共查询到20条相似文献,搜索用时 11 毫秒
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Venu M. Margam Brad S. Coates Malick N. Ba Weilin Sun Clementine L. Binso-Dabire Ibrahim Baoua Mohammad F. Ishiyaku John T. Shukle Richard L. Hellmich Fernando G. Covas Srinivasan Ramasamy Joel Armstrong Barry R. Pittendrigh Larry L. Murdock 《Molecular biology reports》2011,38(2):893-903
Maruca vitrata Fabricius is a pantropical lepidopteran pest of legumes. Phylogenetic analysis of a mitochondrial cytochrome c oxidase-I gene (cox1) fragment indicates that three Maruca sp. mitochondrial lineages have unique geographic distributions [lineages 1 and 2: Australia, Taiwan, and West Africa (Niger, Nigeria, and Burkina Faso), and lineage 3: Puerto Rico]. The haplotype (T30, T114) is specific to lineages 1&2 and was assayed by NsiI and SacI polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) within population samples; it was not observed in the Puerto Rican samples, but was nearly fixed among samples from West Africa, Australia and Taiwan (85.5?C100%). Re-sequencing and phylogenetic analyses of PCR-RFLP defined cox1 haplotypes indicate that nucleotide diversity is highest among samples from West Africa. Phylogenetic reconstruction based upon ribosomal DNA (rDNA) internal transcribed spacer-2 (ITS-2) sequences provided additional evidence for three Maruca sp. clades. These data suggest that multiple unique Maruca species or subspecies are present worldwide, which has implications for the management of this pest species-complex. 相似文献
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Amanda Veile Lauren Christopher Hugo Azcorra Federico Dickinson Karen Kramer Inês Varela-Silva 《American journal of physical anthropology》2022,178(2):205-222
Early-life conditions shape childhood growth and are affected by urbanization and the nutritional transition. To investigate how early-life conditions (across the “first” and “second” 1000 days) are associated with rural and urban children's nutritional status, we analyzed anthropometric data from Maya children in Yucatan, Mexico. We collected weight, height and triceps skinfold measures, then computed body mass and fat mass indices (BMI/FMI), in a cross-sectional sample of 6-year-olds (urban n = 72, rural n = 66). Demographic, socioeconomic and early-life variables (birthweight/mode, rural/urban residence, household crowding) were collected by maternal interview. We statistically analyzed rural-urban differences in demographic, socioeconomic, early-life, and anthropometric variables, then created linear mixed models to evaluate associations between early-life variables and child anthropometric outcomes. Two-way interactions were tested between early-life variables and child sex, and between early-life variables and rural-urban residence. Results showed that rural children were shorter-statured, with lower overweight/obesity and cesarean delivery rates, compared to urban children. Household crowding was a negative predictor of anthropometric outcomes; the strongest effect was in boys and in urban children. Birthweight positively predicted anthropometric outcomes, especially weight/BMI. Birth mode was positively (not statistically) associated with any anthropometric outcome. Cesarean delivery was more common in boys than in girls, and predicted increased height in urban boys. In conclusion, urbanization and household crowding were the most powerful predictors of Maya 6-year-old anthropometry. The negative effects of crowding may disproportionately affect Maya boys versus girls and urban versus rural children. Early-life conditions shape Maya children's nutritional status both in the “first” and “second” 1000 days. 相似文献
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Allatoregulatory peptides either inhibit (allatostatins) or stimulate (allatotropins) juvenile hormone (JH) synthesis by the corpora allata (CA) of insects. However, these peptides are pleitropic, the regulation of JH biosynthesis is not their only function. There are currently three allatostatin families (A-, B-, and C-type allatostatins) that inhibit JH biosynthesis, and two structurally unrelated allatotropins. The C-type allatostatin, characterised by its blocked N-terminus and a disulphide bridge between its two cysteine residues, was originally isolated from Manduca sexta. This peptide exists only in a single from in Lepidoptera and is the only peptide that has been shown to inhibit JH synthesis by the CA in vitro in this group of insects. The C-type allatostatin also inhibits spontaneous contractions of the foregut. The A-type allatostatins, which exist in multiple forms in a single insect, have also been characterised from Lepidoptera. This family of peptides does not appear to have any regulatory effect on JH biosynthesis, but does inhibit foregut muscle contractions. Two structurally unrelated allatotropins stimulate JH biosynthesis in Lepidoptera. The first was identified in M. sexta (Manse-AT) and occurs in other moths. The second (Spofr AT2) has only been identified in Spodoptera frugiperda. Manduca sexta allatotropin also stimulates heart muscle contractions and gut peristalsis, and inhibits ion transport across the midgut of larval M. sexta. The C-terminal (amide) pentapeptide of Manse-AT is important for JH biosynthesis activity. The most active conformation of Manse-AS requires the disulphide bridge, although the aromatic residues also have a significant effect on biological activity. Both A- and C-type allatostatins and Manse-AT are localised in neurosecretory cells of the brain and are present in the corpora cardiaca, CA and ventral nerve cord, although variations in localisation exist in different moths and at different stages of development. The presence of Manse-AS and Manse-AT in the CA correlates with the biological activity of these peptides on JH biosynthesis. There is currently no explanation for the presence of A-type allatostatins in the CA. The three peptide types are also co-localised in neurosecretory cells of the frontal ganglion, and are present in the recurrent nerve that supplies the muscles of the gut, particularly the crop and stomodeal valve, in agreement with their role in the regulation of gut peristalsis. There is also evidence that they are expressed in the midgut and reproductive tissues. 相似文献
