Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. I. Vegetative Growth

In this study the vegetative growth parameters of normally developed and underdeveloped shoots were compared in an attempt to quantify shoot heterogeneity in a Shiraz/Richter 99 vineyard. A field trial was performed in the Stellenbosch area,Western Cape, South Africa. Comparisons based on certain vegetative growth parameters were made between normally developed and underdeveloped shoots from both shaded and well-exposed canopies. The longer primary shoots of the normally developed shoots matured earlier in the season, with less apparent competition between shoot lignification and grape ripening. Reserves were more evenly distributed in these shoots. Total starch content over the whole shoot was found to be higher in the normally developed shoots, particularly when wellexposed. More and longer secondary shoots occurred on the normally developed shoots than on the underdeveloped shoots. No difference was found in the number of primary leaves (leaves on primary shoots) betweennormally developed and underdeveloped shoots, although the leaf area was much larger in the case of the former.  Normally developed shoots had more and larger secondary leaves (leaves on secondary shoots), while all the leaves that developed in the shaded canopies were found to be larger than those in the well-exposed canopies with a higher leaf area:mass ratio. The normally developed shoots seemed to have a greater potential for producing a higher yield, with better quality, than the underdeveloped shoots, as they have a more desirable leaf area composition in addition to a larger total leaf area per shoot

Expression of DC-SIGN and DC-SIGNRs in placentas of HIV-positive patients

Background. Human dendritic cell-specific intracellular adhesion molecule-3 (ICAM3)-grabbing non-integrin (DC-SIGN) is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is suggested that HIV may become adsorbed to DC-SIGN on Hofbauer cells as part of the mechanism of mother-to-child HIV transmission. A possible mechanism of transfer of the virus from the Hofbauer cells to the fetus is the subsequent adsorption to DC-SIGN-related molecules (DC-SIGNRs), present on immediately adjacent capillary vascular endothelium. However, data on DC-SIGN and DC-SIGNR expression in the placenta are few. Methods. Forty term placentas from HIV-positive mothers and 21 term placentas from HIV-negative mothers underwent immunohistochemistry staining for DC-SIGN and DC-SIGNR expression. Five random sets of 10 villi were assessed, and the average number of positive cells were counted in each case. In addition, where possible, maternal and cord blood viral loads and maternal CD4+ counts were performed in the HIV-positive group only. Results. The median maternal CD4+ count was 377 cells/μl and 27% of participants had undetectable viral loads; the median detectable viral load was 3.72 log. Most (97%) of the cord bloods tested in infants from HIV-positive mothers had lower than detectable viral loads. HIV-positive cases had significantly greater expression of both DC-SIGNRs (median values in HIV-positive cases, 14.5 positive cells/10 villi (pc/10villi), compared with 11 pc/10villi in HIV-negative cases, p=0.020) and DC-SIGN (median value in HIV-positive cases, 26.5 pc/10villi, compared with 23 pc/10villi in HIV-negative cases, p=0.037). DC-SIGNR expression was also noted in Hofbauer cells and decidual macrophages in addition to endothelium (reported currently). There was no difference in expression of DC-SIGN and DC-SIGNRs in patients with or without chorioamnionitis, but there was an inverse relationship between DC-SIGN and DC-SIGNR expression and maternal CD4+ counts in HIV-positive cases. Conclusion. Both DC-SIGN and DC-SIGNR expression were higher in placentas from HIV-positive mothers compared with HIV-negative cases. These lectins may be potential new therapeutic targets for preventing vertical transmission of HIV

