First direct evidence of hibernation in an eastern dwarf lemur species (Cheirogaleus crossleyi) from the high-altitude forest of Tsinjoarivo, central-eastern Madagascar

The nocturnal mouse and dwarf lemurs from Madagascar are known to express heterothermy. Whereas dwarf lemurs (Cheirogaleus) are obligate hibernators, mouse lemurs (Microcebus) can express a great range of heterothermic responses, including daily torpor, prolonged torpor or hibernation, depending on the species, population or individual. Although there is indirect evidence of heterothermy in a handful of mouse lemur species, direct physiological confirmation is currently limited to four: Microcebus berthae(dry forest), M. ravelobensis(dry forest), M. griseorufus(spiny forest), M. murinus(dry forest/littoral forest). We studied Goodman’s mouse lemurs (M. lehilahytsara) at the high-altitude rain forest of Tsinjoarivo, central-eastern Madagascar. We captured a total of 45 mouse lemurs during pre- and post-torpor seasons. We recorded body mass and measured tail base circumference, which was used as proxy for fattening. Moreover, using telemetry, we obtained sporadic skin temperature data from a mouse lemur female between March and June. From June 9 to 16, we performed more intensive data sampling and thereby confirmed the expression of prolonged torpor in this female, when skin temperatures consistently displayed values below 25°C for more than 24 h. We documented 3 torpor bouts, 2 of which were interrupted by naturally occurring arousals. Torpor bout duration ranged from approximately 47 to maximally about 69 h. We found similarities between the Goodman’s mouse lemur torpor profile and those known from other species, including the fact that only a portion of any mouse lemur population deposits fat stores and undergoes torpor in a given year. The variable expression of heterothermy in Goodman’s mouse lemurs contrasts with obligatory hibernation displayed by two sympatric species of dwarf lemurs, suggesting cheirogaleids use a range of metabolic strategies to cope with seasonality and cold environments.

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MtDNA and nDNA corroborate existence of sympatric dwarf lemur species at Tsinjoarivo, eastern Madagascar

Molecular Phylogenetics and Evolution ◽

10.1016/j.ympev.2010.03.004 ◽

2010 ◽

Vol 55 (3) ◽

pp. 833-845 ◽

Cited By ~ 20

Author(s):

Linn F. Groeneveld ◽

Marina B. Blanco ◽

Jean-Luc Raharison ◽

Vololonirina Rahalinarivo ◽

Rodin M. Rasoloarison ◽

...

Keyword(s):

Dwarf Lemur ◽

Lemur Species

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Contrast of Filament Bright Rims

International Astronomical Union Colloquium ◽

10.1017/s0252921100025628 ◽

1994 ◽

Vol 144 ◽

pp. 365-367

Author(s):

E. V. Kononovich ◽

O. B. Smirnova ◽

P. Heinzel ◽

P. Kotrč

Keyword(s):

High Altitude ◽

Line Profile ◽

Line Center ◽

Magnetic Structures ◽

The Mean

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.

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Clean Electron Microscope Substrate Films Used for Micrometeorite Collection and Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061847 ◽

1967 ◽

Vol 25 ◽

pp. 366-367

Author(s):

D. M. Davies ◽

R. Kemner ◽

E. F. Fullam

Keyword(s):

Thin Film ◽

Electron Microscope ◽

High Altitude ◽

Amyl Acetate ◽

Temperature Variations ◽

Film Forming ◽

Film Specimen ◽

Particulate Contaminants

All serious electron microscopists at one time or another have been concerned with the cleanliness and freedom from artifacts of thin film specimen support substrates. This is particularly important where there are relatively few particles of a sample to be found for study, as in the case of micrometeorite collections. For the deposition of such celestial garbage through the use of balloons, rockets, and aircraft, the thin film substrates must have not only all the attributes necessary for use in the electron microscope, but also be able to withstand rather wide temperature variations at high altitude, vibration and shock inherent in the collection vehicle's operation and occasionally an unscheduled violent landing.Nitrocellulose has been selected as a film forming material that meets these requirements yet lends itself to a relatively simple clean-up procedure to remove particulate contaminants. A 1% nitrocellulose solution is prepared by dissolving “Parlodion” in redistilled amyl acetate from which all moisture has been removed.

