Sociality and individual fitness in yellow-bellied marmots: insights from a long-term study (1962–2001)

Theoretical and empirical studies suggest that the age of first reproduction (the age at which reproduction begins) can have a substantial influence on population dynamics and individual fitness. Using complete survival and reproductive histories of 428 female yellow-bellied marmots (Marmota flaviventris) from a 40-year study (1962-2001), we investigated causes and fitness consequences of delayed maturity. Most females (86%) died without reproducing. The age of first reproduction of females that survived to reproduce at least once (n=60) ranged from 2 to 6 years. Females maturing later did not have a larger lifetime number of successful reproductive events or offspring production, nor did they experience improved survival. Females reproducing earlier had a higher fitness than those that delayed maturity. These results suggest that the net cost of early maturity was less than fitness benefits associated with early onset of reproduction, and that age of first reproduction in our study population is under substantial directional selection favoring early maturity. We conclude that female yellow-bellied marmots delay onset of reproduction not because of fitness benefits of foregoing reproduction at an earlier age, but due to the social suppression of reproduction by older, reproductive females, which enhances their own fitness to the detriment of the fitness of young females. Our results indicate that female yellow-bellied marmots that survive to reproduce may act to increase their own direct fitness, and that social suppression of reproduction of young females is a part of that strategy.     

The Effect of Pseudomonas fluorescens and Fusarium oxysporum f.sp. cubense on Induction of Defense Enzymes and Phenolics in Banana

The effect of Pseudomonas fluorescens treatment and Fusarium oxysporum f. sp. cubense inoculation on induction of phenylalanine ammonia-lyase (PAL), peroxidase (POX), chitinase, -1,3-glucanase and accumulation of phenolics in banana (Musa sp.) was studied. When banana roots were treated with P. fluorescens strain Pf10, a two-fold increase in phenolic content in leaf tissues was recorded 3 – 6 d after treatment. Challenge inoculation with F. oxysporum, the wilt pathogen, steeply increased the phenolic content in P. fluorescens-treated banana plants. Significant increase in POX activity was detected 6 – 9 d after P. fluorescens treatment. PAL, chitinase and -1,3-glucanase activities increased significantly from 3 d after P. fluorescens treatment and reached the maximum 6 d after treatment. Challenge inoculation with F. oxysporum further increased the enzyme activities. These results suggest that the enhanced activities of defense enzymes and elevated content of phenolics may contribute to bioprotection of banana plants against F. oxysporum.     

Mechanisms of induction of germination of Bacillus subtilis spores by high pressure

Spores of Bacillus subtilis lacking all germinant receptors germinate >500-fold slower than wild-type spores in nutrients and were not induced to germinate by a pressure of 100 MPa. However, a pressure of 550 MPa induced germination of spores lacking all germinant receptors as well as of receptorless spores lacking either of the two lytic enzymes essential for cortex hydrolysis during germination. Complete germination of spores either lacking both cortex-lytic enzymes or with a cortex not attacked by these enzymes was not induced by a pressure of 550 MPa, but treatment of these mutant spores with this pressure caused the release of dipicolinic acid. These data suggest the following conclusions: (i) a pressure of 100 MPa induces spore germination by activating the germinant receptors; and (ii) a pressure of 550 MPa opens channels for release of dipicolinic acid from the spore core, which leads to the later steps in spore germination.     

Differential action of iodine on mitochondria from human tumoral- and extra-tumoral tissue in inducing the release of apoptogenic proteins

Iodide is actively concentrated in the thyroid gland for thyroid hormone biosynthesis. Excess iodine has been observed to induce apoptosis in thyrocytes and mammary cells. The mechanism of iodine induced apoptosis is poorly understood. Among various cell organelles, mitochondria is known to provide conducive environment for the organification of iodine, i.e. iodination of different proteins. Mitochondria also play a central role in execution of apoptosis. To study the role of mitochondria in iodine induced apoptosis, we investigated the direct interaction of iodine and human breast mitochondria vis-a-vis its role in the initiation of apoptosis in vitro. We observed that mitochondria isolated from the tumor (TT) and extra-tumoral tissue (ET) of human breast display significant uptake of iodine. Mitochondrial proteins were observed to be predominantly iodinated in ET but not in TT mitochondria. Treatment with iodine showed an increase in mitochondrial permeability transition of TT and decrease in ET. Iodine induced released factor(s) other than cytochrome c from tumor mitochondria initiate(s) apoptosis in vitro, while those from ET mitochondria were non-apoptogenic in nature. To our knowledge, this is first report demonstrating that iodine acts differentially on mitochondria of tumor and extratumoral origin to release apoptogenic proteins from TT and has a protective effect on ET.     

