47 research outputs found
Functional Feeding Groups, Species Richness, and Spatial Distributions of Fishes in Rocky and Sandy Beach Habitats of St. John, U.S. Virgin Islands
Objectives were to identify and compare fish species richness, functional feeding group richness and diversity, and delineate distributions of fishes at rocky and sandy beach habitats at St. John, U.S. Virgin Islands. Visual observations using snorkel and mask were made at 3-m intervals seaward from shore during daylight hours. A total of 69 taxa (67 species) representing 33 families of fishes were observed. Total (53) and average fish species richness (32.7) at rocky beach habitats were greater than those (total=43; average=24.3) at sandy beach habitats. Twelve functional feeding groups were identified (diurnal planktivores, excavators/eroders, macroalgae browsers, macrocarnivores, mobile benthic scrapers, general omnivores, strict piscivores, sand invertivores, scrapers, coral/colonial sessile insectivores, territorial algae/detritus, and turf grazers. Total numbers of functional feeding groups (range= 10-12) and species (range= 29-46) per functional feeding groups at distances greater than 1 m from shore at rocky beach habitats were consistently higher than those (functional feeding group range= 8-10; species per functional feeding group = 19-30) at sandy beach habitats. Information on the number and composition of functional feeding groups in rocky and sandy beach habitats from this study can serve as a baseline for future investigations as changes in Caribbean habitats continue to occur
Nest-Building and Spawning Behaviors in Nocomis effusus (Actinopterygii: Cyprindae)
Spawning behavior in Nocomis effusus is described from direct observations and review of videotapes made in Yellow Creek (Cumberland River drainage), Tennessee in 2003. Nest construction (i.e., excavating a concavity, forming a platform, and building a mound), and spawning behavior in N. effusus where a single breeding male excavates a pit and spawns with females on the upstream slope of his nest is like that described for Nocomis asper and Nocomis biguttatus. In digging a spawning pit, a male N. effusus reshapes and reorganizes substrate materials that results in spawning areas on the upstream slope of the nest composed of 6.0 and 11.3 mm size-class pebbles. Aggressive behaviors (in order of increasing aggression) observed between nest-building and intruder male N. effusus were non-contact head displacement, non-contact body displacement, chase, circle swim, and head/body butt. Nest associates (i.e., species that congregate and may spawn in a nest but do not contribute to its construction) observed over nests of N. effusus were Luxilus chrysocephalus and Lythrurus fasciolaris
Effects of Vacuuming Pervious Concrete on Infiltration Rate
The objectives of this research were twofold: test the infiltration rate of pervious concrete before and after vacuum cleaning, and assess infiltration variability over time. Infiltration tests were performed on a 558.2 m2 area of pervious concrete, divided into sixteen 0.35 m2 test areas in a parking area at the Science Museum of Virginia in Richmond, Virginia on five dates from November 4-December 30, 2013. Average infiltration rates (avg.= 22.8 and 36.3 L/m2/min) immediately after vacuuming were lower than those (avg.=30.7 and 41.3 L/m2/min) before vacuuming. We hypothesize that the vacuuming lifted materials towards the surface from deeper crevices of the lower profile of the pervious concrete, which clogged interstices in the upper portion of the pervious concrete, and impeded infiltration. Over time, however, average infiltration rates recovered, increasing significantly from 22.8 -44.1 L/m2/min (93% increase) from November 4 through December 30, 2013 (56 days). Ergo, over time, the infiltration capability of the pervious concrete increased as rains likely washed sediments to lower profiles and allow for increased infiltration rates, consistent with the findings of other studies. Infiltration rates on the leading edge of the pervious concrete area receiving runoff from adjacent impervious asphalt surfaces were significantly lower than those furthest away from the leading edge. In contrast to recommendations specifying that pervious concrete be regularly vacuumed monthly, we propose that annual or semiannual vacuuming of pervious concrete would allow adequate infiltration, and reduce costs significantly for pervious concrete areas located in the mid-Atlantic region
Microstructure of Attachment Mechanisms of Newly Hatched Larvae of Four Cyprinid Species with Comments on Terminology
An adhesive organ is a prominent, protruding mucus secreting gland that is used by newly hatched tadpoles and larvae of some fishes to attach to aquatic vegetation. The objective of this research is to test the hypothesis that newly hatched cyprinid larvae of Hybognathus hankinsoni, Notemigonus crysoleucas, Cyprinus carpio and Gila atraria contain cephalic adhesive organs. Newly hatched larvae of Semotilus atromaculatus, which do not attach to submerged aquatic vegetation, were used as the control. SEM examination of newly hatched larvae indicate there were no adhesive organs on the control species (S. atromaculatus) or test species (H. hankinsoni, N. crysoleucas, C. carpio and G. atraria). Rather, newly hatched larvae of test species contain a localized highly modified epidermis (i.e., primarily on the ventral cephalic and anterioventral yolk sac surfaces of H. hankinsoni, N. crysoleucas, C. carpio, and G. atraria, and sometimes on dorsal cephalic epidermal cells of H. hankinsoni, C. carpio, and G. atraria). This modified epidermis is composed of epidermal cells with unculi-like projections, elevated microridges at peripheries of epidermal cells, and mucus from apical pores of goblet cells that probably are responsible for attachment of test species to substrates. We hypothesize that the unculi-like projections at centers of epidermal cells in newly hatched larval test cyprinids are true unculi. There is a need to define and clarify the meanings of words and phrases (i.e., cement gland, cement gland apparatus, cement gland-like structure, casquette, temporary adhesive glands, adhesive apparatus, adhesive gland, adhesive organ, attachment organ, and glue secretion and adhesion) for structures used by newly hatched larvae to attach to substrates. Definitions should be based on homologies, crucial in phylogenetic reconstructions of species relationships and in identifying developmental homologues of cells, tissues, glands, and organs that have been described as mechanisms for attachment by newly hatched larvae of various species to substrates. We proposed the phrase “attachment mechanism” as a broad definition for the ways in which newly hatched larvae attach and adhere to substrates during early development. This broad definition, however, should be modified to define specific methods of attachment (e.g. attachment mechanism of unculi, elevated epidermal microridges, and mucus) to assist in defining homologies.
