Showing items 421 - 438 of 438

Utlwa Ntate

Uyingcwele Nkosi yamaviyo

Vegetation ecology of the Camdebo and Sneeuberg regions of the Karoo biome, South Africa

  • Authors: Palmer, Anthony Riordan
  • Date: 1989
  • Subjects: Plants -- South Africa -- Great Karoo Great Karoo (South Africa)
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4173 , http://hdl.handle.net/10962/d1002021
  • Description: An hierarchical syntaxonomic classification of the vegetation of the Camdebo and Sneeuberg regions of the karoo biome is presented as a second approximation after the earlier work by Acocks (1953). Details on the geomorphology, geology, climate, and early vegetation history of the area are given. The vegetation of the study area was stratified with the aid of Landsat imagery and the community classification was generated using two-way indicator species analysis (Twins pan) which produced ordered phytosociological tables. Tabular comparisons and final sorting of tables are according to the methods and techniques of the ZiirichMontpellier school of phytosociology. Syntaxonomic ranks are defined as five classes, nine orders and seventeen communities. The classes are Grasslands, Karoo Shrublands, Karoo Dwarf Shrublands, Sub-tropical Transitional Thicket, and Riparian Thicket. The distribution of syntaxa corresponds with the steep precipitation gradient experienced in the study area. These vegetation concepts are applied to the description of the flora of the Karoo Nature Reserve and an analysis of the total flora of the reserve is provided. The communities of the pediments, which contain the highest number of endemics, are poorly conserved. I test the validity of the vegetation classification by interpreting the results of an analysis of soils within the hypothesized vegetation units. There is a gradient of increasing Na, silt and pH levels from the Shrublands and Grasslands to the Succulent and Grassy Dwarf Shrublands of the pediments. A qualitative model of the vegetation history during the glacial-interglacial sequence in the Graaff-Reinet region of the eastern Cape is presented. Using a descriptive approach, the distribution patterns of 68 taxa, which are differential species for Karoo Shrublands, Succulent Thicket and Karoo Dwarf Shrublands, are investigated relative to major southern African biomes. The results indicate that a large proportion of the differential species in the phytosociological classification show affinity with Grassland and Savanna Biomes. Three species groups encountered in the Dwarf Shrublands show affinity with the Nama-Karoo biome. The differential species of the Succulent Thicket have a predominantly subtropical distribution. Using an historical approach, the palaeoenvironment of the region during the past 20 000 years is discussed briefly. On the basis of the descriptive and historical perspectives, a qualitative model of vegetation history is presented. The Succulent Thicket may have become established on edaphically favourable sites in the ameliorating conditions of the warmer, wetter Holocene subsequent to the Last Glacial Maximum. The Dwarf Shrubland and Succulent Dwarf Shrubland are depauperate in relation to ccmmunities in other southern African biomes, but the relatively large number of endemics suggests a long history in the region. Their differential species groups occur under arid conditions, accompanied by soils with high base and fertility status. The Dwarf Shrublands may have been more extensive during the drier glacial times on those sites currently occupied by Shrubland. The Shrublands display the expected affInity with the Grassland and Savanna Biomes. The small number of endemics suggest that these communities may have occupied the region in the period since the Last Glacial Maximum. Species with Succulent Karoo Biome affInity are poorly represented. The reliability of using Landsat products to detect and map the vegetation of the region is assessed. The manual classification of Landsat standard products provides a poor reflection of the vegetation of the arid, sparsely-vegetated bottomlands and pediments. The products provide good representation of the boundaries of thicket vegetation, but this uni-temporal approach does not distinguish between floristically different thicket communities. After analyzing digital Landsat data, I suggest that the multi-spectral scanner detects the boundaries of broad soil pedons and geological formations in areas of low vegetative cover. I describe and map the vegetation categories of the region after manual interpretation of six Landsat scenes. This is an effIcient, cost-effective method of mapping vegetation in extensive regions. The mapping units do not reflect the syntaxonomic classification, representing rather an integration of physiographic, pedological, geological and floristic information. With the view to improving the classification of these units, I develop a qualitative model of the natural resources of the region using an expert system
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  • Date Issued: 1989

