan grafting process. After de novo assembly, 83,693 unigenes were obtained, and 40,069 of them were annotated. A total of 12,180 differentially expressed genes were identified between by grafting. Genes involved in hormone signaling, cell proliferation, xylem differentiation, cell elongation, secondary cell wall deposition, programmed cell death, and reactive oxygen species (ROS) scavenging showed significant differential expression during the graft union developmental process. In addition, we found that the content of auxin, cytokinin, and gibberellin were accumulated at the graft unions during the grafting process. These results will aid in our understanding of successful grafting in the future.

Urbanicity-related variation in help-seeking and services utilization among preschool-age children with autism in Taiwan.

The present study examines urbanicity-related differences in help-seeking process among preschool children with autism and investigates the factors associated with utilization of autism-related services within the year of diagnosis. Using the 1997-2004 National Health Insurance Research Database (NHIRD) in Taiwan, we identified a total of 3495 autistic children born in 1997-1999 and 13964 matched controls. Results indicate that suburban and rural autism tended to receive the diagnosis at an older age and to have a longer diagnosis process as compared with urban counterparts. Male gender, a younger age of diagnosis, and being diagnosed by psychiatric specialty strongly predict subsequent greater utilization of autism-specific services (all p < 0.05). Health policy makers and other service providers should address the needs of children with early-onset neurodevelopmental disorders in rural areas, particularly those from disadvantaged families.

Factors associated with the diagnosis of neurodevelopmental disorders: a population-based longitudinal study.

OBJECTIVES: We investigated the occurrence of newly diagnosed mental retardation, attention-deficit/hyperactivity disorder, and autism and sociodemographic factors associated with their distribution in Taiwan, and we examined urbanicity- and socioeconomic status-associated differences in the age at first diagnosis. METHODS: The data for this study were derived from the 1996-2004 National Health Insurance Research Database in Taiwan. Approximately 1.8 million beneficiaries born between 1996 and 2001 were identified, with follow-up periods ranging from 3 to 8 years. RESULTS: Each of the 3 neurodevelopmental disorders had distinct incidence rates and associated factors. For example, as compared with the birth years of 1996-1999, the rate of autism increased 14% during the period 2000-2004, whereas the rate of newly diagnosed mental retardation decreased 42% to 50% over the same period. An elevated incidence rate for attention-deficit/hyperactivity disorder and autism was observed in later birth cohorts. The risk of receiving a diagnosis of mental retardation for children in rural areas and of lower socioeconomic status was reduced in early childhood and increased in school ages as compared with their urban and higher socioeconomic status counterparts. CONCLUSIONS: Variation in the rate of newly diagnosed mental retardation, attention-deficit/hyperactivity disorder, and autism among children in Taiwan depended on age, birth year, period, and socioeconomic status. The extent of the association linking age with the first diagnosis of mental retardation varies across different urbanicity level and socioeconomic status.

Effect of regression of enlarged neck lymph nodes on radiation doses received by parotid glands during intensity-modulated radiotherapy for head and neck cancer.

OBJECTIVES: The regression of enlarged neck lymph nodes during intensity-modulated radiotherapy (IMRT) may increase actual radiation doses to the parotid glands of patients with head-and-neck cancer. We investigated the changes in the lymph nodes volume during IMRT and the effect of these changes to the parotid gland doses. METHODS: Ten head and neck cancer patients with enlarged neck lymph nodes were enrolled in this study. Computed tomography (CT) imaging was repeated to evaluate the change in lymph nodes volume after initial 45 Gy, and the second part of IMRT (21 Gy) was then replanned to reflect the change of nodal tumor volume. The dosimetric benefit of parotid sparing with replanning was compared with that of no replanning. RESULTS: The enlarged neck lymph nodes in all patients pushed the parotid glands outward in pretreatment CT images. After 45 Gy of IMRT, nodal regression caused the parotid glands to shift inward into the high-dose area. When compared with those without replanning, we found modification of IMRT plan after 45 Gy significantly reduced radiation dose to parotid glands (mean reduction of 2.95 +/- 1.10 Gy to the left and 3.23 +/- 1.37 Gy to the right, respectively; P < 0.001). CONCLUSIONS: Excessive parotid gland doses secondary to the regression of enlarged neck nodes could be mitigated by replanning after 45 Gy. However, recontouring of large lymph nodes that regress during therapy has a risk of under-dosing extracapsular extension of lymph node metastases. Therefore, recontouring should be done with extreme caution.