Quantitative assessment of morphological changes in lipid droplets and lipid-mito interactions with aging in brown adipose.

The physical characteristics of brown adipose tissue (BAT) are defined by the presence of multilocular lipid droplets (LDs) within the brown adipocytes and a high abundance of iron-containing mitochondria, which give it its characteristic color. Normal mitochondrial function is, in part, regulated by organelle-to-organelle contacts. For example, the contact sites that mediate mitochondria-LD interactions are thought to have various physiological roles, such as the synthesis and metabolism of lipids.

The MICOS Complex Regulates Mitochondrial Structure and Oxidative Stress During Age-Dependent Structural Deficits in the Kidney.

The kidney filters nutrient waste and bodily fluids from the bloodstream, in addition to secondary functions of metabolism and hormone secretion, requiring an astonishing amount of energy to maintain its functions. In kidney cells, mitochondria produce adenosine triphosphate (ATP) and help maintain kidney function. Due to aging, the efficiency of kidney functions begins to decrease.

Quantitative Assessment of Morphological Changes in Lipid Droplets and Lipid-Mito Interactions with Aging in Brown Adipose.

The physical characteristics of brown adipose tissue (BAT) are defined by the presence of multilocular lipid droplets (LD) within the brown adipocytes and a high abundance of iron-containing mitochondria, which give it its characteristic color. Normal mitochondrial function is, in part, regulated by organelle-to-organelle contacts. Particularly, the contact sites that mediate mitochondria-LD interactions are thought to have various physiological roles, such as the synthesis and metabolism of lipids.

3D Mitochondrial Structure in Aging Human Skeletal Muscle: Insights into MFN-2 Mediated Changes.

Age-related atrophy of skeletal muscle, is characterized by loss of mass, strength, endurance, and oxidative capacity during aging. Notably, bioenergetics and protein turnover studies have shown that mitochondria mediate this decline in function. Although exercise has been the only therapy to mitigate sarcopenia, the mechanisms that govern how exercise serves to promote healthy muscle aging are unclear.

Correction: Garza-Lopez et al. Protocols for Generating Surfaces and Measuring 3D Organelle Morphology Using Amira. 2022, , 65.

In the original publication [...

Systematic Transmission Electron Microscopy-Based Identification and 3D Reconstruction of Cellular Degradation Machinery.

Various intracellular degradation organelles, including autophagosomes, lysosomes, and endosomes, work in tandem to perform autophagy, which is crucial for cellular homeostasis. Altered autophagy contributes to the pathophysiology of various diseases, including cancers and metabolic diseases. This paper aims to describe an approach to reproducibly identify and distinguish subcellular structures involved in macroautophagy.

Protocols for Generating Surfaces and Measuring 3D Organelle Morphology Using Amira.

High-resolution 3D images of organelles are of paramount importance in cellular biology. Although light microscopy and transmission electron microscopy (TEM) have provided the standard for imaging cellular structures, they cannot provide 3D images. However, recent technological advances such as serial block-face scanning electron microscopy (SBF-SEM) and focused ion beam scanning electron microscopy (FIB-SEM) provide the tools to create 3D images for the ultrastructural analysis of organelles.

A Universal Approach to Analyzing Transmission Electron Microscopy with ImageJ.

Transmission electron microscopy (TEM) is widely used as an imaging modality to provide high-resolution details of subcellular components within cells and tissues. Mitochondria and endoplasmic reticulum (ER) are organelles of particular interest to those investigating metabolic disorders. A straightforward method for quantifying and characterizing particular aspects of these organelles would be a useful tool.

TMEM135 is a Novel Regulator of Mitochondrial Dynamics and Physiology with Implications for Human Health Conditions.

Transmembrane proteins (TMEMs) are integral proteins that span biological membranes. TMEMs function as cellular membrane gates by modifying their conformation to control the influx and efflux of signals and molecules. TMEMs also reside in and interact with the membranes of various intracellular organelles.

Network Architecture of Gap Junctional Coupling among Parallel Processing Channels in the Mammalian Retina.