Wage increases for goods transport workers

  • Authors: COSATU, TGWU
  • Date: Dec 1989
  • Subjects: COSATU, TGWU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/115546 , vital:34156
  • Description: T&G has been sitting on the Goods Transport Industrial Council in the Transvaal for three years. T&G negotiates with the bosses’ organisation, the Motor Transport Owners Association (MTOA) once a year. About 500 goods transport companies belong to the MTOA and these bosses employ about 16 000 workers. T&G has about 6 000 goods transport members in the Transvaal. So it is important to negotiate a good deal for T&G workers but also for the many workers we have not organised at this point. There are many things that we negotiate around on the council. Here are some of the things we won this year: All goods transport workers who earn the council minimum wage will get a wage increase. Workers who earn below R118 a week will get a 19% increase and workers who earn above R118 will get a 16% increase. So for example, a general worker was getting R84.61 and will now get R100,64 a week. And a heavy duty driver was getting R130,18 and will now get R151. We also won a night out allowance increase. Drivers will get R20,40 a night and general workers R17,60. The sick benefit and holiday pay bonus now goes to all workers in the transport industry in Transvaal and not only to the drivers.
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  • Date Issued: Dec 1989

Wealth or welfare?: a survey of local responses to government's proposed urbanisation policy in the greater Algoa Bay area

  • Authors: Taylor, Beverley J
  • Date: 1989
  • Subjects: South Africa -- Group Areas Act Urbanization -- South Africa Cities and towns -- Africa Freedom of movement Local government -- South Africa -- Eastern Cape Joint management centres South Africa -- Politics and government Algoa Bay (South Africa)
  • Language: English
  • Type: Book , Text
  • Identifier: http://hdl.handle.net/10962/1784 , vital:20225 , ISBN 0868101761
  • Description: This Working Paper sets out to investigate what has generally been taken for granted as part and parcel of the urbanisation and development process in South Africa, and to relate this to current government strategies. There has been no comprehensive policy for coping with urbanisation in South Africa. In particular, the urbanisation of Africans has not been accepted as an inevitable process. Instead, past policies have been guided by apartheid ideology and have tended to address only specific issues relating to urbanisation. Essentially, policies have attempted to control the urbanisation process through various pieces of legislation directed at, for example, housing, population migration, industrial decentralisation etc. Such legislative measures, rather than presenting a coherent urbanisation policy, have provided the main tools for the South African state to control and direct the urbanisation process in the country as a whole. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
  • Full Text:
  • Date Issued: 1989

