Intercellular bridges between germ cells in the immature golden hamster testis: evidence for clonal and non-clonal mode of proliferation

Summary Intercellular bridges of prespermatogonia and of the first A-spermatogonia in the maturing testes of newborn to 17-day-old golden hamsters have been studied by electron microscopy. Incomplete cytokinesis of dividing M- and T₂-prespermatogonia and A-spermatogonia produces these bridges, which undergo different developmental fates. Bridges of the first A-spermatogonia are stable beyond subsequent mitoses of these cells; this gradually leads to the formation of bridge-connected groups of synchronously developing germ cells. Thus, the clonal mode of male germ cell proliferation is already established in this period of testis maturation. During mitoses, pre-existing bridges reversibly develop structural modifications, i.e. considerable elongation and formation of a bridge-partitioning complex. In contrast, intercellular bridges of prespermatogonia are mostly severed and become lost during subsequent mitoses of the cells involved; this results in separation of the germ cells and represents a mainly non-clonal mode of M- and T₂-prespermatogonial proliferation. Here, too, pre-existing bridges elongate and develop the bridge-partitioning complex during subsequent mitoses of the joined cells, but this is superposed and interrupted by the simultaneous process of disconnection of the bridges.Parts of this study were presented at the 85th meeting of the Anatomische Gesellschaft in Munich, April 1990     

Über zusätzliches Reizleitungsgewebe im Goldhamsterherzen

Zusammenfassung Histologisch, enzymhistochemisch und mit Hilfe formaldehyd-induzierter Fluoreszenz wird im rechten Vorhof des Goldhamsterherzens Reizleitungsgewebe nachgewiesen, das weder zum Sinus- noch zum AV-Knoten gehört. Dieses Gewebe gleicht in Struktur, Stoffwechsel, Vaskularisation und Innervation der übrigen Reizleitungsmuskulatur. Die funktionelle Bedeutung des zusätzlichen Knotengewebes wird diskutiert.

---

Additional conductive tissue in the golden hamster heart

Summary In the right atrium of the heart of the golden hamster histology, enzyme histochemistry, and formaldehyde-induced fluorescence reveal conductive tissue, which does not belong to the SA or AV node. Morphology, metabolism, vascularisation, and innervation of this tissue are the same as in the other regions of the impulse conducting system. The functional significance of the additional nodal tissue is discussed.

     

Abstracts of papers and posters presented at the 33rd conference of the New Zealand society for Parasitology,at Massey University,Palmerston North, 24 October 2006

Abstract

Eight species of Recent Braohiopoda dredged from the fiords of south-western New Zealand in 1946 included first records for Fiordlarrd of Crania, Amphithyris, and Liothyrella. Amphithyris richardsonae n.sp. is described from a live-collected individual from 74 m, Long Sound, Preservation Inlet; it differs from A. buckmani Thomson and A. hallettensis Foster in shape, attachment, and details of ornament. Ventml valves fTom 101 m, Dagg Sound, characterised by coarse punctation and an ornament of hollow spines are treated as Platidiidae genus and species indeterminate.     

Nutritional enhancement of rice for human health: The contribution of biotechnology

Micronutrient malnutrition is widespread, especially in poor populations across the globe where daily caloric intake is confined mainly to staple cereals. Rice, which is a staple food for over half of the world's population, is low in bioavailable micronutrients required for the daily diet. Improvements of the plant-based diets are therefore critical and of high economic value in order to achieve a healthy nutrition of a large segment of the human population. Rice grain biofortification has emerged as a strategic priority for alleviation of micronutrient malnutrition. Nutritional enhancement of crops through conventional breeding is often limited by the low genetic variability for required dietary micronutrient levels. In this case, biotechnology strategies offer effective and efficient perspectives. In this review, we discuss genetic engineering approaches that have been successful in the nutritional enhancement of rice endosperm. These advancements will make substantial contributions to crop improvement and human nutrition. Their practical application, however, also demands visionary changes in regulatory policies and a broader consumer acceptance.     

金双歧联合四君子合剂治疗婴幼儿厌食症疗效观察

目的 观察金双歧联合四君子合剂治疗小儿厌食症临床疗效.方法 将108例患儿按简单随机抽样法分为治疗组56例和对照组52例,两组均予口服金双歧治疗,治疗组联合四君子合剂治疗,观察两组患儿服药后食欲改善情况.连续治疗6周后,对两组疗效进行对比.结果 治疗组总有效率为92.1％;对照组总有效率为59.6％,两组比较差异有统计学意义(P＜0.05).结论 金双歧联合四君子合剂治疗小儿厌食症疗效显著,且安全无不良反应,值得临床推广应用.     

A Universal Method for the Identification of Bacteria Based on General PCR Primers

The Universal Method (UM) described here will allow the detection of any bacterial rDNA leading to the identification of that bacterium. The method should allow prompt and accurate identification of bacteria. The principle of the method is simple; when a pure PCR product of the 16S gene is obtained, sequenced, and aligned against bacterial DNA data base, then the bacterium can be identified. Confirmation of identity may follow. In this work, several general 16S primers were designed, mixed and applied successfully against 101 different bacterial isolates. One mixture, the Golden mixture7 (G7) detected all tested isolates (67/67). Other golden mixtures; G11, G10, G12, and G5 were useful as well. The overall sensitivity of the UM was 100% since all 101 isolates were detected yielding intended PCR amplicons. A selected PCR band from each of 40 isolates was sequenced and the bacterium identified to species or genus level using BLAST. The results of the UM were consistent with bacterial identities as validated with other identification methods; cultural, API 20E, API 20NE, or genera and species specific PCR primers. Bacteria identified in the study, covered 34 species distributed among 24 genera. The UM should allow the identification of species, genus, novel species or genera, variations within species, and detection of bacterial DNA in otherwise sterile samples such as blood, cerebrospinal fluid, manufactured products, medical supplies, cosmetics, and other samples. Applicability of the method to identifying members of bacterial communities is discussed. The approach itself can be applied to other taxa such as protists and nematodes.     

