Intervessel pits act as safety valves that prevent the spread of xylem embolism. Pectin-calcium crosslinks within the pit membrane have been proposed to affect xylem vulnerability to cavitation. However, as the chemical composition of pit membranes is poorly understood, this hypothesis has not been verified. Using electron microscopy, immunolabeling, an antimonate precipitation technique, and r...

A selective separation method based on anion exchange cartridge was developed to determine antimony (Sb) speciation in biological matrices by graphite furnace atomic absorption spectrophotometry (GFAAS). The selectivity of the cartridge towards antimonite [Sb(III)] and antimonate [Sb(V)] reversed in the presence of deionized (DI) water and 2mM citric acid. While Sb(V) was retained by the cartri...

The ultrastructural localization of mobilizable Ca2+ in different subcellular compartments of human oocytes and preimplantation embryos was studied using the potassium-pyroantimonate technique and transmission electron microscopy; the specificity was confirmed by chelation experiments and X-ray microanalysis. In unfertilized oocytes, Ca2+ was detected in small vesicles beneath the plasma membra...

HUANG, S-S. (The Institute of Chinese Medicine of Guangdong province, Guangzhou, 510520, China), J.-P. LIAO (South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China). AND B. K. KIRCHOFF (University of North Carolina at Greensboro, Department of Biology, Greensboro, NC 27402), Calcium distribution and function in the glandular trichomes of Lavandula pinnata L. J. Torr...

We report the case of a 33-year-old man referred to our department with a skin ulcer that had appeared 1 year earlier on the left posterior axillary fold. His medical history was remarkable for chronic hepatitis B infection being treated with adefovir and for psoriatic arthritis, under treatment with leflunomide 20 mg/d, prednisone 5 mg/d, and infliximab 5 mg/kg every 8 weeks for the past 2 yea...

The plasma membrane of Paramecium is underlain by a continuous layer of membrane vesicles known as cortical alveoli, whose function was unknown but whose organization had suggested some resemblance with muscle sarcoplasmic reticulum. The occurrence of antimonate precipitates within the alveoli first indicated to us that they may indeed correspond to a vast calcium storage site. To analyze the p...

The Indian subcontinent is the only region where arsenic contamination of drinking water coexists with widespread resistance to antimonial drugs that are used to treat the parasitic disease visceral leishmaniasis. We have previously proposed that selection for parasite resistance within visceral leishmaniasis patients who have been exposed to trivalent arsenic results in cross-resistance to the...

of 1.3 mg/kg for 7 days in combination with 5 (mg/kg)/day of chloroquine. Antileishmanial Test Method. The antileishmanial activity of 2d was determined in golden hamsters by the method of Hanson et Male golden hamsters were inoculated intracardially with lo7 amastigotes of the Khartoum strain of Leishmania donovani. Administration of the drug was begun 3 days after inoculation and was continue...

Six arsenic species [arsenate, arsenite, arsenocholine, arsenobetaine, monomethyl arsonic acid, and dimethyl arsinic acid] present in human urine were determined using ion-exchange chromatography combined with inductively coupled plasma mass spectrometry (IC-ICP-MS). Baseline separation was achieved for all six species as well as for the internal standard (potassium hexahydroxy antimonate V) in...

Even though antimony (Sb) and arsenic (As) are chemical analogs, differences exist on how they are taken up and translocated in plants. We investigated 1) Sb uptake, efflux and speciation in arsenic hyperaccumulator Pteris vittata after 1 d exposure to 1.6 or 8 mg/L antimonite (SbIII) or antimonate (SbV), 2) Sb uptake by PV accessions from Florida, China, and Brazil after 7 d exposure to 8 mg/L...