The Chediak-Higashi protein interacts with SNARE complex and signal transduction proteins

BACKGROUND:Chediak-Higashi syndrome (CHS) is an inherited immunodeficiency disease characterized by giant lysosomes and impaired leukocyte degranulation. CHS results from mutations in the lysosomal trafficking regulator (LYST) gene, which encodes a 425-kD cytoplasmic protein of unknown function. The goal of this study was to identify proteins that interact with LYST as a first step in understanding how LYST modulates lysosomal exocytosis. MATERIALS AND METHODS: Fourteen cDNA fragments, covering the entire coding domain of LYST, were used as baits to screen five human cDNA libraries by a yeast two-hybrid method, modified to allow screening in the activation and the binding domain, three selectable markers, and more stringent confirmation procedures. Five of the interactions were confirmed by an in vitro binding assay. RESULTS: Twenty-one proteins that interact with LYST were identified in yeast two-hybrid screens. Four interactions, confirmed directly, were with proteins important in vesicular transport and signal transduction (the SNARE-complex protein HRS, 14-3-3, and casein kinase II). CONCLUSIONS:On the basis of protein interactions, LYST appears to function as an adapter protein that may juxtapose proteins that mediate intracellular membrane fusion reactions. The pathologic manifestations observed in CHS patients and in mice with the homologous mutation beige suggest that understanding the role of LYST may be relevant to the treatment of not only CHS but also of diseases such as asthma, urticaria, and lupus, as well as to the molecular dissection of the CHS-associated cancer predisposition.     

Restriction fragment length polymorphism of rRNA operons for discrimination and intergenic spacer sequences for cataloging of Bacillus subtilis sub-groups

Restriction fragment length polymorphism of rRNA operons (RFLP) and 16S-23S rRNA intergenic region (ISR) sequences of Bacillus subtilis subsp. subtilis, B. subtilis subsp. spizizenii, and B. atrophaeus were compared. ISR sequences of the B. subtilis subspecies were extremely similar (W23 versus 168 rrn H, J, G,W; 96.8%; rrn D, E; 98.4%; rrnB; 97.9%) and, therefore, not useful for their differentiation. However, RFLP of rRNA operons of the B. subtilis subspecies were distinct in terms of numbers and organization within the genome (e.g. the 168 sub-group generally contained 8.3- and 8.0-kb fragments absent in the W23 sub-group). The more distantly related B. atrophaeus was distinct from both B. subtilis subspecies in terms of ISR sequence and rRNA operon number and organization. RFLP of rRNA operons discriminates the two sub-groups of Bacillus subtilis that are indistinguishable by ISR sequence. However, ISR sequence defines the relatedness of B. subtilis to other species (e.g. B. atrophaeus) within the genus Bacillus.     

An approach for cloning biosynthetic genes of 2-deoxystreptamine-containing aminocyclitol antibiotics: isolation of a biosynthetic gene cluster of tobramycin from Streptomyces tenebrarius

Genes homologous to 2-deoxystreptamine (DOS) biosynthetic genes were isolated from aminoglycoside producers, Micromonospora and Streptomyces spp., using PCR primers based on the core sequences of 2-deoxy-scyllo-inosose (DOI) synthase and L-glutamine: scyllo-inosose aminotransferase (GIA). Identities of 40-45% were observed for DOI synthases, and 65-75% were observed for GIAs. The gene cluster of tobramycin biosynthesis was isolated from the genomic library of Streptomyces tenebrarius using DOI synthase as a probe. Sequencing of 33.9 kb revealed 24 putative open reading frames including the tobramycin biosynthetic gene cluster (13.8 kb) and a transport protein. This cluster encodes proteins homologous to 2-deoxystreptamine biosynthetic enzymes, glycosyltransferase and other aminocyclitols biosynthetic enzymes. Sequence analysis revealed the evolution of DOI synthases from 3-dehydroquinate (DHQ) synthases in actinomycetes. DOI synthases and GIA are therefore useful for cloning biosynthetic genes of DOS-containing aminocyclitol antibiotics or for screening such metabolites producers.     

HAPPY mapping in a plant genome: reconstruction and analysis of a high-resolution physical map of a 1.9 Mbp region of Arabidopsis thaliana chromosome 4

HAPPY mapping is an in vitro approach for defining the order and spacing of DNA markers directly on native genomic DNA. This cloning-free technique is based on analysing the segregation of markers amplified from high molecular weight genomic DNA which has been broken randomly and 'segregated' by limiting dilution into subhaploid samples. It is a uniquely versatile tool, allowing for the construction of genome maps with flexible ranges and resolutions. Moreover, it is applicable to plant genomes, for which many of the techniques pioneered in animal genomes are inapplicable or inappropriate. We report here its demonstration in a plant genome by reconstructing the physical map of a 1.9 Mbp region around the FCA locus of Arabidopsis thaliana. The resulting map, spanning around 10% of chromosome 4, is in excellent agreement with the DNA sequence and has a mean marker spacing of 16 kbp. We argue that HAPPY maps of any required resolution can be made immediately and with relatively little effort for most plant species and, furthermore, that such maps can greatly aid the construction of regional or genome-wide physical maps.     

Effect of naloxone on GnRH-induced LH and FSH release in buffalo, Bubalus bubalis

The effect of naloxone on GnRH-induced LH and FSH release was measured in buffaloes in luteal phase of estrous cycle. Animals were administered intravenously, naloxone/saline (50 mg/injection) every 15 min for 3 hr followed by GnRH (100 micrograms). Peripheral plasma LH and FSH concentrations were measured in blood samples collected at 15 min intervals from 1 hr prior to beginning of naloxone/saline treatment up to 3 hr post GnRH administration and every 30 min for the subsequent 3.5 hr. Between the animals of Group I administered naloxone and those of Group II given saline, GnRH-induced peak LH and FSH concentrations, the total LH and FSH released in response to GnRH, and the time to peak LH and FSH concentrations were not significantly different. The results of the present study suggest the absence of a direct effect of naloxone on pituitary responsiveness to GnRH.