Genomic and neural analysis of the estradiol-synthetic pathway in the zebra finch

<p>Abstract</p> <p>Background</p> <p>Steroids are small molecule hormones derived from cholesterol. Steroids affect many tissues, including the brain. In the zebra finch, estrogenic steroids are particularly interesting because they masculinize the neural circuit that controls singing and their synthesis in the brain is modulated by experience. Here, we analyzed the zebra finch genome assembly to assess the content, conservation, and organization of genes that code for components of the estrogen-synthetic pathway and steroid nuclear receptors. Based on these analyses, we also investigated neural expression of a cholesterol transport protein gene in the context of song neurobiology.</p> <p>Results</p> <p>We present sequence-based analysis of twenty steroid-related genes using the genome assembly and other resources. Generally, zebra finch genes showed high homology to genes in other species. The diversity of steroidogenic enzymes and receptors may be lower in songbirds than in mammals; we were unable to identify all known mammalian isoforms of the 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase families in the zebra finch genome assembly, and not all splice sites described in mammals were identified in the corresponding zebra finch genes. We did identify two factors, Nobox and NR1H2-RXR, that may be important for coordinated transcription of multiple steroid-related genes. We found very little qualitative overlap in predicted transcription factor binding sites in the genes for two cholesterol transport proteins, the 18 kDa cholesterol transport protein (TSPO) and steroidogenic acute regulatory protein (StAR). We therefore performed in situ hybridization for TSPO and found that its mRNA was not always detected in brain regions where StAR and steroidogenic enzymes were previously shown to be expressed. Also, transcription of TSPO, but not StAR, may be regulated by the experience of hearing song.</p> <p>Conclusions</p> <p>The genes required for estradiol synthesis and action are represented in the zebra finch genome assembly, though the complement of steroidogenic genes may be smaller in birds than in mammals. Coordinated transcription of multiple steroidogenic genes is possible, but results were inconsistent with the hypothesis that StAR and TSPO mRNAs are co-regulated. Integration of genomic and neuroanatomical analyses will continue to provide insights into the evolution and function of steroidogenesis in the songbird brain.</p

Expression of αvβ6integrin in oral leukoplakia

The distribution of αvβ6integrin was examined in oral leukoplakia, lichen planus and squamous cell carcinomas using immunohistochemistry. Controls included oral mucosal wounds, chronically inflamed and normal oral mucosa. Integrins β1, β3, β4, β5, fibronectin and tenascin were also studied. The integrin αvβ6was highly expressed throughout the whole lesion of 90% of the squamous cell carcinomas but was not present in any of the normal specimens. αvβ6integrin was also expressed in 41% of the leukoplakia specimens, and 85% of the lichen planus samples, but in none of the tissues with inflammatory hyperplasia or chronic inflammation. The expression of β1 integrins was localized in the basal layer, and that of the β4at the cell surface facing the basement membrane of all specimens. The integrins β3and β5were absent from all normal and leukoplakia specimens. Fibronectin and tenascin were present in the connective tissue underneath the epithelium of all the sections, and their expression was similar in both αvβ6-positive and αvβ6-negative tissues. A group of 28 leukoplakia patients were followed 1–4 years after first diagnosis. In this group, initially αvβ6integrin-positive leukoplakia specimens had high tendency for disease progression while αvβ6-negative specimens did not progress. These results suggest that the expression of αvβ6integrin could be associated in the malignant transformation of oral leukoplakias. © 2000 Cancer Research Campaig

The Type VI secretion system deploys anti-fungal effectors against microbial competitors

This work was supported by the Wellcome Trust (Senior Research Fellowship in Basic Biomedical Science to S.J.C., 104556; 097377, J.Q.; 101873 & 200208, N.A.R.G.), the MRC (MR/K000111X/1, S.J .C; MC_UU_12016/5, M.T.), and the BBSRC (BB/K016393/1 & BB/P020119/1, J.Q.). We thank Maximilian Fritsch, Mario López Martín and Birte Hollmann for help with strain construction; Gary Eitzen for construction of pGED1; Donna MacCallum for the gift of Candida glabrata ATCC2001; Joachim Morschhäuser for the gift of pNIM1; Gillian Milne (Microscopy and Histology facility, University of Aberdeen) for assistance with TEM; and Peter Taylor, Michael Porter, Laura Monlezun and Colin Rickman for advice and technical assistance.Peer reviewedPostprin

Comparative morpho-functional study of the intestine of the Antarctic fish Notothenia coriiceps and Trematomus newnesi (Nototheniidae): Histology and ultrastructure

