The effect of membrane stabilizers on phytochrome-controlled anthocyanin biosynthesis in Brassica oleracea

The promotion of anthocyanin synthesis in red-cabbage seedlings by 5 min exposure to R light is inhibited by subsequent application of CaCl₂. The stimulation of dark synthesis of anthocyanin by n-PrOH and by kinetin is also reduced by Ca²⁺ and by cholesterol, both of which are well known to stabilize cell membranes. By contrast, EDTA, which chelates Ca²⁺, promotes dark synthesis of anthocyanin. Assay of native Ca²⁺ extractable from seedlings immersed in EDTA demonstrates that R light exposure promotes a highly significant increase in extractable Ca²⁺. It is suggested that the molecular configuration of the phytochrome molecule affects the ability of a membrane to bind Ca²⁺ and that this in turn affects the permeability to substrates which are required for anthocyanin biosynthesis.     

Taxonomy and distribution of fresh water Ostracoda from Socotra Island,Yemen

Eleven species belonging to ten genera of fresh water Ostracoda, have been identified from thirteen sediment samples collected from the bottom of permanent streams running along the N-NE part of Socotra Island. The fauna shows close affinity with the S-E African and S-E Asian assemblages, with interesting findings regarding the Palearctic Limnocythere stationis Vávra, 1891. The taxonomy and geographic distribution of the fauna are here discussed in detail.     

The psychosis spectrum in a young U.S. community sample: findings from the Philadelphia Neurodevelopmental Cohort

Little is known about the occurrence and predictors of the psychosis spectrum in large non‐clinical community samples of U.S. youths. We aimed to bridge this gap through assessment of psychosis spectrum symptoms in the Philadelphia Neurodevelopmental Cohort, a collaborative investigation of clinical and neurobehavioral phenotypes in a prospectively accrued cohort of youths, funded by the National Institute of Mental Health. Youths (age 11‐21; N=7,054) and collateral informants (caregiver/legal guardian) were recruited through the Children's Hospital of Philadelphia and administered structured screens of psychosis spectrum symptoms, other major psychopathology domains, and substance use. Youths were also administered a computerized neurocognitive battery assessing five neurobehavioral domains. Predictors of psychosis spectrum status in physically healthy participants (N=4,848) were examined using logistic regression. Among medically healthy youths, 3.7% reported threshold psychotic symptoms (delusions and/or hallucinations). An additional 12.3% reported significant sub‐psychotic positive symptoms, with odd/unusual thoughts and auditory perceptions, followed by reality confusion, being the most discriminating and widely endorsed attenuated symptoms. A minority of youths (2.3%) endorsed subclinical negative/disorganized symptoms in the absence of positive symptoms. Caregivers reported lower symptom levels than their children. Male gender, younger age, and non‐European American ethnicity were significant predictors of spectrum status. Youths with spectrum symptoms had reduced accuracy across neurocognitive domains, reduced global functioning, and increased odds of depression, anxiety, behavioral disorders, substance use and suicidal ideation. These findings have public health relevance for prevention and early intervention.     

The effect of kinetin in relation to photocontrol of anthocyani biosynthesis in Brassica oleracea

Kinetin stimulates the synthesis of anthocyanin in dark-grown seedlings of red-cabbage. When applied for only 15 min its effect resembles that of 5 min R light and can be nullified by a subsequent exposure to 5 min FR. However, kinetin fails to stimulate PAL activity in the dark-grown seedlings. It is suggested that the effect of kinetin, like that of R light, may be to increase membrane permeability, allowing a pool of endogenous substrate to reach the site of anthocyanin biosynthesis.     

Allometric growth ratios are independent of Igf2 gene dosage during development

In the mouse, allelic dosage of the paternally expressed gene coding for insulin-like growth factor II (Igf2), from null to bi-allelic, results in dose-dependent growth, an effect which appears to be fully established during a discrete period of embryogenesis that then persists throughout life. Here, we specifically quantify the influence of Igf2 allelic dosage on the proportionality of regional embryonic growth rather than overall growth. Remarkably, preservation of allometric growth ratios between head and body regions were observed throughout development, irrespective of the range of overall growth phenotype (60-130% of wild type). Evaluation of log-log plots suggests that each allele of Igf2 expressed corresponds to the equivalent of 2-4 days of relative growth. Igf2 is predominantly expressed in extra-embryonic mesoderm (E7.5-E8.25), 24 h before alterations in cell number are known to occur in embryos with disruption of the paternally expressed allele. We hypothesized that the preservation of proportionality may result from modification of extra-embryonic development and subsequent alteration of systemic nutritional supply. Morphological analyses of chorio-allantoic and placental development between E9 and E9.5 appeared Igf2 independent. This suggests either an intrinsic but systemic Igf2-dependent activity within the embryo or a more complex developmental mechanism accounts for the proportional phenotype. Allelic IGF2 expression is subject to stochastic variation in humans, with 10% of the population estimated to be functionally bi-allelic. Evaluation of allometric growth of normal and pathological human embryos, suggest intra-uterine growth phenotypes associated with altered IGF2 imprinting are also likely to be proportionate.     

Tumor ablation with irreversible electroporation

We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop during the application of the pulses were used to design an efficient treatment protocol with minimal heating of the tissue. Tumor regression was confirmed by histological studies which also revealed that it occurred as a direct result of irreversible cell membrane permeabilization. Parametric studies show that the successful outcome of the procedure is related to the applied electric field strength, the total pulse duration as well as the temporal mode of delivery of the pulses. Our best results were obtained using plate electrodes to deliver across the tumor 80 pulses of 100 micros at 0.3 Hz with an electrical field magnitude of 2500 V/cm. These conditions induced complete regression in 12 out of 13 treated tumors, (92%), in the absence of tissue heating. Irreversible electroporation is thus a new effective modality for non-thermal tumor ablation.