Work in Progress Issue no.58 - The teenagers of Tumahole

  • Authors: WIP
  • Date: April 1989
  • Subjects: WIP
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/111464 , vital:33462
  • Description: On January 11, South Africa's minister of home affairs and of communications, Stoffel Botha, warned Work In Progress that an examination of the publication was underway in terms of state of emergency regulations. Over a year before, Botha had warned W/P that unless it ceased 'systematic publication of subversive propaganda', he would act against it. The January 11 warning involved possible closure of W/P for up to six months, or imposing a pre-publication censor - a state official with powers to censor the contents of the publication. Over the next weeks, enormous support was expressed for W/P and its publishing policy. This came from editors of mainstream newspapers, trade unions, political organisations, religious bodies and a host of other interests and organisations. The Congress of South African Trade Unions noted that 'censorship of WIP is a direct attempt to stifle free and open debate, and to prevent the flow of information so vital to the building of democracy'. The National Union of Mineworkers said that 'every issue of W/P that does not come out will be a loss to our members', while the National Council of Trade Unions referred to the publication's 'intelligent and fearless analysis of the political, social and labour trends in our country'. From within the media world, Business Day editor Ken Owen spoke of W/P as a 'reliable, intelligent and ethically impeccable publication', while Tertius Myburgh of the Sunday Times called W/P 'an invaluable source of information which deserves to be heard by all who are interested in serious affairs in South Africa'. Representatives of foreign governments strongly condemned proposed action against W/P and other publications, and a number made direct representations to the South African government. Two weeks after Botha's warning, WIP responded to his threat of closure in a 40-page memorandum dealing with the emergency regulations in general, and the nature of the publication in particular. Botha turned down a suggestion that he meet with a delegation from the publication - and then a blanket of silence descended. By mid-February, two publications warned at the same time as W/P had been suspended for three months, and W/P began pushing Botha to respond to the representations made. Finally, on March 2, Botha's office informed WIP's publishers that no action was being contemplated in terms of the media emergency regulations. It is not for W/P to speculate on why the minister has chosen to act against some publications, and not others. The media emergency regulations involve arbitrary decisions and personal opinion. There is little point in seeking logic within arbitrariness. But it is worthwhile re-stating WIP's position on publishing: that not only do all South Africans have the right to be fully and accurately informed by a wide range of opinions, debates and analyses and reporting. In addition, freedom of speech of its nature guarantees the right of publication - and the right of readers to be exposed to diversity and contradiction. WIP has always been happy to allow readers to make their own choices on the basis of a wide range of information and views. This is the opposite of propaganda, which seeks to impose one view while suppressing others. In this battle for survival with the ministry of home affairs W/P has no doubt which side supports the publication of systematic propaganda. This edition of WIP is unavoidably late - held back until the outcome of the threatened closure had been finalised. No action is currently contemplated against the publication in terms of media emergency regulations at present - although the state still has much in its arsenal. But WIP intends surviving - and sees a long-term future for its publishing programme. One part of this future is financial stability - a crucial component of independent publishing. Ensuring financial stability, together with ever-increasing costs in paper, printing, reproduction and postage have forced W/P to raise its rates. But these increases are modest - way below rates of inflation - and in some cases are the first for over three years. The editors thank all those who supported W/P in its most-recent battle for survival - and look forward to ongoing and increasing support from the most important component of any publication: its readers.
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  • Date Issued: April 1989

Work in Progress Issue no.59 - Roads to congress

  • Authors: Work in progress (WIP)
  • Date: July 1989
  • Subjects: WIP
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/112078 , vital:33545
  • Description: South Africa is moving into its fourth year of continuous emergency rule. And with the exception of a few months during 1986, some areas are entering their fifth year under these conditions. The effects of permanent emergency rule have been traumatic and wide ranging. Under emergency rule, a fundamentally anti-democratic state has been able to impose itself on an unwilling people without being subject to scrutiny, discussion or legal opposition. And while South Africa pre-emergency had almost none of the rights and freedoms associated with democracy, the last few years have stripped society of the last vestiges of rule by consent. The nature of the emergency has changed. It began as an aggressive attack on the mass democratic movement and the situation of 'ungovernability' that popular insurrection created. It has changed to become an all-encompassing political strategy, a last defence against ideas which refuse to die. For while organisations have been smashed, the ideas and aspirations which grew from the turbulent early 1980s are showing signs of re-emerging. In this context it may well be true that this government cannot rule without recourse to emergency powers of enormous magnitude. It may also be true that suppression of information, debate and opposition, and unrestrained powers for security forces, are a necessary precondition for an apartheid government to rule a subject people. Government sources have often argued that emergency powers are designed to create a stable context for 'reform'. But what reforms of substance have been offered since the first emergency was declared in July 1985? Looking nervously over a shoulder at far-right interests threatened by the most superficial aspects of deracialisation is hardly an indication of reform. Proposals for a consultative council incorporating Africans are not only tired and bankrupt. Their uncomfortable similarities to the 'toy telephone' Native Representative Council of the 1940s ensures that even the most moderate of black interests will spurn such ideas. Only the discredited, the opportunistic, or those with no following or power base can contemplate participation. Emergency rule - like so many of the preconditions for maintaining apartheid - has created further disease and distortion in society. When the state's institutions of repression - notably police and military - have the free reign granted by emergency powers, it is no surprise that death squads operate seemingly without reprisals. When members of the 'security forces' have the power to incarcerate apartheid's opponents indefinitely, it is no surprise that assassinations, abductions and 'dirty tricks' departments flourish as additional means to remove organised opposition and resistence. It is six weeks since David Webster's death swelled the growing record of political assassinations, assaults and abductions. Over 12 years of publishing, David was a good friend to Work In Progress, writing for, distributing and supporting the publication. Fie was guest speaker at WIP's tenth anniversary celebration. And while police seem unable to find those specifically responsible for his murder, those who have created the atmosphere of emergency rule are the real culprits. It is but one small step from exercising legal powers to detain, ban and suppress, to the extra-legal actions of assassination and terror. Emergency rule will presumably continue until at least after the September general election. The National Party is keen to stay as far from the international spotlight as possible until after these elections. In particular, the new American administration, while clearly right wing, may have new and unpleasant approaches to sanctions and international pressure on South Africa. Internally, the opposition which can be generated in the election - be it from the far right or from those committed to democracy - clearly worries a government based on such shaky foundations. Government planners will still recall the organised resistance to the election of Indian and coloured houses which made such a mockery of the tricameral constitutional initiative. When a government, bankrupt in ideas and initiative's bent on holding power for its own sake - and has means like the state of emergency to enforce is rule - the prospects for any constructive negotiated change are indeed bleak.
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  • Date Issued: July 1989

