Chlorophyll-protein and polypeptide composition of Mn-deficient sugar beet thylakoids

The chlorophyll-protein and polypeptide composition of manganese deficient and control sugar beet thylakoids was examined using three different detergent-electrophoresis systems. On a per chlorophyll basis, manganese deficiency reduced the amounts of CPa complex (separated by sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis), and CP 47 and CP 43 complexes (separated by octylglucoside/SDS-polyacrylamide gel electrophoresis) without decreasing the amounts of light harvesting complexes. Lithium dodecylsulfate/Triton X-100 polyacrylamide gel electrophoresis showed that manganese deficiency decreased several thylakoid polypeptides, including a chlorophyll b containing 30 kilodalton chlorophyll-protein complex, but did not decrease the amounts of 28 and 29 kilodalton light-harvesting chlorophyll b-containing polypeptides.     

Infertility associated with two accessory bisatellited chromosomes

Summary Two extra bisatellited chromosome identified as inv dup (15) (pterq11.2::q11.2pter) were found in an oligoasthenospermic male. Analysis of Ag-staining in the proband and in one fertile brother with a normal karyotype revealed that nucleolar organizer region (NOR) activity was significantly increased in the patient. The frequency of satellite associations was also significantly higher in the index case, but no correlation was found between NOR activity and acrocentric associations. These results suggest that extra NOR activity and the elevated frequency of satellite associations could predispose to gametogenic impairment.     

Chromosome pairing in female and male diploid and polyploid anurans (Amphibia) from South America

Chromosome pairing in females and males of diploid (2n = 22) and tetraploid (2n = 44) Odontophrynus americanus and diploid Ceratophrys cranwelli (2n = 26) and tetraploid C. ornata (2n = 104) showed that diploid females formed more chiasmata per paired arm than diploid males and polyploids of both sexes. There was a reduction in the level of recombination in female polyploids by forming multivalents with terminal chiasmata. The reduction reflected a change in the genetic control of pairing in females after polyploidization.     

Photoperiodic variations in plasma concentration of testosterone in the rabbit

The photoperiodic variations of testosterone plasmatic levels in male rabbits have been studied. The animals were subjected to the influence of three circadian rhythms: 12/12, 14/10 and 10/14 h of light/darkness. The hormone assay was carried out using an enzymeimmunoassay method (Competitive ELISA). Blood samples were of two different types: seriated and non-seriated, to find if these might be any differences in the results. It is concluded that testosterone plasmatic levels are within physiologic values (0.3-10.0 ng/ml), although differences depending on the light/darkness cycle and on the type of blood extraction are remarkable; for this reason the selection of the circadian rhythm will depend on the experimentation that is to be carried out.     

Fine needle aspiration of peripheral neuroepithelioma of soft tissues.

Peripheral neuroepithelioma of soft tissue is a malignant primitive neuroectodermal tumor that appears both in children and adults and usually has a poor outcome. Fine needle aspiration on two patients with tumors in the lower limbs showed small round cells with unipolar processes and a tendency to form Homer-Wright rosettes. The cells had a round to oval nucleus with fine chromatin, up to four small, conspicuous nucleoli and vacuolated, periodic acid-Schiff-positive cytoplasm. The diagnosis was supported by electron microscopic study of the aspirate, which showed features of neuroblastic differentiation (i.e., neurosecretory granules), and by histologic, immunohistochemical and cytogenetic study of the resected tumors.     

Effect of Quin-2 on 45Ca2+ uptake mediated by Na+i/Ca2+o exchange and 45Ca2+ efflux in rat brain synaptosomes: a requirement for [Ca2+]i

The Na+/Ca2+ exchanger of squid axons, barnacle muscle and sarcolemma requires micromolar intracellular calcium for activation in the Na+i/Ca2+o exchange mode ('reverse' Na+/Ca2+ exchange). The requirement for [Ca2+]i has been demonstrated with the use of intracellular calcium buffers, such as Quin-2, to inhibit Na+i/Ca2+o exchange. However, the inhibition of Na+i/Ca2+o exchange in mammalian nerve terminals loaded with Quin-2 has not been observed [7], suggesting a lower sensitivity to low [Ca2+]i for this system. In contrast, the results reported herein indicate that 45Ca2+ uptake in synaptosomes through Na+i/Ca2+o exchange is inhibited by Quin-2 much in the same way as it is in the squid, provided that synaptosomes are preincubated in low Ca2+ medium to avoid saturation of Quin-2. Under these conditions, 45Ca2+ efflux via Ca2+i/Ca2+o exchange is also inhibited. Our results indicate that the Na+i/Ca2+o and Ca2+i/Ca2+o modes of the Na+/Ca2+ exchanger from rat brain synaptosomes require intracellular calcium for activation. However, because no clear relationship between the observed [Ca2+]i values and the inhibition of Na+i/Ca2+o exchange has been found, it is suggested that localised submembrane calcium concentrations not detected by the [Ca2+]i probe might regulate the exchanger.