Dennis Kolosov

Dennis Kolosov
California State University, San Marcos | CSUSM · Department of Biological Sciences

PhD in Biology

About

35
Publications
25,323
Reads
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534
Citations
Introduction
I am an enthusiastic early-career researcher (Assistant Professor at California State University San Marcos) studying molecular mechanisms of ion transport in animal epithelia. Models: multiple vertebrate and invertebrate model organisms for the study of epithelial ion transport mechanisms (e.g.,fish gill cell culture and insect Malpighian tubules). Approaches/methodology: bioinformatics, pharmacology, electrophysiology and cell molecular techniques, coupled to functional bioassays.
Additional affiliations
January 2021 - present
California State University, San Marcos
Position
  • Professor (Assistant)
Description
  • Assistant Professor in Animal Physiology - lab research focuses on molecular mechanisms of epithelial ion transport
January 2018 - April 2018
McMaster University
Position
  • Instructor
Description
  • BIO2A03 Integrative Physiology of Animals
September 2017 - present
McMaster University
Position
  • Lecturer
Description
  • BIO3ZZ3 Topics in Physiology
Education
January 2012 - August 2016
York University
Field of study
  • Biology (Animal Physiology)
September 2010 - December 2011
York University
Field of study
  • Animal Physiology
September 2006 - April 2010
York University
Field of study
  • Biology