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The Immuno-Electron Microscopic Localization of the Mo-Fe Protein Component of Nitrogenase in Cells of Azotobacter Vinelandii

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073313 ◽

1973 ◽

Vol 31 ◽

pp. 574-575

Author(s):

J. T. Stasny ◽

R. C. Burns ◽

R. W. F. Hardy

Keyword(s):

Cellular Localization ◽

Direct Evidence ◽

Azotobacter Vinelandii ◽

Intracellular Localization ◽

Protein Component ◽

Electron Microscopic ◽

Thin Sections ◽

Fe Protein ◽

Intracytoplasmic Membranes

Structure-functlon studies of biological N2-fixation have correlated the presence of the enzyme nitrogenase with increased numbers of intracytoplasmic membranes in Azotobacter. However no direct evidence has been provided for the internal cellular localization of any nitrogenase. Recent advances concerned with the crystallizatiorTand the electron microscopic characterization of the Mo-Fe protein component of Azotobacter nitrogenase, prompted the use of this purified protein to obtain antibodies (Ab) to be conjugated to electron dense markers for the intracellular localization of the protein by electron microscopy. The present study describes the use of ferritin conjugated to goat antitMo-Fe protein immunoglobulin (IgG) and the observations following its topical application to thin sections of N2-grown Azotobacter.

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Structural similarity of ribosomes from E. coli and A. salina

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082078 ◽

1978 ◽

Vol 36 (2) ◽

pp. 242-243

Author(s):

M. Boublik ◽

R.M. Wydro ◽

W. Hellmann ◽

F. Jenkins

Keyword(s):

Ribosomal Proteins ◽

Direct Evidence ◽

Structural Similarity ◽

Carbon Support ◽

Artemia Salina ◽

Uranyl Acetate ◽

Biological Assays ◽

E Coli ◽

And Function ◽

Fine Carbon

Ribosomes are ribonucleoprotein particles necessary for processing the genetic information of mRNA into proteins. Analogy in composition and function of ribosomes from diverse species, established by biochemical and biological assays, implies their structural similarity. Direct evidence obtained by electron microscopy seems to be of increasing relevance in understanding the structure of ribosomes and the mechanism of their role in protein synthesis.The extent of the structural homology between prokaryotic and eukaryotic ribosomes has been studied on ribosomes of Escherichia coli (E.c.) and Artemia salina (A.s.). Despite the established differences in size and in the amount and proportion of ribosomal proteins and RNAs both types of ribosomes show an overall similarity. The monosomes (stained with 0.5% aqueous uranyl acetate and deposited on a fine carbon support) appear in the electron micrographs as round particles with a diameter of approximately 225Å for the 70S E.c. (Fig. 1) and 260Å for the 80S A.s. monosome (Fig. 2).

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Stress Relaxation and the Formation of Silicides in the Process of the Crystallization of NI-NB Films on SI

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100088804 ◽

1991 ◽

Vol 49 ◽

pp. 898-899

Author(s):

N. Rozhanski ◽

V. Lifshitz

Keyword(s):

Thin Films ◽

Stress Relaxation ◽

Integrated Circuits ◽

Direct Evidence ◽

Alloy Film ◽

Diffusion Barriers ◽

Effective Barrier

Thin films of amorphous Ni-Nb alloys are of interest since they can be used as diffusion barriers for integrated circuits on Si. A native SiO2 layer is an effective barrier for Ni diffusion but it deformation during the crystallization of the alloy film lead to the appearence of diffusion fluxes through it and the following formation of silicides. This study concerns the direct evidence of the action of stresses in the process of the crystallization of Ni-Nb films on Si and the structure of forming NiSi2 islands.

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Point and planar defects in the iron sulfide compounds Fe1-xS

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011221x ◽

1984 ◽

Vol 42 ◽

pp. 434-435

Author(s):

Thao A. Nguyen

Keyword(s):

Low Temperatures ◽

Direct Evidence ◽

Iron Sulfide ◽

Planar Defects ◽

Selective Area ◽

Vacancy Ordering ◽

Different Types ◽

Lattice Images ◽

The Subject ◽

Beam Lattice

It is well known that the large deviations from stoichiometry in iron sulfide compounds, Fe1-xS (0≤x≤0.125), are accommodated by iron vacancies which order and form superstructures at low temperatures. Although the ordering of the iron vacancies has been well established, the modes of vacancy ordering, hence superstructures, as a function of composition and temperature are still the subject of much controversy. This investigation gives direct evidence from many-beam lattice images of Fe1-xS that the 4C superstructure transforms into the 3C superstructure (Fig. 1) rather than the MC phase as previously suggested. Also observed are an intrinsic stacking fault in the sulfur sublattice and two different types of vacancy-ordering antiphase boundaries. Evidence from selective area optical diffractograms suggests that these planar defects complicate the diffraction pattern greatly.

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