Keywords: newly hatched cyprinid larvae, attachment mechanism, SE
Seasonal nearshore distributions of fishes in a piedmont section of the James River, Virginia
The seasonal nearshore distributions of 17 species of fishes were determined in natural and artificially heated areas in a 9.6 km stretch of the Piedmont section of the James River, Virginia from July, 1973 to June, 1974. Analyses of the seasonal distributions were based on abundance and percent frequency of occurrence data. The maximum abundance and percent occurrence of ten of the 17 species of fishes in natural temperature areas occurred in early autumn. Deviations from this pattern included Notropis analostanus, equally abundant throughout the year, and Lepisosteus osseus, Notropis amoenus, Notropis ardens, Notropis rubellus, Catostomus commersoni and Lepomis macrochirus, which were taken most often in periods other than early autumn. In the heated effluent, seven species of fishes attained maximum abundance in late autumn. Exceptions were L. macrochirus, equally abundant throughout the year, and L. osseus, Cyprinus carpio, N. rubellus and Hypentelium nigricans, which were more abundant in the spring. Except for L. macrochirus, all fishes were absent or scarce in the heated effluent when temperatures exceeded 30 C in the summer and early autumn. In the winter abundance values of fishes in the heated effluent were usually comparable to those of ambient temperature locations
Characterization of the Novel Interaction Between Neisseria gonorrhoeae TdfJ and its Human Ligand S100A7
Neisseria gonorrhoeae is an obligate human pathogen that causes the common STI gonorrhea, which presents a growing threat to global health. The WHO estimated 78 million new cases of gonorrhea worldwide in 2017, with estimates of 820,000 new cases in the United States alone according to the CDC. High-frequency phase and antigenic variation inherent in N. gonorrhoeae, coupled with its natural ability to rapidly acquire and stably integrate antimicrobial resistance factors into its genome, have culminated in an infection against which there is no effective vaccine, and for which the list of viable therapeutic options is quickly shrinking. Moreover, no protective immunity against subsequent infections is elicited upon exposure to N. gonorrhoeae, which highlights the need for research of novel antimicrobial and vaccination strategies. Within the human host, N. gonorrhoeae utilizes a unique strategy to overcome host sequestration of essential nutrients – termed nutritional immunity (NI) – such as ions of trace metals. The pathogen produces a family of outer membrane proteins called TonB-dependent transporters (TdTs) capable of binding to host NI factors and stripping them of their nutritional cargo for use by the pathogen. Importantly, these TdTs are very highly conserved and expressed among Neisseria species. TbpA is a well-characterized TdT that allows N. gonorrhoeae to acquire iron from human transferrin, and recent studies from our lab have shown that TdfH is capable of binding to a zinc-sequestering S100 protein called calprotectin and stripping it of its zinc ion. The S100 proteins are EF-hand calcium-binding proteins that naturally play an integral role in Ca2+ homeostasis, but due to their ability to bind transition metals, they have also demonstrated an innate immunity role by participating in nutrient sequestration.
