articles+ search results

PREDATION, REPRODUCTION, LONGEVITY, and ECOLOGY

Reproduction and longevity of Podisus restralis (Stil) (Heteroptera:Pentatomidae) females, fed at different intervals were studied in the 'Nucleo de Biotecnologia Aplicada A Agropecuaria' (BIOAGRO), of the'Universidade Federal de Vigosa' (UFV), in Viqosa, Minas Gerais, Brazil, at 25 t 2 deg. C, 70 t 1096 R.H. and photophase of 12 hours. Females of P. rostralis were fed with Tenebrio molitor L. (Coleoptera: Tenebrionidae) larva, during 24 hours, every one, two, four, eight and16 days. An inverse linear effect was found between oviposition period, egg batches/female, total number and number of eggs per day with feeding interval. Daily fed females laid more eggs (199.6) while those fed every 16 days showed lowest number of eggs (45.3). Longevity ofP. rostralis was similar in all feeding intervals. Egg oviposition rate was reduced but females of this predator maintained its longevitywhich give then higher chances to maintain themselves in the ecosystem until occurs better conditions of preys. [ABSTRACT FROM AUTHOR]

Striated craniofacial and limb muscles differ in their embryological origin, regulatory program during myogenesis, and innervation. In an attempt to explore the effects of these differences on the striated muscle phenotype in humans, the expression of myosin and myosin-associated thick filament proteins were studied at the single fiber level both in the human jaw-closing masseter muscle and in two limb muscles (biceps brachii and quadriceps femoris muscles). In the masseter, unique combinations of myosin heavy chain (MyHC) and myosin binding protein C (MyBP-C) isoforms were observed at the single fiber level. Compared to the limb muscles, the MyHC isoform expression was more complex in the masseter while the opposite was observed for MyBP-C. In limb muscles, a coordinated expression of three MyHC and three MyBP-C isoforms were observed, i.e., single fibers contained one or two MyHC isoforms, and up to three MyBP-C isoforms. Also, the relative content of the different MyBP-C isoforms correlated with the MyHC isoform expression. In the masseter, on the other hand, up to five different MyHC isoforms could be observed in the same fiber, but only one MyBP-C isoform was identified irrespective MyHC isoform expression. This MyBP-C isoform had a migration rate similar to the slow MyBP-C isoform in limb muscle fibers. In conclusion, a unique myofibrillar protein isoform expression was observed in the human masseter muscle fibers, suggesting significant differences in structural and functional properties between muscle fibers from human masseter and limb muscles. [ABSTRACT FROM AUTHOR]

TONGUE, MORPHOLOGY, COMPARATIVE anatomy, MUSCLES, and MOUTH

The muscle fibre composition of three human intrinsic tongue muscles, the longitudinalis, verticalis and transversus, was investigated in four anterior to posterior regions of the tongue using morphological and enzyme- and immunohistochemical techniques. All three muscles typically contained type I, IIA and IM/IIC fibres. Type I fibres expressed slow myosin heavy chain (MyHC), type II fibres fast MyHC, mainly fast A MyHC, whereas type IM/IIC coexpressed slow and fast MyHCs. Type II fibres were in the majority (60%), but regional differences in proportion and diameter of fibre types were obvious. The anterior region of the tongue contained a predominance of relatively small type II fibres (71%), in contrast to the posterior region which instead showed a majority of larger type I and type IM/IIC fibres (66%). In general, the fibre diameter was larger in the posterior region. This muscle fibre composition of the tongue differs from those of limb, orofacial and masticatory muscles, probably reflecting genotypic as well as phenotypic functional specialization in oral function. The predominance of type II fibres and the regional differences in fibre composition, together with intricate muscle structure, suggest generally fast and flexible actions in positioning and shaping the tongue, during vital tasks such as mastication, swallowing, respiration and speech.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

PLANT chemical defenses, VIGNA, and COREIDAE

The effects of secondary metabolites in different Vigna species on the development of Clavigralla tomentosicollis were investigated in an artificial seed system using different fractions of crude pod extracts, while the orientation response of this pod-bug to volatile extracts was studied using a dual-choice olfactometer. Feeding on the neutral fraction extracts, in contrast to the basic and acidic fractions, resulted in significantly higher mortalities, longer total developmental time, and lower growth index of the insects in comparison with controls. All volatile extracts elicited an avoidance reaction by C. tomentosicollis, except the volatile from the susceptible genotype IT84S-2246 which generally attracted as many insects as controls. Extracts from wild Vigna species showed higher activity than those from their cultivated relatives. The present study which has established that most secondary metabolites in cowpea pods were localized in the neutral fraction of the crude extract, could facilitate experiments on the separation and characterization of the toxic factors involved. [ABSTRACT FROM AUTHOR]

COWPEA, LEGUMES, DEFOLIATION, PLANT canopies, SEED disinfection, EFFECT of temperature on plants, and PHYSIOLOGICAL effects of temperature

Pottedcowpea, Vigna unguiculata (L.) Walp., plants were used to determine the effects of defoliation and pod position relative to the leaf canopy on infestation and damage by the coreid pod-bugs Clavigralla tomentosicollis Stål and Anoplocnemis curvipes (F.). Temperature measurements were taken within and outside the canopy to determine whether there was a correlation to seed damage. Seed damage decreased significantly with increasing defoliation in plants infested with C. tomentosicollis; an inverse trend was observed with A. curvipes. Temperatures within the canopy increased as the number of leaves decreased. As observed in the defoliation experiment, C. tomentosicollis and A. curvipes reacted differently in a free-choice situation between pods located outside or within the canopy. Significantly higher numbers of C. tomentosicollis concealed themselves within the canopy, where they caused more severe damage to seeds, in comparison with numbers and damage outside the canopy. These trends were reversed for A. curvipes. There was a significant negative correlation between percentage of seed damage and temperature with C. tomentosicollis, and a significant positive correlation with A. curvipes, both in defoliated plants and those with pods distributed outside and within the canopy. Overall, plants with less dense canopy, and long peduncles holding pods outside the canopy showed some resistance to C. tomentosicollis, which is the most damaging pod bug on cowpea. Because such cowpea plants harbor fewer C. tomentosicollis, they are likely to suffer less overall damage from infestation by the complex of pod bugs that occur concurrently in cowpea fields. [ABSTRACT FROM AUTHOR]

