Somatic deletion and redistribution of telomeric heterochromatin in the genus Secale and in Triticale

C-banding analysis of populations of Secale kuprijanovii L., S. cereale L., and x Triticosecale Wittmack established that Secale chromosomes that were modified by the loss of a telomeric C-band arose spontaneously by breakage in somatic tissue and could be stabilized and maintained over at least two generations. In S. cereale approximately double-sized C-bands were seen on every arm that originally contained a C-band except 1RS, 2RS, 3RS, and 7RS. One plant was homomorphic for an amplified band on 3RL which was stable over two generations. In the tetraploid triticale analyzed, an amplified telomeric C-band was found on 5RS and was stable in the homomorphic condition for two generations. Even though Secale chromosomes with deleted or amplified telomeric C-bands can arise spontaneously in the somatic and germ tissue of Secale species and triticale, they are not common. The conditions required for their formation and stabilization within a population are not known.     

The amino acid metabolism of the developing sea urchin egg

The amino acid composition of the sea urchin egg in different developmental stages has been studied. In early development the changes in amino acid composition are relatively small. Clear changes in the content of most amino acids begin to occur in mesenchyme blastula stage or during gastrulation. Glutamine and the peptide containing fraction of tungstic acid extracts show greater quantitative changes than any of the other amino acids or fractions studied. Li treatment, which checks ectoderm-formation and favours entoderm-development also interferes on the amino acid level. The present results have been discussed in relation to other results from experimental, cytological and enzymic studies. An attempt to synthesize all these findings has been made.     

Pharmacological control of muscular activity in the sea urchin larva. III. Role of cyclic nucleotides.

1. The muscular activity of the sea urchin pluteus is strongly affected by dibutyryl-c-AMP, in a stimulatory or inhibitory manner depending on the concentration, the time of exposure, and the spontaneous level of activity. 2. Dibutyryl-c-GMP, like muscarinic agents and the guanylate-cyclase activators biotin and nitrite, keeps the activity low. 3. It is suggested that the effects of muscarinic agents is mediated by c-GMP, the effects of certain monoamines by c-AMP. 4. The two cyclic nucleotides appear to control the cellular influx of Ca2+ in opposite directions. They therefore interfere with the stimulatory and paralytic effects of nicotinic agents.     

Development of PCR-based codominant markers flanking the Alt3 gene in rye.

Aluminum (Al) toxicity is considered to be a major problem for crop growth and production on acid soils. The ability of crops to overcome Al toxicity varies among crop species and cultivars. Rye (Secale cereale L.) is the most Al-tolerant species among the Triticeae. Our previous study showed that Al tolerance in a rye F6 recombinant inbred line (RIL) population was controlled by a single gene designated as the aluminum tolerance (Alt3) gene on chromosome 4RL. Based on the DNA sequence of a rice (Oryza sativa L.) BAC clone suspected to be syntenic to the Alt3 gene region, we developed two PCR-based codominant markers flanking the gene. These two markers, a sequence-tagged site (STS) marker and a cleaved amplified polymorphic sequence (CAPS) marker, each flanked the Alt3 gene at an approximate distance of 0.4 cM and can be used to facilitate high-resolution mapping of the gene. The markers might also be used for marker-assisted selection in rye or wheat (Triticum aestivum L.) breeding programs to obtain Al-tolerant lines and (or) cultivars.     

The cytologic criteria of malignancy

Cytology and cell biology are two separate fields that share a focus on cancer. Cancer is still diagnosed based on morphology, and surprisingly little is known about the molecular basis of the defining structural features. Cytology uses the smallest possible biopsy for diagnosis by reducing morphologic “criteria of malignancy” to the smallest scale. To begin to develop common ground, members of the American Society of Cytopathology Cell Biology Liaison Working Group classify some of the “criteria of malignancy” and review their relation to current cell biology concepts. The criteria of malignancy are extremely varied, apparently reflecting many different pathophysiologies in specific microenvironments. Criteria in Group 1 comprise tissue‐level alterations that appear to relate to resistance to anoikis, alterations in cell adhesion molecules, and loss of apical–basal polarity. Criteria in Group 2 reflect genetic instability, including chromosomal and possibly epigenetic instability. Criteria in Groups 3 are subcellular structural changes involving cytoplasmic components, nuclear lamina, chromatin and nucleoli that cannot be accounted for by genetic instability. Some distinct criteria in Group 3 are known to be induced by cancer genes, but their precise structural basis remains obscure. The criteria of malignancy are not closely related to the histogenetic classification of cancers, and they appear to provide an alternative, biologically relevant framework for establishing common ground between cytologists and cell biologists. To understand the criteria of malignancy at a molecular level would improve diagnosis, and likely point to novel cell physiologies that are not encompassed by current cell biology concepts. J. Cell. Biochem. 110: 795–811, 2010. © 2010 Wiley‐Liss, Inc.     

Pharmacological control of muscular activity in the sea urchin larva--IV. Effects of monoamines and adenosine.

1. The muscular activity of the sea urchin pluteus is affected by catecholamines. alpha-Agonists in high concentrations bring about a strong, temporary, stimulation. 2. The stimulation by beta-agonists tends to be masked by different mechanisms. 3. Serotonin brings about a strong stimulation of long duration, even at 10(-7) M. It reactivates larvae where the activity has declined after exposure to catecholamines. A dopamine-effect at 10(-5)-5 x 10(-6) M is similar to that of serotonin. The effect of adenosine is similar to that of dc-c-AMP. 4. The action of the alpha- and beta-agonists and adenosine appears to involve an increased respectively excessive Ca2(+)-influx, directly or indirectly mediated by c-AMP. 5. It is suggested that a strong Ca2(+)-influx induces an outflux of K+ leading to hyperpolarization. Serotonin may decrease the K(+)-outflux.