Expression of DC-SIGN and DC-SIGNRs in placentas of HIV-positive patients

Background. Human dendritic cell-specific intracellular adhesion molecule-3 (ICAM3)-grabbing non-integrin (DC-SIGN) is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is suggested that HIV may become adsorbed to DC-SIGN on Hofbauer cells as part of the mechanism of mother-to-child HIV transmission. A possible mechanism of transfer of the virus from the Hofbauer cells to the fetus is the subsequent adsorption to DC-SIGN-related molecules (DC-SIGNRs), present on immediately adjacent capillary vascular endothelium. However, data on DC-SIGN and DC-SIGNR expression in the placenta are few. Methods. Forty term placentas from HIV-positive mothers and 21 term placentas from HIV-negative mothers underwent immunohistochemistry staining for DC-SIGN and DC-SIGNR expression. Five random sets of 10 villi were assessed, and the average number of positive cells were counted in each case. In addition, where possible, maternal and cord blood viral loads and maternal CD4+ counts were performed in the HIV-positive group only. Results. The median maternal CD4+ count was 377 cells/µl and 27% of participants had undetectable viral loads; the median detectable viral load was 3.72 log. Most (97%) of the cord bloods tested in infants from HIV-positive mothers had lower than detectable viral loads. HIV-positive cases had significantly greater expression of both DC-SIGNRs (median values in HIV-positive cases, 14.5 positive cells/10 villi (pc/10villi), compared with 11 pc/10villi in HIV-negative cases, p=0.020) and DC-SIGN (median value in HIV-positive cases, 26.5 pc/10villi, compared with 23 pc/10villi in HIV-negative cases, p=0.037). DC-SIGNR expression was also noted in Hofbauer cells and decidual macrophages in addition to endothelium (reported currently). There was no difference in expression of DC-SIGN and DC-SIGNRs in patients with or without chorioamnionitis, but there was an inverse relationship between DC-SIGN and DC-SIGNR expression and maternal CD4+ counts in HIV-positive cases.  Conclusion. Both DC-SIGN and DC-SIGNR expression were higher in placentas from HIV-positive mothers compared with HIV-negative cases. These lectins may be potential new therapeutic targets for preventing vertical transmission of HIV

Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. II. Physiological Activity

In this study, the physiology of normally developed and underdeveloped shoots is compared in an attempt toquantify the effect of shoot heterogeneity in a Shiraz/Richter 99 vineyard, located in the Stellenbosch area of theWestern Cape, South Africa. Comparisons are made between normally developed and underdeveloped shoots fromshaded and well-exposed canopies. In the first five weeks after véraison, photosynthetic and transpiration rates,stomatal conductance and water-use efficiency (WUE) decreased as berry ripening progressed, while the internalCO2 levels of the leaves increased. Since differences in activity between individual leaves from normally developedand underdeveloped shoots only became apparent in the third week after véraison, it seemed as if the leaf area pershoot played a more important role than the photosynthetic output per unit leaf area in determining photosynthetatesupply to the rest of the vine up to this stage. From the third week after véraison, higher levels of photosynthetateswere produced by normally developed shoots than by underdeveloped shoots, due to the larger effective leaf areaper shoot as well as the higher photosynthetic activity per unit leaf area. This points to premature senescence of theleaves on underdeveloped shoots. The quantity and quality of the yield from normally developed shoots are expectedto benefit from the higher physiological output of the leaves. The enhancing effect on leaf functioning induced bycanopy exposure became apparent from the third week after véraison

Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. III. Leaf Chlorophyll Content

In this study, the leaf chlorophyll content of normally developed and underdeveloped shoots was compared in anattempt to quantify the effect of shoot heterogeneity in a Shiraz/Richter 99 vineyard, located in the Stellenbosch areaof the Western Cape, South Africa. Comparisons are also made between normally developed and underdevelopedshoots from shaded and well-exposed canopies. No positive correlation was found between the photosyntheticactivity and the chlorophyll concentration of the leaves at five weeks after véraison. Equal amounts of chlorophyllper cm2 and a non-significant difference in the assimilation rate were calculated for the leaves of normally developedand underdeveloped shoots. No significant differences were found between the shaded and well-exposed canopies. Ittherefore appears that it is the effective surface area per leaf or per shoot rather than the chlorophyll concentrationor activity that may be responsible for any apparent difference in the photosynthetic output of the leaves fromnormally developed and underdeveloped shoots in shaded or well-exposed canopies

Influence of territorial aggressiveness of ostrich males on egg production of companion female ostriches

(South African J of Animal Science, 2000, 30, Supplement 1: 68-69

Laboratoriumstandaardisasie en kwaliteitskontrole in antistolterapie

The original publication is available at http://www.samj.org.za[No abstract available]Publishers' versio

