Nanomechanical force measurements of gliadin protein interactions

The strength and nature of interactions between monomeric gliadin proteins involving alpha-alpha, omega-omega, and alpha-omega interactions in 0.01M acetic acid, and the effect of urea has been investigated. It was shown by means of nanomechanical force measurements that the stretching events in the separation curve after adhesive phenomena originated from proteins. These stretching events displayed different responses of the alpha- and omega-gliadins to urea. While 2M urea caused the more globular alpha-gliadins to unfold, the beta-turn-rich omega-gliadins remained fairly stable even in 8M urea. This suggests different roles for gliadins in the formation of dough; while the omega-gliadins are still in a compact structure being responsible for the viscous flow, the alpha-gliadins have already started to participate in forming the network in dough.

The effects of spinosad to beneficial insects and mites and its use in IPM

The effects of spinosad to beneficial and non-target arthropods has been extensively researched. Data have been generated under laboratory, semi-field and field conditions on a wide range of predatory and parasitic taxa in a variety of geographical regions and crop types. Such a large body of data cannot be summarized in detail in a single publication; however, general patterns of effects exist in the data. The aim of this paper is to demonstrate the range of effects of spinosad to beneficial predatory and parasitic arthropods. This is done by presenting in detail selected laboratory, semi-field and field test with beneficial arthropods. Following that an analysis of a database of effects is conducted using records taken from Dow AgroSciences and independent reports. Using these illustrations the profile of effects on a range of predatory and parasitic arthropods are clearly defined. Research has demonstrated that when used according to good agricultural or horticultural practice spinosad is of low risk to predatory mites and beneficial insect populations. Toxicity has been reported to certain parasitic hymenoptera but due to the very short persistence of the product any effects are short lived and followed by rapid recovery. This makes the product an ideal tool in vegetable, pome and pear crops where it can be used to control, thrips caterpillar pests and Psylla. Overall, spinosad preserves natural populations of predatory mites and beneficial insects which make it an ideal choice in IPM programmes.

Results from two years of field studies to determine Mancozeb based spray programmes with minimal impact on predatory mites in European vine cultivation

Mancozeb is a dithiocarbamate fungicide with contact activity against a wide range of economically important fungal diseases. Its multi-site mode of action means that to date there have been no recorded incidences of resistance developing despite many years of use on high risk diseases. One such disease, Grape downy mildew (Plasmopara viticola) has developed resistance to a wide range of important oomycete specific fungicides following their introduction onto the market. The role of Mancozeb either as a mixing or alternation partner in helping to manage these resistance situations remains critically important. Historical use patterns for mancozeb in tree and vine crops involved many applications of product at high use rates. Although this gave excellent disease control, a negative impact on predatory mites was often reported by researchers. This has lead to the development of mancozeb spray programmes in vines and other crops with a much reduced impact on predatory mites. A range of field studies was conducted over two years in France, Germany, Italy, Portugal and Spain where 2, 3 or 4 applications of mancozeb containing products were made per season at different spray timings. In this paper findings from field studies over two years in five different vine growing regions in Europe indicated that two to four applications of mancozeb at 1.6 kg a.i./ha as part of a spray programme caused minimal impact on naturally occurring populations of predatory mites which in turn was compatible with Integrated Pest Management programmes and the conservation of predatory mites.

Field studies to determine the effects of spinosad on the predatory bugs Anthocoris nemoralis and A. nemorum

The predatory bugs Anthocoris nemoralis and A. nemorum are important predators of the pear psylla (Psylla pyri) in pear orchards. To effectively control psylla infestations the use of insecticide treatments are often necessary so it is desirable to adopt products and use patterns which protect or conserve natural predator populations. Spinosad (the active ingredient in TRACER* insecticide) is highly active on psylla when applied up to two times after flowering. To investigate the effects of spinosad on A. nemoralis and A. nemorum a series of field trials were conducted between 1998 and 2005 in pear. Findings from these trials showed that spinosad applied at the psylla rate may cause minor short term effects on A. nemoralis and A. nemorum specifically to very young (or recently hatched) nymphs. However, due to the rapid photodegradation of spinosad recovery of predatory bug populations follows a few days after final application. The occasional depressive effect due to spinosad applications was considered to be due mainly to the removal of the pear psylla prey as spinosad has excellent efficacy on this pest. Findings from the trials demonstrated that predatory bug populations recover rapidly within a few days after the second application in order to control any new pear psylla attack. Therefore, spinosad can be considered as a valuable new tool for controlling pear psylla populations in pear orchards and to be compatible with augmented biological control by the predatory bug population.

