The occurrence and correction of boron deficiency

Positive responses to B application, which provide clear evidence of B deficiency, have been reported in over 80 countries and on 132 crops over the last 60 years. It is estimated that about 15 million ha are annually treated with B. In a few regions in the world, B deficient soils exist over a wide area, as for example in eastern and southern China. Elsewhere B deficiency is restricted to particular soil types and crops. Acrisols and Podzols and to a much lesser extent Andosols, Luvisols and Ferralsols, appear to be the soil groups most likely to produce B deficient crops. Soil parent material and texture are considered to be the major soil factors associated with the occurrence of B deficiency. For many crops it is the B requirement for successful fertilisation that is of critical importance; even crops with a small B requirement, such as the cereals, can suffer impaired seed set due to B shortage at a critical time. Climate, particularly high light intensity and low temperature are factors that need to be considered in relation to the occurrence of B deficiency. Boron deficiency can be readily prevented and corrected by both soil and foliar applications. Most reliance is placed on refined sodium borates, but crushed ores are used both in the manufacture of boronated fertilisers and on their own. Depending on the ore, its particle size and method of application, B supply may be extended by using an ore which dissolves slowly.     

The biological occurrence and trafficking of cobalt

Cobalt is an essential trace element in both prokaryotes and eukaryotes. Nevertheless, it occurs less frequently in metalloproteins than other transition metals. This low occurrence appears to be due to the metal's low abundance in nature as well as its competition with iron, whose biologically critical functions include respiration and photosynthesis. In this review, we discuss the biological role of cobalt, the major effects of cobalt on iron utilization, as well as several mechanisms that cells have developed to circumvent the toxicity of cobalt while still exploiting its chemistry.     

On the occurrence of a high content of cytokinins in rice callus tissues

Rice callus tissues contained at least three active cytokinincompounds: zeatin, its riboside and N⁶-(²-isopentenyl) adenosine.These butanol-extractable cytokinins were identified by theirchromatographic mobilities in Sephadex LH-20, paper and gaschromatography. Zeatin, the apparent major cytokinin, was presentat concentrations of 0.7 to 1.0 µg/g fresh tissue and1.3 to 1.7 µg/g fresh tissue in 10^–7 M and 10^–55M 2,4-D callus, respectively. On the basis of these and earlierresults, the induction and growth of rice callus tissue is discussedin relation to the occurrence of cytokinins in the tissue. (Received December 27, 1978; )     

Metallothionein, zinc, and mercury levels in tissues of young rats exposed to zinc and subsequently to mercury

Several studies have described mercury toxicity and the role of metallothioneins (MT) in the detoxification and regulation of metal homeostasis. However, little data exist on this topic during the specific post-natal developmental phase in young mammals. This developmental phase is particularly important since young animals are more sensitive to toxicants than adults. The objective of this work was to investigate whether MT participates in the mechanism of protection conferred by zinc pre-treatment on the toxic effects induced by mercury in neonate rats. Pups were exposed to ZnCl(2) (5 doses of 27 mg/kg/day, s.c.) and subsequently to HgCl(2) (5 doses of 5 mg/kg/day, s.c.); metal (Zn and Hg) and MT contents were analyzed in the liver, kidney, and blood. MT was induced in the liver and kidney of pups of both Zn-sal and Zn-Hg groups, although the greatest increase was in neonates exposed to Zn only. A direct relationship exists between MT and metals for both hepatic and renal tissues, which indicates that the increase in metal levels occurs in parallel to the increase in MT content. Although the heat-treated cytosolic fraction is rich in MT and metals, higher Zn and Hg contents were detected in the insoluble fraction of all tissues. These results suggest that MT is, at least in part, responsible for preventing Hg accumulation in the liver and blood and decreasing renal toxicity.     

Comparative distributions of zinc, cadmium and mercury in the tissues of experimental mice

Different groups of mice were injected with cadmium, zinc and mercury. Zinc injections had no effect on zinc tissue levels while both mercury and cadmium accumulated in various tissues. Cadmium persisted in the tissues much longer than mercury, and while the mercury concentrations began to decline as soon as dosing ceased, cadmium concentrations in kidney and intestine increased even after dosing ceased. There appeared to be an interrelationship between cadmium concentrations in spleen and intestine which warrants some further investigations. There was a linear, but discontinuous, effect of cadmium on zinc concentrations in liver, kidney and pancreas which may depend on metallothionein biochemistry. Mercury injections had no effect on zinc metabolism. It is proposed that differences in the rate of excretion of cadmium and mercury from the kidney could explain the differential accumulation of cadmium and mercury in animals.     

