Visual Responses of Adult Asian Citrus Psyllid (Hemiptera: Liviidae) to Colored Sticky Traps on Citrus Trees

The effects of five differently-colored sticky traps in capturing adult Diaphorina citri were evaluated in citrus orchards. Trap catches of D. citri were monitored fortnightly on blue, green, red, white and yellow sticky cards placed on three citrus varieties during D. citri active flight period from April to July in south Texas. Evaluation of mean trap catches of each color by repeated measures analysis of variance produced three separate groups: yellow traps caught significantly more D. citri adults than the other four traps; red and green traps caught significantly more D. citri than blue and white traps, which were not significantly different. Although the number of adult psyllid captured on all trap types significantly increased with time during the trapping period, the performance of traps did not change with time. Trap catches were also significantly influenced by the citrus species; traps placed on lemon trees captured more D. citri than those placed on sweet orange and grapefruit, suggesting that plant preference exhibited by D. citri may influence the performance of traps. The ratio of trap reflectance between the 680 to 700 nm and the 450 nm was significantly correlated with total trap catches in all host species studied. Thus, this index was a good indicator of the attractiveness of adult D. citri to colored traps. Additionally, we compared the reflectance values of young versus mature flush shoots of the three host plants used in this study as related to densities of D. citri recorded in colored traps. We discussed the importance of visual cues in the host finding behavior of adult D. citri.     

Localization of pheochromocytoma by selective venous catheterization and assay of plasma catecholamines.

The diagnosis of pheochromocytoma rests primarily on determination of the 24-hour urinary excretion of catecholamines and their metabolites. In most cases nephrotomography and selective arteriography or venography, or both, are sufficient to localize the tumour. Selective venous catheterization and the assay of plasma catecholamines should be considered for pheochromocytoma localization in: (a) patients in whom standard techniques fail to localize the tumour; (b) patients who exhibit idiosyncratic reactions to the angiographic contrast materials; (c) young patients or patients with familial pheochromocytoma, including those with multiple neurofibromatosis or multiple endocrine adenomatosis, type 2; (d) patients with recurrent, malignant, or suspected multicentric or extra-adrenal tumours; and (e) patients excreting only norepinephrine in the urine. The validity of the results is particularly dependent on the skill with which venous catheterization is carried out.     

Activation of soluble guanylate cyclase from rat lung by incubation or by hydrogen peroxide.

A 37,000 X g supernatant fraction prepared from fat lung homogenate demonstrated a 2- to 3-fold increase in guanylate cyclase activity after incubation at 30 degrees for 30 min (preincubation). Treatment of the supernatant fraction with Triton X-100 increased activity to approximately the same extent as preincubation, but would not increase the activity after preincubation. By chromatography on Sepharose 2B, before and after preincubation, it was demonstrated that the increase in activity was only associated with the soluble guanylate cyclase, and not the particulate enzyme. Activation by preincubation required O2. It was completely inhibited by thiols such as 2-mercaptoethanol, and by bovine serum albumin, KCN, and sodium diethyldithiocarbamate. These inhibitors suggested a copper requirement for activation, and this was confirmed by demonstrating that 20 to 60 muM CuCl2 could relieve the inhibition by 0.1 mM sodium diethyldithiocarbamate. 2-Mercaptoethanol inhibition could also be reversed by removal of the thiol on a Sephadex G-25 column, however, this treatment partially activated the enzyme. Addition of 2-mercaptoethanol to a preincubated preparation would not reverse the activation. H2O2 was found to activate guanylate cyclase, either by its generation in the lung supernatant with glucose oxidase and glucose, or by its addition to a preparation in which the catalase was inhibited with KCN. KCN or bovine serum albumin was able to partially inhibit activation by glucose oxidase plus glucose, however, larger amounts of glucose oxidase could overcome that inhibition, indicating a catalytic role for Cu2+ at low H2O2 concentrations. No direct evidence for H2O2 formation during preincubation could be found, however, indirect evidence was obtained by the spectrophotometric detection of choleglobin formation from hemoglobin present in the lung supernatant fluid. The H2O2 is believed to result from the reaction of oxyhemoglobin with ascorbate.     