Imaging of human metaphase chromosomes by atomic force microscopy in liquid

Human metaphase chromosomes were observed using an intermittent contact mode of atomic force microscopy (AFM) in a phosphate-buffered saline solution to clarify their conformation close to that in the physiological state. In the AFM images in liquid, symmetric alternating ridges and grooves were evident on their surface of the paired sister chromatids. The number of the ridges and grooves were rather specific to the type of the chromosome. The structural changes of chromosomes caused by trypsin treatment were also directly observable using AFM in liquid. These results suggest that the intermittent contact mode AFM is useful not only for analyzing the structure of chromosomes in a liquid condition but also for studying the effect of chemical treatments on chromosomes in relation to their structural changes.

Field studies to determine mancozeb based spray programmes with minimal impact on predatory mites in European vine cultivation

Mancozeb is an ethylene bisdithiocarbamate (EBDC) fungicide with contact activity against a wide range of economically important fungal diseases. Its multi-site mode of action means that to date there have been no recorded incidences of resistance developing despite many years of use on high risk diseases. One such disease, Grape downy mildew (Plasmopara viticola) has developed resistance to a number of important oomycete specific fungicides following their introduction onto the market. The role of Mancozeb either as a mixing or alternation partner in helping to manage these resistance situations remains critically important. Historical use patterns for mancozeb in tree and vine crops involved many applications of product at high use rates. Although this gave excellent disease control, a negative impact on predatory mites has been reported by researchers. This has lead to the development of mancozeb spray programmes in vines and other crops with a much reduced impact on predatory mites. A range of field studies was conducted in France, Germany, Italy, Portugal and Spain where either 2 or 4 applications of mancozeb containing products were made per season at different spray timings. These trials covered the representative range of uses, agronomic practices, mite species and geographical locations in Europe. In this paper findings from ten field studies in five different vine growing regions in Europe indicated that two to four applications of mancozeb at 1.6 kg a.i./ha as part of a spray programme caused minimal impact on naturally occurring populations of predatory mites which in turn was compatible with Integrated Pest Management programmes and the conservation of predatory mites.

The effects of spinosad, a naturally derived insect control agent, to the honeybee (Apis melifera)

Spinosad is a novel insect control agent derived by fermentation of the Actinomycete bacterium, Saccharopolyspora spinosa. Spinosad controls many caterpillar pests in vines, pome fruit and vegetables (including tomatoes and peppers), thrips in tomatoes, peppers and ornamental cultivation and dipterous leafminers in vegetables and ornamentals. Application rates vary between 25 to 100 g of active substance per hectare (g as/ha) and 4.8 to 36 g of active substance per hectolitre (g as/hL) depending on the crop and target pest. It is important that plant protection products are authorized for use only in ways that do not pose an unacceptable risk of harm to honeybees. For this purpose testing was performed to enable the safety of spinosad to be evaluated. The effects of spinosad to honeybees have been extensively researched. Testing has been performed under a variety of conditions in a range of countries globally. Studies to determine the acute toxicity of spinosad under laboratory conditions were conducted to generate LD50 or LC50 values for oral and contact routes of administration. These demonstrated that spinosad was highly toxic to worker honeybees under worst case laboratory conditions and that the oral route of exposure provided the greater risk. Residue tests conducted under laboratory, semi-field and field conditions on worker honeybees foraging on treated foliage indicated that dry product residues were harmless. Therefore the effects seen in the laboratory acute toxicity tests did not translate to a more realistic exposure scenario indicating that safe use patterns for the product can be developed. Semi-field cage studies have also demonstrated that spinosad was safe to bees when applied to flowering crops during periods of bee activity. The majority of studies conducted have indicated that spinosad does not adversely affect honeybee behaviour, brood or queen. It can be concluded that spinosad when used according to the approved product label recommendations, would be safe to foraging worker bees, queen and brood. Additional levels of safety could be achieved by avoiding situations where bees would forage primarily on aphid honey dew.