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Desmond H. Foley Yvonne‐Marie Linton J. Freddy Ruiz‐Lopez Jan E. Conn Maria Anice M. Sallum Marinete M. Póvoa Eduardo S. Bergo Tatiane M. P. Oliveira Izis Sucupira Richard C. Wilkerson 《Journal of vector ecology》2014,39(1):168-181
The Anopheles albitarsis group of mosquitoes comprises eight recognized species and one mitochondrial lineage. Our knowledge of malaria vectorial importance and the distribution and evolution of these taxa is incomplete. We constructed ecological niche models (ENMs) for these taxa and used hypothesized phylogenetic relationships and ENMs to investigate environmental and ecological divergence associated with speciation events. Two major clades were identified, one north (Clade 1) and one south (Clade 2) of the Amazon River that likely is or was a barrier to mosquito movement. Clade 1 species occur more often in higher average temperature locations than Clade 2 species, and taxon splits within Clade 1 corresponded with a greater divergence of variables related to precipitation than was the case within Clade 2. Comparison of the ecological profiles of sympatric species and sister species support the idea that phylogenetic proximity is related to ecological similarity. Anopheles albitarsis I, An. janconnae, and An. marajoara ENMs had the highest percentage of their predicted suitable habitat overlapping distribution models of Plasmodium falciparum and P. vivax, and warrant additional studies of the transmission potential of these species. Phylogenetic proximity may be related to malaria vectorial importance within the Albitarsis Group. 相似文献
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Juan Eugenio Hernández-ávila Mario-Henry Rodríguez René Santos-Luna Veronica Sánchez-Casta?eda Susana Román-Pérez Víctor Hugo Ríos-Salgado Jesús Alberto Salas-Sarmiento 《PloS one》2013,8(8)
Dengue fever incidence and its geographical distribution are increasing throughout the world. Quality and timely information is essential for its prevention and control. A web based, geographically enabled, dengue integral surveillance system (Dengue-GIS) was developed for the nation-wide collection, integration, analysis and reporting of geo-referenced epidemiologic, entomologic, and control interventions data. Consensus in the design and practical operation of the system was a key factor for its acceptance. Working with information systems already implemented as a starting point facilitated its acceptance by officials and operative personnel. Dengue-GIS provides the geographical detail needed to plan, asses and evaluate the impact of control activities. The system is beginning to be adopted as a knowledge base by vector control programs. It is used to generate evidence on impact and cost-effectiveness of control activities, promoting the use of information for decision making at all levels of the vector control program. Dengue-GIS has also been used as a hypothesis generator for the academic community. This GIS-based model system for dengue surveillance and the experience gathered during its development and implementation could be useful in other dengue endemic countries and extended to other infectious or chronic diseases. 相似文献
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André Briend Bogdan Wojtyniak Michael G M Rowland 《BMJ (Clinical research ed.)》1988,296(6626):879-882
The effect of breast feeding on nutritional state, morbidity, and child survival was examined prospectively in a community in rural Bangladesh. Every month for six months health workers inquired about breast feeding and illness and measured arm circumference in an average of 4612 children aged 12-36 months. Data from children who died within one month of a visit were compared with those from children who survived. Roughly one third of the deaths in the age range 18-36 months were attributable to absence of breast feeding. Within this age range protection conferred by breast feeding was independent of age but was evident only in severely malnourished children.In communities with a high prevalence of malnutrition breast feeding may substantially enhance child survival up to 3 years of age. 相似文献
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Fiona J. Qualls Richard Shine 《Biological journal of the Linnean Society. Linnean Society of London》1998,64(4):477-491
Geographic variation in phenotypes can result from proximate environmental effects as well as from underlying genetic factors. Reciprocal transplant experiments, in which organisms are moved from one area to another, offer a powerful technique to partition the effects of these two factors. However, many studies that have utilized this technique have focused on the post-hatching organism only and ignored potential effects of environmental influences acting during embryonic development. We examined the phenotypic responses of hatchling scincid lizards ( Lampropholis guichenoti ) incubated in the laboratory under thermal regimes characteristic of natural nests in two study areas in southeastern Australia. Although the sites were less than 120 km apart, lizards from these two areas differed in thermal regimes of natural nests, and in hatchling phenotypes (morphology, locomotor performance). We incubated eggs from each area under the thermal regimes typical of both sites. Some of the traits we measured (e.g. hatchling mass and snout-vent length) showed little or no phenotypic plasticity in response to differences in incubation conditions, whereas other traits (e.g. incubation period, tail length, inter-limb length, body shape, locomotor performance) were strongly influenced by the thermal regime experienced by the embryo. Thus, a significant proportion of the geographic variation in morphology and locomotor performance of hatchling lizards may be directly induced by differences in nest temperatures rather than by genetic divergence. We suggest that future studies using the reciprocal transplant design should consider environmental influences on all stages of the life-history, including embryonic development as well as post-hatching life. 相似文献
