New mite invasions in citrus in the early years of the 21st century

Several mite species commonly attack cultivated citrus around the world. Up to 104 phytophagous species have been reported causing damage to leaves, buds and fruits, but only a dozen can be considered major pests requiring control measures. In recent years, several species have expanded their geographical range primarily due to the great increase in trade and travel worldwide, representing a threat to agriculture in many countries. Three spider mite species (Acari: Tetranychidae) have recently invaded the citrus-growing areas in the Mediterranean region and Latin America. The Oriental red mite, Eutetranychus orientalis (Klein), presumably from the Near East, was detected in southern Spain in 2001. The Texas citrus mite, Eutetranychus banksi (McGregor), is widely distributed in North, Central and South America. It was first reported in Europe in 1999 on citrus in Portugal; afterwards the mite invaded the citrus orchards in southern Spain. In Latin America, the Hindustan citrus mite, Schizotetranychus hindustanicus (Hirst), previously known only from citrus and other host plants in India, was reported causing significant damage to citrus leaves and fruits in Zulia, northwest Venezuela, in the late 1990s. Later, this mite species spread to the southeast being detected on lemon trees in the state of Roraima in northern Brazil in 2008. Whereas damage levels, population dynamics and control measures are relatively well know in the case of Oriental red mite and Texas citrus mite, our knowledge of S. hindustanicus is noticeably scant. In the present paper, information on pest status, seasonal trends and natural enemies in invaded areas is provided for these species, together with morphological data useful for identification. Because invasive species may evolve during the invasion process, comparison of behavior, damage and management options between native and invaded areas for these species will be useful for understanding the invader’s success and their ability to colonize new regions.     

Equine Infectious Anemia Virus Gag Polyprotein Late Domain Specifically Recruits Cellular AP-2 Adapter Protein Complexes during Virion Assembly

We have identified an interaction between the equine infectious anemia virus (EIAV) late assembly domain and the cellular AP-2 clathrin-associated adapter protein complex. A YXXL motif within the EIAV Gag late assembly domain was previously characterized as a sequence critical for release of assembling virions. We now show that this YXXL sequence interacts in vitro with the AP-50 subunit of the AP-2 complex, while the functionally interchangeable late assembly domains carried by the Rous sarcoma virus p2b protein and human immunodeficiency virus type 1 p6 protein, which utilize PPPY and PTAPP L domains, respectively, do not bind AP-50 in vitro. In addition, EIAV late domain mutants containing mutations that have previously been shown to abrogate budding also exhibit marked decreases in AP-50 binding efficiencies. A role for AP-2 complex in viral assembly is supported by immunofluorescence analysis of EIAV-infected equine dermal cells demonstrating specific colocalization of the α adaptin subunit of AP-2 with the EIAV p9 protein at sites of virus budding on the plasma membrane. These data provide strong evidence that EIAV utilizes the cellular AP-2 complex to accomplish virion assembly and release.     

Computer-Assisted Image Analysis of Plant Growth, Thigmomorphogenesis, and Gravitropism

A nonintrusive auxonometric system, based on the DARWIN image processor (Telewski et al. 1983 Plant Physiol 72: 177-181), is described and demonstrated in the analysis of gravitropism and thigmomorphogenesis in corn seedlings (Zea mays). Using this system, growth and bending of regularly shaped plants or organs can be quickly and accurately measured without, in any way, interfering with the plant. Furthermore, the growth and bending curves are automatically plotted. Thigmomorphogenesis in the aerial part of corn seedlings involves growth promotion at a low force load and growth retardation at higher force loads. The time courses of the two kinds of response are somewhat different, with retardation occurring immeditely after mechanical perturbation and growth promotion taking somewhat longer to begin. Gravitropic experiments show that when dark-grown corn seedlings are placed on their side in the light, the resulting curvature is due to two consecutive morphological mechanisms. In the first instance, lasting for about 15 minutes, the elongation of the bottom edge of the plant accelerates, while the elongation of the top edge remains constant. After that, for the next 1.75 hours, the elongation of the top edge decelerates and stops while that of the bottom edge remains constant at the increased rate for most of the period. The measurements taken from both experiments at relatively high resolution (0.08-0.1 millimeter) show that the growth curves are not smooth but show many small irregularities which may or may not involve micronutations.     