Evidence for negative cross resistance to insecticides in field collected Spodoptera littoralis (Boisd.) from Lebanon in laboratory bioassays

A sample of Spodoptera littoralis pupae were field collected from in Lebanon in November 1999. Approximately 50 healthy pupae were used to initiate a laboratory colony (stain code LEB). As a benchmark for sensitivity to insecticides the susceptible laboratory strain (LET) was used for comparison. The LET stain has been held in laboratory culture for over 10 years and originated from Israel. Three test chemicals were investigated; Spinosad (Tracer, 480 g/L SC), chlorpyrifos (Dursban 480 g/L EC) and cypermethrin (Ambush C 100 g/L EC) representing a range of different modes of actions. To estimate the sensitivity of the LEB strain relative to the LET stain laboratory bioassays, conducted on second instar larvae exposed treated tomato leaves for two days. The method used was based on IRAC (Insecticide Resistance Action Committee) insecticide susceptibly test number 7. Larvae from the LEB strain were tested in both the F1 and F2 laboratory generations. LC50 values were calculated using a Log-Probit model allowing the susceptibly of each strain to each test item to be compared. The LEB (field) strain were approximately twice as sensitive to spinosad compared with the LET (laboratory) strain. The LEB strain was 6-10 times less sensitive to chlorpyrifos which was within the range expected. However the LEB stain was 250-360 times less sensitive to cypermethrin compared with the LET strain, indicating a high level of resistance to pyrethroids in the field population. This kind of relationship gave a strong indication for negative cross resistance between spinosad and cypermethrin. It was concluded that spinosad had potential as a resistance management tool due to its novel mode of action and negative cross resistance with pyrethroids.

Knowledge and management of disabling conditions in South Asian histories: implications for leprosy futures

Elimination of leprosy as a public health problem appears feasible in South Asia in the present decade through multi-drug therapy, but management of disability in cured leprosy patients will continue through the 21st century, probably with some ongoing stigma. This paper provides new perspectives on leprosy-related disabilities by reviewing the historical careers of four disabling conditions sharing some features with leprosy: lathyrism, iodine deficiency disorders (IDD), cataract and poliomyelitis. All are targeted for eradication or serious reduction using affordable surgery or preventive measures, yet they have proved unexpectedly resilient. Technical solutions alone bring only partial success. There is a need also for community-based delivery methods, individual and family self-help, and some redeployment of professional expertise.

Effect of resistance training on women's strength/power and occupational performances

PURPOSE

The effects of resistance training programs on strength, power, and military occupational task performances in women were examined.

METHODS

Untrained women aged (mean +/- SD) 23 +/- 4 yr were matched and randomly placed in total- (TP, N = 17 and TH, N = 18) or upper-body resistance training (UP, N = 18 and UH, N = 15), field (FLD, N = 14), or aerobic training groups (AER, N = 11). Two periodized resistance training programs (with supplemental aerobic training) emphasized explosive exercise movements using 3- to 8-RM training loads (TP, UP), whereas the other two emphasized slower exercise movements using 8- to 12-RM loads (TH, UH). The FLD group performed plyometric and partner exercises. Subjects were tested for body composition, strength, power, endurance, maximal and repetitive box lift, 2-mile loaded run, and U.S. Army Physical Fitness Tests before (T0) and after 3 (T3) and 6 months of training (T6). For comparison, untrained men (N = 100) (MEN) were tested once.

RESULTS

Specific training programs resulted in significant increases in body mass (TP), 1-RM squat (TP, TH, FLD), bench press (all except AER), high pull (TP), squat jump (TP, TH, FLD), bench throw (all except AER), squat endurance (all except AER), 1-RM box lift (all except aerobic), repetitive box lift (all), push-ups (all except AER), sit-ups (all except AER), and 2-mile run (all).

