Trypanosoma cruzi (Kinetoplastida Trypanosomatidae): ecology of the transmission cycle in the wild environment of the Andean valley of Cochabamba, Bolivia

An active Trypanosoma cruzi transmission cycle maintained by wild rodents in the Andean valleys of Cochabamba Bolivia is described. Wild and domestic Triatoma infestans with 60% infection with T. cruzi were found and was evidenced in 47.5% (rodents) and 26.7% (marsupial) by parasitological and/or serologycal methods. Phyllotis ocilae and the marsupial species Thylamys elegans, are the most important reservoirs followed by Bolomys lactens and Akodon boliviensis. In spite of both genotypes (TCI and TCII) being prevalent in Bolivia, in our study area only T. cruzi I is being transmitted. Our data suggest that wild T. infestans and wild small mammals play an important role in the maintenance of the transmission cycle of T. cruzi. Furthermore, the finding of high prevalence of T. cruzi infection in wild T. infestans point to the risk of the dispersion of Chagas' disease.     

Ammonium formation and assimilation in P(SARK)∷IPT tobacco transgenic plants under low N

Wild Type (WT) and transgenic tobacco plants expressing isopentenyltransferase (IPT), a gene encoding the enzyme regulating the rate-limiting step in cytokinins (CKs) synthesis, were grown under limited nitrogen (N) conditions. We analyzed nitrogen forms, nitrogen metabolism related-enzymes, amino acids and photorespiration related-enzymes in WT and P_SARK∷IPT tobacco plants. Our results indicate that the WT plants subjected to N deficiency displayed reduced nitrate (NO₃⁻) assimilation. However, an increase in the production of ammonium (NH₄⁺), by the degradation of proteins and photorespiration led to an increase in the glutamine synthetase/glutamate synthase (GS/GOGAT) cycle in WT plants. In these plants, the amounts of amino acids decreased with N deficiency, although the relative amounts of glutamate and glutamine increased with N deficiency. Although the transgenic plants expressing P_SARK∷IPT and growing under suboptimal N conditions displayed a significant decline in the N forms in the leaf, they maintained the GS/GOGAT cycle at control levels. Our results suggest that, under N deficiency, CKs prevented the generation and assimilation of NH₄⁺ by increasing such processes as photorespiration, protein degradation, the GS/GOGAT cycle, and the formation of glutamine.     

山西云顶山自然保护区野生种子植物区系研究

山西云顶山自然保护区位于吕梁山脉中段,有野生种子植物926种,隶属于391属、85科,其中裸子植物2科、4属、6种,被子植物83科、387属、920种(其中双子叶植物72科、311属、756种;单子叶植物11科、76属、164种).种子植物属的区系成分复杂多样,以温带成分占绝对优势,温带属共275属,占总属数的82.08％.种子植物种的区系成分中,温带分布占绝对优势,达566种,占总种数的62.61％,中国特有分布次之,有306种,它们是构成云顶山自然保护区森林植被和灌丛植被的建群种和优势种的主要成分.经与有关山地植物区系和植被组成比较后得出,云顶山自然保护区与庞泉沟自然保护区具有较高的同质性和密切的联系,与五台山次之,而与中条山具有明显的差异.云顶山自然保护区有国家二级保护植物野大豆,还有山西省重点保护植物山西乌头、红景天和党参3种.     

四川及其周边地区野生草莓资源调查、收集与评价

调查了四川及其周边地区(未包括青海省)野生草莓资源种类和地理分布,将收集的野生草莓资源进行迁地保存,并对其农艺性状、抗非生物和生物胁迫能力的变异进行了主成分分析。结果表明,四川及其邻近周边高海拔地区野生草莓主要分布在26°14’～33°22’N、96°57’～108°13’E、海拔823～4531m的垂直空间范围内。黄毛草莓(Fragaria nilgerrensisSchlecht.)、五叶草莓(F.pentaphylla Lozinsk.)、西南草莓(F.moupinensis(Franch.)Card.)和纤细草莓(F.gracilis Lozinsk.)是该区域分布的4个野生草莓种类,其中五叶草莓有红果和白果两个类型。黄毛草莓浆果具有特殊的蜜桃香气。株高、叶柄长度、小叶长度、小叶宽度、茸毛、耐旱性和耐热性是野生草莓遗传性状的主要指标,茸毛数量与抗逆性密切相关。     

甘肃康县野生珍稀食用菌资源应用开发前景与展望

从野生珍稀食用菌方面综述了康县食用菌的资源状况,通过对康县野生珍稀食用菌研究、开发现状的总结,就其存在的问题提出了相应的建议。简述了野生珍稀食用菌资源在康县应用开发中的广阔前景。     

Meta-analysis of the effect of immunocastration on production performance,reproductive organs and boar taint compounds in pigs

