Timing of Expression of a Gene in the Adult Drosophila Is Regulated by Mechanisms Independent of Temperature and Metabolic Rate

Abstract The examination of β-galactosidase (β-gal) expression in the third segment of the antenna of the 2216 enhancer trap line in Drosophila melanogaster reveals two distinct spatial and temporal regulatory patterns of expression during adult life. Type I expression is characterized by a decline in the level of β-gal expression with increasing age. Starting from a maximal level of expression at the time of adult emergence, there is a decrease in the number of cells that express β-gal so that by 40-50 days of adult life few cells express β-gal. Varying the ambient temperature and using hyperactivity mutants (Hyperkznetic1, Shaker5) demonstrates that the rate of this decline is independent of temperature and metabolic rate. Type II expression is distinctly different in spatial distribution and temporal regulation from the first pattern. Type II expression is restricted in the antenna to a small (<20–30) set of cells whose level of expression changes in a periodic manner with time. The regulation of this periodicity appears to be linked to ambient temperature.

Download Full-text

Histochemical and Morphometric Evaluation of Skeletal Muscle of Cachectic Sheep

Veterinary Pathology ◽

10.1177/030098588101800301 ◽

1981 ◽

Vol 18 (3) ◽

pp. 279-298 ◽

Cited By ~ 12

Author(s):

T. J. Hulland

Keyword(s):

Skeletal Muscle ◽

Muscle Fiber ◽

Succinic Dehydrogenase ◽

Adult Life ◽

Biological Behavior ◽

Type I ◽

Fiber Types ◽

Type Ii ◽

Atrophy And Hypertrophy ◽

Type I Fibers

Skeletal muscle of sheep was examined histochemically in an attempt to define muscle fiber populations capable of distinctive biological behavior. ATPase at alkaline and acid pH, NADH-TR, and succinic dehydrogenase showed at least 12 fiber types, but only three often enough to be considered biologically important muscle fiber populations. The proportions of the three major types altered during early life, but not perceptibly during adult life. Proportions of Type I and Type II fibers were different, sometimes significantly, from breed to breed. Histochemical techniques and morphometric analyses of fiber cross-sectional area were used to study muscle fiber changes in moderate to marked cachectic atrophy. Progressive reduction of gross muscle volume was attended by complex interrelationships between the two major muscle fiber types, including alternate episodes of atrophy and hypertrophy, resulting in marked inequality of mean fiber size between the fiber types. The patterns appeared to be different but characteristic for each muscle. The usual pattern of cachectic atrophy shows atrophy resistance of Type I fibers, but here a Type II-dominant atrophy also was seen. It is concluded that the large muscle fibers often seen in advanced cachectic atrophy are those Type I fibers that are more labile in both atrophy and hypertrophy than most.

Download Full-text

Fine-Structural Changes in a Lepidopteran Nervous System During Metamorphosis

Journal of Cell Science ◽

10.1242/jcs.14.2.369 ◽

1974 ◽

Vol 14 (2) ◽

pp. 369-387

Author(s):

BARBARA J. McLAUGHLIN

Keyword(s):

Tight Junctions ◽

Manduca Sexta ◽

Structural Changes ◽

Cell Layer ◽

Adult Emergence ◽

Cell Junctions ◽

Type I ◽

Type Ii ◽

Type Ii Cell ◽

I Cells

The fine structure of the metamorphosing abdominal nerve cord of Manduca sexta has been studied. In fifth instar larvae, the connectives are ensheathed by a complex, thickened neural lamella. The underlying perineurium at this stage consists of 2 layers. The outer layer consists of interdigitating type I cells which are attached to the overlying neural lamella by hemidesmosomes, and to each other by occasional gap and tight junctions which persist throughout development. They are attached by desmosomes to a thin underlying type II cell layer, which is joined by gap and tight junctions and which has desmosomal attachments with the underlying glial membranes. The larval axons are surrounded by multiple glial wrappings containing bundles of microtubules. During the first week after larval-pupal ecdysis, the neural lamella degenerates and is phagocytosed by invading haemocytes. The underlying perineurial I cells gradually become hypertrophied and vacuolated. At the same time the type II layer, which does not increase in size, appears to be composed of either one or two cells which form a continuous ‘bracelet’ around each connective. The cellular bracelet is joined at one or two places by extensive gap, tight and septate junctions, and gap junctions are also seen along its perineurial I and glial borders. The underlying axons are embedded in vast amounts of glial cytoplasm containing relatively few microtubules. During the second week after larval-pupal ecdysis, the neural lamella is reformed and the perineurium flattens again. Type I and II cell junctions remain as described in earlier stages. Before adult emergence, the axons are again wrapped by glial cells rich in microtubules.