Visualization and interpretation of birth defects data using linked micromap plots

BACKGROUND: Many states have implemented birth defects surveillance systems to monitor and disseminate information regarding birth defects. However, many of these states rely on tabular methods to disseminate statistical birth defects summaries. An innovative presentation technique for birth defect data that portrays the information in a joint geographical and statistical context is the linked micromap (LM) plot. METHODS: LM plots were generated for oral cleft data at two geographical resolutions—USA states and counties of Utah. The LM plots also included demographic and behavioral risk data. RESULTS: A LM plot for the USA reveals spatial patterns indicating higher oral cleft occurrence in the southwest and the midwest and lower occurrence in the east. The LM plot also indicates relationships between oral cleft occurrence and maternal smoking rates and the proportion of American Indians and Alaskan Natives. In particular, the five states with the highest oral cleft occurrence had a higher proportion of American Indians and Alaskan Natives. Among the 15 states with the highest oral cleft occurrence, nine had a smoking rate of 16% or higher while among the 15 states with the lowest oral cleft occurrence only one state had a smoking rate greater than 16%. The LM plot for the state of Utah shows no clear geographic pattern, due perhaps to a relatively small number of cases in a limited geographic area. CONCLUSIONS: LM plots are effective in representing complex and large volume birth defects data. Integration to birth defects surveillance systems will improve both presentation and interpretation. Birth Defects Research (Part A), 2008. © 2007 Wiley‐Liss, Inc.     

Neuroactive diol and acyloin metabolites from cone snail-associated bacteria

The bacterium Gordonia sp. 647 W.R.1a.05 was cultivated from the venom duct of the cone snail, Conus circumcisus. The Gordonia sp. organic extract modulated the action potential of mouse dorsal root ganglion neurons. Assay-guided fractionation led to the identification of the new compound circumcin A (1) and 11 known analogs (2–12). Two of these compounds, kurasoin B (7) and soraphinol A (8), were active in a human norepinephrine transporter assay with K_i values of 2575 and 867 nM, respectively. No neuroactivity had previously been reported for compounds in this structural class. Gordonia species have been reproducibly isolated from four different cone snail species, indicating a consistent association between these organisms.     

Expression and characterization of the C345C/NTR domains of complement components C3 and C5

Complement components C3, C4, and C5 are members of the thioester-containing alpha-macroglobulin protein superfamily. Within this superfamily, a unique feature of the complement proteins is a 150-residue-long C-terminal extension of their alpha-subunits that harbors three internal disulfide bonds. Previous reports have suggested that this is an independent structural module, homologous to modules found in other proteins, including netrins and tissue inhibitors of metalloproteinases. Because of its distribution, this putative module has been named both C345C and NTR. To assess the structures of these segments of the complement proteins, their relationships with other domains, and activities as independent structures, we expressed C345C from C3 and C5 in a bacterial strain that permits cytoplasmic disulfide bond formation. Affinity purification directly from cell lysates yielded recombinant C3- and C5-C345C with properties consistent with multiple intramolecular disulfide bonds and high beta-sheet contents. rC5-, but not rC3-C345C inhibited complement hemolytic activity, and surface plasmon resonance studies revealed that rC5-C345C binds to complement components C6 and C7 with dissociation constants of 10 and 3 nM, respectively. Our results provide strong evidence that this binding corresponds to the previously described reversible binding of C5 to C6 and C7, and taken together with earlier work, indicate that the C5-C345C module interacts directly with the factor I modules in C6 and C7. The high binding affinities suggest that complexes composed of C5 bound to C6 or C7 exist in plasma before activation and may facilitate assembly of the complement membrane attack complex.     