The S100 proteins are expressed in all human cells, and all are capable of binding transition metals including zinc, manganese, and cobalt. Calprotectin, S100A7, and S100A12 have demonstrated an ability to hinder the infection potential of pathogenic E. coli, S. aureus, C. albicans, and various other pathogens via zinc sequestration. Herein, we demonstrate that N. gonorrhoeae is able to overcome this phenomenon and actually utilize these proteins as a zinc source in vitro. Furthermore, we identify S100A7 as the specific ligand for TdfJ, which utilizes this ligand to internalize zinc during infection. S100A7 growth support in vitro is dependent upon a functional TonB, TdfJ, and the cognate ABC transport system ZnuABC, and isogenic mutants incapable of producing znuA or tdfJ recover S100A7 utilization by complementation. Whole-cell binding assays and affinity pulldowns show that S100A7 binds specifically to both gonococcal and recombinant TdfJ, and growth and binding experiments show that these described phenomena are specific to human and not mouse S100A7. Finally, we show that a His-Asn double mutant S100A7 that is incapable of binding zinc cannot be utilized for growth by gonococci. These data illustrate the unique nature of the gonococcus’ ability to co-opt host defense strategies for its own purposes, and further identify the TdTs as promising targets for strategies to combat and prevent gonococcal infection
Historical Relationships of Atlantic Slope River Drainages
An analysis of the historical relationships of 19 river drainages (St. Lawrence to Altamaha) on the Atlantic slope of the Appalachian Mountains was conducted using the shared presence of 124 native species of cyprinid fishes. This analysis resulted in an area cladogram that suggests that the rivers of the southern Atlantic slope were historically connected to the drainage of three southern rivers (Flint, Chattahoochee, and Apalachicola) which drain into the Gulf of Mexico. The mid Atlantic and northern Atlantic slope rivers appear to be historically related in support of earlier hypotheses that the mid Atlantic region provided a refugium for fishes to disperse to the north following the retreat of the glacier and rising sea levels at the end of the Pleistocene. Methods for testing these conclusions are discussed
Variables Associated with Thermal Emittance of Wall Mural Art in Richmond, Virginia
The objectives of this research are to determine the factors associated with the minimum, maximum, and average thermal emittance temperatures of wall murals in Richmond, Virginia, and make recommendations for color and location of wall murals. Data for 17 parameters were collected for 64 art murals in downtown Richmond, VA from 28 June 2018 – 19 July 2018. Date, time, solar exposure duration, solar elevation, latitude, longitude, air temperature (C), lux, color, solar cardinal minutes, cardinal direction, minimum, maximum, and average surface thermal emittance temperatures of mural face were recorded for each mural. We reject the hypothesis that minimum, maximum, and average thermal emittance temperatures of wall murals do not vary significantly with temporal, spatial, physical changes, and solar factors. Maximum, minimum, and average emittance temperatures of wall mural art varied significantly with the number of minutes that solar energy directly illuminating mural art for each cardinal direction, lux, solar elevation, total diurnal exposure, maximum mural color, and percent dark colors on murals. Minimum mural wall art temperatures (30.0-37.0 C) occurred on surfaces facing East, North, Northwest, and Northeast which also had the lowest lux values (8,867-14,231); highest temperatures (44.8-49.9 C) were recorded on walls facing South, Southeast, and West, which had the highest lux values (42,517-46,000). Based on results of this study and those investigating mitigation of the urban heat island effect with building materials and coatings on walls and roofs, we recommend a study that uses a systematic approach to locating wall mural art based on specific colors, paint composition, and wall materials to guide local building authorities owners, and artists to maximize albedo. Additionally, we recommend, where possible, mural art should be painted on vertical surfaces facing North, Northeast, and Northwest where lux values and thermal gain are the lowest of all possible cardinal directions. Such locations could accommodate the use of dark colors without significantly increasing the heat load in urban communities. And finally, where mural art is being considered for building walls facing South, Southeast, Southwest and West, we recommend that artists use a palette of primarily light colors with high reflective properties to maximize albedo, and minimize use of dark colors
Comparison of Larval Myomere Counts Among Species of Nocomis in Virginia (Actinopterygii: Cyprinidae)
Larval myomere counts of Nocomis platyrhynchus were made using a dissecting light microscope equipped with polarizing filters, and then compared to those of the three other species of Nocomis (Nocomis leptocephalus, Nocomis micropogon, and Nocomis raneyi) found in Virginia. Average preanal myomere counts for N. platyrhynchus (26.9) were significantly different from those of the other three species (N. raneyi =28.7; N. micropogon =26.0; and N. leptocephalus =25.9). This is especially important as larvae of N. leptocephalus, the only other species of Nocomis syntopic with N. platyrhynchus in the upper New River drainage, can now be distinguished from those of N. platyrhynchus. Larvae of N. raneyi also can be distinguished from those of other species of Nocomisin Virginia based on preanal myomere counts. However, larvae of N. platyrhynchus and N. raneyi cannot be distinguished from each other based on total myomeres (42.0 versus 41.7). Larvae of N. platyrhynchus can be distinguished from those of three of its nest associates (Lythrurus ardens, Notropis rubellus, and Phoxinus oreas), but not from Campostoma anomalum and Luxilus chrysocephalus using myomere counts