Work in Progress Issue no.60 - Negotiations, another site of struggle

  • Authors: Work in progress (WIP)
  • Date: Sep 1989
  • Subjects: WIP
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/112067 , vital:33544
  • Description: The air is thick with talk about negotiating South Africa's future. From the government of FW de Klerk and PW Botha to the rulers of England, the Soviet Union, the United States of America and West Germany; from the National and Democratic Parties to the ANC and SACP; from the 'mass democratic movement' to Inkatha, the Reserve Bank and those financial, commercial and industrial interests which make up South Africa's capitalist class: all have raised the vision of a negotiated settlement to the conflict over apartheid and South Africa's future. But matters are never that simple - especially in a conflict between interests which may be fundamentally opposed. Some years back, the ANC drew a distinction between 'talks' and 'negotiations' - a distinction which many commentators on South Africa seem unable to grasp. Additionally, serious analysts have noted that the idea and process of negotiation is itself an arena of struggle and contestation. This is true not only for opposition and anti-apartheid forces, but for the South African government itself. There is nothing predetermined or linear about a negotiation process - even if most parties are in agreement that, in principle, negotiated settlements are preferable to a 'fight to the death'. Negotiation is but one weapon in the arsenal of struggle-for all parties. Other weapons may-at various times - include armed force and military action, sanctions and international pressure, diplomacy and lobbying, destabilisation and disruption, mass politics and mobilisation, detentions, assassinations and vigilante activity. Many of these can be the tactics of struggle for the interests involved in the South African conflict: not only for the South African government, but also the Soviets, Americans or British; not only for the ANC and SACP, but also for Inkatha and the South African state's security apparatuses. And agreement in principle to negotiate is a long way from sitting across a table discussing the dismantling of apartheid and a postapartheid dispensation. Neither does a commitment to negotiations exclude the use of all tactics to create a climate most conducive to specific interests represented - be they the interests of white supremacy, imperialism, democracy, conservatism, capitalism or socialism. All the major actors involved in talking about negotiations know that well: it is only those who comment on and analyse their actions who often miss the point. For the ANC, then, there is no necessary contradiction between exploring negotiations and an armed struggle; For the SACP, working-class organisation, insurrectionary potentials and socialism are not contradicted by an agreement - at a particular point - to negotiate the dismantling of apartheid; For FW de Klerk, there is no conflict between the language of negotiation, a racial election and a state of emergency; For governments of other countries involved in the conflict, sanctions and international pressure on both the South African state and its anti-apartheid opponents do not run counter to a strategy of negotiations; And for Inkatha and its supporters, negotiations about peace in Natal seem compatible with a strategy of repressing all who fall outside their camp. These are the issues raised in a number of contributions to this edition of Work In Progress. All parties to the 'negotiation option' have contradictions to manage, suppress or overcome within their own ranks; all parties have the intention to create a climate most conducive to their interests and agendas; and all parties will, within the limits imposed by other forces operating on them, attempt to structure any negotiation process in favour of the interests they represent and champion. In this, they will utilise methods and tactics of struggle which appear to contradict a commitment to a negotiated settlement of South Africa's racial issues. There is nothing surprising in this: for negotiations themselves are a site of struggle, influencing and influenced by rhythms and developments in other areas and tactics of political struggle.
  • Full Text:
  • Date Issued: Sep 1989