Publications

Publications (35)
Article
Malpighian tubules (MTs) and the hindgut together constitute the excretory system of insects. Larvae of lepidopterans (butterflies and moths) demonstrate the so-called cryptonephric arrangement, where the distal blind end of each MT is embedded into the rectal complex. The rest of the free tubule is modified into several distinct regions that diffe...
Article
Malpighian tubules (MTs) and hindgut constitute the functional kidney of insects. MTs are outpouches of the gut and in most insects demonstrate proximodistal heterogeneity in function. In most insects, such heterogeneity is confined to ion/fluid secretion in the distal portion and ion/fluid reabsorption in the proximal portion. In contrast, MTs of...
Article
The Malpighian tubules (MTs) and hindgut together act as the functional kidney in insects. MTs of caterpillars are notably complex and consist of several regions that display prominent differences in ion transport. The distal ileac plexus (DIP) is a region of MT that is of particular interest because it switches from ion secretion to ion reabsorpti...
Chapter
Lepidopterans (butterflies and moths) are an ecologically and agriculturally important group of holometabolous insects. Their larvae and adults exhibit trophic partitioning, which is reflected by the various modifications of their digestive and excretory systems. Adults are capable of flight and feed mostly on the nectar of plants, acting as pollin...
Article
The functional kidney in insects consists of the Malpighian tubules and hindgut. Malpighian tubules secrete ions and fluid aiding in hydromineral homeostasis, acid-base balance, and metabolic waste excretion. In many insects, including lepidopterans, the Malpighian tubule epithelium consists of principal cells (PCs) and secondary cells (SCs). The S...
Article
This Review addresses the means by which epithelia change the direction of vectorial ion transport. Recent studies have revealed that insect Malpighian (renal) tubules can switch from secreting to reabsorbing K+. When the gut of larval lepidopterans is empty (during the moult cycle) or when the larvae are reared on K+-deficient diet, the distal ile...
Article
Lamprey are living representatives of the basal vertebrate agnathan lineage. Many lamprey species are anadromous with a complex life cycle that includes metamorphosis from a freshwater (FW) benthic filter-feeding larva into a parasitic juvenile which migrates to seawater (SW) or (in landlocked populations) large bodies of FW. After a juvenile/adult...
Article
The anal papillae of mosquito larvae are osmoregulatory organs in direct contact with the external aquatic environment that actively sequester ions and take up water in dilute freshwater. In the disease vector Aedes aegypti mechanisms of ion, water and ammonia transport have only been partially resolved. Furthermore, A. aegypti larvae are known to...
Article
Full-text available
Significance Beetles are the most diverse animal group on the planet. Their evolutionary success suggests unique physiological adaptations in overcoming water stress, yet the mechanisms underlying this ability are unknown. Here we use molecular genetic, electrophysiology, and behavioral studies to show that a group of brain neurons responds to osmo...
Article
Lepidopterans are among the most widespread and easily recognized insects. Whereas adult lepidopterans are known for their beauty and ecological importance as pollinators and sources of food for other animals, larvae are economically important pests of forests and agricultural crops. In the larval body, rapid growth while feeding on plant-based die...
Article
Transporting epithelia are tissues that specialize in the directional movements of ions and water and are typically either secretory or reabsorptive. Recent work on the Malpighian tubule of larval lepidopterans (caterpillars) demonstrated that the distal ileac plexus segment of this epithelium is capable of rapidly switching between ion secretion a...
Article
The role of lamprey epithelium tight junctions (TJs) in the regulation of salt and water balance is poorly understood. This study reports on claudin (Cldn) TJ protein transcripts of pre-metamorphic larval and post-metamorphic juvenile sea lamprey (Petromyzon marinus) and the transcriptional response of genes encoding Cldns to changed environmental...
Article
Freshwater (FW) fish experience passive paracellular loss of ions into the surrounding environment across water-exposed epithelia such as the gill. The mitigation of paracellular ion loss is thought to be regulated by proteins of the tight junction (TJ) complex and in particular, the large superfamily of claudin (cldn) TJ proteins plays an importan...
Article
A recent study demonstrated that in response to a feeding-induced metabolic acidosis, goldfish Carassius auratus adjust epithelial protein and/or mRNA expression in their kidney tubules for multiple transporters known to be relevant for acid-base regulation. These include Na+/H+-exchanger, V-H+-ATPase, cytoplasmic carbonic anhydrase, HCO3−-transpor...
Article
Full-text available
Springtails (Collembola) are ancient close relatives of the insects. The eversible vesicles are their unique paired transporting organs, which consist of an epithelium located inside a tube-like structure called the collophore on the first abdominal segment. The vesicles can be protruded out of the collophore and several lines of evidence indicate...
Article
Full-text available
Cortisol-induced epithelial tightening of a primary cultured rainbow trout gill epithelium model occurs in association with reduced paracellular permeability and increased abundance of select barrier-forming tight junction (TJ) proteins. Corticosteroid receptor (CR) pharmacological blocker studies have suggested that to produce this tightening effe...
Preprint
Full-text available
Springtails (Collembola) are ancient close relatives of the insects. The eversible vesicles are their unique paired transporting organs, which consist of an epithelium located inside a tube-like structure on the first abdominal segment called the collophore. The vesicles can be protruded out of the collophore and several lines of evidence indicate...
Article
Excretion of metabolic wastes and toxins in insect Malpighian tubules (MTs) is coupled to secretion of ions and fluid. Larval lepidopterans demonstrate a complex and regionalized MT morphology, and recent studies of larvae of the cabbage looper, Trichoplusia ni, have revealed several unusual aspects of ion transport in the MTs. Firstly, cations are...