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The host selection for oviposition by Spodoptera frugiperda (J.E. Smith) among corn, millet, cotton and soybean, and its relationship with the biological characteristics were investigated. Free and non-choice tests for oviposition using plots containing five plants each, from each host in plastic greenhouse, resulted in similar oviposition preference among the host plants. In addition, selected biological characteristics of S. frugiperda were determined in the laboratory with larvae feeding on host leaves, and the combination of leaf and cotton boll. Neonate larvae exhibited low success of colonization on cotton boll compared to the leaves of all other hosts. Spodoptera frugiperda fed only on cotton bolls exhibited longer larval and pupal development, and longer adult life span; however with similar egg production. Larvae fed cotton leaves during six days and then transferred to cotton bolls, however, exhibited development and reproduction similar to those reared on corn or only on cotton leaves. Therefore, the variations on immature stages of S. frugiperda were not related with host selection for oviposition which was similar among the studied hosts. Based on our data, the millet as a winter, rotational, and cover crop is a potential host for S. frugiperda, while leaves and cotton bolls were diets of intermediate suitability as compared to corn and soybean leaves. 相似文献
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We examine the impacts of weather shocks, defined as rainfall or growing degree days, a cumulative measure of temperature, more than a standard deviation from their respective long run mean, on the stature of children between 12 and 47 months of age in Mexico. We find that after a positive rainfall shock children are shorter regardless of their region or altitude. Negative temperature shocks have a negative impact on height in the central and southern parts of the country as well as in higher altitudes. Although on average there are no statistically significant impacts from positive temperature shocks, certain sub-populations - namely boys, children between 12 and 23 months at the time of measurement, and children of less educated mothers - in some of the regions are negatively impacted. The results also suggest that potentially both agricultural income and communicable disease prevalence contribute to the effects. 相似文献
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Fei Qin Xiao-Xia Zhang Yun-Feng Huang Lei Wu Wei-Bin Xu Tian-Tian Xue Wen-Di Zhang Qin Liu Jiang-Hong Yu Jie-Jing Gao Rainer W. Bussmann Juan Wang Sheng-Xiang Yu 《植物分类学报:英文版》2023,61(6):967-978
National key protected wild plants (NKPWPs) are species with important conservation value based on genetics, ecology, culture, and/or scientific research, which are also confronted with serious threats. However, their geographical distribution patterns and conservation status remain unclear. In this study, we compiled 1032 species of NKPWPs. We measured the diversity to identify hotspots of NKPWPs based on species richness, weighted range size rarity and a complementarity-based analysis. Comparing the distribution and hotspots of NKPWPs with the coverage of Chinese nature reserves (NRs), we assessed conservation effectiveness and identified conservation gaps. The results identified 13 diversity hotspots; only 9.5% of them were covered by NRs with >30% of the grid cell area, and even 19.5% were not covered at all by NRs. Overall, 44.7% of NKPWPs were effectively protected by national NRs. Despite this success, 571 species in Yunnan, Guizhou, Sichuan, Chongqing, Guangxi, Guangdong, southern Hainan, Taiwan, and northern Xinjiang remain unprotected by NRs. The protected proportion of plants with first-level protection was lower than that of plants with second-level protection. The low overall proportion of protected hotspots indicates that the conservation outlook for NKPWPs is not optimistic. This study identifies priority conservation areas and conservation gaps and provides a scientific reference for the conservation of wild plants in China. 相似文献
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T. R. Stanton 《Economic botany》1953,7(1):43-64
Oats constitute an important feed grain crop in the United States and many other countries. World production in pounds averages one- third that of wheat and two- fifths that of rice or corn. The United States and Canada produce nearly half of the world crop. Oats are utilized primarily as feed for domestic animals. Although their bone- and muscle- building ingredients and other nutrient values are well known, less than five percent of the world crop is used as human food. 相似文献
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Geographic variation in diapause induction: the grape berry moth (Lepidoptera: Tortricidae) 总被引:1,自引:0,他引:1