CONCLUSIONS

Strength training improved physical performances of women over 6 months and adaptations in strength, power, and endurance were specific to the subtle differences (e.g., exercise choice and speeds of exercise movement) in the resistance training programs (strength/power vs strength/hypertrophy). Upper- and total-body resistance training resulted in similar improvements in occupational task performances, especially in tasks that involved upper-body musculature. Finally, gender differences in physical performance measures were reduced after resistance training in women, which underscores the importance of such training for physically demanding occupations.

The Egyptian mongoose, Herpestes ichneumon, is a possible reservoir host of visceral leishmaniasis in eastern Sudan

Investigations were made on possible reservoir hosts of Leishmania donovani in 2 zoonotic foci of visceral leishmaniasis (VL) in Dinder National Park (DNP) and the peri-domestic habitats of adjacent villages of eastern Sudan. Animals were captured, in November 1997-1998 and April-May 1999 and examined for L. donovani infection using light microscopy and 2 sensitive Polymerase Chain Reaction (PCR) systems. Microscopy and PCR investigations were also used to determine the infection rates of L. donovani in Phlebotomus orientalis captured from the uninhabited site of DNP. Infections of L. donovani were detected in 2 out of 14 Egyptian mongooses (Herpestes ichneumon), 1 out of 168 Arviconthus niloticus and 1 out of 8 Mastomys natalensis. Samples from 68 other animals captured from the study area were all negative for the infection. Active zoonotic transmission of L. donovani at the time of animal sampling in the uninhabited site of DNP was demonstrated by finding the parasite in 3.4% (7 out of 184) and 3.2% (5 out of 157) of flies collected in March 1998 and May 1999, respectively. We suggest that the Egyptian mongoose is a possible reservoir host of L. donovani. The importance of other animals in maintaining the infection is also discussed.

Malaria vectors in the municipality of Serra do Navio, State of Amapá, Amazon Region, Brazil

We conducted a survey to determine the vectors of malaria in six localities of Serra do Navio municipality, State of Amapá, from 1990 to 1991. Malaria infection rates of 29.3%, 6.2% and 20.4% were detected by human blood smears in Colônia Agua Branca, Porto Terezinha and Arrependido, respectively. There was no malaria infection detected in Serra do Navio. Fifteen species were identified among 3,053 anopheline mosquitoes collected by human bait and 64.4% were identified as Anopheles albitarsis s.l., 16.7% An. braziliensis, 9.5% An. nuneztovari and 5.8% An. triannulatus. An. darlingi, the main vector of malaria in the Amazon region of Brazil, was scare. Using enzyme-linked immunosorbent assay (ELISA), a total positive rate of 0.8% (23/2876) was found for six species: fifteen An. albitarsis s.l., four An. nuneztovari, and one of each: An. braziliensis, An. triannulatus, An. oswaldoi and An. rangeli. Nine of 23 positive mosquitoes were infected with Plasmodium malariae, eight with P. vivax VK210, three with P. vivax VK247 and three with P. falciparum. Since An. albitarsis s.l. was collected feeding on humans, was present in the highest density and was positive by ELISA for malaria sporozoites, it probably plays an important role in malaria transmission in this area.

Genetic diversity and genetic exchange in Trypanosoma cruzi: dual drug-resistant "progeny" from episomal transformants

Extensive characterisation of Trypanosoma cruzi by isoenzyme phenotypes has separated the species into three principal zymodeme groups, Z1, Z2 and Z3, and into many individual zymodemes. There is marked diversity within Z2. A strong correlation has been demonstrated between the strain clusters determined by isoenzymes and those obtained using random amplified polymorphic DNA (RAPD) profiles. Polymorphisms in ribosomal RNA genes, in mini-exon genes, and microsatellite fingerprinting indicate the presence of at least two principal T. cruzi genetic lineages. Lineage 1 appears to correspond with Z2 and lineage 2 with Z1. Z1 (lineage 2) is associated with Didelphis. Z2 (lineage 1) may be associated with a primate host. Departures from Hardy-Weinberg equilibrium and linkage disequilibrium indicate that propagation of T. cruzi is predominantly clonal. Nevertheless, two studies show putative homozygotes and heterozygotes circulating sympatrically: the allozyme frequencies for phosphoglucomutase, and hybrid RAPD profiles suggest that genetic exchange may be a current phenomenon in some T. cruzi transmission cycles. We were able to isolate dual drug-resistant T. cruzi biological clones following copassage of putative parents carrying single episomal drug-resistant markers. A multiplex PCR confirmed that dual drug-resistant clones carried both episomal plasmids. Preliminary karyotype analysis suggests that recombination may not be confined to the extranuclear genome.