Article
Full-text available
Insecticide resistance has been reported in many important agricultural pests, and alternative management methods are required. Baculoviruses qualify as an effective, yet environmentally benign, biocontrol agent but their efficacy against generalist herbivores may be influenced by diet. However, few studies have investigated the tritrophic interact...
Article
Excretion in insects is accomplished by the combined actions of the Malpighian tubules (MTs) and hindgut, which together form the functional kidney. MTs of many insect groups consist of principal cells (PC) and secondary cells (SC). In most insect groups SCs are reported to secrete ions from haemolymph into the tubule lumen. Paradoxically, SCs in t...
Article
The molecular physiology of tricellular tight junction (tTJ)-associated proteins; lipolysis-stimulated lipoprotein receptor (lsr, = angulin-1) and an immunoglobulin-like domain-containing receptor (ildr2, ≈ angulin-3), were examined in model trout gill epithelia. Transcripts encoding lsr and ildr2 are broadly expressed in trout organs. A reduction...
Article
This study reports on tight junction-associated MARVEL proteins of larval sea lamprey (Petromyzon marinus) and their potential role in ammocoete osmoregulation. Two Occludin isoforms (designated Ocln and Ocln-a) and a tricellulin (Tric) were identified. Transcripts encoding ocln, ocln-a, and tric were broadly expressed in larval lamprey, with great...
Article
The influence of claudin (Cldn) 8 tight junction (TJ) proteins on cortisol-mediated alterations in gill epithelium permeability were examined using a primary cultured trout gill epithelium model. Genes encoding three Cldn-8 proteins (cldn-8b, -8c and -8d) have been identified in trout and all are expressed in the model gill epithelium. Cortisol tre...
Article
The contribution of Claudin-31 (Cldn-31) to corticosteroid-induced tightening of the trout gill epithelium was examined using a primary cultured model preparation. Cldn-31 is a ∼23 kDa protein that localizes to the periphery of gill epithelial cells and diffusely in select gill cells that are Na⁺-K⁺-ATPase-immunoreactive. Transcriptional knockdown...
Article
This study examined regional distribution and corticosteroid-induced alterations of claudin (cldn) transcript abundance in teleost fish skin. Regional comparison of mRNA encoding 20 Cldns indicated that 12 exhibit differences in abundance along the dorsoventral axis of skin. However, relative abundance of cldns (i.e. most to least abundant) remaine...
Article
Full-text available
This study utilized dietary salt loading and ion-poor water (IPW) exposure of rainbow trout (Oncorhynchus mykiss) to further understand the role of fish gill epithelium tight junction (TJ) physiology in salt and water balance. Gill morphology, biochemistry and molecular physiology were examined, with an emphasis on genes encoding TJ proteins. Fish...
Article
To consider the idea that a dietary botanical supplement could act as an adaptogen in a teleost fish, the effect of a liquorice root derivative (18β-glycyrrhetinic acid, 18βGA) on rainbow trout following an acute ionoregulatory stressor was examined. Freshwater (FW) trout were fed a control or 18βGA supplemented diet (0, 5, or 50 μg 18βGA/g diet) f...
Article
The effect of liquorice root derivatives (LRDs) glycyrrhizic acid (GL) and glycyrrhetinic acid (18βGA) on salt and water balance and endpoints of gill ion transport in a freshwater teleost fish, (rainbow trout, Oncorhynchus mykiss) were examined. Fish were fed diets containing GL or 18βGA (0, 5, 50 or 500μg/g diet) for a two week period. Serum cort...
Article
Full-text available
In vertebrates, tight junction (TJ) proteins play an important role in epithelium formation and development, the maintenance of tissue integrity and regulating TJ permeability. In this study, primary cultured model gill epithelia composed of pavement cells (PVCs) were used to examine TJ protein transcript abundance during the development of epithel...
Article
Full-text available
Teleost fishes are a large and diverse animal group that represent close to 50% of all described vertebrate species. This review consolidates what is known about the claudin (Cldn) family of tight junction (TJ) proteins in teleosts. Cldns are transmembrane proteins of the vertebrate epithelial/endothelial TJ complex that largely determine TJ permea...
Article
Full-text available
The apical-most region of cell-to-cell contact in a vertebrate epithelium is the tight junction (TJ) complex. It is composed of bicellular TJs (bTJs) that bridge two adjacent epithelial cells and tricellular TJs (tTJs) that are points of contact between three adjoining epithelial cells. Tricellulin (TRIC) is a transmembrane TJ protein of vertebrate...
Article
Full-text available
Paracellular permeability characteristics of the fish gill epithelium are broadly accepted to play a key role in piscine salt and water balance. This is typically associated with differences between gill epithelia of teleost fishes residing in seawater versus those in freshwater. In the former, the gill is 'leaky' to facilitate Na(+) secretion and...

Questions

Questions (2)
Question
Hello all,
I have an unusual request. I am starting a lab in California and got my hands on two old (!) but functional qPCR machines - model and make in the title (image attached). However, I do not have a computer to connect them to and by reading through manuals and looking for how these machines used to connect to a computer for data acquisition, it appears that they have to be connected to a Windows XP-based PC, running Opticon software with a National Instruments data acquisition card installed.
Does anyone per chance have one of these computers sitting around - maybe, you used to have the same qPCR machine and it's not gone, but the computer is still available, etc. Or if you have the whole setup - qPCR machine + PC that it connects to. Please contact me if you do - it would be a shame to sell these for parts just because I can't find a computer to connect them to (BioRad doesn't seem to want to support them anymore).
Best regards,
Dennis
Question
I recently started running qPCR on an old Stratagene MX3000P in the common core facility and once in a while it spits out curves like this (see attached image) at me. Anyone encountered this problem before?

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