Vertical profiles of environmental factors within tropical rainforest, Lambir Hills National Park, Sarawak, Malaysia

Environmental factors, such as global solar radiation, wind speed, air temperature, humidity, and CO₂ concentration, were measured above and within the canopy of a tropical rainforest in Lambir Hills National Park, Sarawak, Malaysia. Few data concerning the environment of this forest have been reported. Intensive observations were carried out in 1998, 1999, and 2000 with the following results: (1) The fraction of global solar radiation reaching the upper layer of the canopy varied with global solar radiation above the canopy. Even though the global solar radiation above the canopy fluctuated, the fraction of that reaching the lower canopy and the ground was constantly approximately 5%. (2) The fraction of wind speed reaching each layer of the canopy increased with wind speed above the canopy. Little wind was usually present at the lower canopy. (3) The daytime air temperature at the canopy top was higher than that near the ground. The maximum difference between the air temperature at the canopy top and that at the ground was about 5°C, and the diurnal temperature ranges at the canopy top and those at the ground were about 8°C and about 5°C, respectively. The highest daytime water vapor pressure occurred within the canopy and particularly near the ground. Vertical gradients of water vapor pressure during the day were steep, probably because of high transpiration. (4) In the 1998 observation the minimum and the maximum CO₂ concentrations were 360 ppm in the day and 450 ppm at night, while in the 2000 observation the minimum and the maximum CO₂ concentrations were 350 ppm in the day and 540 ppm at night. The higher CO₂ concentration in the daytime and the lower concentration at night observed during the 1998 observation period were probably due to reduced photosynthesis and soil respiration caused by exceptional dry conditions during the observation period.     

Simplified culture method of detached ears and its application to vernalization in wheat

Summary The effects of the addition of sulfurous acid into culture solution and of cold treatment of the solution were examined to simplify the culture of detached wheat ears. In the simplified method, detached ears could be cultured at room temperature on the liquid medium containing 100 g/l sucrose and 0.075% sulfurous acid without any sterilization. The immature seeds in detached ears cultured by this method were treated with low temperature or with chemicals known to have vernalizing effect. The chemical treatment did not affect the chilling requirement of immature embryos, although photoperiodic response and narrow-sense earliness were reduced by kinetin and trypsin. The low temperature treatment drastically affected the chilling requirement, and fully vernalized mature seeds having normal germinability were obtained by treating the detached ears in culture with low temperature from 10 days after anthesis.     

Disseminated tuberculosis in hyrax (Procavia capensis) caused by Mycobacterium africanum

Tuberculosis due to Mycobacterium africanum was diagnosed in an adult female hyrax (Procavia capensis). Pathologic examination revealed disseminated tuberculous lesions. The same pathologic changes were also found in a male hyrax that died a year later. Both animals were imported from the United Arab Emirates and were held in captivity at the Zagreb Zoo in Croatia. The source of infection remains unknown. The acid-fast bacteria isolated from the lungs of the female hyrax were identifyed by polymerase chain reaction as Mycobacterium tuberculosis complex and Geno Type MTBC test confirmed the strain to be M. africanum I.     

Microvascular architecture of the rabbit eye: a scanning electron microscopic study of vascular corrosion casts

The microvasculature of the eyes of 5 rabbits was investigated using scanning electron microscopy on corrosion casts. The study revealed that the pars plana vessels draining blood from the iris and ciliary body coursed directly into the anterior vortex venous system constituting the scleral venous plexus (the venous circle of Hovius). The episcleral vasculature was found to possess a specialized morphology, with channels draining the aqueous humor. The capillaries of the third palpebral, bulbar and palpebral conjunctiva formed a single-layered capillary network approximately parallel to the epithelium and formed a well-developed venous plexus in the stroma. The retina was found to be merangiotic, meaning that vessels were present only in a small part of the retina, extending in a horizontal direction to form bands on either side of the optic disc. Channels representing the aqueous veins that drained blood mixed with aqueous humor were found to derive directly from the suprachoroidal space and communicate with the scleral venous plexus via the anterior vortex veins. The functional significance of the microvasculature of the iris, cilia, retina and choroid is discussed in this report as well. The elaborate microvasculature of the conjunctiva may be a prerequisite for the exchange of nutrients and gasses between the cornea and the vessels across the conjunctival epithelium when the eyelids are shut during sleep, and possibly for the dynamics of eye drop delivery. The scleral venous plexus in rabbits may be analogous to the scleral venous sinus (Schlemm's canal) in rats, primates and humans.     