Seasonal variation in the photoperiod and light intensity in the Antarctic region influences the biomass and primary productivity in the Antarctic Ocean. This results in specialized adaptations for obtaining food, associated with morphological and physiological changes in the digestive tract of fish. The aim of the present study is the morpho-functional study of the intestine of two Antarctic Nototheniidae : Notothenia coriiceps, a benthic fish that shows relatively low levels of activity, and Trematomus newnesi, a semi-pelagic fish. Both show a proportionally big stomach and a short intestine. Those are the main characteristics of carnivorous fish. The intestinal mucosa is lined by a simple columnar epithelium with enterocytes, goblet cells, lymphocytes and rodlet cells. Goblet cells produce neutral and acid mucosubstances along the whole of the intestine, in both species. Enterocytes at the pyloric ceca and the proximal portion of the medium intestine in N. coriiceps, as well as the medium intestine of T. newnesi, show ultrastructural characteristics of lipid absorption cells. Enterocytes with characteristics of protein absorbing cells were observed along the posterior intestine of both species. In addition, N. coriiceps shows deep folds at the posterior intestine and a high concentration of blood capillaries, suggesting that in this region there is active transport of macromolecules by pinocytosis. Osmoregulation seems to occur mainly in the medial and distal portions of the medium intestine in N. coriiceps, while in T. newnesi it occurs along the entire medium intestine. These differences in intestinal functional morphology in both species can be related to their feeding habits and their energetic metabolism, resulting from different utilization of food nutrients, as N. coriiceps is a generalist, while T. newnesi ingests a narrow spectrum of food items

ナンキョクサン ギョルイ Notothenia coriiceps, Trematomusnewnesi (ノトセニアカ) チョウ ノ ヒカク ケイタイ キノウガク テキ ケンキュウ ソシキガク ト ビサイ コウゾウ

南極地域の日照時間と日射強度の季節変化は, 南極海の生物現存量と基礎生産力に影響を与えている。その結果として, 魚類の消化管に, 形態学的, 生理学的変化を伴うような食物摂取上独特な適応が生ずる。本研究の目的は, 2種類の南極産ノトセニア科魚類, 底生性で活動度の比較的低いNotothenia coriiceps, ならびに半漂泳性の魚であるTrematomus newnesiの腸の形態-機能学的研究を行うことである。両種とも, 食肉性魚類の主な特徴である, 割合に大きな胃と短い腸を持っている。腸粘膜は吸収上皮細胞, 杯細胞, リンパ球, 小桿細胞を含む単層円柱上皮から成っている。中性, 酸性の粘液物質を生産する杯細胞は, 両種とも腸全域に亘って分布する。N. coriicepsの幽門垂, 中腸前部, そしてT. newnesiの中腸にある吸収上皮細胞は脂質吸収細胞としての微細構造上の特徴を示す。蛋白質吸収細胞としての特徴を持つ吸収上皮細胞は, 両種ともに, 腸の後部に認められる。加えてN. coriicepsの腸後部には深いひだがあり, そこには毛細血管が集中し, 飲作用により大型分子の活溌な輸送が行われているものと思われる。滲透圧調節は, N. coriicepsの場合主として中腸の中, 後部でなされ, T. newnesiでは中腸の全域でなされる。腸の機能的形態における, 両種のこれらの差異はN. coriicepsが広食性であるのに対し, T. newnesiの食物の選択幅が狭いという, 2種の食性の差異とエネルギー代謝の差異とに依るものと思われる。Seasonal variation in the photoperiod and light intensity in the Antarctic region influences the biomass and primary productivity in the Antarctic Ocean. This results in specialized adaptations for obtaining food, associated with morphological and physiological changes in the digestive tract of fish. The aim of the present study is the morpho-functional study of the intestine of two Antarctic Nototheniidae : Notothenia coriiceps, a benthic fish that shows relatively low levels of activity, and Trematomus newnesi, a semi-pelagic fish. Both show a proportionally big stomach and a short intestine. Those are the main characteristics of carnivorous fish. The intestinal mucosa is lined by a simple columnar epithelium with enterocytes, goblet cells, lymphocytes and rodlet cells. Goblet cells produce neutral and acid mucosubstances along the whole of the intestine, in both species. Enterocytes at the pyloric ceca and the proximal portion of the medium intestine in N. coriiceps, as well as the medium intestine of T. newnesi, show ultrastructural characteristics of lipid absorption cells. Enterocytes with characteristics of protein absorbing cells were observed along the posterior intestine of both species. In addition, N. coriiceps shows deep folds at the posterior intestine and a high concentration of blood capillaries, suggesting that in this region there is active transport of macromolecules by pinocytosis. Osmoregulation seems to occur mainly in the medial and distal portions of the medium intestine in N. coriiceps, while in T. newnesi it occurs along the entire medium intestine. These differences in intestinal functional morphology in both species can be related to their feeding habits and their energetic metabolism, resulting from different utilization of food nutrients, as N. coriiceps is a generalist, while T. newnesi ingests a narrow spectrum of food items

PROTEIN-SYNTHESIS in ISOLATED SYMBIONTS FROM the FLAGELLATE PROTOZOAN CRITHIDIA-DEANEI

ESCOLA PAULISTA MED,DEPT MICROBIOL IMMUNOL & PARASITOL,RUA BOTUCATU 862,BR-04023 São Paulo,SP,BRAZILESCOLA PAULISTA MED,DEPT MICROBIOL IMMUNOL & PARASITOL,RUA BOTUCATU 862,BR-04023 São Paulo,SP,BRAZILWeb of Scienc