Parathyroid carcinoma: location of pelvic metastases by parathyroid hormone assay

A metastasis from a functioning parathyroid carcinoma was located by PTH radioimmunoassay and selective venous catheterization. The site of the metastasis, verified at autopsy, was in the right side of the pelvis. This is the most distant reported location for metastatic parathyroid carcinoma. The patient''s plasma immunoreactive PTH rose more than twofold in response to induced hypocalcemia. This suggests that relative hypocalcemia, induced therapeutically in such patients, may result in a higher chronic level of PTH secretion.     

INTENSITY DISCRIMINATION IN THE HUMAN EYE : II. THE RELATION BETWEENΔI/IAND INTENSITY FOR DIFFERENT PARTS OF THE SPECTRUM

1. A new apparatus is described for measuring visual intensity discrimination over a large range of intensities, with white light and with selected portions of the spectrum. With it measurements were made of the intensity ΔI which is just perceptible when it is added for a short time to a portion of a field of intensity I to which the eye has been adapted. 2. For white and for all colors the fraction ΔI/I decreases as I increases and reaches an asymptotic minimum value at high values of I. In addition, with white light the relation between ΔI/I and I shows two sections, one at low intensities and the other at high intensities, the two being separated by an abrupt transition. These findings are contrary to the generally accepted measurements of Koenig and Brodhun; however, they confirm the recent work of Steinhardt, as well as the older work of Blanchard and of Aubert. The abrupt transition is in keeping with the Duplicity theory which attributes the two sections to the functions of the rods and cones respectively. 3. Measurements with five parts of the spectrum amplify these relationships in terms of the different spectral sensibilities of the rods and cones. With extreme red light the relation of ΔI/I to I shows only a high intensity section corresponding to cone function, while with other colors the low intensity rod section appears and increases in extent as the light used moves toward the violet end of the spectrum. 4. Like most of the previously published data from various sources, the present numerical data are all described with precision by the theory which supposes that intensity discrimination is determined by the initial photochemical and chemical events in the rods and cones.     

Paired sequence difference in ribosomal RNAs: evolutionary and phylogenetic implications

Ribosomal RNAs have secondary structures that are maintained by internal Watson-Crick pairing. Through analysis of chordate, arthropod, and plant 5S ribosomal RNA sequences, we show that Darwinian selection operates on these nucleotide sequences to maintain functionally important secondary structure. Insect phylogenies based on nucleotide positions involved in pairing and the production of secondary structure are incongruent with those constructed on the basis of positions that are not. Furthermore, phylogeny reconstruction using these nonpairing bases is concordant with other, morphological data.      

Fatal Liver Damage After Barium Enemas Containing Tannic Acid

Tannic acid contained in the barium enema was found to have been the sole known potential hepatotoxin in four of the five cases of fulminating fatal liver failure that occurred in a 213-bed hospital over a period of 27 months. In the other case halothane anesthesia had also been administered. Autopsies (performed on four of the cases) did not suggest viral hepatitis but showed substantially indentical hepatic changes, not unlike those reported in the past following tannic acid exposure. Proof is not claimed that tannic acid was the cause of these deaths, but further investigation regarding the safety of its administration in barium enemas is advocated.     

Diurnal Patterns of Flight Activity and Effects of Light on Host Finding Behavior of the Asian Citrus Psyllid

The Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), is an invasive pest of citrus in the United States. The psyllid feeds and reproduces primarily on new flush growth of citrus and other rutaceous plants. Because it vectors the bacterial causal agents of the deadly citrus greening disease, D. citri is potentially a pest of economic importance in all citrus growing areas where it occurs together with the disease. We investigated the diurnal patterns of its flight activity in the field and the effects of light on its host selection and egg laying behaviors. The numbers of adult psyllids caught on yellow sticky traps were 3 to 4-fold higher during daytime than nighttime. Daytime flight activity of D. citri adults also varied with time of the day with peak catches occurring at midday from 1200 to 1500 h. Illumination of the traps at night increased their attractiveness to adult psyllids by 5-fold. Similarly, light significantly increased plant colonization by adults and female egg deposition on potted plants in the laboratory. These results showed that the flight activity and host selection behavior of adult psyllids are regulated by light and circadian rhythms. Thus, adult psyllids utilize light as visual cues in their host-plant selection process.