Meta-analytical approach was used to quantitatively synthesize the effect of immunocastration on growth, carcass, meat quality, reproductive organs and boar taint compounds. Altogether, 41 papers were collected for effect size (θ) calculation and the comparisons were made with entire males (EM) and surgical castrates (SC). The data for reproductive organs and growth performance are numerous enough to draw firm conclusions. In contrast, data for carcass and meat quality are more limited. Results of meta-analysis show efficient immunocastration with the magnitude of the response being by far the largest for reproductive organs (θ = −2.8 to −5.0) and boar taint substances (θ = −2.8 and −0.8 for androstenone and skatole, respectively). However, compared with SC, the immunocastrates exhibit larger bulbourethral glands (θ = 1.3) and slightly higher concentrations of androstenone and skatole (θ = 0.1 and θ = 0.2, respectively). The impact of immunocastration is also remarkable on performance, where the main advantage of the immunocastrates is their boar-like performance until revaccination. In the period following the second vaccination, they eat much more than EM (θ = 2.1), resulting in large effect size for growth rate compared with both EM and SC (θ = 1.1 and θ = 1.4, respectively). Considering the whole fattening period, their feed conversion ratio is higher compared with EM (θ = 0.6) and much lower than that of SC (θ = −1.3), although exhibiting moderately faster growth compared with both (θ = 0.6 and θ = 0.2, respectively). With regard to carcass quality, the immunocastrates take intermediate position between EM and SC. Besides, our analysis suggests no difference in meat quality with SC and some meat quality advantages of immunocastrates over EM because of higher intramuscular fat content (θ = 0.4) and lower shear force (θ = −0.6).     

A mortality survey of free range nutria (Myocastor coypus)

A review of the literature revealed little information on natural occurring diseases in wild nutria. In this report, a summary of necropsies performed on free-range animals from four different geographical areas, is presented. Fifty-two percent of the nutria had trauma (mostly by predation and road kill), 15% had poisoning by different toxics, and 11% had starvation. The rest died due to infectious diseases and miscellaneous causes, while 21 individuals had no significant lesions. The occurrence of infections seems sporadic with a far lower prevalence than in the farmed animals, while the incidence of poisoning is rather high. In addition, anthrax was diagnosed in two individuals. Thus, nutria are probably subject to mortality from a number of different human-induced causes rather than natural ones. Analysis of these records may provide insight into prevention of problem and better management practices.     

Resprouting of <Emphasis Type="Italic">Echinacea angustifolia</Emphasis> Augments Sustainability of Wild Medicinal Plant Populations

Resprouting of Echinacea angustifolia Augments Sustainability of Wild Medicinal Plant Populations. Overharvest of wild Echinacea species root has been a significant concern to the herbal industry. Harvesters of wild Echinacea angustifolia showed us that even after harvesting the top 15 to 20 cm of root, some plants resprout. We marked locations of harvested plants at sites in Kansas and Montana and reexamined them two years later to see if they resprouted from remaining root reserves. Approximately 50% of the roots resprouted at both Kansas and Montana sampling sites, despite droughty weather conditions in Montana. The length of root harvested significantly affected the ability of the plant to resprout. Those plants that were more shallowly harvested and had less root length removed were more likely to resprout. These data indicate that echinacea stands can recover over time from intensive harvest if periods of nonharvest occur. Our echinacea harvest study emphasizes that the entire biology of medicinal plants must be considered when evaluating their conservation status.     

Simple sequence repeat analyses of interspecific hybrids and MAALs of <Emphasis Type="Italic">Oryza </Emphasis><Emphasis Type="Italic">officinalis</Emphasis> and <Emphasis Type="Italic">Oryza sativa</Emphasis>

Wild rice is a valuable resource for the genetic improvement of cultivated rice (Oryza sativa L., AA genome). Molecular markers are important tools for monitoring gene introgression from wild rice into cultivated rice. In this study, Simple sequence repeat (SSR) markers were used to analyze interspecific hybrids of O. sativa-O. officinalis (CC genome), the backcrossing progenies and the parent plants. Results showed that most of the SSR primers (335 out of 396, 84.6%) developed in cultivated rice successfully amplified products from DNA samples of wild rice O. officinalis. The polymorphism ratio of SSR bands between O. sativa and O. officinalis was as high as 93.9%, indicating differences between the two species with respect to SSRs. When the SSR markers were applied in the interspecific hybrids, only a portion of SSR primers amplified O. officinalis-specific bands in the F(1) hybrid (52.5%), BC(1) (52.5%), and MAALs (37.0%); a number of the bands disappeared. Of the 124 SSR loci that detected officinalis-specific bands in MAAL plants, 96 (77.4%) showed synteny between the A and C-genomes, and 20 (16.1%) showed duplication in the C-genome. Sequencing analysis revealed that indels, substitution and duplication contribute to the diversity of SSR loci between the genomes of O. sativa and O. officinalis.     

Early Holocene cultivation before domestication in northern Syria

Charred plant remains from the sites of Tell Qaramel, Jerf el Ahmar, Dja’de and Tell ‘Abr situated in northern Syria and dated to the tenth and ninth millennia cal b.c. demonstrate that a wide variety of wild pulses, cereals, fruits and nuts was exploited. Five lines of evidence suggest that cultivation was practised at three of the sites. (1) Wild einkorn, wild rye and lentils occur outside their natural habitats. (2) The founder crops barley, emmer and single-grained einkorn appear at different times. (3) An assemblage of weeds of cultivation was identified. (4) There is a gradual decrease in gathered plants such as small seeded grasses and Polygonum/Rumex. (5) Barley grains increase in breadth and thickness. Morphological domestication did not become established, perhaps because seed stock was regularly collected from wild stands. Charred rodent droppings indicate large-scale grain storage.