Gap junctions are ubiquitous throughout the nervous system, mediating critical signal transmission and integration, as well as emergent network properties. In mammalian retina, gap junctions within the Aii amacrine cell-ON cone bipolar cell (CBC) network are essential for night vision, modulation of day vision, and contribute to visual impairment in retinal degenerations, yet neither the extended network topology nor its conservation is well established. Here, we map the network contribution of gap junctions using a high-resolution connectomics dataset of an adult female rabbit retina.

Multiple sclerosis: etiological mechanisms and future directions.

Multiple sclerosis (MS) is a complex human autoimmune-type disease with a predominantly unknown etiology. Immunologic destruction of myelin basic protein (MBP) throughout the nervous system is the major pathology of multiple sclerosis. This review will attempt to update new information about basic mechanisms and therapeutic management of the disease.

Circulating natural IgM antibodies and their corresponding human cord blood cell-derived Mabs specifically combat the Tat protein of HIV.

Objective: IgM antibodies reactive with each of two specifically defined sequences of HIV Tat protein have been identified in sera from both HIV(+) and normal (HIV(-)) humans. This study was designed to confirm that those antibodies are innate immune factors capable of restriction of specific mechanisms of HIV pathogenicity attributed to the Tat protein.

Materials And Methods: Antibody-secreting hybridomas were generated from human cord blood cells and processed for monoclonality.

The human uniqueness of HIV: innate immunity and the viral Tat protein.

We have previously reported, and confirm here, that the human innate system of natural antibodies includes two, each of which is reactive, presumably by happenstance, with a specific sequence of HIV Tat protein. Comparison of cohorts of HIV+ and normal (HIV-) sera indicate that, following a period of post-infection latency, the titers of those natural antibodies decline and other Tat reactive antibodies, as evidence of induced immune response, do not arise. That human-typical pattern of innate/adaptive reactivity with HIV Tat protein is shared by chimpanzees, but not by other mammals tested in this study, in which those natural antibodies are not present, and apparently induced Tat-reactive antibodies do arise.

Two human neonatal IgM antibodies encoded by different variable-region genes bind the same linear peptide: evidence for a stereotyped repertoire of epitope recognition.

Two monoclonal IgM Abs have been produced from lymphocytes isolated from two human umbilical cord bloods. These mAbs recognize a conformational epitope present in a CNBr digestion fraction of lactoferrin. Linear epitopes recognized by each mAb were selected from several phage display peptide libraries.

An innate natural antibody is reactive with a cryptic sequence of lactoferrin exposed on sperm head surface.

Lactoferrin (LF), an 80-kDa glycoprotein of ubiquitous occurrence in body fluids, is multifunctional and capable of assuming different configurations to serve those functions. The capacity of LF to undergo endocytosis and the recent demonstration of LF binding to sequence specific DNA indicate that a function or capability of LF, in addition to iron chelation, bacteriostasis, and receptor-specific lymphocyte binding, may be that of gene activation or silencing. The data of this report present a human physiological system, that of sperm entry into the oocyte in performance of fertilization in which, since LF is a component of the sperm protein coat, that capability could be expressed.

Innate natural antibodies. Primary roles indicated by specific epitopes.

Two members of a unique class of natural antibodies have been identified in all of a large cohort of sera from clinically normal humans of broad age distribution. By means of a series of 10-12 mer peptides the epitope for each of those antibodies was characterized with regard to amino acid identity and conformation. Similar epitope specificity was revealed for the IgM isotopes of cord blood and early post natal sera and for IgM and IgG of adult sera, suggesting that the class of natural antibodies represented by the two identified in this study includes those genomically coded for at their effector level of maturation in the B cells of the neonate.

Epitopes for natural antibodies of human immunodeficiency virus (HIV)-negative (normal) and HIV-positive sera are coincident with two key functional sequences of HIV Tat protein.

We have previously shown that IgM antibodies that react with human immunodeficiency virus (HIV) Tat, a regulatory protein essential for viral replication, are present in sera of all normal, HIV-negative individuals and deficient in sera of HIV-positive individuals at progressively greater frequency as diagnosis of AIDS nears. That IgM was designated as a set of natural antibodies, a repertoire of the normal humoral immune system believed to provide early defense against infectious invaders. In the prior study, by means of a series of synthetic peptides representing the amino acid sequence of HIV-1 Tat, one epitope for the IgM natural antibodies was defined within the cysteine-rich domain, shown in cell transfection studies to participate in Tat function.

