Intracellular calcium activity in split frog skin epithelium: Effect of cAMP

Summary Measurement of intracellular calcium activity (a _Ca ^c ) by ion-selective microelectrodes has previously been technically limited to relatively large cells (20 m). We now report results obtained with this technique in the small epithelial cells (10 m) of split frog skin using microelectrodes having an outer tip diameter of <0.2 m. The basolateral membrane potential was measured with Ca²⁺-selective microelectrodes (E _Ca ^sc ) and with reference micropipettes ( ^sc ) either sequentially or simultaneously in 15 successful experiments. Under baseline conditions,a _Ca ^c was measured to be 215±39nm (mean±se), in close agreement with the mean values estimated from published data obtained withNecturus proximal tubule. Stimulation of Na⁺ transport across six skins with 1mm serosal 8p-chlorophenylthio-3,5 cyclic AMP (CPTcAMP) increaseda _Ca ^c by a factor of 2.6±0.6. The increase ina _Ca ^c preceded the CPTcAMP-induced increase inI _sc. The results of the present study indicate that electrometric determination of intracellular calcium activity is now feasible in a much wider range of cell systems than heretofore possible. CPT cAMP elevates intracellular Ca²⁺ activity; this phenomenon is an early event, preceding the natriferic effect of CPTcAMP.     

Thiazides stimulate calcium absorption in urinary bladder of winter flounder

Thiazides inhibit voltage-independent NaCl absorption in the urinary bladder of the winter flounder presumably by blocking an electroneutral mucosal Na/Cl co-transporter. As thiazides stimulate calcium absorption in mammalian distal convoluted tubule while inhibiting NaCl absorption, we studied the effects of hydrochlorothiazide (HCTZ) on unidirectional 45Ca fluxes and intracellular electrical potential in short-circuited bladders to examine possible mechanisms of HCTZ effects on calcium transport. Basal secretory calcium flux was, on average, slightly larger than absorptive flux, reflecting small net calcium secretion. Mucosal addition of HCTZ (10(-4) M) stimulated absorptive calcium flux by 46% while the secretory flux was unaltered. Thus, HCTZ tended to induce net calcium absorption. Pre-treatment with serosal ouabain (10(-4) M) attenuated the HCTZ-induced increase in absorptive calcium flux. Moreover, HCTZ hyperpolarized the mucosal membrane potential by 18% as measured by conventional open-tip microelectrodes. These effects of HCTZ are consistent with the hypothesis that HCTZ indirectly stimulates Na/Ca exchange located at the serosal membrane. In conclusion, HCTZ in flounder urinary bladder, as in mammalian distal convoluted tubule, simultaneously inhibits NaCl absorption and stimulates calcium absorption. This study expands on the functional similarities between the flounder urinary bladder and the mammalian distal convoluted tubule.     

Regulation of neonatal liver protein synthesis by insulin and amino acids in pigs

The high efficiency of protein deposition during the neonatal period is driven by high rates of protein synthesis, which are maximally stimulated after feeding. Infusion of amino acids, but not insulin, reproduces the feeding-induced stimulation of liver protein synthesis. To determine whether amino acid-stimulated liver protein synthesis is independent of insulin in neonates, and to examine the role of amino acids and insulin in the regulation of translation initiation in neonatal liver, we performed pancreatic glucose-amino acid clamps in overnight-fasted 7-day-old pigs. Pigs (n = 9-12/group) were infused with insulin at 0, 10, 22, and 110 ng.kg(-0.66).min(-1) to achieve 0, 2, 6, and 30 microU/ml insulin, respectively. At each insulin dose, amino acids were maintained at fasting or fed levels or, in conjunction with the highest insulin dose, allowed to fall to below fasting levels. Insulin had no effect on the fractional rate of protein synthesis in liver. Amino acids increased fractional protein synthesis rates in liver at each dose of insulin, including the 0 microU/ml dose. There was a dose-response effect of amino acids on liver protein synthesis. Amino acids and insulin increased protein S6 kinase and 4E-binding protein 1 (4E-BP1) phosphorylation; however, only amino acids decreased formation of the inactive 4E-BPI.eukaryotic initiation factor-4E (eIF4E) complex. The results suggest that amino acids regulate liver protein synthesis in the neonate by modulating the availability of eIF4E for 48S ribosomal complex formation and that this response does not require insulin.     

