Function and anatomy of plant siRNA pools derived from hairpin transgenes

Background  

RNA interference results in specific gene silencing by small-interfering RNAs (siRNAs). Synthetic siRNAs provide a powerful tool for manipulating gene expression but high cost suggests that novel siRNA production methods are desirable. Strong evolutionary conservation of siRNA structure suggested that siRNAs will retain cross-species function and that transgenic plants expressing heterologous siRNAs might serve as useful siRNA bioreactors. Here we report a detailed evaluation of the above proposition and present evidence regarding structural features of siRNAs extracted from plants.     

Effects of fertilization and incubation factors on the quality and yield of scallop, Pecten fumatus Reeve, larvae

Variable quality and yield (percentage development from eggs) D-veligers of the scallop, Pecten fumatus Reeve, prompted assessment of fertilization and incubation protocols. Various sperm to egg ratios were tested on eggs suspended in sea water at different densities. Ratios of 1000:1 led to the highest D-veliger yield when eggs were incubated in suspension at one per millilitre. With increasing egg densities, the addition of 1000 sperm per egg led to increasing average numbers of sperm visible at the periphery of each egg, indicating that fewer sperm were necessary for fertilization at higher egg densities. The time period and temperature over which released gametes were stored before fertilization were also found to significantly affect D-veliger yield. Decreasing gamete storage temperature from 26 to 14^oC increased D-veliger yield, as did a reduction in the gamete storage period from 6 to 1 h. The incubation of embryos at densities in the 5-50 ml^-1 range did not affect D-veliger yield. A significant increase in total bacterial counts in the culture water occurred with increasing embryo stocking densities. However, presumptive Vibrionaceae counts did not increase significantly with increasing embryo stocking densities. In a comparison of the viability of self- and cross-fertilized embryos and larvae, fewer self-fertilized embryos developed to D-veliger stage; however, percentage survival, although highly variable, did not differ significantly in subsequent larval rearing. Cross-fertilized larvae had attained a significantly larger size by day 7.     

Causes of perinatal mortality in farmed fallow deer (Dama dama)

The causes of perinatal mortality in farmed fallow deer in the Camden region of New South Wales were determined between 1982 and 1987. The results of 144 necropsies on fawns showed that ante-parturient and parturient deaths occurred in 33 (22.9%) of cases, with post-parturient deaths accounting for 99 (69.8%), and undiagnosed causes the remaining 12 (8.3%). The most common cause of post-parturient death (43.1%) was exposure/starvation of fawns that had birthweights lower than the average for surviving fawns on these same farms (3.01 kg and 4.12 kg, respectively). These results provide good evidence of the correlation between low birthweight and perinatal mortality in fallow deer on Australian deer farms.     

The reversal of xylazine/ketamine immobilisation of fallow deer with yohimbine

Fallow deer were immobilised using a combination of xylazine and ketamine. Adult males (n = 10) and adult females (n = 10) received 4 mg/kg of each drug intramuscularly. Juveniles (n = 11) received 2 mg/kg of each drug, intravenously. Times to recumbency were as follows: adult males 4.9 +/- 2.9 min, adult females 4.1 +/- 1.9 min, juveniles 2.3 +/- 1.1 min. After 30 min each deer received 0.2 mg/kg of yohimbine, or an equal volume of sterile diluent intravenously. Yohimbine substantially reduced the recovery times of treated deer. Adults males were releasable 7.2 +/- 4.3 min after yohimbine administration, whereas control males were not releasable until 165 +/- 18 min. Treated adult females were releasable after 6.6 +/- 4.3 min, while control females were not releasable until 84 +/- 29 min. Juveniles were releasable 2.1 +/- 0.8 min after administration of yohimbine but control juveniles were not releasable until 62 +/- 16 min. Xylazine/ketamine administration produced statistically significant changes in packed cell volume, total plasma protein, albumin, sodium, glucose, creatine phosphokinase and inorganic phosphate values after 30 min. Yohimbine administration had no effect on these changes.     

Anasarca and myopathy in ostrich chicks

Twenty ostrich chicks that died at, or within, 1 week after hatching were examined from 7 farms with poor (43 to 75%) hatchability. All chicks had anasarca and 15 had mild, generalised, acute degenerative changes in the complexus and pelvic limb muscles. One had fibrinoid degeneration of arterioles. Biochemical examinations produced no evidence of deficiencies of selenium, vitamin A or vitamin E. The syndrome was related to high relative humidity during incubation. Malpositioning also was a cause of embryo mortality.     

Effect of copper smelting air pollution on the mites (Acari) associated with young Scots pine forests polluted by a copper smelting works at Giogów,Poland. I. Arboreal mites

Water, Air, &; Soil Pollution - The arboreal mites and epiphytes in young Scots pine forests (plant association Leucobryo-Pinetum) polluted by a copper smelting works at G?ogów, were...     

Compressibility, Phase Transitions, and Oxygen Migration in Zirconium Tungstate, ZrW2O8

In situ neutron diffraction experiments show that at pressures above 2 kilobars, cubic zirconium tungstate (ZrW2O8) undergoes a quenchable phase transition to an orthorhombic phase, the structure of which has been solved from powder diffraction data. This phase transition can be reversed by heating at 393 kelvin and 1 atmosphere and involves the migration of oxygen atoms in the lattice. The high-pressure phase shows negative thermal expansion from 20 to 300 kelvin. The relative thermal expansion and compressibilities of the cubic and orthorhombic forms can be explained in terms of the "cross-bracing" between polyhedra that occurs as a result of the phase transition.     

Retrospective comparison of the efficacy of fluconazole or itraconazole for the treatment of systemic blastomycosis in dogs

Background: Itraconazole is recommended for treatment of blastomycosis in dogs. Some evidence suggests that fluconazole might be less hepatotoxic than itraconazole. Objectives: To compare (1) incidence of clinical remission and death; (2) treatment duration; (3) total drug cost; (4) incidence of relapse; and (5) incidence of increased ALT activities in dogs with blastomycosis treated with fluconazole or itraconazole. Animals: One hundred and forty‐four dogs with systemic blastomycosis treated with itraconazole or fluconazole from 1998 to 2008. Methods: Retrospective case review. Information obtained included signalment, body weight, clinical signs, drug regimen, treatment duration, time to clinical remission, and laboratory results. Results: Neither treatment efficacy between fluconazole (75% remission) and itraconazole (90% remission) nor relapse rate (18% for itraconazole, 22% for fluconazole) was significantly different (P= .13, .75, respectively). Treatment duration was significantly longer for fluconazole (median 183 days) than for itraconazole (138 days; P= .001). Costs for fluconazole (median $1,223) were significantly less than for itraconazole ($3,717; P < .001). Incidence of increased ALT activities was not significantly different between groups (17% [3/18] for fluconazole, 26% [6/23] for itraconazole; P= .71). Conclusions: Fluconazole is associated with survival to clinical remission in 75% of dogs with blastomycosis. Although dogs receiving fluconazole were treated longer, drug costs were one‐third those of itraconazole. Hepatotoxicosis, as estimated by increases in serum ALT activity, can be observed with similar incidence for both drugs.