Diapause in insects occurs in response to environmental cues, such as changes in photoperiod, and it is a major adaptation by which insects synchronize their activity with biotic resources and environmental constraints. For multivoltine agricultural insect pests, diapause initiation is an important consideration in management decisions, particularly toward the end of the growing season. The grape berry moth, Paralobesia viteana (Clemens), is the main insect pest affecting viticulture, and this insect responds to postsummer solstice photoperiods to initiate diapause. Because the range of grape berry moth extends from southern Canada to the southern United States, different populations are exposed to different photoperiodic regimes. We quantified the diapause response in grape berry moth populations from Arkansas, Michigan, New York, Pennsylvania, Texas, and Virginia, and observed latitudinal variation in diapause initiation. Populations from Michigan, New York, and Pennsylvania responded significantly different than those from Arkansas, Texas, and Virginia. We also observed, as a consequence of our experiments, that the timing of our laboratory studies influenced grape berry moth's response to photoperiod, ceteris paribus. Experiments that were conducted when grape berry moth would be naturally in diapause resulted in a significant higher proportion of diapausing pupae at photoperiods (i.e., >15 h) that generally do not induce diapause, suggesting that attention should be paid to the timing of behavioral and physiological experiments on insects. This relationship between photoperiod and diapause induction in grape berry moth across geographic regions will provide applicable knowledge to improve pest management decisions. 相似文献
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Little BB Buschang PH Peña Reyes ME Tan SK Malina RM 《American journal of physical anthropology》2006,131(1):127-136
The objective of this investigation was to analyze the underlying cause(s) of secular changes in craniofacial dimensions among indigenous children in an isolated community in Oaxaca, southern Mexico, between 1968-2000. Subjects were schoolchildren resident in a rural, agrarian, Zapotec-speaking community in the Valley of Oaxaca, previously characterized as mildly-to-moderately undernourished with growth-stunting in 1968 and 1978. In 2000, children had experienced a secular increase in height compared with two prior growth surveys. Four craniofacial dimensions (head length, head breadth, and bizygomatic and bigonial breadths) were measured during anthropometric surveys of schoolchildren aged 6-13 years in 1968, 1978, and 2000. Cephalic and zygomandibular indices were calculated. Samples by survey were: 1968, 151 males and 157 females; 1978, 179 males and 184 females; and 2000, 180 males and 186 females. The analysis was based on a total of 1,037 children. Multivariate analysis of covariance was used to assess secular trend effects, with height, age, and age2 as covariates by sex. Over the interval of 32 years, significant secular changes occurred in craniofacial dimensions and one index: 1) head length was shorter in boys and girls; 2) bizygomatic breadth was narrower in boys and girls; 3) head breadth increased over time only among girls; 4) brachycephalization increased significantly in a linear manner among both sexes; and 5) the zygomandibular index decreased significantly only in boys. Thus, the cranial complex remodeled to a shorter head length, both relatively (brachycephalization) and absolutely. Remodeling over time also resulted in a narrower face, with the midface changing at about the same rate as the lower face (i.e., mandible). Secular changes are generally recognized as multifactorial. Changes in the cephalic index and cranium over time in schoolchildren in an isolated rural agrarian Zapotec-speaking community in the Valley of Oaxaca suggest that the underlying forces for the secular change are associated: 1) decreased food (maize) coarseness or grit content (masticatory stress), and 2) relaxed natural selection, resulting in 3) a greater role for developmental plasticity. 相似文献
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The distribution of subcutaneous fat at the triceps and subscapular skinfold sites is described for four groups of children living in Guatemala. These groups are high socioeconomic status (SES) children of Ladino (mixed Spanish and Indian) ancestry, high SES children of European ancestry, low SES Ladino children, and very low SES Indian children. The method of Healy and Tanner (1981) is used, employing regression and principal components analysis of log transformed skinfold values to divide "fatness" into two uncorrelated variables: size (amount of fat) and shape (fat pattern). Significant differences exist between groups in size, with lower SES groups having less fat than higher SES groups. No significant difference in fat pattern exists between the high SES Ladino and high SES European children. Significant differences do exist between the high SES groups and the low SES groups. The relative amount of subscapular fat increases from the high SES Ladinos and high SES Europeans, to the low SES Ladinos, to the very low SES Indians. In the high SES European and high SES Ladino samples, girls have significantly more arm fat than boys. There is no significant difference in fat patterning between boys and girls in the two low SES samples. Finally, the relative amount of subscapular fat tends to increase with age in all four samples. These results indicate that fatness and fat patterning are independent anatomical characteristics, SES influences fat patterning; low SES children of both Ladino and Indian ancestry show greater reductions in arm fat than in trunk fat compared to high SES children, sexual dimorphism in fat patterning is SES dependent.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献