Download Full-text

Diabetic nephropathy: a disease causing and complicated by hypertension

Clinical Chemistry ◽

10.1093/clinchem/37.10.1838 ◽

1991 ◽

Vol 37 (10) ◽

pp. 1838-1842 ◽

Cited By ~ 5

Author(s):

M W Steffes ◽

S M Mauer

Keyword(s):

Diabetes Mellitus ◽

Type Ii Diabetes ◽

Type I Diabetes ◽

Adult Life ◽

Type Ii Diabetes Mellitus ◽

Type I ◽

Type Ii ◽

Pima Indians ◽

Capillary Surface ◽

Glomerular Capillary

Abstract In examining the pathophysiology underlying the development of hypertension in diabetes mellitus, it is important to draw clear distinctions between Type I and Type II diabetes. In patients with Type I diabetes, with a peak onset of disease early in the second decade of life, hypertension clearly represents the sequelae to the development of substantial renal lesions, especially in the glomerulus. Thus the prevalence of hypertension in those patients without substantial glomerular lesions approximates the incidence of hypertension in the general population (approximately 4%). In patients with Type II diabetes mellitus and onset generally later in adult life, an increase in blood pressure can often be demonstrated early after or even before diagnosis of the disease (most readily demonstrated in the Pima Indians). Furthermore, clear familial tendencies towards the development of nephropathic complications of diabetes can be shown. In patients with Type I disease, the fall in glomerular filtration rate parallels the fall in glomerular capillary surface available for filtration. This reduction in the peripheral glomerular capillary surface correlates well with the expansion of the mesangium, strongly implicating the mesangial expansion in the demise in renal function. For both Type I and Type II diabetes mellitus, the increase in albuminuria may reflect an opening of large pores in the glomerular basement membrane, thereby allowing serum proteins to cross into the filtration space.

Download Full-text

Dlk1-Mediated Temporal Regulation of Notch Signaling Is Required for Differentiation of Alveolar Type II to Type I Cells during Repair

Cell Reports ◽

10.1016/j.celrep.2019.02.046 ◽

2019 ◽

Vol 26 (11) ◽

pp. 2942-2954.e5 ◽

Cited By ~ 19

Author(s):

Johanna Finn ◽

Kilian Sottoriva ◽

Kostandin V. Pajcini ◽

Jan K. Kitajewski ◽

Chang Chen ◽

...

Keyword(s):

Notch Signaling ◽

Alveolar Type ◽

Type I ◽

Type Ii ◽

Temporal Regulation ◽

Type I Cells ◽

I Cells

Download Full-text

Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067522 ◽

1970 ◽

Vol 28 ◽

pp. 106-107 ◽

Cited By ~ 1

Author(s):

Ronald S. Weinstein ◽

N. Scott McNutt

Keyword(s):

New Zealand ◽

General Hospital ◽

Massachusetts General Hospital ◽

Type I ◽

Type Ii ◽

Collaborative Effort ◽

Temperature And Pressure ◽

The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

Download Full-text

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111367 ◽

1984 ◽

Vol 42 ◽

pp. 250-251

Author(s):

G. D. Gagne ◽

M. F. Miller ◽

D. A. Peterson

Keyword(s):

Endoplasmic Reticulum ◽

Experimental Infection ◽

Uranyl Acetate ◽

Type I ◽

Cellular Injury ◽

Type Ii ◽

Tubular Structures ◽

Type Iii ◽

Type Iv ◽

Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

Download Full-text

Comparative surface and ultrastructural views of methylotrophic bacteria by TEM, STEM, SE, and freeze-etch electron microscopy.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128274 ◽

1987 ◽

Vol 45 ◽

pp. 792-793

Author(s):

T.A. Fassel ◽

M.J. Schaller ◽

M.E. Lidstrom ◽

C.C. Remsen

Keyword(s):

Cytoplasmic Membrane ◽

Structural Features ◽

Methylotrophic Bacteria ◽

Type I ◽

Type Ii ◽

Membrane Complex ◽

Oxidation Of Methane ◽

Methane Oxidizing Bacteria ◽

Wall Structures ◽

Methylomonas Albus

Methylotrophic bacteria play an Important role in the environment in the oxidation of methane and methanol. Extensive intracytoplasmic membranes (ICM) have been associated with the oxidation processes in methylotrophs and chemolithotrophic bacteria. Classification on the basis of ICM arrangement distinguishes 2 types of methylotrophs. Bundles or vesicular stacks of ICM located away from the cytoplasmic membrane and extending into the cytoplasm are present in Type I methylotrophs. In Type II methylotrophs, the ICM form pairs of peripheral membranes located parallel to the cytoplasmic membrane. Complex cell wall structures of tightly packed cup-shaped subunits have been described in strains of marine and freshwater phototrophic sulfur bacteria and several strains of methane oxidizing bacteria. We examined the ultrastructure of the methylotrophs with particular view of the ICM and surface structural features, between representatives of the Type I Methylomonas albus (BG8), and Type II Methylosinus trichosporium (OB-36).

Download Full-text