A new stain for identification of avian leukocytes

Differential staining of avian leukocytes was achieved within 6 min following brief fixation in a methanolic solution of C.I. acid red 360 followed by immersion in a mixture containing C.I. basic blue 41, C.I. basic blue 141, and C.I. acid red 52. Heterophils contained black angular and punctate granules. Eosinophils contained bright purple granules. Lymphocytes displayed red nuclei and blue cytoplasm. Monocytes contained red-brown nuclei and lavender cytoplasm. Basophils showed red-orange granules. Thrombocytes stained deep purple. Compared to traditional panoptic stains like Wright's or Giemsa's, the new staining method provides brighter colors, more precise details of cellular structures, and shorter staining time. Significantly, it facilitates identification of avian leukocyte species based on differences in color as well as differences in size and shape.     

Co-expulsion of Ascaridia galli and Heterakis gallinarum by chickens

Worm expulsion is known to occur in mammalian hosts exposed to mono-species helminth infections, whilst this phenomenon is poorly described in avian hosts. Mono-species infections, however, are rather rare under natural circumstances. Therefore, we quantified the extent and duration of worm expulsion by chickens experimentally infected with both Ascaridia galli and Heterakis gallinarum, and investigated the accompanying humoral and cell-mediated host immune responses in association with population dynamics of the worms. Results demonstrated the strong co-expulsion of the two ascarid species in three phases. The expulsion patterns were characterized by non-linear alterations separated by species-specific time thresholds. Ascaridia galli burden decreased at a daily expulsion rate (e) of 4.3 worms up to a threshold of 30.5 days p.i., followed by a much lower second expulsion rate (e = 0.46), which resulted in almost, but not entirely, complete expulsion. Heterakis gallinarum was able to induce reinfection within the experimental period (9 weeks). First generation H. gallinarum worms were expelled at a daily rate of e = 0.8 worms until 36.4 days p.i., and thereafter almost no expulsion occurred. Data on both humoral and tissue-specific cellular immune responses collectively indicated that antibody production in chickens with multispecies ascarid infections is triggered by Th2 polarisation. Local Th2 immune responses and mucin-regulating genes are associated with the regulation of worm expulsion. In conclusion, the chicken host is able to eliminate the vast majority of both A. galli and H. gallinarum in three distinct phases. Worm expulsion was strongly associated with the developmental stages of the worms, where the elimination of juvenile stages was specifically targeted. A very small percentage of worms was nevertheless able to survive, reach maturity and induce reinfection if given sufficient time to complete their life cycle. Both humoral and local immune responses were associated with worm expulsion.     

Blood-meal preferences and avian malaria detection in mosquitoes (Diptera: Culicidae) captured at different land use types within a neotropical montane cloud forest matrix

Human activities modify environmental conditions, altering ecological interactions that can contribute to the increasing number of vector-borne pathogens affecting both human and wildlife populations. There is a dearth of knowledge about mosquitoes feeding preferences and their role as potential vectors of haemosporidian parasites, particularly in modified habitats. During 2013–2014 we sampled mosquitoes in five different land use types within a cloud forest matrix. From a total of 4107 adult mosquitoes, 90 were engorged. We extracted DNA from mosquito blood-meals, abdomens, and thoraxes, which belonged to seven different species. Seventeen specimens were positive for avian Plasmodium parasites. We were able to identify the blood-meal source of 10 mosquitoes, the identified vertebrate species were: Homo sapiens (Human), Sturnira hondurensis (Bat), and Bos taurus (Cow). Our results show that Culex restuans is positive for avian malaria and it is feeding on both humans and domestic animals at urban and peri-urban habitat types, where it is also an abundant species throughout the year. Furthermore, Aedes quadrivittatus, also positive for avian malaria, is feeding on humans in the well-preserved cloud forest, where this mosquito species is highly abundant. This study is the first in Mexico to provide reference data showing generalist mosquito feeding preferences and presence of avian Plasmodium at locations with different land use types.     

Somatostatin concentration and binding in the rat hypothalamus and striatum during severe insulin-induced hypoglycemia

Hypoglycemia was induced by administration of insulin (40 I.U./kg) to 24 h fasted rats. Somatostatinlike immunoreactivity (SLI) and¹²⁵I-Tyr¹¹-somatostatin binding were measured in the striatum and hypothalamus at the onset of hypoglycemic coma (5–10 min). No significant changes in SLI concentration were detected in either site although the total number of specific somatostatin receptors in the striatum membranes, but not in the hypothalamus, decreased in insulin-injected rats when compared with the control group.     