A high‐throughput detection method for invasive fruit fly (Diptera: Tephritidae) species based on microfluidic dynamic array

Invasive species can be detrimental to a nation's ecology, economy and human health. Rapid and accurate diagnostics are critical to limit the establishment and spread of exotic organisms. The increasing rate of biological invasions relative to the taxonomic expertise available generates a demand for high‐throughput, DNA‐based diagnostics methods for identification. We designed species‐specific qPCR primer and probe combinations for 27 economically important tephritidae species in six genera (Anastrepha, Bactrocera, Carpomya, Ceratitis, Dacus and Rhagoletis) based on 935 COI DNA barcode haplotypes from 181 fruit fly species publically available in BOLD, and then tested the specificity for each primer pair and probe through qPCR of 35 of those species. We then developed a standardization reaction system for detecting the 27 target species based on a microfluidic dynamic array and also applied the method to identify unknown immature samples from port interceptions and field monitoring. This method led to a specific and simultaneous detection for all 27 species in 7.5 h, using only 0.2 μL of reaction system in each reaction chamber. The approach successfully discriminated among species within complexes that had genetic similarities of up to 98.48%, while it also identified all immature samples consistent with the subsequent results of morphological examination of adults which were reared from larvae of cohorts from the same samples. We present an accurate, rapid and high‐throughput innovative approach for detecting fruit flies of quarantine concern. This is a new method which has broad potential to be one of international standards for plant quarantine and invasive species detection.     

Asian Primate Species Richness Correlates with Rainfall

Previous studies of meta-analyses found significantly positive correlations between primate species richness and rainfall for Africa, Madagascar and the Neotropics, with the exception of Asia, leaving the open question whether that anomaly is the result of sampling bias, biogeography, or some other factor. This study re-examines the question using modelled data, with primate species richness data from the Southeast Asian Mammals Databank and rainfall data from the Climatic Research Unit. Data processing with Geographical Information Systems resulted in 390 sample points. Reduced major axis and ordinary least squares regressions were employed to examine the relationship for six regions, including the whole study area of Southeast Asia, and the subareas of Huxley West, Huxley East, Mainland Southeast Asia, Borneo, and Sumatra. The results showed a significant positive relationship between primate species richness and mean annual rainfall for Southeast Asia (r = 0.26, P<0.001). Comparing the results for the large islands and Mainland Southeast Asia showed that Sumatra had the highest correlation (r = 0.58; P<0.05). After controlling for the major biogeographic effect associated with Huxley’s Line, our results showed that primate species richness is positively associated with mean annual rainfall in Southeast Asia. Our findings contrast to prior studies of meta-analyses that showed no relationship between rainfall and primate species richness in Asia, and thereby bring Asia into agreement with results showing significant positive correlations between rainfall and primate species richness everywhere else in the world. The inference is that previous anomalous results for Asia were result of sampling bias in the meta-analysis.     

Body measurements correlation and x-ray imaging of three Hystrix javanica fetuses in different fetal development stages

Hystrix javanica is endemic species in Indonesia. Study about fetal development of Hystrix javanica are very rare because of sample limitation. This study was carried out to describe the morphometrics and x-ray analysis of three fetuses in different stage to give basic information about fetal development of Hystrix javanica. Three fetus samples fixed in Bouin’s solution was used in this study. Observation was carried out to identify the characteristic of three fetus samples. This included the pattern of hair, body measurements, body volume, and body weight. X-ray analysis was carried out to know the ossification process in the fetal development. Statistical analysis was carried out using Microsoft 365® Excel program software. Three fetus samples had different specific hair pattern, that was hairless, smooth hairs, and smooth hairs with dense-non dense pattern. Body volume of 1^st, 2^nd, and 3^rd fetus were 23mL, 90mL, and 170mL, respectively. Body weight of 1^st, 2^nd, and 3^rd fetus were 19.5g, 79.22g, and 153.18g, respectively. Pearson’s correlation analysis shown strong relationship between total body length, front body length, back body length, horizontal body diameter, vertical body diameter, head length, and head diameter against body volume and body weight of three fetuses. Significant positive correlation was shown between horizontal body diameter, vertical body diameter, and head diameter against body volume and body length with P value < 0.05. Faint radiopaque images showed in the 2^nd fetus sample and strong radiopaque images showed in the 3^rd fetus sample. Radiopaque images were identified in the teeth, cranium, vertebrae, and extremities bones. In this study we concluded that there was a specific hair pattern in different fetal stage. All body measurements have positive correlation with body volume and body weight and x-ray analysis shown that the ossification of the bone was started to happen while the smooth hair was growth.