Human immunodeficiency virus (HIV) Tat-reactive antibodies present in normal HIV-negative sera and depleted in HIV-positive sera. Identification of the epitope.

We have detected, in sera of normal human immunodeficiency virus (HIV)-free subjects, IgM antibodies reactive with the Tat protein of HIV in significant titers and at very high frequency, and, in HIV-positive sera, progressively lower titers as HIV pathogenesis ensues. Epitope analysis indicates that the Tat-reactive antibodies of both HIV-negative and HIV-positive sera are homologous, suggesting, therefore, that their decline in HIV-positive sera may represent attrition of a host defense factor. The identified epitope displays minimal homology with that previously defined for another set of IgM antibodies shown to be present in normal sera, deficient in HIV-positive sera, and postulated to be natural antibodies.

Caveats and suggestions for the ELISA.

This study identifies three categories of errors that may arise from faulty procedures utilized in the ELISA and offers suggestions for their recognition and avoidance. The first deals with the potential sources of 'background' values indicating that the practice of subtracting those values from the total OD measurements of the reactivity of a specific antigen-antibody system is not valid in all instances. A simple method of curve analysis has been devised for determining whether that correction is valid.

Identification of a low-affinity subset of protamine-reactive IgM antibodies present in normal, deficient in AIDS, sera: implications for HIV latency.

We demonstrate here that the protamine-reactive IgM antibodies previously shown to be present in normal adult sera include two subsets differing in binding affinity. The principal, high-affinity subset was detected in AIDS and ARC as well as normal sera. The secondary, low-affinity subset, however, was absent or markedly deficient in AIDS or ARC sera.

The electrocardiogram in chronic obstructive pulmonary disease.

The electrocardiogram is often abnormal in patients who have chronic obstructive pulmonary disease. The most frequent abnormalities are a rightward P-wave axis (greater than or equal to 70 degrees) and a rightward QRS axis (greater than or equal to 90 degrees). In addition, low voltage in the limb leads, an S1S2S3 pattern, poor R-wave progression, a posterior-superior terminal QRS vector or other changes may be present.

Protamine-reactive natural IgM antibodies in human sera. Characterization of the epitope demonstrates specificity of antigenic recognition; occurrence indicates obscurity of origin and function.

We have identified a set of natural IgM antibodies in human serum that are reactive with protamines, a class of low molecular weight basic nucleoproteins that are synthesized de novo in the postpubertal testis and are unique to sperm. Those antibodies were detected by ELISA in significant titer in all of 100 sera of normal adult males and females and in 26 of 28 sera of normal pediatrics aged 7 d to 2 yr. Commonality between the protamine-reactive IgM antibodies of pediatric and adult sera was established by the demonstration of similarity in antigen recognition and reaction kinetics.

Phosphorylation state of protamines 1 and 2 in human spermatids and spermatozoa.

The basic nuclear proteins of a fraction of elongating spermatids from human testes and of a fraction of motile spermatozoa from the ejaculate, separated by ion-exchange chromatography, were compared. Analysis by acetic acid-urea polyacrylamide gel electrophoresis (PAGE) showed that, in both fractions, four proteins of lower mobility were coeluted with protamine 1 by 23% guanidinium chloride (GuCl) while protamine 2 alone was eluted by 50% GuCl. Treatment with alkaline phosphatase identified those four proteins as phosphorylated protamines, and cyanogen bromide (CNBr) treatment of the dephosphorylated protamines distinguished them as variants of protamine 2 and not of protamine 1.

Reactivity of natural IgM antibodies with sperm head surface proteins. Use of an ELISA to characterize the reaction.

The data and system of analysis presented in this report have defined a subset of natural IgM antibodies in human sera that are reactive with specific members of a fraction of proteins extracted from human sperm heads. An ELISA has been developed in which, by use of a standardized reference serum, the relative values for total IgM and for sperm protein-reactive IgM may be derived for each serum. Those values, determined for 32 adult and 9 neonatal sera, indicate that the sperm protein-reactive IgM antibodies represent a reasonably constant proportion of the total serum IgM titer.