STY1 and STY2 promote the formation of apical tissues during Arabidopsis gynoecium development

Gynoecium ontogenesis in Arabidopsis is accomplished by the co-ordinated activity of genes that control patterning and the regional differentiation of tissues, and ultimately results in the formation of a basal ovary, a short style and an apical stigma. A transposon insertion in the STYLISH1 (STY1) gene results in gynoecia with aberrant style morphology, while an insertion mutation in the closely related STYLISH2 (STY2) gene has no visible effect on gynoecium development. However, sty1-1 sty2-1 double mutant plants exhibit an enhanced sty1-1 mutant phenotype and are characterized by a further reduction in the amount of stylar and stigmatic tissues and decreased proliferation of stylar xylem. These data imply that STY1 and STY2 are partially redundant and that both genes promote style and stigma formation and influence vascular development during Arabidopsis gynoecium development. Consistently, STY1 and STY2 are expressed in the apical parts of the developing gynoecium and ectopic expression of either STY1 or STY2 driven by the CaMV 35S promoter is sufficient to transform valve cells into style cells. STY1::GUS and STY2::GUS activity is detected in many other organs as well as the gynoecium, suggesting that STY1 and STY2 may have additional functions. This is supported by the sty1-1 sty2-1 double mutants producing rosette and cauline leaves with a higher degree of serration than wild-type leaves. STY1 and STY2 are members of a small gene family, and encode proteins with a RING finger-like motif. Double mutant analyses indicate that STY1 genetically interacts with SPATULA and possibly also with CRABS CLAW.     

Platelet ionic calcium and serum total calcium in essential hypertension

A total of 44 cases comprising hypertensive (31) and normotensive group (13) were studied. Serum total calcium concentrations remained unaltered in hypertensives. Platelet cytosolic calcium in hypertensive group was significantly higher as compared to the normotensive controls. Platelet cytosolic calcium correlated with systolic and diastolic blood pressure and mean arterial pressure significantly.     

The role of ionic calcium in the gravitropic response of a creeping chrysanthemum cultivar

The stem of the creeping Chrysanthemum morifolium Ramat. cultivar ‘Yuhuajinhua’ responds to a gravitational stimulus by bending. Most of the calcium ion (Ca²⁺) present in the stem cells was concentrated in the cell walls, intercellular space, and vacuoles, with very little in the cytoplasm. An investigation of the effects of supplying exogenous Ca²⁺ or the Ca²⁺ chelator EGTA on the creeping habit and the level of endogenous IAA showed that, for at least 60 min after gravistimulation was initiated, the level of Ca²⁺ present in the epidermis cell walls on the lower side of the stem was maintained at a higher level than in those on the upper side. In the endodermis cells, most of the Ca²⁺ was located in the intercellular space, cell walls, and throughout the vacuole, with only little within the cytoplasm. Endodermis cell Ca²⁺ responded rapidly (within 5 min) to gravistimulation. The level of Ca²⁺ continued to increase within the cytoplasm for at least 30 min into the period of gravistimulation. Exogenously applied calcium chloride (CaCl₂) accentuated gravity-induced bending and the IAA concentration differed between the upper and the lower sides of the gravistimulated bent stem, whereas EGTA decreased these effects. Ca²⁺ appears to play an important role in the gravitropism of the ‘Yuhuajinhua’ creeping stem, not only by changing its distribution in the epidermis cell walls and the endodermis cytoplasm, but also by regulating IAA difference between the upper and lower sides of the creeping stem.     

The distribution of collagenase in normal rat tissues.

A rabbit monospecific anti-rat uterus collagenase antibody has been used to study the distribution of collagenase in normal rat tissues by immunohistochemical methods. Indirect staining was performed with fluorescein-conjugated goat anti-rabbit immunoglobulin G antibody. The organs studied were brain, lung, myocardium, liver, spleen, kidney, adrenal, testes, uterus, xiphoid cartilage, tail tendon, skeletal (triceps) muscle and skin. Collagenase is widely present throughout the connective tissue structures in all organs examined. The enzyme is apparently bound to collagen fibers, reticulum fibers and basement membranes. The results suggest that control of collagenase activity depends on factors other than the presence of the enzyme in tissues.     

The histochemical distribution of aniline hydroxylase in rat tissues

Synopsis The histochemical technique of Gangolli & Wright (1971) was used to detect aniline hydroxylase activity in a number of rat tissues. A high degree of activity was found in the adrenals (fasciculata and reticularis zones), the cortical tubules of the kidney, the epithelium of the small intestine, cardiac and red striated muscle and the corpus luteum. Less activity was found in the placenta, the endometrium in pregnancy and the epithelium of the bronchi and large intestine. Weak activity was present in the anterior pituitary gland, smooth muscle of the intestine, uterus and bladder, skin and bladder epithelium and white striated muscle. These was no activity in the thyroid and parathyroid, lymphoid tissue and endometrium. In all tissues the enzyme activity was denoted by a brownish deposit in the form of discrete small granules. The staining reaction was totally abolished when tissues were incubated in an atmosphere of a mixture of carbon monoxide and oxygen (8020 v/v), or in nitrogen, or by the omission of aniline from the incubation medium. Although it is not certain whether aniline hydroxylase activity in extrahepatic tissues has the same connotation and significance as microsomal hepatic aniline hydroxylase, its successful inhibition by carbon monoxide and nitrogen in a wide variety of tissues indicates that the histochemical demonstration of this enzyme may merit consideration in the study of chemically induced cellular damage in a variety of organs.     

The distribution of ferritin subunit types in porcine tissues

Ferritin was isolated from porcine heart, liver and spleen. Reversed phase high performance liquid chromatography of the ferritin subunits yielded three chromatographic fractions. The relative proportions of the three chromatographic fractions were different for each tissue ferritin. These results support the model which proposes a combination of (at least) two subunit types as the basis for the existence of isoferritins.