Interannual variability of seasonal succession events in a temperate lake and its relation to temperature variability

The assessment of possible implications of anthropogenic climate change requires the evaluation of results obtained with complex climate models. Here we considered the problem of assessing the impact of climate variability on successional events in a lake (Plußsee) of the temperate region between January and May. We first established a statistical link between large-scale air temperature, at about 1500 m height, and the local temperature, in order to bridge the spatial gap of information obtained from global climate models and local climate which forces processes in the lake. Secondly, the local temperatures were statistically related to biologically induced dynamic features in the lake, derived from Secchi depths readings (as integrated measures). The observed relationships were compared with results from a phyto- and zooplankton population-dynamic model run under different temperature regimes. The local temperatures approximated closely the large-scale temperature. The timing of phyto- and zooplankton maxima (clearwater phase) were negatively related to the temperature. Thus, with a temperature increase both occurred earlier. The intensity of the spring algal maximum was negatively related to its timing, whereas no clear relation between the timing and intensity of the clearwater phase (zooplankton maximum) could be obtained.     

Histochemical distribution of sudanophilic and unsaturated lipids in the testes of buffalo, goat, and ram

The sudanophilic and unsaturated lipids have been histochemically localized and correlated with seminiferous epithelial cycle in the testes of buffalo (Bubalus bubalis), goat (Capra hircus) and ram (Ovis aries). All sudanophilic lipids are unsaturated. The masked lipids may be present either in small quantity or absent altogether. In the seminiferous tubules, 3 types of lipid bodies (L1, L2, L3) are present. L3 bodies in the buffalo are of relatively small size but are more in number. L2 bodies appear only in the elongated spermatids. All spermatogenic cells also have diffused sudanophilic lipids. Sertoli cells contain only L1 and L3. The lipids in the spermatids and Sertoli cells show cyclic variations reverse to each other. In the interstitial tissue, the amount of lipids is much less in goat and ram as compared to that in buffalo.     

Histochemical nature of cortical granules in the human egg

Summary The distribution and histochemical nature of cortical granules have been studied in the human egg. They are distributed as small granules adjacent to the plasma membrane of growing oocytes, and consist of carbohydrates and possibly some protein. The cortical granules of the human egg have been compared and contrasted to those in Amphioxus, fishes, and amphibians.     

GC-1 mRHBDD1 knockdown spermatogonia cells lose their spermatogenic capacity in mouse seminiferous tubules

Background  

Apoptosis is important for regulating spermatogenesis. The protein mRHBDD1 (mouse homolog of human RHBDD1)/rRHBDD1 (rat homolog of human RHBDD1) is highly expressed in the testis and is involved in apoptosis of spermatogonia. GC-1, a spermatogonia cell line, has the capacity to differentiate into spermatids within the seminiferous tubules. We constructed mRHBDD1 knockdown GC-1 cells and evaluated their capacity to differentiate into spermatids in mouse seminiferous tubules.     

Cloning and expression analysis of two distinct HIF-alpha isoforms – gcHIF-1alpha and gcHIF-4alpha – from the hypoxia-tolerant grass carp,Ctenopharyngodon idellus

Background  

Hypoxia-inducible factors (HIFs) are involved in adaptive and survival responses to hypoxic stress in mammals. In fish, very little is known about the functions of HIFs.     

Morphological and histochemical studies on the prostate gland of developing and adult Paramphistomum cervi (Digenea: Paramphistomatidae)

Morphological and histochemical studies have been made on the development of the prostate gland of the digenetic trematode, Paramphistomum cervi during the course of its infection in sheep; histochemical characterization of prostate gland secretion in adult worms and its functional relationship with the transport of spermatozoa have also been studied. In 6-wk-old worms, the terminal portion of the male genital duct is formed of what appears to be a syncytial epithelium containing a relatively large number of nuclei compared to the rest of the male duct. Cellular organization of the prostate gland becomes conspicuous in 8-wk-old worms and the prostate gland is fully developed by 16 wk. Two types of prostate gland cells, characteristic of the adult, become distinct in 16-wk-old worms which contain spermatozoa in the lumen of their vas deferens and pars prostatica. Adult worms show two types of prostate gland cells: type I containing mainly glycoprotein and type II mainly phospholipid granules. Weak-to-strong activities of acid phosphatase, alkaline phosphatase, esterase, lipase, adenosine triphosphatase, tetrazolium reductase, NAD-diaphorase, isocitrate dehydrogenase, glyceraldehyde dehydrogenase, α-glycerophosphate dehydrogenase and glucose-6-phosphate dehydrogenase have been observed in the prostate gland. The release of prostate gland secretion and the passage of spermatozoa through the lumen of pars prostatica appear to be synchronized events.     

Histochemical observations on lipid changes during oogenesis in the poultry nematode,Ascaridia galli

During oogenesis lipids continue to increase in Ascaridia galli leading to the formation of massive accumulations in larger oocytes. In addition to neutral lipids (triacylglycerols), small amounts of cholesterol and granules containing phospholipids and lipoproteins are seen in the ooplasm of growing and mature oocytes. Lipid inclusions of oogonia which are in the form of coarse granules show a complex structure in young oocytes and form droplets and globules in growing and mature oocytes. Changes in the morphology of the oocytes are accompanied by changes in the distribution of lipids within the oocytes. Localization of lipids in rachis and ovarian epithelium along the length of the ovary is also described.