Effects of season and social interaction on fecal testosterone metabolites in wild male giant pandas: implications for energetics and mating strategies

In the first-ever study of reproductive endocrinology in wild male giant pandas (Ailuropoda melanoleuca), we provide new insights into the reproductive ecology of the species. We tracked and observed pandas in Foping Nature Reserve of the Qinling Mountains for 3 years, collecting fecal samples for testosterone metabolite analysis and data on reproductive activity. Males encountered multiple potential mates and competed for reproductive access to females. Male testosterone metabolites increased in February, peaked in March and April, and fell back to baseline after the mating season. However, males did not maintain a high testosterone level throughout the mating season. Male testosterone instead peaked during encounters with potential mates and declined between encounters. These results indicate that testicular activity is typically dormant until mobilized by interactions with females and potentially by interactions with male competitors. This suggests that male pandas may be energetically constrained, elevating testosterone levels only when necessary to meet the demands of intrasexual competition and courtship and fertilization of females. Maintaining a high testosterone level is metabolically expensive and male pandas enter the mating season during a period of low food availability. If this hypothesis is correct, male panda body condition may be an important determinant of reproductive outcome, and anthropogenic activities that diminish foraging resources may have significant impacts on the mating ecology of the species, affecting its conservation.     

Molecular and kinetic alterations of muscle AMP deaminase during chronic creatine depletion

We examined apossible mechanism to account for the maintenance of peak AMPdeamination rate in fast-twitch muscle of rats fed the creatine analog-guanidinopropionic acid (-GPA), in spite of reduced abundance ofthe enzyme AMP deaminase (AMPD). AMPD enzymatic capacity (determined atsaturating AMP concentration) and AMPD protein abundance (Western blot)were coordinately reduced ~80% in fast-twitch white gastrocnemiusmuscle by -GPA feeding over 7 wk. Kinetic analysis of AMPD in thesoluble cell fraction demonstrated a single Michaelis-Menten constant(K_m; ~1.5 mM) in control muscle extracts. An additional high-affinityK_m (~0.03 mM)was revealed at low AMP concentrations in extracts of -GPA-treated muscle. The kinetic alteration in AMPD reflects increased molecular activity at low AMP concentrations; this could account for high ratesof deamination in -GPA-treated muscle in situ, despite the loss ofAMPD enzyme protein. The elimination of this kinetic effect bytreatment of -GPA-treated muscle extracts with acid phosphatase invitro suggests that phosphorylation is involved in the kinetic controlof skeletal muscle AMPD in vivo.

     

Global dysfunction of CD4 T-lymphocyte cytokine expression in simian-human immunodeficiency virus/SIV-infected monkeys is prevented by vaccination

Human immunodeficiency virus type 1 infection results in a dysfunction of CD4(+) T lymphocytes. The intracellular events contributing to that CD4(+) T-lymphocyte dysfunction remain incompletely elucidated, and it is unclear whether aspects of that dysfunction can be prevented. The present studies were pursued in a rhesus monkey model of AIDS to explore these issues. Loss of the capacity of peripheral blood CD4(+) T lymphocytes to express cytokines was first detected in simian immunodeficiency virus-infected monkeys during the peak of viral replication during primary infection and persisted thereafter. Moreover, infected monkeys with progressive disease had peripheral blood CD4(+) T lymphocytes that expressed significantly less cytokine than infected monkeys that had undetectable viral loads and intact CD4(+) T-lymphocyte counts. Importantly, CD4(+) T lymphocytes from vaccinated monkeys that effectively controlled the replication of a highly pathogenic immunodeficiency virus isolate following a challenge had a preserved functional capacity. These observations suggest that an intact cytokine expression capacity of CD4(+) T lymphocytes is associated with stable clinical status and that effective vaccines can mitigate against CD4(+) T-lymphocyte dysfunction following an AIDS virus infection.