Ascovirus infectivity and effects of infection on the growth and development of noctuid larvae

The infectivity per os and by inoculation of ascoviruses isolated from Heliothis zea, Spodoptera frugiperda, and Trichopulsia ni and the effects of infection by these viruses on host growth and development were studied in the species from which these viruses were originally isolated, or in the case of the H. zea isolate, in H. virescens. Mortality caused by all three viral isolates averaged less than 15% in third instars fed doses of 10 to 10(5) viral vesicles per larva incorporated into diet, whereas inoculation with as few as 10 viral vesicles consistently yielded mortality rates greater than 90%. In tests where groups of 10 larvae were inoculated sequentially with a minuten pin that had been inserted into the hemocoel of an infected larva and then dried for up to 24 hr, mortality rates were consistently greater than 90%. The latter results suggest that ascoviruses in the field may be vectored by insect parasites. The studies of the effects of infection on larval growth and development demonstrated a marked loss of appetite and a decrease in weight gain within 24-48 hr of infection in all three isolates. Third instars inoculated at a weight of ca. 15 mg gained little weight after infection and had difficulty molting, but survived in an arrested state of development for 2-5 weeks. Controls pupated within 5-7 days after attaining weights, depending on the host species, in the range of 300-500 mg. Arrested development and lack of weight gain appear to be due to decreased feeding, whereas the long survival of infected larvae is likely due to the limited destruction of host tissues.     

Phylogenetic diversification of immunoglobulin genes and the antibody repertoire

Immunoglobulins are encoded by a large multigene system that undergoes somatic rearrangement and additional genetic change during the development of immunoglobulin-producing cells. Inducible antibody and antibody-like responses are found in all vertebrates. However, immunoglobulin possessing disulfide-bonded heavy and light chains and domain-type organization has been described only in representatives of the jawed vertebrates. High degrees of nucleotide and predicted amino acid sequence identity are evident when the segmental elements that constitute the immunoglobulin gene loci in phylogenetically divergent vertebrates are compared. However, the organization of gene loci and the manner in which the independent elements recombine (and diversify) vary markedly among different taxa. One striking pattern of gene organization is the "cluster type" that appears to be restricted to the chondrichthyes (cartilaginous fishes) and limits segmental rearrangement to closely linked elements. This type of gene organization is associated with both heavy- and light-chain gene loci. In some cases, the clusters are "joined" or "partially joined" in the germ line, in effect predetermining or partially predetermining, respectively, the encoded specificities (the assumption being that these are expressed) of the individual loci. By relating the sequences of transcribed gene products to their respective germ-line genes, it is evident that, in some cases, joined-type genes are expressed. This raises a question about the existence and/or nature of allelic exclusion in these species. The extensive variation in gene organization found throughout the vertebrate species may relate directly to the role of intersegmental (V<==>D<==>J) distances in the commitment of the individual antibody-producing cell to a particular genetic specificity. Thus, the evolution of this locus, perhaps more so than that of others, may reflect the interrelationships between genetic organization and function.      

Optimal local propensities for model proteins

Lattice models of proteins were used to examine the role of local propensities in stabilizing the native state of a protein, using techniques drawn from spin-glass theory to characterize the free-energy landscapes. In the strong evolutionary limit, optimal conditions for folding are achieved when the contributions from local interactions to the stability of the native state is small. Further increasing the local interactions rapidly decreases the foldability. © 1995 Wiley-Liss, Inc.     

Immunohistochemical distribution of MAM-3 and MAM-6 antigens in developing salivary glands of the human fetus

Summary The immunohistochemical expression of MAM-3 and MAM-6 antigens was studied in developing human fetal salivary gland removed at autopsy of 22 normal fetuses of varying maturity (10–40 weeks of gestation). The onset of functional maturation in the fetal gland was seen at 21 weeks of gestational maturity. The acini and ducts then underwent distinct alterations in antigen expression with growth and maturation until the late developmental stage (33–40 weeks of gestation) when they resemble the adult salivary gland. The role of maturing duct cells in histogenesis of salivary gland tumours is discussed.     

Prevalence of Hepatitis δ (Delta) Virus Infection A Seroepidemiologic Study

In assessing the prevalence of hepatitis δ (delta) virus (HDV) infection in 358 patients with acute hepatitis B seen in Los Angeles between 1983 and 1985 and in 196 patients with chronic hepatitis B followed between 1980 and 1985, we found that 23% of patients with chronic and 5% of patients with acute hepatitis B were infected with HDV. Among patients with chronic hepatitis B, the prevalence of HDV infection was 73% in intravenous drug users and 14% in homosexual men. Acute coinfection with the hepatitis B virus was also more frequent in drug users (8%) than in other groups. δ-Hepatitis is a common infection in hepatitis B virus carriers in Los Angeles, particularly in drug addicts, but also in homosexual men who do not abuse drugs intravenously.     

Green synthesis of ZnO nanoparticles for antimicrobial and vegetative growth applications: A novel approach for advancing efficient high quality health care to human wellbeing

The present work aims to synthesize zinc oxide (ZnO) nanoparticles via green approaches using leaf extract of Parthenium hysterophorus. UV–vis and FT-IR tests confirmed the existence of biomolecules, active materials, and metal oxides. The X-ray diffraction structural study exposes the ZnO nanoparticles formation with hexagonal phase structures. SEM and TEM analysis reveal surface morphologies of ZnO nanoparticles and most of them are spherical with a size range of 10 nm. ZnO nanoparticles were revealed strong antimicrobial activity against both bacterial and fungal strains. The germination of seeds and vegetative growth of Sesamum indicum has been greatly improved.