Distribution of aromatase-immunoreactive cells in the forebrain of zebra finches (Taeniopygia guttata): Implications for the neural action of steroids and nuclear definition in the avian hypothalamus

Cells immunoreactive for the enzyme aromatase were localized in the forebrain of male zebra finches with the use of an immunocytochemistry procedure. Two polyclonal antibodies, one directed against human placental aromatase and the other directed against quail recombinant aromatase, revealed a heterogeneous distribution of the enzyme in the telencephalon, diencephalon, and mesencephalon. Staining was enhanced in some birds by the administration of the nonsteroidal aromatase inhibitor, R76713 (racemic Vorozole) prior to the perfusion of the birds as previously described in Japanese quail. Large numbers of cells immunoreactive for aromatase were found in nuclei in the preoptic region and in the tuberal hypothalamus. A nucleus was identified in the preoptic region based on the high density of aromatase immunoreactive cells within its boundaries that appears to be homologous to the preoptic medial nucleus (POM) described previously in Japanese quail. In several birds alternate sections were stained for immunoreactive vasotocin, a marker of the paraventricular nucleus (PVN). This information facilitated the clear separation of the POM in zebra finches from nuclei that are adjacent to the POM in the preoptic area-hypothalamus, such as the PVN and the ventromedial nucleus of the hypothalamus. Positively staining cells were also detected widely throughout the telencephalon. Cells were discerned in the medial parts of the ventral hyperstriatum and neostriatum near the lateral ventricle and in dorsal and medial parts of the hippocampus. They were most abundant in the caudal neostriatum where they clustered in the dorsomedial neostriatum, and as a band of cells coursing along the dorsal edge of the lamina archistriatalis dorsalis. They were also present in high numbers in the ventrolateral aspect of the neostriatum and in the nucleus taeniae. None of the telencephalic vocal control nuclei had appreciable numbers of cells immunoreactive for aromatase within their boundaries, with the possible exception of a group of cells that may correspond to the medial part of the magnocellular nucleus of the neostriatum. The distribution of immunoreactive aromatase cells in the zebra finch brain is in excellent agreement with the distribution of cells expressing the mRNA for aromatase recently described in the finch telencephalon. This widespread telencephalic distribution of cells immunoreactive for aromatase has not been described in non-songbird species such as the Japanese quail, the ring dove, and the domestic fowl. © 1996 John Wiley & Sons, Inc.     

南京中山植物园秋冬季鸟类对树木果实的取食作用

在南京中山植物园中观察了19种乌类在秋冬季节对21种树木果实的取食情况。这些树木果料大多数为肉质的核果、梨果、浆果及球果等类型,在果熟时通常具有鲜艳的颜色。乌类取食果实的方式主要有：①直接在树冠上蚕食果实或在树下蚕食掉落的果实,有时在蚕食后将种子哎出;②将果实从树上衔走后,于停栖处吞食或啄食;③磨破果皮,仅以食其内的种子。鸟类取食果实虽然对园林树种的观赏性产生了一定的影响,但是乌类通过取食树木果实获得了营养,同时也促进了肉质果实中那些种皮坚硬,或者包被于坚硬果核中的种子的自然传播。     

牵拉左心房和夹闭颈总动脉对猫下丘脑前部和后部单位放电的影响

在40只氯醛糖和乌拉坦麻醉的猫,观察了牵拉左心房肺静脉入口处(atrial stretch,AS)和关闭一侧颈总动脉(carotid occlusion,CO)对下丘脑前部(AH)和下丘脑后部(PH)单位放电的影响。共记录了185个自发放电单位。对 AS 有反应的 AH 和 PH 单位分别为46.3%和23.3%,其中均以出现抑制反应者居多。有少数单位仅在 AS 开始和停止时出现短暂的兴奋反应。在上述185个神经元中观察了85个对 AS 和 CO 两种刺激的反应,有15个(17.6%)对两种刺激均反应,其中被 AS 所抑制而为 CO 所兴奋的有11个,占73.3%(11/15)。这些结果表明:(1)AS 可对 AH 神经元活动起抑制作用;(2)AS 也可影响 PH 神经元活动;(3)动脉压力感受性和心房容量感受性刺激可会聚于同一下丘脑神经元。     

H5N1亚型禽流感病毒神经氨酸酶基因的克隆与表达

根据已知H5N1亚型禽流感病毒神经氨酸酶基因(na)序列设计、合成克隆引物.自H5N1亚型病毒感染的鸡胚尿囊液中提取总RNA,反转录后采用高可信度DNA聚合酶(PyobestTMDNAPolymerase)扩增na基因,采用Invitrogen定向表达系统(ChampionTM pET directional TOPO expression system)进行克隆表达,纯化获得N末端携带多聚组氨酸标签的重组神经氨酸酶,分子量约53.8kDa.分析重组NA的免疫反应性和免疫原性,结果表明重组NA能与H5N1亚型病毒抗血清发生特异性结合,且其免异动物后能诱导机体产生特异性抗体,具有良好的抗原性.