金双歧联合茵桅黄口服液治疗母乳性黄疸疗效观察

目的探讨治疗新生儿母乳性黄疸的有效方法。方法将185例新生儿母乳性黄疸分为治疗组和对照组,治疗组的新生儿在出生后24 h内开始口服金双歧(0.5 g/次,3次/d,温水冲服),同时口服茵桅黄口服液(5 mL/次,2次/d),疗程5～7 d。对照组不采取任何干预措施。结果治疗组胆红素日均下降值为(42.31±16.12)μmol/L显著高于对照组的(22.26±11.25)μmol/L(P<0.05);观察组胆红素下降至119.5μmol/L以下的天数为(4.2±1.9)d,显著短于对照组的(7.8±3.5)d(P<0.05)。结论金双歧联合茵桅黄口服液应用于母乳性黄疸,可迅速降低胆红素水平,缩短治疗时间,无副作用,值得临床推广应用。     

血雉卵的人工孵化

2008～2010年,北京动物园在陕西洋县长青自然保护区采集血雉卵进行人工孵化研究。卵的保存及运输期为5～7d,卵保存温度17.14～18.66℃,湿度73.5%～87.1%,卵使用防震运输箱经34h运输后入孵,运输过程温度在16.38～25.95℃之间。孵化前使用碘氟稀释液擦拭卵表面。35枚受精卵中,19枚使用3台孵化机孵化,孵化温度37.4～37.5℃,使用14%～33%、40%～45%和60%～70%3个湿度梯度孵化;16枚卵使用乌鸡代亲孵化,袖珍温度记录仪测量乌鸡孵化温度在34.81～39.18℃之间,孵化环境湿度为23.4%～72.4%。记录孵化过程中的卵重量变化和孵化期。结果表明:研究期间血雉卵平均孵化率为76.5%,其中机器孵化率为84.2%,代亲孵化率为68.8%;平均孵化期为27d11h;卵失重率11.23%～16.54%,平均为13.77%±1.51%。     

Snow and land use alter pheasant survival in South Dakota

We examined survival of ring-necked pheasants (Phasianus colchicus) occupying fragmented landscapes within the Prairie Pothole Region in South Dakota, USA, where severe winter weather events historically limited pheasant population growth through increased mortality. Recent landscape transformations could further affect overwinter adult female survival by reducing critical winter resources. Assessing the influence of time-dependent landscape features on survival at small focal scales may reveal spatially important relationships. We captured and monitored 321 adult female pheasants from 2017–2019 and recorded 110 pheasant winter mortalities. Female pheasant winter survival was 0.66 (85% CI = 0.62–0.70) and was inversely correlated to snow depth. We generated Cox proportional hazard models to determine risk of mortality associated with landscape features. Pheasants using landscapes other than perennial cover (i.e., emergent wetland, tall vegetation, woody, food plots) experienced a 2.22 times greater risk of raptor predation than pheasants using perennial cover. Additionally, pheasants experienced a 58% reduced risk of weather mortality when using emergent wetlands. We analyzed resource selection ratios to understand how perceived landscape risks at the population level scaled down to land use selection at the individual level. Female pheasants selected for emergent wetlands, showed no selection for woody features, and avoided tall vegetation (non-aquatic herbaceous vegetation >75 cm) during severe winters. Pheasants would greatly benefit from conservation of emergent wetlands and integrating perennial cover into harvested cropland.     

金黄地鼠封闭群SPF化后的微卫星遗传学检测

目的检测和评估金黄地鼠封闭群SPF化后的遗传学变化,为SPF金黄地鼠遗传质量的控制提供技术资料。方法应用小鼠和大鼠的微卫星标记筛选适于金黄地鼠遗传检测的微卫星标记,并结合微卫星荧光标记-半自动基因分型技术,对成都生物制品研究所的SPF级金黄地鼠及其来源的普通级金黄地鼠进行遗传检测,计算其群体遗传学参数。结果对18个小鼠和6个大鼠微卫星标记进行了筛选,分别有2个小鼠和2个大鼠微卫星标记在金黄地鼠种群中具PCR扩增多态性。4个检测的微卫星位点在普通级金黄地鼠和SPF金黄地鼠种群分别发现25和20个等位基因,两群体的期望杂合度分别为0.4979和0.5048,其群体遗传多样性无显著差异;群体间的不同微卫星位点FST范围从0.0095到0.0367,平均为0.0315,表明两群体间的遗传分化很弱,其遗传多样性主要存在于群体内;Nei(1972)遗传距离和Nei(1978)无偏遗传距离分别为0.0678和0.0570,表明了2群体之间很高的遗传相似度和非常近的亲缘关系;Hardy-Weinberg平衡检验表明普通级和SPF金黄地鼠分别有2个和3个位点偏离遗传平衡,且偏离位点均表现为杂合子缺陷。结论该SPF金黄地鼠基本保持了其来源普通级黄地鼠的遗传多样性,两群体间遗传分化程度和遗传差异很小,但应进一步加强其封闭群的繁育控制,保持其遗传稳定性。