Work in Progress Issue no.61 - Defiance a measure of expectations

  • Authors: Work in progress (WIP)
  • Date: Oct 1989
  • Subjects: WIP
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/112056 , vital:33543
  • Description: This is not the first time a South African government has reached a maize of crossroads. But this time, no matter which direction is taken, the path can only swing back to a single destination, signposted: give up power to the majority. This demand is made - with different degrees of intensity - from almost every sector of influence: internal political organisations, international superpowers, local and international capital, the frontline states, even the Democratic Party within its own parliament. The taste of liberal democracy implied by police non-intervention in some of the largest demonstrations yet seen in South African history raises difficult questions for De Klerk's government. Will it send in troops next time round, and if so, at what cost? Or will the government, faced with few choices and even less room to manoeuvre, allow more and more demonstrations from a majority implacably opposed to National Party rule. The answer must depend on the extent to which the government is willing to ignore international economic and political pressure. The nature of current resistance and defiance suggests that those with allegiance to the Mass Democratic Movement believe they have the government in a corner. There is no sign that action based on this belief will stop, and the sense of achievement generated by the 'Pretoria spring' of the mid-September marches will fuel this. The state's lack of options is compounded by the space these recent concessions may give popular political organisations to build spontaneous mass mobilisation into directed and thoughtful political programmes - precisely what years of emergency rule were designed to avoid. This could yet lead to an intensified period of repression. Popular resistance and expectations are fuelled by an increasingly politicised labour movement integrated into political organisations in a way they never were in the turmoil of the 1970s and early 1980s. This 'unity in action' will ensure that the push to end minority rule occurs on the factory floor as well, sending ripples through the ranks of a capitalist class trapped between its employees and a state increasingly unable to guarantee capitalist interests. The ANC, in lobbying international forums to get its basic conditions for negotiation with Pretoria accepted, has succeeded in tapping into international desires to see resolution of the South African problem. In a changing international climate, the ANC is increasingly viewed as an organisation responsibly and thoughtfully representing the interests of the majority of South Africans. Against this, repression of those who demand basic human rights looks indefensible. The major powers involved in the 'negotiation push' are keen to rid South Africa of its 'apartheid problem'. Their major commitment is to a stable, majority government, with some form of capitalist economy. And while international governments' attitudes to sanctions vary, this pressure is growing. Sanctions will not bring down the economy or the government. But they will continue to limit the South African government's options in its strategies for holding power. Namibia, on the eve of independence, adds impetus to the feel ing that transfer of power in South Africa - possibly peaceful - may be attainable. The National Party programme of 'reform' demonstrates the impossibility of holding onto power while moving away from apartheid and minority rule. The minimum demands of the majority of South Africans remain more than the current government can consider. At every turn, the Nationalist government demonstrates that its tactics are born of reaction rather than a thoughtful strategy. It puts out the fires of resistance as and when they arise, and with little consistency in tactics. Sometimes guns are used and police are allowed free reign, while at other times there are attempts at containment. De Klerk's government may well be able to manage a holding operation, governing in the sense of maintaining partial control of society. But in the longer term, it has few real options. For at core, meeting the minimum demands of those creating the pressure - be they international powers or popular resistance forces - means relinquishing political power. Those who currently hold state power can react to mounting pressures in varying ways. But they do not have the space or options to act decisively in structuring the society to which they are responding. What remains unclear is the precise point at which the costs, in terms of political resistance, international pressure and economic decline, will become overwhelming. And equally unclear is how great these costs will be in bringing the government to that point.
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  • Date Issued: Oct 1989

Work in Progress Issue no.62/63 - Paths to Power, South Africa and Namibia face the future