Microvascular anatomy of the pig eye: scanning electron microscopy of vascular corrosion casts

The microvasculature of the eye of 10 pigs was investigated using scanning electron micrographs of corrosion casts. The ciliary body, iris and bulbar conjunctiva were supplied by the iridociliary ring artery via the long posterior ciliary artery. Capillaries of the ciliary process were of large diameter (23.2-27.5 microm) with an irregular bore, forming a thoroughfare channel draining blood in the ciliary arterioles into the pars plana venous vessels. Arterioles and venules in the iris exhibited a zigzag or spiral features. The third palpebra was supplied by the anterior ciliary artery. The capillary bed of the third palpebra was dense and was formed by many rows of fine hair-pin loops. Capillaries in the bulbar conjunctiva formed a sparse network disposing approximately parallel to the epithelium and formed a well-developed venous plexus, draining into the vortex veins. Retinal arterioles formed a slender and long course to capillaries. Retinal capillaries were extremely thin (3.0-4.0 microm in diameter). The choroid was supplied by the short posterior ciliary arteries. Choroidal arterioles exhibited a thick and short course to the choriocapillaris. The choriocapillaris was flat and sinusoid-like (8.9-13.9 microm in diameter), forming a dense sheet-like network. Blood from the choroid emptied into the episcleral vein via the vortex vein. Blood from the retina was drained by the posterior ciliary veins. The functional significance of this vascular architecture was discussed.     

Plum pox virus as a stress factor in the vegetative growth, fruit growth and yield of plum (Prunus domestica) cv. ‘Cacanska Rodna’

During 2005–2007, under the environmental conditions of Cacak (43°53’N; 20°21’E), western Serbia, the effect of Plum pox virus (PPV) on the phenology of vegetative shoot and fruit growth was investigated in a plum orchard of cv. ‘Cacanska Rodna’ including trees non-infected with PPV and those with infection and clearly visible symptoms, as verified by RT-PCR. The results showed that PPV did not affect the growth phenology of the vegetative shoot (length and thickness) and the fruit growth. However, it caused negative effects on the average length (22.31 ± 0.28 cm in non-infected trees, 18.35 ± 0.07 cm in infected trees) and thickness (4.21 ± 0.03 mm in non-infected trees, 4.01 ± 0.02 mm in infected trees) of vegetative shoots as well as on the average fruit weight (20.43 ± 0.16 g in non-infected fruits, 17.58 ± 0.18 g in infected fruits) and fruit dimensions. The greatest effect of PPV during the trial was the induction of a massive premature fruit drop and, consequently, a 52.94% decrease in total yields per tree (18.0 ± 1.10 kg) and unit area (12.0 ± 0.89 t ha^-1) in infected vs non-infected trees.     

Azimuthal variations of sap flux density within Japanese cypress xylem trunks and their effects on tree transpiration estimates

Sap flow techniques are practical tools for estimating tree transpiration. Though many previous studies using sap flow techniques did not consider azimuthal variations of sap flux density (F _d) on xylem trunk to estimate tree transpiration, a few studies reported that ignoring the azimuthal variations in F _d could cause large errors in tree transpiration estimates for some tree species. Therefore, examining azimuthal variations in F _d for major plantation tree species is critical for estimating tree transpiration. Using the thermal dissipation method, we examined azimuthal variations in F _d in six trees of Japanese cypress Chamaecyparis obtusa (Sieb. et Zucc.) Endl., which is one of the most common plantation tree species in Japan. We recorded considerable variations among F _d at four different azimuthal directions. The F _d value for one aspect was more than 100% larger than those for the other aspects. We calculated differences between tree transpiration estimates based on F _d for one to three azimuthal directions and those based on F _d for four aspects. The differences relative to tree transpiration estimates based on F _d for four aspects were typically 30, 20, and 10% in accordance with the F _d for one, two, and three measurement aspects, respectively. This finding indicates that ignoring azimuthal variations could cause large errors in tree transpiration estimates for Japanese cypress.     

