Patterns of Sleeping Site and Sleeping Tree Selection by Black-and-Gold Howler Monkeys (Alouatta caraya) in Northern Argentina

International Journal of Primatology - The selection of sleeping sites and sleeping trees in nonhuman primates is related to social and ecological factors. We investigate the role of body...     

Minimally-invasive Technique for Injection into Rat Optic Nerve

The rat optic nerve is a useful model for stem cell regeneration research. Direct injection into the rat optic nerve allows delivery into the central nervous system in a minimally-invasive surgery without bone removal. This technique describes an approach to visualization and direct injection of the optic nerve following minor fascial dissection from the orbital ridge, using a conjunctival traction suture to gently pull the eye down and out. Representative examples of an injected optic nerve show successful injection of dyed beads.     

Volumetric and golgi studies of the corpus geniculatum laterale pars dorsalis of Alticola stoliczkanus barakshin and Alticola argentatus semicanus

The dorsal lateral geniculate bodies (dLGB) in Alticola stoliczkanus barakshin, the Gobi-Altai-Mountain vole, and in Alticola argentatus semicanus, the silver grey mountain vole, and investigated using the nissl- and the golgi method. The geniculo-cortico-relay neurons (GCR neurons) of both species have 5 primary dendrites (D1), a dendritic field of about 100 micron, about 17 free dendritic distal parts (FDE), 10 branching points (VZP) and a average of the perikaryon of 10 micron. All tufted neurons are small and topographically distinctly localised. The dLGB's volume of Alticola stoczkanus, barakshin is 0.16 mm3, the dLGB's volume of Alticola argentatus semicanus is 0.23 mm3.     

Ferricrocin functions as the main intracellular iron-storage compound in mycelia ofNeurospora crassa

Summary Neurospora crassa produces several structurally distinct siderophores: coprogen, ferricrocin, ferrichrome C and some minor unknown compounds. Under conditions of iron starvation, desferricoprogen is the major extracellular siderophore whereas desferriferricrocin and desferriferrichrome C are predominantly found intracellularly. Mössbauer spectroscopic analyses revealed that coprogen-bound iron is rapidly released after uptake in mycelia of the wild-typeN.crassa 74A. The major intracellular target of iron distribution is desferriferricrocin. No ferritin-like iron pools could be detected. Ferricrocin functions as the main intracellular iron-storage peptide in mycelia ofN. crassa. After uptake of ferricrocin in both the wild-typeN. crassa 74A and the siderophore-free mutantN. crassa arg-5 ota aga, surprisingly little metabolization (11%) could be observed. Since ferricrocin is the main iron-storage compound in spores ofN. crassa, we suggest that ferricrocin is stored in mycelia for inclusion into conidiospores.     

Isolation and identification of the principal siderophore of the plant pathogenic fungusBotrytis cinerea

Summary The plant pathogenic hyphomyceteBotrytis cinerea has been shown to produce several trihydroxamate siderophores under conditions of low-iron stress. The total siderophores amounted to approximately 30 mg/l culture filtrate after 5 days of incubation in an asparagine/salt/glucose medium. Thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) on a reversed phase indicated that ferrirhodin is the predominant siderophore of this fungus. Chemical characterization of the principal siderophore by fast-atom-bombardment (FAB) mass spectrometry, nuclear magnetic resonance (¹H-NMR,¹³C-NMR) and comparison with a reference revealed the identity with ferrirhodin. NMR studies performed on desferrirhodin (desferrirhodin) in dimethylsulfoxide and water revealed the existence of two conformers in D₂O resulting from acis-trans isomerization of the hydroxamic acid groups. Comparative iron-uptake studies showed the following order of uptake inB. cinerea: ferrichrysin (100%), ferrirubin (57%), ferrirhodin (45%), hexahydroferrirhodin (45%), coprogen 6%. Concentration-dependent uptake of ferrirhodin resulted in saturation kinetics only in the low concentration range of 0–30 M (K _m = 2.5 M,V _max = 80 pmol min^–1 mg(^–1). A non-saturable, linear uptake was observed in the high concentration range of 30–80 M. The low concentration range appears to be the physiologically significant range, where siderophore-mediated iron transport inB. cinerea occurs.     

Free bone graft reconstruction of irradiated facial tissue: experimental effects of basic fibroblast growth factor stimulation

A study was undertaken to evaluate the potential utility of basic fibroblast growth factor in the induction of angiogenesis and osseous healing in bone previously exposed to high doses of irradiation. Thirty New Zealand rabbits were evaluated by introducing basic fibroblast growth factor into irradiated mandibular resection sites either prior to or simultaneous with reconstruction by corticocancellous autografts harvested from the ilium. The fate of the free bone grafts was then evaluated at 90 days postoperatively by microangiographic, histologic, and fluorochrome bone-labeling techniques. Sequestration, necrosis, and failure to heal to recipient osseous margins was observed both clinically and histologically in all nontreated irradiated graft sites as well as those receiving simultaneous angiogenic stimulation at the time of graft placement. No fluorescent activity was seen in these graft groups. In the recipient sites pretreated with basic fibroblast growth factor prior to placement of the graft, healing and reestablishment of mandibular contour occurred in nearly 50 percent of the animals. Active bone formation was evident at cortical margins adjacent to the recipient sites but was absent in the more central cancellous regions of the grafts.     

Molecular recognition of siderophores in fungi: role of iron-surrounding N-acyl residues and the peptide backbone during membrane transport in Neurospora crassa.

Recognition of ferric siderophores in Neurospora crassa was found to depend on the number and kind of N-acyl residues that surrounded the iron coordination center. In the coprogen series, uptake decreased in the order of coprogen, neocoprogen I, and neocoprogen II, indicating that gradual replacement of the N-transanhydromevalonyl groups by N-acetyl groups had an adverse effect on uptake. The reverse effect was observed in the ferrichrome series, where uptake decreased in the order of ferrichrysin, asperchrome D1, asperchrome B1, and ferrirubin. Configuration of the anhydromevalonyl group (cis or trans) in ferrichromes was also an important determinant in the recognition process. On the basis of uptake and inhibition studies, it is proposed that in ferrichromes part of the molecule (iron configuration and the N-acyl groups) is responsible for binding, whereas another (cyclic peptide ring) is involved in the subsequent process of transport.     

Metabolic products of microorganisms

1. The total nitrogen content of spores of Penicillium notatum increased during swelling and reached a maximum before germ-tubes were formed. It subsequently decreased during germ-tube formation until a constant value in hyphae was reached.
2. An increase in the protein content of the spores was found during swelling, followed by a decrease when germ-tubes were formed. After germination, the protein content increased again to a constant level in hyphae.
3. The content of total lipids steadily decreased during swelling of spores. It reached a minimum value in germinating spores, followed by a net accumulation during hyphal growth. Similar changes occurred in free lipids, phospholipids and the acetone-soluble lipids but not in bound lipids.
4. After an initial decrease during swelling, no further change took place in the neutral carbohydrates content of the spores at the time of germ-tube formation. An accumulation of neutral carbohydrates occurred during late hyphal extension.
5. The nucleic acid content increased sharply during swelling, and reached the highest value in swollen spores just prior to the initiation of germ-tube formation. Afterwards, its content steadily decreased during germ-tube formation and hyphae elongation.