  • Authors: WIP
  • Date: Dec 1989
  • Subjects: WIP
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/112045 , vital:33541
  • Description: The political map of Southern Africa is being radically redrawn. The most vivid examples of this are the pre- independence elections in Namibia, giving the Namibian people their first opportunity to exercise control over their destiny, and in South Africa the release of the seven jailed ANC leaders by a president whose predecessor swore to let them rot in jail. Even in Angola major shifts are taking place below the surface while the war drags on. Savimbi’s fighters still receive weaponry from their traditional allies, but their Western support is no longer a certainty. Establishment American voices have, for the first time, been raised against his brutal tactics. The East-West, capitalist-communist rivalries that have fostered the 14-year Angolan war are everywhere crumbling. This has been graphically symbolised by the breaching of the Berlin Wall. And as the bricks fall at the Brandenburg Gate, they take with them decades of conventional wisdoms on both sides of the Wall. In Eastern Europe, the idea that socialist economics are an adequate alternative to political democracy has been destroyed, probably permanently. For socialists, the challenge now is to demonstrate that democracy is not, as their foes maintain, the exclusive preserve of capitalist economics. The massive changes in Eastern Europe have not left the West unaffected. And they have for the first time wrought a convergence of United States and Soviet opinion on South Africa that has impacted powerfully on Pretoria. Under FW de Klerk the National Party is now hard at work attempting to restructure both the material conditions under which the process of change takes place and the economics of the society its successors will inherit. Facing a reviving and increasingly confident opposition, the National Party is now led by politicians who recognise that no minority has ever successfully held on to power without facing a revolution. Its attempts at social engineering continue both in the bantustans and in the urban areas, where concessions on group areas serve to reinforce rather than eradicate the physical separation of communities of different races - strengthening De Klerk’s own thrust for a post-apartheid society rooted in'groups' and racial separation. Economically, too, reinforcement of the existing order is underway. Deregulation and privatisation are designed not so much to 'free' the economy, but to weaken the trade union movement in the short term and, in the long term, to entrench capitalist interests so deeply that whoever inherits political power is capable of no more real a transformation than changing the colour of parliament. Nor has De Klerk abandoned his government's traditional policy of divide and rule. Today he is seeking to force a divison between between the military formations of the ANC and what he hopes will become a 'political' ANC, ideally coalesced around the released seven and Nelson Mandela. Within the opposition, however, a significant momentum is developing towards greater rather than lesser unity - both between the ANC and its internal allies and more generally, among the majority of antiapartheid and democratic forces. Despite this, the democratic movement would be foolhardy to ignore the lessons of Namibia. The first of these is that the simple assertion by the popular movements of their representivity is not in itself a guarantee of overwhelming support. Secondly - and this is a message De Klerk’s strategists will have received and understood - that, through the DTA, Pretoria has for the first time succeeded in creating an organisation capable of winning sufficient legitimacy to gain the votes of almost one in three Namibians. * A steady increase in inflation has forced us, reluctantly, to increase the price of WIP - an increase so far limited to subscriptions. Full details are published on the inside back cover of this edition. For this new annual rate, however, subscribers will be getting eight editions rather than the current six - a first step, we hope, to WIP becoming a monthly journal.
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  • Date Issued: Dec 1989

Workers Tax - How to calculate your tax under the new SITE system

  • Authors: TURP
  • Date: 1989
  • Subjects: TURP
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/135681 , vital:37288
  • Description: Through their organisations, workers have raised ill many problems with the tax system in South Africa. The main issue is that although everyone in South Africa pays tax, the majority of the people cannot choose their government and so they have no say in how their money is spent. Only 14% of South Africans can vote for the government. However, the government decides howto use everyones’ money. Clearly, then, the payment of tax is a political issue. Everyone should have an equal say in how their money is spent. Tax is also an issue that particularly concerns workers. Since the introduction, in 1988, of the Standard Income Tax on Employees (SITE), workers have had their tax assessed by their employers. How this happens and the problems that this can cause, are set out in this booklet. Many workers may have paid too much tax between March and July this year. They should be refunded the money. It is important to check and see if this has happened. The booklet will explain howtodo this and will teach people how to work out how much tax they should be paying. Tax is also being taken up as a womens' issue because married women pay more tax than anyone else.
  • Full Text:
  • Date Issued: 1989

Xinyimpfana xa Xikwembu

Yankele izipho zethu Nkosi

Yazisa Uyihlo Nonyoko

Yihla Moya, usiKhumbule

Zinc inhibition of cell division : its relevance to cancer cells and possible mechanism of action