N -ethyl- N -nitrosourea induces retinal photoreceptor damage in adult rats

Seven-week-old male Lewis rats received a single intraperitoneal injection of N-ethyl-N-nitrosourea (ENU) (100, 200, 400 or 600 mg/kg), and retinal damage was evaluated 7 days after the treatment. Sequential morphological features of the retina and retinal DNA damage, as determined by a TUNEL assay and phospho-histone H2A.X (γ-H2AX), were analyzed 3, 6, 12, 24 and 72 hr, 7 days, and/or 30 days after 400 mg/kg ENU treatment. Activation of the nuclear enzyme poly (ADP-ribose) polymerase (PARP) was analyzed immunohistochemically by poly (ADP-ribose) (PAR) expression in response to DNA damage of the retina. All rats that received ≥ 400 mg/kg of ENU developed retinal degeneration characterized by the loss of photoreceptor cells in both the central and peripheral retina within 7 days. In the 400 mg/kg ENU-treated rats, TUNEL-positive signals were only located in the photoreceptor cells and peaked 24 hr after ENU treatment. The γ-H2AX signals in inner retinal cells appeared at 24 hr and peaked at 72 hr after ENU treatment, and the PAR signals selectively located in the photoreceptor cell nuclei appeared at 12 hr and peaked at 24 hr after ENU treatment. However, degeneration was restricted to photoreceptor cells, and no degenerative changes in inner retinal cells were seen at any time points. Retinal thickness and the photoreceptor cell ratio in the central and peripheral retina were significantly decreased, and the retinal damage ratio was significantly increased 7 days after ENU treatment. In conclusion, ENU induced retinal degeneration in adult rats that was characterized by photoreceptor cell apoptosis through PARP activity.     

Yersiniosis in zoo marmosets (Callitrix jacchuss) caused by Yersinia enterocolitica 4/O:3

The aim of this research was to describe two fatal cases of Yersinia enterocolitica bioserotype 4/O:3 infection in non-human primates and to characterise the isolates by PCR and PFGE. In July 2004, two marmosets (Callitrix jacchuss) born in captivity in Zagreb Zoo, died following a few days of intermittent diarrhoea in intervals of 2 weeks. The pathomorphological diagnosis of the female (born in 1997) and the male (born in 1995) marmoset, was disseminated miliary necrosis of the liver. Y. enterocolitica 4/O:3 was isolated from both livers showing that monkeys are susceptible to this bioserotype. The ail gene, which is an essential chromosomal virulence factor in pathogenic Y. enterocolitica isolates, was present in the marmoset isolates. Two different PFGE patterns were obtained from the isolates of the male liver with NotI enzyme. One genotype of the male marmoset isolate was indistinguishable from the genotype of the female marmoset isolate when NotI, ApaI and XhoI enzymes were used indicating a common infection source for the marmosets. The genotypes of the marmoset isolates differed only slightly from one human (of seven Croatian isolates) and from one pig isolate (representing a common genotype found among human and porcine isolates in Germany) suggesting that raw pork fed to the marmoset could have been the infection source.     

A Case Report of a Malignant Fibrous Histiocytoma in a T-cell Receptor β Chain and p53 Double-knockout Mouse

A subcutaneous tumor was found in the right abdomen of a 16-week-old male TCRβ and p53 double-knockout mouse. The tumor had indistinct borders with the surrounding tissue. The cut surface after formalin fixation was pale yellowish white, partially dark red and partly white. Histologically, the tumor was composed of three distinct regions. The first region showed pleomorphic cells arranged in sheets. The second region showed spindle cells arranged in interlacing fascicles. The final region contained a mixture of the above mentioned two types of cells. Furthermore, a small amount of collagen fibers, round cells, multinucleated giant cells, and cells with eosinophilic granules were observed between these tumor cells. Immunohistochemical examination and electron microscopy identified that the pleomorphic cells and spindle cells were histiocytes and fibroblasts, respectively, and that the round cells were undifferentiated mesenchymal cells. Based on these findings, the tumor was diagnosed as a malignant fibrous histiocytoma.