Quality assessment and primary uses of harvested rainwater in Kleinmond, South Africa

water security, reaching the Millennium Development Goals (MDGs) and sustaining water resources. The microbial and chemical quality of RWH samples collected from tanks in a sustainable housing development in Kleinmond, South Africa, were monitored. Results indicated that the tank water quality was within all the chemical standards (cations and anions) analysed for potable water. However, the counts of the indicator organisms, for example, total coliforms and Escherichia coli, exceeded the guidelines stipulated by the Department of Water Affairs and Forestry (1996). The microbial analysis results thus indicate that the tank water was not fit for potable use without treatment. A social research project was then conducted to describe, amongst others, the condition of the tank and the users’ knowledge of the RWH system. In addition, demographic data, viz., gender, household size and employment status, etc., were gathered in order to provide a socio-economic background description of the study population. Data were gathered by means of face-to-face interviews with 68 respondents. Generally, RWH was used for washing clothes and for cleaning inside and outside the houses. This study noted that without acceptance and necessary training to maintain and use the tank optimally, it is possible that social development projects, such as the one in Kleinmond, will not be sustainable.Keywords: domestic rainwater harvesting; microbial and chemical quality; social perception; acceptanc

The influence of stocking rate and male:female ratio on the production of breeding ostriches (Struthio camelus spp.) under commercial farming conditions

The study provides information on the reproductive performance of ostriches maintained at different stocking rates and male:female (M:F) ratios under intensive commercial conditions in the Little Karoo, South Africa. Breeding ostriches are concentrated on relatively small areas and through trampling have a most significant impact on the vegetation in the Little Karoo. Reproductive performance, as influenced by stocking rate and M:F ratio, was investigated. Stocking rates for the large flocks ranged from 114 to 210 birds/ha, and stocking rates for smaller flocks ranged between 9 to 13 birds in 0.13 ha and 0.30 ha camps, respectively. The different M:F ratios investigated, were 1M:1F (pairs), 1M:2F (trios) and 1M:3F (quads), for breeding systems maintained in 0.06 ha camps. In almost all breeding systems total and average egg production, fertility and hatchability were compromised when stocking rate was increased. High stocking rates were detrimental to the reproductive performance and reproductive behaviour of the flocks. Increasing the number of females per male had no negative influence on the reproduction traits, with a significantly higher production observed for breeding quads. Our findings indicated that ostrich breeding flocks can be maintained at stocking rates higher than those presently used on commercial ostrich farms. Breeding pairs, trios and quads can also be maintained on smaller areas, with acceptable production levels. Increasing stocking densities will have a possible inhibitory effect on the establishment of territories and use of space, thereby impacting on the reproductive behaviour of ostrich females and males in large flocks, respectively. This has important implications in terms of the intensification of ostrich farming especially in areas that are characterised by vegetation that is exposed to the trampling effect of ostriches. South African Journal of Animal Science Vol.34(2) 2004: 87-9

Heritability of live weight and condition score in a Holstein herd and correlations with milk traits – preliminary estimat

Genetic and environmental parameters for live weight and condition score have been determined for Holstein cows. Genetic correlations with milk traits were also derived. Monthly records were modelled by cubic splines, while the direct, additive effects of animal and the temporary environment (defined as cow environmental effects within lactations) were fitted as random. Lactation number interacted with monthly trends in cow live weight. Cows lost weight in the early part of the lactation. This reduction in live weight was probably because of a loss in body reserves, as suggested by a lower condition score. Cows gained live weight towards the end of lactation. The ultimate live weight of cows increased with parity because of ongoing growth. The heritability (h²) estimate for live weight was high at 0.65 ± 0.04, albeit still within the expected range. Condition score had a medium h² of 0.24 ± 0.05. Genetic and phenotypic correlations of live weight with milk yield were positive, i.e. 0.19 ± 0.14 and 0.12 ± 0.05, respectively, while correlations of condition score with milk yield were negative, i.e. 0.42 ± 0.15 and -0.17 ± 0.04, respectively. Although live weight could be used as an indirect indicator of feed intake and efficiency of milk production, other body conformation traits could also be used. There is a need in the South African dairy industry for a selection index based on production parameters and some traits such as live weight, condition score or specific conformation traits. However, a large participation of animals in milk recording and measurement of such traits is a prerequisite for such developments. South African Journal of Animal Science Vol. 36(2) 2006: 79-8