  • Authors: Skeef, Noel Samuel
  • Date: 1989
  • Subjects: Cell division , Cancer cells -- Growth -- Regulation , Zinc in the body , Zinc -- Physiological effect , Cancer -- Research
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4144 , http://hdl.handle.net/10962/d1016266
  • Description: A description of two techniques used extensively in this study namely cell counting with a "cell counting plate" and argentation TLC for the separation of ω -6 -fatty acids is given. Zn supplementation into GM of two malignant (BL-6 and Hep- 350) and a non-malignant (LLC-MK) cell line/s resulted in an increased uptake of Zn by the cells and progressively suppressed proliferation of particularly the malignant cells. Zn chelation by EDTA suppressed in vitro proliferation of all 3 cell line, this effect being more pronounced in the malignant cells. A dietary Zn deficiency resulted in alopecia in mice and both a dietary Zn deficiency and Zn excess reduced growth of BL-6 tumours implanted subcutaneously in mice. Zn supplementation into GM progressively increased the uptake of [1-¹⁴C]-LA by BL-6 and LLC-MK cells but had a very slight though irregular effect on this parameter in the Hep- 350 cells. Zn supplementation also stimulated desaturase activity in the BL-6 cells. These results suggested that there are select cell lines whose Δ⁶-desaturase activity responds positively to Zn supplementation (e.g. the BL-6 cells). Delta-6-desaturase activity was also assayed in microsome preparations from different tissues. No enzyme activity was detected in the microsomes prepared from the BL-6 tumours. There was no significant effect with the addition of Zn or EDTA, on Δ⁶-desaturase activity of the regenerating liver microsomes. In the resting liver microsomes this enzyme activity was reduced only when EDTA and Zn were added together and when EDTA was added to the reaction medium as well as to the microsome preparations 2 hr before the enzyme activity assay was initiated. The results of these experiments suggested that the Δ⁶-desaturase enzyme in the microsome preparations may have had an adequate amount of Zn with further additions having no stimulatory effect on the enzyme. Two independent mechanisms of control of cell proliferation by low and high Zn are suggested to operate.
  • Full Text:
  • Date Issued: 1989

APDUSA Views

Population structure, production, growth, reproduction and the ecology of Atherina breviceps Valenciennes, 1935 (Pisces : Atherinidae) and Gilchristella aestuaria (Gilchrist, 1914) (Pisces : Clupeidae), from two southern Cape coastal lakes

  • Authors: Ratte, Theodore Wilhlelm
  • Date: 1989-01
  • Subjects: Silversides , Clupeidae -- South Africa -- Cape of Good Hope
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/50878 , vital:43029
  • Description: Over the period October 1978 to January 1981, a total of 147 853 Atherina breviceps with a total biomass of 55 2B0,7 g and 107 046 Gilchristella aestuaria with a total biomass of 33 708,9 g were collected in the Swartvlei System and 151 531 A. breviceps with a total biomass of 727 795,0 g and 51 258 G. aestuaria with a total biomass of 12 231,5 g were collected in Groenvlei, to determine their population structure, production, growth, reproduction and ecology in both systems. A. breviceps and G. aestuaria were collected from nine and eleven estuaries respectively, including Groenvlei, along the Cape coast to determine the degree of genetic divergence of both these two species in Groenvlei. It was found that the mature 0-year-old A. breviceps and the 2-year-old G. aestuaria dominated the catches in the Swartvlei System, whereas the juvenile 0-year-olds and 1-year-olds of both species respectively, dominated the catches in Groenvlei. The Swartvlei System and Groenvlei produced respectively between 10-12 metric tons of A. breviceps and between 5-3 metric tons of G. aestuaria annually. A. breviceps and G. aestuana in the Swartvlei System and Groenvlei attain observed ages of between 3 years and 7-8 years respectively. The main spawning period for both species is between spring-autumn in Groenvlei and for A. breviceps in the Swartvlei System. G. aestuaria has a continuous winter-summer spawning in the Swartvlei System. A. breviceps and G. aestuaria in Groenvlei have diverged to such an extent from these two species' populations in other systems, that A. breviceps and G. aestuaria in Groenvlei should receive a priority conservation status. , Thesis (PhD) -- Faculty of Science, 1989
  • Full Text:
  • Date Issued: 1989-01
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