Comparative accumulation of manganese and boron in barley tissues

Summary The uptake of Mn and B by barley plants was studied in a 5-week period in growth chambers. Fluorescent light was provided with an intensity of 3200 foot-candles in a 12-hour day length and the entire plants were grown at temperatures of 10°, 15°, or 20°C. The root medium consisted of a base nutrient solution in which Mn or B was added in the following concentrations: 0, 0.1, 0.5, 2.0, and 5.0 ppm. Five plants were grown in volumes of 20 liters of solution. At the end of the growth period the shoots and roots were analyzed for Mn and B. The Mn content of the roots increased with temperature and with the Mn concentration of the external solution while the B content remained virtually static regardless of temperature or solution concentration. The shoots were divided into young, mature, and old leaves. The Mn and B content of the old leaves showed increases which varied both with temperature and concentration. Similar results were obtained with young and mature leaves. The failure of B to accumulate in the roots was discussed. It was suggested that boric acid, with a very low degree of dissociation, is present largely in a molecular form and does not participate in the customary metabolic activity connected with ion uptake and accumulation in roots.     

Towards new boron carriers for boron neutron capture therapy: Metallacarboranes bearing cobalt,iron and chromium and their cholesterol conjugates

A method for the synthesis of cholesterol–metallacarborane conjugates bearing cobalt, iron and chromium was developed. Effective incorporation of the cholesterol conjugate bearing cobalt into liposome membrane was revealed. Using the metallacarborane-encrusted liposomes as boron delivery system in vivo biodistribution experiments in tumor-bearing mice, high accumulation and selective delivery of boron into tumor tissues was observed. The results demonstrate that the cholesterol–metallacarborane conjugates can be considered as a potential candidate for boron delivery vehicle in BNCT.     

Determination of trace boron in microsamples of biological tissues

A benign-by-design method for the determination of boron (B) in microsamples of biological tissues was developed. This is a simple, automated, microdigestion method. Use of reagents and generation of waste are minimized, and the use of toxic/hazardous reagents is eliminated as compared to currently available B methodology. Microsamples are accommodated by the method; 100–400 mg sam ples were used in this study. B is determined by inductively coupled plasma atomic emission spectrometry (ICPAES) at 249.678 nm. The instrument detection limit for B is 0.01 Μg/mL. Interference studies have been investigated for 21 common elements. Over 250 analyses of standard reference materials were analyzed during the study dura tion. Recoveries for a series of biological tissues, both plant and ani mal, ranged from 82–104%.     

MAP 4: occurrence in mouse tissues

A polyclonal antiserum to a microtubule-associated protein (MAP) from mouse neuroblastoma cells (MAP 4) was used to examine the distribution of this protein in mouse tissues. Immunoblots of neuroblastoma cell microtubule protein preparations demonstrated that the antiserum reacted with a triplet of proteins at 215,000-240,000 mol wt. Antibodies affinity purified from any of the bands showed cross- reaction with the other bands, indicating these polypeptides were all immunologically related. Antibodies specific to MAP 4 decorated microtubules in cultured murine cells fixed with glutaraldehyde, and diffuse staining was seen following treatment of cells with nocodazole. The antiserum reacted with MAP 4 in extracts of brain, heart, liver, and lung from adult mouse; the triplet in brain was more closely spaced than in the other tissues or neuroblastoma cells. In kidney, spleen, and stomach, only a single band (band 4) was labeled; this band was immunologically related to the triplet and was also present in all tissues positive for the triplet. Skeletal muscle, sperm, and peripheral blood contained no reactive polypeptides. After taxol- induced polymerization, the MAP 4 triplet was preferentially associated with the microtubule pellet whereas band 4 remained in the supernatant. These data indicate that there is tissue specificity in the distribution of MAP 4, and that some tissues contain a polypeptide related to MAP 4 (band 4) that does not bind to microtubules in vitro.     

On the occurrence of the Weasel,Mustela nivalis,in Turkey

Abstract

It was shown that the Weasel is distributed over the whole of Anatolia The species’ considerable size, the occasional occurrence of a white winter coat and the existence of two types of Weasels (nivalis type and minuta type) in Turkey have often lead to the wrong assumption that the Stoat (M. erminea) also occurs in Turkey.     

On the occurrence and status of the Chameleon,Chamaeleo chamaeleon,in Turkey

Abstract

The main distribution area of the Chameleon in Turkey is the Aegean and the Mediterranean regions, however, records are also available from the Marmara region and from southeast Anatolia.     

On the occurrence of Microsporum persicolor in Montreal,Canada

A case of Microsporum persicolor skin infection in a casual employee of a veterinary clinic in Montreal, Quebec, Canada, is reported. A survey of 80 wild rodents in the Montreal area resulted in the isolation of M. persicolor from two voles (Clethrionomys gapperi) and one deer mouse (Peromyscus maniculatus). One of the voles, heavily infested with parasites including ticks, had obvious lesions on the nose. This is the first report of M. persicolor in rodents in North America.