Tillering Response of \u27Monon\u27 And \u27Newton\u27 Winter Wheats Infested With Biotype L Hessian Fly (Diptera: Cecidomyiidae) Larvae

Two wheat, Triticum aestivum, cultivars that differed in their ability to tiller were infested by ovipositing Hessian flies, Mayetiola destructor, under similar controlled conditions. Since a larva typically stunts and kills the stem where it feeds and develops, tiller development of fly infested-wheat seedlings is an important plant trait relative to grain yield. \u27Monon\u27 tillered more than \u27Newton at the 0 infestation level (control). \u27Monon\u27 had about the same number of tillers at 0, 1, 2, and 3 puparia (indicative of the number of feeding larvae) per plant; and \u27Newton\u27 had fewer tillers at 0 than 1, 2, or 3 puparia per stem. However, tillering of both cultivars was less at 4 or more puparia per stem, perhaps due to the depletion of plant nutrients. In general, for both cultivars there was a decrease in leaf length, number and wet weight as the number of puparia increased per tiller

Electroantennogram Responses of the Armyworm (Lepidoptera: Noctuidae) and Cereal Leaf Beetle (Coleoptera: Chrysomelidae) to Volatile Chemicals of Seedling Oats

Armyworm, Pseudaletia unipuncta, eIectroantennogram (EAG) responses to 10 volatile chemicals of seedling oats and three of injured green plants were significantly different from each other while cereal leaf beetle, Oulema melallopus, EAG responses were not significantly different. The EAG responses of both species did not vary significantly with respect to sex, age, or between the antennae of the same specimen. (E)-2-hexenol, a compound extracted from injured green plants, yielded the highest peak response for the armyworm while more cereal leaf beetle antennae responded to this chemical than any other chemical. Armyworm antennallife averaged 38 + 20 min while those of the cereal leaf beetle averaged 6 + 14 min

Storage and Behavior of Plant and Diet-Fed Adult Cereal Leaf Beetle, Oulema Melanopus (Coleoptera: Chrysomelidae)

The univoltine life cycle of the cereal leaf beetle Oulema melanopus (L.) in Michigan (Castro et al. 1965) is similar to that reported by Venturi (1942) in Europe. Adults emerge from pupal cells in the soil in mid-June to early July, feed voraciously for about three weeks, and enter aestivation sites. For the remainder of the summer and early autumn only a few adults can be found feeding on late-maturing native grasses. The beetles overwinter and usually emerge in late March to early April and resume feeding. Mating and oviposition occur, and larval development is usually completed by late June in southern Michigan. Techniques for rearing the cereal leaf beetle on greenhouse-grown small grain seedlings have been developed by Connin, et al. (1968). Maintaining these cultures requires collecting field adults, growing host material, and handling the cultures to insure that all stages will be available for study. In Michigan during July adults can be collected more economically and in greater numbers in the field than by rearing in the laboratory. A summary of collection techniques, laboratory feeding and storage conditions for large numbers of field-collected cereal leaf beetles is presented in this paper. In addition, the mortality during storage of newly emerged field collected beetles fed either barley seedlings or an artificial diet is compared

Storage and Behavior of Plant and Diet-Fed Adult Cereal Leaf Beetle, Oulema Melanopus (Coleoptera: Chrysomelidae)

The univoltine life cycle of the cereal leaf beetle Oulema melanopus (L.) in Michigan (Castro et al. 1965) is similar to that reported by Venturi (1942) in Europe. Adults emerge from pupal cells in the soil in mid-June to early July, feed voraciously for about three weeks, and enter aestivation sites. For the remainder of the summer and early autumn only a few adults can be found feeding on late-maturing native grasses. The beetles overwinter and usually emerge in late March to early April and resume feeding. Mating and oviposition occur, and larval development is usually completed by late June in southern Michigan. Techniques for rearing the cereal leaf beetle on greenhouse-grown small grain seedlings have been developed by Connin, et al. (1968). Maintaining these cultures requires collecting field adults, growing host material, and handling the cultures to insure that all stages will be available for study. In Michigan during July adults can be collected more economically and in greater numbers in the field than by rearing in the laboratory. A summary of collection techniques, laboratory feeding and storage conditions for large numbers of field-collected cereal leaf beetles is presented in this paper. In addition, the mortality during storage of newly emerged field collected beetles fed either barley seedlings or an artificial diet is compared

V3 Loop Truncations in HIV-1 Envelope Impart Resistance to Coreceptor Inhibitors and Enhanced Sensitivity to Neutralizing Antibodies