BREAST cancer, CANCER in women, CANCER treatment, THERAPEUTICS, TAMOXIFEN, TUMOR growth, and ESTROGEN

Background: Subgroups of breast cancer that have an impaired response to endocrine treatment, despite hormone receptor positivily, are still poorly defined. Breast cancer can be subdivided according to standard pathological parameters including histological type, grade, and assessment of proliferation. These parameters are the net result of combinations of genetic alterations effecting tumour behaviour and could potentially reflect subtypes that respond differently to endocrine treatment. Aims: To investigate the usefulness of these parameters as predictors of the response to tamoxifen in premenopausal women with breast cancer. Materials/methods: Clinically established pathological parameters were assessed and related to the tamoxifen response in 500 available tumour specimens from 564 premenopausal patients with breast cancer randomised to either two years of tamoxifen or no treatment with 14 years of follow up. Proliferation was further evaluated by immunohistochemical Ki-67 expression. Results: Oestrogen receptor positive ductal carcinomas responded as expected to tamoxifen, whereas the difference in recurrence free survival between control and tamoxifen treated patients was less apparent in the relatively few lobular carcinomas. For histological grade, there was no obvious difference in treatment response between the groups. The relation between proliferation and tamoxifen response seemed to be more complex, with a clear response in tumours with high and low proliferation, whereas tumours with intermediate proliferation defined by Ki-67 responded more poorly. Conclusions: Clinically established pathology parameters seem to mirror the endocrine treatment response and could potentially be valuable in future treatment decisions for patients with breast cancer. [ABSTRACT FROM AUTHOR]

ETHYLENE glycol, THERMODYNAMICS, HYDROGEN bonding, SUPRAMOLECULAR chemistry, SOLVENTS, and CHEMICAL reduction

Substitution of hydrogen bond directed supramolecular assemblies with ethylene glycol chains leads to a reduction in the association constant in apolar solvents, where the reduction of the association constant is dependent on the length of the aliphatic spacer connecting the hydrogen bonds and the ethylene glycol chain. [ABSTRACT FROM AUTHOR]

COMPARTMENT syndrome, FASCIAE surgery, THERAPEUTICS, ANALYSIS of variance, CAPILLARIES, CHI-squared test, COMPUTER software, EXERCISE, IMMUNOHISTOCHEMISTRY, LEG, LONGITUDINAL method, MICROCIRCULATION, MUSCLES, RESEARCH funding, STRIATED muscle, T-test (Statistics), DATA analysis, CASE-control method, ANALYTICAL chemistry, PATHOLOGY, and DONOR blood supply

There is a paucity of data regarding the pathogenesis of chronic exertional compartment syndrome (CECS), its consequences for the muscles and the effects of treatment with fasciotomy. We analyzed biopsies from the tibialis anterior muscle, from nine patients, obtained during a decompressing fasciotomy and during follow-up 1 year later. Control biopsies were obtained from nine normal subjects. Muscle capillarity, fiber-type composition and fiber area were analyzed with enzyme- and immunohistochemistry and morphometry. At baseline, CECS patients had lower capillary density (273 vs 378 capillaries/mm, P=0.008), lower number of capillaries around muscle fibers (4.5 vs 5.7, P=0.004) and lower number of capillaries in relation to the muscle fiber area (1.1 vs 1.5, P=0.01) compared with normal controls. The fiber-type composition and fiber area did not differ, but focal signs of neuromuscular damage were observed in the CECS samples. At 1-year follow-up after fasciotomy, the fiber area and the number of fibers containing developmental myosin heavy chains were increased, but no enhancement of the capillary network was detected. Thus, morphologically, patients with CECS seemed to have reduced microcirculation capacity. Fasciotomy appeared to trigger a regenerative response in the muscle, however, without any increase in the capillary bed. [ABSTRACT FROM AUTHOR]

EXITIANUS, CORN diseases, LEAFHOPPERS, and INSECTS

"Corn stunt" caused by the mollicute Spiroplasma kunkelii (Whitcomb) is potentially one of the most severe diseases affecting the corn (Zea mays L.) crop in the Americas, and the leafhopper Dalbulus maidis (DeLong & Wolcott) is considered its most important vector. However, other insects seen quite frequently in corn crops might well be its vectors in Argentina. To identify any leafhoppers species other than D. maidis that can transmit S. kunkelii, transmission assays were conducted, using individuals of Exitianus obscurinervis (Stål) collected in field and reared under controlled conditions. S. kunkelii was transmitted to corn plants by E. obscurirwrvis. The pathogen was transmitted to seven of the 11 plants, which showed characteristic corn stunt symptoms, and the presence of the pathogen was confirmed by DAS-ELISA. The presence of S. kunkelii in the E. obscurinervis individuals used in transmission experiments was confirmed by polymerase chain reaction and electron microscopy. The current study shows the existence of a new experimental vector of S. kunkelii, the leafhopper E. obscurinervis, which acquired spiroplasmas from infected plants and inoculated it to healthy plants. [ABSTRACT FROM AUTHOR]