Secondary data analysis: new perspective for adolescent research

Adolescents are at high risk for preventable health problems, but realities of research funding and obtaining data from large samples make it difficult for many researchers to answer important questions. Secondary analysis of existing data sets is described as a reasonable alternative in spite of its limitations. Methods and available resources are identified along with suggestions for research priorities with adolescents.

The ecotopes and evolution of triatomine bugs (triatominae) and their associated trypanosomes

Triatomine bug species such as Microtriatoma trinidadensis, Eratyrus mucronatus, Belminus herreri, Panstrongylus lignarius, and Triatoma tibiamaculata are exquisitely adapted to specialist niches. This suggests a long evolutionary history, as well as the recent dramatic spread a few eclectic, domiciliated triatomine species. Virtually all species of the genus Rhodnius are primarily associated with palms. The genus Panstrongylus is predominantly associated with burrows and tree cavities and the genus Triatoma with terrestrial rocky habitats or rodent burrows. Two major sub-divisions have been defined within the species Trypanosoma cruzi, as T. cruzi 1 (Z1) and T. cruzi 2 (Z2). The affinities of a third group (Z3) are uncertain. Host and habitat associations lead us to propose that T. cruzi 1 (Z1) has evolved in an arboreal, palm tree habitat with the triatomine tribe Rhodniini, in association with the opossum Didelphis. Similarly we propose that T. cruzi (Z2) and Z3 evolved in a terrestrial habitat in burrows and in rocky locations with the triatomine tribe Triatomini, in association with edentates, and/or possibly ground dwelling marsupials. Both sub-divisions of T. cruzi may have been contemporary in South America up to 65 million years ago. Alternatively, T. cruzi 2 (Z2) may have evolved more recently from T. cruzi 1 (Z1) by host transfers into rodents, edentates, and primates. We have constructed a molecular phylogeny of haematophagous vectors, including triatomine bugs, which suggests that faecal transmission of trypanosomes may be the ancestral route. A molecular clock phylogeny suggests that Rhodnius and Triatoma diverged before the arrival, about 40 million years ago, of bats and rodents into South America.

Human chromosome structure studied by scanning force microscopy after an enzymatic digestion of the covering cell material

In standard preparations, metaphase human chromosomes are covered by a cell material film composed mainly of proteins and RNA. This film (approximately 30 nm thickness) hides the chromosome structure to the tip of a scanning force microscope. In this work, a mild enzymatic treatment is applied to remove the cell material film. After treatment, the individual chromatin fibers at the surface were resolved. Furthermore, the chromosome shows a thickness modulation, in which thicker/thinner regions could be associated with G/R bands. Finally, the topography of the chromosomes in solution is presented. The chromosome volume swelled about five-fold and chromatin packaging in bands and coils was observed.

Selective cleaning of the cell debris in human chromosome preparations studied by scanning force microscopy

The chromosome structure is one of most challenging biological structures to be discovered. Most evidence about the structure comes from optical microscopy. Scanning force microscopy (SFM) can achieve molecular resolution and allows imaging in liquids. However, little information about the chromosome structure has been revealed by SFM. In this work, a mild enzymatic treatment is applied to the chromosomes to remove selectively the RNA and proteins coming from the cell. The resulting SFM images indicate that a protein film with embedded RNA molecules covers chromosomes in standard cytogenetic preparations. The thickness of the protein layer is 15-35 nm and the RNA adheres preferentially to the chromosome surface. The cell material film results in a quite smooth chromosome surface without evidence of any structural detail. After treatment, the chromosome was cleaned from cell residues and individual chromatin fibers at the surface were resolved. Furthermore, insights about the higher order structure of the chromosome can be inferred.