The V1/V2 region and the V3 loop of the human immunodeficiency virus type I (HIV-1) envelope (Env) protein are targets for neutralizing antibodies and also play an important functional role, with the V3 loop largely determining whether a virus uses CCR5 (R5), CXCR4 (X4), or either coreceptor (R5X4) to infect cells. While the sequence of V3 is variable, its length is highly conserved. Structural studies indicate that V3 length may be important for interactions with the extracellular loops of the coreceptor. Consistent with this view, genetic truncation of the V3 loop is typically associated with loss of Env function. We removed approximately one-half of the V3 loop from three different HIV-1 strains, and found that only the Env protein from the R5X4 strain R3A retained some fusion activity. Loss of V1/V2 (ΔV1/V2) was well tolerated by this virus. Passaging of virus with the truncated V3 loop resulted in the derivation of a virus strain that replicated with wild-type kinetics. This virus, termed TA1, retained the V3 loop truncation and acquired several adaptive changes in gp120 and gp41. TA1 could use CCR5 but not CXCR4 to infect cells, and was extremely sensitive to neutralization by HIV-1 positive human sera, and by antibodies to the CD4 binding site and to CD4-induced epitopes in the bridging sheet region of gp120. In addition, TA1 was completely resistant to CCR5 inhibitors, and was more dependent upon the N-terminal domain of CCR5, a region of the receptor that is thought to contact the bridging sheet of gp120 and the base of the V3 loop, and whose conformation may not be greatly affected by CCR5 inhibitors. These studies suggest that the V3 loop protects HIV from neutralization by antibodies prevalent in infected humans, that CCR5 inhibitors likely act by disrupting interactions between the V3 loop and the coreceptor, and that altered use of CCR5 by HIV-1 associated with increased sensitivity to changes in the N-terminal domain can be linked to high levels of resistance to these antiviral compounds

A cellular trafficking signal in the SIV envelope protein cytoplasmic domain is strongly selected for in pathogenic infection

The HIV/SIV envelope glycoprotein (Env) cytoplasmic domain contains a highly conserved Tyr-based trafficking signal that mediates both clathrin-dependent endocytosis and polarized sorting. Despite extensive analysis, the role of these functions in viral infection and pathogenesis is unclear. An SIV molecular clone (SIVmac239) in which this signal is inactivated by deletion of Gly-720 and Tyr-721 (SIVmac239ΔGY), replicates acutely to high levels in pigtail macaques (PTM) but is rapidly controlled. However, we previously reported that rhesus macaques and PTM can progress to AIDS following SIVmac239ΔGY infection in association with novel amino acid changes in the Env cytoplasmic domain. These included an R722G flanking the ΔGY deletion and a nine nucleotide deletion encoding amino acids 734–736 (ΔQTH) that overlaps the rev and tat open reading frames. We show that molecular clones containing these mutations reconstitute signals for both endocytosis and polarized sorting. In one PTM, a novel genotype was selected that generated a new signal for polarized sorting but not endocytosis. This genotype, together with the ΔGY mutation, was conserved in association with high viral loads for several months when introduced into naïve PTMs. For the first time, our findings reveal strong selection pressure for Env endocytosis and particularly for polarized sorting during pathogenic SIV infection in vivo

Engineering HIV-Resistant Human CD4+ T Cells with CXCR4-Specific Zinc-Finger Nucleases

HIV-1 entry requires the cell surface expression of CD4 and either the CCR5 or CXCR4 coreceptors on host cells. Individuals homozygous for the ccr5Δ32 polymorphism do not express CCR5 and are protected from infection by CCR5-tropic (R5) virus strains. As an approach to inactivating CCR5, we introduced CCR5-specific zinc-finger nucleases into human CD4+ T cells prior to adoptive transfer, but the need to protect cells from virus strains that use CXCR4 (X4) in place of or in addition to CCR5 (R5X4) remains. Here we describe engineering a pair of zinc finger nucleases that, when introduced into human T cells, efficiently disrupt cxcr4 by cleavage and error-prone non-homologous DNA end-joining. The resulting cells proliferated normally and were resistant to infection by X4-tropic HIV-1 strains. CXCR4 could also be inactivated in ccr5Δ32 CD4+ T cells, and we show that such cells were resistant to all strains of HIV-1 tested. Loss of CXCR4 also provided protection from X4 HIV-1 in a humanized mouse model, though this protection was lost over time due to the emergence of R5-tropic viral mutants. These data suggest that CXCR4-specific ZFNs may prove useful in establishing resistance to CXCR4-tropic HIV for autologous transplant in HIV-infected individuals

Structural Repertoire of HIV-1-Neutralizing Antibodies Targeting the CD4 Supersite in 14 Donors

The site on the HIV-1 gp120 glycoprotein that binds the CD4 receptor is recognized by broadly reactive antibodies, several of which neutralize over 90% of HIV-1 strains. To understand how antibodies achieve such neutralization, we isolated CD4-binding-site (CD4bs) antibodies and analyzed 16 co-crystal structures –8 determined here– of CD4bs antibodies from 14 donors. The 16 antibodies segregated by recognition mode and developmental ontogeny into two types: CDR H3-dominated and VH-gene-restricted. Both could achieve greater than 80% neutralization breadth, and both could develop in the same donor. Although paratope chemistries differed, all 16 gp120-CD4bs antibody complexes showed geometric similarity, with antibody-neutralization breadth correlating with antibody-angle of approach relative to the most effective antibody of each type. The repertoire for effective recognition of the CD4 supersite thus comprises antibodies with distinct paratopes arrayed about two optimal geometric orientations, one achieved by CDR H3 ontogenies and the other achieved by VH-gene-restricted ontogenies